Terminal, wireless communication method, and base station

Abstract

A terminal according to one aspect of the present disclosure comprises: a reception unit that receives information indicating one or more candidate cells, information pertaining to a timing advance acquisition method for the candidate cells, and cell switch command control information indicating a cell switch to a specific candidate cell; and a control unit that uses the information pertaining to a timing advance acquisition method for the candidate cells to determine whether or not to apply a timing advance procedure to the specific candidate cell after receiving the cell switch command control information.

Description

Terminal, wireless communication method and base station

[0001] The present disclosure relates to a terminal, a wireless communication method, and a base station in a next-generation mobile communication system.

[0002] Long Term Evolution (LTE) has been specified for the Universal Mobile Telecommunications System (UMTS) network with the aim of achieving higher data rates and lower latency (Non-Patent Document 1). Also, LTE-Advanced (3GPP Rel. 10-14) has been specified with the aim of achieving higher capacity and more advanced features than LTE (Third Generation Partnership Project (3GPP (registered trademark)) Release (Rel.) 8, 9).

[0003] Successor systems to LTE (e.g., 5th generation mobile communication system (5G), 5G+ (plus), 6th generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 or later, etc.) are also being considered.

[0004] 3GPP TS 36.300 V8.12.0 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8)”, April 2010

[0005] In future wireless communication systems (e.g., NR), the use of L1L2-triggered mobility (LTM) defined in Rel. 18 when a terminal (user terminal, User Equipment (UE)) moves between cells is being considered. If the LTM of Rel. 18 is applied, the interruption time of cell switching can be shortened.

[0006] In the LTM procedure of Rel. 18, it is assumed that after a UE receives control information instructing a cell switch, RACH-based LTM using a random access procedure for a candidate cell / target cell and RACH-less LTM not using a random access procedure are supported. Also, as a TA acquisition method for a candidate cell, in addition to a method using a random access procedure, a method of TA acquisition on the UE side (e.g., UE-based TA measurement) is also assumed to be supported.

[0007] There has been insufficient consideration given to how to control the LTM procedure (e.g., RACH-based LTM / RACH-less LTM) when a method for TA acquisition on the UE side (e.g., UE-based TA measurement) is configured.

[0008] Therefore, one of the objectives of the present disclosure is to provide a terminal, a wireless communication method, and a base station that can perform cell switching appropriately even when a method of acquiring TA on the UE side (e.g., UE-based TA measurement) is supported.

[0009] A terminal according to one aspect of the present disclosure has a receiving unit that receives information indicating one or more candidate cells, information regarding a timing advance acquisition method for the candidate cells, and cell switch command control information that instructs a cell switch to a specific candidate cell, and a control unit that determines whether or not to apply a timing advance procedure to the specific candidate cell after receiving the cell switch command control information based on the information regarding the timing advance acquisition method for the candidate cell.

[0010] According to one aspect of the present disclosure, even if a method of acquiring TA on the UE side (e.g., UE-based TA measurement) is supported, a cell switch can be performed appropriately.

[0011] Figure 1A is a diagram showing an example of UE mobility in Rel. 17. Figure 1B is a diagram showing an example of UE mobility in Rel. 18. Figure 2 is a diagram showing an example of LTM considered in Rel. 18. Figure 3 is a diagram showing the process between a UE and a base station (gNB) for LTM in Rel. 18. Figure 4 is a diagram showing the process of fast DL synchronization between a UE and a base station (gNB) for LTM in Rel. 18. Figure 5 is a diagram showing the process of fast UL synchronization between a UE and a base station (gNB) for LTM in Rel. 18. Figure 6 is a diagram showing an example of a timing advance group (TAG) to which cells included in a cell group belong. Figure 7 is a diagram showing an example of a MAC CE for a timing advance command. Figure 8 is a diagram showing another example of a MAC CE for a timing advance command. Figure 9 is a diagram showing an example of TAG configuration when TAG ID association is supported for candidate cells. Fig. 10 is a diagram showing an example of an LTM procedure using UE-based TA measurements. Fig. 11 is a diagram showing an example of an LTM procedure according to the first embodiment. Fig. 12 is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment. Fig. 13 is a diagram showing an example of a configuration of a base station according to an embodiment. Fig. 14 is a diagram showing an example of a configuration of a user terminal according to an embodiment. Fig. 15 is a diagram showing an example of hardware configurations of a base station and a user terminal according to an embodiment. Fig. 16 is a diagram showing an example of a vehicle according to an embodiment.

[0012] (Inter-cell mobility) It is being considered that a UE performs UL transmission to one or more cells / TRPs. The following scenario 1 or scenario 2 can be considered as a procedure in this case. In the present disclosure, the term "serving cell" may be replaced with the TRP in the serving cell. Layer 1 / layer 2 (L1 / L2) and DCI / Medium Access Control Element (MAC CE) may be replaced with each other. In the present disclosure, a physical cell identity (PCI) different from the physical cell identity (PCI) of the current serving cell may be simply referred to as a "different PCI." A non-serving cell, a cell having a different PCI, and an additional cell may be replaced with each other.

[0013] <Scenario 1> Scenario 1 corresponds to, for example, multi-TRP inter-cell mobility, but may be a scenario that does not correspond to multi-TRP inter-cell mobility.

[0014] (1) The UE receives from the serving cell the SSB configuration for beam measurement of the TRP corresponding to a PCI different from that of the serving cell, and the configuration required to use radio resources for data transmission and reception (including resources of the different PCI). (2) The UE performs beam measurement of the TRP corresponding to the different PCI and reports the beam measurement results to the serving cell. (3) Based on the above report, the Transmission Configuration Indication (TCI) state associated with the TRP corresponding to the different PCI is activated by L1 / L2 signaling from the serving cell. (4) The UE transmits and receives using a UE-dedicated channel on the TRP corresponding to the different PCI. (5) The UE must always cover the serving cell, including in the case of multiple TRPs. As in conventional systems, the UE must use common channels from the serving cell, such as the Broadcast Control Channel (BCCH) and the Paging Channel (PCH).

[0015] In Scenario 1, when the UE transmits and receives signals to and from an additional cell / TRP (a TRP corresponding to the PCI of the additional cell), the serving cell (the serving cell assumption in the UE) is not changed. The UE is configured with higher layer parameters related to the PCI of non-serving cells from the serving cell. Scenario 1 may be applied, for example, in Rel. 17.

[0016] Figure 1A shows an example of UE movement in Rel. 17. Assume that the UE moves from a cell (serving cell) with PCI #1 to a cell (additional cell) with PCI #3 (which overlaps with the serving cell). In this case, Rel. 17 does not support switching of serving cells via L1 / L2.

[0017] The additional cell is a cell that has an additional PCI different from the PCI of the serving cell. The UE can receive / transmit a UE-dedicated channel (UE-dedicated CH) from the additional cell. On the other hand, the UE needs to be within the coverage of the serving cell to receive UE common channels (e.g., system information / paging / short messages). When the UE moves out of the coverage of the serving cell, a cell switch (e.g., a process such as RRC reconfiguration) is required due to handover (also called L3 mobility).

[0018] <Scenario 2> Scenario 2 applies L1 / L2 inter-cell mobility (e.g., L1L2-triggered mobility (LTM)). L1 / L2 inter-cell mobility enables the serving cell to be changed using functions such as beam control without RRC reconfiguration. In other words, transmission and reception with a candidate cell / additional cell is possible without handover. Since handover requires RRC reconnection and creates a period when data communication is unavailable, applying L1 / L2 inter-cell mobility that does not require handover makes it possible to continue data communication even when the serving cell is changed. Scenario 2 may be applied, for example, in Rel. 18. In scenario 2, for example, the following procedure is performed.

[0019] (1) The UE receives configuration information (e.g., SSB configuration, etc.) for a cell with a different PCI (additional cell / candidate cell / target serving cell) from the serving cell (current serving cell) for beam measurement / serving cell change. (2) The UE performs beam measurement of the cell using the different PCI and reports the measurement results to the serving cell. (3) The UE may receive the configuration of the cell with a different PCI (serving cell / candidate cell configuration) via higher layer signaling (e.g., RRC). That is, pre-configuration for the serving cell change may be performed. This configuration may be performed together with the configuration in (1) or separately. (4) Based on the above report, the TCI state of the cell with the different PCI may be activated via L1 / L2 signaling according to the serving cell change. The activation of the TCI state and the serving cell change may be performed separately. (5) The UE changes the serving cell (assumed serving cell) and starts receiving / transmitting using the pre-configured UE-specific channel and TCI state.

[0020] That is, in Scenario 2, the serving cell (the serving cell assumed by the UE) is updated by L1 / L2 signaling. Scenario 2 may be applied in Rel. 18.

[0021] Figure 1B shows an example of UE mobility in Rel. 18. In Rel. 18, the serving cell is switched by L1 / L2 (e.g., DCI / MAC CE). Here, the example shows a case where the serving cell is switched from PCI #1 corresponding to the current serving cell (e.g., current serving cell) to PCI #3 corresponding to the target serving cell (e.g., target serving cell) by L1 / L2 signaling.

[0022] The UE can receive / transmit common channels (e.g., system information / paging / short messages) / UE-dedicated channels to / from the new serving cell (target serving cell #3), which may cause the UE to move out of the coverage of the previous serving cell PCI #1.

[0023] (L1L2-triggered mobility (LTM) in Rel. 18) Figure 2 shows an overview of LTM considered in Rel. 18. The UE establishes an RRC connection with the current serving cell (base station with PCI #1) and transmits an L3 measurement report. The serving cell decides to implement LTM based on the L3 measurement report and prepares for LTM with one or more candidate cells. The UE and the serving cell then perform RRC reconfiguration. Note that the one or more candidate cells may include the target cell (base station with PCI #3).

[0024] The UE, serving cell, target cell, and candidate cell perform DL synchronization. The UE performs and reports L1 (e.g., L1-RSRP / SINR) measurements of the serving / candidate / target cell. The UE, serving cell, target cell, and candidate cell perform UL synchronization.

[0025] The serving cell determines to switch the serving cell to the target cell (PCI #3) based on the L1 measurement report and sends a cell switch command to the UE. After receiving the cell switch command, the UE starts PDCCH monitoring for the target cell.

[0026] In the case of RACH-based LTM, the UE performs a RACH procedure to the target cell. In the case of RACH-less LTM, the UE sends an RRC reconfiguration complete message and transmits the first data to the target cell. This first data transmission is based on a dynamic grant or a configuration grant associated with the beam of the target cell. The target cell sends an ACK for this transmission to the UE.

[0027] Figure 3 is a diagram showing the processing between the UE and the base station (gNB) of LTM in Rel. 18. The processing of each step in Figure 3 will be described in detail below.

[0028] 1: The UE sends a measurement report message to the gNB, which determines the LTM configuration and starts preparing one or more candidate cells.

[0029] 2: The gNB sends an RRC reconfiguration message to the UE including LTM candidate cell configurations for one or more candidate cells.

