Method, apparatus, and system for generating a HARQ-ACK codebook in a wireless communication system

Abstract

One aspect of the present invention discloses a terminal of a wireless communication system. The terminal includes a communication module and a processor for controlling the communication module. Wherein, the processor generates a Hybrid Automatic Repeat reQuest (HARQ)-ACK codebook, which includes one or more bits indicating whether the reception of a channel or a signal is successful. The processor further sends the HARQ-ACK codebook to a base station of the wireless communication system. Wherein, the HARQ-ACK codebook is generated based on time slots corresponding to values of HARQ-ACK feedback timing parameters (K1) set at a sub-slot level, and each bit of the configured HARQ-ACK codebook corresponds to at least one sub-slot among a plurality of sub-slots included in the time slot.

Description

Technical Field

[0001] The present invention relates to a wireless communication system, and more particularly, to a method for generating a HARQ-ACK codebook of a wireless communication system and an apparatus using the method. Background Art

[0002] After the commercialization of the fourth-generation (4G) communication system, in order to meet the increasing demand for wireless data services, efforts are being made to develop a new fifth-generation (5G) communication system. The 5G communication system is referred to as a super 4G network communication system, a post-LTE system, or a new radio (NR) system. To achieve high data transmission rates, the 5G communication system includes systems that operate using millimeter wave (mmWave) frequencies of 6 GHz or higher, and in terms of ensuring coverage, includes communication systems that operate using frequencies of 6 GHz or lower, such that implementation methods in base stations and terminals are under consideration.

[0003] The Third Generation Partnership Project (3GPP) NR system improves the spectral efficiency of the network and enables communication providers to provide more data and voice services on a given bandwidth. Therefore, the 3GPP NR system is designed to meet the requirements for high-speed data and media transmission in addition to supporting a large number of voice calls. The advantages of the NR system are higher throughput and lower latency on the same platform, support for frequency division duplexing (FDD) and time division duplexing (TDD), and low operating costs due to an enhanced end-user environment and a simple architecture.

[0004] For more efficient data processing, the dynamic TDD of the NR system can use a method for changing the number of orthogonal frequency division multiplexing (OFDM) symbols that can be used in the uplink and downlink according to the data traffic direction of the cell users. For example, when the downlink traffic of the cell is greater than the uplink traffic, the base station can allocate multiple downlink OFDM symbols to a time slot (or subframe). Information about the time slot configuration should be sent to the terminal.

[0005] In order to mitigate the path loss of radio waves and increase the transmission distance of radio waves in the mmWave band, in the 5G communication system, beamforming, massive multiple-input / multiple-output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, hybrid beamforming that combines analog beamforming and digital beamforming, and massive antenna technology have been discussed. In addition, for network improvement of the system, in the 5G communication system, technology development related to evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network, device-to-device communication (D2D), vehicle-to-everything communication (V2X), wireless backhaul, non-terrestrial network communication (NTN), mobile network, cooperative communication, coordinated multi-point (CoMP), interference cancellation, etc. is underway. In addition, in the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superimposed coding (SWSC) as advanced coding modulation (ACM) schemes, and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced connection technologies are being developed.

[0006] Meanwhile, in a human-centric connected network where humans generate and consume information, the Internet has evolved into an Internet of Things (IoT) network that exchanges information between distributed components such as objects. The Internet of Everything (IoE) technology that combines IoT technology with big data processing technology through connection to a cloud server is also emerging. To implement IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, so in recent years, technologies such as sensor networks, machine-to-machine (M2M), and machine type communication (MTC) have been studied to connect between objects. In the IoT environment, intelligent Internet technology (IT) services can be provided that collect and analyze data generated from connected objects to create new value in human life. Through the integration and hybridization of existing information technology (IT) and various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services.

[0007] Therefore, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine type communication (MTC) are implemented through technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN as the above-mentioned big data processing technology is an example of the integration of 5G technology and IoT technology. Generally, mobile communication systems are developed to provide voice services while ensuring the activities of users.

[0008] However, the field of mobile communication systems has expanded not only to voice services but also to data services, and has now evolved to provide high-speed data services. However, in the current mobile communication systems used to provide services, resource shortages have occurred, and users need faster services, and thus more advanced wireless communication systems are required. Summary of the Invention

[0009] Technical Problem

[0010] An object of an embodiment of the present invention is to provide a method and apparatus for efficiently generating a HARQ-ACK codebook in a wireless communication system.

[0011] Technical Solution

[0012] To achieve the above object, according to an aspect of the present invention, a user equipment (UE) of a wireless communication system includes: a communication module; and a processor for controlling the communication module, wherein the processor generates a hybrid automatic repeat request (HARQ)-ACK codebook, the HARQ-ACK codebook includes at least one bit indicating whether a channel or a signal has been successfully received, and transmits the HARQ-ACK codebook to a base station of the wireless communication system, wherein the HARQ-ACK codebook is generated based on a time slot corresponding to a HARQ-ACK feedback timing parameter (K1) value configured at a sub-time slot level, and each bit constituting the HARQ-ACK codebook corresponds to at least one sub-time slot among a plurality of sub-time slots included in the time slot.

[0013] The processor may convert the K1 value configured at a sub-time slot level into a K1 value configured at a time slot level, wherein the time slot may be determined by a time slot level HARQ-ACK feedback timing value.

[0014] The K1 value configured at a sub-time slot level may be converted into a K1 value configured at a time slot level K through the following equation 1,k,slot , where K 1,k may represent the K1 value configured at a sub-time slot level, k may represent an index of the K1 value configured at a sub-time slot level, K 1,k,slot may represent the K1 value configured at a time slot level, n U may represent an index of a sub-time slot in which a physical uplink control channel (PUCCH) is transmitted, N may represent the number of sub-time slots in a time slot, and may represent the largest integer among numbers equal to or less than x.

[0015]

[0016] The processor may use K 1,k,slot to determine the validity of at least one physical downlink shared channel (PDSCH) candidate for a separate time slot.

[0017] The processor can determine the validity of individual PDSCH candidates by determining at least one PDSCH candidate for each start and length indicator value (SLIV).

[0018] The processor can determine the validity of the PDSCH candidates for the corresponding downlink time slot according to the descending order of K 1,k .

[0019] The processor can determine the validity of at least one PDSCH candidate for each of the at least one PDSCH candidates based on whether the last symbol is included in the first sub-slot.

[0020] (i) It can determine that the PDSCH candidate is valid according to the last symbol of the PDSCH candidate being included in the first sub-slot, and (ii) it can determine that the PDSCH candidate is invalid according to the last symbol of the PDSCH candidate not being included in the first sub-slot.

[0021] The first sub-slot can correspond to the value obtained by subtracting the K1 value K at the sub-slot level from the sub-slot n in which the PUCCH is transmitted U . 1,k

[0022] When the processor does not have the ability to receive multiple PDSCHs in one time slot, it can include one HARQ-ACK bit in the HARQ-ACK codebook for the first downlink time slot corresponding to K 1,k .

[0023] When the first PDSCH candidate and the second PDSCH candidate after the first PDSCH candidate are valid in the first downlink time slot, it can be determined that the HARQ-ACK bit for the second PDSCH candidate is not included in the HARQ-ACK codebook according to the HARQ-ACK bit for the first downlink time slot used by the first PDSCH candidate being included in the HARQ-ACK codebook.

[0024] When receiving a PDSCH in one of the first PDSCH candidate and the second PDSCH candidate, the processor can send the HARQ-ACK information of the PDSCH at the HARQ-ACK bit at the position corresponding to the first downlink time slot in the HARQ-ACK codebook.

[0025] The processor can calculate all the K1 values configured at the sub-slot level corresponding to the K1 value converted to the time slot level, and determine the validity of at least one PDSCH candidate based on all the calculated K1 values configured at the sub-slot level.

[0026] ​The processor may calculate a set of K1 values at the slot level based on a set of multiple K1 values configured at the sub-slot level, and generate a HARQ-ACK codebook by determining the validity of at least one PDSCH candidate for a corresponding downlink slot according to the descending order of the K1 values at the slot level configured based on the calculated K1 values at the slot level.

[0027] The processor (i) may determine the validity of a PDSCH candidate for a downlink slot corresponding to a first slot-level K1 value, and (ii) subsequently, may determine the validity of a PDSCH candidate for a DL slot corresponding to a second slot-level K1 value smaller than the first slot-level K1 value.

[0028] Based on whether the last symbol of a first PDSCH candidate in a first downlink slot corresponding to a first slot-level K1 value is included in a second sub-slot calculated using the first slot-level K1 value, the processor may determine the validity of the first PDSCH candidate.

[0029] The processor may determine that a PDSCH candidate is valid according to the last symbol of the PDSCH candidate being included in at least one of the second sub-slots, and determine that the PDSCH candidate is invalid according to the last symbol of the PDSCH candidate not being included in the second sub-slots.

[0030] The second sub-slot may correspond to a value obtained by subtracting at least one K1 value configured at the sub-slot level corresponding to the first slot-level K1 value from the sub-slot n in which the PUCCH is transmitted U minus the at least one K1 value configured at the sub-slot level corresponding to the first slot-level K1 value.

[0031] The HARQ-ACK codebook may be a semi-static HARQ-ACK codebook, which is configured based on radio resource control (RRC) signaling to indicate the number of bits of the HARQ-ACK codebook and which channel or signal each bit of the HARQ-ACK codebook indicates the reception success / failure of.

[0032] To achieve the above object, according to another aspect of the present invention, a method for operating a user equipment (UE) of a wireless communication system includes the following steps: generating a hybrid automatic repeat request (HARQ)-ACK codebook, the HARQ-ACK codebook including at least one bit indicating whether a channel or signal has been successfully received; and transmitting the HARQ-ACK codebook to a base station of the wireless communication system, wherein the step of generating the HARQ-ACK codebook includes the following steps: generating the HARQ-ACK codebook based on a slot corresponding to a HARQ-ACK feedback timing parameter (K1) value configured at the sub-slot level.

[0033] The steps for generating a HARQ-ACK codebook may include the following steps: converting the value of the HARQ-ACK feedback timing parameter (K1) configured at the sub-slot level into a HARQ-ACK feedback timing value at the sub-slot level, and determining a sub-slot through the HARQ-ACK feedback timing value at the sub-slot level.

[0034] The steps for generating a HARQ-ACK codebook may include: using the converted K1 value K at the sub-slot level 1,k,slot , to determine the validity of at least one physical downlink shared channel (PDSCH) candidate for a separate sub-slot.

[0035] The steps for generating a HARQ-ACK codebook may include the following steps: for each of at least one PDSCH candidate, determining the validity of the at least one PDSCH candidate based on whether the last symbol is included in the first sub-slot.

[0036] Advantageous Effects

[0037] According to an embodiment of the present invention, a UE may transmit a PUCCH including two or more HARQ-ACKs in one sub-slot, and at this time, the coverage range of the PUCCH may be increased by reducing the amount of HARQ-ACK that each PUCCH may have. Brief Description of the Drawings

[0038] Figure 1 Illustrates an example of a radio frame structure used in a wireless communication system.

[0039] Figure 2 Illustrates an example of a downlink (DL) / uplink (UL) sub-slot structure in a wireless communication system.

[0040] Figure 3 Is a diagram for explaining a physical channel used in a 3GPP system and a typical signal transmission method using the physical channel.

[0041] Figure 4a and 4b Illustrates a synchronization signal / physical broadcast channel (SS / PBCH) block for initial cell access in a 3GPP NR system.

[0042] Figure 5a and 5b Illustrates a process for transmitting control information and a control channel in a 3GPP NR system.

[0043] Figure 6 Illustrates a control resource set (CORESET) in which a physical uplink control channel (PUCCH) can be transmitted in a 3GPP NR system.

[0044] Figure 7The figure shows a method for configuring a PDCCH search space in a 3GPP NR system.

[0045] Figure 8 It is a conceptual diagram illustrating carrier aggregation.

[0046] Figure 9 It is a diagram for explaining signal carrier communication and multi-carrier communication.

[0047] Figure 10 It is a diagram showing an example where cross-carrier scheduling technology is applied.

[0048] Figure 11 It is a block diagram showing the configurations of a UE and a base station according to an embodiment of the present disclosure.

[0049] Figure 12 It is a diagram showing a process for generating a semi-static HARQ-ACK codebook according to an embodiment of the present invention.

[0050] Figure 13 It is a diagram illustrating a method for transmitting a PUCCH according to a PDSCH group indicator according to an embodiment of the present invention.

[0051] Figure 14 It is a diagram illustrating a situation where a conflict occurs when transmitting a PUCCH according to a PDSCH group indicator according to an embodiment of the present invention.

[0052] Figure 15 It is a diagram illustrating a method for transmitting a PUCCH when the unit of K1 is a half-slot according to an embodiment of the present invention.

[0053] Figure 16 It is a diagram illustrating a situation where a conflict occurs when transmitting a PUCCH when the unit of K1 is a half-slot according to an embodiment of the present invention.

[0054] Figure 17 It is a diagram illustrating a method for transmitting a PUCCH according to a HARQ-ACK multiplexing indicator according to an embodiment of the present invention.

[0055] Figure 18 It is a diagram illustrating a HARQ-ACK multiplexing method using a PRI when transmitting a PUCCH according to a HARQ-ACK multiplexing indicator according to an embodiment of the present invention.

[0056] Figure 19 It is a diagram illustrating a method for transmitting a PUCCH when there are no K1 and PRI fields according to an embodiment of the present invention.

[0057] Figure 20 It is a diagram showing the configuration of PDSCH candidates in a time slot.

[0058] Figure 21 It is a diagram illustrating the process of excluding overlapping PDSCH candidates according to an embodiment of the present invention.

[0059] Figure 22 It is a diagram illustrating the process of generating type 1 HARQ-ACK according to an embodiment of the present invention.

[0060] Figure 23 It is a diagram illustrating the process of generating type 1 HARQ-ACK according to an embodiment of the present invention.

[0061] Figure 24 It is a diagram showing a method of configuring PDSCH candidates and a DL association set (or PDSCH candidate set) when receiving PDSCH according to an embodiment of the present invention.

[0062] Figure 25 It is a diagram illustrating a method of reducing the HARQ-ACK size according to an embodiment of the present invention.

[0063] Figure 26 It is a diagram illustrating a method of reducing the HARQ-ACK size according to an embodiment of the present invention.

[0064] Figure 27 It is a diagram illustrating a method of reducing the HARQ-ACK size according to an embodiment of the present invention.

[0065] Figure 28 It is a diagram illustrating a method of reducing the HARQ-ACK size in the case of carrier aggregation according to an embodiment of the present invention.

[0066] Figure 29 It is a diagram illustrating a method of reducing the HARQ-ACK size in the case of carrier aggregation according to an embodiment of the present invention.

[0067] Figure 30 It is a diagram illustrating a method of reducing the HARQ-ACK size within one time slot according to an embodiment of the present invention.

[0068] Figure 31 It is a diagram illustrating a method of reducing the HARQ-ACK size within one time slot according to an embodiment of the present invention. Detailed implementation manners

[0069] The terms used in the specification are, to the extent possible in view of the functions in the present invention, adopted as the currently widely used general terms. However, these terms may be changed according to the intention, custom, and emergence of new technologies of those skilled in the art. Additionally, in specific cases, there are terms arbitrarily selected by the applicant, and in such cases, their meanings will be described in the corresponding description part of the present invention. Therefore, the intention is to disclose that the terms used in the specification should not be analyzed based only on the name of the term, but rather based on the substantial meaning of the term and the content throughout the specification.

[0070] Throughout the specification and the following claims, when an element is described as "connected" to another element, the element may be "directly connected" to the other element or "electrically connected" to the other element through a third element. Additionally, unless explicitly described to the contrary, the word "comprising" will be understood to imply the inclusion of the said elements, without implying the exclusion of any other elements. Furthermore, in some exemplary embodiments, limitations such as "greater than or equal to" or "less than or equal to" based on a specific threshold may be appropriately replaced with "greater than" or "less than", respectively.

[0071] The following technologies can be used in various wireless access systems: such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier - FDMA (SC - FDMA), etc. CDMA can be implemented by wireless technologies such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA can be implemented by wireless technologies such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). OFDMA can be implemented by wireless technologies such as IEEE 802.11 (Wi - Fi), IEEE 802.16 (WiMAX), IEEE 802 - 20, evolved UTRA (E - UTRA), etc. UTRA is part of the universal mobile telecommunications system (UMTS). The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of the evolved UMTS (E - UMTS) that uses evolved UMTS terrestrial radio access (E - UTRA), and LTE - Advanced (A) is an evolved version of 3GPP LTE. 3GPP New Radio (NR) is a system designed separately from LTE / LTE - A and is a system for supporting enhanced mobile broadband (eMBB), ultra - reliable low - latency communication (URLLC), and massive machine - type communication (mMTC) services as requirements of IMT - 2020. For the sake of clear description, 3GPP NR is mainly described, but the technical idea of the present invention is not limited thereto.

[0072] Unless otherwise specified herein, a base station may include a next-generation node B (gNB) defined in 3GPP NR. In addition, unless otherwise specified, a terminal may include a user equipment (UE). Hereinafter, for the sake of understanding the description, each content is described separately by way of examples, but each example may be used in combination. In this specification, the configuration of the UE may be indicated by the configuration of the base station. More specifically, the base station may configure the value of a parameter used in the operation of the UE or the radio communication system by transmitting a channel or a signal to the UE.

[0073] Figure 1 An example of a radio frame structure used in a radio communication system is illustrated.

[0074] Reference Figure 1 , a radio frame (or radio frame) used in the 3GPP NR system may have a length of 10 ms (Δf max N f / 100)*T c ). In addition, the radio frame includes 10 subframes (SFs) of equal size. Here, Δf max = 480*10 3 Hz, N f = 4096, T c = 1 / (Δf ref *N f,ref ), Δf ref = 15*10 3 Hz, and N f,ref = 2048. Numbers from 0 to 9 may be assigned to the 10 subframes within one radio frame, respectively. The length of each subframe is 1 ms and may include one or more time slots according to the subcarrier spacing. More specifically, in the 3GPP NR system, the subcarrier spacing that can be used is 15*2 μ kHz, and μ can have values of μ = 0, 1, 2, 3, 4 as subcarrier spacing configurations. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz can be used for the subcarrier spacing. One subframe with a length of 1 ms may include 2 μ time slots. In this case, the length of each time slot is 2 -μ ms. Numbers from 0 to 2 μ - 1 may be assigned to the 2 μ time slots within one subframe, respectively. In addition, numbers from 0 to 10*2 μ - 1 may be assigned to the time slots within one radio frame, respectively. Time resources may be distinguished by at least one of a radio frame number (also referred to as a radio frame index), a subframe number (also referred to as a subframe index), and a time slot number (or time slot index).

[0075] Figure 2 An example of a downlink (DL) / uplink (UL) time slot structure in a wireless communication system is illustrated. In particular, Figure 2 The structure of the resource grid of the 3GPP NR system is shown.

[0076] There is one resource grid per antenna port. Refer to Figure 2 , a time slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. One OFDM symbol also refers to a symbol interval. Unless otherwise specified, the OFDM symbol can be abbreviated as a symbol for simplicity. One RB includes 12 consecutive subcarriers in the frequency domain. Refer to Figure 2 , the signal transmitted from each time slot can be represented by a resource grid including N size,μ grid,x *N RB sc subcarriers and N slot symb OFDM symbols. Here, when the signal is a DL signal, x = DL, and when the signal is a UL signal, x = UL. N size,μ grid,x represents the number of resource blocks (RBs) according to the subcarrier spacing component μ (x is DL or UL), and N slot symb represents the number of OFDM symbols in a time slot. N RB sc is the number of subcarriers that make up one RB and N RB sc = 12. The OFDM symbol can be referred to as a cyclic prefix OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol according to the multiple access scheme.

[0077] The number of OFDM symbols included in a time slot can vary according to the length of the cyclic prefix (CP). For example, in the case of a normal CP, a time slot includes 14 OFDM symbols, but in the case of an extended CP, a time slot can include 12 OFDM symbols. In a specific embodiment, the extended CP can only be used at a 60 kHz subcarrier spacing. In Figure 2 , for the convenience of description, as an example, a time slot is configured with 14 OFDM symbols, but the embodiments of the present disclosure can be applied to time slots with different numbers of OFDM symbols in a similar manner. Refer to Figure 2 , each OFDM symbol includes N size,μ grid,x *N RB scSub - carriers. The types of sub - carriers can be divided into data sub - carriers for data transmission, reference signal sub - carriers for the transmission of reference signals, and guard bands. The carrier frequency is also referred to as the center frequency (fc).

[0078] An RB can be defined by N RB sc (e.g., 12) consecutive sub - carriers in the frequency domain. For reference, a resource configured with one OFDM symbol and one sub - carrier can be called a resource element (RE) or a tone. Thus, an RB can be configured with N slot symb *N RB sc resource elements. Each resource element in the resource grid can be uniquely defined by a pair of indices (k, l) in a time slot. k can be the index assigned from 0 to N size,μ grid,x *N RB sc – 1, and l can be the index assigned from 0 to N slot symb – 1.

[0079] For the UE to receive signals from the base station or send signals to the base station, the time / frequency of the UE can be synchronized with the time / frequency of the base station. This is because when the base station and the UE are synchronized, the UE can determine the time and frequency parameters necessary to demodulate the DL signal and transmit the UL signal at the correct time.

[0080] Each symbol of a radio frame used in time - division duplex (TDD) or unpaired spectrum can be configured with at least one of DL symbols, UL symbols, and flexible symbols. A radio frame used as a DL carrier in frequency - division duplex (FDD) or paired spectrum can be configured with DL symbols or flexible symbols, while a radio frame used as a UL carrier can be configured with UL symbols or flexible symbols. In DL symbols, DL transmission is possible, but UL transmission is not. In UL symbols, UL transmission is possible, but DL transmission is not. A flexible symbol can be determined to be used as DL or UL according to the signal.

[0081] Information about the type of each symbol, i.e., information indicating any one of a DL symbol, a UL symbol, and a flexible symbol, may be configured with a cell-specific or common Radio Resource Control (RRC) signal. Additionally, information about the type of each symbol may be additionally configured with a UE-specific or dedicated RRC signal. The base station notifies, by using the cell-specific RRC signal, i) the period of the cell-specific slot configuration, ii) the number of slots having only DL symbols from the beginning of the period of the cell-specific slot configuration, iii) the number of DL symbols starting from the first symbol of the slot immediately following the slot having only DL symbols, iv) the number of slots having only UL symbols from the end of the period of the cell-specific slot configuration, and v) the number of UL symbols starting from the last symbol of the slot immediately preceding the slot having only UL symbols. Here, a symbol not configured with any one of the UL symbol and the DL symbol is a flexible symbol.

[0082] When the information about the symbol type is configured with a UE-specific RRC signal, the base station may signal whether the flexible symbol is a DL symbol or a UL symbol with the cell-specific RRC signal. In this case, the UE-specific RRC signal cannot change a DL symbol or a UL symbol configured with the cell-specific RRC signal into another symbol type. The UE-specific RRC signal may signal the number of DL symbols among the N slot symb symbols of the corresponding slot of each slot and the number of UL symbols among the N slot symb symbols of the corresponding slot. In this case, the DL symbols of the slot may be continuously configured from the first symbol to the i-th symbol of the slot. Additionally, the UL symbols of the slot may be continuously configured from the j-th symbol to the last symbol of the slot (where i < j). In a slot, a symbol not configured with any one of the UL symbol and the DL symbol is a flexible symbol.

[0083] The symbol type configured with the above RRC signal may be referred to as a semi-static DL / UL configuration. In the semi-static DL / UL configuration previously configured with the RRC signal, the flexible symbol may be indicated as a DL symbol, a UL symbol, or a flexible symbol by dynamic slot format information (SFI) transmitted on a Physical DL Control Channel (PDCCH). In this case, a DL symbol or a UL symbol configured with the RRC signal does not change to another symbol type. Table 1 illustrates the dynamic SFI that the base station may indicate to the UE.

[0084] [Table 1]

[0085]

[0086] In Table 1, D represents a DL symbol, U represents a UL symbol, and X represents a flexible symbol. As shown in Table 1, up to two DL / UL switches are allowed in one time slot.

[0087] Figure 3 is a diagram for explaining physical channels used in a 3GPP system (e.g., NR) and a typical signal transmission method using the physical channels.

