Terminal, wireless communication method, and base station

Abstract

A terminal according to one aspect of the present disclosure comprises: a reception unit that monitors a plurality of frequencies, detects a first carrier common to a plurality of terminals, and receives a synchronization signal transmitted on the first carrier; and a control unit that, on the basis of the synchronization signal, controls at least one of reception of system information corresponding to the first carrier and search for another first carrier. One aspect of the present disclosure can realize advanced services that surpass the 5G NR.

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, in order to realize such services, the introduction of initial access to one or more carriers is being considered. However, the details of such initial access have not been sufficiently considered. 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 monitors multiple frequencies, detects a first carrier common to multiple terminals, and receives a synchronization signal transmitted on the first carrier, and a control unit that controls, based on the synchronization signal, receiving system information corresponding to the first carrier, searching for another first carrier, and controlling at least one of the two.

[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 a cellular system. Figure 2B shows an overview of a cell-free system. Figure 3A shows an example overview of hypothetical configuration 1 of cell-free. Figure 3B shows an example overview of hypothetical configuration 2 of cell-free. Figure 3C shows another example overview of hypothetical configuration 2 of cell-free. Figure 4 shows an example of carrier design in a future wireless communication system. Figure 5 shows an example of operation up to initial access according to the first embodiment. Figure 6 shows an example of operation up to initial access according to the second embodiment. Figure 7 shows an example of schematic configuration of a wireless communication system according to one embodiment. Figure 8 shows an example of base station configuration according to one embodiment. Figure 9 shows an example of user terminal configuration according to one embodiment. Figure 10 shows an example of hardware configuration of base station and user terminal according to one embodiment. Figure 11 shows an example of 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] (Carrier Design in Future Wireless Communication Systems) In future wireless communication systems (e.g., after Rel. 21, 6G systems), in order to solve social issues after the 2030s, the realization of advanced services beyond the 5G NR system as exemplified below is expected. ・Expandable Network (NW). ・Easy-to-operate NW. ・Sustainable / Resilient NW. ・Performance (e.g., throughput / capacity) improvement at lower bit costs. ・Significant reduction in the cost / complexity / power consumption of the cellular NW. ・Increased revenue / new value creation by the cellular NW.

[0044] Regarding the expandable NW, it is desirable that the basic 6G system design be applicable not only to the use cases in the 6G system but also to potential new use cases in the future. This is because it is beneficial and practical for functions expected to be released in the future.

[0045] Regarding the easy-to-operate NW, it is desirable to avoid specifying multiple options for the same purpose.

[0046] Regarding the sustainable / resilient NW, a significant reduction in cost / energy consumption is desired for both the NW side and the terminal (user terminal, User Equipment (UE)) side. Also, an improvement in fault tolerance and early recovery for all events (e.g., operation errors / large traffic / disasters, etc.) is desired.

[0047] Hereinafter, referring to FIG. 4, an example of carrier design in a future wireless communication system will be described.

[0048] The UE may monitor a plurality of frequencies (e.g., which may be called monitoring frequencies / synchronization raster) to detect the first carrier (e.g., which may be called a perch carrier).

[0049] When the first carrier is detected, the UE may execute a synchronization operation (which may be called the first synchronization) and receive / acquire information (e.g., system information).

[0050] The UE may perform initial access / random access on a second carrier (which may be called an anchor carrier, for example) based on the received / acquired information (e.g., system information) and establish an RRC connection with the NW. At least a portion of the initial access / random access may be performed on the first carrier.

[0051] 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.

[0052] 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.

[0053] Figure 4 shows the low-frequency band (coverage band) and the 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.

[0054] 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).

[0055] 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.

[0056] 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.

[0057] For 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. In 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.

[0058] 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.

[0059] <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.

[0060] 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).

[0061] 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.

[0062] In this disclosure, the number of monitoring frequency / synchronous rasters may be more limited (e.g., smaller) than the number of monitoring frequency / synchronous rasters in existing NRs. In other words, the frequency spacing of the monitoring frequency / synchronous rasters may be wider than in existing NRs.

[0063] For example, the location of a synchronization raster may be defined based on its relationship to information relating 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 synchronization rasters based on that assumption.

[0064] 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.

[0065] 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 at (only) the specific frequency positions in which it is defined for each of the bandwidths it supports. Alternatively, a UE may assume that a GSCN or synchronous raster is defined only at (only) specific frequency positions in a given bandwidth, and may monitor or search for a GSCN or synchronous raster based on that assumption.

[0066] 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.

[0067] The monitoring frequency resources detected by the UE may correspond to potential perch carriers (first carriers).

[0068] <Perch Carrier> The first carrier may be a carrier common to multiple UEs.

[0069] The first carrier could be a common carrier regardless of the use case / service / device type, for example.

[0070] 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.

[0071] The first carrier (and the signal transmitted in it) may always be kept in the ON state.

[0072] 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.

[0073] The first carrier may have a frequency lower than a specific value (for example, 800 MHz).

[0074] The first carrier may correspond to a single (base station) beam.

[0075] 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.

[0076] The first carrier may, for example, be included in a coverage band.

[0077] 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.

[0078] <Anchor Carrier> The second carrier may be a carrier / frequency used for network connection / control.

[0079] 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.

[0080] 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.

[0081] 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)."

[0082] By using a second carrier to perform LP-WUS / WUR related operations, it is possible to reduce network energy consumption and user energy consumption.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] The second carrier may, for example, be included in a coverage band.

[0087] 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.

[0088] <Data Carrier> The third carrier may be a carrier used for transmitting / receiving data.

[0089] The third carrier could be an individual carrier for each UE, for multiple UEs (UE groups), for each use case, or for each service.

[0090] 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.

[0091] 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.

[0092] The third career may include the first career.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] Furthermore, the carrier design described above may be applied to a cell-free configuration as appropriate. For example, the first carrier may correspond to a first cell (e.g., a supercell) or to a second cell (e.g., an area). Also, for example, the second carrier may correspond to a first cell (e.g., a supercell) or to a second cell (e.g., an area). Also, for example, the third carrier may correspond to a second cell (e.g., an area).

[0098] (Analysis) In existing wireless communication systems (e.g., 5G NR), the UE (User Entrant) camps on / initial access to one of the available carriers.

[0099] When a UE (User Environment) uses multiple carriers for communication, control procedures related to carrier aggregation (CA) / dual connectivity (DC) are required after RRC (Range-Relational Control) connection. This leads to increased signaling overhead and base station power consumption.

[0100] Furthermore, in order to enable initial access / CA / DC across multiple carriers, each carrier needs to transmit basic signals such as synchronization signals (e.g., SSB), which also leads to an increase in base station power consumption.

[0101] Furthermore, in existing wireless communication systems, the frequency selection operation of the UE during cell selection depends on the UE implementation, and there is a problem that the carrier / cell targeted for camping / initial access may be biased towards a particular carrier / cell. In particular, while load balancing handover (load balancing handover) is feasible when cell reselection / RRC connection is made, detailed control of cell selection in idle / inactive mode cannot be achieved, and handover during RRC connection leads to increased signaling overhead.

[0102] Therefore, the introduction of initial access to one or more carriers is being considered for future wireless communication systems. However, the details of this have not been sufficiently examined.

[0103] More specifically, the specifications and UE operations regarding frequency / band / raster related to the search for synchronization signals have not been adequately considered. Furthermore, the specifications and UE operations regarding the reception of synchronization signals when performing initial access to multiple carriers (simultaneously) have not been adequately considered.

