Terminals, wireless communication methods, base stations and systems

Abstract

A terminal according to one embodiment of the present disclosure is provided with: a reception unit that receives signaling instructing a terminal-based timing advance measurement for one or more candidate cells; and a control unit that determines at least one of a timing advance acquisition method to be applied to the candidate cell, a start timing of the terminal-based timing advance measurement to be applied to the candidate cell, and a start timing of the terminal-based timing advance measurement to be applied to the candidate cell, on the basis of the signaling and / or the timing advance acquisition method set for the candidate cell.

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) 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., wireless communication systems after Rel. 16 / 5G), it is expected that communications will be controlled based on inter-cell mobility including a non-serving cell, or inter-cell mobility using multiple transmission / reception points (e.g., Multi-TRP (MTRP)). In inter-cell mobility, it is also expected that candidate cells will be set separately from the serving cell, and that switching between the serving cell and the candidate cell will be performed.

[0006] However, when inter-cell mobility (e.g., switching between a serving cell and a candidate cell) is applied, how to control UL transmission (e.g., control of timing advance, etc.) becomes an issue. For example, it is assumed that UE-based TA measurement will be supported as a method for obtaining timing advance in addition to the random access procedure.

[0007] However, when UE-based TA measurement is supported, it is not clear how to acquire the TA. If the timing advance cannot be acquired properly, inter-cell mobility cannot be performed properly, and there is a risk that the quality of communication will deteriorate.

[0008] The present disclosure has been made in consideration of these points, and one of its objectives is to provide a terminal, a wireless communication method, and a base station that are capable of appropriately controlling communications even when UE-based timing advance measurement is supported.

[0009] A terminal according to one aspect of the present disclosure includes a receiving unit that receives signaling instructing terminal-based timing advance measurement for one or more candidate cells, and a control unit that determines at least one of a timing advance acquisition method to be applied to the candidate cell, a start timing of the terminal-based timing advance measurement to be applied to the candidate cell, and a start timing of the terminal-based timing advance measurement to be applied to the candidate cell based on at least one of the signaling and a timing advance acquisition method set for the candidate cell.

[0010] According to one aspect of the present disclosure, communication can be appropriately controlled even when UE-based timing advance measurement is supported.

[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 association between a serving cell and a candidate cell. Figure 3A is a diagram showing a second example of candidate cell configuration option 2. Figure 3B is a diagram showing a third example of candidate cell configuration option 2. Figure 4 is a diagram showing serving cell switch example 1. Figure 5 is a diagram showing serving cell switch example 2. Figure 6 is a diagram showing serving cell switch example 3. Figure 7 is a diagram showing an example of timing advance groups (TAGs) to which cells included in a cell group belong. Figure 8 is a diagram showing an example of a MAC CE for a timing advance command. Figure 9 is a diagram showing another example of a MAC CE for a timing advance command. Figure 10 is a diagram showing an example of TAG configuration when TAG ID association with a candidate cell is supported. Figure 11 is a diagram showing an overview of L1L2-triggered mobility (LTM). FIG. 12 is a diagram showing a PDCCH-instructed RACH (PDCCH ordered RACH) with random access response (RAR) monitoring for a serving cell. FIG. 13 is a diagram showing a PDCCH-instructed RACH (PDCCH ordered RACH) without random access response (RAR) monitoring for a candidate cell. FIG. 14 is a diagram showing DCI format 1_0 CRC-scrambled by C-RNTI. FIG. 15 is a diagram showing an example of start timing of UE-based TA measurement according to the first embodiment. FIG. 16 is a diagram showing another example of start timing of UE-based TA measurement according to the first embodiment. FIG. 17 is a diagram showing another example of start timing of UE-based TA measurement according to the first embodiment. FIG. 18 is a diagram showing another example of start timing of UE-based TA measurement according to the first embodiment. FIGS. 19A and 19B are diagrams showing an example of application timing of the first embodiment / second embodiment according to a third embodiment. FIG. 20 is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment. FIG. 21 is a diagram illustrating an example of the configuration of a base station according to an embodiment.Fig. 22 is a diagram illustrating an example of a configuration of a user terminal according to an embodiment. Fig. 23 is a diagram illustrating an example of a hardware configuration of a base station and a user terminal according to an embodiment. Fig. 24 is a diagram illustrating an example of a vehicle according to an embodiment.

[0012] (TCI, spatial relationship, QCL) In NR, it is considered to control the reception processing (e.g., at least one of reception, demapping, demodulation, and decoding) and transmission processing (e.g., at least one of transmission, mapping, precoding, modulation, and encoding) in a UE of at least one of a signal and a channel (referred to as a signal / channel) based on a transmission configuration indication state (TCI state).

[0013] The TCI state may represent that which is applied to a downlink signal / channel, and the equivalent of the TCI state that is applied to an uplink signal / channel may be expressed as a spatial relation.

[0014] The TCI state is information about the Quasi-Co-Location (QCL) of signals / channels, and may also be called spatial reception parameters, spatial relation information, etc. The TCI state may be configured in the UE for each channel or signal.

[0015] The QCL is an index indicating the statistical properties of signals / channels. For example, if a signal / channel has a QCL relationship with another signal / channel, it may mean that it can be assumed that at least one of a Doppler shift, a Doppler spread, an average delay, a delay spread, and a spatial parameter (e.g., a spatial Rx parameter) is the same between these different signals / channels (i.e., the signals / channels have a QCL with respect to at least one of these).

[0016] The spatial reception parameters may correspond to a reception beam (e.g., a reception analog beam) of the UE, and the beam may be identified based on a spatial QCL. The QCL (or at least one element of the QCL) in the present disclosure may be replaced with sQCL (spatial QCL).

[0017] A plurality of types (QCL types) of QCL may be defined. For example, four QCL types A to D may be provided, each having different parameters (or parameter sets) that can be assumed to be the same. The parameters (which may be referred to as QCL parameters) are as follows: QCL type A (QCL-A): Doppler shift, Doppler spread, mean delay, and delay spread QCL type B (QCL-B): Doppler shift and Doppler spread QCL type C (QCL-C): Doppler shift and mean delay QCL type D (QCL-D): Spatial reception parameters.

[0018] The UE's assumption that a Control Resource Set (CORESET), channel, or reference signal has a specific QCL (e.g., QCL type D) relationship with another CORESET, channel, or reference signal may be referred to as a QCL assumption.

[0019] The UE may determine at least one of a transmit beam (Tx beam) and a receive beam (Rx beam) for a signal / channel based on the TCI condition or QCL assumption of the signal / channel.

[0020] The TCI state may be, for example, information about the QCL between the channel of interest (in other words, the Reference Signal (RS) for that channel) and another signal (e.g., another RS). The TCI state may be set (indicated) by higher layer signaling, physical layer signaling, or a combination thereof.

[0021] The channel / signal to which the TCI state is applied may be called a target channel / reference signal (target channel / RS), or simply a target, and the other signal may be called a reference reference signal (reference RS), a source RS, or simply a reference.

[0022] The channel for which the TCI state or spatial relationship is set (specified) may be, for example, at least one of a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), a physical uplink shared channel (PUSCH), and a physical uplink control channel (PUCCH).

[0023] Furthermore, the RS that has a QCL relationship with the channel may be at least one of, for example, a synchronization signal block (SSB), a channel state information reference signal (CSI-RS), a sounding reference signal (SRS), a tracking CSI-RS (also called a tracking reference signal (TRS)), a QCL detection reference signal (also called a QRS), a demodulation reference signal (DMRS), etc.

[0024] An SSB is a signal block including at least one of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). An SSB may also be referred to as an SS / PBCH block.

[0025] An RS of QCL type X in a TCI state may refer to an RS that has a QCL type X relationship with a certain channel / signal (DMRS), and this RS may be called a QCL source of QCL type X in the TCI state.

