Terminal and communication method

Abstract

This terminal comprises: a reception unit which receives data and control information that triggers the retransmission of a hybrid automatic repeat request (HARQ) response corresponding to the data; a control unit which determines the HARQ response to be retransmitted, when the reception unit receives the control information; and a transmission unit which transmits the HARQ response to be retransmitted, wherein the control unit determines the response to be retransmitted, on the basis of at least a priority set for the HARQ response.

Description

[Technical Field]

[0001] The present invention relates to a terminal and a communication method in a wireless communication system. [Background technology]

[0002] The 3GPP (3rd Generation Partnership Project) is currently studying a wireless communication system called 5G or NR (New Radio) (hereinafter referred to as "NR") in order to achieve even larger system capacity, even faster data transmission speeds, and even lower latency in wireless sections. Various wireless technologies and network architectures are being studied for 5G to meet the requirements of achieving a throughput of 10 Gbps or more while keeping latency in wireless sections to 1 ms or less.

[0003] In addition, NR specifies downlink semi-persistent scheduling (SPS), in which PDSCH (Physical Downlink Shared Channel) resources are configured in advance in a terminal and activation / release is performed using DCI (Downlink Control Information), thereby enabling low-latency data reception (e.g., Non-Patent Documents 1 and 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.213 V16.3.0 (2020-09) [Non-patent document 2] 3GPP TS 38.331 V16.2.0 (2020-09) Summary of the Invention [Problem to be solved by the invention]

[0005] In NR, priorities are set for signals or channels, and communication is controlled based on the set priorities. For example, a PUCCH (Physical Uplink Control Channel) for transmitting a HARQ-ACK (Hybrid automatic repeat request Acknowledgement) corresponding to PDSCH reception may be dropped due to priority control. Also, a HARQ-ACK corresponding to a PDSCH by SPS may collide with a DL (Downlink) symbol or a flexible symbol, causing the HARQ-ACK to be dropped.

[0006] Therefore, a trigger for retransmitting HARQ-ACK feedback has been proposed. However, it is unclear how to handle the retransmission of HARQ-ACK.

[0007] The present invention has been made in view of the above points, and has as its object to enable a terminal to retransmit, to a base station, feedback information that has been dropped in response to reception of data. [Means for solving the problem]

[0008] According to the disclosed technology, a receiving unit that receives data and control information from a base station, the control information including a field that instructs retransmission of a hybrid automatic repeat request (HARQ) response corresponding to the data and a field that instructs the priority of the HARQ response, and that does not involve scheduling; a control unit that, when the receiving unit receives the control information, determines an HARQ response to be retransmitted based on the priority, a window size defined in advance in a specification, and an offset obtained by reinterpreting an existing field included in the control information; and a transmitting unit that transmits the HARQ response to be retransmitted to the base station. A terminal is provided. [Effects of the Invention]

[0009] The disclosed technique enables a terminal to retransmit dropped feedback information corresponding to received data to a base station. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. [Figure 2] 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. [Figure 3]FIG. 2 is a sequence diagram illustrating a basic operation of the wireless communication system according to the embodiment of the present invention. [Figure 4] FIG. 10 is a diagram illustrating an example of HARQ-ACK transmission in an embodiment of the present invention. [Figure 5] FIG. 2 is a diagram illustrating an example (1) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 6] FIG. 10 is a diagram illustrating an example (2) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating an example (3) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 8] FIG. 10 is a diagram illustrating an example (4) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 9] FIG. 10 is a diagram showing an example (5) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 10] FIG. 10 is a diagram illustrating an example (6) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing an example (7) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 12] FIG. 10 is a diagram showing an example (8) of an HARQ-ACK codebook according to an embodiment of the present invention. [Figure 13] 2 is a diagram illustrating an example of a functional configuration of a base station 10 according to an embodiment of the present invention. [Figure 14] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal 20 according to the embodiment of the present invention. [Figure 15] 2 is a diagram illustrating an example of a hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0012] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are used as appropriate. However, the existing technologies are, for example, but not limited to, the existing LTE. Furthermore, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems subsequent to LTE-Advanced (e.g., NR) unless otherwise specified.

[0013] Furthermore, in the embodiments of the present invention described below, terms used in existing LTE, such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel), are used. This is for convenience of description, and similar signals, functions, etc. may be referred to by other names. Furthermore, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even signals used in NR are not necessarily designated as "NR-".

[0014] Furthermore, in the embodiments of the present invention, the duplex method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or other methods (for example, Flexible Duplex, etc.).

[0015] Furthermore, in the embodiments of the present invention, when radio parameters and the like are "configured," it may mean that predetermined values ​​are pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are set.

[0016] Fig. 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. As shown in Fig. 1, the wireless communication system according to the embodiment of the present invention includes a base station 10 and a terminal 20. Although Fig. 1 shows one base station 10 and one terminal 20, this is an example, and there may be a plurality of each.

[0017] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of a wireless signal are defined in the time domain and the frequency domain, and the time domain may be defined by the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. Furthermore, a TTI (Transmission Time Interval) in the time domain may be a slot or a subslot, or a TTI may be a subframe.

[0018] Base station 10 is capable of performing carrier aggregation, which aggregates multiple cells (multiple CCs (component carriers)) to communicate with terminal 20. In carrier aggregation, one primary cell (PCell) and one or more secondary cells (SCells) are used.

[0019] The base station 10 transmits a synchronization signal, system information, and the like to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is transmitted, for example, on the NR-PBCH or PDSCH, and is also called broadcast information. As shown in FIG. 1 , the base station 10 transmits control signals or data to the terminal 20 on the DL (Downlink) and receives control signals or data from the terminal 20 on the UL (Uplink). Note that, here, what is transmitted on a control channel such as the PUCCH or PDCCH is called a control signal, and what is transmitted on a shared channel such as the PUSCH or PDSCH is called data, but these names are merely examples.

[0020] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, or an M2M (Machine-to-Machine) communication module. As shown in Fig. 1, the terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. The terminal 20 may be referred to as a UE, and the base station 10 may be referred to as a gNB.

[0021] Terminal 20 can perform carrier aggregation, which aggregates multiple cells (multiple CCs) to communicate with base station 10. In carrier aggregation, one primary cell and one or more secondary cells are used. Also, a PUCCH-SCell having a PUCCH may be used.

[0022] Fig. 2 shows an example of the configuration of a wireless communication system when DC (Dual connectivity) is implemented. As shown in Fig. 2, a base station 10A serving as an MN (Master Node) and a base station 10B serving as an SN (Secondary Node) are provided. The base station 10A and the base station 10B are each connected to a core network. The terminal 20 can communicate with both the base station 10A and the base station 10B.

