Terminal and communication method

Abstract

A terminal has a reception section that receives one or more pieces of information from a base station, the one or more pieces of information specifying a plurality of codebooks for transmitting acknowledgments related to retransmission control applied to transceiving in a downlink; a control section that decides a codebook, among the plurality of codebooks, for transmitting an acknowledgment related to retransmission control applied to transceiving in a sidelink; and a transmission section that transmits one or more acknowledgments related to retransmission control applied to transceiving in the sidelink to the base station using the decided codebook.

Description

Technical Field

[0001] This invention relates to terminals and communication methods in wireless communication systems. Background Technology

[0002] In LTE (Long Term Evolution) and its successor systems (e.g., LTE-A (LTE Advanced), NR (New Radio) (also known as 5G)), D2D (Device to Device) technology, which enables direct communication between terminals without going through a base station, has been studied (e.g., non-patent literature 1).

[0003] D2D reduces the traffic load between terminals and base stations, enabling communication between terminals even when base stations cannot communicate, such as during disasters. Furthermore, in 3GPP (3rd Generation Partnership Project), D2D is referred to as a "sidelink," but in this specification, the more general term D2D is used. However, in the description of the implementation methods described later, "sidelink" may also be used as needed.

[0004] D2D communication can be broadly divided into D2D discovery (also known as D2D discovery), used to discover other terminals capable of communication, and D2D direct communication (also known as D2D communication, direct communication between terminals, etc.), used for direct communication between terminals. Hereinafter, without specifically distinguishing between D2D communication and D2D discovery, it will be simply referred to as D2D. Furthermore, signals transmitted and received via D2D are referred to as D2D signals. Various use cases of services related to V2X (Vehicle to Everything) in NR were studied (e.g., non-patent literature 2).

[0005] Existing technical documents

[0006] Non-patent literature

[0007] Non-patent document 1: 3GPP TS 38.211V16.2.0 (2020-06)

[0008] Non-patent document 2: 3GPP TR 22.886V15.1.0 (2017-03) Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In NR sidelink version 16, the terminal can report HARQ (Hybrid Automatic Repeat Request)-ACKs from the sidelink to the base station via the uplink. Furthermore, when multiplexing HARQ-ACK bits from multiple sidelinks, a HARQ-ACK codebook can be used.

[0011] In this case, there may be multiple HARQ-ACK codebooks configured for the downlink. When multiple HARQ-ACK codebooks are configured, it is unclear which HARQ-ACK codebook the terminal uses when reporting to the base station that "multiplexes the HARQ-ACK bits in multiple sidelinks".

[0012] The present invention was made in view of the above, and its purpose is to report multiple HARQ (Hybrid automatic repeat request)-ACK reports to the base station in direct communication between terminals.

[0013] means for solving problems

[0014] According to the disclosed technology, a terminal is provided, comprising: a receiving unit that receives one or more pieces of information from a base station, the one or more pieces of information specifying a plurality of codebooks, the plurality of codebooks being used to send a response related to retransmission control applied to transmission and reception in the downlink; a control unit that determines one of the plurality of codebooks for sending a response related to retransmission control applied to transmission and reception in the sidelink; and a sending unit that uses the determined codebook to send one or more responses related to retransmission control applied to transmission and reception in the sidelink to the base station.

[0015] Invention Effects

[0016] According to publicly available technology, in direct communication between terminals, multiple HARQ (Hybrid automatic repeat request)-ACK reports can be sent to the base station. Attached Figure Description

[0017] Figure 1 This is a diagram used to illustrate V2X.

[0018] Figure 2 This is a diagram used to illustrate the transmission mode of V2X (1).

[0019] Figure 3 This is a diagram used to illustrate the transmission mode of V2X (2).

[0020] Figure 4 This is a diagram used to illustrate the transmission mode of V2X (3).

[0021] Figure 5 This is a diagram used to illustrate the transmission mode of V2X (4).

[0022] Figure 6 This is a diagram used to illustrate the transmission mode of V2X (5).

[0023] Figure 7 This is a diagram illustrating example (1) of the communication types in V2X.

[0024] Figure 8 This is a diagram used to illustrate example (2) of the V2X communication type.

[0025] Figure 9 This is a diagram used to illustrate the communication type of V2X (3).

[0026] Figure 10 This is a timing diagram showing the action example (1) of V2X.

[0027] Figure 11 This is a timing diagram showing the action example (2) of V2X.

[0028] Figure 12 This is a timing diagram showing the action example (3) of V2X.

[0029] Figure 13 This is a timing diagram showing the action example (4) of V2X.

[0030] Figure 14 This is a diagram illustrating an example of a HARQ-ACK action that is reported as reused.

[0031] Figure 15 This is a flowchart illustrating an example of the HARQ-ACK reporting action in an embodiment of the present invention.

[0032] Figure 16 This is a diagram illustrating an example of the functional structure of base station 10 in an embodiment of the present invention.

[0033] Figure 17 This is a diagram illustrating an example of the functional structure of terminal 20 in an embodiment of the present invention.

[0034] Figure 18 This is a diagram illustrating an example of the hardware structure of a base station 10 or a terminal 20 in an embodiment of the present invention. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the embodiments described below are merely examples, and the application of the present invention is not limited to the embodiments described below.

[0036] When the wireless communication system according to the embodiments of the present invention is in operation, existing technologies are appropriately used. However, such existing technologies are, for example, existing LTE, but are not limited to existing LTE. Furthermore, unless otherwise stated, the term "LTE" as used in this specification has a broad meaning that includes LTE-Advanced and LTE-Advanced and later modes (e.g., NR) or wireless LAN (Local Area Network).

[0037] Furthermore, in embodiments of the present invention, the duplex mode can be TDD (Time Division Duplex), FDD (Frequency Division Duplex), or other modes (e.g., Flexible Duplex).

[0038] Furthermore, in embodiments of the present invention, the “configure” wireless parameters can be preset values ​​or wireless parameters notified from base station 10 or terminal 20.

[0039] Figure 1 This diagram illustrates V2X. Within 3GPP, technologies for implementing V2X (Vehicle to Everything) or eV2X (enhanced V2X) by extending D2D functionality are being studied and standardized. Figure 1 As shown, V2X is a part of ITS (Intelligent Transport Systems). It is a collective term for V2V (Vehicle to Vehicle), V2I (Vehicle to Infrastructure), V2N (Vehicle to Network), and V2P (Vehicle to Pedestrian), which are communication forms between vehicles, roadside units (RSUs) located beside the road.

[0040] Furthermore, 3GPP is researching V2X using LTE or NR cellular communication and inter-terminal communication. V2X using cellular communication is also referred to as cellular V2X. In NR V2X, research is underway to achieve high capacity, low latency, high reliability, and QoS (Quality of Service) control.

[0041] Regarding V2X for LTE or NR, it is envisioned that future research could be advanced beyond 3GPP specifications. For example, research is envisioned on ensuring interoperability, reducing costs incurred due to higher-level installations, methods for the concurrent use or switching of multiple RATs (Radio Access Technologies), regulatory support in various countries, and methods for data acquisition, distribution, database management, and usage on LTE or NR V2X platforms.

[0042] In the embodiments of the present invention, the communication device is primarily envisioned as being mounted on a vehicle; however, the embodiments of the present invention are not limited to this method. For example, the communication device can be a terminal held by a person, a device mounted on a drone or aircraft, or a base station, RSU, relay station (Relay Node), terminal with scheduling capabilities, etc.

[0043] Additionally, SL (Sidelink) can also be distinguished by UL (Uplink) or DL ​​(Downlink) and any one or a combination of 1)-4) below. Furthermore, SL can also be other names.

[0044] 1) Resource allocation in the time domain

[0045] 2) Frequency domain resource allocation

[0046] 3) Reference synchronization signals (including SLSS (Sidelink Synchronization Signal))

[0047] 4) Reference signal used in path loss measurement for transmission power control

[0048] In addition, for SL or UL OFDM (Orthogonal Frequency Division Multiplexing), any of the following can be used: CP-OFDM (Cyclic-Prefix OFDM), DFT-S-OFDM (Discrete Fourier Transform-Spread-OFDM), OFDM without transform precoding, or OFDM with transform precoding.

[0049] In LTE's SL (Send-On) architecture, two modes, Mode 3 and Mode 4, are specified for resource allocation to terminal 20. In Mode 3, transmission resources are dynamically allocated using DCI (Downlink Control Information) sent from base station 10 to terminal 20. Furthermore, SPS (Semi-Persistent Scheduling) is also possible in Mode 3. In Mode 4, terminal 20 autonomously selects transmission resources from the resource pool.

[0050] In addition, the slot in the embodiments of the present invention can also be replaced by symbol, mini slot, subframe, radio frame, or TTI (Transmission Time Interval). Furthermore, the cell in the embodiments of the present invention can also be replaced by cell group, carrier component, BWP, resource pool, resource, RAT (Radio Access Technology), system (including wireless LAN), etc.

[0051] Furthermore, in embodiments of the present invention, terminal 20 is not limited to a V2X terminal, but can be any type of terminal performing D2D communication. For example, terminal 20 can be a user-owned terminal such as a smartphone, or an IoT (Internet of Things) device such as a smart meter.