[0026] (L1 / L2 Inter-Cell Mobility) As described above, 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. The terms "layer 1 / layer 2" (L1 / L2) and "DCI / Medium Access Control Control Element (MAC CE)" may be interchangeable. 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." The terms "non-serving cell," "cell having a different PCI," and "additional cell" may be interchangeable.

[0027] <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.

[0028] (1) The UE receives from the serving cell the configuration necessary for using radio resources for data transmission and reception, including the SSB configuration for beam measurement of the TRP corresponding to a PCI different from that of the serving cell and the 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 UE-dedicated channels 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).

[0029] 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.

[0030] 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.

[0031] An additional cell is a cell with an additional PCI that is different from the PCI of the serving cell. The UE can receive / transmit UE-dedicated channels from the additional cell. 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 change is required, such as by handover (also called L3 mobility).

[0032] <Scenario 2> In scenario 2, L1 / L2 inter-cell mobility is applied. With L1 / L2 inter-cell mobility, the serving cell can be changed using functions such as beam control without RRC reconfiguration. In other words, transmission and reception with an additional cell is possible without handover. Since handover requires RRC reconnection, which results in a period when data communication is unavailable, by applying L1 / L2 inter-cell mobility that does not require handover, data communication can be continued 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.

[0033] (1) The UE receives SSB configuration for a cell with a different PCI (additional cell) from the serving cell for beam measurement / serving cell change. (2) The UE performs beam measurement for the cell using the different PCI and reports the measurement results to the serving cell. (3) The UE may receive the configuration for the cell with a different PCI (serving 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 or separately from the configuration in (1). (4) Based on the above report, the TCI state of the cell with a different PCI may be activated via L1 / L2 signaling in accordance with 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 reception / transmission using the pre-configured UE-dedicated channel and TCI state.

[0034] 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.

[0035] 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). The UE can receive / transmit UE-dedicated channels / common channels to / from the new serving cell (or target serving cell). The UE may move out of the coverage of the current serving cell (e.g., current serving cell).

[0036] (Setting of Multiple Candidate Cells) FIG. 2 is a diagram showing an example of association between a serving cell and a candidate cell. SpCell #0, SCell #1, or SCell #2 is assumed to be a serving cell. Note that SpCell means a special cell (including a primary cell (PCell) and a primary secondary cell (PSCell)). SCell means a secondary cell. SpCell #0 is associated with candidate cell #0-1, candidate cell #0-2, and candidate cell #0-3. SCell #1 is associated with candidate cell #1-1. SCell #2 is associated with candidate cell #2-1 and #2-2. In this way, one or more candidate cells (candidate serving cells) may be associated with a serving cell.

[0037] Regarding the setting of candidate cells (candidate cells) when changing the serving cell, for example, the following options 1 and 2 are possible.

[0038] <Option 1> As with inter-cell mobility in Rel. 17, the information in ServingCellConfig may include information about multiple candidate cells. In this case, the multiple candidate cells need to share the same PDCCH / PDSCH / UL configuration as the serving cell.

[0039] For example, in Rel. 17 inter-cell mobility, "mimoParam-r17" is added under ServingCellConfig, and PCI setting information is added. mimoParam-r17 may include additionalPCI-ToAddModList-r17, which is an information list of additional SSBs with PCIs different from the PCI of the serving cell. The same settings as the serving cell may be applied to candidate cells (additional cells, cells with additionalPCI), with the exception of some information.

[0040] <Option 2> Multiple candidate cells may be associated with each serving cell by reusing the carrier aggregation (CA) configuration framework, with a complete configuration (e.g., ServingCellConfig) corresponding to each cell. That is, the candidate cells may not share configuration information with the serving cell and may have a separate configuration. The UE is provided with the complete configuration for each candidate cell, allowing it to communicate properly with the candidate cells.

[0041] In the CA configuration framework, an SpCell can be configured for each cell group, and multiple SCells can be added. By reusing the CA framework, a serving cell can be configured for each cell group for L1 / L2 inter-cell mobility, and multiple candidate cells can be configured. Candidate cells can be activated / deactivated by the MAC CE. Candidate cells can be activated / deactivated by activating / deactivating TCI information corresponding to the candidate cells by the MAC CE. This method is considered to be beneficial for reducing the complexity of UE operations.

[0042] 3A is a diagram showing a first example of Option 2 for candidate cell configuration. In the example of Fig. 3A, a common candidate cell pool for cell switching in the MCG / SCG is applied to the candidate cells. In other words, the candidate cells are treated as one pool (group) regardless of frequency band.

[0043] 3B is a diagram showing a second example of the candidate cell configuration option 2. In the example of FIG. 3B, multiple cell groups are configured, and cell group switching is possible by L1 / L2 signaling. Candidate cells are configured for each cell group, and the configuration for each group includes the indices of the corresponding SpCell and SCell.

[0044] (Signaling for Serving Cell Change Indication) Implicit or explicit signaling for serving cell change indication will now be described.

[0045] [Aspect 1] In aspect 1, implicit signaling for a serving cell change indication is described.

[0046] [[Option 1-1]] When a specific control resource set (CORESET) (e.g., at least one of CORESET#0, CORESET of CH5 Type0-CSS, and CORESET of CH6 / CH7 / CH8 CSS) is indicated (activated) by a MAC CE together with one or more TCI states associated with cells of PCIs different from that of the serving cell (when one or more TCI states associated with cells of PCIs different from that of the serving cell are indicated / activated by a MAC CE for a specific CORESET), the UE may determine to change the serving cell to another cell (cell x, a cell with a different PCI). In other words, this activation may implicitly indicate that the serving cell will be changed to another cell.

[0047] In this case, the UE may update beams of other CORESET IDs, other CORESETs using CH6 / CH7 / CH8, or other CORESETs using CSS to the same TCI state as the activated TCI state.

[0048] [[Option 1-2]] When the MAC CE activates / deactivates the TCI states of the PDSCH, if all such TCI states activated by the MAC CE are associated with the same cell x having a PCI different from that of the serving cell, the UE may determine to change the serving cell to another cell (cell x), i.e., this association may implicitly indicate that the serving cell will be changed to another cell.

[0049] In the case where this option applies, if the NW (base station) does not change the serving cell, when the MAC CE activates the TCI state of a PDSCH associated with a cell with a different PCI, it must also include the TCI state related to another cell (e.g., the current serving cell or a second cell with a different PCI).

[0050] [[Options 1-3]] If the MAC CE activates / deactivates unified TCI states (e.g., corresponding to the unified TCI framework in Rel. 17) and all activated unified TCI states are associated with the same cell x with different PCIs, the UE may determine to change the serving cell to another cell (cell x), i.e., this association may implicitly indicate that the serving cell will be changed to another cell.

[0051] [Aspect 2] In aspect 2, explicit signaling for a serving cell change instruction will be described. In aspect 2, for example, the above-mentioned scenario 2 is applied.

[0052] [Option 2-1] An example of a serving cell change instruction will be described below. Note that activation / deactivation of a non-serving cell, change of a serving cell, and transmission / reception with another cell (non-serving cell) having a physical cell ID different from the physical cell ID of the serving cell may be interpreted as interchangeable.

[0053] The UE may receive a new MAC CE including at least one of the fields (information) indicating the following (1) to (3) corresponding to a non-serving cell, which is used for activating / deactivating the non-serving cell. When the UE receives the MAC CE, the UE may determine to change the serving cell to another cell (non-serving cell). Furthermore, the UE may control transmission and reception of DL signals / UL signals with the non-serving cell based on the information. Note that the non-serving cell may be one or multiple. In the example shown below, a MAC CE including multiple fields indicating multiple non-serving cell indexes is applied.

