Terminal, wireless communication method, and base station

Abstract

A terminal according to one aspect of the present disclosure includes: a receiving unit that receives an initial transmission of downlink (DL) data that is multicast; and a control unit that controls reception of a retransmission of the DL data that is multicast based on a decoding result of the DL data. According to one aspect of the present disclosure, it is possible to appropriately transmit a HARQ-ACK corresponding to a multicast PDSCH.

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 Art

[0002] In a Universal Mobile Telecommunications System (UMTS) network, Long Term Evolution (LTE) has been standardized for the purpose of further high-speed data rates, low latency, etc. (Non-Patent Document 1). In addition, for the purpose of further large capacity and high performance of LTE (3rd Generation Partnership Project (3GPP) Release (Rel.) 8, 9), LTE-Advanced (3GPP Rel. 10-14) has been standardized.

[0003] Research is also being conducted on a successor system to LTE (for example, also referred to as the 5th generation mobile communication system (5G), 5G+ (plus), 6th generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 and later, etc.).

[0004] Prior Art Documents

[0005] Non-Patent Documents

[0006] 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

[0007] Problems to be Solved by the Invention

[0008] In a future wireless communication system (e.g., NR), it is envisioned that multiple user terminals (user terminal, User Equipment (UE)) communicate in an ultra-high density and high traffic environment.

[0009] In NR, it is envisioned that in such an environment, multiple UEs receive the same PDSCH while utilizing multicast.

[0010] However, in the NR specifications to date, there has been insufficient research on the retransmission method of HARQ-ACK corresponding to the PDSCH that utilizes multicast of UEs. If this method cannot be appropriately controlled, there is a concern about a degradation in system performance such as a reduction in throughput.

[0011] Therefore, one of the objectives of the present disclosure is to provide a terminal, a wireless communication method, and a base station that appropriately transmit HARQ-ACK corresponding to the multicast PDSCH.

[0012] Means for Solving the Problem

[0013] A terminal according to one aspect of the present disclosure includes: a receiving unit that receives an initial transmission of downlink (DL) data that is multicast; and a control unit that controls the reception of a retransmission of the DL data that is multicast based on a decoding result of the DL data.

[0014] Effects of the Invention

[0015] According to one aspect of the present disclosure, it is possible to appropriately transmit HARQ-ACK corresponding to the multicast PDSCH. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. is a diagram showing an example of a retransmission process of a multicast PDSCH.

[0017] Figure 2 FIG. is a diagram showing another example of a retransmission process of a multicast PDSCH.

[0018] Figures 3A - 3C FIG. is a diagram showing an example of DCI-based resource indication for an initial transmission of a multicast PDSCH and a retransmission of a multicast PDSCH.

[0019] Figures 4A - 4C FIG. is a diagram showing an example of a method for determining HARQ feedback timing / HARQ-ACK transmission resources for an initial transmission of a multicast PDSCH and a retransmission of a multicast PDSCH.

[0020] Figure 5 FIG. is a diagram showing an example of a retransmission process of a multicast PDSCH.

[0021] Figure 6 This is a diagram showing an example of the retransmission process of the multicast PDSCH.

[0022] Figure 7 This is a diagram showing an example of the reception timing of DCI for scheduling the retransmission of the multicast PDSCH.

[0023] Figure 8 This is a diagram showing an example of the reception timing of DCI for scheduling the retransmission of the multicast PDSCH.

[0024] Figure 9 This is a diagram showing an example of the repeated transmission of the multicast PDSCH.

[0025] Figure 10 This is a diagram showing an example of the repeated transmission of the multicast PDSCH.

[0026] Figure 11 This is a diagram showing an example of the repeated transmission of the multicast PDSCH.

[0027] Figure 12 This is a diagram showing an example of HARQ-ACK transmission for the repeated transmission of the multicast PDSCH.

[0028] Figure 13 This is a diagram showing an example of HARQ-ACK transmission for the repeated transmission of the multicast PDSCH.

[0029] Figure 14 This is a diagram showing an example of the reference of high-layer parameters for unicast DCI and multicast DCI.

[0030] Figure 15 This is a diagram showing an example of the schematic structure of a wireless communication system according to an embodiment.

[0031] Figure 16 This is a diagram showing an example of the structure of a base station according to an embodiment.

[0032] Figure 17 This is a diagram showing an example of the structure of a user terminal according to an embodiment.

[0033] Figure 18 This is a diagram showing an example of the hardware structure of a base station and a user terminal according to an embodiment. Detailed Embodiments

[0034] (TCI, Spatial Relationship, QCL)

[0035] In NR, the following is being studied: based on the Transmission Configuration Indication state (TCI state), the receiving process (e.g., at least one of receiving, demapping, demodulating, decoding) and the transmitting process (e.g., at least one of transmitting, mapping, precoding, modulating, encoding) in a UE for at least one of a control signal and a channel (hereinafter referred to as a signal / channel).

[0036] The TCI state can also represent the state of a signal / channel applied to the downlink. A state corresponding to the TCI state of a signal / channel applied to the uplink can also be expressed as a spatial relation.

[0037] The TCI state refers to information related to the Quasi-Co-Location (QCL) of a signal / channel, and can also be referred to as a spatial reception parameter, Spatial Relation Information, etc. The TCI state can also be set for a UE on a per-channel or per-signal basis.

[0038] In addition, in the present disclosure, the TCI state can also be interchanged with at least one of a DL TCI state, a UL TCI state, a unified TCI state, a default TCI state, a spatial relation, a default spatial relation, QCL, a QCL relation, a QCL assumption, and a QCL type.

[0039] QCL is an index representing the statistical properties of a signal / channel. For example, when a certain signal / channel and other signal / channels are in a QCL relationship, it can also mean that among these different multiple signal / channels, it is possible to assume that at least one of a Doppler shift, a Doppler spread, an average delay, a delay spread, and a spatial parameter (e.g., a spatial Rx parameter) is the same (QCL for at least one of these).

[0040] In addition, the spatial reception parameter can also correspond to a receiving beam of a UE (e.g., a receiving analog beam), and the beam can also be determined based on spatial QCL. The QCL (or an element of at least one of QCLs) in the present disclosure can also be replaced by sQCL (spatial QCL).

[0041] The QCL can also be specified in multiple types (QCL types). For example, four different QCL types A - D can be set with parameters (or parameter sets) that can be assumed to be the same. Hereinafter, these parameters (which can also be referred to as QCL parameters) are presented:

[0042] · QCL type A (QCL - A): Doppler shift, Doppler spread, mean delay, and delay spread,

[0043] · QCL type B (QCL - B): Doppler shift and Doppler spread,

[0044] · QCL type C (QCL - C): Doppler shift and mean delay,

[0045] · QCL type D (QCL - D): Spatial reception parameter.

[0046] The situation where the UE assumes that a specific control resource set (Control Resource Set (CORESET)), channel, or reference signal has a specific QCL (e.g., QCL type D) relationship with other CORESETs, channels, or reference signals can also be referred to as a QCL assumption.

[0047] The UE can also determine at least one of the transmission beam (Tx beam) and reception beam (Rx beam) of the signal / channel based on the TCI state of the signal / channel or the QCL assumption.

[0048] The TCI state can also be, for example, information related to the QCL between the target channel (in other words, the reference signal (Reference Signal (RS)) used for this channel) and other signals (e.g., other RS). The TCI state can also be set (indicated) through higher - layer signaling, physical - layer signaling, or a combination of them.

[0049] In this disclosure, the higher - layer signaling can be, for example, any one of or a combination of radio resource control (Radio Resource Control (RRC)) signaling, medium access control (Medium Access Control (MAC)) signaling, broadcast information, etc.

[0050] MAC signaling can also use, for example, MAC control elements (MAC CE), MAC protocol data units (PDU), etc. Broadcast information can also be, for example, the Master Information Block (MIB), System Information Block (SIB), minimum system information (Remaining Minimum System Information (RMSI)), other system information (Other System Information (OSI)), etc.

[0051] Physical layer signaling can also be, for example, Downlink Control Information (DCI).

[0052] Channels configured (designated) with TCI states or spatial relationships can also be, for example, at least one of the Downlink Shared Channel (Physical Downlink Shared Channel (PDSCH)), Downlink Control Channel (Physical Downlink Control Channel (PDCCH)), Uplink Shared Channel (Physical Uplink Shared Channel (PUSCH)), and Uplink Control Channel (Physical Uplink Control Channel (PUCCH)).

[0053] In addition, the RS that has a QCL relationship with this channel can also be, for example, at least one of the Synchronization Signal Block (SSB), Channel State Information Reference Signal (CSI-RS), Measurement Reference Signal (Sounding Reference Signal (SRS)), Tracking CSI-RS (also known as Tracking Reference Signal (TRS)), and QCL Detection Reference Signal (also known as QRS).

[0054] An SSB is a signal block that includes at least one of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a broadcast channel (Physical Broadcast Channel (PBCH)). An SSB may also be referred to as an SS / PBCH block.

[0055] The information element of the TCI state (the "TCI-state IE" of RRC) set by higher layer signaling may also include one or more QCL information ("QCL-Info"). The QCL information may also include at least one of information related to the RS that is in a QCL relationship (RS relationship information) and QCL type information (QCL type information). The RS relationship information may also include information such as the index of the RS (e.g., SSB index, Non-Zero-Power (NZP) CSI-RS resource ID (identifier)), the index of the cell where the RS is located, the index of the Bandwidth Part (BWP) where the RS is located, etc.

[0056] In Rel.15 NR, as the TCI state of at least one of PDCCH and PDSCH, both the RS of QCL type A and the RS of QCL type D, or only the RS of QCL type A can be set for the UE.

[0057] In the case where the TRS is set as the RS of QCL type A, it is assumed that the TRS is different from the DeModulation Reference Signal (DMRS) of PDCCH or PDSCH, and the same TRS is transmitted periodically for a long time. The UE can measure the TRS and calculate the average delay, delay spread, etc.

[0058] The UE in which the TRS is set as the RS of QCL type A in the TCI state of the DMRS of PDCCH or PDSCH can assume that the DMRS of PDCCH or PDSCH and the QCL type A parameters (average delay, delay spread, etc.) of the TRS are the same, and thus can obtain the type A parameters (average delay, delay spread, etc.) of the DMRS of PDCCH or PDSCH based on the measurement results of the TRS. When the UE performs channel estimation of at least one of PDCCH and PDSCH, it can use the measurement results of the TRS to perform more accurate channel estimation.

[0059] A UE with an RS configured with QCL type D can use the RS of QCL type D to determine the UE receive beam (spatial domain receive filter, UE spatial domain receive filter).

[0060] The RS of QCL type X in a TCI state may also refer to an RS that has a QCL type X relationship with a certain channel / signal (DMRS thereof), and this RS may also be referred to as the QCL source of QCL type X in this TCI state.

[0061] (Default TCI state / default spatial relationship / default PL-RS)

[0062] In RRC connected mode, in both the case where the TCI information (higher layer parameter TCI-PresentInDCI) in DCI is set to "valid (enabled)" and the case where the TCI information in DCI is not configured, when the time offset between the reception of a DL DCI (DCI scheduling PDSCH) and the corresponding PDSCH (PDSCH scheduled by this DCI) is less than a threshold (timeDurationForQCL) (application condition, first condition), in the case of non-cross-carrier scheduling, the TCI state of the PDSCH (default TCI state) may also be the TCI state of the lowest CORESET ID in the latest time slot within the active DL BWP of this (specific UL signal) CC. If this is not the case, the TCI state of the DSCH (default TCI state) may also be the TCI state of the lowest TCI state ID of the PDSCH within the active DL BWP of the scheduled CC.

[0063] In Rel.15, each MAC CE for activation / deactivation of PUCCH spatial relationship and each MAC CE for activation / deactivation of SRS spatial relationship are required. The PUSCH spatial relationship follows the SRS spatial relationship.

[0064] In Rel.16, at least one of the MAC CE for activation / deactivation of PUCCH spatial relationship and the MAC CE for activation / deactivation of SRS spatial relationship may not be used.

[0065] In FR2, when neither the spatial relation for PUCCH nor PL-RS is configured (application condition, second condition), the default assumptions for the spatial relation and PL-RS (default spatial relation and default PL-RS) are applied to PUCCH. In FR2, when neither the spatial relation for SRS (SRS resource for SRS, or SRS resource corresponding to the SRI in DCI format 0_1 for scheduling PUSCH) nor PL-RS is configured (application condition, second condition), the default assumptions for the spatial relation and PL-RS (default spatial relation and default PL-RS) are applied to the PUSCH and SRS scheduled by DCI format 0_1.

[0066] When a CORESET is configured within the activated DL BWP on this CC, the default spatial relation and default PL-RS can also be the TCI state or QCL assumption of the CORESET with the lowest CORESET ID within this activated DL BWP. When no CORESET is configured within the activated DL BWP on this CC, the default spatial relation and default PL-RS can also be the activated TCI state with the lowest ID of the PDSCH within this activated DL BWP.

[0067] In Rel.15, the spatial relation of the PUSCH scheduled by DCI format 0_0 follows the spatial relation of the PUCCH resource with the lowest PUCCH resource ID among the activated spatial relations of the PUCCH on the same CC. Even when PUCCH is not transmitted on the SCell, the network needs to update the PUCCH spatial relations on all SCell.

[0068] In Rel.16, no PUCCH configuration is required for the PUSCH scheduled by DCI format 0_0. For the PUSCH scheduled by DCI format 0_0, when there is no activated PUCCH spatial relation or no PUCCH resource on the activated UL BWP within this CC (application condition, second condition), the default spatial relation and default PL-RS are applied to this PUSCH.

[0069] (NR multicast / broadcast)

[0070] In NR up to Rel.16, the transmission of at least one of the signals and channels from the NW to the UE (hereinafter referred to as signal / channel) is basically unicast transmission. In this case, it is assumed that each UE uses multiple reception opportunities (reception timing) corresponding to multiple beams (or panels) of the NW to receive the same downlink (DL) data signal / channel (e.g., downlink shared channel (PDSCH)) transmitted from the NW to multiple UEs.