[0023] A cell group provided by base station 10A, which is an MN, is called an MCG (Master Cell Group), and a cell group provided by base station 10B, which is an SN, is called an SCG (Secondary Cell Group). In addition, in a DC, an MCG is composed of one PCell and one or more SCells, and an SCG is composed of one PSCell (Primary SCG Cell) and one or more SCells.

[0024] The processing operations in this embodiment may be executed in the system configuration shown in FIG. 1, in the system configuration shown in FIG. 2, or in any other system configuration.

[0025] An example of a basic operation of the communication system according to the embodiment of the present invention will be described with reference to Fig. 3. This operation is basically common to the examples described later.

[0026] In S101, by RRC signaling, base station 10 transmits downlink SPS configuration information, PUCCH resource configuration information, slot format configuration information, etc. to terminal 20, and terminal 20 receives this configuration information. Note that since this embodiment targets downlink SPS, hereinafter, "SPS" means downlink SPS.

[0027] The slot format configuration information is, for example, tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated, and this configuration information determines whether the TDD configuration for each symbol in each of one or more slots is DL, UL, or flexible. Hereinafter, this configuration information will be referred to as semi-static TDD configuration information. Flexible may also be abbreviated as F. Terminal 20 basically determines DL / UL / F for each symbol in each slot according to the semi-static TDD configuration information.

[0028] In addition, multiple slot format candidates may be notified as the setting information in S101 to enable dynamic switching of the slot format. This setting information is, for example, SlotFormatCombinationsPerCell. Since this information is information consisting of slot format (SF) IDs, this information will be referred to as SFI setting information hereinafter.

[0029] In S102, terminal 20 receives DCI activating the SPS configuration from base station 10, and in S103 receives data in the PDSCH resource according to the SPS configuration. In S104, terminal 20 transmits an SPS HARQ-ACK to base station 10 in the PUCCH resource (or PUSCH resource if there is UL scheduling) of the slot at the time position specified by the DCI. Hereinafter, a HARQ-ACK corresponding to data reception in one or more PDSCH resources according to the SPS configuration will be referred to as an "SPS HARQ-ACK." Hereinafter, the SPS HARQ-ACK may also be referred to as an HARQ-ACK. The HARQ-ACK may also be referred to as HARQ information, a HARQ response, feedback information, etc.

[0030] The terminal 20 may receive DCI from the base station 10 at S102 or before or after that, which dynamically specifies a slot format. This DCI is control information that specifies the ID to actually use from among the IDs of multiple slot formats set by the SFI setting information. When a slot format is specified by this DCI, the terminal 20 determines DL / UL / F of each symbol in each slot according to the slot format instead of the semi-static TDD setting information. This DCI information is called dynamic SFI specification information (or dynamic SFI, or SFI).

[0031] As described above, each time terminal 20 receives data via SPS, the activation DCI specifies the time position (slot) at which to transmit HARQ-ACK using the PUCCH resource.

[0032] However, particularly when multiple short-period SPSs are configured in terminal 20, depending on the TDD DL / UL configuration in the slot at the specified time position (configuration using semi-static TDD configuration information or dynamic SFI specification information), the symbol position at which the PUCCH resource is configured may collide with the DL symbol or F symbol, and the HARQ-ACK may be dropped.

[0033] Furthermore, prioritization within terminal 20 is assumed as a case in which other HARQ-ACKs are dropped. For example, if two UL transmissions with different priorities overlap, the UL transmission with the lower priority is dropped. Prioritization between terminals 20 is also assumed. For example, when HARQ-ACKs are multiplexed in a PUSCH, if PUSCH transmission is canceled by terminal 20 receiving DCI format 2_4, the HARQ-ACK transmitted on the PUSCH is dropped.

[0034] One-shot HARQ-ACK feedback is a method for retransmitting the dropped HARQ-ACK. One-shot HARQ-ACK feedback uses a codebook that includes HARQ-ACKs corresponding to all HARQ processes in all serving cells in a PUCCH group, resulting in a large payload size.

[0035] Therefore, in the embodiment of the present invention, the following processes A) to D) will be clarified as processes related to the method of retransmitting HARQ-ACK.

[0036] A) Determine the format of the DCI that triggers the retransmission of the HARQ-ACK. B) Determine which HARQ-ACK bits to retransmit. C) Determine the resources to be used for retransmitting the HARQ-ACK. D) Determine the HARQ-ACK codebook to be used for retransmitting the HARQ-ACK.

[0037] An existing DCI format may be used as the format of the DCI that triggers the retransmission of the HARQ-ACK in A) above.

[0038] An existing UE-specific DCI with or without PUSCH or PDSCH scheduling may be used. For example, the existing UE-specific DCI may be DCI0_0, DCI0_1, DCI1_0, DCI1_1, or DCI1_2. When indicating that HARQ-ACK retransmission is triggered by DCI1_1, the higher layer parameter pdsch-HARQ-ACK-OneShotFeedback-r16 may or may not be indicated. If pdsch-HARQ-ACK-OneShotFeedback-r16 is indicated, the field requesting DCI retransmission may be set to 0 or 1.

[0039] Furthermore, an existing group common DCI (GC (Group Common)-DCI) format with or without notification of conventional functions may be used. For example, the existing group common DCI format may be DCI2_0, DCI2_1, DCI2_2, DCI2_3, DCI2_4, etc.

[0040] The DCI that triggers the retransmission of the HARQ-ACK and / or schedules the data may be identified as 1) or 2) shown below.

[0041] 1) When a DCI that triggers a HARQ-ACK is not used simultaneously with a conventional function (e.g., data scheduling, SPS release, etc. in a UE-specific DCI, or Slot format indicator (SFI), Transmit power control (TPC), Pre-emption indication (PI), Cancellation indication (CI), etc. in a GC-DCI), a new bit field or an existing DCI field may be used to identify whether the DCI indicates a HARQ-ACK retransmission or a conventional function. For example, if the Frequency Domain Resource Allocation (FDRA) field is all 0s or all 1s, the DCI may trigger a HARQ-ACK retransmission instead of scheduling data. Also, when it is necessary to indicate which HARQ-ACK to retransmit, an existing DCI field may be reinterpreted to indicate information related to the HARQ-ACK retransmission.

[0042] 2) When a DCI that triggers a HARQ-ACK is used simultaneously with a conventional function (e.g., data scheduling, SPS release, etc. in a UE-specific DCI, or SFI, TPC, PI, CI, etc. in a GC-DCI), whether the DCI triggers a retransmission of a HARQ-ACK may be identified by a new bit field or an existing DCI field. For example, if the FDRA field is all 0s or all 1s, the DCI may trigger a retransmission of a HARQ-ACK. Also, when it is necessary to indicate which HARQ-ACK to retransmit, the newly added DCI field may be reinterpreted to indicate information related to the HARQ-ACK retransmission.

[0043] As the format of the DCI that triggers the retransmission of the HARQ-ACK in A) above, a new UE-specific DCI format or a GC-DCI format may be used.