[0052] Figure 2 This is a diagram used to illustrate example (1) of the V2X transmission mode. In Figure 2In the sidelink communication transmission mode shown, in step 1, base station 10 sends sidelink scheduling information to terminal 20A. Then, terminal 20A, based on the received scheduling information, sends PSCCH (Physical Sidelink Control Channel) and PSSCH (Physical Sidelink Shared Channel) to terminal 20B (step 2). Alternatively... Figure 2 The sidelink communication transmission mode shown is called sidelink transmission mode 3 in LTE. In sidelink transmission mode 3 in LTE, sidelink scheduling is performed based on Uu. Uu refers to the radio interface between the UTRAN (Universal Terrestrial Radio Access Network) and the UE (User Equipment). Alternatively, it can also be... Figure 2 The sidelink communication transmission mode shown is called sidelink transmission mode 1 in NR.

[0053] Figure 3 This is a diagram illustrating example (2) of the V2X transmission mode. In Figure 3 In the side-link communication transmission mode shown, in step 1, terminal 20A uses autonomously selected resources to send PSCCH and PSSCH to terminal 20B. Alternatively... Figure 3 The sidelink communication transmission mode shown is called sidelink transmission mode 4 in LTE. In sidelink transmission mode 4 in LTE, the UE performs resource selection itself.

[0054] Figure 4 This is a diagram used to illustrate example (3) of the V2X transmission mode. In Figure 4 In the side-link communication transmission mode shown, in step 1, terminal 20A uses autonomously selected resources to send PSCCH and PSSCH to terminal 20B. Similarly, terminal 20B uses autonomously selected resources to send PSCCH and PSSCH to terminal 20A (step 1). Alternatively... Figure 4 The sidelink communication transmission mode shown is called sidelink transmission mode 2a in NR. In sidelink transmission mode 2a in NR, terminal 20 performs resource selection itself.

[0055] Figure 5 This is a diagram used to illustrate example (4) of the V2X transmission mode. In Figure 5In the sidelink communication transmission mode shown, in step 0, the base station 10 sends the sidelink resource mode to the terminal 20A via RRC (Radio Resource Control), or a sidelink resource mode is preset. Then, the terminal 20A sends PSSCH to the terminal 20B according to the resource mode (step 1). Alternatively... Figure 5 The sidelink communication transmission mode shown is called sidelink transmission mode 2c in NR.

[0056] Figure 6 This is a diagram used to illustrate example (5) of the V2X transmission mode. In Figure 6 In the sidelink communication transmission mode shown, in step 1, terminal 20A sends sidelink scheduling information to terminal 20B via PSCCH. Then, terminal 20B sends PSSCH to terminal 20A according to the received scheduling information (step 2). Alternatively... Figure 6 The sidelink communication transmission mode shown is called sidelink transmission mode 2d in NR.

[0057] Figure 7 This is a diagram illustrating example (1) of the communication types in V2X. Figure 7 The communication type of the side link shown is unicast. Terminal 20A sends PSCCH and PSSCH to terminal 20. Figure 7 In the example shown, terminal 20A unicasts to terminal 20B and unicasts to terminal 20C.

[0058] Figure 8 This is a diagram used to illustrate example (2) of the V2X communication type. Figure 8 The sidelink communication type shown is multicast. Terminal 20A sends PSCCH and PSSCH to one or more groups to which terminal 20 belongs. Figure 8 In the example shown, the group includes terminal 20B and terminal 20C, and terminal 20A multicasts to the group.

[0059] Figure 9 This is a diagram used to illustrate the communication type of V2X (3). Figure 9 The communication type of the side link shown is broadcast. Terminal 20A sends PSCCH and PSSCH to one or more terminals 20. Figure 9 In the example shown, terminal 20A broadcasts to terminals 20B, 20C, and 20D. Alternatively, it can also... Figures 7-9 The terminal 20A shown is called the header UE.

[0060] Furthermore, NR-V2X envisions supporting HARQ (Hybrid Automatic Repeat Request) in both unicast and multicast on sidelinks. Additionally, NR-V2X defines SFCI (Sidelink Feedback Control Information) that includes HARQ responses. Moreover, the transmission of SFCI via PSFCH (Physical Sidelink Feedback Channel) is under investigation.

[0061] Furthermore, in the following description, it is assumed that PSFCH is used for HARQ-ACK transmission in the side link, but this is only one example. For example, PSCCH, PSSCH, and other channels can be used for HARQ-ACK transmission in the side link.

[0062] For ease of explanation, all information reported by terminal 20 in HARQ will be referred to as HARQ-ACK. This HARQ-ACK can also be called HARQ-ACK information. More specifically, the codebook used for the HARQ-ACK information reported from terminal 20 to base station 10, etc., is called the HARQ-ACK codebook. The HARQ-ACK codebook specifies the bit string of the HARQ-ACK information. In addition to ACK, NACK is also sent using "HARQ-ACK".

[0063] Figure 10 This is a timing diagram illustrating the action example (1) of V2X. For example... Figure 10 As shown, the wireless communication system of this embodiment of the invention can have terminal 20A and terminal 20B. In addition, multiple user devices are actually present, but... Figure 10 Terminals 20A and 20B are shown as examples.

[0064] Hereinafter, without specifically distinguishing between terminals 20A, 20B, etc., they will simply be referred to as "Terminal 20" or "User Equipment". Figure 10 As an example, the example shows a situation where both terminal 20A and terminal 20B are within the coverage area of ​​the cell. However, the actions in this embodiment of the invention can also be applied to situations where terminal 20B is outside the coverage area.

[0065] As described above, in this embodiment, terminal 20 is, for example, a device mounted in a vehicle such as an automobile, and has cellular communication functions as a UE in LTE or NR, as well as sidelink functions. Terminal 20 can also be a general portable terminal (such as a smartphone). Furthermore, terminal 20 can also be an RSU. This RSU can be a UE-type RSU with UE functions, or a gNB-type RSU with base station functions.

[0066] In addition, terminal 20 does not need to be a device with a housing. For example, even if various sensors are distributed throughout the vehicle, the device including these various sensors can also be terminal 20.

[0067] Furthermore, the processing of data transmitted via the sidelink of terminal 20 is essentially the same as that of UL transmission in LTE or NR. For example, terminal 20 scrambles and modulates the codewords of the transmitted data to generate complex-valued symbols, maps these complex-valued symbols (transmitted signals) to layer 1 or layer 2, and performs precoding. Then, the precoded complex-valued symbols are mapped to resource elements to generate a transmitted signal (e.g., complex-valued time-domain SC-FDMA signal) and transmitted from each antenna port.

[0068] Furthermore, regarding base station 10, it has cellular communication functions as a base station in LTE or NR, and functions for enabling terminal 20 in this embodiment to communicate (e.g., resource pool setting, resource allocation, etc.). Additionally, base station 10 can also be an RSU (gNB type RSU).

[0069] Furthermore, in the wireless communication system of the present invention, the signal waveform used by the terminal 20 in SL or UL can be OFDMA, SC-FDMA, or other signal waveforms.

[0070] In step S101, terminal 20A autonomously selects resources from the PSCCH and PSSCH from a resource selection window with a predetermined period. The resource selection window can also be set by base station 10 for terminal 20. Here, the predetermined period of the resource selection window can be specified based on terminal installation conditions such as processing time or maximum allowable packet delay time, or it can be predetermined according to specifications. The predetermined period can also be referred to as a time-domain interval.

[0071] In steps S102 and S103, terminal 20A uses the resources autonomously selected in step S101 to transmit SCI (Sidelink Control Information) using PSCCH and / or PSSCH, and transmit SL data using PSSCH. For example, terminal 20A can transmit PSCCH using frequency resources adjacent to the frequency resources of PSSCH within at least a portion of the time resources that are the same as the time resources of PSSCH.

[0072] Terminal 20B receives SCI (PSCCH and / or PSSCH) and SL data (PSSCH) sent from terminal 20A. The received SCI may contain information about the resources used by terminal 20B to send a HARQ-ACK for the received data via PSFCH. Terminal 20A may include information about resources it autonomously selects in the SCI and send it.

[0073] In step S104, terminal 20B uses the resources of PSFCH determined by the received SCI to send HARQ-ACK for the received data to terminal 20A.

[0074] If the HARQ-ACK received in step S104 is a NACK (negative acknowledgment) indicating a request for retransmission, then in step S105, terminal 20A retransmits the PSCCH and PSSCH to terminal 20B. Terminal 20A may use resources it autonomously selects to retransmit the PSCCH and PSSCH.

[0075] Alternatively, steps S104 and S105 may be omitted if HARQ control with HARQ feedback is not performed.

[0076] Figure 11 This is a timing diagram illustrating a V2X action example (2). Blind retransmissions can also be performed, independent of HARQ control used to improve transmission success rate or arrival distance.

[0077] In step S201, terminal 20A autonomously selects the resources to be used in PSCCH and PSSCH from a resource selection window with a predetermined period. The resource selection window can also be set by base station 10 for terminal 20.

