Terminals, wireless communication methods, base stations and systems

Abstract

A terminal according to one aspect of the present disclosure comprises a control unit that performs a UE-based timing advance measurement for a candidate cell, and a reception unit that receives a setting relating to a timer or a threshold value for determining the validity of a timing advance obtained by the UE-based timing advance measurement. The control unit determines the validity of the timing advance on the basis of the setting.

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 non-serving cells, 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] 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.

[0007] However, if UE-based TA measurement is supported, it is not clear how to handle the acquired TA (for example, how to determine the validity of the acquired TA).

[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 has a control unit that performs UE-based timing advance measurements for a candidate cell, and a receiving unit that receives settings related to a timer or threshold for determining the validity of the timing advance obtained by the UE-based timing advance measurements, and the control unit determines the validity of the timing advance based on the settings.

[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 movement in Rel. 17. Figure 1B is a diagram showing an example of UE movement 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 is supported for candidate cells. Figure 11 is a diagram showing an example of a MAC CE for timing advance reporting. FIG. 12 is a diagram illustrating an overview of L1L2-triggered mobility (LTM). FIG. 13 is a diagram illustrating a PDCCH-instructed RACH (PDCCH-ordered RACH) with random access response (RAR) monitoring for a serving cell. FIG. 14 is a diagram illustrating a PDCCH-instructed RACH (PDCCH-ordered RACH) without random access response (RAR) monitoring for a candidate cell. FIG. 15 is a diagram illustrating an example of UE-based TA measurements. FIG. 16 is a diagram illustrating an example of UE-based TA measurements according to the 0th embodiment. FIG. 17 is a diagram illustrating an example of criteria for determining the validity of TA according to the first embodiment. FIG. 18 is a diagram illustrating an example of criteria for determining the validity of TA according to the first embodiment. FIG. 19 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. FIG. 20 is a diagram illustrating an example of a configuration of a base station according to an embodiment. FIG. 21 is a diagram illustrating an example of a configuration of a user terminal according to an embodiment. FIG. 22 is a diagram illustrating an example of hardware configurations of a base station and a user terminal according to an embodiment. FIG. 23 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) 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 SSB configuration for beam measurement of the TRP corresponding to a PCI different from that of the serving cell, and the configuration required to use radio resources for data transmission and reception (including resources of the different PCI). (2) The UE performs beam measurement of the TRP corresponding to the different PCI and reports the beam measurement results to the serving cell. (3) Based on the above report, the Transmission Configuration Indication (TCI) state associated with the TRP corresponding to the different PCI is activated by L1 / L2 signaling from the serving cell. (4) The UE transmits and receives using a UE-dedicated channel on the TRP corresponding to the different PCI. (5) The UE must always cover the serving cell, including in the case of multiple TRPs. As in conventional systems, the UE must use common channels from the serving cell, such as the Broadcast Control Channel (BCCH) and the Paging Channel (PCH).

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

[0032] <Scenario 2> Scenario 2 applies L1 / L2 inter-cell mobility (e.g., L1L2-triggered mobility (LTM)). L1 / L2 inter-cell mobility enables the serving cell to be changed using functions such as beam control without RRC reconfiguration. In other words, transmission and reception with a candidate cell / additional cell is possible without handover. Since handover requires RRC reconnection and creates a period when data communication is unavailable, applying L1 / L2 inter-cell mobility that does not require handover makes it possible to continue data communication even when the serving cell is changed. Scenario 2 may be applied, for example, in Rel. 18. In scenario 2, for example, the following procedure is performed.

[0033] (1) The UE receives configuration information (e.g., SSB configuration, etc.) for a cell with a different PCI (additional cell / candidate cell / target serving cell) from the serving cell (current serving cell) for beam measurement / serving cell change. (2) The UE performs beam measurement of the cell using the different PCI and reports the measurement results to the serving cell. (3) The UE may receive the configuration of the cell with a different PCI (serving cell / candidate cell configuration) via higher layer signaling (e.g., RRC). That is, pre-configuration for the serving cell change may be performed. This configuration may be performed together with the configuration in (1) or separately. (4) Based on the above report, the TCI state of the cell with the different PCI may be activated via L1 / L2 signaling according to the serving cell change. The activation of the TCI state and the serving cell change may be performed separately. (5) The UE changes the serving cell (assumed serving cell) and starts receiving / transmitting using the pre-configured UE-specific channel and TCI state.

[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). Here, the example shows a case where the serving cell is switched from PCI #1 corresponding to the current serving cell (e.g., current serving cell) to PCI #3 corresponding to the target serving cell (e.g., target serving cell) by L1 / L2 signaling.

[0036] The UE can receive / transmit common channels (e.g., system information / paging / short messages) / UE-dedicated channels to / from the new serving cell (target serving cell #3), which may cause the UE to move out of the coverage of the previous serving cell PCI #1.

[0037] (Setting of multiple candidate cells) Figure 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 (for example, a current serving cell / a candidate cell to become the 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.

[0038] Candidate cells (e.g., candidate cells that are not the target serving cell / current serving cell) may be associated with the SpCell / SCell. In FIG. 2, SpCell #0 is associated with candidate cells #0-1, #0-2, and #0-3. SCell #1 is associated with candidate cell #1-1. SCell #2 is associated with candidate cells #2-1 and #2-2. In this way, one or more candidate cells (e.g., candidate cells that are not the target serving cell / current serving cell) may be associated with a serving cell.

[0039] Alternatively, candidate cells may not be explicitly associated with each serving cell.

[0040] Regarding the setting of candidate cells to be candidates when changing the serving cell, for example, the following options 1 and 2 are possible.

[0041] <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.

[0042] 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.

[0043] <Option 2> For multiple candidate cells, a complete configuration (e.g., ServingCellConfig) corresponding to each cell may be applied. That is, the candidate cell may not share configuration information with the serving cell, and a separate configuration (e.g., separate upper layer parameters) may be applied. The UE is provided with the complete configuration of each candidate cell, so that it can communicate properly with the candidate cells.

[0044] For example, multiple candidate cells may be associated with each serving cell by reusing the carrier aggregation (CA) configuration framework. In the CA configuration framework, an SpCell may be configured for each cell group, and multiple SCells may be added. For example, a serving cell may be configured and multiple candidate cells may be configured for each cell group for L1 / L2 inter-cell mobility. Candidate cells may be activated / deactivated by MAC CE. Candidate cells may be activated / deactivated by activating / deactivating TCI information corresponding to the candidate cells by MAC CE. This method is considered to be beneficial for reducing the complexity of UE operations.

[0045] 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.

[0046] 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.

[0047] (Signaling for Serving Cell Change Indication) At least one of implicit signaling and explicit signaling may be used to indicate a serving cell change.

[0048] [Aspect 1] In aspect 1, implicit signaling for a serving cell change indication is described.

[0049] [[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.

[0050] 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.

[0051] [[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.

[0052] 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).

[0053] [[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.

[0054] [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.

[0055] [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.

[0056] 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.

[0057] (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).

[0058] 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.

[0059] 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.

[0060] [[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.

[0061] [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).

[0062] 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.

[0063] [Serving Cell Switch Example 1] Fig. 4 is a diagram showing Serving Cell Switch Example 1. Fig. 4 shows a case where candidate cells are associated with each serving cell.

[0064] For example, in the serving cell SpCell #0 of the MCG / SCG, when L1 / L2 signaling instructs that the candidate cell #0-2 be changed to a serving cell (e.g., SpCell), the candidate cell #0-2 becomes the new serving cell SpCell. That is, switching between the serving cell SpCell #0 and the candidate cell #0-2 is performed.

[0065] In addition, in the serving cell SCell #2 of the MCG / SCG, when the candidate cell #2-1 is instructed to be changed to a serving cell (for example, SCell) by L1 / L2 signaling, the candidate cell #2-1 becomes the new serving cell SCell. That is, switching between the serving cell SCell #2 and the candidate cell #2-1 is performed.

[0066] [Serving Cell Switch Example 2] The RRC / MAC CE can configure a global candidate cell ID (cell #0,...,8) for each cell group, band, FR, and UE. The UE may be instructed to switch serving cells by the global candidate cell ID.

[0067] 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.

[0068] For example, in the serving cell SpCell #0 of the MCG / SCG, when L1 / L2 signaling indicates that the candidate cell #4 is to be changed to a serving cell (e.g., SpCell), the candidate cell #4 becomes the new serving cell SpCell. That is, switching between the serving cell SpCell #0 and the candidate cell #4 is performed.

[0069] The UE may receive an instruction to change the serving cell (here, switching between the serving cell SPCell#0 and the candidate cell#4) via the MAC CE / DCI, and may determine that the indicated candidate cell#4 will be the SpCell of the new cell group.

[0070] 6 is a diagram showing a serving cell switch example 3. This example shows a case where cell group switching is instructed by L1 / L2 signaling.

[0071] The UE receives an instruction to change the serving cell (here, switching between the cell group including SpCell #0 / #1 / #2 and the cell group including candidate cells #0 / #1 / #2) via MAC CE / DCI. Then, a predetermined cell (here, candidate cell #0) included in the switching destination cell group becomes the serving cell SpCell. Here, a case has been shown in which the predetermined cell becomes a candidate cell corresponding to the same frequency as the SpCell, but this is not limiting. A predetermined cell may also be indicated.

[0072] Furthermore, candidate cells (here, candidate cell #1 and candidate cell #2) included in the same cell group as candidate cell #0 become SCells. That is, the serving cell group and candidate cell group are switched by L1 / L2 signaling.

[0073] (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.

[0074] 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.

[0075] The UE may control the timing of UL transmission by applying timing advance (multiple timing advances) for each pre-configured timing advance group (TAG).

[0076] 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.

[0077] 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.

[0078] 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).

[0079] 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).

[0080] 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.

[0081] 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).

[0082] 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.

[0083] 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.

[0084] 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.

[0085] (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.

[0086] FIG. 10 is a diagram showing an example of TAG settings for multiple cells (or TRPs) with different PCIs.

[0087] 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.

[0088] 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).

[0089] 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.