[0054] (1) Serving cell ID, (2) BWP ID, and (3) Non-serving cell ID used for activation. The non-serving cell ID may be replaced with any information corresponding to the non-serving cell (that can identify the non-serving cell).

[0055] As an example of (3), any of (3-1) to (3-5) may be applied. (3-1) PCI (PCI used directly). For example, 10 bits are used. (3-2) Re-creation index (new ID) of non-serving cells. The new ID may be associated with a part of the PCI and configured only for serving and non-serving cells used (available) by the UE. The new ID can reduce the number of bits compared to the PCI. (3-3) CSI reporting configuration ID (CSI-ReportConfigId) (when CSI-ReportConfig corresponds to one or more non-serving cells). (3-4) CSI resource configuration ID (CSI-ResourceConfigId) (when CSI-ResourceConfigId corresponds to one or more non-serving cells). (3-5) Bitmap indicating activation / deactivation of each non-serving cell. The size (number of bits) of the bitmap may be the same as the number of non-serving cells configured on this CC. For example, when activating the second non-serving cell among three non-serving cells, "010" is set.

[0056] At least one of the pieces of information included in the MAC CE may be included in the DCI. Alternatively, at least one of the serving cells activated by the MAC CE may be indicated by the DCI. The MAC CE / DCI may include a field indicating the TCI status / SSB / CSI-RS from a cell having a different PCI so that the UE can recognize the DL beam to monitor on the target cell (post-change serving cell). The UE may create and transmit a beam report (CSI report) using the TCI status / SSB / CSI-RS.

[0057] [[Option 2-2]] The UE may receive a MAC CE in which a new 1-bit field "C" is added to the existing MAC CE. The field indicates whether to change the serving cell. The UE may receive the MAC CE and determine whether to change the serving cell to another cell based on the field.

[0058] [Option 2-3] In addition to the MAC CE in Option 2-2, the MAC CE may further include a field indicating the serving cell index / PCI / other ID (such as the new ID in Option 2-1 above), and a field indicating the TCI state / SSB / CSI-RS of the target cell (the serving cell after the change).

[0059] In this way, since the instruction for the serving cell change instruction is indicated by the MAC CE / DCI, the UE can appropriately change the serving cell.

[0060] [Serving Cell Switch Example 1] Figure 4 is a diagram showing Serving Cell Switch Example 1. For example, in a serving cell SpCell #0 of an MCG / SCG, if an instruction to change the serving cell to candidate cell #0-2 is given by L1 / L2 signaling, candidate cell #0-2 becomes the new serving cell SpCell #0. Also, for example, in a serving cell SCell #2 of an MCG / SCG, if an instruction to change the serving cell to candidate cell #2-1 is given by L1 / L2 signaling, candidate cell #2-1 becomes the new serving cell SCell #2.

[0061] [Serving Cell Switch Example 2] The RRC / MAC CE can configure a global candidate cell ID (cell #0,...,5) for each cell group, band, FR, and UE. The UE may be instructed to switch serving cells by the global candidate cell ID.

[0062] Figure 5 illustrates a serving cell switch example 2. Similar to Figure 3A, a pool of multiple candidate cells can be configured, and the serving cell can be switched to any (activated) candidate cell in the pool by L1 / L2 signaling. In this case, the configured candidate cell can be either an SpCell or an SCell based on the L1 / L2 signaling.

[0063] The UE may receive an indication of a serving cell change (from cell #2-1 to candidate cell 4) via MAC CE / DCI, and the indicated candidate cell #4 becomes the SpCell of the new cell group.

[0064] [Serving Cell Switch Example 3] The RRC / MAC CE can set a global candidate cell ID (cell #0-1, #0-1, ..., 2-2) for each cell group, band, FR, and UE. The UE may be instructed to switch the serving cell by the global candidate cell ID.

[0065] 6 is a diagram showing a serving cell switch example 3. The UE receives an instruction to change the serving cell (from cell #2-0 to cell #2-1) via MAC CE / DCI. The indicated cell #2-1 then becomes the SpCell of the new cell group. Furthermore, the cells (cell #0-0, cell #1-0) in the same cell group as the indicated cell #2-1 become Scell ​​#1 and Scell ​​#2. In other words, the serving cell group is switched.

[0066] (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.

[0067] 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.

[0068] The UE may control the timing of UL transmission by applying timing advance (multiple timing advances) for each pre-configured timing advance group (TAG).

[0069] 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.

[0070] 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.

[0071] 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).

[0072] 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 7). Figure 7 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).

[0073] 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.

[0074] 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. 8). The MAC CE may be configured by one octet (=8 bits).

[0075] 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 8 may be called a TAC MAC CE.

[0076] FIG. 9 illustrates another example of a MAC CE for a timing advance command. The MAC CE illustrated in FIG. 9 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. 9 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. 8. Furthermore, the absolute TAC MAC CE may not include the TAG ID field illustrated in FIG. 8.

[0077] The MAC CE shown in Fig. 8 may be used after initial access is established. On the other hand, the MAC CE shown in Fig. 9 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. 8 may be called a TA adjustment field / field for instructing TA adjustment / field related to TA adjustment, and the TAC field shown in Fig. 9 may be called an absolute TAC field / field for instructing absolute TAC.

[0078] 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.

[0079] 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.

[0080] The MAC entity receives the TAC MAC CE and performs a predetermined value (N ＴＡ ) is maintained, apply a timing advance command for the indicated TAG or start or restart the time alignment timer associated with the indicated TAG. ＴＡ ) may be the timing advance between DL and UL.

[0081] 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).

[0082] 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.

[0083] For example, when the time alignment timer expires, the following actions (e.g., predetermined PTAG action / predetermined STAG action) may be performed.

[0084] 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.

[0085] 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.

[0086] (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.

[0087] FIG. 10 is a diagram showing an example of TAG settings for multiple cells (or TRPs) with different PCIs.

[0088] 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.

[0089] 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).

[0090] 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.

[0091] It is also possible that the UE performs UL transmission of a candidate cell while taking into account the TA corresponding to the candidate cell. When taking into account the TA of the candidate cell, the UE needs to acquire the TA of the candidate cell (for example, TA acquisition of candidate cells).

[0092] As the 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). 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.

[0093] 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).

[0094] 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).

[0095] 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.

[0096] 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.

[0097] 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.

[0098] (Outline of L1L2-triggered mobility (LTM)) Fig. 11 is a diagram showing an outline of L1L2-triggered mobility (LTM). LTM and L1 / L2 inter-cell mobility may be read as interchangeable.

[0099] The UE receives candidate cell configurations from the NW during UE reconfiguration. RRC , including Tproccesing1 / Tproccesing2. T RRC (e.g., max. 10 ms) is the processing time for RRC Reconfiguration carrying candidate cell configurations. Tproccesing1 / Tproccesing2 (e.g., max. 20 ms for same FR, max. 40 ms for different FR) are the time for UE processing before and after the cell switch command, respectively. This may include L2 / 3 reconfiguration, RF retuning, baseband retuning, security update if required, etc.

[0100] DL synchronization is T search , T Δ , T margin Includes: T search (e.g., 0 ms if the cell is known, up to 60 ms if the cell is unknown) is the time it takes to search for the target cell. Δ is the time for fine tracking and acquisition of all timing information. T margin(e.g., max. 2 ms) is the time for post-processing of SSB and CSI-RS.

[0101] L1 measurement is T meas (including SMTC period (e.g. 20 ms)). T meas is the measured delay from the appearance of the target to the cell switch command.

[0102] UL synchronization is T IU , T RAR , T cmd Includes: T IU (e.g., up to 15 ms) is the time of uncertainty interruption in acquiring the first available PRACH opportunity in the new cell. RAR (e.g., maximum 4 ms) is the RAR delay time. cmd (e.g., maximum 5 ms) is the processing time for L1 / L2 commands (HARQ and paging).