[0078] In steps S202 and S203, terminal 20A uses the resources autonomously selected in step S201 to transmit SCI using PSCCH and / or PSSCH, and transmits SL data using PSSCH. For example, terminal 20A can transmit PSCCH using frequency resources adjacent to the frequency resources of PSSCH in at least a portion of the time resources that are the same as the time resources of PSSCH.

[0079] In step S204, terminal 20A uses the resources autonomously selected in step S201 to retransmit SCI data based on PSCCH and / or PSSCH and SL data based on PSSCH to terminal 20B. The retransmission in step S204 can be performed multiple times.

[0080] Alternatively, step S204 can be omitted if blind retransmission is not performed.

[0081] Figure 12 This is a timing diagram illustrating an example of V2X operation (3). Base station 10 can perform sidelink scheduling. That is, base station 10 can determine the resources of the sidelink used by terminal 20 and send information representing those resources to terminal 20. Furthermore, when applying HARQ control with HARQ feedback, base station 10 can send information representing the resources of PSFCH to terminal 20.

[0082] In step S301, base station 10 uses PDCCH to send DCI (Downlink Control Information) to terminal 20A, thereby performing SL scheduling. For ease of explanation, the DCI used for SL scheduling will be referred to as SL scheduling DCI.

[0083] Furthermore, the following scenario is envisioned: In step S301, base station 10 also sends a DCI for DL ​​scheduling (also known as DL allocation) to terminal 20A using PDCCH. For ease of explanation, the DCI for DL ​​scheduling will be referred to as DL scheduling DCI. Terminal 20A, upon receiving the DL scheduling DCI, uses the resources specified by the DL scheduling DCI to receive DL data using PDSCH.

[0084] In steps S302 and S303, terminal 20A uses the resources specified by the SL scheduling DCI to send SCI (Sidelink Control Information) using PSCCH and / or PSSCH, and also sends SL data using PSSCH. Alternatively, the SL scheduling DCI may specify only the resources for PSSCH. In this case, for example, terminal 20A may send PSCCH using frequency resources adjacent to the frequency resources of PSSCH, within at least a portion of the time resources that are identical to the time resources of PSSCH.

[0085] Terminal 20B receives SCI (PSCCH and / or PSSCH) and SL data (PSSCH) sent from terminal 20A. The SCI received using PSCCH and / or PSSCH contains information about the resources for "PSFCH for terminal 20B to send HARQ-ACK for the reception of the data".

[0086] The information about the resource is included in the DL scheduling DCI or SL scheduling DCI sent from base station 10 in step S301. Terminal 20A obtains the information about the resource from the DL scheduling DCI or SL scheduling DCI and includes it in the SCI. Alternatively, assuming that the DCI sent from base station 10 does not contain the information about the resource, terminal 20A autonomously includes the information about the resource in the SCI and sends it.

[0087] In step S304, terminal 20B uses the resources of PSFCH determined by the received SCI to send HARQ-ACK for the received data to terminal 20A.

[0088] In step S305, terminal 20A, for example, at a timing specified by the DL scheduling DCI (or SL scheduling DCI) (e.g., timing in time slots), uses the PUCCH (Physical uplink control channel) resources specified by the DL scheduling DCI (or the SL scheduling DCI) to send a HARQ-ACK, and base station 10 receives the HARQ-ACK. The codebook of this HARQ-ACK may contain the HARQ-ACK received from terminal 20B, or an HARQ-ACK generated based on an unreceived PSFCH, and a HARQ-ACK for DL ​​data. However, in cases where no DL data is allocated, etc., it does not contain a HARQ-ACK for DL ​​data. In Rel. 16 of NR, the codebook of this HARQ-ACK does not contain a HARQ-ACK for DL ​​data.

[0089] Alternatively, steps S304 and / or S305 may be omitted if HARQ control with HARQ feedback is not performed.

[0090] Figure 13 This is a timing diagram illustrating a V2X operation example (4). As described above, the following scenario is supported: HARQ responses are sent via PSFCH in the NR side link. Furthermore, the PSFCH format can, for example, use the same format as PUCCH (Physical Uplink Control Channel) format 0. That is, the PSFCH format can be a sequence-based format with a PRB (Physical Resource Block) size of 1, where ACK and NACK are identified based on timing and / or cyclic shift differences. The PSFCH format is not limited to this. PSFCH resources can be configured in symbols at the end of a time slot or multiple symbols at the end. Furthermore, a period N is set or predefined for the PSFCH resources. The period N can be set or predefined in units of time slots.

[0091] exist Figure 13 In the diagram, the vertical axis corresponds to the frequency domain, and the horizontal axis corresponds to the time domain. The PSCCH can be configured with one symbol at the beginning of a time slot, or multiple symbols starting from the beginning, or multiple symbols starting from symbols other than the beginning. The PSFCH can be configured with one symbol at the end of a time slot, or multiple symbols at the end of a time slot. Furthermore, the terms "start of time slot" and "end of time slot" can omit consideration of symbols used for AGC (Automatic Gain Control) and symbols used for transmit / receive switching. That is, for example, in the case where one time slot consists of 14 symbols, "start of time slot" and "end of time slot" can mean the first and last symbols in the remaining 12 symbols. Figure 13 In the example shown, three sub-channels are configured in the resource pool, and two PSFCHs are configured after the three time slots configured with PSSCHs. The arrows from PSSCH to PSFCHs indicate an example of a PSFCH associated with a PSSCH.

[0092] In NR-V2X multicast, where the HARQ response is multicast option 2 (sending ACK or NACK), it is necessary to determine the resources used for sending and receiving the PSFCH. For example... Figure 13As shown, in step S401, terminal 20A, acting as the transmitting terminal 20, performs multicast to terminals 20B, 20C, and 20D, acting as the receiving terminal 20, via SL-SCH. In the following step S402, terminal 20B sends a HARQ response to terminal 20A using PSFCH#B, terminal 20C sends a HARQ response to terminal 20A using PSFCH#C, and terminal 20D sends a HARQ response to terminal 20A using PSFCH#D. Here, as... Figure 13 As shown in the example, when the number of available PSFCH resources is less than the number of receiving terminals 20 belonging to the group, it is necessary to decide how to allocate the PSFCH resources. Additionally, the sending terminal 20 can know the number of receiving terminals 20 in the multicast. Furthermore, in multicast option 1, only NACK is sent as a HARQ response, without sending ACK.

[0093] In NR sidelink version 16, terminal 20 can report HARQ-ACKs in the sidelink to base station 10. Furthermore, terminal 20 can multiplex HARQ-ACKs from multiple sidelinks and report them to base station 10. The set of HARQ-ACK bits when more than one HARQ-ACK bit is transmitted via a channel can also be referred to as the HARQ-ACK codebook. The HARQ-ACK codebook supports both semi-static Type 1 and dynamic Type 2. When reporting HARQ-ACKs in the sidelink from terminal 20 to base station 10, which type of HARQ-ACK codebook (Type 1 or Type 2) is used depends on the codebook used in the downlink HARQ-ACK.

[0094] For the codebook used in HARQ feedback corresponding to downlink reception, in NR eURLLC (enhanced Ultra-Reliable and Low Latency Communications) version 16, up to two codebook types can be set for a terminal 20. One codebook type corresponds to low priority, and the other corresponds to high priority.

[0095] Furthermore, regarding the codebook used for HARQ feedback corresponding to downlink reception, in NR version 16, when two PUCCH groups are configured in a cell group, a maximum of two codebook types can be configured for a terminal 20. One codebook type is configured in each PUCCH group.

[0096] As mentioned above, given that there are multiple codebook types configured for the codebook used in the downlink HARQ-ACK, it is unclear which codebook should be used in the sidelink HARQ feedback (when the terminal 20 reports the sidelink HARQ-ACK to the base station 10). Furthermore, the sidelink HARQ-ACK codebook is applied to... Figure 12 The HARQ-ACK sent by PUCCH or PUSCH in step S305 shown can also be applied to the HARQ-ACK sent by PSFCH in step S303.

[0097] In version 16 of the aforementioned NR eURLLC, up to two codebook types for a terminal 20 are set to semi-static or dynamic via the RRC information element "pdsch-HARQ-ACK-CodebookList-r16" notified from base station 10. The first codebook type contained in this RRC information element corresponds to low priority, and the second codebook type corresponds to high priority. Hereinafter, "pdsch-HARQ-ACK-CodebookList-r16" is referred to as "pdsch-HARQ-ACK-CodebookList".

[0098] Furthermore, in NR version 16 mentioned above, when two PUCCH groups are configured in a cell group, the codebook type corresponding to the secondary PUCCH group is set to semi-static or dynamic via the RRC information element "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup-r16" notified from base station 10. Hereinafter, "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup-r16" will be referred to as "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup".

[0099] Furthermore, when the codebook type is used normally or when a cell group has two PUCCH groups, the codebook type corresponding to the main PUCCH group is set to semi-static or dynamic via the RRC information element "pdsch-HARQ-ACK-Codebook" notified from base station 10. Additionally, the parameter names in this embodiment are not limited to those described and may be other names.

[0100] (HARQ-ACK codebook)

[0101] Furthermore, in the following embodiments, an example of SLHARQ-ACK transmission from terminal 20 to base station 10 using a HARQ-ACK codebook is described. Therefore, firstly, an overview of the HARQ-ACK codebook corresponding to DL transmission will be explained. When generating a HARQ-ACK codebook related to SL HARQ-ACK transmission, the downlink can be replaced by a sidelink.