[0044] When it is necessary to notify which HARQ-ACK to retransmit, a newly added DCI field may be defined to notify information related to HARQ-ACK retransmission.

[0045] As a method of determining which HARQ-ACK bit to retransmit (B) above, it may be possible to determine which priority level is set for the HARQ-ACK to be transmitted.

[0046] Of the priorities set for the HARQ-ACK (for example, HP (High priority) and LP (Low priority)), only the HARQ-ACK to which one priority is set may be retransmitted. The priority of the PUCCH carrying the retransmitted HARQ-ACK may be the same as the priority of the HARQ-ACK transmission in prioritization within terminal 20. For example, the priority of the retransmitted HARQ-ACK may be determined as shown in 1)-6) below.

[0047] 1) The priority of the retransmitted HARQ-ACK may be indicated by a priority indicator in the DCI field. For example, when the retransmission of the HARQ-ACK is triggered by DCI scheduling a PDSCH or a PUSCH, the scheduled PDSCH or PUSCH and the retransmitted HARQ-ACK may have the same priority.

[0048] 2) A new DCI field may indicate the priority of the retransmitted HARQ-ACK.

[0049] 3) The priority of the retransmitted HARQ-ACK may be indicated by the DCI format. For example, DCI format 1_1 may indicate the retransmission of the LP HARQ-ACK, and DCI format 1_2 may indicate the retransmission of the HP HARQ-ACK.

[0050] 4) LP HARQ-ACK may always be retransmitted.

[0051] 5) HP HARQ-ACK may always be retransmitted.

[0052] 6) The HARQ-ACK that was last dropped according to the rule described below may be implicitly notified as needing to be retransmitted with the same priority as the dropped HARQ-ACK.

[0053] As a method for determining which HARQ-ACK bit to retransmit (B) above, it may be determined to transmit an HARQ-ACK with both priorities (e.g., HP and LP) set. For example, the priorities of the HARQ-ACK to be retransmitted may be determined as shown in 1) and 2) below.

[0054] 1) LP HARQ-ACK and HP HARQ-ACK may always be retransmitted.

[0055] 2) A one-bit field in the DCI may indicate whether to retransmit a HARQ-ACK for which both priorities are set or a HARQ-ACK for which only one priority is set. For example, when the field is 1, it may indicate that a HARQ-ACK for which both priorities are set is to be retransmitted. For example, when the field is 0, it may indicate that a HARQ-ACK for which only one priority is set is to be retransmitted, and the priority indicator in the DCI may indicate which priority the HARQ-ACK for which priority is to be retransmitted. Also, when the field is 0, it may indicate that a HARQ-ACK for which only one priority is set is to be retransmitted, and a new DCI field may indicate which priority the HARQ-ACK for which priority is to be retransmitted. Also, when the field is 0, it may indicate that a HARQ-ACK for which only one priority is set is to be retransmitted, and the DCI format may indicate which priority the HARQ-ACK for which priority is to be retransmitted. For example, it may be indicated that a LP HARQ-ACK is to be retransmitted using DCI format 1_1, or that a HP HARQ-ACK is to be retransmitted using DCI format 1_2. Furthermore, when this field is 0, it may be indicated that a HARQ-ACK with one priority set will be retransmitted, or the LP HARQ-ACK may always be retransmitted. Furthermore, when this field is 0, it may be indicated that a HARQ-ACK with one priority set will be retransmitted, or the HP HARQ-ACK may always be retransmitted.

[0056] In the case where the priority indicator of the above DCI indicates which priority is set for the HARQ-ACK to be retransmitted, and in the case where a new DCI field indicates which priority is set for the HARQ-ACK to be retransmitted, the new DCI field may indicate whether to retransmit the HARQ-ACK with both priorities set or the HARQ-ACK with only one priority set.

[0057] When the above DCI format indicates which priority is set for the HARQ-ACK to be retransmitted, when the LP HARQ-ACK is always retransmitted, and when the HP HARQ-ACK is always retransmitted, a new DCI field may indicate whether to retransmit the HARQ-ACK with both priorities set or the HARQ-ACK with one priority set, or by reusing the priority indicator, it may indicate whether to retransmit the HARQ-ACK with both priorities set or the HARQ-ACK with one priority set.

[0058] As a method of determining which HARQ-ACK bit to retransmit in B), when it is determined to transmit an HARQ-ACK with both priorities (e.g., HP and LP) set, the HARQ-ACK may be separated and retransmitted using two HARQ-ACK codebooks. PUCCH resources (described later) are determined for the two HARQ-ACK codebooks, and the priorities set for the respective PUCCHs may be the same as those used in the multiplexing process within terminal 20.

[0059] Furthermore, when it is determined to transmit HARQ-ACKs with both priorities (e.g., HP and LP) set as the method of determining which HARQ-ACK bit to retransmit in the above B), one HARQ-ACK codebook may be used to combine and retransmit the HARQ-ACKs. When combining and retransmitting HARQ-ACKs, the granularity of K1 (i.e., slot or subslot), PUCCH resources, and priorities related to multiplexing processing in terminal 20 may be determined as shown in 1)-4) below. The K1 value indicates the offset from the data to the corresponding HARQ-ACK.

[0060] 1) The granularity of K1 may be based on the setting of the HP HARQ-ACK codebook. The priority for the multiplexing process in terminal 20 of the PUCCH resource for transmitting the HP HARQ-ACK may be HP.

[0061] 2) The granularity of K1 may be based on the setting of the LP HARQ-ACK codebook. The priority for multiplexing processing in terminal 20 of the PUCCH resource for transmitting the LP HARQ-ACK may be HP.

[0062] 3) The priority may be signaled using a new DCI field or by reusing the priority indicator. The granularity of K1 may be based on a HARQ-ACK codebook setting associated with the priority signaled by the new DCI field or the priority indicator. The priority set for the PUCCH for transmitting the HARQ-ACK may be signaled by the new DCI field or the priority indicator. The priority related to the multiplexing process in terminal 20 of the PUCCH resource for transmitting the HARQ-ACK may be signaled by the new DCI field or the priority indicator.

[0063] 4) The priority may be signaled by RRC configuration. The granularity of K1 may be based on a HARQ-ACK codebook configuration associated with the priority signaled by the RRC configuration. The priority set for the PUCCH for transmitting the HARQ-ACK may be signaled by RRC configuration. The priority related to the multiplexing process in terminal 20 of the PUCCH resource for transmitting the HARQ-ACK may be signaled by RRC configuration.

[0064] Furthermore, as a method for determining which HARQ-ACK bit to retransmit (B) above, the determination may be made as shown in the following options 1) to 7).

[0065] Option 1) All dropped HARQ-ACK bits corresponding to all configured HARQ-ACK processes in all serving cells may be retransmitted.

