Terminal, wireless communication method and base station

Abstract

A terminal according to one embodiment of the present disclosure has: a reception unit for receiving settings for two physical downlink control channel (PDCCH) candidates which are mutually linked; and a control unit for, when joint hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback is set, determining a HARQ-ACK codebook by using, as effective HARQ-ACK information, a HARQ-ACK which corresponds to a reference PDCCH candidate from among the two PDCCH candidates. According to the one embodiment of the present disclosure, repeated PDCCH transmission can be appropriately handled.

Description

[Technical Field]

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

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

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

[0004] [Non-Patent Document 1] 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 Summary of the Invention [Problem to be solved by the invention]

[0005] For future wireless communication systems, repetition of the Physical Downlink Control Channel (PDCCH) is being considered.

[0006] However, there has been little research into how to provide Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback corresponding to PDCCH repetition (e.g., the contents of the HARQ-ACK codebook, resources for transmitting HARQ-ACK).

[0007] Unless these are clearly defined, HARQ-ACK feedback cannot be performed appropriately when PDCCH repetitive transmission is used, which may result in a decrease in throughput or degradation of communication quality.

[0008] Therefore, one object of the present disclosure is to provide a terminal, a radio communication method, and a base station that can appropriately handle PDCCH repeated transmission. [Means for solving the problem]

[0009] A terminal according to one aspect of the present disclosure includes: a receiving unit that receives configurations for two Physical Downlink Control Channel (PDCCH) candidates linked to each other; Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) for the downlink shared channel (Physical Downlink Shared Channel (PDSCH)) received from multiple transmission / reception points (Transmission / Reception Points (TRPs)) is transmitted collectively using the same uplink channel resources. Join ToH ARQ-AC KF and a control unit that, when feedback is configured, determines a HARQ-ACK codebook using a HARQ-ACK corresponding to a reference PDCCH candidate of the two PDCCH candidates as valid HARQ-ACK information. [Effects of the Invention]

[0010] According to one aspect of the present disclosure, it is possible to appropriately handle PDCCH repeated transmission. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example in which two linked CORESETs are provided using different CORESET pool indices. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a HARQ-ACK codebook transmitted in the PUCCH of FIG. [Figure 3] FIG. 3 is a diagram illustrating an example of the contents of the HARQ-ACK codebook in the second embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the contents of the HARQ-ACK codebook in the second embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of the contents of the HARQ-ACK codebook in the second embodiment. [Figure 6] FIG. 6 illustrates the DAI problem when two linked CORESETs are provided with different CORESET pool indices. [Figure 7] FIG. 7 is a diagram showing an example of numbering of DAIs in the third embodiment. [Figure 8] FIG. 8 illustrates the problem of determining the final DCI when two linked CORESETs are provided with different CORESET pool indices. [Figure 9] FIG. 9 is a diagram showing an example of determining the final DCI format in the fourth embodiment. [Figure 10] FIG. 10 is a diagram showing an example of determining the final DCI format in the fourth embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of the configuration of a base station according to an embodiment. [Figure 13]FIG. 13 is a diagram illustrating an example of the configuration of a user terminal according to an embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

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

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

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

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

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

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

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

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

[0021] In the present disclosure, the higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, and the like, or a combination thereof.

[0022] The MAC signaling may use, for example, a MAC Control Element (MAC CE), a MAC Protocol Data Unit (PDU), etc. The broadcast information may be, for example, a Master Information Block (MIB), a System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

[0023] The physical layer signaling may be, for example, Downlink Control Information (DCI).

[0024] The channel / signal to which the TCI state is applied may be called a target channel / reference signal (target channel / RS), or simply a target, and the other signal may be called a reference reference signal (reference RS), source RS, or simply a reference.

[0025] The channel for which the TCI state or spatial relationship is set (specified) may be, for example, at least one of a downlink shared channel (Physical Downlink Shared Channel (PDSCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), an uplink shared channel (Physical Uplink Shared Channel (PUSCH)), and an uplink control channel (Physical Uplink Control Channel (PUCCH)).

[0026] Furthermore, the RS that has a QCL relationship with the channel may be at least one of, for example, a Synchronization Signal Block (SSB), a Channel State Information Reference Signal (CSI-RS), a Sounding Reference Signal (SRS), a CSI-RS for tracking (also called a Tracking Reference Signal (TRS)), a QCL detection reference signal (also called a QRS), and a Demodulation Reference Signal (DMRS).

[0027] An SSB is a signal block that includes at least one of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). An SSB may also be referred to as an SS / PBCH block.

[0028] An RS of QCL type X in a TCI state may refer to an RS that has a relationship of QCL type X with (the DMRS of) a certain channel / signal, and this RS may be called a QCL source of QCL type X in the TCI state.

[0029] (Multi-TRP) In NR, it is considered that one or more Transmission / Reception Points (TRPs) (Multi-TRPs (MTRPs)) perform DL transmission to a UE, and it is also considered that a UE performs UL transmission to one or more TRPs.

[0030] If a UE is provided with no CORESET pool index (higher layer parameter CORESETPoolIndex) or a CORESET pool index value = 0 for one or more first CORESETs and a CORESET pool index value = 1 for one or more second CORESETs in the active downlink Bandwidth Part (BWP) of a serving cell, it may be assumed that Multi-DCI based Multi-TRP is used (control based on Multi-DCI based Multi-TRP is performed).

[0031] In Rel. 17 and later, it is assumed that PDCCH repetition is applied to PDCCHs (or DCIs) transmitted from one or more TRPs. For example, it is conceivable that multiple PDCCHs (or DCIs) transmitted from one or more TRPs are used to schedule or instruct transmission / reception of one or more signals / channels.

[0032] The PDCCH / DCI to which repeated transmission is applied may be referred to as a multi-PDCCH / multi-DCI / multi-TRP PDCCH. Repeated transmission of PDCCH may be interchangeably referred to as PDCCH repetition, multiple transmission of PDCCH, multi-PDCCH transmission, multi-TRP PDCCH repetition, MTRP PDCCH, etc.

[0033] Multiple PDCCHs / multiple DCIs may be transmitted from different TRPs (i.e., CORESETs corresponding to different CORESET pool indices), and the multiple PDCCHs / DCIs may be multiplexed using time division multiplexing (TDM), frequency division multiplexing (FDM), or space division multiplexing (SDM).

[0034] For example, when PDCCH repetition is performed using TDM (TDM PDCCH repetition), PDCCHs may be transmitted from multiple TRPs using different time resources.

[0035] In the case of FDM PDCCH repetition, PDCCHs may be transmitted from multiple TRPs using different frequency-time resources. In the FDM PDCCH repetition, at least one of the following may be associated with different TCI states: two sets of resource element groups (REGs), two sets of control channel elements (CCEs) of the transmitted PDCCH, two non-overlapping transmitted PDCCH repetitions in frequency, and two non-overlapping multi-chance transmitted PDCCHs in frequency.

[0036] When SDM PDCCH repetition is performed, PDCCHs may be transmitted from multiple TRPs using the same time / frequency resources. In SDM PDCCH repetition, PDCCH DMRSs in all REGs / CCEs of the PDCCH may be associated with two TCI states. In this disclosure, SDM may be interchangeably read as single frequency network (SFN).

[0037] For NR Rel. 17 and later, the following control is being considered for the reliability of non-SFN based multi-TRP PDCCH: The coding / rate matching is based on one repetition, where the same coded bits are repeated in other repetitions, each of which has the same number of Control Channel Elements (CCEs), the same number of coded bits, and corresponds to the same DCI payload. Two or more PDCCH candidates are explicitly linked together. The UE knows the link before decoding. To realize PDCCH transmission with two TCI states, two Search Space (SS) sets are associated with the two CORESETs, respectively.

[0038] Here, the two or more PDCCH candidates are included in two SS sets (two CORESETs).

[0039] Note that the linking (association) of two SS sets may be configured / activated / notified to the UE by higher layer signaling. When PDCCH repetitions are monitored in two linked SS sets, the UE does not expect that a further (third) monitored SS set is linked to at least one of these two linked SS sets.

[0040] The two linked SS sets may have the same SS set type (eg, common SS, UE-specific SS) and may be configured to monitor the same DCI format.

[0041] For intra-slot PDCCH repetition, the two linked SS sets may have the same period and offset and the same duration. The linked monitoring opportunities across the two SS sets may reside in the same slot. Within a slot, the two sets may have the same number of monitoring opportunities, and the nth (n is an integer) monitoring opportunity of one SS set may be linked with the nth monitoring opportunity of the other SS set.

