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

Abstract

The invention relates to a method, a device and a system for generating a HARQ-ACK codebook in a wireless communication system. 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, in which the processor generates a Hybrid Automatic Repeat reQuest (HARQ)-ACK codebook including one or more bits indicating whether reception of a channel or a signal is successful, and the processor and transmits the HARQ-ACK codebook to a base station of a wireless communication system, the HARQ-ACK codebook is generated on the basis of a slot corresponding to a value of a HARQ-ACK feedback timing parameter (K1) set in a sub-slot level, and each bit of the HARQ-ACK codebook is configured to correspond to at least one sub-slot form among a plurality of sub-slots included in the slot.

Description

[0001] This application is a divisional application of the patent application with the international application date of September 27, 2021 and application number 202180071400.X (PCT / KR2021 / 013164) filed on April 19, 2023, and the invention name is “Method, device and system for generating HARQ-ACK codebook in a wireless communication system”. Technical Field

[0002] The present invention relates to a wireless communication system, and more particularly, to a method for generating a HARQ-ACK codebook for a wireless communication system and a device using the method. Background Art

[0003] Following the commercialization of the fourth generation (4G) communication system, efforts are underway to develop a new fifth generation (5G) communication system to meet the increasing demand for wireless data services. The 5G communication system is referred to as a super 4G network communication system, a post-LTE system, or a new radio (NR) system. In order to achieve high data transmission rates, the 5G communication system includes a system operating in a millimeter wave (mmWave) frequency band of 6 GHz or higher, and in terms of ensuring coverage, includes a communication system operating in a frequency band of 6 GHz or lower, so that implementation methods in base stations and terminals are under consideration.

[0004] The 3rd Generation Partnership Project (3GPP) NR system improves the spectrum efficiency of the network and enables communications providers to offer more data and voice services over a given bandwidth. Therefore, the 3GPP NR system is designed to meet the demand for high-speed data and media transmission in addition to supporting large amounts of voice. The advantages of the NR system are higher throughput and lower latency on the same platform, support for frequency division duplex (FDD) and time division duplex (TDD), and low operating costs due to an enhanced end-user environment and simple architecture.

[0005] 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 user. For example, when the downlink traffic of the cell is greater than the uplink traffic, the base station can allocate multiple downlink OFDM symbols for one time slot (or subframe). Information about the time slot configuration should be sent to the terminal.

[0006] In order to reduce the path loss of radio waves and increase the transmission distance of radio waves in the mmWave band, in 5G communication systems, beamforming, massive multiple input / 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 are being discussed. In addition, for the purpose of system network improvement, in 5G communication systems, technology development related to evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), vehicle-to-everything communication (V2X), wireless backhaul, non-terrestrial network communication (NTN), mobile networks, cooperative communication, coordinated multipoint (CoMP), interference cancellation, etc. is underway. In addition, in 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) schemes are being developed, as well as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced connection technologies.

[0007] At the same time, the Internet, a human-centric connected network where humans generate and consume information, has evolved into the Internet of Things (IoT) network, which exchanges information between distributed components such as objects. The Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology through connection to cloud servers, is also emerging. Implementing the IoT requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology. Consequently, in recent years, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) have been studied to connect objects. Within the IoT environment, intelligent Internet technology (IT) services can be provided that collect and analyze data generated by networked objects to create new value in human life. Through the integration and hybridization of existing information technology (IT) and various industries, the IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and advanced medical services.

[0008] Therefore, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communications (MTC) are implemented using technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN, a big data processing technology, is an example of the convergence of 5G and IoT technologies. Mobile communication systems are generally developed to provide voice services while ensuring user mobility.

[0009] However, the field of mobile communication systems has expanded not only to voice services but also to data services, and has now developed to provide high-speed data services. However, in the current mobile communication systems for providing services, resource shortages have occurred, and users require higher-speed services, and therefore require more advanced wireless communication systems. Summary of the Invention

[0010] Technical issues

[0011] An object of the embodiments of the present invention is to provide a method and device for efficiently generating a HARQ-ACK codebook in a wireless communication system.

[0012] Technical Solution

[0013] To achieve the above-mentioned objective, according to one aspect of the present invention, a user equipment (UE) of a wireless communication system includes: a communication module; and a processor that controls the communication module, wherein the processor generates 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 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-slot level, and each bit constituting the HARQ-ACK codebook corresponds to at least one sub-slot among a plurality of sub-slots included in the time slot.

[0014] The processor may convert the K1 value configured at the sub-slot level to a K1 value configured at the slot level, wherein the slot may be determined by the slot-level HARQ-ACK feedback timing value.

[0015] The K1 value configured at the sub-time slot level can be converted to the K1 value configured at the time slot level by the following equation: 1,k,slot , where K 1,k It can represent the K1 value configured at the sub-time slot level, k can represent the index of the K1 value configured at the sub-time slot level, K 1,k,slot It can represent the K1 value configured at the time slot level, n U may represent the index of a subslot in which a physical uplink control channel (PUCCH) is transmitted, N may represent the number of subslots in a slot, and The largest integer that can be represented by x.

[0016]

[0017] The processor can use K 1,k,slot A validity of at least one physical downlink shared channel (PDSCH) candidate for a separate time slot is determined.

[0018] The processor may determine the validity of the individual PDSCH candidates by determining at least one PDSCH candidate for each start and length indicator value (SLIV).

[0019] The processor can be based on K 1,k The descending order of determines the validity of the PDSCH candidates of the corresponding downlink time slot.

[0020] The processor may determine, for each of the at least one PDSCH candidate, validity of the at least one PDSCH candidate based on whether the last symbol is included in the first subslot.

[0021] (i) the PDSCH candidate may be determined to be valid based on the last symbol of the PDSCH candidate being included in the first subslot, and (ii) the PDSCH candidate may be determined to be invalid based on the last symbol of the PDSCH candidate being not included in the first subslot.

[0022] The first subslot may correspond to the subslot n in which the PUCCH is transmitted. U Subtract the K1 value K at the sub-slot level 1,k The value obtained.

[0023] 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 time slot used for K 1,k The HARQ-ACK codebook of the corresponding first downlink time slot.

[0024] When a first PDSCH candidate and a second PDSCH candidate subsequent to the first PDSCH candidate are valid in the first downlink time slot, based on the HARQ-ACK bits for the first downlink time slot through the first PDSCH candidate being included in the HARQ-ACK codebook, it can be determined that the HARQ-ACK bits for the second PDSCH candidate are not included in the HARQ-ACK codebook.

[0025] When a PDSCH is received in one of the first and second PDSCH candidates, the processor may transmit HARQ-ACK information of the PDSCH at a HARQ-ACK bit of a position corresponding to the first downlink slot in the HARQ-ACK codebook.

[0026] The processor may calculate all K1 values ​​configured at the subslot level corresponding to the K1 value converted into the slot level, and determine validity of at least one PDSCH candidate based on all calculated K1 values ​​configured at the subslot level.

[0027] The processor can calculate a set of K1 values ​​at the time slot level based on a set of multiple K1 values ​​configured at the sub-time slot level, and generate a HARQ-ACK codebook by determining the validity of at least one PDSCH candidate of the corresponding downlink time slot according to the descending order of the K1 values ​​configured at the time slot level in the calculated set of K1 values ​​configured at the time slot level.

[0028] 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) may subsequently determine the validity of a PDSCH candidate for a DL slot corresponding to a second slot-level K1 value less than the first slot-level K1 value.

[0029] The processor may determine the validity of the first PDSCH candidate based on whether a last symbol of the first PDSCH candidate in the first downlink slot corresponding to the first slot-level K1 value is included in a second subslot calculated using the first slot-level K1 value.

[0030] The processor may determine that the PDSCH candidate is valid based on the last symbol of the PDSCH candidate being included in at least one of the second subslots, and determine that the PDSCH candidate is invalid based on the last symbol of the PDSCH candidate not being included in the second subslot.

[0031] The second subslot may correspond to the subslot n in which the PUCCH is transmitted. U A value obtained by subtracting at least one K1 value configured at a subslot level, which corresponds to the first slot level K1 value.

[0032] The HARQ-ACK codebook may be a semi-static HARQ-ACK codebook that 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 successful / failed reception.

[0033] To achieve the above-mentioned objective, 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 time slot corresponding to a HARQ-ACK feedback timing parameter (K1) value configured at a sub-time slot level.

[0034] The step of generating the HARQ-ACK codebook may include the steps of converting the HARQ-ACK feedback timing parameter (K1) value configured at the time slot level into a time slot level HARQ-ACK feedback timing value, and determining the time slot by the time slot level HARQ-ACK feedback timing value.

[0035] The step of generating the HARQ-ACK codebook may include: using the K1 value K converted at the time slot level 1,k,slot , determining validity of at least one physical downlink shared channel (PDSCH) candidate for a separate time slot.

[0036] The step of generating the HARQ-ACK codebook may include the step of determining, for each of the at least one PDSCH candidate, validity of the at least one PDSCH candidate based on whether a last symbol is included in the first subslot.

[0037] Beneficial effects

[0038] According to an embodiment of the present invention, the UE may transmit a PUCCH including two or more HARQ-ACKs in one time slot, and at this time, the coverage of the PUCCH may be increased by reducing the amount of HARQ-ACKs that each PUCCH may have. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 An example of a radio frame structure used in a wireless communication system is illustrated.

[0040] Figure 2 An example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system is illustrated.

[0041] Figure 3 This is a diagram for explaining physical channels used in the 3GPP system and a typical signal transmission method using the physical channels.

[0042] Figure 4a and 4b The diagram illustrates a synchronization signal / physical broadcast channel (SS / PBCH) block used for initial cell access in a 3GPP NR system.

[0043] Figure 5a and 5b Illustration of a process for transmitting control information and control channels in a 3GPP NR system.

[0044] Figure 6 Illustration of a control resource set (CORESET) in which a physical downlink control channel (PUCCH) can be transmitted in a 3GPP NR system.

[0045] Figure 7A method for configuring a PDCCH search space in a 3GPP NR system is illustrated.

[0046] Figure 8 is a conceptual diagram illustrating carrier aggregation.

[0047] Figure 9 It is a diagram for explaining signal carrier communication and multi-carrier communication.

[0048] Figure 10 is a diagram showing an example in which a cross-carrier scheduling technology is applied.

[0049] Figure 11 is a block diagram illustrating the configuration of a UE and a base station according to an embodiment of the present disclosure.

[0050] Figure 12 is a diagram illustrating a process for generating a semi-static HARQ-ACK codebook according to an embodiment of the present invention.

[0051] Figure 13 is a diagram illustrating a method of transmitting a PUCCH according to a PDSCH group indicator according to an embodiment of the present invention.

[0052] Figure 14 is a diagram illustrating a case where a collision occurs when a PUCCH is transmitted according to a PDSCH group indicator according to an embodiment of the present invention.

[0053] Figure 15 is a diagram illustrating a method of transmitting a PUCCH when a unit of K1 is a half slot according to an embodiment of the present invention.

[0054] Figure 16 is a diagram illustrating a case where a collision occurs when a PUCCH is transmitted when the unit of K1 is a half slot according to an embodiment of the present invention.

[0055] Figure 17 is a diagram illustrating a method of transmitting a PUCCH according to a HARQ-ACK multiplexing indicator according to an embodiment of the present invention.

[0056] Figure 18 is a diagram illustrating a HARQ-ACK multiplexing method using a PRI when a PUCCH is transmitted according to a HARQ-ACK multiplexing indicator according to an embodiment of the present invention.

[0057] Figure 19 is a diagram illustrating a method of transmitting a PUCCH when K1 and PRI fields do not exist according to an embodiment of the present invention.

[0058] Figure 20 It is a diagram showing how PDSCH candidates are arranged in a slot.

[0059] Figure 21 is a diagram illustrating a process of excluding overlapping PDSCH candidates according to an embodiment of the present invention.

[0060] Figure 22 is a diagram illustrating a process of generating Type 1 HARQ-ACK according to an embodiment of the present invention.

[0061] Figure 23 is a diagram illustrating a process of generating Type 1 HARQ-ACK according to an embodiment of the present invention.

[0062] Figure 24 is a diagram illustrating a method of configuring PDSCH candidates and DL association sets (or PDSCH candidate sets) when receiving a PDSCH according to an embodiment of the present invention.

[0063] Figure 25 is a diagram illustrating a method of reducing a HARQ-ACK size according to an embodiment of the present invention.

[0064] Figure 26 is a diagram illustrating a method of reducing a HARQ-ACK size according to an embodiment of the present invention.

[0065] Figure 27 is a diagram illustrating a method of reducing a HARQ-ACK size according to an embodiment of the present invention.

[0066] Figure 28 is a diagram illustrating a method of reducing a HARQ-ACK size in case of carrier aggregation according to an embodiment of the present invention.

[0067] Figure 29 is a diagram illustrating a method of reducing a HARQ-ACK size in case of carrier aggregation according to an embodiment of the present invention.

[0068] Figure 30 is a diagram illustrating a method of reducing a HARQ-ACK size within one slot according to an embodiment of the present invention.

[0069] Figure 31 is a diagram illustrating a method of reducing a HARQ-ACK size within one slot according to an embodiment of the present invention. DETAILED DESCRIPTION

[0070] The terms used in this specification are generally used, as much as possible, based on the functions of the present invention. However, these terms may be changed according to the intentions, customs, and new technologies of those skilled in the art. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in such cases, their meanings will be described in the corresponding description of the present invention. Therefore, it is intended that the terms used in this specification should not be analyzed based solely on the name of the term, but should be analyzed based on the substantive meaning of the term and content throughout the specification.

[0071] Throughout the specification and the claims that follow, when it is described that an element is “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. In addition, unless explicitly described to the contrary, the word “include” will be understood to imply the inclusion of the elements stated and not 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 value may be appropriately replaced with “greater than” or “less than”, respectively.

[0072] The following technologies can be used in various wireless access systems: 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). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using 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 that are requirements of IMT-2020. For clarity of description, 3GPP NR is mainly described, but the technical idea of ​​the present invention is not limited thereto.

[0073] Unless otherwise specified herein, a base station may include a next-generation Node B (gNB) defined in 3GPP NR. Furthermore, unless otherwise specified, a terminal may include a user equipment (UE). Hereinafter, to aid understanding of the description, each content is described separately through an embodiment, but each embodiment may be used in combination. In this specification, the configuration of the UE may refer to the configuration by the base station. More specifically, the base station may configure the values ​​of parameters used in the operation of the UE or the wireless communication system by transmitting a channel or signal to the UE.

[0074] Figure 1 An example of a radio frame structure used in a wireless communication system is illustrated.

[0075] refer to Figure 1 , the radio frame (or radio frame) used in the 3GPP NR system may have a 10ms (Δf max N f / 100)*T c ) length. In addition, the wireless frame consists of 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 can be assigned to 10 subframes within a radio frame. Each subframe is 1ms long and can 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, 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz can be used for subcarrier spacing. One subframe with a length of 1ms may include 2 μ In this case, the length of each time slot is 2 -μ ms. It can be set from 0 to 2 μ -1 are assigned to the 2 μ In addition, the time slots from 0 to 10*2 μ Numbers of -1 are assigned to time slots within a 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).

[0076] Figure 2 An example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system is shown. In particular, Figure 2 The structure of the resource grid of the 3GPP NR system is shown.

[0077] There is one resource grid per antenna port. Figure 2 , a time slot includes multiple orthogonal frequency division multiplexing (OFDM) symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. An OFDM symbol also refers to a symbol interval. Unless otherwise specified, an OFDM symbol may be referred to as a symbol. An RB includes 12 consecutive subcarriers in the frequency domain. Reference Figure 2 , the signal transmitted from each time slot can be composed of N size,μ grid,x *N RB sc subcarriers and N slot symb 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 Indicates the number of OFDM symbols in a time slot. RB sc is the number of subcarriers that constitute one RB and N RB sc = 12. The OFDM symbol may be called a cyclic shift OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol according to a multiple access scheme.

[0078] The number of OFDM symbols included in one slot may vary depending on the length of the cyclic prefix (CP). For example, in the case of a normal CP, one slot includes 14 OFDM symbols, but in the case of an extended CP, one slot may include 12 OFDM symbols. In certain embodiments, the extended CP may be used only at a 60 kHz subcarrier spacing. Figure 2 In the embodiment, for the convenience of description, one time slot is configured with 14 OFDM symbols as an example, but the embodiments of the present disclosure can be applied to time slots with different numbers of OFDM symbols in a similar manner. Figure 2 , each OFDM symbol includes N in the frequency domain size,μ grid,x *N RB scSubcarriers can be divided into data subcarriers for data transmission, reference signal subcarriers for reference signal transmission, and guard bands. The carrier frequency is also called the center frequency (fc).

[0079] An RB can be composed of N in the frequency domain RB sc For reference, a resource configured with one OFDM symbol and one subcarrier is referred to as a resource element (RE) or tone. Thus, one 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 a value from 0 to N in the frequency domain. size,μ grid,x *N RB sc –1 is the assigned index, and l can be from 0 to N in the time domain slot symb –1 The assigned index.

[0080] In order for a UE to receive signals from or transmit signals to a base station, the UE's time / frequency may be synchronized with the base station's time / frequency. This is because when the base station and UE are synchronized, the UE can determine the time and frequency parameters necessary to demodulate the downlink signal and transmit the uplink signal at the correct time.

[0081] Each symbol of a radio frame used in time division duplex (TDD) or unpaired spectrum may be configured with at least one of a DL symbol, a UL symbol, and a flexible symbol. A radio frame used as a DL carrier in frequency division duplex (FDD) or paired spectrum may be configured with a DL symbol or a flexible symbol, while a radio frame used as a UL carrier may be configured with a UL symbol or a flexible symbol. In a DL symbol, DL transmission is possible, but UL transmission is not possible. In a UL symbol, UL transmission is possible, but DL transmission is not possible. A flexible symbol may be determined to be used as DL or UL based on a signal.

[0082] Information on the type of each symbol, i.e., information indicating any one of DL symbols, UL symbols, and flexible symbols, may be configured with cell-specific or common radio resource control (RRC) signals. Additionally, information on the type of each symbol may be additionally configured with UE-specific or dedicated RRC signals. 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 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 from the last symbol of the slot immediately preceding the slot having only UL symbols. Here, a symbol not configured with any one of UL symbols and DL symbols is a flexible symbol.