[0066] Option 2) Some or all of the HARQ-ACK bits in a certain window may be retransmitted. For example, window size M may be defined in units of the number of HARQ-ACKs. For example, window size M may be a window size that includes M most recent HARQ-ACKs (which may be only dropped HARQ-ACKs or may be all HARQ-ACKs) before offset N of the DCI that triggers retransmission. Alternatively, window size M may be determined such that the most recent HARQ-ACKs before offset N of the DCI that triggers retransmission are included in the window, and the N HARQ-ACKs reported from terminal 20 are from the last dropped HARQ-ACK in the window to the slot at which DCI reception starts. Alternatively, window size M may be determined such that there are N slots or N subslots from the last dropped HARQ-ACK in the window to the slot at which DCI reception starts.

[0067] Furthermore, the window size M may be defined in units of slots or sub-slots. For example, the window may be M slots or M sub-slots nearest to the triggering DCI. The start or end slot or sub-slot of the window may be determined by applying an offset of N slots or N sub-slots before the start of the triggering DCI slot. FIG. 4 is a diagram showing an example of HARQ-ACK transmission in an embodiment of the present invention. FIG. 4 shows an example of a window when M=2 and N=1. When retransmission is performed regardless of whether the HARQ-ACK was dropped or not, the HARQ-ACKs in sub-slots #2n+1, #2n+2, and #2n+3 are retransmitted. When only dropped HARQ-ACKs are retransmitted, the HARQ-ACKs in sub-slots #2n+1 and #2n+3 are retransmitted.

[0068] In the above option 2), M slots or sub-slots and N slots or sub-slots may be defined by the SCS of the PUCCH configured in the serving cell, or may be defined by the smallest SCS among the SCS of the PUCCH configured in the serving cell and the SCS of the triggering DCI, or may be defined by the information element referenceSubcarrierSpacing notified by the RRC configuration parameter tdd-UL-DL-ConfigurationCommon.

[0069] Option 3) HARQ-ACK bits corresponding to PDSCHs in a window configured for each serving cell (dropped HARQ-ACKs or all HARQ-ACKs) may be retransmitted. For example, window size M may be defined in units of the number of PDSCHs. For example, window size M may be a window size that includes M PDSCHs that are closest to offset N of DCI that triggers retransmission. Alternatively, window size M may be determined such that the closest PDSCHs that are closest to offset N of DCI that triggers retransmission are included in the window of the current serving cell, and N PDSCHs are included from the last PDSCH in the window to the slot at which DCI reception starts, or such that N slots are included from the last PDSCH in the window to the slot at which DCI reception starts.

[0070] Alternatively, the window size M may be defined in units of DL slots. For example, the window may be M slots closest to the triggering DCI. An offset of N slots before the start of the triggering DCI slot may be applied to determine the start or end slot of the window.

[0071] In the above option 3), M slots and N slots may be defined by the SCS of the PUCCH configured in the serving cell, or may be defined by the smallest SCS among the SCS of the serving cell, the SCS of the DCI that triggers retransmission, and / or the SCS of the PUCCH configured in the serving cell, or may be defined by the information element referenceSubcarrierSpacing notified by the RRC configuration parameter tdd-UL-DL-ConfigurationCommon.

[0072] Option 4) HARQ-ACK bits (dropped HARQ-ACKs or all HARQ-ACKs) corresponding to PDSCHs in a window commonly configured in all serving cells may be retransmitted. For example, window size M may be defined in units of the number of PDSCHs. For example, window size M may be a window size that includes M PDSCHs that are closest to offset N of DCI that triggers retransmission. Alternatively, window size M may be determined such that the closest PDSCH that is closest to offset N of DCI that triggers retransmission is included in the window of the current serving cell, and N PDSCHs are included from the last PDSCH in the window to the slot at which DCI reception starts, or such that N slots are included from the last PDSCH in the window to the slot at which DCI reception starts.

[0073] Alternatively, the window size M may be defined in units of DL slots. For example, the window may be M slots closest to the triggering DCI. An offset of N slots before the start of the triggering DCI slot may be applied to determine the start or end slot of the window.

[0074] In the above option 4), M slots and N slots may be defined by the smallest SCS among the SCSs of the PUCCHs configured in all PDSCH serving cells, or may be defined by the SCS of the triggering DCI and / or the SCS of the PUCCH configured in the serving cell, or the smallest SCS among the SCSs of the PDSCHs configured in all PDSCH serving cells, or may be defined by the information element referenceSubcarrierSpacing notified by the RRC configuration parameter tdd-UL-DL-ConfigurationCommon.

[0075] The window size M and offset N in the above options 2, 3 and 4 may be defined as follows:

[0076] The window size M and the offset N may be determined independently, may be predefined in the specification, or may be signaled by RRC configuration. The window size M and the offset N may be signaled by a new DCI field, or may reinterpret an existing DCI field that is not used. Alternatively, a set of values ​​may be defined in the specification or configured by RRC, and the DCI may signal one value from the set.

[0077] The window size M and offset N may be combined and signaled in a new DCI field, or may be signaled by reusing an existing DCI field, such as a Time Domain Resource Allocation (TDRA) field that is not used when no scheduling data is involved. For example, a table of the window size M and offset N may be configured in the RRC configuration or specifications, and M and N may be signaled by signaling a row index in the DCI. In the table, M and N may be arranged in separate columns. Also, in the table, M and N may be jointly coded into a single value (similar to S and L in SLIV).

[0078] Furthermore, in the above Option 3, if a serving cell-specific window is required, M and N to be notified for each serving cell may be determined in common. For example, M and N may be applied to all serving cells with a single notification, or common M and N may be defined or notified for each serving cell.

[0079] Option 5) HARQ-ACK bits (dropped HARQ-ACK or all HARQ-ACK) for PDSCH in a serving cell may be retransmitted. For example, HARQ-ACK bits for PDSCH in all serving cells may be retransmitted. Also, for example, the index of the serving cell that retransmits the HARQ-ACK bits for PDSCH may be defined by the standard or may be notified by RRC configuration.

[0080] Also, for example, the index of the serving cell to which the HARQ-ACK bit for the PDSCH is retransmitted may be signaled by reinterpreting a new DCI field or an unused existing DCI field. Each bit of the DCI field may correspond to one serving cell index, and the mapping between the bit and the cell index may be defined in a specification. That is, all serving cell indexes may be mapped. Alternatively, the mapping between the bit and the cell index may be signaled by RRC configuration. That is, RRC may configure a set of serving cell indexes to be mapped. Alternatively, the mapping between the bit and the serving cell index may be signaled by DCI. For example, the mapping between several sets of serving cells and each bit string of the DCI field may be configured by RRC configuration, or a set of serving cells to which another DCI field is mapped may be signaled. Also, for example, several sets of serving cells may be configured by RRC configuration, and the DCI field may signal one serving cell set. The index of the serving cell included in the set may be signaled for HARQ-ACK retransmission.

