User terminal and wireless communication method

Abstract

Repetition control for at least one of broadcast transmission and multicast transmission is appropriately controlled. A user terminal has a reception unit that receives specific information transmitted through at least one of broadcast and multicast, and a control unit that decides a transmission timing of repetition control information for the specific information based on at least one of a value defined in advance and information transmitted from a network.

Description

Technical Field

[0001] This disclosure relates to user terminals and wireless communication methods in next-generation mobile communication systems. Background Technology

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

[0003] The study also explored subsequent systems to LTE (e.g., also known as the 5th generation mobile communication system (5G), 5G+, New Radio (NR), 3GPP Rel.15 and later).

[0004] Existing technical documents

[0005] Non-patent literature

[0006] Non-patent document 1: 3GPP TS 36.300V8.12.0 "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] The problem that the invention aims to solve

[0008] In future wireless communication systems (e.g., NR), it is envisioned that data transmission methods will support unicast transmission dedicated to each user terminal (UE), broadcast transmission shared by multiple UEs, and multicast transmission.

[0009] Furthermore, NR has investigated cases where retransmission control (e.g., HARQ) is supported for at least one of broadcast and multicast transmissions. However, how to control retransmission for broadcast or multicast transmissions has not been adequately studied.

[0010] Therefore, one of the objectives of this disclosure is to provide a user terminal and a wireless communication method capable of properly controlling retransmission control for at least one of broadcast and multicast transmissions.

[0011] Methods for solving problems

[0012] A user terminal according to one aspect of this disclosure is characterized by comprising: a receiving unit for receiving specific information transmitted via at least one of broadcasting and multicasting; and a control unit for determining the timing of transmitting retransmission control information for the specific information based on a predefined value and at least one piece of information transmitted from the network.

[0013] Invention Effects

[0014] According to one aspect of this disclosure, retransmission control for at least one of the broadcast and multicast transmissions can be appropriately controlled. Attached Figure Description

[0015] Figure 1 This is a diagram representing an example of broadcast / multicast transmission.

[0016] Figure 2 This is a diagram illustrating an example of retransmission control involved in the first approach.

[0017] Figure 3 This is a diagram illustrating other examples of retransmission control involved in the first approach.

[0018] Figure 4 This is a diagram illustrating an example of retransmission control involved in the second approach.

[0019] Figure 5 This is a diagram illustrating an example of retransmission control involved in the third approach.

[0020] Figure 6 This is a diagram illustrating an example of retransmission control involved in the fourth method.

[0021] Figure 7 This is a diagram illustrating other examples of retransmission control involved in the fourth method.

[0022] Figure 8 This is a diagram illustrating an example of the schematic structure of a wireless communication system according to one embodiment.

[0023] Figure 9 This is a diagram illustrating an example of the structure of a base station according to one embodiment.

[0024] Figure 10 This is a diagram illustrating an example of the structure of a user terminal according to one embodiment.

[0025] Figure 11 This is a diagram illustrating an example of the hardware structure of a base station and a user terminal according to one embodiment. Detailed Implementation

[0026] In future wireless communication systems (e.g., NR), it is envisioned that unicast transmission, broadcast transmission, and multicast transmission will be supported. Unicast transmission can also transmit data or channels privately to each UE (e.g., UE-specific). At least one of broadcast transmission and multicast transmission (hereinafter also referred to as broadcast / multicast transmission) can also transmit data or channels publicly to multiple UEs (e.g., a group of UEs).

[0027] Unicast, broadcast, and multicast transmissions can also be performed using different channels (at least one of a logical channel and a physical channel). Alternatively, broadcast and multicast transmissions can also use the same structure.

[0028] Broadcast / multicast transmission becomes an effective transmission method when distributing the same content to multiple UEs (e.g., a specific group of UEs). Therefore, it is envisioned that broadcast / multicast transmission would be used, for example, in notifying users of information related to public safety, intelligent transportation systems (ITS), such as the distribution of road conditions, traffic signs, and the status of traffic lights. Alternatively, it is envisioned that broadcast / multicast transmission would be used in concerts or stadiums to notify audiences of information.

[0029] In NR, retransmission control for broadcast / multicast transmissions is also considered (e.g., HARQ operation). However, how to control retransmission for broadcast / multicast transmissions has not been sufficiently studied. There are concerns about degradation in communication quality if retransmission control is not properly implemented.

[0030] The inventors of this invention studied retransmission control for broadcast / multicast transmissions, thereby completing this invention.

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Each embodiment can be applied individually or in combination. In the following description, HARQ-based re-transmission will be used as an example for retransmission control, but it is not limited to this.

[0032] In the following description, retransmission control for broadcast transmissions can also be replaced with retransmission control for information transmitted via broadcast. Information transmitted via broadcast can also be replaced with at least one of data, data channel, DL-SCH, broadcast channel, control information, DCI, control channel, and broadcast control information. Similarly, retransmission control for multicast transmissions can also be replaced with retransmission control for information transmitted via multicast. Information transmitted via multicast can also be replaced with at least one of data, data channel, DL-SCH, multicast channel, control information, DCI, control channel, and multicast control information.

[0033] Information transmitted via broadcast / multicast can be included in data scheduled via downlink control information (e.g., DCI) (e.g., DL-SCH, shared channel, etc.), or it can be included in DCI, transmitted via higher-layer signaling (e.g., at least one of RRC signaling and broadcast information), or transmitted via dedicated signals or channels. When information transmitted via broadcast / multicast is included in data, the DCI scheduling that data can also be transmitted via broadcast / multicast. In the following description, the statement "transmitted via DCI or higher-layer signaling" can also be described as being transmitted via unicast (or UE-specific transmission) and broadcast / multicast (or UE-general transmission) at least one of these methods.

[0034] (First method)

[0035] In the first approach, retransmission control for broadcast / multicast transmissions is explained.

[0036] Figure 1 This illustration shows an example of a base station sending specific information to multiple UEs (e.g., a group of UEs) using at least one of broadcast and multicast (hereinafter also referred to as broadcast / multicast). Here, it is shown that the base station broadcasts / multicasts to UE group #1 and UE group #2 respectively. In addition, the number of UE groups, the UEs constituting the UE groups, etc., can also be appropriately changed.

[0037] Each UE can also determine, based on specific information, whether or not it supports retransmission control for information transmitted via broadcast / multicast (or, whether or not it is applied or configured) (see reference). Figure 2The specific information may also be information notified using at least one of higher-layer signaling (option 1) and downlink control information (option 2) received from the network (e.g., a base station). Alternatively, the UE may determine the presence or absence of retransmission control based on specific rules (option 3).

[0038] <Option 1>

[0039] The UE can also determine whether or not to apply retransmission control for information transmitted via broadcast / multicast based on higher-layer signaling. The base station can notify each UE of the application of retransmission control using higher-layer signaling, or it can notify each group of UEs of the application of retransmission control.

[0040] When both broadcast transmission (e.g., transmission using a broadcast channel) and multicast transmission (e.g., transmission using a multicast channel) are supported, the presence or absence of retransmission control for broadcast transmission and the presence or absence of retransmission control for multicast transmission can be set separately. This allows for flexible control over the presence or absence of retransmission control.

[0041] Alternatively, when both broadcast and multicast transmissions are supported, the presence or absence of retransmission control for broadcast transmissions and the presence or absence of retransmission control for multicast transmissions can be set publicly. In this case, if the presence or absence of retransmission control is set for either broadcast or multicast transmissions, the UE can apply the same setting to the other. This simplifies the setting of retransmission control.

[0042] <Option 2>

[0043] The UE can also determine the presence or absence of retransmission control for information transmitted via broadcast / multicast based on downlink control information (e.g., DCI). The base station can notify each UE of the presence or absence of retransmission control using either a UE-specific DCI or a group-wide DCI. For example, when scheduling information transmitted via broadcast / multicast using DCI, information related to HARQ-ACK (e.g., presence or absence of the application, transmission timing, and information about at least one resource) can also be included in that DCI.

[0044] When both broadcast and multicast transmissions are supported, the presence or absence of retransmission control for broadcast transmissions and multicast transmissions can be configured separately. This allows for flexible control over the presence or absence of retransmission control applications.

[0045] Alternatively, if both broadcast and multicast transmissions are supported, the presence or absence of retransmission control for broadcast transmissions and the presence or absence of retransmission control for multicast transmissions can be set publicly. In this case, if the presence or absence of retransmission control is set for either broadcast or multicast transmissions, the UE can apply the same setting to the other. This simplifies the setting of retransmission control.

[0046] <Option 3>

[0047] The UE can also implicitly determine the presence or absence of retransmission control for information transmitted via broadcast / multicast based on specific rules. These specific rules can also be specific conditions set by transmission or reception (e.g., transmission conditions utilized in broadcast / multicast transmission). The following describes the case where the specific condition is repeated transmission (Case 1) and the case where the specific condition is at least one of a modulation and coding scheme (MCS) and a coding rate (Case 2). The specific conditions are not limited to these.

[0048] [Scenario 1]

[0049] When repetition is applied to information transmitted via broadcast / multicast, the UE can also determine that retransmission control (e.g., HARQ) is not supported or not applied. Conversely, if repetition is not applied, the UE can also determine that retransmission control is supported or applied.

[0050] The UE can also determine whether or not to apply retransmission control based on the number of repeated transmissions (also known as the retransmission factor). For example, the UE can choose not to apply retransmission control if the number of repeated transmissions is above a certain value (e.g., X), and apply retransmission control otherwise (e.g., if the number of transmissions is less than the certain value). The specific value (e.g., X) can be predefined in the specification or notified to the UE from the base station via higher-layer signaling.

[0051] The presence or absence of a repeatable application (or the number of repeatable transmissions) can also be set on a per-UE group basis. Alternatively, repeatable transmission (or the number of repeatable transmissions) can also be set on a per-UE basis. In the case of setting it on a per-UE basis, the presence or absence of a repeatable control application can also be set independently for each UE included in the UE group.