[0104] If these considerations are insufficient, it may not be possible to reduce signaling overhead and save energy at base stations, potentially preventing the implementation of advanced services beyond 5G NR.

[0105] Therefore, the inventors have conceived a way to solve these problems. According to one embodiment of this disclosure, it is possible to access cells with fewer steps / lower latency / lower power consumption compared to existing systems, and to access cells that meet the services / requirements required by the UE with appropriate load balancing in mind. Furthermore, according to one embodiment of this disclosure, it is possible to realize communication using multiple carriers / bands over a wide range and / or the bandwidth required for communication.

[0106] 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.

[0107] In this disclosure, the cell configuration may be the cell-free configuration described above, but is not limited thereto.

[0108] (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.

[0109] 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".

[0110] 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.

[0111] 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.

[0112] 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).

[0113] 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).

[0114] In this disclosure, physical layer signaling may be, for example, layer (L)1 / L2 signaling, downlink control information (DCI), uplink control information (UCI), etc.

[0115] In this disclosure, basic signals, synchronization signals (PSS / SSS), broadcast signals, synchronization signals / broadcast signals, SSB, SS / PBCH blocks, system information, system information blocks (SIB, SIB1, SIBx (where x is any number)), master information blocks (MIB), paging, etc. may be interpreted as interchangeable.

[0116] In this disclosure, signals, channels, information, etc., may be interpreted interchangeably.

[0117] In this disclosure, carrier, frequency carrier, component carrier, frequency, band, frequency band, raster, synchronous raster, cell, channel, etc. may be interpreted interchangeably.

[0118] In this disclosure, "perch" and "1" may be interpreted as interchangeable. In this disclosure, "anchor" and "2" may be interpreted as interchangeable. In this disclosure, "data" and "3" may be interpreted as interchangeable.

[0119] In this disclosure, search, monitor, receive, etc. may be interpreted interchangeably.

[0120] (Wireless communication method) <First embodiment> The first embodiment relates to the reception regulations and operation of synchronization signals / broadcast signals.

[0121] The first embodiment may apply to at least one of the following cases: a case of initial access to a single carrier, and a case of initial access utilizing a single carrier (e.g., an anchor carrier) based on information in a single perch carrier. These cases may be referred to as single-carrier-based initial access.

[0122] Furthermore, the first embodiment may be applied to at least one of the following cases: a case in which initial access is performed to multiple carriers, and a case in which initial access is performed using multiple carriers (e.g., multiple anchor carriers) based on information in one perch carrier. These cases may be called multi-carrier-based initial access.

[0123] The UE may, in the cell selection / cell search procedure, search for synchronization signals / broadcast signals [only] in a specific band / raster.

[0124] The particular band / raster may be a more limited (e.g., smaller) band / raster than, for example, the number of bands (e.g., monitoring frequencies) / rasters (e.g., synchronization rasters) in an existing system (e.g., 5G NR). In other words, the frequency spacing of the particular band / raster may be wider than the frequency spacing of the bands / rasters in the existing system.

[0125] The synchronization signal / broadcast signal may be transmitted in a band / raster that is more restricted than existing systems (e.g., with shorter frequency intervals and longer time intervals).

[0126] Furthermore, the UE may search for synchronization signals / broadcast signals based on information obtained before the cell selection / cell search procedure.

[0127] The search operation for synchronization / broadcast signals based on the information may be a mandatory operation for the UE, or it may be an optional operation.

[0128] This information may be provided / configured by the operator / service provider / Mobile Network Operator (MNO) / Mobile Virtual Network Operator (MVNO) / vendor, for example, using a specific method.

[0129] The specific method may be, for example, at least one of the methods described in Embodiment 1-1-A below.

[0130] Figure 5 shows an example of the operation up to initial access according to the first embodiment. The UE monitors multiple frequencies and receives a synchronization signal / broadcast signal on the first carrier (perch carrier) (searches for the first carrier). Next, based on the synchronization signal / broadcast signal, the UE searches for another first carrier or receives system information corresponding to that first carrier. Next, based on the system information, the UE searches for another first carrier or determines the appropriate cell corresponding to the system information.

[0131] Note that the UE operations described in Figure 5 may only be a part of the operations required before initial access, and other operations may also be performed.

[0132] The UE may follow at least one of the embodiments 1-1 to 1-4 below for its operation up to the initial access.

[0133] <<Embodiment 1-1>> Embodiment 1-1 relates to the frequency at which the UE first searches for a synchronization signal / broadcast signal.

[0134] <<<Embodiment 1-1-A>>> Embodiment 1-1-A describes the band / raster that the UE searches [first].

[0135] In this disclosure, the band may be referred to as the perch band, the first band, etc. In this disclosure, the band may correspond to the perch carrier / first carrier band.

[0136] In this disclosure, the raster may be referred to as a perch raster, a first raster, etc. In this disclosure, the raster may be a raster corresponding to a perch carrier / first carrier.

[0137] The band / raster may be predefined / configured for each Public Land Mobile Network (PLMN) / band / frequency range (FR) / service / use case / slice, for example.

[0138] The band / raster may be configured / updated, for example, by settings made by a higher layer (e.g., settings made by RRC / Non-Access Stratum (NAS) / application / OS (Operating System)).

[0139] The band / raster configuration / update may be performed, for example, by at least one of the following: • Writing to the Subscriber Identity Module (SIM); • Over-the-Air (OTA) firmware update; • Pre-configuration via sidelink (e.g., setting default parameters by a new protocol / layer / network function when there is no information from the Access Stratum (AS), which may also be called AS information, AS data, etc.).

[0140] The band / raster may be set / updated by other information, for example (e.g., location information (e.g., Global Positioning System (GPS) information)).

[0141] <<<Embodiment 1-1-B>>> The band / raster that the UE searches [first] may be selected / determined from, for example, a specific list of candidates.

[0142] The specific candidate may, for example, be a candidate in a specific frequency range. For example, the specific candidate may be a candidate only in a specific frequency range (e.g., FR1 / FR2 (FR2-1 / 2-2)) or a candidate only in a specific band (e.g., a capacity band / coverage band).

[0143] The specific candidate may be defined, for example, by bands [only] within a specific frequency range (e.g., 0 to X*1000 MHz) (Option 1-1-B-1).

[0144] The specific candidate may be defined, for example, as a specific GSCN step / raster interval (e.g., X MHz (e.g., X is 2 or less)) (Option 1-1-B-2).

[0145] The specific candidate may have a restricted GSCN / raster range / [frequency] candidate position within the frequency range / band compared to existing systems (e.g., 5G NR) (e.g., smaller / fewer) (Option 1-1-B-3).

[0146] The candidate positions may be defined by a specific number, for example (for example, it may be 100 or less, or 10 or less).

[0147] The candidate position may, for example, indicate a specific position (e.g., the center position) within the channel bandwidth (CBW).

[0148] The candidate location may be placed, for example, in a specific (e.g., minimum / maximum) physical resource block / resource element (or any combination thereof).

[0149] Bands / rasters other than the first band / raster that the UE searches may be subject to the same or different options (for example, options 1-1-B-1 to 1-1-B-3) as the first band / raster that the UE searches.

[0150] For example, the band / raster corresponding to the anchor carrier / second carrier (which may also be called the anchor band / raster) may have common / separate options (e.g., options 1-1-B-1 to 1-1-B-3) applied to it, as well as the band / raster that the UE initially searches.

[0151] For a given band / raster, one or more bands (e.g., two, three, or four) may be defined within that band to be searched by a synchronized raster (these rasters may be called, for example, per-band perch-like rasters).