[0071] In addition, in a situation of extremely high density and high traffic volume such as an environment where multiple UEs are geographically dense (e.g., a stadium, etc.), it is envisaged that multiple UEs receive the same signal / channel simultaneously. In this case, since multiple UEs are in the same area and each UE receives the same signal / channel, although it is possible to ensure the reliability of communication by each UE receiving the signal / channel through unicast, the resource utilization efficiency is reduced.

[0072] On the other hand, there are also use cases (e.g., televisions, radios, etc.) for multicasting (broadcasting) the same DL data signal / channel to multiple UEs. However, in this use case, the NW does not perform the reception confirmation of the DL data signal / channel of each UE, so it is difficult to ensure reliability.

[0073] Therefore, the inventors of the present invention have come up with a method for a UE to receive downlink control information (DCI) for scheduling a PDSCH that utilizes multicast, and a method for sending delivery confirmation information (e.g., which may also be referred to as Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) information, HARQ-ACK, ACK / NACK, etc.) corresponding to the PDSCH that utilizes multicast.

[0074] Hereinafter, with reference to the accompanying drawings, the embodiments related to the present disclosure will be described in detail. The wireless communication methods related to each embodiment can be applied separately or in combination.

[0075] (Wireless communication method)

[0076] Multicasting / broadcasting can also be set from the NW to multiple UEs. This setting of multicasting / broadcasting can also be performed using high-layer signaling.

[0077] The UE to which multicasting / broadcasting is set can also receive a PDSCH scheduled by DCI (PDCCH), and this DCI (PDCCH) is a DCI (PDCCH) blindly detected (received) in at least one of a downlink control channel (PDCCH) monitoring opportunity, search space, and Control Resource Set (CORESET) corresponding to the multicasting / broadcasting. This PDSCH can also be referred to as a PDSCH that utilizes multicast.

[0078] Furthermore, the UE to which multicasting / broadcasting is set can also use PUCCH or PUSCH to send HARQ-ACK / NACK for the PDSCH that utilizes multicast.

[0079] The HARQ-ACK / NACK can be sent as 1-bit HARQ-ACK / NACK for each transport block (TB) / codeword (CW) of the PDSCH that utilizes multicast, or can be sent as 1-bit HARQ-ACK / NACK for each of multiple TB / CWs.

[0080] In the present disclosure, multicast can also be interchanged with broadcast (announcing information). In addition, the PDSCH that utilizes multicast can also be interchanged with a PDSCH common to multiple UEs, a common PDSCH, a shared PDSCH, a multicast PDSCH, a broadcast (announcing) PDSCH, etc.

[0081] In the present disclosure, A / B can also mean at least one of A and B.

[0082] In the present disclosure, the PUCCH / PUSCH resource for HARQ-ACK transmission corresponding to the multicast PDSCH can also be simply referred to as the resource for HARQ-ACK transmission.

[0083] In the present disclosure, each of multiple UEs can also be referred to as each UE, and can be simply referred to as UE.

[0084] In the present disclosure, a DCI format dedicated to the multicast PDSCH can also be newly defined. When the multicast PDSCH is scheduled by the DCI format dedicated to the multicast PDSCH, the UE can also report UE capability information (UE Capability) related to whether or not the DCI format dedicated to the multicast PDSCH is supported to the network (NW, for example, gNB). In this case, the combination of DCI sizes (payload sizes, number of bits) increases, the number of blind detections of the DCI performed by the UE increases, and the complexity of UE operation increases. Therefore, only the UE that supports the DCI format can monitor the DCI format.

[0085] In the present disclosure, the multicast PDSCH can also be replaced with a reception timing, a timing, downlink (DL) data, data, a transport block (TB), a codeword (CW), a PDSCH, a multicast PUSCH, a PUSCH, etc.

[0086] Multiple DCIs can also respectively schedule more than one multicast PDSCH (reception timing). The same DL data can also be sent to multiple UEs in each of more than one multicast PDSCH. In the present disclosure, each of the multiple DCIs can also be referred to as a UE-dedicated DCI.

[0087] One DCI using QCL#x can also schedule DL data with QCL#x' for multiple UEs.

[0088] DCI detected in a PDCCH monitoring occasion associated with (corresponding to) a certain QCL may also schedule DL data in a reception occasion associated with the QCL.

[0089] PDCCH monitoring for multiple DCIs may also follow at least one of the following PDCCH monitoring methods 1 to 3.

[0090] [PDCCH Monitoring Method 1]

[0091] In a common search space or a group common search space, multiple DCIs may also be sent (received). The UE may also select a PDCCH monitoring occasion corresponding to the QCL set / indicated for PDCCH as the reception for DCI.

[0092] [PDCCH Monitoring Method 2]

[0093] For each of multiple QCLs, a common search space or a group common search space may also be set. The UE may also select the search space corresponding to the QCL set / indicated for PDCCH as the reception for DCI.

[0094] [PDCCH Monitoring Method 3]

[0095] For each of multiple QCLs, a common CORESET or a group common CORESET may also be set. The UE may also select the search space corresponding to the QCL set / indicated for PDCCH as the reception for DCI.

[0096] The UE detects DCI by monitoring a group scheduling search space set as a common search space or a group common search space.

[0097] The group scheduling search space may also vary depending on the QCL assumption. For example, the group scheduling search space may have different time-domain resources (symbols, time slots, etc.) depending on the QCL assumption.

[0098] The UE may also assume that the same DL data is scheduled in each PDCCH monitoring occasion (DCI within each PDCCH monitoring occasion) within the group scheduling search space.

[0099] The UE may also be set the group scheduling search space by higher-layer signaling.

[0100] In the present disclosure, UE-specific DCI can be scrambled by a cyclic redundancy check (CRC) using a UE-specific Radio Network Temporary Identifier (RNTI) (e.g., Cell (C-)RNTI), or can be scrambled by a UE-common RNTI. In addition, UE-specific DCI can also be scrambled by a RNTI dedicated to multicast / broadcast scheduling.

[0101] A single DCI for multiple UEs can also schedule DL data for multiple UEs. A single DCI can also schedule the same DL data in more than one multicast PDSCH. In the present disclosure, this single DCI can also be referred to as UE-common DCI.

[0102] DCI can be transmitted either in a common search space or in a group-common search space. The PDCCH monitoring occasion for DCI can also vary according to the Quasi-Co-Location (QCL) used in the UE. The UE can also select the PDCCH monitoring occasion based on multiple QCL assumptions.

[0103] A DL data can be either a codeword (CW) or a transport block (TB). The same DL data can have the same size (e.g., transport block size (TBS)), or can have different sizes.

[0104] It is also conceivable that the base station does not transmit DL data using multiple beams simultaneously.

[0105] In the present disclosure, UE-common DCI can be scrambled by a cyclic redundancy check (CRC) using a UE-specific RNTI (e.g., C-RNTI), or can be scrambled by a UE-common RNTI. In addition, UE-specific DCI can also be scrambled by a RNTI dedicated to multicast / broadcast scheduling.

[0106] In the present disclosure, the search space dedicated to multicast / broadcast scheduling can also be a group scheduling search space set as a common search space or a group-common search space.

[0107] <First Embodiment>

[0108] The multicast PDSCH may also not be retransmitted. In other words, the NW may also not retransmit the multicast PDSCH regardless of the success or failure of the reception processing (e.g., demodulation, decoding) of the multicast PDSCH by multiple UEs. In this case, the UE may also assume that the multicast PDSCH is not retransmitted and perform the reception processing of the multicast PDSCH.

[0109] In the case where the multicast PDSCH is not retransmitted, regarding the new data indicator (NDI) included in the downlink control information (DCI) (scheduling DCI, e.g., DCI format 1_0, 1_1) that schedules the multicast PDSCH, the UE may either assume that the value of the NDI field is a certain value (e.g., 1) or ignore the value of the NDI field. At this time, the UE may also determine that the multicast PDSCH is the first transmission (initial transmission) based on this certain value (e.g., 1). In addition, the UE may also perform the reception of the multicast PDSCH regardless of the value of the NDI field (without using the value of the NDI field).

[0110] In addition, in the case where the multicast is set for multiple UEs using higher layer signaling without retransmitting the multicast PDSCH, the NDI field may also not be included in the scheduling DCI of the multicast PDSCH. In other words, in the case where the multicast is set using higher layer signaling, multiple UEs may also receive the scheduling DCI of the multicast PDSCH that does not include the NDI field.

[0111] In addition, the NDI field may also not exist in the DCI format dedicated to the multicast PDSCH. In other words, multiple UEs may also receive the multicast PDSCH scheduled by the DCI format dedicated to the multicast PDSCH that does not include the NDI field.

[0112] In addition, the DCI scrambled by the RNTI dedicated to multicast scheduling may also not include the NDI field. In other words, in the case where the scheduling DCI of the multicast PDSCH is scrambled by the RNTI dedicated to multicast scheduling, multiple UEs may also receive the multicast PDSCH scheduled by this DCI format that does not include the NDI field.

[0113] At this time, the DCI scrambled by an RNTI other than the RNTI dedicated to multicast scheduling may either be a structure that includes the NDI field or a structure that does not include the NDI field.

[0114] In the case where the multicast PDSCH is not retransmitted, multiple UEs may also not send HARQ-ACK (at least one of ACK and NACK) for the multicast PDSCH.

[0115] As described above, according to the first embodiment, it is possible to reduce the PUCCH / PUSCH resources for HARQ-ACK transmission and the power consumption of the UE in the case where the multicast PDSCH is transmitted.

[0116] <Second Embodiment>

[0117] The multicast PDSCH may also be retransmitted using multicast / broadcast. In other words, the NW may also transmit one piece of data via the multicast PDSCH, and if the reception processing (e.g., demodulation, decoding) of the multicast PDSCH for any one of the multiple UEs fails, the one piece of data is retransmitted using multicast / broadcast. In this case, the UE may also assume that the data transmitted using the initially transmitted multicast PDSCH is retransmitted using multicast / broadcast, and perform the reception processing of the multicast PDSCH.

[0118] In addition, in the present disclosure, the multicast PDSCH retransmitted using multicast / broadcast may also be simply referred to as a retransmitted multicast PDSCH.

[0119] Furthermore, in the present disclosure, the initially transmitted multicast PDSCH may also be replaced with a first multicast PDSCH, an initially transmitted multicast PDSCH, etc. The retransmitted multicast PDSCH may also be replaced with a second multicast PDSCH.

[0120] Furthermore, in the present disclosure, the scheduling DCI of the initially transmitted multicast PDSCH may also be referred to as a first DCI. In addition, in the present disclosure, the scheduling DCI of the retransmitted multicast PDSCH may also be referred to as a second DCI. The first DCI and the second DCI may also be different DCIs from each other.

[0121] In the present disclosure, each of the first DCI and the second DCI may be either a UE-specific DCI or a DCI common to multiple UEs.

[0122] In the present disclosure, the search space for monitoring the UE-specific DCI may be either a common search space or a UE-specific search space. In addition, the search space for monitoring the UE-specific DCI may also be a search space dedicated to multicast / broadcast scheduling (or, a control resource set (CORESET)).

[0123] In the present disclosure, the search space for monitoring the UE-common DCI may be either a common search space or a UE-specific search space. In addition, the search space for monitoring the UE-common DCI may also be a search space dedicated to multicast / broadcast scheduling (or, a control resource set (CORESET)).

[0124] In this disclosure, the UE-specific DCI can be cyclic redundancy check (CRC) scrambled either by a UE-specific radio network temporary identifier (RNTI) (e.g., cell (C-)RNTI) or by a UE-common RNTI. In addition, the UE-specific DCI can also be CRC scrambled by an RNTI dedicated for multicast / broadcast scheduling.

[0125] In this disclosure, the UE-common DCI can be CRC scrambled either by a UE-specific RNTI (e.g., C-RNTI) or by a UE-common RNTI. This UE-common RNTI can also be a newly defined RNTI. In addition, the UE-specific DCI can also be CRC scrambled by an RNTI dedicated for multicast / broadcast scheduling.

[0126] "Embodiment 2-1"

[0127] Hereinafter, a case of scheduling a retransmission of a multicast PDSCH by a second DCI will be described.

[0128] When a retransmission of a multicast PDSCH is scheduled by a second DCI, the first DCI and the second DCI can also be associated. For example, at least one of the DCI format, RNTI, Control Channel Element (CCE) index / aggregation level of the physical downlink control channel (PDCCH) carrying the DCI, search space / Control Resource Set (CORESET) of the first DCI and the second DCI can also be common.

[0129] In addition, the new data indicator (NDI) fields of the first DCI and the second DCI can also be respectively restricted to a certain value. At this time, the value of the NDI field of the first DCI can also be N (e.g., 1). In addition, the value of the NDI field of the second DCI can also be M (e.g., 0). The value of the NDI field of the first DCI and the value of the NDI field of the second DCI can also be different from each other.

[0130] Figure 1 is a diagram showing an example of the retransmission process of the multicast PDSCH. In Figure 1Among them, multiple UEs (UE1 and UE2) receive the multicast PDSCH1 scheduled by DCI1. This multicast PDSCH1 is a PDSCH carrying a DL data (which can also be simply referred to as data). UE1 that successfully processes the reception of this PDSCH1 uses PUCCH1 to send an affirmative response (HARQ-ACK, or simply ACK), and UE2 that fails to process the reception of this PDSCH uses PUCCH2 to send a negative response (HARQ-NACK, or simply NACK). Thereafter, the UE receives the multicast PDSCH2 scheduled by DCI2. This multicast PDSCH2 is a PDSCH carrying the same data as the data carried by the multicast PDSCH1.

[0131] In addition, Figure 1 The number of UEs, the number of DCIs, PDSCHs, PUCCH resources, and the allocation positions of time / frequency shown are just examples and are not limited to this example. In addition, Figure 1 DCI1 and DCI2 in it can be either UE-common DCIs or UE-specific DCIs. In addition, the resources for sending HARQ-ACK for the multicast PDSCH can be either UE-common resources for sending HARQ-ACK or PUSCH resources.

[0132] In addition, in the following figures shown in this disclosure, the initially transmitted multicast PDSCH and the retransmitted multicast PDSCH can also be PDSCHs carrying the same DL data. In addition, the repeated transmission of the multicast PDSCH can also be a multicast PDSCH carrying the same DL data.