[0052] [Scenario 2]

[0053] The UE can also determine whether to apply retransmission control for the information transmitted via broadcast / multicast based on at least one of the MCS and coding rate applied in the information transmitted via broadcast / multicast (hereinafter, also referred to as MCS / coding rate).

[0054] For example, the UE may also not apply retransmission control when the MCS / coding rate corresponding to the information transmitted via broadcast / multicast is less than a specific value (e.g., Y), and apply retransmission control in other cases (e.g., the MCS / coding rate is greater than the specific value). The specific value (e.g., Y) may be predefined in the specification or notified to the UE from the base station via higher layer signaling or the like.

[0055] In this way, by controlling the application of retransmission control for broadcast / multicast transmission based on specific conditions, it is possible to flexibly control retransmission control based on the communication environment or communication conditions.

[0056] <HARQ process>

[0057] In retransmission control based on HARQ, retransmission control of data (transport block (TB) or code block (CB)) is performed with a process (HARQ process) as the processing unit. In the HARQ process with the same number (HARQ process number (HPN)), the same data is retransmitted until an ACK is received. The HARQ process number is also referred to as the HARQ process ID (HARQ process identifier).

[0058] In one time interval (e.g., time slot or subframe), one HARQ process can be used, or multiple HARQ processes can be used. By independently processing multiple HARQ processes in parallel, it is possible to transmit data of the next HARQ process without waiting for the A / N of the previous HARQ process, thus reducing the latency.

[0059] In retransmission control for broadcast / multicast transmission, retransmission control can also be performed based on the HARQ process. For example, X (or X number, X identifier) (X≥1) HARQ processes can be set for the information transmitted via broadcast / multicast. X may be predefined in the specification or notified to the UE from the base station via at least one of higher layer signaling and downlink control information.

[0060] When broadcast transmission and multicast transmission are both supported, X for broadcast transmission and X for multicast transmission can also be set separately. X for broadcast transmission and X for multicast transmission can also be set commonly. Alternatively, different X can be set for each broadcast transmission (or each multicast transmission).

[0061] In addition, consider the cases where the UE sends HARQ-ACK for unicast transmission and HARQ-ACK for broadcast / multicast transmission (see reference). Figure 3 ).exist Figure 3 The image shows an example of a UE reporting HARQ-ACK#B for broadcast / multicast transmissions and HARQ-ACK#A for unicast transmissions.

[0062] In this case, the HARQ process pool corresponding to information sent via unicast and the HARQ process pool corresponding to information sent via broadcast / multicast can also be set separately. The HARQ process pool can be either the processing operation of HARQ processes, or a value or range of HARQ process numbers.

[0063] For example, the HARQ process number for unicast transmission (e.g., HARQ-ACK#B) and the HARQ process number for broadcast / multicast transmission (e.g., HARQ-ACK#A) can also be set separately. The UE can also control the retransmission of unicast transmission based on the HARQ process number for unicast transmission, and the UE can also control the retransmission of broadcast / multicast transmission based on the HARQ process number for broadcast / multicast transmission.

[0064] In this way, by setting up separate HARQ process pools for information sent via unicast and information sent via broadcast / multicast, it is possible to avoid conflicts between HARQ processes sent via unicast and those sent via broadcast / multicast.

[0065] Alternatively, the HARQ processes pool corresponding to messages sent via unicast and the HARQ processes pool corresponding to messages sent via broadcast / multicast can also be set up in a shared manner.

[0066] In this case, a common HARQ process number (e.g., X HARQ processes) can also be applied to the HARQ process used for unicast transmission and the HARQ process used for broadcast / multicast transmission.

[0067] The network (e.g., a base station) can also control HARQ process processing to prevent conflicts between HARQ processes for information transmitted via unicast and information transmitted via broadcast / multicast. For example, at least one of the base station and the UE can also control the process so that HARQ process numbers assigned to one side for unicast transmission and one side for broadcast / multicast transmission are not assigned to the other side.

[0068] Alternatively, priorities can be set for HARQ processes (e.g., a priority rule), and retransmission control can be performed based on this priority in the event of a HARQ process conflict. For example, broadcast / multicast transmissions can have a higher priority than unicast transmissions. In the event of a conflict between the HARQ process corresponding to unicast transmissions and the HARQ process corresponding to broadcast / multicast transmissions, the UE can also prioritize retransmission control for the HARQ process corresponding to broadcast / multicast transmissions.

[0069] The priority of HARQ processes can also be set based on other conditions. For example, the priority of HARQ processes can also be determined based on the service (or business type). As an example, the priority of HARQ processes corresponding to the first business type (e.g., URLLC) can be set higher than that of HARQ processes corresponding to the second business type (e.g., eMBB).

[0070] Additionally, when the number of HARQ processes is 1 (X = 1), the scheduling information may not include information specifying the HARQ process number. For example, when X = 1, in a DCI that schedules at least one of the control information and data sent via multicast / broadcast, the field for HARQ process notification may be omitted or used for other purposes. Otherwise (X > 1), in this DCI, an n-bit field (e.g., n = log2(X)) may be set to notify the HARQ process ID corresponding to the multicast / broadcast transmission.

[0071] <Soft Buffer>

[0072] The UE may also have a buffer (soft buffer) to temporarily store received data that has failed to be decoded. The received data may also be stored in the soft buffer on a per HPN basis (e.g., a block group (CBG) containing TB, code block, or more than one code block).

[0073] In addition, the UE can also perform soft combining on received data (or retransmitted data) based on the same repeatedly transmitted HPN. Furthermore, the user terminal can also perform soft combining on data stored in the soft buffer and received data from the same HPN. Soft combining refers to assigning the same HPN to multiple data generated from the same information bit string and transmitting them, with the receiver combining the multiple data from the same HPN.

[0074] The soft buffer on the UE side for the information sent via unicast and the soft buffer on the UE side for the information sent via broadcast / multicast can also be set in a shared manner. In this case, even when the decoding of one of the transmissions fails continuously, the soft buffer can be utilized effectively.

[0075] Alternatively, the soft buffer on the UE side for the information sent via unicast and the soft buffer on the UE side for the information sent via broadcast / multicast can also be set separately. For example, in the UE, the soft buffer for broadcast / multicast transmission can also be set separately from the soft buffer used in unicast transmission. Thereby, the situation where the failure of decoding of one of the transmissions affects the soft buffer of the other transmission can be suppressed.

[0076] (Second method)

[0077] In the second method, the feedback control of the delivery confirmation signal (or also referred to as the retransmission control signal, HARQ-ACK) for broadcast / multicast transmission is described.

[0078] <HARQ-ACK transmission timing>

[0079] The UE feeds back the HARQ-ACK for the information sent via broadcast / multicast at a specific timing (e.g., K1) (refer to Figure 4 ). In Figure 4 , it shows the situation where the UEs included in UE group #1 feed back the HARQ-ACK at a specific timing (e.g., K 11 , K 12 ), and the UEs included in UE group #2 feed back the HARQ-ACK at a specific timing (e.g., K 21 , K 22 ).

[0080] The specific timing can be defined by a fixed value or notified from the network (e.g., the base station). For example, the UE can also apply at least any one of the following options 2-1 to 2-3 to determine the transmission timing of the HARQ-ACK.

[0081] [Option 2-1]

[0082] As the transmission timing of the HARQ-ACK for broadcast / multicast transmission, one timing value (one value) can also be applied. This one timing value can be defined in the specification or notified to the UE from the base station via high-layer signaling, etc. The UE can also determine the transmission timing of the HARQ-ACK for broadcast / multicast transmission based on this one timing value (e.g., the fixed value K1).

[0083] For example, in Figure 4 In, it can also be K. 11 =K 12 =K 21 =K 22 = Fixed value K1. Alternatively, one timing value can be set for each UE group. For example, in Figure 4 In, it can also be K. 11 =K 12 = Fixed value K A K 21 =K 22 = Fixed value K B .

[0084] For multiple UEs within a specific UE group that receive information transmitted via broadcast / multicast, the HARQ-ACK feedback timing can also be set commonly (e.g., the same value). For example, in Figure 4 In, it can also be at least K. 11 =K 12 K 21 =K 22 This enables consistent timing of HARQ-ACK feedback from multiple UEs within a specific UE group.

[0085] Alternatively, the HARQ-ACK feedback timing can also be set independently (e.g., to different values) to multiple UEs within a specific UE group. For example, in Figure 4 In, it can also be at least K. 11 ≠K 12 K 21 ≠K 22 In this scenario, the timing of HARQ-ACK feedback from multiple UEs within a specific UE group can be distributed. Alternatively, the same value can be set for a subset of the multiple UEs within a specific group, while different values ​​can be set for the other UEs.

[0086] [Option 2-2]

[0087] Alternatively, the structure can be configured as follows, setting a set of transmission timing values ​​for HARQ-ACK for broadcast / multicast transmission (or, also called a combination of transmission timing values, multiple transmission timing candidates, or a set of transmission timing candidates), and selecting a specific transmission timing value from the set. The set of HARQ-ACK transmission timing values ​​can be predefined in the specification or notified to the UE from the base station using higher-layer signaling, etc.

[0088] Furthermore, the base station can also send information specifying a particular transmission timing value from the set of HARQ-ACK transmission timing values ​​to the UE. For example, the base station can also include the information specifying a particular transmission timing value in the downlink control information and send it to the UE. The UE can also determine the HARQ-ACK transmission timing value based on the bit information contained in the downlink control information.

[0089] Downlink control information (e.g., group common PDCCH) can also be sent to multiple UEs (e.g., UEs included in a specific group). In this case, all UEs included in the specific group can use the same timing to send HARQ-ACK responses.

