HARQ-ACK codebook generation method, device, and system in wireless communication system

Abstract

To provide a method for efficiently generating a HARQ-ACK codebook in a wireless communication system, and a device therefor.SOLUTION: One aspect of the present invention discloses a terminal of a wireless communication system. The terminal comprises a communication module and a processor for controlling the communication module. The processor generates a hybrid automatic repeat request (HARQ)-ACK codebook including one or more bits indicating whether reception of a channel or signal is successful, and transmits the HARQ-ACK codebook to a base station of the wireless communication system. The HARQ-ACK codebook is generated on the basis of a slot corresponding to a value of an HARQ-ACK feedback timing parameter (K1) set in a sub-slot level. Each of bits configuring the HARQ-ACK codebook corresponds to at least one of multiple sub-slots included in the slot.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] Following the commercialization of 4G (4th generation) communication systems, efforts are underway to develop new 5G (5th generation) communication systems to meet the increasing demand for wireless data traffic. 5G communication systems are also referred to as communication systems beyond 4G networks, post-LTE systems, or new radio (NR) systems. To achieve high data rates, 5G communication systems include systems operating using ultra-high frequency (mmWave) bands above 6 GHz, and communication systems operating using frequency bands below 6 GHz to ensure coverage, and implementation of these systems in base stations and terminals is being considered.

[0003] The 3GPP (3rd Generation Partnership Project) NR system improves network spectrum efficiency, enabling carriers to provide more data and voice services within 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 high-capacity voice. The advantages of the NR system include high throughput, low latency, support for frequency division duplex (FDD) and time division duplex (TDD) on the same platform, an improved end-user experience, and low operating costs due to a simple architecture.

[0004] For more efficient data processing, dynamic TDD in an NR system can use a scheme to vary the number of orthogonal frequency division multiplexing (OFDM) symbols available for uplink and downlink transmission depending on the direction of user data traffic in a cell. For example, when the downlink traffic of a cell is larger than the uplink traffic, the base station can allocate a larger number of downlink OFDM symbols to a slot (or subframe). Information about the slot configuration needs to be transmitted to the terminal.

[0005] To mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, technologies being discussed for 5G communication systems include beamforming, massive multiple input / output (massive MIMO), full dimension multiple input / output (FD-MIMO), array antenna, analog beamforming, hybrid beamforming that combines analog beamforming and digital beamforming, and large scale antenna technologies. In addition, to improve the system network, technological developments are being carried out for the 5G communication system in areas such as advanced small cells, improved 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), moving networks, cooperative communication, coordinated multi-points (CoMP), and interference cancellation.Other advanced coding modulation (ACM) methods being developed for 5G systems include hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), as well as advanced access technologies such as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).

[0006] Meanwhile, the Internet, a human-centered network where humans generate and consume information, is evolving into the IoT (Internet of Things) network, which exchanges and processes information among distributed components such as objects. IoE (Internet of Everything) technology, which combines big data processing technology through connections with cloud servers, is also emerging. To realize the IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, research has focused on sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) technologies for connecting objects. In an IoT environment, intelligent IT (internet technology) services are provided that collect and analyze data generated by connected objects and create new value in human life. Through the integration and convergence of traditional IT technology and various industries, the IoT is being applied to areas such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services.

[0007] Therefore, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine, and MTC are being implemented using 5G communication technologies such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN), the big data processing technology mentioned above, is also an example of the fusion of 5G and IoT technologies. Generally, mobile communication systems were developed to provide voice services while ensuring user activity.

[0008] The mobile communication system has gradually expanded its scope from voice to data services, and has now developed to the point where it can provide high-speed data services. However, due to resource shortages in the currently available mobile communication systems and users' demands for high-speed services, a more advanced mobile communication system is desired. Summary of the Invention [Problem to be solved by the invention]

[0009] An object of one embodiment of the present invention is to provide a method and apparatus for efficiently generating a HARQ-ACK codebook in a wireless communication system. [Means for solving the problem]

[0010] According to one aspect of the present invention for achieving the above object, a terminal 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 including one or more bits that indicate whether a channel or a signal has been successfully received, and transmits the HARQ-ACK codebook to a base station of the wireless communication system, wherein the HARQ-ACK codebook is generated based on a slot corresponding to a HARQ-ACK feedback timing parameter (K1) value set at a sub-slot level, and each bit constituting the HARQ-ACK codebook may correspond to at least one sub-slot among a plurality of sub-slots included in the slot.

[0011] The processor may convert the K1 value set at the subslot level into a K1 value set at the slot level, and the slot may be determined as the slot-level HARQ-ACK feedback timing value.

[0012] The K1 value set at the sub-slot level is calculated by the following equation: 1,k,slot is converted to K 1,k is the K1 value set at the sub-slot level, k is the index of the K1 value set at the sub-slot level, K 1,k,slot is the K1 value set at the slot level, n U is the index of the sub-slot in which the PUCCH (physical uplink control channel) is transmitted, N is the number of sub-slots in the slot,

number

[0013]

number

[0014] The processor 1,k,slot can be used to determine the validity of at least one PDSCH (physical downlink shared channel) candidate for an individual slot.

[0015] The processor may determine the at least one PDSCH candidate by a start and length indicator value (SLIV) and determine validity of the dedicated PDSCH candidate.

[0016] The processor 1,k The validity of the PDSCH candidates of the corresponding downlink slots can be determined in descending order of the PDSCH candidates.

[0017] The processor may determine the validity of each of the at least one physical downlink shared channel (PDSCH) candidate based on whether the last symbol is included in a first subslot.

[0018] (i) It can be determined that the PDSCH (physical downlink shared channel) candidate is valid when its last symbol is included in the first subslot, and (ii) it can be determined that the PDSCH (physical downlink shared channel) candidate is invalid when its last symbol is not included in the first subslot.

[0019] The first sub-slot is the sub-slot (n U ) to the K1 value (K 1,k ) may be the sub-slot corresponding to the value obtained by subtracting

[0020] When there is no capability to receive a plurality of PDSCHs in one slot, the processor 1,k For the first downlink slot corresponding to , one HARQ-ACK bit may be included in the HARQ-ACK codebook.

[0021] In the first downlink slot, when a first PDSCH candidate and a second PDSCH candidate following the first PDSCH candidate are valid PDSCH candidates, it may be determined that the HARQ-ACK bit for the second PDSCH candidate is not included in the HARQ-ACK codebook, corresponding to the HARQ-ACK bit for the first downlink slot being included in the HARQ-ACK codebook by the first PDSCH candidate.

[0022] When the processor receives a PDSCH from either the first PDSCH candidate or the second PDSCH candidate, it can transmit HARQ-ACK information of the PDSCH using a HARQ-ACK bit at a position corresponding to the first downlink slot in the HARQ-ACK codebook.

[0023] The processor may calculate K1 values ​​set at all subslot levels corresponding to the K1 value converted to the slot level, and determine the validity of at least one PDSCH candidate based on the calculated K1 values ​​set at all subslot levels.

[0024] The processor may calculate a set of K1 values ​​at a slot level based on a set of K1 values ​​set at a plurality of subslot levels, determine the validity of the at least one PDSCH candidate for a corresponding downlink slot in descending order of the K1 values ​​set at the slot level in the calculated set of K1 values ​​set at the slot level, and generate the HARQ-ACK codebook.

[0025] The processor may (i) determine the validity of PDSCH candidates for a downlink slot corresponding to a first slot level K1 value, and (ii) subsequently determine the validity of PDSCH candidates for a DL slot corresponding to a second slot level K1 value that is smaller than the first slot level K1 value.

[0026] The processor can determine the validity of the first PDSCH candidate based on whether the last symbol of the first PDSCH candidate in the first downlink slot corresponding to the first slot level K1 value is included in the second subslot calculated using the first slot level K1 value.

[0027] The processor may determine that the PDSCH candidate is valid when the last symbol of the PDSCH candidate is included in at least one of the second subslots, and may determine that the PDSCH candidate is invalid when the last symbol of the PDSCH candidate is not included in any of the second subslots.

[0028] The second sub-slot is a sub-slot (n U ) minus a K1 value set at at least one sub-slot level corresponding to the first slot level K1 value.

[0029] The HARQ-ACK codebook may be a semi-static HARQ-ACK codebook in which the number of bits of the HARQ-ACK codebook and whether each bit of the HARQ-ACK codebook indicates whether a channel or signal can be received are set based on RRC (radio resource control) signaling.

[0030] According to another aspect of the present invention for achieving the above object, a method for operating a terminal in a wireless communication system includes: generating a hybrid automatic repeat request (HARQ)-ACK codebook including one or more bits indicating whether a channel or a signal has been successfully received; and transmitting the HARQ-ACK codebook to a base station of the wireless communication system, wherein the generating the HARQ-ACK codebook may include generating the HARQ-ACK codebook based on a slot corresponding to a HARQ-ACK feedback timing parameter (K1) value set at a sub-slot level.

[0031] The step of generating the HARQ-ACK codebook may include converting a HARQ-ACK feedback timing parameter (K1) value set at a subslot level into a slot-level HARQ-ACK feedback timing value, and determining the slot as the slot-level HARQ-ACK feedback timing value.

[0032] The step of generating the HARQ-ACK codebook may be performed by using the K1 value (K 1,k,slot ) for determining the validity of at least one physical downlink shared channel (PDSCH) candidate for an individual slot.

[0033] The step of generating the HARQ-ACK codebook may include determining, for each of the at least one PDSCH (physical downlink shared channel) candidate, validity of the at least one PDSCH candidate based on whether a last symbol is included in a first subslot. [Effects of the Invention]

[0034] According to an embodiment of the present invention, a terminal can transmit a PUCCH including two or more HARQ-ACKs in one slot, which has the effect of increasing the coverage of the PUCCH by reducing the number of HARQ-ACKs that each PUCCH may have. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a diagram illustrating an example of a radio frame structure used in a wireless communication system. [Figure 2] 1 is a diagram illustrating an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. [Figure 3] This figure explains physical channels used in a 3GPP system (e.g., NR) and a general signal transmission method using the corresponding physical channels. [Figure 4a] FIG. 1 illustrates an SS / PBCH block for initial cell access in a 3GPP NR system. [Figure 4b] FIG. 1 illustrates an SS / PBCH block for initial cell access in a 3GPP NR system. [Figure 5a] FIG. 1 illustrates a procedure for control information and control channel transmission in a 3GPP NR system. [Figure 5b] FIG. 1 illustrates a procedure for control information and control channel transmission in a 3GPP NR system. [Figure 6] A diagram showing a CORESET in which PDCCH is transmitted in a 3GPP NR system. [Figure 7] A diagram showing a method for setting a PDCCH search space in a 3GPP NR system. [Figure 8] FIG. 1 is a conceptual diagram illustrating carrier aggregation. [Figure 9] FIG. 1 is a diagram for explaining terminal carrier communication and multi-carrier communication. [Figure 10] A diagram showing an example in which a cross-carrier scheduling technique is applied. [Figure 11]2A and 2B are block diagrams showing the configurations of a terminal and a base station according to an embodiment of the present invention. [Figure 12] FIG. 1 is a diagram showing a procedure for generating a semi-static HARQ-ACK codebook according to one embodiment of the present invention. [Figure 13] 10 is a diagram illustrating a method for transmitting a PUCCH using a PDSCH group indicator according to one embodiment of the present invention. [Figure 14] 10 is a diagram showing a situation in which a collision occurs when transmitting a PUCCH according to a PDSCH group indicator according to one embodiment of the present invention. [Figure 15] 10 is a diagram illustrating a method for transmitting a PUCCH when the unit of K1 is a half slot according to one embodiment of the present invention. FIG. [Figure 16] 10 is a diagram showing a situation in which a collision occurs when transmitting a PUCCH when the unit of K1 in one embodiment of the present invention is a half slot. FIG. [Figure 17] A diagram showing a method of transmitting a PUCCH using a HARQ-ACK multiplexing indicator according to one embodiment of the present invention. [Figure 18(a)] 10 is a diagram illustrating a HARQ-ACK multiplexing method using PRI when transmitting PUCCH according to a HARQ-ACK multiplexing indicator according to one embodiment of the present invention. [Figure 18(b)] 10 is a diagram illustrating a HARQ-ACK multiplexing method using PRI when transmitting PUCCH according to a HARQ-ACK multiplexing indicator according to one embodiment of the present invention. [Figure 19] A diagram showing a method of transmitting PUCCH when there are no K1 and PRI fields in one embodiment of the present invention. [Figure 20]FIG. 10 is a diagram showing a state in which PDSCH candidates are set in slots. [Figure 21] 10 is a diagram illustrating a process of excluding overlapping PDSCH candidates according to one embodiment of the present invention. [Figure 22] FIG. 2 is a diagram illustrating a process for generating a type-1 HARQ-ACK according to one embodiment of the present invention. [Figure 23] FIG. 2 is a diagram illustrating a process for generating a type-1 HARQ-ACK according to one embodiment of the present invention. [Figure 24] 1 is a diagram illustrating a method for configuring a PDSCH candidate and a DL association set (or a PDSCH candidate set) when receiving a PDSCH according to an embodiment of the present invention. [Figure 25] A diagram showing a method for reducing HARQ-ACK size according to one embodiment of the present invention. [Figure 26] A diagram showing a method for reducing HARQ-ACK size according to one embodiment of the present invention. [Figure 27] A diagram showing a method for reducing HARQ-ACK size according to one embodiment of the present invention. [Figure 28(a)] FIG. 10 is a diagram illustrating a method for reducing the HARQ-ACK size in a carrier aggregation situation according to one embodiment of the present invention. [Figure 28(b)] FIG. 10 is a diagram illustrating a method for reducing the HARQ-ACK size in a carrier aggregation situation according to one embodiment of the present invention. [Figure 28(c)] FIG. 10 is a diagram illustrating a method for reducing the HARQ-ACK size in a carrier aggregation situation according to one embodiment of the present invention. [Figure 28(d)] FIG. 10 is a diagram illustrating a method for reducing the HARQ-ACK size in a carrier aggregation situation according to one embodiment of the present invention. [Figure 29] A diagram showing a method for reducing HARQ-ACK size in a carrier aggregation situation according to one embodiment of the present invention. [Figure 30]A diagram showing a method for reducing the HARQ-ACK size within a certain slot according to one embodiment of the present invention. [Figure 31] A diagram showing a method for reducing the HARQ-ACK size within a certain slot according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0036] The terms used in this specification are generally used as widely as possible, taking into consideration the functions of the present invention. However, these may vary depending on the intentions of those skilled in the art, practice, or the emergence of new technologies. In addition, in certain cases, the applicant may arbitrarily select terms. In such cases, the meaning of the terms will be described in the description of the relevant invention. Therefore, it is clear that the terms used in this specification should be interpreted based on the substantive meaning of the terms and the overall content of this specification, rather than simply the names of the terms.

[0037] Throughout this specification, when a component is said to be "connected" to another component, this includes not only "directly connected" but also "electrically connected" through other components in between. Furthermore, when a component is said to "comprise" a specific component, this does not mean excluding the other component, but also means including the other component, unless otherwise specified to the contrary. In addition, limitations such as "more than" or "less than" based on a specific threshold may be appropriately replaced with "more than" or "less than," respectively, depending on the embodiment.

[0038] The following technologies are used in various wireless access systems, such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA is implemented in radio technologies such as UTRA (Universal Terrestrial Radio Access) and CDMA2000. TDMA is implemented in radio technologies such as GSM (Global System for Mobile communications), GPRS (General Packet Radio Service), and EDGE (Enhanced Data Rates for GSM Evolution). OFDMA is implemented in radio technologies such as IEEE802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802-20, and E-UTRA (Evolved UTRA). UTRA is part of UMTS (Universal Mobile Telecommunications System). 3GPP LTE (Long term evolution) is a part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-Advanced (LTE-A) is an evolved version of 3GPP LTE. 3GPP NR is a system designed separately from LTE / LTE-A and is a system for supporting eMBB (enhanced Mobile Broadband), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive Machine Type Communication) services, which are requirements of IMT-2020. For clarity, the following description will focus on 3GPP NR, but the technical concept of the present invention is not limited thereto.

[0039] Unless otherwise specified herein, the base station may include a next generation node B (gNB) defined in 3GPP NR. Also, unless otherwise specified, the terminal may include a user equipment (UE). Hereinafter, to facilitate understanding of the description, each content will be described as a separate embodiment, but each embodiment may be used in combination with each other. In this disclosure, "configuring" a terminal may mean configuration by a base station. Specifically, the base station may transmit a channel or a signal to the terminal to configure the operation of the terminal or parameter values ​​used in the wireless communication system.

[0040] FIG. 1 is a diagram illustrating an example of a radio frame structure used in a radio communication system.

[0041] Referring to FIG. 1, a radio frame used in a 3GPP NR system has a length of 10 ms (ΔfmaxNf / 100)*Tc). Each radio frame consists of 10 equally sized subframes (SF). Here, Δfmax=480*103 Hz, Nf=4096, Tc=1 / (Δfref*Nf,ref), Δfref=15*103 Hz, and Nf,ref=2048. The 10 subframes in a frame are numbered 0 to 9. Each subframe has a length of 1 ms and consists of one or more slots depending on the subcarrier spacing. More specifically, the subcarrier spacing that can be used in a 3GPP NR system is 15*2 μkHz. μ is the subcarrier spacing configuration factor and has values ​​from 0 to 4. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 240 kHz is used as the subcarrier spacing. A 1 ms long subframe consists of 2μ slots, each of which is 2-μms long. The 2μ slots in one subframe are numbered from 0 to 2μ-1. The slots in one radio frame are numbered from 0 to 10*2μ-1. Time resources are divided by at least one of the radio frame number (also called radio frame index), subframe number (also called subframe index), and slot number (or slot index).

[0042] 2 is a diagram illustrating an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system, particularly illustrating a resource grid structure in a 3GPP NR system.

[0043] There is one resource grid per antenna port. Referring to Figure 2, a slot includes multiple OFDM symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. An OFDM symbol also refers to one symbol interval. Unless otherwise specified, an OFDM symbol is simply referred to as a symbol. Hereinafter, in this specification, a symbol includes an OFDM symbol, an SC-FDMA symbol, a DFTs-OFDM symbol, etc. Referring to Figure 2, the signal transmitted from each slot is represented by a resource lattice consisting of Nsize, μgrid, x*NRBSC subcarriers, and Nslotsymb OFDM symbols. Here, x=DL for the downlink resource lattice and x=UL for the uplink resource lattice. Nsize, μgrid, and x represent the number of resource blocks (RBs) according to the subcarrier spacing factor μ (x is DL or UL), and Nslotsymb represents the number of OFDM symbols in a slot. NRBSC is the number of subcarriers constituting one RB, and NRBSC=12. Depending on the multiple access method, the OFDM symbol is called a cyclic prefix OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-S-OFDM) symbol.

[0044] The number of OFDM symbols included in one slot may vary depending on the length of the cyclic prefix (CP). For example, a normal CP includes 14 OFDM symbols, while an extended CP includes 12 OFDM symbols. In a specific embodiment, the extended CP is used only with a subcarrier spacing of 60 kHz. For convenience of explanation, FIG. 2 illustrates a case where one slot includes 14 OFDM symbols. However, the present invention is equally applicable to slots having other numbers of OFDM symbols. Referring to FIG. 2, each OFDM symbol includes Nsize, μgrid, and x*NRBSC subcarriers in the frequency domain. Subcarriers are classified into data subcarriers for transmitting data, reference signal subcarriers for transmitting reference signals, and guard bands. The carrier frequency is also called the center frequency (fc).

[0045] One RB is defined by NRBSC (e.g., 12) consecutive subcarriers in the frequency domain. Incidentally, a resource consisting of one OFDM symbol and one subcarrier is called a resource element (RE) or tone. Therefore, one RB consists of Nslotsymb*NRBSC resource elements. Each resource element in the resource grid is uniquely defined by an index pair (k, l) within one slot. k is an index ranging from 0 to Nsize, μgrid, x*NRBSC-1 in the frequency domain, and l is an index ranging from 0 to Nslotsymb-1 in the time domain.

[0046] In order for a terminal to receive a signal from a base station or transmit a base station signal, the time / frequency synchronization of the terminal must be aligned with the time / frequency synchronization of the base station, because if the base station and the terminal are not synchronized, the terminal cannot determine the time and frequency parameters required to demodulate DL signals and transmit UL signals at the correct time.

[0047] Each symbol in a radio frame operating in time division duplex (TDD) or unpaired spectrum consists of at least one of a downlink symbol (DL symbol), an uplink symbol (UL symbol), or a flexible symbol. A radio frame operating on a downlink carrier in frequency division duplex (FDD) or paired spectrum consists of downlink symbols or flexible symbols, and a radio frame operating on an uplink carrier consists of uplink symbols or flexible symbols. A downlink symbol allows downlink transmission but not uplink transmission, and an uplink symbol allows uplink transmission but not downlink transmission. Whether a flexible symbol is used for downlink or uplink is determined depending on the signal.

[0048] Information about the type of each symbol, i.e., information indicating any one of downlink symbols, uplink symbols, and flexible symbols, is formed by a cell-specific (or common) RRC signal. The information about each symbol type is further formed by a UE-specific (or dedicated) RRC signal. The base station uses the cell-specific RRC signal to notify i) the period of the cell-specific slot configuration, ii) the number of slots having only downlink symbols from the beginning of the cell-specific slot configuration period, iii) the number of downlink symbols from the first symbol of the slot immediately following the slot having only downlink symbols, iv) the number of slots having only uplink symbols from the end of the cell-specific slot configuration period, and v) the number of uplink symbols from the last symbol of the slot immediately preceding the slot having only uplink symbols. Here, symbols that are not configured as either uplink or downlink symbols are flexible symbols.

