Terminal, wireless communication method, and base station

Abstract

A terminal according to one aspect of the present disclosure comprises: a reception unit that receives a first downlink signal on a first frequency of a first cell and a second downlink signal on a second frequency of a second cell; and a control unit that, on the basis of the first downlink signal and the second downlink signal, controls a handover from the first cell to the second cell, and controls transmission and reception of data on a third frequency of the second cell.

Description

Terminal, wireless communication method, and base station

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

[0002] In a Universal Mobile Telecommunications System (UMTS) network, Long Term Evolution (LTE) was specified for the purpose of achieving further high data rates, low latency, etc. (Non-Patent Document 1). Also, for the purpose of further increasing capacity and sophistication of LTE (Third Generation Partnership Project (3GPP (registered trademark)) Release (Rel.) 8, 9), LTE-Advanced (3GPP Rel. 10-14) was specified.

[0003] Successor systems to LTE (for example, also referred to as 5th generation mobile communication system (5G), 5G+ (plus), 6th generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 and 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 (for example, Rel. 21 and later, 6G systems), in order to solve social issues in the 2030s and later, the realization of advanced services beyond the 5G NR system is expected.

[0006] However, while it is necessary to consider the regulations for carriers required to realize such services, this consideration has not been sufficient. If this consideration is insufficient, there is a risk that advanced services beyond 5G NR will not be realized.

[0007] Therefore, one of the objectives of this disclosure is to provide a terminal, a wireless communication method, and a base station that can realize advanced services beyond 5G NR.

[0008] A terminal according to one aspect of the present disclosure includes a receiving unit that receives a first downlink signal on a first frequency of a first cell and a second downlink signal on a second frequency of a second cell, and a control unit that controls a handover from the first cell to the second cell and controls the transmission and reception of data on a third frequency of the second cell based on the first downlink signal and the second downlink signal.

[0009] According to one aspect of this disclosure, it is possible to realize advanced services that go beyond 5G NR.

[0010] Figures 1A and 1B show an overview of MIMO. Figure 2A shows an overview of the cellular system. Figure 2B shows an overview of the cell-free system. Figure 3A shows an example overview of hypothetical configuration 1 of the cell-free system. Figure 3B shows an example overview of hypothetical configuration 2 of the cell-free system. Figure 3C shows another example overview of hypothetical configuration 2 of the cell-free system. Figure 4 shows an example of carrier design in this disclosure. Figures 5A and 5B show examples of first and second signals. Figure 6 shows an example of the handover procedure in Embodiment B1-1 when using a perch carrier, anchor carrier and data carrier. Figure 7 shows example of the handover procedure 1 in Embodiment B1-2 when using an anchor carrier and data carrier. Figure 8 shows example of the handover procedure 2 in Embodiment B1-2 when using an anchor carrier and data carrier. Figure 9 shows an example of the operation of the switching target cell in the example of procedure A in Embodiment B1-3. Figure 10 shows an example of the operation of the switching target cell in the example of procedure B-1 in Embodiment B1-3. Figure 11 shows an example of the operation of the switching target cell in the procedure example of procedure B-2 of Embodiment B1-3. Figure 12 shows an example of the operation of the switching target cell in the procedure example of Embodiment B4-1. Figure 13 shows an example of the operation of the switching target cell in the procedure example of Embodiment B4-2. Figure 14 shows an example of the relationship between DL-RS and PRACH when M=1 when PRACH is transmitted on the anchor carrier. Figure 15 shows an example of the relationship between DL-RS and PRACH when M>1 when PRACH is transmitted on the anchor carrier. Figure 16 shows an example of the relationship between DL-RS and PRACH when M=1 when PRACH is transmitted on the perch carrier. Figure 17 shows an example of the relationship between DL-RS and PRACH when M>1 when PRACH is transmitted on the perch carrier. Figure 18 is a diagram showing an example of the schematic configuration of a wireless communication system according to one embodiment. Figure 19 is a diagram showing an example of the configuration of a base station according to one embodiment. Figure 20 shows an example of the configuration of a user terminal according to one embodiment. Figure 21 shows an example of the hardware configuration of a base station and a user terminal according to one embodiment.Figure 22 shows an example of a vehicle according to one embodiment.

[0011] (Cell-free) Existing wireless communication systems (e.g., 5G NR) employ a cellular system in which, in principle, one antenna / transmit / receive point (TRP) forms one cell. The area formed by such a cell is a fixed / static area.

[0012] Furthermore, existing wireless communication systems (e.g., Rel. 16 and later) have introduced Distributed Multi Input Multi Output (Distributed MIMO, e.g., multi-TRP using multiple TRPs) which forms a communication area by the coverage of multiple antennas / TRPs. Distributed MIMO allows for simultaneous communication using multiple antennas / TRPs, as well as communication using a single antenna / TRP.

[0013] By adopting distributed MIMO, a more favorable line-of-sight environment can be established, and MIMO performance can be improved.

[0014] Figures 1A and 1B are diagrams illustrating the overview of MIMO. Figure 1A shows an example of Co-located MIMO. In Co-located MIMO, one UE communicates with one antenna / TRP.

[0015] On the other hand, Figure 1B shows an example of distributed MIMO. In distributed MIMO, one UE communicates with multiple coordinated antennas / TRPs.

[0016] In future wireless communication systems (e.g., Rel. 20 and beyond), the introduction of self-free communication is being considered with the aim of further improving performance and energy efficiency through reducing interference between multiple antennas / TRPs, creating a line-of-sight environment that supports the use of high frequencies, improving the overall frequency utilization efficiency of the system, and applying equal and high-quality communication to each user.

[0017] Selfly may also be called selfly massive MIMO (mMIMO) or large-scale distributed MIMO (D-MIMO). Selfly uses coherent coordination of a large number of access points. Selfly may include at least one of the following: ultra-dense deployment, scalable cooperation, user-centric clustering, supercarrier aggregation, or analog fronthaul. The user plane for selfly may provide more flexible scheduling than existing scheduling. The control plane for selfly may retain several forms of cells to facilitate signaling.

[0018] In cell-free systems, unlike conventional cellular systems, a single area (which may also be called a cell or subcell) may be formed by multiple antennas / TRPs. In other words, this area may mean a cell that is independent of the position of the antennas / TRPs.

[0019] In self-free systems, the set of antennas / TRPs used for area formation may be changed according to the needs of the user audience (UE). For example, the set of antennas / TRPs may be changed based on factors other than antenna / TRP coverage, such as the number of UEs, traffic volume, or communication purpose (e.g., initial access, data communication, measurement, reporting, etc.).

[0020] In other words, in a self-free setup, coverage between multiple antennas / TRPs may overlap.

[0021] In a cell-free configuration, the direction in which each antenna / TRP transmits a synchronization signal (which may be called, for example, a synchronization signal block (SSB), a synchronization signal / physical broadcast channel (SS / PBCH) block, etc.) may be controlled.

[0022] Furthermore, in a self-free system, the central unit (CU) and distributed unit (DU) may be virtualized for each antenna. Alternatively, each antenna may be managed by the CU alone.

[0023] Figure 2A is a diagram illustrating the overview of the cellular system. Figure 2A shows the cells formed by each antenna / TRP, and the UE communicates based on these cells.

[0024] On the other hand, Figure 2B is a diagram illustrating the overview of a cell-free system. In the example shown in Figure 2B, the installed antennas / TRPs do not form fixed / static cells in the cellular system. As shown in Figure 2B, in a cell-free system, one or more antennas / TRPs form areas depending on the conditions. Therefore, in a cell-free system, each antenna / TRP does not have to correspond to the same physical cell ID, and areas between multiple antennas / TRPs may overlap.

[0025] Self-reliance may be achieved, for example, by adjusting a set of antennas / TRPs controlled by a central control unit (e.g., a CU).

[0026] In a cell-free system, a first cell (which may be called, for example, a cell / supercell / macrocell / large cell) with a fixed physical range, similar to a cell in a 5G NR system, and a second cell (which may be called, for example, a subcell / area / microcell / cell / small cell / second cell within the first cell) whose physical range changes quasi-statically / dynamically based on conditions, may be formed.

[0027] For example, the first cell may be called a supercell to distinguish it from a second cell. If a supercell consists of multiple second cells, the second cells may have the same definition / operation / coverage as existing cells in the NR. For example, the second cells may be called subcells to distinguish them from the first cell. If a supercell or cell consists of multiple subcells, the subcells may have the same definition / operation / coverage as existing cells in the NR.

[0028] The first cell may be a cell newly defined in a future wireless communication system, or a cell definition from an existing wireless communication system may be reused.

[0029] The configurations of the first and second cells can be assumed to be as follows: Assumption 1: The first cell is composed of multiple TRPs, each having a single cell ID (physical cell ID (PCI)). Multiple TRPs can cooperate in sending and receiving data. Assumption 2: The first cell is composed of multiple TRPs (or subcells) with different cell IDs. Multiple TRPs / subcells can cooperate in sending and receiving data.

[0030] Figure 3A shows an example of the overview of hypothetical configuration 1 for cell-free operation. In the example shown in Figure 3A, each TRP included in the first cell (supercell / cell) has the same PCI (PCI #0). Multiple TRPs can communicate in cooperation with a single UE.

[0031] Figure 3B shows an example of an overview of hypothetical configuration 2 for cell-free operation. In the example shown in Figure 3B, each TRP included in the first cell (supercell / cell) has a different PCI (PCI #0 to #9). Multiple TRPs can communicate in cooperation with a single UE.

[0032] Figure 3C shows another example of the overview of assumption 2 of the cell-free configuration. In the example shown in Figure 3C, a PCI is assigned to each TRP contained in the first cell (supercell / cell). In the example shown in Figure 3C, unlike the example in Figure 3B, the same one PCI may correspond to multiple TRPs. Multiple TRPs can communicate in cooperation with a single UE.

[0033] Transmitting / receiving with TRP / subcell coordination may be based on at least one of the following methods supported in NR: - Single TRP / subcell transmission with dynamic TRP / subcell switching (single TRP transmission). - Joint transmission using multiple TRP / subcells (multi-TRP joint transmission). The joint transmission may be based on single DCI or multi-DCI. The joint transmission may be non-coherent joint transmission (NCJT) or coherent joint transmission (CJT).

[0034] Assuming an ideal backhaul and close coordination for self-free operation, CJT may be preferred over NCJT in a joint transmission scheme, and single DCI-based joint transmission may be preferred over multi-DCI-based joint transmission.

[0035] Selfly can enable large-scale distributed MIMO, low-layer (e.g., L2 / L1) mobility, and flexible TRP clustering. For example, when applied to ultra-high-density TRP, cell / TRP clustering for mobility / control and data can be separated.

[0036] Cell-free design offers several advantages, including: • Increased TRP density per cell. This improves the Signal-Noise Ratio (SNR) across all UEs, including conventional cell edge areas. • Flexible (e.g., UE-centric) TRP clustering for cell construction. This reduces the number of UEs affected by inter-cell / inter-TRP interference. • Enhanced mobility at lower layers. A single clustering can accommodate more TRPs, enabling seamless movement through, for example, L1-level operations.

[0037] With regard to self-free design, either Concept 1 or 2 below may be applied.

[0038] <Concept 1> Selfly targets the selection of multiple TRPs / access points (APs), and transmission / reception with TRPs / APs is limited to data only (e.g., PDSCH / PUSCH) (e.g., at the physical / MAC layer). In this case, there is no significant impact on cell selection, initial access, or mobility compared to existing methods. LTM (L1 / L2-triggered mobility, e.g., LTM prior to Rel. 18) may be reusable, or LTM functionality may be enhanced. L1 measurement / reporting or enhanced SRS transmission may be performed for the selection of multiple TRPs / APs, CSI measurement / reporting or enhanced SRS transmission for CSI of TRPs / APs with different clusterings, etc.

[0039] <Concept 2> The selection of multiple TRP / APs and transmission / reception with TRP / APs applies to both control channels / signals (e.g., in RRC) and data (e.g., PDSCH / PUSCH) (e.g., in the physical / MAC layer).

[0040] In this case, compared to existing methods, there are impacts on cell selection, initial access, and mobility, in addition to the measurement / reporting of L1 / CSI for data in Concept 1. For example, since the UE needs to access multiple TRP / APs during initial access, the SSB / SI / RACH also needs to be redesigned.

[0041] When clustering multiple TRP / APs for control channels / signals and data, the clustering method (e.g., TRP / APs within the cluster) may be the same or different. In this case, potential impacts may arise when clustering is performed on multiple DU / CUs located in geographically different locations.

[0042] <CC (Carrier Aggregation (CA) Scenarios) of Different Frequencies> Selfly may be applied to CC (CA scenarios) of different frequencies. The above multiple TRP / AP may be processed individually for each CC or jointly across multiple CCs. For example, clustering and scheduling may take into account both the dimensions of the TRP and the dimensions of the CC.

[0043] (Extension of conditional PSCell change (CPC)) In Rel. 17, either the master node (MN, primary node) in the master cell group (MCG) or the secondary node (SN, secondary node) in the secondary cell group (SCG) can start CPC. Also, in addition to CPC (intra-SN CPC), CPC (inter-SN CPC) is supported.