[0090] (TA Acquisition) It is also possible that the UE performs UL transmission of a candidate cell in consideration of the TA corresponding to the candidate cell. When considering the TA of the candidate cell, the UE needs to acquire the TA of the candidate cell (for example, TA acquisition of candidate cells).

[0091] For TA acquisition of a candidate cell, several TA acquisition methods are possible, such as TA acquisition using RACH (e.g., RACH-based solutions) and TA acquisition without using RACH (RACH-less solutions). For TA acquisition using RACH, a method with RAR monitoring and a method without RAR monitoring may be supported. The TA acquisition method may be interpreted as a TA acquisition scheme, a TA acquisition type, or a TA acquisition procedure. In the present disclosure, TA acquisition, TA measurement, TA calculation, TA computation, and TA determination may be interpreted as interchangeable terms.

[0092] 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).

[0093] 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).

[0094] 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.

[0095] 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.

[0096] 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.

[0097] (Maintenance of Uplink Time Alignment) Parameters such as a time alignment timer (e.g., timeAlignmentTimer) may be configured for the maintenance of UL time alignment. The time alignment timer (per TAG) may control the time at which the MAC entity considers the serving cells belonging to the associated TAG to be UL time aligned.

[0098] 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.

[0099] 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.

[0100] The MAC entity receives a MAC CE for a timing advance command and synchronizes the MAC CE with the indicated TAG by a predetermined value (N ＴＡ ) is maintained, apply a timing advance command for the indicated TAG and start or restart the time alignment timer associated with the indicated TAG. ＴＡ ) may be the timing advance between DL and UL.

[0101] When a timing advance command is received in an RAR message for a serving cell belonging to a TAG (e.g., a TAG of an SpCell) or in a message B (e.g., MSGB) for the SpCell, if the MAC entity does not select a random access preamble from among the collision-based random access preambles, it may apply the timing advance command for that TAG and may also start or restart the time alignment timer associated with that TAG.

[0102] The timing advance command of the PTAG may be applied if an absolute timing advance command (e.g., Absolute Timing Advance Command) is received in response to transmitting a message A (e.g., MSGA) containing a given RNTI MAC CE (e.g., C-RNTI MAC CE).

[0103] 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).

[0104] 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.

[0105] For example, when the time alignment timer expires, the following actions (e.g., predetermined PTAG action / predetermined STAG action) may be performed.

[0106] 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.

[0107] 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.

[0108] (Timing Advance Reporting) A timing advance reporting procedure (e.g., Timing Advance Reporting (TAR)) may be performed to provide the base station with an estimate of the UE's timing advance value. The RRC may configure the parameters / conditions for the timing advance report. The timing advance report may be triggered when a predetermined event occurs.

[0109] The specified event may be, for example, at least one of the following: when an instruction to trigger a timing advance report is received from a higher layer; when a specified parameter (e.g., an offset threshold TA) is set by a higher layer; or when the variation between the current estimate of the timing advance value and the last reported timing advance value is greater than or equal to the specified parameter.

[0110] The UE (or MAC entity) may report timing advance using a predetermined MAC CE (e.g., a timing advance report MAC CE). Even if multiple events trigger timing advance reporting, a MAC PDU may contain at most one timing advance report MAC CE. When a MAC PDU is transmitted and contains a timing advance report MAC CE, all triggered timing advance reports may be canceled.

[0111] 11 shows an example of a Timing Advance Report MAC CE, which may have a fixed size and may consist of two octets.

[0112] (Overview of L1L2-triggered mobility (LTM)) In L1L2-triggered mobility (LTM) supported in Rel. 18 and later, L1 inter-frequency measurements (e.g., L1 inter-frequency measurements) may be supported. Also, DL synchronization / UL synchronization of a candidate cell based on at least SSB before a cell switch command may be supported.

[0113] 12 is a diagram showing an overview of L1L2-triggered mobility (LTM). LTM and L1 / L2 inter-cell mobility may be interpreted as interchangeable.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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).

[0118] 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.

[0119] 13 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.

[0120] 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.

[0121] 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).

[0122] 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.

[0123] Fig. 14 is a diagram showing an example of a PDCCH ordered RACH without RAR monitoring. Only the differences between Fig. 14 and Fig. 13 will be described.

[0124] In the example of Fig. 14, 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 information about TA (e.g., TA indication) to the UE using a cell switch command.

[0125] 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.

[0126] FIG. 15 is a diagram illustrating an example of UE-based TA measurement.

[0127] The source cell may transmit, to the UE, information regarding the configuration of the candidate cell (e.g., candidate cell configuration information). The source cell may also transmit, to the UE, information regarding the candidate cell to which the UE-based TA measurement is applied (or the candidate cell for which the UE-based TA measurement is configured).

[0128] The source cell may send information / signaling to the UE to trigger / instruct UE-based TA measurements, which may be triggered by MAC CE / DCI.

[0129] When the UE receives information / signaling triggering / instructing UE-based TA measurement, the UE may measure the difference / difference in the reception timing of DL signals from multiple cells (or two cells) to obtain the TA of the candidate cell. For example, the UE may measure / calculate the difference / difference in the reception timing of DL signals between a reference cell (or a reference cell) and a candidate cell. Information about the reference cell / candidate cell may be indicated to the UE. As an example, the reference cell may be a source cell (or a serving cell).

[0130] The UE may perform UE-based TA measurements autonomously without receiving any information / signaling that triggers / instructs UE-based TA measurements.

[0131] When a reference cell (e.g., a source cell / a serving cell / a specific candidate cell) and a candidate cell are not synchronized, the UE may apply a predetermined offset parameter when acquiring the TA between the reference cell and the candidate cell. The predetermined offset parameter may be configured in the UE by a higher layer configuration (e.g., an RRC configuration).

[0132] Then, 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. After the cell switch, the UE may control UL transmission based on the TA acquired by the UE-based TA measurement.

[0133] (Analysis) As described above, in L1 / L2-based mobility (e.g., LTM) supported in Rel. 18 and later, it is assumed that TA acquisition of a candidate cell is supported before a cell switch command.

[0134] It is also assumed that UE-based TA measurement is configured / supported for TA acquisition. The UE-based TA measurement acquires the TA based on the timing difference of DL signals between cells (e.g., between a candidate cell and a reference cell), but the acquired TA may not always be appropriate. In such cases, the question arises as to how to determine the validity of the TA acquired by the UE through the UE-based TA measurement, for example, whether the network / UE determines the validity of the TA acquired through the UE-based TA measurement.

[0135] Below, analyses 1 to 8 explain possible considerations for UE / network behavior based on TA availability.

[0136] [Analysis 1] First of all, regarding the validity of a TA, it is not clear what it means for a TA to be invalid (not valid) (the definition of an invalid TA).

[0137] [Analysis 2] It is not clear when a report of a TA obtained by UE-based TA measurement is triggered (TA report timing).

[0138] [Analysis 3] The TA may become invalid after a certain period of time. When the TA becomes invalid, it is not clear what action the UE should take.

[0139] [Analysis 4] It is also assumed that the validity of the TA is determined by the network. In this case, it is not clear how the UE determines (recognizes) the validity of the determined TA. Furthermore, it is not clear what action the UE should take depending on the validity (valid / invalid) of the TA.

[0140] [Analysis 5] If the acquired TA is deemed valid by the UE, and TA acquisition / measurement is triggered by the network, it is not clear what action the UE should take.

[0141] [Analysis 6] When UE-based TA measurement is in progress, it is not clear what action the UE should take if TA acquisition / measurement is triggered by the network.

[0142] [Analysis 7] When the configuration related to TA acquisition is different, it is not clear how the TA acquired by UE-based TA measurement is indicated to the UE.

[0143] [Analysis 8] If the UE already has (acquired) a TA of the indicated candidate cell, and the TA is indicated by the cell switch command MAC CE, it is unclear what action the UE should take.

[0144] In this way, if the validity / appropriateness of the TA obtained by UE-based TA measurement is not properly determined, or if the behavior of the UE / network after determining the validity of the TA is not clear, timing advance control may not be performed properly (for example, the TA value to be applied to UL transmission may not be properly determined), which may result in a decrease in throughput / deterioration of communication quality.

[0145] Therefore, the present inventors have studied L1 / L2-based mobility (e.g., LTM) / cell switching operations when UE-based TA measurements are configured / supported, and have come up with an aspect of this embodiment.

[0146] 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.

[0147] (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."

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] In the present disclosure, physical layer signaling may be, for example, Downlink Control Information (DCI), Uplink Control Information (UCI), and the like.

[0153] 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.

[0154] 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.

[0155] In the following embodiments, a candidate cell index and a candidate config index may be interchangeable. Furthermore, TAG may be interchangeable with PTAG or STAG. A timer associated with a corresponding candidate cell index may be interchangeable with a timer of a TAG associated with the corresponding candidate cell index. A serving cell may be interchangeable with a special cell (e.g., SPCell). A candidate cell may include a current serving cell. A target cell may be interchangeable with a candidate cell / SpCell. TA may be interchangeable with TAG / TAC. A target cell index may be indicated by a cell switch command MAC CE.

[0156] (Wireless Communication Method) <Tenth Embodiment> [Option 1] Option 1 relates to UE operation when UE-based TA measurement is configured / supported.

[0157] Fig. 16 is a diagram showing an example of a cell switching operation when UE-based TA measurement is configured / supported. Note that the operation shown in Fig. 16 is an example, and the present embodiment is not limited to this.

[0158] The source cell may transmit information about the configuration of candidate cells (e.g., candidate cell configuration information) to the UE. The information about the configuration of candidate cells may be configured by a predetermined higher layer parameter (e.g., LTM-CandidateConfig). The information about the configuration of candidate cells may include information about TA acquisition applied to each candidate cell. For example, the information about candidate cells for which UE-based TA measurements are configured may be included.

[0159] The source cell may send information / signaling to the UE to trigger / instruct UE-based TA measurements, which may be triggered by MAC CE / DCI.

[0160] When the UE receives information / signaling triggering / instructing UE-based TA measurement, the UE may measure the difference / difference in the reception timing of DL signals from multiple cells (or two cells) to obtain the TA of the candidate cell. For example, the UE may measure / calculate the difference / difference in the reception timing of DL signals between a reference cell (or a reference cell) and a candidate cell. Information about the reference cell / candidate cell may be indicated to the UE. As an example, the reference cell may be a source cell (or a serving cell).