[0088] If the power of the UE is turned on or the UE camps on a new cell, the UE performs initial cell search (S101). Specifically, the UE can synchronize with the BS during the initial cell search. To this end, the UE can receive the primary synchronization signal (PSS) and the secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as the cell ID. Thereafter, the UE is able to receive the physical broadcast channel from the base station and obtain the broadcast information in the cell.

[0089] When the initial cell search is completed, the UE receives the physical downlink shared channel (PDSCH) according to the physical downlink control channel (PDCCH) and the information in the PDCCH, so that the UE can obtain more specific system information than the system information obtained through the initial cell search (S102). In this document, the system information received by the UE is the cell common system information for the normal operation of the UE in the physical layer in radio resource control (RRC) and is referred to as the remaining system information, or system information block (SIB) 1.

[0090] When the UE initially accesses the base station or does not have radio resources for signal transmission (i.e., the UE is in the RRC_IDLE mode), the UE can perform a random access procedure (Operations S103 to S106) on the base station. First, the UE can send a preamble through the physical random access channel (PRACH) (S103) and receive a response message for the preamble from the base station through the PDCCH and the corresponding PDSCH (S104). When the UE receives a valid random access response message, the UE sends data including the identifier of the UE, etc. to the base station through the physical uplink shared channel (PUSCH) indicated by the UL grant sent by the base station through the PDCCH (S105). Next, the UE waits for the reception of the PDCCH as an indication from the base station for conflict resolution. If the UE successfully receives the PDCCH (S106) through the identifier of the UE, the random access procedure is terminated. The UE can obtain UE-specific system information for the normal operation of the UE in the physical layer in the RRC layer during the random access procedure. When the UE obtains the UE-specific system information, the UE enters the RRC connected mode (RRC_CONNECTED mode).

[0091] The RRC layer is used to generate or manage messages for controlling the connection between a UE and a radio access network (RAN). More specifically, in the RRC layer, a base station and a UE can perform functions such as broadcasting cell system information required for each UE in a cell, managing the delivery of paging messages, managing mobility and handover, controlling the measurement reports of the UE and its control, UE capability management, and storage management. Generally, since the update period of the signals delivered in the RRC layer is longer than the transmission time interval (TTI) in the physical layer, the RRC signals do not change and are maintained for a relatively long period.

[0092] After the above process, the UE receives PDCCH / PDSCH (S107) and transmits a physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) (S108) as a general UL / DL signal transmission process. In particular, the UE can receive downlink control information (DCI) through the PDCCH. The DCI can include control information such as resource allocation information for the UE. Additionally, the format of the DCI can vary according to a predetermined use. The uplink control information (UCI) sent by the UE to the base station via the UL includes DL / UL ACK / NACK signals, a channel quality indicator (CQI), a precoding matrix index (PMI), a rank indicator (RI), etc. Here, the CQI, PMI, and RI can be included in the channel state information (CSI). In the 3GPP NR system, the UE can send control information such as the above-mentioned HARQ-ACK and CSI through the PUSCH and / or PUCCH.

[0093] Figure 4a and 4b illustrates an SS / PBCH block for initial cell access in the 3GPP NR system. When the power is turned on or when the UE wants to access a new cell, the UE can obtain time and frequency synchronization with the cell and perform an initial cell search process. The UE can detect the physical cell identity N of the cell during the cell search process. cell ID For this purpose, the UE can receive synchronization signals, such as a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), from the base station and synchronize with the base station. In this case, the UE can obtain information such as the cell identity (ID).

[0094] Reference Figure 4a , the synchronization signal (SS) will be described in more detail. The synchronization signal can be classified into a PSS and an SSS. The PSS can be used to obtain time-domain synchronization and / or frequency-domain synchronization, such as OFDM symbol synchronization and slot synchronization. The SSS can be used to obtain frame synchronization and the cell group ID. Reference Figure 4aAs shown in Table 1, the SS / PBCH block can be configured with 20 consecutive RBs (= 240 subcarriers) on the frequency axis and can be configured with 4 consecutive OFDM symbols on the time axis. In this case, in the SS / PBCH block, the PSS is transmitted in the first OFDM symbol and the SSS is transmitted in the third OFDM symbol through subcarriers No. 56 to No. 182. Here, the lowest subcarrier index of the SS / PBCH block is numbered from 0. In the first OFDM symbol where the PSS is transmitted, the base station does not transmit signals through the remaining subcarriers, i.e., subcarriers No. 0 to No. 55 and subcarriers No. 183 to No. 239. In addition, in the third OFDM symbol where the SSS is transmitted, the base station does not transmit signals through subcarriers No. 48 to No. 55 and subcarriers No. 183 to No. 191. The base station transmits the physical broadcast channel (PBCH) through the remaining REs in the SS / PBCH block other than the above signals.

[0095] [Table 2]

[0096]

[0097] The SS allows a total of 1008 unique physical layer cell IDs to be grouped into 336 physical layer cell identifier groups through the combination of three PSSs and SSSs, with each group including three unique identifiers. Specifically, such that each physical layer cell ID will be only part of one physical layer cell identifier group. Thus, the physical layer cell ID N cell ID = 3N (1) ID + N (2) ID can be uniquely defined by an index N indicating the range of the physical layer cell identifier group from 0 to 335 (1) ID and an index N indicating the range of the physical layer identifier in the physical layer cell identifier group from 0 to 2 (2) ID The UE can detect the PSS and identify one of the three unique physical layer identifiers. In addition, the UE can detect the SSS and identify one of the 336 physical layer cell IDs associated with the physical layer identifier. In this case, the sequence d PSS (n) is as follows.

[0098] d PSS (n) = 1 - 2x(m)

[0099] m = (n + 43N (2) ID ) mod 127

[0100] 0 ≤ n < 127

[0101] Here, x(i + 7) = (x(i + 4) + x(i)) mod 2 and is given as

[0102] [x(6) x(5) x(4) x(3) x(2) x(1) x(0)] = [1 1 1 0 1 1 0]

[0103] In addition, the sequence d of the SSS SSS (n) is as follows.

[0104] d SSS (n) = [1 - 2x0((n + m0) mod 127][1 - 2x i ((n + m1) mod 127]

[0105] m0 = 15 floor(N (1) ID / 112) + 5N (2) ID

[0106] m1 = N (1) ID mod 112

[0107] 0 ≤ n < 127

[0108] Here, x0(i + 7) = (x0(i + 4) + x0(i)) mod 2

[0109] x1(i + 7) = (x1(i + 1) + x1(i)) mod 2 and is given as

[0110] [x0(6) x0(5) x0(4) x0(3) x0(2) x0(1) x0(0)] = [0 0 0 0 0 0 1]

[0111] [x1(6) x1(5) x1(4) x1(3) x1(2) x1(1) x1(0)] = [0 0 0 0 0 0 1]

[0112] A radio frame with a length of 10 ms can be divided into two half - frames with a length of 5 ms. Refer to Figure 4b, the time slots for transmitting SS / PBCH blocks in each half-frame will be described. The time slots for transmitting SS / PBCH blocks can be any one of cases A, B, C, D, and E. In case A, the subcarrier spacing is 15 kHz and the starting time point of the SS / PBCH block is the ({2,8}+14*n)-th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0 or 1. Additionally, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n can be 0, 1, 2, 3. In case B, the subcarrier spacing is 30 kHz and the starting time point of the SS / PBCH block is {4,8,16,20}+28*n. In this case, at a carrier frequency of 3 GHz or lower, n = 0. Additionally, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n can be 0, 1. In case C, the subcarrier spacing is 30 kHz and the starting time point of the SS / PBCH block is the ({2,8}+14*n)-th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0 or 1. Additionally, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n can be 0, 1, 2, 3. In case D, the subcarrier spacing is 120 kHz and the starting time point of the SS / PBCH block is the ({4,8,16,20}+28*n)-th symbol. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In case E, the subcarrier spacing is 240 kHz and the starting time point of the SS / PBCH block is the ({8,12,16,20,32,36,40,44}+56*n)-th symbol. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0113] Figure 5a and 5b illustrates the process for transmitting control information and control channels in a 3GPP NR system. Refer to Figure 5a, the base station may add a cyclic redundancy check (CRC) masked (e.g., by exclusive OR operation) with a radio network temporary identifier (RNTI) to the control information (e.g., downlink control information (DCI)) (S202). The base station may scramble the CRC with an RNTI value determined according to the purpose / target of each control information. The common RNTIs used by one or more UEs may include at least one of a system information RNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI), and a transmit power control RNTI (TPC-RNTI). In addition, the UE-specific RNTIs may include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, the base station may perform rate matching (S206) according to the amount of resources used for PDCCH transmission after performing channel coding (e.g., polar coding) (S204). Thereafter, the base station may multiplex the DCI based on a PDCCH structure based on control channel elements (CCEs) (S208). In addition, the base station may apply additional processes such as scrambling, modulation (e.g., QPSK), interleaving, etc. to the multiplexed DCI (S210), and then map the DCI to the resources to be transmitted. A CCE is the basic resource unit for the PDCCH, and one CCE may include multiple (e.g., six) resource element groups (REGs). One REG may be configured with multiple (e.g., 12) resource elements (REs). The number of CCEs used for one PDCCH may be defined as the aggregation level. In the 3GPP NR system, aggregation levels of 1, 2, 4, 8, or 16 may be used. Figure 5b is a diagram related to the CCE aggregation level and the multiplexing of the PDCCH, and illustrates the type of CCE aggregation level for one PDCCH and the CCEs transmitted in the control region accordingly.

[0114] Figure 6 Illustrates a control resource set (CORESET) in the 3GPP NR system in which a physical downlink control channel (PUCCH) can be transmitted.

[0115] A CORESET is time-frequency resources in which PDCCH (i.e., control signals for UEs) is transmitted. Additionally, a search space to be described later can be mapped to a CORESET. Thus, a UE can monitor the time-frequency domain designated as a CORESET instead of monitoring all frequency bands for PDCCH reception, and decode the PDCCH mapped to the CORESET. A base station can configure one or more CORESETs for a UE for each cell. A CORESET can be configured with up to three consecutive symbols on the time axis. Additionally, a CORESET can be configured in units of six consecutive PRBs on the frequency axis. In the embodiment of FIG. 5, CORESET #1 is configured with consecutive PRBs, while CORESET #2 and CORESET #3 are configured with non-consecutive PRBs. A CORESET can be located in any symbol in a time slot. For example, in the embodiment of FIG. 5, CORESET #1 starts from the first symbol of the time slot, CORESET #2 starts from the fifth symbol of the time slot, and CORESET #9 starts from the ninth symbol of the time slot.

[0116] Figure 7 FIG. illustrates a method for setting a PUCCH search space in a 3GPP NR system.

[0117] To transmit PDCCH to a UE, each CORESET can have at least one search space. In an embodiment of the present disclosure, a search space is a set of all time-frequency resources (hereinafter, PDCCH candidates) that can be used to transmit PDCCH for a UE. A search space can include a common search space that requires UEs of 3GPP NR to search jointly and a UE-specific search space or UE-specific search space that requires a specific UE to search. In the common search space, a UE can monitor PDCCH that is set such that all UEs in cells belonging to the same base station search jointly. Additionally, a UE-specific search space can be set for each UE such that the UE monitors the PDCCH assigned to each UE at search space positions that differ according to the UE. In the case of a UE-specific search space, since a limited control region where PDCCH can be allocated, the search spaces between UEs can partially overlap and be allocated. Monitoring PDCCH includes blindly decoding PDCCH candidates in a search space. When the blind decoding is successful, it can be expressed as (successfully) detecting / receiving PDCCH, while when the blind decoding fails, it can be expressed as not detected / not received or not successfully detected / not received PDCCH.

[0118] For the sake of convenience of explanation, a Physical Downlink Control Channel (PDCCH) that is scrambled with a group common (GC) RNTI known to one or more UEs in advance to send downlink control information to one or more UEs is referred to as a group common (GC) PDCCH or a common PDCCH. In addition, a PDCCH that is scrambled with an RNTI of a specific terminal known to a specific UE to send uplink scheduling information or downlink scheduling information to the specific UE is referred to as a UE-specific PDCCH. The common PDCCH can be included in a common search space, and the UE-specific PDCCH can be included in the common search space or the UE-specific search space.

[0119] The base station can signal to each UE or UE group via the PDCCH information regarding resource allocation related to the paging channel (PCH) and the downlink shared channel (DL-SCH) as transmission channels (i.e., DL grant) or information regarding resource allocation related to the uplink shared channel (UL-SCH) and hybrid automatic repeat request (HARQ) (i.e., UL grant). The base station can send a PCH transport block and a DL-SCH transport block via the PDSCH. The base station can send data excluding specific control information or specific service data via the PDSCH. In addition, the UE can receive data excluding specific control information or specific service data via the PDSCH.

[0120] The base station can include in the PDCCH information on which UE(s) the PDSCH data is to be sent to and how the PDSCH data will be received and decoded by the corresponding UE, and send the PDCCH. For example, assume that the DCI transmitted on a specific PDCCH is CRC masked with an RNTI "A", and the DCI indicates that the PDSCH is allocated to radio resources "B" (e.g., frequency position) and indicates transmission format information "C" (e.g., transport block size, modulation scheme, coding information, etc.). The UE uses the RNTI information the UE has to monitor the PDCCH. In this case, if there is a UE that performs blind decoding of the PDCCH using the "A" RNTI, the UE receives the PDCCH and receives the PDSCH indicated by "B" and "C" based on the information of the received PDCCH.

[0121] Table 3 shows an embodiment of the Physical Uplink Control Channel (PUCCH) used in a wireless communication system.

[0122] [Table 3]

[0123] PUCCH format Length of OFDM symbol Number of bits 0 1-2 ≤2 1 4-14 ≤2 2 1-2 ＞2 3 4-14 ＞2 4 4-14 ＞2

[0124] The PUCCH can be used to send the following uplink control information (UCI).

[0125] - Scheduling Request (SR): Information used to request UL UL-SCH resources.

[0126] - HARQ-ACK: Response to PDCCH (indicating DL SPS release) and / or response to DL transport block (TB) on PDSCH. HARQ-ACK indicates whether the information sent on PDCCH or PDSCH is received. The HARQ-ACK response includes positive ACK (simply referred to as ACK), negative ACK (NACK hereinafter), discontinuous transmission (DTX), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK / NACK and ACK / NACK. Generally, ACK can be represented by bit value 1, while NACK can be represented by bit value 0.

[0127] - Channel State Information (CSI): Feedback information about DL channels. The UE generates it based on the CSI-reference signal (RS) sent by the base station. The feedback information related to multiple-input multiple-output (MIMO) includes rank indicator (RI) and precoding matrix indicator (PMI). The CSI can be divided into CSI part 1 and CSI part 2 according to the information indicated by CSI.

[0128] In the 3GPP NR system, five PUCCH formats can be used to support various service scenarios, various channel environments, and frame structures.

[0129] PUCCH format 0 is a format capable of delivering 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 can be sent through one or two OFDM symbols on the time axis and one PRB on the frequency axis. When PUCCH format 0 is sent in two OFDM symbols, the same sequence on the two symbols can be sent through different RBs. In this case, the sequence can be a sequence obtained by cyclic shift (CS) from the basic sequence used in PUCCH format 0. Through this, the UE can obtain frequency diversity gain. More specifically, the UE can determine the cyclic shift (CS) value m bit according to the M bit -bit UCI (M cs = 1 or 2). Additionally, the basic sequence of length 12 can be sent by mapping the cyclic shift sequence based on the pre-determined CS value m cs to 12 REs of 1 OFDM symbol and 1 RB. When the number of available cyclic shifts for the UE is 12 and M bit = 1, 1-bit UCI 0 and 1 can be mapped to two cyclic shift sequences with a cyclic shift difference of 6 respectively. Additionally, when M bitWhen M = 2, 2-bit UCI 00, 01, 11, and 10 can be mapped to four cyclic shift sequences with a cyclic shift value difference of 3 respectively.

[0130] PUCCH format 1 can carry 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 can be transmitted through consecutive OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 can be one of 4 to 14. More specifically, for M bit = 1 UCI, BPSK modulation can be performed. The UE can use Quadrature Phase Shift Keying (QPSK) to modulate the UCI with M bit = 2. The signal is obtained by multiplying the modulated complex-valued symbol d(0) by a sequence of length 12. In this case, the sequence can be the basic sequence for PUCCH format 0. The UE extends the even-numbered OFDM symbols assigned to PUCCH format 1 through a time-axis Orthogonal Cover Code (OCC) to transmit the obtained signal. PUCCH format 1 determines the maximum number of different UEs multiplexed in one RB according to the length of the OCC to be used. The Demodulation Reference Signal (DMRS) can be extended with the OCC and mapped to the odd-numbered OFDM symbols of PUCCH format 1.

[0131] PUCCH format 2 can carry UCI of more than 2 bits. PUCCH format 2 can be transmitted through one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. When PUCCH format 2 is transmitted in two OFDM symbols, the sequences transmitted in different RBs through the two OFDM symbols can be the same. Here, the sequence can be multiple modulated complex-valued symbols d(0),..., d(M symbol - 1). Here, M symbol can be M bit / 2. Through this, the UE can obtain a frequency diversity gain. More specifically, for M bit bits of UCI (M bit > 2), bit-level scrambling, QPSK modulation are performed, and it is mapped to the RBs of one or two OFDM symbols. Here, the number of RBs can be one of 1 to 16.

[0132] PUCCH format 3 or PUCCH format 4 can carry UCI of more than 2 bits. PUCCH format 3 or PUCCH format 4 can be transmitted through consecutive OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 can be one of 4 to 14. Specifically, the UE utilizes Binary Phase Shift Keying (BPSK) or QPSK modulates M bit bits of UCI (M bit >2) to generate complex-valued symbols d(0) to d(M symb -1). Here, when using π / 2-BPSK, M symb = M bit , and when using QPSK, M symb = M bit / 2. The UE may not apply block unit extension to PUCCH format 3. However, the UE may use a PreDFT-OCC of length 12 to apply block unit extension to one RB (i.e., 12 subcarriers) so that PUCCH format 4 may have two or four multiplexing capabilities. The UE performs transmit precoding (or DFT precoding) on the extended signal and maps it to each RE to transmit the extended signal.

[0133] In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 can be determined according to the length and maximum coding rate of the UCI transmitted by the UE. When the UE uses PUCCH format 2, the UE may transmit HARQ-ACK information and CSI information together through the PUCCH. When the number of RBs that the UE can transmit is greater than the maximum number of RBs that PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the UE may only transmit the remaining UCI information without transmitting some UCI information according to the priority of the UCI information.

[0134] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured by an RRC signal to indicate frequency hopping in a time slot. When frequency hopping is configured, the index of the RB to be frequency-hopped can be configured by an RRC signal. When transmitting PUCCH format 1, PUCCH format 3, or PUCCH format 4 over N OFDM symbols on the time axis, the first hop may have floor(N / 2) OFDM symbols and the second hop may have ceiling(N / 2) OFDM symbols.

[0135] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured to be repeatedly transmitted in multiple time slots. In this case, the number K of time slots for repeatedly transmitting the PUCCH can be configured by an RRC signal. The repeatedly transmitted PUCCH must start from an OFDM symbol at a constant position in each time slot and have a constant length. When one OFDM symbol among the OFDM symbols of the time slot in which the UE is supposed to transmit the PUCCH is indicated as a DL symbol by an RRC signal, the UE may not transmit the PUCCH in the corresponding time slot and delay the transmission of the PUCCH to the next time slot to transmit the PUCCH.

[0136] Meanwhile, in the 3GPP NR system, the UE can perform transmission / reception using a bandwidth equal to or less than the bandwidth of a carrier (or cell). To this end, the UE can receive a bandwidth part (BWP) configured with a continuous bandwidth of some of the carrier bandwidth. A UE operating according to TDD operation or in an unpaired spectrum can receive up to four DL / UL BWP pairs in one carrier (or cell). In addition, the UE can activate one DL / UL BWP pair. A UE operating according to FDD operation or in a paired spectrum can receive up to four DL BWPs on a DL carrier (or cell) and receive up to four UL BWPs on a UL carrier (or cell). For each carrier (or cell), the UE can activate one DL BWP and one UL BWP. The UE may not perform reception or transmission in time-frequency resources other than the activated BWP. The activated BWP can be referred to as an active BWP.

[0137] The base station can indicate the activated BWP among the BWPs configured by the UE through downlink control information (DCI). The BWP indicated by the DCI is activated, while other configured BWPs are deactivated. In a carrier (or cell) operating according to TDD operation, the base station can include a bandwidth part indicator (BPI) indicating the BWP to be activated to change the DL / UL BWP pair of the UE in the DCI for scheduling the PDSCH or PUSCH. The UE can receive the DCI for scheduling the PDSCH or PUSCH and can identify the DL / UL BWP pair activated based on the BPI. For a DL carrier (or cell) operating in FDD, the base station can include the BPI indicating the BWP to be activated in the DCI for scheduling the PDSCH to change the DL BWP of the UE. For a UL carrier (or cell) operating in FDD, the base station can include the BPI indicating the BWP to be activated in the DCI for scheduling the PUSCH to change the UL BWP of the UE.

[0138] Figure 8 is a conceptual diagram illustrating carrier aggregation.

[0139] Carrier aggregation is a method in which a UE uses multiple frequency blocks or (in a logical sense) cells configured with UL resources (or component carriers) and / or DL resources (or component carriers) as a large logical frequency band so that a wireless communication system can use a wider frequency band. A component carrier can also be referred to by terms such as primary cell (PCell) or secondary cell (SCell) or primary SCell (PScell). However, hereinafter, for the sake of convenience in description, the term "component carrier" is used.

[0140] Reference Figure 8 , as an example of a 3GPP NR system, the entire system bandwidth can include up to 16 component carriers, and each component carrier can have a bandwidth of up to 400 MHz. A component carrier can include one or more physically contiguous subcarriers. Although each component carrier is shown in Figure 8 as having the same bandwidth, this is merely an example, and each component carrier can have a different bandwidth. Additionally, although each component carrier is shown as being adjacent to each other on the frequency axis, the figures are shown in a logical concept, and each component carrier can be physically adjacent to each other or can be spaced apart.

[0141] Different center frequencies can be used for each component carrier. Additionally, a common center frequency can be used in physically adjacent component carriers. Assuming that in the Figure 8 embodiment all component carriers are physically adjacent, the center frequency A can be used in all component carriers. Additionally, assuming that the respective component carriers are not physically adjacent to each other, the center frequency A and the center frequency B can be used in each component carrier.

[0142] When expanding the total system bandwidth through carrier aggregation, the frequency band used for communicating with each UE can be defined in units of component carriers. UE A can use 100 MHz as the total system bandwidth and use all five component carriers to perform communication. UE B1 - B5 can each use only 20 MHz of bandwidth and use one component carrier to perform communication. UE C1 and C2 can each use 40 MHz of bandwidth and use two component carriers to perform communication. These two component carriers can be logically / physically adjacent or not adjacent. UE C1 represents the case of using two non - adjacent component carriers, while UE C2 represents the case of using two adjacent component carriers.

[0143] Figure 9 are diagrams for illustrating signal carrier communication and multi - carrier communication. In particular, Figure 9 (a) shows a single - carrier sub - frame structure and Figure 9 (b) shows a multi - carrier sub - frame structure.

[0144] Reference Figure 9(a), In the FDD mode, a general wireless communication system can perform data transmission or reception through a DL frequency band and a corresponding UL frequency band. In another specific embodiment, in the TDD mode, the wireless communication system can divide a radio frame into UL time units and DL time units in the time domain, and perform data transmission or reception through the UL / DL time units. Refer to Figure 9 (b), It is possible to aggregate three 20 MHz component carriers (CCs) into each of the UL and DL, enabling support for a 60 MHz bandwidth. Each CC can be adjacent or non - adjacent to each other in the frequency domain. Figure 9 (b) shows a case where the bandwidths of the UL CC and the DL CC are the same and symmetric, but the bandwidth of each CC can be determined independently. In addition, asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is possible. The DL / UL CCs allocated / configured to a specific UE through RRC can be referred to as the serving DL / UL CCs of the specific UE.

[0145] The base station can communicate with the UE by activating some or all of the serving CCs of the UE or deactivating some CCs. The base station can change the CCs to be activated / deactivated and the number of CCs to be activated / deactivated. If the base station allocates the CCs available to the UE as cell - specific or UE - specific, at least one of the allocated CCs will not be deactivated unless the CC allocation for the UE is completely re - configured or the UE is handed over. A CC not deactivated by the UE is called the primary CC (PCC) or primary cell (PCell), while the CCs that the base station can freely activate / deactivate are called secondary CCs (SCCs) or secondary cells (SCells).