[0090] [Options 2-3]

[0091] The base station can also set the first transmission timing parameter (e.g., offset (e.g., T_delta, or ΔT)) for the transmission timing of HARQ-ACK to each UE. For example, the base station can also use higher-layer signaling to set the offset of the transmission timing of HARQ-ACK to the UE. In this case, the offset can be set separately for each UE (e.g., different offsets) or the offset can be set for each group (e.g., a common offset for a specific group).

[0092] Furthermore, the base station can also use downlink control information to notify the UE of information related to the second transmission timing parameter (e.g., the transmission timing of HARQ-ACK). For example, the base station can also use a DCI (or PDCCH) that schedules broadcast / multicast transmissions, or a group common DCI (or group common PDCCH), to notify multiple UEs of the same transmission timing (e.g., K1). Alternatively, the base station can also use a UE-specific DCI (or UE-specific PDCCH) to notify each UE of the transmission timing separately.

[0093] Each UE determines the transmission timing of HARQ-ACK (e.g., K1+T_delta) based on a first transmission timing parameter (e.g., T_delta) notified via higher-layer signaling and a second transmission timing parameter (e.g., transmission timing K1) notified via DCI. Thus, by notifying at least one of the first and second parameters (e.g., an offset) on a UE-specific basis, transmission timing can be flexibly controlled among UEs even if the other is set commonly by UE group.

[0094] In addition, the transmission timing of HARQ-ACK for unicast transmission and the transmission timing of HARQ-ACK for broadcast / multicast transmission can also be set separately (e.g., using different methods). Thereby, the feedback timing of HARQ-ACK can be flexibly controlled according to each transmission.

[0095] <HARQ-ACK feedback resource>

[0096] The UE can also determine at least one of the resources and formats (hereinafter also referred to as resources / formats) used in the feedback of HARQ-ACK for broadcast / multicast transmission based on specific information. For example, the UE can also apply at least any one of the following options 3-1 to 3-3 to determine the resources / formats for HARQ-ACK. In addition, the transmission timing of HARQ-ACK can apply any one of the above options 2-1 to 2-3.

[0097] [Option 3-1]

[0098] The base station can also use higher layer signaling to notify each UE of information related to the resources / formats of a specific channel (e.g., PUCCH) used in HARQ-ACK transmission. The resources / formats of the PUCCH notified to each UE can also be set separately (e.g., different resources / formats are set) for each UE.

[0099] Alternatively, the base station can also use higher layer signaling to notify each UE group of information related to the resources / formats of the PUCCH used in HARQ-ACK transmission. That is, the resources / formats of the PUCCH can also be set in units of UE groups. In this case, UEs included in the same group can also use the same resources / formats to perform HARQ-ACK transmission.

[0100] In Option 3-1, the UE can determine the resources / formats used in HARQ-ACK transmission based on the information notified via higher layer signaling (without using L1 signaling).

[0101] [Option 3-2]

[0102] The base station can also use higher layer signaling to notify each UE of the parameters of the first resources / formats. The parameters of the first resources / formats can also be information related to the resource index (e.g., PUCCH_index) of a specific channel (e.g., PUCCH) used in HARQ-ACK transmission. The resource index of the PUCCH can also be set separately (e.g., different resource indexes) for each UE.

[0103] Furthermore, the base station can also assign multiple sets of PUCCH resources (also known as multiple PUCCH resource candidate sets) to the UE via higher-layer signaling. Further, the base station can also include information specifying a particular set from the multiple sets in downlink control information and send it to the UE. This particular set is also referred to as a second resource / format parameter.

[0104] For example, a base station may use a DCI (or PDCCH) that schedules broadcast / multicast transmissions, or a group-common DCI (or group-common PDCCH), to notify multiple UEs of a specific set. Alternatively, the base station may use a UE-specific DCI (or UE-specific PDCCH) to notify each UE of a specific set separately.

[0105] Each UE can also determine the PUCCH resource / format based on parameters of a first resource / format notified via higher-layer signaling and parameters of a second resource / format specified using at least one of DCI and higher-layer signaling. For example, a UE can also determine the PUCCH resource / format from a set of specific PUCCH resources specified via downlink control information based on a PUCCH resource index notified via higher-layer signaling.

[0106] By notifying at least one of the first resource / format parameter and the second resource / format parameter (e.g., PUCCH resource index) specifically on a UE basis, different PUCCH resources can be used among UEs even if the other is set commonly on a UE group basis.

[0107] [Option 3-3]

[0108] The base station can also assign multiple PUCCH resources (also known as PUCCH resource candidates) to the UE via higher-layer signaling. Furthermore, the base station can also send downlink control information (DCI) containing information specifying a particular PUCCH resource from among multiple PUCCH resources to the UE (e.g., multiple UEs within a specific group). The downlink control information can be either a DCI transmitted via a group common PDCCH or a DCI scheduling broadcast / multicast transmissions.

[0109] In this case, the same PUCCH resource can also be assigned to multiple UEs within a specific group.

[0110] (Third method)

[0111] In the third mode, transmission power control of an uplink channel (e.g., at least one of PUCCH and PUSCH) used in the transmission of HARQ-ACK for broadcast / multicast transmission is described. In the following description, PUCCH is taken as an example of the uplink channel used in the transmission of HARQ-ACK, but the same can also be applied to other uplink channels (e.g., PUSCH).

[0112]

[0113] In Rel.15, the UE performs transmission power control (TPC) for each transmission occasion i. The transmission occasion i can also be a transmission occasion of PUSCH, PUCCH, SRS, or PRACH. The transmission occasion i can also be defined by the slot index n for the subcarrier spacing configuration μ within a frame with a system frame number (SFN) s，f μ 、the first symbol within that slot (index of the first symbol of the transmission occasion i) S, and the number of consecutive symbols L.

[0114] The transmission power of PUCCH can also be controlled based on the TPC command (also referred to as value, increment / decrement value, correction value, indication value, etc.) indicated by the value of a specific field (also called TPC command field, first field, etc.) within DCI.

[0115] For example, the transmission power (P PUCCH、b，f，c (i, q u , q d , l)) of PUCCH in a transmission occasion (also called transmission period, etc.) i related to the BWP b of the carrier f of the cell c using the index l of the power control adjustment state can also be represented by the following equation (1).

[0116] Here, the power control adjustment state can also be set via higher-level parameters to have multiple states (e.g., two states) or a single state. Furthermore, if multiple power control adjustment states are set, one of these states can be identified by an index l (e.g., l ∈ {0, 1}). The power control adjustment state can also be referred to as the PUCCH power control adjustment state, the first state, or the second state, etc.

[0117] Furthermore, the transmission opportunity i of PUCCH is a specific period during which PUCCH is transmitted; for example, it can also consist of more than one symbol, more than one time slot, etc.

[0118] [Number 1]

[0119] Equation (1)

[0120]

[0121] In equation (1), P CMAX，f，c (i) For example, the transmit power (also known as maximum transmit power, etc.) of the user terminal used by the carrier f of cell c in transmission opportunity i. O_PUCCH，b，f，c (q u For example, it is a parameter related to the target received power of the BWP b of the carrier f of cell c in transmission opportunity i (e.g., also referred to as a parameter related to the transmit power offset, transmit power offset P0, or target received power parameter, etc.).

[0122] M PUCCH RB，b，f，c (i) For example, the number of resource blocks (bandwidth) allocated to the PUCCH for the transmission opportunity i in the uplink BWP b of cell c and carrier f with subcarrier spacing μ. b，f，c (q d For example, the index q of the reference signal used for the downlink BWP associated with the uplink BWP b of the carrier f of cell c. d The path loss is calculated through the user terminal.

[0123] Δ F_PUCCH (F) is a high-level parameter given for each PUCCH format. Δ TF,b,f,c (i) is the transmission power adjustment component (offset) used by the uplink BWP b of carrier f in cell c.

[0124] g b，f，c(i, l) is the value of the TPC command (e.g., power control adjustment state, accumulated value of TPC command) based on the uplink BWP of the carrier f of cell c and transmission opportunity i. For example, the accumulated value of TPC command can also be represented by a specific formula.

[0125] TPC commands can also be determined based on the values ​​of specific fields (also known as TPC command fields, first fields, etc.) within the DCI used in the scheduling of PUSCH or PDSCH. Power control information can also be referred to as TPC commands (also known as values, increment / decrease values, correction values, etc.).

[0126] Furthermore, Equation (1) is merely an example and is not limited to it. The user terminal can control the transmission power of the PUCCH based on at least one of the parameters illustrated in Equation (1). Additional parameters may also be included, and some parameters may be omitted. In addition, in the above Equation (1), the transmission power of the PUCCH is controlled for each BWP of a certain carrier in a certain cell, but it is not limited to this. At least some of the cell, carrier, BWP, and power control adjustment state may also be omitted.

[0127] The UE applies a specific transmit power (or a specific transmit power parameter) to the PUCCH (reference) used in the feedback of HARQ-ACK for broadcast / multicast transmissions. Figure 5 ).exist Figure 5 The image shows UEs included in UE group #1 applying a specific transmit power (e.g., P). 11 P 12 The UEs in UE group #2 use the PUCCH to provide HARQ-ACK feedback, and apply a specific transmit power (e.g., P) to the UEs. 21 P 22 The PUCCH is used to provide feedback on the HARQ-ACK status.

[0128] The UE can also determine a specific transmit power based on specific information. For example, the UE can also apply at least one of the following options 4-1 to 4-2 to determine the transmit power.

[0129] [Option 4-1]

[0130] The UE can also determine the PUCCH transmission power based on parameters set via higher-layer signaling (also known as transmission power parameters). The parameters set via higher-layer signaling can be either the parameters included in the above equation (1) (e.g., a combination of P0 and α) or other parameters.