[0161] When a reference cell (e.g., a source cell / a serving cell / a specific candidate cell) and a candidate cell are not synchronized, the UE may apply a predetermined offset parameter when acquiring the TA between the reference cell and the candidate cell. The predetermined offset parameter may be configured in the UE by a higher layer configuration (e.g., an RRC configuration).

[0162] Note that the source cell may not transmit information / signaling to trigger / instruct the UE-based TA measurement to the UE, in which case the UE may autonomously perform the UE-based TA measurement based on higher layer parameters that instruct the configuration of the UE-based TA measurement.

[0163] When the UE acquires the TA based on the UE-based TA measurement, the UE may transmit predetermined signaling (or information) to the source cell (or reference cell) / target cell (or candidate cell).

[0164] The predetermined signaling (or information) may be applied to determining / notifying the reliability (or validity / appropriateness) of the TA obtained by the UE-based TA measurement. For example, when the validity of the TA obtained by the UE-based TA measurement is determined based on other conditions / rules, the reliability (or whether it is valid or not) of the TA may be notified by the predetermined signaling (or information).

[0165] The UE / network (or base station) may determine / notify the reliability (or validity / appropriateness) of the TA acquired by the UE-based TA measurement based on predetermined signaling. The predetermined signaling (or information) may be transmitted using MAC CE / UCI / PUCCH / PUSCH.

[0166] It should be noted that the predetermined signaling (or information) may not be transmitted.

[0167] Next, the source cell may transmit a cell switch command to the UE. TA information (e.g., information on the validity / appropriateness of the TA acquired by the UE-based TA measurement) may be transferred / notified from the source cell to the target cell. After the cell switch, the UE may control UL transmission based on the TA acquired by the UE-based TA measurement that is determined to be valid / appropriate.

[0168] In Fig. 16, when the UE acquires (e.g., calculates / measures) the TA by UE-based TA measurement, the UE may apply at least one of the following options 1-1 to 1-4 (e.g., singly or in combination). At least one of options 1-1 to 1-4 may be performed using predetermined signaling (or information).

[0169] [Option 1-1] The UE may report information about the TA (for example, the TA value) acquired by the UE-based TA measurement to the network using predetermined signaling (or information).

[0170] The predetermined signaling may be a UCI / MAC CE (or a PUCCH / PUSCH). For example, the UE may report the TA value using a timing advance report MAC CE.

[0171] The network may be a current serving cell / SpCell / candidate cell (e.g., a candidate cell that is not a serving cell). For example, the UE may report information about TA to at least one of the current serving cell, the SpCell, and a candidate cell (e.g., a candidate cell that is not a serving cell).

[0172] The validity of the TA acquired by the UE-based TA measurement may be determined / notified by the TA reported from the UE to the network. For example, if the UE determines that the TA acquired by the UE-based TA measurement is valid, the TA may be reported to the network to notify that the TA is valid. Furthermore, when the validity of the TA is determined on the network side, the validity of the TA may be determined based on information about the reported TA (e.g., TA value).

[0173] [Option 1-2] The UE may transmit an acknowledgement signal / other indication to the network in response to the signaling / information that triggers / instructs UE-based TA measurements. The acknowledgement signal / other indication may be transmitted using UCI / MAC CE.

[0174] The UE may be controlled to transmit an acknowledgement signal / other instruction within a predetermined time (e.g., during a certain time) after receiving the signaling that triggers / instructs UE-based TA measurements. The predetermined time may be defined in the specification or configured by the RRC / MAC CE.

[0175] The delivery confirmation signal (eg, HARQ-ACK) may be an ACK or a NACK.

[0176] The network may be the current serving cell / SpCell / candidate cell (e.g., a candidate cell that is not the serving cell). For example, the UE may send an acknowledgement signal / other indication for the signaling that triggers the UE-based TA measurement to at least one of the current serving cell, the SpCell, and a candidate cell (e.g., a candidate cell that is not the serving cell).

[0177] The validity of the TA acquired by the UE-based TA measurement may be determined / notified by a delivery acknowledgement signal / other instruction in response to trigger / instruction signaling transmitted from the UE. For example, if the UE determines that the TA acquired by the UE-based TA measurement is valid, the UE may be notified that the TA is valid / invalid by the delivery acknowledgement signal / other instruction. Furthermore, when the network side determines the validity of the TA, the validity of the TA may be determined based on the content of the transmitted delivery acknowledgement signal / other instruction.

[0178] [Option 1-3] The UE may request starting / stopping of a predetermined timer (for example, a time alignment timer) associated with the TA acquired by the UE-based TA measurement.

[0179] For example, the UE may transmit predetermined signaling (or information) to the network requesting start / stop of the predetermined timer. The predetermined signaling may be UCI / MAC CE (or PUCCH / PUSCH). The network may be at least one of the current serving cell, the SpCell, and a candidate cell (e.g., a candidate cell that is not the serving cell).

[0180] The validity of the TA acquired by the UE-based TA measurement may be determined / notified by a start / stop request of a predetermined timer transmitted from the UE. For example, if the UE determines that the TA acquired by the UE-based TA measurement is valid, the UE may be notified that the TA is valid / invalid by a start / stop request of a predetermined timer. Furthermore, when the validity of the TA is determined on the network side, the validity of the TA may be determined based on the start / stop request of the predetermined timer.

[0181] [Option 1-4] When the UE acquires the TA through UE-based TA measurement, the UE may be controlled to do nothing (for example, not to transmit predetermined signaling (or information)).

[0182] In Option 1-1 to Option 1-4, the UE may indicate / report information about candidate cells associated with the TA acquired by the UE-based TA measurement to the network. The information about candidate cells associated with the TA acquired by the UE-based TA measurement may be included in predetermined signaling or in any UCI / MAC CE (or PUCCH / PUSCH) transmitted by the UE.

[0183] In this way, the validity of the TA acquired by the TA measurement may be determined / notified based on predetermined signaling reported / transmitted from the UE to the network, thereby enabling the TA acquired by the TA measurement to be used appropriately.

[0184] At least one of Option 1-1 to Option 1-4 may be applied to the following Case 1-1 (Case 1-1A / B), Case 1-2 (Case 1-2A / B), and Case 1-3 (Case 1-3A / B), respectively.

[0185] [Case 1-1] Case 1-1 corresponds to the case where the TA acquired by the UE-based TA measurement is valid.

[0186] Whether the TA acquired by the UE-based TA measurement is valid may be determined based on a predetermined rule / condition. For example, whether the TA acquired by the UE-based TA measurement is valid may be determined by the UE / network based on a predetermined rule / condition.

[0187] <Case 1-1A> In a case where a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are synchronized, at least one of the above Option 1-1, Option 1-2, Option 1-3, and Option 1-4 (e.g., alone or in combination) may be applied.

[0188] For example, the UE may report information about the TA (e.g., the TA value) obtained by UE-based TA measurement to the network using predetermined signaling (e.g., timing advance report MAC CE / UCI) (option 1-1).

[0189] The UE may send an ACK / other indication to the network in response to the signaling / information triggering / instructing UE-based TA measurement (option 1-2). The ACK / other indication may be sent by the UCI / MAC CE. The UE may send the ACK and perform UE-based TA measurement. The network (e.g., base station) may determine that the TA obtained by the UE-based TA measurement is valid based on the ACK / other indication sent from the UE.

[0190] The UE may request the start of a predetermined timer (e.g., a time alignment timer) associated with the TA acquired by the UE-based TA measurement (options 1-3). The request to start the predetermined timer (e.g., a time alignment timer) may be made by the UCI / MAC CE.

[0191] The UE may be controlled to do nothing (e.g., not transmit predetermined signaling (or information)) when acquiring the TA through the UE-based TA measurement (Option 1-4). In this case, not doing anything (e.g., not transmitting predetermined signaling (or information)) may mean that the TA acquired through the UE-based TA measurement is valid.

[0192] <Case 1-1B> In the case where a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are asynchronous, at least one of Option 1-1, Option 1-2, Option 1-3, and Option 1-4 (e.g., alone or in combination) may be applied.

[0193] For example, the UE may report information about the TA (e.g., the TA value) obtained by UE-based TA measurement to the network using predetermined signaling (e.g., timing advance report MAC CE / UCI) (option 1-1).

[0194] The UE may send an ACK / other indication to the network in response to the signaling / information that triggers / instructs UE-based TA measurement (option 1-2). The ACK / other indication may be sent by the UCI / MAC CE. The network (e.g., base station) may determine that the TA acquired by the UE-based TA measurement is valid based on the ACK / other indication sent from the UE.

[0195] The UE may request the start of a predetermined timer (e.g., a time alignment timer) associated with the TA acquired by the UE-based TA measurement (options 1-3). The request to start the predetermined timer (e.g., a time alignment timer) may be made by the UCI / MAC CE.

[0196] The UE may be controlled to do nothing (e.g., not transmit predetermined signaling (or information)) when acquiring the TA through the UE-based TA measurement (Option 1-4). In this case, not doing anything (e.g., not transmitting predetermined signaling (or information)) may mean that the TA acquired through the UE-based TA measurement is valid.

[0197] Alternatively, the UE may not assume Case 1-1B. That is, when the first cell (e.g., source / reference cell) and the second cell (e.g., target / candidate cell) are asynchronous, the TA acquired by the UE-based TA measurement may always be determined to be invalid (not valid).

[0198] In Case 1-1A / 1-1B, the UE may report a difference value between DL reference timings (e.g., a difference value between the reception timings of DL signals between a reference cell and a candidate cell), and the network may determine whether or not the cells are synchronized. In this case, the network may instruct the UE to perform a predetermined operation (e.g., at least one of Option 1-1 to Option 1-4) by any DCI / MAC CE.

[0199] [Case 1-2] Case 1-2 corresponds to a case where the TA acquired by the UE-based TA measurement is invalid (not valid).

[0200] Whether the TA acquired by the UE-based TA measurement is invalid may be determined based on a predetermined rule / condition. For example, whether the TA acquired by the UE-based TA measurement is invalid may be determined by the UE / network based on a predetermined rule / condition.