[0152] For a given band / raster, one or more bands (e.g., two, three, or four) may be defined to be searched within a specific FR / frequency group (these defined bands may be called, for example, perch-like bands).

[0153] <<<Embodiment 1-1-C>>> The UE may search for the synchronization signal / broadcast signal by making certain assumptions / predictions regarding the synchronization signal / broadcast signal.

[0154] The specific assumption / premise may, for example, be an assumption / premise relating to at least one of the following: • Subcarrier interval [range] • Physical cell ID [range] • (Signal) sequence [range] • Time [range].

[0155] The specific assumption / premise (or its implementation) may be defined / established, for example, by using at least one method described in Embodiment 1-1-A above.

[0156] <<<Embodiment 1-1-D>>> The band / raster corresponding to the first carrier may be defined using a different framework from other band / rasters (ordinary bands / rasters, for example, corresponding to carriers other than the first carrier).

[0157] For example, the band corresponding to the first carrier may be defined as a separate band (which may be called a perch channel band) from existing bands (for example, those defined up to 5G NR) (e.g., Time Division Duplex (TDD) bands, Frequency Division Duplex (FDD) bands, and Supplementary UL (SUL) bands). By designing the band corresponding to the first carrier individually in this way, a more scalable network can be realized.

[0158] The band corresponding to the first carrier (perch channel band) may be, for example, a band that enables DL / UL / TDD / FDD / Half Duplex (HD) / Full Duplex (FD) / Subband FD (SBFD) / Personal Communications Service (PCS) band [only].

[0159] The bands corresponding to the first carrier (perch channel bands) may be bands in which DL / UL / TDD / FDD / Half Duplex (HD) / Full Duplex (FD) / Subband FD (SBFD) / Personal Communications Service (PCS) bands [only] are unavailable.

[0160] For example, the band corresponding to the first carrier may be defined at a frequency position different from or common to other / normal / existing GSCNs.

[0161] For example, the bands corresponding to the first carrier do not have to coincide with some or all of the other / normal / existing GSCNs, and may be defined based on a different framework / formula / correspondence / table than the other / normal / existing GSCNs.

[0162] According to Embodiment 1-1, the frequency at which the UE initially searches for the synchronization signal / broadcast signal can be appropriately defined.

[0163] <<Embodiment 1-2>> Embodiment 1-2 relates to the operation of a UE after the UE has detected a synchronization signal / broadcast signal.

[0164] The UE may perform at least one of the operations described in the following embodiments 1-2-A to 1-2-D.

[0165] The UE may perform at least two of the operations described in the following embodiments 1-2-A to 1-2-D simultaneously, or it may not perform them simultaneously.

[0166] The UE may perform at least one of the operations described in embodiments 1-2-A to 1-2-D below by information about the AS, such as synchronization signals / notification signals / system information (e.g., a master information block).

[0167] <<<Embodiment 1-2-A>>> The UE may search for another [candidate] frequency based on the quality / notification content of the [discovered] synchronization signal / notification signal.

[0168] The location of the other [candidate] frequency (band / raster) may be set / defined using at least one of the methods described in Embodiments 1-1-A / 1-1-B above.

[0169] The notification may include, for example, at least one of the following: • A list of candidate frequencies / bands / cell IDs to search. • A list of offsets / frequency differences for the frequencies / bands to search. • The priority / order of the frequencies / bands to search.

[0170] The cell ID may be, for example, a physical cell ID (PCI). If the PCI is generated based on multiple sequence signals, the UE may be notified of the values ​​[or candidates] of the multiple sequence signals.

[0171] The offset / frequency difference does not necessarily have to indicate, for example, the range of frequencies being searched.

[0172] The offset / frequency difference may, for example, indicate any combination of synchronization signals / system information (e.g., SIB / MIB), or it may indicate the range in which valid cells / signals (synchronization signals / broadcast signals) exist or do not exist.

[0173] The order may, for example, implicitly indicate the priority.

[0174] The UE may set / notify (determine) the location of the other [candidate] frequency (band / raster) by at least one of the following methods: • A value / bitmap indicating an entry / row / index in a correspondence / table / list defined in the specification. • An RRC payload (which may be written using ASN.1 (Abstract Syntax Notation One) notation). • Information / bits in a specific setting at the physical layer. • A sequence used to generate a reference signal (e.g., a synchronization signal / other signal). • At least one method as described in Embodiment 1-1-A above.

[0175] The UE may search for other candidate frequencies, for example, based on whether the quality of the discovered synchronization / broadcast signal (e.g., RSRP / RSRQ / SINR) is above or below a certain threshold.

[0176] The specific threshold may be defined in advance by the specifications, set by specific signaling (e.g., a coordinating signal / announcement signal / system information), set by at least one of the methods described in Embodiment 1-1-A above, or determined based on a combination of at least two of these.

[0177] <<<Embodiment 1-2-B>>> The UE may search for / monitor a DL control channel (e.g., PDCCH) that transmits system information (e.g., SIB).

[0178] The system information may, for example, be system information corresponding to a first carrier that is discovered / receives a synchronization signal.

[0179] The DL control channel may be transmitted, for example, on a first carrier, or on a second carrier (anchor carrier) corresponding to the first carrier.

[0180] The location [list] of the resources (e.g., time / frequency resources) of the DL control channel may be notified / set / determined by at least one of the following: - Information about the AS by synchronization signals / broadcast signals / system information (e.g., master information block); - Specification by specification; - At least one method described in Embodiment 1-1-A above.

[0181] The UE may determine the location [list] of resources (e.g., time / frequency resources) for the DL control channel based on information about at least one of the following: • The start / end location / number of resource elements / physical resource blocks / symbols / slots to which the DL control channel (PDCCH) is transmitted. • The CORESET / search space setting (e.g., CORESET zero (#0) / search space zero (#0)) for the DL control channel (PDCCH). • The offset from a specific (time / frequency) reference point / location.

[0182] The UE may acquire specific information contained in the DL control channel.

[0183] The specific information may include at least one of the following: a list of resources (e.g., time / frequency resources) on a DL channel (e.g., PDSCH) that transmits system information (e.g., SIB); and information about the AS via synchronization signals / broadcast signals / system information (e.g., master information block).

[0184] <<<Embodiment 1-2-C>>> The UE may search for / monitor DL ​​channels (e.g., PDSCH) that transmit system information (e.g., SIB).

[0185] The location [list] of the DL channel resources (e.g., time / frequency resources) may be notified / set / determined / judged based on at least one of the methods described in Embodiment 1-2-B above.

[0186] <<<Embodiment 1-2-D>>> The UE may receive / search for on-demand system information (e.g., SIB / MIB).

[0187] The on-demand system information may be transmitted, for example, if there is no synchronization signal / system information available to the UE, if the UE cannot receive the synchronization signal / system information, or if there is insufficient synchronization signal / system information (that the UE should receive).

[0188] The on-demand system information may be transmitted by a UE trigger.

[0189] For example, if no synchronization signal / system information is available to the UE, if the UE cannot receive the synchronization signal / system information, or if there is insufficient synchronization signal / system information (that the UE should receive), the UE may send a request for the transmission of such on-demand system information (e.g., a UL signal / WUS) to the network / base station.

[0190] For example, if no synchronization signals / system information are available to the UE, if the UE cannot receive synchronization signals / system information, or if there is insufficient synchronization signals / system information (that the UE should receive), the UE may obtain information regarding the request.

[0191] According to Embodiment 1-2, the UE operation after the detection of a single synchronization signal / notification signal can be appropriately defined.