[0044] In inter-SN CPC, the MN that starts CPC requests the SN to which the candidate cell for change belongs to secure resources for the candidate cell. The SN that receives the request determines whether resource securing is possible, and if it is possible, transmits a list of cells for which resources can be secured to the MN. The MN transmits a CPC setting including the candidate cell list and the execution condition for PSCell change to the candidate cell to the UE. The execution condition may be, for example, that the communication quality of the candidate cell is higher than a certain value or more than the communication quality of the cell to which the UE is connected. The UE performs measurements in response to the reception of the CPC setting, and if any candidate cell satisfies the execution condition, changes the PSCell to that candidate cell. The UE notifies the MN that CPC has been applied and the cell to which CPC has been changed. The MN starts a resource release procedure for the SN to which the original PSCell belongs.

[0045] At the start of dual connectivity (DC), in PSCell addition, conditional PSCell addition (CPA) that adopts conditional execution (such as setting a plurality of candidate cells and execution conditions like CPC) is defined.

[0046] (Conditional handover (CHO) for network energy saving (NES)) In Rel. 18, CHO for NES turns off the cell and moves the UE to another cell. DCI format 2_9 is diverted to indicate the execution of CHO.

[0047] The operation of turning off a cell is regarded as one of the NES operations. In Rel. 16, the CHO for the UE is to determine whether to perform a handover when specific conditions are met. In the NES CHO of Rel. 18, the L1 indication is one of the conditions for executing the CHO to drive the UE out of the cell that is planned to be turned off. The NES CHO indication in DCI format 2_9 is set only for the PCell. The bit position of the indication is determined by using one (common) start position of the discontinuous transmission (DTX) / discontinuous reception (DRX) of the cell and the L1 indication of the DTX / DRX of the cell (the bit length of the DTX / DRX of the cell for the PCell).

[0048] (L1 / L2 inter-cell mobility) The UE may perform UL transmission for one or more cells / TRPs. As procedures in this case, the following Scenario 1 or Scenario 2 can be considered. In the present disclosure, the serving cell may be read as a TRP in the serving cell. Layer1 / layer2 (L1 / L2), DCI / Medium Access Control Control Element (MAC CE) may be read as each other. In the present disclosure, a Physical Cell Identity (PCI) different from the current serving cell's PCI may simply be described as "different PCI". Non-serving cells, cells with different PCIs, and additional cells may be read as each other.

[0049] <Scenario 1> Scenario 1 corresponds to, for example, inter-cell mobility of multi-TRP, but may also be a scenario that does not correspond to inter-cell mobility of multi-TRP.

[0050] (1) The UE receives from the serving cell the SSB settings for beam measurement of the TRP corresponding to a PCI different from that of the serving cell, and the settings necessary to use wireless resources for data transmission and reception, including the resources of the different PCI. (2) The UE performs beam measurement of the TRP corresponding to the different PCI and reports the beam measurement results to the serving cell. (3) Based on the above report, the Transmission Configuration Indication (TCI) status 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 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. The UE must use a common channel from the serving cell (Broadcast Control Channel (BCCH), Paging Channel (PCH)), etc., as in conventional systems.

[0051] In Scenario 1, when the UE sends and receives signals with the additional cell / TRP (the TRP corresponding to the PCI of the additional cell), the serving cell (the UE's assumption of the serving cell) remains unchanged. The UE sets higher-layer parameters related to the PCI of the non-serving cell from the serving cell. Scenario 1 may be applied, for example, in Rel. 17.

[0052] This scenario assumes that the UE moves from a PCI#1 cell (serving cell) to a PCI#3 cell (additional cell) (overlapping with the serving cell). Rel. 17 does not support L1 / L2 switching of serving cells.

[0053] An additional cell is a cell with an additional PCI that is different from the PCI of the serving cell. UEs can receive and transmit UE-dedicated channels from additional cells. UEs need to be within the coverage of the serving cell to receive UE common channels (e.g., system information / paging / short messages). If a UE moves outside the coverage of the serving cell, a cell switch is required, such as through a handover (also called L3 mobility).

[0054] <Scenario 2> In Scenario 2, L1 / L2 cell mobility is applied. With L1 / L2 cell mobility, serving cell changes can be made using functions such as beam control without RRC reconfiguration. In other words, transmission and reception with additional cells are possible without handover. Since handover requires RRC reconnection and other factors, resulting in a period of no data communication, applying L1 / L2 cell mobility that does not require handover allows data communication to continue 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.

[0055] (1) The UE receives the SSB configuration of a cell with a different PCI (additional cell) from the serving cell for beam measurement / serving cell change. (2) The UE performs beam measurement on 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 the different PCI (serving cell configuration) by upper layer signaling (e.g., RRC). In other words, a pre-configuration regarding 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 by L1 / L2 signaling in accordance with the serving cell change. The activation of the TCI state and the serving cell change may be performed separately. (5) The UE changes the serving cell (assumed serving cell) and starts receiving / transmitting using the pre-configured UE-specific channel and TCI state.

[0056] In other words, in Scenario 2, the serving cell (the assumed serving cell in the UE) is updated by L1 / L2 signaling. Scenario 2 may also be applied in Rel. 18.

[0057] In Rel. 18, serving cells are switched via L1 / L2 (e.g., DCI / MAC CE). UEs can receive / transmit UE-dedicated / common channels to and from the new serving cell (or target serving cell). UEs may be removed from the coverage of the current serving cell (e.g., Current serving cell).

[0058] <Rel. 18LTM> L3 measurement is used as the criterion for Rel. 15 handover. An RRC reset message is used to notify the UE of the Rel. 15 handover. After the Rel. 15 handover is notified to the UE, RACH establishes DL / UL synchronization with the target (switching destination) cell.

[0059] The motivation for Rel. 18LTM is to reduce downtime. Handover is performed without using at least one of RACH, RRC reset, or MAC reset. Candidate cells are located in the same CU as the serving cell. Candidate cells may be on the same frequency as the serving cell, or on a different frequency.

[0060] In Rel. 18LTM, DL synchronization, L1 measurement reporting, UL synchronization, and TCI status activation can be performed on candidate cells before cell switching.

[0061] The cell switch command (CSC) MAC CE may include the following information for the target cell: a setting ID indicating the target cell, a TCI status ID, a TA value, and optionally, a CFRA resource index.

[0062] Prior to the CSC MAC CE, a RACH can be performed on candidate cells based on a CFRA PDCCH order. The RACH procedure is completed after the PRACH transmission [without RAR reception]. The TA values ​​for candidate cells are maintained by the network only. The TA values ​​for target cells only are indicated by the CSC MAC CE.

[0063] For UL synchronization, a UE-based TA measurement can be configured for each candidate cell. If the candidate cell's ltm-UE-MeasuredTA-ID is equal to the serving cell's ltm-UE-MeasuredTA-ID, the UE performs a UE-based TA measurement for the candidate cell. The TA value is calculated from the Rx timing difference between the serving cell and the candidate cell. The TA value is maintained solely by the UE. The calculation timing depends on the UE implementation. If a TA for the target cell is not specified in the CSC MAC CE, and a UE-based TA measurement is configured for the target cell, the UE performs a UE-based TA measurement and uses the TA derived from that measurement.

[0064] RACH-less LTM and RACH-based LTM can be configured / instructed.

[0065] The conditions for RACH-less LTM are that the TA for the target cell is either specified within the CSC MAC CE or derived by the UE itself. The TA specified within the CSC MAC CE takes precedence over the TA derived by the UE itself. Configured grants (CG) and dynamic grants (DG) can be used for the initial UL transmission to the target cell. The association between the CG occasion and the TCI status ID is established by the RRC. The UE selects the CG occasion associated with the beam (TCI status ID) specified within the CSC MAC CE.

[0066] The conditions for a RACH-based LTM are any other cases than those for a RACH-less LTM. In addition to CBRA and CFRA, a CFRA to obtain the TA of the target cell may be triggered by the CSC MAC CE. The UE follows the TCI state indicated within the CSC MAC CE after the RA procedure.

[0067] (Analysis) Future wireless communication systems (e.g., Rel. 21 and beyond, 6G systems) are expected to realize advanced services that go beyond 5G NR systems, such as those exemplified below, in order to solve social issues in the 2030s and beyond: • Scalable networks (NW). • Easy-to-operate NW. • Sustainable / resilient NW. • Improved performance (e.g., throughput / capacity) at lower bit costs. • Significant reduction in the cost / complexity / power consumption of cellular networks. • Increased revenue / creation of new value through cellular networks.

[0068] For scalable networks, it is desirable that the basic design of a 6G system be applicable not only to use cases within the 6G system but also to potential new use cases that may arise later. This is because it will be beneficial and practical for features that are expected to be released in the future.

[0069] For easily operable networks, it is desirable to avoid specifying multiple options for the same purpose.

[0070] For sustainable and fast-recovering networks, significant cost and energy consumption reductions are desirable for both the network side and the terminals (user terminals, user equipment (UE)). Furthermore, improved fault tolerance and rapid recovery capabilities against all kinds of events (e.g., operational errors, high traffic, disasters, etc.) are also desirable.

[0071] To realize these services, it is necessary to consider the regulations regarding the carriers through which UE / NW communications will take place, but this consideration has not been sufficient. If this consideration is insufficient, there is a risk that advanced services beyond 5G NR will not be realized.

[0072] Therefore, the inventors conceived a carrier design for future wireless communication systems. It should be noted that in this carrier design, the cell configuration may be the cell-free configuration described above, and is not limited thereto.

[0073] The embodiments of this disclosure will be described in detail below with reference to the drawings. Each wireless communication method according to the embodiments may be applied individually or in combination.

[0074] (Various substitutions) In this disclosure, words enclosed in parentheses () may indicate an explanation of the preceding word (e.g., an explanation of spelling), a paraphrase, a specific example, or supplementary explanation. Also, in this disclosure, words enclosed in square brackets [] may be interpreted as part of the overall meaning of the text, or they may be interpreted as being excluded (ignored). Note that parentheses () and square brackets [] may be used for purposes / meanings other than those described above.

[0075] In this disclosure, "A / B" and "at least one of A and B" may be interpreted as mutually exclusive. In this disclosure, "A / B / C" may mean "at least one of A, B, and C".

[0076] In this disclosure, terms such as notice, activate, deactivate, indicate (or specify), select, configure, update, and determine may be interpreted interchangeably. In this disclosure, terms such as support, control, controllable, operate, and capable of operating may be interpreted interchangeably.

[0077] In this disclosure, Radio Resource Control (RRC), RRC parameters, RRC messages, higher-layer parameters, fields, Information Elements (IE), settings, etc., may be interpreted interchangeably. In this disclosure, Medium Access Control elements (MAC Control Elements (CE)), update commands, activation / deactivation commands, etc., may be interpreted interchangeably.

[0078] In this disclosure, the upper layer signaling may be any or a combination thereof, such as Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, and other messages (e.g., messages from the core network, such as positioning protocol messages (e.g., NR Positioning Protocol A (NRPPPa) / LTE Positioning Protocol (LPP)) messages).

[0079] In this disclosure, MAC signaling may include, for example, MAC Control Elements (MAC CEs) and MAC Protocol Data Units (PDUs). Broadcast information may include, for example, Master Information Blocks (MIBs), System Information Blocks (SIBs), Remaining Minimum System Information (RMSIs), and Other System Information (OSIs).

[0080] In this disclosure, physical layer signaling may be, for example, layer (L)1 / L2 signaling, downlink control information (DCI), uplink control information (UCI), etc.

[0081] In this disclosure, carrier, component carrier (CC), frequency, and band may be interpreted as mutually exclusive.

[0082] In this disclosure, handover, cell switch, Rel. 15 handover, DAPS, [NES]CHO, conditional PSCell addition and change (CPAC), [NES or conditional]LTM, mobility, and RRC reconfiguration with sync may be interpreted as mutually exclusive.

[0083] In this disclosure, the terms first cell, serving cell, source cell, and cell connected to the UE may be interpreted interchangeably. In this disclosure, the terms second cell, candidate cell, target cell, destination cell, and cell not connected to the UE may be interpreted interchangeably.

[0084] In this disclosure, the first frequency / second frequency / fourth frequency [band], the first / second / third carrier frequencies [band], and the detection carrier frequency [band] may be interpreted as mutually interchangeable. In this disclosure, the third frequency [band], the third carrier (data carrier) frequency [band], and the connection carrier frequency [band] may be interpreted as mutually interchangeable.

[0085] (Wireless communication method) <Embodiment A> <<Scenario / Carrier design>> The UE may monitor multiple frequencies (for example, which may be called monitoring frequencies / synchronous rasters) to detect a first carrier (for example, which may be called a perch carrier).

[0086] If a first carrier is detected, the UE may perform a synchronous operation (which may be called a first synchronous operation) and receive / retrieve information (e.g., system information).

[0087] The UE may, based on the received / acquired information (e.g., system information), perform an initial access / random access (RA) procedure on a second carrier (which may be called an anchor carrier) to establish an RRC connection with the NW. At least part of the initial access / random access procedure may be performed on the first carrier.

[0088] The UE may transmit / receive data on a third carrier (which may be called a data carrier, for example) that is set up by signals transmitted / received on a second carrier.

[0089] Please note that the names such as perch carrier, anchor carrier, and data carrier used in this disclosure are merely examples and are not limited to these names.

[0090] <<Monitoring Frequency / Synchronization Raster>> The monitoring frequency / synchronization raster may indicate the frequency position of the synchronization signal block (SSB) that the UE can use to acquire the system.

[0091] In existing NRs (e.g., up to Rel. 18), the frequency position (center frequency) of the synchronization signal block is expressed as N * 1200 kHz + M * 50 kHz (where N is an integer from 1 to 2499, and M is 1, 3, or 5) for frequencies from 0 to 3000 MHz (Frequency Range (FR) 1), and as 3000 MHz + N * 1.44 MHz (where N is an integer from 0 to 14756) for frequencies above 3000 MHz (FR 2).