[0081] Option 6) The HARQ-ACK bit of the PDSCH corresponding to one HARQ process ID included in the HARQ process ID set may be retransmitted.

[0082] For example, HARQ-ACK bits corresponding to all HARQ process IDs configured in each serving cell may be retransmitted.Also, for example, HARQ-ACK bits determined commonly for HARQ process ID sets in all serving cells may be retransmitted.Also, for example, HARQ-ACK bits corresponding to HARQ process ID sets determined separately for each serving cell may be retransmitted.

[0083] The above commonly determined HARQ process ID set or the above separately determined HARQ process ID set may be determined as follows 1) to 3).

[0084] 1) May be determined by the specification.

[0085] 2) It may be notified by RRC configuration.

[0086] 3) A new DCI field or an unused existing DCI field may be notified by reinterpreting it. For example, each bit included in the DCI field may correspond to one HARQ process ID, and the mapping between the bits and the HARQ process IDs may be defined in a specification. For example, all configured HARQ process IDs may be mapped. Alternatively, a set of HARQ process IDs to be mapped may be configured by RRC configuration. Alternatively, the mapping between the bits and the HARQ process IDs may be signaled by the DCI. For example, the RRC configuration may map some sets of HARQ process IDs to the bit string of the DCI field, or may signal a set of HARQ process IDs to which another DCI field is mapped.

[0087] Option 7) The HARQ-ACK bit to be retransmitted may be determined by any combination of options 2-6 above.

[0088] For example, according to option 5 and option 6, a HARQ-ACK bit corresponding to the notified HARQ process ID of a certain serving cell may be retransmitted. For example, according to option 2 and option 5, a HARQ-ACK bit included in a window in a certain serving cell may be retransmitted. For example, according to option 3, option 4, and option 5, a HARQ-ACK bit corresponding to a PDSCH included in a window in a certain serving cell may be retransmitted. For example, according to option 2 and option 6, a HARQ-ACK bit corresponding to a PDSCH corresponding to a certain HARQ process ID included in the window may be retransmitted. For example, according to option 3, option 4, and option 6, a HARQ-ACK bit corresponding to a PDSCH included in a window in a certain serving cell may be retransmitted.

[0089] In the above options 2 to 7, the "dropped HARQ-ACK" may refer to only the dropped HARQ-ACK or all HARQ-ACK bits. In the above options 1 to 7, the dropped HARQ-ACK may be dropped based on at least one of the reasons listed in 1) to 3) below.

[0090] 1) Drop due to UL Cancel indicator (CI). 2) Dropping due to multiplexing within terminal 20. 3) Drop due to TDD collision colliding with invalid symbol. The invalid symbol may be, for example, a semi-static DL symbol, a semi-static flexible symbol due to the SFI indicator and / or SSB / CORESET#0 setting.

[0091] In addition, when an HARQ-ACK with two types of priorities set is retransmitted, the priorities of the retransmitted HARQ-ACK bits may be determined separately or may be determined in combination.

[0092] For example, each priority of the HARQ-ACK bit to be retransmitted may be determined separately, and which of the above options to apply to which priority may be determined independently. Even when the same above option is used, separate configurations or notification may be used. When notification by a DCI field or RRC configuration is selected, separate DCI fields or separate RRC configurations for each priority may be used.

[0093] For example, the priorities of the retransmitted HARQ-ACK bits may be jointly determined, and the same above options may be used. If the DCI field signaling or the RRC configuration is selected, the DCI field signaling or the RRC configuration may be applied to both priorities.

[0094] As a method for determining the resources to be used for retransmitting the HARQ-ACK (C) above, the following method may be applied.

[0095] When HARQ-ACK is retransmitted in PUCCH, for example, in the case of DCI format 1_0, DCI format 1_1, or DCI format 1_2 with or without PDSCH scheduling, or DCI format 0_0, DCI format 0_1, or DCI format 0_2 with or without PUSCH scheduling, the resource for retransmitting HARQ-ACK may be determined as shown in 1) to 3) below. That is, the timing of HARQ-ACK and the PUCCH resource ID may be determined.

[0096] 1) The timing of the HARQ-ACK and the PUCCH resource ID may be defined by the specification. For example, the HARQ-ACK may be transmitted one slot after the slot in which the DCI is received.

[0097] 2) The timing of HARQ-ACK and PUCCH resource ID may be configured by RRC.

[0098] 3) The timing of HARQ-ACK and PUCCH resource ID may be signaled by a new DCI field or an existing DCI field (for example, the HARQ-ACK timing is determined by the PDSCH-to-HARQ_feedback timing indicator field of DCI format 1_0, DCI format 1_1, or DCI format 1_2, and the PUCCH resource ID is signaled by the PRI (PUCCH resource indicator) field). Note that if the DCI that triggers retransmission schedules a PDSCH, the existing PDSCH-to-HARQ_feedback timing indicator field is used to signal the timing of the HARQ-ACK to be retransmitted, and the HARQ-ACK corresponding to the scheduled PDSCH and the HARQ-ACK to be retransmitted have the same priority, the HARQ-ACK corresponding to the scheduled PDSCH may use the same codebook as the HARQ-ACK bits to be retransmitted.

[0099] The HARQ-ACK timing and the PUCCH resource ID may be used independently to determine which of the above 1) to 3) is used.

[0100] In the above 1)-3), when the HARQ-ACKs for which both priorities are set are transmitted separately for each priority, the HARQ-ACK timing and / or PUCCH resource ID, and the HARQ-ACK codebook may be determined separately for each priority, or may be determined jointly.

[0101] When separated for each priority, which of the above options is applied to each priority may be applied independently. When RRC configuration is performed for both priorities, the RRC configuration may be performed separately for each priority. When DCI signaling is performed for both priorities, separate DCI fields for each priority may be used. When the existing PDSCH-to-HARQ_feedback timing indicator field or PRI field is used for HARQ-ACK retransmission, whether it applies to LP or HP may be defined by the specification, may be configured by RRC, or may be signaled by the priority field of the DCI. The HARQ-ACK timing for other priorities may be signaled by a new DCI field, or the HARQ-ACK timing for other priorities may be signaled by reinterpreting an existing unused DCI field.

[0102] In the combined case, one value may be applied for both priorities, as defined by the specification, configured by the RRC, or signaled by a DCI field.

[0103] Regarding the notification of HARQ-ACK timing, the reference point for the K1 value may be the slot in which the DCI is received or the slot notified by the TDRA field.

[0104] On the other hand, when HARQ-ACK is retransmitted in PUSCH, for example, in the case of DCI format 0_0, DCI format 0_1, or DCI format 0_2 with or without UL-SCH scheduling, the resource for retransmitting HARQ-ACK may be determined as shown below.