[0131] Furthermore, within a specific group of UEs that are transmitting the same information via broadcast / multicast, the transmit power parameter can be set separately (e.g., different transmit power parameters). That is, the transmit power parameter can be set independently for each UE. For example, in... Figure 5 In the middle, P 11 and P 12 (or, P) 21 and P 22 They are set separately.

[0132] Furthermore, within a specific group of UEs that are transmitting the same information via broadcast / multicast, the transmission timing value can be set separately. This allows for flexible control of transmission power, taking into account interference and other factors, among different UEs.

[0133] [Option 4-2]

[0134] The base station can also use higher-layer signaling to set a first transmit power parameter to each UE. The first transmit power parameter can be set commonly to multiple UEs (e.g., a group of UEs) or separately (e.g., different values) to each UE. The first transmit power parameter can also be, for example, a power offset (e.g., P_delta, or P...). Δ ).

[0135] In addition, the base station can also notify the UE of the second transmit power parameter using at least one of higher-layer signaling and DCI. The second parameter can also be a power control value (e.g., P_M, or P...). M For example, the base station may also use higher-layer signaling to set a set of second transmit power parameters (e.g., multiple candidate values ​​of the second parameter, or a candidate set of the second parameter) to the UE, and use DCI to notify the UE of the specific second parameter.

[0136] For example, the base station may use a DCI (or PDCCH) that schedules broadcast / multicast transmissions, or a group-common DCI (or group-common PDCCH), to notify multiple UEs of a specific second parameter. Alternatively, the base station may use a UE-specific DCI (or UE-specific PDCCH) to notify each UE of the specific second parameter separately.

[0137] Each UE can also adjust the PUCCH transmission power based on a first transmission power parameter notified via higher-layer signaling and a second transmission power parameter (e.g., P_delta+P_M) specified using at least one of DCI and higher-layer signaling.

[0138] By notifying at least one of the first and second transmit power parameters (e.g., P_delta) specifically for each UE, different transmit power can be used among UEs even if the other is set commonly by UE group.

[0139] [Option 4-3]

[0140] Each UE can also adjust the PUCCH transmission power based on TPC commands. For example, in addition to options 4-1 or 4-2, the UE can also consider TPC commands to determine the PUCCH transmission power.

[0141] TPC commands can also be included in a DCI that schedules broadcast / multicast transmissions. Alternatively, TPC commands can be included in a different DCI than the one that schedules broadcast / multicast transmissions. The DCI that sends TPC commands can be sent either through a UE-specific DCI or through a common DCI (e.g., a group common PDCCH) on a UE-specific basis.

[0142] (Fourth method)

[0143] In the fourth method, the transmission control of HARQ-ACK for broadcast / multicast transmissions is explained.

[0144] In HARQ-based retransmission control, the UE sends an ACK if the data reception and processing (e.g., decoding) is successful, and sends a NACK if it fails. For retransmission control of information transmitted via broadcast / multicast, the UE may also apply at least any one of the following options 5-1 to 5-2.

[0145] [Option 5-1]

[0146] The UE can also control the reporting of only one party's report (e.g., NACK) as a HARQ-ACK for broadcast / multicast transmissions. For example, the UE can also control the reporting of NACK if decoding of information transmitted via broadcast / multicast fails, but not ACK if decoding succeeds (see reference). Figure 6 ).

[0147] exist Figure 6 The diagram illustrates the scenarios where UEs in UE group #1 send NACK when decoding of information transmitted via broadcast / multicast fails, and UEs in UE group #2 send NACK when decoding of information transmitted via broadcast / multicast fails. Alternatively, control can be implemented to prevent the sending of ACK when decoding is successful.

[0148] The base station can also determine that data reception was successful for UEs that do not report NACK. NACK detection in the base station can also be based on power detection (also known as energy detection). For example, the base station can also use the same mechanism as the detection of scheduling requests (SRs) sent via PUCCH to perform NACK detection.

[0149] Furthermore, the resources for NACK reports by each UE can be shared among multiple UEs. That is, a UE sending a NACK for broadcast / multicast transmission can also use the same UL channel resources (e.g., PUCCH resources) to send the NACK. The resources used for this NACK reporting can be defined in the specification or notified to each UE (or UE group) from the base station using at least one of downlink control information and higher-layer signaling.

[0150] For example, in Figure 6 In the case where multiple UEs in UE group #1 send NACK, they can also use the same UL channel resources (e.g., resources with the same time and frequency domains) to send NACK. Similarly, in the case where multiple UEs in UE group #2 send NACK, they can also use the same UL channel resources (e.g., resources with the same time and frequency domains) to send NACK.

[0151] In this way, by publicly allocating the resources used for NACK reporting to multiple UEs (e.g., the same UE group), it is possible to improve resource utilization efficiency.

[0152] The base station can also perform retransmission control (e.g., determining whether a retransmission is possible) based on the presence or absence of NACK reports detected in the resources used for NACK. For example, the base station envisions a situation where NACK is detected in the resources allocated to UE group #1. This means that at least one UE in UE group #1 (a UE that was transmitted via broadcast / multicast) has failed to decode.

[0153] In this scenario, the base station can also retransmit information (e.g., transport blocks) via broadcast / multicast. The UE can also control whether or not to receive the retransmitted information based on its own reception status. For example, a UE that has reported a NACK can control the reception of the retransmitted information. On the other hand, a UE that has not reported a NACK (e.g., a UE that has successfully decoded the data) can skip the reception processing (e.g., decoding) of the retransmitted information.

[0154] In this way, by controlling whether or not retransmitted information is received based on the reception status, it is possible to suppress the increase in the load on the UE's reception processing.

[0155] Additionally, the above description illustrates the case where only NACK is reported, but it is not limited to this. It can also be configured to only send ACK.

[0156] [Option 5-2]

[0157] The UE can also control the reporting of at least one of ACK and NACK as a HARQ-ACK for broadcast / multicast transmissions. For example, the UE can also control the reporting of NACK if decoding of information transmitted via broadcast / multicast fails, and ACK if decoding succeeds. Alternatively, similar to option 5-1 above, the UE can also control the reporting of NACK if decoding fails, and not report ACK if decoding succeeds.

[0158] The resources used by each UE in at least one of the ACK and NACK reports (hereinafter also referred to as ACK / NACK) can also be separately (e.g., UE-specific) allocated to each UE (see reference). Figure 7 ).exist Figure 7 The diagram illustrates how UEs in UE group #1 send ACK / NACK for broadcast / multicast transmissions using different resources, and how UEs in UE group #2 send ACK / NACK for broadcast / multicast transmissions using different resources. Alternatively, a UE may only report NACK (reporting only in the event of decoding failure).

[0159] In this way, different ACK / NACK reporting resources (e.g., at least one different resource in the time domain, frequency domain, and symbol domain) can be set for multiple UEs belonging to the same UE group. The ACK / NACK reporting resources can also be notified to each UE from the base station using at least one of downlink control information and higher-layer signaling.

[0160] The base station can also perform retransmission control for each UE individually based on the presence or absence of ACK / NACK detection in the resources allocated to each UE (e.g., determining whether retransmission is required). For example, the base station can also retransmit only to UEs that have reported NACK. In this case, the base station can also use unicast transmission to selectively retransmit retransmission information (e.g., transport blocks) for information sent via broadcast / multicast to specific UEs.

[0161] Therefore, retransmission can be performed only for UEs whose decoding of information sent via broadcast / multicast fails. As a result, UEs that successfully decode do not need to receive the retransmitted information, thus suppressing the increase in the receiving processing load of those UEs.

[0162] Alternatively, the base station can determine the retransmission method based on the number of UEs that have received a NACK (or an ACK). For example, if the number of UEs reporting NACKs is above a certain value (or the number of UEs reporting ACKs is below a certain value), retransmission can be performed via broadcast / multicast. In this case, UEs that have not reported NACKs (or UEs that have reported ACKs) can skip the reception processing (e.g., decoding) of the retransmitted information.

[0163] (Wireless Communication System)

[0164] The structure of a wireless communication system according to one embodiment of this disclosure will be described below. In this wireless communication system, communication is performed using one or a combination of the wireless communication methods according to the above embodiments of this disclosure.

[0165] Figure 8 This is a diagram illustrating an example of the schematic structure of a wireless communication system according to one embodiment. The wireless communication system 1 may also be a system that uses Long Term Evolution (LTE) or 5th generation mobile communication system New Radio (5G NR) as standardized by the Third Generation Partnership Project (3GPP).

[0166] Furthermore, the wireless communication system 1 can also support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC can 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)), etc.

[0167] In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (MN), and the NR base station (gNB) is the secondary node (SN). In NE-DC, the NR base station (gNB) is the MN, and the LTE (E-UTRA) base station (eNB) is the SN.

[0168] Wireless communication system 1 can also support dual connectivity between multiple base stations within the same RAT (e.g., MN and SN are dual connectivity of NR base stations (gNB) (NR-NR Dual Connectivity (NN-DC))).

[0169] The wireless communication system 1 may also include: a base station 11 forming a macro cell C1 with a relatively wide coverage area, and a base station 12 (12a-12c) configured within the macro cell C1 and forming a small cell C2 narrower than the macro cell C1. User terminals 20 may also be located within at least one cell. The configuration and number of each cell and user terminal 20 are not limited to the arrangement shown in the figure. Hereinafter, without distinguishing between base stations 11 and 12, they will be collectively referred to as base station 10.

[0170] User terminal 20 may also connect to at least one of multiple base stations 10. User terminal 20 may also utilize at least one of carrier aggregation (CA) using multiple component carriers (CC) and dual connectivity (DC).

[0171] Each CC can also be included in at least one of the first frequency band (Frequency Range 1 (FR1)) and the second frequency band (Frequency Range 2 (FR2)). Macro cell C1 can also be included in FR1, and small cell C2 can also be included in FR2. For example, FR1 can also be a frequency band below 6 GHz (sub-6 GHz), and FR2 can also be a frequency band above 24 GHz (above-24 GHz). In addition, the frequency bands, definitions, etc. of FR1 and FR2 are not limited to these; for example, FR1 can also correspond to a frequency band higher than FR2.