[0083] When the information on 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 UL symbols and DL symbols is a flexible symbol.

[0084] The symbol type configured with the above RRC signals may be referred to as a semi-static DL / UL configuration. In the previously configured semi-static DL / UL configuration with RRC signals, 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 the physical DL control channel (PDCCH). In this case, a DL symbol or a UL symbol configured with the RRC signal does not change into another symbol type. Table 1 illustrates the dynamic SFI that the base station may indicate to the UE.

[0085] [Table 1]

[0086]

[0087] In Table 1, D represents a DL symbol, U represents a UL symbol, and X represents a flexible symbol. As shown in Table 1, a maximum of two DL / UL switchings may be allowed in one slot.

[0088] Figure 3 This diagram illustrates physical channels used in a 3GPP system (e.g., NR) and a typical signal transmission method using the physical channels.

[0089] If the UE is powered on or camped in a new cell, the UE performs an initial cell search (S101). Specifically, the UE can synchronize with the base station in the initial cell search. To this end, the UE can receive a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as a cell ID. Thereafter, the UE can receive a physical broadcast channel from the base station and obtain broadcast information in the cell.

[0090] When the initial cell search is completed, the UE receives the physical downlink shared channel (PDSCH) based on 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 article, the system information received by the UE is cell-common system information used for the UE to normally operate in the physical layer in the radio resource control (RRC) and is referred to as residual system information, or system information block (SIB) 1.

[0091] When the UE initially accesses the base station or does not have radio resources for signal transmission (i.e., the UE is in RRC_IDLE mode), the UE can perform a random access procedure on the base station (operations S103 to S106). First, the UE can send a preamble through the physical random access channel (PRACH) (S103) and receive a response message to 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 UE's identifier, etc. to the base station through the physical uplink shared channel (PUSCH) indicated by the UL grant sent from the base station through the PDCCH (S105). Next, the UE waits for the reception of the PDCCH as an indication of the base station for contention resolution. If the UE successfully receives the PDCCH using the UE's identifier (S106), the random access procedure is terminated. During the random access procedure, the UE can obtain UE-specific system information for normal operation of the UE in the physical layer in the RRC layer. When the UE obtains the UE-specific system information, the UE enters the RRC connected mode (RRC_CONNECTED mode).

[0092] The RRC layer is used to generate or manage messages for controlling the connection between the UE and the radio access network (RAN). More specifically, the base station and the UE can perform tasks such as broadcasting cell system information required for each UE in the cell, managing the delivery of paging messages, managing mobility and handover, UE measurement reporting and its control, UE capability management, and storage management in the RRC layer. Generally, since the update period of the signal delivered in the RRC layer is longer than the transmission time interval (TTI) in the physical layer, the RRC signal does not change and is maintained for a relatively long interval.

[0093] After the above process, the UE receives PDCCH / PDSCH (S107) and sends 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 PDCCH. DCI may include control information such as resource allocation information for the UE. In addition, the format of DCI may vary according to the intended use. The uplink control information (UCI) sent by the UE to the base station through UL includes DL / UL ACK / NACK signals, channel quality indicator (CQI), precoding matrix index (PMI), rank indicator (RI), etc. Here, CQI, PMI and RI may be included in 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 PUSCH and / or PUCCH.

[0094] Figure 4a and 4b The figure shows the SS / PBCH blocks used 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, it 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 To this end, the UE may 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 may obtain information such as a cell identity (ID).

[0095] refer to Figure 4a , the synchronization signal (SS) will be described in more detail. The synchronization signal can be classified into PSS and SSS. PSS can be used to obtain time domain synchronization and / or frequency domain synchronization, such as OFDM symbol synchronization and time slot synchronization. SSS can be used to obtain frame synchronization and cell group ID. 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 the 56th to 182nd subcarriers. Here, the lowest subcarrier index of the SS / PBCH block is numbered from 0. In the first OFDM symbol in which the PSS is transmitted, the base station does not transmit signals through the remaining subcarriers, i.e., the 0th to 55th subcarriers and the 183rd to 239th subcarriers. In addition, in the third OFDM symbol in which the SSS is transmitted, the base station does not transmit signals through the 48th to 55th subcarriers and the 183rd to 191st subcarriers. The base station transmits the physical broadcast channel (PBCH) through the remaining REs in the SS / PBCH block except for the above signals.

[0096] [Table 2]

[0097]

[0098] The SS allows a total of 1008 unique physical layer cell IDs to be grouped into 336 physical layer cell identifier groups, each group including three unique identifiers, through a combination of three PSSs and SSSs, specifically so that each physical layer cell ID will be part of only one physical layer cell identifier group. cell ID =3N (1) ID +N (2) ID The physical layer cell identifier group can be indicated by an index N ranging from 0 to 335. (1) ID and an index N ranging from 0 to 2 indicating a physical layer identifier in the physical layer cell identifier group (2) ID Uniquely defined. 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 of the PSS PSS (n) as follows.

[0099] d PSS (n) = 1-2x(m)

[0100] m=(n+43N (2) ID )mod 127

[0101] 0≤n<127

[0102] Here, x(i+7)=(x(i+4)+x(i)) mod 2 and is given as

[0103] [x(6)x(5)x(4)x(3)x(2)x(1)x(0)]=[1 1 1 0 1 1 0]

[0104] In addition, the sequence d of SSS SSS (n) as follows.

[0105] d SSS (n)=[1-2x0((n+m0)mod 127][1-2x i ((n+m1)mod 127]

[0106] m0=15floor(N (1) ID / 112)+5N (2) ID

[0107] m1=N (1) ID mod 112

[0108] 0≤n<127

[0109] Here, x0(i+7)=(x0(i+4)+x0(i))mod 2

[0110] x1(i+7)=(x1(i+1)+x1(i))mod 2 and is given as

[0111] [x0(6)x0(5)x0(4)x0(3)x0(2)x0(1)x0(0)]=[0 0 0 0 0 0 1]

[0112] [x1(6)x1(5)x1(4)x1(3)x1(2)x1(1)x1(0)]=[0 0 0 0 0 0 1]

[0113] A radio frame having a length of 10ms can be divided into two half-frames having a length of 5ms. Figure 4b, the time slot in which the SS / PBCH block is transmitted in each half-frame will be described. The time slot in which the SS / PBCH block is transmitted can be any 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. In addition, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n=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. In addition, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n=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. In addition, 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.

[0114] Figure 5a and 5b The diagram illustrates a process for transmitting control information and control channels in a 3GPP NR system. Figure 5a, the base station may add a cyclic redundancy check (CRC) masked (e.g., XORed) with a radio network temporary identifier (RNTI) to 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 RNTI used by one or more UEs can 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 RNTI may include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, the base station may perform rate matching according to the amount of resources used for PDCCH transmission after performing channel coding (e.g., polarity coding) (S204) (S206). Thereafter, the base station may multiplex 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. CCE is the basic resource unit for PDCCH, and one CCE may include multiple (e.g., six) resource element groups (REGs). One REG may be configured with multiple (e.g., 12) REs. The number of CCEs used for one PDCCH may be defined as an aggregation level. In a 3GPP NR system, aggregation levels of 1, 2, 4, 8, or 16 may be used. Figure 5b It is a diagram related to CCE aggregation levels and PDCCH multiplexing, and illustrates the types of CCE aggregation levels used for one PDCCH and CCEs transmitted in the control region accordingly.

[0115] Figure 6 Illustration of a control resource set (CORESET) in which a physical downlink control channel (PUCCH) can be transmitted in a 3GPP NR system.

[0116] A CORESET is a time-frequency resource in which a PDCCH (i.e., a control signal for a UE) is transmitted. In addition, a search space to be described later can be mapped to one CORESET. Therefore, instead of monitoring all frequency bands used for PDCCH reception, the UE can monitor the time-frequency domain designated as the CORESET and decode the PDCCH mapped to the CORESET. The base station can configure one or more CORESETs for each cell to the UE. A CORESET can be configured with up to three consecutive symbols on the time axis. In addition, a CORESET can be configured in units of six consecutive PRBs on the frequency axis. In the embodiment of Figure 5, CORESET#1 is configured with consecutive PRBs, while CORESET#2 and CORESET#3 are configured with discontinuous PRBs. A CORESET can be located in any symbol in a time slot. For example, in the embodiment of Figure 5, CORESET#1 starts at the first symbol of the time slot, CORESET#2 starts at the fifth symbol of the time slot, and CORESET#9 starts at the ninth symbol of the time slot.

[0117] Figure 7 Illustration of a method for setting a PUCCH search space in a 3GPP NR system.

[0118] In order to send the PDCCH to the UE, each CORESET may have at least one search space. In an embodiment of the present disclosure, the search space is a set of all time-frequency resources (hereinafter referred to as PDCCH candidates) that can be used to send the PDCCH of the UE. The search space may include a common search space that requires UEs of 3GPP NR to search together and a terminal-specific search space or a UE-specific search space that requires a specific UE to search. In the common search space, the UE may monitor the PDCCH that is set so that all UEs in the cell belonging to the same base station search together. In addition, a UE-specific search space may be set for each UE so that the UE monitors the PDCCH allocated to each UE at a search space position that is different according to the UE. In the case of a UE-specific search space, due to the limited control region to which the PDCCH can be allocated, the search space between the UEs may partially overlap and be allocated. Monitoring the PDCCH includes blind decoding the PDCCH candidates in the search space. When the blind decoding is successful, it can be expressed as (successfully) detecting / receiving the PDCCH, and when the blind decoding fails, it can be expressed as not detecting / not receiving or not successfully detecting / receiving the PDCCH.

[0119] For ease of explanation, a PDCCH that is scrambled with a group common (GC) RNTI previously known to one or more UEs in order to transmit DL 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 the RNTI of a specific terminal already known to a specific UE in order to transmit UL scheduling information or DL ​​scheduling information to a specific UE is referred to as a UE-specific PDCCH. The common PDCCH may be included in the common search space, and the UE-specific PDCCH may be included in the common search space or the UE-specific PDCCH.

[0120] The base station can signal each UE or UE group with information related to resource allocation of the paging channel (PCH) and downlink shared channel (DL-SCH) as transport channels (i.e., DL grant) or information related to resource allocation of the uplink shared channel (UL-SCH) and hybrid automatic repeat request (HARQ) (i.e., UL grant) through the PDCCH. The base station can transmit PCH transport blocks and DL-SCH transport blocks through the PDSCH. The base station can transmit data excluding specific control information or specific service data through the PDSCH. In addition, the UE can receive data excluding specific control information or specific service data through the PDSCH.

[0121] The base station can include information in the PDCCH about which UE (one or more UEs) the PDSCH data is to be sent and how the PDSCH data will be received and decoded by the corresponding UE, and send the PDCCH. For example, assume that the DCI sent on a specific PDCCH is CRC-masked with RNTI "A", and the DCI indicates that the PDSCH is allocated to radio resource "B" (e.g., frequency position) and indicates transmission format information "C" (e.g., transport block size, modulation scheme, coding information, etc.). The UE monitors the PDCCH using the RNTI information that the UE has. In this case, if there is a UE that performs blind decoding on the PDCCH using the "A" RNTI, the UE receives the PDCCH and receives the PDSCH indicated by "B" and "C" through the information of the received PDCCH.

[0122] Table 3 shows an embodiment of a physical uplink control channel (PUCCH) used in a wireless communication system.

[0123] [Table 3]

[0124] PUCCH format OFDM symbol length Number of bits 0 1-2 ≤2 1 4-14 ≤2 2 1-2 >2 3 4-14 >2 4 4-14 >2

[0125] The PUCCH may be used to transmit the following UL control information (UCI).

[0126] - Scheduling Request (SR): information for requesting UL UL-SCH resources.

[0127] -HARQ-ACK: A response to the PDCCH (indicating a DL SPS release) and / or a response to a DL transport block (TB) on the PDSCH. HARQ-ACK indicates whether the information sent on the PDCCH or PDSCH is received. The HARQ-ACK response includes a positive ACK (abbreviated as ACK), a negative ACK (hereinafter referred to as NACK), a 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 a bit value of 1, while NACK can be represented by a bit value of 0.

[0128] Channel State Information (CSI): Feedback information about the DL channel. The UE generates this information based on the CSI-Reference Signal (RS) transmitted by the base station. Multiple-Input Multiple-Output (MIMO)-related feedback information includes the Rank Indicator (RI) and the Precoding Matrix Indicator (PMI). The CSI can be divided into CSI Part 1 and CSI Part 2 based on the information indicated by the CSI.

[0129] In the 3GPP NR system, five PUCCH formats can be used to support various service scenarios, various channel environments and frame structures.

[0130] PUCCH format 0 is a format capable of delivering 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 can be transmitted through one or two OFDM symbols on the time axis and one PRB on the frequency axis. When PUCCH format 0 is transmitted in two OFDM symbols, the same sequence on the two symbols can be transmitted through different RBs. In this case, the sequence can be a sequence that is cyclically shifted (CS) from the basic sequence used in PUCCH format 0. Through this, the UE can obtain frequency diversity gain. In more detail, the UE can select the optimal frequency for each OFDM symbol according to the M bit Bit UCI(M bit =1 or 2) to determine the cyclic shift (CS) value m cs Alternatively, the CS value m can be determined based on the cs The cyclic shift sequence is mapped to 1 OFDM symbol and 12 REs of 1 RB to transmit a basic sequence of length 12. When the number of cyclic shifts available to the UE is 12 and M bit =1, the 1-bit UCI 0 and 1 can be mapped to two cyclic shift sequences with a cyclic shift value difference of 6. In addition, when M bit=2, the 2-bit UCI 00, 01, 11 and 10 can be mapped to four cyclic shift sequences with cyclic shift values ​​differing by 3 respectively.

[0131] PUCCH format 1 can deliver 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 can be transmitted through continuous 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, M bit =1 UCI is BPSK modulated. The UE can use quadrature phase shift keying (QPSK) to modulate M bit =2 for modulation. The signal is obtained by multiplying the modulated complex-valued symbol d(0) by a sequence of length 12. In this case, the sequence may be a base sequence for PUCCH format 0. The UE extends the even-numbered OFDM symbols to which PUCCH format 1 is allocated by 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) may be extended with the OCC and mapped to the odd-numbered OFDM symbols of PUCCH format 1.

[0132] PUCCH format 2 can deliver more than 2 bits of UCI. PUCCH format 2 can be sent through one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. When PUCCH format 2 is sent in two OFDM symbols, the sequences sent in different RBs of the two OFDM symbols can be the same as each other. Here, the sequence can be a plurality of modulated complex-valued symbols d(0), ..., d(M symbol -1). Here, M symbol It can be M bit / 2. Through this, the UE can obtain frequency diversity gain. More specifically, for M bit bits UCI (M bit >2) Bit-level scrambling, QPSK modulation, and mapping to RBs of one or two OFDM symbols. Here, the number of RBs can be one from 1 to 16.

[0133] PUCCH format 3 or PUCCH format 4 can deliver more than 2 bits of UCI. PUCCH format 3 or PUCCH format 4 can be transmitted through continuous 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 uses e / 2-binary phase shift keying (BPSK) or QPSK for M bit bits UCI (M bit >2) is modulated to generate complex-valued symbols d(0) to d(M symb -1). Here, when π / 2-BPSK is used, M symb =M bit , and when using QPSK, M symb =M bit / 2. The UE may not apply block-based extension to PUCCH format 3. However, the UE may apply block-based extension to one RB (i.e., 12 subcarriers) using a PreDFT-OCC length of 12, allowing PUCCH format 4 to 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.

[0134] 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 of the UCI transmitted by the UE and the maximum coding rate. When the UE uses PUCCH format 2, the UE can 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 can be used by PUCCH format 2, PUCCH format 3, or PUCCH format 4, the UE can transmit only the remaining UCI information without transmitting some UCI information according to the priority of the UCI information.

[0135] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured via RRC signaling to indicate frequency hopping within a time slot. When frequency hopping is configured, the index of the RB to be frequency hopped can be configured via RRC signaling. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted via N OFDM symbols on the time axis, the first hop can have floor (N / 2) OFDM symbols and the second hop can have ceiling (N / 2) OFDM symbols.

[0136] 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 in which the PUCCH is repeatedly transmitted can be configured through RRC signals. The repeatedly transmitted PUCCH must start at an OFDM symbol at a constant position in each time slot and have a constant length. When one of the OFDM symbols of the time slot in which the UE should transmit the PUCCH is indicated as a DL symbol through RRC signals, 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.

[0137] Meanwhile, in a 3GPP NR system, a 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 in accordance with TDD or in 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 in accordance with FDD or in paired spectrum can receive up to four DL BWPs on a DL carrier (or cell) and 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 may be referred to as an active BWP.

[0138] 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 the other configured BWPs are deactivated. In a carrier (or cell) operating in TDD, the base station can include a bandwidth part indicator (BPI) in the DCI used to schedule the PDSCH or PUSCH, indicating the BWP to be activated to change the UE's DL / UL BWP pair. The UE can receive the DCI used to schedule 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 used to schedule the PDSCH to change the UE's DL BWP. 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 used to schedule the PUSCH to change the UE's UL BWP.

[0139] Figure 8 is a conceptual diagram illustrating carrier aggregation.

[0140] Carrier aggregation is a method in which a UE uses multiple frequency blocks or (logically) cells configured with UL resources (or component carriers) and / or DL ​​resources (or component carriers) as a large logical frequency band, allowing the wireless communication system to use a wider frequency band. A component carrier may also be referred to as a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, hereinafter, for convenience of description, the term "component carrier" is used.

[0141] refer to Figure 8 As an example of a 3GPP NR system, the entire system band may include up to 16 component carriers, and each component carrier may have a bandwidth of up to 400 MHz. A component carrier may include one or more physically contiguous subcarriers. Figure 8 , each component carrier is shown to have the same bandwidth, but this is merely an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other on the frequency axis, the drawings are shown in a logical concept, and each component carrier may be physically adjacent to each other, or may be spaced apart.

[0142] A different center frequency can be used for each component carrier. Alternatively, a common center frequency can be used in physically adjacent component carriers. Figure 8 In the embodiment of FIG5 , all component carriers are physically adjacent, then center frequency A can be used in all component carriers. Alternatively, assuming that the respective component carriers are not physically adjacent to each other, center frequency A and center frequency B can be used in each component carrier.