[0030] 3: The UE saves its LTM candidate cell configuration and sends an RRC reconfiguration complete message to the gNB.

[0031] 4a: The UE performs DL synchronization with one or more candidate cells before receiving a cell switch command. DL synchronization for candidate cells before the cell switch command may be supported based on at least SSB.

[0032] 4b: If requested by the network, the UE performs early TA acquisition with one or more candidate cells before receiving a cell switch command. This is triggered by a PDCCH order from the source cell via a CFRA. The UE then transmits a preamble to the indicated candidate cells. To minimize data interruption in the source cell due to Contention Free Random Access (CFRA) to the candidate cells, the UE does not receive a RAR intended for TA value acquisition. The TA value of the candidate cell is indicated in the cell switch command. The UE does not maintain a TA timer for the candidate cells and ensures the validity of the TA based on the network implementation.

[0033] 5: The UE performs L1 measurements configured on the candidate cells and sends an L1 measurement report to the gNB. L1 measurements are performed as long as the RRC reconfiguration in step 2 is applied.

[0034] 6: The gNB decides to perform a cell switch to the target cell and sends a MAC CE (Cell Switch Command) to trigger the cell switch. The MAC CE includes a candidate configuration for the index of the target cell. The UE switches to the target cell and applies the configuration indicated by the candidate configuration index.

[0035] 7: If the UE does not have a valid TA for the target cell, it performs a random access procedure to the target cell.

[0036] 8: The UE completes the LTM cell switch procedure by sending an RRC reconfiguration complete message. The UE performs the RA procedure in step 7, and considers the LTM execution to be completed successfully if the random access procedure is successfully completed. In RACH-less LTM, the UE considers the LTM execution to be completed successfully if the network determines that the first UL data has been successfully received. The UE determines the successful reception of the first UL data by receiving a PDCCH specifying the UE's C-RNTI in the target cell that schedules the next new transmission of the first UL data.

[0037] Note that the RRC reconfiguration complete message may always be sent in each LTM run, and steps 4-8 may be performed multiple times for subsequent LTMs using the candidate cell configuration provided in step 2.

[0038] Figure 4 shows the process of fast DL synchronization between a UE and a base station (gNB) in LTM in Rel. 18. When configured by the network, the UE's RRC connection (RRC_CONNECTED) is possible to enable DL synchronization with a cell different from the current serving cell. This is possible by pre-activating the TCI state belonging to the cell requiring fast DL synchronization. The process of each step in Figure 4 is described in detail below. Figure 4 shows the network-triggered fast TCI state activation (fast DL synchronization) procedure.

[0039] 1: The gNB to which cell A belongs provides the UE with a list of TCI states for cell B in an RRC reconfiguration message. The gNB to which cell A belongs provides a list of TCI states for one or more cells. A fast TCI state activation procedure is performed by the UE for the one or more cells.

[0040] 2: The UE responds to the gNB with an RRC reconfiguration complete message.

[0041] 3: The gNB to which cell A belongs sends an Early TCI state activation MAC CE to initiate the early TCI state activation procedure for cell B. The early TCI state activation MAC CE may also indicate the TCI state of other cells during the TCI state activation procedure.

[0042] 4: The UE activates the TCI state of cell B indicated in the early TCI state activation MAC CE.

[0043] The UE assumes early DL synchronization of the gNB to which cell B belongs. The gNB to which cell A belongs may initiate a cell switch procedure to cell B by providing a cell switch command indicating to cell B that it is the target cell.

[0044] Figure 5 is a diagram showing the process of fast UL synchronization between a UE and a base station (gNB) in LTM in Rel. 18. When configured by the network, the UE's RRC connection (RRC_CONNECTED) is possible to enable UL synchronization with a cell different from the current serving cell. The process of each step in Figure 5 is described in detail below. Figure 5 shows the fast TA acquisition (fast UL synchronization) procedure triggered by the network.

[0045] 1: The gNB to which cell A belongs provides the UE with a TA acquisition configuration in an RRC reconfiguration message. The TA acquisition configuration includes the RRC configuration information necessary to transmit a random access preamble to cell B. The gNB to which cell B belongs then calculates the TA value to be used by the UE. For example, an LTM cell switch procedure is performed for cell B. The TA acquisition configuration may include information about one or more cells for which the TA acquisition procedure is performed by the UE.

[0046] 2: The UE responds to the gNB with an RRC reconfiguration complete message.

[0047] 3: The gNB to which cell A belongs sends a PDCCH order message to initiate the TA acquisition procedure for cell B. The PDCCH order includes information necessary to transmit a random access preamble to cell B.

[0048] 4: The UE transmits a random access preamble to cell B so that the gNB to which cell B belongs can calculate the TA value to be used by the UE (e.g., when the LTM cell switch procedure is triggered by cell B). If the gNB to which cell A belongs fails to acquire the TA, it can instruct the retransmission of the preamble to acquire the TA.

[0049] 5: When an LTM cell switch procedure is triggered for cell B, the gNB to which cell A belongs provides the UE with the TA value calculated by the gNB to which cell B belongs during the TA acquisition procedure in the LTM cell switch command MAC CE to initiate the cell switch procedure to cell B.

[0050] (Timing Advance Group) When multiple TRPs are used, the distances between the UE and each TRP may be different. The multiple TRPs may be included in the same cell (e.g., serving cell). Alternatively, one TRP may correspond to the serving cell and the other TRPs may correspond to non-serving cells. In this case, the distances between each TRP and the UE may be different.

[0051] In existing systems, the transmission timing of an uplink (UL) channel and / or an UL signal (UL channel / signal) is adjusted by a timing advance (TA). The reception timing of the UL channel / signal from different user terminals (UE) is adjusted by a radio base station (TRP: Transmission and Reception Point, also referred to as gNodeB: gNB) side.

[0052] The UE may control the timing of UL transmission by applying timing advance (multiple timing advances) for each pre-configured timing advance group (TAG).

[0053] When multiple timing advances are applied, Timing Advance Groups (TAGs) classified by transmission timing are supported. The UE may control the UL transmission timing for each TAG assuming that the same TA offset (or TA value) is applied to each TAG. In other words, the TA offset may be set independently for each TAG.

[0054] When multiple timing advance is applied, the UE independently adjusts the transmission timing of cells belonging to each TAG, so that even when multiple cells are used, the radio base station can synchronize the reception timing of uplink signals from the UE.

[0055] TAGs (e.g., serving cells belonging to the same TAG) may be configured by higher layer parameters. The same timing advance value may be applied to serving cells (e.g., serving cells for which UL is configured) belonging to the same TAG. A timing advance group including the SpCell of a MAC entity may be called a Primary Timing Advance Group (PTAG), and other TAGs may be called Secondary Timing Advance Groups (STAGs). In addition, the maximum number of TAGs may be X (e.g., X=4) per cell group (e.g., MCG / SCG).

[0056] In existing systems (e.g., Rel. 16 NR), the configuration of up to four TAGs per cell group (e.g., MCG / SCG) is supported (see Figure 6). Figure 6 shows a case where three TAGs are configured for a cell group including SpCell and SCell #1 to #4. Here, the SpCell and SCell #1 belong to the first TAG (PTAG or TAG #0), SCell #2 and SCell #3 belong to the second TAG (TAG #1), and SCell #4 belongs to the third TAG (TAG #2).

[0057] A timing advance command (TA command) may be notified to the UE using a MAC control element (e.g., MAC CE). The TA command indicates a transmission timing value of an uplink channel and is included in the MAC control element. The TA command (TAC) is signaled from the radio base station to the UE at the MAC layer. The UE controls a predetermined timer (e.g., a TA timer) based on the reception of the TA command.

[0058] The MAC CE for the timing advance command may include a field for a timing advance group index (e.g., TAG ID) and a field for the timing advance command (see FIG. 7). The MAC CE may be configured by one octet (=8 bits).

[0059] The TAG ID field (TAG ID field) may be configured with, for example, 2 bits. The TAG ID field may be used to indicate the TAG ID of the addressed TAG. The Timing Advance Command field (TAC field) may be configured with, for example, 6 bits. The TAC field contains an index value T that is used to control the amount / value (relative amount / relative value) of timing adjustment that the MAC entity must apply. Ａ (0, 1, 2...63). The MAC CE for the timing advance command shown in Figure 7 may be called a TAC MAC CE.

[0060] FIG. 8 illustrates another example of a MAC CE for a timing advance command. The MAC CE illustrated in FIG. 8 may be referred to as an absolute TAC MAC CE. The MAC CE may be configured with two octets (16 bits). Specifically, the MAC CE may include a field for reserved bits (R-bit field) and a field for a timing advance command (TAC field). The R-bit field (R=0) may be configured with, for example, 4 bits. The TAC field may be configured with, for example, 12 bits across two octets. The TAC field in FIG. 8 may indicate an index value used to control the actual amount / value (absolute amount / value) of TA that the MAC entity must apply, as in FIG. 7. Furthermore, the absolute TAC MAC CE may not include the TAG ID field illustrated in FIG. 7.

[0061] The MAC CE shown in Fig. 7 may be used after initial access is established. On the other hand, the MAC CE shown in Fig. 8 is used only during initial access and may be included in the RAR, etc. Each field included in the MAC CE for the timing advance command described above may be called a TA-related field. Among them, the TAC field shown in Fig. 7 may be called a TA adjustment field / field for instructing TA adjustment / field related to TA adjustment, and the TAC field shown in Fig. 8 may be called an absolute TAC field / field for instructing absolute TAC.

[0062] (Control of UL Transmission Based on Timing Advance) In future wireless communication systems, it is also assumed that in inter-cell mobility, UL transmission will be controlled based on timing advance for a serving cell (or a TRP of a serving cell) and a non-serving cell / additional cell (or a TRP of a non-serving cell / additional cell). Alternatively, in future wireless communication systems, it is also assumed that different TAGs (or TAG-IDs) will be set for one or more TRPs (e.g., multiple TRPs having different PCIs) corresponding to a certain cell (or CC). Alternatively, it is also assumed that different TRPs corresponding to a certain cell will share a common TAG.

[0063] FIG. 9 is a diagram showing an example of TAG settings for multiple cells (or TRPs) with different PCIs.

[0064] It is also assumed that up to M PCIs (e.g., a serving cell plus candidate cells associated with the serving cell) can be configured for each CC, and that up to N TAGs (e.g., N≦M) can be configured for the M PCIs. In this case, one or more PCIs may be associated with one TAG.

[0065] Furthermore, one or more PCIs may be associated with one TAG for up to S serving cells in a cell group (or for up to S serving cells). In this case, up to T TAGs may be configured considering one PCI per CC (Case 1). That is, up to T×N TAGs may be configured for up to M×S cells. Alternatively, up to U TAGs may be configured for up to M×S cells (Case 2).