[0103] T cmd T after first-data is the time at which the UE performs its first DL reception / UL transmission on the indicated beam of the target cell after RAR.

[0104] 12 is a diagram showing an example of a PDCCH-ordered RACH with RAR monitoring. In the present disclosure, a source cell and a source cell group may be interchangeable. Also, a candidate cell and a candidate cell group may be interchangeable.

[0105] The source cell may transmit information regarding the configuration of the candidate cell (e.g., candidate cell configuration information) to the UE. The source cell may also transmit a PDCCH order (e.g., DCI format 1_0) used to trigger the PRACH to the UE. The PDCCH order (or DCI) may indicate a candidate cell (e.g., one candidate cell) / Random Access Occasion (RO) that is the target of the PRACH trigger / transmission. The UE transmits the PRACH in the RACH procedure to the candidate cell based on the PDCCH order to acquire the TAG / TA.

[0106] Next, the source cell transmits a response signal (RAR) to the PRACH to the UE. The RAR may include information about the TA (e.g., TA indication). The RAR (e.g., the PDSCH containing the RAR / the PDCCH scheduling the PDSCH) may be monitored in a specific search space (e.g., the common search space (CSS)) of a specific cell (e.g., the SpCell) among the current serving cells (only within the Distributed Unit (DU)). Then, the source cell performs TA adjustment (e.g., TA maintenance).

[0107] Next, the source cell may send a cell switch command to the UE. TA information may also be moved / notified from the source cell to the target cell. The UE may control UL transmission based on the acquired TA after cell switching. For example, the UE may perform the first UL transmission using the initial TA if UL synchronization with all candidate cells has not been completed after the initial cell switch.

[0108] Fig. 13 is a diagram showing an example of a PDCCH ordered RACH without RAR monitoring. Only the differences between Fig. 13 and Fig. 12 will be described.

[0109] In the example of Fig. 13, the PDCCH order used to trigger the PRACH may indicate one or more candidate cells (e.g., multiple candidate cells) / random access occasions that are targets for PRACH trigger / transmission. The UE may transmit PRACH in the RACH procedure to candidate cells based on the PDCCH order to acquire multiple TAGs / TAs. The source cell does not transmit a PRACH response signal (e.g., RAR). The source cell may indicate TA information (e.g., TA indication) to the UE using a cell switch command.

[0110] In the present disclosure, a RACH without RAR and a RACH without RAR monitoring (e.g., a RACH without RAR monitoring) may be interpreted as interchangeable. A RACH may be interpreted as a PRACH transmission triggered by a PDCCH order. A RACH procedure / PRACH transmission without RAR monitoring may be interpreted as a RACH procedure / PRACH transmission in which RAR monitoring is not required, or a RACH procedure / PRACH transmission in which RAR monitoring is not required.

[0111] 14 is a diagram showing DCI format 1_0 that is CRC-scrambled by C-RNTI. The frequency domain resource assignment may be used, for example, for a PDCCH order (RACH) according to an instruction of the PDCCH. For example, if the frequency domain resource assignment indicates all 1s, this may mean that the DCI format 1_0 is used as a PDCCH order.

[0112] The random access preamble index may be used for contention-based random access (CBRA). For example, if the random access preamble index is all 0, it may mean that CBRA is used. The reserved bits are 12 bits when operating in a cell with spectrum shared channel access, and 10 bits otherwise.

[0113] (Analysis) As a TA acquisition method in LTM supported in Rel. 18 and later, it is expected that UE-based TA measurement will be supported in addition to RACH with RAR / RACH without RAR.

[0114] However, when UE-based TA measurement is supported, it is not clear how to specifically control the UE-based TA measurement (e.g., start timing / end timing, etc.). If TA is not acquired properly, inter-cell mobility (e.g., UL transmission after cell switching) cannot be performed properly, and communication quality may deteriorate.

[0115] Therefore, the present inventors have studied control methods (for example, start timing / end timing) when UE-based TA measurement is applied, and have come up with an example of this embodiment.

[0116] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the following embodiments / aspects (e.g., cases) may be used alone or in combination of at least two of them.

[0117] (Various Alternative Readings, etc.) In the present disclosure, "A / B" and "at least one of A and B" may be interchangeable. Also, in the present disclosure, "A / B / C" may mean "at least one of A, B, and C."

[0118] In the present disclosure, terms such as 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.

[0119] In the present disclosure, Radio Resource Control (RRC), RRC parameters, RRC messages, higher layer parameters, 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.

[0120] 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.

[0121] 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.

[0122] In the present disclosure, physical layer signaling may be, for example, Downlink Control Information (DCI), Uplink Control Information (UCI), and the like.

[0123] In the following embodiments, "multiple" and "two" may be interchangeable. Also, "TAG" and "TAG ID" may be interchangeable. Also, "cell", "CC", and "carrier" may be interchangeable. In the following embodiments, "calculate", "calculate", and "obtain" may be interchangeable.

[0124] The following description may be applied to inter-cell mobility (e.g., L1 / L2 inter cell mobility) or to communication control other than inter-cell mobility. L1 / L2 inter-cell mobility may be interpreted as at least one of cell switching, cell switch, and cell change.

[0125] (Wireless Communication Method) First Embodiment The first embodiment relates to the start timing of UE-based TA measurement applied to timing advance acquisition (for example, TA acquisition) of a candidate cell.

[0126] When the UE receives the predetermined signaling, the UE may perform UE-based TA measurement for the candidate cell. That is, the UE-based TA measurement for the candidate cell may be controlled (for example, the start timing may be determined) based on the reception of the predetermined signaling.

[0127] In the following description, a candidate cell may refer to a target serving cell, or a target serving cell and a current serving cell (source cell). Predetermined signaling may be read as a predetermined channel, a predetermined signal, a predetermined parameter, or predetermined information.

[0128] The UE-based TA measurement may be triggered / granted after the UE receives predetermined signaling. The predetermined signaling (or UE-based TA measurement instruction) may be performed for a serving cell (current serving cell or source cell), a candidate cell (target serving cell), or any cell. The predetermined signaling may be received or transmitted in the serving cell (current serving cell or source cell), a candidate cell (target serving cell), or any cell. The UE-based TA measurement may be explicitly / implicitly triggered / granted by the predetermined signaling. One or more candidate cells for the UE-based TA measurement may be explicitly / implicitly indicated / configured by the predetermined signaling.

[0129] When the UE receives predetermined signaling, the UE may autonomously perform UE-based TA measurements for one or more candidate cells configured by RRC. Also, when the UE receives predetermined signaling, the UE may autonomously perform UE-based TA measurements for one or more candidate cells indicated / configured by the predetermined signaling. Also, the UE may perform UE-based TA measurements for one or more candidate cells at the time of receiving the predetermined signaling.

[0130] The predetermined signaling may be at least one of the following options 1-1 to 1-4.

[0131] [Option 1-1] The predetermined signaling may be higher layer parameters / RRC configuration. For example, the UE may start UE-based TA measurements when it receives higher layer parameters related to UE-based TA measurements for a candidate cell (see FIG. 15 ).

[0132] FIG. 15 shows an example of a case where UE-based TA measurement for a candidate cell is initiated based on higher layer parameters / RRC configuration.

[0133] The source cell may transmit information about the configuration of the candidate cell (e.g., candidate cell configuration information) to the UE. The source cell may also transmit higher layer parameters to the UE that trigger / grant UE-based TA measurements for the candidate cell. The UE may start the UE-based TA measurements based on the higher layer parameters.

[0134] The conditions / parameters required for performing the UE-based TA measurement may be configured / instructed from the source cell to the UE. For example, at least one of the higher layer parameters for triggering / granting the UE-based TA measurement and the higher layer parameters for configuring information on the candidate cell may include the conditions / parameters required for performing the UE-based TA measurement (e.g., measurement conditions, information on DL reference signals / resources for measurement, index / period / offset of the DL reference signals / resources, and at least one of the target candidate cells).