[0102] When transmitting multiple HARQ-ACKs by multiplexing and summarizing them, the HARQ-ACK codebook specifies the summarization method. The HARQ-ACK codebook can be structured to include bits for HARQ-ACK in units of at least one of the following: time domain (e.g., time slot), frequency domain (e.g., component carrier (CC)), spatial domain (e.g., layer, transport block (TB)), and groups of code blocks constituting the TB (code block group (CBG)). Additionally, CC is also referred to as cell, serving cell, carrier, etc. Furthermore, this bit is also referred to as HARQ-ACK bit, HARQ-ACK information, or HARQ-ACK information bit, etc. The HARQ-ACK codebook is also referred to as PDSCH-HARQ-ACK codebook (pdsch-HARQ-ACK-Codebook), codebook, HARQ codebook, HARQ-ACK size, etc.

[0103] The number of bits (size) and other parameters contained in a HARQ-ACK codebook can be determined semi-statically or dynamically. A semi-static HARQ-ACK codebook is also known as a Type I HARQ-ACK codebook or a semi-static codebook. A dynamic HARQ-ACK codebook is also known as a Type II HARQ-ACK codebook or a dynamic codebook.

[0104] The choice of which codebook to use, either Type I HARQ-ACK or Type II HARQ-ACK, can be set for terminal 20 via higher-level parameters (e.g., pdsch-HARQ-ACK-Codebook).

[0105] When using a Type I HARQ-ACK codebook, terminal 20 can feed back HARQ-ACK bits corresponding to a predetermined range (e.g., a range set based on higher-layer parameters) regardless of the presence or absence of PDSCH scheduling.

[0106] The predetermined range can be determined based on at least one of the following: a predetermined period (e.g., a predetermined number of occasions for candidate PDSCH reception, or a predetermined number of monitoring occasions for PDCCH), the number of CCs set or activated in terminal 20, the number of TBs (layers or ranks), the number of CBGs per 1TB, and the presence or absence of space-bundled applications. This predetermined range is also referred to as the HARQ-ACK bundling window, HARQ-ACK feedback window, bundling window, feedback window, etc.

[0107] In the Type I HARQ-ACK codebook, terminal 20 will feed back NACK bits as long as it is within a predetermined range, even without scheduling of PDSCH for terminal 20. Therefore, when using the Type I HARQ-ACK codebook, it is envisioned that the number of HARQ-ACK bits to be fed back will increase.

[0108] On the other hand, when using a Type II HARQ-ACK codebook, the terminal 20 feeds back the HARQ-ACK bits for the scheduled PDSCH within the aforementioned predetermined range.

[0109] Specifically, terminal 20 can determine the number of bits in the Type II HARQ-ACK codebook based on a predetermined field within the DCI (e.g., the DL Assignment Indicator (Index) (DAI) field). The DAI field can be split into counter DAI (counter DAI (cDAI)) and total DAI (total DAI (tDAI)).

[0110] The counter DAI can also represent the count of downlink transmissions (PDSCH, data, TB) scheduled within a predetermined period. For example, the counter DAI within the DCI that schedules data within the predetermined period can also represent the number initially counted in the frequency domain (e.g., CC) and then in the time domain within that predetermined period.

[0111] Total DAI can also represent the total value (total number) of data scheduled within a predetermined period. For example, the total DAI within the DCI that schedules data in a predetermined time unit (e.g., a PDCCH monitoring opportunity) within that predetermined period can also represent the total number of data scheduled up to that predetermined time unit (also known as a point, time, etc.) within that predetermined period.

[0112] Terminal 20 may also use at least one of the Physical Uplink Control Channel (PUCCH) and the Physical Uplink Shared Channel (PUSCH) to send one or more HARQ-ACK bits determined (generated) based on the HARQ-ACK codebook of type I or type II above.

[0113] When using a Type I HARQ-ACK codebook, terminal 20 generates a number of HARQ-ACK bits corresponding to "the number of candidate PDCCH / PDSCH transmissions that may be sent from base station 10, rather than the number of candidate PDCCH / PDSCH transmissions that actually originate from base station 10." That is, for any opportunity to transmit a PDCCH / PDSCH that may originate from base station 10, terminal 20 transmits HARQ-ACK bits regardless of whether or not a PDCCH / PDSCH is actually transmitted from base station 10. For example, for a PDCCH transmission opportunity from base station 10, if no PDCCH transmission occurs from base station 10, terminal 20 may transmit NACK.

[0114] When using a Type II HARQ-ACK codebook, terminal 20 generates a number of HARQ-ACK bits corresponding to the number of PDCCH / PDSCH signals that are assumed to be actually transmitted from base station 10. Additionally, terminal 20 may not be able to receive PDCCH signals from base station 10; therefore, the number of PDCCH signals transmitted from base station 10 to terminal 20 can be notified by including the DAI in the DCI. For example, as... Figure 14 As shown on the left, even if terminal 20 fails to detect the DL DCI shown by (3,0) among the DL DCIs shown by (1,0), (2,0), (3,0), and (0,0), terminal 20 still detects the DL DCI shown by (2,0) and the DL DCI shown by (0,0). Therefore, it can identify the existence of (3,0) between (2,0) and (0,0) and set the HARQ-ACK bit corresponding to (3,0) to NACK before sending it. In this way, in the case of HARQ-ACK codebook of type II, the number of HARQ-ACK bits sent by terminal 20 can be the same as the number of HARQ-ACK bits envisioned on the base station 10 side.

[0115] Here, use Figure 14 This section describes a specific example of using the HARQ-ACK codebook corresponding to downlink reception. Figure 14 This diagram illustrates an example of a multiplexed HARQ response being reported. In the event of a collision between a PUCCH containing a HARQ-ACK and a PUSCH, the HARQ-ACK may be multiplexed for that PUSCH (depending on the context, the PUSCH may also be discarded in the event of a collision between a PUCCH containing a HARQ-ACK and a PUSCH). The DAI (Downlink Assignment Indicator) is sent in the DCI that schedules the PUSCH, indicating the number of HARQ-ACKs that should be multiplexed for the PUSCH based on the DAI value. The DAI in the DCI that schedules the PUSCH is set to UL-DAI. Additionally, the DAI in the DCI that schedules the PDSCH is set to C-DAI (counter DAI) and / or T-DAI (total DAI). Using DAI, inconsistencies in the number of HARQ-ACK bits can be avoided even in the event of a false detection of the PDCCH. Additionally, C-DAI, UL-DAI, and T-DAI are defined below as values ​​starting from 0 with a remainder of 4, but this definition is only one example, and DAI can also be defined in other ways.

[0116] exist Figure 14 The following example illustrates this: In the DL association set, the PDCCH with (C-DAI, T-DAI) = (0, 0) in the 4th time slot fails to receive. Since the multiplexed HARQ-ACK consists of 8 pairs corresponding to (C-DAI, T-DAI) and (1, 0), (2, 0), (3, 0), (0, 0), (1, 2), (2, 2), (3, 3), and (0, 0), UL-DAI is 8 mod 4 = 0. That is, as shown... Figure 14 As shown, the UL-DAI value included in the DCI for allocating the PUSCH is 0. Since UL-DAI = 0, it differs from the expected UL-DAI value (= 3) based on (C-DAI, T-DAI) = (3, 3) in the last received DCI. Therefore, it can be concluded that terminal 20 failed to receive the PDCCH after the last DCI. That is, although 7 PDCCHs were received due to the failure to receive the PDCCH, terminal 20 can still identify that the number of bits in the HARQ-ACK codebook is 8.

[0117] As mentioned above, when multiple codebook types are set, it is necessary to decide which codebook to use in the HARQ feedback of the side link. Figure 15This is a flowchart illustrating an example of the HARQ-ACK reporting operation in an embodiment of the present invention. In step S501, multiple HARQ-ACK codebook types for DL-HARQ-ACK are set. In the next step S502, terminal 20 determines the HARQ-ACK codebook type for SL-HARQ-ACK. Then, terminal 20 can use the determined HARQ-ACK codebook type to report multiple HARQ-ACKs to base station 10.

[0118] When "pdsch-HARQ-ACK-CodebookList" is configured, in step S502, terminal 20 can report SL-HARQ-ACK to base station 10 using the codebook type based on "pdsch-HARQ-ACK-Codebook". That is, "pdsch-HARQ-ACK-Codebook" can be used to determine the codebook type for DL-HARQ-ACK, or it can be used to determine the codebook type for SL-HARQ-ACK.

[0119] Based on the above actions, the codebook used for SL-HARQ-ACK can be determined without depending on the presence or absence of "pdsch-HARQ-ACK-CodebookList", thereby simplifying the terminal structure.

[0120] Furthermore, if “pdsch-HARQ-ACK-CodebookList” is set, in step S502, terminal 20 can use the codebook type based on “pdsch-HARQ-ACK-CodebookList” to report SL-HARQ-ACK to base station 10.

[0121] For example, you can use the 1st HARQ-ACK codebook type from "pdsch-HARQ-ACK-CodebookList" (with an associated priority index of 0 and a low priority).