[0049] If the information regarding the symbol type consists of the per-terminal RRC signal, the base station signals, via the cell-specific RRC signal, whether the flexible symbol is a downlink symbol or an uplink symbol. At this time, the per-terminal RRC signal cannot change a downlink symbol or an uplink symbol that consists of the cell-specific RRC signal to another symbol type. The per-terminal RRC signal signals, for each slot, the number of downlink symbols among the Nslotsymb symbols of the corresponding slot and the number of uplink symbols among the Nslotsymb symbols of the corresponding slot. At this time, the downlink symbols of a slot are continuously configured from the first symbol to the i-th symbol of the slot. Also, the uplink symbols of a slot are continuously configured from the j-th symbol to the last symbol of the slot (where i < j). In a slot, a symbol that is not configured as either an uplink symbol or a downlink symbol is a flexible symbol.

[0050] The type of symbol configured by the RRC signal as described above can be called a semi-static DL / UL configuration. In the semi-static DL / UL configuration configured by the RRC signal, a flexible symbol may be indicated as a downlink symbol, an uplink symbol, or a flexible symbol by the dynamic SFI (slot format information) transmitted on the physical downlink control channel (PDCCH). At this time, a downlink symbol or an uplink symbol configured by the RRC signal is not changed to another symbol type. Table 1 exemplifies the dynamic SFI that the base station can indicate to the terminal.

[0051]

Table 1

[0052] In Table 1, D represents a downlink symbol, U represents an uplink symbol, and X represents a flexible symbol. As shown in Table 1, up to two DL / UL switchings may be allowed within one slot.

[0053] FIG. 3 is a diagram illustrating physical channels used in a 3GPP system (e.g., NR) and a general signal transmission method using the physical channels.

[0054] When a terminal is powered on or newly enters a cell, the terminal performs an initial cell search (S101). Specifically, the terminal synchronizes with a base station during the initial cell search. To do this, the terminal receives a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station and acquire information such as a cell ID. Next, the terminal receives a physical broadcast channel from the base station to acquire broadcast information within the cell.

[0055] After completing the initial cell search, the terminal receives a physical downlink shared channel (PDSCH) via a physical downlink control channel (PDCCH) and information carried on the PDCCH, thereby acquiring more detailed system information than the system information acquired through the initial cell search (S102). Here, the system information transmitted to the terminal is cell-common system information for the terminal to operate correctly in a physical layer in Radio Resource Control (RRC), and is called remaining system information or system information block (SIB) 1.

[0056] When a terminal first connects to a base station or when there are no radio resources for signal transmission (when the terminal is in RRC_IDLE mode), the terminal can perform a random access procedure with the base station (steps S103 to S106). First, the terminal transmits a preamble on a physical random access channel (PRACH) (S103) and can receive a response message for the preamble from the base station on a PDCCH and a corresponding PDSCH (S104). If the terminal receives a valid random access response message, the terminal transmits data including its own identifier, etc. to the base station on a physical uplink shared channel (PUSCH) indicated by an uplink grant transmitted from the base station on the PDCCH (S105). Next, the terminal waits for reception of a PDCCH as instructed by the base station to resolve collisions. If the terminal successfully receives the PDCCH with its own identifier (S106), the random access procedure ends. During the random access procedure, the terminal can acquire terminal-specific system information required for the terminal to operate correctly in the physical layer of the RRC layer. If the terminal acquires the terminal-specific system information in the RRC layer, the terminal enters the RRC connected mode (RRC_CONNECTED mode).

[0057] The RRC layer is used to generate and manage messages for control between a terminal and a radio access network (RAN). Furthermore, the base station and terminal can broadcast cell system information required for all terminals in the cell, manage paging message transmission, manage mobility and handover, report terminal measurements and related control, and manage and store terminal capabilities at the RRC layer. Generally, the update of signals transmitted at the RRC layer (hereinafter referred to as RRC signals) is longer than the transmission / reception period (i.e., transmission time interval, TTI) at the physical layer, so that the RRC configuration can be maintained unchanged for a long period.

[0058] After the above procedures, the UE receives the PDCCH / PDSCH (S107) and transmits the physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) (S108) as a general uplink / downlink signal transmission procedure. In particular, the UE receives downlink control information (DCI) via the PDCCH. The DCI includes control information such as resource allocation information for the UE. The format of the DCI may vary depending on the purpose of use. The uplink control information (UCI) transmitted by the UE to the base station via the uplink includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), a rank indicator (RI), etc. Here, the CQI, PMI, and RI are included in channel state information (CSI). In the case of a 3GPP NR system, the UE transmits control information such as the above-mentioned HARQ-ACK and CSI via the PUSCH and / or PUCCH.

[0059] 4A and 4B show a synchronization signal (SS) / physical broadcast channel (PBCH) block for initial cell connection in a 3GPP NR system. When a terminal is powered on or attempts to access a new cell, it acquires time and frequency synchronization with the cell and performs an initial cell search process. During the cell search process, the terminal detects the physical cell identity (NcellID) of the cell. To this end, the terminal receives synchronization signals, such as a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), from the base station to synchronize with the base station. At this time, the terminal acquires information such as a cell identity (ID).

[0060] The synchronization signal (SS) will be described in more detail with reference to Figures 4A and 4B. The synchronization signal is divided into a PSS and an SSS. The PSS is used to obtain time domain synchronization and / or frequency domain synchronization, such as OFDM symbol synchronization and slot synchronization. The SSS is used to obtain frame synchronization and a cell group ID. Referring to Figure 4(a) and Table 1, an SS / PBCH block consists of 20 consecutive RBs (=240 subcarriers) on the frequency axis and 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 via subcarriers 56 to 182. Here, the lowest subcarrier index in the SS / PBCH block starts from 0. In the first OFDM symbol in which the PSS is transmitted, the base station does not transmit signals via the remaining subcarriers, i.e., subcarriers 0 to 55 and 183 to 239. In addition, in the third OFDM symbol in which the SSS is transmitted, the base station does not transmit signals via subcarriers 48 to 55 and 183 to 191. In the SS / PBCH block, the base station transmits PBCH signals via the remaining REs excluding the above signals.

[0061] [Table 2]

[0062] The SS groups a total of 1008 unique physical layer cell IDs (physical layer cell IDs) into 336 physical layer cell ID groups, each containing three unique identifiers, through the combination of three PSSs and SSSs. Specifically, each physical layer cell ID is part of only one physical layer cell ID group. Thus, the physical layer cell ID NcellID = 3N(1)ID + N(2)ID is uniquely defined by an index N(1)ID ranging from 0 to 335 indicating a physical layer cell ID group and an index N(2)ID ranging from 0 to 2 indicating a physical layer identifier within the physical layer cell ID group. The UE detects the PSS and identifies one of the three unique physical layer identifiers. The UE also detects the SSS and identifies one of the 336 physical layer cell IDs associated with the physical layer identifier. In this case, the PSS sequence dPSS(n) is as follows:

[0063] d PSS (n)=1-2x(m)

[0064] m=(n+43N (2 ) ID ) mod 127

[0065] 0≦n<127

[0066] where x(i+7)=(x(i+4)+x(i)) mod 2,

[0067] Given that [x(6)x(5)x(4)x(3)x(2)x(1)x(0)]=[1110110].

[0068] Also, the sequence of SSS SSS (n) is as follows:

[0069] d SSS (n)=[1-2x0((n+m0) mod 127][1-2x i ((n+m1) mod 127]

[0070] m0=15 floor(N( 1 ) ID / 112)+5N( 2 ) ID

[0071] m1=N( 1 ) ID mod 112

[0072] 0≦n<127

[0073] where x0(i+7)=(x0(i+4)+x0(i))mod 2

[0074] x1(i+7)=(x1(i+1)+x1(i))mod 2,

[0075] [x0(6)x0(5)x0(4)x0(3)x0(2)x0(1)x0(0)]=[0000001]

[0076] Given that [x1(6)x1(5)x1(4)x1(3)x1(2)x1(1)x1(0)]=[0000001].

[0077] A 10-ms radio frame is divided into two 5-ms half-frames. Referring to FIG. 4(b), the slot in which the SS / PBCH block is transmitted within each half-frame is described. The slot in which the SS / PBCH block is transmitted is one of Cases A, B, C, D, and E. In Case A, the subcarrier spacing is 15 kHz, and the start point of the SS / PBCH block is the {2, 8} + 14*n symbol. Here, n = 0 or 1 for carrier frequencies below 3 GHz. Also, n = 0, 1, 2, or 3 for carrier frequencies above 3 GHz and below 6 GHz. In Case B, the subcarrier spacing is 30 kHz, and the start point of the SS / PBCH block is the {4, 8, 16, 20} + 28*n symbol. Here, n = 0 for carrier frequencies below 3 GHz. Also, n = 0 or 1 for carrier frequencies above 3 GHz and below 6 GHz. In Case C, the subcarrier spacing is 30 kHz and the start of the SS / PBCH block is at the {2,8}+14*n symbol, where n=0, 1 for carrier frequencies below 3 GHz. For carrier frequencies above 3 GHz and below 6 GHz, n=0, 1, 2, 3. In Case D, the subcarrier spacing is 120 kHz and the start of the SS / PBCH block is at the {4,8,16,20}+28*n symbol, where n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18 for carrier frequencies above 6 GHz. In Case E, the subcarrier spacing is 240 kHz and the start of the SS / PBCH block is at the {8,12,16,20,32,36,40,44}+56*n symbol. In this case, n=0, 1, 2, 3, 5, 6, 7, 8 for carrier frequencies above 6 GHz.

[0078] 5 is a diagram showing a procedure for transmitting control information and a control channel in a 3GPP NR system. Referring to FIG. 5(a), a base station adds a cyclic redundancy check (CRC) masked (e.g., XORed) with a radio network temporary identifier (RNTI) to control information (e.g., DCI) S202. The base station scrambles the CRC with an RNTI value determined according to the purpose / target of each control information. The common RNTI used by one or more terminals includes 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). The UE-specific RNTI includes at least one of a cell temporary RNTI (C-RNTI), a CS-RNTI, or an MCS-C-RNTI. Next, the base station performs channel encoding (e.g., polar coding) S204 and then rate-matching S206 according to the amount of resource(s) used for PDCCH transmission. Next, the base station multiplexes DCI(s) based on a CCE (control channel element)-based PDCCH structure S208. The base station then applies additional processes S210, such as scrambling, modulation (e.g., QPSK), and interleaving, to the multiplexed DCI(s) and maps them to resources to be transmitted. A CCE is the basic resource unit for the PDCCH, and one CCE consists of multiple (e.g., six) resource element groups (REGs). One REG consists of multiple (e.g., 12) REs. The number of CCEs used for one PDCCH is defined as the aggregation level. 3GPP NR systems use aggregation levels of 1, 2, 4, 8, or 16.FIG. 5(b) is a diagram relating to CCE aggregation levels and PDCCH multiplexing, showing the types of CCE aggregation levels used for one PDCCH and the CCE(s) transmitted in the control region accordingly.

[0079] FIG. 6 is a diagram showing a CORESET in which a PDCCH is transmitted in a 3GPP NR system.

[0080] A CORESET is a time-frequency resource over which a PDCCH, a control signal for a terminal, is transmitted. A search space, which will be described later, is mapped to one CORESET. Therefore, a terminal does not monitor all frequency bands to receive a PDCCH, but rather monitors a time-frequency region designated as a CORESET and decodes the PDCCH mapped to the CORESET. A base station configures one or more CORESETs for each cell of a terminal. A CORESET consists of up to three consecutive symbols on the time axis. A CORESET also consists of six consecutive PRBs on the frequency axis. In the embodiment of FIG. 5, CORESET#1 consists of consecutive PRBs, and CORESET#2 and CORESET#3 consist of non-consecutive PRBs. A CORESET can be located at any symbol within a slot. For example, in the embodiment of FIG. 5, CORESET#1 starts from the first symbol of the slot, CORESET#2 starts from the fifth symbol of the slot, and CORESET#9 starts from the ninth symbol of the slot.

[0081] FIG. 7 is a diagram illustrating a method for configuring a PDCCH search space in a 3GPP NR system.

[0082] At least one search space exists in each CORESET for transmitting a PDCCH to a UE. In an embodiment of the present invention, the search space is a set of all time-frequency resources (hereinafter referred to as PDCCH candidates) on which the PDCCH of the UE is transmitted. The search space includes a common search space that 3GPP NR UEs should commonly search and a terminal-specific or UE-specific search space that a specific UE should search. In the common search space, all UEs in a cell belonging to the same base station monitor a PDCCH that is configured to be commonly searched. In addition, the UE-specific search space is configured for each UE so that the UE monitors the PDCCH allocated to each UE at different search space positions depending on the UE. In the case of a UE-specific search space, the search spaces allocated to UEs may partially overlap due to the limited control region to which the PDCCH is allocated. Monitoring the PDCCH includes blind decoding of PDCCH candidates in the search space. If blind decoding is successful, it is expressed as the PDCCH being (successfully) detected / received, and if blind decoding fails, it is expressed as the PDCCH being undetected / unreceived or not being successfully detected / received.

[0083] For convenience of explanation, a PDCCH scrambled with a group common (GC) RNTI already known by one or more terminals to transmit downlink control information to one or more terminals is referred to as a group common (GC) PDCCH or a common PDCCH. Also, a PDCCH scrambled with a terminal-specific RNTI already known by a specific terminal to transmit uplink scheduling information or downlink scheduling information to one specific terminal is referred to as a terminal-specific PDCCH. The common PDCCH is included in a common search space, and the terminal-specific PDCCH is included in the common search space or the terminal-specific PDCCH.

[0084] A base station notifies each terminal or a terminal group of information regarding resource allocation of transmission channels, i.e., DL Grant, for the paging channel (PCH) and downlink-shared channel (DL-SCH), or information regarding resource allocation of the UL-SCH and hybrid automatic repeat request (HARQ) (i.e., UL Grant), via a PDCCH. The base station transmits PCH transport blocks and DL-SCH transport blocks via a PDSCH. The base station transmits data excluding specific control information or specific service data via the PDSCH. In addition, terminals receive data excluding specific control information or specific service data via the PDSCH.

[0085] The base station transmits information on which terminal (one or more terminals) the PDSCH data is transmitted to and how the terminal should receive and decode the PDSCH data, by including the information in the PDCCH. For example, assume that DCI transmitted over 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 location), and indicates transmission format information "C" (e.g., transmission block size, modulation scheme, coding information, etc.). The terminal monitors the PDCCH using its own RNTI information. In this case, if there is a terminal that blind decodes the PDCCH using RNTI "A," the terminal receives the PDCCH and receives the PDSCH indicated by "B" and "C" through the received PDCCH information.

[0086] Table 3 shows an example of a PUCCH used in a wireless communication system.

[0087] [Table 3]

[0088] The PUCCH is used to transmit the following uplink control information (UCI):

[0089] - SR (Scheduling Request): Information used to request uplink UL-SCH resources.

[0090] HARQ-ACK: A response to a PDCCH (indicating DL SPS release) and / or a response to an uplink transport block (TB) on a PDSCH. HARQ-ACK indicates whether information transmitted via a PDCCH or a PDSCH has been received. HARQ-ACK responses include a positive ACK (simply referred to as ACK), a negative ACK (hereinafter referred to as NACK), DTX (Discontinuous Transmission), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK / NACK and ACK / NACK. Generally, ACK is represented by a bit value of 1, and NACK is represented by a bit value of 0.

[0091] CSI: Feedback information for the downlink channel. It is generated by the terminal based on the CSI-RS (Reference Signal) transmitted by the base station. MIMO (multiple input multiple output)-related feedback information includes RI and PMI. CSI is divided into CSI part 1 and CSI part 2 according to the information indicated by the CSI.

[0092] In the 3GPP NR system, five PUCCH formats are used to support various service scenarios, various channel environments, and frame structures.

[0093] PUCCH format 0 is a format that transmits 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 is transmitted using one or two OFDM symbols on the time axis and one RB on the frequency axis. If PUCCH format 0 is transmitted using two OFDM symbols, the same sequence is transmitted in two symbols using different RBs. This allows the UE to obtain frequency diversity gain. More specifically, the UE bit Bit UCI(M bit =1 or 2), the cyclic shift value m cs Determine the base sequence of length 12 and set it to a given value m cs The cyclically shifted sequence is mapped to 12 REs of one OFDM symbol and one PRB and transmitted. The number of cyclic shifts available to the terminal is 12, and M bit If =1, 1-bit UCI0 and 1 are represented by a sequence corresponding to two cyclic shifts whose difference in cyclic shift value is 6. Also, M bit = 2, then the 2-bit UCI 00, 01, 11, 10 is represented by a sequence corresponding to four cyclic shifts with a difference of 3 between the cyclic shift values.

[0094] PUCCH format 1 carries 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 is transmitted using consecutive OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 is one of 4 to 14. More specifically, UCI with Mbit=1 is modulated using BPSK. The UE modulates UCI with Mbit=2 using quadrature phase shift keying (QPSK). A signal is obtained by multiplying the modulated complex-valued symbol d(0) with a length 12 sequence. The UE transmits the obtained signal by spreading it with an orthogonal cover code (OCC) on the even-numbered OFDM symbols assigned to PUCCH format 1. In PUCCH format 1, the maximum number of different UEs that can be multiplexed in the same RB is determined depending on the length of the OCC used. In odd-numbered OFDM symbols of PUCCH format 1, a demodulation reference signal (DMRS) is spread by OCC and mapped.

[0095] PUCCH format 2 carries UCI exceeding 2 bits. PUCCH format 2 is transmitted using one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. If PUCCH format 2 is transmitted using two OFDM symbols, the same sequence is transmitted using different RBs across the two OFDM symbols. This allows the UE to obtain frequency diversity gain. More specifically, Mbit UCI (Mbit>2) is bit-level scrambled, QPSK modulated, and mapped to the RBs of one or two OFDM symbols. Here, the number of RBs is one of 1 to 16.

[0096] PUCCH format 3 or PUCCH format 4 transmits UCI exceeding 2 bits. PUCCH format 3 or PUCCH format 4 is transmitted using consecutive OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 is one of 4 to 14. Specifically, the terminal modulates Mbit-bit UCI (Mbit>2) using π / 2-BPSK (Binary Phase Shift Keying) or QPSK to generate complex symbols d(0) to d(Msymb-1). Here, when π / 2-BPSK is used, Msymb=Mbit, and when QPSK is used, Msymb=Mbit / 2. The terminal does not apply block-wise spreading to PUCCH format 3. However, the terminal may apply block-wise spreading to one RB (i.e., 12 subcarriers) using a PreDFT-OCC of length -12 so that PUCCH format 4 has a multiplexing capacity of 2 or 4. The terminal transmit precoding (or DFT-precoding) the spreaded signal, maps it to each RE, and transmits the spreaded signal.

[0097] In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 is determined according to the length of UCI transmitted by the terminal and the maximum code rate. If the terminal uses PUCCH format 2, the terminal transmits both HARQ-ACK information and CSI information via the PUCCH. If the number of RBs that the terminal can transmit is greater than the maximum number of RBs that PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the terminal does not transmit some UCI information and transmits only the remaining UCI information according to the priority of the UCI information.

[0098] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured via RRC signaling to indicate frequency hopping within a slot. When frequency hopping is configured, the index of the RB to be frequency hopped is configured via RRC signaling. If PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted over N OFDM symbols on the time axis, the first hop has floor(N / 2) OFDM symbols, and the second hop has ceil(N / 2) OFDM symbols.

[0099] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured to be repeatedly transmitted in multiple slots. In this case, the number K of slots in which the PUCCH is repeatedly transmitted is configured by an RRC signal. The repeatedly transmitted PUCCH should start from the same OFDM symbol position in each slot and have the same length. If the RRC signal indicates that any one of the OFDM symbols in a slot in which the UE should transmit the PUCCH is a DL symbol, the UE does not transmit the PUCCH from the corresponding slot but postpones its transmission to the next slot.

[0100] Meanwhile, in a 3GPP NR system, a terminal transmits and receives using a bandwidth smaller than or equal to the bandwidth of a carrier (or cell). To this end, the terminal is configured with a bandwidth part (BWP) consisting of a continuous portion of the carrier bandwidth. A terminal operating according to TDD or using an unpaired spectrum is configured with up to four DL / UL BWP pairs per carrier (or cell). The terminal also activates one DL / UL BWP pair. A terminal operating according to FDD or using a paired spectrum is configured with up to four DL BWPs per downlink carrier (or cell) and up to four UL BWPs per uplink carrier (or cell). The terminal activates one DL BWP and one UL BWP for each carrier (or cell). The terminal may not receive or transmit from time-frequency resources other than the activated BWP. An activated BWP is called an active BWP.

[0101] The base station refers to the activated BWP among the BWPs configured for the UE as a DCI. The BWP indicated in the DCI is activated, and the other configured BWP(s) are deactivated. In a carrier (or cell) operating in TDD, the base station includes a bandwidth part indicator (BPI) indicating the activated BWP in the DCI scheduling the PDSCH or PUSCH to change the DL / UL BWP pair of the UE. The UE receives the DCI scheduling the PDSCH or PUSCH and identifies the activated DL / UL BWP pair based on the BPI. In a downlink carrier (or cell) operating in FDD, the base station includes a BPI indicating the activated BWP in the DCI scheduling the PDSCH to change the DL BWP of the UE. In an uplink carrier (or cell) operating in FDD, the base station includes a BPI indicating the activated BWP in the DCI scheduling the PDSCH to change the UE's UL BWP.

[0102] FIG. 8 is a conceptual diagram illustrating carrier aggregation.

[0103] Carrier aggregation refers to a method in which a mobile station uses multiple frequency blocks or (logical) cells consisting of uplink resources (or component carriers) and / or downlink resources (or component carriers) in one large logical frequency band so that the wireless communication system can use a wider frequency band. For convenience of explanation, the term "component carrier" will be used hereinafter.