[0201] <Case 1-2A> In a case where a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are synchronized, at least one of Option 1-1, Option 1-2, Option 1-3, and Option 1-4 (e.g., alone or in combination) may be applied.

[0202] For example, the UE may report information about the TA (e.g., the TA value) obtained by UE-based TA measurement to the network using predetermined signaling (e.g., timing advance report MAC CE / UCI) (option 1-1).

[0203] The UE may send a NACK / other indication to the network in response to the signaling / information that triggers / instructs UE-based TA measurement (option 1-2). The NACK / other indication may be transmitted by the UCI / MAC CE. When the UE transmits a NACK, the UE may perform UE-based TA measurement or may control the UE not to perform UE-based TA measurement. The network (e.g., a base station) may determine that the TA acquired by the UE-based TA measurement is invalid (or not valid) based on the NACK / other indication transmitted from the UE. In this case, the base station may control the UE to perform another TA acquisition (e.g., RACH-based TA acquisition or PDCCH order transmission).

[0204] The UE may request the stopping of a predetermined timer (e.g., a time alignment timer) associated with the TA acquired by the UE-based TA measurement (options 1-3). The request to stop the predetermined timer (e.g., a time alignment timer) may be made by the UCI / MAC CE.

[0205] The UE may be controlled to do nothing (e.g., not transmit predetermined signaling (or information)) when acquiring a TA through UE-based TA measurement (Option 1-4). In this case, not doing anything (e.g., not transmitting predetermined signaling (or information)) may mean that the TA acquired through UE-based TA measurement is invalid (or not valid).

[0206] Alternatively, the UE may not assume Case 1-2A, i.e., when a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are synchronized, the TA obtained by the UE-based TA measurement may always be determined to be valid.

[0207] <Case 1-2B> In the case where a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are asynchronous, at least one of Option 1-1, Option 1-2, Option 1-3, and Option 1-4 (e.g., alone or in combination) may be applied.

[0208] For example, the UE may report information about the TA (e.g., the TA value) obtained by UE-based TA measurement to the network using predetermined signaling (e.g., timing advance report MAC CE / UCI) (option 1-1).

[0209] The UE may send a NACK / other indication to the network in response to the signaling / information that triggers / instructs UE-based TA measurement (option 1-2). The NACK / other indication may be transmitted by the UCI / MAC CE. When the UE transmits a NACK, the UE may perform UE-based TA measurement or may control the UE not to perform UE-based TA measurement. The network (e.g., a base station) may determine that the TA acquired by the UE-based TA measurement is invalid (or not valid) based on the NACK / other indication transmitted from the UE. In this case, the base station may control the UE to perform another TA acquisition (e.g., RACH-based TA acquisition or PDCCH order transmission).

[0210] The UE may request the stopping of a predetermined timer (e.g., a time alignment timer) associated with the TA acquired by the UE-based TA measurement (options 1-3). The request to stop the predetermined timer (e.g., a time alignment timer) may be made by the UCI / MAC CE.

[0211] The UE may be controlled to do nothing (e.g., not transmit predetermined signaling (or information)) when acquiring a TA through UE-based TA measurement (option 1-4). In this case, not doing anything (e.g., not transmitting predetermined signaling (or information)) may mean that the TA acquired through UE-based TA measurement is invalid (or not valid).

[0212] In Case 1-2A / 1-2B, the UE may report a difference value between DL reference timings (e.g., a difference value between the reception timings of DL signals between a reference cell and a candidate cell), and the network may determine whether the cells are synchronized. In this case, the network may instruct the UE to perform a predetermined operation (e.g., at least one of Option 1-1 to Option 1-4) by any DCI / MAC CE.

[0213] [Case 1-3] Case 1-3 corresponds to a case where it is not clear to the UE whether the TA obtained by UE-based TA measurement is valid (or a case where the UE cannot determine whether the TA obtained by UE-based TA measurement is valid).

[0214] Whether the TA acquired by the UE-based TA measurement is valid or not may be determined based on a predetermined rule / condition. For example, whether the TA acquired by the UE-based TA measurement is valid / invalid may be determined on the network side based on a predetermined rule / predetermined condition / a report from the UE, etc.

[0215] <Case 1-3A> In a case where a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are synchronized, at least one of Option 1-1, Option 1-2, Option 1-3, and Option 1-4 (e.g., alone or in combination) may be applied.

[0216] For example, the UE may report information about the TA (e.g., the TA value) obtained by UE-based TA measurement to the network using predetermined signaling (e.g., timing advance report MAC CE / UCI) (option 1-1).

[0217] The UE may send a NACK / other indication to the network in response to the signaling / information that triggers / instructs UE-based TA measurement (option 1-2). The NACK / other indication may be sent by the UCI / MAC CE. The network (e.g., a base station) may determine whether the TA acquired by the UE-based TA measurement is valid based on the NACK / other indication sent from the UE. In this case, the base station may notify the UE of the determination result (e.g., that the TA acquired by the UE-based TA measurement is valid). Note that NACK may be replaced with ACK.

[0218] The UE may request the stopping of a predetermined timer (e.g., a time alignment timer) associated with the TA acquired by the UE-based TA measurement (options 1-3). The request to stop the predetermined timer (e.g., a time alignment timer) may be made by the UCI / MAC CE.

[0219] The UE may be controlled to do nothing (for example, not transmit predetermined signaling (or information)) when acquiring a TA through UE-based TA measurement (Option 1-4). In this case, not doing anything (for example, not transmitting predetermined signaling (or information)) may mean that it is unclear on the UE side whether the TA acquired through UE-based TA measurement is valid (or the UE side cannot determine whether the TA is valid).

[0220] Alternatively, the UE may not assume Cases 1-3A, i.e., when a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are synchronized, the TA obtained by the UE-based TA measurement may always be determined to be valid.

[0221] <Case 1-3B> In the case where a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are asynchronous, at least one of Option 1-1, Option 1-2, Option 1-3, and Option 1-4 (e.g., alone or in combination) may be applied.

[0222] For example, the UE may report information about the TA (e.g., the TA value) obtained by UE-based TA measurement to the network using predetermined signaling (e.g., timing advance report MAC CE / UCI) (option 1-1).

[0223] The UE may send a NACK / other indication to the network in response to the signaling / information that triggers / instructs UE-based TA measurement (option 1-2). The NACK / other indication may be sent by the UCI / MAC CE. The network (e.g., a base station) may determine whether the TA acquired by the UE-based TA measurement is valid based on the NACK / other indication sent from the UE. In this case, the base station may notify the UE of the determination result (e.g., that the TA acquired by the UE-based TA measurement is valid). Note that NACK may be replaced with ACK.

[0224] The UE may request the stopping of a predetermined timer (e.g., a time alignment timer) associated with the TA acquired by the UE-based TA measurement (options 1-3). The request to stop the predetermined timer (e.g., a time alignment timer) may be made by the UCI / MAC CE.

[0225] The UE may be controlled to do nothing (for example, not transmit predetermined signaling (or information)) when acquiring a TA through UE-based TA measurement (Option 1-4). In this case, not doing anything (for example, not transmitting predetermined signaling (or information)) may mean that it is unclear on the UE side whether the TA acquired through UE-based TA measurement is valid (or the UE side cannot determine whether the TA is valid).

[0226] Alternatively, the UE may not assume Cases 1-3B, i.e., when the first cell (e.g., source / reference cell) and the second cell (e.g., target / candidate cell) are asynchronous, the TA acquired by the UE-based TA measurement may always be determined to be invalid (not valid).

[0227] In Case 1-3A / 1-3B, the UE may report a difference value between DL reference timings (e.g., a difference value between the reception timings of DL signals between a reference cell and a candidate cell), and the network may determine whether or not the cells are synchronized. In this case, the network may instruct the UE to perform a predetermined operation (e.g., at least one of Option 1-1 to Option 1-4) by any DCI / MAC CE.

[0228] [Option 2] Option 2 relates to an example of a method for determining whether a TA acquired by UE-based TA measurement is valid. Option 2 may be applied in combination with the above-mentioned cases / options. Note that the determination of TA validity in Option 2 may be applied only at the timing when the UE calculates / measures the TA.

[0229] Whether the TA acquired by the UE-based TA measurement is valid may be determined by at least one of the network (e.g., base station) and the UE. Whether the TA acquired by the UE-based TA measurement is valid may be determined based on a predetermined rule / predetermined condition. At least one of the UE and the network (e.g., base station) may determine whether the TA acquired by the UE-based TA measurement is valid based on a predetermined rule / predetermined condition.

[0230] As a method for determining whether the TA obtained by UE-based TA measurement is valid, at least one of the following options 2-1 to 2-2 may be applied.

[0231] Each option may be applied to a case where the first cell (e.g., source / reference cell) and the second cell (e.g., target / candidate cell) are synchronized, and a case where the first cell (e.g., source / reference cell) and the second cell (e.g., target / candidate cell) are asynchronous. The same option may be applied to the synchronized case and the asynchronous case, or different options may be applied.

[0232] [Option 2-1] Whether the TA obtained by UE-based TA measurement is valid may be determined by the network (for example, a base station).

[0233] The network (e.g., a base station) may determine whether the TA obtained by the UE-based TA measurement is valid based on at least one of predetermined rules, predetermined conditions, and reports / signaling from the UE.

[0234] For example, a network (e.g., a base station) may determine the validity of a TA based on information about the TA reported from a UE (e.g., a TA value obtained by UE-based TA measurement). For example, if the TA value is equal to or greater than a predetermined threshold, the base station may determine that the TA obtained by UE-based TA measurement is valid.

[0235] For example, the network (e.g., a base station) may send signaling instructing the triggering of UE-based TA measurements and determine the validity of the TA based on signals in response to the signaling (e.g., delivery confirmation signals / other signals).

[0236] For example, the network (e.g., a base station) may determine that the TA obtained by UE-based TA measurement is not valid if the first cell (e.g., a source / reference cell) and the second cell (e.g., a target / candidate cell) are asynchronized.