[0122] Alternatively, the 2nd HARQ-ACK codebook type (with an associated priority index of 1 and high priority) from "pdsch-HARQ-ACK-CodebookList" can also be used.

[0123] Furthermore, the codebook type can be determined based on the priority reported to base station 10 for SL-HARQ-ACK in the "pdsch-HARQ-ACK-CodebookList". For example, in the priority range of 0-7, with a priority of 0 to X (corresponding to higher priorities), the 2nd HARQ-ACK codebook type can be used. Conversely, in the priority range of 0-7, with a priority of X+1 to 7 (corresponding to lower priorities), the 1st HARQ-ACK codebook type can be used. X or X+1 can be determined based on specific higher-level parameters, such as either "sl-PriorityThreshold" or "sl-PriorityThreshold-UL-URLLC".

[0124] Based on the above actions, the same codebook type used as the HARQ-ACK codebook type actually used for DL-HARQ-ACK can be applied to SL. Furthermore, the optimal codebook type can be applied based on the priority of SL.

[0125] Furthermore, when "pdsch-HARQ-ACK-CodebookList" is set, in step S502, terminal 20 can determine the codebook type without depending on the HARQ-ACK codebook type used for DL-HARQ-ACK or higher-level parameters related to the HARQ-ACK codebook type used for DL-HARQ-ACK, and report SL-HARQ-ACK to base station 10. For example, the specification can specify which codebook type, semi-static or dynamic, should be used. Additionally, the codebook type can be set and determined, for example, by higher-level parameters (e.g., "pssch-HARQ-ACK-Codebook", "pssch-HARQ-ACK-CodebookList") used to determine the HARQ-ACK codebook type used for SL-HARQ-ACK. Furthermore, when multiple codebook types are set by "pssch-HARQ-ACK-CodebookList", the codebook type can be determined in the same way as the method described above for determining the codebook type based on "pdsch-HARQ-ACK-CodebookList".

[0126] Based on the above actions, the HARQ-ACK codebook type used by SL-HARQ-ACK can be flexibly set, without depending on the HARQ-ACK codebook type used by DL-HARQ-ACK.

[0127] Furthermore, when "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup" is configured, in step S502, terminal 20 can report SL-HARQ-ACK to base station 10 using a codebook type based on "pdsch-HARQ-ACK-Codebook". That is, "pdsch-HARQ-ACK-Codebook" can be used to determine the codebook type for SL-HARQ-ACK regardless of the PUCCH group associated with SL.

[0128] Based on the above actions, the codebook used for SL-HARQ-ACK can be determined without depending on the presence or absence of "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup", thereby simplifying the terminal structure.

[0129] Furthermore, when "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup" is configured, in step S502, terminal 20 can report SL-HARQ-ACK to base station 10 using a codebook type based on "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup". That is, "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup" can be used to determine the codebook type used for SL-HARQ-ACK, regardless of the PUCCH group associated with SL.

[0130] Based on the above actions, the codebook used for SL-HARQ-ACK can be determined by prioritizing the additionally set "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup".

[0131] Furthermore, when "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup" is configured, in step S502, terminal 20 can report SL-HARQ-ACK to base station 10 using a codebook type determined by parameters related to the PUCCH group associated with SL. For example, SL-HARQ-ACK can be reported to base station 10 using a codebook type determined by parameters related to the PUCCH group in which terminal 20 sends SL-HARQ-ACK.

[0132] For example, when the PUCCH group that terminal 20 sends SL-HARQ-ACK is the main PUCCH group, that is, when sending PUCCH in the main cell or the main / secondary cell group, the HARQ-ACK codebook type can be determined according to "pdsch-HARQ-ACK-Codebook".

[0133] For example, when the PUCCH group in which terminal 20 sends SL-HARQ-ACK is a secondary PUCCH group, that is, when PUCCH is sent in a secondary cell, the HARQ-ACK codebook type can be determined according to "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup".

[0134] Based on the above actions, the codebook type in the PUCCH group associated with SL can be shared in both the DL-HARQ-ACK codebook and the SL-HARQ-ACK codebook.

[0135] Furthermore, when "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup" is set, in step S502, terminal 20 can determine the codebook type without depending on the HARQ-ACK codebook type used for DL-HARQ-ACK or higher-level parameters related to the HARQ-ACK codebook type used for DL-HARQ-ACK, and report SL-HARQ-ACK to base station 10. For example, the specification can specify which codebook type, semi-static or dynamic, should be used. Additionally, the codebook type can be set and determined, for example, by higher-level parameters (e.g., "pssch-HARQ-ACK-Codebook", "pssch-HARQ-ACK-CodebookList") used to determine the HARQ-ACK codebook type used for SL-HARQ-ACK. Furthermore, when multiple codebook types are set by "pssch-HARQ-ACK-CodebookList", the codebook type can be determined in the same way as the method described above for determining the codebook type based on "pdsch-HARQ-ACK-CodebookList".

[0136] Based on the above actions, the SL-HARQ-ACK codebook type can be flexibly set without depending on the DL-HARQ-ACK codebook type.

[0137] Furthermore, when “pdsch-HARQ-ACK-CodebookList” and “pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup” are set, in step S502, the terminal 20 can determine the SL-HARQ-ACK codebook type by any of the methods described above.

[0138] For example, when “pdsch-HARQ-ACK-CodebookList” is used in the secondary PUCCH group instead of “pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup”, terminal 20 can determine the SL-HARQ-ACK codebook based on “pdsch-HARQ-ACK-CodebookList”. Furthermore, for example, in the method where “pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup” is set, terminal 20 can replace “pdsch-HARQ-ACK-Codebook” with “pdsch-HARQ-ACK-CodebookList”.

[0139] Furthermore, if a separate "pdsch-HARQ-ACK-CodebookList" (e.g., "pdsch-HARQ-ACK-CodebookList-secondaryPUCCHgroup") is set for a secondary PUCCH group, in step S502, the terminal 20 can determine the SL-HARQ-ACK codebook type using any of the methods described above. Additionally, regarding the "pdsch-HARQ-ACK-CodebookList" for the secondary PUCCH group, the first codebook type contained in the RRC information element may correspond to a low priority within the secondary PUCCH group, and the second codebook type may correspond to a high priority within the secondary PUCCH group.

[0140] For example, in the method where terminal 20 is configured with "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup", "pdsch-HARQ-ACK-Codebook" can be replaced with "pdsch-HARQ-ACK-CodebookList". Furthermore, for example, in the method where terminal 20 is configured with "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup", "pdsch-HARQ-ACK-Codebook-secondaryPUCCHgroup" can be replaced with "pdsch-HARQ-ACK-CodebookList-secondaryPUCCHgroup".

[0141] The above embodiments are not limited to V2X terminals, but can also be applied to terminals that perform D2D communication.

[0142] The actions described above can be applied to any of the following scenarios: multicast, unicast, or broadcast.

[0143] In addition, there may be multiple UEs or terminals 20, or they may belong to the same group.

[0144] According to the above embodiments, when the terminal 20 is configured with multiple HARQ-ACK codebooks corresponding to DL reception, it can determine the codebook type used in the reports of multiple SL-HARQ-ACK.

[0145] That is, in direct communication between terminals, multiple HARQ (Hybrid automatic repeat request)-ACK reports can be sent to the base station.

[0146] (Device Structure)

[0147] Next, an example of the functional structure of the base station 10 and terminal 20 performing the processes and actions described above will be explained. The base station 10 and terminal 20 include the functions implemented in the above embodiments. However, the base station 10 and terminal 20 may each have only a portion of the functions described in the embodiments.

[0148] <Base Station 10>

[0149] Figure 16 This is a diagram illustrating an example of the functional structure of base station 10. (As shown...) Figure 16 As shown, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130 and a control unit 140. Figure 16The functional structure shown is only one example. As long as the actions involved in the embodiments of the present invention can be performed, the functional distinctions and names of the functional parts can be arbitrary.

[0150] The transmitting unit 110 includes the function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiving unit 120 includes the function of receiving various signals transmitted from the terminal 20 and obtaining, for example, higher-level information from the received signals. In addition, the transmitting unit 110 has the function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL reference signals, etc. to the terminal 20.

[0151] The setting unit 130 stores preset setting information and various setting information sent to the terminal 20 into a storage device, and reads it from the storage device as needed. The content of the setting information includes, for example, information related to SL communication settings.

[0152] As described in the embodiment, the control unit 140 performs processing related to the settings for SL communication for the terminal 20. Furthermore, the control unit 140 transmits scheduling information for SL and DL communication to the terminal 20 via the transmitting unit 110. Additionally, the control unit 140 receives information related to HARQ responses for SL and DL communication from the terminal 20 via the receiving unit 120. Alternatively, the signal transmission-related functions of the control unit 140 may be included in the transmitting unit 110, and the signal reception-related functions of the control unit 140 may be included in the receiving unit 120.

[0153] Terminal 20

[0154] Figure 17 This is a diagram illustrating an example of the functional structure of terminal 20. (As shown...) Figure 17 As shown, the terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. Figure 17 The functional structure shown is only one example. As long as the actions involved in the embodiments of the present invention can be performed, the functional distinctions and names of the functional parts can be arbitrary.