[0143] When the total system frequency band is extended by carrier aggregation, the frequency band used to communicate with each UE can be defined in units of component carriers. UE A can use 100 MHz as the total system frequency band and use all five component carriers to perform communication. UEs B1 to B5 can use only 20 MHz bandwidth and use one component carrier to perform communication. UEs C1 and C2 can each use 40 MHz bandwidth and use two component carriers to perform communication. These two component carriers can be logically / physically adjacent or non-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.

[0144] Figure 9 It is a diagram for explaining signal carrier communication and multi-carrier communication. In particular, Figure 9 (a) shows a single carrier subframe structure and Figure 9 (b) shows a multi-carrier subframe structure.

[0145] refer to Figure 9(a), in FDD mode, a general wireless communication system can perform data transmission or reception through one DL frequency band and one UL frequency band corresponding thereto. In another specific embodiment, in TDD mode, a 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. Figure 9 (b) Three 20 MHz component carriers (CCs) can be aggregated into each of the UL and DL, enabling support of a 60 MHz bandwidth. Each CC may be adjacent or non-adjacent to each other in the frequency domain. Figure 9 (b) shows the case where the bandwidth of the UL CC and the bandwidth of the DL CC are the same and symmetrical, 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 CC assigned / configured to a specific UE through RRC can be called the serving DL / UL CC for the specific UE.

[0146] The base station can perform communication with the UE by activating some or all of the UE's serving CCs or deactivating some CCs. The base station can change the CCs to be activated / deactivated and change the number of CCs to be activated / deactivated. If the base station allocates 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 reconfigured or the UE is handed over. One CC that is not deactivated by the UE is called a primary CC (PCC) or primary cell (PCell), while a CC that the base station can freely activate / deactivate is called a secondary CC (SCC) or secondary cell (SCell).

[0147] At the same time, 3GPP NR uses the concept of cells to manage radio resources. A cell is defined as a combination of DL resources and UL resources, that is, a combination of DL CCs and UL CCs. A cell can be configured with DL resources alone or a combination of DL resources and UL resources. When carrier aggregation is supported, the link between the carrier frequency of the DL resources (or DL ​​CC) and the carrier frequency of the UL resources (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, while the cell corresponding to the SCC is called the SCell. The carrier corresponding to the PCell in the DL is the DL PCC, while 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, while 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 with only the PCell.

[0148] As described above, the term "cell" used in carrier aggregation is distinguished from the term "cell" which refers to a geographical area where communication services are provided by a base station or an antenna group. That is, a component carrier may also be referred to as a scheduling cell, a scheduled cell, a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, to distinguish between cells representing a geographical area and cells in carrier aggregation, in this disclosure, cells in carrier aggregation are referred to as CCs, and cells in a geographical area are referred to as cells.

[0149] Figure 10 is a diagram showing an example in which cross-carrier scheduling technology is applied. When cross-carrier scheduling is set, the control channel sent through the first CC can use the carrier indicator field (CIF) to schedule the data channel sent 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 sent 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 a scheduling cell, and a specific SCell can be designated as a scheduling cell by an upper layer.

[0150] exist Figure 10In the embodiment of the present invention, it is assumed that three DL CCs are merged. Here, it is assumed that DL component carrier #0 is DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are DL SCC (or SCell). In addition, it is assumed that DL PCC is set as the PDCCH monitoring CC. When cross-carrier scheduling is not configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is disabled, and each DL CC is able to send only the PDCCH for scheduling its PDSCH without CIF according to the NR PDCCH rule (non-cross-carrier scheduling, self-carrier scheduling). At the same time, if cross-carrier scheduling is configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is enabled, and a specific CC (e.g., DL PCC) can use 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, PDCCH is not sent in another DL CC. Therefore, the UE monitors the PDCCH not including 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.

[0151] on the other hand, Figure 9 and Figure 10 The subframe structure of the 3GPP LTE-A system is shown in the figure, and the same or similar configuration can be applied to the 3GPP NR system. However, in the 3GPP NR system, Figure 9 and Figure 10 The subframes can be replaced by time slots.

[0152] Figure 11 is a block diagram showing the configuration 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 may 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 (e.g., a macro cell, a femto cell, a pico cell, etc.) corresponding to a service area, and performs functions such as signal transmission, channel designation, channel monitoring, self-diagnosis, and relaying. The base station may be referred to as a next-generation node B (gNB) or an access point (AP).

[0153] As shown in the drawing, the 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 .

[0154] First, the processor 110 can execute various instructions or processes within the UE 100 and process data. In addition, the processor 110 can control the overall operation of each unit comprising the UE 100 and can control the transmission / reception of data between the units. Here, the processor 110 can be configured to perform operations according to the embodiments described in the present disclosure. For example, the processor 110 can receive time slot configuration information, determine a time slot configuration based on the time slot configuration information, and perform communication according to the determined time slot configuration.

[0155] 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 a plurality of network interface cards (NICs) such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123 in an internal or external form. In the drawings, the communication module 120 is shown as an integrally integrated module, but unlike the drawings, each network interface card can be independently arranged according to circuit configuration or usage.

[0156] The cellular communication interface card 121 can transmit or receive radio signals with 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 that uses a frequency band less than 6 GHz. The at least one NIC module of the cellular communication interface card 121 can independently perform cellular communication with at least one of the base station 200, an external device, and a server in a frequency band less than 6 GHz supported by the corresponding NIC module in accordance with a cellular communication standard or protocol.

[0157] The cellular communication interface card 122 can transmit or receive radio signals with 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 the 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 that uses a frequency band greater than 6 GHz. The at least one NIC module of the cellular communication interface card 122 can independently perform cellular communication with at least one of the base station 200, an external device, and a server in a frequency band greater than 6 GHz supported by the corresponding NIC module in accordance with a cellular communication standard or protocol.

[0158] Unlicensed band communication interface card 123 transmits or receives radio signals with at least one of base station 200, an external device, and a server using a third frequency band that is an unlicensed frequency band, and provides unlicensed band communication services based on instructions from processor 110. Unlicensed band communication interface card 123 may include at least one NIC module that uses an unlicensed frequency band. For example, the unlicensed frequency band may be a 2.4 GHz or 5 GHz frequency band. The at least one NIC module of unlicensed band communication interface card 123 may independently or dependently perform wireless communication with at least one of base station 200, an external device, and a server according to an unlicensed frequency band communication standard or protocol supported by the corresponding NIC module.

[0159] The memory 130 stores a control program and various data therefor used in the UE 100. Such a control program may include a prescribed program required to perform wireless communication with at least one of the base station 200, an external device, and a server.

[0160] Next, the user interface 140 includes various input / output means provided in the UE 100. In other words, the user interface 140 can use various input means to receive user input, and the processor 110 can control the UE 100 based on the received user input. In addition, the user interface 140 can use various output means to perform output based on instructions from the processor 110.

[0161] Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects such as content or a user interface executed by the processor 110 based on a control instruction from the processor 110.

[0162] 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 .

[0163] First, the processor 210 can execute various instructions or programs and process internal data of the base station 200. In addition, the processor 210 can 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 can be configured to perform operations according to the embodiments described in the present disclosure. For example, the processor 210 can signal a time slot configuration and perform communication according to the signaled time slot configuration.

[0164] 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 220 may include multiple network interface cards, such as cellular communication interface cards 221 and 222 and an unlicensed band communication interface card 223, in an internal or external form. In the drawings, the communication module 220 is shown as an integrally integrated module, but unlike the drawings, each network interface card can be independently arranged according to circuit configuration or usage.

[0165] The cellular communication interface card 221 can 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 frequency 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 that uses a frequency band less than 6 GHz. The at least one NIC module of the cellular communication interface card 221 can independently perform cellular communication with at least one of the base station 100, an external device, and a server in a frequency band less than 6 GHz supported by the corresponding NIC module in accordance with a cellular communication standard or protocol.

[0166] The cellular communication interface card 222 can 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 the second frequency 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 that uses a frequency band of 6 GHz or higher. The at least one NIC module of the cellular communication interface card 222 can independently perform cellular communication with at least one of the base station 100, an external device, and a server in accordance with a cellular communication standard or protocol in a frequency band of 6 GHz or higher supported by the corresponding NIC module.

[0167] Unlicensed band communication interface card 223 transmits or receives radio signals with at least one of base station 100, an external device, and a server using a third frequency band that is an unlicensed frequency band, and provides unlicensed band communication services based on instructions from processor 210. Unlicensed band communication interface card 223 may include at least one NIC module that uses an unlicensed frequency band. For example, the unlicensed frequency band may be a 2.4 GHz or 5 GHz frequency band. The at least one NIC module of unlicensed band communication interface card 223 may independently or dependently perform wireless communication with at least one of base station 100, an external device, and a server in accordance with an unlicensed frequency band communication standard or protocol supported by the corresponding NIC module.

[0168] Figure 111 is a block diagram illustrating 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. Therefore, the aforementioned elements of the device can be installed in a single chip or multiple chips according to the design of the device. In addition, part of the configuration of the UE 100, such as the user interface 140 and the display unit 150, can be selectively provided in the UE 100. In addition, the user interface 140 and the display unit 150 can be additionally provided in the base station 200 as necessary.

[0169] Meanwhile, regarding the configuration for delivering HARQ-ACK, the UE may send the HARQ-ACK bit 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 a downlink control channel (e.g., PDCCH) for the base station in order to schedule the PDSCH for the UE. When only 1 TB is scheduled, the UE should feed back a 1-bit HARQ-ACK bit for the corresponding TB. When 2 TBs are scheduled, the UE should feed back a 2-bit HARQ-ACK bit for each of the two TBs. There may be a definite order between the 2-bit HARQ-ACK bit and the 2 TBs to avoid misunderstanding between the base station and the UE. For reference, 1TB is sent when the multiple-input multiple-output (MIMO) transmission rank or layer is low, and 2TB is sent when the MIMO transmission rank or layer is high.

[0170] The component carrier described in the embodiments of the present invention may be used together with the term "cell." Although the embodiments of the present invention are described with emphasis 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 a subframe (or time slot) multiplexed by HARQ-ACK.

[0171] When the UE uses carrier aggregation in which multiple carriers are aggregated and transmitted, each component carrier may be configured with a different transmission scheme. That is, component carrier #0 may be configured with 1TB transmission, while component carrier #1 may be configured with 2TB transmission. When one of self-carrier scheduling or cross-carrier scheduling is configured for the UE, the UE should decode the PDCCH by monitoring the component carriers on which the UE should monitor the PDCCH according to the scheme set for the UE, and should collect the HARQ-ACK for the TBs sent through the PDSCH in each component carrier and send the HARQ-ACK 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 called the occurrence of discontinuous transmission (DTX)), and may only collect the HARQ-ACK for the component carriers for which decoding has been successful, while excluding the HARQ-ACK for some of the component carriers, and send the HARQ-ACK on the PUCCH (or PUSCH). In this case, misunderstandings may occur between the base station and the UE when interpreting the HARQ-ACK feedback.

[0172] 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).

[0173] Figure 12 This is a diagram about a process of generating a semi-static HARQ-ACK codebook according to an embodiment of the present invention.

[0174] As described above, the semi-static HARQ-ACK codebook indicates that the UE and the base station agree in advance 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 a DL association set (or PDSCH candidate set). An embodiment of the present invention relates to a method for determining a DL association set (or PDSCH candidate set) in a semi-static HARQ-ACK codebook.

[0175] 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 sent (or scheduled) and the time slot in which the PUCCH is sent. The fallback DCI (or DCI format 1_0) can take a value in {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 RRC signals. Second, the above information includes all possible K0 values ​​indicated to the UE and a combination of the PDSCH start symbol and length within a time slot. Here, the PDSCH start symbol and length are jointly encoded and indicated by the start and length indicator value (SLIV). Here, the K0 value indicates the difference between the time slot in which the PDCCH is sent and the time slot in which the PDSCH scheduled by the PDCCH is sent. Third, the above information includes semi-static DL / UL configuration information. Semi-static DL / UL configuration is configuration information of a time slot configured with a cell-specific RRC signal or a 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 which position in which time slot the PDCCH can be sent. 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 an RRC signal, and the same PDSCH is repeatedly transmitted in a time slot according to the configured value. 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 by time slot aggregation.

[0176] refer to Figure 12 As an embodiment of the present invention, when the UE is configured to receive by time slot aggregation, the step of 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 .

[0177] First, in the first step, the UE can target a K1 value (denoted as K 1,k ) and a K0 and SLIV value (K 0,l , SLIV l ) Confirm the following. If in time slot nK 1,k , time slot nK 1,k -1, ..., time slot nK 1,k -(N rep -1) in at least one time slot through SLIVl There is no UL symbol in the indicated symbol position and in time slot nK 1,k -(N rep -1)-K0 has a CORESET and search space for monitoring PDCCH, then it can be assumed that the search space is 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 assigned to (K 1,k ,K 0,l ,SLIV l ) cannot be transmitted, and the UE cannot include the PDSCH in the DL association set (or PDSCH candidate set). For example, when at least one UL symbol overlaps with a symbol allocated with a PDSCH symbol in all time slots, the PDSCH cannot be transmitted.

[0178] In the second step, the UE may confirm the combination of the DL association set (or PDSCH candidate set) that may be included in the first step, as denoted by (K 1,k ) of multiple K1 values ​​and multiple K0 and SLIV values ​​(K 0,l SLIV l ) related to the following content.

[0179] Here, for the 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 numbered as n=1, 2, . . .

[0180] If, for combination n that may be included in the DL association set (or PDSCH candidate set) in the first step, the PDSCH allocations of other combinations m=n+1,... overlap with the PDSCH allocation of combination n for at least one symbol in at least one time slot, then combination m is combined with combination n into one, and combination m is excluded. The above scheme can be performed sequentially for n=1, 2,...

[0181] Dynamic HARQ-ACK codebook (Type-2 HARQ-ACK codebook) is a scheme for detecting DTX based on the downlink assignment index (DAI). The PDCCH used to schedule 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.

[0182] refer to Figure 15 When a PDSCH is transmitted from a base station on component carriers #0, #1, #3, #4, #5, and #7 to a UE that can use up to eight component carriers in combination, the (counter DAI, total DAI) value of component carrier #0 is (0, 5), the (counter DAI, total DAI) value of component carrier #1 is (1, 5), the (counter DAI, total DAI) value of component carrier #3 is (2, 5), the (counter DAI, total DAI) value of component carrier #4 is (3, 5), the (counter DAI, total DAI) value of component carrier #5 is (4, 5), and the (counter DAI, total DAI) value of component carrier #1 is (5, 5). When the UE fails to decode the PDCCH corresponding to component carrier #3, the UE can identify a PDSCH reception failure 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 recognize that a PDSCH has been scheduled after component carrier #5 but failed to be received through the counter DAI value and the total DAI value of the PDCCH corresponding to component carrier #5.

[0183] The problem to be solved by the present invention is to provide a method for sending a PUCCH including at least two pieces of HARQ-ACK information in one time slot. This operation is necessary to quickly receive retransmissions from the base station by sending 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, only a PUCCH including a maximum of one piece of HARQ-ACK information can be sent in one time slot. Therefore, the UE should send HARQ-ACK responses of different PDSCHs in different time slots or should multiplex the HARQ-ACK responses in one PUCCH to send the HARQ-ACK response. As mentioned above, in order to reduce latency, it is not appropriate to send HARQ-ACK in different time slots, and when sending by multiplexing with the same PUCCH, PUCCH coverage problems, that is, reliability problems, may occur. Therefore, a method for sending a PUCCH including multiple pieces of HARQ-ACK information in one time slot is being discussed in 3GPP NR Release 16. The present invention discloses this method.

[0184] 1.PDSCH group indicator

[0185] The UE may receive an indication of information about the group indicator (or group ID) of the PDSCH on the PDCCH (or DCI) that schedules the PDSCH, or may infer the information from a value composed of RRC or the value of another field sent on the DCI. The specific indication and inference methods will be described later. For convenience, the above indicator is referred to as the PDSCH group indicator. The UE can generate a HARQ-ACK codebook by multiplexing the HARQ-ACK of the PDSCH indicated by the same PDSCH group indicator, and can then always send it on the same PUCCH. That is, if different PDSCH group indicators are used, different PUCCHs can be sent in one time slot.

[0186] Figure 13 is a diagram illustrating a method for transmitting a PUCCH according to a PDSCH group indicator according to an embodiment of the present invention.

[0187] refer to Figure 13 , the PDSCH group indicator can have two values, i.e., 0 or 1, and in this case, at most two different PUCCHs can be transmitted in one slot. Figure 13 In an embodiment of the present invention, the PUCCH for transmitting the HARQ-ACK 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) of the two PDSCHs with the PDSCH group indicator value of 0. Figure 13 In an embodiment of the present invention, a PUCCH for transmitting HARQ-ACK for two PDSCHs having a PDSCH group indicator value of 1 may be determined based on a PUCCH resource indicator (PRI) indicated by a later-scheduled PDCCH (or DCI) among the two PDSCHs having a 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.

[0188] In order to transmit X PUCCHs in one slot, the PUCCH group indicator should indicate a value among 0, 1, ..., X-1. Therefore, B = ceil (log2 (X)) bits are required. These B bits can be explicitly indicated by the PDCCH (or DCI) or can be determined based on other factors. The implicit determination scheme can be similar to the scheme for implicitly determining the HARQ-ACK multiplexing indicator value, as described below.

[0189] When a PDSCH group indicator is used to be configured so that multiple PUCCHs are sent 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 sent on the PUCCH corresponding to the corresponding PDSCH group indicator. If the semi-static HARQ-ACK codebook corresponding to each PDSCH group indicator is generated independently without additional definition, each PUCCH sends a semi-static HARQ-ACK codebook of the same size in the same time slot, and therefore the coverage of the uplink PUCCH is limited. Therefore, the present invention proposes the following content for a method for reducing the size of a semi-static HARQ-ACK codebook sent on PUCCHs corresponding to different PDSCH group indicators in one time slot.