[0133] A UE that successfully processes the reception of the multicast PDSCH (the UE that has sent ACK for the multicast PDSCH) may not be requested to monitor the second DCI. In addition, a UE that successfully processes the reception of the multicast PDSCH may neither be requested to re-receive the multicast PDSCH nor send HARQ-ACK information for the multicast PDSCH.

[0134] In this case, this UE may also not send HARQ-ACK for the retransmitted multicast PDSCH. In addition, this UE may also send ACK for the retransmitted multicast PDSCH regardless of the reception result of the retransmitted multicast PDSCH. Thereby, the NW's HARQ-ACK reception error can be avoided.

[0135] A UE that fails to process the reception of the multicast PDSCH (the UE that has sent NACK for the multicast PDSCH) may also monitor the second DCI and perform the reception of the retransmitted multicast PDSCH.

[0136] In this case, the UE can also send ACK / NACK based on the reception result of the retransmitted multicast PDSCH. In addition, when the upper limit value of the number of retransmissions of the multicast PDSCH, which is predefined / set in advance, is reached, the UE may not send ACK / NACK for the multicast PDSCH. The upper limit value of the number of retransmissions of the multicast PDSCH can be predefined in the specification in advance or can be set for the UE by higher layer signaling.

[0137] "Embodiment 2-2"

[0138] Hereinafter, a case where the retransmission of the multicast PDSCH is scheduled by the DCI (first DCI) that schedules the initial transmission of the multicast PDSCH will be described.

[0139] When the retransmitted multicast PDSCH is transmitted by multicast, the DCI (first DCI) that schedules the initial transmission of the multicast PDSCH can also schedule the retransmitted multicast PDSCH. In other words, the UE can also receive the initial transmission multicast PDSCH and the retransmitted multicast PDSCH that are scheduled by one scheduling DCI. As a result, the overhead of the scheduling DCI for receiving the retransmitted multicast PDSCH can be reduced.

[0140] In this case, the UE can send HARQ-ACK information for the initial transmission multicast PDSCH either regardless of the reception result of the initial transmission multicast PDSCH or may not send HARQ-ACK information for the initial transmission multicast PDSCH.

[0141] In addition, in the present disclosure, the retransmitted multicast PDSCH can be transmitted once or multiple times. In addition, the upper limit value (maximum number) of the number of retransmissions of the multicast PDSCH can be predefined in the specification in advance, can be set for the UE by higher layer signaling, or can be a value reported to the NW through UE capability information (UE Capability).

[0142] In this case, the value of the NDI field included in the first DCI can also be a certain value (for example, 1). In addition, when multicast is set for multiple UEs, the UE can also assume (replace) the value of the NDI field included in the first DCI with a certain value (for example, 1) and receive the multicast PDSCH. In addition, the value of the NDI field included in the first DCI may not exist.

[0143] Figure 2 It is a diagram showing another example of the retransmission process of the multicast PDSCH. In Figure 2 , multiple UEs (UE1 and UE2) receive the multicast PDSCH1 scheduled by DCI1. In Figure 2Among them, the UE1 for which the reception process of the PDSCH1 is successful uses PUCCH1 to send an affirmative response (HARQ-ACK, or simply ACK), and the UE2 for which the reception process of the PDSCH fails uses PUCCH2 to send a negative response (HARQ-NACK, or simply NACK), but the ACK / NACK may not be sent either. Thereafter, the UE receives the multicast-utilized PDSCH2 scheduled by DCI1.

[0144] In addition, Figure 2 The number of UEs, the number of DCI, PDSCH, and PUCCH resources, and the allocation positions of time / frequency shown are merely examples and are not limited to this example. In addition, Figure 2 The DCI1 in can be either UE-common DCI or UE-dedicated DCI. In addition, the resources for HARQ-ACK transmission for the multicast PDSCH can be either UE-common resources for HARQ-ACK transmission or PUSCH resources.

[0145] A UE for which the reception process of the multicast PDSCH is successful (the UE that has sent ACK for the multicast PDSCH) may not be requested to retransmit the reception of the multicast PDSCH, nor may it send HARQ-ACK information for the multicast PDSCH.

[0146] In this case, the UE may also not send HARQ-ACK for the retransmitted multicast PDSCH. In addition, the UE may also send ACK for the retransmitted multicast PDSCH regardless of the reception result of the retransmitted multicast PDSCH.

[0147] A UE for which the reception process of the multicast PDSCH fails (the UE that has sent NACK for the multicast PDSCH) may also perform the reception of the retransmitted multicast PDSCH.

[0148] In this case, the UE may also perform the transmission of ACK / NACK based on the reception result of the retransmitted multicast PDSCH. In addition, when the upper limit value of the number of retransmissions of the multicast PDSCH reaches the predefined / set value, the ACK / NACK for the multicast PDSCH may not be sent either. The upper limit value of the number of retransmissions of the multicast PDSCH can be either predefined in the specification or set for the UE by higher layer signaling.

[0149] Hereinafter, the resource indication of the retransmitted multicast PDSCH based on the scheduling DCI of the initial transmission of the multicast PDSCH will be described. The UE may also receive the information related to the resources of the retransmitted multicast PDSCH included in the scheduling DCI of the initial transmission of the multicast PDSCH.

[0150] In the case where the scheduling DCI for the initial transmission of the multicast PDSCH is used to schedule the retransmission of the multicast PDSCH, the DCI field for resource indication of the multicast PDSCH can also be extended.

[0151] Specifically, the correspondence relationship (table) between the DCI code point and at least one of the time domain resource allocation (TDRA) and frequency domain resource allocation (FDRA) of the multicast PDSCH applied in each of the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH is notified / stipulated to the UE, and the UE can also determine the resources of the initial transmission / retransmission of the multicast PDSCH based on the DCI code point included in the scheduling DCI. This correspondence relationship (table) can be either stipulated in the specification in advance or notified to the UE through higher layer signaling.

[0152] Figure 3A FIG. is an example showing DCI-based resource indication of the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH. In Figure 3A a table (DCI field 1) for determining the resources of the initial transmission of the multicast PDSCH and a table (DCI field 2) for determining the resources of the retransmission of the multicast PDSCH are notified / set to the UE. The UE uses the PDSCH resources corresponding to the value corresponding to the first DCI code point notified by the scheduling DCI among the PDSCH resources shown in DCI field 1 to receive the initial transmission of the multicast PDSCH. In addition, the UE uses the PDSCH resources corresponding to the value corresponding to the second DCI code point notified by the scheduling DCI among the PDSCH resources shown in DCI field 2 to receive the retransmission of the multicast PDSCH. The value corresponding to each DCI code point can also be associated with the TDRA / FDRA field of the multicast PDSCH.

[0153] In addition, Figure 3A each of the tables shown is merely an example, and the DCI code point and the value corresponding to the code point are not limited to this.

[0154] Furthermore, in the case where the scheduling DCI for the initial transmission of the multicast PDSCH is used to schedule the retransmission of the multicast PDSCH, the DCI field for resource indication of the multicast PDSCH can also be extended. In other words, the UE can also use the resources of the initial transmission and retransmission of the multicast PDSCH corresponding to one DCI code point to receive the initial transmission / retransmission of the multicast PDSCH.

[0155] Specifically, the correspondence relationship (table) between the DCI code point and the TDRA / FDRA field of the multicast PDSCH applied in the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH is notified / stipulated to the UE, and the UE can also determine the resources for the initial transmission and retransmission of the multicast PDSCH based on a DCI code point included in the scheduling DCI. In this case, the time / frequency resources for the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH can be the same or different.

[0156] Figure 3B is a diagram showing an example of DCI-based resource indication for the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH. In Figure 3B a table (DCI field 1) for determining the resources for the initial transmission and retransmission of the multicast PDSCH is notified / set to the UE. The UE uses the PDSCH resource corresponding to the value corresponding to the DCI code point notified by the scheduling DCI in the PDSCH resources shown in DCI field 1 to receive the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH. The value corresponding to each DCI code point can also be associated with the TDRA / FDRA field of the multicast PDSCH.

[0157] In addition, Figure 3B the tables shown are just examples, and the DCI code point and the value corresponding to this code point are not limited to this.

[0158] Furthermore, in the case of using the scheduling DCI of the initial transmission of the multicast PDSCH to schedule the retransmission of the multicast PDSCH, the UE can also determine the time / frequency resources for the retransmission of the multicast PDSCH based on the offset value relative to the time / frequency resources of the initial transmission of the multicast PDSCH notified (set) by the scheduling DCI.

[0159] This offset value can be either stipulated in the specification in advance or notified to the UE through high-layer signaling.

[0160] Figure 3C is a diagram showing an example of DCI-based resource indication for the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH. The UE is notified / stipulated of the time offset value (K) from the resource of the initial transmission of the multicast PDSCH (multicast PDSCH1) to the resource of the retransmission of the multicast PDSCH (multicast PDSCH2), and receives the retransmission of the multicast PDSCH based on this offset value. In Figure 3C the UE uses the same frequency resource as multicast PDSCH1 to receive multicast PDSCH2 after K time slots from the multicast PDSCH1 resource.

[0161] In addition, Figure 3CThe example shown is just one example. The time offset can also be the time from the start or end of the initial transmission of the multicast PDSCH resource to the start or end of the retransmission of the multicast PDSCH resource, represented by time slots / symbols.

[0162] In addition, in Figure 3C the example shown, the case where the time offset is notified / set to the UE is shown. However, either the frequency offset can be notified / set to the UE, or both the time offset and the frequency offset can be notified / set to the UE.

[0163] This frequency offset can also be the value from the minimum / maximum / average physical resource block (PRB) of the initial transmission of the multicast PDSCH resource to the minimum / maximum / average PRB of the retransmission of the multicast PDSCH resource.

[0164] In the case where multiple retransmissions of the multicast PDSCH are set, the time / frequency offset value of each retransmitted multicast PDSCH resource relative to the initial transmission of the multicast PDSCH resource can also be notified / set to the UE. In addition, in the case where multiple retransmissions of the multicast PDSCH are set, the time / frequency offset value of the retransmitted multicast PDSCH resource relative to the previous multicast PDSCH resource can also be notified / set to the UE. The offset value in this case can be either one or a certain quantity (for example, the number of retransmitted multicast PDSCHs set) notified / set to the UE.

[0165] Hereinafter, the following method will be described: using the scheduling DCI of the initial transmission of the multicast PDSCH to indicate at least one of the timing from the PDSCH to the HARQ feedback (PDSCH-to-HARQ_ feedback timing indicator, HARQ feedback timing) and the resource for HARQ-ACK transmission in the case of scheduling the retransmission of the multicast PDSCH.

[0166] In the case of using the scheduling DCI of the initial transmission of the multicast PDSCH to schedule the retransmission of the multicast PDSCH, a specific field (HARQ feedback timing indicator field / other field) can also be included in this scheduling DCI. The other field can also be a field for indicating the resource for HARQ-ACK transmission.

[0167] Specifically, the correspondence relationship (table) between the DCI code points of specific fields applied in each of the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH and the HARQ feedback timing / HARQ-ACK transmission resource for the multicast PDSCH can also be notified / specified to the UE, and based on the DCI code point included in the scheduling DCI, the HARQ feedback timing / HARQ-ACK transmission resource for the initial transmission / retransmission of the multicast PDSCH is determined. This correspondence relationship (table) can be either pre-specified in the specification or notified to the UE through higher layer signaling.

[0168] Figure 4A FIG. is an example of a method for determining the HARQ feedback timing / HARQ-ACK transmission resource for the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH. In Figure 4A the table (DCI field 1) of the HARQ feedback timing / HARQ-ACK transmission resource for determining the HARQ-ACK for the initial transmission of the multicast PDSCH and the table (DCI field 2) of the HARQ feedback timing / HARQ-ACK transmission resource for determining the HARQ-ACK for the retransmission of the multicast PDSCH are notified / set to the UE.

[0169] In Figure 4A the UE uses the HARQ feedback timing / HARQ-ACK transmission resource corresponding to the value corresponding to the first DCI code point notified by the scheduling DCI in the HARQ feedback timing / HARQ-ACK transmission resource indicated by DCI field 1 to send the HARQ-ACK for the initial transmission of the multicast PDSCH. In addition, the UE uses the HARQ feedback timing / HARQ-ACK transmission resource corresponding to the value corresponding to the second DCI code point notified by the scheduling DCI in the HARQ feedback timing / HARQ-ACK transmission resource indicated by DCI field 2 to send the HARQ-ACK for the retransmission of the multicast PDSCH. The value corresponding to each DCI code point can also be associated with the HARQ feedback timing / HARQ-ACK transmission resource for the initial transmission / retransmission of the multicast PDSCH.

[0170] In addition, Figure 4A each of the tables shown is merely an example, and the DCI code point and the value corresponding to the code point are not limited thereto.

[0171] In addition, in the case where the scheduling DCI for the initial transmission of the multicast PDSCH is used to schedule the retransmission of the multicast PDSCH, one DCI field for indicating the HARQ feedback timing for the multicast PDSCH and the resources for HARQ-ACK transmission may also be included in this scheduling DCI. In other words, the UE can also use the HARQ feedback timing and the resources for HARQ-ACK transmission corresponding to one DCI code point for both the initial transmission and the retransmission of the multicast PDSCH to send the HARQ-ACK for the initial transmission and the retransmission of the multicast PDSCH.

[0172] Specifically, the correspondence relationship (table) between the DCI code point and the HARQ feedback timing / HARQ-ACK transmission resources for the HARQ-ACK of the multicast PDSCH applied in the initial transmission and the retransmission of the multicast PDSCH is notified / stipulated to the UE, and the UE can also determine the HARQ feedback timing / HARQ-ACK transmission resources for the HARQ-ACK of the initial transmission and the retransmission of the multicast PDSCH based on one DCI code point included in the scheduling DCI. In this case, the HARQ feedback timing / HARQ-ACK transmission resources for the HARQ-ACK of the initial transmission and the retransmission of the multicast PDSCH may be the same or different.