[0172] In addition, user terminal 20 can also communicate in each CC using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD).

[0173] Multiple base stations 10 can also be connected via wired (e.g., fiber optic cable based on the Common Public Radio Interface (CPRI), X2 interface, etc.) or wireless (e.g., NR communication). For example, when NR communication between base stations 11 and 12 is used as a backhaul, base station 11, which is equivalent to a host station, can also be called an Integrated Access Backhaul (IAB) donor, and base station 12, which is equivalent to a relay station, can also be called an IAB node.

[0174] Base station 10 may also be connected to core network 30 via other base stations 10 or directly. Core network 30 may include, for example, at least one of Evolved Packet Core (EPC), 5G Core Network (5GCN), Next Generation Core (NGC), etc.

[0175] User terminal 20 can also be a terminal that supports at least one of the following communication methods: LTE, LTE-A, 5G, etc.

[0176] In wireless communication system 1, wireless access methods based on Orthogonal Frequency Division Multiplexing (OFDM) can also be used. For example, in at least one of the downlink (DL) and uplink (UL) links, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access (SC-FDMA) can also be used.

[0177] The wireless access method can also be referred to as a waveform. In addition, in the wireless communication system 1, other wireless access methods (e.g., other single-carrier transmission methods, other multi-carrier transmission methods) can also be used in the wireless access methods of UL and DL.

[0178] In the wireless communication system 1, the downlink channel can also be a shared downlink channel (Physical Downlink Shared Channel (PDSCH)), a broadcast channel (Physical Broadcast Channel (PBCH)), or a downlink control channel (Physical Downlink Control Channel (PDCCH)) shared by each user terminal 20.

[0179] In addition, in the wireless communication system 1, the uplink channel can also be an uplink shared channel (Physical Uplink Shared Channel (PUSCH)), an uplink control channel (Physical Uplink Control Channel (PUCCH)), or a random access channel (Physical Random Access Channel (PRACH)) shared by each user terminal 20.

[0180] User data, high-level control information, and System Information Blocks (SIBs) are transmitted via PDSCH. User data and high-level control information can also be transmitted via PUSCH. Furthermore, Master Information Blocks (MIBs) can be transmitted via PBCH.

[0181] Lower-layer control information can also be transmitted via PDCCH. This lower-layer control information may include, for example, downlink control information (DCI), which contains scheduling information for at least one of PDSCH and PUSCH.

[0182] Additionally, the DCI for scheduling PDSCH can also be called DL allocation, DL DCI, etc., and the DCI for scheduling PUSCH can also be called UL authorization, UL DCI, etc. Furthermore, PDSCH can be replaced with DL data, and PUSCH can be replaced with UL data.

[0183] In PDCCH detection, a Control Resource Set (CORESET) and a search space can be utilized. A CORESET corresponds to the resources used to search for DCIs. The search space corresponds to the search area and search method for PDCCH candidates. A CORESET can be associated with one or more search spaces. The UE can also monitor CORESETs associated with a specific search space based on search space settings.

[0184] A search space can also correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces can also be called a search space set. In addition, the terms "search space", "search space set", "search space setting", "search space set setting", "CORESET", and "CORESET setting" in this disclosure can be used interchangeably.

[0185] Uplink control information (UCI) can also be transmitted via PUCCH, including at least one of the following: Channel State Information (CSI), delivery confirmation information (e.g., also known as Hybrid Automatic Repeat Request ACK Knowledgement (HARQ-ACK), ACK / NACK, etc.), and Scheduling Request (SR). Random access preambles used for establishing a connection with the cell can also be transmitted via PRACH.

[0186] Additionally, in this disclosure, downlink, uplink, etc., may be described without the word "link". Furthermore, it may be described without "physical" at the beginning of various channels.

[0187] In wireless communication system 1, synchronization signals (SS) and downlink reference signals (DL-RS) can also be transmitted. In wireless communication system 1, as DL-RS, cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), demodulation reference signals (DMRS), positioning reference signals (PRS), and phase tracking reference signals (PTRS) can also be transmitted.

[0188] Synchronization signals can be, for example, at least one of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). A signal block containing SS (PSS, SSS) and PBCH (and DMRS for PBCH) can also be called an SS / PBCH block, SS block (SSB), etc. In addition, SS, SSB, etc. can also be called reference signals.

[0189] Furthermore, in the wireless communication system 1, the uplink reference signal (UL-RS) can also transmit measurement reference signals (sounding reference signals (SRS)) and demodulation reference signals (DMRS). Additionally, DMRS can also be referred to as a user terminal-specific reference signal (UE-specific reference signal).

[0190] (Base station)

[0191] Figure 9This diagram illustrates an example of the structure of a base station according to one embodiment. The base station 10 includes a control unit 110, a transmit / receive unit 120, a transmit / receive antenna 130, and a transmission path interface (transmission line interface) 140. Alternatively, the control unit 110, the transmit / receive unit 120, the transmit / receive antenna 130, and the transmission path interface 140 may each be provided in more than one manner.

[0192] Furthermore, in this example, only the functional blocks of the characteristic parts of this embodiment are shown. The base station 10 can also be conceived to have other functional blocks required for wireless communication. Some of the processing of each unit described below can also be omitted.

[0193] The control unit 110 performs overall control of the base station 10. The control unit 110 can be composed of a controller, control circuit, etc., which are described based on common knowledge in the art to which this disclosure pertains.

[0194] The control unit 110 can also control signal generation and scheduling (e.g., resource allocation, mapping). The control unit 110 can also control transmission, reception, and measurement using the transmit / receive unit 120, transmit / receive antenna 130, and transmission path interface 140. The control unit 110 can also generate data, control information, sequences, etc., to be transmitted as signals and forward them to the transmit / receive unit 120. The control unit 110 can also perform call processing (setting, releasing, etc.) of the communication channel, status management of the base station 10, and management of wireless resources.

[0195] The transmitting / receiving 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 transmitting processing unit 1211 and a receiving processing unit 1212. The transmitting / receiving unit 120 can be composed of transmitters / receivers, RF circuits, baseband circuits, filters, phase shifters, measurement circuits, transmitting / receiving circuits, etc., as described based on common knowledge in the art to which this disclosure pertains.

[0196] The transmitting and receiving unit 120 can be configured as a single integrated transmitting and receiving unit, or it can be configured as a transmitting unit and a receiving unit. The transmitting unit can also be configured as a transmitting processing unit 1211 and an RF unit 122. The receiving unit can also be configured as a receiving processing unit 1212, an RF unit 122, and a measurement unit 123.

[0197] The transmitting and receiving antenna 130 can be constructed from an antenna, such as an array antenna, as described based on common knowledge in the art to which this disclosure pertains.

[0198] The transmitting / receiving unit 120 can also transmit the aforementioned downlink channel, synchronization signal, downlink reference signal, etc. The transmitting / receiving unit 120 can also receive the aforementioned uplink channel, uplink reference signal, etc.

[0199] The transmitting and receiving unit 120 may also use digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc., to form at least one of the transmitting beam and the receiving beam.

[0200] The transmitting and receiving unit 120 (transmitting processing unit 1211) may, for example, perform processing at the Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer (e.g., RLC retransmission control), and Medium Access Control (MAC) layer (e.g., HARQ retransmission control) on the data and control information obtained from the control unit 110, and generate a bit string to be transmitted.

[0201] The transmitting and receiving unit 120 (transmitting processing unit 1211) can also perform transmission processing such as channel coding (which may also include error correction coding), modulation, mapping, filter processing, Discrete Fourier Transform (DFT) processing (as needed), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output the baseband signal.

[0202] The transmitting and receiving unit 120 (RF unit 122) can also perform modulation, filtering, amplification, etc. on the baseband signal to the wireless frequency band, and transmit the wireless frequency band signal through the transmitting and receiving antenna 130.

[0203] On the other hand, the transmitting and receiving unit 120 (RF unit 122) can also amplify, filter, demodulate, etc., the signals of the wireless frequency band received by the transmitting and receiving antenna 130.

[0204] The transmitting and receiving unit 120 (receiving and processing unit 1212) can also perform receiving and processing on the acquired baseband signal, including analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (as needed), filter processing, demapping, demodulation, decoding (which may also include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing, to obtain user data.

[0205] The transmitting / receiving unit 120 (measurement unit 123) can also perform measurements related to the received signal. For example, the measurement unit 123 can also perform radio resource management (RRM) measurements, channel state information (CSI) measurements, etc., based on the received signal. The measurement unit 123 can also measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results can also be output to the control unit 110.

[0206] The transmission path interface 140 can also transmit and receive signals (backhaul signaling) between the device included in the core network 30 and other base stations 10, and can also acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

[0207] In addition, the transmitting unit and receiving unit of the base station 10 in this disclosure may also be composed of at least one of a transmitting / receiving unit 120, a transmitting / receiving antenna 130, and a transmission path interface 140.

[0208] In addition, the transmitting and receiving unit 120 transmits specific information using at least one of broadcasting and multicasting. The transmitting and receiving unit 120 can also receive retransmission control information for specific information transmitted using at least one of broadcasting and multicasting.

[0209] The control unit 110 can also control the UE to set whether or not an application for retransmission control of specific information sent using at least one of broadcast and multicast is enabled.

[0210] In addition, the control unit 110 can also perform control to set the transmission timing for retransmission control of specific information transmitted using at least one of the broadcast and multicast methods to the UE.

[0211] In addition, the control unit 110 can also perform control to set the transmission power for retransmission control of specific information transmitted using at least one of broadcast and multicast to the UE.