[0190] - As a first method, the UE may divide the time slot into two halves and may include PDSCH candidates that may be transmitted in the first half in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and may include PDSCH candidates that may be transmitted in the second half in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1. In other words, by using the time domain information occupied by the PDSCH candidates, it is possible to determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the PDSCH is to be included.

[0191] -As a second method, the UE may determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the HARQ-ACK of the PDSCH is to be included based on the K1 value indicated by the PDCCH (or DCI). For example, the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0 may include the HARQ-ACK of the PDSCH indicated by the four smaller K1 values ​​among the eight K1 values, 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.

[0192] -As a third method, the UE may determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the HARQ-ACK of the PDSCH is to be included based on 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 may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and the HARQ-ACK of at least 7 PDSCHs may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0.

[0193] -As a fourth method, the UE may determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the HARQ-ACK of the PDSCH is to be included, based on 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 may 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 may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1.

[0194] -As a fifth method, the UE may determine which PDSCH_group_indicator corresponds to the semi-static HARQ-ACK codebook in which the HARQ-ACK of the PDSCH is to be included based on the index of the time domain resource allocation field indicated by the PDCCH (or DCI). For example, the HARQ-ACK of the PDSCH with indication indexes 0 to 7 (bits 0000 to 0111) may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and the HARQ-ACK of the PDSCH with indication indexes 8 to 15 (bits 1000 to 1111) may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1.

[0195] -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 may configure the number of HARQ-ACK (or PDSCH) required for each time slot. For example, when two HARQ-ACK bits are configured per time slot, the UE may generate a semi-static HARQ-ACK codebook in which each time slot includes a maximum of 2 bits when generating the semi-static HARQ-ACK codebook for the 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-ACK (or PDSCH) required for each time slot may be configured as different values ​​in the semi-static HARQ-ACK codebook corresponding to different PDSCH_group_indicators.

[0196] As another method, the UE may configure a HARQ-ACK codebook for a specific PDSCH_group_indicator in a semi-static HARQ-ACK codebook scheme, and may configure a HARQ-ACK codebook for another specific PDSCH_group_indicator in a dynamic HARQ-ACK codebook scheme.

[0197] As another method, when the UE receives only one PDSCH with a specific PDSCH group indicator value (ie, when there is no HARQ-ACK for another PDSCH to be multiplexed), the UE may transmit only HARQ-ACK for the received one PDSCH on the PUCCH.

[0198] -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), when the number of PDSCH group indicators is four (0, 1, 2, 3), the base station may receive a value of 0, 1, 2, or 3 as the PDSCH group indicator value when receiving the configuration and PRI value for each PUCCH. That is, a PDSCH group indicator value of 0 may be configured for PRI values ​​of 0, 1, 2, and 3, a PDSCH group indicator value of 1 may be configured for PRI values ​​of 4, 5, 6, and 7, a PDSCH group indicator value of 2 may be configured for PRI values ​​of 8, 9, 10, and 11, and a PDSCH group indicator value of 3 may be configured for PRI values ​​of 12, 13, 14, and 16. The UE may identify the PDSCH group indicator value by the PRI value of the DCI that schedules the PDSCH. In the above embodiment, when the PRI value of the DCI is 10, the UE may recognize 2 as the PDSCH group indicator value.

[0199] Another problem to be solved by the present invention relates to a scheme for transmitting a PUCCH when PUCCH resources indicated by different PDSCH group indicators overlap.

[0200] Figure 14 is a diagram illustrating a case where a collision occurs when a PUCCH is transmitted according to a PDSCH group indicator according to an embodiment of the present invention.

[0201] refer to Figure 14 When the PUCCH resources corresponding to PDSCH group indicator 0 of a UE overlap with the PUCCH resources corresponding to PDSCH group indicator 1, the UE cannot send both PUCCHs simultaneously. Here, the UE can drop one of the two PUCCHs and send the other, or can send the HARQ-ACK codebooks for both PUCCHs on one PUCCH. The present invention specifically proposes the above operation.

[0202] In an operation of dropping one of two PUCCHs and transmitting the other PUCCH, which PUCCH should be transmitted is determined as follows.

[0203] - As a first embodiment, the UE transmits a PUCCH corresponding to a PDSCH_group_indicator indicated by the most recently received PDCCH (or DCI), and discards and does not transmit a PUCCH corresponding to a PDSCH_group_indicator for which this is not the case.

[0204] As a second embodiment, the PUCCH with the lower code rate value (higher reliability) among the two overlapping PUCCHs is transmitted, and the PUCCH for which this is not the case is discarded and not transmitted.

[0205] As a third embodiment, the PUCCH of the preceding resource among two overlapping PUCCHs is transmitted, and the PUCCH of the succeeding resource is discarded and not transmitted. Determining whether a resource is preceding or succeeding can be based on the last symbol of the resource. If the resources have the same last symbol, the resource with the preceding starting symbol can be determined as the preceding resource.

[0206] As a fourth embodiment, the PUCCH occupying longer symbols among two overlapping PUCCHs may be transmitted, and the PUCCH occupying smaller symbols may be discarded and not transmitted.

[0207] - As another embodiment, a PUCCH having a smaller PUCCH resource indicator (PRI) value among two overlapping PUCCHs may be transmitted, and a PUCCH having a larger value may be discarded.

[0208] In an operation of transmitting the HARQ-ACK codebook of two PUCCHs on one PUCCH, the HARQ-ACK codebook may be prepared as follows.

[0209] As a first embodiment, the UE may generate a large codebook by continuously concatenating HARQ-ACK codebooks according to the order of PDSCH_group_indicator values, and may transmit the codebook on one PUCCH resource.

[0210] -As a second embodiment, the UE may newly generate a codebook for the PDSCH candidates included in the overlapping PUCCH (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates), and may transmit the HARQ-ACK codebook on one PUCCH resource. Alternatively, when a large codebook is generated by continuously concatenating HARQ-ACK codebooks according to the order of PDSCH_group_indicator values, the UE may exclude HARQ-ACK bits included in the previous codebook from the subsequent HARQ-ACK codebook. The advantage of the second embodiment is that when HARQ-ACK bits for one PDSCH candidate exist in both overlapping PUCCHs in the first embodiment, these bits are not repeatedly transmitted.

[0211] A PDSCH group indicator with 1 bit may be included in the DCI that schedules the PDSCH, and if the PDSCH is included in a PDSCH group different from the PDSCH group sent previously, the 1 bit may be switched. When the value of the PDSCH group indicator is switched, the UE may determine that the PDSCH is included in the new PDSCH group. That is, the PDSCH may not be multiplexed with the HARQ-ACK of the previous PDSCH group, but may be multiplexed with the HARQ-ACK of the new PDSCH group. When the value of the PDSCH group indicator is not switched, the UE may determine that the PDSCH is included in the previous PDSCH group. That is, the PDSCH may be multiplexed with the HARQ-ACK of the previous PDSCH group.

[0212] 2. Finer K1 granularity

[0213] The PDCCH (or DCI) that schedules the PDSCH may 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 transmitted. Since the unit of the K1 value is a time slot, two or more PUCCHs cannot be transmitted in one time slot. The unit (or granularity) of the K1 value indicated by the DCI may be determined to be smaller than the unit of the time slot so that a PUCCH including one or more HARQ-ACKs can be transmitted in one time slot.

[0214] Figure 15 is a diagram illustrating a method for transmitting a PUCCH when a unit of K1 is set to a half slot according to an embodiment of the present invention.

[0215] refer to Figure 15 , the unit of K1 can be determined as half a slot. That is, the K1 value is the number of half slots between the half slot in which the scheduled PDSCH ends and the half slot in which the PUCCH on which the HARQ-ACK is transmitted is transmitted.

[0216] When the granularity of K1 is given as a sub-time slot (or symbol set), the K1 value indicates the number of sub-time slots between the sub-time slot in which the last symbol of PDSCH is included and the sub-time slot in which the first symbol of PUCCH is included. That is, if the K1 value is 0, the value indicates that the sub-time slot in which the last symbol of PDSCH is included and the sub-time slot in which the first symbol of PUCCH is included are the same sub-time slot. As another embodiment, when the granularity of K1 is given as a sub-time slot (or symbol set), the K1 value indicates the number of sub-time slots between the last sub-time slot of the time slot in which the last symbol of PDSCH is included and the sub-time slot in which the first symbol of PUCCH is included. That is, if the K1 value is 0, the value indicates that the last sub-time slot of the time slot in which the last symbol of PDSCH is included and the sub-time slot in which the first symbol of PUCCH is included are the same sub-time slot. As another embodiment, when the granularity of K1 is given as a sub-time slot (or symbol set), the K1 value indicates the number of sub-time slots between the last sub-time slot of the time slot in which the last symbol of PDSCH is included and the sub-time slot in which the first symbol of PUCCH is included. proc,1 The number of subslots between the first subslot among the subslots after time and the subslot in which the first symbol of the PUCCH is included. Here, T proc,1 Indicates the minimum time it takes to receive a PDSCH and send a valid HARQ-ACK. This value is specified in TS 38.214.

[0217] Another problem to be solved by the present invention relates to a scheme for transmitting a PUCCH when PUCCH resources indicated by different half-slots (or K1 units) overlap in one slot.

[0218] Figure 16 is a diagram illustrating a case where a collision occurs when a PUCCH is transmitted when the unit of K1 is set to a half slot according to an embodiment of the present invention.

[0219] refer to Figure 16 When a UE's PUCCH resources starting in the first half of a time slot overlap with those starting in the second half of a time slot, the UE cannot send both PUCCHs simultaneously. Here, the UE can drop one of the two PUCCHs and send the other, or it can send the HARQ-ACK codebooks for both PUCCHs on one PUCCH. The embodiments of the present invention specifically propose the above operations.

[0220] In an operation of dropping one of two PUCCHs and transmitting the other PUCCH, which PUCCH should be transmitted is determined as follows.

[0221] - 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.

[0222] As a second embodiment, the PUCCH with the lower code rate value (higher reliability) among the two overlapping PUCCHs is transmitted, and the PUCCH for which this is not the case is discarded and not transmitted.

[0223] As a third embodiment, the PUCCH of the preceding resource among two overlapping PUCCHs is transmitted, and the PUCCH of the succeeding resource is discarded and not transmitted. Determining whether a resource is preceding or succeeding may be based on the last symbol of the resource. If the resources have the same last symbol, the resource with the preceding starting symbol may be determined as the preceding resource.

[0224] As a fourth embodiment, the PUCCH occupying longer symbols among two overlapping PUCCHs may be transmitted, and the PUCCH occupying smaller symbols may be discarded and not transmitted.

[0225] - As another embodiment, a PUCCH having a smaller PUCCH resource indicator (PRI) value among two overlapping PUCCHs may be transmitted, and a PUCCH having a larger value may be discarded.

[0226] In an operation of transmitting the HARQ-ACK codebook of two PUCCHs on one PUCCH, the HARQ-ACK codebook may be prepared as follows.

[0227] As a first embodiment, the UE may generate a large codebook by sequentially concatenating HARQ-ACK codebooks in chronological order (i.e., the HARQ-ACK codebook instructed to be sent using the first half of the time slot is located before the HARQ-ACK codebook instructed to be sent using the second half of the time slot), and may transmit the codebook on one PUCCH resource.

[0228] -As a second embodiment, the UE may newly generate a codebook for the PDSCH candidates included in the overlapping PUCCH (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates), and may transmit the HARQ-ACK codebook on one PUCCH resource. Alternatively, when a large codebook is generated by sequentially concatenating HARQ-ACK codebooks in chronological order, the UE may exclude HARQ-ACK bits included in the previous codebook from the subsequent HARQ-ACK codebook. The advantage of the second embodiment is that when HARQ-ACK bits for one PDSCH candidate exist in both overlapping PUCCHs in the first embodiment, these bits are not repeatedly transmitted.

[0229] 3.HARQ-ACK multiplexing indicator

[0230] As one embodiment of the present invention, the UE may receive an indication of information about whether the HARQ-ACK of the PDSCH is multiplexed with other HARQ-ACKs from the PDCCH (or DCI) that schedules the PDSCH. For convenience, the above indicator is referred to as a HARQ-ACK multiplexing indicator. The HARQ-ACK multiplexing indicator can 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 in order to be sent, and 1 indicates that the HARQ-ACK of the PDSCH is multiplexed with the HARQ-ACK of another PDSCH in order to be sent. Here, not being multiplexed with the HARQ-ACK of another PDSCH in order to be sent means that the PUCCH sent by including the HARQ-ACK of the PDSCH does not include the HARQ-ACK information of another PDSCH. Therefore, when the PUCCH is configured to transmit 1 bit (or 2 transmission blocks of the PDSCH), the PUCCH includes a 2-bit HARQ-ACK, and the HARQ-ACK can be transmitted in one of PUCCH formats 0 and PUCCH format 1 according to the bit size. Multiplexing with the HARQ-ACK of another PDSCH to be transmitted indicates that the PUCCH transmitted by including the HARQ-ACK of the PDSCH may include HARQ-ACK information of another PDSCH. When multiplexing with the HARQ-ACK of another PDSCH to be transmitted, the HARQ-ACK codebook is generated using a dynamic HARQ-ACK codebook or a semi-static HARQ-ACK codebook scheme, and the HARQ-ACK codebook is transmitted on the PUCCH.

[0231] Figure 17 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.

[0232] refer to Figure 17, the UE sends the HARQ-ACK information of two PDSCHs with a HARQ-ACK multiplexing indicator value of 1 through one 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 resource of the PDSCH with a HARQ-ACK multiplexing indicator value of 0 is indicated by the PRI value of the scheduling PDSCH. Here, when the PUCCHs for sending HARQ-ACKs of different PDSCHs with a HARQ-ACK multiplexing indicator value of 0 (which is impossible with the multiplexing indicator of 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 to be sent. As another approach, the HARQ-ACK of a later scheduled PDSCH (i.e., when the PDCCH scheduling the PDSCH starts later or ends later) may be prioritized so that the PUCCH of the PDSCH is sent, and another overlapping PUCCH may not be sent. As another approach, the UE may not expect that two PUCCHs will overlap in one symbol.

[0233] As another embodiment of the present invention, HARQ-ACK multiplexing may be partially possible even when 0 is indicated as the HARQ-ACK multiplexing indicator value (HARQ-ACK multiplexing with another PDSCH is not possible). For example, if two PDSCHs for which 0 is indicated as the HARQ-ACK multiplexing indicator value are indicated to be transmitted 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 may be multiplexed and transmitted. Here, the HARQ-ACK bits of the later scheduled PDSCH are located after the HARQ-ACK bits of the earlier scheduled PDSCH.

[0234] Figure 18 is a diagram illustrating a HARQ-ACK multiplexing method using a PRI when a PUCCH is transmitted according to a HARQ-ACK multiplexing indicator according to an embodiment of the present invention.

[0235] refer to Figure 18 (a), when PDSCHs for which 0 is indicated as the HARQ-ACK multiplexing indicator value have the same PRI value i, the UE may transmit HARQ-ACK for two PDSCHs on a PUCCH resource corresponding to PRI=i.

[0236] refer to Figure 18(b) , when the PDSCH for which 0 is indicated as the HARQ-ACK multiplexing indicator value has different PRI values, the UE may transmit each HARQ-ACK information on a PUCCH resource corresponding to the corresponding PRI value.

[0237] The PUCCH resources for transmitting HARQ-ACK for a PDSCH with a HARQ-ACK multiplexing indicator value of 1 and the PUCCH resources for transmitting HARQ-ACK for a PDSCH with a HARQ-ACK multiplexing indicator value of 0 may overlap. As a PUCCH transmission method for this situation, according to an embodiment of the present invention, the UE may always prioritize and transmit the PUCCH for transmitting HARQ-ACK for a PDSCH with a HARQ-ACK multiplexing indicator value of 0, and may discard the PUCCH for transmitting HARQ-ACK for a PDSCH with a HARQ-ACK multiplexing indicator value of 1. As another embodiment, if the last symbol of the PUCCH used to send HARQ-ACK for the PDSCH with the HARQ-ACK multiplexing indicator value of 1 ends before or at the same time as the last symbol of the PUCCH used to send HARQ-ACK for the PDSCH with the HARQ-ACK multiplexing indicator value of 0, the UE can append the HARQ-ACK bits of the PDSCH with the HARQ-ACK multiplexing indicator value of 0 to the HARQ-ACK of the PDSCH with the HARQ-ACK multiplexing indicator value of 1 and send it on the PUCCH resources of the PDSCH with the HARQ-ACK multiplexing indicator value of 1.

[0238] Although the HARQ-ACK multiplexing indicator is represented by 1 bit for convenience, the indicator may be implicitly indicated as follows.

[0239] -As a first method, the HARQ-ACK multiplexing indicator may be determined according to the RNTI. For example, if the PDCCH (or DCI) that schedules 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 HARQ-ACK information of another PDSCH is possible), and, when the PDCCH (or DCI) that schedules the PDSCH is scrambled with a specific RNTI (e.g., an RNTI for a 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 HARQ-ACK of another PDSCH is not possible).

[0240] -As a second method, the HARQ-ACK multiplexing indicator can be determined based on 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, in general, the PDSCH of the URLLC service needs to quickly indicate the 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 as a time slot unit (e.g., 1 time slot or 2 time slots) or an absolute time unit (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 the value. That is, when the UE receives an indication of the value, the UE can only send the HARQ-ACK for one PDSCH without generating a codebook.

[0241] -As a third method, the HARQ-ACK multiplexing indicator can be determined based on the modulation and coding scheme (MCS) value. Here, the MCS value indicates the code rate of the scheduled PDSCH. Generally speaking, the PDSCH used for 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. For another example, the HARQ-ACK multiplexing indicator can be determined based on 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.

[0242] As a fourth method, the HARQ-ACK multiplexing indicator may be determined to be 1 using a combination of specific values ​​of other fields transmitted on the DCI.

[0243] -As a fifth method, the HARQ-ACK multiplexing indicator can be determined based on the search space (or CORESET) in which the PDCCH (or DCI) has been detected. For example, the base station can additionally indicate the search space (or CORESET) used for URLLC transmission to the UE. When the PDCCH (or DCI) is received in the above-mentioned search space (or CORESET), the UE can determine that the HARQ-ACK multiplexing indicator is 0. When the PDCCH (or DCI) is received in another search space (or CORESET), the UE can determine the HARQ-ACK multiplexing indicator to be 1. As another method, the UE can distinguish the search space (or CORESET) 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) used for URLLC transmission. As an embodiment, the specific period can be 1 time slot.