[0173] Figure 4B is a diagram showing an example of a method for determining the HARQ feedback timing / HARQ-ACK transmission resources for the initial transmission and the retransmission of the multicast PDSCH. In Figure 4B a table (DCI field 1) for determining the HARQ feedback timing / HARQ-ACK transmission resources for the initial transmission and the retransmission of the multicast PDSCH is notified / set to the UE. The UE uses the HARQ feedback timing / HARQ-ACK transmission resources corresponding to the value associated with the DCI code point notified by the scheduling DCI in the HARQ feedback timing / HARQ-ACK transmission resources shown in DCI field 1 to send the HARQ-ACK for the initial transmission and the retransmission of the multicast PDSCH. The value corresponding to each DCI code point may also be associated with the HARQ feedback timing / HARQ-ACK transmission resources for the HARQ-ACK of the multicast PDSCH.

[0174] In addition, Figure 4B each of the tables shown is merely an example, and the DCI code point and the value corresponding to this code point are not limited to this.

[0175] In addition, in the case of using the scheduling DCI for the initial transmission of the multicast PDSCH to schedule the retransmission of the multicast PDSCH, the UE can also determine the HARQ-ACK transmission resource for the retransmitted multicast PDSCH based on the offset value with respect to the HARQ-ACK transmission resource for the (set) initial transmission of the multicast PDSCH notified by the scheduling DCI.

[0176] This offset value can either be pre-specified in the specification or be notified to the UE via higher-layer signaling.

[0177] Figure 4C It is a diagram showing an example of the method for determining the HARQ-ACK transmission resources for the initial transmission of the multicast PDSCH and the retransmission of the multicast PDSCH. The UE is notified / specified of the time offset value (K) from the HARQ-ACK transmission resource (PUCCH1) for the initial transmission of the multicast PDSCH to the HARQ-ACK transmission resource (PUCCH2) for the retransmission of the multicast PDSCH, and based on this offset value, performs the transmission of HARQ-ACK for the initial transmission and the retransmission of the multicast PDSCH. In Figure 4C it, starting from PUCCH1, after K time slots, the UE uses the same frequency resource as PUCCH1 to transmit PUCCH2.

[0178] In addition, Figure 4C The example shown is just one example, and the time offset can also represent the time from the start or end of the HARQ-ACK transmission resource for the initial transmission of the multicast PDSCH to the start or end of the HARQ-ACK transmission resource for the retransmission of the multicast PDSCH in terms of time slots / symbols.

[0179] In addition, in Figure 4C the example shown, the case where the time offset is notified / set to the UE is shown, but it can be either that the frequency offset is notified / set to the UE or that both the time offset and the frequency offset are notified / set to the UE.

[0180] This frequency offset can also be the value from the minimum / maximum / average PRB of the HARQ-ACK transmission resource for the initial transmission of the multicast PDSCH to the minimum / maximum / average PRB of the HARQ-ACK transmission resource for the retransmission of the multicast PDSCH.

[0181] In the case where multiple retransmission multicast PDSCHs are configured, the time / frequency offset value of the HARQ-ACK transmission resource for each retransmission multicast PDSCH with respect to the HARQ-ACK transmission resource for the initial transmission multicast PDSCH may also be notified / set to the UE. In addition, in the case where multiple retransmission multicast PDSCHs are configured, the time / frequency offset value of the HARQ-ACK transmission resource for the retransmission multicast PDSCH with respect to the HARQ-ACK transmission resource for the previous multicast PDSCH may also be notified / set to the UE. The offset value in this case may be either one or a certain quantity (e.g., the number of configured retransmission multicast PDSCHs) notified / set to the UE.

[0182] As described above, according to the second embodiment, even when the number of UEs that require retransmission of the multicast PDSCH is large, retransmission can be performed using fewer PDSCH resources, and the resource utilization efficiency can be improved.

[0183] <Third Embodiment>

[0184] The multicast PDSCH may also be retransmitted using unicast. In other words, the NW may also transmit one piece of data via the multicast PDSCH, and if the reception processing (e.g., demodulation, decoding) of any one multicast PDSCH for multiple UEs fails, the one piece of data is retransmitted using unicast. In this case, the UE may also assume that the multicast PDSCH is retransmitted using unicast and perform the reception processing of the multicast PDSCH.

[0185] In addition, in the present disclosure, unicast may also mean being specifically transmitted for the UE according to the method defined in Rel.15, 16.

[0186] In the present embodiment, the first DCI and the second DCI may also be restricted. For example, the first DCI may be either a DCI dedicated to multicast / broadcast, or a DCI to which a DCI format dedicated to multicast / broadcast is applied, or a DCI whose CRC is scrambled by a multicast / broadcast dedicated RNTI. In addition, the second DCI may be either a DCI used in unicast (defined in Rel.15 / 16), or a DCI to which a DCI format used in unicast is applied, or a DCI whose CRC is scrambled by an RNTI used in unicast. In addition, the second DCI may be either a DCI dedicated to multicast / broadcast, or a DCI to which a DCI format dedicated to multicast / broadcast is applied, or a DCI whose CRC is scrambled by a multicast / broadcast dedicated RNTI.

[0187] In the present disclosure, the DCI format for multicast may also be at least one of a DCI format dedicated to multicast / broadcast and a DCI format applied to a DCI scrambled by a CRC using a multicast / broadcast dedicated RNTI.

[0188] In addition, in the present disclosure, the DCI for unicast may also be at least one of a DCI applied to a DCI format defined in Rel.15 / 16 and a DCI scrambled by a CRC using an RNTI defined in Rel.15 / 16.

[0189] In addition, for example, between a first DCI and a second DCI, at least one of the DCI format, RNTI, the control channel element (Control Channel Element (CCE)) index / aggregation level of the PDCCH carrying the DCI, and the search space / control resource set (Control Resource Set (CORESET)) may also be correlated with each other.

[0190] In addition, the NDI fields of the first DCI and the second DCI may also be respectively restricted to a certain value. At this time, the value of the NDI field of the first DCI may be N (for example, 1). In addition, the value of the NDI field of the second DCI may be M (for example, 0). The value of the NDI field of the first DCI and the value of the NDI field of the second DCI may also be different from each other.

[0191] Figure 5 is a diagram showing an example of the retransmission process of the multicast PDSCH. In Figure 5 multiple UEs (UE1 and UE2) receive the multicast PDSCH1 scheduled by DCI1. UE1 that successfully receives the PDSCH1 uses PUCCH1 to send ACK, and UE2 that fails to receive the PDSCH uses PUCCH2 to send NACK. Thereafter, the UE receives the unicast PDSCH2 scheduled by DCI2.

[0192] In addition, Figure 5 The number of UEs, the number of DCIs, PDSCHs, PUCCH resources, and the allocation positions of time / frequency shown are merely examples and are not limited to this example. In addition, Figure 5 DCI1 and DCI2 in

[0193] The first DCI and the second DCI may also be applied with different DCI formats. Specifically, the first DCI may also be applied with a DCI format for multicast / broadcast. In addition, the second DCI may also be applied with a DCI format for unicast.

[0194] In addition, the first DCI format may also be a DCI format specified in Rel.15 / 16. In this case, the UE may also replace a specific field in the fields included in the DCI format specified in Rel.15 / 16 with a parameter for multicast and receive the multicast PDSCH.

[0195] At this time, when the HARQ process ID included in each of the first DCI and the second DCI is the same and the value of the NDI field is different (or the same), the UE may also determine that the initial transmission multicast PDSCH scheduled by the first DCI and the retransmission multicast PDSCH scheduled by the second DCI carry the same data.

[0196] In addition, the same (common) DCI format may also be applied to the first DCI and the second DCI. Specifically, the first DCI and the second DCI may also be applied with a DCI format for multicast / broadcast.

[0197] At this time, when the HARQ process ID included in each of the first DCI and the second DCI is the same and the value of the NDI field is different (or the same), the UE may also determine that the initial transmission multicast PDSCH scheduled by the first DCI and the retransmission multicast PDSCH scheduled by the second DCI carry the same data.

[0198] In this case, the following field may also be specified / set in the DCI for multicast / broadcast, and this field is used to notify the UE whether the DCI schedules the multicast PDSCH or the unicast PDSCH.

[0199] This field may also be the first bit of the DCI for multicast / broadcast, and the UE may use the subsequent bits as a unicast field or a multicast field based on this first bit.

[0200] In addition, in this case, regarding whether the DCI for multicast / broadcast schedules the multicast PDSCH or the unicast PDSCH, the UE may also implicitly determine based on a specific field value included in the DCI and the rules applied to this specific field value.

[0201] By making the DCI formats applied to the first DCI and the second DCI the same, UEs that do not need to receive the retransmission multicast PDSCH (for example, UEs that have successfully received the initial transmission multicast PDSCH) do not receive the retransmission multicast PDSCH, and overhead can be suppressed.

[0202] Regardless of the similarities and differences between the first DCI and the second DCI, the DCI resource for UE-specific / UE-common retransmission (at least one of search space, CORESET, and monitoring opportunity) can also be set for the UE. The UE can also use this DCI resource for retransmission to monitor the second DCI.

[0203] UEs that have successfully received and processed the multicast PDSCH (UEs that have sent ACK for the multicast PDSCH) may not be requested to monitor the second DCI. In addition, UEs that have successfully received and processed the multicast PDSCH may not be requested to retransmit the reception of the multicast PDSCH, nor may they send HARQ-ACK information for the multicast PDSCH.

[0204] In this case, the UE may also not send HARQ-ACK information for the retransmitted multicast PDSCH. In addition, the UE may send HARQ-ACK information indicating ACK for the retransmitted multicast PDSCH regardless of the reception result of the retransmitted multicast PDSCH.

[0205] UEs that have failed to receive and process the multicast PDSCH (UEs that have sent NACK for the multicast PDSCH) may also monitor the second DCI and retransmit the reception of the multicast PDSCH.

[0206] In this case, the UE may also send ACK / NACK based on the reception result of the retransmitted multicast PDSCH. In addition, when the upper limit value (maximum number) of the retransmission times of the multicast PDSCH reaches the pre-specified / set value, ACK / NACK for the multicast PDSCH may not be sent. The upper limit value of the retransmission times of the multicast PDSCH may be pre-specified in the specification or set for the UE through higher layer signaling.

[0207] As described above, according to the third embodiment, even when the number of UEs that need to retransmit the multicast PDSCH is small, the NW can perform the minimum required data transmission, improving the resource utilization efficiency.

[0208] <Fourth Embodiment>

[0209] When applying the above second - third embodiments, it is assumed that the DCI (second DCI) for scheduling the retransmission of the multicast PDSCH is notified before the determination of the reception result of the initial transmission of the multicast PDSCH (HARQ determination) ( Figure 6 ). In this case, at the reception time of the second DCI, the NW and the UE cannot identify whether the initial transmission of the multicast PDSCH has been correctly received by the UE.

[0210] In addition, if the second DCI is always received after the transmission of the HARQ-ACK corresponding to the initial transmission of the multicast PDSCH, there is a concern that the delay until retransmission completion becomes large.

[0211] Hereinafter, in the present embodiment, a method for controlling the reception timing of an appropriate second DCI will be described.

[0212] The UE may also assume that the second DCI is transmitted after a specific time. Specifically, the UE may receive (may assume reception of) the second DCI after a specific time after the reception of the initial transmission of the multicast PDSCH.

[0213] This specific time may also be determined based on the HARQ-ACK process time. This specific time may also be the time after the passage of the HARQ-ACK process time after the reception of the multicast PDSCH. In the present disclosure, this HARQ-ACK process time may also be the minimum time from the PDSCH reception to the HARQ transmission (PDSCH to HARQ transmission). This HARQ-ACK process time may be specified in the specification, may be set by higher layer signaling, or may be reported from the UE through UE capability information.

[0214] In addition, this specific time may be an integer multiple (M times) of a certain time resource (for example, a symbol, a time slot, a sub-time slot), or may be Tms (T is an arbitrary value). The values M and T may also be determined based on the HARQ-ACK process time. In addition, the above values M and T may be specified in the specification in advance, may be set for the UE by higher layer signaling, or may be values reported to the NW through UE capability information (UE Capability).

[0215] Thereby, it is possible to control the retransmission of the multicast PDSCH by the UE considering the HARQ-ACK detection of the initial transmission of the multicast PDSCH.

[0216] In addition, in the present disclosure, this specific time may also be a time / offset notified by higher layer signaling. In addition, this specific time may also be the time obtained by adding / subtracting the time / offset notified by higher layer signaling to / from the above HARQ-ACK process time.

[0217] Figure 7 It is a diagram showing an example of the reception timing of the DCI for scheduling the retransmission of the multicast PDSCH. In Figure 7Among them, multiple UEs receive the initially transmitted multicast PDSCH (multicast PDSCH1) scheduled by DCI1. Thereafter, the UE receives the retransmitted multicast PDSCH (multicast PDSCH2) scheduled by DCI2.

[0218] In Figure 7 among them, the UE receives DCI2 after the HARQ-ACK processing time of multicast PDSCH1. In other words, the UE does not assume to receive DCI2 before the HARQ-ACK processing time of multicast PDSCH1.

[0219] In addition, Figure 7 the number of the DCI, PDSCH, and PUCCH resources shown and the allocated positions in terms of time / frequency are merely examples and are not limited to this example. In addition, Figure 7 DCI1 and DCI2 in

[0220] can be either UE-common DCI or UE-specific DCI. The UE can also switch the monitoring (receiving, detecting) operation of the second DCI based on whether the monitoring period of the second DCI is before or after a specific time. In addition, this specific time can also be the HARQ processing time. In addition, the monitoring period of the DCI can also be replaced with the measurement time of the DCI, the detection time of the DCI, the search space / CORESET / monitoring opportunity set for monitoring the DCI, the receiving period of the DCI, etc.

[0221] When the reception timing of the second DCI is before a specific time, the UE can also measure the second DCI and perform blind detection. When the reception timing of the second DCI is after a specific time, the UE can also decide whether to perform blind detection of the second DCI based on the reception processing result of the initially transmitted multicast PDSCH.

[0222] In this case, the UE can also not perform blind detection of the second DCI when the reception processing of the initially transmitted multicast PDSCH is successful, and perform blind detection of the second DCI when the reception processing of the initially transmitted multicast PDSCH fails ( Figure 8 ).