[0105] The retransmitted HARQ-ACK bits may be multiplexed onto the PUSCH with or without the UL-SCH. The multiplexing parameters, such as the β offset and the scaling factor α, may be determined as shown in 1)-3) below.

[0106] 1) Parameters related to multiplexing may be defined by specifications. For example, β offset=1 and α=1 may be set fixedly in the PUSCH for retransmitting the HARQ-ACK.

[0107] 2) Parameters related to multiplexing may be configured by RRC. Existing settings for multiplexing UCI in PUSCH may be reused, or new settings that are applied only when HARQ-ACK is retransmitted may be added.

[0108] 3) The multiplexing parameters may be signaled in a new DCI field or in an existing DCI field (eg, the β offset field).

[0109] If both priorities are set in the retransmitted HARQ-ACK bits, they may be retransmitted separately for each priority, or the LP HARQ-ACK and HP HARQ-ACK may be coded separately or jointly coded.

[0110] When multiplexing PUSCH, whether to use separate coding or joint coding may be defined in the specification, may be determined by RRC configuration, or may be determined by reusing a new DCI field included in the DCI that triggers retransmission or an existing unused DCI field.

[0111] If decoupled coding is used, the β offset and α values ​​may be determined independently for both priorities or may be determined jointly.

[0112] When the above options are determined separately for each priority, which of the above options to apply to each priority may be applied independently. When RRC configuration is performed for both priorities, the RRC configuration may be performed separately for each priority. When DCI signaling is performed for both priorities, separate DCI fields may be used for each priority. When the existing β offset field is used, whether it applies to LP or HP may be defined by the specification, may be configured by RRC, or may be signaled in the priority field of the DCI. The β offset / α value for the other priorities may be signaled by a new DCI field, or the β offset / α value for the other priorities may be signaled by reinterpreting an existing unused DCI field.

[0113] If joint coding is used, one defined value, one RRC configuration, or one DCI field may apply to both priorities. If joint coding is applied, the β offset and / or α values ​​may be signaled by new DCI fields for the two priorities or by existing DCI fields (e.g., β offset fields).

[0114] Here, in order to configure the HARQ-ACK codebook, the UL-DAI included in the DCI that triggers retransmission may be notified as follows.

[0115] When UL-DAI notification is performed for one priority, for example, the UL-DAI may be notified by a new DCI field or by an existing field (e.g., the 1stDAI index field or the 2ndDAI index field).

[0116] When UL-DAI notification is performed for both priorities (when HARQ-ACK retransmission is triggered for both priorities), notification may be performed as shown in 1)-3) below.

[0117] 1) Two DCI fields may be used to report two DAI values, separated into an LP codebook and an HP codebook. The two DCI fields may be two new DCI fields or existing DCI fields (e.g., a 1stDAI index field and a 2ndDAI index field).

[0118] 2) One DCI field may transmit two DAI values ​​(e.g., separated by the LSB bit and the MSB bit) separated into the LP codebook and the HP codebook. The DCI field may be a new DCI field or an existing DCI field (e.g., the 1stDAI index field or the 2ndDAI index field).

[0119] 3) One DCI field may signal one DAI value to the entire LP codebook and the entire HP codebook, and the DCI field may be a new DCI field or an existing DCI field (e.g., the 1stDAI index field or the 2ndDAI index field).

[0120] As a method for determining the HARQ-ACK codebook to be used for retransmitting the HARQ-ACK (D) above, the following methods 1) to 4) may be applied.

[0121] 1) It may be determined in the same way as the Type 1 HARQ-ACK codebook, that is, the codebook may be configured based on the determination of the HARQ-ACK window and PDSCH opportunity candidates for each serving cell.

[0122] In the first step, the HARQ-ACK bit to be retransmitted is determined, and the HARQ-ACK window including the corresponding slot for PDSCH reception or SPS release is determined. In the second step, the PDSCH opportunity candidates included in the determined HARQ-ACK window are determined. In the third step, the HARQ-ACK bit is generated for the PDSCH opportunity candidate for each slot.

[0123] 2) It may be determined in the same way as the Type 2 HARQ-ACK codebook, that is, the codebook may be configured based on the PDCCH monitoring occasion and the DAI field included in the DCI.

[0124] In the first step, the HARQ-ACK bit to be retransmitted and the corresponding PDSCH reception or SPS release are determined. In the subsequent second step, for dynamic PDSCH reception or SPS release, the HARQ-ACK bits are sorted in the same way as in Release 16. That is, if terminal 20 has notified that it supports PDSCH-Number-perMOperCell, PDSCHs with the same set of serving cell and PDCCH monitoring opportunity are sorted in ascending order by start time, then by serving cell index, and then by PDCCH monitoring opportunity index. In the subsequent third step, the HARQ-ACK bit corresponding to SPS-PDSCH reception is added to the end of the HARQ-ACK bit corresponding to dynamic PDSCH reception or SPS release.

[0125] In the above 2), if the HARQ-ACK codebook includes HARQ-ACK bits with two priorities set, the order of the HARQ-ACK bits may be determined by applying the second and third steps to the HARQ-ACK bits corresponding to the HP sub-codebook, and then applying the second and third steps to the HARQ-ACK bits corresponding to the LP sub-codebook.

[0126] Alternatively, the order of the HARQ-ACK bits may be determined by applying the second step to the HP-HARQ-ACK bits and the LP-HARQ-ACK bits, and then applying the third step to the HP-HARQ-ACK bits and the LP-HARQ-ACK bits. In the second and third steps, the LP-HARQ-ACK bits and the HP-HARQ-ACK bits may be sorted separately. Alternatively, in the second and third steps, the LP-HARQ-ACK bits and the HP-HARQ-ACK bits may be sorted together. Alternatively, in the second step, the LP-HARQ-ACK bits and the HP-HARQ-ACK bits may be sorted separately, and in the third step, the LP-HARQ-ACK bits and the HP-HARQ-ACK bits may be sorted together. Alternatively, in the second step, the LP-HARQ-ACK bits and the HP-HARQ-ACK bits may be sorted together, and in the third step, the LP-HARQ-ACK bits and the HP-HARQ-ACK bits may be sorted separately.

[0127] Fig. 5 is a diagram showing an example (1) of an HARQ-ACK codebook in an embodiment of the present invention. Fig. 5 shows an example in which the order of HARQ-ACK bits is determined by applying the second and third steps to the HARQ-ACK bits corresponding to the HP sub-codebook, and then applying the second and third steps to the HARQ-ACK bits corresponding to the LP sub-codebook.

[0128] Fig. 6 is a diagram showing an example (2) of an HARQ-ACK codebook in an embodiment of the present invention. Fig. 6 shows an example in which the LP-HARQ-ACK bit and the HP-HARQ-ACK bit are separated and sorted in the second and third steps.