[0237] The network (e.g., base station) may determine that the TA obtained by the UE-based TA measurement is valid if the first cell (e.g., source / reference cell) and the second cell (e.g., target / candidate cell) are synchronized. Alternatively, the network (e.g., base station) may determine whether the TA obtained by the UE-based TA measurement is valid based on other conditions / reports from the UE, etc., if the first cell (e.g., source / reference cell) and the second cell (e.g., target / candidate cell) are synchronized.

[0238] Whether or not the TA obtained by UE-based TA measurement is valid may be determined based on the synchronization state between the first cell (e.g., source / reference cell) and the second cell (e.g., target / candidate cell), or may be determined based on other conditions regardless of the synchronization state.

[0239] As mentioned above, if the validity of the TA is determined by the network, a timer may be configured to control the validity duration. For example, the timer may be started when the network instructs the UE to perform UE-based TA measurements. If the timer expires, the UE may perform UE-based TA measurements again without network instruction.

[0240] For example, if the network determines that the TA is invalid (not valid), the network may stop the timer. If the network cannot recognize the validity of the TA value, the network may not stop the timer. Note that the timer will be described in later embodiments (e.g., the first and second embodiments).

[0241] [Option 2-2] Whether the TA obtained by UE-based TA measurement is valid may be determined by the UE.

[0242] The UE may determine whether the TA acquired by the UE-based TA measurement is valid based on at least one of a predetermined rule and a predetermined condition. For example, the predetermined rule and / or the predetermined condition may be the content of the UE-based TA measurement (e.g., the timing difference of the DL signal between the candidate cells, the calculated / measured TA value, etc.), or may be other rules / conditions. The UE may use at least one of the following options 2-2-1 to 2-2-4.

[0243] <<Option 2-2-1>> The UE may determine whether the TA is valid based on the results (e.g., TA value) calculated / measured by the UE-based TA measurement.

[0244] For example, if the TA value calculated / measured by the UE-based TA measurement is equal to or greater than a predetermined threshold, the UE may determine that the TA obtained by the UE-based TA measurement is valid. The predetermined threshold may be a value set by DCI / MAC CE / RRC, a value defined in a specification, or a value determined based on UE capabilities (e.g., UE capability).

[0245] If the TA value calculated / measured by the UE-based TA measurement is less than a predetermined threshold, the UE may determine that the TA obtained by the UE-based TA measurement is invalid (or not valid).

[0246] Alternatively, if the TA value calculated / measured by the UE-based TA measurement is equal to or greater than a predetermined threshold, the UE may determine that the TA obtained by the UE-based TA measurement is invalid (or ineffective). Also, if the TA value calculated / measured by the UE-based TA measurement is less than a predetermined threshold, the UE may determine that the TA obtained by the UE-based TA measurement is effective.

[0247] In addition, if the TA measured by the UE becomes invalid (is not valid), the UE may perform UE-based TA measurement and update the TA value.

[0248] <<Option 2-2-2>> The UE may determine that the TA is valid if the TA value can be obtained by UE-based TA measurement (e.g., the TA value can be calculated / measured). In other words, if the UE can obtain the TA value by UE-based TA measurement, the UE may always determine that the TA is valid regardless of the calculation / measurement result.

[0249] <<Option 2-2-3>> The UE may determine whether the TA is valid based on the maximum value of the timing difference of UL transmission between candidate cells (for example, the maximum uplink transmission timing difference).

[0250] For example, if the maximum value of the timing difference of UL transmission between the candidate cells (or the maximum timing difference of UL transmission between the candidate cells) is greater than / exceeds a predetermined threshold, the UE may determine that the TA obtained by the UE-based TA measurement is invalid (or not valid). The predetermined threshold may be a value set by DCI / MAC CE / RRC, a value defined in a specification, or a value determined based on UE capabilities (e.g., UE capability).

[0251] The UE may obtain the maximum value of the timing difference of UL transmission between candidate cells (or the maximum timing difference of UL transmission between candidate cells) based on the content of the UE-based TA measurement (e.g., a TA value obtained by calculation / measurement, the timing difference of DL signals between cells, etc.). Alternatively, the UE may be notified of the maximum value of the timing difference of UL transmission between candidate cells (or the maximum timing difference of UL transmission between candidate cells) by the base station.

[0252] <<Option 2-2-4>> The UE may determine whether TA is valid based on the difference between DL reference timings (e.g., difference between DL reference timings). The difference between DL reference timings may be the difference in timing at which DL signals transmitted from each candidate cell (e.g., source / reference cell, target / candidate cell) are received.

[0253] For example, if the difference between the DL reference timings is greater than / exceeds a predetermined threshold, the UE may determine that the TA obtained by the UE-based TA measurement is invalid (or not valid). The predetermined threshold may be a value configured by DCI / MAC CE / RRC, a value defined in a specification, or a value determined based on the UE capability (e.g., UE capability).

[0254] At least one of Options 2-2-1 to 2-2-3 may be applied to a case where a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are synchronized, and at least one of Options 2-2-1 to 2-2-4 may be applied to a case where they are asynchronous. That is, Option 2-2-4 may be applied only to the asynchronous case. Of course, the applicable cases are not limited to this.

[0255] [Synchronization / Asynchronous Between Candidate Cells] Whether multiple candidate cells are synchronized or asynchronous may be determined based on a predetermined rule / predetermined condition. The multiple candidate cells may include at least one (or both) of a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell). Whether multiple candidate cells are synchronized or asynchronous may be determined based on the following options 3-1 to 3-3. Options 3-1 to 3-3 may be applied in the 0th embodiment.

[0256] Option 3-1: Synchronization / asynchronous between cells may be determined based on a difference between DL reference timings. The difference between DL reference timings may be a difference in timing at which DL signals transmitted from each candidate cell (e.g., source / reference cell, target / candidate cell) are received.

[0257] For example, the UE / network may be determined to be unsynchronized (or out of sync) if the difference between the DL reference timings is greater / exceeds a predetermined threshold, which may be a value configured by the DCI / MAC CE / RRC, a value defined in a specification, or a value determined based on the UE capabilities (e.g., UE capability).

[0258] Option 3-2: A candidate cell that is not the serving cell may always be considered to be asynchronous with the current serving cell. The UE / network may assume / determine that a candidate cell that is not the serving cell is asynchronous with the current serving cell.

[0259] <<Option 3-3>> Synchronization / asynchronization among multiple candidate cells may be configured / instructed by DCI / MAC CE / RRC. The UE may determine synchronization / asynchronization among multiple candidate cells based on the configuration / instruction of DCI / MAC CE / RRC.

[0260] According to the 0th embodiment described above, the UE can appropriately determine the validity of the TA acquired by the UE-based TA measurement.

[0261] First Embodiment The first embodiment, in relation to the above-mentioned analyses 1 and 2, will explain the meaning (definition) of TA being invalid and the conditions under which a UE triggers a TA report.

[0262] In the above-described 0th embodiment, a case is described in which the validity of a TA is determined when the UE calculates / measures the TA. On the other hand, even if the acquired TA (at the time of measurement) is determined to be valid at that time, it is assumed that the valid TA may become invalid over time.

[0263] Therefore, in this embodiment, the validity of TA after a predetermined time has elapsed since measurement, that is, cases / conditions in which TA becomes invalid, will be described.

[0264] In the present disclosure, an invalid (not valid) TA may mean that the measured / obtained TA value itself is not an accurate value, whereas a valid TA may mean that the measured / obtained TA value itself is an accurate value.

[0265] Options 1 to 4 below relate to the validity of the TA (particularly the definition of invalidity).

[0266] [Option 1] A predetermined timer may be introduced to determine the validity of the TA. This timer may be called a time alignment timer. The UE / network may determine the validity of the TA based on the timer, which is the criteria for determining the validity of the TA. This timer may be associated with the TA / TAG / candidate cell configured / instructed by the RRC / MAC CE. If the timer expires, the TA becomes invalid. That is, the UE / network may determine that the TA is invalid if the timer expires.

[0267] [Option 2] A predetermined threshold may be introduced as a criterion for determining the validity of TA. The UE / network may determine the validity of TA based on the threshold. The threshold may be a value related to L1-RSRP / SINR. The threshold may also be set / indicated by RRC / MAC CE / DCI or may be predetermined by a specification.

[0268] 17 is a diagram showing an example of criteria for determining the validity of a TA according to Option 2. In Option 2, the threshold (certain value) may have a predetermined width (range).

[0269] For example, a TA may be invalid if the L1-RSRP / SINR associated with the candidate cell corresponding to the measured / obtained TA changes (increases or decreases) by a value greater than (a range of) the threshold, i.e., the UE / network may determine that a TA is invalid if the L1-RSRP / SINR associated with the measured / obtained TA changes significantly with respect to the threshold.

[0270] In other words, the UE / network may determine that a TA is valid even if the measured / obtained L1-RSRP / SINR associated with the TA changes over time, as long as the change does not exceed a threshold (range).

[0271] More specifically, as shown in FIG. 17, if the L1-RSRP / SINR associated with the measured / acquired TA falls outside the threshold range (below the lower limit of the threshold) at time Tc, the UE / network may determine that the TA is invalid (has become invalid).

[0272] In this case, the UE / network can determine that the TA is valid before time Tc, and can determine that the TA is invalid after time Tc. That is, time Tc is the timing at which the determination result regarding the validity of the TA switches.

[0273] 17, at a timing Td after time Tc, the corresponding L1-RSRP / SINR value changes to fall within the threshold range. In this case, the UE / network may determine that a TA that was once determined to be invalid is valid. In this way, by determining (updating) the validity of a TA based on a comparison between the change in the L1-RSRP / SINR value and the threshold, it is possible to flexibly control the determination of the validity of a TA.

[0274] Alternatively, even if the corresponding L1-RSRP / SINR value changes to within the threshold range at time Td after time Tc, the UE / network does not need to update the determination result of the TA that was once determined to be invalid (does not need to determine it as valid). By maintaining the result of the previous determination, it is possible to reduce the processing load and communication overhead of the UE / network. For example, when a sudden change in the L1-RSRP / SINR value is likely to occur, it is possible to reduce unnecessary processing load of the UE / network by uniformly fixing the determination result.

[0275] Specific examples of the criteria for options 2-1 to 2-4 will be described below with reference to FIG. 17. As described above, in option 2, the threshold may include a predetermined range from the criteria. FIG. 17 also shows the predetermined range (threshold) corresponding to the criteria for options 2-1 / 2-4.