[0042] Two PDCCH candidates in two SS sets may be linked based on having the same aggregation level (AL) and the same candidate index, and the two linked SS sets may be configured to have the same number of PDCCH candidates for each AL.

[0043] (Multi-TRP HARQ-ACK) Separate HARQ-ACK feedback and joint HARQ-ACK feedback are being considered as Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback for multi-PDSCH. In this disclosure, "separate" may be interchangeably read as "independent."

[0044] Separate HARQ-ACK feedback (also referred to as separate feedback or separate HARQ-ACK) corresponds to feedback in which a UE transmits HARQ-ACK for each TRP on separate uplink control channel (Physical Uplink Control Channel (PUCCH)) / uplink shared channel (Physical Uplink Shared Channel (PUSCH)) resources. The multiple PUCCH / PUSCH resources may overlap (be transmitted simultaneously) or may not overlap (e.g., be TDM / FDM).

[0045] Separate HARQ-ACK allows independent HARQ-ACK transmission for each TRP, so the HARQ delay is not large even when the backhaul delay between TRPs is large (for example, when the TRPs are connected via a non-ideal backhaul).

[0046] Joint HARQ-ACK feedback (which may also be referred to as joint feedback, joint HARQ-ACK, etc.) corresponds to feedback in which a UE collectively transmits HARQ-ACKs for multiple TRPs on the same PUCCH / PUSCH resource.

[0047] Using joint HARQ-ACK reduces resource overhead because only one PUCCH / PUSCH transmission is required. Also, if the backhaul delay between TRPs is small (e.g., the TRPs are connected via an ideal backhaul), the HARQ-ACK sent to one TRP can be delivered to the other TRP with low latency.

[0048] In Rel. 16 NR, the UE may configure the feedback mode using a higher layer parameter (which may be called "ackNackFeedbackMode", "ackNackFeedbackMode-r16", ACKNACK feedback mode, etc.) that indicates whether the feedback mode used within one slot is joint feedback or separate feedback.

[0049] One or more DCIs scheduling multiple PDSCHs may include a PUCCH resource indicator (PRI) field. The PRI corresponds to information specifying a resource for transmitting a HARQ-ACK corresponding to a PDSCH, and may also be called an ACK / NACK resource indicator (ARI).

[0050] The UE may determine, based on the PRI, a PUCCH resource for transmitting a HARQ-ACK corresponding to the multi-PDSCH.

[0051] (HARQ-ACK codebook) In NR, a UE may transmit HARQ-ACK feedback using one PUCCH resource for each HARQ-ACK codebook consisting of one or more acknowledgement information bits (e.g., Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK)). HARQ-ACK bits may also be referred to as HARQ-ACK information, HARQ-ACK information bits, etc.

[0052] Here, the HARQ-ACK codebook may be configured to include bits for HARQ-ACK in at least one unit of the time domain (e.g., slot), the frequency domain (e.g., component carrier (CC)), the spatial domain (e.g., layer), the transport block (TB), and the code block group (CBG) constituting the TB. The HARQ-ACK codebook may be simply referred to as a codebook.

[0053] The number of bits (size) included in the HARQ-ACK codebook may be determined semi-statically or dynamically. An HARQ-ACK codebook whose size is determined semi-statically is also called a semi-static HARQ-ACK codebook, a type 1 HARQ-ACK codebook, etc. An HARQ-ACK codebook whose size is determined dynamically is also called a dynamic HARQ-ACK codebook, a type 2 HARQ-ACK codebook, etc.

[0054] Whether to use the Type 1 HARQ-ACK codebook or the Type 2 HARQ-ACK codebook may be configured in the UE using a higher layer parameter (for example, pdsch-HARQ-ACK-Codebook).

[0055] In the case of a Type 1 HARQ-ACK codebook, the UE may feed back HARQ-ACK bits for PDSCH candidates (or PDSCH opportunities) corresponding to a certain range (e.g., a range set based on higher layer parameters), regardless of whether PDSCH is scheduled or not.

[0056] The range may be determined based on at least one of a time period (e.g., a set of a certain number of candidate occasions for PDSCH reception or a certain number of PDCCH monitoring occasions), the number of CCs configured or activated in the UE, the number of TBs (number of layers or ranks), the number of CBGs per TB, and whether spatial bundling is applied. The range may also be called a HARQ-ACK window, a HARQ-ACK bundling window, a HARQ-ACK feedback window, etc.

[0057] In the type 1 HARQ-ACK codebook, even if a PDSCH is not scheduled for the UE, the UE reserves a bit for the PDSCH in the codebook as long as it is within the above range. If the UE determines that the PDSCH is not actually scheduled, it can feed back the bit as a NACK bit.

[0058] Meanwhile, in the case of a Type 2 HARQ-ACK codebook, the UE may feed back HARQ-ACK bits for the scheduled PDSCH within the above range.

[0059] Specifically, the UE may determine the number of bits of the Type 2 HARQ-ACK codebook based on a field in the DCI (e.g., a Downlink Assignment Indicator (Index) (DAI) field). The DAI field may include a Counter DAI (C-DAI) and a Total DAI (T-DAI).

[0060] The C-DAI may indicate a counter value of downlink transmissions (PDSCH, data, TB) scheduled within a certain period. For example, the C-DAI in a DCI that schedules data within the period may indicate the number counted first in the frequency domain (e.g., CC) and then in the time domain within the period. For example, the C-DAI may correspond to a value obtained by counting PDSCH receptions or Semi-Persistent Scheduling (SPS) releases for one or more DCIs included in the period, in ascending order of serving cell index, and then in ascending order of PDCCH monitoring opportunities.

[0061] That is, C-DAI may refer to the cumulative number of pairs of {serving cell, PDCCH monitoring occasion} corresponding to each data up to the current serving cell and the current PDCCH monitoring occasion.

[0062] The T-DAI may indicate the total number of data scheduled within a certain period of time. For example, the T-DAI in a DCI that schedules data at a certain time unit (e.g., a PDCCH monitoring opportunity) within the period of time may indicate the total number of data scheduled up to that time unit (also referred to as a point, timing, etc.) within the period of time.

[0063] In other words, T-DAI may refer to the total number of pairs of {serving cell, PDCCH monitoring opportunity} corresponding to each data up to the current PDCCH monitoring opportunity, and may be a value that is updated for each PDCCH monitoring opportunity.

[0064] Incidentally, in the Rel. 16 NR that has been considered so far, CORESETs with different CORESET pool indices are used to schedule different PDSCHs (multi-DCI-based multi-TRP).

[0065] For this reason, Rel. 16 NR specifies that when the above-mentioned first and second CORESETs are configured in a UE and joint feedback is configured ("ackNackFeedbackMode-r16"="joint" is set), the UE transmits HARQ-ACK information related to the first CORESET and HARQ-ACK information related to the second CORESET together for the Type 1 and Type 2 HARQ-ACK codebooks using a single PUCCH resource.

[0066] In the present disclosure, the terms "first TRP," "TRP1," "first CORESET," and "CORESET for which no CORESET pool index is provided or for which a CORESET pool index value = 0 is provided" may be interchangeable. Also, "first CORESET" may mean one or more first CORESETs.

[0067] In the present disclosure, the terms "second TRP," "TRP2," "second CORESET," and "CORESET to which a CORESET pool index value = 1 is provided" may be interchangeable. Also, "second CORESET" may mean one or more second CORESETs.

[0068] Meanwhile, the two CORESETs associated with the two linked SS sets (also referred to as "two linked CORESETs for PDCCH repetition" in this disclosure) are used for repeated transmission of the same DCI payload. In other words, the two linked CORESETs may be used to schedule the same PDSCH.

[0069] Therefore, there is a problem of which TRP the HARQ-ACK for the PDSCH scheduled in the two linked CORESETs is intended for. That is, when two linked CORESETs are provided using different CORESET pool indices for PDCCH repetition, it has not yet been studied what kind of HARQ-ACK should be generated for the PDSCH scheduled by DCI transmitted in two linked PDCCH candidates in the two linked CORESETs, and on which resource the HARQ-ACK should be transmitted.

[0070] Unless these are clearly defined, HARQ-ACK feedback cannot be performed appropriately when using multi-TRP PDCCH repetition transmission, which may result in a decrease in throughput or degradation of communication quality.

[0071] Therefore, the present inventors have conceived a method for performing uplink (for example, PUCCH / PUSCH) transmission in a suitable manner for PDCCH repeated transmission.