[0066] In this way, when candidate cells are configured / applied / supported, it is assumed that different serving cells / different candidate cells are associated with the same TAG. The TAG of the candidate cell may be indicated by the base station or may be determined based on the TA of the candidate cell acquired by the UE.

[0067] (Maintenance of Uplink Time Alignment) Parameters such as a time alignment timer (e.g., timeAlignmentTimer) may be configured for the maintenance of UL time alignment. The time alignment timer (per TAG) may control the time at which the MAC entity considers the serving cells belonging to the associated TAG to be UL time aligned.

[0068] Parameters corresponding to each TAG ID may be set by higher layer parameters. For example, a parameter such as a time alignment timer (e.g., timeAlignmentTimer) corresponding to each TAG ID may be set. Alternatively, the TAG ID for each serving cell may be set by higher layer parameters (e.g., tag-ID included in ServingCellConfig). Note that after being set by higher layer parameters, the TAG ID / parameter may be updated by MAC CE.

[0069] A time alignment timer may be maintained for UL time alignment. In Rel. 17, the time alignment timer may be configured / associated per TAG. When the UE receives a MAC CE for a timing advance command (e.g., TAC MAC CE), it starts or restarts the time alignment timer associated with the indicated timing advance group (e.g., TAG), respectively.

[0070] The MAC entity receives a MAC CE for a timing advance command and synchronizes the MAC CE with the indicated TAG by a predetermined value (N ＴＡ ) is maintained, apply a timing advance command for the indicated TAG and start or restart the time alignment timer associated with the indicated TAG. ＴＡ ) may be the timing advance between DL and UL.

[0071] When a timing advance command is received in an RAR message for a serving cell belonging to a TAG (e.g., a TAG of an SpCell) or in a message B (e.g., MSGB) for the SpCell, if the MAC entity does not select a random access preamble from among the collision-based random access preambles, it may apply the timing advance command for that TAG and may also start or restart the time alignment timer associated with that TAG.

[0072] The timing advance command of the PTAG may be applied if an absolute timing advance command (e.g., Absolute Timing Advance Command) is received in response to transmitting a message A (e.g., MSGA) containing a given RNTI MAC CE (e.g., C-RNTI MAC CE).

[0073] The behavior when the time alignment timer expires may be defined separately for the PTAG and the STAG. Note that the timing advance group (TAG) including the SpCell of the MAC entity may be called the primary timing advance group (PTAG), and the other TAGs may be called secondary timing advance groups (STAGs).

[0074] For example, Rel. 17 supports that when a timing advance timer corresponding to a PTAG expires, a predetermined PTAG action is applied, and when a timing advance timer corresponding to a STAG expires, a predetermined STAG action is applied.

[0075] For example, when the time alignment timer expires, the following actions (e.g., predetermined PTAG action / predetermined STAG action) may be performed.

[0076] Actions for a given PTAG If a time alignment timer is associated with a PTAG: Flush all HARQ buffers for all serving cells. Inform RRC to release PUCCH for all serving cells, if configured. Inform RRC to release SRS, if configured. Clear all configured DL allocations and configured UL allocations. Clear PUSCH resources for semi-persistent CSI reporting. Allow all running time alignment timers to expire. Clear N for all TAGs. ＴＡ Maintain.

[0077] Actions for a given STAG: If a time alignment timer is associated with a STAG, then for all serving cells belonging to that TAG: Flush all HARQ buffers. Inform RRC to release PUCCH, if configured. Inform RRC to release SRS, if configured. Clear all configured DL and UL allocations. Clear PUSCH resources for semi-persistent CSI reporting. Clear N for that TAG. ＴＡ Maintain.

[0078] (TA Acquisition) It is also possible that the UE performs UL transmission of a candidate cell in consideration of the TA corresponding to the candidate cell. When considering the TA of the candidate cell, the UE needs to acquire the TA of the candidate cell (for example, TA acquisition of candidate cells).

[0079] For TA acquisition of a candidate cell, several TA acquisition methods are possible, such as TA acquisition using RACH (e.g., RACH-based solutions) and TA acquisition without using RACH (RACH-less solutions). For TA acquisition using RACH, a method with RAR monitoring and a method without RAR monitoring may be supported. The TA acquisition method may be interpreted as a TA acquisition scheme, a TA acquisition type, or a TA acquisition procedure. In the present disclosure, TA acquisition, TA measurement, TA calculation, TA computation, and TA determination may be interpreted as interchangeable terms.

[0080] For example, the UE may acquire the TA of a candidate cell by transmitting a RACH (e.g., a PDCCH ordered RACH) indicated / triggered by the PDCCH to the candidate cell. Information about the TA of the candidate cell (e.g., a TA value) may be included in a response signal (e.g., an RAR) of the RACH. The RAR may be transmitted from the serving cell or the candidate cell. Alternatively, the TA of the candidate cell may be acquired using a RACH triggered by the UE or a RACH triggered by a higher layer from the network. The PDCCH order may be triggered only by the source cell (or the serving cell).

[0081] Alternatively, the UE may acquire the TA of the candidate cell by transmitting a signal other than the RACH to the candidate cell. Information about the TA of the candidate cell (e.g., the TA value) may be indicated to the UE from the base station. As the signal other than the RACH, for example, the SRS may be applied (e.g., SRS-based TA measurement).

[0082] Alternatively, the UE may measure / calculate / obtain the TA for the candidate cell based on DL signals (e.g., downlink reference signals) transmitted from each cell (e.g., candidate cell / serving cell). A method in which the UE obtains the TA for the candidate cell based on DL signals transmitted from one or more cells may be called UE-based TA measurement.

[0083] In the UE-based TA measurement, the downlink reference signal may be a predetermined DL signal (e.g., a synchronization signal block (e.g., SSB) / CSI-RS, etc.). For example, the UE may measure the difference / difference in reception timing of DL signals from multiple cells (or two cells) and obtain the TA of the candidate cell.

[0084] The multiple cells may include a reference cell (e.g., a serving cell). In this case, the UE may calculate the TA required for the candidate cell based on the reception timing of the reference cell (and the TA value of the reference cell) and the timing difference (e.g., T) between the reference cell and the candidate cell. The UE may obtain the TA of the candidate cell using a timing advance command (TAC) transmitted from the serving cell.

[0085] Fig. 10 is a diagram showing an example of a cell switching operation when UE-based TA measurement is configured / supported. Note that the operation shown in Fig. 10 is an example, and the present embodiment is not limited to this.

[0086] The source cell may transmit information about the configuration of candidate cells (e.g., candidate cell configuration information) to the UE. The information about the configuration of candidate cells may be configured by a predetermined higher layer parameter (e.g., LTM-CandidateConfig). The information about the configuration of candidate cells may include information about TA acquisition applied to each candidate cell. For example, the information about candidate cells for which UE-based TA measurements are configured may be included.

[0087] The source cell may send information / signaling to the UE to trigger / instruct UE-based TA measurements, which may be triggered by MAC CE / DCI.

[0088] When the UE receives information / signaling triggering / instructing UE-based TA measurement, the UE may measure the difference / difference in the reception timing of DL signals from multiple cells (or two cells) to obtain the TA of the candidate cell. For example, the UE may measure / calculate the difference / difference in the reception timing of DL signals between a reference cell (or a reference cell) and a candidate cell. Information about the reference cell / candidate cell may be indicated to the UE. As an example, the reference cell may be a source cell (or a serving cell).

[0089] When a reference cell (e.g., a source cell / a serving cell / a specific candidate cell) and a candidate cell are not synchronized, the UE may apply a predetermined offset parameter when acquiring the TA between the reference cell and the candidate cell. The predetermined offset parameter may be configured in the UE by a higher layer configuration (e.g., an RRC configuration).

[0090] Note that the source cell may not transmit information / signaling to trigger / instruct the UE-based TA measurement to the UE, in which case the UE may autonomously perform the UE-based TA measurement based on higher layer parameters that instruct the configuration of the UE-based TA measurement.

[0091] When the UE acquires the TA based on the UE-based TA measurement, the UE may transmit predetermined signaling (or information) to the source cell (or reference cell) / target cell (or candidate cell).

[0092] The predetermined signaling (or information) may be applied to determining / notifying the reliability (or validity / appropriateness) of the TA obtained by the UE-based TA measurement. For example, when the validity of the TA obtained by the UE-based TA measurement is determined based on other conditions / rules, the reliability (or whether it is valid or not) of the TA may be notified by the predetermined signaling (or information).

[0093] The UE / network (or base station) may determine / notify the reliability (or validity / appropriateness) of the TA acquired by the UE-based TA measurement based on predetermined signaling. The predetermined signaling (or information) may be transmitted using MAC CE / UCI / PUCCH / PUSCH.

[0094] It should be noted that the predetermined signaling (or information) may not be transmitted.

[0095] Next, the source cell may transmit a cell switch command to the UE. TA information (e.g., information on the validity / appropriateness of the TA acquired by the UE-based TA measurement) may be transferred / notified from the source cell to the target cell. After the cell switch, the UE may control UL transmission based on the TA acquired by the UE-based TA measurement that is determined to be valid / appropriate.

[0096] (Analysis) Rel. 18 is expected to support two types of LTM: RACH-based LTM, in which a random access procedure is applied after a UE receives a MAC CE instructing a cell switch (e.g., an LTM Cell Switch Command MAC CE), and RACH-less LTM, in which no random access procedure is performed.

[0097] For example, whether or not the random access procedure is to be applied may be indicated based on the value of a predetermined field (for example, a timing advance command (TAC) field) included in a cell switch command MAC CE that instructs a cell switch.

[0098] For example, if the value of the TAC field of the cell switch command MAC CE is not set to a specific value (e.g., FFF), the UE may skip the RACH procedure (e.g., PRACH transmission) for the target cell after receiving the cell switch command MAC CE (perform a RACH-less LTM cell switch). In this case, the UE may determine the timing advance for the target cell based on the value of the TAC field. Note that the specific value (e.g., FFF) may mean that all 12 bits of the TAC field are 1 (or that the TA of the target cell is not included).

[0099] On the other hand, if the value of the TAC field of the cell switch command MAC CE is a specific value, the UE may be controlled to perform a RACH procedure (e.g., PRACH transmission) for the target cell indicated by the cell switch command MAC CE. That is, triggering of a random access procedure for an LTM cell switch is instructed based on the value of the field included in the cell switch command MAC CE.

[0100] As described above, as a method for acquiring the TA of a candidate cell, UE-based TA measurement (e.g., UE-based TA measurement) that does not use a random access (RACH) procedure is supported. When UE-based TA measurement is applied, the network (e.g., base station) provides / configures an RRC parameter (e.g., ueMeasuredTA) for configuring UE-based TA measurement to the UE.

[0101] When a higher layer parameter (e.g., ueMeasuredTA) for configuring UE-based TA measurement is provided, the UE controls to apply UE-based TA measurement to acquire the TA of the candidate cell.