[0223] In addition, in Figure 8 the example shown, regarding the resources of DCI1 (at least one of the search space, CORESET, and monitoring opportunity) and the resources of DCI2, the UE can also be notified by higher-layer signaling. Thereby, the UE recognizes that the DCI resources for the initial transmission and the DCI resources for the retransmission are different, and can appropriately perform the reception control of the DCI for the initial transmission / retransmission.

[0224] As described above, according to the fourth embodiment, it is possible to perform reception control of flexible retransmission of multicast PDSCH by the UE regardless of the reception timing of the DCI for scheduling retransmission of the multicast PDSCH.

[0225] <Fifth Embodiment>

[0226] In this embodiment, a case where the multicast PDSCH is repeatedly transmitted (repetition) by one DCI will be described.

[0227] In this embodiment, the HARQ process ID of each multicast PDSCH may also be the same. In addition, the redundancy version (RV) of each multicast PDSCH may be the same or may be changed based on a specific rule.

[0228] The number of repetitions of this multicast PDSCH may be specified in the specification in advance, may be notified (set) to the UE by higher layer signaling, or may be a value reported to the NW through the UE capability information (UE Capability) of the UE. In addition, the UE may use the set value when the number of repetitions of this multicast PDSCH is set to the UE by the NW, or may use a specific value (for example, 4) when not set to the UE by the NW.

[0229] Figure 9 is a diagram showing an example of repeated transmission of the multicast PDSCH. In Figure 9 , the UE receives repeated transmission of the multicast PDSCH (multicast PDSCH1 - 4) scheduled by one scheduling DCI (DCI1). In Figure 9 , the number of repetitions of the multicast PDSCH is 4.

[0230] In addition, Figure 9 The number of repetitions, the number of DCI and PDSCH resources, and the allocation positions in time / frequency shown are just examples and are not limited to this example. In addition, Figure 9 DCI1 in

[0231] is respectively illustrated as a DCI common to the UE, but may also be a DCI dedicated to the UE.

[0232] Candidates for the time / frequency resources of each multicast PDSCH can also be set for multiple UEs by higher-layer signaling. Then, the UE can also determine the time / frequency resources of each multicast PDSCH from among the multiple candidates based on specific fields (e.g., TDRA / FDRA fields) included in the scheduling DCI of the multicast PDSCH.

[0233] In addition, a time / frequency offset value for the time / frequency resources of a specific multicast PDSCH among multiple multicast PDSCHs is notified to the UE, and the UE can also determine the time / frequency resources of multicast PDSCHs other than the specific multicast PDSCH based on this offset value. The scheduling DCI can also indicate the time / frequency resources of the specific multicast PDSCH.

[0234] In addition, the specific multicast PDSCH can be either the first multicast PDSCH transmitted among the multiple multicast PDSCHs or the previous multicast PDSCH transmitted among the multiple multicast PDSCHs.

[0235] Figure 10 is a diagram showing an example of the repeated transmission of a multicast PDSCH. In Figure 10 , the UE receives repeated transmissions (multicast PDSCH1-4) of a multicast PDSCH scheduled by one scheduling DCI (DCI1). In Figure 10 , the number of repetitions of the multicast PDSCH is 4.

[0236] In Figure 10 In the example shown, a frequency offset value relative to the previous multicast PDSCH is notified to the UE, and the UE receives multiple multicast PDSCHs based on this offset value.

[0237] In addition, Figure 10 The number of repetitions, the DCI, and the number of PDSCH resources, and the time / frequency allocation positions shown in Figure 10 are merely examples and are not limited to this example. In addition,

[0238] In the repeated transmission of a multicast PDSCH, the TCI state applied to each multicast PDSCH can also be different. In other words, the UE can also use different spatial domain filters to receive each multicast PDSCH. By having different TCI states applied to each multicast PDSCH, a spatial diversity effect can be obtained.

[0239] Candidates for the TCI states applied in each multicast PDSCH may also be set for multiple UEs by higher layer signaling. Subsequently, the UE may also determine, based on a specific field included in the scheduling DCI of the multicast PDSCH, the TCI state to be applied in each multicast PDSCH from among the multiple candidates.

[0240] In addition, the UE may also determine the TCI state to be applied in each multicast PDSCH based on specific rules (beam circle, beam circling). The list of the multiple TCI states for beam circling may be either predefined in the specification or notified (set) to the UE by higher layer signaling. In addition, the TCI state applied in the first multicast PDSCH (initial TCI state) may also be notified to the UE.

[0241] Beam circle (beam period) may also be that a list of multiple TCI states is cyclically applied to multiple signals / channels (e.g., PDSCH).

[0242] Figure 11 is a diagram showing an example of repeated transmission of the multicast PDSCH. In Figure 11 , the UE receives repeated transmissions (multicast PDSCH1 - 4) of the multicast PDSCH scheduled by one scheduling DCI (DCI1). In Figure 11 , the number of repetitions of the multicast PDSCH is 4.

[0243] In Figure 11 the example shown, as the beam, the order of TCI state #1, TCI state #2, TCI state #3, and TCI state #4 is set for the UE and it is notified that TCI state #1 is applied to the first multicast PDSCH. Based on this cycle and the initial TCI state, the UE receives multiple multicast PDSCHs.

[0244] In addition, Figure 11 the number of repetitions, the number of DCI and PDSCH resources, the time / frequency allocation location, the TCI state, the cycle of the TCI state, and the initial TCI state shown are merely examples and are not limited to this example. In addition, Figure 11 DCI1 in

[0245] is respectively illustrated as DCI common to UEs, but it may also be DCI dedicated to a UE.

[0246] The UE may also not transmit HARQ - ACK for the repeated transmission of the multicast PDSCH.

[0247] In addition, the UE may also send HARQ-ACKs for repeated transmissions of the multicast PDSCH.

[0248] For example, the UE may also use PUCCH / PUSCH resources for one HARQ-ACK transmission to send HARQ-ACKs for repeated transmissions of the multicast PDSCH. In this case, when the reception process of at least one of each multicast PDSCH is successful, the UE may also send an ACK. In addition, when the reception processes of all of each multicast PDSCH fail, the UE may also send a NACK.

[0249] In this case, the PUCCH / PUSCH resources for HARQ-ACK transmission may also be allocated after the last symbol of the last multicast PDSCH.

[0250] Figure 12 It is a diagram showing an example of HARQ-ACK transmission for repeated transmissions of the multicast PDSCH. Figure 12 The scheduling DCI and the structure of each multicast PDSCH shown are the same as Figure 9 those. The UE uses PUCCH resources to send HARQ-ACKs (ACK / NACK) for repeated transmissions of the multicast PDSCH.

[0251] In addition, Figure 12 The number of repetitions, DCI, PDSCH, the number of PUCCH resources, and the time / frequency allocation positions shown are just examples and are not limited to this example. In addition, Figure 12 The DCI1s in Figure 12 are each illustrated as UE-common DCI, but may also be UE-dedicated DCI. In addition,

[0252] In addition, for example, the UE may also use PUCCH / PUSCH resources for HARQ-ACK transmission set for each multicast PDSCH to send HARQ-ACKs for repeated transmissions of the multicast PDSCH.

[0253] In this case, the UE may also perform the reception process of each multicast PDSCH and use the HARQ-ACK transmission resources corresponding to the multicast PDSCH to send an ACK corresponding to the first multicast PDSCH with a successful reception process.

[0254] On the other hand, the UE can also perform the reception processing of each multicast PDSCH and does not send the HARQ-ACK corresponding to the multicast PDSCH for which the reception processing fails. In addition, the UE can also perform the reception processing of each multicast PDSCH and use the HARQ-ACK transmission resource corresponding to the multicast PDSCH to send the NACK corresponding to the multicast PDSCH for which the reception processing fails.

[0255] In the case where the reception processing of at least one multicast PDSCH is successful, the UE can also not send the HARQ-ACK for the multicast PDSCH received after the multicast PDSCH whose initial reception processing is successful. Thereby, unnecessary power consumption of the UE can be avoided.

[0256] In addition, in the case where the reception processing of at least one multicast PDSCH is successful, the UE can also send an ACK for the subsequent multicast PDSCH (subsequent multicast PDSCH) received after the multicast PDSCH whose initial reception processing is successful in a manner independent of the reception processing result of the subsequent multicast PDSCH. Thereby, errors caused by the NW can be avoided, and improvement in communication reliability can be achieved.

[0257] In addition, in the case where the reception processing of at least one multicast PDSCH is successful, the UE can also send ACK for the subsequent multicast PDSCH a specific number of times regardless of the reception processing result of the subsequent multicast PDSCH. The number of times of sending ACK can also be the total value N of the number of times of sending ACK for the multicast PDSCH whose initial reception processing is successful and the number of times of sending ACK for the subsequent multicast PDSCH.

[0258] This value N can either be predefined in the specification, or be notified (set) to the UE through higher layer signaling, or be a value reported to the NW through the UE capability information (UE Capability) of the UE.

[0259] In addition, a specific RV value can also be applied to the multicast PDSCH. In addition, a specific RV value can also be applied to at least the initially received multicast PDSCH. The specific RV value can also be a self-decodable RV. The self-decodable RV can also be a specific RV (for example, RV = 0, 3). The UE receives the multicast PDSCH to which the self-decodable RV is applied, thereby being able to increase the probability of decoding based on the PUSCH to which the RV is applied. For example, the specific RV value can either be 0, or be 0 and 3.

[0260] Figure 13 It is a diagram showing an example of HARQ-ACK transmission for retransmission of a multicast PDSCH. Figure 13The structure of the scheduling DCI and each multicast PDSCH shown is the same as Figure 9 that. The UE uses the PUCCH resources corresponding to each multicast PDSCH to send HARQ-ACK (ACK / NACK) for the repeated transmission of the multicast PDSCH. For multicast PDSCH1-4, PUCCH1-4 are the corresponding resources for HARQ-ACK transmission respectively.

[0261] In Figure 13 the example shown, the reception process of the multicast PDSCH1 of a certain UE fails. This UE does not send (or can send) the HARQ-ACK (NACK) corresponding to the multicast PDSCH1. Then, the reception process of the multicast PDSCH1 of this UE is successful. This UE uses PUCCH2 to send the HARQ-ACK (ACK) corresponding to the multicast PDSCH2.

[0262] Furthermore, this UE sends (or can not send) the ACK corresponding to each of the multicast PDSCH3 and 4 regardless of the reception process results of the multicast PDSCH3 and 4 received after the multicast PDSCH2.

[0263] In addition, Figure 13 the number of repetitions, DCI, PDSCH, the number of PUCCH resources, and the allocation positions in time / frequency shown are just an example and are not limited to this example. In addition, Figure 13 the DCI1 in Figure 13 is respectively shown as DCI common to UEs, but it can also be UE-specific DCI. In addition,

[0264] Hereinafter, the spatial domain filters (UL beams, UL spatial relations) applied in the transmission of HARQ-ACK corresponding to the multicast PDSCH will be described. In addition, the method for determining the spatial domain filters described below can also be applied to the HARQ-ACK of at least one of the above first - fourth embodiments.

[0265] When the UE uses one PUCCH / PUSCH resource for HARQ-ACK transmission to send HARQ-ACK for the repeated transmission of the multicast PDSCH ( Figure 12 the situation shown in the example of

[0266] The spatial domain filter can also be notified (configured, indicated) to the UE using at least one of higher layer signaling (e.g., RRC signaling), MAC signaling, and physical layer signaling (e.g., DCI). That is, the UE can also use at least one of the spatial domain filters represented by the spatial relation information (SRI) of the configured PUSCH / PUCCH or the spatial domain filter corresponding to the spatial relation of the PUSCH / PUCCH to send HARQ-ACK for the retransmission of the multicast PDSCH.

[0267] In addition, a specific spatial domain filter can also be the spatial domain filter corresponding to the default spatial relation defined in Rel.16.

[0268] In addition, a specific domain filter can also be the spatial domain filter corresponding to the spatial domain filter (DL beam) applied to multiple multicast PDSCHs. In this case, the spatial domain filter applied to the HARQ-ACK for the retransmission of the multicast PDSCH can also be the spatial domain filter applied to the initially received multicast PDSCH. In addition, the spatial domain filter applied to the HARQ-ACK for the retransmission of the multicast PDSCH can also be the spatial domain filter applied to the last received multicast PDSCH.

[0269] In addition, for example, when the UE uses the PUCCH / PUSCH resources for HARQ-ACK transmission configured for each multicast PDSCH to send HARQ-ACK for the retransmission of the multicast PDSCH ( Figure 13 the case shown in the example), the UE can also use a specific spatial domain filter (UL beam) to send each HARQ-ACK.

[0270] Hereinafter, a specific spatial domain filter will be described. However, the specific spatial domain filter applied to each HARQ-ACK can be either common to all HARQ-ACKs or determined individually for each HARQ-ACK.

[0271] The spatial domain filter can also be notified (configured, indicated) to the UE using at least one of higher layer signaling (e.g., RRC signaling), MAC signaling, and physical layer signaling (e.g., DCI). That is, the UE can also use at least one of the spatial domain filters represented by the SRI of the configured PUSCH / PUCCH or the spatial domain filter corresponding to the spatial relation of the PUSCH / PUCCH to send HARQ-ACK for the retransmission of the multicast PDSCH.

[0272] In addition, a specific spatial-domain filter may also be a spatial-domain filter corresponding to the default spatial relationship defined in Rel. 16.

[0273] In addition, a specific domain filter may also be a spatial-domain filter (DL beam) corresponding to the spatial-domain filter that is commonly applied to multiple multicast PDSCHs. In this case, the spatial-domain filter applied in the HARQ-ACK for the repeated transmission of the multicast PDSCH may also be the spatial-domain filter applied in the initially received multicast PDSCH. In addition, the spatial-domain filter applied in the HARQ-ACK for the repeated transmission of the multicast PDSCH may also be the spatial-domain filter applied in the last received multicast PDSCH.

[0274] In addition, a specific domain filter may also be a spatial-domain filter (DL beam) applied to each of the multicast PDSCHs corresponding to each HARQ-ACK.