[0104] Referring to Figure 8, in an example of a 3GPP NR system, the entire system band includes up to 16 component carriers, each of which has a bandwidth of up to 400 MHz. A component carrier includes one or more physically contiguous subcarriers. While Figure 8 shows each component carrier having the same bandwidth, this is merely an example, and each component carrier may have a different bandwidth. Furthermore, although each component carrier is shown adjacent to each other on the frequency axis, this is shown only as a logical concept, and each component carrier may be physically adjacent to each other or separated from each other.

[0105] A different center frequency is used for each component carrier. Also, a common center frequency is used for physically adjacent component carriers. In the embodiment of Fig. 8, if it is assumed that all component carriers are physically adjacent, center frequency A is used for all component carriers. Also, if it is assumed that the component carriers are not physically adjacent, center frequency A and center frequency B are used for each component carrier.

[0106] When the entire system band is expanded by carrier aggregation, the frequency band used for communication with each terminal is defined in component carrier units. Terminal A uses the entire system band of 100 MHz and communicates using all five component carriers. Terminals B1 to B5 only use a 20 MHz bandwidth and communicate using one component carrier. Terminals C1 and C2 only use a 40 MHz bandwidth and each communicate using two component carriers. The two component carriers may or may not be logically / physically adjacent. The example in Figure 8 shows a case where terminal C1 uses two non-adjacent component carriers and terminal C2 uses two adjacent component carriers.

[0107] 9A and 9B are diagrams for explaining single-carrier communication and multi-carrier communication, in particular, FIG. 9A shows a subframe structure of a single carrier, and FIG. 9B shows a subframe structure of a multi-carrier.

[0108] Referring to FIG. 9(a), in an FDD mode, a typical wireless communication system transmits or receives data through one DL band and one corresponding UL band. In another specific embodiment, in a TDD mode, the wireless communication system divides a radio frame into uplink time units and downlink time units in the time domain, and transmits or receives data through the uplink / downlink time units. Referring to FIG. 9(b), three 20 MHz component carriers (CCs) are aggregated in each of the UL and DL to support a 60 MHz bandwidth. The CCs may be adjacent or non-adjacent to each other in the frequency domain. For convenience, FIG. 9(b) illustrates a case where the bandwidths of the UL CC and the DL CC are the same and symmetrical, but the bandwidths of each CC may be determined independently. Also, asymmetric carrier aggregation, in which the number of UL CCs and the number of DL CCs are different, is possible. The DL / UL CC allocated / configured to a specific terminal via RRC is referred to as the serving DL / UL CC of the specific terminal.

[0109] A base station communicates with a terminal by activating some or all of the serving CCs of the terminal or deactivating some of the CCs. The base station may change the activated / deactivated CCs or the number of activated / deactivated CCs. When a base station allocates CCs available to a terminal in a cell-specific or terminal-specific manner, at least one of the allocated CCs may not be deactivated unless the CC allocation for the terminal is completely reconfigured or the terminal performs a handover. A CC that is not deactivated by the terminal is called a primary CC (PCC) or PCell (primary cell), and a CC that the base station can activate / deactivate freely is called a secondary CC (SCC) or SCell (secondary cell).

[0110] Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of downlink and uplink resources, i.e., a combination of DL CC and UL CC. A cell may consist of only DL resources or a combination of DL and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of DL resources (or DL ​​CC) and the carrier frequency of UL resources (or UL CC) is indicated by system information. Carrier frequency refers to the center frequency of each cell or CC. A cell corresponding to a PCC is called a PCell, and a cell corresponding to an SCC is called an SCell. The carrier corresponding to a PCell in the downlink is a DL PCC, and the carrier corresponding to a PCell in the uplink is a UL PCC. Similarly, the carrier corresponding to an SCell in the downlink is a DL SCC, and the carrier corresponding to an SCell in the uplink is a UL SCC. Depending on the terminal capacity, a serving cell(s) may consist of one PCell and zero or more SCells. For a UE in RRC_CONNECTED state but not configured with carrier aggregation or not supporting carrier aggregation, there is only one serving cell consisting of only a PCell.

[0111] As described above, the term "cell" used in carrier aggregation is different from the term "cell" referring to a certain geographical area where communication services are provided by one base station or one antenna group. However, in order to distinguish between a cell referring to a certain geographical area and a cell of carrier aggregation, in the present invention, a cell of carrier aggregation is referred to as a CC, and a cell of a geographical area is referred to as a cell.

[0112] 10 is a diagram illustrating an example in which a cross-carrier scheduling technique is applied. When cross-carrier scheduling is configured, a control channel transmitted over a first CC schedules a data channel transmitted over a first or second CC using a carrier indicator field (CIF). The CIF is included in the DCI. In other words, a scheduling cell is configured, and a DL grant / UL grant transmitted from the PDCCH region of the scheduling cell schedules the PDSCH / PUSCH of a scheduled cell. That is, the PDCCH region of the scheduling cell is the search space for multiple component carriers. A PCell is basically a scheduling cell, and a specific SCell is designated as the scheduling cell by a higher layer.

[0113] In the embodiment of FIG. 10, it is assumed that three DL CCs are merged. Here, it is assumed that DL component carrier #0 is a DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are DL SCCs (or SCells). It is also assumed that the DL PCCs are configured as PDCCH monitoring CCs. If cross-carrier scheduling is not configured by UE-specific (or UE-group-specific, or cell-specific) higher layer signaling, the CIF is disabled, and each DL CC transmits only a PDCCH scheduling its own PDSCH without a CIF according to the NR PDCCH rules (non-cross-carrier scheduling, self-carrier scheduling). On the other hand, if cross-carrier scheduling is configured by UE-specific (or UE-group-specific, or cell-specific) higher layer signaling, the CIF is enabled, and a specific CC (e.g., DL PCC) transmits not only a PDCCH scheduling the PDSCH of DL CC A but also a PDCCH scheduling the PDSCH of another CC using the CIF (cross-carrier scheduling). In contrast, PDCCH is not transmitted on other DL CCs. Therefore, depending on whether cross-carrier scheduling is configured in the terminal, the terminal monitors the PDCCH without a CIF to receive a self-carrier scheduled PDSCH, or monitors the PDCCH with a CIF to receive a cross-carrier scheduled PDSCH.

[0114] 9 and 10 illustrate the subframe structure of a 3GPP LTE-A system, the same or similar structure can also be applied to a 3GPP NR system, except that in a 3GPP NR system, the subframes in FIGS. 9 and 10 are switched to slots.

[0115] 11 is a block diagram illustrating the configuration of a terminal and a base station according to an embodiment of the present invention. In an embodiment of the present invention, the terminal may be implemented as any of various types of wireless communication devices or computing devices that ensure portability and mobility. The terminal may be referred to as a UE, a station (STA), a mobile subscriber (MS), etc. In addition, in an embodiment of the present invention, the base station controls and manages cells (e.g., macrocells, femtocells, picocells, etc.) corresponding to a service area, and performs functions such as signal transmission, channel assignment, channel monitoring, self-diagnosis, and relaying. The base station may be referred to as a next generation NodeB (gNB) or an access point (AP), etc.

[0116] As shown, a terminal 100 according to one embodiment of the present invention includes a processor 110 , a communication module 120 , a memory 130 , a user interface unit 140 , and a display unit 150 .

[0117] First, the processor 110 executes various commands or programs to process data within the terminal 100. The processor 110 also controls the overall operation of the terminal 100, including each unit, and controls the transmission and reception of data between the units. Here, the processor 110 is configured to perform operations according to the embodiments described in the present invention. For example, the processor 110 may receive slot configuration information, determine the slot configuration based on the information, and perform communication according to the determined slot configuration.

[0118] Next, the communication module 120 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 120 includes multiple network interface cards (NICs) such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123, either built-in or external. Although the communication module 120 is shown as an integrated module in the drawings, the network interface cards may be independently arranged depending on the circuit configuration or application, unlike the drawings.

[0119] The cellular communication interface card 121 transmits and receives wireless signals to and from at least one of the base station 200, an external device, and a server via a mobile communication network, and provides cellular communication services using a first frequency band based on instructions from the processor 110. According to one embodiment, the cellular communication interface card 121 includes at least one NIC module that utilizes a frequency band below 6 GHz. The at least one NIC module of the cellular communication interface card 121 independently performs cellular communication with at least one of the base station 200, the external device, and the server in accordance with a cellular communication standard or protocol for the frequency band below 6 GHz supported by the corresponding NIC module.

[0120] The cellular communication interface card 122 transmits and receives wireless signals to and from at least one of the base station 200, an external device, and a server using a mobile communication network, and provides cellular communication services in the second frequency band based on instructions from the processor 110. According to one embodiment, the cellular communication interface card 122 includes at least one NIC module that uses a frequency band above 6 GHz. The at least one NIC module of the cellular communication interface card 122 independently performs cellular communication with at least one of the base station 200, the external device, and the server in accordance with the cellular communication standard or protocol for the frequency band above 6 GHz supported by the corresponding NIC module.

[0121] The unlicensed band communication interface card 123 transmits and receives wireless signals to and from at least one of the base station 200, an external device, and a server via the third frequency band, which is an unlicensed band, and provides unlicensed band communication services based on instructions from the processor 110. The unlicensed band communication interface card 123 includes at least one NIC module that uses the unlicensed band. For example, the unlicensed band may be the 2.4 GHz or 52.6 GHz band. The at least one NIC module of the unlicensed band communication interface card 123 independently or dependently performs cellular communication with at least one of the base station 200, the external device, and the server according to the unlicensed band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0122] The memory 130 stores control programs and various data used by the terminal 100. The control programs include predetermined programs required for the terminal 100 to perform wireless communication with at least one of the base station 200, an external device, and a server.

[0123] Next, the user interface 140 includes various types of input / output means provided in the terminal 100. That is, the user interface unit 140 receives user input using various input means, and the processor 110 controls the terminal 100 based on the received user input. Also, the user interface 140 performs output based on instructions from the processor 110 using various output means.

[0124] The display unit 150 then outputs various images to a display screen, and displays various display objects such as a user interface based on the content or control instructions of the processor 110.

[0125] The base station 200 according to the embodiment of the present invention also includes a processor 210 , a communication module 220 , and a memory 230 .

[0126] First, the processor 210 executes various instructions or programs to process data within the base station 200. The processor 210 also controls the overall operation of the base station 200, including each unit, and controls the transmission and reception of data between the units. Here, the processor 210 is configured to perform operations according to the embodiments described herein. For example, the processor 210 may signal slot configuration information and perform communication according to the signaled slot configuration.

[0127] Next, the communication module 220 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 220 includes multiple network interface cards, such as cellular communication interface cards 221 and 222 and an unlicensed band communication interface card 223, either built-in or externally mounted. Although the communication module 220 is shown as an integrated module in the drawings, the network interface cards may be independently arranged depending on the circuit configuration or application, unlike the drawings.

[0128] The cellular communication interface card 221 transmits and receives wireless signals to and from at least one of the terminal 100, the external device, and the server using a mobile communication network, and provides a cellular communication service using a first frequency band based on instructions from the processor 210. According to one embodiment, the cellular communication interface card 221 includes at least one NIC module using a frequency band below 6 GHz. The at least one NIC module of the cellular communication interface card 221 independently performs cellular communication with at least one of the terminal 100, the external device, and the server according to a cellular communication standard or protocol for the frequency band below 6 GHz supported by the corresponding NIC module.

[0129] The cellular communication interface card 222 transmits and receives wireless signals to and from at least one of the terminal 100, an external device, and a server using a mobile communication network, and provides cellular communication services in the second frequency band based on instructions from the processor 210. According to one embodiment, the cellular communication interface card 222 includes at least one NIC module that uses a frequency band above 6 GHz. The at least one NIC module of the cellular communication interface card 222 independently performs cellular communication with at least one of the terminal 100, the external device, and the server according to a cellular communication standard or protocol for the frequency band above 6 GHz that the corresponding NIC module supports.

[0130] The unlicensed band communication interface card 223 transmits and receives wireless signals to and from at least one of the terminal 100, an external device, and a server using the third frequency band, which is an unlicensed band, and provides unlicensed band communication services based on instructions from the processor 210. The unlicensed band communication interface card 223 includes at least one NIC module that uses the unlicensed band. For example, the unlicensed band may be the 2.4 GHz or 52.6 GHz band. The at least one NIC module of the unlicensed band communication interface card 223 independently or dependently performs cellular communication with at least one of the terminal 100, an external device, and a server according to the unlicensed band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0131] The terminal 100 and base station 200 shown in Figure 11 are block diagrams according to one embodiment of the present invention, and the separate blocks indicate logically distinct device elements. Therefore, the above-described device elements may be mounted on one chip or multiple chips depending on the device design. In addition, some components of the terminal 100, such as the user interface 150 and the display unit 150, may be selectively provided in the terminal 100. In addition, the user interface 140 and the display unit 150 may be additionally provided in the base station 200 as needed.

[0132] Meanwhile, in relation to the configuration for transmitting HARQ-ACK, the UE can transmit 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 base station can schedule 1TB (Transport Block) or 2TB on a downlink control channel (e.g., PDCCH) for scheduling the PDSCH to the UE. If only 1TB is scheduled, the UE must feed back a 1-bit HARQ-ACK bit of the TB. If 2TB is scheduled, the UE must feed back a 2-bit HARQ-ACK bit for each of the 2TB. To avoid misunderstandings between the base station and the UE, there may be a predetermined order between the 2-bit HARQ-ACK bit and the 2TB. For reference, when the MIMO (Multiple-input Multiple-output) transmission rank or layer is low, 1TB is transmitted, and when the MIMO transmission rank or layer is high, 2TB is transmitted.

[0133] The component carrier described in an embodiment of the present invention may be used synonymously with the term cell. For convenience of explanation, the embodiment of the present invention focuses on carrier aggregation, but in a TDD system using carrier aggregation, the component carrier may be considered to correspond to all component carriers of a subframe (or slot) in which HARQ-ACK multiplexing is performed.

[0134] When a terminal uses carrier aggregation, which aggregates multiple carriers for transmission, each component carrier may be configured with a different transmission scheme. That is, component carrier #0 may be configured for 1TB transmission, and component carrier #1 may be configured for 2TB transmission. When either self-carrier scheduling or cross-carrier scheduling is configured in the terminal, the terminal targets the component carriers that should monitor the PDCCH according to the scheme configured in the terminal, monitors the component carriers, decodes the PDCCH, collects HARQ-ACKs for TBs transmitted via PDSCHs on each component carrier, and transmits them on a PUCCH (or PUSCH). However, the terminal may fail to decode the PDCCHs scheduled on some component carriers configured by the base station (this is considered to be the occurrence of DTX (discontinuous transmission)). As a result, the terminal may collect only the HARQ-ACKs of the remaining component carriers that were successfully decoded, excluding the HARQ-ACK of the component carrier, and transmit them on a PUCCH (or PUSCH). In this case, misunderstanding may occur in the interpretation of the HARQ-ACK feedback between the base station and the terminal.

[0135] To solve this problem, 3GPP NR (New Radio) supports a semi-static HARQ-ACK codebook (type-1 HARQ-ACK codebook) and a dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook).

[0136] FIG. 12 is a diagram illustrating a procedure for generating a semi-static HARQ-ACK codebook according to one embodiment of the present invention.

[0137] As described above, a semi-static HARQ-ACK codebook is a codebook in which a terminal and a base station agree in advance on the length of the HARQ-ACK codebook and which PDSCH each bit represents as ACK / NACK information, and does not require separate signaling. Here, a set of PDSCH candidates included in the semi-static HARQ-ACK codebook is called a DL association set (or a PDSCH candidate set). One embodiment of the present invention relates to a method for determining a DL association set (or a PDSCH candidate set) in a semi-static HARQ-ACK codebook.

[0138] In one embodiment of the present invention, the information used by the UE when determining a DL association set (or a PDSCH candidate set) is as follows. First, the information includes all K1 values ​​that can be instructed to the UE. Here, the K1 value represents the difference between the last slot in which the PDSCH is transmitted (or scheduled) and the slot in which the PUCCH is transmitted. A fallback DCI (or DCI format 1_0) may have one of {1, 2, 3, 4, 5, 6, 7, 8} as the K1 value, and a non-fallback DCI (or DCI format 1_1 or DCI format 1_2) may have up to eight K1 values ​​configured by an RRC signal. Second, the information includes all K0 values ​​that can be instructed to the UE and combinations of the PDSCH start symbol and length within a slot. Here, the PDSCH start symbol and length are jointly encoded and indicated as a start and length indicator value (SLIV). Here, the K0 value represents the difference between the slot in which the PDCCH is transmitted and the slot in which the PDSCH scheduled by that PDCCH is transmitted. Third, the information includes semi-static DL / UL configuration information. The semi-static DL / UL configuration is slot configuration information configured by a cell-specific RRC signal or a UE-specific RRC signal, and can indicate whether each symbol is a DL symbol, an UL symbol, or a flexible symbol. Fourth, the information includes CORESET and search space configuration information. The CORESET and search space configuration information indicates which slot and at which position the PDCCH may be transmitted. Fifth, the information includes PDSCH repetition information. The PDSCH repetition information may be configured as one of values ​​1, 2, 4, or 8 by an RRC signal, and the same PDSCH is repeatedly transmitted in the slot depending on the configured value. In this case, the start symbol and length of the PDSCH are the same in each slot.For reference, if the PDSCH repetition information is greater than 1, it can be expressed as slot aggregation and reception.

[0139] Referring to FIG. 12, in one embodiment of the present invention, when a terminal is configured to receive data by slot combining, the step of determining a DL association set (or a PDSCH candidate set) may be configured as follows. Here, it is assumed that the PUCCH is located in slot n. Also, the PDSCH repetition value is N rep is.

[0140] First, in the first stage, the terminal receives one K1 value (K 1,k For each K0 and SLIV value (K0, l, SLIV l ) we can check the following: Suppose slot nK 1,k and Slot nK 1,k -1, ... slot nK 1,k -(N rep -1) SLIV in at least one slot l There is no UL symbol in the symbol position specified by nK 1,k -(N rep -1)-If there is a CORESET and search space for PDCCH monitoring in the K0 slot, 1,k ,K 0,l ,SLIV l ) and the assigned PDSCH can be transmitted, and may be included in the DL association set (or PDSCH candidate set). 1,k ,K 0,l ,SLIV l ) and the PDSCH assigned to the DL association set (or PDSCH candidate set) cannot be transmitted, and the terminal cannot include it in the DL association set (or PDSCH candidate set). For example, if at least one UL symbol overlaps with a symbol assigned to a PDSCH symbol in all slots, the PDSCH cannot be transmitted.

[0141] In the second step, the terminal selects a plurality of K1 values ​​(K 1,k ) for multiple K0 and SLIV values ​​(K 0,l ,SLIV l ) the following can be seen in relation to

[0142] For convenience of expression, the combinations that can be included in the DL association set (or PDSCH candidate set) in the first step are indexed as n=1, 2, . . .

[0143] For combination n that can be included in the DL association set (or PDSCH candidate set) in the first step, if the PDSCH allocation of another combination m=n+1,... overlaps with the PDSCH allocation of combination n in at least one symbol in at least one slot, combination m is merged with combination n and combination m is excluded. This method can be performed sequentially for n=1, 2,...

[0144] The dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook) is a method of detecting DTX using a downlink assignment index (DAI). The PDCCH that schedules each PDSCH includes a counter-DAI and a total-DAI. The counter-DAI indicates the number of PDSCHs scheduled from component carrier #0 to the current component carrier. The total-DAI indicates the number of PDSCHs scheduled on all component carriers. By successfully decoding the PDCCH, the terminal can determine the order in which the PDSCH scheduled by the PDCCH was transmitted, and can transmit HARQ-ACK in that order.

[0145] Referring to FIG. 15, when a base station transmits PDSCH to a terminal that can aggregate and use up to eight component carriers using component carriers #0, #1, #3, #4, #5, and #7, 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). If the terminal fails to decode the PDCCH corresponding to component carrier #3, it can determine that it failed to receive one PDSCH from the counter-DAI value of the PDCCH corresponding to component carrier #4. If the terminal fails to decode the PDCCH corresponding to component carrier #7, it can determine from the counter-DAI and total-DAI values ​​of the PDCCH corresponding to component carrier #5 that one PDSCH was scheduled after component carrier #5 but was not successfully received.

[0146] The problem to be solved by the present invention is to provide a method for transmitting a PUCCH including two or more HARQ-ACK information bits in one slot. The reason for this operation is to receive a fast retransmission from the base station by transmitting the HARQ-ACK bit as soon as possible to support services that require low latency and high reliability, such as URLLC services. In 3GPP NR Rel-15, only one PUCCH including a maximum of one HARQ-ACK bit can be transmitted in one slot at any time. Therefore, the terminal must transmit HARQ-ACK responses for different PDSCHs in different slots or multiplex them onto one PUCCH for transmission. As mentioned above, it is inappropriate to transmit HARQ-ACK bits in different slots to reduce latency, and multiplexing them onto the same PUCCH for transmission may cause problems with PUCCH coverage, i.e., reliability. Therefore, in 3GPP NR Rel-16, a method for transmitting a PUCCH including multiple HARQ-ACK information in one slot is under discussion, and this invention discloses such a method.

[0147] 1. PDSCH group indicator

[0148] The UE may receive information about the group indicator (or group ID) of the PDSCH in a PDCCH (or DCI) that schedules the PDSCH, or may infer it from the value of another field transmitted in the DCI or a value configured by RRC. Specific indication and inference methods will be described later. For convenience, the indicator is referred to as a PDSCH group indicator. The UE may multiplex HARQ-ACKs of PDSCHs indicated by the same PDSCH group indicator to generate a HARQ-ACK code block, and then transmit the HARQ-ACKs on the same PUCCH. That is, different PUCCHs can be transmitted in one slot using different PDSCH group indicators.