[0146] Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of DL resources and UL resources, i.e., a combination of a DL CC and a UL CC. A cell can be configured separately with DL resources, or can be configured with a combination of DL resources and UL resources. When carrier aggregation is supported, the link between the carrier frequency of the DL resource (or DL CC) and the carrier frequency of the UL resource (or UL CC) can be indicated by system information. The carrier frequency refers to the center frequency of each cell or CC. The cell corresponding to the PCC is called the PCell, and the cell corresponding to the SCC is called the SCell. The carrier corresponding to the PCell in the DL is the DL PCC, and the carrier corresponding to the PCell in the UL is the UL PCC. Similarly, the carrier corresponding to the SCell in the DL is the DL SCC, and the carrier corresponding to the SCell in the UL is the UL SCC. Depending on the UE capabilities, a serving cell can be configured with one PCell and zero or more SCells. In the case of a UE in the RRC_CONNECTED state but not configured for carrier aggregation or not supporting carrier aggregation, there is only one serving cell configured only with a PCell.

[0147] As described above, the term "cell" used in carrier aggregation is distinguished from the term "cell" referring to a certain geographical area that provides communication services through a base station or a set of antennas. That is, a component carrier can also be called a scheduling cell, a scheduled cell, a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, to distinguish between the cell representing a certain geographical area and the cell in carrier aggregation, in the present disclosure, the cell in carrier aggregation is called a CC, and the cell of the geographical area is called a cell.

[0148] Figure 10 FIG. is a diagram showing an example where a cross-carrier scheduling technique is applied. When cross-carrier scheduling is set, the control channel transmitted through the first CC can use the Carrier Indicator Field (CIF) to schedule the data channel transmitted through the first CC or the second CC. The CIF is included in the DCI. In other words, a scheduling cell is set, and the DL grant / UL grant transmitted in the PDCCH area of the scheduling cell schedules the PDSCH / PUSCH of the scheduled cell. That is, there is a search area for multiple component carriers in the PDCCH area of the scheduling cell. The PCell can basically be the scheduling cell, and a specific SCell can be designated as the scheduling cell by the upper layer.

[0149] In Figure 10In an embodiment, it is assumed that three DL CCs are combined. Here, it is assumed that DL component carrier #0 is the DLPCC (or PCell), and DL component carriers #1 and #2 are DL SCCs (or SCell). In addition, it is assumed that the DLPCC is set as the PDCCH monitoring CC. When cross-carrier scheduling is not configured by UE-specific (or UE group-specific or cell-specific) higher layer signaling, the CIF is disabled, and each DL CC can send only the PDCCH for scheduling its PDSCH without the CIF according to the NR PDCCH rules (non-cross-carrier scheduling, self-carrier scheduling). At the same time, if cross-carrier scheduling is configured by UE-specific (or UE group-specific or cell-specific) higher layer signaling, the CIF is enabled, and a specific CC (e.g., the DL PCC) can use the CIF to send not only the PDCCH for scheduling the PDSCH of DL CC A but also the PDCCH for scheduling the PDSCH of another CC (cross-carrier scheduling). On the other hand, no PDCCH is sent in another DL CC. Therefore, the UE monitors the PDCCH without the CIF to receive the self-carrier scheduled PDSCH according to whether cross-carrier scheduling is configured for the UE, or monitors the PDCCH including the CIF to receive the cross-carrier scheduled PDSCH.

[0150] On the other hand, Figure 9 and Figure 10 FIG. illustrates the subframe structure of the 3GPP LTE-A system, and the same or similar configurations can be applied to the 3GPP NR system. However, in the 3GPP NR system, Figure 9 and Figure 10 the subframe can be replaced by a time slot.

[0151] Figure 11 is a block diagram showing the configurations of a UE and a base station according to an embodiment of the present disclosure. In an embodiment of the present disclosure, the UE can be implemented using various types of wireless communication devices or computing devices that are guaranteed to be portable and mobile. The UE can be referred to as a user equipment (UE), a station (STA), a mobile subscriber (MS), etc. In addition, in an embodiment of the present disclosure, the base station controls and manages a cell corresponding to a service area (e.g., a macro cell, a femto cell, a pico cell, etc.), and performs functions such as signal transmission, channel assignment, channel monitoring, self-diagnosis, relaying, etc. The base station can be referred to as a next-generation node B (gNB) or an access point (AP).

[0152] As shown in the drawings, a UE 100 according to an embodiment of the present disclosure may include a processor 110, a communication module 120, a memory 130, a user interface 140, and a display unit 150.

[0153] First, the processor 110 may execute various instructions or processes and process data within the UE 100. In addition, the processor 110 may control the overall operation of each unit including the UE 100 and may control the transmission / reception of data between the units. Here, the processor 110 may be configured to perform operations according to the embodiments described in the present disclosure. For example, the processor 110 may receive slot configuration information, determine a slot configuration based on the slot configuration information, and perform communication according to the determined slot configuration.

[0154] Next, the communication module 120 may be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 120 may include multiple network interface cards (NICs) in an internal or external form, such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123. In the drawings, the communication module 120 is shown as an overall integrated module, but different from the drawings, each network interface card can be independently arranged according to the circuit configuration or usage.

[0155] The cellular communication interface card 121 may transmit or receive radio signals to / from at least one of the base station 200, an external device, and a server using a mobile communication network and provide cellular communication services in a first frequency band based on instructions from the processor 110. According to an embodiment, the cellular communication interface card 121 may include at least one NIC module using a frequency band less than 6 GHz. At least one NIC module of the cellular communication interface card 121 may independently perform cellular communication with at least one of the base station 200, an external device, and a server in a frequency band below 6 GHz supported by the corresponding NIC module according to cellular communication standards or protocols.

[0156] The cellular communication interface card 122 may transmit or receive radio signals to / from at least one of the base station 200, an external device, and a server using a mobile communication network and provide cellular communication services in a second frequency band based on instructions from the processor 110. According to an embodiment, the cellular communication interface card 122 may include at least one NIC module using a frequency band greater than 6 GHz. At least one NIC module of the cellular communication interface card 122 may independently perform cellular communication with at least one of the base station 200, an external device, and a server in a frequency band above 6 GHz supported by the corresponding NIC module according to cellular communication standards or protocols.

[0157] The unauthorized band communication interface card 123 transmits or receives radio signals with at least one of the base station 200, an external device, and a server by using a third band as an unauthorized band, and provides unauthorized band communication services based on instructions from the processor 110. The unauthorized band communication interface card 123 may include at least one NIC module that uses an unauthorized band. For example, the unauthorized band may be a band of 2.4 GHz or 5 GHz. At least one NIC module of the unauthorized band communication interface card 123 may perform wireless communication with at least one of the base station 200, an external device, and a server independently or dependently according to an unauthorized band communication standard or protocol of a band supported by the corresponding NIC module.

[0158] The memory 130 stores control programs used in the UE 100 and various data therefor. Such control programs may include prescribed programs required to perform wireless communication with at least one of the base station 200, an external device, and a server.

[0159] Next, the user interface 140 includes various input / output means provided in the UE 100. In other words, the user interface 140 may receive user input by using various input means, and the processor 110 may control the UE 100 based on the received user input. In addition, the user interface 140 may perform output based on instructions from the processor 110 by using various output means.

[0160] Next, the display unit 150 outputs various images on a display screen. The display unit 150 may output various display objects, such as content executed by the processor 110 or a user interface, based on control instructions from the processor 110.

[0161] In addition, the base station 200 according to an embodiment of the present disclosure may include a processor 210, a communication module 220, and a memory 230.

[0162] First, the processor 210 may execute various instructions or programs and process internal data of the base station 200. In addition, the processor 210 may control the overall operation of each unit in the base station 200 and control the transmission and reception of data between the units. Here, the processor 210 may be configured to perform operations according to the embodiments described in the present disclosure. For example, the processor 210 may signal a time slot configuration and perform communication according to the signaled time slot configuration.

[0163] Next, the communication module 220 may be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 120 may include multiple network interface cards in an internal or external form, such as cellular communication interface cards 221 and 222 and an unlicensed band communication interface card 223. In the drawings, the communication module 220 is shown as an overall integrated module, but different from the drawings, each network interface card can be independently arranged according to the circuit configuration or usage.

[0164] The cellular communication interface card 221 may transmit or receive radio signals with at least one of the base station 100, an external device, and a server using a mobile communication network and provide cellular communication services in a first band based on instructions from the processor 210. According to an embodiment, the cellular communication interface card 221 may include at least one NIC module using a band less than 6 GHz. At least one NIC module of the cellular communication interface card 221 may independently perform cellular communication with at least one of the base station 100, an external device, and a server in a band less than 6 GHz supported by the corresponding NIC module according to cellular communication standards or protocols.

[0165] The cellular communication interface card 222 may transmit or receive radio signals with at least one of the base station 100, an external device, and a server using a mobile communication network and provide cellular communication services in a second band based on instructions from the processor 210. According to an embodiment, the cellular communication interface card 222 may include at least one NIC module using a band of 6 GHz or higher. At least one NIC module of the cellular communication interface card 222 may independently perform cellular communication with at least one of the base station 100, an external device, and a server in a band of 6 GHz or higher supported by the corresponding NIC module according to cellular communication standards or protocols.

[0166] The unlicensed band communication interface card 223 transmits or receives radio signals with at least one of the base station 100, an external device, and a server using a third band that is an unlicensed band, and provides unlicensed band communication services based on instructions from the processor 210. The unlicensed band communication interface card 223 may include at least one NIC module using an unlicensed band. For example, the unlicensed band may be a band of 2.4 GHz or 5 GHz. At least one NIC module of the unlicensed band communication interface card 223 may perform wireless communication with at least one of the base station 100, an external device, and a server independently or dependently according to unlicensed band communication standards or protocols of the band supported by the corresponding NIC module.

[0167] Figure 11FIG. 0 is a block diagram of a UE 100 and a base station 200 according to an embodiment of the present disclosure, and the blocks shown separately are logically divided elements of the device. Accordingly, the foregoing elements of the device may be installed in a single chip or multiple chips according to the design of the device. In addition, a part of the configuration of the UE 100, for example, the user interface 140, the display unit 150, etc., may be selectively provided in the UE 100. In addition, the user interface 140, the display unit 150, etc. may be additionally provided in the base station 200 when necessary.

[0168] Meanwhile, regarding the configuration for delivering HARQ-ACK, the UE may send HARQ-ACK bits of the received PDSCH on an uplink control channel (e.g., PUCCH) or an uplink data channel (e.g., PUSCH). For example, the UE may schedule 1 transport block (TB) or 2 TBs for the base station for a downlink control channel (e.g., PDCCH) to schedule the PDSCH for the UE. When only 1 TB is scheduled, the UE should feedback 1-bit HARQ-ACK bits for the corresponding TB. When 2 TBs are scheduled, the UE should feedback 2-bit HARQ-ACK bits for each of the two TBs. There may be a determined order between the 2-bit HARQ-ACK bits and the 2 TBs to avoid misunderstanding between the base station and the UE. As a reference, 1 TB is sent when the multiple-input multiple-output (MIMO) transmission rank or layer is low, and 2 TBs are sent when the MIMO transmission rank or layer is high.

[0169] The component carrier described in the embodiments of the present invention may be used together with the term "cell". Although the description in the embodiments of the present invention focuses on carrier aggregation, in the case of a system using a TDD scheme, the component carrier may be considered to correspond to all component carriers of the subframe (or time slot) multiplexed by HARQ-ACK.

[0170] When a UE uses carrier aggregation in which multiple carriers are aggregated and transmitted, each component carrier can be configured with a different transmission scheme. That is, component carrier #0 can be configured with 1TB transmission, while component carrier #1 can be configured with 2TB transmission. When either self-carrier scheduling or cross-carrier scheduling is configured for the UE, the UE should decode the PDCCH by monitoring the component carrier on which the UE should monitor the PDCCH according to the scheme set for the UE, and should collect HARQ-ACKs for the TBs transmitted via PDSCH in each component carrier, and transmit such HARQ-ACKs on the PUCCH (or PUSCH). However, the UE may not be able to decode the PDCCH scheduled for some of the component carriers configured by the base station (this is referred to as the occurrence of discontinuous transmission (DTX)), and may only collect the HARQ-ACKs of the component carriers for which decoding has been successful, excluding the HARQ-ACKs of said some component carriers, and transmit such HARQ-ACKs on the PUCCH (or PUSCH). In this case, there may be a misunderstanding in the interpretation of the HARQ-ACK feedback between the base station and the UE.

[0171] To solve this problem, 3GPP New Radio (NR) supports a semi-static HARQ-ACK codebook (type-1 HARQ-ACK codebook) and a dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook).

[0172] Figure 12 It is a diagram regarding the process of generating a semi-static HARQ-ACK codebook according to an embodiment of the present invention.

[0173] As described above, the semi-static HARQ-ACK codebook indicates that the UE and the base station pre-agree on the length of the HARQ-ACK codebook and for which PDSCH each bit is used as ACK / NACK information, and no additional signaling is required. Here, the set of PDSCH candidates included in the semi-static HARQ-ACK codebook is referred to as the DL association set (or PDSCH candidate set). Embodiments of the present invention relate to a method for determining the DL association set (or PDSCH candidate set) in a semi-static HARQ-ACK codebook.

[0174] As an embodiment of the present invention, the UE uses the following information when determining the DL association set (or PDSCH candidate set). First, the above information includes all possible K1 values indicated to the UE. Here, the K1 value indicates the difference between the last time slot in which the PDSCH is transmitted (or scheduled) and the time slot in which the PUCCH is transmitted. The fallback DCI (or DCI format 1_0) can take a value from {1, 2, 3, 4, 5, 6, 7, 8} as the K1 value, and the non-fallback DCI (or DCI format 1_1 or DCI format 1_2) can be configured with up to eight K1 values through the RRC signal. Second, the above information includes all possible K0 values indicated to the UE and the combination of the starting symbol and length of the PDSCH within a time slot. Here, the starting symbol and length of the PDSCH are jointly encoded and indicated by the starting and length indicator value (SLIV). Here, the K0 value indicates the difference between the time slot in which the PDCCH is transmitted and the time slot in which the PDSCH scheduled by the PDCCH is transmitted. Third, the above information includes semi-static DL / UL configuration information. The semi-static DL / UL configuration is the configuration information of the time slots configured by the cell-specific RRC signal or the UE-specific RRC signal, and can indicate whether each symbol is a DL symbol, a UL symbol, or a flexible symbol. Fourth, the above information includes CORESET and search space configuration information. The CORESET and search space configuration information informs at which position in which time slot the PDCCH can be transmitted. Fifth, the above information includes PDSCH repetition information. The PDSCH repetition information can be configured with a value of 1, 2, 4, or 8 through the RRC signal, and according to the configured value, the same PDSCH is repeatedly transmitted in the time slot. Here, the starting symbol and length of the PDSCH are the same in each time slot. For reference, when the PDSCH repetition information is greater than 1, this can be expressed as reception through time slot aggregation.

[0175] Reference Figure 12 , as an embodiment of the present invention, when the UE is configured to receive through time slot aggregation, the steps for determining the DL association set (or PDSCH candidate set) can be configured as follows. Here, it is assumed that the PUCCH is located in time slot n. In addition, the PDSCH repetition value is N rep .

[0176] First, in the first step, the UE can confirm the following for a K1 value (denoted as K 1,k ) and a K0 and SLIV value (K 0,l , SLIV l ). If in at least one of the time slots n - K 1,k , time slot n - K 1,k - 1,..., time slot n - K 1,k - (N rep - 1) there is a PDSCH transmitted through SLIVl There is no UL symbol in the indicated symbol position, and in time slot n-K 1,k -(N rep -1)-K0, if there is a CORESET and search space for monitoring the PDCCH, it can be assumed that the PDSCH allocated to the corresponding (K 1,k ,K 0,l ,SLIV l ) can be transmitted and included in the DL association set (or PDSCH candidate set). Otherwise, it is assumed that the PDSCH allocated to (K 1,k ,K 0,l ,SLIV l ) cannot be transmitted, and the UE cannot include this PDSCH in the DL association set (or PDSCH candidate set). For example, when at least one UL symbol overlaps with the symbol allocated with the PDSCH symbol in all time slots, the PDSCH cannot be transmitted.

[0177] In the second step, among the combinations that may be included in the DL association set (or PDSCH candidate set) in the first step, the UE can confirm the following regarding multiple K1 values represented as (K 1,k ) and multiple K0 and SLIV values (K 0,l 、SLIV l ).

[0178] Here, for the sake of convenience of expression, the index numbers of the combinations that may be included in the DL association set (or PDSCH candidate set) in the first step are n = 1, 2,....

[0179] If for combination n in the combinations that may be included in the DL association set (or PDSCH candidate set) in the first step, the PDSCH allocation of other combinations m = n + 1,... overlaps with the PDSCH allocation of combination n in at least one time slot for at least one symbol, then combination m is combined with combination n as one, and combination m is excluded. For n = 1, 2,..., the above scheme can be executed sequentially.

[0180] The dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook) is a scheme for detecting DTX according to the downlink assignment index (DAI). The PDCCH for scheduling each PDSCH includes a counter DAI and a total-DAI. The counter DAI indicates the number of scheduled PDSCHs from component carrier #0 to the current component carrier. The total-DAI indicates the number of PDSCHs scheduled for all component carriers. By successfully decoding the PDCCH, the UE can identify the number of transmissions of the PDSCH scheduled by the PDCCH, and can send HARQ-ACK in the corresponding order.

[0181] ReferenceFigure 15 When the PDSCH is transmitted from the base station to a UE that can combinatorially use up to eight component carriers on component carriers #0, #1, #3, #4, #5, and #7, the (counter DAI, total DAI) values of component carrier #0 are (0, 5), the (counter DAI, total DAI) values of component carrier #1 are (1, 5), the (counter DAI, total DAI) values of component carrier #3 are (2, 5), the (counter DAI, total DAI) values of component carrier #4 are (3, 5), the (counter DAI, total DAI) values of component carrier #5 are (4, 5), and the (counter DAI, total DAI) values of component carrier #1 are (5, 5). When the UE fails to decode the PDCCH corresponding to component carrier #3, the UE can identify a reception failure of a PDSCH through the counter DAI value of the PDCCH corresponding to component carrier #4. When the UE fails to decode the PDCCH corresponding to component carrier #7, the UE can identify that a PDSCH has been scheduled but not received after component carrier #5 through the counter DAI value and the total DAI value of the PDCCH corresponding to component carrier #5.

[0182] The problem to be solved by the present invention is to provide a method for transmitting a PUCCH including at least two HARQ-ACK information in one time slot. This operation is necessary for quickly receiving retransmissions from the base station by transmitting HARQ-ACK as quickly as possible to support services that require low latency and high reliability, such as URLLC services. In 3GPP NR Release 15, a PUCCH including at most one HARQ-ACK information can be transmitted in one time slot. Therefore, the UE should transmit HARQ-ACK responses for different PDSCHs in different time slots or should multiplex the HARQ-ACK responses in one PUCCH to transmit the HARQ-ACK responses. As described above, in order to reduce latency, it is not appropriate to transmit HARQ-ACK in different time slots, and when transmitting by multiplexing with the same PUCCH, a coverage problem of the PUCCH, that is, a reliability problem, may occur. Therefore, a method for transmitting a PUCCH including multiple HARQ-ACK information in one time slot is being discussed in 3GPP NR Release 16. The present invention discloses this method.

[0183] 1. PDSCH group indicator

[0184] The UE may receive an indication of information on the group indicator (or group ID) of the PDSCH on the PDCCH (or DCI) scheduling the PDSCH, or may infer the information from a value configured by RRC or a value of another field transmitted on the DCI. Specific indication and inference methods will be described later. For convenience, the above indicator is referred to as the PDSCH group indicator. The UE may generate a HARQ-ACK codebook by multiplexing the HARQ-ACKs of the PDSCHs indicated by the same PDSCH group indicator, and may then always transmit on the same PUCCH. That is, if different PDSCH group indicators are used, different PUCCHs may be transmitted in one time slot.

[0185] Figure 13 FIG. is a diagram illustrating a method for transmitting a PUCCH according to a PDSCH group indicator according to an embodiment of the present invention.

[0186] Reference Figure 13 , the PDSCH group indicator may have two values, i.e., 0 or 1, and in this case, at most two different PUCCHs may be transmitted in one time slot. In Figure 13 's embodiment, the PUCCH for transmitting the HARQ-ACKs of the two PDSCHs with the PDSCH group indicator value of 0 may be determined according to the PUCCH resource indicator (PRI) indicated by the later-scheduled PDCCH (or DCI) among the two PDSCHs with the PDSCH group indicator value of 0. In addition, in Figure 13 's embodiment, the PUCCH for transmitting the HARQ-ACKs of the two PDSCHs with the PDSCH group indicator value of 1 may be determined according to the PUCCH resource indicator (PRI) indicated by the later-scheduled PDCCH (or DCI) among the two PDSCHs with the PDSCH group indicator value of 1. If the PUCCH resources indicated by the two PRI values do not overlap, the UE may transmit two PUCCHs in one time slot.

[0187] To transmit X PUCCHs in one time slot, the PUCCH group indicator should indicate one value among 0, 1, …, X−1. Therefore, B = ceil(log2(X)) bits are required. These B bits may be explicitly indicated by the PDCCH (or DCI) or may be determined depending on other factors. The implicit determination scheme may be similar to the scheme for implicitly determining the HARQ-ACK multiplexing indicator value, as described below.

[0188] When the PDSCH group indicator is configured such that multiple PUCCHs are transmitted in one time slot, the UE shall determine the HARQ-ACK bits to be included in each PUCCH, i.e., the HARQ-ACK codebook. In particular, if the UE is configured to use a HARQ-ACK codebook (Type-1 HARQ-ACK codebook according to 3GPP TS38.213), the UE shall generate a semi-static HARQ-ACK codebook to be transmitted on the PUCCH corresponding to the corresponding PDSCH group indicator. If the semi-static HARQ-ACK codebooks corresponding to each PDSCH group indicator are generated independently without additional definition, each PUCCH transmits a semi-static HARQ-ACK codebook of the same size in the same time slot, and thus the coverage of the uplink PUCCH is limited. Therefore, the present invention proposes the following for a method of reducing the size of the semi-static HARQ-ACK codebooks transmitted on the PUCCHs corresponding to different PDSCH group indicators in one time slot.

[0189] - As a first method, the UE may divide the time slot into two halves, and may include in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0 the PDSCH candidates that may be transmitted in the first half, and may include in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1 the PDSCH candidates that may be transmitted in the second half. In other words, by using the time domain information occupied by the PDSCH candidates, it can be determined which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the PDSCH is to be included.

[0190] - As a second method, the UE may determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook of the HARQ-ACK of the PDSCH to be included therein according to the K1 value indicated by the PDCCH (or DCI). For example, the HARQ-ACK of the PDSCH indicated by four of the eight smaller K1 values may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and the HARQ-ACK of the PDSCH indicated by the remaining four larger K1 values may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0.

[0191] - As a third method, the UE can determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the HARQ-ACK of the PDSCH to be included is located according to the length (occupied symbols) value of the PDSCH indicated by the PDCCH (or DCI). For example, when the length of the PDSCH is 2 or 4, the HARQ-ACK of the PDSCH can be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and the HARQ-ACK of at least 7 PDSCHs can be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0.

[0192] - As a fourth method, the UE can determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the HARQ-ACK of the PDSCH to be included is located according to the PDSCH mapping type indicated by the PDCCH (or DCI). For example, if PDSCH mapping type A is indicated, the HARQ-ACK of the PDSCH can be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and if PDSCH mapping type B is indicated, the HARQ-ACK of the PDSCH can be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1.

[0193] - As a fifth method, the UE can determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the HARQ-ACK of the PDSCH to be included is located according to the index of the time domain resource allocation field indicated by the PDCCH (or DCI). For example, the HARQ-ACK of the PDSCH with an indicated index of 0 to 7 (bits 0000 to 0111) can be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and the HARQ-ACK of the PDSCH with an indicated index of 8 to 15 (bits 1000 to 1111) can be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1.

[0194] - As another method, when the base station configures a semi-static HARQ-ACK codebook for a specific PDSCH_group_indicator for the UE, the base station can configure the number of HARQ-ACKs (or PDSCHs) required per time slot. For example, when two HARQ-ACK bits are configured per time slot, the UE can generate a semi-static HARQ-ACK codebook with a maximum of 2 bits per time slot when generating the semi-static HARQ-ACK codebook for a specific PDSCH_group_indicator. In other words, the UE expects to receive a maximum of two PDSCHs (1 bit per PDSCH) indicated by a specific PDSCH_group_indicator in one time slot. The number of HARQ-ACKs (or PDSCHs) required per time slot can be configured with different values in the semi-static HARQ-ACK codebooks corresponding to different PDSCH_group_indicators.