[0092] Furthermore, during initial access to an existing NR, the order in which the UE searches for synchronized rasters depends on the UE implementation. For efficient searching, a Global Synchronization Channel Number (GSCN) is defined, and the GSCN range is notified to the UE. This GSCN is represented as 3N + (M - 3) / 2 in FR1 and as 7499 + N in FR2.

[0093] In this disclosure, the number of monitoring frequency / synchronous rasters may be more limited (e.g., smaller) than that of existing NRs. In other words, the frequency spacing of the monitoring frequency / synchronous rasters may be wider than that of existing NRs.

[0094] For example, the location of a synchronization raster may be defined based on its relationship to information related to a frequency band (e.g., a frequency band index). The UE may monitor or search for the location of a synchronization raster associated with a frequency band index. Alternatively, the UE may assume that the location of a synchronization raster is associated with a frequency band index, and may monitor or search for the synchronization raster based on that assumption.

[0095] For example, the bandwidth in which a GSCN or synchronous raster is defined may be limited. A UE may monitor or search for the bandwidth in which a GSCN or synchronous raster is defined among the bandwidths supported by the UE. Alternatively, a UE may assume that a GSCN or synchronous raster is defined in only a specific bandwidth among the bandwidths supported by the UE, and may monitor or search for a GSCN or synchronous raster based on that assumption.

[0096] For example, in a given bandwidth, a GSCN or synchronous raster may be defined only at specific frequency positions. For example, in a given bandwidth, a GSCN or synchronous raster may be defined within X Hz (where X is any number) from the lower limit of that bandwidth. A UE may monitor or search for a GSCN or synchronous raster in each of the bandwidths it supports, only at the specific frequency positions where such a GSCN or synchronous raster is defined. Alternatively, a UE may assume that a GSCN or synchronous raster is defined only at specific frequency positions in a given bandwidth, and may monitor or search for a GSCN or synchronous raster based on that assumption.

[0097] This allows for an extension of the time required for cell search per frequency (i.e., the period of the synchronization signal block per frequency), thereby reducing network energy consumption and shortening the time required for initial access.

[0098] The monitoring frequency resources detected by the UE may correspond to potential perch carriers (first carriers).

[0099] <<First Carrier / Perch Carrier>> The first carrier may be a carrier common to multiple UEs.

[0100] The first carrier could be a common carrier regardless of the use case / service / device type, for example.

[0101] In the first carrier, common signals (e.g., synchronization signal blocks / master information blocks / system information blocks) may be transmitted. Furthermore, the transmission and reception of data (e.g., application layer information) is not assumed in the first carrier. Also, the transmission and reception of information relating to a specific UE or a specific group of UEs (e.g., information other than that relating to the second carrier) is not assumed in the first carrier.

[0102] The first carrier (and the signal transmitted in it) may always be kept in the ON state.

[0103] Signals transmitted on the first carrier (e.g., synchronization signal blocks / master information blocks / system information blocks) may include information about an anchor carrier (second carrier) that is available in the system or used by the UE.

[0104] The first carrier may have a frequency lower than a specific value (for example, 800 MHz).

[0105] The first carrier may correspond to a single (base station) beam.

[0106] The UE may perform a first synchronization in the first carrier. The first synchronization may mean a first step / level (e.g., coarse) synchronization among multiple (e.g., two) step / level synchronizations.

[0107] The first carrier may, for example, be included in a coverage band.

[0108] By defining and utilizing the first carrier in this way, it is possible to cover all future use cases and contribute to achieving a scalable network.

[0109] <<Second Carrier / Anchor Carrier>> The second carrier may be a carrier / frequency used for network connection / control.

[0110] The second carrier may be an individual carrier for each UE, for multiple UEs (UE groups), for each use case, or for each service. A UE may determine which second carrier is compatible with its device based on information obtained from the first carrier.

[0111] In the second carrier, at least one of the following transmissions / receptions / operations may occur: - Transmission / reception of a system information block for a specific use case (e.g., enhanced Mobile Broadband (eMBB)); - Connection establishment; - Transmission / reception of a wake-up signal (WUS); - Wake-up receiver (WUR) operation; - Second synchronization; - Information about the third carrier.

[0112] The terms "Wake-up signal (WUS)" and "Wake-up receiver" may be interpreted as "Low-power wake-up signal (LP-WUS)" and "Low-power wake-up receiver (LP-WUR)."

[0113] By using a second carrier to perform LP-WUS / WUR related operations, it is possible to reduce network energy consumption and user energy consumption.

[0114] The second carrier (and the signals transmitted on it) does not have to be always on (it may be in a dormant state). For example, the transmission of signals on the second carrier (DL transmission / UL transmission) may be supported to be performed on demand in response to a wake-up signal / trigger signal.

[0115] The second synchronization may refer to the second step / level (e.g., a more precise) synchronization among multiple (e.g., two) step / level synchronizations. For example, a UE may achieve the first synchronization on the first carrier and the second synchronization on the second carrier.

[0116] The second carrier may be included in the first carrier in certain cases (for example, in the case of a [narrowband] IoT device). Alternatively, the second carrier may be configured as a carrier that overlaps the same frequency band as the first carrier.

[0117] The second carrier may, for example, be included in a coverage band.

[0118] At least one operation performed on the second carrier may also be performed on the first / third carrier. Furthermore, at least one operation performed on the first / third carrier may also be performed on the second carrier.

[0119] <<Third Carrier / Data Carrier>> The third carrier may be a carrier used for transmitting / receiving data.

[0120] The third carrier could be an individual carrier for each UE, for multiple UEs (UE groups), for each use case, or for each service.

[0121] The third carrier (and the signals transmitted on it) does not have to be always on (it may be in a dormant state). For example, the transmission of signals on the third carrier (DL transmission / UL transmission) may be supported to be performed on demand in response to a wake-up signal / trigger signal.

[0122] The third carrier may be included in both the coverage band and the capacity band, for example. The third carrier within the capacity band may be used as a surplus carrier.

[0123] The third career may include the first career.

[0124] UE / NW may use the first carrier as a third carrier only in specific cases. Such specific cases may be, for example, at least one of (re-)initial access, fallback cases, and mobility on the second carrier.

[0125] UE may use / monitor the first carrier as a third carrier. Also, U may use / monitor the first carrier as a third carrier in the case of mobility on the first carrier.

[0126] The first, second, and third carriers corresponding to terrestrial networks (TN) and the first, second, and third carriers corresponding to non-terrestrial networks (NTN) may be defined separately or in common.

[0127] Furthermore, certain devices (for example, devices that do not perform cell search / RRC connectivity (e.g., Ambient IoT (A-IoT))) do not need to use a second carrier.

[0128] Figure 4 shows an example of carrier design in this disclosure. Figure 4 shows a low-frequency band (coverage band) and a high-frequency band (capacity band). In the example shown in Figure 4, after the UE is powered on, the UE performs a cell search using the monitoring frequency. Next, the monitoring frequency resource detected by the UE becomes the perch carrier (first carrier), and the perch carrier receives information about the anchor carrier (second carrier). The UE performs initial access (IA) using at least one of the perch carrier and the anchor carrier. From the cell search to the completion of IA, the UE is in idle mode.

[0129] After initial access is complete, the UE enters RRC connection (CONNECTED) mode. The UE receives information about the data carrier (third carrier) on the anchor carrier. The UE performs additional synchronization on the anchor carrier. The UE transmits / receives data on the data carrier for a specific use case (e.g., eMBB / other purposes).

[0130] In the example shown in Figure 4, if the UE returns to idle mode / inactive mode, RRC reconnection may be performed using LP-WUS / WUR and at least one of mobility operations.

[0131] In the example shown in Figure 4, carriers other than the perch carrier may be on-demand carriers (i.e., carriers that are not always on) from the viewpoint of reducing network energy. For example, at least one of the second carrier (anchor carrier) and the third carrier (data carrier) may support on-demand transmission / setting, where transmission is controlled based on a wake-up signal / trigger signal, while the first carrier (perch carrier) may not support on-demand transmission / setting.

[0132] As an example, the UE may transmit a wake-up / trigger signal based on information about a second carrier received on the first carrier, and receive a signal transmitted on the second carrier in response to the wake-up / trigger signal. As another example, the UE may transmit a wake-up / trigger signal based on information about a third carrier received on the second carrier, and receive a signal transmitted on the third carrier in response to the wake-up / trigger signal.

[0133] In the example shown in Figure 4, the UE may obtain a first synchronization (or information about the first synchronization) on the first carrier and a second synchronization (or information about the second synchronization) on the second carrier. In this case, the UE may perform transmission and reception on the first carrier (or transmission and reception on the first carrier and transmission and reception on a portion of the second carrier) based on the first synchronization, and perform transmission and reception on the second and third carriers (or transmission and reception on a portion of the second carrier and transmission and reception on the third carrier) based on the second synchronization.

[0134] <<Variation>> If the UE enters idle / inactive mode again after RRC connection, it may be assumed that it will use the previous first / second carrier.

[0135] Furthermore, if the UE enters idle / inactive mode again after RRC connection, it may be assumed that synchronization on the previous first / second carrier has been completed.

[0136] The carrier design of this disclosure may be applied to a cell-free configuration as appropriate. For example, the first carrier in this disclosure may correspond to a first cell (e.g., a supercell) or a second cell (e.g., an area). Also, for example, the second carrier in this disclosure may correspond to a first cell (e.g., a supercell) or a second cell (e.g., an area). Also, for example, the third carrier in this disclosure may correspond to a second cell (e.g., an area).

[0137] <Embodiment B0> In Embodiment A (a scenario using the first / second / third carriers), the UE may perform a handover (cell switch).

[0138] The handover may include at least one of the following steps:

[0139] ◆Procedure: The UE reports the L1 / L3 measurement results [based on the reporting settings (RRC IE)]. The measurement results may be RSRP / SINR / RSRQ. The settings may include at least one of the following: RS for measurement, PCI for measurement, and period for measurement / reporting. The report may include at least one of the following: P / SP / AP-CSI report triggered / configured by the base station, event-triggered (UE-initiated) beam report triggered by the UE, and L3 measurement report. The RS measured for the report may be P / SP / AP-RS. The report may be reported per carrier / CC or for multiple CCs / carriers.

[0140] ◆Procedure: The UE receives a handover instruction from the gNB [in response to the report]. The handover instruction may include at least one of the following: a cell switch, a handover command, and an RRC reconfiguration message. The handover instruction may also indicate the cell / cell group to be switched to.

[0141] ◆Procedure: The UE switches the serving cell / MCG / SCG to the designated cell / cell group.

[0142] ◆Procedure: The UE synchronizes with the target cell. This synchronization may include at least one of DL timing synchronization and UL timing synchronization. UL timing synchronization may include timing advance (TA) acquisition.

[0143] According to this embodiment, in scenarios using the first / second / third carriers, the UE / BS can maintain stable communication / connection even if UE movement or changes in the surrounding propagation environment occur.

[0144] <Variations of Embodiment B0> In Embodiment A (scenario using the first / second / third carriers), the UE does not need to perform a handover (cell switch).

[0145] Under specific frequencies / conditions in scenarios using the first / second / third carriers, the UE does not need to perform a handover.

[0146] In scenarios using the first, second, and third carriers, if instructions are received via upper-layer signaling, the UE does not need to perform a handover.

[0147] The UE may perform cell detection / initial access as needed if the quality of the connected cell deteriorates.

[0148] This variation allows for simplified UE operation and reduced RS overhead in scenarios using the first, second, and third carriers. RS overhead is reduced because, by not transmitting an RS for handover (or limiting the frequency of RS transmission for handover), the base station / cell no longer needs to continuously transmit an RS (to be received by the UE as the RS for handover switching) regardless of whether that RS is used within the cell.

[0149] <Supplement to Embodiment B0> At least one of the following first signal and second signal may be used.

[0150] ◆First signal The first signal may be a signal (RS) for a UE in the transmitting cell that transmits the first signal. The first signal may include, for example, a TRS and a CSI-RS for CSI acquisition. Of the [RS] resources of the first signal, transmission of [RS] resources corresponding to beams not used by UEs in the RRC connected state in the transmitting cell may be stopped. This allows the power consumption of the network to be defined and the RS overhead to be reduced.

[0151] In the example in Figure 5A, the first signal is TRS#0 to #7, which refer to SSB#0 to #7 respectively (using the beam as the QCL source RS). If the beam (TCI state) used by the UE in the RRC connection state within the cell transmitting TRS#0 to #7 (which is set / activated for that UE) corresponds only to SSB#0, then the transmission of TRS#1 to #7, excluding TRS#0 corresponding to that beam, can be stopped, and the resources of the stopped TRS#1 to #7 can be used for PDSCH transmission.

[0152] ◆Second signal The second signal may be a mobility RS (mobility RS). The second signal may be an RS for UEs in the surrounding cells of the transmitting cell that transmits the second signal, or an RS for surrounding cell measurements of UEs in the transmitting cell. The second signal may be a DL-RS / periodic (P)-RS. The second signal may include at least one of an SSB and a mobility CSI-RS. The base station may not stop transmitting [RS] resources corresponding to beams not used by UEs in the RRC connected state in the transmitting cell (this may always [periodically] be done).