[0192] <<Embodiment 1-3>> Embodiment 1-3 relates to the operation of the UE after the UE has discovered system information corresponding to the synchronization signal / broadcast signal.

[0193] The UE may search for other candidate frequencies based on the system information it receives.

[0194] The search / location of the other [candidate] frequency (band / raster) may follow at least one method described in Embodiment 1-2-A above.

[0195] The UE may determine / judge / decide which cells to connect / camp (which may also be called suitable cells).

[0196] The method / criteria for determining a suitable cell may be the same as existing methods / criteria (e.g., those specified in 5G NR), or it may be notified / set / specified by at least one of the methods described in Embodiment 1-1-A above.

[0197] For example, at least one of the following may be notified to the UE: whether or not it is a valid cell (quality / threshold), whether or not it is accessible (for a particular type of UE), and the priority of the cell to which it is being accessed. Based on this notification, the UE may determine whether or not it is a valid cell.

[0198] The UE may (or attempt to) camp / connect to a cell.

[0199] According to Embodiment 1-3, the UE operation after the discovery of system information corresponding to the synchronization signal / notification signal can be appropriately defined.

[0200] <<Embodiment 1-4>> Embodiment 1-4 may be applied to the UE operation of Embodiments 1-1 / 1-2 / 1-3, or to the UE operation before or after Embodiments 1-1 / 1-2 / 1-3.

[0201] The UE may perform a particular UE operation based on information obtained before that particular UE operation. The operation according to Embodiment 1-4 may be, for example, a UE-mandatory operation.

[0202] For example, the UE may retain information about a specific frequency range acquired within a specific period and use / apply it to the UE operation.

[0203] The specific period and the period for retaining the information may, for example, be a period specified in advance by the specifications (e.g., always / X months / X days / X hours / X minutes / X seconds), or may be notified / set / specified by at least one of the methods described in Embodiment 1-1-A above.

[0204] The information relating to the specific frequency range may be, for example, information relating to at least one of the following: • Frequency range (e.g., FR1 / FR2 (FR2-1 / FR2-2)) / perch band / perch raster; • Retention of frequency [candidate] positions; • Retention of priority for frequency range (e.g., FR1 / FR2 (FR2-1 / FR2-2)) / perch band / perch raster / frequency [candidate] positions).

[0205] The UE may hold only the synchronization signal, system information, and information notified by at least one of the methods described in Embodiment 1-1-A above.

[0206] The UE may retain information by overwriting the previously held information with information notified by a synchronization signal, system information, and at least one of the methods described in Embodiment 1-1-A above.

[0207] According to Embodiment 1-4, by defining the period for which the UE retains acquired information, it is possible to reduce signaling overhead during cell selection / connection.

[0208] Furthermore, the UE may decide to perform different UE operations from those described in the above embodiments 1-1 / 1-2 / 1-3 based on the UE's AS (capabilities) / NAS capabilities / policy / higher layer settings.

[0209] According to the first embodiment described above, it is possible to realize appropriate reception regulations and operation of synchronization signals / broadcast signals.

[0210] <Second Embodiment> The second embodiment relates to the reception regulations and operation of synchronization signals / broadcast signals.

[0211] The second embodiment may be applied, for example, in multi-carrier-based initial access.

[0212] Figure 6 shows an example of the operation up to initial access according to the second embodiment. First, the UE monitors multiple frequencies and receives a synchronization signal / broadcast signal on a first carrier (perch carrier). Next, based on the synchronization signal / broadcast signal, the UE performs at least one of the following: searching for a corresponding second carrier (anchor carrier), receiving system information for the first carrier, and searching for another first carrier.

[0213] In the example shown in Figure 6, after receiving system information from a first carrier, the UE performs at least one of the following based on the system information from that first carrier: a search for another first carrier and a search for a corresponding second carrier.

[0214] In the example shown in Figure 6, after searching for a corresponding second carrier, the UE performs at least one of the following based on the synchronization signal / broadcast signal of the second carrier: searching for another first carrier, searching for another second carrier, receiving system information for the corresponding first carrier, and receiving system information for the second carrier.

[0215] In the example shown in Figure 6, after receiving system information from the second carrier, the UE performs at least one of the following based on the system information from the second carrier: a search for another first carrier and a search for another second carrier.

[0216] Note that the UE operations described in Figure 6 may only be a part of the operations required before initial access, and other operations may also be performed.

[0217] The UE may follow at least one of the embodiments 2-1 to 2-4 below for its operation up to the initial access.

[0218] <<Embodiment 2-1>> Embodiment 2-1 relates to the frequency at which the UE first searches for a synchronization signal / broadcast signal.

[0219] This frequency may also be called a perch carrier.

[0220] The UE may follow at least one of the procedures / operations described in Embodiments 1-1-A to 1-1-D of Embodiment 1-1 above.

[0221] Specific assumptions / premise regarding synchronization / broadcast signals may include (furthermore) at least one of the following: • The subcarrier interval used for synchronization / broadcast signals is limited to a specific value (e.g., 7.5 kHz / 15 kHz / 30 kHz). • The physical cell ID set / assumed for at least one of the perch carrier and the cell corresponding to the perch carrier is set / defined to a different value / range than that of the other carrier / cell. • The time position of the synchronization / broadcast signal is a specific timing based on timing obtained from another system (e.g., GNSS).

[0222] The physical cell ID set / expected to be in at least one of the parch carrier and the cell corresponding to the parch carrier may be defined / set by a specific value / range (e.g., 0 to 512), and the PSS / SSS associated with the physical cell ID may be defined / set by a specific value / range (e.g., a value / range smaller / restricted than other / existing PSS / SSS).

[0223] For example, a portion of the synchronization signal (e.g., PSS) may be transmitted on the perch carrier, and the remaining portion of the synchronization signal (e.g., SSS) may be transmitted on the anchor carrier. The UE may determine the corresponding physical cell ID based on the PSS / SSS.

[0224] <<Embodiment 2-2>> Embodiment 2-2 relates to the operation of a perch carrier after the detection of a synchronization signal / notification signal.

[0225] The synchronization signal / broadcast signal in a perch carrier may also be called the perch synchronization signal / broadcast signal.

[0226] The UE may perform at least one of the operations described in the following embodiments 2-2-1 to 2-2-4.

[0227] The UE may perform at least two of the operations described in the following embodiments 2-2-1 to 2-2-4 simultaneously, or it may not perform them simultaneously.

[0228] <<<Embodiment 2-2-1>>> The UE may search for a frequency / band / carrier / raster associated with the perch synchronization signal / broadcast signal (or perch carrier).

[0229] The frequency / band / carrier / raster in question may also be called the anchor frequency / band / carrier / raster.

[0230] The candidate frequencies / bands / raster locations to search may be defined / set, for example, by at least one method described in Embodiments 1-1-A / 1-1-B above.

[0231] The UE may search for and monitor reference signals, synchronization signals, broadcast signals, and system information in the anchor frequency / band / carrier / raster.

[0232] <<<Embodiment 2-2-2>>> The UE may search for another perch frequency based on the quality / notification content of the perch synchronization signal / notification signal that it has discovered.

[0233] The location of the other perch frequency (band / raster) may be set / defined using at least one of the methods described in Embodiments 1-1-A / 1-1-B above.

[0234] <<<Embodiment 2-2-3>>> The UE may search for / monitor DL ​​channels (e.g., PDCCH / PDSCH) that transmit system information corresponding to the perch carrier.

[0235] The UE may follow at least one of the methods described in Embodiments 1-2-B / 1-2-C for searching / monitoring the DL channel.