[0135] When the UE receives the higher layer parameters, it may receive / measure DL signals transmitted from one or more cells, including at least the candidate cell, and obtain (or calculate / compute) the TA of the candidate cell.

[0136] For example, for a certain cell (e.g., a candidate cell), the UE receives / measures DL signals transmitted from one or more cells including at least the candidate cell before receiving a cell switch instruction (e.g., a cell switch command), and calculates the TA of the candidate cell. Then, the UE may apply the calculated TA to UL transmission (e.g., UL transmission to a candidate cell instructed to switch to the serving cell by the cell switch command) after receiving the cell switch command for the candidate cell. In the present disclosure, the cell switch command may be interpreted as a cell switch instruction. The cell switch instruction / cell switch command may be transmitted by at least one of DCI and MAC CE.

[0137] 15 illustrates a case where information about a candidate cell to be configured (candidate cell configuration information) and higher layer parameters for triggering / granting UE-based TA measurements are transmitted separately from a source cell, but this is not limiting. UE-based TA measurements may be triggered by the information about the candidate cell (candidate cell configuration information).

[0138] One or more TA acquisition methods to be applied to each candidate cell may be configured by information about the candidate cell (candidate cell configuration information). In this case, when the UE receives higher layer parameters that trigger / grant the UE-based TA measurement, the UE may perform UE-based TA measurement for the candidate cell for which the UE-based TA measurement is configured.

[0139] [Option 1-2] The predetermined signaling may be signaling used for other configuration / instruction (other than UE-based TA measurement). The signaling used for other configuration / instruction (or specific signaling used for a certain purpose) may be, for example, at least one of signaling used for configuration / instruction of L1 beam measurement / reporting of a candidate cell, signaling used for configuration / instruction of activation of a TCI state of a candidate cell, and a MAC CE for TAC.

[0140] The UE may initiate UE-based TA measurements when it receives specific signaling used for a certain purpose (see Figure 16).

[0141] FIG. 16 shows an example in which UE-based TA measurements for a candidate cell are initiated based on specific signaling used for a certain application.

[0142] The source cell may transmit information regarding the configuration of the candidate cell (e.g., candidate cell configuration information) to the UE. The source cell may also transmit specific signaling used for a certain purpose. The specific signaling used for a certain purpose may be, for example, at least one of signaling for configuring / instructing L1 beam measurement / reporting of the candidate cell, signaling for configuring / instructing activation of the TCI state of the candidate cell, and a MAC CE for TAC. These signals make it possible to further narrow down candidate cells that are likely to be target cells for L1 / L2 mobility. Of course, the specific signaling used for a certain purpose is not limited to these, and other signaling may also be applied.

[0143] The UE may start the UE-based TA measurement based on specific signaling used for a certain purpose. The specific signaling used for a certain purpose is not limited to the above-mentioned signaling, and signaling used for other purposes may also be applied.

[0144] The conditions / parameters required for performing the UE-based TA measurement may be set / instructed to the UE from the source cell. For example, the higher layer parameters for setting information related to the candidate cell may include the conditions / parameters required for performing the UE-based TA measurement (e.g., measurement conditions, information related to the DL signal / DL reference signal to be measured (e.g., DL reference signal ID / period / offset, etc.)).

[0145] When the UE receives the higher layer parameters, it may receive / measure DL signals transmitted from one or more cells, including at least the candidate cell, and obtain (or calculate / compute) the TA of the candidate cell.

[0146] For example, for a certain cell (e.g., a candidate cell), the UE may receive / measure DL signals transmitted from one or more cells including at least the candidate cell before receiving a cell switch instruction (e.g., a cell switch command) to calculate the TA of the candidate cell. Then, the UE may apply the calculated TA to UL transmissions (e.g., UL transmissions to a candidate cell instructed to switch to the serving cell by the cell switch command) after receiving the cell switch command for the candidate cell.

[0147] [Option 1-3] The predetermined signaling may be downlink control information (e.g., DCI). The DCI may be DCI for a PDCCH order (e.g., PDCCH ordered RACH). For example, when the UE receives the DCI, the UE may start UE-based TA measurement (see FIG. 17 ).

[0148] The source cell may transmit information about the configuration of the candidate cell (e.g., candidate cell configuration information) to the UE. The source cell may also transmit DCI (e.g., DCI for a PDCCH order) to the UE. The UE may start UE-based TA measurements based on the DCI.

[0149] For example, for a certain cell (e.g., a candidate cell), the UE may receive / measure DL signals transmitted from one or more cells including at least the candidate cell before receiving a cell switch instruction (e.g., a cell switch command) to calculate the TA of the candidate cell. Then, the UE may apply the calculated TA to UL transmissions (e.g., UL transmissions to a candidate cell instructed to switch to the serving cell by the cell switch command) after receiving the cell switch command for the candidate cell.

[0150] A candidate cell may be explicitly indicated by the DCI (e.g., a field included in the DCI). Also, a current serving cell may be explicitly indicated by the DCI (e.g., a field included in the DCI). The DCI serving as the predetermined signaling may be any DCI for a PDCCH order used for a RACH trigger, or may be a specific DCI for a PDCCH order used for a RACH trigger (e.g., a DCI corresponding to with / without RAR monitoring).

[0151] A TA acquisition method (e.g., an initial TA acquisition method) may be configured separately for each candidate cell (e.g., configured by a higher layer parameter). In the case where a TA acquisition method is configured for each candidate cell, when a UE receives a DCI (e.g., a DCI for a PDCCH order), the UE may determine a TA acquisition method to be applied to the candidate cell based on at least one of the candidate cell (or the number of candidate cells) indicated by the DCI and the TA acquisition method configured for the candidate cell.

[0152] [[When only one TA acquisition method is configured for a candidate cell]] When only one method is configured as the initial TA acquisition method for each candidate cell, at least one of the following options 1-3a / 1-3b / 1-3c / 1-3d may be applied. The initial TA acquisition method may include at least one of PDCCH order RACH with RAR monitoring, PDCCH order RACH without RAR monitoring, and UE based TA measurement.

[0153] <<Option 1-3a>> Only one candidate cell may be indicated by one DCI, and the candidate cells may include the target serving cell and the current serving cell.

[0154] If the candidate cell indicated by the DCI is a candidate cell for which a PDCCH order (or a RACH procedure (RACH procedure with / without RAR)) is configured as the initial TA acquisition method, the UE may perform the RACH procedure.

[0155] If the candidate cell indicated by the DCI is a candidate cell for which UE-based TA measurement is set as the initial TA acquisition method, the UE may perform TA measurement on its own terminal.

[0156] This makes it possible to indicate the TA acquisition method set in the candidate cell even when using DCI (for example, DCI for a PDCCH order).

[0157] <<Option 1-3b>> Multiple candidate cells may be indicated by one DCI, and the candidate cells may include the target serving cell and the current serving cell.

[0158] The multiple cells indicated by the DCI may be limited to cells for which the same TA acquisition method is configured (option 1-3b-1). For example, when indicating multiple candidate cells using DCI, the base station may perform control so as to indicate multiple candidate cells for which the same TA acquisition method is configured. When multiple candidate cells are indicated by DCI, the UE may expect / assume that the same TA acquisition method is configured for the multiple candidate cells. When the UE receives DCI, it may perform TA acquisition based on the TA acquisition method (RACH procedure / UE-based TA measurement) configured for the multiple candidate cells indicated by DCI.