[0153] In Rel. 18 LTM, to reduce cell switch delay, the TRS resource of a candidate cell can be set before the cell switch command. Since the UE can measure TRS resource #1 before receiving the cell switch command, if base station #2 in cell #2, which is different from cell #1 that transmits TRS resource #1, sets cell #1's TRS resource #1 to a UE in cell #2, base station #1 in cell #1 cannot stop transmitting TRS resource #1, regardless of whether the RRC-connected UE in cell #1 measures TRS resource #1.

[0154] In the example in Figure 5B, the second signal is TRS #0 to #7, which reference SSB #0 to #7 respectively (using the beams as QCL source RS). If the beams (TCI state) for all SSB #0 to #7 referenced by TRS #0 to #7 are used by a UE in an RRC connected state (set / activated for that UE), then TRS #0 to #7 corresponding to all beams cannot be shut down.

[0155] <Embodiment B1> The connecting carrier may be a carrier used for transmitting / receiving data at the switching destination. The connecting carrier may be a third carrier, or a third carrier within a frequency range higher than a specific frequency (e.g., 7125 MHz / 24250 MHz) (a second frequency range, e.g., FR2).

[0156] The detected carrier may be the first / second carrier, or a carrier (first / second / third carrier) within a frequency range lower than a specific frequency (first frequency range, e.g., FR1). The detected carrier may be the same as the connected carrier, or may be within the band of the connected carrier.

[0157] This embodiment may be based on at least one of the following embodiments B1-x.

[0158] <<Embodiment B1-1>> The handover destination does not have to be based on the channel quality / beam information of the connected carrier. The handover destination may be a peripheral cell.

[0159] A handover may be performed based on the measurement results of L1 / L3 of the detected carrier.

[0160] The UE may report the L1 / L3 measurement results of the detected carrier and receive a handover instruction. In this case, RS overhead can be reduced because transmission of the second signal on [all] carriers is not required. After RRC connection is established on the switched carrier, the UE may obtain resource (frequency / beam) information of the switched connected carrier.

[0161] Since the UE does not know the channel quality / beam information of the connected carrier at the time of handover, it may obtain resource (frequency / beam) information / indication of the connected carrier after performing a CSI report [including L1 beam report] of the detected carrier.

[0162] The detection carrier may be a bandwidth that can ensure coverage within the first frequency range (for example, the 700 / 800 MHz band). The bandwidth of the connected carrier may be different from that of the detection carrier.

[0163] During a handover, UL timing synchronization for a specific beam on the destination carrier may not be required. The specification may define, or it may be configured, that the UE does not perform PRACH transmission on the destination carrier [band].

[0164] A PRACH transmission [on the connecting carrier] for handover may not be performed. A PRACH transmission [on the detection carrier] for handover may be performed.

[0165] During handover, timing synchronization may be performed for the cells, but timing synchronization may not be performed for the beams.

[0166] If the subcarrier spacing (SCS) of the detection carrier differs from that of the connecting carrier, a PRACH transmission may be performed on the connecting carrier. The TA value of the connecting carrier may be determined / indicated by this PRACH transmission. If the SCS of the detection carrier differs from that of the connecting carrier, the indicated TA value may correspond to a specific SCS. The specific SCS may be the minimum or maximum SCS, or it may be the SCS of the detection carrier. The UE may determine the TA value of the connecting carrier from the indicated TA value according to a rule. For example, if the SCS of the connecting carrier is a times the specific SCS, the TA value of the connecting carrier may be 1 / a times the indicated TA value.

[0167] Figure 6 shows an example of the handover procedure in Embodiment B1-1 when using a perch carrier, anchor carrier, and data carrier.

[0168] In the perch carrier of cell #1 having PCI #1, a periodic RS #1 is transmitted. RS #1 may be at least one of an SSB and a mobility CSI-RS. In the perch carrier of cell #2 having PCI #2, a periodic RS #2 is transmitted. RS #2 may be at least one of an SSB and a mobility CSI-RS.

[0169] A UE in RRC connection state in cell #1 (the current cell, the cell from which the switchover originates) measures RS#1 on the perch carrier of cell #1 and RS#2 on the perch carrier of cell #2 (the candidate cell, the cell to which the switchover originates), and transmits a CSI report showing the measurement results on the data carrier of cell #1. Subsequently, the UE receives a handover instruction from cell #1 to cell #2 on the data carrier of cell #1.

[0170] Based on the handover instruction, the UE establishes an RRC connection to cell #2 using cell #2's anchor carrier. Once the UE establishes the RRC connection to cell #2, it transmits and receives data using cell #2's data carrier.

[0171] <<Embodiment B1-2>> The handover destination may be based on the channel quality / beam information of the connected carrier.

[0172] Handover may be performed based on the L1 / L3 measurement results of the connected carrier.

[0173] The UE may report the L1 / L3 measurement results of the connected carrier [as a CSI report] and receive a handover instruction.

[0174] Transmission of a second signal (mobility RS) in the connecting carrier [band] may be required. Handover based on the connecting carrier's channel quality / beam information allows for the selection of an appropriate cell / beam as the switching destination.

[0175] When a mobility CSI-RS is used and an SSB is transmitted on a detection carrier (e.g., a first carrier), monitoring of the mobility CSI-RS may be specified in the specifications or configured by higher-layer signaling, even if the UE is unable to detect the SSB being QCL'd with the mobility CSI-RS.

[0176] Variations: The second signal (Mobility RS, SSB, Mobility CSI-RS) may be transmitted only on specific configured connection carriers. The SCS may be the same across multiple connection carriers. In this case, RS overhead can be reduced, UL synchronization on a specific connection carrier can be used on other connection carriers, and resources for PRACH transmission on connection carriers can also be reduced.

[0177] If the UE is connected via RRC to the destination connecting carrier, the destination detection carrier / connecting carrier may provide the UE with the connecting carrier's frequency / beam resource information. At the time of handover, the base station knows the channel quality / beam information of the destination cell's connecting carrier, and therefore can provide the UE with the destination connecting carrier's frequency / beam resource information without providing the UE with the connecting carrier's CSI report (including the L1 beam report).

[0178] In this case, the UE may require UL timing information for the specific beam to be switched to, and PRACH transmission in the connected carrier [band] may be performed as appropriate to the specification, or may be configured by higher-layer signaling. The UE may perform beam-level UL timing synchronization [in addition to cell-level UL timing synchronization].

[0179] Variation: The UE may transmit a PRACH transmission for the DL signal corresponding to a specific beam of the connected carrier on a different carrier (detection carrier). This procedure relates to Embodiment B1-3 described later.

[0180] Figure 7 shows example 1 of the handover procedure in Embodiment B1-2 when using an anchor carrier and a data carrier. Example 1 of the procedure may also be applied to RACH-based LTM.

[0181] In the data carrier of cell #1, which has PCI #1, a periodic RS #1 is transmitted. RS #1 may be at least one of SSB and mobility CSI-RS. In the data carrier of cell #2, which has PCI #2, a periodic RS #2 is transmitted. RS #2 may be at least one of SSB and mobility CSI-RS.

[0182] A UE in RRC connection state in cell #1 (the current cell, the cell from which the switchover originates) measures RS#1 on the data carrier of cell #1 and RS#2 on the data carrier of cell #2 (the candidate cell, the cell to which the switchover originates), and transmits a CSI report showing the measurement results on the data carrier of cell #1. Subsequently, the UE receives a handover instruction from cell #1 to cell #2 on the data carrier of cell #1.

[0183] Based on the handover instruction, the UE establishes an RRC connection to cell #2 using cell #2's anchor carrier. Once the UE establishes the RRC connection to cell #2, it transmits and receives data using cell #2's data carrier.

[0184] Figure 8 shows an example of the handover procedure 2 in Embodiment B1-2 when using an anchor carrier and a data carrier.

[0185] RS#1, RS#2, CSI report, and handover instructions are the same as in Procedure Example 1.

[0186] During a handover, the UE does not need to read (or receive) the perch carrier / anchor carrier of the destination cell. In this case, the UE may receive resource allocation (scheduling) information for sending / receiving data from the destination cell (cell #1). Procedure example 2 may also be applied to RACH-less LTM.

[0187] Based on the handover instruction, the UE establishes an RRC connection to cell #2 using the data carrier of cell #2. Once the UE establishes the RRC connection to cell #2, it transmits and receives data using the data carrier of cell #2.

[0188] <<Embodiment B1-3>> The UE may receive a DL signal corresponding to a specific beam of the connected carrier in the connected carrier [band]. At least one of the PRACH transmission and RAR reception of the DL signal may be based on at least one of the following several steps x.

[0189] <<<Procedure A>>> The UE may transmit at least one PRACH transmission and RAR reception for a DL signal corresponding to a specific beam of the connected carrier in the connected carrier [band].

[0190] In this case, the synchronization accuracy between the connecting carrier and the detection carrier does not need to be considered. When the base station determines the TA offset based on the reception result of the PRACH, synchronization is required between the DL signal of the connecting carrier and the carrier [band] of the PRACH transmission. The UE may transmit the PRACH on the connecting carrier [band] and receive the corresponding RAR on the connecting carrier [band].

[0191] Figure 9 shows an example of the operation of the switching target cell in the example procedure A of Embodiment B1-3.

[0192] In the data carrier of cell #2, periodic RS #1 to #4 are transmitted. RS #1 to #4 may be at least one of SSB and mobility CSI-RS. RS #1 to #4 may each use beams #1 to #4.

[0193] Based on the reception of at least one of RS#1 to #4, the UE receives a PRACH on the data carrier of cell #2. The PRACH may be transmitted using one of the beams (PRACH occasions) #1 to #4, which correspond to RS#1 to #4, respectively.

[0194] Based on the transmission of PRACH, the UE receives RAR on the data carrier of cell #2. The RAR may be transmitted using one of beams #1 to #4, which correspond to RS #1 to #4, respectively.

[0195] <<<Procedure B>>> The UE may transmit at least one PRACH transmission and RAR reception for a DL signal corresponding to a specific beam of the connected carrier in a band of a carrier (detection carrier) other than the connected carrier.

[0196] The resource overhead of transmitting a PRACH is large. In this case, it is possible to avoid transmitting a PRACH on the connecting carrier, thereby preventing the increase in overhead due to the PRACH on the connecting carrier. The connecting carrier and the PRACH-transmitting carrier may be synchronized. This synchronization may be based on at least one of the following steps B-x.

[0197] ◆Procedure B-1 The UE may transmit a PRACH on the detection carrier [band] and receive the corresponding RAR on the connecting carrier [band]. This procedure avoids overhead due to the PRACH on the connecting carrier.

[0198] Figure 10 shows an example of the operation of the switching target cell in the example procedure B-1 of Embodiment B1-3.

[0199] Similar to the example procedure in procedure A, periodic RS#1 to #4 are transmitted in the data carrier of cell #2.

[0200] Based on the reception of at least one of RS#1 to #4, the UE receives a PRACH on the anchor carrier of cell #2. The PRACH may be transmitted using one of the beams (PRACH occasions) #1 to #4, which correspond to RS#1 to #4, respectively.

[0201] Based on the transmission of PRACH, the UE receives RAR on the data carrier of cell #2. The RAR may be transmitted using one of beams #1 to #4, which correspond to RS #1 to #4, respectively.

[0202] ◆Procedure B-2 The UE may transmit a PRACH on the detection carrier [band] and receive the corresponding RAR on the detection carrier [band]. This procedure avoids overhead on the connected carrier due to PRACH and RAR.

[0203] Figure 11 shows an example of the operation of the switching target cell in the example procedure B-2 of Embodiment B1-3.

[0204] Similar to the example procedure in procedure A, periodic RS#1 to #4 are transmitted in the data carrier of cell #2.

[0205] Based on the reception of at least one of RS#1 to #4, the UE receives a PRACH on the anchor carrier of cell #2. The PRACH may be transmitted using one of the beams (PRACH occasions) #1 to #4, which correspond to RS#1 to #4, respectively.

[0206] Based on the transmission of PRACH, the UE receives the RAR on the anchor carrier of cell #2. The RAR may be transmitted using one of the beams #1 to #4, which correspond to RS #1 to #4, respectively.

[0207] <Embodiment B2> The perch carrier's [frequency] band may be based on at least one of the following embodiments B2-x.

[0208] <<Embodiment B2-1>> The frequency [band] of the perch carrier may be specified in the specifications. For example, the perch carrier band may be the 700 MHz band. The frequency [band] of the perch carrier may be specified on a country-by-country / operator-by-operator basis.

[0209] <<Embodiment B2-2>> The perch carrier frequency [band] may be selected by the operator / base station / NW. Candidate perch carrier frequencies [bands] may be specified in the specifications. The UE may detect the SSB frequency [band] (perch carrier) using a raster mechanism (SS frequency raster, synchronous raster) similar to that of the NR. The SS frequency raster may be defined by the intervals between possible SS locations. The perch carrier frequency [band] may be based on at least one of several features x below.

[0210] <<<Feature A>>> Between multiple PCIs / cells, the perch carrier frequency [band] may be common or different. The perch carrier frequency [band] in a PCI / cell may be determined / set by the NW / base station. If the SSB frequency [band] may differ between the source and destination, the UE may use the SS frequency raster mechanism to detect the destination SSB. The UE may attempt to detect the destination SSB in the same frequency [band] as the source SSB frequency [band], and if the SSB is not detected, it may attempt to detect the SSB in a different frequency [band] / raster.

[0211] When the perch carrier frequency [band] is common among multiple PCI / cells, the raster (SS frequency raster, synchronization raster) in the perch carrier frequency [band] may be common or different among the multiple PCI / cells.