[0072] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. Wireless communication methods according to the embodiments may be applied independently or in combination.

[0073] In the present disclosure, "A / B" may also mean "at least one of A and B."

[0074] In the present disclosure, the terms activate, deactivate, indicate, select, configure, update, determine, etc. may be read interchangeably.

[0075] In the present disclosure, RRC, RRC parameter, RRC message, higher layer parameter, information element (IE), and configuration may be interchangeable. In the present disclosure, MAC CE, update command, and activation / deactivation command may be interchangeable. In the present disclosure, support, control, controllable, operate, and operable may be interchangeable.

[0076] Additionally, in the present disclosure, the terms sequence, list, set, group, and group may be read interchangeably.

[0077] In the present disclosure, terms such as panel, beam, panel group, beam group, Uplink (UL) transmitting entity, TRP, spatial relationship information (SRI), spatial relationship, control resource set (CORESET), Physical Downlink Shared Channel (PDSCH), codeword, base station, predetermined antenna port (e.g., Demodulation Reference Signal (DMRS) port), predetermined antenna port group (e.g., DMRS port group), predetermined group (e.g., Code Division Multiplexing (CDM) group, predetermined reference signal group, CORESET group), predetermined resource (e.g., predetermined reference signal resource), predetermined resource set (e.g., predetermined reference signal resource set), CORESET pool, PUCCH group (PUCCH resource group), spatial relationship group, downlink TCI state (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, etc. may be interpreted as interchangeable.

[0078] The panel may be associated with at least one of a group index of an SSB / CSI-RS group, a group index of a group-based beam report, and a group index of an SSB / CSI-RS group for group-based beam reporting.

[0079] Furthermore, a panel identifier (ID) and a panel may be interchangeable. That is, a TRP ID and a TRP, a CORESET group ID and a CORESET group, etc. may be interchangeable.

[0080] In this disclosure, the terms index, ID, indicator, and resource ID may be interchangeable. In this disclosure, the terms sequence, list, set, group, group, cluster, and subset may be interchangeable.

[0081] In this disclosure, a single PDCCH may be assumed to be supported when multiple TRPs utilize an ideal backhaul, and multiple PDCCHs may be assumed to be supported when multiple TRPs utilize a non-ideal backhaul.

[0082] The ideal backhaul may be called DMRS port group type 1, reference signal associated group type 1, antenna port group type 1, CORESET pool type 1, etc. The non-ideal backhaul may be called DMRS port group type 2, reference signal associated group type 2, antenna port group type 2, CORESET pool type 2, etc. The names are not limited to these.

[0083] In the present disclosure, multi-TRP, multi-TRP system, multi-TRP transmission, and multi-PDSCH may be read as interchangeable.

[0084] In the present disclosure, single DCI (sDCI), single PDCCH, multi-TRP system based on single DCI, sDCI-based MTRP, and activation of two TCI states on at least one TCI codepoint may be read interchangeably.

[0085] In the present disclosure, multi-DCI (mDCI), multi-PDCCH, multi-TRP system based on multi-DCI, mDCI-based MTRP, and setting two CORESET pool indices or CORESET pool index=1 (or a value greater than or equal to 1) may be read interchangeably.

[0086] The QCL of the present disclosure may be interchangeably read as QCL Type D.

[0087] Each embodiment may be applied to a case where Multi-DCI based Multi-TRP is used.

[0088] Each embodiment is described assuming that a CORESET pool index (upper layer parameter CORESETPoolIndex) is not provided for one or more first CORESETs or a CORESET pool index value = 0 is provided, and a CORESET pool index value = 1 is provided for one or more second CORESETs, and joint feedback is set (for example, "ackNackFeedbackMode-r16" = "joint" is set), but is not limited to this.

[0089] (Wireless communication method) First Embodiment The first embodiment relates to whether two linked CORESETs for PDCCH repetition are provided using different CORESET pool indices when joint feedback is configured (e.g., "ackNackFeedbackMode-r16"="joint" is set).

[0090] The first embodiment is broadly divided into the following two types: (Embodiment 1.1) The UE does not expect that two linked CORESETs for PDCCH repetition are provided with different CORESET pool indices. (Embodiment 1.2) The UE may expect two linked CORESETs for PDCCH repetition to be provided with the same or different CORESET pool indexes.

[0091] In embodiment 1.1, the UE may expect that two linked CORESETs for PDCCH repetition are provided with the same CORESET pool index.

[0092] In embodiment 1.1, if one of two linked CORESETs has a CORESET pool index configured and the other does not, the UE may assume that the two linked CORESETs have the same CORESET pool index configured.

[0093] For embodiment 1.1, the UE may always generate one HARQ-ACK for one TRP for one PDSCH. For embodiment 1.2, whether the UE generates two HARQ-ACKs for two TRPs for one PDSCH scheduled by DCI in two linked PDCCH candidates for PDCCCH repetition will be described in a later embodiment.

[0094] It is to be noted that using the same CORESET pool index for two linked CORESETs is simple and preferable, whereas using different CORESET pool indices for two linked CORESETs is preferable for TRP repetition of PDCCH.

[0095] According to the first embodiment described above, it is possible to appropriately determine how two linked CORESETs for PDCCH repetition are associated with CORESET pool indices.

[0096] <Second embodiment> The second embodiment relates to a Type 1 HARQ-ACK codebook.

[0097] 1 is a diagram showing an example in which two linked CORESETs are provided using different CORESET pool indexes. The second embodiment will be described mainly using FIG. 1 as an example, but those skilled in the art will understand that the application of this embodiment is not limited to this case.

[0098] In this example, the UE is configured with two serving cells (CC0-CC1). The UE is also configured with a first CORESET and a second CORESET so as to operate with multiple TRPs (TRP1, 2) for each cell. It is also assumed that slots 0-3 are DL slots and slot 4 is an UL slot. This also applies to the following drawings unless otherwise noted.

[0099] FIG. 1 shows the transmission timing of the HARQ-ACK for the PDSCH (PDSCH-to-HARQ feedback timing, which may be referred to as K1, etc.). K1 may be specified by the PDSCH-to-HARQ feedback timing indicator field included in the DCI (e.g., DCI format 1_0 / 1_1 / 1_2) that schedules the PDSCH. If the last slot in which the PDSCH was received is n, the UE transmits the HARQ-ACK corresponding to the PDSCH in n+K1 slots.

[0100] The UE may transmit HARQ-ACK for the DCI received in slots 0-3 (for the PDSCH scheduled by that DCI) in slot 4 of CC0. The UE transmits the HARQ-ACK codebook for TRP1 (CORESET pool index = 0) and the HARQ-ACK codebook for TRP2 (CORESET pool index = 1) together in PUCCH #1 of CC0. The dashed lines across the slots indicate the order of the corresponding HARQ-ACK information bits in the HARQ-ACK codebooks (described later in Figure 2).

[0101] The CC that transmits the PUCCH is not limited to CC0 and may be CC1 depending on the settings, etc. The TRP that transmits the PUCCH is not limited to TRP1 and may be TRP2 depending on the settings, etc.

[0102] In this example, the PDSCH scheduled by the DCI is indicated by a dashed line. The UE receives DCI (DCI #1-1, #1-2) that is repeatedly transmitted using a CORESET with a CORESET pool index of 0 (first CORESET) and a CORESET with a CORESET pool index of 1 (second CORESET) in slot 0 of CC0.

[0103] The repeatedly transmitted DCI schedules the same PDSCH (PDSCH#1). Note that in this disclosure, the "same PDSCH" may refer to a PDSCH with the same content, and may be transmitted from a different TRP (using a different beam).

[0104] Figure 2 is a diagram showing an example of the configuration of a HARQ-ACK codebook transmitted in the PUCCH of Figure 1. The HARQ-ACK codebook (which may be referred to as a joint HARQ-ACK codebook) transmitted in PUCCH#1 may be obtained by concatenating the HARQ-ACK codebook for TRP1 (in other words, for the first set of serving cells including the first CORESET) and the HARQ-ACK codebook for TRP2 (in other words, for the second set of serving cells including the second CORESET).

[0105] For the HARQ-ACK codebook for TRP1 and the HARQ-ACK codebook for TRP2, the PDCCH monitoring opportunities included in the corresponding period (slots 0-3 in this example) are first indexed in ascending order of CC index and then in descending order of K1, and the HARQ-ACK bits corresponding to each PDCCH monitoring opportunity are arranged in this order.