[0244] As a sixth method, the UE may determine the HARQ-ACK multiplexing indicator value based on the control channel element (CCE) aggregation level of the received PDCCH. For example, if the CCE aggregation level exceeds a specific value, the UE may determine that the HARQ-ACK multiplexing indicator of the PDCCH is 0. Here, the specific CCE aggregation level value may be determined to be 8 or 16.

[0245] -As a seventh method, the HARQ-ACK multiplexing indicator value may be determined by the DCI format (or DCI length). For example, if compact DCI is configured for the UE, the UE may determine that the HARQ-ACK multiplexing indicator value of the PDSCH scheduled by the compact DCI is 0. Here, the compact DCI, which is the DCI format for scheduling the URLLC PDSCH, has a smaller payload size than the payload size of the fallback DCI (DCI format 0_0 / 1_0).

[0246] 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 is used among the PUCCH resources configured by the base station for the UE. When the UE receives an indication of a specific value among the PRI values, the UE can determine the HARQ-ACK multiplexing indicator value to be 0. This is because all configured PUCCH resources are not suitable for sending URLLC HARQ-ACK. For example, since PUCCH resources with more than 2 bits among the PUCCH resources are not suitable for sending URLLC HARQ-ACK, for the PRI indicating the corresponding PUCCH resources, the UE can determine the HARQ-ACK multiplexing indicator value to be 1.

[0247] As a ninth method, the HARQ-ACK multiplexing indicator value may be determined by the HARQ process number. For example, when a specific value among the HARQ process numbers is indicated, the UE may determine the HARQ-ACK multiplexing indicator value to be 1 and transmit HARQ-ACK for only one PDSCH.

[0248] 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 allow HARQ-ACK to be transmitted 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 to be 1 and transmit HARQ-ACK only for one PDSCH.

[0249] Another embodiment of the present invention relates to a method for a UE to interpret a K1 value.

[0250] 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 transmitted is transmitted (wherein the time slot may be replaced by a specific unit smaller than the time slot). However, processing time may occur when the UE actually receives and decodes the PDSCH and generates the PUCCH for transmitting the HARQ-ACK. Therefore, it is not possible to indicate a specific K1 value, such as 0. The problem to be solved by the present invention is to define the value of K1, except for the value that cannot be indicated.

[0251] - As a first embodiment of the present invention, when determining the K1 value, the UE may exclude the time period from the last symbol of the PDSCH to the PDSCH processing time T proc,1 (Value defined in TS 38.214). That is, when the above-mentioned time slot is called an invalid time slot, the K1 value can be defined as the number of time slots excluding the invalid time slot 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 transmitted.

[0252] -As a second embodiment of the present invention, the UE cannot transmit the corresponding PUCCH on the semi-static DL symbol configured from the higher layer. Therefore, the UE may exclude the time slot configured with only the semi-static DL symbol when determining the K1 value. Alternatively, the UE may exclude the time slot in which it is impossible to transmit all PUCCHs due to the semi-static DL symbol when determining the K1 value. That is, when the time slot in which the PUCCH resource indicated by the PRI and the semi-static DL symbol overlap and thus the PUCCH cannot be transmitted is called an invalid time slot, the UE may define the K1 value as the number of time slots excluding the invalid time slot 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 transmitted.

[0253] The K1 or PRI field may not be configured to reduce the DCI overhead (DCI payload size) in the PDCCH (or DCI) scheduling URLLC. An embodiment of the present invention describes a method for determining PUCCH resources when the K1 or PRI field is not configured.

[0254] - 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 a time slot in which transmission of the next PUCCH (indicated by the PRI) is possible, except for the PDSCH processing time T starting from the last symbol of the PDSCH. proc,1 (values ​​defined in TS 38.214) outside the time slots that are fully included during the

[0255] 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 a time slot in which the symbol indicated by the PRI and the semi-static DL symbol do not overlap.

[0256] As a third embodiment of the present invention, when the PRI field is not configured, the PUCCH resource may be the earliest ending PUCCH resource among the PUCCH resources configured in the time slot indicated by K1.

[0257] -As a fourth embodiment of the present invention, when the PRI field is not configured, the PUCCH resource may be the earliest ending PUCCH resource among the PUCCH resources in the time slot indicated by K1, except that the PDSCH processing time T is not satisfied. proc,1 Here, PUCCH resources overlapping with semi-static DL symbols may be excluded.

[0258] Figure 19is a diagram illustrating a method for transmitting a PUCCH when K1 and PRI fields do not exist according to an embodiment of the present invention.

[0259] refer to Figure 19 , when both K1 and PRI fields are not configured in PDCCH (or DCI), the UE determines the PUCCH resources by the following method. Figure 19 In the embodiment, a total of four PUCCH resources are configured. PUCCH resource #1 does not meet the processing time requirement and can be excluded. Among the remaining PUCCH resources #2, #3, and #4, the earliest ending PUCCH resource is #3. Therefore, the UE can determine that #3 is the PUCCH resource for HARQ-ACK.

[0260] Another problem to be solved by the present invention relates to a design method for 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 in order to increase the probability of successful PDCCH reception of the UE. Here, the term "omitted" means configuring it to 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 bit 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 so that these bits are sent using the HARQ-ACK codebook. However, since the counter DAI field is omitted, a method for determining the order of HARQ-ACK bits in the HARQ-ACK codebook is needed.

[0261] As a first embodiment of the present invention, the UE may determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook based on the reception time information of the PDCCH that schedules the PDSCH. In more detail, when the starting symbol of the CORESET or search space including the PDCCH that schedules the first PDSCH precedes the starting symbol of the CORESET or search space including the PDCCH that schedules the second PDSCH, the HARQ-ACK bit of the first PDSCH is located before the HARQ-ACK bit of the second PDSCH in the HARQ-ACK codebook. If the starting symbols of the CORESET or search space are the same, the HARQ-ACK bit is located before the HARQ-ACK bit of the PDSCH scheduled by the PDCCH with the last symbol of the preceding CORESET or search space.

[0262] As a second embodiment of the present invention, the UE can determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook based on the time information of the PDSCH. In more detail, when the starting symbol of the first PDSCH is before the starting symbol of the second PDSCH, the HARQ-ACK bit of the first PDSCH is located before the HARQ-ACK bit 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 that schedules the PDSCH. If the starting symbols of the PDSCH are the same, the HARQ-ACK bit of the PDSCH with the last symbol of the preceding PDSCH is arranged at 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.

[0263] As a third embodiment of the present invention, the UE may determine the order of the HARQ-ACK bits in the HARQ-ACK codebook based on the HARQ process ID (or HARQ process number) of the PDCCH that schedules the PDSCH. In more detail, when the HARQ process ID of the first PDSCH is referred to as A in the PDCCH that schedules the first PDSCH, and the HARQ process ID of the second PDSCH is referred to as B in the PDCCH that schedules the second PDSCH, the HARQ-ACK bit of the PDSCH with the smaller value between A and B may be located before the HARQ-ACK bit of the PDSCH with the larger value in the HARQ-ACK codebook. That is, the position of the HARQ-ACK bit may 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 using one HARQ-ACK codebook have different values. That is, the UE does not expect to generate HARQ-ACK bits for PDSCHs with the same HARQ process ID in one HARQ-ACK codebook.

[0264] As a fourth embodiment of the present invention, the UE may use information of the cell from which the PDCCH scheduling the PDSCH is received 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 index of the cell from which the PDCCH scheduling the PDSCH is received.

[0265] As a fourth embodiment of the present invention, the UE may determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook using information of the CORESET (or search space) from which the PDCCH scheduling the PDSCH is received. Here, the information of the CORESET (or search space) may be an 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 PDSCHs received from different CORESETs (or search spaces) in the HARQ-ACK codebook according to the ascending order of the index of the CORESET (or search space) from which the PDCCH scheduling the PDSCH is received.

[0266] 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 a 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 process of the UE. According to TS 38.211, point A is as follows.

[0267] - offsetToPointA for PCell downlink, where offsetToPointA represents the frequency offset between point A and the lowest subcarrier of the lowest resource block, with the subcarrier spacing provided by the higher-layer parameter subCarrierSpacingCommon and overlapping with the SS / PBCH block used by the UE for initial cell selection, expressed in resource blocks, assuming a subcarrier spacing of 15 kHz for FR1 and 60 kHz for FR2;

[0268] -absoluteFrequencyPointA, for all other cases, where absoluteFrequencyPointA represents the frequency position of point A, as expressed in ARFCN.

[0269] The UE may be configured to monitor multiple PDCCHs. In this case, the UE may receive different PDCCHs in different frequency domains. Here, the UE may arrange the HARQ-ACK bits of the PDSCHs received in different frequency domains in the HARQ-ACK codebook according to the ascending order of the lowest PRB index of the PDCCH that schedules 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 may be determined in the HARQ-ACK codebook.

[0270] The first to sixth embodiments described above can be combined to determine the order of 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 HARQ-ACK bits can be first determined in the HARQ-ACK codebook based on the time domain information of the PDCCH, and when the order cannot be determined based on the time domain information, the order can be determined based on the HARQ process ID according to the third embodiment. As a preferred combination of the present invention, the first, fourth, fifth, and sixth embodiments can be combined. Through this combination, the order of HARQ-ACK bits can be first determined in the HARQ-ACK codebook based on the time domain information of the PDCCH, and when the order cannot be determined based on the time domain information, the order can be determined based on the cell information, and when the order cannot be determined based on the cell information, the order can be determined based on the CORESET (or search space) information, and when the order cannot be determined based on the CORESET (or search space) information, the order can be determined based on the frequency domain allocation information of the PDCCH.

[0271] Another problem to be solved by the present invention relates to the case where the PDCCH for HARQ-ACK corresponding to one HARQ-ACK codebook is included as two types, namely, 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 for the PDSCH scheduled by the DCI with the counter DAI field and the HARQ-ACK for the PDSCH scheduled by the DCI without the counter DAI field.

[0272] As an embodiment of the present invention, in the above case, the UE generates a first sub-HARQ-ACK codebook by collecting only the HARQ-ACK of the PDSCH scheduled by the DCI with the 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 (ie, 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 the HARQ-ACK of the PDSCH scheduled by the DCI without the 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 (ie, 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.

[0273] As another embodiment of the present invention, in the above case, even for DCI with a counter DAI field, the UE may ignore the counter DAI field. That is, it may be assumed that all DCIs do not have a counter DAI field, and a combination of the first to sixth embodiments may be used to determine the position of the HARQ-ACK bit in the HARQ-ACK codebook.

[0274] Another invention to be solved by the present invention relates to a method for reducing the payload size of DCI. Similar to the above-mentioned method of not including the K1 or PRI field to reduce the DCI overhead, another DCI field may not be included or only some options that the DCI field can indicate may be included. Here, when only some options (for example, N options) that can be 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^XN code points of the corresponding DCI field cannot be used. Here, X is the minimum value of the integers that satisfy the condition that 2^X is equal to or greater than N. Therefore, in order to utilize it more effectively, different DCI fields need to be jointly encoded.

[0275] As one embodiment of the present invention, assume that the jth DCI field includes Y(j) options (option 0, option 1, option 2, etc.). After receiving DCI from the base station, the UE can obtain the order of the options in the jth DCI field from the following equation. Here, the order starts from option 0 (i.e., the first option is option 0).

[0276] Field(j)=floor(X / Z(j))mod Y(j)

[0277] Among them, for j>1, and And for j=1, Z(1)=1. In addition, DCI_length is the length of DCI, b k The received DCI is expressed in binary. That is, according to the above equation, the option corresponding to Field(j) (the Field(j) option) can be selected from the j-th DCI.

[0278] For example, the following table covers the case where the DCI includes three fields, each of which includes three options. When calculating the 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.

[0279] [Table 4]

[0280]

[0281]

[0282] For example, when the UE receives an indication of 01100 as DCI, the UE may obtain Field(1)=0, Field(2)=1, and Field(3)=1. That is, it can be understood that the Field(1)=0 option is indicated in the first DCI field, the Field(2)=1 option is indicated in the second DCI field, and the Field(3)=1 option is indicated in the third DCI field.

[0283] 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 odd-numbered symbols of the time slot, and the second sub-time slot can be configured with the even-numbered symbols of the time slot. In summary, 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 N sub-slots, (K mod N) sub-slots with one more symbol can be located at the front of the slot, and N-(K mod N) sub-slots with one less symbol can be located at the back of the slot. Among N sub-slots, N-(K mod N) sub-slots with one less symbol can be located at the front of the slot, and (K mod N) sub-slots with one more symbol can be located at the back of the slot. Among N sub-slots, (K mod N) sub-slots with one more symbol and N-(K mod N) sub-slots with one less symbol can be positioned alternately. In summary, by using the second method to divide a slot configured with K symbols into N sub-slots, the nth sub-slot can be configured with floor(K / N)*i+nth symbols (i=0,1,...).

[0284] Alternatively, the UE can divide subslots based on the configured PDSCH time domain resource assignment information. For example, subslots can be divided based on the position of the last PDSCH symbol in the PDSCH time domain resource assignment information. The last symbol of the last multiple PDSCH symbols up to the most recent one can be divided into the first subslot. The remaining subslots can be divided continuously using the above scheme.

[0285] According to another method, the UE can divide subslots based on the configured PUCCH occupied symbols. For example, subslots can be divided according to the position order of the last PUCCH symbol in the PUCCH occupied symbols information. The last symbol of the first A PUCCHs can be divided into the first subslot. The remaining subslots can be divided continuously using the above method.

[0286] 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-slot. More specifically, the problem to be solved is as follows.

[0287] Figure 20 FIG2 is a diagram illustrating configuration of PDSCH candidates for time slots.

[0288] refer to Figure 20 , assuming that there are three PDSCH candidates in a time slot. PDSCH candidate #1 is included in the first sub-time slot (here, whether the PDSCH candidate is included is determined based on 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 number of PDSCH candidates that a UE can receive simultaneously in the corresponding time slot is at most two. For example, the situations that can be received are {PDSCH candidate #1}, {PDSCH candidate #2}, {PDSCH candidate #3}, {PDSCH candidate #1, PDSCH candidate #3} and {PDSCH candidate #2, PDSCH candidate #3}. On this basis, the number of HARQ-ACK bits that the UE should include in the semi-static HARQ-ACK codebook of the PDSCH candidate of the corresponding time slot is 2. (Here, it is assumed that one PDSCH candidate sends 1-bit HARQ-ACK) When the granularity of K1 is given as half a 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 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 above case where the maximum number of PDSCHs that can be transmitted in one time slot is two and a 2-bit HARQ-ACK is included in the semi-static HARQ-ACK codebook, an unnecessary 1-bit overhead occurs. The present invention proposes a method for reducing such overhead.

[0289] As one 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 sub-slots included in a slot and using the PDSCH candidates included in the sub-slot. The semi-static HARQ-ACK codebook to be transmitted in sub-slot n can be generated as follows.

[0290] Figure 21 is a diagram illustrating a process of excluding overlapping PDSCH candidates according to an embodiment of the present invention.

[0291] refer to Figure 21 , 1) The set of K1 values ​​that can be indicated is called K1_set. The maximum K1 value is taken from K1_set. This is called K1_max. The index of the time slot in which the sub-time slot corresponding to n-K1_max is included is called X. N_subslot sub-time slots are configured in one time slot, and X satisfies X=floor((n-K1_max) / N_subslot). The K1 value indicating the sub-time slot included in time slot X is taken from K1_set. That is, when an element in the 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 ​​taken during the above process (including K1_max) is called K1_max_set. The taken K1 value is excluded from K1_set.

[0292] 2) The set of PDSCH candidates that can be received in a time slot is referred to as R. If the last subslot among the subslots that overlap with the DL time slot of the PDSCH candidate included in the set R is included in the subslots included in K1_max_set, the PDSCH candidate is maintained in the set R, or otherwise excluded from the set R. Further, if the symbol of the PDSCH candidate included in the set R overlaps with a symbol configured as uplink in a semi-static UL / DL configuration, the PDSCH candidate is excluded from the set R.

[0293] 3) The UE performs the following steps A and B on the PDSCH candidates included in R.

[0294] A. A new 1 bit is allocated to the PDSCH candidate with the first last symbol. In addition, if there is a PDSCH candidate in set R that overlaps with the above PDSCH candidate in at least one symbol, then the PDSCH candidate is allocated the same bit position as the PDSCH candidate with the first last symbol. The above PDSCH candidates (including the PDSCH candidate with the first last symbol) are excluded from set R.

[0295] B. Repeat step 3-A above until the set R becomes empty.

[0296] 4) Repeat the above steps 1), 2), and 3) until K1_set becomes an empty set.

[0297] Another problem of the present invention is to provide a specific design method of the type-1 HARQ-ACK codebook when configuring sub-slots.

[0298] According to one embodiment of the present invention, the UE includes a K1 value (hereinafter referred to as K1) configured at a sub-slot granularity. 1,k ) is converted to the K1 value of the time slot level (hereinafter referred to as K 1,k,slot ) process.

[0299] In more detail, the K1 value at the time slot level can be determined as follows.

[0300]

[0301] Here, n U Indicates the index of the subslot in which the PUCCH is transmitted, and N indicates the number of subslots in one slot. For example, when 14 symbols are configured in one slot, N is one of the values ​​​​2 to 7, and when 12 symbols are configured in one slot, N is one of the values ​​​​2 to 7. Here, Represents the largest integer among the numbers equal to or less than x.

[0302] Figure 22 is a diagram illustrating a process of generating a Type-1 HARQ-ACK according to an embodiment of the present invention.

[0303] refer to Figure 22 , the subcarrier spacing of the downlink cell of the UE is 30kHz, and the subcarrier spacing of the uplink cell is 15kHz. The time slot of the uplink cell is divided into seven subslots by combining every two consecutive symbols. That is, N=7. In order to U =12), the UE shall generate a Type-1 HARQ-ACK codebook to be included in the PUCCH. The K1 value configured at the sub-slot granularity is K1 = {8, 7, 4, 3}.