[0129] Fig. 7 is a diagram showing an example (3) of an HARQ-ACK codebook in an embodiment of the present invention. Fig. 7 shows an example in which the LP-HARQ-ACK bits and the HP-HARQ-ACK bits are combined and sorted in the second and third steps.

[0130] Fig. 8 is a diagram showing an example (4) of an HARQ-ACK codebook in an embodiment of the present invention. Fig. 8 shows an example in which the LP-HARQ-ACK bit and the HP-HARQ-ACK bit are separated and sorted in the second step, and the LP-HARQ-ACK bit and the HP-HARQ-ACK bit are combined and sorted in the third step.

[0131] Fig. 9 is a diagram showing an example (5) of an HARQ-ACK codebook in an embodiment of the present invention. Fig. 9 shows an example in which the LP-HARQ-ACK bit and the HP-HARQ-ACK bit are combined and sorted in the second step, and the LP-HARQ-ACK bit and the HP-HARQ-ACK bit are separated and sorted in the third step.

[0132] 3) It may be determined similarly to the Type 3 HARQ-ACK codebook, i.e., the codebook may be configured based on the HARQ process AID in each serving cell.

[0133] The first step is to determine the HARQ-ACK bits to be retransmitted and the corresponding PDSCH reception or SPS release. The second step is to sort the HARQ-ACK bits for each serving cell in ascending order of HARQ process ID, and then in ascending order of serving cell index.

[0134] Fig. 10 is a diagram showing an example (6) of an HARQ-ACK codebook in an embodiment of the present invention. Fig. 10 shows an example in which the LP-HARQ-ACK bit and the HP-HARQ-ACK bit are combined to apply the second step.

[0135] Fig. 11 is a diagram showing an example (7) of an HARQ-ACK codebook in an embodiment of the present invention. Fig. 10 is an example in which the second step is applied to the HP-HARQ-ACK bit and then to the LP-HARQ-ACK bit.

[0136] 4) The HARQ-ACK codebook may be configured based on one or more of the following elements a)-e).

[0137] a) PDSCH slot index b) Slot index or subslot index of the HARQ-ACK codebook c) Start or end symbol of PDSCH or SPS release d) Priority (when HARQ-ACK bit has two priorities) e) Serving Cell Index

[0138] Fig. 12 is a diagram showing an example (8) of a HARQ-ACK codebook in an embodiment of the present invention. Fig. 12 shows an example of a HARQ-ACK bit order sorted based on d) above, then c) above, and then e).

[0139] The method of configuring the HARQ-ACK codebook shown in 1)-4) above may be determined depending on the RRC parameter pdsch-HARQ-ACK-Codebook or may be determined independently. For example, if the pdsch-HARQ-ACK-Codebook is semi-static, method 1) may be used. For example, if the pdsch-HARQ-ACK-Codebook is dynamic, method 2) may be used.

[0140] Furthermore, which of the HARQ-ACK codebook configuration methods shown in 1)-4) above is to be used may be defined by the specifications, may be set by RRC, or may be notified by a new DCI field included in the DCI that triggers retransmission or by reinterpretation of an existing DCI field.

[0141] In the above-described embodiments, which process or method is used may be set by higher layer parameters, may be determined based on the UE capabilities reported by the terminal 20, may be predefined in the specifications, or may be determined based on the higher layer parameters and the UE capabilities.

[0142] In addition, when using a configuration method similar to that of the Type 3 HARQ-ACK codebook, for example, retransmission of HARQ-ACK may be triggered by DCI format 1_1, and HARQ-ACK bits corresponding to all configured HARQ-ACK process IDs for each serving cell may be retransmitted, or the resource for retransmitting the HARQ-ACK bits may be determined by the specifications to be, for example, fixedly one slot after the DCI reception slot.

[0143] The UE capabilities shown in 1)-2) below may be defined.

[0144] 1) UE capability indicating whether or not to support enhanced features regarding DCI-triggered HARQ-ACK retransmission.

[0145] 2) UE capability indicating whether it supports a single DCI triggering multiple HARQ-ACK retransmissions.

[0146] (Device configuration) Next, a description will be given of an example of the functional configuration of the base station 10 and the terminal 20 that execute the processes and operations described above. The base station 10 and the terminal 20 include functions for executing the above-described embodiments. However, the base station 10 and the terminal 20 may each include only one of the functions of the embodiments.

[0147] <Base station 10> Fig. 13 is a diagram showing an example of the functional configuration of the base station 10. As shown in Fig. 13, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 13 is merely an example. The names of the functional divisions and functional units may be any as long as they can perform the operations related to the embodiment of the present invention. The transmitting unit 110 and the receiving unit 120 may be called a communication unit.

[0148] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signal. The transmitter 110 also has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL data, etc. to the terminal 20. The transmitter 110 also transmits the setting information, etc., described in the embodiments.

[0149] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20 in a storage device, and reads out the information from the storage device as needed. The control unit 140 performs, for example, resource allocation and overall control of the base station 10. Note that the functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120. Furthermore, the transmitting unit 110 and the receiving unit 120 may be called a transmitter and a receiver, respectively.

[0150] <Terminal 20> Fig. 14 is a diagram showing an example of the functional configuration of the terminal 20. As shown in Fig. 14, the terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 14 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention. The transmitting unit 210 and the receiving unit 220 may be called a communication unit.

[0151] The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires higher layer signals from the received physical layer signals. The transmitter 210 also transmits HARQ-ACK, and the receiver 220 receives the setting information and the like described in the embodiments.

[0152] The setting unit 230 stores various setting information received from the base station 10 by the receiving unit 220 in a storage device, and reads it out from the storage device as needed. The setting unit 230 also stores setting information that is set in advance. The control unit 240 performs overall control of the terminal 20. Note that the functional unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and the functional unit related to signal reception in the control unit 240 may be included in the receiving unit 220. Note that the transmitting unit 210 and the receiving unit 220 may be called a transmitter and a receiver, respectively.

[0153] (Summary of the embodiment) As described above, according to an embodiment of the present invention, there is provided a terminal including: a receiving unit that receives data and control information that triggers retransmission of a hybrid automatic repeat request (HARQ) response corresponding to the data; a control unit that determines an HARQ response to be retransmitted when the receiving unit receives the control information; and a transmitting unit that transmits the HARQ response to be retransmitted, wherein the control unit determines the response to be retransmitted based at least on a priority set in the HARQ response.

[0154] With the above configuration, when terminal 20 receives DCI that triggers retransmission of a dropped HARQ-ACK, terminal 20 can determine which HARQ-ACK bits to retransmit, taking into account conditions including priority, which resources to use to retransmit the HARQ-ACK bits, and determine the HARQ-ACK codebook to apply to the retransmission. That is, the terminal can retransmit the dropped feedback information corresponding to the reception of data to the base station.