[0149] FIG. 13 is a diagram illustrating a method for transmitting a PUCCH using a PDSCH group indicator according to an embodiment of the present invention.

[0150] Referring to FIG. 13, the PDSCH group indicator may have two values, 0 or 1, in which case, a maximum of two different PUCCHs can be transmitted in one slot. In the embodiment of FIG. 13, the PUCCHs for transmitting HARQ-ACKs for two PDSCHs whose PDSCH group indicator value is 0 may be determined by the PRI (PUCCH resource indicator) indicated in the PDCCH (or DCI) scheduled later among the two PDSCHs whose PDSCH group indicator value is 0. Also, in the embodiment of FIG. 13, the PUCCHs for transmitting HARQ-ACKs for two PDSCHs whose PDSCH group indicator value is 1 may be determined by the PRI (PUCCH resource indicator) indicated in the PDCCH (or DCI) scheduled later among the two PDSCHs whose PDSCH group indicator value is 1. If the PUCCH resources indicated by the two PRI values ​​do not overlap with each other, the terminal can transmit two PUCCHs in one slot.

[0151] For example, to transmit X PUCCHs in one slot, the PUCCH group indicator must indicate one of the values ​​0, 1, ..., X-1. Therefore, B = ceil(log2(X)) bits are required. This B bit may be explicitly indicated in the PDCCH (or DCI) or may be determined dependently from other factors. The implicit determination method can be similar to the method of implicitly determining the value of the HARQ-ACK multiplexing indicator, which will be described later.

[0152] When configured to transmit multiple PUCCHs in one slot using the PDSCH group indicator, the UE must determine the HARQ-ACK bits, i.e., the HARQ-ACK codebook, to be included in each PUCCH. In particular, when the UE is configured to use a semi-static HARQ-ACK codebook (type-1 HARQ-ACK codebook according to 3GPP TS 38.213), the UE must generate a semi-static HARQ-ACK codebook to be transmitted on a PUCCH corresponding to the PDSCH group indicator. If semi-static HARQ-ACK codebooks corresponding to each PDSCH group indicator are independently generated without separate definition, each PUCCH transmits a semi-static HARQ-ACK codebook of the same size in the same slot, which may result in limited uplink PUCCH coverage. Therefore, the present invention proposes a method for reducing the size of semi-static HARQ-ACK codebooks to be transmitted on PUCCHs corresponding to different PDSCH group indicators in one slot as follows.

[0153] - As a first method, the terminal may divide a slot in half and include PDSCH candidates that may be transmitted in the first half in a semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and include PDSCH candidates that may be transmitted in the second half in a semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1. In other words, the terminal may use information about the time domain occupied by a PDSCH candidate to determine which semi-static HARQ-ACK codebook corresponding to which PDSCH_group_indicator the PDSCH candidate is included in.

[0154] As a second method, the UE may determine which semi-static HARQ-ACK codebook corresponds to which PDSCH_group_indicator the HARQ-ACK of the PDSCH is included in, based on the K1 value indicated in the PDCCH (or DCI). For example, the HARQ-ACK of the PDSCH indicated with the smallest four K1 values ​​among eight K1 values ​​may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0, and the HARQ-ACK of the PDSCH indicated with the largest four K1 values ​​may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0.

[0155] - As a third method, the UE can determine which semi-static HARQ-ACK codebook the HARQ-ACK of the PDSCH corresponds to, based on the PDSCH length (symbols occupied) value indicated in the PDCCH (or DCI). For example, if the PDSCH length is 2 or 4, the HARQ-ACK of the PDSCH is included in the semi-static HARQ-ACK code block corresponding to PDSCH_group_indicator 0, and the HARQ-ACK of the PDSCH with a length of 7 or more can be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 0.

[0156] - As a fourth method, the UE can determine which semi-static HARQ-ACK codebook the HARQ-ACK of the PDSCH corresponds to, based on the PDSCH mapping type indicated in the PDCCH (or DCI). For example, if PDSCH mapping type A is indicated, the HARQ-ACK of the PDSCH is 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 is included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1.

[0157] As a fifth method, the UE can determine which semi-static HARQ-ACK codebook corresponds to which PDSCH_group_indicator the HARQ-ACK of the PDSCH is included in, based on the index of the time domain resource allocation field indicated in the PDCCH (or DCI). For example, the HARQ-ACK of the PDSCH indicated with 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 indicated with the remaining indexes 8 to 15 (bits 1000 to 1111) may be included in the semi-static HARQ-ACK codebook corresponding to PDSCH_group_indicator 1.

[0158] As another alternative, the base station may configure the number of HARQ-ACKs (or PDSCHs) required per slot when configuring a semi-static HARQ-ACK code block for a specific PDSCH_group_indicator in the terminal. For example, if two HARQ-Ack bits are configured per slot, the terminal may generate a semi-static HARQ-ACK codebook including up to two bits per slot when generating a semi-static HARQ-ACK codebook for a specific PDSCH_group_indicator. In other words, the terminal expects to receive up to two PDSCHs indicated by a specific PDSCH_group_indicator in one slot (when there is one bit per PDSCH). The number of HARQ-ACKs (or PDSCHs) required per slot may be configured to different values ​​for semi-static HARQ-ACK codebooks corresponding to different PDSCH_group_indicators.

[0159] - As another alternative, the terminal may configure the HARQ-ACK codebook for a specific PDSCH_group_indicator in a semi-static HARQ-ACK codebook manner, and the HARQ-ACK codebook for another specific PDSCH_group_indicator in a dynamic HARQ-ACK codebook manner.

[0160] - As another alternative, if the terminal receives only one PDSCH having a specific PDSCH group indicator value (i.e., there is no HARQ-ACK for other PDSCHs to be multiplexed), the terminal can transmit only the HARQ-ACK for that one received PDSCH on the PUCCH.

[0161] Alternatively, when a PUCCH resource indicator (PRI) is configured by the base station, the terminal may be configured with a PDSCH group indicator corresponding to each PRI value. For example, if there are four PDSCH group indicators (0, 1, 2, 3) and the terminal is configured with 16 PUCCH configurations and PRI values ​​(here, 0, 1, . . . , 15) from the base station, the base station may configure a PDSCH group indicator value of 0, 1, 2, or 3 for each PUCCH configuration and PRI value. That is, a PDSCH group indicator value of 0 may be configured for PRI values ​​0, 1, 2, and 3, a PDSCH group indicator value of 1 may be configured for PRI values ​​4, 5, 6, and 7, a PDSCH group indicator value of 2 may be configured for PRI values ​​8, 9, 10, and 11, and a PDSCH group indicator value of 3 may be configured for PRI values ​​12, 13, 14, and 16. The terminal can determine the PDSCH group indicator value from the PRI value of the DCI that schedules the PDSCH. In the above example, if the PRI value of the DCI is 10, the terminal can determine that the PDSCH group indicator value is 2.

[0162] Another problem addressed by the present invention relates to a method for transmitting PUCCH in a situation where PUCCH resources indicated by different PDSCH group indicators overlap.

[0163] FIG. 14 is a diagram illustrating a situation in which a collision occurs when transmitting a PUCCH according to a PDSCH group indicator according to an embodiment of the present invention.

[0164] 14, if a PUCCH resource corresponding to PDSCH group indicator 0 of a terminal overlaps with a PUCCH resource corresponding to PDSCH group indicator 1, the terminal cannot simultaneously transmit both PUCCHs. In this case, the terminal can perform one of the two PUCCHs by dropping one PUCCH and transmitting the other PUCCH, or transmit HARQ-ACK codebooks for both PUCCHs in one PUCCH. This invention specifically presents such operations.

[0165] In the operation of dropping one of two PUCCHs and transmitting the other PUCCH, the determination of which PUCCH to transmit is as follows.

[0166] - As a first embodiment, the terminal transmits the PUCCH corresponding to the PDSCH_group_indicator indicated in the last received PDCCH (or DCI), and drops the PUCCH corresponding to the other PDSCH_group_indicator without transmitting it.

[0167] In a second embodiment, of two overlapping PUCCHs, the PUCCH with the lower code rate (more reliable) is transmitted, and the other PUCCH is not transmitted but is dropped.

[0168] In a third embodiment, of two overlapping PUCCHs, the PUCCH of the earlier resource is transmitted, and the PUCCH of the later resource is dropped without being transmitted. The earlier and later resources can be determined based on the last symbol of the resource, and if the last symbols are the same, the resource with the earlier start symbol can be considered the earlier resource.

[0169] As a fourth embodiment, of two overlapping PUCCHs, the PUCCH occupying the longer symbol may be transmitted, and the PUCCH occupying the shorter symbol may be dropped without being transmitted.

[0170] In yet another embodiment, the PUCCH with the smaller PRI (PUCCH resource indicator) value of two overlapping PUCCHs may be transmitted, and the PUCCH with the larger PRI value may be dropped.

[0171] In the operation of transmitting HARQ-ACK codebooks for two PUCCHs in one PUCCH, the HARQ-ACK codebook can be generated as follows.

[0172] As a first embodiment, the terminal may create one large codebook by consecutively concatenating HARQ-ACK codebooks according to the order of the PDSCH_group_indicator values, and transmit the codebook on one PUCCH resource.

[0173] In a second embodiment, the terminal may create a new codebook for PDSCH candidates included in overlapping PUCCHs (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates) and transmit the HARQ-ACK codebook on one PUCCH resource. Alternatively, when the terminal creates one large codebook by consecutively concatenating HARQ-ACK codebooks according to the order of the PDSCH_group_indicator values, the HARQ-ACK bits included in the earlier codebooks may be excluded from the later HARQ-ACK codebooks. The advantage of the second embodiment is that, in the first embodiment, if a HARQ-ACK bit for one PDSCH candidate exists in both overlapping PUCCHs, it is not transmitted redundantly.

[0174] The PDSCH group indicator is one bit and may be included in the DCI scheduling the PDSCH. If the PDSCH is included in a PDSCH group other than the previously transmitted PDSCH group, this one bit can be toggled. When the value of the PDSCH group indicator is toggled, the terminal can determine that the PDSCH is included in a 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 toggled, the terminal can determine that the PDSCH is included in a previous PDSCH group. That is, the PDSCH may be multiplexed with the HARQ-ACK of the previous PDSCH group.

[0175] 2. Finer K1 granularity

[0176] The PDCCH (or DCI) that schedules the PDSCH may indicate a K1 value (PDSCH-to-HARQ feedback timing indicator) to indicate in which slot the HARQ-ACK of the PDSCH is to be transmitted. The K1 value is the number of slots between the slot in which the scheduled PDSCH ends and the slot in which the PUCCH in which the HARQ-ACK is to be transmitted is to be transmitted. Since the K1 value is in units of slots, two or more PUCCHs cannot be transmitted in one slot. To transmit a PUCCH including one or more HARQ-ACKs in one slot, the unit (or granularity) of the K1 value indicated by the DCI may be determined to be a unit smaller than a slot.

[0177] FIG. 15 is a diagram illustrating a method of transmitting a PUCCH when the unit of K1 is a half slot according to an embodiment of the present invention.

[0178] 15, the unit of K1 may be set to half a slot, i.e., the K1 value is the number of half slots between the half slot where the scheduled PDSCH ends and the half slot where the PUCCH in which the HARQ-ACK is transmitted is transmitted.

[0179] When the granularity of K1 is given as a sub-slot (or a set of symbols), the K1 value represents the number of sub-slots between the sub-slot including the last symbol of the PDSCH and the sub-slot including the first symbol of the PUCCH. That is, if the K1 value is 0, it indicates that the sub-slot including the last symbol of the PDSCH and the sub-slot including the first symbol of the PUCCH are the same sub-slot. As another example, when the granularity of K1 is given as a sub-slot (or a set of symbols), the K1 value represents the number of sub-slots between the last sub-slot of the slot including the last symbol of the PDSCH and the sub-slot including the first symbol of the PUCCH. That is, if the K1 value is 0, it indicates that the last sub-slot of the slot ... proc,1 represents the number of subslots between the first subslot and the subslot containing the first symbol of the PUCCH among the subslots after time T. proc,1 represents the minimum time it takes to receive a PDSCH and send a valid HARQ-ACK, this value is specified in TS 38.214.

[0180] Yet another problem addressed by the present invention relates to a method for transmitting PUCCH in a situation where PUCCH resources indicated in half slots (or K1 units) overlap each other in one slot.

[0181] FIG. 16 is a diagram illustrating a situation in which a collision occurs when transmitting a PUCCH when the unit of K1 according to an embodiment of the present invention is a half slot.

[0182] 16, when a PUCCH resource starting in a previous half slot of a terminal overlaps with a PUCCH resource starting in a subsequent half slot, the terminal cannot simultaneously transmit two PUCCHs. In this case, the terminal can take the following actions: drop one of the two PUCCHs and transmit the other PUCCH, or transmit the HARQ-ACK codebooks of the two PUCCHs in one PUCCH. In one embodiment of the present invention, this action is specifically presented.

[0183] In the operation of dropping one of two PUCCHs and transmitting the other PUCCH, the determination of which PUCCH to transmit is as follows.

[0184] As a first embodiment, the terminal transmits the PUCCH indicated by the last received PDCCH (or DCI), and drops the other PUCCHs without transmitting them.

[0185] In a second embodiment, of two overlapping PUCCHs, the PUCCH with the lower code rate (more reliable) is transmitted, and the other PUCCH is not transmitted but is dropped.

[0186] In a third embodiment, of two overlapping PUCCHs, the PUCCH of the earlier resource is transmitted, and the PUCCH of the later resource is dropped without being transmitted. The determination of the earlier and later resources can be made based on the last symbol of the resource, and if the last symbols are the same, the resource whose start symbol is earlier can be considered the earlier resource.

[0187] As a fourth embodiment, of two overlapping PUCCHs, the PUCCH occupying the longer symbol may be transmitted, and the PUCCH occupying the shorter symbol may be dropped without being transmitted.

[0188] In yet another embodiment, the PUCCH with the smaller PRI (PUCCH resource indicator) value of two overlapping PUCCHs may be transmitted, and the PUCCH with the larger PRI value may be dropped.

[0189] In the operation of transmitting the HARQ-ACK codebooks of two PUCCHs in one PUCCH, the HARQ-ACK code block can be generated as follows.

[0190] - As a first embodiment, the terminal can create one large codebook by consecutively concatenating HARQ-ACK codebooks in time order (i.e., the HARQ-ACK codebook for which an earlier half slot and transmission is indicated is positioned before the HARQ-ACK codebook for which a later half slot and transmission is indicated), and transmit the codebook on one PUCCH resource.

[0191] In a second embodiment, the terminal may create a new codebook for PDSCH candidates included in overlapping PUCCHs (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates) and transmit the HARQ-ACK codebook on one PUCCH resource. Alternatively, when the terminal creates one large codebook by sequentially concatenating HARQ-ACK codebooks in time order, HARQ-ACK bits included in earlier codebooks may be excluded from later HARQ-ACK codebooks. An advantage of the second embodiment is that, when an HARQ-ACK bit for one PDSCH candidate exists in both of the two overlapping PUCCHs in the first embodiment, it is not transmitted redundantly.

[0192] 3. HARQ-ACK multiplexing indicator

[0193] In one embodiment of the present invention, a UE may receive, via a PDCCH (or DCI) scheduling a PDSCH, information indicating whether the HARQ-ACK of the PDSCH should be multiplexed with other HARQ-ACKs. For convenience, this indicator is referred to as a HARQ-ACK multiplexing indicator. The HARQ-ACK multiplexing indicator may be defined as 1 bit. In the case of 1 bit, 0 indicates that the HARQ-ACK of the PDSCH is not multiplexed with the HARQ-ACKs of other PDSCHs for transmission, and 1 indicates that the HARQ-ACK of the PDSCH is multiplexed with the HARQ-ACKs of other PDSCHs for transmission. Here, not multiplexing with the HARQ-ACKs of other PDSCHs for transmission means that the PUCCH containing the HARQ-ACK of the PDSCH does not contain HARQ-ACK information of other PDSCHs. Therefore, when the PUCCH is configured to transmit one bit (or two transport blocks in the PDSCH), a 2-bit HARQ-ACK is included, and the HARQ-ACK may be transmitted in one of PUCCH formats, PUCCH format 0 or PUCCH format 1, depending on the bit size. Multiplexing and transmitting with the HARQ-ACK of another PDSCH means that the PUCCH including and transmitting the HARQ-ACK of the PDSCH includes HARQ-ACK information of the other PDSCH. When multiplexing and transmitting with the HARQ-ACK of another PDSCH, a HARQ-ACK codebook is generated using a dynamic HARQ-ACK codebook or a semi-static HARQ-ACK codebook, and the HARQ-ACK codebook is transmitted on the PUCCH.

[0194] FIG. 17 is a diagram illustrating a method for transmitting a PUCCH using a HARQ-ACK multiplexing indicator according to one embodiment of the present invention.

[0195] Referring to FIG. 17, a terminal transmits HARQ-ACK information of two PDSCHs whose HARQ-ACK multiplexing indicators have a value of 1 on one PUCCH. The HARQ-ACKs of two PDSCHs whose HARQ-ACK multiplexing indicators have a value of 0 are transmitted on their respective PUCCH resources. The PUCCH resources of PDSCHs whose HARQ-ACK multiplexing indicators have a value of 0 are indicated by the PRI value scheduling the PDSCHs. If PUCCHs transmitting HARQ-ACKs of different PDSCHs whose HARQ-ACK multiplexing indicators have a value of 0 (cannot be multiplexed with the HARQ-ACK of another PDSCH) overlap in the same symbol, simultaneous transmission is not possible. In this case, the HARQ-ACK information of the two PUCCHs may be multiplexed and transmitted on one PUCCH. Alternatively, the terminal may prioritize the HARQ-ACK of a later scheduled PDSCH (i.e., when the PDCCH that schedules the PDSCH starts or ends late) and transmit the PUCCH of the PDSCH, without transmitting other overlapping PUCCHs. Alternatively, the terminal may not expect the two PUCCHs to overlap in one symbol.

[0196] In yet another embodiment of the present invention, even when the HARQ-ACK multiplexing indicator value indicates 0 (multiplexing with the HARQ-ACK of another PDSCH is not possible), partial HARQ-ACK multiplexing may be enabled. For example, if two PDSCHs indicated by a HARQ-ACK multiplexing indicator value of 0 are to be transmitted on the same PUCCH resource (or have the same PRI (PUCCH resource indicator) value or overlap in at least one symbol), the HARQ-ACKs of the two PDSCHs may be multiplexed and transmitted. In this case, the HARQ-ACK bit of the later scheduled PDSCH is located next to the HARQ-ACK bit of the earlier scheduled PDSCH.

[0197] FIG. 18 is a diagram illustrating a method of HARQ-ACK multiplexing using PRI when transmitting PUCCH according to an HARQ-ACK multiplexing indicator according to one embodiment of the present invention.

[0198] Referring to (a) of Figure 18, if the PRI values ​​of the PDSCHs indicated by the HARQ-ACK multiplexing indicator value of 0 are the same as i, the terminal can transmit HARQ-ACKs of the two PDSCHs on the PUCCH resource corresponding to PRI=i.

[0199] Referring to (b) of FIG. 18, when the PRI values ​​of the PDSCH indicated by the HARQ-ACK multiplexing indicator value being 0 are different from each other, the terminal can transmit each HARQ-ACK information on the PUCCH resource corresponding to each PRI value.

[0200] A PUCCH resource for transmitting a HARQ-ACK of a PDSCH whose HARQ-ACK multiplexing indicator has a value of 1 may overlap with a PUCCH resource for transmitting a HARQ-ACK of a PDSCH whose HARQ-ACK multiplexing indicator has a value of 0. As a PUCCH transmission method in such a case, according to one embodiment of the present invention, a terminal may always prioritize and transmit a PUCCH for transmitting a HARQ-ACK of a PDSCH whose HARQ-ACK multiplexing indicator has a value of 0, and may drop a PUCCH for transmitting a HARQ-ACK of a PDSCH whose HARQ-ACK multiplexing indicator has a value of 1. In yet another embodiment, if the last symbol of the PUCCH transmitting the HARQ-ACK of the PDSCH whose HARQ-ACK multiplexing indicator value is 1 ends earlier or at the same time as the last symbol of the PUCCH transmitting the HARQ-ACK of the PDSCH whose HARQ-ACK multiplexing indicator value is 0, the terminal can transmit the HARQ-ACK bit of the PDSCH whose HARQ-ACK multiplexing indicator value is 0 on the PUCCH resource of the PDSCH whose HARQ-ACK multiplexing indicator value is 1, following the HARQ-ACK of the PDSCH whose HARQ-ACK multiplexing indicator value is 1.

[0201] For convenience, the HARQ-ACK multiplexing indicator is expressed as one bit, but this indicator may be indicated implicitly as follows.

[0202] As a first method, the HARQ-ACK multiplexing indicator can be determined by the RNTI. For example, if a PDCCH (or DCI) scheduling a PDSCH is scrambled with a C-RNTI, the HARQ-ACK multiplexing indicator of the PDSCH can be determined to have a value of 1 (i.e., multiplexing with HARQ-ACK information of other PDSCHs is possible), and if a PDCCH (or DCI) scheduling a PDSCH is scrambled with a specific RNTI other than the C-RNTI (e.g., an RNTI for a URLLC service), the HARQ-ACK multiplexing indicator of the PDSCH can be determined to have a value of 0 (multiplexing with HARQ-ACK information of other PDSCHs is not possible).