[0212] In addition, the control unit 110 can also perform control to allocate resources to the UE for retransmission control of specific information sent using at least one of the broadcast and multicast methods.

[0213] (User terminal)

[0214] Figure 10 This diagram illustrates an example of the structure of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transmitting / receiving unit 220, and a transmitting / receiving antenna 230. Alternatively, more than one of each of the control unit 210, the transmitting / receiving unit 220, and the transmitting / receiving antenna 230 may be included.

[0215] Furthermore, in this example, only the functional blocks of the characteristic parts of this embodiment are shown. The user terminal 20 can also be conceived to have other functional blocks required for wireless communication. Some of the processing of each unit described below can also be omitted.

[0216] The control unit 210 performs overall control of the user terminal 20. The control unit 210 can be composed of a controller, control circuit, etc., which are described based on common knowledge in the art to which this disclosure pertains.

[0217] The control unit 210 can also control signal generation, mapping, etc. The control unit 210 can also control transmission, reception, measurement, etc., using the transmission / reception unit 220 and the transmission / reception antenna 230. The control unit 210 can also generate data, control information, sequences, etc., to be transmitted as signals and forward them to the transmission / reception unit 220.

[0218] The transmitting / receiving 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 transmitting processing unit 2211 and a receiving processing unit 2212. The transmitting / receiving unit 220 may be composed of a transmitter / receiver, RF circuit, baseband circuit, filter, phase shifter, measurement circuit, transmitting / receiving circuit, etc., as described based on common knowledge in the art to which this disclosure pertains.

[0219] The transmitting and receiving unit 220 can be configured as a single integrated transmitting and receiving unit, or it can be composed of a transmitting unit and a receiving unit. The transmitting unit can also be composed of a transmitting processing unit 2211 and an RF unit 222. The receiving unit can also be composed of a receiving processing unit 2212, an RF unit 222, and a measurement unit 223.

[0220] The transmitting and receiving antenna 230 can be constructed from an antenna, such as an array antenna, as described based on common knowledge in the art to which this disclosure pertains.

[0221] The transmitting / receiving unit 220 can also receive the downlink channel, synchronization signal, downlink reference signal, etc., mentioned above. The transmitting / receiving unit 220 can also transmit the uplink channel, uplink reference signal, etc., mentioned above.

[0222] The transmitting and receiving unit 220 may also use digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc., to form at least one of the transmitting beam and the receiving beam.

[0223] The transmitting and receiving unit 220 (transmitting processing unit 2211) may, for example, perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control) on the data and control information obtained from the control unit 210, and generate the bit string to be transmitted.

[0224] The transmitting and receiving unit 220 (transmitting processing unit 2211) can also perform transmission processing such as channel coding (which may also include error correction coding), modulation, mapping, filter processing, DFT processing (as needed), IFFT processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output the baseband signal.

[0225] Furthermore, the application of DFT processing can be based on the transform precoding settings. For a specific channel (e.g., PUSCH), if transform precoding is active (enabled), the transmit / receive unit 220 (transmit processing unit 2211) can perform DFT processing as described above for transmitting the channel using the DFT-s-OFDM waveform. Otherwise, the transmit / receive unit 220 (transmit processing unit 2211) can perform the aforementioned transmit processing without performing DFT processing.

[0226] The transmitting and receiving unit 220 (RF unit 222) can also perform modulation, filtering, amplification, etc. on the baseband signal to the wireless frequency band, and transmit the wireless frequency band signal through the transmitting and receiving antenna 230.

[0227] On the other hand, the transmitting and receiving unit 220 (RF unit 222) can also amplify, filter, demodulate baseband signals, etc., for the wireless frequency band signals received by the transmitting and receiving antenna 230.

[0228] The transmitting and receiving unit 220 (receiving and processing unit 2212) can also perform receiving and processing on the acquired baseband signal, such as analog-to-digital conversion, FFT processing, IDFT processing (as needed), filter processing, demapping, demodulation, decoding (which may also include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing, to obtain user data.

[0229] The transmitting / receiving 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 received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results can also be output to the control unit 210.

[0230] In addition, the transmitting unit and receiving unit of the user terminal 20 in this disclosure can also be configured by at least one transmitting / receiving unit 220 and transmitting / receiving antenna 230.

[0231] Additionally, the transmitting and receiving unit 220 receives specific information transmitted via at least one of the broadcast and multicast methods. Furthermore, the transmitting and receiving unit 220 may also transmit retransmission control information for specific information transmitted via at least one of the broadcast and multicast methods.

[0232] The control unit 210 may also determine whether retransmission control information for a specific piece of information is required based on at least one of the information transmitted from the network and the conditions applied in the transmission of that specific information. For example, the control unit 210 may also determine whether retransmission control information for a specific piece of information is required based on at least one of the application of repeated transmission of that specific information, the MCS applied in that specific information, and the coding rate applied in that specific information. Furthermore, the control unit 210 may be designed such that the process number used in retransmission control for that specific information and the process number used in retransmission control for information transmitted via unicast are both commonly set. Alternatively, the control unit 210 may be designed such that the process number used in retransmission control for that specific information and the process number used in retransmission control for information transmitted via unicast are set separately.

[0233] The control unit 210 can also determine the transmission timing of retransmission control information for specific information based on predefined values ​​and at least one piece of information transmitted from the network. Furthermore, the control unit 210 can select a specific transmission timing based on information related to a candidate set of transmission timings for retransmission control information for specific information and downlink control information commonly transmitted to a specific user terminal. Additionally, the control unit 210 can determine the transmission timing of retransmission control information for specific information based on a first transmission timing parameter notified via higher-layer signaling and a second transmission timing parameter notified via downlink control information. Furthermore, the control unit 210 can determine the resources used in transmitting retransmission control information for specific information based on a first resource parameter notified via higher-layer signaling and a second resource parameter specified using at least one of higher-layer signaling and downlink control information. Additionally, the control unit 210 can select specific resources based on a candidate set of resources used in transmitting retransmission control information for specific information and downlink control information commonly transmitted to a specific user terminal.

[0234] The control unit 210 can also determine the uplink channel transmission power used in transmitting retransmission control information for specific information based on transmission power parameters separately notified to each user terminal. Furthermore, the control unit 210 can also be conceived as having at least one transmission power parameter value and the transmission timing of the retransmission control information separately set for each user terminal. Additionally, the control unit 210 can also determine the transmission power based on a first transmission power parameter notified via higher-layer signaling and a second transmission power parameter specified using at least one of the higher-layer signaling and downlink control information. Furthermore, the control unit 210 can also determine the transmission power based on a transmission power control command contained in downlink control information that is different from the downlink control information scheduling the specific information.

[0235] The control unit 210 can also utilize resources commonly configured among multiple user terminals to control the reporting of retransmission control information for specific information. Furthermore, the control unit 210 can also control the reporting of only ACK and NACK as retransmission control information. Additionally, when the retransmission of specific information is sent via broadcast or multicast, the control unit 210 can determine whether the retransmitted information has been received based on the reception result of the specific information. Furthermore, the control unit 210 can also utilize resources separately configured among user terminals to control the reporting of retransmission control information for specific information. Moreover, the control unit 210 can also be designed to allow the retransmission of specific information to be sent via unicast.

[0236] (Hardware Structure)

[0237] Furthermore, the block diagrams used in the description of the above embodiments illustrate functional units. These functional blocks (structural units) are implemented through any combination of at least one of hardware and software. Moreover, the implementation method of each functional block is not particularly limited. That is, each functional block can be implemented using a single device that is physically or logically combined, or it can be implemented by directly or indirectly (e.g., using wired, wireless, etc.) connecting two or more physically or logically separate devices. A functional block can also be implemented by combining one or more of the aforementioned devices with software.

[0238] Here, the functions include judgment, decision, determination, calculation, calculation, processing, export, investigation, search, confirmation, receiving, sending, output, access, resolution, selection, choosing, establishing, comparison, assumption, expectation, regard as, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assigning, but are not limited to these. For example, a functional block (structural unit) that implements the sending function can also be called a transmitting unit, transmitter, etc. As described above, the implementation method is not particularly limited.

[0239] For example, in one embodiment of this disclosure, the base station, user terminal, etc., can also function as a computer for processing the wireless communication method of this disclosure. Figure 11This diagram illustrates an example of the hardware structure of a base station and a user terminal according to one embodiment. The base station 10 and the user terminal 20 described above can also be physically configured as a computer device including a processor 1001, a memory 1002, a storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0240] Furthermore, in this disclosure, terms such as apparatus, circuit, device, section, and unit are interchangeable. The hardware structure of base station 10 and user terminal 20 can be configured to include one or more of the apparatuses shown in the figures, or it can be configured not to include any of the apparatuses.

[0241] For example, only one processor 1001 is shown, but there can be multiple processors. Furthermore, processing can be performed by one processor, or simultaneously, sequentially, or by two or more processors using other methods. Additionally, processor 1001 can be implemented using more than one chip.

[0242] The functions of the base station 10 and the user terminal 20 are implemented, for example, by reading specific software (programs) into hardware such as the processor 1001 and the memory 1002, so that the processor 1001 performs calculations and controls communication via the communication device 1004, or controls at least one of reading out and writing data in the memory 1002 and the storage device 1003.

[0243] The processor 1001, for example, enables the operating system to operate and control the computer as a whole. The processor 1001 may also be configured as a central processing unit (CPU) that includes interfaces with peripheral devices, control devices, arithmetic devices, registers, etc. For example, at least a portion of the control unit 110 (210), the transmit / receive unit 120 (220), etc., described above may also be implemented by the processor 1001.

[0244] Furthermore, the processor 1001 reads programs (program code), software modules, data, etc., from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and performs various processes accordingly. As a program, a program that causes the computer to perform at least a portion of the operations described in the above embodiments can be used. For example, the control unit 110 (210) can also be implemented by a control program stored in the memory 1002 and operating in the processor 1001; similar implementations can be made for other functional blocks.