[0102] However, when UE-based TA measurement is applied (e.g., ueMeasuredTA is provided to the UE), there may be a case where only the UE has (or recognizes) the TA of the candidate cell when the UE receives the cell switch command MAC CE. In such a case, it is desirable to trigger RACH-less LTM from the viewpoint of shortening the interruption time (e.g., interruption time).

[0103] However, since the base station cannot recognize that the UE has a TA of the candidate cell, it is possible that the cell switch command MAC CE triggers the RACH-based LTM, which may result in unnecessary procedures (e.g., RACH procedures) and delays even if the UE has a TA of the candidate cell, triggering the RACH-based LTM (and not the RACH-less LTM) by the cell switch command MAC CE.

[0104] Therefore, the present inventors have studied the LTM procedure when RACH-less LTM is set in LTM in which RACH-based and RACH-less are supported, and have conceived one aspect of the present embodiment.

[0105] (Various Replacements, etc.) Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. Wireless communication methods according to the embodiments may be applied independently or in combination.

[0106] In the present disclosure, "A / B" and "at least one of A and B" may be interpreted interchangeably. Also, in the present disclosure, "A / B / C" may mean "at least one of A, B, and C."

[0107] In the present disclosure, terms such as notify, activate, deactivate, indicate (or indicate), select, configure, update, and determine may be read interchangeably. In the present disclosure, terms such as support, control, controllable, operate, and operate may be read interchangeably.

[0108] In the present disclosure, Radio Resource Control (RRC), RRC parameters, RRC messages, higher layer parameters, fields, information elements (IEs), settings, etc. may be interchangeable. In the present disclosure, Medium Access Control (MAC) control elements (CEs), update commands, activation / deactivation commands, etc. may be interchangeable.

[0109] In the present disclosure, the higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, other messages (e.g., messages from the core network such as positioning protocol (e.g., NR Positioning Protocol A (NRPPa) / LTE Positioning Protocol (LPP)) messages), or a combination thereof.

[0110] In the present disclosure, MAC signaling may use, for example, a MAC Control Element (MAC CE), a MAC Protocol Data Unit (PDU), etc. Broadcast information may be, for example, a Master Information Block (MIB), a System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

[0111] In the present disclosure, physical layer signaling may be, for example, Downlink Control Information (DCI), Uplink Control Information (UCI), and the like.

[0112] In the present disclosure, the terms index, identifier (ID), indicator, resource ID, etc. may be interchangeable. In the present disclosure, the terms sequence, list, set, group, cluster, subset, etc. may be interchangeable.

[0113] In the present disclosure, the terms panel, UE panel, panel group, beam, beam group, precoder, Uplink (UL) transmitting entity, Transmission / Reception Point (TRP), base station, Spatial Relation Information (SRI), spatial relation, SRS Resource Indicator (SRI), Control Resource Set (CORESET), Physical Downlink Shared Channel (PDSCH), Codeword (CW), Transport Block (TB), Reference Signal (RS), antenna port (e.g., Demodulation Reference Signal (DMRS) port), antenna port group (e.g., DMRS port group), group (e.g., spatial relation group, Code Division Multiplexing (CDM) group, reference signal group, CORESET group, Physical Uplink Control Channel (PUCCH) group, PUCCH resource group), resource (e.g., reference signal resource, SRS resource), resource set (e.g., reference signal resource set), CORESET pool, downlink Transmission Configuration Indication state (TCI state) (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, common TCI state, Quasi-Co-Location (QCL), QCL assumption, etc. may be read as interchangeable.

[0114] In the present disclosure, base station, gNB, and network (NW) may be read interchangeably.

[0115] In the present disclosure, a cell group, a serving cell group, a master cell group (MCG), and a secondary cell group (SCG) may be interchangeable. L1 / L2, L1 / L2 signaling, and DCI / MAC CE may be interchangeable. A serving cell may be replaced with a cell that transmits a PDSCH. A candidate cell may refer to a cell that is a candidate to become a serving cell through L1 / L2 inter-cell mobility. L1L2-triggered mobility (LTM) and L1 / L2 inter-cell mobility may be interchangeable.

[0116] In the present disclosure, the terms cell, PCI, serving cell, source serving cell, source cell, CC, BWP, BWP within a CC, and band may be interchangeable. In the present disclosure, the terms cell, PCI, cell with an additional PCI, additional cell, other cell, non-serving cell, cell with a different PCI, candidate cell, candidate serving cell, cell with a PCI different from the PCI of the current serving cell, another serving cell, and target cell may be interchangeable. The target cell may be a cell selected from multiple candidate cells. In the present disclosure, the terms switch, change, and update may be interchangeable. The serving cell may be interchangeable with the serving cell before the switch or the serving cell after the switch.

[0117] In the present disclosure, a potential cell switch command and a request / instruction for a potential cell switch command may be interchangeable. The cell switch command in the present disclosure may be transmitted from a network to a user equipment (UE) by using layer 1 / layer 2 (DCI / MAC CE).

[0118] (Wireless Communication Method) <First Embodiment> The first embodiment relates to an example of an LTM procedure in which an RRC parameter (for example, ueMeasuredTA) for configuring UE-based TA measurements is provided to a UE.

[0119] The UE may determine whether to apply a random access procedure (e.g., whether to apply RACH-less LTM or RACH-based LTM) to the target cell after receiving control information instructing a cell switch (e.g., cell switch command MAC CE) based on a predetermined condition / predetermined value.

[0120] Fig. 11 is a diagram illustrating an example of the LTM procedure in the first embodiment. The applicable LTM procedure is not limited to that illustrated in Fig. 11, and some steps may be omitted, the order of the steps may be reversed, or other steps (e.g., DL / UL early synchronization, L1 measurement reporting, etc.) may be added.

[0121] The UE may receive information about one or more candidate cells and information about the TA acquisition method of the candidate cells (e.g., RRC parameters). The TA acquisition method may be set separately for each candidate cell, or may be set commonly for multiple candidate cells (e.g., a candidate cell group). Here, a case where UE-based TA measurement (ueMeasuredTA) is set as the TA acquisition method is shown.

[0122] When UE-based TA measurement is configured for a certain candidate cell, the UE may control the UE to acquire the TA for the candidate cell by the UE-based TA measurement. Although Fig. 11 shows a case where the TA is acquired by the UE-based TA measurement before receiving the cell switch command MAC CE, the timing of TA acquisition is not limited to this.

[0123] When the UE receives the cell switch command MAC CE, the UE controls to perform mobility / cell switch for the candidate cell (or target cell) indicated by the cell switch command MAC CE. In this case, whether or not to apply the random access procedure to the target cell after receiving the cell switch command MAC CE may be determined based on a predetermined condition / predetermined value.

[0124] The predetermined condition / predetermined value may be at least one of the value of a predetermined field (e.g., timing advance command field) included in the cell switch command MAC CE, whether a predetermined RRC parameter (e.g., ueMeasuredTA / earlyULsync) is set for the UE, the timing at which the UE triggers / starts UE-based TA measurement, and whether the UE executes / finishes TA acquisition through UE-based TA measurement.

[0125] When an RRC parameter (e.g., ueMeasuredTA) that configures UE-based TA measurement is provided to the UE, at least one of the following options 1-1 to 1-5 may be applied.

[0126] [Option 1-1] Based on the RRC parameters (e.g., ueMeasuredTA) used to configure the UE-based TA measurement, the UE may determine whether to apply the random access procedure after receiving the cell switch command MAC CE (or whether to apply RACH-less LTM or RACH-based LTM).

[0127] For example, if ueMeasuredTA is provided, the UE may determine that RACH-less LTM is always triggered, in which case the UE may perform a cell switch to the new target cell (e.g., UL transmission to the new target cell) without performing a random access procedure after receiving the cell switch command MAC CE.

[0128] This makes it possible to trigger RACH-less LTM even when TA acquisition is performed by UE-based TA measurement and the network (e.g., base station) does not know the TA acquired by the UE.

[0129] [Option 1-2] Based on the RRC parameter (e.g., ueMeasuredTA) used for setting the UE-based TA measurement and the value of the timing advance command field (e.g., Timing Advance Command value) included in the cell switch command MAC CE, the UE may determine whether to apply the random access procedure after receiving the cell switch command MAC CE (or whether to apply the RACH-less LTM or the RACH-based LTM).

[0130] For example, if ueMeasuredTA is provided and the value of the timing advance command field included in the cell switch command MAC CE is not set to a specific value (e.g., FFF), the UE may determine that RACH-less LTM is triggered.

[0131] Option 1-2 may be based on the premise that the network (e.g., base station) knows that the UE has performed UE-based TA measurements for the target cell (i.e., the UE has the TA of the target cell). The network may know that the UE has the TA of the target cell based on a report from the UE that includes the TA value / index of the candidate cell.

[0132] This makes it possible to trigger RACH-less LTM by a cell switch command MAC CE when TA acquisition is performed by UE-based TA measurement.

[0133] [Option 1-3] Based on the RRC parameters (e.g., ueMeasuredTA) used for configuring the UE-based TA measurement and the explicit instruction included in the cell switch command MAC CE, the UE may determine whether to apply the random access procedure after receiving the cell switch command MAC CE (or whether to apply RACH-less LTM or RACH-based LTM).

[0134] The explicit instruction may be indicated by the value of a predetermined field (e.g., a reserved field (or an R bit)) included in the cell switch command MAC CE. For example, if the reserved field (or the R bit) is "0", the RACH-based LTM may be indicated / triggered, and if the reserved field (or the R bit) is "1", the RACH-less LTM may be indicated / triggered.

[0135] For example, if ueMeasuredTA is provided and the value of a predetermined field in the cell switch command MAC CE is a specific value (for example, the reserved field (or R bit) is "1"), the UE may determine that RACH-less LTM is triggered.

[0136] Options 1-3 may be based on the assumption that the network (e.g., base station) knows that the UE has performed UE-based TA measurements for the target cell (i.e., the UE has the TA of the target cell). The network may know that the UE has the TA of the target cell based on a report from the UE that includes the index of the candidate cell.

[0137] This makes it possible to trigger RACH-less LTM by a cell switch command MAC CE when TA acquisition is performed by UE-based TA measurement.

[0138] [Options 1-4] Based on the RRC parameters (e.g., ueMeasuredTA) used to configure the UE-based TA measurement and whether the UE has the TA of the target cell, the UE may determine whether to apply the random access procedure (or whether to apply RACH-less LTM or RACH-based LTM) after receiving the cell switch command MAC CE.

[0139] For example, if ueMeasuredTA is provided and the UE has a TA of the target cell, the UE may determine that RACH-less LTM is triggered. If ueMeasuredTA is provided and the UE has a TA of the target cell, the UE may determine that RACH-less LTM is triggered even if the value of the Timing Advance Command field included in the Cell Switch Command MAC CE is set to a specific value (e.g., FFF).