[0203] - As a second method, the HARQ-ACK multiplexing indicator can be determined by the K1 value included in the PDCCH (or DCI). Here, the K1 value indicates the time interval between a scheduled PDSCH and the HARQ-ACK for that PDSCH. Therefore, the PDSCH for a URLLC service generally needs to indicate an early HARQ-ACK. Therefore, if the K1 value is smaller than a specific K1 value, the HARQ-ACK multiplexing indicator can be determined to be 0. Here, the specific K1 value can be determined in slot units (e.g., 1 slot or 2 slots) or in absolute time units (e.g., 0.5 ms or 0.25 ms). Alternatively, a specific value of K1 can be determined, and when this value is indicated, the HARQ-ACK multiplexing indicator value can always be determined to be 0. That is, when this value is indicated to the terminal, the terminal does not generate a codebook and can transmit only a HARQ-ACK for one PDSCH.

[0204] As a third method, the HARQ-ACK multiplexing indicator can be determined according to the modulation and coding scheme (MCS) value. Here, the MCS value indicates the code rate of the scheduled PDSCH. The PDSCH for the URLLC service generally needs to be reliable. Therefore, if the code rate value is lower than a specific value, the HARQ-ACK multiplexing indicator can be determined to be 0. As yet another example, the HARQ-ACK multiplexing indicator can be determined according to the MCS table used by the PDCCH (or DCI). If a specific PDCCH (or DCI) uses an MCS table that provides higher reliability (lower code rate), the value of the HARQ-ACK multiplexing indicator for the PDCCH (or DCI) can be determined to be 0.

[0205] - As a fourth method, the HARQ-ACK multiplexing indicator can be determined to be 1 by a combination of specific values ​​of other fields transmitted in the DCI.

[0206] As a fifth method, the HARQ-ACK multiplexing indicator may be determined according to the search space (or CORESET) in which the PDCCH (or DCI) is detected. For example, the base station may separately instruct the terminal of a search space (or CORESET) for URLLC transmission. When the terminal receives the PDCCH (or DCI) in the search space (or CORESET), the terminal may determine the value of the HARQ-ACK multiplexing indicator to be 0. When the terminal receives the PDCCH (or DCI) in another search space (or CORESET), the terminal may determine the value of the HARQ-ACK multiplexing indicator to be 1. As yet another method, the terminal may distinguish the search space (or CORESET) without a separate explicit instruction from the base station. For example, if the monitoring period of the search space (or CORESET) is shorter than a specific period, the terminal may determine the search space (or CORESET) as the search space (or CORESET) for URLLC transmission. In one embodiment, the specific period may be one slot.

[0207] As a sixth method, the terminal may determine the value of the HARQ-ACK multiplexing indicator according to the CCE (control channel element) aggregation level of the received PDCCH. For example, if the CCE aggregation level exceeds a specific value, the terminal may determine the HARQ-ACK multiplexing indicator of the PDCCH to be 0. Here, the specific CCE aggregation level value may be set to 8 or 16.

[0208] As a seventh method, the value of the HARQ-ACK multiplexing indicator can be determined depending on the DCI format (or the length of the DCI). For example, if a compact DCI is configured in the terminal, the terminal can determine that the value of the HARQ-ACK multiplexing indicator for the PDSCH scheduled by the compact DCI is 0. Here, the compact DCI is a DCI format for scheduling a URLLC PDSCH, and is characterized by having a payload size smaller than that of a fallback DCI (DCI format 0_0 / 1_0).

[0209] As an eighth method, the value of the HARQ-ACK multiplexing indicator can be determined according to the value of the PUCCH resource indicator (PRI). Here, the PRI transmitted on the PUCCH (or DCI) indicates which PUCCH resource the base station configures for the terminal to use. When a specific value of the PRI is indicated to the terminal, the terminal can determine the value of the HARQ-ACK multiplexing indicator to be 0. This is because all configured PUCCH resources are not suitable for transmitting the URLLC HARQ-ACK. For example, since a PUCCH resource with more than 2 bits among the PUCCH resources is not suitable for transmitting the URLLC HARQ-ACK, the terminal can determine the value of the HARQ-ACK multiplexing indicator for the PRI indicating the PUCCH resource to be 1.

[0210] As a ninth method, the value of the HARQ-ACK multiplexing indicator can be determined according to the HARQ process number. For example, if a specific value of the HARQ process number is specified for the UE, the UE can determine the value of the HARQ-ACK multiplexing indicator as 1 and transmit only the HARQ-ACK for one PDSCH.

[0211] As a tenth method, the value of the HARQ-ACK multiplexing indicator can be determined according to the PDSCH group indicator value. As mentioned above, the PDSCH group indicator is introduced to transmit HARQ-ACKs on the same PUCCH resource. When the UE receives a specific value of the PDSCH group indicator, the UE determines the value of the HARQ-ACK multiplexing indicator to be 1 and can transmit only HARQ-ACKs for one PDSCH.

[0212] Yet another embodiment of the present invention relates to how the terminal interprets the K1 value.

[0213] As described above, the K1 value is the number of slots between the slot where the scheduled PDSCH ends and the slot where the PUCCH for transmitting the HARQ-ACK is transmitted (here, the slot can be replaced with a specific unit smaller than a slot). However, in practice, a UE may incur processing time when receiving and decoding the PDSCH and generating the PUCCH for transmitting the HARQ-ACK. For this reason, a specific K1 value, for example, 0, is a value that cannot be specified. The problem to be solved by the present invention is to define the K1 value excluding the value that cannot be specified.

[0214] In a first embodiment of the present invention, the terminal receives a PDSCH processing time T proc,1 (values ​​defined in TS 38.214) may be excluded when determining the K1 value. That is, when the slots are called invalid slots, the K1 value can be defined as the number of slots excluding invalid slots among the slots between the slot where the scheduled PDSCH ends and the slot where the PUCCH in which the HARQ-ACK is transmitted is transmitted.

[0215] In a second embodiment of the present invention, the UE cannot transmit the corresponding PUCCH in a semi-static DL symbol configured by a higher layer. Therefore, the UE may exclude slots consisting of only semi-static DL symbols when determining the K1 value. Alternatively, the UE may exclude slots in which no PUCCH transmission is possible due to semi-static DL symbols when determining the K1 value. Alternatively, when the UE refers to slots in which the PUCCH cannot be transmitted because the PUCCH resource indicated by the PRI overlaps with a semi-static DL symbol as invalid slots, the K1 value may be defined as the number of slots excluding invalid slots among slots between the slot in which the scheduled PDSCH ends and the slot in which the PUCCH in which the HARQ-ACK is transmitted is transmitted.

[0216] In order to reduce DCI overhead (payload size of DCI) in a PDCCH (or DCI) that schedules URLLC, the K1 or PRI field may not be configured. One embodiment of the present invention describes a method for determining a PUCCH resource when the K1 or PRI field is not configured.

[0217] In a first embodiment of the present invention, when the K1 field (PDSCH-to-HARQ_feedback timing indicator field) is not configured, the slot containing the PUCCH resource is set to the PDSCH processing time T from the last symbol of the PDSCH. proc,1 (values ​​defined in TS 38.214), it may be the next slot in which PUCCH transmission (as indicated by PRI) is possible.

[0218] - As a second embodiment of the present invention, when the K1 field (PDSCH-to-HARQ_feedback timing indicator field) is not configured, the slot containing the PUCCH resource may be a slot in which the symbol indicated by the PRI does not overlap with the semi-static DL symbol.

[0219] 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 slot indicated by K1.

[0220] In a fourth embodiment of the present invention, when the PRI field is not configured, the PUCCH resource is allocated to the PDSCH processing time T proc,1 It may be the PUCCH resource that ends earliest among the PUCCH resources excluding the PUCCHs that do not satisfy the value defined in TS 38.214. Here, PUCCH resources that overlap with semi-static DL symbols may be excluded.

[0221] FIG. 19 illustrates a method for transmitting a PUCCH when there is no K1 or PRI field according to one embodiment of the present invention.

[0222] Referring to Figure 19, when neither the K1 nor the PRI field is configured in the PDCCH (or DCI), the terminal determines the PUCCH resource in the following manner. In the embodiment of Figure 19, a total of four PUCCH resources are configured. Among them, PUCCH resource #1 may be excluded because it does not satisfy the processing time condition. Among the other PUCCH resources #2, #3, and #4, #3 is the PUCCH resource that ends earliest, so the terminal can determine #3 as the PUCCH resource for HARQ-ACK of the PDSCH.

[0223] Another problem to be solved by the present invention relates to a method for designing a dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook in TS 38.213). A base station can be configured to omit some fields from the DCI field to increase the probability of successful reception of a PDCCH by a terminal. Here, "omit" means configuring a 0 bit. For example, a base station can configure a terminal to omit the counter-DAI field from the DCI field. As described above, the counter-DAI field in a dynamic HARQ-ACK codebook not only determines the position of the HARQ-ACK bit in the HARQ-ACK codebook, but also may be used to determine the size of the HARQ-ACK codebook. To transmit HARQ-ACK bits of multiple PDSCHs using the HARQ-ACK codebook, the terminal must sort them in ascending order of the value of the counter-DAI field. However, since the counter-DAI field is omitted, a method for determining the order of HARQ-ACK bits in the HARQ-ACK codebook is required.

[0224] In a first embodiment of the present invention, a terminal may determine the order of HARQ-ACK bits of PDSCHs in a HARQ-ACK codebook according to time information when a PDCCH scheduling a PDSCH is received. More specifically, if the start symbol of a CORESET or search space including a PDCCH scheduling a first PDSCH is earlier than the start symbol of a CORESET or search space including a PDCCH scheduling a second PDSCH, the terminal arranges the HARQ-ACK bit of the first PDSCH at a position earlier than the HARQ-ACK bit of the second PDSCH in the HARQ-ACK codebook. If the start symbols of the CORESETs or search spaces are the same, the last symbol of the CORESET or search space is arranged earlier than the HARQ-ACK bit of the PDSCH scheduled by the earlier PDCCH.

[0225] In a second embodiment of the present invention, a terminal can determine the order of HARQ-ACK bits of the PDSCHs in a HARQ-ACK codebook according to time information of the PDSCHs. More specifically, if the start symbol of a first PDSCH is earlier than the start symbol of a second PDSCH, the HARQ-ACK bit of the first PDSCH is arranged in a position earlier than the HARQ-ACK bit of the second PDSCH in the HARQ-ACK codebook. Here, information about the start symbol can be obtained from the time domain resource assignment (TDRA) field of the PDCCH that schedules the PDSCH. If the start symbols of the PDSCHs are the same, the HARQ-ACK bit of the PDSCH whose last symbol is earlier is arranged in an earlier position. If the start symbols and last symbols are the same, the order of HARQ-ACK bits in the HARQ-ACK codebook can be determined using another embodiment.

[0226] In a third embodiment of the present invention, the terminal can determine the order of HARQ-ACK bits in the HARQ-ACK codebook according to the value of the HARQ process ID (or HARQ process number) of the PDCCH that schedules the PDSCH. More specifically, when the HARQ process ID of the first PDSCH in the PDCCH that schedules the first PDSCH is A and the HARQ process ID of the second PDSCH in the PDCCH that schedules the second PDSCH is B, the HARQ-ACK bit of the PDSCH having a smaller value of A or B in the HARQ-ACK codebook can be arranged in a position before the HARQ-ACK bit of the PDSCH having a larger value. That is, the position of the HARQ-ACK bit can be determined in ascending order of the HARQ process ID. Here, the terminal assumes that the HARQ process IDs of HARQ-ACKs transmitted using one HARQ-ACK codebook are different from each other. That is, it is not expected that HARQ-ACK bits of PDSCHs having the same HARQ process ID are generated in one HARQ-ACK codebook.

[0227] In a fourth embodiment of the present invention, a terminal may determine the order of HARQ-ACK bits of a PDSCH in a HARQ-ACK codebook using information about a cell that has received a PDCCH scheduling a PDSCH. Here, the cell information may be a cell index (or ID). The terminal may be configured to monitor PDCCHs in multiple cells. In this case, the terminal may receive different PDCCHs in different cells. In this case, the terminal may arrange the order of HARQ-ACK bits of PDSCHs received in different cells in the HARQ-ACK codebook in ascending order of the indexes of the cells that have received the PDCCH scheduling a PDSCH.

[0228] In a fifth embodiment of the present invention, a terminal may determine the order of HARQ-ACK bits of a PDSCH in a HARQ-ACK codebook using information about a CORESET (or search space) in which a PDCCH scheduling a PDSCH is received. Here, the information about the CORESET (or search space) may be an index (or ID) of the CORESET (or search space). The terminal may be configured to monitor PDCCHs in multiple CORESETs (or search spaces). In this case, the terminal may receive different PDCCHs in different CORESETs (or search spaces). In this case, the terminal may arrange the order of HARQ-ACK bits of PDSCHs received in different CORESETs (or search spaces) in the HARQ-ACK codebook in ascending order of the indexes of the CORESETs (or search spaces) in which a PDCCH scheduling a PDSCH is received.

[0229] In a sixth embodiment of the present invention, a UE may determine the order of HARQ-ACK bits of the PDSCH in a HARQ-ACK codebook using frequency domain information received from a PDCCH that schedules the PDSCH. Here, the frequency domain information may be the lowest PRB index among PRBs to which a PDCCH is assigned. Here, the index refers to a common PRB index, and indicates how far the index is from Point A in the frequency domain. Point A refers to a reference frequency in the initial access process of a UE. According to TS 38.211, Point A is as follows:

[0230] - offsetToPointA for a PCell downlink where offsetToPointA represents the frequency offset between point A and the lowest subcarrier of the lowest resource block, which has the subcarrier spacing provided by the higher-layer parameter subCarrierSpacingCommon and overlaps with the SS / PBCH block used by the UE for initial cell selection, expressed in units of resource blocks assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2; - absoluteFrequencyPointA for all other cases where absoluteFrequencyPointA represents the frequency-location of point A expressed as in ARFCN.

[0231] The terminal may be configured to monitor multiple PDCCHs. In this case, the terminal can receive different PDCCHs in different frequency regions. In this case, the terminal can arrange the order of HARQ-ACK bits of PDSCHs received in different frequency regions in the HARQ-ACK codebook in ascending order of the lowest PRB index of the PDCCH scheduling the PDSCH. This method can determine the order of HARQ-ACK bits in the HARQ-ACK codebook when multiple PDCCHs are received in one CORESET (or search space) in the fifth embodiment.

[0232] The above first to sixth embodiments can be combined with each other to determine the order of HARQ-ACK bits in the HARQ-ACK codebook. A preferred combination of the present invention may be a combination of the first embodiment and the third embodiment. With this combination, the order of HARQ-ACK bits in the HARQ-ACK codebook is first determined by time domain information of the PDCCH, and when the order cannot be determined by the time domain information, the order may be determined by the HARQ process ID in the third embodiment. A preferred combination of the present invention may be a combination of the first, fourth, fifth, and sixth embodiments. With this combination, the order of HARQ-ACK bits in the HARQ-ACK codebook is first determined by time domain information of the PDCCH, and when the order cannot be determined by the time domain information, the order may be determined by cell information, and when the order cannot be determined by the cell information, the order may be determined by CORESET (or search space) information, and when the order cannot be determined by CORESET (or search space) information, the order may be determined by frequency domain allocation information of the PDCCH.

[0233] Another problem to be solved by the present invention is when a PDCCH corresponding to a HARQ-ACK in one HARQ-ACK codebook includes two types of DCI, such as a DCI with a counter-DAI field and a DCI without a counter-DAI field. In this case, a terminal must determine the location of the HARQ-ACK of the PDSCH scheduled with the DCI with a counter-DAI field and the HARQ-ACK of the PDSCH scheduled with the DCI without a counter-DAI field in the HARQ-ACK codebook.

[0234] As one embodiment of the present invention, in the above situation, the terminal generates a first sub-HARQ-ACK codebook by collecting only HARQ-ACKs of PDSCHs scheduled by DCIs having a counter-DAI field. In this case, the position of the HARQ-ACK in the first sub-HARQ-ACK codebook is determined using the value of the counter-DAI field (i.e., the position is determined in ascending order of counter-DAI). Then, the terminal generates a second sub-HARQ-ACK codebook by collecting only HARQ-ACKs of PDSCHs scheduled by DCIs having no counter-DAI field. In this case, the position of the HARQ-ACK in the second sub-HARQ-ACK codebook may be determined according to the above first to sixth embodiments or a combination thereof. The UE can generate the HARQ-ACK codebook by consecutively combining the first sub-HARQ-ACK codebook and the second sub-HARQ-ACK codebook (i.e., the first bit of the second sub-HARQ-ACK codebook follows the last bit of the first sub-HARQ-ACK codebook). This method requires the UE to generate two sub-HARQ-ACK codebooks in different ways, which may increase UE complexity.

[0235] In yet another embodiment of the present invention, in the above situation, the terminal can ignore the counter-DAI field even if the DCI has the counter-DAI field, that is, it can regard all DCI as DCI without the counter-DAI field, and determine the position of the HARQ-ACK bit in the HARQ-ACK codebook according to the above embodiments 1 to 6 and combinations thereof.

[0236] Another problem to be solved by the present invention is 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 DCI overhead, other DCI fields may be omitted, or only some of the options that the DCI field can indicate may be included. If only some of the options that the DCI field can indicate (e.g., N options) are included, the bit size of the DCI field is ceil(log2(N)). However, if N is not a power of 2, 2^XN code points of the DCI field cannot be used. Here, X is the smallest integer such that 2^X is greater than or equal to N. Therefore, to use this more efficiently, different DCI fields must be jointly encoded.

[0237] As an embodiment of the present invention, assume that the jth DCI field includes Y(j) options (0th option, 1st option, ...). When the terminal receives DCI from the base station, the number of options in the jth DCI field can be calculated using the following formula. Here, the number is assigned starting from 0 (i.e., the earliest option is 0).

[0238] Field(j)=floor(X / Z(j)) mod Y(j)

[0239] where:

number

number

[0240] For example, the following table relates to a case where the DCI has three fields, each containing three options. If we calculate the number of bits for each DCI field, there are three fields, each with two bits, so six bits are required. However, if the proposed method is used, five bits are sufficient. In Table 4 below, 11011 to 11111 may be reserved.

[0241] [Table 4]

[0242] For example, if DCI indicates 01100 to a terminal, it is possible to obtain Field (1) = 0, Field (2) = 1, and Field (3) = 1. In other words, it is clear that the first DCI field indicates Field (1) = 0th option, the second DCI field indicates Field (2) = 1st option, and the third DCI field indicates Field (3) = 1st option.

[0243] Another problem addressed by the present invention relates to a method for dividing a slot into subslots. For example, when dividing a slot consisting of 14 symbols into two subslots, each subslot may consist of seven consecutive symbols. The first subslot may consist of the first seven symbols of the slot, and the second subslot may consist of the last seven symbols of the slot. As yet another example of the present invention, when dividing a slot consisting of 14 symbols into two subslots, the first subslot may consist of odd-numbered symbols of the slot, and the second subslot may consist of even-numbered symbols of the slot. In general, as a first method for dividing a slot consisting of K symbols into N subslots, (K mod N) subslots may consist of floor(K / N)+1 consecutive symbols, and N-(K mod N) subslots may consist of floor(K / N) consecutive symbols. Of the N subslots, (K mod N) subslots with one more symbol may be located in the first half of the slot, and N-(K mod N) subslots with one less symbol may be located in the second half of the slot. Of the N subslots, N-(K mod N) subslots with one less symbol may be located in the first half of the slot, and N-(K mod N) subslots with one more symbol may be located in the second half of the slot. Of the N subslots, (K mod N) subslots with one more symbol and N-(K mod N) subslots with one less symbol may be alternately located. Generalizing, as a second method of dividing a slot consisting of K symbols into N subslots, the nth subslot may be composed of floor(K / N)*i+nth (i=0, 1, ..) symbols.

[0244] Alternatively, the UE may divide the subslots according to the time domain resource assignment information of the configured PDSCH. For example, the subslots may be divided according to the order of the positions of the last symbols of the PDSCH in the time domain resource assignment information of the PDSCH. The first A PDSCH symbols in order up to the last symbol may be divided into the first subslot. The rest may then be divided using the above method.

[0245] According to another method, the UE can divide the subslots using information about symbols occupied by the configured PUCCHs. For example, the subslots can be divided according to the order of the positions of the last symbols of the PUCCHs in the information about symbols occupied by the PUCCHs. The first A PUCCH symbols in order up to the last symbol can be divided into the first subslot. Then, the rest can be divided using the above method.

[0246] Another problem to be solved by the present invention relates to a method for generating a semi-static HARQ-ACK codebook when K1 granularity is configured as a sub-slot. More specifically, the problem to be solved is as follows.

[0247] FIG. 20 is a diagram showing how PDSCH candidates are set in slots.

[0248] Referring to FIG. 20, assume that there are three PDSCH candidates in one slot. The first subslot contains PDSCH candidate #1 (whether it is included or not is determined by whether the last symbol of the PDSCH candidate is included). The second subslot contains PDSCH candidate #2 and PDSCH candidate #3. PDSCH candidate #1 and PDSCH candidate #2 overlap in the same symbol, while PDSCH candidate #3 does not overlap with other PDSCH candidates. When only one PDSCH can be received in the same symbol, a terminal can simultaneously receive a maximum of two PDSCH candidates in that slot. For example, the possible PDSCH candidates are {PDSCH candidate #1}, {PDSCH candidate #2}, {PDSCH candidate #3}, {PDSCH candidate #1, PDSCH candidate #3}, and {PDSCH candidate #2, PDSCH candidate #3}. Based on this, the number of HARQ-ACK bits that the UE should include in the semi-static HARQ-ACK codebook for the PDSCH candidate of the slot is two (assuming one PDSCH candidate transmits one HARQ-ACK bit). Given that the granularity of K1 is half-slots, we will now describe how to generate a semi-static HARQ-ACK codebook for each half-slot. The PDSCH combination receivable in the first half-slot is {PDSCH candidate #1}, so there is a maximum of one. Therefore, a one-bit HARQ-ACK must be included in the semi-static HARQ-ACK codebook for this half-slot. The PDSCH combinations receivable in the second half-slot are {PDSCH candidate #2}, {PDSCH candidate #3}, and {PDSCH candidate #2, PDSCH candidate #3}, so there are a maximum of two. Therefore, a 2-bit HARQ-ACK must be included in the semi-static HARQ-ACK codebook for this half-slot, resulting in a total of 3 bits of HARQ-ACK for one slot being included in the semi-static HARQ-ACK codebook.As mentioned above, the maximum number of PDSCHs that can be transmitted in one slot is two, and it can be seen that an extra one-bit overhead occurs compared to including a two-bit HARQ-ACK in a semi-static HARQ-ACK codebook. In the present invention, a method for reducing such overhead is proposed.