[0245] The memory 1002 may also be a computer-readable recording medium, such as being composed of at least one of read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), or other suitable storage media. The memory 1002 may also be referred to as a register, cache, main memory (main storage device), etc. The memory 1002 is capable of storing executable programs (program code), software modules, etc., for implementing the wireless communication method according to one embodiment of the present disclosure.

[0246] Storage 1003 may also be a computer-readable recording medium, such as at least one of a flexible disc, floppy disk, optical disk (e.g., compact disc ROM, CD-ROM), digital multifunction disk, Blu-ray disc, removable disk, hard disk, smart card, flash memory device (e.g., card, stick, key drive), magnetic stripe, database, server, or other suitable storage media. Storage 1003 may also be referred to as an auxiliary storage device.

[0247] The communication device 1004 is hardware (transmitting and receiving device) used for communication between computers via at least one of a wired network and a wireless network. It is also referred to as a network device, network controller, network interface card (NIC), communication module, etc. To implement at least one of, for example, Frequency Division Duplex (FDD) and Time Division Duplex (TDD), the communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. For example, the aforementioned transmit / receive unit 120 (220) and transmit / receive antenna 130 (230) may also be implemented by the communication device 1004. The transmit / receive unit 120 (220) may also be physically or logically separated from the receive unit 120a (220a) and the receiver unit 120b (220b).

[0248] Input device 1005 is an input device that accepts input from external sources (e.g., keyboard, mouse, microphone, switch, button, sensor, etc.). Output device 1006 is an output device that performs output to external sources (e.g., display, speaker, light-emitting diode (LED) lamp, etc.). Alternatively, input device 1005 and output device 1006 can also be an integrated structure (e.g., touch panel).

[0249] Furthermore, the processor 1001, memory 1002, and other devices are connected via a bus 1007 for communicating information. The bus 1007 can be a single bus or different buses can be used between the devices.

[0250] Furthermore, the base station 10 and the user terminal 20 can also be configured with hardware including a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field-programmable gate array (FPGA), etc., and can also use this hardware to implement part or all of the functional blocks. For example, the processor 1001 can also be installed using at least one of these hardware components.

[0251] (Modified Example)

[0252] Furthermore, the terms described in this disclosure and those necessary for understanding this disclosure may be replaced with terms that have the same or similar meanings. For example, channel, symbol, and signal (signal or signaling) may be used interchangeably. Additionally, a signal may also be a message. A reference signal may also be abbreviated as RS, and may be referred to as pilot, pilot signal, etc., depending on the applied standard. Furthermore, a component carrier (CC) may also be referred to as cell, frequency carrier, carrier frequency, etc.

[0253] A radio frame can also be composed of one or more periods (frames) in the time domain. Each period (frame) that constitutes the radio frame can also be called a subframe. Furthermore, a subframe can also be composed of one or more time slots in the time domain. A subframe can also be a fixed time length (e.g., 1 ms) independent of the parameter set (numerology).

[0254] Here, the parameter set can also refer to communication parameters applied in at least one of the transmission and reception of a signal or channel. For example, the parameter set can also represent at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering processing performed by the transmitter and receiver in the frequency domain, and specific windowing processing performed by the transmitter and receiver in the time domain.

[0255] In the time domain, a time slot can also be composed of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.). Furthermore, a time slot can also be a time unit based on a set of parameters.

[0256] A time slot can also contain multiple mini-time slots. Each mini-time slot can also consist of one or more symbols in the time domain. Furthermore, a mini-time slot can also be called a sub-time slot. A mini-time slot can also consist of fewer symbols than a time slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-time slot can also be called PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using mini-time slots can also be called PDSCH (PUSCH) mapping type B.

[0257] Radio frames, subframes, time slots, mini-time slots, and symbols all represent time units for transmitting signals. Radio frames, subframes, time slots, mini-time slots, and symbols can also use their respective other names. Furthermore, the time units such as frames, subframes, time slots, mini-time slots, and symbols used in this disclosure can be used interchangeably.

[0258] For example, a subframe can also be called a TTI, multiple consecutive subframes can also be called a TTI, a time slot or a mini-time slot can also be called a TTI. That is to say, at least one of the subframe and TTI can be a subframe in the existing LTE (1ms), a period shorter than 1ms (e.g., 1-13 symbols), or a period longer than 1ms. In addition, the unit representing TTI may not be called a subframe, but a time slot, mini-time slot, etc.

[0259] Here, TTI refers, for example, to the smallest unit of time for scheduling in wireless communication. For instance, in an LTE system, the base station schedules radio resources (frequency bandwidth, transmit power, etc., available to each user terminal) in TTI units. However, the definition of TTI is not limited to this.

[0260] TTI can also be a unit of time for transmitting channel-coded data packets (transmission blocks), code blocks, codewords, etc., and can also be a unit of processing such as scheduling and link adaptation. In addition, when a TTI is given, the actual time interval (e.g., the number of symbols) mapped to transmission blocks, code blocks, codewords, etc. can be shorter than the TTI.

[0261] Furthermore, when a time slot or a mini-time slot is referred to as a TTI, more than one TTI (i.e., more than one time slot or more than one mini-time slot) can also serve as the minimum time unit for scheduling. In addition, the number of time slots (mini-time slots) constituting the minimum time unit of the schedule can also be controlled.

[0262] A Time Interval (TTI) with a duration 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 a normal TTI can also be referred to as a shortened TTI, a short TTI, a partial TTI (partial or fractional TTI), a shortened subframe, a short subframe, a mini time slot, a sub-time slot, a time slot, etc.

[0263] In addition, long TTIs (e.g., normal TTIs, subframes, etc.) can be replaced with TTIs with a duration of more than 1 ms, and short TTIs (e.g., shortened TTIs, etc.) can be replaced with TTIs with a duration of less than long TTIs but more than 1 ms.

[0264] A resource block (RB) is a unit of resource allocation in the time and frequency domains. In the frequency domain, it can also contain one or more consecutive subcarriers. The number of subcarriers in an RB can be the same regardless of the parameter set, for example, it can be 12. The number of subcarriers in an RB can also be determined based on the parameter set.

[0265] Furthermore, an RB can contain one or more symbols in the time domain, and can also be a time slot, a mini-time slot, a subframe, or the length of a TTI. A TTI, a subframe, etc., can also be composed of one or more resource blocks.

[0266] In addition, one or more RBs can also be referred to as Physical Resource Blocks (PRBs), Sub-Carrier Groups (SCGs), Resource Element Groups (REGs), PRB pairs, RB pairs, etc.

[0267] Furthermore, a resource block can also consist of one or more resource elements (REs). For example, an RE can also be a radio resource area consisting of a subcarrier and a symbol.

[0268] The Bandwidth Part (BWP) (also referred to as partial bandwidth, etc.) can also represent a subset of consecutive common resource blocks (RBs) used for a certain parameter set in a certain carrier. Here, common RBs can also be determined by the index of RBs based on the common reference point of the carrier. PRBs can also be defined in a BWP and appended with numbers within that BWP.

[0269] A BWP can also include a UL BWP (BWP used by UL) and a DL BWP (BWP used by DL). For a UE, one or more BWPs can be set within a single carrier.

[0270] At least one of the configured BWPs can be active, and the UE may not intend to transmit or receive specific signals / channels outside of the active BWPs. Furthermore, terms such as "cell" and "carrier" in this disclosure can be replaced with "BWP".

[0271] Furthermore, the structures described above, such as radio frames, subframes, time slots, mini-time slots, and symbols, are merely illustrative. For example, the number of subframes contained in a radio frame, the number of time slots in each subframe or radio frame, the number of mini-time slots contained within a time slot, the number of symbols and RBs contained in a time slot or mini-time slot, the number of subcarriers contained in an RB, and the number of symbols in a TTI, symbol length, and cyclic prefix (CP) length can be varied in many ways.

[0272] Furthermore, the information, parameters, etc., described in this disclosure can be represented by absolute values, relative values ​​with respect to a specific value, or other corresponding information. For example, wireless resources can also be indicated by a specific index.

[0273] In this disclosure, the names used for parameters, etc., are not limiting names in any respect. Furthermore, the mathematical expressions, etc., using these parameters may differ from those explicitly disclosed in this disclosure. Various channels (PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name; therefore, the various names assigned to these various channels and information elements are not limiting names in any respect.

[0274] The information, signals, etc., described in this disclosure can also be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc., which may be mentioned throughout the above description, can also be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0275] Furthermore, information and signals can be output in at least one of the following directions: from higher layers (upper level) to lower layers (lower level), and from lower layers to higher layers. Information and signals can also be input and output via multiple network nodes.

[0276] Input and output information and signals can be stored in a specific location (such as memory) or managed using management tables. Input and output information and signals can be overwritten, updated, or appended. Output information and signals can also be deleted. Input information and signals can also be sent to other devices.

[0277] The notification of information is not limited to the methods / implementations described in this disclosure, and may also be carried out by other methods. For example, the notification of information in this disclosure may also be implemented through physical layer signaling (e.g., downlink control information (DCI), uplink control information (UCI), etc.), 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 combinations thereof.

[0278] In addition, physical layer signaling can also be referred to as Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signals), L1 control information (L1 control signals), etc. Furthermore, RRC signaling can also be referred to as RRC messages, such as RRC connection setup messages, RRC connection reconfiguration messages, etc. Additionally, MAC signaling can also be notified using, for example, the MAC control element (CE).

[0279] Furthermore, notification of specific information (e.g., a notification that “is X”) is not limited to explicit notification, but can also be implicit (e.g., by not providing that specific information, or by providing other information).

[0280] The determination can be made by a value represented by a single bit (0 or 1), by a true or false value (boolean), or by a numerical comparison (e.g., a comparison with a specific value).