[0236] <<<Embodiment 2-2-4>>> The UE may receive / search on-demand system information (e.g., SIB / MIB) in the perch carrier / anchor carrier.

[0237] The on-demand system information may be transmitted, for example, if there is no synchronization signal / system information available to the UE, if the UE cannot receive the synchronization signal / system information, or if there is insufficient synchronization signal / system information (that the UE should receive).

[0238] The on-demand system information may be transmitted by a UE trigger.

[0239] For example, if no synchronization signal / system information is available to the UE, if the UE cannot receive the synchronization signal / system information, or if there is insufficient synchronization signal / system information (that the UE should receive), the UE may send a request for the transmission of such on-demand system information (e.g., a UL signal / WUS) to the network / base station.

[0240] For example, if no synchronization signals / system information are available to the UE, if the UE cannot receive synchronization signals / system information, or if there is insufficient synchronization signals / system information (that the UE should receive), the UE may obtain information regarding the request.

[0241] According to Embodiment 2-2, the UE operation after detection of the perch synchronization signal / notification signal can be appropriately defined.

[0242] <<Embodiment 2-2A>> Embodiment 2-2A relates to the operation of a perch carrier after the discovery of system information.

[0243] System information in a perch carrier may also be called perch system information.

[0244] The UE may search for a different perch frequency based on the system information it receives.

[0245] The method for searching for the other perch frequency (band / raster) may follow at least one of the methods described in the first embodiment (for example, Embodiments 1-3).

[0246] Furthermore, the UE may search for relevant anchor frequencies / bands / carriers / rasters based on the system information it receives.

[0247] The method for searching for the anchor frequency / band / carrier / raster may follow at least one of the methods described in Embodiment 2-2-1 above.

[0248] The UE may receive / search on-demand system information (e.g., SIB / MIB) on the perch carrier / anchor carrier.

[0249] The method for receiving / searching the on-demand system information may follow at least one of the methods described in Embodiment 2-2-4 above.

[0250] According to Embodiment 2-2A, the UE operation after the discovery of perch system information can be appropriately defined.

[0251] <<Embodiment 2-3>> Embodiment 2-3 relates to the operation after the discovery of the relevant anchor frequency / band / carrier / raster.

[0252] The UE may receive synchronization signals / broadcast signals in the anchor frequency / band / carrier / raster.

[0253] The synchronization signal / notification signal may be called, for example, an anchor synchronization signal / notification signal.

[0254] The UE may search for a different perch / anchor frequency based on the quality / notification content of the anchor synchronization signal / notification signal.

[0255] The UE may receive / monitor DL ​​channels (e.g., PDCCH / PDSCH) that transmit system information in the perch / anchor carrier.

[0256] The UE may receive / search on-demand system information (e.g., SIB / MIB) on the perch carrier / anchor carrier.

[0257] The method for receiving / searching the on-demand system information may follow at least one of the methods described in Embodiment 2-2-4 above.

[0258] According to Embodiment 2-3, the UE operation after the discovery of the relevant anchor frequency / band / carrier / raster can be appropriately defined.

[0259] <<Embodiment 2-3A>> Embodiment 2-3A relates to the operation of the anchor carrier after the discovery of system information.

[0260] System information in an anchor carrier may also be called anchor system information.

[0261] The UE may search for a different perch frequency based on the system information it receives.

[0262] The method for searching for the other perch frequency (band / raster) may follow at least one of the methods described in the first embodiment (for example, Embodiments 1-3).

[0263] Furthermore, the UE may search for relevant anchor frequencies / bands / carriers / rasters based on the system information it receives.

[0264] The method for searching for the anchor frequency / band / carrier / raster may follow at least one of the methods described in Embodiment 2-2-1 above.

[0265] The UE may receive / search on-demand system information (e.g., SIB / MIB) on the perch carrier / anchor carrier.

[0266] The method for receiving / searching the on-demand system information may follow at least one of the methods described in Embodiment 2-2-4 above.

[0267] According to Embodiment 2-3A, the UE operation after the discovery of anchor system information can be appropriately defined.

[0268] <<Embodiment 2-4>> If the operation according to Embodiments 2-1 / 2-2 / 2-2A / 2-3 / 2-3A is completed in a specific procedure, the UE may determine that an appropriate perch / anchor frequency (or group thereof) has been detected.

[0269] The UE may perform the determination / assessment / decision of appropriate cells and the determination of the frequencies / carriers (or groups thereof) to connect / camp.

[0270] The UE may determine the frequencies / carriers (or groups thereof) to connect / camp based on criteria / standards relating to multiple (perch / anchor) carriers.

[0271] The specific procedure in question may, for example, mean that certain conditions are met within a specific frequency range / period.

[0272] The specific frequency range / period may be, for example, at least one of a plurality of predetermined frequency ranges / periods (e.g., all of them), a frequency range / period corresponding to the UE, and a frequency range / period determined by the higher layer settings.

[0273] The specific frequency range in question may be, for example, a carrier band, frequency range, or Radio Access Technology (RAT) defined or set as a perch / anchor.

[0274] The fulfillment of such specific conditions may mean, for example, that a certain number (e.g., N) or more carriers that meet a specific criterion are found, and that the operations relating to the above embodiments 2-1 / 2-2 / 2-2A / 2-3 / 2-3A are performed a specific number of times (e.g., Nx times).

[0275] The specific criteria / standards may be, for example, criteria / standards based on the reception quality of the signal (e.g., RSRP / RSRQ / SINR). The UE may consider the reception quality of at least one of the perch carrier and the anchor carrier. Which carrier's reception quality is considered may be specified in advance in the specifications, or it may be determined by at least one method described in Embodiment 1-1-A.

[0276] If the UE considers the reception quality of both the perch carrier and the anchor carrier, the reception quality may be considered as an average (or bandwidth-weighted average) value.

[0277] The specific criteria / standard / N / Nx may be defined in advance in the specifications, or may be determined by at least one method described in Embodiment 1-1-A.

[0278] For at least one of the operations in the above embodiments 2-1 to 2-4, a different operation may be applied based on the type of UE, or a specific operation may be omitted (may not be performed).

[0279] For example, certain types of UEs may perform single-carrier-based initial access and may not have to perform multi-carrier-based initial access.

[0280] The particular type of UE may be at least one of the following UEs / terminals: • [enhanced] reduced capability devices ([e] RedCap) terminals; • Narrowband (NB-) IoT terminals; • Category (Cat) X terminals (e.g., X is 1 / M1 / NB1 / NB2 / 4); • Half-duplex UEs; • Ambient IoT terminals; • [LP-] WUS-enabled UEs; • Vehicle-to-Everything (V2X) / sidelink-enabled UEs; • IAB-MT (Mobile Termination); • Non-terrestrial network (NTN)-enabled UEs.

[0281] For at least one of the operations in the above embodiments 2-1 to 2-4, a different operation may be applied based on the service type of the UE, or a specific operation may be omitted (may not be performed).

[0282] The service type of a UE may be determined, for example, according to at least one of the following: slice ID, UE identifier / ID, temporary mobile subscriber identity (TMSI), establishment cause, communication purpose, and priority.

[0283] Furthermore, the service types of the UE may include communications on the control (C-) plane [only] (e.g., at least one of initial registration, registration update, and location registration / update), or communications involving the establishment of user (U-) plane sessions (e.g., for URLLC (Ultra Reliable and Low Latency Communications) / IoT / XR (Cross Reality) / voice communications / video communications / emergency communications / NTN / NPN (Non-Public Network) / unlicensed (shared) spectrum / sharing with other RATs / 6G-only communications).