[0249] In one embodiment of the present invention, when the K1 granularity is a subslot, the terminal aggregates all subslots included in one slot and generates a semi-static HARQ-ACK codebook using the PDSCH candidates included in the subslot. That is, the semi-static HARQ-ACK codebook transmitted in subslot n may be generated as follows:

[0250] FIG. 21 illustrates a process of removing overlapping PDSCH candidates according to an embodiment of the present invention.

[0251] Referring to Figure 21, 1) A set of K1 values ​​that can be indicated is defined as K1_set. The maximum K1 value is extracted from K1_set. This is defined as K1_max. The index of the slot including the subslot corresponding to n-K1_max is defined as X. One slot is composed of N_subslots, and X is expressed as X = floor((n-K1_max) / N_subslot). A K1 value indicating the subslot included in slot X is extracted from K1_set. That is, if the elements of the K1 set are defined as K1_value, all K1_values ​​that satisfy X = floor((n-K1_value) / N_subslot) are extracted. The set of K1 values ​​(including K1_max) extracted in the above process is defined as K1_max_set. The extracted K1 value is excluded from K1_set.

[0252] 2) Let R be a set of PDSCH candidates that can be received in a slot. If the last subslot among the subslots that overlap with the DL slot of a PDSCH candidate included in set R is included in the subslots included in K1_max_set, the PDSCH candidate is kept in set R; otherwise, it is removed from set R. Also, if a symbol of a PDSCH candidate included in set R overlaps with a symbol configured as an uplink in a semi-static UL / DL configuration, the PDSCH candidate is removed from set R.

[0253] 3) The terminal performs the following steps A and B for the PDSCH candidates included in R.

[0254] A. A new bit is assigned to the PDSCH candidate whose last symbol is the earliest. If there is a PDSCH candidate in set R that overlaps with the PDSCH candidate by even one symbol, the PDSCH candidate is assigned the same bit position as the PDSCH candidate whose last symbol is the earliest. The PDSCH candidates (including the PDSCH candidate whose last symbol is the earliest) are excluded from set R.

[0255] B. Repeat step 3-A above until set R is an empty set.

[0256] 4) Repeat steps 1), 2) and 3) above until K1_set becomes an empty set.

[0257] It is still another object of the present invention to provide a specific method for designing a type-1 HARQ-ACK codebook when sub-slots are configured.

[0258] According to an embodiment of the present invention, the terminal uses a K1 value (hereinafter referred to as K 1,k ) is the slot-level K1 value (hereafter referred to as K 1,k,slot ) More specifically, the slot-level K1 value may be determined as follows:

[0259]

number

[0260] where n U is the index of the subslot in which the PUCCH is transmitted, and N is the number of subslots in the slot. For example, when 14 symbols are configured in one slot, N is one of the values ​​from 2 to 7, and when 12 symbols are configured in one slot, N is one of the values ​​from 2 to 7. Here,

number

[0261] FIG. 22 is a diagram illustrating a process of generating a type-1 HARQ-ACK according to one embodiment of the present invention.

[0262] Referring to FIG. 22, the subcarrier spacing of the downlink cell of the terminal is 30 kHz, and the subcarrier spacing of the uplink cell is 15 kHz. The slot of the uplink cell is divided into seven subslots, each consisting of two consecutive symbols. That is, N=7. The terminal uses subslot 12 (n U = 12), a type-1 HARQ-ACK codebook to be included in the PUCCH must be generated. The K1 value set as the subslot granularity is K1 = {8, 7, 4, 3}.

[0263] Referring to FIG. 22, according to one embodiment of the present invention, the K1 value set as the sub-slot granularity is the K1 value K 1,k,slot which may be transformed into:

[0264]

number

[0265] The terminal calculates the K 1,k,slot The value can be used to determine the PDSCH candidates in each slot. More specifically, the pseudo-code for generating the type-1 HARQ-ACK codebook is 1,k When performed in descending order of 1,k By value K 1,k,slot The calculated K 1,k,slot Based on the value, a type-1 HARQ-ACK codebook may be generated.

[0266] The terminal is the K selected above. 1,k The validity of the PDSCH candidate to be included in the type-1 HARQ-ACK codebook can be checked based on the value. If valid, the PDSCH candidate can be included in the type-1 HARQ-ACK codebook; if not, the PDSCH candidate can be excluded from the type-1 HARQ-ACK codebook. This process can be determined based on whether the last symbol (ending point) of the PDSCH candidate is included in a specific subslot. If it is determined that the last symbol (ending point) of the PDSCH candidate is included in a specific subslot, the PDSCH candidate is determined to be valid. If not, the PDSCH candidate is determined to be invalid. Here, the specific subslot is subslot n U -K 1,k is.

[0267] FIG. 23 is a diagram illustrating a process of generating a type-1 HARQ-ACK according to one embodiment of the present invention.

[0268] Referring to FIG. 23, when K1, 0=8 is selected, the terminal determines that the PDSCH candidate in DL slot 1 is in subslot n U -K 1,0= subslot 4. In the example of Figure 23, let us assume that two PDSCH candidates are configured in the terminal. The first PDSCH candidate is shown as "A" in Figure 23, and the second PDSCH candidate is shown as "B" in Figure 23. The terminal checks whether the last symbol (ending point) of each PDSCH candidate is valid in subslot n. U -K 1,0 It can be determined whether the first PDSCH candidate (A) is included in subslot n. If it is determined that it is included, the PDSCH candidate is determined to be valid. If not, the PDSCH candidate is determined to be invalid. The last symbol (ending point) of the first PDSCH candidate (A) is in subslot n. U -K 1,0 = Not included in subslot 4, but included in subslot 5. Therefore, it can be determined that the first PDSCH candidate (A) is invalid. The last symbol (ending point) of the second PDSCH candidate (B) is in subslot n U -K 1,0 = included in subslot 4. Therefore, the second PDSCH candidate (B) can be determined to be valid.

[0269] Referring to Figure 23, K 1,1 = 7, the terminal determines that the PDSCH candidate in DL slot 1 is U -K 1,1 = subslot 5. The terminal must determine whether the last symbol (ending point) of each PDSCH candidate is valid in subslot n. U -K 1,1 If it is determined that the PDSCH candidate is included in subslot n, the PDSCH candidate is determined to be valid. If not, the PDSCH candidate is determined to be invalid. If the last symbol (ending point) of the first PDSCH candidate (A) is in subslot n, the PDSCH candidate is determined to be valid. U -K 1,1 = subslot 5. Therefore, it can be determined that the first PDSCH candidate (A) is valid. The last symbol (end point) of the second PDSCH candidate (B) is included in subslot n U -K 1,1= Not included in subslot 5, but included in subslot 4. Therefore, it can be determined that the second PDSCH candidate (B) is not valid.

[0270] Referring to FIG. 23, when K1,2=4 is selected, the terminal determines that the PDSCH candidate for DL ​​slot 2 is in subslot n U -K1,2 = whether it is valid for subslot 8. The terminal determines whether the last symbol (ending point) of each PDSCH candidate is valid for subslot n U It can be determined whether -K1,2 = subslot 8 is included. If it is determined that it is included, the PDSCH candidate is determined to be valid. If not, the PDSCH candidate is determined to be invalid. The last symbol (ending point) of the first PDSCH candidate (A) is in subslot n U -K1,2 = included in subslot 8. Therefore, the first PDSCH candidate (A) can be determined to be valid. The last symbol (end point) of the second PDSCH candidate (B) is included in subslot n U -K1,2 = included in subslot 8. Therefore, the second PDSCH candidate (B) can be determined to be valid.

[0271] Referring to Figure 23, K 1,3 If =3 is selected, the terminal determines that the PDSCH candidate in DL slot 2 is U -K 1,3 = subslot 9. The terminal must determine whether the last symbol (ending point) of each PDSCH candidate is valid for subslot n. U -K 1,3 If it is determined that the PDSCH candidate is included, it is determined that the PDSCH candidate is valid. If not, it is determined that the PDSCH candidate is invalid. The last symbol (ending point) of the first PDSCH candidate (A) is in subslot n. U -K 1,3= Not included in subslot 9, but included in subslot 8. Therefore, it can be determined that the first PDSCH candidate (A) is invalid. The last symbol (ending point) of the second PDSCH candidate (B) is in subslot n U -K 1,3 = Not included in subslot 9, but included in subslot 8. Therefore, it can be determined that the second PDSCH candidate (B) is not valid.

[0272] More specifically, it is effective if the following is satisfied:

[0273] <Validity conditions>

[0274] if subslotLengthForPUCCH-r16 is provided and sub-slot n U -K 1,K is the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived by row r in slot

number

[0275] where n U,slot is the sub-slot n U is the index of the slot corresponding to

number

[0276] It is not valid if the following is true:

[0277] <Invalid conditions>

[0278] if subslotLengthForPUCCH-r16 is provided and sub-slot n U -K 1,Kis not the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived by row r in slot

number

[0279] With this modification, the existing Rel-15 / 16 pseudo-code for generating type-1 HARQ-ACK can be applied to sub-slot configuration with minimal modification. More specific pseudo-code is as follows. For reference, all variables here refer to TS 38.213, a 3GPP standard document.

[0280] <First pseudo code>

[0281] [Table 5A] [Table 5B] [Table 5C] [Table 5D] [Table 5E]

[0282] The pseudocode is 1,k The values ​​may be summarized as the following stages:

[0283] As a first step, the terminal receives K 1,k Let the value be K, expressed as a slot-granularity. 1,k,slot This step is expressed in the pseudocode above as

number

[0284] In a second step, the UE may check the validity of each PDSCH candidate based on the last symbol of the PDSCH candidate in the SLIV table. In this case, the last symbol of the PDSCH candidate corresponds to sub-slot n. U -K 1,k If it is determined that the PDSCH candidate is not valid, the PDSCH candidate is excluded from the type-1 HARQ-ACK codebook generation process. This step is given in the above pseudocode as follows:

[0285] if subslotLengthForPUCCH-r16 is provided and sub-slot n U -K 1,K is not the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived by row r in slot

number

[0286] R=R\r;

[0287] Through the above two steps, the valid PDSCH candidates may be included in set R. Then, the valid PDSCH candidates in set R can be used to generate a type-1 HARQ-ACK codebook.

[0288] When generating a type-1 HARQ-ACK codebook in this manner, the following problems may occur.

[0289] A terminal may have various capabilities. If a terminal has a specific capability, the terminal can notify the base station of that capability. This is called a capability report. The base station can determine the transmission and reception method to be used by the terminal based on the capability report received from the terminal.

[0290] A terminal can receive one PDSCH per DL slot unless it has a specific capability. In other words, it is not expected that reception of two or more PDSCHs per DL slot is indicated or configured. Therefore, the type-1 HARQ-ACK codebook generated by the terminal includes only the HARQ-ACK of one PDSCH received in one DL slot.

[0291] A terminal may have the capability to receive two or more PDSCHs in one DL slot. In this case, the type-1 HARQ-ACK codebook generated by the terminal includes HARQ-ACKs for one or more PDSCHs received in one DL slot.

[0292] Thus, the type-1 HARQ-ACK codebook generation method may differ depending on the capability, which is shown in pseudocode as follows:

[0293]

number

[0294] One device 1,k Let's assume that at least two values ​​are given. Subslot n U When transmitting a PUCCH including a type-1 HARQ-ACK codebook, the generation of the type-1 HARQ-ACK codebook is as follows: 1,k value (here, K 1,k1 ) to determine the sub-slot nU -K 1,k1 This sub-slot n U -K 1,k1 The DL slot corresponding to the other K can be found. This DL slot is called the first DL slot. 1,k value (here, K 1,k2 ) and sub-slot K 1,k2 This sub-slot n U -K 1,k2 This DL slot is called the second DL slot. The first DL slot and the second DL slot may be the same or different. Here, we will deal with the case where the first DL slot and the second DL slot are the same. For reference, here, sub-slot n U -K 1,k1 The DL slot corresponding to the sub-slot n U -K 1,k1 where sub-slot n U -K 1,k2 The DL slot corresponding to the sub-slot n U -K 1,k2 It may be a DL slot that overlaps with.

[0295] Let's assume that the terminal does not have a specific capability. According to the first pseudocode, the terminal has one K 1,k value (here, K 1,k1 If there is at least one valid PDSCH candidate in the first DL slot corresponding to K, one HARQ-ACK for the PDSCH candidate in the first DL slot is included in the type-1 HARQ-ACK codebook. As mentioned above, even if there are multiple valid PDSCH candidates in the first DL slot, the terminal can only receive a maximum of one PDSCH, so one HARQ-ACK is included in the type-1 HARQ-ACK codebook. 1,k value (here, K 1,k2If there is at least one valid PDSCH candidate in the second DL slot corresponding to DL_1_1_2_3_4_5_6_7, one HARQ-ACK for the PDSCH candidate in the second DL slot is included in the type-1 HARQ-ACK codebook. A problem arises in that the first DL slot and the second DL slot may be the same DL slot, as in the above example. In this case, according to the first pseudocode, the terminal includes two HARQ-ACKs for one DL slot (which is both the first DL slot and the second DL slot) in the type-1 HARQ-ACK codebook. As described above, this is because only one HARQ-ACK needs to be included under the assumption that the terminal can receive only one PDSCH at most in one DL slot. However, since two HARQ-ACKs are included, the size of the type-1 HARQ-ACK codebook increases.

[0296] Referring to Figure 23, K 1,0 The corresponding DL slot for is DL slot 1. The terminal determines that the second PDSCH candidate (B) is a valid PDSCH candidate in DL slot 1. Therefore, the type-1 HARQ-ACK codebook includes one HARQ-ACK for the DL slot. 1,1 The corresponding DL slot for PDSCH candidate A is DL slot 1. The terminal determines that the first PDSCH candidate (A) is a valid PDSCH candidate in DL slot 1. Therefore, the type-1 HARQ-ACK codebook includes one HARQ-ACK for the DL slot. Thus, two or more HARQ-ACKs are included in DL slot 1 in the type-1 HARQ-ACK codebook.

[0297] The present invention discloses a method to solve this problem.

[0298] According to one embodiment of the present invention, the terminal 1,kIf there is at least one valid PDSCH candidate in the DL slot corresponding to the value, one HARQ-ACK for the PDSCH candidate in the DL slot is included in the type-1 HARQ-ACK codebook. In this case, the UE can determine whether to include the HARQ-ACK for the DL slot by checking whether the HARQ-ACK for the DL slot is included in the type-1 HARQ-ACK codebook. That is, if the HARQ-ACK for the DL slot is already included in the type-1 HARQ-ACK codebook, the UE does not include an additional HARQ-ACK for the DL slot in the type-1 HARQ-ACK codebook because it is unnecessary. Conversely, if the HARQ-ACK for the DL slot is not included in the type-1 HARQ-ACK codebook, the UE includes an HARQ-ACK for the DL slot in the type-1 HARQ-ACK codebook because it is necessary.

[0299] In this way, the terminal can include only one HARQ-ACK for one DL slot in the type-1 HARQ-ACK codebook. When the terminal receives a PDSCH in a DL slot, the HARQ-ACK for the PDSCH may be transmitted at a bit position corresponding to the received DL slot in the type-1 HARQ-ACK codebook.

[0300] Referring to Figure 23, K 1,0 The corresponding DL slot for is DL slot 1. The terminal determines that the second PDSCH candidate (B) is a valid PDSCH candidate in DL slot 1. Therefore, the type-1 HARQ-ACK codebook includes one HARQ-ACK for DL ​​slot 1. The next K 1,1The corresponding DL slot for PDSCH candidate (A) is DL slot 1. The UE determines that the first PDSCH candidate (A) is a valid PDSCH candidate in DL slot 1. Here, a valid PDSCH candidate exists, but since a HARQ-ACK for the corresponding DL slot has already been included, it is not included again. If the UE receives the first PDSCH candidate (A) in DL slot 1, it can transmit a HARQ-ACK for the first PDSCH candidate (A) at the HARQ-ACK position included for DL ​​slot 1. If the UE receives a second PDSCH candidate (B) in DL slot 1, it can transmit a HARQ-ACK for the first PDSCH candidate (A) at the HARQ-ACK position included for DL ​​slot 1.

[0301] The above first pseudocode extracts one K1 value from one K1 set, determines valid PDSCH candidates according to the K1 value, and determines the HARQ-ACK bit position between the valid PDSCH candidates. Here, the granularity of the K1 value is subslot. That is, valid PDSCH candidates are determined within one subslot, and the HARQ-ACK bit position between the valid PDSCH candidates is determined. However, since PDSCH is scheduled in slot units rather than subslot units, generating a type-1 HARQ-ACK codebook for each subslot in this manner is inefficient. To improve this, it is necessary to generate a type-1 HARQ-ACK codebook for each slot.

[0302] For example, referring to FIG. 23, the terminal 1,0 For =8, the corresponding DL slot 1 is found and the validity of the two PDSCH candidates (A and B) for DL ​​slot 1 is confirmed. 1,1 For K = 7, the corresponding DL slot 1 is found and the validity of the two PDSCH candidates (A and B) for DL ​​slot 1 is confirmed. That is, K 1,0 The action taken against K 1,1 This is done repeatedly.

[0303] To eliminate such duplicated operations, the terminal 1,k Instead of determining the DL slot for each sub-slot corresponding to K and determining the validity of the PDSCH candidate, 1,k K 1,k,slot Converting said K 1,k,slot It is preferable to determine the DL slot by the value and determine the validity of the PDSCH candidate.

[0304] According to an embodiment of the present invention, the terminal uses a K1 value (hereinafter referred to as K 1,k ) is the slot level K1 value (hereafter referred to as K 1,k,slot ) More specifically, the slot-level K1 value may be determined as follows:

[0305]

number

[0306] The above K 1,k,slot The set of values ​​is called K 1,slot For reference, if there are two or more K 1,k is the same K 1,k,slot Conversely, K 1,slot One K in the set 1,k,slot Multiple K values 1,k,slot The values ​​can correspond.

[0307] Referring again to FIG. 22, K 1,k,slot can be found as follows:

[0308]

number

[0309] Therefore, K 1,slot ={1,0}.

[0310] The terminal is 1,slot K of the set 1,k,slotThe type-1 HARQ-ACK codebook can be generated in descending order of the value of K. 1,slot From the set, the largest K 1,k,slot Take out the value of K 1,k,slot Then, valid PDSCH candidates for the DL slots corresponding to K 1,slot The second largest K from the set 1,k,slot Take out the value of K 1,k,slot This operation can determine valid PDSCH candidates for the DL slots corresponding to K 1,slot The smallest K from the set 1,k,slot Take out the value of K 1,k,slot This may continue until a valid PDSCH candidate for the DL slot corresponding to .

[0311] The terminal is the K selected earlier. 1,k,slot The validity of the PDSCH candidate to be included in the type-1 HARQ-ACK codebook can be checked according to the value. If valid, the PDSCH candidate can be included; if not, the PDSCH candidate can be excluded. This process can be determined based on whether the last symbol (ending point) of the PDSCH candidate is included in a specific subslot. Here, the specific slot is as follows: K 1,k,slot K corresponding to the value 1,k Value K 1,k1 ,K 1,k2 ,..., then sub-slot n U -K 1,k1 , sub-slot n U -K 1,k2 ,...is.

[0312] Referring to Figure 23, K 1,0,slot If the terminal selects =1, the PDSCH candidate in DL slot 1 is U -K 1,0 = Subslot 4 and Subslot n U -K 1,1 = It must be determined whether it is valid for subslot 5. For reference, K 1,0,slot =1 is K 1,0 =8 and K 1,123 corresponds to ∑ = 7. In the example of FIG. 23, let us assume that two PDSCH candidates are configured for the terminal. The first PDSCH candidate is designated as "A" in FIG. 23, and the second PDSCH candidate is designated as "B" in FIG. 23. The terminal determines whether the last symbol (ending point) of each PDSCH candidate is in subslot n U -K 1,0 = Subslot 4 or Subslot n U -K 1,1 If it is determined that the PDSCH candidate is included, it is determined that the PDSCH candidate is valid. If not, it is determined that the PDSCH candidate is invalid. The last symbol (ending point) of the first PDSCH candidate (A) is in subslot n. U -K 1,1 = subslot 5. Therefore, it can be determined that the first PDSCH candidate (A) is valid. The last symbol (end point) of the second PDSCH candidate (B) is included in subslot n U -K 1,0 = included in subslot 4. Therefore, the second PDSCH candidate (B) can be determined to be valid.

[0313] Referring to Figure 23, K 1,1,slot = 0, the terminal selects the PDSCH candidate for DL ​​slot 2 as the PDSCH candidate for subslot n U -K 1,2 = Subslot 8 and Subslot n U -K 1,3 = It must be determined whether it is valid for subslot 9. For reference, K 1,1,slot =0 is K 1,2 =4 and K 1,3 = 3. The terminal determines that the last symbol (end point) of each PDSCH candidate is in subslot n U -K 1,2 = Subslot 8 or Subslot n U -K 1,3If it is determined that the PDSCH candidate is included, it is determined that the PDSCH candidate is valid. If not, it is determined that the PDSCH candidate is invalid. The last symbol (ending point) of the first PDSCH candidate (A) is in subslot n. U -K 1,2 = subslot 8. Therefore, the first PDSCH candidate (A) can be determined to be valid. The last symbol (end point) of the second PDSCH candidate (B) is included in subslot n U -K 1,2 = included in subslot 8. Therefore, the second PDSCH candidate (B) can be determined to be valid.