[0155] The control unit may determine the granularity of the offset value from the data to the corresponding HARQ response based on the HARQ response to which a higher priority is set. With this configuration, the terminal 20 can set the timing of retransmitting the HARQ-ACK according to the priority.

[0156] The control unit may include, in the HARQ response to be retransmitted, a HARQ response whose transmission has been dropped among HARQ responses generated in a specific period before receiving the control information. With this configuration, when terminal 20 receives DCI that triggers retransmission of a dropped HARQ-ACK, terminal 20 can determine which HARQ-ACK bit to retransmit, taking into account conditions including priority.

[0157] When multiple priorities are set for the HARQ response, the control unit may determine resources for transmitting the HARQ response to be retransmitted separately for each priority. With this configuration, when terminal 20 receives DCI that triggers retransmission of a dropped HARQ-ACK, terminal 20 can determine which resource to use to retransmit the HARQ-ACK bit, taking into account conditions including the priority.

[0158] When multiple priorities are set for the HARQ response, the control unit may determine a codebook to be applied to the HARQ response to be retransmitted separately for each priority. When terminal 20 receives DCI that triggers retransmission of a dropped HARQ-ACK, terminal 20 can determine a HARQ-ACK codebook taking into account conditions including the priority.

[0159] Furthermore, according to an embodiment of the present invention, there is provided a communication method in which a terminal executes the procedure of determining the response to be retransmitted based at least on a priority set in the HARQ response, the procedure including: a reception procedure for receiving data and control information for triggering a retransmission of a hybrid automatic repeat request (HARQ) response corresponding to the data; a control procedure for determining the HARQ response to be retransmitted when the control information is received by the reception procedure; and a transmission procedure for transmitting the HARQ response to be retransmitted.

[0160] With the above configuration, when terminal 20 receives DCI that triggers retransmission of a dropped HARQ-ACK, terminal 20 can determine which HARQ-ACK bits to retransmit, taking into account conditions including priority, which resources to use to retransmit the HARQ-ACK bits, and determine the HARQ-ACK codebook to apply to the retransmission. That is, the terminal can retransmit the dropped feedback information corresponding to the reception of data to the base station.

[0161] (Hardware configuration) The block diagrams (FIGS. 13 and 14) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are connected directly or indirectly (for example, by wire, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining the single device or the multiple devices with software.

[0162] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

[0163] For example, the base station 10, the terminal 20, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 15 is a diagram illustrating an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The base station 10 and the terminal 20 described above may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0164] In the following description, the term "apparatus" can be read as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0165] Each function in the base station 10 and the terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001, the memory device 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls at least one of reading and writing data in the memory device 1002 and the auxiliary memory device 1003.

[0166] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0167] Furthermore, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 140 of the base station 10 shown in FIG. 13 may be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. Furthermore, for example, the control unit 240 of the terminal 20 shown in FIG. 14 may be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. While the above-described various processes have been described as being executed by one processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0168] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0169] The secondary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0170] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0171] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0172] Furthermore, each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0173] Furthermore, base station 10 and terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, processor 1001 may be implemented using at least one of these pieces of hardware.

[0174] (Supplementary explanation of the embodiment) Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention; two or more items may be combined as needed, and items described in one item may apply to items described in another item (unless inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of the processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams. However, such devices may be implemented using hardware, software, or a combination thereof. The software operated by the processor of the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

[0175] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0176] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (New Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark), IEEE 802.20, UWB (Ultra-Wideband), Bluetooth (registered trademark), or other appropriate systems, and next-generation systems extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0177] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order and are not limited to the particular order presented.

[0178] In this specification, a specific operation that is described as being performed by the base station 10 may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and another network node other than the base station 10 (such as, but not limited to, an MME or an S-GW). Although the above example illustrates a case where there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (such as an MME and an S-GW).

[0179] The information, signals, etc. described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0180] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be sent to another device.

[0181] In the present disclosure, the determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0182] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0183] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0184] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0185] Note that terms explained in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0186] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0187] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0188] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0189] In this disclosure, terms such as "base station (BS)," "radio base station," "base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0190] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication service within this coverage.

[0191] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0192] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0193] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile body, or the mobile body itself. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0194] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between a plurality of terminals 20 (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0195] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0196] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0197] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0198] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0199] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0200] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0201] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0202] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0203] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0204] Numerology may be communication parameters that apply to at least one of transmission and reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0205] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may be a time unit based on numerology.

[0206] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0207] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0208] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc. instead of a subframe.

[0209] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0210] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0211] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0212] A TTI having a time length of 1 ms may be called a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0213] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0214] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may also be determined based on numerology.

[0215] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0216] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, or the like.

[0217] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0218] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0219] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be set for the terminal 20 within one carrier.

[0220] At least one of the configured BWPs may be active, and the terminal 20 may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell," "carrier," and the like in this disclosure may be read as "BWP."

[0221] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0222] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0223] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0224] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0225] In the present disclosure, HARQ-ACK is an example of a HARQ response, and DCI that triggers a retransmission is an example of control information that requests a retransmission of a response corresponding to data.

[0226] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure. [Explanation of symbols]

[0227] 10 base station 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 terminals 210 Transmitter 220 Receiving unit 230 Setting Section 240 Control Unit 1001 processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output Device

Claims

1. a receiving unit that receives, from a base station, data and control information that does not involve scheduling, the control information including a field that instructs retransmission of a hybrid automatic repeat request (HARQ) response corresponding to the data and a field that instructs priority of the HARQ response; a control unit that, when the receiving unit receives the control information, determines a HARQ response to retransmit based on the priority, a window size defined in advance by a specification, and an offset obtained by reinterpreting an existing field included in the control information; a transmitting unit that transmits the HARQ response to be retransmitted to the base station.

2. A communication method performed by a terminal, comprising: receiving, from a base station, data and control information that does not involve scheduling, the control information including a field indicating a retransmission of a hybrid automatic repeat request (HARQ) response corresponding to the data and a field indicating a priority of the HARQ response; When the control information is received, determining a HARQ response to retransmit based on the priority, a window size predefined in a specification, and an offset obtained by reinterpreting an existing field included in the control information; transmitting the HARQ response to be retransmitted to the base station.

3. A wireless communication system including a terminal and a base station, the base station transmits to the terminal data and control information that does not involve scheduling, the control information including a field instructing retransmission of a Hybrid Automatic Repeat Request (HARQ) response corresponding to the data and a field instructing priority of the HARQ response; The terminal receiving the data and the control information; When the control information is received, determining a HARQ response to be retransmitted based on the priority, a window size predefined in a specification, and an offset obtained by reinterpreting an existing field included in the control information; The wireless communication system further comprises: a base station configured to transmit the HARQ response to be retransmitted;

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