[0106] FIG. 2 shows that the 0th to 3rd bits included in the joint HARQ-ACK codebook correspond to K1=4 to K1=1 of CC0 for TRP1, the 4th to 7th bits correspond to K1=4 to K1=1 of CC1 for TRP1, the 8th to 11th bits correspond to K1=4 to K1=1 of CC0 for TRP2, and the 12th to 15th bits correspond to K1=4 to K1=1 of CC1 for TRP2.

[0107] However, in the current standard, it is not clear whether the bits (0th and 8th bits in this example) corresponding to the DCI (CC0 and K1=4) received in the two linked CORESETs in the joint HARQ-ACK codebook of Figure 2 indicate the HARQ-ACK feedback (HARQ-ACK bits) for PDSCH#1. For this reason, the inventors have arrived at a second embodiment.

[0108] In the second embodiment, for a PDSCH scheduled by DCI transmitted on two linked PDCCH candidates in two linked CORESETs having different CORESET pool indices for PDCCH repetition, only HARQ-ACK information corresponding to PDCCH candidates (which may be referred to as referred PDCCH candidate, reference PDCCH candidate, PDCCH candidate taken as reference, etc.) that fall under any one of the following or a combination thereof among the PDCCH candidates of the first CORESET and the PDCCH candidates of the second CORESET may be fed back: (2-0) Both the PDCCH candidates of the first CORESET and the PDCCH candidates of the second CORESET; (2-1) PDCCH candidate of the first CORESET, (2-2) PDCCH candidates of the second CORESET, (2-3) PDCCH candidates with earlier or later PDCCH monitoring opportunities, (2-4) PDCCH candidates of CORESETs with smaller or larger CORESET IDs, (2-5) PDCCH candidates with a smaller or larger CORESET SS set ID, (2-6) PDCCH candidates of a CORESET included in the same CORESET pool index as the CORESET pool index related to the PUCCH resource indicated by the above DCI (however, if an association between a PUCCH resource and a CORESET pool index is configured / specified).

[0109] When multiple of the above (2-0) to (2-6) are supported, which condition applies may be configured / activated / indicated to the UE using higher layer signaling (e.g., RRC signaling, MAC CE), physical layer signaling (e.g., DCI), or a combination thereof. Also, there may be one or more PDCCH candidates for each of the above (2-0) to (2-6).

[0110] In addition, among the DCI transmitted by two linked PDCCH candidates, the HARQ-ACK corresponding to the CORESET pool index of the referenced PDCCH candidate may be expressed as valid HARQ-ACK information, and the HARQ-ACK corresponding to a different CORESET pool index may be expressed as invalid (or invalid) HARQ-ACK information.

[0111] The HARQ-ACK information of the PDSCH may be reported only in the HARQ-ACK codebook for the same CORESET pool index as the CORESET pool index of the referenced PDCCH candidate. The HARQ-ACK information of the PDSCH (valid HARQ-ACK information) may be ACK (e.g., 1) if the PDSCH is successfully decoded, or NACK (e.g., 0) if not.

[0112] In a HARQ-ACK codebook for a CORESET pool index different from the CORESET pool index of the referenced PDCCH candidate, the HARQ-ACK information corresponding to the above DCI (invalid HARQ-ACK information) may be NACK-fixed, ACK-fixed, or may depend on the UE implementation.

[0113] 3 to 5 are diagrams showing examples of the contents of the HARQ-ACK codebook in the second embodiment. Since the contents of the 0th and 8th bits of the joint HARQ-ACK codebook have been described with reference to FIG. 2, the description thereof will not be repeated.

[0114] 3 corresponds to the case according to the above (2-0). The UE includes actual HARQ-ACK information for PDSCH#1 in both the 0th bit of the HARQ-ACK codebook for TRP1 (i.e., the 0th bit of the joint HARQ-ACK codebook) and the 0th bit of the HARQ-ACK codebook for TRP2 (i.e., the 8th bit of the joint HARQ-ACK codebook).

[0115] Figure 4 corresponds to the case according to (2-1) above. The UE includes the actual HARQ-ACK information for PDSCH#1 for the 0th bit of the HARQ-ACK codebook for TRP1, and includes ACK-fixed (or NACK-fixed or information depending on the UE implementation) for the 0th bit of the HARQ-ACK codebook for TRP2.

[0116] Figure 5 corresponds to the case according to (2-2) above. The UE includes the actual HARQ-ACK information for PDSCH#1 for the 0th bit of the HARQ-ACK codebook for TRP2, and includes ACK-fixed (or NACK-fixed or information depending on the UE implementation) for the 0th bit of the HARQ-ACK codebook for TRP1.

[0117] According to the second embodiment described above, when two linked CORESETs are used for PDCCH repetition, the UE can generate an appropriate Type 1 HARQ-ACK codebook.

[0118] <Third embodiment> The third embodiment relates to a Type 2 HARQ-ACK codebook.

[0119] 6 is a diagram showing the problem of DAI when two linked CORESETs are provided using different CORESET pool indexes. The explanation may be omitted in the same manner as in FIG. 1.

[0120] In this example, the UE detects DCI (DCI #1-1, #1-2) that is repeatedly transmitted using a CORESET (first CORESET) with CORESET pool index = 0 and a CORESET (second CORESET) with CORESET pool index = 1 in slot 0 of CC0.

[0121] Furthermore, the UE detects normal (non-repeated transmission) DCI#2 in slot 0 of CC1 of the first CORESET.

[0122] Furthermore, the UE detects normal (non-repeated transmission) DCI#2' in slot 0 of CC1 of the second CORESET.

[0123] In the current Rel.16 NR standard, it is unclear what value the DAI (C-DAI, T-DAI) should be for repeated DCIs transmitted in two linked CORESETs corresponding to different CORESET pool indices. In other words, the contents (payload) of repeated DCIs (also called two repeated DCIs) transmitted in two linked CORESETs are the same (the DAI is also the same value), but it is unclear whether the DAI of the repeated DCI is the value for TRP1 or TRP2.

[0124] Furthermore, since the DAI corresponds to a value obtained by counting DCIs in ascending order of serving cell index, and then in ascending order of PDCCH monitoring opportunities, it is unclear how to handle repeated DCIs. Therefore, it is not possible to specify the C-DAI and T-DAI for each DCI shown in the figure (indicated by "?"). For this reason, the inventors have arrived at a third embodiment.

[0125] In the third embodiment, for PDCCH repetition, DCI transmitted in two linked PDCCH candidates in two linked CORESETs having different CORESET pool indices may be configured to indicate (and the UE may assume to indicate) a DAI (C-DAI, T-DAI) corresponding to one of the following PDCCH candidates or a combination thereof (which may be referred to as a referred PDCCH candidate, a reference PDCCH candidate, a PDCCH candidate taken as reference, etc.) among the PDCCH candidates of the first CORESET and the PDCCH candidates of the second CORESET: (3-1) PDCCH candidate of the first CORESET, (3-2) PDCCH candidates of the second CORESET, (3-3) PDCCH candidates with earlier or later PDCCH monitoring opportunities, (3-4) PDCCH candidates of CORESETs with smaller or larger CORESET IDs, (3-5) PDCCH candidates with a smaller or larger CORESET SS set ID, (3-6) PDCCH candidates of a CORESET included in the same CORESET pool index as the CORESET pool index related to the PUCCH resource indicated by the above DCI (however, if an association between a PUCCH resource and a CORESET pool index is configured / specified).

[0126] When multiple of the above (3-1) to (3-6) are supported, which condition applies may be configured / activated / indicated to the UE using higher layer signaling (e.g., RRC signaling, MAC CE), physical layer signaling (e.g., DCI), or a combination thereof. Also, there may be one or more PDCCH candidates for each of the above (3-1) to (3-6).

[0127] In the existing Rel.16 NR, when joint HARQ-ACK feedback is configured, the C-DAI values ​​are counted in the order of the first CORESET and the second CORESET for the same serving cell index and the same PDCCH monitoring opportunity. Also, in the existing Rel.16 NR, when joint HARQ-ACK feedback is configured, the T-DAI value corresponds to the total number of {serving cell, PDCCH monitoring opportunity} pairs in both the first CORESET and the second CORESET.