[0281] Whether it is called software, firmware, middleware, microcode, hardware description language, or any other name, software should be broadly interpreted as instructions, instruction sets, code, code segments, program code, program, subprogram, software module, application, software application, software package, routine, subroutine, object, executable file, execution thread, process, function, etc.

[0282] Furthermore, software, instructions, and information 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 within the definition of a transmission medium.

[0283] The terms “system” and “network” as used in this disclosure are used interchangeably. “Network” may also mean devices included in a network (e.g., base stations).

[0284] In this disclosure, the terms "precoding", "precoder", "weight (precoding weight)", "quasi-co-location (QCL)", "transmission configuration indication state (TCI state)", "spatial relation", "spatial domain filter", "transmit power", "phase rotation", "antenna port", "antenna port group", "layer", "number of layers", "rank", "resource", "resource set", "resource group", "beam", "beamwidth", "beam angle", "antenna", "antenna element", and "panel" are used interchangeably.

[0285] In this disclosure, the terms "Base Station (BS)", "Wireless Base Station", "Fixed Station", "NodeB", "eNB (eNodeB)", "gNB (gNodeB)", "Access Point", "Transmission Point (TP)", "Reception Point (RP)", "Transmission / Reception Point (TRP)", "Panel", "Cell", "Sector", "Cell Group", "Carrier", and "Component Carrier" are used interchangeably. There are also instances where the terms macrocell, small cell, femtocell, and picocell are used to refer to a base station.

[0286] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, its coverage area can be divided into several smaller areas, each of which can provide communication services through a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). Terms such as "cell" or "sector" refer to a portion or all of the coverage area of ​​at least one of the base station and base station subsystem providing communication services within that coverage area.

[0287] In this disclosure, the terms “Mobile Station (MS)”, “user terminal”, “user equipment (UE)”, and “terminal” are used interchangeably.

[0288] In some cases, a mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, hand set, user agent, mobile client, client, or several other appropriate terms.

[0289] 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 also be a device mounted on a mobile body, the mobile body itself, etc. This mobile body can be a means of transportation (e.g., a vehicle, an airplane, etc.), a mobile body moving in an unmanned manner (e.g., a drone, an autonomous vehicle, etc.), or a robot (humanized or unmanned). Furthermore, at least one of the base station and the mobile station also includes devices that do 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.

[0290] Furthermore, the base station in this disclosure can also be replaced by a user terminal. For example, various methods / implementations of this disclosure can also be applied to a structure where the communication between the base station and the user terminal is replaced by communication between multiple user terminals (e.g., it can also be called device-to-device (D2D) or vehicle-to-everything (V2X)). In this case, it can also be configured such that the user terminal 20 has the functions of the base station 10 described above. In addition, expressions such as "uplink" and "downlink" can also be replaced with expressions corresponding to inter-terminal communication (e.g., "side"). For example, uplink channel, downlink channel, etc. can also be replaced with side channel.

[0291] Similarly, the user terminal in this disclosure can also be replaced by a base station. In this case, it can also be configured such that the base station 10 has the functions of the user terminal 20 described above.

[0292] In this disclosure, actions purported to be performed by the base station are sometimes also performed by its upper node, depending on the circumstances. Clearly, in a network comprising one or more network nodes having a base station, various operations performed for communication with a terminal can be performed by the base station, one or more network nodes other than the base station (e.g., considering a Mobility Management Entity (MME), a Serving-Gateway (S-GW), etc., but not limited to these), or combinations thereof.

[0293] The various methods / implementations described in this disclosure can be used individually, in combination, or switched as needed during execution. Furthermore, the processing procedures, sequences, flowcharts, etc., of the various methods / implementations described in this disclosure can be rearranged as long as they do not contradict each other. For example, with respect to the methods described in this disclosure, the illustrated order is used to indicate various steps, but the order in which they are indicated is not limited.

[0294] The various methods / implementations described in this 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), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Futuregeneration radio access (FX), Global System for Mobile Communications (GSM), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE The terms include 802.20, Ultra-Wideband (UWB), Bluetooth (registered trademark), systems utilizing other appropriate wireless communication methods, and next-generation systems derived from them. Furthermore, multiple systems can be combined (e.g., LTE or LTE-A, combinations with 5G, etc.) for application.

[0295] As used in this disclosure, the word "based on" does not mean "based on only" unless otherwise specified. In other words, the word "based on" means both "based on only" and "based on at least".

[0296] Any reference to an element using the terms "first," "second," etc., as used in this disclosure does not comprehensively limit the quantity or order of these elements. These terms may be used in this disclosure as a convenient method of distinguishing between two or more elements. Therefore, references to the first and second elements do not imply that only two elements are permitted, or that the first element must take precedence over the second element in some form.

[0297] The term "determining" as used in this disclosure can encompass a variety of actions in some cases. For example, "determining" can also refer to judging, calculating, computing, processing, deriving, investigating, looking up (e.g., searching in a table, database, or other data structure), and ascertaining.

[0298] In addition, "judgment (decision)" can also refer to receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, accessing (e.g., accessing data in memory), etc., as situations where "judgment (decision)" is performed.

[0299] Furthermore, "judgment (decision)" can also refer to situations where resolving, selecting, choosing, establishing, or comparing are considered as making a "judgment (decision)". In other words, "judgment (decision)" can also refer to certain actions as situations where a "judgment (decision)" is made.

[0300] In addition, "judgment (decision)" can also be replaced with "assuming", "expecting", "considering", etc.

[0301] The term "maximum transmit power" as used in this disclosure can refer to the maximum value of the transmit power, the nominal maximum transmit power (the nominal UE maximum transmit power), or the rated maximum transmit power (the rated UE maximum transmit power).

[0302] As used in this disclosure, the terms "connected," "coupled," or all variations thereof, mean any direct or indirect connection or combination between two or more elements, and can include cases where there is one or more intermediate elements between two mutually "connected" or "coupled" elements. The combination or connection between elements can be physical, logical, or a combination of these. For example, "connected" can also be replaced with "access."

[0303] In this disclosure, when connecting two elements, it is possible to consider using more than one wire, cable, printed electrical connection, etc., and as several non-limiting and non-inclusive examples, using electromagnetic energy with wavelengths in the wireless frequency domain, microwave region, light (both visible and invisible) region, to "connect" or "combine" them with each other.

[0304] In this disclosure, the term "A is different from B" can also mean "A and B are different from each other". Additionally, the term can also mean "A and B are different from C respectively". Terms such as "separate" and "combined" can also be interpreted as "different".

[0305] In this disclosure, the terms “include,” “including,” and variations thereof, as well as the term “comprising,” mean inclusiveness. Furthermore, the term “or” as used in this disclosure does not mean XOR.

[0306] In this disclosure, for example, in cases where articles are added through translation, such as a, an, and the in English, the disclosure may also include cases where the noun following these articles is in a plural form.

[0307] The inventions disclosed herein have been described in detail above. However, it will be apparent to those skilled in the art that the inventions are not limited to the embodiments described herein. The inventions disclosed herein can be implemented as modifications and variations without departing from the spirit and scope of the invention as defined by the claims. Therefore, the description in this disclosure is for illustrative purposes only and is not intended to limit the inventions disclosed herein in any way.

[0308] This application is based on Japanese Patent Application No. 2019-094078, filed on May 17, 2019. This application contains its entire contents.

Claims

1. A terminal, characterized in that, have: The receiving unit receives downlink control information (DCI) and the specific information that is scheduled to be sent by at least one of broadcast and multicast. as well as The control unit, based on the retransmission control-related information contained in the DCI, determines whether retransmission control information, i.e., HARQ-ACK, has been sent for the specific information. The control unit determines the transmission timing of the HARQ-ACK based on information specifying a particular transmission timing contained in the DCI, among multiple transmission timings of the HARQ-ACK that are notified via higher-layer signaling.

2. A wireless communication method, which is a wireless communication method for a terminal, characterized in that, have: The steps of receiving downlink control information (DCI) and said specific information that is sent by the scheduler via at least one of broadcast and multicast; Based on the information related to retransmission control contained in the DCI, determine whether there is a step to send retransmission control information, i.e., HARQ-ACK, for the specific information. as well as The step of determining the transmission timing of the HARQ-ACK based on information specifying a particular transmission timing contained in the DCI among multiple transmission timings of the HARQ-ACK notified via higher-level signaling.

3. A base station, characterized in that, have: The transmitting unit transmits downlink control information (DCI) and the specific information, which are scheduled to be transmitted by at least one of the broadcast and multicast methods. as well as The control unit, through the retransmission control-related information contained in the DCI, indicates whether or not HARQ-ACK retransmission control information for the specific information in the terminal should be sent. The control unit sets multiple transmission timings for the HARQ-ACK via higher-layer signaling, and instructs the terminal on the transmission timing of the HARQ-ACK by using information specifying a particular transmission timing contained in the DCI.

4. A system having a terminal and a base station, characterized in that, The terminal has: The receiving unit receives downlink control information (DCI) and the specific information that is scheduled to be sent by at least one of broadcast and multicast. as well as The control unit, based on the retransmission control-related information contained in the DCI, determines whether retransmission control information, i.e., HARQ-ACK, has been sent for the specific information. The control unit, among multiple transmission timings of the HARQ-ACK notified via higher-layer signaling, determines the transmission timing of the HARQ-ACK based on information specifying a particular transmission timing contained in the DCI. The base station has: a transmitting unit for transmitting the DCI and the specific information; as well as The control unit, using the retransmission control-related information contained in the DCI, instructs the terminal whether or not the HARQ-ACK has been sent. The control unit sets the multiple transmission timings through the higher-layer signaling, and instructs the terminal on the transmission timing of the HARQ-ACK through the information specifying the specific transmission timing contained in the DCI.

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