[0212] <<<Feature B>>> The perch carrier frequency [band] may be common among multiple PCI / cells. The perch carrier frequency [band] in a PCI / cell may be specified in the specifications or set by upper-layer signaling. In this case, since the SSB (perch carrier) frequency [band] is the same between the source and destination, the UE may detect / measure the SSB at the same frequency [band] as the source SSB frequency [band], or in the peripheral band within the source SSB frequency [band]. In other words, the UE does not need to use the SS frequency raster mechanism to detect the destination SSB, which reduces the UE load and shortens the handover time.

[0213] The data carrier frequency [band] may be the same between the source and destination stations. The data carrier frequency [band] may be specified in the specifications or set / instructed by the base station.

[0214] For example, if 3G is used on a specific frequency in a particular region / prefecture, and perch carriers are not used, then perch carriers may be transmitted only on bands where perch carriers can be transmitted nationwide.

[0215] In embodiment B2-2, another second signal / RS, such as CSI-RS, may be used instead of SSB.

[0216] When the second signal (RS for mobility) is transmitted on the anchor carrier / data carrier, the perch carrier in embodiment B2 may be replaced (or reinterpreted) with the anchor carrier / data carrier.

[0217] According to this embodiment, the UE can identify a suitable carrier for the mobility RS (SSB / CSI-RS) during the handover.

[0218] <Embodiment B3> The frequency [band] of the anchor carrier may be based on at least one of the following embodiments B3-x.

[0219] <<Embodiment B3-1>> The frequency [band] of the anchor carrier may be specified in the specifications. For example, the band of the anchor carrier may be the 700 MHz band. The frequency [band] of the anchor carrier may be specified on a country-by-country / operator-by-operator basis.

[0220] <<Embodiment B3-2>> The anchor carrier band may be selected by the operator / base station / NW. Candidate anchor carrier frequencies [bands] may be specified in the specifications. The UE may be notified of the anchor carrier frequency [band] by receiving SSB / system information [on the perch carrier]. Reception of SSB / system information may include at least one of PSS / SSS detection, PBCH-DMRS measurement, PBCH reception, and PBCH-based SIB1 reception. The anchor carrier frequency [band] may be based on at least one of several features x below.

[0221] <<<Feature A>>> Between multiple PCIs / cells, the anchor carrier frequency [band] may be common or different. The anchor carrier frequency [band] in a PCI / cell may be determined / set by the NW / base station. If the anchor carrier frequency [band] may differ between the source and destination, the UE may detect the destination SSB and identify / determine the anchor carrier frequency [band] based on that SSB.

[0222] <<<Feature B>>> The anchor carrier frequency [band] may be common among multiple PCI / cells. The anchor carrier frequency [band] in a PCI / cell may be specified in the specifications or set by upper-layer signaling. In this case, since the anchor carrier frequency [band] is the same between the source and destination, the UE can identify / determine the anchor carrier frequency [band] even if it omits part of the receiving operation at the destination (without detecting the destination's SSB). This can reduce the load on the UE and shorten the handover time.

[0223] The receiving operation at the switching destination may include at least one of the following procedures, similar to those for NR.

[0224] ◆Procedure 1: PSS detection. This procedure may include at least one of the following procedures 1-x: —◆Procedure 1-1: Detection of PCI portion. —◆Procedure 1-2: Detection of OFDM symbol timing. —◆Procedure 1-3: [Coarse] frequency synchronization.

[0225] ◆Step 2: SSS detection. This step may include at least one of the following steps 2-x: —◆Step 2-1: PCI detection.

[0226] ◆Step 3: PBCH-DMRS detection. This step may include at least one of the following steps 3-x: —◆Step 3-1: Detection of part of the SSB index within 5 ms of half of the wireless frame.

[0227] ◆Procedure 4: PBCH decoding. This procedure may include at least one of the following procedures 4-x: —◆Procedure 4-1: Detection of system frame number (SFN) and wireless frame timing (SSB index). —◆Procedure 4-2: Detection of configuration information for SIB1 reception. —◆Procedure 4-3: Determination of whether the UE can camp on to that cell.

[0228] The data carrier frequency [band] may be the same between the source and destination stations. The data carrier frequency [band] may be specified in the specifications or set / instructed by the base station.

[0229] For example, if 3G is used on a specific frequency in a particular region / prefecture, and anchor carriers are not used, then anchor carriers may be transmitted only on bands where they can be transmitted nationwide.

[0230] In embodiment B3-2, another second signal / RS, such as CSI-RS, may be used instead of SSB.

[0231] According to this embodiment, the UE can identify a suitable anchor carrier during handover.

[0232] <Embodiment B4> The relationship between the perch carrier and the anchor carrier may be based on at least one of the following embodiments B4-x.

[0233] <<Embodiment B4-1>> The correspondence between the perch carrier and the anchor carrier may be one-to-one. There may be one anchor carrier for one perch carrier. The UE may identify one anchor carrier by receiving / detecting the SSB on the perch carrier.

[0234] Figure 12 shows an example of the operation of the switching destination cell in the procedure example of Embodiment B4-1. In this procedure example, the UE may, during the handover, receive the SSB on the switching destination perch carrier, identify / determine the frequency [band] of the anchor carrier based on that SSB, and perform transmit / receive [in the initial access / RA / RRC connection procedure] on that anchor carrier.

[0235] <<Embodiment B4-2>> The correspondence between the perch carrier and the anchor carrier may be one-to-many. Multiple anchor carriers may exist for one perch carrier. The UE may identify multiple anchor carriers by receiving / detecting SSB on the perch carrier.

[0236] Which of multiple anchor carriers is used for initial access / RRC connection may be determined based on at least one of the following: broadcast information, upper-layer signaling, UE capability information, UE ID, UE determination procedure / implementation, random number, scramble ID, and PCI. For example, if multiple anchor carriers for a received perch carrier are in bands #1 and #2, and the RF bandwidth (BWP size supported by the UE) is X or greater, band #1 may be used as the anchor carrier; otherwise, band #2 may be used as the anchor carrier. This allows anchor carriers for eMBB (UEs supporting bandwidth X or greater) and anchor carriers for IoT (UEs not supporting bandwidth X or greater) to be distributed across different bands. Here, band #2 may be in the same band as the perch carrier. By distributing anchor carriers across multiple bands, strain on PRACH resources in a single anchor carrier can be avoided.

[0237] At least one of Msg1 to Msg4 may be transmitted / received on the anchor carrier. Msg1 to Msg4 may be transmitted / received on the anchor carrier. Msg3 to Msg4 may be transmitted / received on the anchor carrier. In this case, Msg2 may notify the anchor carrier.

[0238] Figure 13 shows an example of the operation of the switching destination cell in the procedure example of Embodiment B4-2. In this procedure example, during the handover, the UE may receive the SSB on the switching destination perch carrier, identify / determine the frequencies [bands] (band #1 and band #2) of a plurality of anchor carriers based on the SSB, identify / determine one anchor carrier from the frequencies [bands] of the plurality of anchor carriers, and perform transmission / reception [in the initial access / RA / RRC connection procedure] on that anchor carrier.

[0239] <<Embodiment B4-3>> The correspondence between the parch carrier and the anchor carrier may be a many-to-one correspondence. There may be one anchor carrier for multiple parch carriers. The UE may receive / detect one parch carrier from among the multiple parch carriers and, in the same manner as in Embodiment B4-1, identify one anchor carrier based on that parch carrier.

[0240] <<Embodiment B4-4>> The correspondence between the parch carrier and the anchor carrier may be many-to-many. There may be multiple anchor carriers for multiple parch carriers. The UE may receive / detect one of the multiple parch carriers and, in the same manner as in Embodiment B4-2, identify one anchor carrier from the multiple anchor carriers corresponding to that parch carrier.

[0241] <<Relationship between SSB and PRACH>> SSB may be transmitted on a perch carrier, and PRACH may be transmitted on an anchor carrier.

[0242] If both the perch carrier and anchor carrier are in a band lower than a specific frequency (e.g., 4 GHz, 7125 MHz) (a lower frequency band within FR1), the beams of the perch carrier and anchor carrier may not need to be considered. There may be a one-to-one correspondence between SSB, PRACH occasions / resources, and the RAR receive window.

[0243] If both the perch carrier and anchor carrier are in a band higher than a specific frequency (a high-frequency band within FR1), the beams of the perch carrier and anchor carrier may be considered. SSBs, PRACH occasions / resources, and RAR receiving windows may correspond M to M (M SSBs, M PRACH occasions / resources, and M RAR receiving windows may be associated with each other). The maximum number of M in FR1 of NR is 8. The maximum number of M in FR2 of NR is 64.

[0244] When perch carrier and anchor carrier beams are considered, SSB, PRACH, and [RAR and] may be in the same band. If M > 1, the constraint that SSB, PRACH, and [RAR and] are in the same band may be specified.

[0245] Figure 14 shows an example of the relationship between DL-RS and PRACH when M=1, where PRACH is transmitted on an anchor carrier. In this example, one DL-RS (SSB) is associated with one PRACH occasion / resource. The UE receives / detects the SSB on the perch carrier, identifies the PRACH occasion / resource / beam corresponding to that SSB, and transmits the PRACH using that occasion / resource / beam on the anchor carrier.

[0246] Figure 15 shows an example of the relationship between DL-RS and PRACH when M > 1, where PRACH is transmitted on an anchor carrier. In this example, M = 4, and the four DL-RSs (SSB #1 to #4) are associated with the four PRACH occasions / resources / beams #1 to #4, respectively. The UE receives / detects SSB #1 on the perch carrier, identifies the PRACH occasion / resource / beam #1 corresponding to that SSB #1, and transmits the PRACH using that occasion / resource / beam #1 on the anchor carrier.

[0247] Variation: If SSB, PRACH, and RAR are in different bands, the UE does not have to use the selected / detected SSB beam for PRACH transmission. In this case, the UE may determine a beam (RS index) based on the selected / detected SSB and use that beam for PRACH transmission.

[0248] Variation: SSB may be transmitted on a perch carrier, and PRACH may be transmitted on a perch carrier.

[0249] Figure 16 shows an example of the relationship between DL-RS and PRACH when M=1, where PRACH is transmitted on a perch carrier. In this example, one DL-RS (SSB) is associated with one PRACH occasion / resource. The UE receives / detects the SSB on the perch carrier, identifies the PRACH occasion / resource / beam corresponding to that SSB, and transmits the PRACH using that occasion / resource / beam on the perch carrier. One PRACH occasion / resource / beam may be associated with one RAR window / beam. The UE may identify the RAR window / beam corresponding to the PRACH occasion / resource / beam and receive the RAR on the anchor carrier using that window / beam.

[0250] Figure 17 shows an example of the relationship between DL-RS and PRACH when M > 1, where PRACH is transmitted on a perch carrier. In this example, M = 4, and the four DL-RSs (SSB #1 to #4) are associated with the occasions / resources / beams #1 to #4 of the four PRACHs, respectively. The UE receives / detects SSB #1 on the perch carrier, identifies the occasion / resource / beam #1 of the PRACH corresponding to that SSB #1, and transmits the PRACH using that occasion / resource / beam #1 on the perch carrier. The occasions / resources / beams #1 to #4 of the four PRACHs may also be associated with the windows / beams #1 to #4 of the four RARs, respectively. The UE may identify the window / beam #1 of the RAR corresponding to the occasion / resource / beam #1 of PRACH and receive the RAR on the anchor carrier using that window / beam #1.

[0251] In embodiment B4, another second signal / RS, such as CSI-RS, may be used instead of SSB.

[0252] <Supplement> <<Notification of Information to UE>> In the embodiments described above, notification of any information from the Network (NW) (e.g., Base Station (BS)) to the UE (in other words, reception of any information from the BS at the UE) may be performed using physical layer signaling (e.g., DCI), higher layer signaling (e.g., RRC signaling, MAC CE), specific signals / channels (e.g., PDCCH, PDSCH, reference signal), or a combination thereof.

[0253] If the above notification is made by a MAC CE, the MAC CE may be identified by the inclusion of a new Logical Channel ID (LCID) not defined in existing standards in the MAC subheader.

[0254] If the above 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 the Cyclic Redundancy Check (CRC) bits assigned to the DCI, or the format of the DCI.

[0255] Furthermore, the notification of arbitrary information to the UE in the above-described embodiment may be periodic, semi-persistent, or aperiodic.

[0256] In the embodiments described above, the UE may receive at least one piece of information (QCL information) from the NW from among several of the following QCL rules / QCL types: ◆ QCL type A (Doppler shift, Doppler spread, mean delay, and delay spread) ◆ QCL type B (Doppler shift and Doppler spread) ◆ QCL type C (Doppler shift and mean delay) ◆ QCL type D (spatial reception parameters)

[0257] In the embodiments described above, the QCL source RS for each QCL type may be at least one of the following RSs: ◆SSB ◆CSI-RS with / without repetition ◆TRS ◆DMRS for PDCCH / PDSCH

[0258] In the embodiments described above, information from the network may be set / instructed by the following methods: ◆ Common to multiple UEs, or individual to a UE ◆ Cell-specific, or common to multiple cells ◆ Per UE / Per CC / Per BWP / Per band / Per cell / Per cell group (CG)

[0259] <<Notification of Information from UE>> Notification of any information from the UE to the NW in the embodiments described above (in other words, transmission / reporting 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), specific signals / channels (e.g., PUCCH, PUSCH, PRACH, reference signals), or a combination thereof.