[0275] In addition, a specific domain filter may also be a spatial-domain filter (DL beam) corresponding to the spatial-domain filter of the multicast PDSCH for which the reception process was finally successful. In this case, the UE may also apply the spatial-domain filter corresponding to the spatial-domain filter of the multicast PDSCH for which the reception process was successful to the transmission of the HARQ-ACK for the subsequent multicast PDSCH.

[0276] As described above, according to the fifth embodiment, low latency and low overhead of the PDCCH can be achieved, and reliable reception of the multicast PDSCH can be performed.

[0277] <Sixth Embodiment>

[0278] At least one parameter included in the higher-layer (RRC) parameters (at least one of PDSCH configuration (PDSCH-Config), PUCCH configuration (PUCCH-Config), and PUSCH configuration (PUSCH-Config)), the unicast parameters, and the multicast parameters may also be notified to the UE separately. For example, the UE may receive the unicast parameters and the multicast parameters separately for the TDRA and FDRA included in the PDSCH configuration.

[0279] In addition, this embodiment may also be applied to at least one of the first to fifth embodiments described above.

[0280] In addition, the higher-layer parameters in the present disclosure may also be replaced with a higher-layer parameter list, a higher-layer parameter set, a higher-layer parameter table, etc.

[0281] In addition, the UE may assume that the DCI reference detected in the resources for multicast (e.g., CORESET, search space, monitoring opportunity) is set as a high-layer parameter for multicast, or the UE may assume that the DCI reference other than this is set as a high-layer parameter for unicast.

[0282] In addition, the UE may assume that the DCI reference to which the DCI format for multicast is applied is set as a high-layer parameter for multicast, or the UE may assume that the DCI reference other than this is set as a high-layer parameter for unicast.

[0283] In addition, the UE may assume that the DCI reference scrambled by CRC with the RNTI for multicast is set as a high-layer parameter for multicast, or the UE may assume that the DCI reference other than this is set as a high-layer parameter for unicast.

[0284] Figure 14 FIG. is an example showing high-layer parameter references for unicast DCI and multicast DCI. In Figure 14 the UE assumes that the DCI reference for unicast is set as a high-layer parameter list for unicast, and assumes that the DCI reference for multicast is set as a high-layer parameter list for multicast.

[0285] (Wireless communication system)

[0286] Hereinafter, the structure of a wireless communication system according to an embodiment of the present disclosure will be described. In this wireless communication system, communication is performed using any one of or a combination of the wireless communication methods according to the above-described embodiments of the present disclosure.

[0287] Figure 15 FIG. is an example showing a schematic structure of a wireless communication system according to an embodiment. The wireless communication system 1 may also be a system that realizes communication using Long Term Evolution (LTE) standardized by the Third Generation Partnership Project (3GPP), New Radio (5G NR) of the fifth-generation mobile communication system, or the like.

[0288] In addition, the wireless communication system 1 may also support dual connectivity (Multi-RAT Dual Connectivity (MR-DC)) between multiple Radio Access Technologies (RATs). MR-DC may also include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), and so on.

[0289] In EN-DC, the base station (eNB) of LTE (E-UTRA) is the Master Node (MN), and the base station (gNB) of NR is the Secondary Node (SN). In NE-DC, the base station (gNB) of NR is the MN, and the base station (eNB) of LTE (E-UTRA) is the SN.

[0290] The wireless communication system 1 may also support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity where both the MN and the SN are base stations (gNBs) of NR (NR-NR Dual Connectivity (NN-DC))).

[0291] The wireless communication system 1 may also include a base station 11 that forms a macro cell C1 with a relatively wide coverage area, and a base station 12 (12a - 12c) that is configured within the macro cell C1 and forms a small cell C2 that is narrower than the macro cell C1. The user terminal 20 may also be located within at least one cell. The configuration, quantity, etc. of each cell and the user terminal 20 are not limited to the manner shown in the figure. Hereinafter, without distinguishing between the base stations 11 and 12, they are collectively referred to as the base station 10.

[0292] The user terminal 20 may also be connected to at least one of the multiple base stations 10. The user terminal 20 may also utilize at least one of Carrier Aggregation (CA) and Dual Connectivity (DC) that uses multiple Component Carriers (CCs).

[0293] Each CC may also 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 also be included in FR1, and the small cell C2 may also be included in FR2. For example, FR1 may also be a frequency band below 6 GHz (sub-6 GHz), and FR2 may also be a frequency band above 24 GHz (above-24 GHz). Additionally, the frequency bands, definitions, etc. of FR1 and FR2 are not limited to these. For example, FR1 may also correspond to a frequency band higher than FR2.

[0294] In addition, the user terminal 20 may also communicate in each CC using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD).

[0295] The plurality of base stations 10 may also be connected by wire (e.g., optical fiber based on the Common Public Radio Interface (CPRI), X2 interface, etc.) or wirelessly (e.g., NR communication). For example, when NR communication is used as a backhaul between the base stations 11 and 12, the base station 11, which is the upper station, may also be referred to as an Integrated Access Backhaul (IAB) donor, and the base station 12, which is a relay station (relay), may also be referred to as an IAB node.

[0296] The base station 10 may also be connected to the core network 30 via other base stations 10 or directly. The core network 30 may, for example, also include at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), etc.

[0297] The user terminal 20 may also be a terminal that supports at least one of communication methods such as LTE, LTE-A, 5G, etc.

[0298] In the wireless communication system 1, a wireless access method based on Orthogonal Frequency Division Multiplexing (OFDM) can also be used. For example, in at least one of the Downlink (DL) and the Uplink (UL), 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), etc. can also be used.

[0299] The wireless access method can also be referred to as a waveform. Additionally, in the wireless communication system 1, in the wireless access methods of the UL and the DL, other wireless access methods (e.g., other single-carrier transmission methods, other multi-carrier transmission methods) can also be used.

[0300] As a downlink channel, in the wireless communication system 1, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)), a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc., which are shared among the user terminals 20, can also be used.

[0301] Furthermore, as an uplink channel, in the wireless communication system 1, an uplink shared channel (Physical Uplink Shared Channel (PUSCH)), an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), etc., which are shared among the user terminals 20, can also be used.

[0302] User data, high-layer control information, System Information Block (SIB), etc. are transmitted through the PDSCH. User data, high-layer control information, etc. can also be transmitted through the PUSCH. In addition, the Master Information Block (MIB) can also be transmitted through the PBCH.

[0303] Low-layer control information can also be transmitted through the PDCCH. The low-layer control information can also include, for example, downlink control information (Downlink Control Information (DCI)), and the downlink control information includes scheduling information for at least one of the PDSCH and the PUSCH.

[0304] In addition, the DCI that schedules the PDSCH can also be referred to as DL allocation, DL DCI, etc., and the DCI that schedules the PUSCH can also be referred to as UL grant, UL DCI, etc. In addition, the PDSCH can also be replaced by DL data, and the PUSCH can also be replaced by UL data.

[0305] In the detection of the PDCCH, the Control Resource Set (CORESET) and the search space can also be utilized. The CORESET corresponds to the resource for searching for DCI. The search space corresponds to the search area and search method for PDCCH candidates. One CORESET can also be associated with one or more search spaces. The UE can also monitor the CORESET associated with a certain search space based on the search space setting.

[0306] One search space can also correspond to PDCCH candidates equivalent to one or more aggregation levels. One or more search spaces can also be referred to as a search space set. In addition, the "search space", "search space set", "search space setting", "search space set setting", "CORESET", "CORESET setting", etc. in the present disclosure can also be replaced with each other.

[0307] Uplink control information (Uplink Control Information (UCI)) including at least one of channel state information (Channel State Information (CSI)), delivery confirmation information (which can also be referred to as Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (Scheduling Request (SR)) can also be transmitted through PUCCH. The random access preamble for establishing a connection with the cell can also be transmitted through PRACH.

[0308] In addition, in the present disclosure, the downlink, uplink, etc. can also be expressed without "link". Furthermore, it can also be expressed without "Physical" at the beginning of various channels.

[0309] In the wireless communication system 1, synchronization signal (Synchronization Signal (SS)), downlink reference signal (Downlink Reference Signal (DL-RS)), etc. can also be transmitted. As the DL-RS, in the wireless communication system 1, cell-specific reference signal (Cell-specific Reference Signal (CRS)), channel state information reference signal (Channel State Information Reference Signal (CSI-RS)), demodulation reference signal (DeModulation Reference Signal (DMRS)), positioning reference signal (Positioning Reference Signal (PRS)), phase tracking reference signal (Phase Tracking Reference Signal (PTRS)), etc. can also be transmitted.

[0310] The synchronization signal can, for example, also be at least one of the primary synchronization signal (Primary Synchronization Signal (PSS)) and the secondary synchronization signal (Secondary Synchronization Signal (SSS)). The signal block including SS (PSS, SSS) and PBCH (and DMRS for PBCH) can also be referred to as an SS / PBCH block, an SS block (SS Block (SSB)), etc. In addition, SS, SSB, etc. can also be referred to as reference signals.

[0311] In addition, in the wireless communication system 1, as the uplink reference signal (UL-RS), it is also possible to transmit a measurement reference signal (sounding reference signal (SRS)), a demodulation reference signal (DMRS), etc. In addition, the DMRS can also be referred to as a user terminal specific reference signal (UE-specific Reference Signal).

[0312] (Base station)

[0313] Figure 16 FIG. is an example showing the structure of a base station according to an embodiment. The base station 10 includes a control unit 110, a transmission / reception unit 120, a transmission / reception antenna 130, and a transmission path interface (transmission line interface) 140. In addition, one or more of the control unit 110, the transmission / reception unit 120, the transmission / reception antenna 130, and the transmission path interface 140 may be provided respectively.

[0314] In addition, in this example, the functional blocks of the characteristic parts in this embodiment are mainly shown, and it can also be assumed that the base station 10 also has other functional blocks required for wireless communication. A part of the processing of each unit described below may also be omitted.

[0315] The control unit 110 implements overall control of the base station 10. The control unit 110 can be composed of a controller, a control circuit, etc. described based on the common knowledge in the technical field related to the present disclosure.

[0316] The control unit 110 can also control the generation, scheduling (e.g., resource allocation, mapping), etc. of signals. The control unit 110 can also control the transmission / reception, measurement, etc. using the transmission / reception unit 120, the transmission / reception antenna 130, and the transmission path interface 140. The control unit 110 can also generate data, control information, a sequence, etc. to be transmitted as signals, and forward them to the transmission / reception unit 120. The control unit 110 can also perform call processing (setting, releasing, etc.) of communication channels, state management of the base station 10, management of radio resources, etc.

[0317] The transmission and reception unit 120 may also include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may also include a transmission processing unit 1211 and a reception processing unit 1212. The transmission and reception unit 120 can be composed of a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter (phase shifter), a measurement circuit, a transmission and reception circuit, etc., which are described based on the common knowledge in the technical field related to the present disclosure.

[0318] The transmission and reception unit 120 may be configured as an integrated transmission and reception unit, or may be composed of a transmission unit and a reception unit. The transmission unit may also be composed of a transmission processing unit 1211 and an RF unit 122. The reception unit may also be composed of a reception processing unit 1212, an RF unit 122, and a measurement unit 123.

[0319] The transmission and reception antenna 130 can be composed of an antenna described based on the common knowledge in the technical field related to the present disclosure, such as an array antenna.

[0320] The transmission and reception unit 120 may also transmit the above-mentioned downlink channels, synchronization signals, downlink reference signals, etc. The transmission and reception unit 120 may also receive the above-mentioned uplink channels, uplink reference signals, etc.

[0321] The transmission and reception unit 120 may also use digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc. to form at least one of a transmission beam and a reception beam.

[0322] For example, the transmission and reception unit 120 (transmission processing unit 1211) may also perform processing at the Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on the data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

[0323] The transmission / reception unit 120 (transmission processing unit 1211) can also perform transmission processing such as channel coding (which may also include error correction coding), modulation, mapping, filter processing (filtering), Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, digital-to-analog conversion, etc. on the bit string to be transmitted, and output a baseband signal.

[0324] The transmission / reception unit 120 (RF unit 122) can also perform modulation to the radio frequency band, filter processing, amplification, etc. on the baseband signal, and transmit the radio frequency band signal via the transmission / reception antenna 130.

[0325] On the other hand, the transmission / reception unit 120 (RF unit 122) can also perform amplification, filter processing, demodulation to the baseband signal, etc. on the radio frequency band signal received through the transmission / reception antenna 130.

[0326] The transmission / reception unit 120 (reception processing unit 1212) can also perform reception processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filter processing, demapping, demodulation, decoding (which may also include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing, etc. on the obtained baseband signal, and obtain user data, etc.

[0327] The transmission / reception unit 120 (measurement unit 123) may also perform measurements related to the received signal. For example, the measurement unit 123 may also perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may also perform measurements on received power (e.g., Reference Signal Received Power (RSRP)), reception quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may also be output to the control unit 110.

[0328] The transmission path interface 140 may also transmit and receive signals (backhaul signaling) between the device included in the core network 30, other base stations 10, etc., and may also obtain, transmit, etc. user data (user plane data), control plane data, etc. for the user terminal 20.

[0329] In addition, the transmission unit and the reception unit of the base station 10 in the present disclosure may also be constituted by at least one of the transmission / reception unit 120, the transmission / reception antenna 130, and the transmission path interface 140.

[0330] The transmission / reception unit 120 may also transmit the initial transmission of the downlink (DL) data that is multicast. The control unit 110 may also control the retransmission of the DL data that is multicast based on the decoding result of the DL data (second embodiment).

[0331] The transmission / reception unit 120 may also transmit the initial transmission of the downlink (DL) data that is scheduled and multicast based on the first downlink control information (DCI). The control unit 110 may also control the retransmission of the DL data that is scheduled and unicast based on the second DCI based on the decoding result of the initial transmission (third embodiment).

[0332] The transmission / reception unit 120 may also transmit downlink (DL) data that is scheduled by a downlink control information (DCI) and multicast in multiple opportunities. The control unit 110 may also control the reception of Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) information for the DL data based on the DCI (the fifth embodiment).

[0333] (User Equipment)

[0334] Figure 17 FIG. is an example showing the structure of a user equipment according to an embodiment. The user equipment 20 includes a control unit 210, a transmission / reception unit 220, and a transmission / reception antenna 230. In addition, one or more of the control unit 210, the transmission / reception unit 220, and the transmission / reception antenna 230 may be provided respectively.