[0140] This makes it possible to trigger RACH-less LTM even when the network (e.g., base station) does not know the TA acquired by the UE when TA acquisition is performed by UE-based TA measurement. Also, even when ueMeasuredTA is provided, if the UE has not acquired the TA when receiving the cell switch command MAC CE, RACH-based LTM can be applied.

[0141] [Option 1-5] When an RRC parameter (e.g., ueMeasuredTA) used for configuring UE-based TA measurements is provided and the value of the Timing Advance Command field included in the cell switch command MAC CE is set to a specific value (e.g., FFF), whether to apply a random access procedure (or whether to apply RACH-less LTM or RACH-based LTM) after receiving the cell switch command MAC CE may be up to the UE (or may be determined by the UE based on predetermined conditions).

[0142] For example, if ueMeasuredTA is provided and the value of the Timing Advance Command field included in the Cell Switch Command MAC CE is set to a specific value (e.g., FFF), the UE may perform RACH-less LTM if it has acquired the TA of the target cell, and may perform RACH-based LTM otherwise.

[0143] If ueMeasuredTA is provided and the value of the Timing Advance Command field included in the cell switch command MAC CE is set to a specific value (e.g., FFF), the UE may perform RACH-less LTM if the MAC CE for TCI state activation for the corresponding target cell is sent before the cell switch command MAC CE, and may perform RACH-based LTM otherwise.

[0144] In Option 1-1 to Option 1-5, the RRC parameters (e.g., ueMeasuredTA) used to configure the UE-based TA measurement may be provided for each cell / UE / frequency / CC. The UE may determine whether to apply RACH-less LTM or RACH-based LTM based on the unit (e.g., each cell / UE / frequency / CC) for which ueMeasuredTA is provided.

[0145] [Variations] In at least one of options 1-1 to 1-5, when RACH-less LTM is triggered, it is also possible that the UE has already acquired a TA by UE-based TA measurement before receiving a cell switch command MAC CE, and the TA is indicated by the cell switch command MAC CE (e.g., TAC field). In this case, the UE may control UL transmission based on at least one of the TA acquired by UE-based TA measurement and the TA indicated by the cell switch command MAC CE (e.g., TAC field).

[0146] For example, the UE may use the TA acquired by UE-based TA measurement to control the transmission timing of the first UL transmission after receiving a cell switch command MAC CE. In this case, the TA indicated by the cell switch MAC CE may not be applied (or may be ignored).

[0147] Alternatively, the UE may use the TA indicated by the cell switch MAC CE to control the transmission timing of the first UL transmission after receiving the cell switch command MAC CE. In this case, the TA obtained by the UE-based TA measurement may not be applied (or may be ignored).

[0148] Second Embodiment The second embodiment relates to an example of a UE operation when RACH-based LTM / RACH-less LTM is triggered. The second embodiment may be applied in combination with the first embodiment (at least one of Option 1-1 to Option 1-5).

[0149] [RACH-based LTM is Triggered] When the RACH-based LTM is triggered (or when the UE determines that the RACH-based LTM has been triggered), at least one of the following UE actions 2-1 to 2-4 may be applied.

[0150] <<UE Operation 2-1>> The UE may transmit a PRACH to the target cell, and can determine the target cell for performing the random access procedure based on the cell switch command MAC CE.

[0151] The synchronization signal block (SSB) used for PRACH transmission to the target cell may be an SSB associated with the TCI state ID for the target cell indicated by the cell switch command MAC CE.

[0152] <<UE Operation 2-2>> The UE may stop communication with the serving cell (previous serving cell). For example, when the RACH-based LTM is triggered, the UE may transmit a PRACH to the target cell of the cell switch destination (UE Operation 2-1) and may control the UE to stop communication with the serving cell of the cell switch source.

[0153] <<UE Operation 2-3>> The UE may release the RRC configuration for the serving cell (previous serving cell). For example, when the RACH-based LTM is triggered, the UE may transmit the PRACH to the target cell of the cell switch destination (UE Operation 2-1) and control the UE to release the RRC configuration for the serving cell of the cell switch source.

[0154] <<UE Operation 2-4>> The UE may store the RRC configuration for the serving cell (previous serving cell). For example, when the RACH-based LTM is triggered, the UE may transmit the PRACH to the target cell of the cell switch destination (UE Operation 2-1) and may control the UE to store the RRC configuration for the serving cell of the cell switch source. This makes it possible to omit the RRC configuration operation when communicating with the serving cell again.

[0155] [RACH-less LTM is triggered] When a RACH-less LTM is triggered (or when the UE determines that a RACH-less LTM has been triggered), at least one of the following UE actions 3-1 to 3-6 may be applied.

[0156] <<UE Operation 3-1>> The UE may monitor the PDCCH for the target cell. The UE can determine the target cell for which the PDCCH is to be monitored based on the cell switch command MAC CE.

[0157] <<UE Operation 3-2>> The UE may stop communication with the serving cell (previous serving cell). For example, when RACH-less LTM is triggered, the UE may start PDCCH monitoring for the target cell of the cell switch destination (UE Operation 3-1) and may control to stop communication with the serving cell of the cell switch source.

[0158] <<UE Operation 3-3>> The UE may release the RRC configuration for the serving cell (previous serving cell). For example, when RACH-less LTM is triggered, the UE may start PDCCH monitoring for the target cell of the cell switch destination (UE Operation 3-1) and control to release the RRC configuration for the serving cell of the cell switch source.

[0159] <<UE Operation 3-4>> The UE may store the RRC configuration for the serving cell (previous serving cell). For example, when RACH-less LTM is triggered, the UE may start PDCCH monitoring for the target cell of the cell switch destination (UE Operation 3-1) and may control the UE to store the RRC configuration for the serving cell of the cell switch source. This makes it possible to omit the RRC configuration operation when communicating with the serving cell again.

[0160] <<UE Operation 3-5>> The UE may perform UE-based TA measurement to acquire the TA of the target cell. For example, when the UE receives a cell switch command MAC CE and does not have the TA of the target cell at the timing when the RACH-less LTM is triggered, UE Operation 3-5 may be applied. UE Operation 3-5 may be suitably applied in Option 1-1 of the first embodiment 1. Of course, the application of UE Operation 3-5 is not limited to this.

[0161] <<UE Operation 3-6>> The UE may use the acquired TA value to perform the first UL (e.g., PUSCH / PUCCH / SRS) transmission in an occasion configured by RRC (e.g., a CG (Configure Grant) occasion).

[0162] The UL transmission may be performed after a predetermined time (e.g., X symbols / ms). Cell switch command MAC CE application time / Beam application time / TAC application time may vary depending on the TA acquisition method.

[0163] When TA is acquired by UE-based TA measurement, the application time (e.g., the time from receiving the cell switch command MAC CE to the first UL transmission) may be reduced compared to when TA is acquired by other methods, because the UE already knows the actual TA value (e.g., TTA) to be used for UL transmission. When other TA acquisition methods are used, the UE must use the TA value (e.g., NTA) indicated in the cell switch command MAC CE for calculation.

[0164] The UE may acquire the TA of the candidate cell by UE-based TA measurement before receiving the cell switch command MAC CE, and when RACH-less LTM is triggered and a timing advance is indicated by the cell switch command MAC CE (e.g., the TAC field), the UE may control the first UL transmission using the already acquired TA. In other words, the UE may control not to apply (or ignore) the timing advance indicated by the cell switch command MAC CE. This can shorten the time from receiving the cell switch command MAC CE to the first UL transmission.

[0165] Alternatively, the UE may be controlled to apply the timing advance indicated by the cell switch command MAC CE (for example, not to apply / ignore the TA obtained by UE-based TA measurement).

[0166] <Supplementary Information> [Notification of Information to UE] In the above-described embodiments, any information may be notified to the UE (from a network (NW) (e.g., a base station (BS))) (in other words, reception of any information from the BS by the UE) using physical layer signaling (e.g., DCI), higher layer signaling (e.g., RRC signaling, MAC CE), a specific signal / channel (e.g., PDCCH, PDSCH, reference signal), or a combination thereof.

[0167] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new Logical Channel ID (LCID) in the MAC subheader, which is not defined in existing standards.

[0168] When the notification is made by DCI, the notification may be made by a specific field of the DCI, a Radio Network Temporary Identifier (RNTI) used to scramble Cyclic Redundancy Check (CRC) bits assigned to the DCI, the format of the DCI, etc.

[0169] Furthermore, notification of any information to the UE in the above embodiments may be performed periodically, semi-persistently, or aperiodically.

[0170] [Notification of Information from UE] In the above-described embodiments, notification of any information from the UE (to the NW) (in other words, transmission / report of any information from the UE to the BS) may be performed using physical layer signaling (e.g., UCI), higher layer signaling (e.g., RRC signaling, MAC CE), a specific signal / channel (e.g., PUCCH, PUSCH, PRACH, reference signal), or a combination thereof.

[0171] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new LCID, which is not defined in existing standards, in the MAC subheader.

[0172] If the notification is made by UCI, the notification may be transmitted using PUCCH or PUSCH.

[0173] Furthermore, any information in the above-described embodiments may be notified from the UE periodically, semi-persistently, or aperiodically.

[0174] [Application of Each Embodiment] At least one of the above-described embodiments may be applied when a specific condition is met. The specific condition may be defined in a standard or may be notified to a UE / BS using higher layer signaling / physical layer signaling.

[0175] At least one of the above-described embodiments may be applied only to UEs that have reported or support a specific UE capability. Note that "supporting" and "whether to support" may be interpreted as interchangeable.

[0176] The specific UE capability may indicate at least one of the following: - Supporting specific processing / operation / control / information for at least one of the above embodiments; - Supporting UE-based TA measurements; - Supporting the configuration of UE-based TA measurements and the application of RACH-less LTM.

[0177] Furthermore, the above-mentioned specific UE capability may be a capability that is applied across all frequencies (commonly regardless of frequency), or may be a capability for each frequency (e.g., one or a combination of a cell, a band, a band combination, a BWP, a component carrier, etc.), or may be a capability for each frequency range (e.g., Frequency Range 1 (FR1), FR2, FR3, FR4, FR5, FR2-1, FR2-2), or may be a capability for each subcarrier spacing (SubCarrier Spacing (SCS)), or may be a capability for each Feature Set (FS) or Feature Set Per Component-carrier (FSPC).

[0178] Furthermore, the specific UE capability may be a capability that is applied to all duplexing methods (commonly regardless of the duplexing method), or may be a capability for each duplexing method (e.g., Time Division Duplex (TDD) or Frequency Division Duplex (FDD)).

[0179] Furthermore, at least one of the above-described embodiments may be applied when the UE configures / activates / triggers specific information related to the above-described embodiments (or performs the operations of the above-described embodiments) through higher layer signaling / physical layer signaling. For example, the specific information may be information indicating that a cell switch is enabled by a potential cell switch command, any RRC parameter for a specific release (e.g., Rel. 18 / 19), etc.

[0180] If the UE does not support at least one of the specific UE capabilities or is not configured with the specific information, the UE may apply, for example, the behavior of Rel. 15 / 16 / 17.