[0304] refer to Figure 22 According to one embodiment of the present invention, the K1 value configured at the sub-time slot granularity can be converted into the K1 value K at the time slot granularity. 1,k,slot The conversion is performed as follows.

[0305]

[0306] The UE can use the K obtained in this way 1,k,slotThe value is used to determine the PDSCH candidates in each time slot. More specifically, when K 1,k When the pseudo code for generating the type-1 HARQ-ACK codebook is executed in descending order, the pseudo code for generating the type-1 HARQ-ACK codebook can be calculated according to each K 1,k Value obtained K 1,k,slot Based on the obtained K 1,k,slot The value generates the type-1 HARQ-ACK codebook.

[0307] The UE can check the validity of the PDSCH candidate to determine the optimal value based on the previously selected K 1,k The value determines whether the PDSCH candidate should be included in the type-1 HARQ-ACK codebook. 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. The process can be determined based on whether the last symbol (end time) of the PDSCH candidate is included in a specific sub-slot. If it is determined that the last symbol (end time) of the PDSCH candidate is included in a specific sub-slot, the PDSCH candidate is determined to be valid. Otherwise, the PDSCH candidate is determined to be invalid. Here, the specific sub-slot is sub-slot n U -K 1,k .

[0308] Figure 23 is a diagram illustrating a process of generating a Type-1 HARQ-ACK according to an embodiment of the present invention.

[0309] refer to Figure 23 , when K 1,0 = 8 is selected, the UE shall determine the PDSCH candidate for DL ​​slot 1 for subslot n U -K 1,0 = Is sub-time slot 4 valid? Figure 23 In the embodiment of , it is assumed that two PDSCH candidates are configured for the UE. Figure 23 In the example, the first PDSCH candidate is marked as "A" and the second PDSCH candidate is marked as "B". The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in the subslot n. U -K 1,0 = in subslot 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 subslot 5 instead of subslot n. U -K 1,0 = in subslot 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 subslot n. U -K1,0 = in subslot 4. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0310] refer to Figure 23 , when K 1,1 =7 is selected, the UE shall determine the PDSCH candidate for DL ​​slot 1 for subslot n U -K 1,1 = Whether subslot 5 is valid. The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in subslot n U -K 1,1 = in subslot 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 subslot n U -K 1,1 = in subslot 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 subslot 4, not subslot n. U -K 1,1 = in subslot 5. Therefore, the second PDSCH candidate B may be determined to be invalid.

[0311] refer to Figure 23 , when K 1,2 = 4 is selected, the UE shall determine the PDSCH candidate for DL ​​slot 2 for subslot n U -K 1,2 = Whether subslot 8 is valid. The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in subslot n U -K 1,2 = in subslot 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 subslot n U -K 1,2 = in subslot 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 subslot n. U -K 1,2 = in subslot 8. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0312] refer to Figure 23 , when K 1,3 = 3 is selected, the UE shall determine the PDSCH candidate for DL ​​slot 2 for subslot n U -K 1,3= Whether subslot 9 is valid. The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in subslot n U -K 1,3 = in subslot 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 subslot 8 instead of subslot n. U -K 1,3 = in subslot 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 subslot 8 instead of subslot n. U -K 1,3 = in subslot 9. Therefore, the second PDSCH candidate B can be determined to be invalid.

[0313] In more detail, validity is established when the following conditions are met.

[0314] <Validity Conditions>

[0315] If subslotLengthForPUCCH-r16 is provided and subslot n U -K 1,K Is with the time slot The PDSCH time resource in row r is derived as the DL slot overlapping the last UL subslot.

[0316] Here, n U,slot is the same as sub-slot n U The index of the corresponding time slot can be obtained as

[0317] Validity does not hold when the following conditions are met.

[0318] <Invalid Condition>

[0319] If subslotLengthForPUCCH-r16 is provided and subslot n U -K 1,K Not with time slots The PDSCH time resource in row r is derived as the DL slot overlapping the last UL subslot.

[0320] With this correction, the existing Release 15 / 16 pseudocode for generating Type-1 HARQ-ACK can be minimally corrected and applied to the sub-slot configuration. A more specific first pseudocode is as follows. For reference, all variables here can be referenced to the 3GPP standard document TS38.213.

[0321] <First pseudo code>

[0322] [Table 5]

[0323]

[0324]

[0325]

[0326]

[0327]

[0328]

[0329]

[0330]

[0331]

[0332] The above pseudo code is based on a K 1,k The values ​​can be summarized as follows.

[0333] As a first step, the UE converts the K 1,k The value is converted to K expressed in time slot granularity 1,k,slot The above steps are given in the pseudo code above as

[0334] As a second step, the UE may 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 subslot n U -K 1,k If the PDSCH candidate is determined to be invalid, the PDSCH candidate is excluded from the process of generating the type-1 HARQ-ACK codebook. The above steps are given as follows in the above pseudo code.

[0335] If subslotLengthForPUCCH-r16 is provided and subslot n U -K 1K Not with time slots The row r in the PDSCH time resource is obtained by overlapping the DL time slot with the last UL subslot

[0336] R=R\r;

[0337] According to the above two steps, valid PDSCH candidates may be included in set R. Thereafter, the valid PDSCH candidates in set R may be used to generate a type-1 HARQ-ACK codebook.

[0338] When the Type-1 HARQ-ACK codebook is generated in this manner, the following problems may occur.

[0339] A UE can have various capabilities. When a UE has a specific capability, it can notify the base station of that capability. This is called capability reporting. The base station can determine the transmission and reception methods to use for the UE based on the capability report received from the UE.

[0340] If the UE does not have a specific capability, the UE can receive one PDSCH in one DL slot. In other words, the UE does not expect that the reception of two or more PDSCHs will be indicated or configured for one DL slot. Therefore, for one DL slot, the Type-1 HARQ-ACK codebook generated by the UE only includes the HARQ-ACK for one PDSCH received in one DL slot.

[0341] The UE may be capable of receiving two or more PDSCHs in one DL slot. In this case, the type-1 HARQ-ACK codebook generated by the UE includes, for one DL slot, HARQ-ACK for at least one PDSCH received in one DL slot.

[0342] As mentioned above, the Type-1 HARQ-ACK codebook generation method can vary depending on the capabilities. This is described in pseudo code as follows.

[0343] if the UE has not indicated the capability to receive more than one unicast PDSCH per time slot and

[0344] M A.c =M A.c ∪j;

[0345] j=j+1;

[0346] else [...]

[0348] Assume that two or more values ​​are taken as K 1,k The value is provided to the UE. U When a PUCCH including a type-1 HARQ-ACK codebook is sent in the ACK, the type-1 HARQ-ACK codebook is generated as follows. 1,k Value (here called K 1,k1 ) Get subslot n U -K 1,k1and can be obtained with the sub-slot n U -K 1,k1 The corresponding DL time slot. This DL time slot is called the first DL time slot. 1,k Value (here called K 1,k2 ) Get sub-slot K 1,k2 and can be obtained with the sub-slot n U -K 1,k2 The corresponding DL time slot. 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, it is assumed that the first DL time slot and the second DL time slot are the same. For reference, here, with the sub-slot n U -K 1,k1 The corresponding DL time slot can be the same as the sub-time slot n U -K 1,k1 Overlapping DL time slots. Here, with sub-slot n U -K 1,k2 The corresponding DL time slot can be the same as the sub-time slot n U -K 1,k2 Overlapping DL time slots.

[0349] Assume that the UE does not have a specific capability. According to the first pseudo code, if in this example the 1,k Value (here called K 1,k1 ), there is at least one valid PDSCH candidate in the first DL time slot, the UE includes one HARQ-ACK for the PDSCH candidate of the first DL time slot in the type-1 HARQ-ACK codebook. As described above, since the UE can only 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. 1,k Value (here called K 1,k2 ), if there is at least one valid PDSCH candidate in the second DL time slot of the UE, one HARQ-ACK of the PDSCH candidate of 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 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 only receive at most one PDSCH in one DL time slot, the UE can include only one HARQ-ACK; however, since more HARQ-ACKs, i.e., two HARQ-ACKs, are included, the problem of an increase in the size of the type-1 HARQ-ACK codebook occurs.

[0350] refer to Figure 23 , corresponding to K 1,0 The DL time slot of K 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 one HARQ-ACK for the above DL time slot. Next, corresponding to K 1,1 The DL time slot of the UE 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 one 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.

[0351] The present invention proposes a method to solve this problem.

[0352] According to one embodiment of the present invention, if the 1,k If there is at least one valid PDSCH candidate in the DL time slot of the value, the UE includes one HARQ-ACK for the PDSCH candidate of the DL time slot in the type-1 HARQ-ACK codebook. Here, the UE can 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 is already 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.

[0353] In this way, the UE can include only one HARQ-ACK in the Type-1 HARQ-ACK codebook for one DL slot. When the UE receives a PDSCH in a DL slot, the HARQ-ACK for the PDSCH can be sent at the bit position in the Type-1 HARQ-ACK codebook corresponding to the received DL slot.

[0354] refer to Figure 23 , corresponding to K 1,0 The DL time slot of K 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 HARQ-ACK for DL ​​time slot 1. Next, corresponding to K 1,1The DL time slot of UE 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 is therefore 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.

[0355] According to the first pseudo code above, a K1 value is taken from a K1 set, a valid PDSCH candidate is determined based on the K1 value, and the HARQ-ACK bit position between the valid PDSCH candidates is determined. Here, the granularity of the K1 value is the sub-slot. That is, a valid PDSCH candidate is determined within a sub-slot, and the HARQ-ACK bit position is determined between the valid PDSCH candidates. However, since the PDSCH is scheduled in units of time 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 time slot.

[0356] For example, reference Figure 23 , for K 1,0 =8, the UE obtains the corresponding DL time slot 1 and checks the validity of the two PDSCH candidates A and B in DL time slot 1. 1,1 =7, the UE obtains the corresponding DL time slot 1 and checks the validity of the two PDSCH candidates A and B in DL time slot 1. 1,0 The operations performed are redundantly on K 1,1 implement.

[0357] In order to avoid this redundant operation, it is expected that the UE will 1,k Convert to K 1,k,slot And according to K 1,k,slot The validity of the PDSCH candidate is determined by obtaining the DL time slot corresponding to K 1,k The validity of the PDSCH candidate is determined by the DL time slot of each sub-time slot.

[0358] According to one embodiment of the present invention, the UE includes a K1 value (hereinafter referred to as K1) configured at a sub-slot granularity. 1,k ) is converted to the K1 value of the time slot level (hereinafter referred to as K 1,k,slot ) process.

[0359] In more detail, the K1 value at the time slot level can be determined as follows.

[0360]

[0361] K 1,k,slot The set of values ​​is called K 1,slot For reference, two or more K 1,k May have the same K 1,k,slot In other words, multiple K 1,k,slot The value can correspond to K 1,slot A K of the set 1,k,slot value.

[0362] Return Reference Figure 22 , K can be obtained as follows 1,k,slot .

[0363]

[0364] Therefore, K 1,slot is determined so that K 1,slot ={1,0}.

[0365] UE can use K 1,slot K of the set 1,k,slot The type-1 HARQ-ACK codebook is generated in descending order of K 1,slot Take the largest K in the set 1,k,slot The K value is determined by 1,k,slot The valid PDSCH candidates for the corresponding DL time slot. Next, we can 1,slot Take the second largest K in the set 1,k,slot value to determine the K 1,k,slot The valid PDSCH candidate of the corresponding DL time slot can be repeated until the K 1,slot Take the smallest K in the set 1,k,slot The value corresponding to K 1,k,slot Valid PDSCH candidates for the DL time slot.

[0366] The UE can check the validity of the PDSCH candidate to determine whether the PDSCH candidate should be selected based on the previously selected K 1,k,slot The value is included in the type-1 HARQ-ACK codebook. If valid, the PDSCH candidate may be included, otherwise the PDSCH candidate may be excluded. The process may 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 compared with K 1,k,slot The K value corresponding to 1,k The value is defined as K 1,k1 , K 1,k2 , ..., sub-slot nU -K 1,k1 , sub-slot n U -K 1,k2 、…。

[0367] refer to Figure 23 , when choosing K 1,0,slot = 1, the UE shall determine the subslot n U -K 1,0 = subslot 4 and subslot n U -K 1,1 = Subslot 5, whether the PDSCH candidate of DL slot 1 is valid. For reference, K 1,0,slot =1 corresponds to K 1,0 =8 and K 1,1 =7. Figure 23 In the embodiment of , it is assumed that two PDSCH candidates are configured for the UE. Figure 23 In the example, the first PDSCH candidate is marked as "A" and the second PDSCH candidate is marked as "B". The UE can determine whether the last symbol (end time) of each PDSCH candidate is included in the subslot n. U -K 1,0 = Subslot 4 or Subslot n U -K 1,1 = in subslot 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 subslot n U -K 1,1 = in subslot 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 subslot n. U -K 1,0 = in subslot 4. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0368] refer to Figure 23 , when choosing K 1,1,slot = 0, the UE shall determine the subslot n U -K 1,2 = subslot 8 and subslot n U -K 1,3 = Subslot 9, whether the PDSCH candidate of DL slot 2 is valid. For 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 the subslot n U -K 1,2 = subslot 8 or subslot nU -K 1,3 = in subslot 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 subslot n U -K 1,2 = in subslot 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 subslot n. U -K 1,2 = in subslot 8. Therefore, it can be determined that the second PDSCH candidate B is valid.

[0369] In more detail, validity is established when the following conditions are met.

[0370] <Validity Conditions>

[0371] If subslotLengthForPUCCH-r16 is provided and subslot n U -K 1K At least one of the time slots The row r in the PDSCH time resource is derived as the DL time slot overlaps the last UL subslot, where K 1,k With K 1,K,slot associated.

[0372] Here, n U,slot is the same as sub-slot n U The index of the corresponding time slot can be obtained as

[0373] Validity does not hold when the following conditions are met.

[0374] <Invalid Condition>

[0375] If subslotLengthForPUCCH-r16 is provided and all subslots n U -K 1,K Not with time slots The row r in the PDSCH time resource is derived as the DL time slot overlaps the last UL subslot, where K 1,k With K 1,K,slot associated.

[0376] This is invalid if the last symbol of the PDSCH candidate is not included in all subslots.

[0377] With this correction, the existing Release 15 / 16 pseudocode for generating Type-1 HARQ-ACK can be minimally corrected and applied to sub-slot configurations. A more specific pseudocode is as follows. For reference, all variables here can be referenced to 3GPP standard document TS 38.213.

[0378] <Second pseudo code> [Table 6]

[0379]

[0380]

[0381]

[0382]

[0383]

[0384]

[0385]

[0386]

[0387]

[0388]

[0389] In the NR wireless communication system, the 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 use an RRC signal to configure the length of the HARQ-ACK codebook and indicate that each bit of the HARQ-ACK codebook indicates which PDSCH ACK / NACK is used for. Therefore, the base station does not have to signal the information required to send the HARQ-ACK codebook every time the HARQ-ACK codebook needs to be sent. The set of PDSCHs whose ACK / NACK is indicated by the semi-static HARQ-ACK codebook is called a PDSCH candidate set. In the following, reference will be made to Figure 24 Describes the method by which a UE determines a PDSCH candidate set.

[0390] The UE determines the PDSCH candidate set based on the information signaled from the base station. Here, the information signaled from the base station may 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 sent. Fallback DCI (DCI format 1_0) can indicate the K1 value as one of 1, 2, 3, 4, 5, 6, 7, and 8. Non-fallback DCI (DCI formats 1_1 to 1_2) can indicate one of up to eight values ​​configured by the RRC signal as the K1 value. In addition, the information signaled from the base station may include a combination of the length of the PDSCH in the time slot and the starting symbol of the PDSCH, as well as 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 in the time slot and the length of the PDSCH can be encoded in the form of a start and length indicator value (SLIV) value. The base station can signal up to 16 K0 values ​​and a 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 in the time slot.

[0391] In addition, the information notified by signaling from the base station may include a semi-static DL / UL configuration. The semi-static DL / UL configuration represents the symbol configuration information of the time slot configured by a cell-specific RRC signal or a UE-specific RRC signal. In detail, the configuration may indicate whether each symbol included in the 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 the PDSCH corresponds to a UL symbol. This is because the PDSCH cannot be received on the symbol corresponding to the UL symbol. In a specific embodiment, where any one of the symbols allocated with the PDSCH corresponds to a UL symbol, the UE may not include the corresponding PDSCH in the PDSCH candidate set. All symbols to which the PDSCH is allocated do not correspond to UL symbols, and the UE may include the corresponding PDSCH in the PDSCH candidate set.

[0392] In addition, the information signaled from the base station may include information on the configuration of the CORESET and the search space. The information on the configuration of the CORESET and the search space may indicate at which position in which time slot the PDCCH can be received.

[0393] In addition, the information notified by the signal from the base station may include a PDSCH repetition value. When receiving 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 use the same length to receive the PDSCH 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 conditions for including the corresponding PDSCH in the PDSCH candidate set are met based on whether the PDSCH may be received in all time slots in which the PDSCH is received. In detail, when the UE determines that PDSCH reception is impossible in all time slots in which it is indicated that the PDSCH is repeatedly received, the UE may not include the corresponding PDSCH in the PDSCH candidate set. In another embodiment, when a PDSCH may be received in any one of the time slots in which reception of the PDSCH is indicated, the UE may include the corresponding PDSCH in the PDSCH candidate set.

[0394] Based on whether the PDSCH candidate indicated by SLIV is valid for each of a plurality of K1 values ​​and K0, the UE includes a combination of the K1 value, K0, and each of the PDSCH candidates indicated by SLIV in the PDSCH candidate set. It can be determined whether the PDSCH candidate indicated by SLIV is valid for each of a plurality of K1 values ​​and K0. When the combination of the corresponding K1 value, K0, and the PDSCH candidate indicated by SLIV is valid, the UE may include the combination of the corresponding K1 value, K0, and the PDSCH candidate indicated by 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 to which the SLIV indicates that the PDSCH is allocated corresponds to the n-K1th time slot, the n-K1-1th time slot, ..., the n-K1-(Nth) time slot. rep -1) time slots, 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 Indicates the number of time slots in which PDSCH is repeatedly received. As mentioned above, N can be set by RRC signaling rep In addition, when PDSCH repetition is not used, N rep Can make N rep= 1. When any symbol for which the SLIV indicates that the PDSCH is allocated corresponds to a 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 the SLIV indicates that any symbol for which the PDSCH is allocated corresponds to a 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. rep -1) When there is no search space in the K0 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 make N rep = 1. In detail, when SLIV indicates that all symbols to which PDSCH is allocated do not correspond to the n-K1th time slot, the n-K1-1th time slot, ... and the n-K1-(N rep -1) time slots, and the search space exists in the n-K1-(N rep -1)-K0 time slot, the UE may determine that the PDSCH candidate indicated by 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 SLIV in the PDSCH candidate set.