[0159] Alternatively, different TA acquisition methods may be configured for multiple cells indicated by the DCI (option 1-3b-2). For example, when a base station indicates multiple candidate cells using DCI, it may indicate multiple candidate cells for which different TA acquisition methods are configured. When the UE receives DCI, it may perform TA acquisition for each of the multiple candidate cells indicated by the DCI based on the TA acquisition method (RACH procedure / UE-based TA measurement) configured for each candidate cell.

[0160] <<Option 1-3c>> A predetermined field of the DCI may be used to trigger UE-based TA measurements for one or more candidate cells for which the UE-based TA measurement is configured as the initial TA acquisition method configured by the RRC. For example, when the predetermined field of the DCI has a specific value (e.g., 1), the UE may perform UE-based TA measurements for one or more candidate cells for which the UE-based TA measurement is configured as the initial TA acquisition method.

[0161] If the predetermined field of the DCI has another value (e.g., 0), the UE may control not to perform UE-based TA measurement for a candidate cell for which UE-based TA measurement is configured as the initial TA acquisition method. In this case, the UE may perform PRACH transmission (e.g., TA acquisition based on the RA procedure) based on the DCI.

[0162] In this case, even if a candidate cell is not indicated by DCI, it is possible to trigger UE-based TA measurement for a candidate cell for which UE-based TA measurement is set as the initial TA acquisition method. This makes it unnecessary to indicate a candidate cell by DCI, thereby suppressing an increase in DCI overhead.

[0163] Here, a case where UE-based TA measurement is set as the initial TA acquisition method is shown, but this is not limited to this and may also be applied when another TA acquisition method is set.

[0164] <<Option 1-3d>> Even if there is no explicit instruction in a predetermined field of the DCI, UE-based TA measurement may be triggered for one or more candidate cells for which the UE-based TA measurement is configured as the initial TA acquisition method configured by the RRC in response to reception of the DCI. In this case, the PDCCH order (DCI) for triggering the RACH for the candidate cells may be regarded as an implicit instruction to trigger UE-based TA measurement for the candidate cells for which the UE-based TA measurement is configured as the initial TA acquisition method by the RRC.

[0165] In this case, instructions to use a specific field in DCI may be unnecessary.

[0166] [[When configuration of multiple TA acquisition methods for candidate cells is supported]] When configuration of one or more (or multiple) methods as initial TA acquisition methods is supported for each candidate cell, at least one of the following options 1-3a' / 1-3b' / 1-3c' may be applied. The initial TA acquisition methods may include at least one of PDCCH order RACH with RAR monitoring, PDCCH order RACH without RAR monitoring, and UE based TA measurement.

[0167] <<Option 1-3a′>> Only one candidate cell may be indicated by one DCI. The candidate cells may include the target serving cell and the current serving cell. The DCI may also indicate a TA acquisition method to be applied to the candidate cell. For example, a DCI field (e.g., an additional field / TA acquisition method indication field) may indicate either UE-based TA measurement or PRACH.

[0168] If the candidate cell indicated by the DCI is a candidate cell for which a PDCCH order (or a RACH procedure (RACH procedure with / without RAR)) and UE-based TA measurement are configured as the initial TA acquisition method, the UE may determine the TA acquisition method to apply based on an additional field (or a TA acquisition method indication field) in the DCI.

[0169] For example, if the additional field has a particular value (e.g., 1), the UE may perform UE-based TA measurements for the indicated candidate cells, whereas if the additional field has another value (e.g., 0), the UE may perform a RACH procedure.

[0170] <<Option 1-3b'>> Multiple candidate cells may be indicated by one DCI. The candidate cells may include the target serving cell and the current serving cell. The TA acquisition method to be applied to each candidate cell may be indicated commonly or individually. For example, one of UE-based TA measurement and PRACH may be indicated by a DCI field (e.g., an additional field / TA acquisition method indication field).

[0171] When multiple candidate cells are indicated by DCI, a common TA acquisition method to be applied to the multiple candidate cells may be indicated by a field of the DCI (e.g., an additional field / TA acquisition method indication field) (option 1-3b'-1). When multiple candidate cells are indicated by DCI, the UE may determine a TA acquisition method to be applied commonly to the multiple candidate cells based on a field of the DCI (e.g., an additional field / TA acquisition method indication field). In this case, the TA acquisition method to be applied to the multiple candidate cells can be indicated by using one field (e.g., an additional field / TA acquisition method indication field).

[0172] When multiple candidate cells are indicated by DCI, the TA acquisition method to be applied to each of the multiple candidate cells may be individually indicated by multiple fields of the DCI (e.g., additional field / TA acquisition method indication field) (Option 1-3b'-2). When multiple candidate cells are indicated by DCI, the UE may determine the TA acquisition method to be applied to each of the multiple candidate cells based on the multiple fields of the DCI (e.g., additional field / TA acquisition method indication field). In this case, it is possible to indicate the TA acquisition method to be applied to each of the multiple candidate cells.

[0173] <<Option 1-3c'>> A predetermined field of the DCI may be used to trigger UE-based TA measurements for one or more candidate cells for which the UE-based TA measurement is configured as the initial TA acquisition method configured by the RRC. For example, when the predetermined field of the DCI has a specific value (e.g., 1), the UE may perform UE-based TA measurements for one or more candidate cells for which the UE-based TA measurement is configured as the initial TA acquisition method.

[0174] If the predetermined field of the DCI has another value (e.g., 0), the UE may perform PRACH transmission (e.g., TA acquisition based on the RA procedure).

[0175] In this case, even if a candidate cell is not indicated by DCI, it is possible to trigger UE-based TA measurement for a candidate cell for which the UE-based TA measurement / RACH procedure is set as the initial TA acquisition method. This makes it unnecessary to indicate a candidate cell by DCI, thereby suppressing an increase in DCI overhead.

[0176] [Option 1-4] The predetermined signaling may be a cell switch command (e.g., MAC CE). For example, the UE may start UE-based TA measurement when receiving the cell switch command (see FIG. 18).

[0177] FIG. 18 shows an example of a case where UE-based TA measurement for a candidate cell is started based on a cell change command.

[0178] The source cell may transmit information regarding the configuration of the candidate cell (e.g., candidate cell configuration information) to the UE. The source cell may also transmit a cell switch command (e.g., MAC CE). The cell switch command may trigger / grant UE-based TA measurements for the candidate cell in addition to the cell switch. The UE may start the UE-based TA measurements based on the cell switch command.

[0179] The conditions / parameters required for performing the UE-based TA measurements may be configured / instructed to the UE from the source cell. For example, at least one of the cell switching command for triggering / granting the UE-based TA measurements and the higher layer parameters for configuring information on the candidate cells may include the conditions / parameters required for performing the UE-based TA measurements (e.g., measurement conditions, information on DL reference signals / resources for measurement, index / period / offset of the DL reference signals / resources, and at least one of the target candidate cells).

[0180] The UE may be controlled to perform UE-based TA measurements for candidate cells for which switching to the serving cell is instructed by the cell switching command.

[0181] One or more TA acquisition methods to be applied to each candidate cell may be configured by information about the candidate cell (candidate cell configuration information). In this case, when the UE receives a cell switching command that triggers / grants the UE-based TA measurement, the UE may perform UE-based TA measurement for the candidate cell for which the UE-based TA measurement is configured.

[0182] When the UE receives a cell switching command, it may receive / measure DL signals transmitted from one or more cells including at least the candidate cell, and obtain (or calculate / compute) the TA of the candidate cell.

[0183] For example, after receiving a cell switch instruction (e.g., a cell switch command), the UE receives / measures DL signals transmitted from one or more cells including at least the candidate cell and calculates the TA of the candidate cell. Then, the UE may apply the calculated TA to UL transmissions to the candidate cell that is instructed to be switched to the serving cell by the cell switch command.

[0184] <Second embodiment> The second embodiment relates to the end timing of UE-based TA measurement applied to timing advance acquisition (e.g., TA acquisition) of a candidate cell. The second embodiment may be applied in combination with the first embodiment or may be applied alone.