[0181] (Supplementary Notes) The following inventions are supplementary notes regarding one embodiment of the present disclosure. [Supplementary Note 1] A terminal having a receiving unit that receives information indicating one or more candidate cells, information related to a timing advance acquisition method for the candidate cells, and cell switch command control information that instructs a cell switch to a specific candidate cell, and a control unit that determines whether to apply a timing advance procedure to the specific candidate cell after receiving the cell switch command control information, based on the information related to the timing advance acquisition method for the candidate cell. [Supplementary Note 2] The terminal according to Supplementary Note 1, wherein, if a terminal-based timing advance measurement is configured for the specific candidate cell, the control unit controls the terminal to perform a cell switch without performing the random access procedure after receiving the cell switch command control information. [Supplementary Note 3] The terminal according to Supplementary Note 1 or Supplementary Note 2, wherein, if a terminal-based timing advance measurement is configured for the specific candidate cell and a predetermined field included in the control information has a specific value, the control unit controls the terminal to perform a cell switch without performing the random access procedure after receiving the cell switch command control information. [Supplementary Note 4] When a terminal-based timing advance measurement is set for the specific candidate cell and the terminal has a timing advance for the specific candidate cell, the control unit controls the terminal to perform a cell switch without performing the random access procedure after receiving the cell switch command control information. The terminal according to any one of Supplementary Note 1 to Supplementary Note 3.

[0182] (Wireless Communication System) The configuration of a wireless communication system according to an embodiment of the present disclosure will be described below. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above embodiments of the present disclosure or a combination thereof.

[0183] 12 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. The wireless communication system 1 (which may be simply referred to as system 1) may be a system that realizes communication using Long Term Evolution (LTE) or 5th generation mobile communication system New Radio (5G NR) specified by the Third Generation Partnership Project (3GPP).

[0184] The wireless communication system 1 may also support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

[0185] In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (Master Node (MN)), and the NR base station (gNB) is the secondary node (Secondary Node (SN)). In NE-DC, the NR base station (gNB) is the MN, and the LTE (E-UTRA) base station (eNB) is the SN.

[0186] The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity in which both the MN and SN are NR base stations (gNBs) (NR-NR Dual Connectivity (NN-DC))).

[0187] The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with a relatively wide coverage, and base stations 12 (12a-12c) that are located within the macrocell C1 and form small cells C2 that are smaller than the macrocell C1. A user terminal 20 may be located within at least one of the cells. The locations and numbers of the cells and user terminals 20 are not limited to the embodiment shown in the figure. Hereinafter, when there is no need to distinguish between the base stations 11 and 12, they will be collectively referred to as base station 10.

[0188] The user terminal 20 may be connected to at least one of the multiple base stations 10. The user terminal 20 may utilize at least one of carrier aggregation (CA) using multiple component carriers (CCs) and dual connectivity (DC).

[0189] Each CC may be included in at least one of a first frequency band (Frequency Range 1 (FR1)) and a second frequency band (Frequency Range 2 (FR2)). The macro cell C1 may be included in FR1, and the small cell C2 may be included in FR2. For example, FR1 may be a frequency band of 6 GHz or less (sub-6 GHz), and FR2 may be a frequency band higher than 24 GHz (above-24 GHz). Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may correspond to a higher frequency band than FR2.

[0190] Furthermore, the user terminal 20 may perform communication using at least one of time division duplex (TDD) and frequency division duplex (FDD) in each CC.

[0191] The multiple base stations 10 may be connected by wire (e.g., optical fiber compliant with the Common Public Radio Interface (CPRI), an X2 interface, etc.) or wirelessly (e.g., NR communication). For example, when NR communication is used as a backhaul between the base stations 11 and 12, the base station 11 corresponding to the upper station may be called an Integrated Access Backhaul (IAB) donor, and the base station 12 corresponding to the relay station (relay) may be called an IAB node.

[0192] The base station 10 may be connected to the core network 30 directly or via another base station 10. The core network 30 may include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), and the like.

[0193] The core network 30 may include network functions (Network Functions (NF)) such as a User Plane Function (UPF), an Access and Mobility management Function (AMF), a Session Management Function (SMF), a Unified Data Management (UDM), an Application Function (AF), a Data Network (DN), a Location Management Function (LMF), and Operation, Administration and Maintenance (Management) (OAM). A single network node may provide multiple functions. Communication with an external network (e.g., the Internet) may also be performed via the DN.

[0194] The user terminal 20 may be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0195] An Orthogonal Frequency Division Multiplexing (OFDM)-based radio access scheme may be used in the wireless communication system 1. For example, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), or the like may be used in at least one of the downlink (DL) and uplink (UL).

[0196] The radio access scheme may also be called a waveform. Note that in the wireless communication system 1, other radio access schemes (e.g., other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the UL and DL radio access schemes.

[0197] In the wireless communication system 1, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20, a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc. may be used as the downlink channel.

[0198] Furthermore, in the wireless communication system 1, an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20, an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), or the like may be used as an uplink channel.

[0199] The PDSCH transmits user data, higher layer control information, a System Information Block (SIB), etc. The PUSCH may transmit user data, higher layer control information, etc. Furthermore, the PBCH may transmit a Master Information Block (MIB).

[0200] Lower layer control information may be transmitted by the PDCCH. The lower layer control information may include, for example, Downlink Control Information (DCI) including scheduling information for at least one of the PDSCH and the PUSCH.

[0201] Note that the DCI for scheduling the PDSCH may be referred to as a DL assignment, a DL DCI, etc., and the DCI for scheduling the PUSCH may be referred to as a UL grant, a UL DCI, etc. Note that the PDSCH may be replaced with DL data, and the PUSCH may be replaced with UL data.

[0202] A control resource set (CORESET) and a search space may be used to detect the PDCCH. The CORESET corresponds to resources for searching for DCI. The search space corresponds to a search region and a search method for PDCCH candidates. One CORESET may be associated with one or more search spaces. The UE may monitor the CORESET associated with a certain search space based on the search space configuration.

[0203] One search space may correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may be referred to as a search space set. Note that the terms "search space," "search space set," "search space configuration," "search space set configuration," "CORESET," "CORESET configuration," and the like in the present disclosure may be read interchangeably.

[0204] The PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), delivery confirmation information (which may be called, for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR). The PRACH may transmit a random access preamble for establishing a connection with a cell.

[0205] In the present disclosure, downlink, uplink, etc. may be expressed without adding "link." Also, various channels may be expressed without adding "Physical" to the beginning.

[0206] In the wireless communication system 1, a synchronization signal (SS), a downlink reference signal (DL-RS), etc. may be transmitted. In the wireless communication system 1, as the DL-RS, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), a phase tracking reference signal (PTRS), etc. may be transmitted.

[0207] The synchronization signal may be, for example, at least one of a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). A signal block including an SS (PSS, SSS) and a PBCH (and a DMRS for the PBCH) may be referred to as an SS / PBCH block, an SS Block (SSB), or the like. Note that the SS, SSB, and the like may also be referred to as a reference signal.

[0208] Furthermore, in the wireless communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), or the like may be transmitted as an uplink reference signal (UL-RS). Note that the DMRS may also be called a user equipment-specific reference signal (UE-specific reference signal).

[0209] (Base Station) Fig. 13 is a diagram showing an example of the configuration of a base station according to an embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission line interface 140. Note that the base station may include one or more of each of the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission line interface 140.

[0210] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the base station 10 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0211] The control unit 110 performs overall control of the base station 10. The control unit 110 can be configured from a controller, a control circuit, and the like that are explained based on common understanding in the technical field to which the present disclosure relates.

[0212] The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may control transmission and reception using the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140, measurement, etc. The control unit 110 may generate data, control information, sequences, etc. to be transmitted as signals, and transfer them to the transceiver unit 120. The control unit 110 may perform call processing (setting up, releasing, etc.) of communication channels, status management of the base station 10, management of radio resources, etc.

[0213] The transceiver unit 120 may include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0214] The transmitting / receiving unit 120 may be configured as an integrated transmitting / receiving unit, or may be configured from a transmitting unit and a receiving unit. The transmitting unit may be configured from a transmission processing unit 1211 and an RF unit 122. The receiving unit may be configured from a reception processing unit 1212, the RF unit 122, and a measurement unit 123.

[0215] The transmitting and receiving antenna 130 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

[0216] The transceiver 120 may transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 120 may receive the above-mentioned uplink channel, uplink reference signal, etc.

[0217] The transceiver 120 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like.

[0218] The transmitter / receiver unit 120 (transmission processing unit 1211) may perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

[0219] The transmitter / receiver unit 120 (transmission processing unit 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0220] The transceiver unit 120 (RF unit 122) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 130.

[0221] On the other hand, the transceiver unit 120 (RF unit 122) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 130.

[0222] The transceiver 120 (reception processing unit 1212) may apply reception processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, thereby acquiring user data, etc.

[0223] The transceiver 120 (measurement unit 123) may perform measurements on the received signal. For example, the measurement unit 123 may perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 110.

[0224] The transmission path interface 140 may transmit and receive signals (backhaul signaling) between devices included in the core network 30 (e.g., network nodes that provide NF), other base stations 10, etc., and may acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

[0225] The transmitting section and receiving section of the base station 10 in the present disclosure may be configured by at least one of the transmitting / receiving section 120, the transmitting / receiving antenna 130, and the transmission path interface 140.

[0226] The transceiver 120 may transmit information indicating one or more candidate cells, information regarding a timing advance acquisition method for the candidate cells, and cell switch command control information instructing a cell switch to a specific candidate cell.

[0227] The control unit 110 may instruct whether or not to apply a timing advance procedure to a specific candidate cell after receiving the cell switch command control information, based on information about a timing advance acquisition method for the candidate cell.

[0228] (User Terminal) Fig. 14 is a diagram showing an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transceiver unit 220, and a transceiver antenna 230. Note that the user terminal 20 may include one or more of each of the control unit 210, the transceiver unit 220, and the transceiver antenna 230.

[0229] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the user terminal 20 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0230] The control unit 210 performs overall control of the user terminal 20. The control unit 210 can be configured from a controller, a control circuit, etc., which are described based on common understanding in the technical field to which the present disclosure relates.

[0231] The control unit 210 may control signal generation, mapping, etc. The control unit 210 may control transmission and reception, measurement, etc. using the transceiver unit 220 and the transceiver antenna 230. The control unit 210 may generate data, control information, sequences, etc. to be transmitted as signals and transfer them to the transceiver unit 220.

[0232] The transceiver unit 220 may include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0233] The transmitting / receiving unit 220 may be configured as an integrated transmitting / receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 2211 and an RF unit 222. The receiving unit may be composed of a reception processing unit 2212, an RF unit 222, and a measurement unit 223.

[0234] The transmitting / receiving antenna 230 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

[0235] The transceiver 220 may receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 220 may transmit the above-mentioned uplink channel, uplink reference signal, etc.