[0395] Figure 24 It is illustrated that whether to include a PDSCH candidate indicated by SLIV signaled to a UE in a PDSCH candidate set is determined according to K1 and K0 according to an embodiment of the present invention.

[0396] exist Figure 24 In the embodiment of the present invention, any one of the symbols to which the PDSCH is allocated indicates that the SLIV corresponds to the n-K1th time slot, the n-K1-1th time slot, ... and the n-K1-(N rep -1) UL symbols in the corresponding time slot among all time slots. Therefore, the UE determines that the PDSCH candidate indicated by SLIV is invalid for the corresponding K1 value and K0. The UE does not include the combination of the corresponding K1 value, K0 and the PDSCH candidate indicated by SLIV in the PDSCH candidate set.

[0397] Based on whether a PDSCH candidate of a combination of K1 value, K0, and SLIV included in the PDSCH candidate set overlaps with a 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 the two combinations into one combination. The UE may determine whether a PDSCH candidate of a combination of K1 value, K0, and SLIV included in the PDSCH candidate set overlaps with a 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 a PDSCH candidate of a combination of K1 value, K0, and SLIV included in the PDSCH candidate set overlaps with a 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 candidate of each combination in up to m=n+1,...N combinations. Here, the UE may sequentially perform operations related to overlap determination from n=0 to n=N-1.

[0398] 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 of the 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 indicating the ACK / NACK of the corresponding PDSCH in the HARQ-ACK codebook. In detail, the position of the HARQ-ACK information of the PDSCH with the last symbol in front may also be in front. For example, when the last symbol of the first PDSCH is before the last symbol of the second PDSCH, the bit indicating the ACK / NACK of the first PDSCH in the HARQ-ACK codebook may be before the bit indicating the ACK / NACK of the second PDSCH.

[0399] The UE can transmit 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 can be transmitted by the PUCCH. This can be configured in the base station or can be determined using at least one of the maximum code rate and number of symbols set for the PUCCH, the number of PRBs, and the number of DM-RS symbols for the PUCCH. If the number of UCI bits is greater than the maximum number of bits that can be transmitted by the PUCCH, the UE cannot transmit all DCI and may not transmit certain UCI types.

[0400] For example, CSI part 2 can be excluded. If the number of bits of UCI is still greater than the maximum number of bits even when CSI part 2 is excluded, then CSI part 1 can be excluded. If the number of bits of UCI is still greater than the maximum number of bits even when CSI part 1 is excluded, then SR can be excluded. If the number of bits of UCI is still greater than the maximum number of bits even when SR is excluded, then a process (bundling) can be performed to discard or combine part or all of the HARQ-ACK. Thereafter, the present invention relates to a method for reducing the number of bits of HARQ-ACK.

[0401] 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, even if the UE fails to receive a certain PDSCH, the size of the semi-static HARQ-ACK codebook transmitted by the UE is the same.

[0402] In a specific case, the UE may not be able to transmit a given semi-static HARQ-ACK codebook. At this time, the UE can only transmit the HARQ-ACK bits of some PDSCHs in the semi-static HARQ-ACK codebook, or can combine and transmit the information of the HARQ-ACK bits of some or all PDSCHs in the semi-static HARQ-ACK codebook. Here, transmitting only the HARQ-ACK bits of some PDSCHs is called discarding, and combining and transmitting the information of some or all bits is called bundling.

[0403] Discarding means transmitting only the HARQ-ACK bits of some PDSCHs in the semi-static HARQ-ACK codebook without transmitting the HARQ-ACK bits of other PDSCHs. Through this process, the UE can reduce the size (i.e., the number of bits) of the semi-static HARQ-ACK codebook. For example, assume that the size of the semi-static HARQ-ACK codebook is A bits. If the number of bits that the UE can transmit is B bits (B < A), then the UE should only select and transmit 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.

[0404] 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 transmitted when discarding is performed.

[0405] Bundling is a scheme for combining and transmitting the information of HARQ-ACK bits of some or all of the PDSCHs in a semi-static HARQ-ACK codebook, and the combination scheme can be as follows. If all the HARQ-ACK bits to be combined are ACKs, 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.

[0406] The problem to be solved by the present invention relates to a method for determining the PDSCH for which HARQ-ACK information is to be combined when bundling is performed.

[0407] The first to fourth embodiments are embodiments applicable to the case where the UE receives PDSCHs in one cell. The first embodiment is applicable to the case of receiving PDSCHs in multiple cells (i.e., the case of carrier aggregation (CA)).

[0408] As a first embodiment, when the number of HARQ-ACK bits (here A bits) included in the semi-static HARQ-ACK codebook 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.

[0409] As a second embodiment, the UE can transmit some bits of the semi-static HARQ-ACK codebook and can not transmit other bits. Here, the selection of some bits to be transmitted can be based on the positions of the bits in the semi-static HARQ-ACK codebook. Preferably, some bits to be transmitted can be the bits arranged in the front positions in the semi-static HARQ-ACK codebook.

[0410] 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 can only select and transmit the first B bits from the semi-static HARQ-ACK codebook.

[0411] Figure 25 It is a diagram illustrating a method for reducing the HARQ-ACK size according to an embodiment of the present invention.

[0412] 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 PDSCH are generated according to each K1 value. That is, [b0 b1 b2 b3] which are the HARQ-ACK bits for 4 PDSCH are generated according to the K1(1) value, and [b4 b5 b6 b7] which are the HARQ-ACK bits for 4 PDSCH are generated according to the K1(2) value. In addition, the UE sends [b0 b1 b2 b3 b4 b5 b6 b7] using the semi-static HARQ-ACK codebook.

[0413] In Figure 25 In the embodiment, if the UE should only select and send B = 5 bits, the UE should select 5 bits from A = 8 bits. According to the second embodiment, the UE can select the first 5 bits from A = 8 bits. These may be [b0 b1 b2 b3 b4].

[0414] Although the method of selecting some bits has been described with respect to the second embodiment, this can be partially replaced by PDSCH. More specifically, assume that the semi-static HARQ-ACK codebook includes the HARQ-ACK bits of A number of PDSCH. The number of HARQ-ACK bits corresponding to the corresponding PDSCH can be the same or different. Further, the number of HARQ-ACK bits corresponding to the corresponding PDSCH can be 1 bit or multiple bits. The UE can select the HARQ-ACK bits of the PDSCH arranged in the front position in the semi-static HARQ-ACK codebook as the bits to be sent. Here, when the HARQ-ACK bits of a certain PDSCH are partially but not all included in the semi-static HARQ-ACK codebook, all the HARQ-ACK bits of this PDSCH are excluded.

[0415] 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 send is B bits (B < A), 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 in the PDSCH corresponding to the B HARQ-ACK 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 sent. 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.

[0416] 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.

[0417] 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 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, calculates the HARQ-ACK bit length 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 may be determined by including only the HARQ-ACK bits of the previous time slots and not including the HARQ-ACK bits of the next time slot.

[0418] Figure 26 is a diagram illustrating a method for reducing the HARQ-ACK size according to an embodiment of the present invention.

[0419] Reference Figure 26 , if the UE should only select and transmit B = 5 bits, the UE calculates the HARQ-ACK bits of the earliest time slot (here, time slot n-K1(1)). Here, the calculated HARQ-ACK bits are [b0 b1 b2 b3], which is 4 bits. Since this is less than B = 5 bits, the HARQ-ACK bits of the next time slot may be calculated. The HARQ-ACK bits calculated by including the next time slot (here, time slot n-K1(2)) are [b0 b1 b2 b3 b4 b5 b6 b7], which is 8 bits. Therefore, the UE may 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.

[0420] In the second and third embodiments, the UE only transmits the HARQ-ACK of the PDSCH of a specific time slot (here, time slot n-K1(1)), and cannot transmit the HARQ-ACK of 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, the HARQ-ACK of some time slots may not be transmitted. Embodiments for solving this problem will be disclosed.

[0421] As a fourth embodiment, the UE may allocate transmittable bits to each time slot, so that the UE can select the bits to be transmitted. More specifically, the transmittable bits are allocated to time slots according to the K1 value in the semi-static HARQ-ACK codebook, thereby determining the bits to be transmitted.

[0422] For example, when the number of bits that the UE can send is A bits and the K1 value is K, the number of bits to be sent in each time slot can be determined based on the A and K1 values. For example, the number 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 sent in each time slot. When the number of bits that can be sent in each time slot is determined, the UE can determine the bits to be sent and the bits not to be sent in each time slot. Preferably, the first bits in the time slot can be determined as the bits to be sent, and the following bits can be determined as the bits not to be sent.

[0423] Figure 27 is a diagram illustrating a method for reducing a HARQ-ACK size according to an embodiment of the present invention.

[0424] refer to Figure 27 , if the UE should select and send only B=4 bits, the UE can send only two bits in each time slot (time slot n-K1(1) and time slot n-K1(2)). Therefore, only the two preceding bits can be selected in each time slot to send [b0 b1 b4 b5].

[0425] The above embodiment is described with respect to one cell. However, in the above embodiment, the time slot can be replaced by a cell, and thus the above method can be understood as a method in which some HARQ-ACK bits of different cells are selected and sent.

[0426] When a UE is configured to receive PDSCHs from two or more cells (ie, in case of carrier aggregation (CA)), the following may be considered.

[0427] First, in the case of CA, the UE can be configured with different reception methods for each cell. Here, the reception methods may include a TB-based PDSCH reception method, a CBG-based PDSCH reception method, a reception method including 1TB per PDSCH, and a reception method including 2TB 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 send, considering that different cells have different reception methods, the following method needs to be adopted.

[0428] As a first method, when 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 TB-based PDSCH reception in the cell. Here, the ACK / NACK of the TB-based PDSCH reception is determined based on whether the TB-CRC is successful. That is, 1 bit HARQ-ACK is generated per TB. Alternatively, 1 bit per TB generated by the TB-based PDSCH reception can be obtained by bundling 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 TB-based PDSCH reception is equal to or less than the number of transmittable bits (here, B bits), the UE can send the semi-static HARQ-ACK codebook. When the size of the semi-static HARQ-ACK codebook generated by assuming TB-based PDSCH reception is greater than the number of transmittable bits (here, B bits), the UE cannot send the semi-static HARQ-ACK codebook. In this case, additional HARQ-ACK bits need to be dropped or bundled. This will be described later.

[0429] Figure 28 is a diagram illustrating a method for reducing a HARQ-ACK size in case of carrier aggregation according to an embodiment of the present invention.

[0430] refer to Figure 28 (a) and (b), 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 1TB per PDSCH, another cell CC#1 is configured for TB-based PDSCH reception and receives 2TB per PDSCH, and another cell CC#2 is configured for CBG-based PDSCH reception and receives 1TB per PDSCH. 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 generated according to CBG-based PDSCH reception of CC#2 (M 21 、M 22 、M 23 and M 34 ). The number of HARQ-ACK bits generated as a result (N 21 、N 22 、N 23 and N 24 ) is 1 bit per PDSCH.

[0431] As a second method, the UE may generate a semi-static HARQ-ACK codebook by assuming TB-based PDSCH reception for 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 transmit, the semi-static HARQ-ACK codebook is transmitted. If the semi-static HARQ-ACK codebook is larger than the number of bits that the UE can transmit, 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 transmit, the semi-static HARQ-ACK codebook is transmitted. 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 larger 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 dropped or bundled. This will be described later.

[0432] As a third method, when 2 TBs are received per PDSCH configured 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 bits. 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 transmittable bits (here B bits), the UE can send 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 transmittable bits (here B bits), the UE cannot send the semi-static HARQ-ACK codebook. In this case, additional HARQ-ACK bits need to be dropped or bundled. This will be described later.

[0433] refer to Figure 28 (a) and (c), according to the third method, the UE can spatially bundle the ACK / NACK of 2 TBs of one PDSCH in order to reduce the number of HARQ-ACK bits generated according to the configuration of receiving 2TB per PDSCH of CC#1 (L 21 , L 22 , L 23 and L 34 ). The number of HARQ-ACK bits generated as a result (N 21 、N 22 、N23 and N 24 ) is 1 bit per PDSCH.

[0434] As a fourth method, similar to the second method, the UE may generate a semi-static HARQ-ACK codebook by sequentially spatially bundling cells in which 2-TB reception per PDSCH is configured one by one, and may determine whether transmission is possible.

[0435] The following preferred embodiment can be configured by combining the first and third methods. In this preferred embodiment, the UE generates a semi-static HARQ-ACK codebook by assuming TB-based PDSCH reception in a cell where 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.

[0436] The detailed operation is described as follows. When CBG-based PDSCH reception and 2TB reception per PDSCH are configured in a cell, the UE generates a semi-static HARQ-ACK codebook by assuming the CBG-based PDSCH reception as TB-based PDSCH reception in the cell. When the size of the semi-static HARQ-ACK codebook generated by assuming TB-based PDSCH reception is equal to or less than the number of transmittable bits (here B bits), the UE can send a 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 bits. 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 transmittable bits (here B bits), the UE can send 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 transmittable bits (here B bits), the UE cannot send the semi-static HARQ-ACK codebook. In this case, additional HARQ-ACK bits need to be dropped or bundled, which will be described later.

[0437] refer to Figure 28 (a), (b) and (d), 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 generated according to CBG-based PDSCH reception of CC#2 (M 21 、M 22 、M 23 and M 34 ). The number of HARQ-ACK bits generated as a result (N21 、N 22 、N 23 and N 24 ) is 1 bit 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 send, the third method is additionally performed. According to the third method, the UE can spatially bundle the ACK / NACK of 2 TBs of one PDSCH to reduce the number of HARQ-ACK bits generated according to the configuration of receiving 2TB per PDSCH of CC#1 (L 21 , L 22 , L 23 and L 34 ). The number of HARQ-ACK bits generated as a result (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.

[0438] Through the first method to the fourth method, the UE can have 1 HARQ-ACK bit per PDSCH equally for each cell. If the size of the semi-static HARQ-ACK codebook is larger 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 to be described later can be additionally applied to the first method to the fourth method. Unless otherwise specified, the discarding or bundling of HARQ-ACK bits to be described later can also be used even when the first method to the fourth method are not used (i.e., when the HARQ-ACK codebook includes multiple HARQ-ACK bits per PDSCH).

[0439] As a fifth embodiment, the UE may generate a semi-static HARQ-ACK codebook including HARQ-ACK bits of some cells and may transmit the semi-static HARQ-ACK codebook. Here, some cells may be selected based on a cell index.

[0440] Figure 29 is a diagram illustrating a method for reducing a HARQ-ACK size in case of carrier aggregation according to an embodiment of the present invention.

[0441] Reference Figure 29(a), if the UE is configured to receive PDSCH from three cells CC#0, CC#1, and CC#2, the UE may generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of CC#0. However, if the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 02 +N 03 +N 04 ) 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 dropping 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 of the semi-static HARQ-ACK codebook (N 01 +N 02 +N 03 +N 04 ) is equal to or less than the number of bits that the UE can send, the UE may send a semi-static HARQ-ACK codebook. In addition, the UE may generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of the 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 send, the UE can send a semi-static HARQ-ACK codebook. 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 send, the UE may generate a semi-static HARQ-ACK codebook generated using cells up to the previous index except for cell CC#1.

[0442] As a sixth embodiment, the UE may generate a semi-static HARQ-ACK codebook including HARQ-ACK bits corresponding to some time slots and may transmit the semi-static HARQ-ACK codebook. Here, some time slots may be selected based on the K1 value.

[0443] refer to Figure 29(b), if the UE is configured to receive the 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 may 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 send, the UE cannot send 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 equal to or less than the number of bits that the UE can send, the UE may send a semi-static HARQ-ACK codebook. In addition, the UE may generate a semi-static HARQ-ACK codebook including HARQ-ACK bits for 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 equal to or less than the number of bits that the UE can send, the UE can send a semi-static HARQ-ACK codebook. 01 +N 11 +N 21 +N 02 +N 12 +N 22 ) is greater than the number of bits that the UE can send, the UE can generate a semi-static HARQ-ACK codebook generated using the previous time slot except time slot n-K1(2).

[0444] 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 the HARQ-ACK bits of a specific cell are excluded, the HARQ-ACK bits of all time slots of the cell may not be excluded. In addition, when the HARQ-ACK bits of a specific time slot are excluded, the HARQ-ACK bits of all cells in the time slot may not be excluded.

[0445] As in the fifth embodiment, the UE may generate a semi-static HARQ-ACK codebook configured with HARQ-ACK bits of some cells. Here, when the HARQ-ACK bits of a specific cell are added to the semi-static HARQ-ACK codebook, the UE may sequentially add the HARQ-ACK bits of each time slot of the specific cell. When all the HARQ-ACK bits of all time slots of a specific cell are added or the HARQ-ACK bits of a certain time slot are added, the addition process may be performed until the number of bits that the UE can send is exceeded. If the number of bits that the UE can send is exceeded when adding the HARQ-ACK bits of a certain time slot, a semi-static HARQ-ACK codebook to which the HARQ-ACK bits of the previous time slot up to the time slot are added may be sent. This scheme may be referred to as a K1 value first CC second (K1 value first, CC second) scheme.

[0446] Reference Figure 29 (c), the UE may generate a semi-static HARQ-ACK codebook configured with HARQ-ACK bits for CC#0. The semi-static HARQ-ACK codebook includes N 01 +N 02 +N 03 +N 04 bits. The HARQ-ACK bits of CC#1 as the next cell can be added to the semi-static HARQ-ACK codebook in the order of the time slots of cell CC#1. First, it can be determined whether the HARQ-ACK bits (N) of time slot n-K1(1) corresponding to the K1(1) value are added. 11 bits) are added to the semi-static HARQ-ACK codebook. If the number of bits of the semi-static HARQ-ACK codebook to which the above-mentioned HARQ-ACK bits are added is equal to or less than the number of bits that the UE can send, the above-mentioned 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 of the semi-static HARQ-ACK codebook to which the above-mentioned HARQ-ACK bits are added is greater than the number of bits that the UE can send, the above-mentioned 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).