[0335] In addition, in this example, the functional blocks of the characteristic parts in this embodiment are mainly shown, and it can be assumed that the user equipment 20 also has other functional blocks required for wireless communication. A part of the processing of each unit described below may also be omitted.

[0336] The control unit 210 implements the overall control of the user equipment 20. The control unit 210 can be composed of a controller, a control circuit, etc. described based on the common knowledge in the technical field related to the present disclosure.

[0337] The control unit 210 may also control the generation, mapping, etc. of signals. The control unit 210 may also control the transmission / reception, measurement, etc. using the transmission / reception unit 220 and the transmission / reception antenna 230. The control unit 210 may also generate data, control information, sequences, etc. to be transmitted as signals, and forward them to the transmission / reception unit 220.

[0338] The transmission / reception unit 220 may also include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may also include a transmission processing unit 2211 and a reception processing unit 2212. The transmission / reception unit 220 can be composed of a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transmission / reception circuit, etc. described based on the common knowledge in the technical field related to the present disclosure.

[0339] The transmission / reception unit 220 may be configured as an integrated transmission / reception unit, or may be composed of a transmission unit and a reception unit. The transmission unit may be composed of the transmission processing unit 2211 and the RF unit 222. The reception unit may be composed of the reception processing unit 2212, the RF unit 222, and the measurement unit 223.

[0340] The transmitting and receiving antenna 230 can be constituted by an antenna that can be described based on common knowledge in the technical field related to the present disclosure, such as an array antenna.

[0341] The transmitting and receiving unit 220 can also receive the above-mentioned downlink channels, synchronization signals, downlink reference signals, etc. The transmitting and receiving unit 220 can also transmit the above-mentioned uplink channels, uplink reference signals, etc.

[0342] The transmitting and receiving unit 220 can also use digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc. to form at least one of a transmitting beam and a receiving beam.

[0343] The transmitting and receiving unit 220 (transmission processing unit 2211) can also, for example, perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on the data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

[0344] The transmitting and receiving unit 220 (transmission processing unit 2211) can also perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filter processing, DFT processing (if necessary), IFFT processing, precoding, digital-to-analog conversion, etc. on the bit string to be transmitted, and output a baseband signal.

[0345] In addition, regarding whether to apply DFT processing, it can also be based on the setting of transform precoding. For a certain channel (e.g., PUSCH), when transform precoding is effective (enabled), the transmitting and receiving unit 220 (transmission processing unit 2211) can also perform DFT processing as the above-mentioned transmission processing in order to transmit the channel using the DFT-s-OFDM waveform. In other cases, the transmitting and receiving unit 220 (transmission processing unit 2211) can also not perform DFT processing as the above-mentioned transmission processing.

[0346] The transmitting and receiving unit 220 (RF unit 222) can also perform modulation to the radio frequency band, filter processing, amplification, etc. on the baseband signal, and transmit the radio frequency band signal via the transmitting and receiving antenna 230.

[0347] On the other hand, the transmitting and receiving unit 220 (RF unit 222) can also perform amplification, filter processing, demodulation to the baseband signal, etc. on the radio frequency band signal received through the transmitting and receiving antenna 230.

[0348] The transmission / reception unit 220 (reception processing unit 2212) can also perform reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filter processing, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing on the acquired baseband signal, and acquire user data and the like.

[0349] The transmission / reception unit 220 (measurement unit 223) can also perform measurements related to the received signal. For example, the measurement unit 223 can also perform RRM measurements, CSI measurements, etc. based on the received signal. The measurement unit 223 can also measure the received power (e.g., RSRP), reception quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results can also be output to the control unit 210.

[0350] In addition, the transmission unit and the reception unit of the user terminal 20 in the present disclosure can also be constituted by at least one of the transmission / reception unit 220 and the transmission / reception antenna 230.

[0351] The transmission / reception unit 220 can also perform the initial transmission of the downlink (DL) data that is multicast. The control unit 210 can also receive the retransmission of the multicast DL data based on the decoding result of the DL data (second embodiment).

[0352] When the decoding of the DL data is successful, the control unit 210 can also perform control so as not to transmit the hybrid automatic repeat request acknowledgement (HARQ-ACK) information for the initial transmission (second embodiment).

[0353] When the decoding of the DL data is successful, the control unit 210 can also perform control so as to transmit the hybrid automatic repeat request acknowledgement (HARQ-ACK) information indicating a positive response to the initial transmission (second embodiment).

[0354] The transmission / reception unit 220 can also receive downlink control information, which includes information related to the resources of the physical downlink shared channel (PDSCH) carrying the initial transmission and information related to the resources of the PDSCH carrying the retransmission (second embodiment).

[0355] The transmission / reception unit 220 may also receive an initial transmission of downlink (DL) data that is scheduled based on first downlink control information (DCI) and is multicast. The control unit 210 may also control reception of a retransmission of the DL data that is scheduled based on second DCI and is unicast, based on a decoding result of the initial transmission (third embodiment).

[0356] The transmission / reception unit 220 may also receive the second DCI after a specific time from a reception timing of the initial transmission (fourth embodiment).

[0357] The control unit 210 may also control blind detection of the second DCI based on a reception timing of the second DCI (fourth embodiment).

[0358] The transmission / reception unit 220 may also receive downlink (DL) data that is scheduled by one downlink control information (DCI) and is multicast in a plurality of opportunities. The control unit 210 may also control transmission of hybrid automatic repeat request acknowledgement (HARQ-ACK) information for the DL data based on the DCI (fifth embodiment).

[0359] The control unit 210 may also perform control so as not to transmit the HARQ-ACK information (fifth embodiment).

[0360] In a case where reception processing of the DL data in at least one of the plurality of opportunities is successful, the control unit 210 may also transmit HARQ-ACK information indicating an affirmative response to the DL data (fifth embodiment).

[0361] In a case where reception processing of the DL data in at least one of the plurality of opportunities is successful, the control unit 210 may also perform control so as to use HARQ-ACK resources corresponding to a first opportunity among the at least one opportunity to transmit HARQ-ACK information for the DL data (fifth embodiment).

[0362] (Hardware configuration)

[0363] In addition, the block diagrams used in the description of the above embodiments illustrate blocks of functional units. These functional blocks (structural units) are implemented by any combination of at least one of hardware and software. Furthermore, there is no particular limitation on the implementation method of each functional block. That is, each functional block can be implemented by a single device physically or logically combined, or can be implemented by two or more physically or logically separated devices directly or indirectly (e.g., by wire, wireless, etc.) connected by these multiple devices. A functional block can also be implemented by combining the above single device or the above multiple devices with software.

[0364] Here, in terms of functions, there are judgment, decision, determination, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, solution, selection, establishment, comparison, assumption, expectation, regarded as, broadcasting, notifying, communicating, forwarding, configuration (setting), reconfiguration (resetting), allocation (mapping), assignment, etc., but are not limited to these. For example, a functional block (structural unit) that implements a transmission function may also be referred to as a transmitting unit, a transmitter, etc. Any one of them is as described above, and the implementation method is not particularly limited.

[0365] For example, a base station, a user terminal, etc. in an embodiment of the present disclosure can also function as a computer that processes the wireless communication method of the present disclosure. Figure 18 FIG. is an example of the hardware structure of a base station and a user terminal according to an embodiment. The above base station 10 and user terminal 20 can also 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.

[0366] In addition, in the present disclosure, terms such as device, circuit, equipment, section, unit, etc. can be mutually replaced. The hardware structure of the base station 10 and the user terminal 20 can be configured to include one or more of each device shown in the figure, or can be configured not to include some devices.

[0367] For example, only one processor 1001 is illustrated, but there may be multiple processors. In addition, the processing may be executed by one processor, or may be executed by two or more processors simultaneously, sequentially, or by other means. Further, the processor 1001 may also be implemented by one or more chips.

[0368] Regarding each function in the base station 10 and the user terminal 20, for example, by reading a specific software (program) into hardware such as the processor 1001 and the memory 1002, the processor 1001 performs operations and controls communication via the communication device 1004, or controls at least one of reading and writing data in the memory 1002 and the storage 1003, thereby implementing the function.

[0369] The processor 1001 operates the operating system, for example, to control the entire computer. The processor 1001 may also be constituted by a central processing unit (Central Processing Unit (CPU)) including an interface with peripheral devices, a control device, an arithmetic device, registers, etc. For example, at least a part of the above control unit 110 (210), transmission / reception unit 120 (220), etc. may also be implemented by the processor 1001.

[0370] In addition, the processor 1001 reads a program (program code), software module, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and performs various processes based on them. As the program, a program that causes a computer to execute at least a part of the operations described in the above embodiments may be used. For example, the control unit 110 (210) may also be implemented by a control program stored in the memory 1002 and operating in the processor 1001, and the same applies to other functional blocks.

[0371] The memory 1002 may also be a computer-readable recording medium, for example, constituted by at least one of a read-only memory (Read Only Memory (ROM)), an erasable programmable read-only memory (Erasable Programmable ROM (EPROM)), an electrically erasable programmable read-only memory (Electrically EPROM (EEPROM)), a random access memory (Random Access Memory (RAM)), and other appropriate storage media. The memory 1002 may also be referred to as a register, a cache, a main memory (main storage device), etc. The memory 1002 can store a program (program code), software module, etc. executable for implementing the wireless communication method according to an embodiment of the present disclosure.

[0372] The storage 1003 can also be a computer-readable recording medium, which is composed of at least one of, for example, a flexible disc, a floppy (registered trademark) disc, an optical disc (such as a compact disc (Compact Disc ROM (CD-ROM)), a digital versatile disc, a Blu-ray (registered trademark) disc), a removable disc, a hard disk drive, a smart card, a flash memory device (such as a card, a stick, a key drive), a magnetic stripe, a database, a server, and other appropriate storage media. The storage 1003 can also be referred to as an auxiliary storage device.

[0373] The communication device 1004 is hardware (a transmitting and receiving device) for performing inter-computer communication 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, a communication module, etc. In order to implement at least one of, for example, Frequency Division Duplex (FDD) and Time Division Duplex (TDD), the communication device 1004 can also be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. For example, the above-mentioned transmitting and receiving unit 120(220), transmitting and receiving antenna 130(230), etc. can also be implemented by the communication device 1004. The transmitting and receiving unit 120(220) can also be physically or logically separated and implemented by a transmitting unit 120a(220a) and a receiving unit 120b(220b).

[0374] The input device 1005 is an input device (such as a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) for receiving an external input. The output device 1006 is an output device (such as a display, a speaker, a Light Emitting Diode (LED) lamp, etc.) for performing an output to the outside. In addition, the input device 1005 and the output device 1006 can also be of an integrated structure (such as a touch panel).

[0375] In addition, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 can be constituted by a single bus or by different buses between each device.

[0376] In addition, the base station 10 and the user terminal 20 may also be configured to include hardware such as a microprocessor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Programmable Logic Device (PLD), and a Field Programmable Gate Array (FPGA). Some or all of the functional blocks may also be implemented using this hardware. For example, the processor 1001 may also be implemented using at least one of these hardware components.

[0377] (Variant example)

[0378] Furthermore, with regard to the terms described in this disclosure and the terms required for understanding this disclosure, they may also be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may also be replaced with each other. In addition, a signal may also be a message. A Reference Signal can also be abbreviated as RS and may also be referred to as a Pilot, a pilot signal, etc. according to the applied standard. In addition, a Component Carrier (CC) may also be referred to as a cell, a frequency carrier, a carrier frequency, etc.

[0379] A radio frame may also be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting the radio frame may also be referred to as a subframe. Further, a subframe may also be composed of one or more time slots in the time domain. A subframe may also have a fixed time length (e.g., 1 ms) independent of the numerology.

[0380] Here, the numerology may also refer to communication parameters applied in at least one of the transmission and reception of a certain signal or channel. For example, the numerology may also represent at least one of 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, specific filtering processing performed by a transmitter-receiver in the frequency domain, and specific windowing processing performed by a transmitter-receiver in the time domain.

[0381] A time slot can also be composed of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.). In addition, a time slot can also be a time unit based on a parameter set.

[0382] A time slot can also contain multiple mini-slots. Each mini-slot can also be composed of one or more symbols in the time domain. In addition, a mini-slot can also be referred to as a sub-slot. A mini-slot can also be composed of a smaller number of symbols than a time slot. The PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot can also be referred to as PDSCH (PUSCH) mapping type A. The PDSCH (or PUSCH) transmitted using a mini-slot can also be referred to as PDSCH (PUSCH) mapping type B.

[0383] A radio frame, a sub-frame, a time slot, a mini-slot, and a symbol all represent time units when transmitting signals. A radio frame, a sub-frame, a time slot, a mini-slot, and a symbol can also use their respective other names. In addition, the time units such as frames, sub-frames, time slots, mini-slots, and symbols in this disclosure can also be replaced with each other.

[0384] For example, a sub-frame can also be referred to as a TTI, multiple consecutive sub-frames can also be referred to as a TTI, and a time slot or a mini-slot can also be referred to as a TTI. That is, at least one of a sub-frame and a TTI can be a sub-frame (1 ms) in the existing LTE, can also be a period shorter than 1 ms (for example, 1 - 13 symbols), or can also be a period longer than 1 ms. In addition, the unit representing a TTI can also not be referred to as a sub-frame, but as a time slot, a mini-slot, etc.

[0385] Here, a TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as the frequency bandwidth and transmission power that can be used in each user terminal) to each user terminal in units of TTI. In addition, the definition of a TTI is not limited to this.

[0386] A TTI can also be the transmission time unit of a data packet (transmission block), a code block, a codeword, etc. that has undergone channel coding, and can also become the processing unit for scheduling, link adaptation, etc. In addition, when a TTI is given, the time interval (such as the number of symbols) actually mapped with a transmission block, a code block, a codeword, etc. can also be shorter than this TTI.

[0387] In addition, when a time slot or a mini-slot is referred to as a TTI, more than one TTI (i.e., more than one time slot or more than one mini-slot) can also be the minimum time unit for scheduling. In addition, the number of time slots (mini-slots) that constitute the minimum time unit of this scheduling can also be controlled.