[0276] <<Option 2-1>> The L1-RSRP / SINR value used as the criterion may be the measurement result (of L1-RSRP / SINR) at the timing of time Tm when TA is measured / acquired.

[0277] <<Option 2-2>> The L1-RSRP / SINR value used as the criterion may be the (latest) measurement result prior to the timing of time Tm when TA is measured / acquired.

[0278] <<Option 2-3>> The L1-RSRP / SINR value used as the criterion may be the (latest) measurement result after the timing of the time Tm when the TA is measured / acquired.

[0279] <<Option 2-4>> The L1-RSRP / SINR value used as the criterion may be the measurement result (of L1-RSRP / SINR) corresponding to the SSB used to calculate the TA.

[0280] The criteria for the above options 2-1 to 2-4 may be set / indicated by the RRC / MAC CE / DCI, may be predetermined by specifications, or may be predetermined based on UE capabilities.

[0281] [Option 3] A predetermined threshold may be introduced as a criterion for determining the validity of TA. The UE / network may determine the validity of TA based on the threshold. The threshold may be a value related to L1-RSRP / SINR. The threshold may also be set / indicated by RRC / MAC CE / DCI or may be predetermined by a specification.

[0282] 18 is a diagram showing an example of criteria for determining the validity of a TA according to Option 3. In Option 3, the threshold may indicate a certain value.

[0283] For example, if the L1-RSRP / SINR associated with the candidate cell corresponding to the measured / obtained TA falls below (is less than) the threshold, the TA may be invalid, i.e., the UE / network may determine that the TA is invalid if the L1-RSRP / SINR associated with the measured / obtained TA changes significantly to fall below the threshold.

[0284] In other words, the UE / network may determine that a TA is valid even if the measured / obtained L1-RSRP / SINR associated with the TA changes over time as long as the value does not fall below a threshold.

[0285] More specifically, as shown in FIG. 18, if the measured / acquired L1-RSRP / SINR associated with the TA becomes smaller than (below) a threshold at time Tc, the UE / network may determine that the TA is invalid (has become invalid).

[0286] In this case, the UE / network can determine that the TA is valid before time Tc, and can determine that the TA is invalid after time Tc. That is, time Tc is the timing when the determination result regarding the validity of the TA switches.

[0287] 18, at a timing Td after time Tc, the corresponding L1-RSRP / SINR value changes to exceed the threshold. In this case, the UE / network may determine that a TA that was once determined to be invalid is valid. In this way, by determining (updating) the validity of a TA based on a comparison between the change in the L1-RSRP / SINR value and the threshold, it is possible to flexibly control the determination of the validity of a TA.

[0288] Alternatively, even if the corresponding L1-RSRP / SINR value changes to exceed a threshold at time Td after time Tc, the UE / network does not need to update the determination result of the TA that was once determined to be invalid (does not need to determine it as valid). By maintaining the result of the previous determination, it is possible to reduce the processing load and communication overhead of the UE / network. For example, when a sudden change in the L1-RSRP / SINR value is likely to occur, it is possible to reduce unnecessary processing load of the UE / network by uniformly fixing the determination result.

[0289] [Option 4] In the above-mentioned Option 2 / 3, if multiple beams exist (are configured) for each candidate cell, the following Options 4-1 to 4-3 may be applied.

[0290] <<Option 4-1>> The L1-RSRP / SINR associated with the SSB used in calculating the TA may be referenced.

[0291] <<Option 4-2>> The L1-RSRP / SINR associated with any SSB of the corresponding candidate cell may be referenced.

[0292] <<Option 4-3>> The filtered / average L1-RSRP / SINR (values ​​averaged over time) by all SSBs of the corresponding candidate cell may be referenced.

[0293] Option 5 Option 5 relates to triggering TA reporting.

[0294] The UE may trigger a TA report based on at least one of the following options A to C:

[0295] <Option A> After UE-based TA measurement based on the configuration / instruction from the NW is completed, the UE may trigger a TA report.

[0296] Option B: After the UE determines the validity of the current TA (for example, when the UE moves or after a certain time has passed), the UE may trigger a TA report.

[0297] <Option C> Based on the configuration from the NW, the UE may trigger TA reporting periodically / non-periodically.

[0298] According to the first embodiment described above, the validity of a TA is determined clearly, and the UE can appropriately control TA reporting.

[0299] Second Embodiment The second embodiment will explain the validity of a TA (timer control when the TA becomes invalid) after a certain time has elapsed since the TA was acquired, in relation to the above-described Analysis 3. In the second embodiment, a case will be explained in which a first cell (e.g., a source / reference cell) and a second cell (e.g., a target / candidate cell) are synchronized / asynchronized.

[0300] In addition, the second embodiment will be described by dividing into cases where the above-mentioned predetermined timer (time alignment timer) has expired (options 1 to 4) and cases where it has not expired (options 5 to 9). Note that the timer may be associated with the TA obtained by UE-based TA measurement.

[0301] Options 1 to 4 correspond to option 1 in the first embodiment, and assume a case where the TA is determined to be invalid due to the expiration of the timer.

[0302] Options 5 to 9 correspond to options 2 / 3 in the first embodiment, and assume a case where the TA is determined to be invalid based on a threshold value regardless of whether the timer has expired (while the timer is running).

[0303] In addition, in each of the following options, the candidate cells associated with the TA may be configured / indicated by any signaling (higher layer signaling / physical layer signaling).

[0304] [Option 1] When the timer expires, the UE may request the NW to stop the timer. The request for stopping may be implemented using UCI / MAC CE. That is, the timer may be maintained on the NW side unless the UE requests the timer to be stopped.

[0305] [Option 2] If the timer expires, the UE does not have to do anything, i.e., the timer may be maintained even if it expires. This option means that the UE waits for instructions from the network.

[0306] [Option 3] If the timer expires, the UE may reacquire the TA through UE-based TA measurements.

[0307] [Option 4] If the timer expires, the UE may request the NW to trigger TA acquisition / measurement. TA acquisition / measurement may be performed using a RACH indicated / triggered by a PDCCH (e.g., a PDCCH ordered RACH) or UE-based TA measurement. The request may be performed using UCI / MAC CE.

[0308] [Option 5] Even if the timer has not expired, if it is determined that the TA is invalid while the timer is running as in the first embodiment described above, the UE may request the NW to stop the timer. The request to stop may be implemented using UCI / MAC CE. That is, the timer may be maintained on the NW side unless the UE requests the timer to be stopped.

[0309] [Option 6] Even if the timer has not expired, if the TA is determined to be invalid while the timer is running as in the first embodiment described above, the UE may determine (or consider) that the timer has expired. In other words, the timing at which the TA is determined to be invalid may be the timing at which the timer expires.

[0310] [Option 7] Even if the timer has not expired, if the TA is determined to be invalid while the timer is running as in the first embodiment described above, the UE may not take any action. That is, the timer may be maintained even if it has expired. This option means that the UE waits for an instruction from the network.

[0311] [Option 8] Even if the timer has not expired, if the TA is determined to be invalid while the timer is running as in the first embodiment described above, the UE may reacquire the TA by UE-based TA measurement.

[0312] [Option 9] Even if the timer has not expired, if the TA is determined to be invalid during the timer startup as in the first embodiment described above, the UE may request the NW to trigger acquisition / measurement of the TA. The TA acquisition / measurement may be performed using a RACH indicated / triggered by a PDCCH (e.g., a PDCCH ordered RACH) or UE-based TA measurement. The request may be made using UCI / MAC CE.

[0313] According to the second embodiment described above, the UE can appropriately control the timer when it is determined that the TA is invalid.

[0314] <Third Embodiment> The third embodiment will describe a case where the network determines the validity of TA in relation to the above-mentioned Analysis 4. More specifically, the third embodiment will describe the UE operation when the network determines the validity of TA.

[0315] The following describes the conditions under which the UE determines that the TA is valid (embodiment 3-1), the conditions under which the UE determines that the TA is invalid (embodiment 3-2), and the specific operation of the UE based on the validity of the TA (embodiment 3-3). Each embodiment can be applied in appropriate combination.

[0316] [Embodiment 3-1] The UE may determine that the TA is valid if at least one of the conditions of the following options 1 to 6 is satisfied.

[0317] Option 1: When the UE does not receive a specific signal during a certain duration. The certain duration may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification. The specific signal may be any signal / channel that triggers TA acquisition / measurement for the same candidate cell.

[0318] <<Option 2>> When the UE receives a cell switch command MAC CE (CSC MAC CE).

[0319] <<Option 3>> When the UE receives a TAC MAC CE.

[0320] <<Option 4>> When the UE does not receive a TAC MAC CE within a certain period of time, which may be configured / indicated by higher layer signaling / physical layer signaling, or may be predefined by a specification.

[0321] Option 5: When the UE receives a specific signal, which may be any signal / channel that triggers TA acquisition / measurement for different candidate cells.

[0322] Option 6: The UE may unconditionally expect the TA to always be valid.

[0323] [Embodiment 3-2] The UE may determine that the TA is invalid if at least one of the conditions in options 7 to 10 below is met.

[0324] Option 7: The UE receives a specific signal during a certain duration. The certain duration may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification. The specific signal may be any signal / channel that triggers TA acquisition / measurement for the same candidate cell.

[0325] Option 8: The UE receives a TAC MAC CE within a certain time period. The certain time period may be configured / indicated by higher layer signaling / physical layer signaling, or may be predefined by a specification.

[0326] <Option 9> - If the UE does not receive the TAC MAC CE.

[0327] Option 10: When the UE does not receive a specific signal, the specific signal may be any signal / channel that triggers TA acquisition / measurement for different candidate cells.

[0328] [Embodiment 3-3] The UE may apply at least one of the operations of Options A to E when the following condition (whether the TA is valid or not) is satisfied. That is, the UE may apply the operations of Options A to E based on the validity of the TA. Specifically, Options A to B correspond to the case where the TA is valid, and Options C to E correspond to the case where the TA is invalid.

[0329] Option A: If the TA is valid, the UE may start a timer associated with the TA.

[0330] <Option B> If the TA is valid, the UE may keep the corresponding TA.