[0195] - As another method, the UE can configure the HARQ-ACK codebook for a specific PDSCH_group_indicator with a semi-static HARQ-ACK codebook scheme and can configure the HARQ-ACK codebook for another specific PDSCH_group_indicator with a dynamic HARQ-ACK codebook scheme.

[0196] - As another method, when the UE receives only one PDSCH with a specific PDSCH group indicator value (i.e., when there is no HARQ-ACK for another PDSCH to be multiplexed), the UE can send only the HARQ-ACK for the received one PDSCH on the PUCCH.

[0197] - As another method, when the UE receives the configuration of the PUCCH resource indicator (PRI) from the base station, the UE may receive the configuration of the PDSCH group indicator corresponding to each PRI value. For example, when the UE receives the configuration of 16 PUCCHs and PRI values (here 0, 1,..., 15), and when the number of PDSCH group indicators is four (0, 1, 2, 3), the base station may receive the values 0, 1, 2, or 3 as the PDSCH group indicator values when receiving the configuration and PRI value of each PUCCH. That is, the PDSCH group indication value 0 may be configured for the PRI values 0, 1, 2, 3, the PDSCH group indication value 1 may be configured for the PRI values 4, 5, 6, 7, the PDSCH group indicator value 2 may be configured for the PRI values 8, 9, 10, and 11, and the PDSCH group indicator value 3 may be configured for the PRI values 12, 13, 14, and 16. The UE may identify the PDSCH group indicator value through the PRI value of the DCI scheduling the PDSCH. In the above embodiment, when the PRI value of the DCI is 10, the UE may identify 2 as the PDSCH group indicator value.

[0198] Another problem to be solved by the present invention relates to a scheme for transmitting PUCCH when the PUCCH resources indicated by different PDSCH group indicators overlap.

[0199] Figure 14 FIG. is a diagram illustrating a situation where a conflict occurs when transmitting PUCCH according to a PDSCH group indicator according to an embodiment of the present invention.

[0200] Reference Figure 14 , when the PUCCH resources corresponding to the PDSCH group indicator 0 of one UE and the PUCCH resources corresponding to the PDSCH group indicator 1 overlap, the UE cannot transmit two PUCCHs simultaneously. Here, the UE may discard one of the two PUCCHs and transmit the other PUCCH, or may transmit the HARQ-ACK codebooks of the two PUCCHs on one PUCCH. The present invention specifically proposes the above operations.

[0201] In the operation of discarding one of the two PUCCHs and transmitting the other PUCCH, which PUCCH should be transmitted is determined as follows.

[0202] - As a first embodiment, the UE transmits the PUCCH corresponding to the PDSCH_group_indicator indicated by the most recently received PDCCH (or DCI), and discards the PUCCH corresponding to the PDSCH_group_indicator that is not the case without transmission.

[0203] - As a second embodiment, the PUCCH with a lower code rate value (higher reliability) among two overlapping PUCCHs is transmitted, and the PUCCH that is not in this case is discarded without being transmitted.

[0204] - As a third embodiment, the PUCCH of the earlier resource among two overlapping PUCCHs is transmitted, and the PUCCH of the later resource is discarded without being transmitted. Determining whether a resource is earlier or later can be based on the last symbol of the resource, and if the resources have the same last symbol, the resource with the earlier starting symbol can be determined as the earlier resource.

[0205] - As a fourth embodiment, the PUCCH that occupies a longer symbol among two overlapping PUCCHs can be transmitted, and the PUCCH that occupies a smaller symbol can be discarded without being transmitted.

[0206] - As another embodiment, the PUCCH with a smaller PUCCH resource indicator (PRI) value among two overlapping PUCCHs can be transmitted, and the PUCCH with a larger value can be discarded.

[0207] In the operation of transmitting the HARQ-ACK codebook of two PUCCHs on one PUCCH, the HARQ-ACK codebook can be created as follows.

[0208] - As a first embodiment, the UE can generate a large codebook by successively concatenating HARQ-ACK codebooks according to the order of the PDSCH_group_indicator values, and can transmit this codebook on one PUCCH resource.

[0209] - As a second embodiment, the UE can newly generate a codebook for the PDSCH candidates included in the overlapping PUCCHs (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates), and can transmit the HARQ-ACK codebook on one PUCCH resource. Alternatively, when generating a large codebook by successively concatenating HARQ-ACK codebooks according to the order of the PDSCH_group_indicator values, the UE can exclude the HARQ-ACK bits included in the earlier codebook from the later HARQ-ACK codebook. The advantage of the second embodiment is that when there are HARQ-ACK bits for one PDSCH candidate in both of the two overlapping PUCCHs in the first embodiment, these bits are not transmitted repeatedly.

[0210] The PDSCH group indicator with 1 bit can be included in the DCI that schedules the PDSCH, and if the PDSCH is included in a PDSCH group different from the previously transmitted PDSCH group, this 1 bit can be toggled. When toggling the value of the PDSCH group indicator, the UE can determine that the PDSCH is included in the new PDSCH group. That is, the PDSCH can be multiplexed not with the HARQ-ACK of the previous PDSCH group, but with the HARQ-ACK of the new PDSCH group. When the value of the PDSCH group indicator is not toggled, the UE can determine that the PDSCH is included in the previous PDSCH group. That is, the PDSCH can be multiplexed with the HARQ-ACK of the previous PDSCH group.

[0211] 2. Finer K1 granularity

[0212] The PDCCH (or DCI) that schedules the PDSCH can indicate a K1 value (PDSCH to HARQ_feedback timing indicator) to indicate in which time slot the HARQ-ACK of the PDSCH will be transmitted. The K1 value is the number of time slots between the time slot in which the scheduled PDSCH ends and the time slot in which the PUCCH on which the HARQ-ACK is transmitted is sent. Since the unit of the K1 value is a time slot, two or more PUCCHs cannot be sent within one time slot. The unit (or granularity) of the K1 value indicated by the DCI can be determined to be less than the unit of a time slot so that a PUCCH including one or more HARQ-ACKs can be sent within one time slot.

[0213] Figure 15 FIG. is a diagram illustrating a method for transmitting a PUCCH when the unit of K1 is set to a half time slot according to an embodiment of the present invention.

[0214] Reference Figure 15 , the unit of K1 can be determined to be a half time slot. That is, the K1 value is the number of half time slots between the half time slot in which the scheduled PDSCH ends and the half time slot in which the PUCCH on which the HARQ-ACK is transmitted is sent.

[0215] When the granularity of K1 is given as a sub - slot (or symbol set), the K1 value indicates the number of sub - slots between the sub - slot including the last symbol of the PDSCH and the sub - slot including the first symbol of the PUCCH. That is, if the K1 value is 0, this value indicates that the sub - slot including the last symbol of the PDSCH and the sub - slot including the first symbol of the PUCCH are the same sub - slot. As another embodiment, when the granularity of K1 is given as a sub - slot (or symbol set), the K1 value indicates the number of sub - slots between the last sub - slot of the slot including the last symbol of the PDSCH and the sub - slot including the first symbol of the PUCCH. That is, if the K1 value is 0, this value indicates that the last sub - slot of the slot including the last symbol of the PDSCH and the sub - slot including the first symbol of the PUCCH are the same sub - slot. As another embodiment, when the granularity of K1 is given as a sub - slot (or symbol set), the K1 value indicates the number of sub - slots between the foremost sub - slot among the sub - slots after the T proc,1 time of the last symbol of the PDSCH and the sub - slot including the first symbol of the PUCCH. Here, T proc,1 indicates the minimum time taken to receive the PDSCH and transmit a valid HARQ - ACK. This value is indicated in TS38.214.

[0216] Another problem to be solved by the present invention relates to a scheme for transmitting PUCCH when PUCCH resources indicated by different half - slots (or K1 units) overlap in one slot.

[0217] Figure 16 is a diagram illustrating a situation where a conflict occurs when transmitting PUCCH when the unit of K1 is set to a half - slot according to an embodiment of the present invention.

[0218] Refer to Figure 16 , when the PUCCH resources starting in the first half - slot of a UE overlap with the PUCCH resources starting in the second half - slot, the UE cannot transmit two PUCCHs simultaneously. Here, the UE can discard one of the two PUCCHs and transmit the other PUCCH, or can transmit the HARQ - ACK codebook of the two PUCCHs on one PUCCH. Embodiments of the present invention specifically propose the above operations.

[0219] In the operation of discarding one of the two PUCCHs and transmitting the other PUCCH, it is determined which PUCCH should be transmitted as follows.

[0220] - As a first embodiment, the UE transmits the PUCCH indicated by the most recently received PDCCH (or DCI), and discards the PUCCH that is not the case without transmission.

[0221] - As a second embodiment, the PUCCH with a lower code rate value (higher reliability) among two overlapping PUCCHs is transmitted, and the PUCCH that is not in this case is discarded without being transmitted.

[0222] - As a third embodiment, the PUCCH of the earlier resource among two overlapping PUCCHs is transmitted, and the PUCCH of the later resource is discarded without being transmitted. Determining whether a resource is earlier or later can be based on the last symbol of the resource, and if resources have the same last symbol, the resource with the earlier starting symbol can be determined as the earlier resource.

[0223] - As a fourth embodiment, the PUCCH that occupies a longer symbol among two overlapping PUCCHs can be transmitted, and the PUCCH that occupies a smaller symbol can be discarded without being transmitted.

[0224] - As another embodiment, the PUCCH with a smaller PUCCH resource indicator (PRI) value among two overlapping PUCCHs can be transmitted, and the PUCCH with a larger value can be discarded.

[0225] In the operation of transmitting the HARQ-ACK codebook of two PUCCHs on one PUCCH, the HARQ-ACK codebook can be created as follows.

[0226] - As a first embodiment, the UE can generate a large codebook by sequentially connecting HARQ-ACK codebooks in chronological order (i.e., the HARQ-ACK codebook indicated to be transmitted in the first half of the time slot is located before the HARQ-ACK codebook indicated to be transmitted in the second half of the time slot), and can transmit the codebook on one PUCCH resource.

[0227] - As a second embodiment, the UE can newly generate a codebook for the PDSCH candidates included in the overlapping PUCCHs (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates), and can transmit the HARQ-ACK codebook on one PUCCH resource. Alternatively, when generating a large codebook by sequentially connecting HARQ-ACK codebooks in chronological order, the UE can exclude the HARQ-ACK bits included in the earlier codebook from the later HARQ-ACK codebook. The advantage of the second embodiment is that when there are HARQ-ACK bits for one PDSCH candidate in both of the two overlapping PUCCHs in the first embodiment, these bits are not repeatedly transmitted.

[0228] 3. HARQ-ACK multiplexing indicator

[0229] As an embodiment of the present invention, the UE may receive an indication of information on whether to multiplex the HARQ-ACK of the PDSCH with the HARQ-ACK of another PDSCH from the PDCCH (or DCI) that schedules the PDSCH. For convenience, the above indicator is referred to as the HARQ-ACK multiplexing indicator. The HARQ-ACK multiplexing indicator may be determined by 1 bit. In the case of 1 bit, 0 may indicate that the HARQ-ACK of the PDSCH is not multiplexed with the HARQ-ACK of another PDSCH for transmission, and 1 indicates that the HARQ-ACK of the PDSCH is multiplexed with the HARQ-ACK of another PDSCH for transmission. Here, not multiplexing with the HARQ-ACK of another PDSCH for transmission means that the PUCCH transmitted by including the HARQ-ACK of the PDSCH does not include the HARQ-ACK information of another PDSCH. Therefore, the PUCCH includes 2-bit HARQ-ACK when configured to transmit 1 bit (or 2 transmission blocks of the PDSCH), and the HARQ-ACK may be transmitted in one of the PUCCH formats 0 and PUCCH format 1 according to the bit size. Multiplexing with the HARQ-ACK of another PDSCH for transmission means that the PUCCH transmitted by including the HARQ-ACK of the PDSCH may include the HARQ-ACK information of another PDSCH. When transmitted by multiplexing with the HARQ-ACK of another PDSCH, the HARQ-ACK codebook is generated using the dynamic HARQ-ACK codebook or semi-static HARQ-ACK codebook scheme, and the HARQ-ACK codebook is transmitted on the PUCCH.

[0230] Figure 17 FIG. is a diagram illustrating a method for transmitting a PUCCH according to a HARQ-ACK multiplexing indicator according to an embodiment of the present invention.

[0231] Reference Figure 17, the UE sends the HARQ-ACK information of two PDSCHs with a HARQ-ACK multiplexing indicator value of 1 through a PUCCH. Further, the HARQ-ACK information of two PDSCHs with a HARQ-ACK multiplexing indicator value of 0 is sent through the corresponding PUCCH resources. Here, the PUCCH resources of the PDSCH with a HARQ-ACK multiplexing indicator value of 0 are indicated by the PRI value that schedules the PDSCH. Here, when the PUCCHs of the HARQ-ACKs of different PDSCHs used to send the HARQ-ACK multiplexing indicator value of 0 (impossible to multiplex with the HARQ-ACK of another PDSCH) overlap in the same symbol, simultaneous transmission is not possible. In this case, the HARQ-ACK information of the two PUCCHs can be multiplexed into one PUCCH for transmission. As another method, the HARQ-ACK of the later-scheduled PDSCH (i.e., when the PDCCH that schedules the PDSCH starts later or ends later) can be prioritized for sending the PUCCH of the PDSCH, and the other overlapping PUCCH may not be sent. As another method, the UE may not expect the two PUCCHs to overlap in one symbol.

[0232] As another embodiment of the present invention, even when 0 is indicated as the HARQ-ACK multiplexing indicator value (impossible to multiplex with the HARQ-ACK of another PDSCH), HARQ-ACK multiplexing can be partially possible. For example, if two PDSCHs with 0 indicated as the HARQ-ACK multiplexing indicator value are indicated to be sent on the same PUCCH resource (or have the same PUCCH resource indicator (PRI) value or overlap in at least one symbol), the HARQ-ACKs of the two PDSCHs can be multiplexed and sent. Here, the HARQ-ACK bits of the later-scheduled PDSCH are located after the HARQ-ACK bits of the earlier-scheduled PDSCH.

[0233] Figure 18 FIG. is a diagram illustrating a HARQ-ACK multiplexing method using PRI when sending a PUCCH according to a HARQ-ACK multiplexing indicator according to an embodiment of the present invention.

[0234] Reference Figure 18 of (a), when the PDSCH with 0 indicated as the HARQ-ACK multiplexing indicator value has the same PRI value i, the UE can send the HARQ-ACKs of the two PDSCHs on the PUCCH resource corresponding to PRI = i.

[0235] Reference Figure 18In (b) thereof, when the PDSCHs with 0 indicated as the HARQ-ACK multiplexing indicator value have different PRI values, the UE may send each HARQ-ACK information on the PUCCH resource corresponding to the respective PRI value.

[0236] The PUCCH resources for sending the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value 1 and the PUCCH resources for sending the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value 0 may overlap. As a PUCCH transmission method for such a case, according to an embodiment of the present invention, the UE may always prioritize and send the PUCCH for sending the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value 0, and may discard the PUCCH for sending the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value 1. As another embodiment, if the last symbol of the PUCCH for sending the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value 1 ends before or at the same time as the last symbol of the PUCCH for sending the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value 0 ends, the UE may append the HARQ-ACK bits of the PDSCH with the HARQ-ACK multiplexing indicator value 0 to the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value 1 and send it on the PUCCH resource of the PDSCH with the HARQ-ACK multiplexing indicator value 1.

[0237] Although 1 bit is used for convenience to represent the HARQ-ACK multiplexing indicator, the indicator may be implicitly indicated as follows.

[0238] - As a first method, the HARQ-ACK multiplexing indicator may be determined according to the RNTI. For example, if the PDCCH (or DCI) scheduling the PDSCH is scrambled with the C-RNTI, the HARQ-ACK multiplexing indicator of the PDSCH may be determined to have a value of 1 (i.e., multiplexing with the HARQ-ACK information of another PDSCH is possible), and when the PDCCH (or DCI) scheduling the PDSCH is scrambled with a specific RNTI (e.g., the RNTI for the URLLC service) instead of the C-RNTI, the HARQ-ACK multiplexing indicator of the PDSCH may be determined to have a value of 0 (multiplexing with the HARQ-ACK of another PDSCH is not possible).

[0239] - As a second method, the HARQ-ACK multiplexing indicator can be determined according to the K1 value included in the PDCCH (or DCI). Here, the K1 value indicates the time interval between the scheduled PDSCH and the HARQ-ACK of the PDSCH. Therefore, generally speaking, the PDSCH of the URLLC service requires a quick indication of HARQ-ACK. Therefore, when the K1 value is less than a specific K1 value, the HARQ-ACK multiplexing indicator can be determined to be 0. Here, the specific K1 value can be determined in time slot units (e.g., 1 time slot or 2 time slots) or absolute time units (e.g., 0.5 milliseconds or 0.25 milliseconds). Alternatively, a specific value among the K1 values can be determined, and the HARQ-ACK multiplexing indicator can always be determined to be 0 when indicating this value. That is, when the UE receives the indication of this value, the UE can send only the HARQ-ACK for one PDSCH without generating a codebook.

[0240] - As a third method, the HARQ-ACK multiplexing indicator can be determined according to the modulation and coding scheme (MCS) value. Here, the MCS value indicates the code rate of the scheduled PDSCH. Generally speaking, the PDSCH for the URLLC service must be reliable. Therefore, when the code rate value is lower than a specific value, the HARQ-ACK multiplexing indicator can be determined to be 0. Also, for example, the HARQ-ACK multiplexing indicator can be determined according to the MCS table used by the PDCCH (or DCI). When a specific PDCCH (or DCI) uses an MCS table that provides higher reliability (lower code rate), the HARQ-ACK multiplexing indicator value of the PDCCH (or DCI) can be determined to be 0.

[0241] - As a fourth method, the HARQ-ACK multiplexing indicator can be determined to be 1 using a combination of specific values of other fields sent on the DCI.

[0242] - As a fifth method, the HARQ-ACK multiplexing indicator can be determined based on the search space (or CORESET) in which PDCCH (or DCI) has been detected. For example, the base station can additionally indicate to the UE the search space (or CORESET) for URLLC transmission. When the UE receives PDCCH (or DCI) in the above search space (or CORESET), the UE can determine that the HARQ-ACK multiplexing indicator is 0. When the UE receives PDCCH (or DCI) in another search space (or CORESET), the UE can determine the HARQ-ACK multiplexing indicator as 1. As another method, the UE can distinguish search spaces (or CORESETS) without additional explicit indication from the base station. For example, if the monitoring period of the search space (or CORESET) is shorter than a specific period, the search space (or CORESET) can be determined as the search space (or CORESET) for URLLC transmission. As an embodiment, the specific period can be 1 time slot.

[0243] - As a sixth method, the UE can determine the HARQ-ACK multiplexing indicator value by the control channel element (CCE) aggregation level of the received PDCCH. For example, if the CCE aggregation level exceeds a specific value, the UE can determine that the HARQ-ACK multiplexing indicator of the PDCCH is 0. Here, the specific CCE aggregation level value can be determined as 8 or 16.

[0244] - As a seventh method, the HARQ-ACK multiplexing indicator value can be determined by the DCI format (or DCI length). For example, if a compact DCI is configured for the UE, the UE can determine that the HARQ-ACK multiplexing indicator value of the PDSCH scheduled by the compact DCI is 0. Here, the compact DCI, as the DCI format for scheduling URLLC PDSCH, has a payload size smaller than that of the fallback DCI (DCI format 0_0 / 1_0).

[0245] As an eighth method, the HARQ-ACK multiplexing indicator value can be determined by the PUCCH resource indicator (PRI) value. Here, the PRI sent on the PUCCH (or DCI) indicates which PUCCH resource among the PUCCH resources configured for the UE by the base station is used. When the UE receives an indication of a specific value among the PRI values, the UE can determine the HARQ-ACK multiplexing indicator value as 0. This is because all configured PUCCH resources are not suitable for transmitting URLLC HARQ-ACK. For example, since PUCCH resources with more than 2 bits among the PUCCH resources are not suitable for transmitting URLLC HARQ-ACK, for the PRI indicating the corresponding PUCCH resource, the UE can determine the HARQ-ACK multiplexing indicator value as 1.

[0246] - As a ninth method, the HARQ-ACK multiplexing indicator value can be determined by the HARQ process number. For example, when a specific value among the HARQ process numbers is indicated, the UE can determine the HARQ-ACK multiplexing indicator value as 1 and send the HARQ-ACK only for one PDSCH.

[0247] - As a tenth method, the HARQ-ACK multiplexing indicator value can be determined by the PDSCH group indicator value. As described above, the PDSCH group indicator is introduced to send the HARQ-ACK on the same PUCCH resource. When the UE receives a specific value among the PDSCH group indicator values, the UE can determine the HARQ-ACK multiplexing indicator value as 1 and send the HARQ-ACK only for one PDSCH.

[0248] Another embodiment of the present invention relates to a method for a UE to interpret the K1 value.

[0249] As described above, the K1 value is the number of time slots between the time slot in which the scheduled PDSCH ends and the time slot in which the PUCCH on which the HARQ-ACK is sent is sent (where the time slot can be replaced by a specific unit smaller than the time slot). However, a processing time may occur when the UE actually receives and decodes the PDSCH and generates the PUCCH for sending the HARQ-ACK. Therefore, a specific K1 value, such as 0, cannot be indicated. The problem to be solved by the present invention is to define the value of K1, excluding the values that cannot be indicated.

[0250] - As a first embodiment of the present invention, when determining the K1 value, the UE can exclude the time slots that are completely included during the period from the last symbol of the PDSCH to the PDSCH processing time T proc,1 (the value defined in TS 38.214). That is, when the above time slots are called invalid time slots, the K1 value can be defined as the number of time slots between the time slot in which the scheduled PDSCH ends and the time slot in which the PUCCH on which the HARQ-ACK is sent, excluding the invalid time slots.

[0251] - As a second embodiment of the present invention, the UE cannot send the corresponding PUCCH on the semi-static DL symbols configured by the higher layer. Therefore, the UE can exclude the time slots configured only with semi-static DL symbols when determining the K1 value. Alternatively, the UE can exclude the time slots in which it is impossible to transmit all PUCCHs due to the semi-static DL symbols when determining the K1 value. That is, when the time slot in which the PUCCH resource indicated by the PRI overlaps with the semi-static DL symbol and thus the PUCCH cannot be sent is called an invalid time slot, the UE can define the K1 value as the number of time slots other than the invalid time slots between the time slot at the end of the scheduled PDSCH and the time slot on which the PUCCH for sending HARQ-ACK is sent.

[0252] The K1 or PRI field may not be configured to reduce the DCI overhead (the payload size of the DCI) in the PDCCH (or DCI) for scheduling URLLC. Embodiments of the present invention describe a method for determining the PUCCH resource when the K1 or PRI field is not configured.

[0253] - As a first embodiment of the present invention, when the K1 field (PDSCH to HARQ_feedback timing indicator field) is not configured, the time slot including the PUCCH resource may be the time slot in which it is possible to transmit the next PUCCH (indicated by the PRI), except for the time slots completely included during the PDSCH processing time T proc,1 (the value defined in TS 38.214).

[0254] - As a second embodiment of the present invention, when the K1 field (PDSCH to HARQ_feedback timing indicator field) is not configured, the time slot including the PUCCH resource may be the time slot in which the symbol indicated by the PRI does not overlap with the semi-static DL symbol.

[0255] - As a third embodiment of the present invention, when the PRI field is not configured, the PUCCH resource may be the earliest-ended PUCCH resource among the PUCCH resources configured in the time slot indicated by K1.

[0256] - As a fourth embodiment of the present invention, when the PRI field is not configured, the PUCCH resource may be the earliest-ended PUCCH resource among the PUCCH resources in the time slot indicated by K1, except for the PUCCH that does not satisfy the PDSCH processing time T proc,1 (the value defined in TS 38.214). Here, the PUCCH resources overlapping with the semi-static DL symbols may be excluded.

[0257] Figure 19FIG. is a diagram illustrating a method for transmitting PUCCH when the K1 and PRI fields are not present according to an embodiment of the present invention.