[0128] On the other hand, in the third embodiment, the DAI included in two (same) repeated DCIs is determined to indicate a DAI value derived assuming the CORESET pool index (first / second CORESET) to which the reference PDCCH candidate belongs. In other words, the repeated DCI may be taken into account (may be counted) for the C-DAI and T-DAI in the DCI with the same CORESET pool index as the reference PDCCH candidate. The repeated DCI may be ignored (may not be counted) for the C-DAI and T-DAI in the DCI with a CORESET pool index different from that of the reference PDCCH candidate. For example, in the case of (3-1) above, since the DAI of the repeated DCI indicates the DAI value assuming the first CORESET, the UE may assume that the DAI of DCI#1-1 in Figure 6 received on the PDCCH corresponding to the first CORESET is a correct (or valid) value and use it to determine the number of HARQ-ACK bits, but may assume that the DAI of DCI#1-2 received on the PDCCH corresponding to the second CORESET is an incorrect (or invalid) value and not use it to determine the number of HARQ-ACK bits.

[0129] Note that counting the DAI based on at least one of the above (3-1) to (3-6) may be applied when the two linked PDCCH candidates belong to the same PDCCH monitoring occasion, or when they belong to different PDCCH monitoring occasions. Also, the method of counting the DAI based on at least one of the above (3-1) to (3-6) may be different depending on whether the two linked PDCCH candidates belong to the same PDCCH monitoring occasion or different PDCCH monitoring occasions.

[0130] 7 is a diagram showing an example of numbering of DAIs in the third embodiment. The same as in FIG. 6, the points where description is omitted may be omitted.

[0131] Note that the value of DAI is usually expressed by applying modulo arithmetic (expressed as the remainder when the original value is divided by a predetermined number (e.g., 4) (i.e., the original value mod the predetermined number)). However, in the examples of the present disclosure, for ease of understanding, the value is expressed without applying modulo arithmetic.

[0132] 7 corresponds to the case according to (3-1) or (3-2) above. In slot 0, there are a total of four DCIs in TRP1 and 2, but the repeated DCIs DCI#1-1 and DCI#1-2 are counted only once in the T-DAI, so the T-DAI indicated by each DCI is 3.

[0133] On the other hand, if DCI#1-2 are not counted, the C-DAI of DCI#1-1 (#1-2) is 1, the C-DAI of DCI#2 is 2, and the C-DAI of DCI#2' is 3.

[0134] In the description of the third embodiment, only the DCI indicating both C-DAI and T-DAI (for example, DCI format 1_1 / 1_2) is included, but this is not limiting. The third embodiment is applicable to the case where at least one of the DCI indicating both C-DAI and T-DAI and the DCI indicating only C-DAI (for example, DCI format 1_0) is used.

[0135] According to the third embodiment described above, when two linked CORESETs are used for PDCCH repetition, the UE can generate an appropriate Type 2 HARQ-ACK codebook.

[0136] <Fourth embodiment> A fourth embodiment relates to determining PUCCH resources for transmitting joint HARQ-ACK feedback.

[0137] The current Rel.15 / 16 NR standard specifies that the PUCCH resource for transmitting HARQ-ACK in a certain slot is determined based on the PRI included in the last DCI format (hereinafter also referred to as the last DCI) among DCI formats (e.g., DCI formats 1_0 / 1_1 / 1_2) having a value in the PDSCH-to-HARQ feedback timing indicator field indicating PUCCH transmission in that slot.

[0138] More specifically, in the current Rel.15 / 16 NR standard, the PUCCH resource determination is based on one PUCCH resource indicator field (if present), which has a value indicating the same slot for PUCCH transmission and is included in the last DCI format detected by the UE and in which the UE transmits corresponding HARQ-ACK information on the PUCCH.

[0139] The value indicating the same slot may be the value of the PDSCH-to-HARQ feedback timing indicator field (PDSCH-to-HARQ_feedback timing indicator field, if present), or the value of the higher layer parameter indicating the period from DL data to UL-ACK (dl-DataToUL-ACK), or the value of the higher layer parameter indicating the period from DL data to UL-ACK for DCI format 1_2 (dl-DataToUL-ACKForDCIFormat1_2).

[0140] In the current Rel.15 / 16 NR standard, for PUCCH resource determination, detected DCI formats are first indexed in an ascending order across serving cells indexes for a same PDCCH monitoring occasion and then indexed in an ascending order across PDCCH monitoring occasion indexes. The "last DCI format" above refers to the last DCI format (corresponding to the highest index) indexed according to this rule among the detected DCI formats corresponding to PUCCH transmission in the same slot.

[0141] In addition, in the current specification of Rel. 16, for joint HARQ-ACK feedback, when indexing the DCI formats of one serving cell in the same PDCCH monitoring occasion, the DCI of the first CORESET is indexed before the DCI of the second CORESET.

[0142] 8 is a diagram illustrating a problem of determining the final DCI when two linked CORESETs are provided using different CORESET pool indexes. The omission of the description may be the same as in FIG. 6.

[0143] In this example, the UE detects normal (non-repeated) DCI#1 in slot 0 of CC0 of the first CORESET.

[0144] Furthermore, the UE detects normal (non-repeated transmission) DCI#1' in slot 0 of CC0 of the second CORESET.

[0145] In addition, the UE detects DCI (DCI#2-1, #2-2) that is repeatedly transmitted using a CORESET (first CORESET) with a CORESET pool index = 0 and a CORESET (second CORESET) with a CORESET pool index = 1 in slot 0 of CC1.

[0146] In the current standard, when determining the "last DCI format," it is unclear how to handle a repeat DCI transmitted in two linked CORESETs corresponding to different CORESET pool indices. In other words, it is unclear whether a repeat DCI can be the "last DCI format." Therefore, it is not possible to specify whether the illustrated DCIs #2-1 and #2-2 correspond to the "last DCI" for TRP1 and TRP2, respectively (indicated by "?"). For this reason, the inventors have arrived at the fourth embodiment.

[0147] In the fourth embodiment, for DCI transmitted in two linked PDCCH candidates in two linked CORESETs having different CORESET pool indices for PDCCH repetition, if the PDCCH candidate of the first CORESET and the PDCCH candidate of the second CORESET corresponds to any one of the following or a combination thereof (which may also be referred to as a referred PDCCH candidate, a reference PDCCH candidate, a PDCCH candidate taken as reference, or the like), they may be used as the “last DCI format” for PUCCH resource determination: (4-0) PDCCH candidate of the first CORESET / PDCCH candidate of the second CORESET, (4-1) PDCCH candidate of the first CORESET, (4-2) PDCCH candidates of the second CORESET, (4-3) PDCCH candidates with earlier or later PDCCH monitoring opportunities, (4-4) PDCCH candidates of CORESETs with smaller or larger CORESET IDs, (4-5) PDCCH candidates with a smaller or larger CORESET SS set ID, (4-6) PDCCH candidates of a CORESET included in the same CORESET pool index as the CORESET pool index related to the PUCCH resource indicated by the above DCI (however, if an association between a PUCCH resource and a CORESET pool index is configured / specified).

[0148] When multiple of the above (4-0) to (4-6) are supported, which condition applies may be configured / activated / indicated to the UE using higher layer signaling (e.g., RRC signaling, MAC CE), physical layer signaling (e.g., DCI), or a combination thereof. Also, there may be one or more PDCCH candidates for each of the above (4-0) to (4-6).

[0149] It may be assumed that a repeated DCI can be the "last DCI format" only if the referenced PDCCH candidate falls under the same CORESET pool index. In other words, a repeated DCI may be taken into account (can be the "last DCI format") for determining a PUCCH resource with the same CORESET pool index as the reference PDCCH candidate. A repeated DCI may be ignored (does not become the "last DCI format") for determining a PUCCH resource with a different CORESET pool index than the reference PDCCH candidate.

[0150] Note that the determination of the PUCCH resource based on at least one of the above (4-0) to (4-6) may be applied when the two linked PDCCH candidates belong to the same PDCCH monitoring occasion, or when they belong to different PDCCH monitoring occasions. Also, the method of determining the PUCCH resource based on at least one of the above (4-0) to (4-6) may differ depending on whether the two linked PDCCH candidates belong to the same PDCCH monitoring occasion or different PDCCH monitoring occasions.

[0151] 9 and 10 are diagrams showing an example of determining the final DCI format in the fourth embodiment. Points that will not be described may be the same as those in FIG.

[0152] 9 corresponds to the case according to (4-1) above. In this case, the repeated DCI may be the last DCI format for the first CORESET. In this example, the last DCI is DCI#2-1.

[0153] Since the content of the repeated DCI is the same, the value of the PRI field indicated by DCI#2-1 and DCI#2-2 is the same. In the present disclosure, the PUCCH resource may be determined based on the PRI alone, or may be determined based on the PRI and other parameters (for example, at least one of the CCE index in which the last DCI was detected, the number of CCEs in the CORESET used to detect the last DCI, etc.).