[0284] Furthermore, the UE may decide to perform different UE operations from those described in the above embodiments 2-1 to 2-4 based on the UE's AS (capabilities) / NAS capabilities / policy / higher layer settings.

[0285] According to the second embodiment described above, appropriate reception rules and operations for synchronization signals / broadcast signals can be realized in multi-carrier-based initial access.

[0286] <Third Embodiment> The third embodiment relates to the operation in connection / camping to a cell.

[0287] The UE may, during camp-on, RRC idle, or RRC inactive, acquire (part of) information regarding synchronization signals / broadcast signals / paging on another single or multiple carriers (e.g., perch / anchor carriers) based on the signaling regarding synchronization signals / broadcast signals / paging on a single carrier (e.g., perch carrier).

[0288] Furthermore, the UE may acquire information (the rest of it) regarding synchronization signals / broadcast signals / paging on another single or multiple carrier (e.g., perch / anchor carrier).

[0289] The information (part or remainder) may include at least one of the following: • Information regarding [rough / fine] time / frequency synchronization. • Information regarding beam (e.g., QCL type (A / B / C / D)) / antenna port. • Information regarding power / AGC (Automatic Gain Control). • Information regarding RACH / parameters. • Information regarding PDCCH CORESET / search space. • Information regarding frequency / time domain resource allocation for PDSCH / PUSCH. • Information regarding PUCCH resources. • Information regarding TDD / slot settings. • Information regarding subcarrier spacing. • Logical channel information, e.g., BCCH (Broadcast Control Channel) / PCCH (Paging Control Channel) settings.

[0290] This information may be set, for example, as a carrier / band-specific list of one or more parameters included in the system information of an existing system (5G NR).

[0291] This information may be associated and configured for each different perch / anchor / data carrier.

[0292] The UE may determine, based on specific UE capabilities, conditions relating to a particular carrier, and specific settings relating to a particular carrier, which carrier (or combination of carriers) to use for receiving / monitoring system information (e.g., SIBx) / paging PDCCH / paging PDSCH.

[0293] A UE may determine, based on specific UE capabilities, conditions relating to a particular carrier, and specific settings relating to a particular carrier, which carrier (or combination of carriers) to use for at least one of the following: RACH transmission, Random Access Response (RAR) PDCCH / PDSCH reception / monitoring.

[0294] Specific UE capabilities, conditions for specific carriers, and specific settings for specific carriers may, for example, be capabilities / conditions / settings relating to at least one of the following: • Strength and quality of anchor / perch synchronization signals against thresholds. • Location / area information. • UE type (e.g., UE contract / communication type). • Settings based on anchor / perch broadcast information. • Whether specific relationships are met / not met for multiple carriers (e.g., perch / anchor / data carrier).

[0295] The specific relationship in question may relate to at least one of the following, for example: • QCL types of multiple carriers (A / B / C / D). • Power [difference] (e.g., power difference is less than or equal to a certain value). • Round Trip Time (RTT) (e.g., RTT is less than or equal to a certain value). • Frequency / frequency range (intra- / inter-). • Contiguous or not. • Timing advance (TA) groups (Timing Advance Groups (TAGs)) are the same or different. • PUCCH resource settings are configured or not configured (e.g., the PUCCH SCell group may be deemed to satisfy the relationship). • Groups relating to a specific area in the upper layer are the same (e.g., at least one of the TA index, TA command, tracking area (code), RAN based notification area pool, AMF pool, MME pool is the same).

[0296] The conditions for a particular carrier being met may include, for example, at least one of the following: • Layer 1 / Layer 3 measurements (L1 / L3 measurements) have been completed within a specific period during idle / connected states. • Basic cell information (e.g., system information) has been acquired. • The cell is known / unknown. • DL / UL multi-carrier operation is supported.

[0297] Different / multiple carriers (e.g., perch / anchor / data carriers) may be arranged / defined in coexistence with frequencies / bands defined in existing systems (e.g., 4G LTE / 5G NR) or may be defined in existing RATs.

[0298] According to the third embodiment described above, the operation in connection / camping to the cell can be appropriately defined.

[0299] <Modifications> The following terms and operations relate to each embodiment of this disclosure.

[0300] The “specific period” described in each embodiment of this disclosure may, for example, be defined in advance by specification, determined based on specific parameters set from the base station / NW, determined based on UE capabilities, or determined based on at least a combination of these.

[0301] The “specific period” described in each embodiment of this disclosure may be, for example, a period determined by a specific time width, starting from a specific reference point.

[0302] The specific reference point may be, for example, the time of transmission or reception of a specific DL / UL signal, and at least one of the reference timings / times set by the base station (e.g., system frame number (SFN) / slot number / symbol number).

[0303] The time domain units of the specific reference point may be, for example, symbol units, slot units, wireless frame units, system frame units, subframe units, subms units, ms units, or s units.

[0304] The specific time interval may be defined in advance by the specifications, determined based on specific parameters set by the base station / network, determined based on UE capabilities, or determined based on a combination of at least two of these.

[0305] This specific time interval may vary, for example, depending on the SCS.

[0306] This specific time window may vary, for example, depending on the timing advance value of the UE.

[0307] The specific time window may be defined / set / determined, for example, as a time window from the specific reference point.

[0308] The specific time interval may be defined / set / determined, for example, as a delay (application delay / processing delay) from the specific reference point.

[0309] The UE may determine the specific period based on a comparison with a specific value. For example, the UE may determine the specific period as the maximum or minimum value among a predetermined / set / determined period and the specific value.

[0310] The specific value in question may be, for example, n symbols / slots / ms. n may be, for example, 1, or any integer greater than or equal to 1.

[0311] The specific value may be defined in advance in the specifications, determined based on specific parameters set by the base station / network, determined based on UE capabilities, or determined based on a combination of at least two of these.

[0312] This specific value may vary depending on, for example, the SCS.

[0313] In each embodiment of this disclosure, “carrier / band” may be read as “cell.” In this case, “cell” may be a special cell (SpCell (e.g., PCell / PSCell)) / PCell / (DC)PSCell / (active)SCell, or any cell that satisfies certain conditions.

[0314] Each embodiment of the present disclosure may be applied to a specific UE state / mode (e.g., at least one of the idle state, inactive state, and RRC connected state). Different behaviors may be applied to each embodiment of the present disclosure based on the UE state / mode.

[0315] The “specific settings / notifications” described in each embodiment of this disclosure may be performed, for example, using RRC signaling / MAC CE / DCI.

[0316] For each embodiment of this disclosure, the "specific settings / notifications" may be associated with an identifier / index, for example, with the parameters (lists) that are set / notified using RRC signaling / MAC CE / DCI.

[0317] In this case, the UE may determine which parameters (lists) are activated / applied / used (or deactivated / not applied / not used) by being notified of the identifier / index through another notification (e.g., MAC CE / DCI).

[0318] The identifier / index may be implicitly associated with the parameter / list based on the order of the list set using RRC signaling, or it may be associated with the parameter / list by explicitly assigning a number to it.

[0319] In at least one of the embodiments of this disclosure, the UE may transmit a response signal to the received signal (e.g., NACK (negative response) / ACK (affirmative response) / feedback / retransmission request).

[0320] The UE may use RRC signaling to set, modify, and release multiple parameter lists based on an add / modify list (e.g., AddModlist) and a release list (e.g., releaselist).

[0321] The “specific settings / notifications” described in each embodiment of this disclosure may be, for example, made using system information (SI) / SIB RRC messages, or using UE-specific RRC messages for a UE in RRC connection (e.g., RRCReconfiguration). For example, the “specific settings / notifications” described in each embodiment of this disclosure may be SS / PBCH blocks / SIB1 / SIBx / dedicated RRC settings / RRC release / RRC setup for a specific (one or more) carrier / band.