[0185] When the UE receives the predetermined signaling, the UE may stop the UE-based TA measurement for the candidate cell. That is, the UE-based TA measurement for the candidate cell may be controlled (e.g., the termination timing may be determined) based on the reception of the predetermined signaling. In the present disclosure, the terms "stop," "terminate," "stop," "cancel," and "release" may be read as interchangeable terms.

[0186] The predetermined signaling (or an instruction to stop UE-based TA measurements) may be sent to a serving cell (current serving cell or source cell), a candidate cell (target serving cell), or any cell. The predetermined signaling may be received or transmitted by a serving cell (current serving cell or source cell), a candidate cell (target serving cell), or any cell. The predetermined signaling may explicitly / implicitly trigger / grant the stopping of UE-based TA measurements. One or more candidate cells for which UE-based TA measurements are to be stopped may be explicitly / implicitly indicated / configured by the predetermined signaling.

[0187] The predetermined signaling may be at least one of the following options 2-1 to 2-4.

[0188] [Option 2-1] The predetermined signaling may be a higher layer parameter / RRC configuration. For example, the UE may stop UE-based TA measurements when it receives higher layer parameters related to UE-based TA measurements for a candidate cell.

[0189] For example, the higher layer parameters related to the UE-based TA measurement for the candidate cell may set the release / stop of the UE-based TA measurement. Furthermore, the higher layer parameters may set (or reconfigure) another TA acquisition method different from the UE-based TA measurement. When the higher layer parameters set (or reconfigure) another TA acquisition method different from the UE-based TA measurement, the UE may stop the UE-based TA measurement and start the other TA acquisition method.

[0190] One or more candidate cells for which UE-based TA measurements are to be stopped may be configured by an upper layer parameter instructing the UE to stop UE-based TA measurements. Alternatively, the candidate cells for which UE-based TA measurements are to be stopped may not be configured by the upper layer parameter, and when the UE receives the upper layer parameter, the UE may stop UE-based TA measurements in all candidate cells for which UE-based TA measurements are being performed.

[0191] [Option 2-2] The predetermined signaling may be signaling used for other configurations / instructions (other than UE-based TA measurements). The signaling used for other configurations / instructions (or specific signaling used for a certain purpose) may be, for example, at least one of signaling used for configuration / instruction of deactivation of L1 beam measurement / reporting (e.g., L1 beam measurement / reporting) of a candidate cell, signaling used for configuration / instruction of deactivation of a TCI state of a candidate cell, and a MAC CE for TAC.

[0192] The UE may stop UE-based TA measurements when it receives specific signaling used for a certain purpose.

[0193] One or more candidate cells for which UE-based TA measurements are to be stopped may be configured by specific signaling used for a certain purpose. Alternatively, the candidate cells for which UE-based TA measurements are to be stopped may not be configured by the specific signaling, and when the UE receives the specific signaling, the UE may stop UE-based TA measurements in all candidate cells for which UE-based TA measurements are being performed.

[0194] [Option 2-3] The predetermined signaling may be downlink control information (e.g., DCI). The DCI may be DCI for a PDCCH order (e.g., PDCCH ordered RACH). For example, when the UE receives the DCI, the UE may stop UE-based TA measurements.

[0195] The DCI may indicate one or more candidate cells for which UE-based TA measurements are to be stopped. For example, a predetermined field in the DCI may be used to indicate the candidate cells for which UE-based TA measurements are to be stopped. Alternatively, a predetermined field in the DCI may be used to indicate the current serving cell for which UE-based TA measurements are to be stopped. The DCI serving as the predetermined signaling may be any DCI for a PDCCH order used for RACH triggering, or may be a specific DCI for a PDCCH order used for RACH triggering (e.g., a DCI corresponding to RAR monitoring on / without RAR monitoring on).

[0196] When the DCI is used to support the indication of the start and stop of UE-based TA measurement, the DCI may indicate whether the measurement is to be started or stopped. For example, a certain field in the DCI may be used to indicate whether the measurement is to be started or stopped. Furthermore, the UE may be controlled so that it stops the UE-based TA measurement when it receives DCI if the UE-based TA measurement has been started (or for a candidate cell for which the measurement has been started), and starts the UE-based TA measurement when it receives DCI if the UE-based TA measurement has been stopped (or for a candidate cell for which the measurement has been stopped).

[0197] [Option 2-4] The predetermined signaling may be a cell switch command (e.g., MAC CE). For example, the UE may stop UE-based TA measurements when it receives the cell switch command.

[0198] A candidate cell / serving cell for which UE-based TA measurements are to be stopped may be determined based on the candidate cell / serving cell for which switching is instructed by the cell switch command. For example, when a cell switch command is transmitted for cell switching to cell #C, the UE may be controlled to stop UE-based TA measurements for candidate cells other than cell #C.

[0199] The cell switching command may also indicate one or more candidate cells for which UE-based TA measurements are to be stopped. Alternatively, when the UE receives the cell switching command, the UE may stop UE-based TA measurements in all candidate cells for which UE-based TA measurements are being performed.

[0200] [Variation] The stop (or expiration) of UE-based TA measurement may be controlled based on a predetermined timer. The predetermined timer may be set / instructed by the RRC / MAC CE. The predetermined timer may be set / instructed separately for each candidate cell, or may be set / instructed commonly for multiple candidate cells. The UE may control the UE to stop the UE-based TA measurement when the predetermined timer expires. Note that, when the start timing of the UE-based TA measurement is started based on at least one of options 1-1 to 1-4 of the first embodiment, the UE may start the predetermined timer after receiving predetermined signaling instructing / setting the start of the UE-based TA measurement.

[0201] Third Embodiment The third embodiment relates to at least one of the start timing and end timing of a UE operation (for example, the UE operation shown in the first embodiment / second embodiment) after receiving predetermined signaling.

[0202] The third embodiment may be applied in combination with at least one of the first embodiment and the second embodiment.

[0203] When the UE receives predetermined signaling that triggers the start of UE-based TA measurement or predetermined signaling that instructs the stop of UE-based TA measurement, the UE may apply the following Option 3-1 / Option 3-2.

[0204] [Option 3-1] When the UE receives predetermined signaling (e.g., DCI / MAC CE) that triggers the start of UE-based TA measurement or predetermined signaling that instructs the stop of UE-based TA measurement, the UE may be controlled to apply the UE operation described in the first embodiment / second embodiment after a predetermined period from the reception timing (see FIG. 19A). The reception timing may be interpreted as a reception symbol or a reception slot. The predetermined period may be x ms, x symbols, or x slots.

[0205] Figure 19A shows a case where the UE operation (e.g., start / stop of UE-based TA measurement) shown in the first embodiment / second embodiment is applied x ms / x symbols after the reception timing of a specified signaling (e.g., from the received symbol).

[0206] x may be defined in the specification, set by a higher layer parameter, or may be a value reported as a UE capability.

[0207] [Option 3-2] When the UE receives predetermined signaling (e.g., DCI / MAC CE) that triggers the start of UE-based TA measurement or predetermined signaling that instructs the stop of UE-based TA measurement, the UE may be controlled to apply the UE operation described in the first embodiment / second embodiment after a predetermined period from the timing of transmitting a HARQ-ACK (e.g., ACK) in response to the predetermined signaling (see FIG. 19B ). The transmission timing may be interpreted as a transmission symbol or a transmission slot. The predetermined period may be y ms, y symbols, or y slots.

[0208] Figure 19B shows a case where the UE operation (e.g., start / stop of UE-based TA measurement) shown in the first embodiment / second embodiment is applied yms / y symbols after the transmission timing of an ACK for specified signaling (e.g., from the transmission symbol).