[0154] 10 corresponds to the case according to (4-2) above. In this case, the repeated DCI may be the last DCI format for the second CORESET. In this example, the last DCI is DCI#2-2.

[0155] In addition, the determination of the type 1 HARQ-ACK codebook based on at least one of the above (2-0) to (2-6) and the determination of the PUCCH resource based on at least one of the above (4-0) to (4-6) may be used in any combination.

[0156] In addition, the determination of the type 2 HARQ-ACK codebook based on at least one of (3-1) to (3-6) above and the determination of the PUCCH resource based on at least one of (4-0) to (4-6) above may be used in any combination.

[0157] For example, the following combinations may be used to determine the HARQ-ACK codebook and the PUCCH resource: (2-0) and (4-0), (2-1) / (3-1) and (4-1), (2-2) / (3-2) and (4-2), (2-3) / (3-3) and (4-3), (2-4) / (3-4) and (4-4), (2-5) / (3-5) and (4-5), (2-6) / (3-6) and (4-6). These combinations correspond to cases where the reference PDCCH candidates for determining the HARQ-ACK codebook and the reference PDCCH candidates for determining the PUCCH resources are determined based on the same rule.

[0158] According to the fourth embodiment described above, when two linked CORESETs are used for PDCCH repetition, the UE can determine an appropriate PUCCH resource for HARQ-ACK transmission.

[0159] <Other> It should be noted that at least one of the above-described embodiments may be applied only to UEs that have reported or support a particular UE capability.

[0160] The specific UE capabilities may indicate at least one of the following: Whether to support multi-TRP PDCCH repetition scheme; Whether to support two (or more) PDCCH repetitions in two (or more) CORESETs with different CORESET pool indices; Whether to support two (or more) PDCCH repetitions in two (or more) CORESETs with different CORESET pool indices in the case of joint HARQ-ACK feedback; In the case of joint HARQ-ACK feedback for Type 1 (or Type 2) HARQ-ACK codebook, whether to support two (or more) PDCCH repetitions in two (or more) CORESETs with different CORESET pool indices.

[0161] Furthermore, at least one of the above-described embodiments may be applied when specific information related to the above-described embodiments is configured in the UE by higher layer signaling (if not configured, for example, the operation of Rel. 15 / 16 applies). For example, the specific information may be information indicating enabling a PDCCH repetition scheme for different CORESET pool indices, information indicating configuring two CORESETs related to two linked SS sets, any RRC parameter for a specific release (e.g., Rel. 17), etc.

[0162] (wireless communication system) The configuration of a wireless communication system according to an embodiment of the present disclosure will be described below. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above embodiments of the present disclosure or a combination thereof.

[0163] 11 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. The wireless communication system 1 may be a system that realizes communication using Long Term Evolution (LTE) or 5th generation mobile communication system New Radio (5G NR) specified by the Third Generation Partnership Project (3GPP).

[0164] The wireless communication system 1 may also support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

[0165] 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.

[0166] The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity in which both the MN and the SN are NR base stations (gNBs) (NR-NR Dual Connectivity (NN-DC))).

[0167] The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with a relatively wide coverage, and base stations 12 (12a-12c) that are located within the macrocell C1 and form small cells C2 that are smaller than the macrocell C1. A user terminal 20 may be located within at least one of the cells. The locations and numbers of the cells and user terminals 20 are not limited to the embodiment shown in the figure. Hereinafter, when there is no need to distinguish between the base stations 11 and 12, they will be collectively referred to as base station 10.

[0168] 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).

[0169] Each CC may be included in at least one of a first frequency band (Frequency Range 1 (FR1)) and a second frequency band (Frequency Range 2 (FR2)). The macro cell C1 may be included in FR1, and the small cell C2 may be included in FR2. For example, FR1 may be a frequency band of 6 GHz or less (sub-6 GHz), and FR2 may be a frequency band above 24 GHz (above-24 GHz). Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may be a frequency band higher than FR2.

[0170] Furthermore, the user terminal 20 may perform communication using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD) in each CC.

[0171] The multiple base stations 10 may be connected by wire (for example, optical fiber conforming to the Common Public Radio Interface (CPRI), an X2 interface, or the like) or wirelessly (for example, NR communication). For example, when NR communication is used as a backhaul between the base stations 11 and 12, the base station 11 corresponding to the upper station may be called an Integrated Access Backhaul (IAB) donor, and the base station 12 corresponding to the relay station (relay) may be called an IAB node.

[0172] The base station 10 may be connected to the core network 30 directly or via another base station 10. The core network 30 may include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), and the like.

[0173] The user terminal 20 may be a terminal compatible with at least one of communication methods such as LTE, LTE-A, and 5G.

[0174] An Orthogonal Frequency Division Multiplexing (OFDM)-based radio access scheme may be used in the radio communication system 1. For example, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), or the like may be used in at least one of the downlink (DL) and uplink (UL).

[0175] The radio access scheme may also be called a waveform. Note that in the wireless communication system 1, other radio access schemes (for example, other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the UL and DL radio access schemes.

[0176] In the wireless communication system 1, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20, a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc. may be used as the downlink channel.

[0177] Furthermore, in the wireless communication system 1, an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20, an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), etc. may be used as an uplink channel.

[0178] The PDSCH transmits user data, higher layer control information, System Information Block (SIB), etc. The PUSCH may transmit user data, higher layer control information, etc. Furthermore, the PBCH may transmit Master Information Block (MIB).

[0179] Lower layer control information may be transmitted by the PDCCH. The lower layer control information may include, for example, Downlink Control Information (DCI) including scheduling information for at least one of the PDSCH and the PUSCH.

[0180] Note that the DCI for scheduling the PDSCH may be referred to as a DL assignment, a DL DCI, etc., and the DCI for scheduling the PUSCH may be referred to as an UL grant, a UL DCI, etc. Note that the PDSCH may be interpreted as DL data, and the PUSCH may be interpreted as UL data.

[0181] A control resource set (CORESET) and a search space may be used to detect the PDCCH. The CORESET corresponds to resources to search for DCI. The search space corresponds to a search region and a search method for PDCCH candidates. One CORESET may be associated with one or more search spaces. The UE may monitor a CORESET associated with a certain search space based on the search space configuration.

[0182] One search space may correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may be called a search space set. Note that the terms "search space," "search space set," "search space setting," "search space set setting," "CORESET," "CORESET setting," etc. in the present disclosure may be read interchangeably.

[0183] The PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), acknowledgement information (which may be called, for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR). The PRACH may transmit a random access preamble for establishing a connection with a cell.

[0184] In the present disclosure, downlink, uplink, etc. may be expressed without adding "link." Also, various channels may be expressed without adding "Physical" to the beginning.

[0185] 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, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), a phase tracking reference signal (PTRS), etc. may be transmitted as DL-RS.

[0186] 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 the SS (PSS, SSS) and the PBCH (and DMRS for the PBCH) may be referred to as an SS / PBCH block, an SS Block (SSB), or the like. Note that the SS, SSB, and the like may also be referred to as reference signals.

[0187] Furthermore, in the wireless communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), etc. may be transmitted as an uplink reference signal (UL-RS). Note that the DMRS may also be called a user equipment-specific reference signal (UE-specific reference signal).

[0188] (base station) 12 is a diagram showing an example of the configuration of a base station according to an embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission line interface 140. Note that the base station may include one or more of each of the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission line interface 140.

[0189] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the base station 10 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0190] The control unit 110 performs overall control of the base station 10. The control unit 110 can be configured from a controller, a control circuit, and the like that are explained based on common understanding in the technical field to which the present disclosure relates.

[0191] The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may control transmission and reception using the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140, measurement, etc. The control unit 110 may generate data to be transmitted as signals, control information, sequences, etc., and transfer them to the transceiver unit 120. The control unit 110 may perform call processing (setting up, releasing, etc.) of communication channels, status management of the base station 10, management of radio resources, etc.

[0192] The transceiver unit 120 may include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0193] The transmitting / receiving unit 120 may be configured as an integrated transmitting / receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 1211 and an RF unit 122. The receiving unit may be composed of a reception processing unit 1212, an RF unit 122, and a measurement unit 123.

[0194] The transmitting and receiving antenna 130 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure pertains, such as an array antenna.

[0195] The transceiver 120 may transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 120 may receive the above-mentioned uplink channel, uplink reference signal, etc.