[0155] The transmitting unit 210 generates a transmission signal based on the transmission data and transmits the transmission signal wirelessly. The receiving unit 220 wirelessly receives various signals and obtains higher-layer signals from the received physical layer signals. Furthermore, the receiving unit 220 has the function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals or reference signals transmitted from the base station 10. Additionally, for example, as D2D communication, the transmitting unit 210 transmits PSCCH (Physical Sidelink Control Channel), PSSCH (Physical Sidelink Shared Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel), etc., to other terminals 20, and the receiving unit 220 receives PSCCH, PSSCH, PSDCH, or PSBCH from other terminals 20.

[0156] The setting unit 230 stores various setting information received by the receiving unit 220 from the base station 10 or the terminal 20 into a storage device, and reads it from the storage device as needed. In addition, the setting unit 230 also stores preset setting information. The content of the setting information includes, for example, information related to D2D communication settings.

[0157] As described in the embodiment, the control unit 240 performs processing related to SL communication and HARQ for SL communication. Furthermore, the control unit 240 sends information to the base station 10 related to HARQ responses for SL communication to other terminals 20 scheduled from the base station 10. Additionally, the control unit 240 can also schedule SL communication for other terminals 20. Alternatively, the signal transmission-related functional units of the control unit 240 can be included in the transmitting unit 210, and the signal reception-related functional units of the control unit 240 can be included in the receiving unit 220.

[0158] (Hardware Structure)

[0159] The block diagram used in the description of the above embodiments ( Figure 16 and Figure 17The diagram illustrates blocks organized by function. These functional blocks (structural units) are implemented through any combination of at least one of hardware and software. Furthermore, there are no particular limitations on the implementation method of each functional block. That is, each functional block can be implemented using a single device that is physically or logically combined, or by directly or indirectly (e.g., using wired, wireless, etc.) connecting two or more physically or logically separate devices. Functional blocks can also be implemented by combining software with one or more of the aforementioned devices.

[0160] Functionally, it includes functions such as judgment, decision, determination, calculation, calculation, processing, derivation, investigation, search, confirmation, receiving, sending, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assigning, but is not limited to these. For example, the functional block (structural part) that enables transmission is called the transmitting unit or transmitter. In short, as mentioned above, there are no particular limitations on the implementation method.

[0161] For example, in one embodiment of this disclosure, the base station 10, terminal 20, etc., can also function as a computer for processing the wireless communication method of this disclosure. Figure 18 This is a diagram illustrating an example of the hardware structure of a base station 10 and a terminal 20 according to an embodiment of the present disclosure. The base station 10 and the terminal 20 described above may also 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.

[0162] Additionally, in the following description, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware structure of base station 10 and terminal 20 can be configured to include one or more of the devices shown in the figures, or it can be configured to not include any of them.

[0163] The functions of the base station 10 and the terminal 20 are implemented by reading predetermined software (programs) into hardware such as the processor 1001 and the storage device 1002, so that the processor 1001 performs calculations and controls the communication of the communication device 1004 or controls at least one of reading out and writing data in the storage device 1002 and the auxiliary storage device 1003.

[0164] The processor 1001 controls the computer as a whole, for example, by enabling the operating system to function. The processor 1001 may also be a central processing unit (CPU) that includes interfaces with peripheral devices, control units, arithmetic units, registers, etc. For example, the aforementioned control unit 140, control unit 240, etc., can also be implemented using the processor 1001.

[0165] Furthermore, the processor 1001 reads programs (program code), software modules, or data from at least one of the auxiliary storage devices 1003 and communication devices 1004, and performs various processes accordingly. As a program, a program is used to cause the computer to perform at least some of the actions described in the above embodiments. For example, Figure 16 The control unit 140 of the base station 10 shown can also be implemented by a control program stored in the storage device 1002 and operating in the processor 1001. Furthermore, for example, Figure 17 The control unit 240 of the terminal 20 shown can also be implemented by a control program stored in the storage device 1002 and operating in the processor 1001. Regarding the various processes described above, although it has been stated that the various processes are executed by one processor 1001, the various processes can also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 can also be installed using more than one chip. Furthermore, the program can also be transmitted from a network via a telecommunications line.

[0166] Storage device 1002 is a computer-readable recording medium, and may be composed of at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. Storage device 1002 may also be referred to as a register, cache, main memory (main storage device), etc. Storage device 1002 can store programs (program code), software modules, etc., that are executable for implementing the communication method according to one embodiment of this disclosure.

[0167] The auxiliary storage device 1003 is a computer-readable recording medium, such as at least one of the following: CD-ROM (CompactDisc ROM), hard disk drive, floppy disk, magneto-optical disk (e.g., compact disk, digital multipurpose disk, Blu-ray disk, smart card, flash memory (e.g., card, stick, key drive), floppy disk, magnetic stripe, etc.). The aforementioned storage medium may be, for example, a database, server, or other suitable media that includes at least one of the storage device 1002 and the auxiliary storage device 1003.

[0168] Communication device 1004 is hardware (transceiver) used for communication between computers via at least one of a wired network and a wireless network. It is also referred to as a network device, network controller, network interface card (NIC), communication module, etc. Communication device 1004 may, for example, be configured to include high-frequency switches, duplexers, filters, frequency synthesizers, etc., to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, transceiver antennas, amplifiers, transceiver units, transmission path interfaces, etc., can also be implemented using communication device 1004. The transceiver unit may also be physically or logically separated into a transmitting unit and a receiving unit.

[0169] Input device 1005 is an input device that accepts input from external sources (e.g., keyboard, mouse, microphone, switch, button, sensor, etc.). Output device 1006 is an output device that performs output to external sources (e.g., display, speaker, LED, etc.). Alternatively, input device 1005 and output device 1006 can also be integrated (e.g., a touch panel).

[0170] Furthermore, the processor 1001 and storage device 1002, among other devices, are connected via a bus 1007 for communicating information. The bus 1007 can be a single bus or can be composed of different buses between devices.

[0171] Furthermore, the base station 10 and the terminal 20 can be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or a FPGA (Field Programmable Gate Array), and can also use this hardware to implement part or all of the functional blocks. For example, the processor 1001 can also be implemented using at least one of these hardware components.

[0172] (Summary of Implementation Methods)

[0173] As explained above, according to an embodiment of the present invention, a terminal is provided, comprising: a receiving unit that receives one or more pieces of information from a base station, the one or more pieces of information specifying a plurality of codebooks, the plurality of codebooks being used to send a response related to retransmission control applied to transmission and reception in a downlink; a control unit that determines one of the plurality of codebooks for sending a response related to retransmission control applied to transmission and reception in a sidelink; and a sending unit that uses the determined codebook to send one or more responses related to retransmission control applied to transmission and reception in a sidelink to the base station.

[0174] Based on the above structure, when terminal 20 is configured with multiple HARQ-ACK codebooks corresponding to DL reception, it can determine the codebook type used in the reports of multiple SL-HARQ-ACKs. That is, in direct communication between terminals, it can report multiple HARQ (Hybrid automatic repeat request)-ACKs to the base station.

[0175] The information specifying the multiple codebooks may also include an associated first codebook with lower priority and an associated second codebook with higher priority. According to this structure, when multiple HARQ-ACK codebooks corresponding to DL reception are configured, terminal 20 can determine the codebook type used in the reports of multiple SL-HARQ-ACKs based on priority.

[0176] The control unit can also determine the first codebook when the priority associated with transmission and reception in the side link is low, and determine the second codebook when the priority associated with transmission and reception in the side link is high. According to this structure, when multiple HARQ-ACK codebooks corresponding to DL reception are set, the terminal 20 can determine the codebook type used in the reports of multiple SL-HARQ-ACK according to the priority.

[0177] The information specifying the multiple codebooks may also include a first codebook applied to the primary PUCCH (Physical uplink control channel) group and a second codebook applied to the secondary PUCCH group. Based on the above structure, when multiple HARQ-ACK codebooks corresponding to DL reception are configured, terminal 20 can determine the codebook type used in the reports of multiple SL-HARQ-ACKs.

[0178] The control unit can also determine the first codebook or the second codebook corresponding to the PUCCH group that sends the one or more responses. Based on the above structure, when multiple HARQ-ACK codebooks corresponding to DL reception are set, the terminal 20 can determine the codebook type used in the reports of multiple SL-HARQ-ACKs based on the PUCCH group that sends the report.

[0179] Furthermore, according to an embodiment of the present invention, a communication method is provided, comprising the following steps: a receiving step, receiving one or more pieces of information from a base station, wherein the one or more pieces of information specify multiple codebooks, the multiple codebooks being used to send a response related to retransmission control applied to transmission and reception in the downlink; a controlling step, determining one of the multiple codebooks for sending a response related to retransmission control applied to transmission and reception in the sidelink; and a sending step, using the determined codebook, sending one or more responses related to retransmission control applied to transmission and reception in the sidelink to the base station.

[0180] Based on the above structure, when terminal 20 is configured with multiple HARQ-ACK codebooks corresponding to DL reception, it can determine the codebook type used in the reports of multiple SL-HARQ-ACKs. That is, in direct communication between terminals, it can report multiple HARQ (Hybrid automatic repeat request)-ACKs to the base station.