[0322] The “specific settings / notifications” described in each embodiment of this disclosure may be, for example, a DCI (DCI format) to which a CRC is assigned that is scrambled using a specific RNTI (e.g., X-RNTI).

[0323] The specific RNTI may be, for example, an existing RNTI (e.g., NES (network energy crossing)-RNTI, SI-RNTI) or a novel RNTI.

[0324] The DCI format in question may be, for example, an existing DCI format or a new DCI format.

[0325] Any number described in each embodiment of this disclosure may be specified in advance, determined based on specific parameters set from the base station / NW, determined based on UE capability, or determined based on a combination of at least two of these.

[0326] With respect to any parameter described in each embodiment of this disclosure, if the base station / network does not set the parameter, the UE may determine / decide to perform the default operation.

[0327] The default action may be at least one of the following: - Do not perform / cancel the action. - Repeat the previous action (a certain number of times). - Perform an RRC release. - Perform an RRC re-establishment. - Send a specific notification to the base station / network. - Send a specific notification to the upper layer (within the UE).

[0328] If any of the parameters described in each embodiment of this disclosure are not set by the base station / network, the UE may determine / decide to use the default value for that parameter.

[0329] The default value may be at least one of the following: • A specific value (e.g., 0 / 1). • The value used immediately before. • The value that was set / notified immediately before. • A value specified in the specifications beforehand. • A parameter value from another setting / notification. • A specific timer value.

[0330] If a UE is unable to perform a certain UE operation as described in each embodiment of this disclosure, the UE may determine / decide to perform an alternative default operation.

[0331] In at least one of the embodiments of this disclosure, a particular reference signal satisfying a particular criterion / condition may mean that the received quality (e.g., RSRP / SINR) of the particular reference signal is greater than (or equal to) a particular threshold.

[0332] <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.

[0333] 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.

[0334] 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.

[0335] Furthermore, the notification of arbitrary information to the UE in the above-described embodiment may be periodic, semi-persistent, or aperiodic.

[0336] <<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.

[0337] 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.

[0338] If the above notice is made by the UCI, the notice may be transmitted using PUCCH or PUSCH.

[0339] Furthermore, the notification of any information from the UE in the above-described embodiment may be periodic, semi-persistent, or aperiodic.

[0340] <<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.

[0341] 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).

[0342] 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).

[0343] 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)).

[0344] If the above conditions are not met, UE / BS may follow the behavior specified in existing 3GPP releases.

[0345] (Note) The following inventions are added with respect to one embodiment of the present disclosure. [Note 1-1] A terminal having a receiving unit that monitors a plurality of frequencies, detects a first carrier common to a plurality of terminals, and receives a synchronization signal transmitted on the first carrier, and a control unit that controls, based on the synchronization signal, receiving system information corresponding to the first carrier, searching for another first carrier, and at least one of the above. [Note 1-2] The terminal according to Note 1-1, wherein the control unit controls, based on the system information, at least one of searching for another first carrier and determining an appropriate cell. [Note 1-3] The terminal according to Note 1-1 or Note 1-2, wherein the system information is transmitted on a second carrier specific to the terminal that corresponds to the first carrier. [Note 1-4] The terminal according to any one of Notes 1-1 to 1-3, wherein the band corresponding to the first carrier is a different band from the Time Division Duplex (TDD) band, Frequency Division Duplex (FDD) band, and supplemental uplink band. [Note 2-1] A terminal having: a receiving unit that monitors multiple frequencies, detects a first carrier common to multiple terminals, and receives a synchronization signal transmitted on the first carrier; and a control unit that controls, based on the synchronization signal, the reception of first system information corresponding to the first carrier, the search for a second carrier specific to the terminal that corresponds to the first carrier, and the search for another first carrier. [Note 2-2] The terminal according to Note 2-1, wherein the control unit controls, based on the first system information, at least one of the search for the second carrier and the search for another first carrier. [Note 2-3] The terminal according to Note 2-1 or Note 2-2, wherein the control unit controls, based on the synchronization signal transmitted on the second carrier, at least one of the reception of first system information corresponding to the first carrier, the search for another first carrier, and the search for another second carrier.[Appendix 2-4] The terminal according to any one of Appendix 2-1 to 2-3, wherein the receiving unit receives information about the synchronization signal transmitted on at least one of the other first carrier and the second carrier based on the synchronization signal transmitted on the first carrier.

[0346] (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.

[0347] Figure 7 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).

[0348] 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.

[0349] 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.

[0350] 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))).

[0351] 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.

[0352] 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.

[0353] 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).

[0354] 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.

[0355] Furthermore, the user terminal 20 may communicate in each CC using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD).

[0356] 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.

[0357] 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.

[0358] 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.

[0359] The user terminal 20 may be a terminal that supports at least one of the following communication methods: LTE, LTE-A, 5G, etc.

[0360] 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).

[0361] 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.

[0362] 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.

[0363] 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.

[0364] 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.

[0365] 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.

[0366] 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.

[0367] 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.

[0368] 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.

[0369] 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.

[0370] 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.

[0371] 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.

[0372] 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.

[0373] 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).

[0374] (Base Station) Figure 8 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.

[0375] 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.

[0376] 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.

[0377] 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.

[0378] 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.

[0379] 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.

[0380] 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.

[0381] 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.

[0382] 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.

[0383] 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.

[0384] 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.

[0385] 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.

[0386] 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.

[0387] 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.

[0388] 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.

[0389] 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.

[0390] 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.

[0391] 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.

[0392] 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.

[0393] The transmitting / receiving unit 120 may transmit a synchronization signal on a first carrier common to multiple terminals detected by monitors of multiple frequencies. The control unit 110 may use the synchronization signal to instruct at least one of the following: to receive system information corresponding to the first carrier and to search for another first carrier (first embodiment).

[0394] The transmitting / receiving unit 120 may transmit a synchronization signal on a first carrier common to multiple terminals detected by monitors of multiple frequencies. The control unit 110 may use the synchronization signal to instruct at least one of the following: receiving first system information corresponding to the first carrier, searching for a second carrier specific to its own terminal corresponding to the first carrier, and searching for another first carrier (second embodiment).

[0395] (User Terminal) Figure 9 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.

[0396] 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.

[0397] 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.

[0398] 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.

[0399] 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.

[0400] 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.

[0401] 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.

[0402] 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.

[0403] 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.

[0404] 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.

[0405] 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.

[0406] 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.

[0407] 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.

[0408] 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.

[0409] 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.

[0410] 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.

[0411] 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.

[0412] 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.

[0413] The transmitting / receiving unit 220 may monitor multiple frequencies, detect a first carrier common to multiple terminals, and receive a synchronization signal transmitted on the first carrier. The control unit 210 may control, based on the synchronization signal, the reception of system information corresponding to the first carrier and the search for another first carrier, or at least one of the latter (first embodiment).

[0414] The control unit 210 may control at least one of the following based on the system information: searching for another first carrier and determining a suitable cell (first embodiment).

[0415] The system information may be transmitted on a second carrier specific to the terminal that corresponds to the first carrier (first embodiment).

[0416] The band corresponding to the first carrier may be a different band from the Time Division Duplex (TDD) band, the Frequency Division Duplex (FDD) band, and the supplementary uplink band (first embodiment).