[0196] The transceiver 120 may form at least one of a transmission beam and a reception beam using digital beamforming (for example, precoding), analog beamforming (for example, phase rotation), or the like.

[0197] The transceiver 120 (transmission processing unit 1211) may perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

[0198] The transceiver 120 (transmission processor 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0199] The transmitting / receiving unit 120 (RF unit 122) may perform modulation to a radio frequency band, filtering, amplification, etc. on the baseband signal, and transmit the radio frequency band signal via the transmitting / receiving antenna .

[0200] 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 .

[0201] The transceiver 120 (reception processing unit 1212) may apply reception processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, thereby acquiring user data, etc.

[0202] The transceiver 120 (measurement unit 123) may perform measurements on the received signal. For example, the measurement unit 123 may perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 110.

[0203] The transmission path interface 140 may transmit and receive signals (backhaul signaling) between devices included in the core network 30, other base stations 10, etc., and may acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

[0204] The transmitting section and receiving section of the base station 10 in the present disclosure may be configured by at least one of the transmitting / receiving section 120, the transmitting / receiving antenna 130, and the transmission path interface 140.

[0205] The transceiver 120 may transmit a configuration for two Physical Downlink Control Channel (PDCCH) candidates that are linked to each other to the user terminal 20. The configuration may be at least one of information on the linking (association) of the two SS sets, information on the two linked CORESETs, information on the two linked PDCCH candidates in the two SS sets, and the like.

[0206] When joint Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback is configured, the transceiver 120 may receive HARQ-ACK information included in a HARQ-ACK codebook determined by the terminal, with the HARQ-ACK corresponding to a reference PDCCH candidate among the two PDCCH candidates as valid HARQ-ACK information.

[0207] The control unit 110 may generate information on a Downlink Assignment Index (DAI) included in the downlink control information transmitted using the two PDCCH candidates so as to indicate a DAI corresponding to a reference PDCCH candidate among the two PDCCH candidates.

[0208] When the downlink control information transmitted using the two PDCCH candidates corresponds to a reference PDCCH candidate among the two PDCCH candidates, the transceiver 120 may receive uplink control information (UCI, for example, HARQ-ACK) transmitted using an uplink control channel resource (PUCCH resource) determined based on the downlink control information.

[0209] (user terminal) 13 is a diagram showing an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transceiver unit 220, and a transmitting / receiving antenna 230. Note that the user terminal 20 may include one or more of each of the control unit 210, the transceiver unit 220, and the transmitting / receiving antenna 230.

[0210] Note that this example mainly shows functional blocks of the characteristic parts of the present embodiment, and it may be assumed that the user terminal 20 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0211] The control unit 210 performs overall control of the user terminal 20. The control unit 210 can be configured from a controller, a control circuit, and the like that are explained based on common understanding in the technical field to which the present disclosure relates.

[0212] The control unit 210 may control signal generation, mapping, etc. The control unit 210 may also control transmission and reception, measurement, etc. using the transceiver unit 220 and the transceiver antenna 230. The control unit 210 may generate data, control information, sequences, etc. to be transmitted as signals, and transfer them to the transceiver unit 220.

[0213] The transceiver unit 220 may include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may be configured from a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0214] The transmitting / receiving unit 220 may be configured as an integrated transmitting / receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 2211 and an RF unit 222. The receiving unit may be composed of a reception processing unit 2212, an RF unit 222, and a measurement unit 223.

[0215] The transmitting / receiving antenna 230 can be configured as an antenna described based on common understanding in the technical field to which the present disclosure pertains, such as an array antenna.

[0216] The transceiver 220 may receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 220 may transmit the above-mentioned uplink channel, uplink reference signal, etc.

[0217] The transceiver 220 may form at least one of a transmission beam and a reception beam using digital beamforming (for example, precoding), analog beamforming (for example, phase rotation), or the like.

[0218] The transceiver 220 (transmission processing unit 2211) may perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

[0219] The transceiver 220 (transmission processor 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0220] Whether or not to apply DFT processing may be based on the setting of transform precoding. When transform precoding is enabled for a certain channel (e.g., PUSCH), the transceiver unit 220 (transmission processing unit 2211) may perform DFT processing as the transmission processing to transmit the channel using a DFT-s-OFDM waveform, and when transform precoding is not enabled, the transceiver unit 220 may not perform DFT processing as the transmission processing.

[0221] The transmitting / receiving unit 220 (RF unit 222) may perform modulation to a radio frequency band, filtering, amplification, etc. on the baseband signal, and transmit the radio frequency band signal via the transmitting / receiving antenna 230.

[0222] 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.

[0223] The transceiver 220 (reception processing unit 2212) may apply reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal to acquire user data, etc.

[0224] The transceiver 220 (measurement unit 223) may perform measurements on the received signal. For example, the measurement unit 223 may perform RRM measurement, CSI measurement, etc. based on the received signal. The measurement unit 223 may measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 210.

[0225] The transmitting section and receiving section of the user terminal 20 in the present disclosure may be configured by at least one of the transmitting / receiving section 220 and the transmitting / receiving antenna 230.

[0226] The transceiver 220 may receive configuration for two Physical Downlink Control Channel (PDCCH) candidates that are linked to each other. The configuration may be at least one of information on the linking (association) of the two SS sets, information on the two linked CORESETs, information on the two linked PDCCH candidates in the two SS sets, etc.

[0227] When joint Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback is configured, the control unit 210 may determine a HARQ-ACK codebook by using the HARQ-ACK corresponding to the reference PDCCH candidate among the two PDCCH candidates as valid HARQ-ACK information.

[0228] The control unit 210 may assume that information of the Downlink Assignment Index (DAI) (DAI field, C-DAI, T-DAI, etc.) included in the Downlink Control Information (DCI) transmitted using the two PDCCH candidates indicates the DAI corresponding to the reference PDCCH candidate among the two PDCCH candidates.

[0229] When the downlink control information transmitted using the two PDCCH candidates corresponds to a reference PDCCH candidate among the two PDCCH candidates, the control unit 210 may use the downlink control information to determine an uplink control channel resource.

[0230] The reference PDCCH candidate may be a PDCCH candidate of a Control Resource Set (CORESET) for which no CORESET pool index is provided or for which a CORESET pool index value=0 is provided.

[0231] The reference PDCCH candidate may be a PDCCH candidate of a Control Resource Set (CORESET) to which a CORESET pool index value=1 is provided.

[0232] The reference PDCCH candidate may be the PDCCH candidate with an earlier PDCCH monitoring opportunity of the two PDCCH candidates.

[0233] (Hardware configuration) The block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining the single device or multiple devices with software.

[0234] Here, the functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, deeming, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission may be called a transmitting unit, transmitter, etc. As mentioned above, the implementation method of each is not particularly limited.

[0235] For example, a base station, a user terminal, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 14 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. The above-described base station 10 and user terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0236] In this disclosure, terms such as apparatus, circuit, device, section, unit, etc. may be read interchangeably. The hardware configurations of the base station 10 and the user terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0237] For example, although only one processor 1001 is shown, there may be multiple processors. Furthermore, processing may be performed by one processor, or processing may be performed by two or more processors simultaneously, serially, or in other ways. Furthermore, processor 1001 may be implemented by one or more chips.

[0238] 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 a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication via the communication device 1004, and control at least one of reading and writing data in the memory 1002 and the storage 1003.

[0239] The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, at least a part of the above-mentioned control unit 110 (210), transmission / reception unit 120 (220), etc. may be realized by the processor 1001.

[0240] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 110 (210) may be realized by a control program stored in the memory 1002 and running on the processor 1001, and the other functional blocks may be realized in a similar manner.

[0241] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), or other suitable storage medium. The memory 1002 may also be referred to as a register, a cache, a main memory, or the like. The memory 1002 may store executable programs (program codes), software modules, and the like for implementing a wireless communication method according to an embodiment of the present disclosure.

[0242] Storage 1003 is a computer-readable recording medium and may be constituted by at least one of, for example, a flexible disk, a floppy disk, a magneto-optical disk (e.g., a compact disc (e.g., a Compact Disc ROM (CD-ROM)), a digital versatile disc, a Blu-ray disc), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, stick, key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as a secondary storage device.

[0243] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the above-mentioned transmission / reception unit 120 (220), transmission / reception antenna 130 (230), etc. may be realized by the communication device 1004. The transmission / reception unit 120 (220) may be implemented as a transmission unit 120a (220a) and a reception unit 120b (220b) that are physically or logically separated.