[0331] Option C: If the TA is invalid, the UE may stop the timer associated with the TA.

[0332] <Option D> If a TA is invalid, the UE may delete the corresponding TA.

[0333] <<Option E>> If TA is disabled, the UE may perform UE-based TA measurements.

[0334] According to the third embodiment described above, the UE operation can be appropriately controlled based on the validity of the TA determined by the network.

[0335] Fourth Embodiment The fourth embodiment relates to the above-mentioned analyses 5 and 6, and describes a case where the network triggers the acquisition / measurement of TA.

[0336] [Embodiment 4-1] In embodiment 4-1, when TA is valid (the timer has not expired), the following cases are divided into cases 1 to 3, and the UE operation corresponding to each case will be described.

[0337] <<Case 1>> In Case 1, it is assumed that an indication of a candidate cell on which UE-based TA measurement is performed is included in any signal / channel (e.g., TAC MAC CE, PDCCH order, etc.) that triggers UE-based TA measurement. In Case 1, the UE operation in this case is explained by classifying it into the following options 1 to 4.

[0338] <Option 1> The UE may not expect any particular behavior, because if the TA of the indicated candidate cell is determined to be valid by the UE, the UE-based TA measurement will be triggered. Note that whether the UE performs UE-based TA measurement if the TA is still valid may depend on the UE implementation.

[0339] <Option 2> The UE may perform UE-based TA measurements for the indicated candidate cells, for example, if the timer associated with the indicated candidate cell is shorter than a certain value / threshold. The certain value / threshold may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification.

[0340] Option 3: The UE may not perform UE-based TA measurements for the indicated candidate cells, for example, if the timer associated with the indicated candidate cell is longer than a certain value / threshold. The certain value / threshold may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification.

[0341] <Option 4> The UE may determine (consider) that the timer associated with the indicated candidate cell has expired.

[0342] <<Case 2>> In Case 2, it is assumed that any signal / channel (e.g., TAC MAC CE, PDCCH order, etc.) that triggers the UE-based TA measurement does not include an indication of the candidate cell on which the UE-based TA measurement is performed. In Case 2, the UE operation in this case is explained by classifying it into the following options 5 to 9.

[0343] <Option 5> The UE may not expect any specific behavior, because the UE-based TA measurement is triggered if the TA of the candidate cell configured for UE-based TA measurement is determined to be valid by the UE. Note that whether the UE performs UE-based TA measurement when the TA is still valid may depend on the UE implementation.

[0344] <Option 6> The UE may perform UE-based TA measurements for all candidate cells configured for UE-based TA measurements, for example, if a timer associated with any of the candidate cells is shorter than a certain value / threshold. The certain value / threshold may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification.

[0345] <Option 7> The UE may perform UE-based TA measurements for some candidate cells, excluding those for which the UE determines that TA is valid. For example, this may be the case when a timer associated with any of the candidate cells is longer than a certain value / threshold. The certain value / threshold may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification.

[0346] <Option 8> The UE may not perform UE-based TA measurements for all candidate cells configured for UE-based TA measurements, for example, if a timer associated with any of the candidate cells is longer than a certain value / threshold. The certain value / threshold may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification.

[0347] <Option 9> The UE may determine (consider) that the timer for the candidate cell configured for UE-based TA measurements has expired.

[0348] <<Case 3>> In Case 3, it is assumed that the UE receives a PDCCH order. In Case 3, the UE operation in this case will be explained by classifying it into the following options 10 to 12.

[0349] <Option 10> The UE may not perform a PDCCH order RACH, i.e., the UE may not be indicated / triggered to perform a RACH by the PDCCH. For example, this may be the case when a timer associated with the indicated candidate cell is longer than a certain value / threshold. The certain value / threshold may be configured / indicated by higher layer signaling / physical layer signaling or may be predefined by a specification.

[0350] <Option 11> The UE may perform a PDCCH order RACH, i.e., the UE may be indicated / triggered by the PDCCH, for example, when a timer associated with the indicated candidate cell is shorter than a certain value / threshold. The certain value / threshold may be configured / indicated by higher layer / physical layer signaling or may be predefined by a specification.

[0351] <Option 12> The UE may not expect any particular behavior, since a PDCCH order RACH is triggered if the TA of a candidate cell configured for UE-based TA measurements is determined to be valid by the UE. Note that whether the UE performs a PDCCH order RACH if the TA is still valid may depend on the UE implementation.

[0352] <<Note>> Note that acquisition / measurement of each TA may be performed if the TA is invalid (timer expired).

[0353] [Embodiment 4-2] In embodiment 4-2, when UE-based TA measurement is ongoing, the following cases 1 to 3 will be described, and UE operations corresponding to each case will be explained.

[0354] <<Case 1>> In Case 1, it is assumed that an indication of a candidate cell on which UE-based TA measurement is to be performed is included in any signal / channel (e.g., TAC MAC CE, PDCCH order, etc.) that triggers UE-based TA measurement. In Case 1, the UE operation in this case is explained by classifying it into the following options 1 to 3.

[0355] <Option 1> The UE does not need to expect any specific behavior, because if the TA of the indicated candidate cell is determined to be valid by the UE, a UE-based TA measurement will be triggered. Note that whether the UE performs a (new) UE-based TA measurement when a UE-based TA measurement is in progress may depend on the UE implementation.

[0356] <Option 2> The UE may perform UE-based TA measurements for the indicated candidate cells. That is, a newly triggered UE-based TA measurement may always take priority. <Option 3> The UE may not perform UE-based TA measurements for the indicated candidate cells. That is, a previously triggered UE-based TA measurement may always take priority.

[0357] <<Case 2>> In Case 2, it is assumed that any signal / channel (e.g., TAC MAC CE, PDCCH order, etc.) that triggers the UE-based TA measurement does not include an indication of the candidate cell on which the UE-based TA measurement is performed. In Case 2, the UE operation in this case is explained by classifying it into the following options 4 to 7.

[0358] <Option 4> The UE does not need to expect any specific behavior, because the UE-based TA measurement is triggered when the TA of the candidate cell configured for UE-based TA measurement is determined to be valid by the UE. Note that whether the UE performs a (new) UE-based TA measurement when a UE-based TA measurement is in progress may depend on the UE implementation.

[0359] <Option 5> The UE may perform UE-based TA measurements for all candidate cells configured for UE-based TA measurements, i.e., a newly triggered UE-based TA measurement may always be prioritized.

[0360] <Option 6> The UE may perform UE-based TA measurements on some candidate cells excluding the candidate cell for which UE-based TA measurements are in progress.

[0361] <Option 7> The UE may not perform UE-based TA measurements for all candidate cells configured for UE-based TA measurements, i.e., a previously triggered UE-based TA measurement may always take precedence.

[0362] <<Case 3>> In Case 3, it is assumed that the UE receives a PDCCH order. In Case 3, the UE operation in this case will be explained by classifying it into the following options 8 to 10.

[0363] <Option 8> The UE may not perform a PDCCH order RACH, i.e., the UE may not be indicated / triggered by the PDCCH to perform RACH. In this case, UE-based TA measurements may always take priority.

[0364] <Option 9> The UE may perform a PDCCH order RACH, i.e., the UE may be indicated / triggered by the PDCCH for RACH, in which case the PDCCH order RACH may always take priority.

[0365] <Option 10> The UE may not expect any specific behavior, since a PDCCH order RACH is triggered if the TA of a candidate cell configured for UE-based TA measurement is determined to be valid by the UE. Note that whether the UE performs a PDCCH order RACH when UE-based TA measurement is in progress may depend on the UE implementation.

[0366] <<Note>> Note that if UE-based TA measurement is not in progress, acquisition / measurement of each TA may be performed.

[0367] According to the fourth embodiment described above, it is possible to control the UE operation in cases where the network triggers the acquisition / measurement of TA.

[0368] Fifth Embodiment In a fifth embodiment, a TA instruction in UE-based TA measurement will be described in relation to the above-described Analysis 7.

[0369] When different configurations are applied to the TA acquisition / measurement method, the UE may expect different TA indication methods in the cell switch command. The different TA indication methods may be predefined. Specific examples are described below in Options 1 to 4.

[0370] [Option 1] In the cell switch command MAC CE, an absolute TA value including TA=0 may be indicated. In this case, the UE may assume that the TA of the indicated candidate cell is the indicated absolute TA value.

[0371] [Option 2] In the cell switch command MAC CE, the TAG ID / Cell ID corresponding to the TA to be applied may be indicated, in which case the UE may assume that the TA of the indicated candidate cell is the TA value corresponding to the indicated TAG ID / Cell ID.

[0372] [Option 3] The UE may be instructed in the cell switch command MAC CE to directly apply the TA obtained by the UE-based TA measurement. In this case, the UE may perform UE-based TA measurement to obtain the TA of the indicated candidate cell.

[0373] [Option 4] In the case where UE-based TA measurement is configured, at least one of the above options 1 to 3 may be predefined, i.e., the TA may not be explicitly indicated by the cell switch command MAC CE.

[0374] According to the fifth embodiment described above, the TA instruction can be appropriately controlled.

[0375] Sixth Embodiment The sixth embodiment describes the UE behavior in the case where TA is indicated by the cell switch command MAC CE, in relation to the above analysis 8. The UE may apply at least one of the following options 1 to 3:

[0376] [Option 1] The UE may apply the absolute TA value indicated in the cell switch command MAC CE.

[0377] [Option 2] The UE may apply the TA it has obtained / measured.

[0378] [Option 3] The UE may apply the TA associated with the longer timer among the indicated multiple TAs. For example, if multiple TA acquisition methods are configured for a candidate cell, a timer associated with each TA acquisition method may be configured. More specifically, this includes RAR and PDCCH order RACH without UE-based TA measurement.

[0379] According to the sixth embodiment described above, in a case where TA is instructed by a cell switch command MAC CE, it is possible to appropriately control the UE operation.

[0380] <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.

[0381] 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.

[0382] 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.

[0383] Furthermore, notification of any information to the UE in the above embodiments may be performed periodically, semi-persistently, or aperiodically.

[0384] [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.

[0385] 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.

[0386] If the notification is made by UCI, the notification may be transmitted using PUCCH or PUSCH.