[0258] Reference Figure 19 , when both the K1 and PRI fields are not configured in the PDCCH (or DCI), the UE determines the PUCCH resource by the following method. In Figure 19 's embodiment, a total of 4 PUCCH resources are configured. The PUCCH resource #1 among the resources does not meet the processing time condition and thus can be excluded. Among the remaining PUCCH resources #2, #3, and #4, the earliest-ended PUCCH resource is #3, so the UE can determine #3 as the PUCCH resource for HARQ-ACK.

[0259] Another problem to be solved by the present invention relates to a design method of a dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook in TS 38.213). The base station can be configured to omit some DCI fields to increase the PDCCH reception success probability of the UE. Here, the meaning of the term "omit" includes being configured as 0 bits. For example, the base station can be configured to omit the counter DAI field among the DCI fields of the UE. As described above, in the dynamic HARQ-ACK codebook, the counter DAI field can be used not only to determine the position of the HARQ-ACK bits in the HARQ-ACK codebook but also to determine the size of the HARQ-ACK codebook. The UE should sort the HARQ-ACK bits of multiple PDSCHs in ascending order of the value of the counter DAI field to transmit these bits with the HARQ-ACK codebook. However, since the counter DAI field is omitted, a method for determining the order of the HARQ-ACK bits in the HARQ-ACK codebook is needed.

[0260] As a first embodiment of the present invention, the UE can determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook according to the reception time information of the PDCCH scheduling the PDSCH. More specifically, when the start symbol of the CORESET or search space including the PDCCH scheduling the first PDSCH precedes the start symbol of the CORESET or search space including the PDCCH scheduling the second PDSCH, the HARQ-ACK bits of the first PDSCH are located before the HARQ-ACK bits of the second PDSCH in the HARQ-ACK codebook. If the start symbols of the CORESET or search space are the same, the HARQ-ACK bits are located before the HARQ-ACK bits of the PDSCH scheduled by the PDCCH having the last symbol of the previous CORESET or search space.

[0261] As a second embodiment of the present invention, the UE may determine the order of HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook according to the time information of the PDSCH. More specifically, when the starting symbol of the first PDSCH is before the starting symbol of the second PDSCH, the HARQ-ACK bits of the first PDSCH are before the HARQ-ACK bits of the second PDSCH in the HARQ-ACK codebook. Here, the information about the starting symbol can be identified by the time domain resource assignment (TDRA) field of the PDCCH scheduling the PDSCH. If the starting symbols of the PDSCHs are the same, the HARQ-ACK bits of the PDSCH with the last symbol of the previous PDSCH are arranged in the front position. If the starting symbol and the last symbol are the same, the order of the HARQ-ACK bits in the HARQ-ACK codebook can be determined by another embodiment.

[0262] As a third embodiment of the present invention, the UE may determine the order of HARQ-ACK bits in the HARQ-ACK codebook according to the HARQ process ID (or HARQ process number) of the PDCCH scheduling the PDSCH. More specifically, when the HARQ process ID of the first PDSCH is called A in the PDCCH scheduling the first PDSCH, and the HARQ process ID of the second PDSCH is called B in the PDCCH scheduling the second PDSCH, the HARQ-ACK bits of the PDSCH with the smaller value among A and B can be before the HARQ-ACK bits of the PDSCH with the larger value in the HARQ-ACK codebook. That is to say, the position of the HARQ-ACK bits can be determined according to the ascending order of the HARQ process ID. Here, the UE assumes that the HARQ process IDs of the HARQ-ACKs sent with one HARQ-ACK codebook have different values. That is to say, the UE does not expect to generate the HARQ-ACK bits of the PDSCHs with the same HARQ process ID in one HARQ-ACK codebook.

[0263] As a fourth embodiment of the present invention, the UE may use the information of the cell from which it receives the PDCCH scheduling the PDSCH to determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook. Here, the cell information may be a cell index (or ID). The UE may be configured to monitor the PDCCH in multiple cells. In this case, the UE may receive different PDCCHs from different cells. Here, the UE may arrange the HARQ-ACK bits of the PDSCHs received from different cells in the HARQ-ACK codebook according to the ascending order of the indices of the cells from which it receives the PDCCHs scheduling the PDSCHs.

[0264] As a fourth embodiment of the present invention, the UE may use the information of the CORESET (or search space) of the PDCCH that receives the scheduling of the PDSCH to determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook. Here, the information of the CORESET (or search space) may be the index (or ID) of the CORESET (or search space). The UE may be configured to monitor the PDCCH in multiple CORESETs (or search spaces). In this case, the UE may receive different PDCCHs from different CORESETs (or search spaces). Here, the UE may arrange the HARQ-ACK bits of the PDSCH received from different CORESETs (or search spaces) in the HARQ-ACK codebook in ascending order of the index of the CORESET (or search space) of the PDCCH that receives the scheduling of the PDSCH.

[0265] As a sixth embodiment of the present invention, the UE may use the frequency domain information of the PDCCH that schedules the PDSCH to determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook. Here, the frequency domain information may be the lowest PRB index among the PRBs to which the PDCCH is allocated. Here, the index represents the common PRB index, and the index indicates the distance from point A in the frequency domain. Point A represents the reference frequency during the initial access procedure of the UE. According to TS 38.211, point A is as follows.

[0266] - offsetToPointA for the PCell downlink, where offsetToPointA represents the frequency offset between point A and the lowest subcarrier of the lowest resource block, which has the subcarrier spacing provided by the higher layer parameter subCarrierSpacingCommon and overlaps with the SS / PBCH block used by the UE for initial cell selection and represented in resource blocks, assuming a subcarrier spacing of 15 kHz for FR1 and 60 kHz for FR2;

[0267] - absoluteFrequencyPointA for all other cases, where absoluteFrequencyPointA represents the frequency position of point A, as represented in the ARFCN.

[0268] The UE can be configured to monitor multiple PDCCHs. In this case, the UE can receive different PDCCHs in different frequency domains. Here, the UE can arrange the HARQ-ACK bits of the PDSCHs received in different frequency domains in the HARQ-ACK codebook in ascending order of the lowest PRB index of the PDCCH scheduling the PDSCH. According to this scheme, when multiple PDCCHs are received from one CORESET (or search space) in the fifth embodiment, the order of the HARQ-ACK bits can be determined in the HARQ-ACK codebook.

[0269] The first to sixth embodiments described above can be combined to determine the order of the HARQ-ACK bits in the HARQ-ACK codebook. As a preferred combination of the present invention, the first embodiment and the third embodiment can be combined. Through this combination, the order of the HARQ-ACK bits can be determined first according to the time domain information of the PDCCH in the HARQ-ACK codebook, and when the order cannot be determined according to the time domain information, the order can be determined according to the HARQ process ID according to the third embodiment. As a preferred combination of the present invention, the first embodiment, the fourth embodiment, the fifth embodiment, and the sixth embodiment can be combined. Through this combination, the order of the HARQ-ACK bits can be determined first according to the time domain information of the PDCCH in the HARQ-ACK codebook, and when the order cannot be determined according to the time domain information, the order can be determined according to the cell information, and when the order cannot be determined according to the cell information, the order can be determined according to the information of the CORESET (or search space), and when the order cannot be determined according to the information of the CORESET (or search space), the order can be determined according to the frequency domain allocation information of the PDCCH.

[0270] Another problem to be solved by the present invention relates to the following situation, in which the PDCCH corresponding to one HARQ-ACK codebook of HARQ-ACK is included in two types, that is, DCI with a counter DAI field and DCI without a counter DAI field. In this case, in the HARQ-ACK codebook, the UE should determine the positions of the HARQ-ACK of the PDSCH scheduled by the DCI with a counter DAI field and the HARQ-ACK of the PDSCH scheduled by the DCI without a counter DAI field.

[0271] As an embodiment of the present invention, in the above case, the UE generates a first sub-HARQ-ACK codebook by collecting only HARQ-ACKs of PDSCHs scheduled by DCIs having a counter DAI field. Here, the position of the HARQ-ACK in the first sub-HARQ-ACK codebook is determined using the value of the counter DAI field (i.e., the position is determined according to the ascending order of the counter DAI). In addition, the UE generates a second sub-HARQ-ACK codebook by collecting only HARQ-ACKs of PDSCHs scheduled by DCIs without a counter DAI field. Here, a combination of the first to sixth embodiments can be used to determine the position of the HARQ-ACK in the second sub-HARQ-ACK codebook. The UE can generate a HARQ-ACK codebook by continuously combining the first sub-HARQ-ACK codebook and the second sub-HARQ-ACK codebook (i.e., making the first bit of the second sub-HARQ-ACK codebook follow the last bit of the first sub-HARQ-ACK codebook). This scheme may increase the complexity of the UE because the two sub-HARQ-ACK codebooks should be generated in different ways.

[0272] As another embodiment of the present invention, in the above case, even for a DCI having a counter DAI field, the UE can ignore the counter DAI field. That is, it can be assumed that all DCIs are DCIs without a counter DAI field, and a combination of the first to sixth embodiments can be used to determine the position of the HARQ-ACK bit in the HARQ-ACK codebook.

[0273] Another aspect of the present invention relates to a method for reducing the payload size of a DCI. Similar to the above method of not including the K1 or PRI field to reduce DCI overhead, another DCI field may not be included or only some options indicated by the DCI field may be included. Here, when only some options (e.g., N options) indicated by the DCI field are included, the bit size of the DCI field is ceil(log2(N)). However, if N is not shown as a power of 2, the 2^X - N code points of the corresponding DCI field cannot be used. Here, X is the minimum value among the integers satisfying the condition that 2^X is equal to or greater than N. Therefore, in order to utilize it more effectively, joint coding of different DCI fields is required.

[0274] As an embodiment of the present invention, assume that the j-th DCI field includes Y(j) options (option 0, option 1, option...). After receiving a DCI from the base station, the UE can obtain the order of the options in the j-th DCI field from the following equation. Here, the order starts from the 0-th (i.e., the foremost option is the 0-th).

[0275] Field(j) = floor(X / Z(j)) mod Y(j)

[0276] where, for j > 1, and and for j = 1, Z(1) = 1. Additionally, DCI_length is the length of the DCI, b k represent the received DCI in binary. That is, according to the above equations, the option corresponding to Field(j) (the Field(j)-th option) can be selected from the j-th DCI.

[0277] For example, the following table relates to the case where the DCI includes three fields, and each field includes three options. When calculating bits for each DCI field, 6 bits are required because each of the three fields occupies 2 bits. However, when using the proposed scheme, 5 bits are sufficient. In Table 4 below, 11011 to 11111 can be reserved.

[0278] [Table 4]

[0279]

[0280]

[0281] For example, when the UE receives 01100 as the indication of the DCI, the UE can obtain Field(1) = 0, Field(2) = 1, Field(3) = 1. That is, it can be understood that the Field(1) = 0-th option is indicated in the first DCI field, the Field(2) = 1-th option is indicated in the second DCI field, and the Field(3) = 1-th option is indicated in the third DCI field.

[0282] Another problem to be solved by the present invention relates to a method for dividing a time slot into sub - time slots. For example, when a time slot configured with 14 symbols is divided into two sub - time slots, each sub - time slot can be configured with 7 consecutive symbols. The first sub - time slot can be configured with the first 7 symbols of the time slot, and the second sub - time slot can be configured with the last 7 symbols of the time slot. As another example of the present invention, when a time slot configured with 14 symbols is divided into two sub - time slots, the first sub - time slot can be configured with the symbols with odd numbers in the time slot, and the second sub - time slot can be configured with the symbols with even numbers in the time slot. Generally speaking, by using the first method to divide a time slot configured with K symbols into N sub - time slots, (K mod N) sub - time slots can be configured with floor(K / N)+1 consecutive symbols, and N-(K mod N) sub - time slots can be configured with floor(K / N) consecutive symbols. Among the N sub - time slots, the (K mod N) sub - time slots with one more symbol can be located at the front of the time slot, and the N-(K mod N) sub - time slots with one less symbol can be located at the rear of the time slot. Among the N sub - time slots, the N-(K mod N) sub - time slots with one less symbol can be located at the very front of the time slot, and the (K mod N) sub - time slots with one more symbol can be located at the rear of the time slot. Among the N sub - time slots, the (K mod N) sub - time slots with one more symbol and the N-(K mod N) sub - time slots with one less symbol can be alternately positioned. Generally speaking, by using the second method to divide a time slot configured with K symbols into N sub - time slots, the nth sub - time slot can be configured with the floor(K / N)*i + n symbols (i = 0, 1,...).

[0283] As another method, the UE can divide sub - time slots through the time - domain resource allocation information of the configured PDSCH. For example, the sub - time slots can be divided according to the position order of the last symbol of the PDSCH in the time - domain resource allocation information of the PDSCH. The last symbol up to the last symbols of multiple PDSCHs with the earliest order can be divided into the first sub - time slot. Continuously, the above - mentioned scheme can be used to divide the remaining part.

[0284] According to another method, the UE can divide sub - time slots through the information of the symbols occupied by the configured PUCCH. For example, the sub - time slots can be divided according to the position order of the last symbol of the PUCCH in the symbol information occupied by the PUCCH. The last symbol up to the last symbols of the first A PUCCHs with the earliest order can be divided into the first sub - time slot. Continuously, the above - mentioned scheme can be used to divide the remaining part.

[0285] Another problem to be solved by the present invention relates to a method for generating a semi - static HARQ - ACK codebook when the K1 granularity is configured as a sub - time slot. More specifically, the problem to be solved is as follows.

[0286] Figure 20 It is a diagram showing PDSCH candidates for time slot configuration.

[0287] Reference Figure 20 , assume that there are three PDSCH candidates in a time slot. PDSCH candidate #1 is included in the first sub - time slot (here, whether a PDSCH candidate is included is determined by whether the last symbol of the PDSCH candidate is included). PDSCH candidate #2 and PDSCH candidate #3 are included in the second sub - time slot. In addition, PDSCH candidate #1 and PDSCH candidate #2 overlap in the same symbol, and PDSCH candidate #3 does not overlap with other PDSCH candidates. When only one PDSCH can be received in the same symbol, the maximum number of PDSCH candidates that a UE can receive simultaneously within the corresponding time slot is two. For example, the receivable cases are {PDSCH candidate #1}, {PDSCH candidate #2}, {PDSCH candidate #3}, {PDSCH candidate #1, PDSCH candidate #3}, and {PDSCH candidate #2, PDSCH candidate #3}. Based on this, the number of HARQ - ACK bits that the UE should include in the semi - static HARQ - ACK codebook for the PDSCH candidates in the corresponding time slot is 2. (Here, assume that one PDSCH candidate sends 1 bit of HARQ - ACK) When the granularity of K1 is given as a half - time slot, the generation of the semi - static HARQ - ACK codebook for each half - time slot is described below. Since the combination of PDSCHs that can be received in the first half - time slot is {PDSCH candidate #1}, at most one PDSCH can be received. Therefore, for this half - time slot, 1 bit of HARQ - ACK should be included in the semi - static HARQ - ACK codebook. Since the combination of PDSCHs that can be received in the second half - time slot is {PDSCH candidate #2}, {PDSCH candidate #3}, and {PDSCH candidate #2, PDSCH candidate #3}, at most two PDSCHs can be received. Therefore, for this half - time slot, 2 bits of HARQ - ACK should be included in the semi - static HARQ - ACK codebook. Therefore, for one time slot, a total of 3 bits of HARQ - ACK are included in the semi - static HARQ - ACK codebook. It can be understood that compared with the case where the maximum number of PDSCHs that can be sent in one time slot is two and 2 bits of HARQ - ACK are included in the semi - static HARQ - ACK codebook, there is an unnecessary 1 - bit overhead. The present invention proposes a method for reducing such overhead.

[0288] As an embodiment of the present invention, when the K1 granularity is a sub-slot, the UE generates a semi-static HARQ-ACK codebook by combining all the sub-slots included in a slot and using the PDSCH candidates included in the sub-slots. The semi-static HARQ-ACK codebook to be transmitted in sub-slot n can be generated as follows.

[0289] Figure 21 FIG. is a diagram illustrating a process of excluding overlapping PDSCH candidates according to an embodiment of the present invention.

[0290] Reference Figure 21 , 1) The set of K1 values that can be indicated is called K1_set. The largest K1 value is taken from K1_set. This is called K1_max. The index of the slot including the sub-slot corresponding to n - K1_max is called X. N_subslot sub-slots are configured in one slot, and X satisfies X = floor((n - K1_max) / N_subslot). The K1 values indicating the sub-slots included in slot X are taken from K1_set. That is, when an element in K1_set is called K1_value, all K1_values that satisfy X = floor((n - K1_value) / N_subslot) are taken. The set of K1 values (including K1_max) taken during the above process is called K1_max_set. The taken K1 values are excluded from K1_set.

[0291] 2) The set of PDSCH candidates that can be received in a slot is called R. If, among the sub-slots included in the sub-slots included in K1_max_set, there is a last sub-slot that overlaps with the DL slot of the PDSCH candidate included in set R, the PDSCH candidate is maintained in set R, or otherwise the PDSCH candidate is excluded from set R. Further, if the symbols of the PDSCH candidates included in set R overlap with the symbols configured for the uplink in the semi-static UL / DL configuration, the PDSCH candidates are excluded from set R.

[0292] 3) The UE performs the following steps A and B on the PDSCH candidates included in R.

[0293] A. A new 1 bit is assigned to the PDSCH candidate having the foremost last symbol. Further, if there is a PDSCH candidate in set R that overlaps with the above PDSCH candidate in at least one symbol, the PDSCH candidate is assigned the same bit position as the PDSCH candidate having the foremost last symbol. The above PDSCH candidates (including the PDSCH candidate having the foremost last symbol) are excluded from set R.

[0294] B. Repeat the above step 3-A until set R becomes an empty set.

[0295] 4) Repeat the processes of 1), 2), and 3) above until K1_set becomes an empty set.

[0296] Another problem of the present invention is to provide a specific design method for a type-1 HARQ-ACK codebook when configuring sub-slots.

[0297] According to an embodiment of the present invention, the UE includes a process of converting a K1 value (hereinafter referred to as K 1,k ) configured in sub-slot granularity into a K1 value (hereinafter referred to as K 1,k,slot ) at the slot level.

[0298] More specifically, the K1 value at the slot level can be determined as follows.

[0299]

[0300] Here, n U represents the index of the sub-slot in which the PUCCH is transmitted, and N represents the number of sub-slots in a slot. For example, when 14 symbols are configured in a slot, N is one of the values from 2 to 7, and when 12 symbols are configured in a slot, N is one of the values from 2 to 7. Here, represents the largest integer among the numbers equal to or less than x.

[0301] Figure 22 is a diagram illustrating the process of generating a type-1 HARQ-ACK according to an embodiment of the present invention.

[0302] Refer to Figure 22 , the subcarrier spacing of the downlink cell of the UE is 30 kHz, and the subcarrier spacing of the uplink cell is 15 kHz. The slots of the uplink cell are divided into seven sub-slots by combining every two consecutive symbols. That is, N = 7. In order to transmit the PUCCH in sub-slot 12 (n U = 12) of the uplink cell, the UE should generate a type-1 HARQ-ACK codebook to be included in the PUCCH. The K1 value configured in sub-slot granularity is K1 = {8, 7, 4, 3}.

[0303] Refer to Figure 22 , according to an embodiment of the present invention, the K1 value configured in sub-slot granularity can be converted into a K1 value K 1,k,slot at the slot granularity. This conversion is performed as follows.

[0304]

[0305] The UE can use the K 1,k,slotvalues to determine PDSCH candidates in each time slot. More specifically, when the pseudo-code for generating the type-1 HARQ-ACK codebook is executed in descending order of K 1,k , K 1,k values can be obtained for each K 1,k,slot . The type-1 HARQ-ACK codebook can be generated based on the obtained K 1,k,slot values.

[0306] The UE can check the validity of the PDSCH candidates to determine whether a PDSCH candidate should be included in the type-1 HARQ-ACK codebook according to the previously selected K 1,k value. If valid, the PDSCH candidate can be included in the type-1 HARQ-ACK codebook, otherwise the PDSCH candidate can be excluded from the type-1 HARQ-ACK codebook. This process can be determined based on whether the last symbol (end time) of the PDSCH candidate is included in a specific sub-time slot. If it is determined that the last symbol (end time) of the PDSCH candidate is included in a specific sub-time slot, the PDSCH candidate is determined to be valid. Otherwise, the PDSCH candidate is determined to be invalid. Here, the specific sub-time slot is sub-time slot n U -K 1,k .

[0307] Figure 23 is a diagram illustrating the process of generating type-1 HARQ-ACK according to an embodiment of the present invention.

[0308] Refer to Figure 23 , when K 1,0 = 8 is selected, the UE should determine whether the PDSCH candidate for DL time slot 1 is valid for sub-time slot n U -K 1,0 = sub-time slot 4. In Figure 23 's embodiment, it is assumed that two PDSCH candidates are configured for the UE. In Figure 23 , the first PDSCH candidate is labeled "A", and the second PDSCH candidate is labeled "B". The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in sub-time slot n U -K 1,0 = sub-time slot 4. If it is determined that the last symbol of the PDSCH candidate is included, the PDSCH candidate is determined to be valid. Otherwise, the PDSCH candidate is determined to be invalid. The last symbol (end time) of the first PDSCH candidate A is included in sub-time slot 5, rather than in sub-time slot n U -K 1,0 = sub-time slot 4. Therefore, it can be determined that the first PDSCH candidate A is invalid. The last symbol (end time) of the second PDSCH candidate B is included in sub-time slot n U -K1,0 = In sub - slot 4. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0309] Reference Figure 23 , when K 1,1 = 7 is selected, the UE shall determine whether the PDSCH candidate in DL slot 1 is valid for sub - slot n U - K 1,1 = sub - slot 5. The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in sub - slot n U - K 1,1 = sub - slot 5. If it is determined that the last symbol of the PDSCH candidate is included, the PDSCH candidate is determined to be valid. Otherwise, the PDSCH candidate is determined to be invalid. The last symbol (end time) of the first PDSCH candidate A is included in sub - slot n U - K 1,1 = sub - slot 5. Therefore, it can be determined that the first PDSCH candidate A is valid. The last symbol (end time) of the second PDSCH candidate B is included in sub - slot 4, rather than sub - slot n U - K 1,1 = sub - slot 5. Therefore, the second PDSCH candidate B can be determined to be invalid.

[0310] Reference Figure 23 , when K 1,2 = 4 is selected, the UE shall determine whether the PDSCH candidate in DL slot 2 is valid for sub - slot n U - K 1,2 = sub - slot 8. The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in sub - slot n U - K 1,2 = sub - slot 8. If it is determined that the last symbol of the PDSCH candidate is included, the PDSCH candidate is determined to be valid. Otherwise, the PDSCH candidate is determined to be invalid. The last symbol (end time) of the first PDSCH candidate A is included in sub - slot n U - K 1,2 = sub - slot 8. Therefore, it can be determined that the first PDSCH candidate A is valid. The last symbol (end time) of the second PDSCH candidate B is included in sub - slot n U - K 1,2 = sub - slot 8. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0311] Reference Figure 23 , when K 1,3 = 3 is selected, the UE shall determine whether the PDSCH candidate in DL slot 2 is valid for sub - slot n U - K 1,3= Whether sub-slot 9 is valid. The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in sub-slot n U -K 1,3 = in sub-slot 9. If it is determined that the last symbol of the PDSCH candidate is included, the PDSCH candidate is determined to be valid. Otherwise, the PDSCH candidate is determined to be invalid. The last symbol (end time) of the first PDSCH candidate A is included in sub-slot 8, rather than sub-slot n U -K 1,3 = in sub-slot 9. Therefore, it can be determined that the first PDSCH candidate A is invalid. The last symbol (end time) of the second PDSCH candidate B is included in sub-slot 8, rather than sub-slot n U -K 1,3 = in sub-slot 9. Therefore, the second PDSCH candidate B can be determined to be invalid.

[0312] More specifically, validity is established when the following conditions are met.

[0313] <Validity condition>

[0314] If subslotLengthForPUCCH-r16 is provided and sub-slot n U -K 1,K is the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived from row r in the time slot .

[0315] Here, n U,slot is the index of the time slot corresponding to sub-slot n U and can be obtained as

[0316] When the following conditions are met, validity does not hold.

[0317] <Invalid condition>

[0318] If subslotLengthForPUCCH-r16 is provided and sub-slot n U -K 1,K is not the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived from row r in the time slot .