[0260] If the above notification is made by a MAC CE, the MAC CE may be identified by the inclusion of a new LCID not specified in existing standards in the MAC subheader.

[0261] If the above notice is made by the UCI, the notice may be transmitted using PUCCH or PUSCH.

[0262] Furthermore, the notification of any information from the UE in the above-described embodiment may be periodic, semi-persistent, or aperiodic.

[0263] <<Regarding the Application of Each Embodiment>> In UE / BS, specific (one or more) processes / operations / controls / assumptions / information for at least one of the embodiments described above may be applied (or used) if any or more of the following conditions are met: - A higher-layer parameter indicating the specific process / operation / control / assumption / information is set. - The specific process / operation / control / assumption / information is determined based on the relevant higher-layer parameter. - The specific process / operation / control / assumption / information is designated / activated / triggered by MAC CE / DCI / UCI / Resource / Channel / RS. - A specific UE capability indicating (or related to) the specific process / operation / control / assumption / information is reported or supported. - The application of the specific process / operation / control / assumption / information is determined based on specific conditions.

[0264] The above-mentioned specific UE capabilities may include at least one of the following: - Supporting the above-mentioned specific processing / operation / control / assumment / information; - Supporting monitoring frequencies / first carrier / second carrier / third carrier (and related operations).

[0265] Furthermore, the above-mentioned specific UE capability may be a capability that applies across all frequencies (commonly regardless of frequency), a capability per frequency (e.g., one or a combination thereof, such as cell, band, band combination, BWP, component carrier, etc.), a capability per frequency range (e.g., Frequency Range 1 (FR1), FR2, FR3, FR4, FR5, FR2-1, FR2-2), a capability per subcarrier spacing (SCS), or a capability per feature set (FS) or feature set per component-carrier (FSPC).

[0266] Furthermore, the specific UE capabilities described above may be capabilities that apply across all duplexing schemes (common to all duplexing schemes regardless of the duplexing scheme), or they may be capabilities specific to each duplexing scheme (e.g., Time Division Duplex (TDD), Frequency Division Duplex (FDD)).

[0267] If the above conditions are not met, UE / BS may follow the behavior specified in existing 3GPP releases.

[0268] Information on whether one or more of the above embodiments / options / choices / examples apply / are used, or which of the above embodiments / options / choices / examples apply / are used, may be based on several of the following methods: ◆ The information is set by one or more higher layer parameters / RRC IEs. ◆ The information is determined by one or more relevant higher layer parameters / RRC IEs. ◆ The information is indicated by MAC CE / DCI. ◆ The information is determined / set / indicated based on one or more UE capabilities. ◆ The information is described / defined in the specification. ◆ The information is based on conditions described / defined in the specification. ◆ The information is determined by a combination of several of the above information. For example, the information is determined by the setting / indication of higher layer parameters / MAC CE / DCIs and reported by UE capabilities.

[0269] The above multiple embodiments / options / choices may be combined into a single embodiment / option / choice.

[0270] In the embodiments described above, the measured RS may be a QCL source RS in an active TCI state / indicated / unified TCI state.

[0271] (Note) The following inventions are added with respect to one embodiment of the present disclosure. [Note 1] A terminal having: a receiving unit that receives a first downlink signal on a first frequency of a first cell and a second downlink signal on a second frequency of a second cell; and a control unit that controls a handover from the first cell to the second cell based on the first downlink signal and the second downlink signal, and controls the transmission and reception of data on a third frequency of the second cell. [Note 2] The terminal according to Note 1, wherein the second frequency is different from the third frequency. [Note 3] The terminal according to Note 1 or Note 2, wherein the second frequency is equal to the first frequency. [Note 4] The terminal according to any one of Notes 1 to 3, wherein the control unit controls the transmission of a physical random access channel on a fourth frequency based on the second downlink signal.

[0272] (Wireless Communication System) The configuration of a wireless communication system according to one embodiment of this disclosure will be described below. In this wireless communication system, communication is performed using any of the wireless communication methods according to the above embodiments of this disclosure, or a combination thereof.

[0273] Figure 18 shows an example of a schematic configuration of a wireless communication system according to one embodiment. The wireless communication system 1 (which may also be simply called system 1) may be a system that realizes communication using Long Term Evolution (LTE), 5th generation mobile communication system New Radio (5G NR), etc., as specified by the Third Generation Partnership Project (3GPP).

[0274] Furthermore, the wireless communication system 1 may 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)), and the like.

[0275] In EN-DC, the LTE (E-UTRA) base station (eNB) is the Master Node (MN), and the NR base station (gNB) is the 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.

[0276] The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity where both MN and SN are NR base stations (gNB) (NR-NR Dual Connectivity (NN-DC))).

[0277] The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with relatively wide coverage, and base stations 12 (12a-12c) located within the macrocell C1 that form a small cell C2 that is narrower than the macrocell C1. User terminals 20 may be located within at least one cell. The arrangement, number, shape, size, etc., of each cell and user terminal 20 are not limited to the configuration shown in the figure. Hereinafter, when base stations 11 and 12 are not distinguished, they will be collectively referred to as base station 10.

[0278] The wireless communication system 1 may utilize Multi Input Multi Output (MIMO). For example, one cell may be formed by one antenna / base station 10, or by multiple antennas / base stations 10. One [virtual] cell (which may be called a supercell, for example) may be composed of multiple [virtual] cells (which may be called subcells, for example). A supercell may correspond to a cell with a fixed physical range, and a subcell may correspond to a cell whose physical range fluctuates quasi-statically / dynamically. In this case, the wireless communication system 1 may be called a cell-free system.

[0279] 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 (CC) and Dual Connectivity (DC).

[0280] Each CC may be included in at least one of the first frequency band (Frequency Range 1 (FR1)) and the second frequency band (Frequency Range 2 (FR2)). A macrocell C1 may be included in FR1, and a 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 above 24 GHz. Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may be in a frequency band higher than FR2.

[0281] Furthermore, the user terminal 20 may communicate in each CC using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD).

[0282] Multiple base stations 10 may be connected by wire (e.g., optical fiber compliant with Common Public Radio Interface (CPRI), X2 / Xn interface, etc.) or wireless (e.g., NR communication). For example, when NR communication is used as a backhaul between base stations 11 and 12, base station 11, which is the upstream station, may be called an Integrated Access Backhaul (IAB) donor, and base station 12, which is the relay station, may be called an IAB node.

[0283] Base station 10 may be connected to the core network 30 via other base stations 10 or directly. The core network 30 may include at least one of the following: Evolved Packet Core (EPC), 5G Core Network (5GCN), Next Generation Core (NGC), etc.

[0284] The core network 30 may include network functions (NF) such as User Plane Function (UPF), Access and Mobility Management Function (AMF), Session Management Function (SMF), Unified Data Management (UDM), Application Function (AF), Data Network (DN), Location Management Function (LMF), and Operation, Administration and Maintenance (Management) (OAM). Multiple functions may be provided by a single network node. Furthermore, communication with an external network (e.g., the Internet) may occur via the DN.

[0285] The user terminal 20 may be a terminal that supports at least one of the following communication methods: LTE, LTE-A, 5G, etc.

[0286] In the wireless communication system 1, an orthogonal frequency division multiplexing (OFDM)-based wireless access scheme may be used. 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-OFDM), etc., may be used in at least one of the downlink (DL) and uplink (UL).

[0287] The wireless access method may also be called a waveform. In wireless communication system 1, other wireless access methods (for example, other single-carrier transmission methods, other multi-carrier transmission methods) may be used for the UL and DL wireless access methods.

[0288] In the wireless communication system 1, a Physical Downlink Shared Channel (PDSCH), a Broadcast Channel (PBCH), or a Physical Downlink Control Channel (PDCCH) may be used as the downlink channel, which is shared by each user terminal 20.

[0289] Furthermore, in the wireless communication system 1, the uplink channel may include a Physical Uplink Shared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH), a Physical Random Access Channel (PRACH), or the like, all of which are shared by each user terminal 20.

[0290] User data, higher-layer control information, and System Information Blocks (SIBs) are transmitted via PDSCH. User data and higher-layer control information may also be transmitted via PUSCH. Furthermore, Master Information Blocks (MIBs) may be transmitted via PBCH.

[0291] Lower-layer control information may be transmitted by PDCCH. The lower-layer control information may include, for example, Downlink Control Information (DCI) which includes scheduling information for at least one of PDSCH and PUSCH.

[0292] Furthermore, the DCI that schedules PDSCH may be called DL assignment, DL DCI, etc., and the DCI that schedules PUSCH may be called UL grant, UL DCI, etc. Furthermore, PDSCH may be read as DL data, and PUSCH may be read as UL data.

[0293] PDCCH detection may utilize a Control Resource Set (CORESET) and a search space. A CORESET corresponds to the resources used to search for DCIs. A search space corresponds to the search area and search method for PDCCH candidates. A single CORESET may be associated with one or more search spaces. A UE may monitor CORESETs associated with a given search space based on the search space configuration.

[0294] A single search space may correspond to one or more PDCCH candidates corresponding to aggregation levels. One or more search spaces may be referred to as a search space set. In this disclosure, "search space," "search space set," "search space configuration," "search space set configuration," "CORESET," and "CORESET configuration" may be interpreted interchangeably.

[0295] PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), delivery acknowledgment information (for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR). PRACH may transmit a random access preamble for establishing a connection with the cell.

[0296] In this disclosure, downlinks, uplinks, etc., may be expressed without the prefix "link." Also, the prefix "physical" may be omitted from the names of various channels.

[0297] 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, the DL-RS may include 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.

[0298] 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 SS (PSS, SSS) and PBCH (and DMRS for PBCH) may be called an SS / PBCH block, SS Block (SSB), etc. Note that SS, SSB, etc. may also be called reference signals.

[0299] Furthermore, in the wireless communication system 1, the uplink reference signal (UL-RS) may include a sounding reference signal (SRS), a demodulation reference signal (DMRS), etc. The DMRS may also be called a user-specific reference signal (UE-specific Reference Signal).

[0300] (Base Station) Figure 19 shows an example of the configuration of a base station according to one embodiment. The base station 10 includes a control unit 110, a transmitting / receiving unit 120, a transmitting / receiving antenna 130, and a transmission line interface 140. Note that one or more of the control unit 110, the transmitting / receiving unit 120, the transmitting / receiving antenna 130, and the transmission line interface 140 may be provided.

[0301] In this example, the functional blocks of the characteristic parts of this 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 part described below may be omitted.

[0302] The control unit 110 controls the entire base station 10. The control unit 110 can be composed of a controller, control circuit, etc., as described based on common understanding in the technical field related to this disclosure.

[0303] The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may also control transmission and reception, measurement, etc., using the transmitting / receiving unit 120, transmitting / receiving antenna 130, and transmission path interface 140. The control unit 110 may generate data to be transmitted as signals, control information, sequences, etc., and transfer them to the transmitting / receiving unit 120. The control unit 110 may also perform call processing of communication channels (setting, releasing, etc.), status management of the base station 10, management of wireless resources, etc.

[0304] The transmitting / receiving 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 transmitting / receiving unit 120 can be composed of a transmitter / receiver, RF circuit, baseband circuit, filter, phase shifter, measurement circuit, transmitting / receiving circuit, etc., as described based on common understanding in the art relating to this disclosure.

[0305] The transmitting / receiving unit 120 may be configured as an integrated transmitting / receiving unit, or it may be composed of a transmitting unit and a receiving unit. The transmitting unit may consist of a transmitting processing unit 1211 and an RF unit 122. The receiving unit may consist of a receiving processing unit 1212, an RF unit 122 and a measuring unit 123.

[0306] The transmitting and receiving antenna 130 can be composed of an antenna described based on common understanding in the art relating to this disclosure, such as an array antenna.

[0307] The transmitting / receiving unit 120 may transmit the downlink channel, synchronization signal, downlink reference signal, etc. The transmitting / receiving unit 120 may also receive the uplink channel, uplink reference signal, etc.

[0308] The transmitting / receiving unit 120 may use digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like to form at least one of the transmitting beam and the receiving beam.

[0309] The transmitting / receiving unit 120 (transmission processing unit 1211) may perform processing on data and control information acquired from the control unit 110, for example, at the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer (e.g., RLC retransmission control), and the Medium Access Control (MAC) layer (e.g., HARQ retransmission control), to generate a bit sequence to be transmitted.

[0310] The transmitting / receiving unit 120 (transmission processing unit 1211) may perform transmission processing on the bit sequence to be transmitted, 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, and output a baseband signal.

[0311] The transmitting / receiving unit 120 (RF unit 122) may perform modulation, filtering, amplification, etc., of the baseband signal to the radio frequency band and transmit the signal in the radio frequency band via the transmitting / receiving antenna 130.

[0312] On the other hand, the transmitting / receiving unit 120 (RF unit 122) may perform amplification, filtering, demodulation to a baseband signal, etc., on the radio frequency band signal received by the transmitting / receiving antenna 130.

[0313] The transmitting / receiving unit 120 (receiving 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 (may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal to acquire user data, etc.

[0314] The transmitting / receiving unit 120 (measurement unit 123) may perform measurements related to 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 also measure received power (e.g., Reference Signal Received Power (RSRP)), reception 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.

[0315] The transmission path interface 140 may send and receive signals (backhaul signaling) with 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.

[0316] In this disclosure, the transmitting and receiving units of the base station 10 may consist of at least one of a transmitting / receiving unit 120, a transmitting / receiving antenna 130, and a transmission path interface 140.