[0181] (Supplement to the implementation method)

[0182] The embodiments of the present invention have been described above, but the disclosed invention is not limited to such embodiments. Those skilled in the art should understand various modifications, alterations, substitutions, and replacements. Specific numerical examples have been used to facilitate understanding of the invention, but unless otherwise specified, these values ​​are merely examples, and any appropriate values ​​may be used. The distinctions between items in the above description are not essential to the present invention; items described in two or more items may be combined as needed, and items described in one item may be applied to items described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical components. Physically, one component may perform the operation of multiple functional units, or multiple components may perform the operation of one functional unit. Regarding the processing described in the embodiments, the order of processing may be interchanged unless there is a contradiction. For ease of explanation, the base station 10 and terminal 20 have been described using functional block diagrams, but such a device may also be implemented in hardware, software, or a combination thereof. The software operating via the processor of the base station 10 according to an embodiment of the present invention and the software operating via the processor of the terminal 20 according to an embodiment of the present invention can also be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server and other suitable storage media, respectively.

[0183] Furthermore, the notification of information is not limited to the forms / implementations described in this disclosure, and other methods may also be used. For example, information notification may be implemented through physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof. Additionally, RRC signaling may also be referred to as an RRC message, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, etc.

[0184] The various forms / implementations described in this disclosure can also be applied to at least one of LTE (Long Term Evolution), LTE-A (LTE-Advanced), 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-Wide Band), Bluetooth (registered trademark), systems using other suitable systems, and next-generation systems extended therefrom. Furthermore, multiple systems can be combined (e.g., a combination of at least one of LTE and LTE-A with 5G, etc.) for application.

[0185] The processing procedures, timing, and flow of the various forms / implementations described in this specification may be rearranged in order, provided there is no contradiction. For example, the elements of various steps are indicated using an illustrative order for the methods described in this disclosure, but are not limited to the specific order indicated.

[0186] In this specification, certain actions purported to be performed by base station 10 may sometimes be performed through its upper node, depending on the circumstances. In a network consisting of one or more network nodes including base station 10, it is obvious that various actions performed to communicate with terminal 20 can be performed by at least one of base station 10 and other network nodes besides base station 10 (e.g., considering MME or S-GW, but not limited to these). The above example illustrates the case where there is only one other network node besides base station 10, but other network nodes can also be a combination of multiple other network nodes (e.g., MME and S-GW).

[0187] It can output information or signals described in this disclosure from a higher (or lower) layer to a lower (or higher) layer. It can also be input or output via multiple network nodes.

[0188] Input or output information can be stored in a specific location (e.g., memory) or managed using a management table. Input or output information can be overwritten, updated, or appended. Output information can also be deleted. Input information can also be sent to other devices.

[0189] The determination in this disclosure can be made by a value represented by 1 bit (0 or 1), by a Boolean value (Boolean: true or false), or by a comparison of numerical values ​​(e.g., a comparison with a predetermined value).

[0190] Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or by other names, should be broadly interpreted as commands, command sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc.

[0191] Furthermore, software, commands, and information can be sent and received via a transmission medium. For example, when software is sent from a website, server, or other remote source using at least one of wired technologies (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technologies (infrared, microwave, etc.), at least one of these wired and wireless technologies is included within the definition of a transmission medium.

[0192] The information, signals, etc., described in this disclosure can also be represented using any of a variety of different technologies. For example, the data, commands, instructions, information, signals, bits, symbols, chips, etc., that may be involved in the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination of these.

[0193] Furthermore, the terms used in this disclosure and those necessary for understanding this disclosure may be replaced with terms that have the same or similar meanings. For example, at least one of the channel and symbol may also be a signal (signaling). Additionally, a signal may also be a message. Furthermore, a component carrier (CC) may also be referred to as a carrier frequency, cell, frequency carrier, etc.

[0194] The terms “system” and “network” as used in this disclosure are used interchangeably.

[0195] Furthermore, the information, parameters, etc., described in this disclosure may be represented using absolute values, relative values ​​to predetermined values, or other corresponding information. For example, wireless resources may also be indicated by indexes.

[0196] The names used for the above parameters are not limiting in any way. Furthermore, the formulas, etc., using these parameters sometimes differ from those explicitly disclosed in this disclosure. Since various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by all appropriate names, the various names assigned to these various channels and information elements are not limiting in any way.

[0197] In this disclosure, the terms "base station (BS)," "wireless 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" are used interchangeably. Sometimes, terms such as macro cell, small cell, femtocell, and picocell are also used to refer to base stations.

[0198] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, its coverage area can be divided into several smaller areas, each of which can also provide communication services through a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). Terms such as "cell" or "sector" refer to a portion or all of the coverage area of ​​at least one of the base station and base station subsystem providing communication services within that coverage area.

[0199] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" are used interchangeably.

[0200] For mobile stations, those skilled in the art sometimes also use the following terms: 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, handheld device, user agent, mobile client, client, or some other appropriate terms.

[0201] At least one of the base station and the mobile station can be referred to as a transmitting device, a receiving device, a communication device, etc. Additionally, at least one of the base station and the mobile station can also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body can be a vehicle (e.g., a car, an airplane, etc.), a mobile body moving in an unmanned manner (e.g., a drone, an autonomous vehicle, etc.), or a robot (humanized or unmanned). Furthermore, at least one of the base station and the mobile station also includes devices that do not necessarily move during communication. For example, at least one of the base station and the mobile station can be an IoT (Internet of Things) device such as a sensor.

[0202] Furthermore, the base station in this disclosure can also be replaced by a user terminal. For example, various forms / implementations of this disclosure can be applied to a structure that replaces the communication between the base station and the user terminal with communication between multiple terminals 20 (e.g., also referred to as D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). In this case, the terminal 20 can also be configured to have the functions of the base station 10 described above. In addition, terms such as "uplink" and "downlink" can be replaced with terms corresponding to communication between terminals (e.g., "side"). For example, uplink channel, downlink channel, etc., can also be replaced with side channel.

[0203] Similarly, the user terminal in this disclosure can be replaced by a base station. In this case, the base station can also be configured to have the functions of the user terminal described above.

[0204] The terms "determining" and "determining" as used in this disclosure sometimes encompass a variety of actions. For example, "determining" and "determining" can include actions such as judging, calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, database, or other data structure), and ascertaining, which are considered as actions of "determining" and "determining." Furthermore, "determining" and "determining" can include actions such as receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, and accessing (e.g., accessing data in memory), which are considered as actions of "determining" and "determining." Additionally, "determining" and "determining" can include actions such as resolving, selecting, choosing, establishing, and comparing, which are considered as actions of "determining" and "determining." That is, "judgment" and "decision" can include matters that are considered to have been "judged" or "decided" to take any action. In addition, "judgment (decision)" can also be replaced by "assuming", "expecting", "considering", etc.

[0205] The terms “connected,” “coupled,” or any variations thereof are intended to indicate any direct or indirect connection or combination between two or more elements, including cases where there is one or more intermediate elements between the two elements that are “connected” or “coupled.” The combination or connection between elements can be physical, logical, or a combination of these. For example, “access” can be used instead of “connected.” In the context of this disclosure, it can be understood that two elements are “connected” or “coupled” to each other using at least one of one or more wires, cables, and printed electrical connections, and, as some non-limiting and non-inclusive examples, using electromagnetic energy with wavelengths in the wireless frequency domain, microwave region, and light (both visible and invisible) region to “connect” or “couple” to each other.

[0206] The reference signal can be simply referred to as RS (Reference Signal), or, depending on the standard applied, as a pilot.

[0207] As used in this disclosure, the word "based on" does not mean "based on only" unless otherwise expressly stated. In other words, the word "based on" means both "based on only" and "based on at least" both.

[0208] Any reference to elements using the designations "first," "second," etc., as used in this disclosure does not necessarily limit the number or order of these elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Therefore, references to the first element and the second element do not imply that only two elements can be taken or that in any form the first element must precede the second element.

[0209] Alternatively, the term "unit" in the structure of the above devices can be replaced with "section," "circuit," "equipment," etc.

[0210] When the terms "include," "including," and their variations are used in this disclosure, these terms, like the term "comprising," imply inclusion. Furthermore, the term "or" as used in this disclosure implies non-exclusivity.

[0211] A radio frame can consist of one or more frames in the time domain. Each frame in the time domain can be called a subframe. A subframe can further consist of one or more time slots in the time domain. A subframe can also be a fixed time length (e.g., 1 ms) independent of the parameter set (numerology).

[0212] A parameter set can be communication parameters applied to at least one side of the transmission and reception of a signal or channel. For example, a parameter set can represent at least one of the following: Subcarrier Spacing (SCS), bandwidth, symbol length, cyclic prefix length, Transmission Time Interval (TTI), number of symbols per TTI, radio frame structure, specific filtering processing performed by the transceiver in the frequency domain, and specific windowing processing performed by the transceiver in the time domain.

[0213] In the time domain, a time slot can be composed of one or more symbols (OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.). A time slot can be a time unit based on a set of parameters.