[0319] With this correction, the existing version 15 / 16 pseudo-code for generating type-1 HARQ-ACK can be minimally corrected and applied to sub-slot configurations. More specifically, the first pseudo-code is as follows. For reference, here, all variables can refer to the 3GPP standard document TS38.213.

[0320] <First pseudo-code>

[0321] [Table 5]

[0322]

[0323]

[0324]

[0325]

[0326]

[0327]

[0328] The above pseudocode is based on a K 1,k value and can be summarized into the following steps.

[0329] As the first step, the UE converts the above K 1,k value represented in sub-slot granularity into K 1,k,slot represented in slot granularity. The above steps are given in the above pseudocode as

[0330] As the second step, the UE can check the validity based on the last symbol of each PDSCH candidate belonging to the SLIV table. Here, if the last symbol of the PDSCH candidate is included in the corresponding sub-slot n U -K 1,k then it can be determined that the PDSCH candidate is valid. If it is determined that the PDSCH candidate is invalid, the PDSCH candidate is excluded during the generation of the type-1 HARQ-ACK codebook. The above steps are given in the above pseudocode as follows.

[0331] if subslotLengthForPUCCH-r16 is provided and sub-slot n U -K 1,K is not the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived from row r in the slot then R = R\r;

[0332] R = R\r;

[0333] According to the above two steps, valid PDSCH candidates can be included in the set R. After that, the valid PDSCH candidates in the set R can be used to generate the type-1 HARQ-ACK codebook.

[0334] When generating the type-1 HARQ-ACK codebook in this way, the following problems may occur.

[0335] A UE can have various capabilities. When the UE has a specific capability, the UE can notify the base station of this capability. This is called capability reporting. The base station can determine the transmission and reception methods to be used for the UE based on the capability report obtained from the UE.

[0336] If the UE does not have a specific capability, the UE can receive one PDSCH in one DL time slot. In other words, the UE does not expect to be indicated or configured to receive two or more PDSCHs for one DL time slot. Therefore, for one DL time slot, the type-1 HARQ-ACK codebook generated by the UE only includes the HARQ-ACK of one PDSCH received in one DL time slot.

[0337] The UE can have the capability to receive two or more PDSCHs in one DL time slot. In this case, the type-1 HARQ-ACK codebook generated by the UE includes the HARQ-ACK of at least one PDSCH received in one DL time slot for one DL time slot.

[0338] As described above, the type-1 HARQ-ACK codebook generation method can vary according to the capabilities. This is described in the following pseudocode.

[0339]

[0340] Assume that two or more values are provided to the UE as K 1,k values. When transmitting the PUCCH including the type-1 HARQ-ACK codebook in sub-slot n U , the type-1 HARQ-ACK codebook is generated as follows. One K 1,k value (referred to as K 1,k1 here) can be used to obtain sub-slot n U - K 1,k1 , and the DL time slot corresponding to this sub-slot n U - K 1,k1 can be obtained. This DL time slot is called the first DL time slot. Another K 1,k value (referred to as K 1,k2 here) can be used to obtain sub-slot K 1,k2 , and the DL time slot corresponding to this sub-slot n U - K 1,k2 can be obtained. This DL time slot is called the second DL. The first DL time slot and the second DL time slot can be the same or different from each other. Here, assume that the first DL time slot and the second DL time slot are the same. For reference, here, the DL time slot corresponding to sub-slot n U - K 1,k1 can be the same as the DL time slot corresponding to sub-slot n U - K 1,k1Overlapping DL time slots. Here, the DL time slot corresponding to sub-slot n U -K 1,k2 can be a DL time slot overlapping with sub-slot n U -K 1,k2 and is an overlapping DL time slot.

[0341] Assume that the UE does not have a specific capability. According to the first piece of pseudo-code, if there is at least one valid PDSCH candidate in the first DL time slot corresponding to a K 1,k value (referred to as K 1,k1 here), the UE includes a HARQ-ACK for the PDSCH candidate in the first DL time slot in the type-1 HARQ-ACK codebook. As described above, since the UE can receive at most one PDSCH even if there are multiple PDSCH candidates in the first DL time slot, one HARQ-ACK is included in the type-1 HARQ-ACK codebook. If there is at least one valid PDSCH candidate in the second DL time slot corresponding to another K 1,k value (referred to as K 1,k2 here), a HARQ-ACK for the PDSCH candidate in the second DL time slot is included in the type-1 HARQ-ACK codebook. The problem is that the first DL time slot and the second DL time slot can be the same DL time slot as in the above example. In this case, according to the first piece of pseudo-code, the UE includes two HARQ-ACKs in one DL time slot (the first DL time slot or the second DL time slot) in the type-1 HARQ-ACK codebook. As described above, assuming that the UE can receive at most one PDSCH in one DL time slot, the UE can only include one HARQ-ACK; however, since more HARQ-ACKs are included, that is, two HARQ-ACKs, there will be a problem that the size of the type-1 HARQ-ACK codebook increases.

[0342] Reference Figure 23 , the DL time slot corresponding to K 1,0 is DL time slot 1. In DL time slot 1, the second PDSCH candidate B is a valid PDSCH candidate. Therefore, the type-1 HARQ-ACK codebook includes a HARQ-ACK for the above DL time slot. Next, the DL time slot corresponding to K 1,1 is DL time slot 1. In DL time slot 1, the first PDSCH candidate A is a valid PDSCH candidate. Therefore, the type-1 HARQ-ACK codebook includes a HARQ-ACK for the above DL time slot. Therefore, the type-1 HARQ-ACK codebook includes at least two HARQ-ACKs for DL time slot 1.

[0343] The present invention proposes a method to solve this problem.

[0344] According to an embodiment of the present invention, if there is at least one valid PDSCH candidate in the DL time slot corresponding to a K 1,k value, the UE includes a HARQ-ACK for the PDSCH candidate of the DL time slot in the type-1 HARQ-ACK codebook. Here, the UE may check whether the HARQ-ACK for the DL time slot is included in the type-1 HARQ-ACK codebook to determine whether to include the HARQ-ACK. That is, if the HARQ-ACK for the DL time slot has already been included in the type-1 HARQ-ACK codebook, the UE does not include the HARQ-ACK in the type-1 HARQ-ACK codebook because an additional HARQ-ACK for the DL time slot is not required. On the contrary, if the HARQ-ACK for the DL time slot is not included in the type-1 HARQ-ACK codebook, the UE includes the HARQ-ACK in the type-1 HARQ-ACK codebook because the HARQ-ACK for the DL time slot is necessary.

[0345] In this way, the UE can include only one HARQ-ACK in the type-1 HARQ-ACK codebook for one DL time slot. When the UE receives the PDSCH in the DL time slot, the HARQ-ACK of the PDSCH can be sent at the bit position corresponding to the received DL time slot in the type-1 HARQ-ACK codebook.

[0346] Reference Figure 23 , the DL time slot corresponding to K 1,0 is DL time slot 1. In DL time slot 1, the second PDSCH candidate B is a valid PDSCH candidate. Therefore, the type-1 HARQ-ACK codebook includes the HARQ-ACK for DL time slot 1. Next, the DL time slot corresponding to K 1,1 is DL time slot 1. In DL time slot 1, the first PDSCH candidate A is a valid PDSCH candidate. Here, although there is a valid PDSCH candidate, the HARQ-ACK for the corresponding DL time slot has already been included and thus is not included additionally. If the UE receives the first PDSCH candidate A in DL time slot 1, the UE can send the HARQ-ACK of the first PDSCH candidate A at the position of the HARQ-ACK included for DL time slot 1. In addition, if the UE receives the second PDSCH candidate B in DL time slot 1, the UE can send the HARQ-ACK of the first PDSCH candidate A at the position of the HARQ-ACK included for DL time slot 1.

[0347] According to the above first piece of pseudo-code, a K1 value is taken from a set of K1 values, and based on this K1 value, valid PDSCH candidates are determined, and the HARQ-ACK bit positions among the valid PDSCH candidates are determined. Here, the granularity of the K1 value is a sub-slot. That is, within a sub-slot, valid PDSCH candidates are determined, and the HARQ-ACK bit positions are determined among the valid PDSCH candidates. However, since the PDSCH is scheduled in units of slots rather than sub-slots, it is inefficient to generate a type-1 HARQ-ACK codebook for each sub-slot. To solve this problem, a type-1 HARQ-ACK codebook needs to be generated for each slot.

[0348] For example, referring to Figure 23 , for K 1,0 = 8, the UE obtains the corresponding DL slot 1 and checks the validity of the two PDSCH candidates A and B in DL slot 1. Thereafter, for K 1,1 = 7, the UE obtains the corresponding DL slot 1 and checks the validity of the two PDSCH candidates A and B in DL slot 1. That is, the operations performed on K 10 are redundantly performed on K 11 .

[0349] To avoid such redundant operations, it is desirable for the UE to determine the validity of PDSCH candidates by converting K 1,k to K 1,k,slot and obtaining the DL slot according to the K 1,k,slot value instead of by obtaining the DL slot for each sub-slot corresponding to K 1,k .

[0350] According to an embodiment of the present invention, the UE includes a process of converting a K1 value configured with sub-slot granularity (hereinafter referred to as K 1,k ) to a slot-level K1 value (hereinafter referred to as K 1,k,slot ).

[0351] More specifically, the slot-level K1 value can be determined as follows.

[0352]

[0353] The set of K 1,k,slot values is referred to as K 1,slot . For reference, two or more K 1,k may have the same K 1,k,slot value. In other words, multiple K 1,k,slot values can correspond to one K 1,slot value in the K 1,k,slot set.

[0354] Return to referenceFigure 22 , K can be obtained as follows 1,k,slot .

[0355]

[0356] Therefore, K 1,slot is determined such that K 1,slot = {1, 0}.

[0357] The UE can generate a Type-1 HARQ-ACK codebook according to the descending order of the K 1,slot values in the K 1,k,slot set. That is to say, the largest K 1,slot value can be taken from the K 1,k,slot set to determine the valid PDSCH candidates for the DL time slot corresponding to this K 1,k,slot . Next, the second largest K 1,slot value can be taken from the K 1,k,slot set to determine the valid PDSCH candidates for the DL time slot corresponding to K 1,k,slot . This operation can be repeated until the valid PDSCH candidates for the DL time slot corresponding to K 1,slot are determined by taking the smallest K 1,k,slot value from the K 1,k,slot set.

[0358] The UE can check the validity of the PDSCH candidates to determine whether the PDSCH candidates should be included in the Type-1 HARQ-ACK codebook according to the previously selected K 1,k,slot values. If valid, the PDSCH candidates can be included, otherwise the PDSCH candidates can be excluded. This process can be determined based on whether the last symbol (end time) of the PDSCH candidate is included in a specific sub-time slot. Here, the specific time slot is described as follows. When the K 1,k,slot values corresponding to the K 1,k value are defined as K 1,k1 , K 1,k2 , …, the sub-time slot n U -K 1,k1 , the sub-time slot n U -K 1,k2 , ….

[0359] Reference Figure 23 , when K 1,0,slot = 1 is selected, the UE should determine whether the PDSCH candidates for the DL time slot 1 are valid for the sub-time slot n U -K 1,0 = sub-time slot 4 and the sub-time slot n U -K 1,1 = sub-time slot 5. As a reference, K 1,0,slot = 1 corresponds to K 1,0= 8 and K 1,1 = 7. In Figure 23 's embodiment, it is assumed that two PDSCH candidates are configured for the UE. In Figure 23 , the first PDSCH candidate is labeled "A", and the second PDSCH candidate is labeled "B". The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in sub-slot n U -K 1,0 = sub-slot 4 or sub-slot n U -K 1,1 = sub-slot 5. If it is determined that the last symbol of the PDSCH candidate is included, it is determined that the PDSCH candidate is valid. Otherwise, the PDSCH candidate is determined to be invalid. The last symbol (end time) of the first PDSCH candidate A is included in sub-slot n U -K 1,1 = sub-slot 5. Therefore, it can be determined that the first PDSCH candidate A is valid. The last symbol (end time) of the second PDSCH candidate B is included in sub-slot n U -K 1,0 = sub-slot 4. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0360] Refer to Figure 23 , when K 1,1,slot = 0 is selected, the UE should determine whether the PDSCH candidate of DL slot 2 for sub-slot n U -K 1,2 = sub-slot 8 and sub-slot n U -K 1,3 = sub-slot 9 is valid. As a reference, K 1,1,slot = 0 corresponds to K 1,2 = 4 and K 1,3 = 3. The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in sub-slot n U -K 1,2 = sub-slot 8 or sub-slot n U -K 1,3 = sub-slot 9. If it is determined that the last symbol of the PDSCH candidate is included, it is determined that the PDSCH candidate is valid. Otherwise, the PDSCH candidate is determined to be invalid. The last symbol (end time) of the first PDSCH candidate A is included in sub-slot n U -K 1,2 = sub-slot 8. Therefore, it can be determined that the first PDSCH candidate A is valid. The last symbol (end time) of the second PDSCH candidate B is included in sub-slot n U -K 1,2 = sub-slot 8. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0361] More specifically, validity is established when the following conditions are met.

[0362] <Validity condition>

[0363] If subslotLengthForPUCCH-r16 is provided and at least one of the sub-slots n U -K 1,K is the last UL sub-slot overlapping with the DL sub-slot of the PDSCH time resource derived from row r in the slot where K 1,k is associated with K 1,K,slot

[0364] Here, n U,slot is the index of the slot corresponding to sub-slot n U and can be obtained as

[0365] Validity does not hold when the following conditions are met.

[0366] <Invalid condition>

[0367] If subslotLengthForPUCCH-r16 is provided and all sub-slots n U -K 1,K are not the last UL sub-slot overlapping with the DL sub-slot of the PDSCH time resource derived from row r in the slot where K 1,k is associated with K 1,K,slot

[0368] If the last symbol of the PDSCH candidate is not included in all sub-slots, this is invalid.

[0369] With this correction, the existing version 15 / 16 pseudo-code for generating type-1 HARQ-ACK can be minimally corrected and applied to the sub-slot configuration. More specific pseudo-code is as follows. For reference, here, all variables can refer to the 3GPP standard document TS38.213.

[0370] <Second pseudo-code>

[0371] [Table 6]

[0372]

[0373]

[0374]

[0375] ​​

[0376]

[0377]

[0378] In an NR wireless communication system, a UE can use a semi-static HARQ-ACK codebook to send HARQ-ACK information. When using a semi-static HARQ-ACK codebook, the base station can configure the length of the HARQ-ACK codebook using an RRC signal and indicate which PDSCH each bit of the HARQ-ACK codebook indicates an ACK / NACK for. Therefore, the base station does not have to signal the information required to send the HARQ-ACK codebook every time it is needed. The set of PDSCHs whose ACK / NACK is indicated by the semi-static HARQ-ACK codebook is referred to as the PDSCH candidate set. Below, a method for a UE to determine the PDSCH candidate set will be described with reference to Figure 24 Describe the method for a UE to determine the PDSCH candidate set.

[0379] The UE determines the PDSCH candidate set based on information signaled from the base station. Here, the information signaled from the base station can include K1. K1 indicates the difference between the last time slot in which the PDSCH is received or scheduled and the time slot in which the PUCCH is transmitted. The fallback DCI (DCI format 1_0) can indicate the K1 value as one of 1, 2, 3, 4, 5, 6, 7, and 8. The non-fallback DCI (DCI formats 1_1 to 1_2) can indicate one of up to eight values configured by an RRC signal as the K1 value. In addition, the information signaled from the base station can include the combination of the length of the PDSCH within a time slot and the starting symbol of the PDSCH and K0. Here, K0 indicates the difference between the time slot in which the PDCCH is received and the time slot in which the PDSCH scheduled by the corresponding PDCCH is received. In addition, the combination of the starting symbol of the PDSCH within a time slot and the length of the PDSCH can be encoded in the form of a starting and length indicator value (SLIV) value. The base station can signal up to 16 K0 values and the combination of the starting symbol and length of the PDSCH. The UE can obtain one of 16 combinations from the DCI that schedules the PDSCH. The UE can obtain information about the time domain in which the PDSCH is received from the K0 value indicated by the DCI and the starting symbol and length of the PDSCH within the time slot.

[0380] In addition, the information signaled from the base station may include semi-static DL / UL configuration. The semi-static DL / UL configuration represents symbol configuration information of time slots configured by cell-specific RRC signals or UE-specific RRC signals. Specifically, this configuration may indicate whether each symbol included in a time slot is a DL symbol, a UL symbol, or a flexible symbol. The UE may determine the PDSCH candidate set based on whether any one of the symbols allocated with PDSCH corresponds to a UL symbol. This is because a PDSCH cannot be received on a symbol corresponding to a UL symbol. In a specific embodiment, where any one of the symbols allocated with PDSCH corresponds to a UL symbol, the UE may not include the corresponding PDSCH in the PDSCH candidate set. If all the symbols to which the PDSCH is allocated do not correspond to UL symbols, the UE may include the corresponding PDSCH in the PDSCH candidate set.

[0381] In addition, the information signaled from the base station may include information on the configuration of CORESET and search space. The information on the configuration of CORESET and search space may indicate at which position in which time slot the PDCCH can be received.

[0382] In addition, the information signaled from the base station may include a PDSCH repetition value. When receiving the PDSCH for each time slot, the base station may receive the same PDSCH the number of times indicated by the PDSCH repetition value. Here, the UE may start receiving the PDSCH at the same symbol position in each time slot. In addition, the UE may receive the PDSCH using the same length in each time slot. The base station may set the PDSCH repetition value to any one of 1, 2, 4, and 8 using an RRC signal. When the PDSCH repetition value is greater than 1, it can be said that time slot aggregation is used. When the reception of the PDSCH is configured to be repeated in multiple time slots, the UE may determine whether the condition for including the corresponding PDSCH in the PDSCH candidate set is met based on whether the PDSCH can be received in all the time slots in which it is received. Specifically, when the UE determines that PDSCH reception is not possible in all the time slots in which the PDSCH is indicated to be repeatedly received, the UE may not include the corresponding PDSCH in the PDSCH candidate set. In another embodiment, when the PDSCH can be received in any one of the time slots in which the reception of the PDSCH is indicated, the UE may include the corresponding PDSCH in the PDSCH candidate set.

[0383] Based on whether the PDSCH candidate indicated by the SLIV is valid for each of the multiple K1 values and K0, the UE includes in the PDSCH candidate set the combination of each of the K1 value, K0, and the PDSCH candidate indicated by the SLIV. It can be determined whether the PDSCH candidate indicated by the SLIV is valid for each of the multiple K1 values and K0. When the combination of the corresponding K1 value, K0, and the PDSCH candidate indicated by the SLIV is valid, the UE may include the combination of the corresponding K1 value, K0, and the PDSCH candidate indicated by the SLIV in the PDSCH candidate set. For convenience, the time slot in which the PUCCH is transmitted is referred to as the nth time slot. When any one of the symbols for which the SLIV indicates the allocation of the PDSCH corresponds to the UL symbol in the corresponding time slot among all of the n-K1th time slot, n-K1-1th time slot, ..., n-K1-(N rep -1)th time slot, the UE may determine that the PDSCH candidate indicated by the corresponding SLIV is invalid for the corresponding K1 value and K0. Here, N rep represents the number of time slots in which the PDSCH is repeatedly received. As described above, N rep can be set by the RRC signal. In addition, when PDSCH repetition is not used, N rep can be such that N rep = 1. When any one of the symbols for which the SLIV indicates the allocation of the PDSCH corresponds to the UL symbol in the n-K1th time slot, the UE may determine that the PDSCH candidate indicated by the corresponding SLIV is invalid for the corresponding K1 value and K0. Further, when there is no search space in the n-K1-(N rep -1)-K0 time slot, the UE may determine that the PDSCH candidate indicated by the corresponding SLIV is invalid for the corresponding K1 value and K0. As described above, when PDSCH repetition is not used, N rep can be such that N rep = 1. Specifically, when all of the symbols for which the SLIV indicates the allocation of the PDSCH do not correspond to the UL symbol in any one of the n-K1 time slot, n-K1-1 time slot, ..., and n-K1-(N rep -1) time slot, and there is a search space in the n-K1-(N rep -1)-K0 time slot, the UE may determine that the PDSCH candidate indicated by the SLIV is valid for the corresponding K1 value and K0. When the UE determines that the PDSCH candidate indicated by the SLIV value is invalid, the UE may not include the combination of the corresponding K1 value, K0, and the PDSCH candidate indicated by the SLIV in the PDSCH candidate set.

[0384] Figure 24It is illustrated to determine whether the PDSCH candidate indicated by the SLIV signaled to the UE is included in the PDSCH candidate set according to K1 and K0 according to an embodiment of the present invention.

[0385] In Figure 24 the embodiment of, any one of the symbols for which the SLIV indicates the allocation of the PDSCH corresponds to the UL symbol in the corresponding time slot among all of the n-K1 time slot, the n-K1-1 time slot,..., and the n-K1-(N rep -1) time slots. Therefore, the UE determines that the PDSCH candidate indicated by the SLIV is invalid for the corresponding K1 value and K0. The UE does not include in the PDSCH candidate set the combination of the corresponding K1 value, K0, and the PDSCH candidate indicated by the SLIV.

[0386] Based on whether the PDSCH candidate of the combination of K1 value, K0, and SLIV included in the PDSCH candidate set overlaps with the PDSCH candidate of another combination of K1 value, K0, and SLIV included in the PDSCH candidate set in at least one symbol in at least one time slot, the UE combines these two combinations into one combination. The UE may determine whether the PDSCH candidate of the combination of K1 value, K0, and SLIV included in the PDSCH candidate set overlaps with the PDSCH candidate of another combination of K1 value, K0, and SLIV included in the PDSCH candidate set in at least one symbol in at least one time slot. When the PDSCH candidate of the combination of K1 value, K0, and SLIV included in the PDSCH candidate set overlaps with the PDSCH candidate of another combination of K1 value, K0, and SLIV in at least one symbol in at least one time slot, the UE may combine the two combinations into one combination. In a specific embodiment, when the PDSCH candidate set includes N combinations, the UE may determine whether the PDSCH candidate of the nth combination overlaps with the PDSCH candidates of each of the combinations up to m=n+1,..., N. Here, the UE may perform the operations related to the overlap determination sequentially from n=0 to n=N-1.

[0387] Based on the position of the last symbol of the PDSCH included in the PDSCH candidate set, the UE can determine the position of the corresponding PDSCH in the semi-static HARQ-ACK codebook for HARQ-ACK information. Specifically, according to the position of the last symbol of the PDSCH included in the PDSCH candidate set, the UE can determine the position of the bit in the HARQ-ACK codebook that indicates the ACK / NACK of the corresponding PDSCH. In detail, the position of the HARQ-ACK information of the PDSCH with the last symbol in the front can also be in the front. For example, when the last symbol of the first PDSCH is before the last symbol of the second PDSCH, the bit in the HARQ-ACK codebook that indicates the ACK / NACK of the first PDSCH can be before the bit that indicates the ACK / NACK of the second PDSCH.

[0388] The UE can send different UCI types by multiplexing different UCI types (HARQ-ACK, SR, or CSI (part 1 or part 2)) in the PUCCH. The UE can determine the maximum number of bits that the PUCCH can send. This can be configured in the base station, or can be determined using at least one piece of information among the maximum code rate and the number of symbols, the number of PRBs, and the number of DM-RS symbols set for the PUCCH. If the number of bits of the above UCI is greater than the maximum number of bits that the PUCCH can send, the UE cannot send all the DCIs and thus may not send some UCI types.

[0389] For example, CSI part 2 can be excluded. If the number of bits of the UCI is still greater than the maximum number of bits even when CSI part 2 is excluded, CSI part 1 can be excluded. If the number of bits of the UCI is still greater than the maximum number of bits even when CSI part 1 is excluded, SR can be excluded. If the number of bits of the UCI is still greater than the maximum number of bits even when SR is excluded, a process (bundling) can be performed to discard or combine a part or all of the HARQ-ACK. Thereafter, the present invention relates to a method for reducing the number of bits of the HARQ-ACK.

[0390] As described above, the size (i.e., the number of bits) of the semi-static HARQ-ACK codebook is determined according to the signaling from the base station. Since this size does not change according to the number of PDSCHs actually received by the UE, the size of the semi-static HARQ-ACK codebook sent by the UE is the same even if the UE fails to receive a certain PDSCH.

[0391] In certain cases, the UE may not be able to send a given semi-static HARQ-ACK codebook. At this time, the UE may only send the HARQ-ACK bits of some PDSCHs in the semi-static HARQ-ACK codebook, or may combine and send the information of the HARQ-ACK bits of some or all PDSCHs in the semi-static HARQ-ACK codebook. Here, only sending the HARQ-ACK bits of some PDSCHs is called discarding, and combining and sending the information of some or all bits is called bundling.