[0244] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (for example, a display, a speaker, a light emitting diode (LED) lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0245] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0246] Furthermore, the base station 10 and the user terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized using such hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0247] (Variation) Note that terms explained in the present disclosure and terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may be interchangeable. A signal may also be a message. A reference signal may be abbreviated as RS, and may also be called a pilot, pilot signal, etc. depending on the applicable standard. A component carrier (CC) may also be called a cell, frequency carrier, carrier frequency, etc.

[0248] A radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting a radio frame may be called a subframe. Furthermore, a subframe may be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0249] Here, the numerology may be a communication parameter applied to at least one of transmission and reception of a signal or channel, and may indicate at least one of, for example, a subcarrier spacing (SCS), a bandwidth, a symbol length, a cyclic prefix length, a transmission time interval (TTI), the number of symbols per TTI, a radio frame structure, a specific filtering process performed by a transceiver in the frequency domain, and a specific windowing process performed by a transceiver in the time domain.

[0250] A slot may be composed of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol), and may be a time unit based on numerology.

[0251] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (PUSCH) mapping type B.

[0252] A radio frame, a subframe, a slot, a minislot, and a symbol all represent time units for transmitting signals. The radio frame, the subframe, the slot, the minislot, and the symbol may be referred to by other names corresponding to the radio frame, the subframe, the slot, the minislot, and the symbol. Note that the time units such as a frame, a subframe, a slot, a minislot, and a symbol in the present disclosure may be interchangeable.

[0253] For example, one subframe may be referred to as a TTI, or multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0254] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. However, the definition of TTI is not limited to this.

[0255] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0256] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0257] A TTI having a time length of 1 ms may be called a regular TTI (TTI in 3GPP Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0258] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0259] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may also be determined based on numerology.

[0260] In addition, an RB may include one or more symbols in the time domain and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0261] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0262] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0263] A Bandwidth Part (BWP), which may also be referred to as a fractional bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0264] The BWP may include an UL BWP (a BWP for UL) and a DL BWP (a BWP for DL). One or more BWPs may be configured for a UE within one carrier.

[0265] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given channel / signal outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0266] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0267] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by a predetermined index.

[0268] The names used for parameters and the like in this disclosure are not intended to be limiting in any way. Furthermore, the mathematical expressions and the like using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0269] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0270] Furthermore, information, signals, etc. may be output from a higher layer to a lower layer and / or from a lower layer to a higher layer. Information, signals, etc. may be input / output via multiple network nodes.

[0271] Input and output information, signals, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information, signals, etc. may be overwritten, updated, or added. Output information, signals, etc. may be deleted. Input information, signals, etc. may be transmitted to another device.

[0272] Notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, notification of information in the present disclosure may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB)), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0273] Note that the physical layer signaling may be called Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), L1 control information (L1 control signal), etc. Furthermore, the RRC signaling may be called an RRC message, such as an RRC connection setup message or an RRC connection reconfiguration message. Furthermore, the MAC signaling may be notified using, for example, a MAC Control Element (CE).

[0274] Furthermore, notification of specified information (e.g., notification that "it is X") is not limited to explicit notification, but may be made implicitly (e.g., by not notifying the specified information or by notifying other information).

[0275] The determination may be made by a value represented by one bit (0 or 1), by a Boolean value represented by true or false, or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0276] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0277] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0278] As used in this disclosure, the terms "system" and "network" may be used interchangeably. A "network" may refer to devices included in the network (e.g., base stations).

[0279] In the present 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," "antenna port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," etc. may be used interchangeably.

[0280] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNB (eNodeB)," "gNB (gNodeB)," "access point," "transmission point (TP)," "reception point (RP)," "transmission / reception point (TRP)," "panel," "cell," "sector," "cell group," "carrier," "component carrier," etc. may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, picocell, etc.

[0281] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication service within this coverage.

[0282] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0283] A mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0284] 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 be a device mounted on a mobile object, or the mobile object itself. The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0285] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the user terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0286] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station 10 may be configured to have the functions of the user terminal 20 described above.

[0287] In the present disclosure, an operation described as being performed by a base station may be performed by its upper node in some cases. It is apparent that in a network including one or more network nodes having a base station, various operations performed for communication with a terminal may be performed by the base station, one or more network nodes other than the base station (such as, but not limited to, a Mobility Management Entity (MME) and a Serving-Gateway (S-GW)), or a combination thereof.

[0288] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, the order of the processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the specific order presented.

[0289] Each aspect / embodiment described in the present disclosure may be related to 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) (xG (x is, for example, an integer or a 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 (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE The present invention may be applied to systems that use 802.20, Ultra-Wide Band (UWB), Bluetooth (registered trademark), or other appropriate wireless communication methods, or to next-generation systems that are based on and extend these systems. Furthermore, the present invention may be applied to a combination of multiple systems (for example, a combination of LTE or LTE-A and 5G).

[0290] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0291] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0292] The term "determining," as used in this disclosure, may encompass a wide variety of actions. For example, "determining" may be considered to be judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., looking up in a table, database, or another data structure), ascertaining, etc.

[0293] Additionally, "determining" may be considered to be "determining" receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), etc.

[0294] Also, "decision" may be considered to be "deciding" resolving, selecting, choosing, establishing, comparing, etc. In other words, "decision" may be considered to be "deciding" on some action.

[0295] Furthermore, "judgment (decision)" may be interpreted as "assuming," "expecting," "considering," or the like.

[0296] As used in this disclosure, the terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access."

[0297] In this disclosure, when two elements are connected, they may be considered to be "connected" or "coupled" to one another using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy having wavelengths in the radio frequency range, microwave range, light (both visible and invisible) range, etc., as some non-limiting and non-exhaustive examples.

[0298] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0299] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0300] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0301] Although the invention according to the present disclosure has been described in detail above, it is clear to those skilled in the art that the invention according to the present disclosure is not limited to the embodiments described in the present disclosure. The invention according to the present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the description of the claims. Therefore, the description of the present disclosure is intended to be illustrative and explanatory and does not impose any limiting meaning on the invention according to the present disclosure.

Claims

1. a receiver for receiving configurations for two Physical Downlink Control Channel (PDCCH) candidates linked together; and a control unit that, when joint HARQ-ACK feedback is configured in which Hybrid Automatic Repeat reQuest ACKnowledgements (HARQ-ACKs) of a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) received from multiple transmission / reception points (Transmission / Reception Points (TRPs)) are collectively transmitted using resources of the same uplink channel, determines a HARQ-ACK codebook using a HARQ-ACK corresponding to a reference PDCCH candidate from the two PDCCH candidates as valid HARQ-ACK information.

2. 2. The terminal according to claim 1, wherein the control unit assumes that information of a Downlink Assignment Index (DAI) included in downlink control information transmitted using the two PDCCH candidates indicates a DAI corresponding to a reference PDCCH candidate among the two PDCCH candidates.

3. 3. The terminal according to claim 1, wherein, when downlink control information transmitted using the two PDCCH candidates corresponds to a reference PDCCH candidate among the two PDCCH candidates, the control unit uses the downlink control information to determine an uplink control channel resource.

4. The terminal according to any one of claims 1 to 3, wherein the reference PDCCH candidate is a PDCCH candidate of a control resource set (CORESET) for which no control resource set (CORESET) pool index is provided or for which a CORESET pool index value = 0 is provided.

5. receiving configurations for two interlinked Physical Downlink Control Channel (PDCCH) candidates; and determining a HARQ-ACK codebook using a HARQ-ACK corresponding to a reference PDCCH candidate of the two PDCCH candidates as valid HARQ-ACK information when joint HARQ-ACK feedback is configured, in which Hybrid Automatic Repeat reQuest ACKnowledgements (HARQ-ACKs) of a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) received from a plurality of transmission / reception points (Transmission / Reception Points (TRPs)) are collectively transmitted using resources of the same uplink channel.

6. a transmitter that transmits configurations for two Physical Downlink Control Channel (PDCCH) candidates linked to each other to a terminal; a receiving unit that receives, when joint HARQ-ACK feedback is configured in which Hybrid Automatic Repeat reQuest ACKnowledgements (HARQ-ACKs) of a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) received from a plurality of transmission / reception points (Transmission / Reception Points (TRPs)) are collectively transmitted using resources of the same uplink channel, a HARQ-ACK corresponding to a reference PDCCH candidate of the two PDCCH candidates as valid HARQ-ACK information included in a HARQ-ACK codebook determined by the terminal.

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