[0314] More specifically, it is effective if the following is satisfied:

[0315] <Validity conditions>

[0316] if subslotLengthForPUCCH-r16 is provided and at least one of sub-slot n U -K 1,K is the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived by row r in slot

number

[0317] where n U,slot is the sub-slot n U is the index of the slot corresponding to

number

[0318] It is not valid if the following is true:

[0319] <Invalid conditions>

[0320] if subslotLengthForPUCCH-r16 is provided and all of sub-slot n U -K 1,K is not the last UL sub-slot overlapping with the DL slot of the PDSCH time resource derived by row r in slot

number

[0321] If the last symbol of a PDSCH candidate is not included in all sub-slots, it will not be valid.

[0322] With this modification, the existing Rel-15 / 16 pseudocode for generating type-1 HARQ-ACK can be applied to sub-slot configuration with minimal modification. More specific pseudocode is as follows. For reference, all variables here refer to TS 38.213, a 3GPP standard document.

[0323] <Second pseudo code>

[0324] [Table 6A] [Table 6B] [Table 6C] [Table 6D] [Table 6E]

[0325] In an NR wireless communication system, a terminal can transmit HARQ-ACK information using a semi-static HARQ-ACK codebook. When a semi-static HARQ-ACK codebook is used, a base station can use RRC signals to configure the length of the HARQ-ACK codebook and which PDSCH ACK / NACK each bit of the HARQ-ACK codebook indicates. Therefore, the base station does not need to signal information required for HARQ-ACK codebook transmission every time HARQ-ACK codebook transmission is required. A set of PDSCHs for which ACK / NACK is indicated by the semi-static HARQ-ACK codebook is called a PDSCH candidate set. Hereinafter, a method by which a terminal determines a PDSCH candidate set will be described with reference to FIG. 24.

[0326] The terminal determines the PDSCH candidate set based on information signaled from the base station. In this case, the information signaled from the base station may include K1. K1 represents the difference between the last slot in which the PDSCH is received or scheduled and the slot in which the PUCCH is transmitted. Fallback DCI (DCI format 1_0) may indicate the K1 value as one of 1, 2, 3, 4, 5, 6, 7, or 8. Non-fallback DCI (DCI format 1_1 or 1_2) may indicate the K1 value as one of up to eight values ​​set by RRC signaling. In addition, the information signaled from the base station may include K0 and a combination of the start symbol of the PDSCH in the slot and the length of the PDSCH. In this case, K0 represents the difference between the slot in which the PDCCH is received and the slot in which the PDSCH scheduled by the PDCCH is received. In addition, the combination of the start symbol of the PDSCH in the slot and the length of the PDSCH may be encoded in the form of an SLIV (start and length indicator value). The base station can signal up to 16 combinations of K0 value and PDSCH starting symbol and length. The terminal can obtain one of the 16 combinations in the DCI scheduling the PDSCH. The terminal can obtain information about the time domain in which the PDSCH is received from the K0 value indicated by the DCI and the PDSCH starting symbol and length in the slot.

[0327] Furthermore, the information signaled from the base station may include a semi-static DL / UL configuration. The semi-static DL / UL configuration represents symbol configuration information of a slot configured by a cell-specific RRC signal or a UE-specific RRC signal. Specifically, it may indicate whether each symbol included in a slot is a DL symbol, a UL symbol, or a flexible symbol. The UE may determine a PDSCH candidate set based on whether any one of the symbols to which a PDSCH is assigned corresponds to an UL symbol. This is because PDSCH reception is not possible for symbols corresponding to UL symbols. In a specific embodiment, if any one of the symbols to which a PDSCH is assigned corresponds to an UL symbol, the UE may not include the corresponding PDSCH in the PDSCH candidate set. If all the symbols to which a PDSCH is assigned do not correspond to UL symbols, the UE may include the corresponding PDSCH in the PDSCH candidate set.

[0328] In addition, the information signaled from the base station may include information regarding the configuration of a CORESET and a search space, which may indicate at which slot and at which position a PDCCH may be received.

[0329] The information signaled from the base station may also include a PDSCH repetition value. The base station can receive the same PDSCH the number of times indicated by the PDSCH repetition value while receiving the PDSCH for each slot. In this case, the terminal can start receiving the PDSCH at the same symbol position in each slot. The terminal can also receive the PDSCH using the same length in each slot. The base station can set the PDSCH repetition value to one of 1, 2, 4, and 8 using an RRC signal. A PDSCH repetition value greater than 1 can indicate the use of slot aggregation. When repeated reception of the PDSCH is configured to be repeated in multiple slots, the terminal can determine whether a condition for including the PDSCH in a PDSCH candidate set is met based on whether PDSCH reception is possible in all slots in which the PDSCH is received. Specifically, if the terminal determines that PDSCH reception is impossible in all slots in which PDSCH repetition is indicated, the terminal may not include the PDSCH in the PDSCH candidate set. In yet another embodiment, if PDSCH reception is possible in at least one of the slots indicated as receiving a PDSCH, the terminal may include the PDSCH in the PDSCH candidate set.

[0330] The terminal includes each combination of K1 values, K0, and PDSCH candidates indicated by SLIV in the PDSCH candidate set based on whether the PDSCH candidate indicated by SLIV for each of multiple K1 values ​​and K0 is valid. It can be determined whether the PDSCH candidate indicated by SLIV for each of multiple K1 values ​​and K0 is valid. If the combination of the K1 value, K0, and PDSCH candidate indicated by SLIV is valid, the terminal can include the combination of the K1 value, K0, and PDSCH candidate indicated by SLIV in the PDSCH candidate set. For ease of explanation, the slot in which the PUCCH is transmitted is called the nth slot. The n-K1th slot, n-K1-1th slot, ..., and n-K1-(N repIf any of the symbols in the slots indicated by the SLIV to be assigned a PDSCH corresponds to an UL symbol, the terminal can determine that the PDSCH candidate indicated by the SLIV is not valid for the K1 and K0 values. rep indicates the number of slots in which the PDSCH is repeatedly received. rep may be set by RRC signaling, and N rep = 1. In this case, if any one of the symbols indicated by the SLIV to be assigned a PDSCH in the n-K1th slot corresponds to an UL symbol, the terminal can determine that the PDSCH candidate indicated by the SLIV is not valid for the K1 value and K0. Also, n-K1-(N rep -1) If there is no search space in the K0-th slot, the terminal can determine that the PDSCH candidate indicated by the corresponding SLIV is not valid for the corresponding K1 value and K0. As described above, when PDSCH repetition is not used, N rep = 1. Specifically, the n-K1-th slot, the n-K1-1-th slot, ..., and the n-K1-(N rep In any one of the n-K1-(N-1)th slots, all of the symbols to which the SLIV indicates that the PDSCH is assigned do not correspond to UL symbols, and rep -1) If there is a search space in the K0-th slot, the terminal can determine that the PDSCH candidate indicated by the SLIV is valid for the K1 value and K0. If the terminal determines that the PDSCH candidate indicated by the SLIV value is not valid, the terminal does not need to include the combination of the K1 value, K0, and the PDSCH candidate indicated by the SLIV in the PDSCH candidate set.

[0331] FIG. 24 illustrates determining whether a PDSCH candidate indicated by an SLIV signaled to a terminal according to an embodiment of the present invention is included in a PDSCH candidate set according to K1 and K0.

[0332] In the example of FIG. 24, the n-K1th slot, the n-K1-1th slot, ..., and the n-K1-(N rep In any of the (-1)th slots, any one of the symbols indicated by the SLIV to be assigned a PDSCH in that slot corresponds to an UL symbol. Therefore, the terminal determines that the PDSCH candidate indicated by the SLIV for that K1 value and K0 is not valid. The terminal does not include the combination of that K1 value and the PDSCH candidate indicated by K0 and the SLIV in the PDSCH candidate set.

[0333] The terminal combines two combinations into one combination based on whether a PDSCH candidate having a K1 value included in the PDSCH candidate set and a combination of K0 and SLIV overlaps with a PDSCH candidate having another K1 value and a combination of K0 and SLIV included in the PDSCH candidate set by at least one symbol in at least one slot. The terminal can determine whether a PDSCH candidate having a K1 value included in the PDSCH candidate set and a combination of K0 and SLIV overlaps with a PDSCH candidate having another K1 value and a combination of K0 and SLIV included in the PDSCH candidate set by at least one symbol in at least one slot. The terminal can combine two combinations into one combination if a PDSCH candidate having a K1 value included in the PDSCH candidate set and a PDSCH candidate having a combination of K0 and SLIV with a different K1 value overlaps with at least one symbol in at least one slot. In a specific embodiment, when the PDSCH candidate set includes N combinations, the terminal can determine whether the PDSCH candidate of the nth combination overlaps with each PDSCH candidate of the combinations m=n+1,..., N. In this case, the terminal can perform operations related to overlap determination sequentially from n=0 to n=N-1.

[0334] The terminal can determine the position of the HARQ-ACK information of a PDSCH in the semi-static HARQ-ACK codebook based on the position of the last symbol of the PDSCH included in the PDSCH candidate set. Specifically, the terminal can determine the position of the bit indicating the ACK / NACK of the PDSCH in the HARQ-ACK codebook according to the position of the last symbol of the PDSCH included in the PDSCH candidate set. Specifically, the HARQ-ACK information of a PDSCH whose last symbol is earlier may also be located earlier. For example, if the last symbol of a first PDSCH is earlier than the last symbol of a second PDSCH, the bit indicating the ACK / NACK of the first PDSCH may be located earlier in the HARQ-ACK codebook than the bit indicating the ACK / NACK of the second PDSCH.

[0335] The terminal can multiplex different UCI types (HARQ-ACK, SR, or CSI (part 1 or part 2)) onto the PUCCH and transmit them. The terminal can determine the maximum number of bits that can be transmitted on the PUCCH. This can be set by the base station or can be determined using at least one of the maximum code rate, the number of PUCCH symbols, the number of PRBs, and the number of DM-RS symbols set for the PUCCH. If the number of UCI bits is greater than the maximum number of bits that can be transmitted on the PUCCH, the terminal cannot transmit all UCI and may not need to transmit some UCI types.

[0336] For example, CSI part 2 may be excluded. If the number of UCI bits is still greater than the maximum number of bits even after CSI part 2 is excluded, CSI part 1 may be excluded. If the number of UCI bits is still greater than the maximum number of bits even after CSI part 1 is excluded, SR may be excluded. If the number of UCI bits is still greater than the maximum number of bits even after SR is excluded, a process of dropping part or all of the HARQ-ACK or bundling part or all of the HARQ-ACK may be performed. Hereinafter, the present invention relates to a method for reducing the number of bits of the HARQ-ACK.

[0337] As described above, the size (i.e., the bit size) of the semi-static HARQ-ACK codebook is determined by signaling from the base station. Since this size does not change according to the number of PDSCHs actually received by the terminal, even if the terminal fails to receive any PDSCH, the size of the semi-static HARQ-ACK codebook transmitted by the terminal remains the same.

[0338] There may be cases where the terminal cannot transmit a given semi-static HARQ-ACK codebook in a specific situation. In this case, the terminal can transmit only the HARQ-ACK bits of some of the PDSCHs in the semi-static HARQ-ACK codebook, or can combine and transmit the information of the HARQ-ACK bits of some or all of the PDSCHs in the semi-static HARQ-ACK codebook. Here, transmitting only the HARQ-ACK bits of some of the PDSCHs is called dropping, and combining and transmitting the information of some or all of the bits is called bundling.

[0339] Dropping means transmitting only the HARQ-ACK bits of some of the PDSCHs in the semi-static HARQ-ACK codebook and not transmitting the HARQ-ACK bits of the remaining PDSCHs. Through this process, the terminal can reduce the size (i.e., the bit size) of the semi-static HARQ-ACK codebook. For example, let the size of the semi-static HARQ-ACK codebook be A bits. If the bit size that the terminal can transmit is B bits (B < A), then the terminal must select and transmit only B bits in the semi-static HARQ-ACK codebook. For reference, the terminal can select bits smaller than B. Also, although described as bits here, this may be interpreted in place of the number of PDSCHs.

[0340] The problem to be solved by the present invention relates to a method for determining which PDSCH's HARQ-ACK bits to transmit during dropping.

[0341] Bundling is a method of combining and transmitting HARQ-ACK bit information of some or all PDSCHs in a semi-static HARQ-ACK codebook, and the combining method may be as follows: If all HARQ-ACK bits to be combined are ACK, the combined HARQ-ACK bits are ACK. Otherwise, the combined HARQ-ACK bits are NACK. In other words, ACK is represented by a binary 1 (or "true") and NACK is represented by a binary 0 (or "false"). The combined HARQ-ACK bit may be determined as the binary product of the HARQ-ACK bits to be combined.

[0342] The problem to be solved by the present invention relates to a method for determining which PDSCH's HARQ-ACK information should be combined during bundling.

[0343] The first to fourth embodiments are applicable to a case where a terminal receives a PDSCH in one cell. The first embodiment is applicable to a case where a terminal receives a PDSCH in multiple cells (that is, in the case of CA (carrier aggregation)).

[0344] As a first embodiment, if the number of HARQ-ACK bits (here, A bits) included in the semi-static HARQ-ACK codebook is greater than the number of bits (here, B bits) that the terminal can transmit, the terminal does not need to transmit the entire semi-static HARQ-ACK codebook. That is, if the number of bits is even one bit less than the number of transmittable bits, the terminal does not need to transmit the semi-static HARQ-ACK codebook.

[0345] As a second embodiment, the terminal may transmit some bits of the semi-static HARQ-ACK codebook and not transmit the remaining bits. At this time, the selection of the some bits to be transmitted may be determined based on the position of the bits in the semi-static HARQ-ACK codebook. Preferably, the some bits to be transmitted may be the bits arranged at the previous position in the semi-static HARQ-ACK codebook.

[0346] For example, let the size of the semi-static HARQ-ACK codebook be A bits. If the bit size that the terminal can transmit is B bits (B < A), the terminal can select and transmit only the first B bits in the semi-static HARQ-ACK codebook.

[0347] FIG. 25 is a diagram showing a method for reducing the HARQ-ACK size according to an embodiment of the present invention.

[0348] Referring to FIG. 25, K1 has two values (K1(1) and K1(2)) and is one cell. According to the semi-static HARQ-ACK codebook generation method, 4 HARQ-ACK bits of PDSCH are generated by each K1 value. That is, by the K1(1) value, 4 HARQ-ACK bits of PDSCH, [b0 b1 b2 b3], are generated, and by the K1(2) value, 4 HARQ-ACK bits of PDSCH, [b4 b5 b6 b7], are generated. Then, the terminal transmits [b0 b1 b2 b3 b4 b5 b6 b7] in the semi-static HARQ-ACK codebook.

[0349] In the embodiment of FIG. 25, if the terminal has to select and transmit only B = 5 bits, the terminal has to select 5 bits out of the A = 8 bits. According to the second embodiment, the terminal can select the previous 5 bits out of the A = 8 bits. This may be [b0 b1 b2 b3 b4].

[0350] In the second embodiment, it is expressed as a method of selecting some NACK bits, but this may be applied in place of some of the PDSCHs. More specifically, let the semi-static HARQ-ACK codebook include the HARQ-ACK bits of A PDSCHs. The number of HARQ-ACK bits corresponding to each PDSCH may be the same or different. Also, the number of HARQ-ACK bits corresponding to each PDSCH may be 1 bit or a plurality of bits. The terminal can select the bits for transmitting the HARQ-ACK bits of the PDSCH arranged at the previous position in the semi-static HARQ-ACK codebook. At this time, when any one of the PDSCHs' HARQ-ACK bits is partially included in the semi-static HARQ-ACK codebook but not all, all of the HARQ-ACK bits of the said PDSCH are excluded.

[0351] For example, let the size of the semi-static HARQ-ACK codebook be A bits. If the bit size that the terminal can transmit is B bits (B < A), the terminal selects the first B bits in the semi-static HARQ-ACK codebook, but checks whether the HARQ-ACK bit of the last PDSCH among the PDSCHs corresponding to the B HARQ-ACKs is included in the said B bits. If it is included, the semi-static HARQ-ACK codebook composed of the said B bits can be transmitted. If it is not included, the HARQ-ACK bit of the last PDSCH can be excluded in the semi-static HARQ-ACK codebook composed of the said B bits.

[0352] As a third embodiment, the terminal can determine the bits to be transmitted based on the slot index in the semi-static HARQ-ACK codebook. Here, the slot index may be determined by a K1 value. The terminal transmits the HARQ-ACK bits corresponding to the slots with a lower (earlier in time) index and does not have to transmit the HARQ-ACK bits corresponding to the slots with a higher (later in time) index. For reference, when the K1 value is large, it is an earlier slot in time.

[0353] For example, let the size of the semi-static HARQ-ACK codebook be A bits. If the bit size that the terminal can transmit is B bits (B < A), the terminal sequentially calculates the length of the HARQ-ACK bits in the semi-static HARQ-ACK codebook starting from the earliest slot. When the calculated length of the HARQ-ACK bits is smaller than B, the terminal calculates the length of the HARQ-ACK bits including the next slot. If the length of the HARQ-ACK bits including the next slot is larger than B, it is possible to determine the HARQ-ACK bits to be transmitted including only the HARQ-ACK bits of the earlier slots excluding the HARQ-ACK bits of that slot.

[0354] FIG. 26 is a diagram showing a method for reducing the HARQ-ACK size according to an embodiment of the present invention.

[0355] Referring to FIG. 26, if the terminal has to select and transmit only B = 5 bits, the terminal calculates the HARQ-ACK bits of the earliest slot (here, 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 slot can be calculated. The HARQ-ACK bits calculated including the next slot (here, slot n-K1(2)) are [b0 b1 b2 b3 b4 b5 b6 b7], which is 8 bits. Therefore, the terminal can determine that the HARQ-ACK bits calculated in the previous slot (here, slot n-K1(1)) with [b0 b1 b2 b3] are the HARQ-ACK bits to be transmitted.

[0356] In the second and third embodiments, the terminal transmits only the HARQ-ACK of the PDSCH in a specific slot (here, slot n-K1(1)), and cannot transmit the HARQ-ACK of the PDSCH in other slots (here, slot n-K1(2)). Therefore, even if the base station schedules PDSCHs in different slots from each other, a problem may occur that the HARQ-ACK of some slots is not transmitted. An embodiment for solving this is disclosed.

[0357] As a fourth embodiment, the terminal can distribute transmittable bits among slots and select bits to be transmitted. More specifically, the terminal determines bits to be transmitted among slots according to the K1 value in the semi-static HARQ-ACK codebook.

[0358] For example, if the number of bits that a terminal can transmit is A bits and the K1 value is K, the number of bits to transmit in each slot may be determined based on A and the K1 value. For example, it can be determined based on A / K. If A / K is not an integer, at least one value of ceil(A / K), round(A / K), or floor(A / K) can be determined as the number of bits to transmit in each slot. Once the number of bits that can be transmitted in each slot is determined, the terminal can determine the bits that should not be transmitted and the bits that should be transmitted in each slot. Preferably, within a slot, the terminal can determine the earlier bits as the bits that should be transmitted, and the later bits as the bits that should be transmitted.

[0359] FIG. 27 is a diagram illustrating a method for reducing the HARQ-ACK size according to one embodiment of the present invention.

[0360] Referring to Figure 27, if a terminal must select and transmit only B = 4 bits, the terminal can transmit only two bits in each slot (slot n-K1(1) and slot n-K1(2)). Therefore, it can select only the first two bits in each slot and transmit [b0 b1 b4 b5].

[0361] Although the above embodiment has been described with respect to one cell, it may be interpreted as a method in which the slot in the above embodiment is replaced with a cell, and some of the HARQ-ACK bits of different cells are selected and transmitted.

[0362] When a terminal is configured for PDSCH reception in two or more cells (i.e., in the case of carrier aggregation (CA)), the following can be considered.

[0363] First, in the case of CA, a UE may be configured with a different reception method for each cell. Here, the reception method may include TB-based PDSCH reception and CBG-based PDSCH reception, or reception including 1 TB per PDSCH and reception including 2 TB per PDSCH. If the number of bits of the semi-static HARQ-ACK codebook is greater than the number of bits that the UE can transmit, different cells have different reception methods, so the following method is required to take this into consideration.

[0364] 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 that CBG-based PDSCH reception in the cell is TB-based PDSCH reception. Here, ACK / NACK for TB-based PDSCH reception is determined depending on whether TB-CRC is successful. That is, a 1-bit HARQ-ACK is generated per TB. Alternatively, the 1-bit per TB generated for TB-based PDSCH reception can be obtained by bundling N_CBG-bit ACK / NACKs generated for CBG-based PDSCH reception. If the size of the semi-static HARQ-ACK codebook generated assuming TB-based PDSCH reception is less than or equal to the number of transmittable bits (here, B bits), the UE can transmit the semi-static HARQ-ACK codebook. If the size of the semi-static HARQ-ACK codebook generated assuming the TB-based PDSCH reception is greater than the number of transmittable bits (here, B bits), the UE cannot transmit the semi-static HARQ-ACK codebook. In this case, dropping or bundling of additional HARQ-ACK bits is required, as will be described later.

[0365] FIG. 28 is a diagram illustrating a method for reducing the HARQ-ACK size in a carrier aggregation situation according to one embodiment of the present invention.