[0392] Discarding means only sending the HARQ-ACK bits of some PDSCHs in the semi-static HARQ-ACK codebook without sending the HARQ-ACK bits of other PDSCHs. Through this process, the UE can reduce the size (i.e., the bit size) of the semi-static HARQ-ACK codebook. For example, assume the size of the semi-static HARQ-ACK codebook is A bits. If the bit size that the UE can send is B bits (B < A), then the UE should only select and send B bits from the semi-static HARQ-ACK codebook. For reference, the UE can select less than B bits. In addition, although the description has been provided in terms of bits, this can be replaced by the number of PDSCHs.

[0393] The problem to be solved by the present invention relates to a method for determining the PDSCH for which the HARQ-ACK bits are to be sent when performing discarding.

[0394] Bundling is a scheme for combining and sending the information of the HARQ-ACK bits of some or all PDSCHs in the semi-static HARQ-ACK codebook, and the combination scheme can be as follows. If all the HARQ-ACK bits to be combined are ACK, the combined HARQ-ACK bit is ACK. Otherwise, the combined HARQ-ACK bit is NACK. In another expression, ACK is called the binary number 1 (or "true"), and NACK is called 0 (or "false"). The combined HARQ-ACK bit can be determined as the binary product of the HARQ-ACK bits to be combined.

[0395] The problem to be solved by the present invention relates to a method for determining the PDSCH for which the HARQ-ACK information is to be combined when performing bundling.

[0396] The first to fourth embodiments are embodiments applicable to the case where the UE receives PDSCH in one cell. The first embodiment is applicable to the case of receiving PDSCH in multiple cells (i.e., the case of carrier aggregation (CA)).

[0397] As a first embodiment, when the number of HARQ-ACK bits included in the semi-static HARQ-ACK codebook (here A bits) is greater than the number of bits that the UE can transmit (here B bits), the UE may not transmit the entire semi-static HARQ-ACK codebook. That is, even when the UE is short of bits by up to 1 bit compared to the number of bits that can be transmitted, the UE may not transmit the semi-static HARQ-ACK codebook.

[0398] As a second embodiment, the UE may transmit some bits of the semi-static HARQ-ACK codebook and may not transmit other bits. Here, the selection of some bits to be transmitted may be based on the position of the bits in the semi-static HARQ-ACK codebook. Preferably, some bits to be transmitted may be the bits arranged in the front positions in the semi-static HARQ-ACK codebook.

[0399] For example, assume that the size of the semi-static HARQ-ACK codebook is A bits. If the size of the bits that the UE can transmit is B bits (B < A), the UE may select and transmit only the first B bits from the semi-static HARQ-ACK codebook.

[0400] Figure 25 FIG. is a diagram illustrating a method for reducing the HARQ-ACK size according to an embodiment of the present invention.

[0401] Reference Figure 25 , K1 has two values (K1(1) and K1(2)), and the number of cells is one. According to the semi-static HARQ-ACK codebook generation scheme, four HARQ-ACK bits for the PDSCH are generated according to each K1 value. That is, [b0 b1 b2 b3] is generated as the HARQ-ACK bits for 4 PDSCHs according to the K1(1) value, and [b4 b5 b6 b7] is generated as the HARQ-ACK bits for 4 PDSCHs according to the K1(2) value. In addition, the UE transmits [b0 b1 b2 b3 b4 b5 b6 b7] using the semi-static HARQ-ACK codebook.

[0402] In Figure 25 's embodiment, if the UE should only select and transmit B = 5 bits, the UE should select 5 bits out of A = 8 bits. According to the second embodiment, the UE may select the first 5 bits from A = 8 bits. This may be [b0 b1 b2 b3 b4].

[0403] Although the method of selecting some bits has been described with respect to the second embodiment, this can be partly replaced by PDSCH. More specifically, assume that the semi-static HARQ-ACK codebook includes HARQ-ACK bits for A number of PDSCHs. The number of HARQ-ACK bits corresponding to the respective PDSCHs may be the same or different. Further, the number of HARQ-ACK bits corresponding to the respective PDSCHs may be 1 bit or multiple bits. The UE may select the HARQ-ACK bits of the PDSCHs arranged in the front positions in the semi-static HARQ-ACK codebook as the bits to be transmitted. Here, when the HARQ-ACK bits of a certain PDSCH are partly but not entirely included in the semi-static HARQ-ACK codebook, all of the HARQ-ACK bits of that PDSCH are excluded.

[0404] For example. Assume that the size of the semi-static HARQ-ACK codebook is A bits. If the size of the bits that the UE can transmit is B bits (B < A), then the UE selects the first B bits from the semi-static HARQ-ACK codebook, where the UE checks whether the HARQ-ACK bits of the last PDSCH among the PDSCHs corresponding to the B HARQ-ACKs are included in the above B bits. If these HARQ-ACK bits are included, the semi-static HARQ-ACK codebook configured by the above B bits can be transmitted. If these HARQ-ACK bits are not included, the HARQ-ACK bits of the last PDSCH can be excluded from the semi-static HARQ-ACK codebook configured by the above B bits.

[0405] As a third embodiment, the UE may determine the bits to be transmitted in the semi-static HARQ-ACK codebook based on the index of the time slot. Here, the index of the time slot may be determined according to the K1 value. The UE may transmit the HARQ-ACK bits corresponding to the time slot with the lower index (earlier in time) among the time slots, and may not transmit the HARQ-ACK bits corresponding to the time slot with the higher index (later in time) among the time slots. As a reference, a larger K1 value indicates a time slot earlier in time.

[0406] For example, assume that the size of the semi-static HARQ-ACK codebook is A bits. If the size of the bits that the UE can transmit is B bits (B < A), then the UE sequentially calculates the HARQ-ACK bit lengths starting from the earlier time slots in the semi-static HARQ-ACK codebook, and if the calculated HARQ-ACK bit length is less than B, the HARQ-ACK bit length is calculated by including the next time slot. If the HARQ-ACK bit length including the next time slot is greater than B, the HARQ-ACK bits can be determined by including only the HARQ-ACK bits of the earlier time slots and not including the HARQ-ACK bits of the next time slot.

[0407] Figure 26 It is a diagram illustrating a method for reducing the size of HARQ-ACK according to an embodiment of the present invention.

[0408] Reference Figure 26 , if the UE is supposed to select and transmit only B = 5 bits, the UE calculates the HARQ-ACK bits for the earliest time slot (here, time slot n-K1(1)). Here, the calculated HARQ-ACK bits are [b0 b1 b2 b3], which are 4 bits. Since this is less than B = 5 bits, the HARQ-ACK bits for the next time slot can be calculated. By including the HARQ-ACK bits calculated for the next time slot (here, time slot n-K1(2)), it is [b0 b1 b2 b3 b4 b5 b6 b7], which are 8 bits. Therefore, the UE can determine [b0 b1 b2 b3] (which are the HARQ-ACK bits calculated in the previous time slot (here, time slot n-K1(1))) as the HARQ-ACK bits to be transmitted.

[0409] In the second and third embodiments, the UE only transmits the HARQ-ACK for the PDSCH of a specific time slot (here, time slot n-K1(1)), and cannot transmit the HARQ-ACK for the PDSCH of another time slot (here, time slot n-K1(2)). Therefore, even if the base station schedules the PDSCH for different time slots, it may not be possible to transmit the HARQ-ACK for some time slots. Embodiments for solving this problem will be disclosed.

[0410] As a fourth embodiment, the UE can allocate the bits that can be transmitted to each time slot, so that the UE can select the bits to be transmitted. More specifically, the bits that can be transmitted are allocated to the time slots according to the K1 value in the semi-static HARQ-ACK codebook, so as to determine the bits to be transmitted.

[0411] For example, when the number of bits that the UE can transmit is A bits and the K1 value is K, the number of bits to be transmitted in each time slot can be determined based on A and the K1 value. For example, the quantity can be determined based on A / K. When A / K is not an integer, at least one of ceil(A / K), round(A / K), or floor(A / K) can be determined as the number of bits to be transmitted in each time slot. When the number of bits that can be transmitted in each time slot is determined, the UE can determine the bits to be transmitted and the bits not to be transmitted in each time slot. Preferably, the bits in the front of the time slot can be determined as the bits to be transmitted, and the bits in the back can be determined as the bits not to be transmitted.

[0412] Figure 27 It is a diagram illustrating a method for reducing the size of HARQ-ACK according to an embodiment of the present invention.

[0413] Reference Figure 27 Figure 27 If the UE is supposed to select and transmit only B = 4 bits, the UE can transmit only two bits in each time slot (time slot n-K1(1) and time slot n-K1(2)). Therefore, only two leading bits can be selected for transmission in each time slot [b0 b1 b4 b5].

[0414] The above embodiments are described with respect to one cell. However, in the above embodiments, the time slots can be replaced by cells, and thus the above method can be understood as a method of selecting and transmitting some HARQ-ACK bits of different cells.

[0415] When the UE is configured to receive PDSCH from two or more cells (i.e., in the case of carrier aggregation (CA)), the following can be considered.

[0416] First, in the case of CA, the UE can be configured with different reception methods for each cell. Here, the reception methods can include a TB-based PDSCH reception method, a CBG-based PDSCH reception method, a reception method with 1 TB per PDSCH, and a reception method with 2 TB per PDSCH. If the number of bits of the semi-static HARQ-ACK codebook is greater than the number of bits that the UE can transmit, considering that different cells have different reception methods, the following method needs to be adopted.

[0417] As a first method, when a CBG-based PDSCH reception is configured in a cell, the UE generates a semi-static HARQ-ACK codebook by assuming the CBG-based PDSCH reception as a TB-based PDSCH reception in the cell. Here, the ACK / NACK of the TB-based PDSCH reception is determined according to whether the TB-CRC is successful. That is, 1 bit of HARQ-ACK is generated per TB. Alternatively, 1 bit per TB generated by the TB-based PDSCH reception can be obtained by bundling the N_CBG bits of ACK / NACK generated by the CBG-based PDSCH reception. When the size of the semi-static HARQ-ACK codebook generated by assuming the TB-based PDSCH reception is equal to or less than the number of bits that can be transmitted (here B bits), the UE can transmit the semi-static HARQ-ACK codebook. When the size of the semi-static HARQ-ACK codebook generated by assuming the TB-based PDSCH reception is greater than the number of bits that can be transmitted (here B bits), the UE cannot transmit the semi-static HARQ-ACK codebook. In this case, additional HARQ-ACK bits need to be discarded or bundled. This will be described later.

[0418] Figure 28FIG. is a diagram illustrating a method for reducing the HARQ-ACK size in the case of carrier aggregation according to an embodiment of the present invention.

[0419] Referring Figure 28 to (a) and (b) of 21 , M 22 , M 23 , and M 34 ), the UE is configured to receive PDSCH from three cells CC#0, CC#1, and CC#2, and four K1 values K1(1), K1(2), K1(3), and K1(4) are set. One cell CC#0 is configured for TB-based PDSCH reception and receives 1 TB per PDSCH reception, another cell CC#1 is configured for TB-based PDSCH reception and receives 2 TB per PDSCH reception, and another cell CC#2 is configured for CBG-based PDSCH reception and receives 1 TB per PDSCH reception. According to the first method, the UE generates a semi-static HARQ-ACK codebook by assuming TB-based HARQ-ACK to reduce the number of HARQ-ACK bits (M 21 , N 22 , N 23 , and N 24 ) generated according to the CBG-based PDSCH reception of CC#2. The resulting number of HARQ-ACK bits (N 21 , N 22 , N 23 , and N 24 ) is 1 bit per PDSCH.

[0420] As a second method, the UE may generate a semi-static HARQ-ACK codebook by assuming TB-based PDSCH reception for the cells in which CBG-based PDSCH reception is configured one by one in sequence, and may determine whether transmission is possible. The UE generates a semi-static HARQ-ACK codebook by assuming TB-based PDSCH reception for one of the cells in which CBG-based PDSCH reception is configured, and if the semi-static HARQ-ACK codebook is equal to or less than the number of bits that the UE can send, the semi-static HARQ-ACK codebook is sent. If the semi-static HARQ-ACK codebook is greater than the number of bits that the UE can send, the UE generates a semi-static HARQ-ACK codebook by assuming TB-based PDSCH reception for another cell in which CBG-based PDSCH reception is configured, and if the semi-static HARQ-ACK codebook is equal to or less than the number of bits that the UE can send, the semi-static HARQ-ACK codebook is sent. If after performing this process for all cells in which CBG-based PDSCH reception is configured, the size of the semi-static HARQ-ACK codebook is still greater than the number of bits that the UE can send, the semi-static HARQ-ACK codebook cannot be sent. In this case, additional HARQ-ACK bits need to be discarded or bundled. This will be described later.

[0421] As a third method, when two TBs are configured for each PDSCH reception in a cell, the UE generates one bit by bundling the HARQ-ACK bits of the two TBs in the cell (this bundling is called spatial bundling), and generates a semi-static HARQ-ACK codebook based on the above bit. If the size of the semi-static HARQ-ACK codebook generated based on the spatial bundling bit is equal to or less than the number of bits that can be transmitted (here B bits), the UE can transmit the semi-static HARQ-ACK codebook. If the size of the semi-static HARQ-ACK codebook generated based on the spatial bundling bit is greater than the number of bits that can be transmitted (here B bits), the UE cannot transmit the semi-static HARQ-ACK codebook. In this case, additional HARQ-ACK bits need to be discarded or bundled. This will be described later.

[0422] Refer to Figure 28 (a) and (c) of, according to the third method, the UE can spatially bundle the ACK / NACKs of two TBs of one PDSCH to reduce the number of HARQ-ACK bits (L 21 、L 22 、L 23 and L 34 ) generated according to the configuration of two TBs per PDSCH reception of CC#1. As a result, the number of generated HARQ-ACK bits (N 21 、N 22 、N 23 and N 24 ) is 1 bit per PDSCH.

[0423] As a fourth method, similar to the second method, the UE can generate a semi-static HARQ-ACK codebook by spatially bundling one by one in sequence the cells in which two-TB reception per PDSCH is configured, and can determine whether transmission is possible.

[0424] The following preferred embodiment can be configured by combining the first method and the third method. In this preferred embodiment, the UE generates a semi-static HARQ-ACK codebook by assuming TB-based PDSCH reception in the cell in which CBG-based PDSCH reception is configured, and checks whether the semi-static HARQ-ACK codebook can be transmitted. If transmission is not possible, it checks whether the semi-static HARQ-ACK codebook generated by additionally performing spatial bundling can be transmitted.

[0425] The detailed operations are described as follows. When configuring CBG-based PDSCH reception and reception of 2 TBs per PDSCH in a cell, the UE generates a semi-static HARQ-ACK codebook by assuming the CBG-based PDSCH reception as the TB-based PDSCH reception in the cell. When the size of the semi-static HARQ-ACK codebook generated by assuming the TB-based PDSCH reception is equal to or less than the number of bits that can be transmitted (here B bits), the UE can transmit the semi-static HARQ-ACK codebook. Otherwise, the UE performs additional spatial bundling by bundling the HARQ-ACK bits of two TBs in the cell to generate one bit, and generates a semi-static HARQ-ACK codebook based on the above bit. If the size of the semi-static HARQ-ACK codebook generated based on the spatially bundled bit is equal to or less than the number of bits that can be transmitted (here B bits), the UE can transmit the semi-static HARQ-ACK codebook. If the size of the semi-static HARQ-ACK codebook generated based on the spatially bundled bit is greater than the number of bits that can be transmitted (here B bits), the UE cannot transmit the semi-static HARQ-ACK codebook. In this case, additional HARQ-ACK bits need to be discarded or bundled. This will be described later.

[0426] Refer to Figure 28 (a), (b), and (d) of, first, according to the first method, the UE generates a semi-static HARQ-ACK codebook by assuming TB-based HARQ-ACK to reduce the number of HARQ-ACK bits (M 21 、M 22 、M 23 and M 34 ) generated for the CBG-based PDSCH reception according to CC#2. The resulting number of HARQ-ACK bits (N 21 、N 22 、N 23 and N 24 ) is 1 bit per PDSCH. If the number of bits in the semi-static HARQ-ACK codebook is greater than the number of bits that the UE can transmit, the third method is additionally performed. According to the third method, the UE can spatially bundle the ACK / NACKs of 2 TBs of one PDSCH to reduce the number of HARQ-ACK bits (L 21 、L 22 、L 23 and L 34 ) generated for the reception configuration of 2 TBs per PDSCH according to CC#1. The resulting number of HARQ-ACK bits (N 21 、N 22 、N 23 and N 24) is 1 bit per PDSCH. The semi-static HARQ-ACK codebook generated due to the first method and the third method includes 1-bit HARQ-ACK per PDSCH.

[0427] Through the first method to the fourth method, the UE can equally have HARQ-ACK bits of 1 bit per PDSCH for each cell. If the size of the semi-static HARQ-ACK codebook is greater than the number of bits that the UE can send after performing the first method to the fourth method, additional HARQ-ACK bits need to be discarded or bundled. For reference, the discarding or bundling of HARQ-ACK bits described later can be additionally applied to the first method to the fourth method. Unless otherwise specified, even when the first method to the fourth method is not used (i.e., when the HARQ-ACK codebook includes multiple HARQ-ACK bits per PDSCH), the discarding or bundling of HARQ-ACK bits described later can be used.

[0428] As a fifth embodiment, the UE can generate a semi-static HARQ-ACK codebook including HARQ-ACK bits of some cells and can send the semi-static HARQ-ACK codebook. Here, some cells can be selected based on the cell index.

[0429] Figure 29 is a diagram illustrating a method for reducing the HARQ-ACK size in the case of carrier aggregation according to an embodiment of the present invention.

[0430] Referring to Figure 29 of (a), if the UE is configured to receive PDSCH from three cells CC#0, CC#1, and CC#2, the UE can generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of CC#0. However, if the number of bits (N 01 +N 02 +N 03 +N 04 ) of the semi-static HARQ-ACK codebook is greater than the number of bits that the UE can send, the UE cannot send the semi-static HARQ-ACK codebook. In this case, additional discarding or bundling should be performed within one cell. The methods of the above Embodiments 1 to 4 can be applied here. In addition, if the number of bits (N 01 +N 02 +N 03 +N 04) is equal to or less than the number of bits that the UE can transmit, the UE can transmit a semi-static HARQ-ACK codebook. In addition, the UE can generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of cell CC#1 with the next index. If the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 02 +N 03 +N 04 +N 11 +N 12 +N 13 +N 14 ) is equal to or less than the number of bits that the UE can transmit, the UE can transmit a semi-static HARQ-ACK codebook. If the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 02 +N 03 +N 04 +N 11 +N 12 +N 13 +N 14 ) is greater than the number of bits that the UE can transmit, the UE can generate a semi-static HARQ-ACK codebook generated using cells up to the previous index except for cell CC#1.

[0431] As a sixth embodiment, the UE can generate a semi-static HARQ-ACK codebook including HARQ-ACK bits corresponding to some time slots, and can transmit the semi-static HARQ-ACK codebook. Here, some time slots can be selected based on the K1 value.

[0432] Referring to Figure 29 (b) of, if the UE is configured to receive PDSCH in four time slots n-K1(1), n-K1(2), n-K1(3), and n-K1(4) determined according to four K1 values K1(1), K1(2), K1(3), and K1(4), the UE can generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of the first time slot n-K1(1). However, if the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 11 +N 21 ) is greater than the number of bits that the UE can transmit, the UE cannot transmit the semi-static HARQ-ACK codebook. In addition, if the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 11 +N 21) is less than or equal to the number of bits that the UE can transmit, the UE can transmit a semi-static HARQ-ACK codebook. In addition, the UE can generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of the next time slot n-K1(2). If the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 11 +N 21 +N 02 +N 12 +N 22 ) is less than or equal to the number of bits that the UE can transmit, the UE can transmit a semi-static HARQ-ACK codebook. If the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 11 +N 21 +N 02 +N 12 +N 22 ) is greater than the number of bits that the UE can transmit, the UE can generate a semi-static HARQ-ACK codebook generated using previous time slots other than time slot n-K1(2).

[0433] In the fifth and sixth embodiments, the UE excludes the HARQ-ACK bits of a specific cell or the HARQ-ACK bits of a specific time slot. However, when excluding the HARQ-ACK bits of a specific cell, not all time slots of that cell may be excluded. In addition, when excluding the HARQ-ACK bits of a specific time slot, not all cells of that time slot may be excluded.

[0434] As in the fifth embodiment, the UE can generate a semi-static HARQ-ACK codebook configured with the HARQ-ACK bits of some cells. Here, when adding the HARQ-ACK bits of a specific cell to the semi-static HARQ-ACK codebook, the UE can sequentially add the HARQ-ACK bits of each time slot of the specific cell. When adding all the HARQ-ACK bits of all time slots of a specific cell or adding the HARQ-ACK bits of a certain time slot, the addition process can be performed until it exceeds the number of bits that the UE can transmit. If the number of bits that the UE can transmit is exceeded when adding the HARQ-ACK bits of a certain time slot, the semi-static HARQ-ACK codebook in which the HARQ-ACK bits up to the previous time slot of that time slot are added can be transmitted. This scheme can be called the K1 value first, CC second scheme.

[0435] Refer to Figure 29In (c), the UE may generate a semi-static HARQ-ACK codebook configured with HARQ-ACK bits for CC#0. This semi-static HARQ-ACK codebook includes N 01 +N 02 +N 03 +N 04 bits. The HARQ-ACK bits for CC#1 of the next cell may be added to the semi-static HARQ-ACK codebook in the order of the time slots of cell CC#1. First, it may be determined whether to add the HARQ-ACK bits (N 11 bits) of time slot n-K1(1) corresponding to the K1(1) value to the semi-static HARQ-ACK codebook. If the number of bits in the semi-static HARQ-ACK codebook after adding the above HARQ-ACK bits is equal to or less than the number of bits that the UE can transmit, the above HARQ-ACK bits may be added to the semi-static HARQ-ACK codebook. Next, it may be determined whether to add the HARQ-ACK bits of the next time slot n-K1(2). If the number of bits in the semi-static HARQ-ACK codebook after adding the above HARQ-ACK bits is greater than the number of bits that the UE can transmit, the above HARQ-ACK bits are not added to the semi-static HARQ-ACK codebook. In this way, it may be determined whether to add the HARQ-ACK bits of the last time slot n-K1(4).

[0436] As in the sixth embodiment, the UE may generate a semi-static HARQ-ACK codebook configured with HARQ-ACK bits for some time slots. Here, when adding the HARQ-ACK bits of a specific time slot to the semi-static HARQ-ACK codebook, the UE may sequentially add the HARQ-ACK bits of each cell of the specific time slot. When adding all the HARQ-ACK bits of all cells of a specific time slot or adding the HARQ-ACK bits of a certain cell, this addition process may be performed until it exceeds the number of bits that the UE can transmit. If it exceeds the number of bits that the UE can transmit when adding the HARQ-ACK bits of a certain cell, the semi-static HARQ-ACK codebook in which the HARQ-ACK bits of the previous cell up to that cell are added may be transmitted. This scheme may be referred to as the CC first K1 value second scheme.

[0437] Referring to Figure 29 In (d), the UE may generate a semi-static HARQ-ACK codebook configured with HARQ-ACK bits for time slot n-K1(2). This semi-static HARQ-ACK codebook includes N 01 +N 11 +N 21 +N 02 +N 12 +N 22Bits. The HARQ-ACK bits for time slot n-K1(3) as the next time slot can be added to the semi-static HARQ-ACK codebook in the order of the cells of time slot n-K1(3). First, it can be determined whether to add the HARQ-ACK bits (N 03 bits) of cell CC#0 with the lowest index to the semi-static HARQ-ACK codebook. If the number of bits in the semi-static HARQ-ACK codebook after adding the above HARQ-ACK bits is equal to or less than the number of bits that the UE can transmit, the above HARQ-ACK bits can be added to the semi-static HARQ-ACK codebook. Next, it can be determined whether to add the HARQ-ACK bits of the next-index cell CC#1. If the number of bits in the semi-static HARQ-ACK codebook after adding the above HARQ-ACK bits is greater than the number of bits that the UE can transmit, the above HARQ-ACK bits are not added to the semi-static HARQ-ACK codebook. In this way, it can be determined whether to add the HARQ-ACK bits of the cell with the last index.