[0214] A time slot can contain multiple mini-time slots. Each mini-time slot can consist of one or more symbols in the time domain. Furthermore, a mini-time slot can also be called a sub-time slot. A mini-time slot can consist of fewer symbols than a time slot. PDSCH (or PUSCH) transmitted in time units larger than mini-time slots can be called PDSCH (or PUSCH) mapping type (type) A. PDSCH (or PUSCH) transmitted using mini-time slots can be called PDSCH (or PUSCH) mapping type (type) B.

[0215] Radio frames, subframes, time slots, mini-time slots, and symbols all represent time units for transmitting signals. Radio frames, subframes, time slots, mini-time slots, and symbols can each be referred to by other corresponding names.

[0216] For example, a subframe can also be called a Transmission Time Interval (TTI), multiple consecutive subframes can also be called a TTI, a time slot or a mini-time slot can also be called a TTI. That is, at least one of a subframe and a TTI can be a subframe in existing LTE (1ms), a period shorter than 1ms (e.g., symbols 1-13), or a period longer than 1ms. In addition, the unit representing TTI may not be called a subframe, but rather a time slot, mini-time slot, etc.

[0217] Here, TTI refers, for example, to the smallest unit of time for scheduling in wireless communication. For instance, in an LTE system, the base station schedules the allocation of radio resources (bandwidth, transmit power, etc., available to each terminal 20) on a TTI basis. However, the definition of TTI is not limited to this.

[0218] The Time Interval (TTI) can be the transmission time unit for channel-coded data packets (transmission blocks), code blocks, codewords, etc., or it can be a processing unit for scheduling, link adaptation, etc. Furthermore, when a TTI is given, the actual time interval (e.g., the number of symbols) in which the transmission block, code block, codeword, etc., are mapped can be shorter than that TTI.

[0219] Furthermore, when one time slot or one mini-time slot is referred to as a TTI, more than one TTI (i.e., more than one time slot or more than one mini-time slot) can constitute the minimum time unit for scheduling. Moreover, the number of time slots constituting this minimum time unit for scheduling (the number of mini-time slots) can be controlled.

[0220] A TTI with a duration of 1ms can also be referred to as a normal TTI (TTI in LTE Rel.8-12), a long TTI, a normal subframe, a long subframe, or a time slot. A TTI shorter than a normal TTI can also be referred to as a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini time slot, a sub-time slot, or a time slot.

[0221] Additionally, for long TTIs (e.g., regular TTIs, subframes, etc.), they can be replaced with TTIs with a duration of more than 1ms. For short TTIs (e.g., shortened TTIs, etc.), they can be replaced with TTIs with a duration of less than long TTIs and a duration of more than 1ms.

[0222] A resource block (RB) is a unit of resource allocation in both the time and frequency domains. In the frequency domain, it can contain one or more consecutive subcarriers. The number of subcarriers contained in an RB can be the same regardless of the parameter set; for example, it can be 12. The number of subcarriers contained in an RB can also be determined based on the parameter set.

[0223] Furthermore, the time domain of an RB can contain one or more symbols, and can also be one time slot, one mini-time slot, one subframe, or one TTI in length. One TTI, one subframe, etc., can each be composed of one or more resource blocks.

[0224] In addition, one or more RBs can be called Physical Resource Block (PRB), Sub-Carrier Group (SCG), Resource Element Group (REG), PRB Pair, RB Pair, etc.

[0225] Furthermore, a resource block can consist of one or more resource elements (REs). For example, 1 RE can be a radio resource area with 1 subcarrier and 1 symbol.

[0226] The Bandwidth Part (BWP) (which may be referred to as the bandwidth portion, etc.) can represent a contiguous subset of common resource blocks (RBs) used for a certain parameter set in a given carrier. Here, common resource blocks can be determined by indexing RBs based on a common reference point of that carrier. PRBs can be defined and numbered within a BWP.

[0227] A BWP can include a UL BWP and a DL BWP. One or more BWPs can be configured for terminal 20 within one carrier.

[0228] At least one of the configured BWPs can be active, and it is not assumed that the terminal 20 will transmit or receive predetermined signals / channels outside of an active BWP. Furthermore, the terms "cell," "carrier," etc., used in this disclosure can be replaced with "BWP."

[0229] The structures of radio frames, subframes, time slots, mini-time slots, and symbols described above are merely illustrative. For example, the number of subframes contained in a radio frame, the number of time slots in each subframe or radio frame, the number of mini-time slots contained in a time slot, the number of symbols and RBs contained in a time slot or mini-time slot, the number of subcarriers contained in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc., can be varied in many ways.

[0230] In this disclosure, for example, in cases where articles are added through translation, such as in English (e.g., a, an, and the), this disclosure may also include cases where the noun following these articles is in a plural form.

[0231] In this disclosure, the phrase "A is different from B" can also mean "A and B are not the same." Furthermore, this phrase can also mean "A and B are each different from C." Terms such as "separate" and "combined" can also be interpreted in the same way as "different."

[0232] The various forms / implementations described in this disclosure can be used individually or in combination, and can be switched depending on the execution. Furthermore, the notification of predetermined information is not limited to explicit notification (e.g., a "Yes X" notification) but can also be implicit notification (e.g., not notifying the predetermined information).

[0233] Additionally, in this disclosure, HARQ-ACK is an example of a response related to retransmission control.

[0234] The present disclosure has been described in detail above, but it will be 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 as modifications and variations without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the present disclosure is for illustrative purposes only and is not intended to be limiting.

[0235] Label Explanation

[0236] 10: Base station;

[0237] 110: Dispatch Department;

[0238] 120: Receiving Unit;

[0239] 130: Setting Department;

[0240] 140: Control Department;

[0241] 20: Terminal;

[0242] 210: Sending Department;

[0243] 220: Receiving unit;

[0244] 230: Setting Department;

[0245] 240: Control Unit;

[0246] 1001: Processor;

[0247] 1002: Storage device;

[0248] 1003: Auxiliary storage device;

[0249] 1004: Communication devices;

[0250] 1005: Input device;

[0251] 1006: Output device.

Claims

1. A terminal, wherein, The terminal has: a reception section that receives first RRC information and second RRC information from a base station, the first RRC information relating to one codebook for response involved in retransmission control applied in transceiving of a downlink, the second RRC information relating to at most two codebooks for response involved in retransmission control applied in transceiving of a downlink; and a transmission section that transmits, to the base station, response involved in retransmission control applied in transceiving of a sidelink using a codebook of a type decided based on the first RRC information, in a case where the second RRC information is set.

2. The terminal according to claim 1, wherein the transmission section transmits, to the base station, response involved in retransmission control applied in transceiving of a downlink using a codebook of a type decided based on the second RRC information, in a case where the second RRC information is set.

3. A terminal, wherein, The terminal has: a reception section that receives first RRC information and third RRC information from a base station, the first RRC information relating to one codebook for response involved in retransmission control applied in transceiving of a downlink, the third RRC information relating to a codebook for response involved in retransmission control applied in transceiving of a downlink, which is directed to a secondary physical uplink control channel group (secondary PUCCH group); a transmission section that transmits, to the base station, response involved in retransmission control applied in transceiving of a sidelink using a codebook of a type decided based on the first RRC information, in a case where the third RRC information is set.

4. The terminal according to claim 3, wherein the transmission section transmits, to the base station, response involved in retransmission control applied in transceiving of a downlink, which is directed to a secondary PUCCH group, using a codebook of a type decided based on the third RRC information, and transmits, to the base station, response involved in retransmission control applied in transceiving of a downlink, which is directed to a primary PUCCH group, using a codebook of a type decided based on the first RRC information, in a case where the third RRC information is set.

5. A base station, wherein, The base station has: a transmission section that transmits first RRC information and second RRC information to a terminal, the first RRC information relating to one codebook for response involved in retransmission control applied in transceiving of a downlink, the second RRC information relating to at most two codebooks for response involved in retransmission control applied in transceiving of a downlink; and a reception section that receives, from the terminal, response involved in retransmission control applied in transceiving of a sidelink using a codebook of a type decided based on the first RRC information, in a case where the second RRC information is set.

6. A communication system including a terminal and a base station, wherein the terminal has: a reception section that receives first RRC information and second RRC information from the base station, the first RRC information relating to one codebook for response involved in retransmission control applied in transceiving of downlink, the second RRC information relating to at most two codebooks for response involved in retransmission control applied in transceiving of downlink; a transmission section that transmits, to the base station, response involved in retransmission control applied in transceiving of sidelink using a codebook of a type decided based on the first RRC information in a case where the second RRC information is set, the base station has: a transmission section that transmits the first RRC information and the second RRC information to the terminal; and a reception section that receives, from the terminal, response involved in retransmission control applied in transceiving of sidelink using a codebook of a type decided based on the first RRC information in a case where the second RRC information is set.

7. A communication method, wherein, The following steps are performed by a terminal: receiving first RRC information and second RRC information from a base station, the first RRC information relating to one codebook for response involved in retransmission control applied in transceiving of downlink, the second RRC information relating to at most two codebooks for response involved in retransmission control applied in transceiving of downlink; and transmitting, to the base station, response involved in retransmission control applied in transceiving of sidelink using a codebook of a type decided based on the first RRC information in a case where the second RRC information is set.

Images