[0209] y may be defined in the specification, set by a higher layer parameter, or may be a value reported as a UE capability.

[0210] <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.

[0211] 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.

[0212] 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.

[0213] Furthermore, notification of any information to the UE in the above embodiments may be performed periodically, semi-persistently, or aperiodically.

[0214] [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.

[0215] 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.

[0216] If the notification is made by UCI, the notification may be transmitted using PUCCH or PUSCH.

[0217] Furthermore, any information in the above-described embodiments may be notified from the UE periodically, semi-persistently, or aperiodically.

[0218] [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.

[0219] At least one of the above embodiments (or options for each embodiment) may be applied only to UEs that have reported or support a particular UE capability.

[0220] The specific UE capability may indicate at least one of the following: Supporting specific processes / operations / controls / information for at least one of the above embodiments (e.g., UE-based TA measurements), Supporting specific processes / operations / controls / information for at least one of the options or combinations of options for the above embodiments.

[0221] 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).

[0222] 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)).

[0223] 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 / physical layer signaling, for example, the specific information may be information indicating enabling a random access procedure / PRACH transmission without RAR monitoring, any RRC parameters for a specific release (e.g., Rel. 18 / 19), etc.

[0224] 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, Rel. 15 / 16 behavior.

[0225] (Supplementary Notes) The following inventions are supplementary notes regarding one embodiment of the present disclosure. [Supplementary Note 1] A terminal comprising: a receiving unit that receives signaling instructing terminal-based timing advance measurement for one or more candidate cells; and a control unit that determines at least one of a timing advance acquisition method to be applied to the candidate cell, a start timing of the terminal-based timing advance measurement to be applied to the candidate cell, and a start timing of the terminal-based timing advance measurement to be applied to the candidate cell, based on at least one of the signaling and a timing advance acquisition method configured for the candidate cell. [Supplementary Note 2] The terminal according to Supplementary Note 1, wherein the signaling is a predetermined higher layer parameter. [Supplementary Note 3] The terminal according to Supplementary Note 1 or Supplementary Note 2, wherein the signaling is downlink control information transmitted in a downlink control channel order used to trigger a random access channel. [Supplementary Note 4] The terminal according to any of Supplementary Notes 1 to 3, wherein the signaling is a cell switching command.

[0226] (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.

[0227] 20 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).

[0228] 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.

[0229] 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.

[0230] 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))).

[0231] 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.

[0232] 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).

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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.

[0237] 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.

[0238] The user terminal 20 may be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0239] 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).

[0240] 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.

[0241] 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.

[0242] 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.

[0243] 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).

[0244] 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.

[0245] 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.

[0246] 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.

[0247] 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.

[0248] 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.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] 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).

[0253] 21 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.

[0254] 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.

[0255] 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.

[0256] 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.

[0257] 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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.

[0264] 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.

[0265] 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.

[0266] 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.

[0267] 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.

[0268] 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.

[0269] The transmitter and receiver of the base station 10 in the present disclosure may be configured by at least one of the transmitter / receiver 120, the transmitter / receiver antenna 130, and the transmission path interface 140.

[0270] The transceiver 120 may transmit signaling to indicate terminal-based timing advance measurements for one or more candidate cells.

[0271] The control unit 110 may instruct at least one of the timing advance acquisition method to be applied to the candidate cell, the start timing of the terminal-based timing advance measurement to be applied to the candidate cell, and the start timing of the terminal-based timing advance measurement to be applied to the candidate cell based on at least one of the signaling and the timing advance acquisition method set for the candidate cell.

[0272] (User terminal) Fig. 22 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.

[0273] 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.

[0274] 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.

[0275] 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.

[0276] 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.

[0277] 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.

[0278] 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.

[0279] 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.

[0280] 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.

[0281] 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.

[0282] 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.

[0283] 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.

[0284] 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.

[0285] 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.

[0286] 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.

[0287] 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.

[0288] 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.

[0289] 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.

[0290] The transceiver 220 may receive signaling that indicates terminal-based timing advance measurements for one or more candidate cells.

[0291] The control unit 210 may determine at least one of the timing advance acquisition method to be applied to the candidate cell, the start timing of the terminal-based timing advance measurement to be applied to the candidate cell, and the start timing of the terminal-based timing advance measurement to be applied to the candidate cell based on at least one of the signaling and the timing advance acquisition method set for the candidate cell.

[0292] The signaling may be a predetermined higher layer parameter, downlink control information transmitted in a downlink control channel order used to trigger a random access channel, or a cell switch command.

[0293] (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.

[0294] 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.

[0295] 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. 23 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.

[0296] 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.

[0297] 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.

[0298] 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.

[0299] 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.

[0300] 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.

[0301] 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.

[0302] 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.

[0303] 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.

[0304] 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).

[0305] 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.

[0306] 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.

[0307] (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.

[0308] 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.

[0309] 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.

[0310] 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.

[0311] 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.

[0312] 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.

[0313] 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.

[0314] 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.

[0315] 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.

[0316] 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.

[0317] 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.

[0318] 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.

[0319] 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.

[0320] 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.

[0321] 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.

[0322] 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.

[0323] 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.

[0324] 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.

[0325] 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."

[0326] 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.

[0327] 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.

[0328] 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.

[0329] 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.

[0330] 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.

[0331] 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.

[0332] 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.

[0333] 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).

[0334] 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).

[0335] 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).

[0336] 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.

[0337] 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.

[0338] 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).

[0339] 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.

[0340] 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.

[0341] 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.

[0342] 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.

[0343] 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.

[0344] 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.

[0345] 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.

[0346] 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.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0351] 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.

[0352] 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.

[0353] 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.

[0354] 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.

[0355] 24 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.

[0356] 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.

[0357] 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).

[0358] 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.

[0359] 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.

[0360] 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.

[0361] 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.

[0362] 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.

[0363] 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).

[0364] 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.

[0365] 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)).

[0366] 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.

[0367] 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.

[0368] 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.

[0369] 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.

[0370] 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.

[0371] 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).

[0372] 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."

[0373] 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.

[0374] 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.

[0375] 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.

[0376] 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.

[0377] 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...."

[0378] 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).

[0379] 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.

[0380] 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."

[0381] 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.

[0382] 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."

[0383] 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.

[0384] 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.

[0385] 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").

[0386] In this disclosure, the terms "of," "for," "regarding," "related to," "associated with," etc. may be read interchangeably.

[0387] 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.

[0388] 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.

[0389] 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 receiving unit that receives upper-layer parameters relating to terminal-based timing advance (TA) measurement, A terminal having a control unit that stops the terminal-based TA measurement in one or more candidate cells based on the upper layer parameters.

2. The terminal according to claim 1, further comprising a transmitting unit that transmits capability information indicating support for the terminal-based TA measurement.

3. The one or more candidate cells are candidate cells of layer1 / layer2-triggered mobility (LTM), The terminal according to claim 1, wherein the receiving unit receives a cell switching command for one of the one or more candidate cells after stopping the terminal-based TA measurement in the one or more candidate cells.

4. A step of receiving upper layer parameters relating to terminal-based timing advance (TA) measurement, A wireless communication method for a terminal, comprising the step of stopping the terminal-based TA measurement in one or more candidate cells based on the upper layer parameters.

5. A transmission unit that transmits higher layer parameters relating to terminal-based timing advance (TA) measurement, A base station having a control unit that instructs the cessation of terminal-based TA measurement in one or more candidate cells based on the aforementioned upper-layer parameters.

6. A system having a terminal and a base station, The aforementioned terminal is A receiving unit that receives higher-layer parameters related to terminal-based timing advance (TA) measurement, The system includes a control unit that stops the terminal-based TA measurement in one or more candidate cells based on the aforementioned upper-layer parameters, The aforementioned base station is A system having a transmission unit that transmits the aforementioned higher-layer parameters.