[0438] When the UE generates a semi-static HARQ-ACK codebook, multiple bits can correspond to one time slot. Another method proposed in the present invention is a method for reducing multiple bits when multiple bits correspond to one time slot. Regarding the above first to fourth embodiments, a discarding scheme has been described, in which the UE transmits some HARQ-ACK bits and does not transmit other HARQ-ACK bits. Hereinafter, a bundling scheme instead of the discarding scheme will be described.

[0439] Figure 30 is a diagram illustrating a method for reducing the HARQ-ACK size within one time slot according to an embodiment of the present invention. In particular, Figure 30 illustrates that three PDSCH candidates are configured in one time slot.

[0440] - PDSCH candidate A occupies symbols 0 to 13,

[0441] - PDSCH candidate B occupies symbols 0 to 6,

[0442] - PDSCH candidate C occupies symbols 7 to 13.

[0443] A UE can receive only one PDSCH on one symbol, and thus PDSCH candidate A and PDSCH candidate B cannot be scheduled for reception simultaneously because the PDSCH candidates overlap in symbols 0 to 6. In addition, PDSCH candidate A and PDSCH candidate C overlap in symbols 7 to 13, and thus cannot be scheduled for reception simultaneously. Therefore, the UE can be scheduled to receive only PDSCH candidate A or one or both of PDSCH candidate B and PDSCH candidate C. This can be simply expressed as follows.

[0444] -{A}, {B}, {C}

[0445] -{B, C}

[0446] Reference Figure 30 , by definition, a type-1 HARQ-ACK codebook can be configured with HARQ-ACK bits for at most two PDSCHs per time slot. For convenience, assume that the HARQ-ACK for a PDSCH is 1 bit. That is, the type-1 HARQ-ACK codebook is configured with 2 bits for HARQ-ACK information for at most two PDSCHs per time slot. This is referred to as [b0b1]. Here,

[0447] - b0 can send HARQ-ACK information for PDSCH candidate A and PDSCH candidate B.

[0448] - b1 can send HARQ-ACK information for PDSCH candidate C.

[0449] Assume that the UE has received PDSCH candidate A. This can include the case where the PDCCH scheduling PDSCH candidate A has been received or an SPS PDSCH is configured in PDSCH candidate A. As described above, if PDSCH candidate A is scheduled, other PDSCH candidates cannot be scheduled. That is, since PDSCH candidate C corresponding to b1 cannot be scheduled, b1 should always send a NACK. In other words, if PDSCH candidate A is scheduled, the type-1 HARQ-ACK codebook includes [b0 NACK]. Here, the HARQ-ACK bit of the PDSCH received in PDSCH candidate A can be mapped to b0.

[0450] The UE can perform bundling to reduce the HARQ-ACK information of the PDSCHs received in one time slot of the type-1 HARQ-ACK codebook. In the above example, [b0 b1] may be bundled into one bit. Here, bundling can be defined as follows.

[0451] - If the HARQ-ACK of all bits (b0 and b1) is ACK, then it is ACK

[0452] - Otherwise, if the HARQ-ACK of at least one of all the bits (b0 and b1) is NACK, then it is NACK

[0453] In the above example, when it is assumed that PDSCH candidate A has been received, [b0b1] is given such that [b0 b1] = [b0 NACK]. Therefore, when bundling two bits (b0 and b1), the result is always NACK. This result is obtained regardless of whether PDSCH candidate A has been successfully received. Therefore, the type-1 HARQ-ACK codebook generated as a result of the above bundling process cannot convey information about whether PDSCH has been successfully received. The present invention proposes a method to solve this problem.

[0454] A method for bundling a type-1 HARQ-ACK codebook according to an embodiment of the present invention is described below.

[0455] - For a bit position in the type-1 HARQ-ACK codebook, if a PDSCH is received and all corresponding PDSCH candidates associated with this bit position overlap with the received PDSCH, then this bit position is considered as "X (the third state)" for bundling

[0456] o Rule A) When bundling, 'X' is regarded as "ACK" and the bundling that only includes bits of 'X'' is NACK.

[0457] o Rule B) First remove 'X', and bundle the remaining states. After bundling, if the bit size is smaller than the expected size, then add NACK

[0458] Reference Figure 30 The bundling according to the above embodiment is described as follows.

[0459] According to [b0 b1], the UE can recognize that when receiving the scheduling information of PDSCH candidate A, PDSCH candidate B and PDSCH candidate C cannot be scheduled. Therefore, the ACK / NACK indicating whether PDSCH candidate A has been successfully received can be mapped to the b0 bit, and "X (the third state)" can be mapped to the b1 bit because PDSCH candidate C cannot be scheduled. That is to say, this can be expressed as [b0 b1] = [b0 X].

[0460] According to Rule A, 'X' is regarded as ACK when performing bundling. Therefore, if b0 and X are bundled into 1 bit, the bundled 1 bit is b0.

[0461] According to Rule B, 'X' is excluded. If it is excluded, the result is [b0]. Therefore, when bundled into 1 bit, the bundled 1 bit is b0.

[0462] After receiving the bundled 1 bit, the base station can identify that the bundled 1 bit is the HARQ-ACK of PDSCH candidate A by using the information that has scheduled PDSCH candidate A.

[0463] Figure 31 FIG. is a diagram of a method for reducing the size of HARQ-ACK within a time slot according to an embodiment of the present invention. In particular, Figure 31 illustrates that seven PDSCH candidates are configured in a time slot.

[0464] - PDSCH candidate A occupies symbols 0 to 13,

[0465] - PDSCH candidate B occupies symbols 0 to 6,

[0466] - PDSCH candidate C occupies symbols 7 to 13.

[0467] - PDSCH candidate D occupies symbols 0 to 3,

[0468] - PDSCH candidate E occupies symbols 4 to 7,

[0469] - PDSCH candidate F occupies symbols 8 to 11,

[0470] - PDSCH candidate G occupies symbols 12 and 13.

[0471] According to the type-1 HARQ-ACK codebook generation method, 4-bit HARQ-ACK bits can be generated for the PDSCH candidates in this time slot. This is referred to as [b0 b1 b2 b3]. Here,

[0472] - b0 can send the HARQ-ACK information of PDSCH candidate A, PDSCH candidate B, or PDSCH candidate D.

[0473] - b1 can send the HARQ-ACK information of PDSCH candidate C or PDSCH candidate E.

[0474] - b2 can send the HARQ-ACK information of PDSCH candidate F.

[0475] - b3 can send the HARQ-ACK information of PDSCH candidate G.

[0476] The combinations that allow the UE to be scheduled simultaneously within a time slot can be expressed as follows.

[0477] o {A}, {B}, {C}, {D}, {E}, {F}, {G}

[0478] o{B,C},{B,F},{B,G},{C,D},{D,E},{D,F},{D,G},{E,F},{E,G},{F,G}

[0479] o{B,F,G},{D,E,F},{D,E,G},{D,F,G},{E,F,G}

[0480] o{D,E,F,G}

[0481] The UE can bundle 4 bits into 2 bits or 1 bit to reduce the number of bits in the semi-static HARQ-ACK codebook. Table 7 shows 2-bit bundling and 1-bit bundling. Here, the bundling is obtained by performing a binary AND operation on adjacent ACK / NACKs. (ACK = 1, NACK = 0). That is, in the case of 2-bit bundling, the first bit is obtained by performing a binary AND operation on the first 2 bits among the 4 bits, and the second bit is obtained by performing a binary AND operation on the subsequent 2 bits. In the case of 1-bit bundling, one bit is obtained by performing a binary AND operation on the 4 bits.

[0482] In Table 7, b01 is the result of performing a binary AND operation on b0 and b1, and b23 is the result of performing a binary AND operation on b2 and b3, and b0123 is the result of performing a binary AND operation on b0, b1, b2, and b3. N represents NACK.

[0483] As shown in Table 7, in the case of 1-bit bundling, the UE always sends NACK, except when the PDSCH candidates {D, E, F, G} are scheduled. Therefore, the information that can be sent by 1-bit bundling is limited. In the case of 2-bit bundling, the UE always sends [NACK NACK], except when {B,C}, {C,D}, {D,E}, {F,G}, {B,F,G}, {D,E,F}, {D,E,G}, {D,F,G}, {E,F,G}, and {D,E,F,G} are scheduled.

[0484] [Table 7]

[0485]

[0486]

[0487] Table 8 and Table 9 show HARQ-ACK bundling according to embodiments of the present invention. Rule A is used in Table 8, and Rule B is used in Table 9.

[0488] Referring to Table 8 and Table 9, the UE can determine 'X (third state)' for bundling based on the received scheduling information. This is indicated in the column of HARQ-ACK including X (third state) for bundling. For example, when the UE receives scheduling information corresponding to PDSCH candidate A, the UE can determine b1, b2, and b3 as X (third state) because the PDSCH candidates whose HARQ-ACKs are mapped to b1, b2, and b3 cannot be scheduled.

[0489] Referring to Table 8, the UE can bundle 4-bit HARQ-ACK including X (third state) for bundling into 1 bit based on Rule A. According to Rule A, X (third state) is regarded as ACK when bundled with other ACK / NACKs. In addition, when bundling between X (third states), X (third state) is regarded as NACK. In Table 8, b023 is the result of performing a binary AND operation on b0, b2, and b3.

[0490] As shown in Table 8, in the case of 1-bit bundling, the UE sends NACK except when PDSCH candidates {A}, {B,C}, {C,D}, {B,F,G}, and {D,E,F,G} are scheduled. Compared with Table 7, when PDSCH candidates {A}, {B,C}, {C,D}, and {B,F,G} are scheduled, meaningful ACK / NACKs can be sent. In the case of 2-bit bundling, the UE sends NACK except when PDSCH candidates {A}, {B,C}, {B,F}, {C,D}, {D,E}, {F,G}, {B,F,G}, {D,E,F}, {D,E,G}, {D,F,G}, {E,F,G}, and {D,E,F,G} are scheduled. Compared with Table 7, when PDSCH candidates {A}, {B,F}, and {B,F,G} are scheduled, meaningful ACK / NACKs can be sent.

[0491] [Table 8]

[0492]

[0493]

[0494] Referring to Table 8, the UE can generate a HARQ-ACK removing X (third state) for bundling by excluding 'X (third state)' from the 4-bit HARQ-ACK including X (third state) for bundling. Further, if the HARQ-ACK removing X (third state) for bundling is greater than the number of bits after bundling, bundling can be performed by performing a binary AND operation on some bits. If the HARQ-ACK removing X (third state) for bundling is less than the number of bits after bundling, NACK can be filled in later. For example, in the case of 2-bit bundling, if the HARQ-ACK removing X (third state) for bundling is 1 bit, the HARQ-ACK is made 2 bits by filling NACK after the 1 bit. In the case of 2-bit bundling, if the HARQ-ACK removing X (third state) for bundling is 2 bits, these 2 bits are the result of bundling. In the case of 2-bit bundling, if the HARQ-ACK removing X (third state) for bundling is 3 bits, 1 bit is obtained by performing a binary AND operation on the first 2 bits, and this bit is added to the last bit of the HARQ-ACK removing X (third state) for bundling, so as to obtain 2 bits as the result of bundling. In Table 9, b023 is the result of performing a binary AND operation on b0, b2, and b3, and b02 is the result of performing a binary AND operation on b0 and b2.

[0495] As shown in Table 9, in the case of 1-bit bundling, the UE sends NACK except when the PDSCH candidates {A}, {B,C}, {C,D}, {B,F,G}, and {D,E,F,G} are scheduled. Compared with Table 7, when the PDSCH candidates {A}, {B,C}, {C,D}, and {B,F,G} are scheduled, meaningful ACK / NACK can be sent. In the case of 2-bit bundling, the UE sends NACK except when the PDSCH candidates {A}, {C}, {B,C}, {B,F}, {C,D}, {D,E}, {F,G}, {B,F,G}, {D,E,F}, {D,E,G}, {D,F,G}, {E,F,G}, and {D,E,F,G} are scheduled. Compared with Table 7, when the PDSCH candidates {A}, {B,F}, and {B,F,G} are scheduled, meaningful ACK / NACK can be sent. Compared with Table 8, meaningful ACK / NACK can be sent when the PDSCH candidate {C} is scheduled.

[0496] [Table 9]

[0497]

[0498] Based on 1-bit bundling, the following operations can be considered. In the case of 1-bit bundling, when the UE receives the scheduling information of a PDSCH in a time slot, the UE can use the success / failure of the received PDSCH as the result value of 1-bit bundling.

[0499] Referring to Table 10, when the UE receives the scheduled PDSCH candidates {A}, {B}, {C}, {D}, {E}, {F}, and {G}, the UE can use the HARQ-ACK of the PDSCH as the result value of 1-bit bundling because one PDSCH is scheduled in the time slot. If two or more PDSCH candidates are scheduled, NACK can be used as the result value of 1-bit bundling. For another example, if two or more PDSCH candidates are scheduled, the 1-bit bundling can be obtained using the schemes in Table 8 and Table 9.

[0500] [Table 10]

[0501] Index Received PDSCH HARQ-ACK Proposed bundling (1-bit bundling) 1 {A} [b0 N N N] [b0] 2 {B} [b0 N N N] [b0] 3 {C} [N b1 N N] [b1] 4 {D} [b0 N N N] [b0] 5 {E} [N b1 N N] [b1] 6 {F} [N N b2 N] [b2] 7 {G} [N N N b3] [b3] 8 {B,C} [b0 b1 N N] [N] 9 {B,F} [b0 N b2 N] [N] 10 {B,G} [b0 N N b3] [N] 11 {C,D} [b0 b1 N N] [N] 12 {D,E} [b0 b1 N N] [N] 13 {D,F} [b0 N b2 N] [N] 14 {D,G} [b0 N N b3] [N] 15 {E,F} [N b1 b2 N] [N] 16 {E,G} [N b1 N b3] [N] 17 {F,G} [N N b2 b3] [N] 18 {B,F,G} [b0 N b2 b3] [N] 19 {D,E,F} [b0 b1 b2 N] [N] 20 {D,E,G} [b0 b1 N b3] [N] 21 {D,F,G} [b0 N b2 b3] [N] 22 {E,F,G} [N b1 b2 b3] [N] 23 {D,E,F,G} [b0 b1 b2 b3] [N]

[0502] Assume that the number of bits of the HARQ-ACK codebook of the UE is given as A bits. In addition, assume that the number of bits that the UE can transmit is given as B bits. The UE can bundle the A bits to generate B bits or fewer than B bits. Here, the specific bundling scheme will be described.

[0503] As a first method, the UE bundles every X bits starting from the first bit of the HARQ-ACK codebook. Here, X is preferably ceil(A / B). The number of bundles is ceil(A / ceil(A / B)). For reference, if A is a multiple of ceil(A / B), all bundles are ceil(A / B) bits, but if A is not a multiple of ceil(A / B), the last bundle is A mod ceil(A / B) bits. By performing a binary AND operation on the bits included in each bundle, 1 bit is generated for each bundle.

[0504] For example, assume that the HARQ-ACK codebook is A = 10 bits (hereinafter [b0 b1 b2 b3 b4 b5 b6 b7 b8 b9]), and the number of bits that the UE can transmit is given as B = 3 bits. According to the first method, the UE bundles every ceil(10 / 3) = 4 bits starting from the front bits of the HARQ-ACK codebook. The first bundle is [b0 b1 b2 b3], the second bundle is [b4 b5 b6 b7], and the third bundle is [b8 b9]. Therefore, after bundling, the first bit is the value obtained by performing a binary AND operation on [b0 b1 b2 b3], the second bit is the value obtained by performing a binary AND operation on [b4 b5 b6 b7], and the third bit is the value obtained by performing a binary AND operation on [b8 b9].

[0505] As another example of the first method, the UE bundles every X bits starting from the front bits of the HARQ-ACK codebook. Here, X is one of the powers of 2 and is equal to or greater than ceil(A / B).

[0506] As the second method, the UE bundles ceil(A / B) bits and floor(A / B) bits of the HARQ-ACK codebook. The number of bundles of ceil(A / B) bits is A mod B, and the number of bundles of floor(A / B) bits is B - (A mod B). By performing a binary AND operation on the bits included in each bundle, 1 bit is generated for each bundle.

[0507] For example, assume that the HARQ-ACK codebook is A = 10 bits (hereinafter [b0 b1 b2 b3 b4 b5 b6 b7 b8 b9]), and the number of bits that the UE can transmit is given as B = 3 bits. According to the second method, the UE can configure the HARQ-ACK codebook to include one bundle of ceil(10 / 3) = 4 bits and two bundles each including floor(10 / 3) = 3 bits. The first bundle is [b0 b1 b2 b3], the second bundle is [b4 b5 b6], and the third bundle is [b7 b8 b9]. Therefore, after bundling, the first bit is the value obtained by performing a binary AND operation on [b0 b1 b2 b3], the second bit is the value obtained by performing a binary AND operation on [b4 b5 b6], and the third bit is the value obtained by performing a binary AND operation on [b7 b8 b9].

[0508] As a third method, the UE divides the HARQ-ACK codebook into B - 1 bits and A - (B - 1) bits. Additionally, 1 bit is generated by performing a binary AND operation on the A - (B - 1) bits. For the HARQ-ACK codebook, the UE generates B bits by combining the B - 1 bits and the 1 bit generated above.

[0509] For example, assume the HARQ-ACK codebook is A = 10 bits ([b0 b1 b2 b3 b4 b5 b6 b7 b8 b9] hereinafter), and the number of bits that the UE can transmit is given as B = 3 bits. According to the third method, the UE can divide the HARQ-ACK codebook into 2 bits and 8 bits. The 2 bits are [b0 b1], and the 8 bits are [b2 b3 b4 b5 b6 b7 b8 b9]. The UE can generate 1 bit by performing a binary AND operation on the 8 bits, and can generate B = 3 bits by combining the 1 bit with [b0 b1].

[0510] As a reference, if A is a multiple of ceil(A / B), then all bundles are ceil(A / B) bits, but if A is not a multiple of ceil(A / B), then the last bundle is A mod ceil(A / B) bits. By performing a binary AND operation on the bits included in each bundle, 1 bit is generated for each bundle.

[0511] The foregoing description of the present disclosure is for illustrative purposes, and those skilled in the art to which the present disclosure pertains will be able to understand that other specific forms of modification can be easily implemented without changing the technical spirit or essential features of the present disclosure. Therefore, it should be understood that the above embodiments are exemplary in all aspects and not restrictive. For example, each element described as a single type can be implemented in a distributed manner, and similarly, elements described as distributed can also be implemented in a combined form.

[0512] The scope of the present disclosure is indicated by the claims to be described hereinafter rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included within the scope of the present disclosure.

Claims

1. A user equipment (UE) configured to operate in a wireless communication system, the UE comprising: A processor; And A communication module, Wherein, the processor is configured to: Receive downlink control information (DCI) for downlink scheduling, where the DCI includes a sub-slot offset, and the sub-slot offset is an element of a set K: {k0, k1,..., k m-1}(m > 0); Generate a semi-static hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook, and for each element k of the set K i (k i > 0), perform one of the following operations: - If the first downlink (DL) slot corresponding to UL sub-slot #(n u - k i ) is different from the second DL slot corresponding to UL sub-slot #(n u - k i-1 ), include the HARQ-ACK information for the first DL slot in the semi-static HARQ-ACK codebook, and - If the first DL time slot is the same as the second DL time slot, skip including the HARQ-ACK information for the first DL time slot in the semi-static HARQ-ACK codebook; and Transmit the semi-static HARQ-ACK codebook in UL sub-slot #n u wherein Wherein, the generation of the HARQ-ACK information includes: - Based on whether the end of the corresponding PDSCH candidate in the first DL time slot is within any UL sub - slot #(n u - k o ), determine a set of valid physical downlink shared channel (PDSCH) candidates for the first DL time slot, where k o is at least a part of the set K.

2. The UE according to claim 1, wherein, The DL time slot includes 14 symbols, and the UL sub-time slot includes X symbols, where X is less than 14.

3. The UE according to claim 1, wherein, k o has a plurality of values corresponding to UL sub - slots overlapping with the first DL time slot.

4. The UE according to claim 1, wherein If the UE does not have the ability to receive more than one PDSCH per DL time slot, when there is at least one valid PDSCH candidate in the first DL time slot, the HARQ-ACK information for the first DL time slot includes the HARQ-ACK information for only one PDSCH reception.

5. The UE according to claim 1, wherein, If the UE has the ability to receive more than one PDSCH per DL time slot, based on the set of valid PDSCH candidates, the HARQ-ACK information for the first DL time slot includes the HARQ-ACK information for one or more PDSCH receptions.

6. The UE according to claim 5, wherein, If the UE has the ability to receive more than one PDSCH per DL time slot, assign the same HARQ-ACK bit position to both: (i) the first valid PDSCH candidate with the smallest last symbol index and (ii) zero or more second valid PDSCH candidates that overlap with the first valid PDSCH candidate in time, and then remove the first valid PDSCH candidate and the zero or more second valid PDSCH candidates from the set of valid PDSCH candidates.

7. The UE according to claim 1, wherein, If multiple DL time slots are within UL sub - slot #(n u- k i ), then the first DL time slot corresponds to each of the multiple DL time slots starting from the DL time slot with the smallest index among the multiple DL time slots.

8. The UE according to claim 1, wherein Determine the end of the corresponding PDSCH candidate based on the start and length indicator value (SLIV) of the first DL time slot.

9. The UE according to claim 1, wherein, Receive the DCI via a physical downlink control channel (PDCCH).

10. The UE according to claim 1, wherein, Transmit the semi-static HARQ-ACK codebook via a physical uplink control channel (PUCCH).

11. A method used by a user equipment (UE) in a wireless communication system, the method comprising: Receive downlink control information (DCI) for downlink scheduling, where the DCI includes a sub-slot offset, and the sub-slot offset is an element of a set K: {k0, k1, ..., k m-1}(m > 0); Generate a semi-static hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook, and for each element k of the set K i (k i > 0), perform one of the following operations: - If the first downlink (DL) slot corresponding to UL sub-slot #(n u - k i ) is different from the second DL slot corresponding to UL sub-slot #(n u - k i-1 ), include the HARQ-ACK information for the first DL slot in the semi-static HARQ-ACK codebook, and - If the first DL time slot is the same as the second DL time slot, skip including the HARQ-ACK information for the first DL time slot in the semi-static HARQ-ACK codebook; and Transmit the semi-static HARQ-ACK codebook in UL sub-slot #n u wherein the semi-static HARQ-ACK codebook is transmitted Wherein, the generation of the HARQ-ACK information includes: - Based on whether the end of the corresponding PDSCH candidate in the first DL time slot is within any UL sub - slot #(n u - k o ), determine a set of valid physical downlink shared channel (PDSCH) candidates for the first DL time slot, where k o is at least a part of the set K.

12. The method according to claim 11, wherein, The DL time slot includes 14 symbols, and the UL sub-time slot includes X symbols, where X is less than 14.

13. The method according to claim 11, wherein, k o having a plurality of values corresponding to UL sub - slots overlapping with the first DL slot.

14. The method according to claim 11, wherein, If the UE does not have the ability to receive more than one PDSCH per DL time slot, when there is at least one valid PDSCH candidate in the first DL time slot, the HARQ-ACK information for the first DL time slot includes the HARQ-ACK information for only one PDSCH reception.

15. The method according to claim 11, wherein, If the UE has the ability to receive more than one PDSCH per DL time slot, then based on the set of valid PDSCH candidates, the HARQ-ACK information for the first DL time slot includes HARQ-ACK information for one or more PDSCH receptions.

16. The method according to claim 15, wherein, If the UE has the ability to receive more than one PDSCH per DL time slot, then the same HARQ-ACK bit positions are assigned to both: (i) a first valid PDSCH candidate having the smallest last symbol index and (ii) zero or more second valid PDSCH candidates that overlap in time with the first valid PDSCH candidate, and then the first valid PDSCH candidate and the zero or more second valid PDSCH candidates are removed from the set of valid PDSCH candidates.

17. The method according to claim 11, wherein, If multiple DL time slots are within UL sub - slot #(n u -k i ), then the first DL time slot corresponds to each of the multiple DL time slots starting from the DL time slot with the smallest index among the multiple DL time slots.

18. The method according to claim 11, wherein, Determine the end of the corresponding PDSCH candidate based on the start and length indicator value (SLIV) of the first DL time slot.

19. The method according to claim 11, wherein, Receive the DCI via a physical downlink control channel (PDCCH).

20. The method according to claim 11, wherein, Transmit the semi-static HARQ-ACK codebook via a physical uplink control channel (PUCCH).

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