[0417] The transmitting / receiving unit 220 may monitor multiple frequencies, detect a first carrier common to multiple terminals, and receive a synchronization signal transmitted on the first carrier. Based on the synchronization signal, the control unit 210 may control at least one of the following: receiving first system information corresponding to the first carrier, searching for a second carrier specific to its own terminal corresponding to the first carrier, and searching for another first carrier (second embodiment).

[0418] The control unit 210 may control at least one of the search for the second carrier and the search for another first carrier based on the first system information.

[0419] The control unit 210 may control at least one of the following based on a synchronization signal transmitted on the second carrier: receiving first system information corresponding to the first carrier, searching for another first carrier, and searching for another second carrier (second embodiment).

[0420] The transmitting / receiving unit 220 may receive information regarding the synchronization signal transmitted on at least one of the other first carrier and the second carrier based on the synchronization signal transmitted on the first carrier (third embodiment).

[0421] (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.

[0422] 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.

[0423] 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 10 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.

[0424] 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.

[0425] 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.

[0426] 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.

[0427] 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.

[0428] 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.

[0429] 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.

[0430] 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.

[0431] 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).

[0432] 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).

[0433] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0434] 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.

[0435] 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.

[0436] (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.

[0437] 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.

[0438] 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.

[0439] 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.

[0440] 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.

[0441] 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.

[0442] 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.

[0443] 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.

[0444] 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.

[0445] In addition, when one slot or one mini-slot is called a TTI, one or more TTIs (i.e., one or more slots or one or more mini-slots) may be the minimum time unit for scheduling. Also, the number of slots (number of mini-slots) constituting the minimum time unit for the scheduling may be controlled.

[0446] A TTI having a time length of 1 ms may be called a normal TTI (TTI in 3GPP Rel. 8 - 12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial TTI (partial or fractional TTI), a shortened subframe, a short subframe, a mini-slot, a sub-slot, a slot, etc.

[0447] Note that a long TTI (e.g., a normal TTI, a subframe, etc.) may be read as a TTI having a time length exceeding 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be read as a TTI having a TTI length less than that of a long TTI and not less than 1 ms.

[0448] A resource block (Resource Block (RB)) is a resource allocation unit in the time domain and the frequency domain, and in the frequency domain, it may include one or a plurality of consecutive subcarriers (subcarriers). The number of subcarriers included in an RB may be the same regardless of the numerology, and may be, for example, 12. The number of subcarriers included in an RB may be determined based on the numerology.

[0449] Also, an RB may include one or a plurality of symbols in the time domain, and may have a length of one slot, one mini-slot, one subframe, or one TTI. One TTI, one subframe, etc. may each be constituted by one or a plurality of resource blocks.

[0450] Note that one or more RBs may be referred to as a physical resource block (Physical RB (PRB)), a sub-carrier group (Sub-Carrier Group (SCG)), a resource element group (Resource Element Group (REG)), a PRB pair, an RB pair, etc.

[0451] Also, a resource block may be composed of one or more resource elements (Resource Element (RE)). For example, 1 RE may be a radio resource region of 1 sub-carrier and 1 symbol.

[0452] A bandwidth part (Bandwidth Part (BWP)) (which may also be referred to as a partial bandwidth, etc.) may represent a subset of consecutive common resource blocks (common resource blocks) for a certain numerology in a certain carrier. Here, the common RB may be specified by the index of the RB based on the common reference point of the carrier. The PRB is defined in a certain BWP and may be numbered within the BWP.

[0453] The BWP may include a UL BWP (BWP for UL) and a DL BWP (BWP for DL). For a UE, one or more BWPs may be set within one carrier.

[0454] At least one of the set BWPs may be active, and the UE may not be assumed to transmit and receive a predetermined signal / channel outside the active BWP. Note that "cell", "carrier", etc. in the present disclosure may be read as "BWP".

[0455] 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.

[0456] 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.

[0457] 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.

[0458] 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.

[0459] 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.

[0460] 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.

[0461] 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.

[0462] 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.

[0463] 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).

[0464] 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).

[0465] 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).

[0466] 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.

[0467] 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.

[0468] 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).

[0469] 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.

[0470] 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.

[0471] 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.

[0472] 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.

[0473] 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.

[0474] 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.

[0475] 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.

[0476] 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.

[0477] 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.

[0478] 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.

[0479] 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.

[0480] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0481] 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.

[0482] 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.

[0483] The moving body refers to an object that can move, and its moving speed is arbitrary, including the case where the moving body is stopped. The moving body includes, for example, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, shovel cars, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, rear cars, rickshaws, ships (ships and other watercraft), airplanes, rockets, artificial satellites, drones, multicopters, quadcopters, balloons, and objects mounted on these, and is not limited thereto. Further, the moving body may be a moving body that autonomously travels based on an operation command.

[0484] The moving body may be a vehicle (e.g., a car, an airplane, etc.), a moving body that moves without a driver (e.g., a drone, an autonomous driving vehicle, etc.), or a robot (a manned or unmanned type). Note that at least one of the base station and the mobile station includes a device that does not necessarily move during communication operation. 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.

[0485] FIG. 11 is a diagram showing an example of a vehicle according to an embodiment. The vehicle 40 includes a drive unit 41, a steering unit 42, an accelerator pedal 43, a brake pedal 44, a shift lever 45, left and right front wheels 46, left and right rear wheels 47, 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.

[0486] The drive unit 41 is composed of, for example, at least one of an engine, a motor, and a hybrid of an engine and a motor. The steering unit 42 includes at least a steering wheel (also called a steering handle), and is configured to steer at least one of the front wheels 46 and the rear wheels 47 based on an operation of the steering wheel operated by a user.

[0487] 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).

[0488] 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.

[0489] 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.

[0490] 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.).

[0491] 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.

[0492] 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.

[0493] 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).

[0494] 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.

[0495] 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).

[0496] 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.

[0497] 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.

[0498] 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.

[0499] 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.

[0500] 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.

[0501] 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).

[0502] 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."

[0503] 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.

[0504] 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.

[0505] 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).

[0506] 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.

[0507] 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….”

[0508] 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).

[0509] 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.

[0510] 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.”

[0511] 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.

[0512] 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."

[0513] 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.

[0514] 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.

[0515] 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").

[0516] In this disclosure, "of," "for," "regarding," "related to," and "associated with" may be interpreted as being interchangeable.

[0517] 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.

[0518] 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.

[0519] 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 monitors multiple frequencies, detects a first carrier common to multiple terminals, and receives a synchronization signal transmitted on the first carrier; and a control unit that controls, based on the synchronization signal, receiving system information corresponding to the first carrier, searching for another first carrier, and controlling at least one of the above.

2. The terminal according to claim 1, wherein the control unit controls at least one of searching for another first carrier and determining a suitable cell based on the system information.

3. The terminal according to claim 1, wherein the system information is transmitted on a second carrier specific to the terminal that corresponds to the first carrier.

4. The terminal according to claim 1, wherein the band corresponding to the first carrier is a different band from the Time Division Duplex (TDD) band, the Frequency Division Duplex (FDD) band, and the supplementary uplink band.

5. A wireless communication method for a terminal, comprising the steps of: monitoring multiple frequencies, detecting a first carrier common to multiple terminals, and receiving a synchronization signal transmitted on the first carrier; and, based on the synchronization signal, receiving system information corresponding to the first carrier, searching for another first carrier, and controlling at least one of the two.

6. A base station having: a transmitting unit that transmits a synchronization signal on a first carrier common to multiple terminals detected by monitors of multiple frequencies; and a control unit that uses the synchronization signal to receive system information corresponding to the first carrier, search for another first carrier, and instruct at least one of the above.

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