[0236] The transceiver unit 220 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like.

[0237] The transceiver unit 220 (transmission processing unit 2211) may perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

[0238] The transmitter / receiver unit 220 (transmission processing unit 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0239] Whether or not to apply DFT processing may be based on the setting of transform precoding. When transform precoding is enabled for a certain channel (e.g., PUSCH), the transceiver unit 220 (transmission processing unit 2211) may perform DFT processing as the transmission processing to transmit the channel using a DFT-s-OFDM waveform, and if not, it may not be necessary to perform DFT processing as the transmission processing.

[0240] The transceiver unit 220 (RF unit 222) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 230.

[0241] On the other hand, the transceiver unit 220 (RF unit 222) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 230.

[0242] The transceiver unit 220 (reception processing unit 2212) may apply reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, and acquire user data, etc.

[0243] The transceiver 220 (measurement unit 223) may perform measurements on the received signal. For example, the measurement unit 223 may perform RRM measurements, CSI measurements, etc. based on the received signal. The measurement unit 223 may measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 210.

[0244] The measurement unit 223 may derive channel measurements for CSI calculation based on the channel measurement resources. The channel measurement resources may be, for example, non-zero power (NZP) CSI-RS resources. The measurement unit 223 may also derive interference measurements for CSI calculation based on the interference measurement resources. The interference measurement resources may be at least one of an NZP CSI-RS resource for interference measurement, a CSI-Interference Measurement (IM) resource, etc. Note that CSI-IM may be referred to as CSI-Interference Management (IM) or may be interchangeably read as Zero Power (ZP) CSI-RS. Note that in the present disclosure, CSI-RS, NZP CSI-RS, ZP CSI-RS, CSI-IM, CSI-SSB, etc. may be interchangeably read as interchangeable.

[0245] The transmitting unit and receiving unit of the user terminal 20 in the present disclosure may be configured by at least one of the transmitting / receiving unit 220 and the transmitting / receiving antenna 230.

[0246] The transceiver 220 may receive information indicating one or more candidate cells, information regarding a timing advance acquisition method for the candidate cells, and cell switch command control information instructing a cell switch to a specific candidate cell.

[0247] The controller 210 may determine whether to apply a timing advance procedure to a specific candidate cell after receiving the cell switch command control information, based on information about a timing advance acquisition method for the candidate cell.

[0248] When terminal-based timing advance measurement is configured for a specific candidate cell, the control unit 210 may perform control to perform a cell switch without performing a random access procedure after receiving the cell switch command control information.

[0249] When a terminal-based timing advance measurement is set for a specific candidate cell and a specific field included in the control information has a specific value, the control unit may control the cell switch to be performed without performing a random access procedure after receiving the cell switch command control information.

[0250] If a terminal-based timing advance measurement is configured for a specific candidate cell and the terminal has a timing advance for the specific candidate cell, the control unit may control the cell switch to be performed without performing a random access procedure after receiving the cell switch command control information.

[0251] (Hardware Configuration) Note that the block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and 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 (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or the multiple devices.

[0252] Here, the functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, deeming, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission may be called a transmitting unit, transmitter, etc. As described above, the implementation method of each is not particularly limited.

[0253] For example, a base station, a user terminal, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 15 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. The above-described base station 10 and user terminal 20 may be physically 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.

[0254] In the present disclosure, the terms apparatus, circuit, device, section, unit, etc. may be used interchangeably. The hardware configurations of the base station 10 and the user terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0255] For example, although only one processor 1001 is shown, there may be multiple processors. Furthermore, processing may be performed by one processor, or processing may be performed by two or more processors simultaneously, serially, or in other ways. Furthermore, processor 1001 may be implemented by one or more chips.

[0256] Each function in the base station 10 and the user terminal 20 is realized, for example, by loading specified software (programs) onto hardware such as a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication via the communication device 1004, and control at least one of reading and writing data in the memory 1002 and the storage 1003.

[0257] The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, at least a part of the above-mentioned control unit 110 (210), transceiver unit 120 (220), etc. may be realized by the processor 1001.

[0258] 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. For example, the control unit 110 (210) may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and the other functional blocks may be implemented in a similar manner.

[0259] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically EEPROM (EEPROM), Random Access Memory (RAM), or other suitable storage medium. The memory 1002 may also be referred to as a register, cache, main memory, etc. The memory 1002 may store executable programs (program codes), software modules, etc. for implementing a wireless communication method according to an embodiment of the present disclosure.

[0260] Storage 1003 is a computer-readable recording medium and may be composed of at least one of, for example, a flexible disk, a floppy disk, a magneto-optical disk (e.g., a compact disc (e.g., a Compact Disc ROM (CD-ROM)), a digital versatile disc, a Blu-ray disc), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, a stick, a key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as an auxiliary storage device.

[0261] 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 referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the above-mentioned transmission / reception unit 120 (220), transmission / reception antenna 130 (230), etc. may be realized by the communication device 1004. The transmission / reception unit 120 (220) may be implemented as a transmission unit 120a (220a) and a reception unit 120b (220b) that are physically or logically separated.

[0262] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, a light emitting diode (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).

[0263] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by 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.

[0264] Furthermore, the base station 10 and the user terminal 20 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 using this hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0265] (Modifications) Note that terms described in the present disclosure and terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may be interchangeable. A signal may also be a message. A reference signal may be abbreviated as RS, and may also be called a pilot, pilot signal, etc. depending on the applicable standard. A component carrier (CC) may also be called a cell, frequency carrier, carrier frequency, etc.

[0266] A radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting a radio frame may be called a subframe. Furthermore, a subframe may 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.

[0267] Here, the numerology may be a communication parameter applied to at least one of transmission and reception of a signal or channel, and may indicate at least one of, for example, Subcarrier Spacing (SCS), bandwidth, symbol length, cyclic prefix length, Transmission Time Interval (TTI), number of symbols per TTI, radio frame structure, specific filtering performed by a transceiver in the frequency domain, and specific windowing performed by a transceiver in the time domain.

[0268] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may also be a time unit based on numerology.

[0269] A slot may include multiple minislots. Each minislot may consist of one or multiple 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 (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (PUSCH) mapping type B.

[0270] A radio frame, a subframe, a slot, a minislot, and a symbol all represent time units for transmitting signals. The radio frame, the subframe, the slot, the minislot, and the symbol may be referred to by other names corresponding to the radio frame, the subframe, the slot, the minislot, and the symbol. Note that the time units such as a frame, a subframe, a slot, a minislot, and a symbol in the present disclosure may be interchangeable.

[0271] For example, one subframe may be referred to as a TTI, or 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 (for example, 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.

[0272] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. Note that the definition of TTI is not limited to this.

[0273] 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.

[0274] 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. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0275] A TTI having a time length of 1 ms may be called a regular TTI (TTI in 3GPP Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0276] 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 greater than or equal to 1 ms.

[0277] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0278] In addition, an RB may include one or more symbols in the time domain and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may be composed of one or more resource blocks.

[0279] In addition, one or more RBs may be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0280] 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.

[0281] A Bandwidth Part (BWP), which may also be referred to as a partial 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 BWP and numbered within the BWP.

[0282] The BWP may include a UL BWP (BWP for UL) and a DL BWP (BWP for DL). One or more BWPs may be configured for a UE within one carrier.

[0283] 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."

[0284] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. 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, etc. may be changed in various ways.

[0285] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by a predetermined index.

[0286] The names used for parameters and the like in this disclosure are not intended to be limiting in any way. Furthermore, the mathematical expressions and the like using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (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.

[0287] 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.

[0288] Furthermore, information, signals, etc. may be output from a higher layer to a lower layer and / or from a lower layer to a higher layer. Information, signals, etc. may be input / output via multiple network nodes.

[0289] Input and output information, signals, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information, signals, etc. may be overwritten, updated, or added. Output information, signals, etc. may be deleted. Input information, signals, etc. may be transmitted to another device.

[0290] 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 in the present disclosure may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB)), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0291] Note that the physical layer signaling may be referred to as Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), L1 control information (L1 control signal), etc. Furthermore, the RRC signaling may be referred to as an RRC message, such as an RRC Connection Setup message or an RRC Connection Reconfiguration message. Furthermore, the MAC signaling may be notified using, for example, a MAC Control Element (CE).

[0292] Furthermore, notification of specified information (e.g., notification that "it is X") is not limited to explicit notification, but may be made implicitly (e.g., by not notifying the specified information or by notifying other information).

[0293] The determination may be made by a value represented by one bit (0 or 1), by a Boolean value represented by true or false, or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0294] 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.

[0295] 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), these wired and / or wireless technologies are included within the definition of transmission media.

[0296] As used in this disclosure, the terms "system" and "network" may be used interchangeably. A "network" may refer to devices included in the network (e.g., base stations).

[0297] In this disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "layer," "number of layers," "rank," "resource," "resource set," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," "UE panel," "transmitting entity," "receiving entity," etc. may be used interchangeably.

[0298] In the present disclosure, the term "antenna port" may be interchangeably read as an antenna port for any signal / channel (e.g., a demodulation reference signal (DMRS) port). In the present disclosure, the term "resource" may be interchangeably read as a resource for any signal / channel (e.g., a reference signal resource, an SRS resource, etc.). The resource may include time / frequency / code / space / power resources. Furthermore, the spatial domain transmission filter may include at least one of a spatial domain transmission filter and a spatial domain reception filter.

[0299] The group may include, for example, at least one of a spatial relationship group, a Code Division Multiplexing (CDM) group, a Reference Signal (RS) group, a Control Resource Set (CORESET) group, a PUCCH group, an antenna port group (e.g., a DMRS port group), a layer group, a resource group, a beam group, an antenna group, a panel group, and the like.

[0300] In addition, in the present disclosure, beam, SRS Resource Indicator (SRI), CORESET, CORESET pool, PDSCH, PUSCH, codeword (CW), transport block (TB), RS, etc. may be read as interchangeable terms.

[0301] In addition, in the present disclosure, the terms TCI state, downlink TCI state (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, common TCI state, joint TCI state, etc. may be read interchangeably.

[0302] Furthermore, in the present disclosure, terms such as "QCL," "QCL assumption," "QCL relationship," "QCL type information," "QCL property / properties," "specific QCL type (e.g., Type A, Type D) property," and "specific QCL type (e.g., Type A, Type D)" may be interchangeable.

[0303] In the present disclosure, terms such as index, identifier (ID), indicator, indication, and resource ID may be interchangeable. In the present disclosure, terms such as sequence, list, set, group, cluster, and subset may be interchangeable.

[0304] Furthermore, the spatial relationship information identifier (ID) (TCI state ID) and the spatial relationship information (TCI state) may be interchangeable. The "spatial relationship information (TCI state)" may be interchangeable with "set of spatial relationship information (TCI state)", "one or more pieces of spatial relationship information", etc. The TCI state and the TCI may be interchangeable. The spatial relationship information and the spatial relationship may be interchangeable.