[0317] The base station 10 may be separated into three elements: a Radio Unit (RU), a Distributed Unit (DU), and a Central Unit (CU). For example, the RU may implement RF processing (digital beamforming, digital-to-analog conversion, analog beamforming, etc.) and lower-level physical layer functions (precoding, IFFT, FFT, etc.). The DU may implement higher-level physical layer functions (coding to resource element mapping, etc.), MAC layer functions, and RLC layer functions. The CU may implement PDCP layer, Service Data Adaptation Protocol (SDAP) layer, and RRC layer functions.

[0318] In this disclosure, base station 10 may include a single device that implements all the functions of RU, DU, and CU, or it may include multiple devices that each implement some of the functions of RU, DU, and CU and are connected to each other. In this disclosure, base station 10 may be interpreted as RU / DU / CU.

[0319] The transmitting / receiving unit 120 may transmit at least one of a first downlink signal on the first frequency of the first cell and a second downlink signal on the second frequency of the second cell. The control unit 110 may control the handover from the first cell to the second cell and control the transmission and reception of data on the third frequency of the second cell based on the first downlink signal and the second downlink signal.

[0320] (User Terminal) Figure 20 shows an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transmitting / receiving unit 220, and a transmitting / receiving antenna 230. Note that one or more of the control unit 210, the transmitting / receiving unit 220, and the transmitting / receiving antenna 230 may be provided.

[0321] In this example, the functional blocks of the characteristic parts of this 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 part described below may be omitted.

[0322] The control unit 210 controls the entire user terminal 20. The control unit 210 can be composed of a controller, control circuit, etc., as described based on common understanding in the technical field related to this disclosure.

[0323] The control unit 210 may control signal generation, mapping, etc. The control unit 210 may also control transmission and reception, measurement, etc., using the transmitting / receiving unit 220 and the transmitting / receiving antenna 230. The control unit 210 may generate data to be transmitted as signals, control information, sequences, etc., and transfer them to the transmitting / receiving unit 220.

[0324] The transmitting / receiving 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 transmitting / receiving unit 220 can be composed of a transmitter / receiver, RF circuit, baseband circuit, filter, phase shifter, measurement circuit, transmitting / receiving circuit, etc., as described based on common understanding in the art relating to this disclosure.

[0325] The transmitting / receiving unit 220 may be configured as an integrated transmitting / receiving unit, or it may be composed of a transmitting unit and a receiving unit. The transmitting unit may consist of a transmitting processing unit 2211 and an RF unit 222. The receiving unit may consist of a receiving processing unit 2212, an RF unit 222 and a measuring unit 223.

[0326] The transmitting and receiving antenna 230 can be composed of an antenna described based on common understanding in the art relating to this disclosure, such as an array antenna.

[0327] The transmitting / receiving unit 220 may receive the downlink channel, synchronization signal, downlink reference signal, etc. The transmitting / receiving unit 220 may also transmit the uplink channel, uplink reference signal, etc.

[0328] The transmitting / receiving unit 220 may use digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like to form at least one of the transmitting beam and the receiving beam.

[0329] The transmitting / receiving 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 and control information acquired from the control unit 210 to generate a bit sequence to be transmitted.

[0330] The transmitting / receiving unit 220 (transmission processing unit 2211) may perform transmission processing on the bit sequence to be transmitted, 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, and output a baseband signal.

[0331] Whether or not to apply DFT processing may be based on the transform precoding settings. The transmitting / receiving unit 220 (transmission processing unit 2211) may perform DFT processing as part of the transmission process to transmit a channel (for example, PUSCH) using a DFT-s-OFDM waveform if transform precoding is enabled for that channel, or it may not perform DFT processing as part of the transmission process if transform precoding is not enabled for that channel.

[0332] The transmitting / receiving unit 220 (RF unit 222) may perform modulation, filtering, amplification, etc., of the baseband signal to the radio frequency band and transmit the signal in the radio frequency band via the transmitting / receiving antenna 230.

[0333] On the other hand, the transmitting / receiving unit 220 (RF unit 222) may perform amplification, filtering, demodulation to a baseband signal, etc., on the radio frequency band signal received by the transmitting / receiving antenna 230.

[0334] The transmitting / receiving unit 220 (receiving processing unit 2212) may apply reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal to acquire user data, etc.

[0335] The transmitting / receiving unit 220 (measuring unit 223) may perform measurements related to the received signal. For example, the measuring unit 223 may perform RRM measurement, CSI measurement, etc., based on the received signal. The measuring unit 223 may also 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.

[0336] The measurement unit 223 may derive channel measurements for CSI calculation based on channel measurement resources. 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. Interference measurement resources may be at least one of the following: NZP CSI-RS resources for interference measurement, CSI-Interference Measurement (IM) resources, etc. CSI-IM may also be called CSI-Interference Management (IM), and may be interpreted interchangeably with Zero Power (ZP) CSI-RS. In this disclosure, CSI-RS, NZP CSI-RS, ZP CSI-RS, CSI-IM, CSI-SSB, etc., may be interpreted interchangeably.

[0337] In this disclosure, the transmitting unit and receiving unit of the user terminal 20 may be composed of at least one of a transmitting / receiving unit 220 and a transmitting / receiving antenna 230.

[0338] The transmitting / receiving unit 220 may receive a first downlink signal on a first frequency of the first cell and a second downlink signal on a second frequency of the second cell. The control unit 210 may control the handover from the first cell to the second cell and control the transmission and reception of data on a third frequency of the second cell based on the first and second downlink signals. The first frequency may be, for example, the frequency [band] of the first or third carrier. The second frequency may be, for example, the frequency [band] of the first or third carrier. The third frequency may be, for example, the frequency [band] of the third carrier. The first downlink signal may be, for example, the second signal and any of the following: mobility RS, DL-RS, P-RS, SSB, and mobility CSI-RS. The second downlink signal may be, for example, the second signal, mobility RS, DL-RS, P-RS, SSB, or mobility CSI-RS.

[0339] The second frequency may be different from the third frequency. Here, the second frequency may be, for example, the frequency [band] of the first carrier.

[0340] The second frequency may be equal to the first frequency.

[0341] The control unit 210 may control the transmission of the physical random access channel on the fourth frequency based on the second downlink signal. The fourth frequency may be, for example, the frequency [band] of the first, second, or third carrier [of the second cell].

[0342] (Hardware Configuration) The block diagram used in the description of the above embodiment shows functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may also be realized by combining the above one device or the above multiple devices with software.

[0343] Here, functions include, but are not limited to, judgment, decision, determination, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission may be called a transmitting unit or transmitter. In all cases, as mentioned above, the method of implementation is not particularly limited.

[0344] For example, a base station, user terminal, etc. in one embodiment of the present disclosure may function as a computer that processes the wireless communication method of the present disclosure. Figure 21 is a diagram showing an example of the hardware configuration of a base station and user terminal according to one embodiment. The base station 10 and user terminal 20 described above may be physically configured as a computer device including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, etc.

[0345] In this disclosure, terms such as apparatus, circuit, device, section, and unit are interchangeable. The hardware configuration of the base station 10 and the user terminal 20 may include one or more of the devices shown in the figure, or it may be configured without some of the devices.

[0346] For example, although only one processor 1001 is shown in the diagram, there may be multiple processors. Furthermore, the processing may be performed by one processor, or it may be performed by two or more processors simultaneously, sequentially, or by other means. Note that the processor 1001 may be implemented using one or more chips.

[0347] Each function in the base station 10 and the user terminal 20 is realized, for example, by loading predetermined software (programs) onto hardware such as the processor 1001 and memory 1002, which allows the processor 1001 to perform calculations and control communication via the communication device 1004, or control at least one of reading and writing data in the memory 1002 and storage 1003.

[0348] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may be composed of a central processing unit (CPU) that includes interfaces with peripheral devices, control devices, arithmetic units, registers, etc. For example, at least a part of the control unit 110 (210) and the transmitting / receiving unit 120 (220) described above may be implemented by the processor 1001.

[0349] Furthermore, the processor 1001 reads programs (program code), 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 accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. 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 other functional blocks may be implemented similarly.

[0350] The memory 1002 is a computer-readable recording medium and may consist of at least one of the following: Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically EPROM (EEPROM), Random Access Memory (RAM), or other suitable storage medium. The memory 1002 may also be called a register, cache, or main memory. The memory 1002 can store executable programs (program code), software modules, etc., for carrying out a wireless communication method according to one embodiment of the present disclosure.

[0351] The storage 1003 is a computer-readable recording medium and may consist of at least one of the following: a flexible disk, a floppy disk, a magneto-optical disk (e.g., a Compact Disk (Compact Disc ROM (CD-ROM)), a Digital Use Disk, a Blu-ray (registered trademark) disk), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, stick, key drive), a magnetic stripe, a database, a server, or other suitable storage medium. The storage 1003 may also be called an auxiliary storage device.

[0352] The communication device 1004 is hardware (transmitting / receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, duplexer, filter, frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the above-mentioned transmitting / receiving unit 120 (220), transmitting / receiving antenna 130 (230), etc., may be implemented by the communication device 1004. The transmitting / receiving unit 120 (220) may be implemented with physically or logically separated transmitting unit 120a (220a) and receiving unit 120b (220b).

[0353] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, light-emitting diode (LED) lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0354] Furthermore, each device, such as the processor 1001 and memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0355] 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), and a field programmable gate array (FPGA), and some or all of each functional block may be implemented using such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0356] Furthermore, devices included in the core network 30 (for example, network nodes that provide NF) may also be implemented using the functional block / hardware configuration described above.

[0357] (Variations) Terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, channel, symbol and signal (signal or signaling) may be used interchangeably. Also, a signal may be a message. A reference signal may be abbreviated as RS and may be called a pilot, pilot signal, etc., depending on the applicable standard. Also, a component carrier (CC) may be called a cell, frequency carrier, carrier frequency, etc.

[0358] A wireless frame may consist of one or more periods (frames) in the time domain. Each of these periods (frames) constituting a wireless frame may be called a subframe. Furthermore, a subframe may consist 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.

[0359] Here, the neurology may be communication parameters applied to at least one of the transmission and reception of a signal or channel. The neurology may be, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain.

[0360] A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols). Alternatively, a slot may be a time unit based on neurology.

[0361] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. Minislots may also be called subslots. Minislots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called a PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using minislots may be called a PDSCH (PUSCH) mapping type B.

[0362] Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Wireless frames, subframes, slots, minislots, and symbols may each be referred to by different names. Furthermore, the units of time such as frames, subframes, slots, minislots, and symbols in this disclosure may be interpreted as interchangeable.

[0363] For example, one subframe may be called a TTI, multiple consecutive subframes may be called a TTI, and one slot or one mini-slot may be called a TTI. In other words, at least one of a subframe and a TTI may be a subframe in existing LTE (1 ms), a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing a TTI may be called a slot, mini-slot, etc., instead of a subframe.

[0364] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, the base station schedules each user terminal to allocate wireless resources (such as the frequency bandwidth and transmission power available to each user terminal) in TTI units. However, the definition of TTI is not limited to this.

[0365] TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the actual time interval (e.g., number of symbols) in which the transport block, code block, code word, etc. are mapped may be shorter than the TTI.

[0366] Furthermore, if one slot or one mini-slot is referred to as a TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit for scheduling. In addition, the number of slots (number of mini-slots) that constitute this minimum time unit for scheduling may be controlled.

[0367] A TTI with a time length of 1 ms may be called a normal TTI, long TTI, normal subframe, long subframe, slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, mini slot, sub slot, slot, etc.

[0368] Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more.

[0369] A Resource Block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology.

[0370] Furthermore, an RB may contain one or more symbols in the time domain and may have the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks.

[0371] One or more RBs may also be called Physical RBs (PRBs), Sub-Carrier Groups (SCGs), Resource Element Groups (REGs), PRB pairs, RB pairs, etc.

[0372] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area comprising one subcarrier and one symbol.

[0373] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a given neurology in a given carrier. These common RBs may be identified by an index of the RBs relative to a common reference point of the carrier. The PRBs may be defined and numbered within a given BWP.

[0374] A BWP may include UL BWP (BWP for UL) and DL BWP (BWP for DL). One or more BWPs may be configured within a single carrier for a UE.

[0375] At least one of the configured BWPs may be active, and the UE does not need to assume that it will transmit or receive a predetermined signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0376] The structures of wireless frames, subframes, slots, minislots, and symbols described above are merely examples. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless 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, and the number of symbols, symbol length, and cyclic prefix (CP) length within the TTI can be varied in various ways.

[0377] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or corresponding other information. For example, wireless resources may be indicated by a predetermined index.

[0378] The names used for parameters and other elements in this disclosure are not restrictive in any way. Furthermore, mathematical formulas and other elements using these parameters may differ from those expressly disclosed in this disclosure. Various channels (PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0379] The information, signals, etc. described in this disclosure may be represented using any of the various different techniques. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0380] Furthermore, information, signals, etc., can be output from upper layers to lower layers and from lower layers to upper layers, or to at least one of the two. Information, signals, etc., may also be input and output via multiple network nodes.

[0381] Input and output information and signals may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information and signals may be overwritten, updated, or appended to. Output information and signals may be deleted. Input information and signals may be transmitted to other devices.

[0382] Any information described in this disclosure (e.g., variables, constants, parameters) may be communicated from any first device (e.g., UE / base station) to any second device (e.g., base station / UE) that indicates / specifies (or relates to) the value of such any information, even if not specifically stated in the embodiments described above.