[0447] 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, the addition process may be performed until the number of bits that the UE can send is exceeded. If the number of bits that the UE can send is exceeded when adding the HARQ-ACK bits of a certain cell, a semi-static HARQ-ACK codebook to which the HARQ-ACK bits of the previous cell of the cell are added may be sent. This scheme may be referred to as the CC first K1 value second scheme.

[0448] Reference Figure 29 (d), the UE can generate a semi-static HARQ-ACK codebook configured with HARQ-ACK bits for time slot n-K1(2). The semi-static HARQ-ACK codebook includes N 01 +N 11 +N 21 +N 02 +N 12 +N 22 bits. The HARQ-ACK bits of the 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 the time slot n-K1(3). First, it can be determined whether the HARQ-ACK bits (N 03 bits) are added to the semi-static HARQ-ACK codebook. If the number of bits of the semi-static HARQ-ACK codebook to which the above HARQ-ACK bits are added is equal to or less than the number of bits that the UE can send, 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 indexed cell CC#1. If the number of bits of the semi-static HARQ-ACK codebook to which the above HARQ-ACK bits are added is greater than the number of bits that the UE can send, 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 indexed cell.

[0449] When the UE generates a semi-static HARQ-ACK codebook, multiple bits may correspond to one time slot. Another method proposed in the present invention is a method of reducing multiple bits when multiple bits correspond to one time slot. With respect to the first to fourth embodiments described above, a discarding scheme has been described in which the UE sends some HARQ-ACK bits and does not send other HARQ-ACK bits. In the following, a bundling scheme will be described instead of a discarding scheme.

[0450] 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 The diagram shows that three PDSCH candidates are configured in one slot.

[0451] -PDSCH candidate A occupies symbols 0 to 13,

[0452] -PDSCH candidate B occupies symbols 0 to 6,

[0453] -PDSCH candidate C occupies symbols 7 to 13.

[0454] The UE can only receive one PDSCH per symbol, and therefore PDSCH candidate A and PDSCH candidate B cannot be scheduled for reception at the same time 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 therefore cannot be scheduled for reception at the same time. 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.

[0455] -{A}, {B}, {C}

[0456] -{B, C}

[0457] refer to Figure 30 , by definition, the Type-1 HARQ-ACK codebook can be configured with HARQ-ACK bits for up to two PDSCHs per time slot. For convenience, it is assumed that the HARQ-ACK for PDSCH is 1 bit. That is, the Type-1 HARQ-ACK codebook is configured with 2 bits for HARQ-ACK information for up to two PDSCHs per time slot. This is referred to as [b0b1]. Here,

[0458] -b0 can send HARQ-ACK information of PDSCH candidate A and PDSCH candidate B.

[0459] -b1 can send HARQ-ACK information of PDSCH candidate C.

[0460] Assume that the UE has received PDSCH candidate A. This may include the case where a 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 bits of the PDSCH received in PDSCH candidate A can be mapped to b0.

[0461] The UE may perform bundling to reduce the HARQ-ACK information of the PDSCH received in one slot of the Type-1 HARQ-ACK codebook. In the above example, [b0 b1] may be bundled into one bit. Here, bundling may be defined as follows.

[0462] - ACK if HARQ-ACK for all bits (b0 and b1) is ACK

[0463] - Otherwise, (if the HARQ-ACK of at least one of all bits (b0 and b1) is NACK), then NACK

[0464] In the above example, when assuming that PDSCH candidate A has been received, [b0b1] is given so that [b0b1]=[b0NACK]. 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.

[0465] The following describes a method for bundling Type-1 HARQ-ACK codebooks according to an embodiment of the present invention.

[0466] - For a bit position in the Type-1 HARQ-ACK codebook, if a PDSCH is received and all corresponding PDSCH candidates associated with that bit position overlap with the received PDSCH, then the bit position is considered to be "X (3rd state)" for bundling

[0467] o Rule A) When bundling, 'X' is considered as "ACK" and a bundling consisting of only bits of "X'" is a NACK.

[0468] o Rule B) First remove 'X' and bundle the remaining states. After bundling, if the bit size is less than the expected size, add NACK

[0469] refer to Figure 30 , bundling according to the above-mentioned embodiment is described as follows.

[0470] According to [b0 b1], the UE can recognize that PDSCH candidate B and PDSCH candidate C cannot be scheduled when receiving the scheduling information of PDSCH candidate A. Therefore, ACK / NACK indicating whether PDSCH candidate A has been successfully received can be mapped to the b0 bit, and "X (third state)" can be mapped to the b1 bit because PDSCH candidate C cannot be scheduled. That is, this can be expressed as [b0 b1] = [b0 X].

[0471] According to Rule A, 'X' is considered as ACK when bundling is performed. Therefore, if b0 and X are bundled into 1 bit, the bundled 1 bit is b0.

[0472] According to Rule B, 'X' is excluded. If it is excluded, the result is [b0]. Therefore, when the bundle is 1 bit, the bundled 1 bit is b0.

[0473] 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 PDSCH candidate A has been scheduled.

[0474] Figure 31 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 31 The figure shows that seven PDSCH candidates are configured in one slot.

[0475] -PDSCH candidate A occupies symbols 0 to 13,

[0476] -PDSCH candidate B occupies symbols 0 to 6,

[0477] -PDSCH candidate C occupies symbols 7 to 13.

[0478] -PDSCH candidate D occupies symbols 0 to 3,

[0479] -PDSCH candidate E occupies symbols 4 to 7,

[0480] -PDSCH candidate F occupies symbols 8 to 11,

[0481] -PDSCH candidate G occupies symbols 12 and 13.

[0482] According to the type-1 HARQ-ACK codebook generation method, 4 bits of HARQ-ACK bits can be generated for the PDSCH candidate of this time slot. This is called [b0 b1 b2 b3]. Here,

[0483] -b0 can send HARQ-ACK information of PDSCH candidate A, PDSCH candidate B or PDSCH candidate D.

[0484] -b1 can send HARQ-ACK information of PDSCH candidate C or PDSCH candidate E.

[0485] -b2 can send HARQ-ACK information of PDSCH candidate F.

[0486] -b3 can send HARQ-ACK information for PDSCH candidate G.

[0487] The combination of UEs allowed to be scheduled simultaneously in one time slot can be expressed as follows.

[0488] o{A},{B},{C},{D},{E},{F},{G}

[0489] o{B,C},{B,F},{B,G},{C,D},{D,E},{D,F},{D,G},{E,F},{E,G},{F,G}

[0490] o{B,F,G},{D,E,F},{D,E,G},{D,F,G},{E,F,G}

[0491] o{D,E,F,G}

[0492] 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, bundling is obtained by performing a binary AND operation on adjacent ACK / NACK. (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 of the 4 bits, and the second bit is obtained by performing a binary AND operation on the following 2 bits. In the case of 1-bit bundling, one bit is obtained by performing a binary AND operation on 4 bits.

[0493] In Table 7, b01 is the result of performing a binary AND operation on b0 and b1, 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.

[0494] As shown in Table 7, in the case of 1-bit bundling, the UE always sends NACK, except when PDSCH candidates {D, E, F, G} are scheduled. Therefore, the information that can be transmitted 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.

[0495] [Table 7]

[0496]

[0497]

[0498] Tables 8 and 9 show HARQ-ACK bundling according to an embodiment of the present invention. Rule A is used in Table 8, and Rule B is used in Table 9.

[0499] Referring to Tables 8 and 9, the UE may determine 'X (third state)' for bundling based on the received scheduling information. This is indicated in the column including the HARQ-ACK for bundling X (third state). For example, when the UE receives scheduling information corresponding to PDSCH candidate A, the UE may 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.

[0500] Referring to Table 8, the UE can bundle a 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 considered an ACK when bundled with other ACK / NACKs. In addition, when bundling is performed between X (third state), X (third state) is considered a NACK. In Table 8, b023 is the result of performing a binary AND operation on b0, b2, and b3.

[0501] 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, a meaningful ACK / NACK 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 / NACK can be sent.

[0502] [Table 8]

[0503]

[0504]

[0505] Referring to Table 8, the UE can generate a HARQ-ACK with X (third state) removed for bundling based on Rule B by excluding 'X (third state)' from the 4-bit HARQ-ACK including X (third state) for bundling. In addition, if the HARQ-ACK with X (third state) removed 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 with X (third state) removed for bundling is less than the number of bits after bundling, NACK can be padded afterwards. For example, in the case of 2-bit bundling, if the HARQ-ACK with X (third state) removed for bundling is 1 bit, the HARQ-ACK is made 2 bits by padded NACK after 1 bit. In the case of 2-bit bundling, if the HARQ-ACK with X (third state) removed for bundling is 2 bits, these 2 bits are the result of bundling. In the case of 2-bit bundling, if the HARQ-ACK after removing X for bundling (third state) is 3 bits, a 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 after removing X for bundling (third state) to obtain 2 bits as a 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.

[0506] As shown in Table 9, 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, a meaningful ACK / NACK can be sent. In the case of 2-bit bundling, the UE sends NACK except when 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 to Table 7, when PDSCH candidates {A}, {B, F}, and {B, F, G} are scheduled, meaningful ACK / NACK can be sent. Compared to Table 8, when PDSCH candidate {C} is scheduled, meaningful ACK / NACK can be sent.

[0507] [Table 9]

[0508]

[0509] Based on 1-bit bundling, the following operations can be considered: In the case of 1-bit bundling, when the UE receives scheduling information of one PDSCH in a time slot, the UE can use the success / failure of PDSCH reception as the result value of the 1-bit bundling.

[0510] 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 schemes of Tables 8 and 9 can be used to obtain 1-bit bundling.

[0511] [Table 10]

[0512] index Received PDSCH HARQ-ACK Recommended Bundling (1-bit Bundling) 1 {A} [b0 NNN] [b0] 2 {B} [b0 NNN] [b0] 3 {C} [Nb1 NN] [b1] 4 {D} [b0 NNN] [b0] 5 {E} [Nb1 NN] [b1] 6 {F} [N Nb2 N] [b2] 7 {G} [NN Nb3] [b3] 8 {B,C} [b0 b1 NN] [N] 9 {B,F} [b0 Nb2 N] [N] 10 {B,G} [b0 N Nb3] [N] 11 {C,D} [b0 b1 NN] [N] 12 {D,E} [b0 b1 NN] [N] 13 {D,F} [b0 Nb2 N] [N] 14 {D,G} [b0 N Nb3] [N] 15 {E,F} [Nb1 b2 N] [N] 16 {E,G} [Nb1 Nb3] [N] 17 {F,G} [N Nb2 b3] [N] 18 {B,F,G} [b0 Nb2 b3] [N] 19 {D,E,F} [b0 b1 b2 N] [N] 20 {D,E,G} [b0 b1 Nb3] [N] 21 {D,F,G} [b0 Nb2 b3] [N] 22 {E,F,G} [Nb1 b2 b3] [N] 23 {D,E,F,G} [b0 b1 b2 b3] [N]

[0513] Assume that the number of bits in the UE's HARQ-ACK codebook 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 less. Here, a specific bundling scheme will be described.

[0514] 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.

[0515] For example, it is assumed 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 each ceil (10 / 3) = 4 bits starting from the front bit 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 a value obtained by performing a binary AND operation on [b0 b1 b2 b3], the second bit is a value obtained by performing a binary AND operation on [b4 b5 b6 b7], and the third bit is a value obtained by performing a binary AND operation on [b8 b9].

[0516] As another example of the first method, the UE bundles every X bits from the front bit of the HARQ-ACK codebook, where X is a power of 2 and is equal to or greater than ceil(A / B).

[0517] As a second method, the UE bundles the ceil(A / B) and floor(A / B) bits of the HARQ-ACK codebook. The number of ceil(A / B) bits bundled is A mod B, and the number of floor(A / B) bits bundled is B-(A mod B). By performing a binary AND operation on the bits included in each bundle, one bit is generated for each bundle.

[0518] For example, assuming that the HARQ-ACK codebook is A = 10 bits (hereinafter [b0 b1 b2 b3 b4 b5 b6 b7 b8 b9]), the number of bits that the UE can send is given as B = 3 bits. According to the second method, the UE can configure the HARQ-ACK codebook as one bundle including 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 a value obtained by performing a binary AND operation on [b0 b1 b2 b3], the second bit is a value obtained by performing a binary AND operation on [b4 b5 b6], and the third bit is a value obtained by performing a binary AND operation on [b7 b8 b9].

[0519] As a third method, the UE divides the HARQ-ACK codebook into B-1 bits and A-(B-1) bits. Furthermore, a 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 B-1 bits with the 1 bit generated above.

[0520] For example, assuming 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 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].

[0521] 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. 1 bit is generated for each bundle by performing a binary AND operation on the bits included in each bundle.

[0522] The foregoing description of the present disclosure is for illustrative purposes, and those skilled in the art will appreciate that modifications to other specific forms 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 and not restrictive in all respects. 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.

[0523] 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 in the scope of the present disclosure.

Claims

1. A user equipment (UE) configured to operate in a wireless communication system, the UE comprising: processor; as well as Communication module, Wherein, the processor is configured to: Downlink control information (DCI) for downlink scheduling is received via a physical downlink control channel (PDCCH), wherein the DCI includes a subslot offset, and the subslot offset is a set K: {k0, k1, ..., k m-1 }(m>0); For each element k of the set K i (k i >0), do one of the following: - If the same as UL sub-time slot # (n u -k i ) overlaps the first downlink (DL) time slot and the UL sub-time slot # (n u -k i-1 ) do not overlap and if there is at least one valid physical downlink shared channel (PDSCH) candidate in the first DL time slot, including hybrid automatic repeat request acknowledgment (HARQ-ACK) information for the first DL time slot in a semi-static HARQ-ACK codebook, and - If the first DL time slot is equal to the UL sub-time slot # (n u -k i-1 ), skipping including the HARQ-ACK information for the first DL time slot in the semi-static HARQ-ACK codebook; and In UL sub-timeslot #n u The semi-static HARQ-ACK codebook is sent via a physical uplink control channel (PUCCH) in Wherein, based on whether the end of the PDSCH candidate in the first DL time slot is in any UL sub-time slot # (n u -k o ) to determine whether the at least one valid PDSCH candidate exists in the first DL time slot.

2. The UE according to claim 1, wherein A DL slot includes 14 symbols, and a UL subslot includes X symbols, where X is at least 2 and less than 14.

3. The UE according to claim 1, wherein: k o is one of a plurality of values ​​corresponding to a UL subslot overlapping with the first DL slot.

4. The UE according to claim 1, wherein: If the UE does not have the capability of receiving more than one PDSCH per DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information for only one PDSCH reception when the at least one valid PDSCH candidate exists in the first DL slot. The UE according to claim 1 , wherein: If the UE has the capability of receiving more than one PDSCH per DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information for one or more PDSCH receptions based on a set of valid PDSCH candidates in the first DL slot. The UE according to claim 5 , wherein: If the UE has the capability of receiving more than one PDSCH per DL time slot, the same HARQ-ACK bit position is assigned to both: (i) a first valid PDSCH candidate with the smallest last symbol index and (ii) zero or more second valid PDSCH candidates that temporally overlap with the first valid PDSCH candidate within the set of valid PDSCH candidates, 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.

7. The UE according to claim 1, wherein: If multiple DL time slots are in UL sub-time 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 of the multiple DL time slots.

8. The UE according to claim 1, wherein: An end of the PDSCH candidate in the first DL slot is determined based on a corresponding start and length indicator value (SLIV).

9. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: Downlink control information (DCI) for downlink scheduling is received via a physical downlink control channel (PDCCH), wherein the DCI includes a subslot offset, and the subslot offset is a set K: {k0, k1, ..., k m-1 }(m>0); For each element k of the set K i (k i >0), do one of the following: - If the same as UL sub-time slot # (n u -k i ) overlaps the first downlink (DL) time slot and the UL sub-time slot # (n u -k i-1 ) do not overlap and if there is at least one valid physical downlink shared channel (PDSCH) candidate in the first DL time slot, including hybrid automatic repeat request acknowledgment (HARQ-ACK) information for the first DL time slot in a semi-static HARQ-ACK codebook, and - If the first DL time slot is equal to the UL sub-time slot # (n u -k i-1 ), skipping including the HARQ-ACK information for the first DL time slot in the semi-static HARQ-ACK codebook; and In UL sub-timeslot #n u The semi-static HARQ-ACK codebook is sent via a physical uplink control channel (PUCCH) in Wherein, based on whether the end of the PDSCH candidate in the first DL time slot is in any UL sub-time slot # (n u -k o ) to determine whether the at least one valid PDSCH candidate exists in the first DL time slot.

10. The method according to claim 9, wherein: A DL slot includes 14 symbols, and a UL subslot includes X symbols, where X is at least 2 and less than 14.

11. The method according to claim 9, wherein: k o is one of a plurality of values ​​corresponding to a UL subslot overlapping with the first DL slot.

12. The method according to claim 9, wherein If the UE does not have the capability of receiving more than one PDSCH per DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information for only one PDSCH reception when the at least one valid PDSCH candidate exists in the first DL slot.

13. The method according to claim 9, wherein: If the UE has the capability of receiving more than one PDSCH per DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information for one or more PDSCH receptions based on a set of valid PDSCH candidates in the first DL slot.

14. The method according to claim 13, wherein If the UE has the capability of receiving more than one PDSCH per DL time slot, the same HARQ-ACK bit position is assigned to both: (i) a first valid PDSCH candidate with the smallest last symbol index and (ii) zero or more second valid PDSCH candidates that temporally overlap with the first valid PDSCH candidate within the set of valid PDSCH candidates, 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.

15. The method according to claim 9, wherein If multiple DL time slots are in UL sub-time 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 of the multiple DL time slots.

16. The method according to claim 9, wherein An end of the PDSCH candidate in the first DL slot is determined based on a corresponding start and length indicator value (SLIV).

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