[0305] In the present disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNB (eNodeB)," "gNB (gNodeB)," "access point," "transmission point (TP)," "reception point (RP)," "transmission / reception point (TRP)," "panel," "cell," "sector," "cell group," "carrier," "component carrier," etc. may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, picocell, etc.

[0306] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). 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 service within that coverage.

[0307] In the present disclosure, a base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control / operate based on the information.

[0308] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0309] A mobile station may also be referred to 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.

[0310] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a wireless communication device, etc. Note that at least one of the base station and the mobile station may be a device mounted on a moving object, the moving object itself, etc.

[0311] The mobile body is a movable object that can move at any speed and naturally includes cases where the mobile body is stationary. Examples of the mobile body include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones, multicopters, quadcopters, balloons, and objects mounted thereon. The mobile body may also be a mobile body that moves autonomously based on an operation command.

[0312] 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). Note that 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.

[0313] 16 is a diagram showing an example of a vehicle according to an embodiment. The vehicle 40 includes a drive unit 41, a steering unit 42, an accelerator pedal 43, a brake pedal 44, a shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, an electronic control unit 49, various sensors (including a current sensor 50, an RPM sensor 51, an air pressure sensor 52, a vehicle speed sensor 53, an acceleration sensor 54, an accelerator pedal sensor 55, a brake pedal sensor 56, a shift lever sensor 57, and an object detection sensor 58), an information service unit 59, and a communication module 60.

[0314] The drive unit 41 is configured with at least one of an engine, a motor, and a hybrid of an engine and a motor, for example. The steering unit 42 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels 46 and the rear wheels 47 based on the operation of the steering wheel operated by a user.

[0315] The electronic control unit 49 is composed of a microprocessor 61, memory (ROM, RAM) 62, and a communication port (for example, an input / output (IO) port) 63. Signals are input to the electronic control unit 49 from various sensors 50-58 provided in the vehicle. The electronic control unit 49 may also be called an Electronic Control Unit (ECU).

[0316] The signals from the various sensors 50-58 include a current signal from a current sensor 50 that senses the current of the motor, a rotation speed signal of the front wheels 46 / rear wheels 47 obtained by a rotation speed sensor 51, an air pressure signal of the front wheels 46 / rear wheels 47 obtained by an air pressure sensor 52, a vehicle speed signal obtained by a vehicle speed sensor 53, an acceleration signal obtained by an acceleration sensor 54, a depression amount signal of the accelerator pedal 43 obtained by an accelerator pedal sensor 55, a depression amount signal of the brake pedal 44 obtained by a brake pedal sensor 56, an operation signal of the shift lever 45 obtained by a shift lever sensor 57, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 58.

[0317] The information service unit 59 is composed of various devices, such as a car navigation system, an audio system, speakers, a display, a television, and a radio, for providing (outputting) various information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 59 uses information acquired from external devices via the communication module 60 or the like to provide various information / services (e.g., multimedia information / multimedia services) to the occupants of the vehicle 40.

[0318] The information service unit 59 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.

[0319] The driving assistance system unit 64 includes various devices for providing functions to prevent accidents and reduce the driver's driving burden, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., Global Navigation Satellite System (GNSS)), map information (e.g., High Definition (HD) maps, Autonomous Vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Units (IMUs), Inertial Navigation Systems (INSs)), artificial intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 64 also transmits and receives various information via the communication module 60 to realize driving assistance functions or autonomous driving functions.

[0320] The communication module 60 can communicate with the microprocessor 61 and components of the vehicle 40 via the communication port 63. For example, the communication module 60 transmits and receives data (information) via the communication port 63 to and from the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, the microprocessor 61 and memory (ROM, RAM) 62 in the electronic control unit 49, and the various sensors 50-58, which are provided in the vehicle 40.

[0321] The communication module 60 is a communication device that can be controlled by the microprocessor 61 of the electronic control unit 49 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 60 may be located either inside or outside the electronic control unit 49. The external device may be, for example, the base station 10 or the user terminal 20 described above. Furthermore, the communication module 60 may be, for example, at least one of the base station 10 and the user terminal 20 described above (or may function as at least one of the base station 10 and the user terminal 20).

[0322] The communication module 60 may transmit at least one of signals from the above-mentioned various sensors 50-58 input to the electronic control unit 49, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 59 to an external device via wireless communication. The electronic control unit 49, the various sensors 50-58, the information service unit 59, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 60 may include information based on the above-mentioned input.

[0323] The communication module 60 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from an external device and displays it on an information service unit 59 provided in the vehicle. The information service unit 59 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 received by the communication module 60 (or data / information decoded from the PDSCH)).

[0324] Furthermore, the communication module 60 stores various information received from external devices in a memory 62 that can be used by the microprocessor 61. Based on the information stored in the memory 62, the microprocessor 61 may control the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, various sensors 50-58, and the like provided in the vehicle 40.

[0325] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the user terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "sidelink"). For example, terms such as an uplink channel and a downlink channel may be read as a sidelink channel.

[0326] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station 10 may be configured to have the functions of the user terminal 20 described above.

[0327] In the present disclosure, an operation described as being performed by a base station may be performed by its upper node in some cases. It is apparent that in a network including one or more network nodes having a base station, various operations performed for communication with a terminal may be performed by the base station, one or more network nodes other than the base station (such as, but not limited to, a Mobility Management Entity (MME), a Serving-Gateway (S-GW), etc.), or a combination thereof.

[0328] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, the order of the processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. 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.

[0329] Each aspect / embodiment described in the present disclosure may be a technology other than Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG (x is, for example, an integer or decimal number)), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802. The present invention may be applied to systems that use IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable wireless communication methods, or to next-generation systems that are expanded, modified, created, or defined based on these. Furthermore, the present invention may be applied to a combination of multiple systems (e.g., a combination of LTE or LTE-A and 5G).

[0330] 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."

[0331] 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 or that the first element must in some way precede the second element.

[0332] The term "determining" as used in this disclosure may encompass a wide variety of actions. For example, "determining" may be considered to be judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., looking up in a table, database, or another data structure), ascertaining, etc.

[0333] Additionally, "determining" may be considered to be "determining" receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), etc.

[0334] Furthermore, "determination" may be considered to be "determining" resolving, selecting, choosing, establishing, comparing, etc. In other words, "determination" may be considered to be "determining" some kind of action. In the present disclosure, "determination" may be read interchangeably with the above-mentioned actions.

[0335] Furthermore, in this disclosure, "determine / determining" may be interchangeably read as "assume / assuming," "expect / expecting," "consider / considering," etc. Furthermore, in this disclosure, "does not expect to do..." may be interchangeably read as "assumes not to do...."

[0336] In the present disclosure, "expect" may be interchangeably read as "be expected." For example, "expect(s) ..." ("..." may be expressed, for example, as a that clause, a to-infinitive, etc.) may be interchangeably read as "be expected ...." "does not expect ..." may be interchangeably read as "be not expected ...." Furthermore, "An apparatus A is not expected ..." may be interchangeably read as "an apparatus B other than apparatus A does not expect ... from apparatus A" (e.g., if apparatus A is a UE, apparatus B may be a base station).

[0337] The "maximum transmit power" in this disclosure may mean the maximum value of transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0338] As used in this disclosure, 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."

[0339] In this disclosure, when two elements are connected, they may be considered to be "connected" or "coupled" to one another using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy having wavelengths in the radio frequency range, microwave range, light (both visible and invisible) range, etc., as some non-limiting and non-exhaustive examples.

[0340] 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."

[0341] 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.

[0342] 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.

[0343] In the present disclosure, terms such as "less than or equal to," "less than," "greater than," "more than," "equal to," etc. may be interchangeable. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative, as expressions with "i-th" (i is an arbitrary integer) attached (for example, "highest" may be interchangeable with "i-th highest").

[0344] In this disclosure, the terms "of," "for," "regarding," "related to," "associated with," etc. may be read interchangeably.

[0345] In the present disclosure, terms such as "when A, B," "if A, (then) B," "B upon A," "B in response to A," "B based on A," "B during / while A," "B before A," "B at (the same time as) / on A," "B after A," "B since A," and "B until A" may be interchangeable. Note that A, B, and the like herein may be replaced with appropriate expressions such as nouns, gerunds, and regular sentences, depending on the context. Note that the time difference between A and B may be approximately zero (immediately after or immediately before). A time offset may also be applied to the time at which A occurs. For example, "A" may be interchangeable with "before / after a time offset at which A occurs." The time offset (eg, one or more symbols / slots) may be predefined or may be specified by the UE based on signaled information.

[0346] In the present disclosure, timing, time, duration, time instance, any time unit (e.g., slot, subslot, symbol, subframe), period, occasion, resource, etc. may be read interchangeably.

[0347] Although the invention according to the present disclosure has been described in detail above, it is clear to those skilled in the art that the invention according to the present disclosure is not limited to the embodiments described in the present disclosure. The description of the present disclosure is for illustrative purposes only and does not impose any limiting meaning on the invention according to the present disclosure.

Claims

1. A terminal having a receiving unit that receives information indicating one or more candidate cells, information regarding a timing advance acquisition method for the candidate cells, and cell switch command control information that instructs a cell switch to a specific candidate cell, and a control unit that determines whether or not to apply a timing advance procedure to the specific candidate cell after receiving the cell switch command control information based on the information regarding the timing advance acquisition method for the candidate cell.

2. The terminal of claim 1, wherein when terminal-based timing advance measurement is set for the particular candidate cell, the control unit controls the terminal to perform a cell switch without performing the random access procedure after receiving the cell switch command control information.

3. The terminal of claim 1, wherein when a terminal-based timing advance measurement is set for the specific candidate cell and a specific field included in the control information has a specific value, the control unit controls the terminal to perform a cell switch without performing the random access procedure after receiving the cell switch command control information.

4. A terminal as described in claim 1, wherein when a terminal-based timing advance measurement is configured for the particular candidate cell and the terminal has a timing advance for the particular candidate cell, the control unit controls the terminal to perform a cell switch without performing the random access procedure after receiving the cell switch command control information.

5. A wireless communication method for a terminal comprising the steps of: receiving information indicating one or more candidate cells, information regarding a timing advance acquisition method for the candidate cells, and cell switch command control information instructing a cell switch to a specific candidate cell; and determining whether or not to apply a timing advance procedure to the specific candidate cell after receiving the cell switch command control information based on the information regarding the timing advance acquisition method for the candidate cell.

6. A base station having a transmitting unit that transmits information indicating one or more candidate cells, information regarding a timing advance acquisition method for the candidate cells, and cell switch command control information that instructs a cell switch to a specific candidate cell, and a control unit that instructs whether or not to apply a timing advance procedure to the specific candidate cell after receiving the cell switch command control information based on the information regarding the timing advance acquisition method for the candidate cell.

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