[0383] Information notification is not limited to the embodiments described herein and may be carried out by other means. For example, information notification in this disclosure may be carried out by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB)), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0384] Physical layer signaling may also be called Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signals), L1 control information (L1 control signals), etc. RRC signaling may also be called RRC messages, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc. MAC signaling may also be communicated using, for example, MAC Control Elements (CEs).

[0385] Furthermore, notification of the specified information (for example, notification that "X is the case") is not limited to explicit notification, but may also be made implicitly (for example, by not notifying the specified information or by notifying other information).

[0386] The determination may be made by a value represented by one bit (0 or 1), by a boolean value represented as true or false, or by a numerical comparison (for example, a comparison with a predetermined value).

[0387] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0388] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or Digital Subscriber Line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0389] The terms “system” and “network” as used in this disclosure may be used interchangeably. “Network” may also mean the equipment included in the network (e.g., base stations).

[0390] 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,” and “receiving entity” may be used interchangeably.

[0391] In this disclosure, "antenna port" may be interpreted interchangeably with "antenna port for any signal / channel" (e.g., a Demodulation Reference Signal (DMRS) port). In this disclosure, "resource" may be interpreted interchangeably with "resource for any signal / channel" (e.g., a reference signal resource, an SRS resource, etc.). Resources may include time / frequency / code / spatial / power resources. Furthermore, a spatial domain transmit filter may include at least one of a spatial domain transmit filter and a spatial domain receive filter.

[0392] The above group may include, for example, at least one of the following: 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, or a panel group.

[0393] Furthermore, in this disclosure, terms such as beam, SRS Resource Indicator (SRI), CORESET, CORESET pool, PDSCH, PUSCH, Codeword (CW), Transport Block (TB), and RS may be interpreted interchangeably.

[0394] Furthermore, in this disclosure, 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 interpreted interchangeably.

[0395] Furthermore, in this disclosure, terms such as "QCL," "QCL assumption," "QCL relationship," "QCL type information," "QCL property / properties," "specific QCL type (e.g., Type A, Type D) properties," and "specific QCL type (e.g., Type A, Type D)" may be interpreted interchangeably.

[0396] In this disclosure, terms such as index, identifier (ID), indicator, indication, and resource ID may be interpreted interchangeably. In this disclosure, terms such as sequence, list, set, group, cluster, subset may be interpreted interchangeably.

[0397] Furthermore, the spatial relationship information Identifier (ID) (TCI state ID) and spatial relationship information (TCI state) may be interpreted as mutually exclusive. "Spatial relationship information (TCI state)" may be interpreted as mutually exclusive as "a set of spatial relationship information (TCI state)," "one or more pieces of spatial relationship information," etc. TCI state and TCI may be interpreted as mutually exclusive. Spatial relationship information and spatial relationship may be interpreted as mutually exclusive.

[0398] In this disclosure, terms such as “Base Station (BS),” “wireless 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,” and “component carrier” may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0399] A base station may house one or more (e.g., three) cells. If a base station houses multiple cells, the entire coverage area of ​​the base station may be divided into several smaller areas, each of which may also be provided with communication services 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 ​​at least one of the base station and / or base station subsystems that provide communication services in that coverage.

[0400] In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform a control / operation based on said information.

[0401] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0402] A mobile station may also be called 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 appropriate term.

[0403] 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. At least one of the base station and the mobile station may also be a device mounted on a moving object, the moving object itself, etc.

[0404] The term "mobile object" refers to any movable object, regardless of its speed, and naturally includes cases where the mobile object is stationary. Examples of such mobile objects include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones, multicopters, quadcopters, balloons, and items carried on them. Furthermore, such mobile objects may be autonomously driven objects operating based on operational commands.

[0405] The mobile entity may be a vehicle (e.g., a car, an airplane), an unmanned mobile entity (e.g., a drone, an autonomous vehicle), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does 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.

[0406] Figure 22 shows an example of a vehicle according to one 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, an axle 48, an electronic control unit 49, various sensors (including a current sensor 50, a rotation speed sensor 51, a pneumatic 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.

[0407] The drive unit 41 consists of, for example, at least one of an engine, a motor, or an engine-motor hybrid. 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 the user.

[0408] The electronic control unit 49 consists of a microprocessor 61, memory (ROM, RAM) 62, and communication ports (e.g., input / output (IO) ports) 63. Signals from various sensors 50-58 installed in the vehicle are input to the electronic control unit 49. The electronic control unit 49 may also be called an Electronic Control Unit (ECU).

[0409] Signals from various sensors 50-58 include current signals from current sensor 50 for sensing motor current, rotational speed signals of front wheels 46 / rear wheels 47 acquired by rotational speed sensor 51, air pressure signals of front wheels 46 / rear wheels 47 acquired by air pressure sensor 52, vehicle speed signals acquired by vehicle speed sensor 53, acceleration signals acquired by acceleration sensor 54, accelerator pedal depression amount signals acquired by accelerator pedal sensor 55, brake pedal depression amount signals acquired by brake pedal sensor 56, operation signals of shift lever 45 acquired by shift lever sensor 57, and detection signals acquired by object detection sensor 58 for detecting obstacles, vehicles, pedestrians, etc.

[0410] The information service unit 59 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including a car navigation system, audio system, speakers, display, television, and radio, and one or more ECUs that control these devices. The information service unit 59 uses information acquired from external devices via a communication module 60 or the like to provide various types of information / services (for example, multimedia information / multimedia services) to the occupants of the vehicle 40.

[0411] The information service unit 59 may include input devices that accept input from the outside (e.g., keyboard, mouse, microphone, switch, button, sensor, touch panel, etc.) or output devices that perform output to the outside (e.g., display, speaker, LED lamp, touch panel, etc.).

[0412] The driver assistance system unit 64 consists of various devices that provide functions to prevent accidents or reduce the driver's workload, 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 Unit (IMU), Inertial Navigation System (INS)), artificial intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 64 also transmits and receives various information via the communication module 60 to realize driver assistance functions or autonomous driving functions.

[0413] 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 sends and receives data (information) via the communication port 63 to 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, axle 48, the microprocessor 61 and memory (ROM, RAM) 62 in the electronic control unit 49, and various sensors 50-58 provided in the vehicle 40.

[0414] 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 external devices. For example, it can send and receive various types of information to and from external devices 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. Alternatively, the communication module 60 may be, for example, at least one of the base station 10 and the user terminal 20 (it may function as at least one of the base station 10 and the user terminal 20).

[0415] The communication module 60 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 50-58 input to the electronic control unit 49, information obtained based on said signals, and information based on input from an external source (user) obtained via the information service unit 59. The electronic control unit 49, the various sensors 50-58, the information service unit 59, etc., may also be called input units that accept input. For example, the PUSCH transmitted by the communication module 60 may include the information based on the above input.

[0416] The communication module 60 receives various information (traffic information, signal information, inter-vehicle information, etc.) transmitted from an external device and displays it on the information service unit 59 installed in the vehicle. The information service unit 59 may also be called an output unit, which outputs information (for example, it outputs information to devices such as displays and speakers based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 60).

[0417] 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, axle 48, various sensors 50-58, etc., which are provided in the vehicle 40.

[0418] Furthermore, the term "base station" in this disclosure may be interpreted as "user terminal." For example, the various aspects / embodiments of this 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), Vehicle-to-Everything (V2X)). In this case, the user terminal 20 may have the functions of the base station 10 described above. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "sidelink"). For example, uplink channel, downlink channel, etc., may be interpreted as sidelink channel.

[0419] Similarly, the term "user terminal" in this disclosure may be replaced with "base station." In this case, the base station 10 may be configured to have the same functions as the user terminal 20 described above.

[0420] In this disclosure, operations performed by a base station may, in some cases, be performed by its upper node. In a network including one or more network nodes having base stations, it is clear that various operations performed for communication with terminals may be performed by the base station, one or more network nodes other than the base station (for example, a Mobility Management Entity (MME), a Serving Gateway (S-GW), etc., but not limited to these), or a combination thereof.

[0421] Each aspect / embodiment described in this disclosure may be used individually, in combination, or switched between as needed during execution. Furthermore, the processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described in this disclosure may be rearranged in order, provided they are consistent. For example, the methods described in this disclosure present various step elements using exemplary order and are not limited to the specific order presented.

[0422] Each aspect / embodiment described in this disclosure is 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 (where x is, for example, an integer or decimal)), 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®), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, systems utilizing Ultra-WideBand (UWB), Bluetooth®, or other appropriate wireless communication methods, and next-generation systems extended, modified, created, or defined based thereon may also be applied. Furthermore, multiple systems may be applied in combination (for example, a combination of LTE or LTE-A and 5G).

[0423] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0424] Any reference to elements using the designations “first,” “second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, the references to the first and second elements do not imply that only two elements may be employed or that the first element must precede the second element in any way.

[0425] The term “determining” as used in this disclosure may encompass a wide variety of actions. For example, “determining” may be considered to mean judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in tables, databases, or other data structures), ascertaining, etc.

[0426] Furthermore, "judgment (decision)" may be considered as "judging (deciding)" things like receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory).

[0427] Furthermore, “judgment (decision)” may be considered as “judgment (decision)” of resolving, selecting, choosing, establishing, comparing, etc. In other words, “judgment (decision)” may be considered as “judgment (decision)” of some action. In this disclosure, “judgment (decision)” may be interpreted as mutually interchangeable with the actions described above.

[0428] Furthermore, in this disclosure, “determine / determining” may be interpreted as “assume / assuming,” “expect / expecting,” or “consider / considering.” In addition, in this disclosure, “not expecting to do…” may be interpreted as “expecting not to do….”

[0429] In this disclosure, "expect" may be rephrased as "be expected." For example, "expect(s) ..." (where "..." may be expressed as a that clause, an infinitive, etc.) may be rephrased as "be expected ..." or "do (the verb without "to" if "..." is an infinitive)." Similarly, "does not expect ..." may be rephrased as "be not expected ..." or "do not (the verb without "to" if "..." is an infinitive)." Furthermore, "An apparatus A is not expected ..." may be rephrased as "An apparatus B other than apparatus A does not expect ... from apparatus A" (for example, if apparatus A is a UE, apparatus B may be a base station).

[0430] The term "maximum transmit power" as used in this disclosure may mean the maximum transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0431] As used in this disclosure, the terms “connected,” “coupled,” and any variations thereof mean any direct or indirect connection or coupling between two or more elements, and may include one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be replaced with “access.”

[0432] In this disclosure, when two elements are connected, they can be considered to be "connected" or "coupled" to each other using one or more wires, cables, printed electrical connections, etc., and, in some non-exclusive and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0433] In this 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 "combine" may be interpreted similarly to "different."

[0434] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0435] In this disclosure, if articles are added by translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0436] In this disclosure, "less than or equal to," "less than," "greater than or equal to," "more than," and "equal to" may be interpreted interchangeably. In addition, in this disclosure, words meaning "good," "bad," "big," "small," "high," "low," "early," "slow," "wide," and "narrow" may be interpreted interchangeably, not limited to the positive, comparative, and superlative degrees. In addition, in this disclosure, words meaning "good," "bad," "big," "small," "high," "low," "early," "slow," "wide," and "narrow" may be interpreted interchangeably, not limited to the positive, comparative, and superlative degrees, by adding "i-th" (where i is any integer) to the expression (for example, "highest" may be interpreted interchangeably with "i-th highest").

[0437] In this disclosure, "of," "for," "regarding," "related to," and "associated with" may be interpreted as being interchangeable.

[0438] In this disclosure, phrases 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. Furthermore, A, B, etc., may be replaced with appropriate expressions such as nouns, gerunds, or regular sentences depending on the context. The time difference between A and B may be approximately zero (immediately after or immediately before). Additionally, a time offset may be applied to the time when A occurs. For example, "A" may be interpreted as "before / after the time offset when A occurs". The time offset (e.g., one or more symbols / slots) may be predetermined or determined by the UE based on notified information.

[0439] In this disclosure, timing, time, duration, time instance, any unit of time (e.g., slot, subslot, symbol, subframe), period, occasion, resource, etc., may be interpreted interchangeably.

[0440] Although the invention described herein has been explained in detail above, it will be clear to those skilled in the art that the invention described herein is not limited to the embodiments described herein. The descriptions herein are illustrative and not intended to be restrictive in any way to the invention described herein.

Claims

1. A terminal having: a receiving unit that receives a first downlink signal on a first frequency of a first cell and a second downlink signal on a second frequency of a second cell; and a control unit that controls the handover from the first cell to the second cell and controls the transmission and reception of data on a third frequency of the second cell based on the first downlink signal and the second downlink signal.

2. The terminal according to claim 1, wherein the second frequency is different from the third frequency.

3. The terminal according to claim 1, wherein the second frequency is equal to the first frequency.

4. The terminal according to claim 1, wherein the control unit controls the transmission of a physical random access channel on a fourth frequency based on the second downlink signal.

5. A wireless communication method for a terminal, comprising the steps of: receiving a first downlink signal on a first frequency of a first cell and a second downlink signal on a second frequency of a second cell; controlling a handover from the first cell to the second cell based on the first downlink signal and the second downlink signal; and controlling the transmission and reception of data on a third frequency of the second cell.

6. A base station having: a transmitting unit that transmits at least one of a first downlink signal on a first frequency of a first cell and a second downlink signal on a second frequency of a second cell; and a control unit that controls a handover from the first cell to the second cell and controls the transmission and reception of data on a third frequency of the second cell based on the first downlink signal and the second downlink signal.

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