[0388] A TTI with a time length of 1 ms can also be referred to as a normal TTI (TTI in 3GPP Rel.8-12), a standard TTI, a long TTI, a normal subframe, a standard subframe, a long subframe, a time slot, etc. A TTI shorter than the normal TTI can also be referred to as a shortened TTI, a short TTI, a partial TTI, a shortened subframe, a short subframe, a mini-slot, a sub-slot, a time slot, etc.

[0389] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) can also be replaced with a TTI having a time length exceeding 1 ms, and a short TTI (e.g., a shortened TTI, etc.) can also be replaced with a TTI having a TTI length less than that of the long TTI and not less than 1 ms.

[0390] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and can also include one or more consecutive subcarriers (subcarriers) in the frequency domain. The number of subcarriers included in the RB can be the same regardless of the parameter set, for example, it can be 12. The number of subcarriers included in the RB can also be determined based on the parameter set.

[0391] In addition, an RB can also include one or more symbols in the time domain, and can also be the length of a time slot, a mini-slot, a subframe, or a TTI. A TTI, a subframe, etc. can also be composed of one or more resource blocks respectively.

[0392] In addition, one or more RBs can also be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0393] In addition, a resource block can also be composed of one or more resource elements (REs). For example, one RE can also be a radio resource area of a subcarrier and a symbol.

[0394] A Bandwidth Part (BWP) (which may also be referred to as partial bandwidth, etc.) may also represent a subset of consecutive common RBs (common resource blocks) used for a certain parameter set in a certain carrier. Here, the common RBs may also be determined by the indices of the RBs based on the common reference point of the carrier. The PRBs may also be defined in a certain BWP and be numbered additionally within that BWP.

[0395] A BWP may also include a UL BWP (BWP for UL) and a DL BWP (BWP for DL). For a UE, one or more BWPs may be set within a carrier.

[0396] At least one of the set BWPs may be active, and the UE may not assume to transmit and receive specific signals / channels outside the active BWP. Additionally, in the present disclosure, “cell”, “carrier”, etc. may also be replaced with “BWP”.

[0397] In addition, the structures such as the above-mentioned radio frames, subframes, time slots, mini-slots, and symbols are merely examples. For example, the number of subframes included in a radio frame, the number of time slots in each subframe or radio frame, the number of mini-slots included in a time slot, the symbols and the number of RBs included in a time slot or mini-slot, the number of subcarriers included in an RB, and the number of symbols, symbol length, Cyclic Prefix (CP) length, etc. within a TTI can be changed in various ways.

[0398] Furthermore, the information, parameters, etc. described in the present disclosure may be represented by absolute values, may be represented by relative values with respect to a specific value, or may also be represented by corresponding other information. For example, radio resources may also be indicated by specific indices.

[0399] In the present disclosure, the names used for parameters, etc. are not restrictive names in all aspects. Furthermore, the mathematical formulas, etc. using these parameters may also be different from those clearly disclosed in the present disclosure. Various channels (PUCCH, PDCCH, etc.) and information elements can be identified by any suitable names, and thus, the various names assigned to these various channels and information elements are not restrictive names in all aspects.

[0400] The information, signals, etc. described in this disclosure can also be represented using any one of a variety of different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be mentioned throughout the above description can also be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0401] In addition, information, signals, etc. can be output in at least one of the following directions: from a higher layer (upper layer) to a lower layer (lower layer), and from a lower layer to a higher layer. Information, signals, etc. can also be input and output via multiple network nodes.

[0402] The information, signals, etc. that are input and output can be stored in a specific location (e.g., a memory), or can be managed using a management table. The information, signals, etc. that are input and output can be overwritten, updated, or appended. The information, signals, etc. that are output can also be deleted. The information, signals, etc. that are input can also be sent to other devices.

[0403] The notification of information is not limited to the methods / embodiments described in this disclosure, and can also be performed using other methods. For example, the notification of information in this disclosure can also be implemented by physical layer signaling (e.g., downlink control information (Downlink Control Information (DCI)), uplink control information (Uplink Control Information (UCI))), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB), etc.), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0404] In addition, physical layer signaling may also be referred to as Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), L1 control information (L1 control signal), etc. In addition, RRC signaling may also be referred to as an RRC message. For example, it may also be an RRC Connection Setup message, an RRC Connection Reconfiguration (RRC Connection Re - setup) message, etc. In addition, MAC signaling may also be notified, for example, using a MAC Control Element (MAC CE).

[0405] In addition, the notification of specific information (e.g., the notification of "is X") is not limited to explicit notification and may also be performed implicitly (e.g., by not performing the notification of the specific information or by the notification of other information).

[0406] The determination can be made by a value represented by one bit (0 or 1), by a true - false value (Boolean value) represented by true or false, or by a numerical comparison (e.g., comparison with a specific value).

[0407] Software, whether referred to as software, firmware, middleware, micro - code, hardware description language, or by any other name, should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, sub - programs, software modules, applications, software applications, software packages, routines, sub - routines, objects, executable files, execution threads, processes, functions, etc.

[0408] In addition, software, instructions, information, etc. can also be sent and received via a transmission medium. For example, when software is sent from a website, server, or other remote source using at least one of wired technologies (coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), etc.) and wireless technologies (infrared, microwave, etc.), at least one of these wired and wireless technologies is included in the definition of the transmission medium.

[0409] Terms such as "system" and "network" used in this disclosure can be used interchangeably. A "network" can also mean a device (e.g., a base station) included in the network.

[0410] In this disclosure, terms such as "precoding", "precoder", "weight (precoding weight)", "Quasi-Co-Location (QCL)", "Transmission Configuration Indication state (TCI state)", "spatial relation", "spatial domain filter", "transmission 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. can be used interchangeably.

[0411] 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. can be used interchangeably. There are also cases where base stations are referred to using terms such as macro cell, small cell, femto cell, pico cell, etc.

[0412] The base station can accommodate one or more (e.g., three) cells. In the case where the base station accommodates multiple cells, the overall coverage area of the base station can be divided into multiple smaller areas, and each of the smaller areas can also provide communication services through 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 whole of the coverage area of at least one of the base station and the base station subsystem that provides communication services within the coverage range.

[0413] In the present disclosure, terms such as "Mobile Station (MS)", "user terminal", "user device (User Equipment (UE))", "terminal", etc. can be used interchangeably.

[0414] There are also cases where the mobile station is referred to by subscriber station, mobile unit, subscriber unit, radio unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, hand set, user agent, mobile client, client, or several other appropriate terms.

[0415] At least one of the base station and the mobile station can also be referred to as a transmitting device, a receiving device, a wireless communication device, etc. Additionally, at least one of the base station and the mobile station can be a device mounted on a moving body, the moving body itself, etc. The moving body can be a vehicle (e.g., a car, an airplane, etc.), a moving body that moves in an unmanned manner (e.g., a drone, an autonomous vehicle, etc.), or a robot (humanoid or non-humanoid). Additionally, at least one of the base station and the mobile station also includes a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station can also be an Internet of Things (IoT) device such as a sensor.

[0416] In addition, the base station in the present disclosure can also be replaced by a user terminal. For example, for a structure in which communication between a base station and a user terminal is replaced by communication between multiple user terminals (for example, it can also be referred to as Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.), the various methods / embodiments of the present disclosure can also be applied. In this case, it can also be configured that the user terminal 20 has the functions of the above-mentioned base station 10. In addition, terms such as "uplink" and "downlink" can also be replaced by terms corresponding to inter-terminal communication (for example, "side"). For example, an uplink channel, a downlink channel, etc. can also be replaced by a side channel.

[0417] Similarly, the user terminal in the present disclosure can also be replaced by a base station. In this case, it can also be configured that the base station 10 has the functions of the above-mentioned user terminal 20.

[0418] In the present disclosure, the actions performed by the base station sometimes may also be performed by its upper node according to the situation. Obviously, in a network including one or more network nodes having base stations, various operations for communicating with terminals can be performed by the base station, one or more network nodes other than the base station (for example, considering a Mobility Management Entity (MME), a Serving-Gateway (S-GW), etc., but not limited to these), or a combination thereof.

[0419] The various methods / embodiments described in the present disclosure can be used alone, in combination, or switched during execution. In addition, the processing procedures, sequences, flowcharts, etc. of the various methods / embodiments described in the present disclosure can also be reordered as long as there is no contradiction. For example, for the methods described in the present disclosure, the elements of various steps are presented in an exemplary order, but are not limited to the specific order presented.

[0420] Each method / embodiment described in the present disclosure can also be applied 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) (x is an integer or a decimal, for example), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), systems using other appropriate wireless communication methods, next-generation systems extended based on them, etc. In addition, multiple systems can also be combined (for example, a combination of LTE or LTE-A and 5G) for application.

[0421] The description "based on" used in the present disclosure does not mean "only based on" unless otherwise specified. In other words, the description "based on" means both "only based on" and "at least based on".

[0422] Any reference to an element using terms such as "first", "second", etc. used in this disclosure does not comprehensively define the quantity or order of these elements. These terms can be used in this disclosure as a convenient method for distinguishing between more than two elements. Therefore, the reference to the first and second elements does not mean that only two elements can be adopted, or that the first element must be prior to the second element in a certain form.

[0423] The term "determining" used in this disclosure may include various actions in some cases. For example, "determining" may also be a case where judging, calculating, computing, processing, deriving, investigating, looking up (searching, inquiring) (such as searching in a table, database, or other data structure), ascertaining, etc. are regarded as performing "determining".

[0424] In addition, "determining" may also be a case where receiving (for example, receiving information), transmitting (for example, transmitting information), input, output, accessing (for example, accessing data in a memory), etc. are regarded as performing "determining".

[0425] In addition, "determining" may also be a case where resolving, selecting, choosing, establishing, comparing, etc. are regarded as performing "determining". That is, "determining" may also be a case where some actions are regarded as performing "determining".

[0426] In addition, "determining" may also be replaced by "assuming", "expecting", "considering", etc.

[0427] As used in this disclosure, the terms "connected" and "coupled", or any variations thereof, refer to all direct or indirect connections or couplings between two or more elements, and can include the situation where there is one or more intermediate elements between the two elements that are "connected" or "coupled" to each other. The coupling or connection between elements can be physical, logical, or a combination of them. For example, "connected" can also be replaced with "access".

[0428] In this disclosure, when two elements are connected, it is possible to consider using one or more wires, cables, printed electrical connections, etc., and electromagnetic energy having wavelengths in the radio frequency domain, microwave region, optical (both visible and invisible) region, etc., as several non-limiting and non-exhaustive examples, to be "connected" or "coupled" to each other.

[0429] In this disclosure, the term "A is different from B" can also mean "A and B are different from each other". Additionally, this term can also mean "A and B are each different from C". Terms such as "separated" and "coupled" can be interpreted in the same way as "different".

[0430] When the terms "include", "including", and their variations are used in this disclosure, these terms, like the term "comprising", are meant in an inclusive sense. Further, the term "or" used in this disclosure does not mean an exclusive or.

[0431] In this disclosure, for example, in the case where articles are added through translation such as a, an, and the in English, this disclosure can also include the case where the nouns following these articles are in the plural form.

[0432] As described above, the invention related to this disclosure has been described in detail. However, for those skilled in the art, the invention related to this disclosure is obviously not limited to the embodiments described in this disclosure. The invention related to this disclosure can be implemented in the form of modifications and changes without departing from the gist and scope of the invention determined based on the claims. Therefore, the description of this disclosure is for illustrative purposes and does not carry any restrictive meaning with respect to the invention related to this disclosure.

Claims

1. A terminal, comprising: a receiving unit that receives an initial transmission of a physical downlink shared channel (PDSCH) scheduled using a first downlink control information (DCI); and a control unit that controls reception of the second DCI based on a decoding result of the initial transmission of the PDSCH and a timing at which the second DCI for scheduling a retransmission of the PDSCH is detected, wherein the control unit receives the second DCI when decoding of the initial transmission of the PDSCH fails and the timing at which the second DCI is detected is later than a specific timing, wherein the control unit receives a retransmission of the PDSCH when receiving the second DCI, wherein the initial transmission of the PDSCH and the retransmission of the PDSCH are multicast.

2. The terminal according to claim 1, wherein when the PDSCH is successfully decoded, the control unit controls not to send a hybrid automatic repeat request acknowledgement (HARQ-ACK) message indicating a positive acknowledgement for the initial transmission of the PDSCH.

3. The terminal according to claim 1, wherein when the PDSCH is successfully decoded, the control unit controls to send a hybrid automatic repeat request acknowledgement (HARQ-ACK) message indicating a positive acknowledgement for the initial transmission of the PDSCH.

4. The terminal according to claim 1, wherein a radio network temporary identifier (RNTI) of the second DCI is common with an RNTI of the first DCI.

5. A wireless communication method for a terminal, comprising: receiving an initial transmission of a physical downlink shared channel (PDSCH) scheduled using a first downlink control information (DCI); controlling reception of the second DCI based on a decoding result of the initial transmission of the PDSCH and a timing at which the second DCI for scheduling a retransmission of the PDSCH is detected; receiving the second DCI when decoding of the initial transmission of the PDSCH fails and the timing at which the second DCI is detected is later than a specific timing; and receiving a retransmission of the PDSCH when receiving the second DCI, wherein the initial transmission of the PDSCH and the retransmission of the PDSCH are multicast.

6. A system including a terminal and a base station, wherein the terminal comprises: a receiving unit that receives an initial transmission of a physical downlink shared channel (PDSCH) scheduled using a first downlink control information (DCI); and a control unit that controls reception of the second DCI based on a decoding result of the initial transmission of the PDSCH and a timing at which the second DCI for scheduling a retransmission of the PDSCH is detected, wherein the control unit receives the second DCI when decoding of the initial transmission of the PDSCH fails and the timing at which the second DCI is detected is later than a specific timing, wherein the control unit receives a retransmission of the PDSCH when receiving the second DCI, wherein the base station comprises: A transmitting unit that transmits an initial transmission of the PDSCH; and A control unit controls transmission of a retransmission of the PDSCH based on a decoding result of the initial transmission of the PDSCH, wherein the initial transmission of the PDSCH and the retransmission of the PDSCH are multicast.

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