[0387] Furthermore, any information in the above-described embodiments may be notified from the UE periodically, semi-persistently, or aperiodically.

[0388] [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.

[0389] 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.

[0390] The specific UE capabilities 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 each option (or each alternative) of the above embodiments or a combination of options.

[0391] 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).

[0392] 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)).

[0393] 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.

[0394] If the UE does not support at least one of the specific UE capabilities or is not configured with the specific information, the UE may apply, for example, the behavior of Rel. 15 / 16 / 17.

[0395] (Supplementary Notes) The following inventions are supplementary notes regarding an embodiment (first to third embodiments) of the present disclosure. [Supplementary Note 1] A terminal comprising: a controller that performs UE-based timing advance measurement for a candidate cell; and a receiver that receives a setting related to a timer or a threshold for determining the validity of a timing advance obtained by the UE-based timing advance measurement, wherein the controller determines the validity of the timing advance based on the setting. [Supplementary Note 2] The terminal according to Supplementary Note 1, wherein the controller determines the validity of the timing advance after a certain time has elapsed since measuring the timing advance. [Supplementary Note 3] The terminal according to Supplementary Note 1 or Supplementary Note 2, wherein the controller determines the validity of the timing advance when the timer expires or when the measured value of the timing advance is outside the range of the threshold. [Supplementary Note 4] The terminal according to any of Supplements 1 to 3, wherein the controller determines the validity of the timing advance depending on whether a specific signal has been received within a certain time.

[0396] (Supplementary Notes) The following inventions are supplementary notes regarding an embodiment (fourth to sixth embodiments) of the present disclosure. [Supplementary Note 1] A terminal comprising: a receiver unit that receives a signal that triggers a UE-based timing advance measurement; and a controller that performs a UE-based timing advance measurement for a candidate cell based on the signal, wherein the controller controls the execution of the UE-based timing advance measurement based on whether or not the signal includes an indication of a candidate cell for which the UE-based timing advance measurement is to be performed, or based on reception of a physical downlink control channel order. [Supplementary Note 2] The terminal according to Supplementary Note 1, wherein the controller determines the validity of the timing advance, and if the controller determines that the timing advance is valid, determines to perform the UE-based timing advance measurement based on a timer associated with the candidate cell. [Supplementary Note 3] The terminal according to Supplementary Note 1 or Supplementary Note 2, wherein the controller determines which UE-based timing advance measurement to trigger based on whether or not a UE-based timing advance measurement is in progress. [Supplementary Note 4] The terminal according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the receiving unit receives a cell switching command, and the control unit controls the timing advance based on information regarding a timing advance included in the cell switching command.

[0397] (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.

[0398] 19 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).

[0399] 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.

[0400] 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.

[0401] 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))).

[0402] 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.

[0403] 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).

[0404] 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.

[0405] 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.

[0406] 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.

[0407] 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.

[0408] 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.

[0409] The user terminal 20 may be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0410] 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).

[0411] 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.

[0412] 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.

[0413] 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.

[0414] 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).

[0415] 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.

[0416] 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.

[0417] 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.

[0418] 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.

[0419] 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.

[0420] 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.

[0421] 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.

[0422] 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.

[0423] 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).

[0424] (Base Station) Fig. 20 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.

[0425] 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.

[0426] 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.

[0427] 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.

[0428] 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.

[0429] 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.

[0430] 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.

[0431] 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.

[0432] 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.

[0433] 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.

[0434] 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.

[0435] 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.

[0436] 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.

[0437] 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.

[0438] 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.

[0439] 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.

[0440] The transmitting section and receiving section of the base station 10 in the present disclosure may be configured by at least one of the transmitting / receiving section 120, the transmitting / receiving antenna 130, and the transmission path interface 140.

[0441] The transceiver 120 may transmit a setting related to a timer or a threshold for determining the validity of the timing advance obtained by the UE-based timing advance measurement for the candidate cell. The transceiver 120 may transmit a signal or a physical downlink control channel order for triggering the UE-based timing advance measurement for the candidate cell. The transceiver 120 may receive the obtained UE-based timing advance measurement from the terminal based on the signal.

[0442] The control unit 110 may determine the validity of the timing advance based on information about the timing advance transmitted from the terminal.

[0443] (User Terminal) Fig. 21 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.

[0444] 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.

[0445] 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.

[0446] 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.

[0447] 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.

[0448] 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.

[0449] 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.

[0450] 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.

[0451] 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.

[0452] 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.

[0453] 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.

[0454] 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.

[0455] 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.

[0456] 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.

[0457] 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.

[0458] 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.

[0459] The measurement unit 223 may derive channel measurements for CSI calculation based on 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 interference measurement resources. The interference measurement resources may be at least one of NZP CSI-RS resources for interference measurement, CSI-Interference Measurement (IM) resources, 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.

[0460] 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.

[0461] The transceiver 220 may receive a setting for a timer or a threshold for determining the validity of the timing advance obtained by the UE-based timing advance measurement. The transceiver 220 may receive a signal for triggering the UE-based timing advance measurement. The transceiver 220 may receive a cell switch command.

[0462] The control unit 210 may perform UE-based timing advance measurement for a candidate cell. The control unit 210 may determine the validity of the timing advance based on the setting. The control unit 210 may determine the validity of the timing advance after a certain time has elapsed since measuring the timing advance. The control unit 210 may determine the timing advance as invalid if the timer expires or if the measured timing advance value is outside the threshold range. The control unit 210 may determine the validity of the timing advance based on whether or not a specific signal is received within a certain time period. The control unit 210 may perform UE-based timing advance measurement for a candidate cell based on the signal. The control unit 210 may control the execution of the UE-based timing advance measurement based on whether or not the signal includes an indication of the candidate cell for which UE-based timing advance measurement is to be performed, or based on the reception of a physical downlink control channel order. The control unit 210 may determine the validity of the timing advance, and if it determines that the timing advance is valid, may determine to perform the UE-based timing advance measurement based on a timer associated with the candidate cell. The control unit 210 may determine which UE-based timing advance measurement to trigger based on whether there is an ongoing UE-based timing advance measurement. The control unit 210 may control the timing advance based on information about the timing advance included in the cell switch command.

[0463] (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.

[0464] 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.

[0465] 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. 22 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.

[0466] 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.

[0467] 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.

[0468] 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.

[0469] 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.

[0470] 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.

[0471] 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.

[0472] 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.

[0473] 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.

[0474] 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).

[0475] 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.

[0476] 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.

[0477] (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.

[0478] 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.

[0479] 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.

[0480] 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.

[0481] 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.

[0482] 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.

[0483] 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.

[0484] 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.

[0485] 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.

[0486] 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.

[0487] 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.

[0488] 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.

[0489] 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.

[0490] 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.

[0491] 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.

[0492] 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.

[0493] 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.

[0494] 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.

[0495] 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."

[0496] 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.

[0497] 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.

[0498] 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.

[0499] 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.

[0500] 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.

[0501] 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.

[0502] 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.

[0503] 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).

[0504] 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).

[0505] 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).

[0506] 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.

[0507] 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.

[0508] 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).

[0509] 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.

[0510] 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.

[0511] 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.

[0512] 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.

[0513] 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.

[0514] 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.

[0515] 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.

[0516] 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.

[0517] 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.

[0518] 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.

[0519] 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.

[0520] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0521] 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.

[0522] 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.

[0523] 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.

[0524] 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.

[0525] 23 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.

[0526] 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.

[0527] 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).

[0528] 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.

[0529] 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.

[0530] 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.

[0531] 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.

[0532] 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.

[0533] 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).

[0534] 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.

[0535] 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)).

[0536] 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.

[0537] 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.

[0538] 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.

[0539] 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.

[0540] 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.

[0541] 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).

[0542] 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."

[0543] 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.

[0544] 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.

[0545] 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.

[0546] 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.

[0547] 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...."

[0548] 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).

[0549] 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.

[0550] 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."

[0551] 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.

[0552] 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."

[0553] 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.

[0554] 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.

[0555] 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").

[0556] In this disclosure, the terms "of," "for," "regarding," "related to," "associated with," etc. may be read interchangeably.

[0557] 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.

[0558] 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.

[0559] 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 instructing the setting of terminal-based timing advance (TA) measurement for candidate cells, The system includes a control unit that performs terminal-based TA measurement based on the aforementioned upper-layer parameters, The control unit, when measuring the terminal (TA) using the terminal-based TA measurement, receives a physical downlink control channel (PDCCH) order, and executes a random access procedure based on the PDCCH order.

2. The terminal according to claim 1, wherein the control unit determines that the TA is valid based on predetermined signaling.

3. The terminal according to claim 1, further comprising a transmitting unit that reports the ability to support the aforementioned terminal-based TA measurement.

4. The steps include receiving higher-layer parameters that instruct the setting of terminal-based timing advance (TA) measurement for candidate cells, The steps include performing the terminal-based TA measurement based on the aforementioned upper-layer parameters, A wireless communication method for a terminal, comprising the step of performing a random access procedure based on the PDCCH order when measuring the terminal using the terminal-based TA measurement and receiving a physical downlink control channel (PDCCH) order.

5. A transmission unit that sends higher-layer parameters to the terminal instructing the setting of terminal-based timing advance (TA) measurement for candidate cells, The system includes a control unit that instructs the terminal to measure TA using the terminal-based TA measurement based on the upper layer parameters, The control unit, when the TA is measured, instructs the base station to perform a random access procedure by transmitting a physical downlink control channel (PDCCH) order to the terminal.

6. A system having a terminal and a base station, The terminal includes a receiving unit that receives upper-layer parameters instructing the setting of terminal-based timing advance (TA) measurement for candidate cells, The system includes a control unit that performs terminal-based TA measurement based on the aforementioned upper-layer parameters, When the control unit measures the TA using the terminal-based TA measurement and receives a physical downlink control channel (PDCCH) order, it executes a random access procedure based on the PDCCH order. The base station includes a transmitting unit that transmits the upper layer parameters, The system includes a control unit that instructs the terminal to measure the TA based on the aforementioned upper layer parameters, The control unit, when the TA is measured, instructs the terminal to execute the random access procedure by transmitting the PDCCH order.