[0366] Referring to (a) and (b) of FIG. 28, a terminal is configured to receive PDSCH in three cells (CC#0, CC#1, CC#2), and four K1 values ​​(K1(1), K1(2), K1(3), K1(4)) are configured. One cell (CC#0) is configured to receive TB-based PDSCH reception and 1 TB per PDSCH, another cell (CC#1) is configured to receive TB-based PDSCH reception and 2 TB per PDSCH, and another cell (CC#2) is configured to receive CBG-based PDSCH reception and 1 TB per PDSCH. According to the first method, the terminal determines the number of HARQ-ACK bits (M 21 , M 22 , M 23 , or M 34 ), a semi-static HARQ-ACK codebook is generated assuming TB-based HARQ-ACK. The resulting number of HARQ-ACK bits (N 21 , N 22 , N 23 , or N 24 ) is 1 bit per PDSCH.

[0367] As a second method, the UE can generate a semi-static HARQ-ACK codebook for each cell configured for CBG-based PDSCH reception, assuming TB-based PDSCH reception, and determine whether to transmit the code. The UE generates a semi-static HARQ-ACK codebook for one cell configured for CBG-based PDSCH reception, assuming TB-based PDSCH reception, and transmits the semi-static HARQ-ACK codebook if the value of the semi-static HARQ-ACK codebook is less than or equal to the number of bits that the UE can transmit. If the value of the semi-static HARQ-ACK codebook is greater than the number of bits that the UE can transmit, the UE generates a semi-static HARQ-ACK codebook for another cell configured for CBG-based PDSCH reception, assuming TB-based PDSCH reception, and transmits the semi-static HARQ-ACK codebook if the value of the semi-static HARQ-ACK codebook is less than or equal to the number of bits that the UE can transmit. If this process is performed for all cells configured for CBG-based PDSCH reception and the size of the semi-static HARQ-ACK codebook is still greater than the number of bits that the terminal can transmit, the semi-static HARQ-ACK codebook cannot be transmitted. In this case, dropping or bundling of additional HARQ-ACK bits is required, as will be described later.

[0368] As a third method, if 2TB reception per PDSCH is configured in the cell, the UE bundles 2TB HARQ-ACK bits in the cell to generate one bit (this bundling is called spatial bundling) and generates a semi-static HARQ-ACK codebook based on the bit. If the size of the semi-static HARQ-ACK codebook generated based on the spatial bundling bits is less than or equal to the number of transmittable bits (here, B bits), the UE can transmit the semi-static HARQ-ACK codebook. If the size of the semi-static HARQ-ACK codebook generated based on the spatial bundling bits is greater than the number of transmittable bits (here, B bits), the UE cannot transmit the semi-static HARQ-ACK codebook. In this case, dropping or bundling of additional HARQ-ACK bits is required, as will be described later.

[0369] Referring to (a) and (c) of FIG. 28, according to the third method, the terminal determines the number of HARQ-ACK bits (L 21 , L 22 , L 23 , or L 34 ), the 2TB ACK / NACKs of one PDSCH can be spatially bundled. The resulting number of HARQ-ACK bits (N 21 , N 22 , N 23 , or N 24 ) is 1 bit per PDSCH.

[0370] As a fourth method, similar to the second method, the terminal can perform spatial bundling sequentially among the cells configured for 2TB reception per PDSCH, one by one, to generate a semi-static HARQ-ACK codebook and determine whether to transmit.

[0371] The first and third methods can be combined to form the following preferred embodiment. In this preferred embodiment, the UE generates a semi-static HARQ-ACK codebook assuming TB-based PDSCH reception in a cell configured for CBG-based PDSCH reception, and checks whether the semi-static HARQ-ACK codebook can be transmitted. If transmission is not possible, the UE further performs spatial bundling and checks whether the generated semi-static HARQ-ACK codebook can be transmitted.

[0372] The specific operation is as follows: If 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 CBG-based PDSCH reception in the cell as TB-based PDSCH reception. If the size of the semi-static HARQ-ACK codebook generated by the UE assuming TB-based PDSCH reception is less than or equal to the number of transmittable bits (here, B bits), the UE can transmit the semi-static HARQ-ACK codebook. Otherwise, the UE further performs spatial bundling to bundle 2TB HARQ-ACK bits in the cell to generate 1 bit, and generates a semi-static HARQ-ACK codebook based on the bit. If the size of the semi-static HARQ-ACK codebook generated by the UE based on the spatially bundled bits is less than or equal to the number of transmittable bits (here, B bits), the UE can transmit the semi-static HARQ-ACK codebook. If the size of the semi-static HARQ-ACK codebook generated based on the spatially bundled bits is greater than the number of transmittable bits (here, B bits), the terminal cannot transmit the semi-static HARQ-ACK codebook. In this case, dropping or bundling of additional HARQ-ACK bits is required, as will be described later.

[0373] Referring to (a), (b), and (d) of FIG. 28, first, by the first method, the terminal determines the number of HARQ-ACK bits (M 21 , M 22 , M 23 , or M 34 ), a semi-static HARQ-ACK codebook is generated assuming TB-based HARQ-ACK. The resulting number of HARQ-ACK bits (N 21 , N 22 , N 23 , or 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 terminal can transmit, the terminal further implements a third method. By the third method, the terminal determines the number of HARQ-ACK bits (L) generated by the 2TB reception setting per PDSCH of CC#1. 21 , L 22 , L 23 , or L 34 ), the 2TB ACK / NACKs of a PDSCH can be spatially bundled. The resulting number of HARQ-ACK bits (N 21 , N 22 , N 23 , or N 24 ) is 1 bit per PDSCH. The semi-static HARQ-ACK codebooks generated by the first and third methods include 1 bit of HARQ-ACK per PDSCH.

[0374] According to the first to fourth methods, the terminal can have the same one HARQ-ACK bit per PDSCH in each cell. After the first to fourth methods, if the size of the semi-static HARQ-ACK codebook is greater than the number of bits that the terminal can transmit, the terminal needs to drop or bundle additional HARQ-ACK bits. For reference, the dropping or bundling of HARQ-ACK bits described below may also be applied to the first to fourth methods. Unless otherwise specified, the dropping or bundling of HARQ-ACK bits described below can also be applied when the first to fourth methods are not used (i.e., when the semi-static HARQ-ACK codebook includes multiple HARQ-ACK bits per PDSCH).

[0375] As a fifth embodiment, the UE may generate a semi-static HARQ-ACK codebook including HARQ-ACK bits of some cells and transmit the semi-static HARQ-ACK codebook, where the some cells may be selected based on cell indexes.

[0376] FIG. 29 is a diagram illustrating a method for reducing HARQ-ACK size in a carrier aggregation situation according to one embodiment of the present invention.

[0377] Referring to (a) of FIG. 29, if a terminal is configured to receive PDSCH in three cells (CC#0, CC#1, and CC#2), the terminal can generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of CC#0. However, the terminal may need to generate a semi-static HARQ-ACK codebook including the number of bits (N 01 +N 02 +N 03 +N 04 ) is greater than the number of bits that the terminal can transmit, the terminal cannot transmit the semi-static HARQ-ACK codebook. In this case, dropping or bundling needs to be performed within one cell. The methods of the above embodiments 1 to 4 can be applied to this. Then, the terminal determines the number of bits (N 01 +N 02 +N03 +N 04 ) is less than or equal to the number of bits that the terminal can transmit, the terminal can transmit the semi-static HARQ-ACK codebook. Furthermore, the terminal can generate a semi-static HARQ-ACK codebook including the HARQ-ACK bits of the cell (CC#1) having 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 less than or equal to the number of bits that the terminal can transmit, the terminal can transmit the 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 terminal can transmit, a semi-static HARQ-ACK codebook generated in cells up to the previous index excluding the cell (CC#1) can be generated.

[0378] In a sixth embodiment, the UE may generate a semi-static HARQ-ACK codebook including HARQ-ACK bits corresponding to some slots and transmit the semi-static HARQ-ACK codebook, where some slots may be selected based on the K1 value.

[0379] Referring to (b) of FIG. 29, when a terminal is configured to receive a PDSCH in four slots (n-K1(1), n-K1(2), n-K1(3), n-K1(4)) determined by four K1 values ​​(K1(1), K1(2), K1(3), K1(4)), the terminal can generate a semi-static HARQ-ACK codebook including the HARQ-ACK bit of the first slot (n-K1(1)). However, ... 01 +N11 +N 21 ) is greater than the number of bits that the terminal can transmit, the terminal cannot transmit the semi-static HARQ-ACK codebook. 01 +N 11 +N 21 ) is less than or equal to the number of bits that the terminal can transmit, the terminal can transmit the semi-static HARQ-ACK codebook. Furthermore, the terminal can generate a semi-static HARQ-ACK codebook including HARQ-ACK bits for the next slot (n-K1(2)). If the number of bits of the semi-static HARQ-ACK codebook (N 01 +N 11 +N 21 +N 02 +N 12 +N 22 ) is less than or equal to the number of bits that the terminal can transmit, the terminal can transmit the 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 terminal can transmit, a semi-static HARQ-ACK codebook generated in previous slots excluding the slot (n-K1(2)) can be generated.

[0380] In the fifth and sixth embodiments, the terminal excludes the HARQ-ACK bit of a specific cell or excludes the HARQ-ACK bit of a specific slot. However, when the terminal excludes the HARQ-ACK bit of a specific cell, it does not need to exclude the HARQ-ACK bit of all slots of that cell. Also, when the terminal excludes the HARQ-ACK bit of a specific slot, it does not need to exclude the HARQ-ACK bit of all cells in that slot.

[0381] As in the fifth embodiment, the terminal can generate a semi-static HARQ-ACK codebook consisting of HARQ-ACK bits for some cells. In this case, when adding the HARQ-ACK bit for a specific cell to the semi-static HARQ-ACK codebook, the terminal can sequentially add the HARQ-ACK bit for each slot of the specific cell. This addition process can be performed by adding all HARQ-ACK bits for all slots of the specific cell, or by adding the HARQ-ACK bit for any slot until the number of bits that the terminal can transmit is exceeded. If adding the HARQ-ACK bit for any slot exceeds the number of bits that the terminal can transmit, the terminal can transmit a semi-static HARQ-ACK codebook that includes the HARQ-ACK bits for slots prior to that slot. This method can be referred to as the K1 value first, CC second method.

[0382] Referring to (c) of FIG. 29, the terminal can generate a semi-static HARQ-ACK codebook configured with HARQ-ACK bits of CC#0. This semi-static HARQ-ACK codebook is 01 +N 02 +N 03 +N 04 The HARQ-ACK bits of the next cell, CC#1, can be added to the semi-static HARQ-ACK codebook in the order of the slots of cell CC#1. First, the HARQ-ACK bits of the slot (n-K1(1)) corresponding to the K1(1) value (N 11It can be determined whether to add a HARQ-ACK bit (n-K1(4)) to the semi-static HARQ-ACK codebook. If the number of bits in the semi-static HARQ-ACK codebook to which the HARQ-ACK bit has been added is less than or equal to the number of bits that the terminal can transmit, the HARQ-ACK bit can be added to the semi-static HARQ-ACK codebook. Then, it can be determined whether to add a HARQ-ACK bit for the next slot (n-K1(2)). If the number of bits in the semi-static HARQ-ACK codebook to which the HARQ-ACK bit has been added is greater than the number of bits that the terminal can transmit, the HARQ-ACK bit is not added to the semi-static HARQ-ACK codebook. In this way, it can be determined whether to add a HARQ-ACK bit for the last slot (n-K1(4)).

[0383] As in the sixth embodiment, the terminal can generate a semi-static HARQ-ACK codebook consisting of HARQ-ACK bits for some slots. In this case, when adding the HARQ-ACK bit for a specific slot to the semi-static HARQ-ACK codebook, the terminal can sequentially add the HARQ-ACK bit for each cell in that specific slot. This addition process can be performed until all HARQ-ACK bits for all cells in that specific slot are added, or until the number of HARQ-ACK bits for any cell exceeds the number of bits that the terminal can transmit. If the number of bits that the terminal can transmit is exceeded after adding the HARQ-ACK bit for any cell, the terminal can transmit a semi-static HARQ-ACK codebook that includes the HARQ-ACK bits for the previous cell of that cell. This method can be referred to as a CC first, K1 value second method.

[0384] Referring to (d) of FIG. 29, the terminal can generate a semi-static HARQ-ACK codebook configured with the HARQ-ACK bits of slot n-K1(2). This semi-static HARQ-ACK codebook is 01 +N 11 +N 21 +N 02 +N 12 +N 22The HARQ-ACK bits of the next slot, slot n-K1(3), can be added to the semi-static HARQ-ACK codebook in the order of the cells in slot n-K1(3). First, the HARQ-ACK bits of the cell (CC#0) with the lowest index (N 03 It can be determined whether to add the HARQ-ACK bit of the cell with the next index (CC#1) to the semi-static HARQ-ACK codebook. If the number of bits in the semi-static HARQ-ACK codebook to which the HARQ-ACK bit has been added is less than or equal to the number of bits that the terminal can transmit, the HARQ-ACK bit can be added to the semi-static HARQ-ACK codebook. Then, it can be determined whether to add the HARQ-ACK bit of the cell with the next index (CC#1). If the number of bits in the semi-static HARQ-ACK codebook to which the HARQ-ACK bit has been added is greater than the number of bits that the terminal can transmit, the HARQ-ACK bit is not added to the semi-static HARQ-ACK codebook. In this way, it can be determined whether to add the HARQ-ACK bit of the cell with the last index.

[0385] When a terminal generates a semi-static HARQ-ACK codebook, multiple bits may correspond to one slot. Another method proposed in the present invention is a method for reducing the number of bits when multiple bits correspond to one slot. In the above first to fourth embodiments, a dropping method has been described in which the terminal transmits some of the HARQ-ACK bits and does not transmit the rest. Here, a bundling method will be described instead of the dropping method.

[0386] 30 is a diagram illustrating a method for reducing the HARQ-ACK size within one slot according to an embodiment of the present invention. In particular, FIG. 30 illustrates that three PDSCH candidates are configured in one slot.

[0387] - PDSCH candidate A occupies symbols 0 through 13;

[0388] - PDSCH candidate B occupies symbols 0 through 6;

[0389] - PDSCH candidate C occupies symbols 7 to 13.

[0390] A terminal can receive only one PDSCH per symbol, but PDSCH candidate A and PDSCH candidate B overlap at symbol 0 to symbol 6, so they cannot be scheduled for reception at the same time. Also, PDSCH candidate A and PDSCH candidate C overlap at symbol 7 to symbol 13, so they cannot be scheduled for reception at the same time. Therefore, the combinations that can be scheduled for reception by a terminal are only PDSCH candidate A, or one or two of PDSCH candidates B and C. This can be simply expressed as follows:

[0391] - {A}, {B}, {C}

[0392] - {B,C}

[0393] Referring to FIG. 30, the Type-1 HARQ-ACK codebook may be configured with a maximum of two PDSCH HARQ-ACK bits per slot by definition. For ease of explanation, it is assumed that the PDSCH HARQ-ACK is one bit. That is, the Type-1 HARQ-ACK codebook is configured with two bits for the HARQ-ACK information of a maximum of two PDSCHs per slot. Let this be [b0 b1]. Here,

[0394] b0 may transmit HARQ-ACK information for PDSCH candidate A or PDSCH candidate B.

[0395] b1 may transmit HARQ-ACK information for PDSCH candidate C.

[0396] Assume that the terminal receives PDSCH candidate A. This may include the case where a PDCCH scheduling PDSCH candidate A is received or an SPS PDSCH is configured for PDSCH candidate A. As described above, when PDSCH candidate A is scheduled, other PDSCH candidates cannot be scheduled. That is, PDSCH candidate C corresponding to b1 cannot be scheduled, and therefore b1 must always transmit a NACK. In other words, when PDSCH candidate A is scheduled, the type-1 HARQ-ACK codebook includes [b0 NACK]. Here, b0 may be mapped to the HARQ-ACK bit of the PDSCH received by PDSCH candidate A.

[0397] The terminal 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 1 bit. Here, bundling may be defined as follows:

[0398] - If HARQ-ACK for all bits (b0 and b1) is ACK, then ACK

[0399] - Otherwise (if at least one HARQ-ACK in all bits (b0 and b1) is NACK), NACK

[0400] In the above example, if PDSCH candidate A is received, it is assumed that [b0 b1] = [b0 NACK]. Therefore, when two bits (b0 and b1) are bundled, a NACK is always determined. This determination is made regardless of whether PDSCH candidate A is successfully received. Therefore, the type-1 HARQ-ACK codebook generated as a result of the bundling process cannot convey information about the successful reception of the PDSCH. The present invention discloses a method for solving this problem.

[0401] A method of bundling type-1 HARQ-ACK codebooks according to an embodiment of the present invention is as follows.

[0402] - For a bit position in type-1 HARQ-ACK code, if a PDSCH is received and all of the corresponding PDSCH candidates associated with the bit position overlaps with the received PDSCH, the bit position is considered as "X (3 rd state)" for bundling

[0403] o Rule A) 'X' is treated as "ACK" when bundling and the bundling of bits containing "X'" only is NACK.

[0404] o Rule B) 'X' is removed first, and the remaining state are bundled. After bundling, if the bit-size is less than the intended size then add NACKs

[0405] Referring to FIG. 30, bundling according to the above embodiment is as follows.

[0406] In [b0 b1], if the terminal receives scheduling information for PDSCH candidate A, the terminal knows that PDSCH candidate B and PDSCH candidate C cannot be scheduled. Therefore, the b0 bit is mapped to ACK / NACK indicating whether PDSCH candidate A was received successfully, and the b1 bit is mapped to "X(3 rdstate) may be mapped, i.e., it can be shown that [b0 b1] = [b0 X].

[0407] By Rule A, "X" is considered as an ACK when bundling. Therefore, when b0 and X are bundled with 1 bit, the bundled 1 bit is b0.

[0408] Rule B excludes "X". When it is excluded, it becomes [b0]. Therefore, when it is bundled with 1 bit, the bundled 1 bit becomes b0.

[0409] When the base station receives the bundled one bit, it can determine that the bundled one bit is the HARQ-ACK of PDSCH candidate A using information that the base station has already scheduled PDSCH candidate A.

[0410] 31 is a diagram illustrating a method for reducing the HARQ-ACK size within one slot according to an embodiment of the present invention. In particular, FIG. 31 illustrates that seven PDSCH candidates are configured in one slot.

[0411] - PDSCH candidate A occupies symbols 0 through 13;

[0412] - PDSCH candidate B occupies symbols 0 to 6;

[0413] - PDSCH candidate C occupies symbols 7 to 13.

[0414] - PDSCH candidate D occupies symbols 0 through 3;

[0415] - PDSCH candidate E occupies symbols 4 through 7;

[0416] - PDSCH candidate F occupies symbols 8 through 11;

[0417] PDSCH candidate G occupies symbols 12 to 13.

[0418] A 4-bit HARQ-ACK bit may be generated for the PDSCH candidate of this slot by the Type-1 HARQ-ACK codebook generation method, which is represented as [b0 b1 b2 b3], where:

[0419] b0 may transmit HARQ-ACK information for PDSCH candidate A, PDSCH candidate B, or PDSCH candidate D.

[0420] b1 may transmit HARQ-ACK information of PDSCH candidate C or PDSCH candidate E.

[0421] - b2 may transmit HARQ-ACK information for PDSCH candidate F.

[0422] - b3 may transmit HARQ-ACK information for PDSCH candidate G.

[0423] The combinations that can be simultaneously scheduled in one slot for terminals can be expressed as follows:

[0424] o {A}, {B}, {C}, {D}, {E}, {F}, {G}

[0425] o {B,C}, {B,F}, {B,G}, {C,D}, {D,E}, {D,F}, {D,G}, {E,F}, {E,G}, {F,G}

[0426] o {B,F,G}, {D,E,F}, {D,E,G}, {D,F,G}, {E,F,G}

[0427] {D,E,F,G}

[0428] To reduce the number of bits in the semi-static HARQ-ACK codebook, the terminal can bundle 4 bits into 2 bits or 1 bit. Table 7 shows 2-bit bundling and 1-bit bundling. Here, bundling is performed by performing a binary AND operation on adjacent ACK / NACKs (ACK=1, NACK=0). That is, in the case of 2-bit bundling, the first 2 bits of the 4 bits are subjected to a binary AND operation to obtain the first bit, and the last 2 bits are subjected to a binary AND operation to obtain the second bit. In the case of 1-bit bundling, 4 bits are subjected to a binary AND operation to obtain 1 bit.

[0429] 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 a NACK.

[0430] As can be seen in Table 7, in the case of 1-bit bundling, the terminal always transmits 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 terminal always transmits [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}, {D,E,F,G} are scheduled.

[0431] [Table 7]

[0432] Tables 8 and 9 show HARQ-ACK bundling according to one embodiment of the present invention. Table 8 uses Rule A, and Table 9 uses Rule B.

[0433] Referring to Tables 8 and 9, the terminal determines "X(3 rd This allows the determination of the HARQ-ACK including X(3 rd For example, when a terminal receives scheduling information corresponding to PDSCH candidate A, PDSCH candidates to which HARQ-ACK is mapped to b1, b2, and b3 cannot be scheduled. Therefore, b1, b2, and b3 are not X(3 rd state).

[0434] Referring to Table 8, based on Rule A, the terminal rd state) for bundling can be bundled with 2 bits or 1 bit. By Rule A, X(3 rd state) is considered an ACK when bundled with other ACK / NACKs. rd In Table 8, b023 is the result of performing a binary AND operation on b0, b2, and b3.

[0435] As can be seen from Table 8, in the case of 1-bit bundling, the terminal transmits a NACK except when PDSCH candidates {A}, {B,C}, {C,D}, {B,F,G}, and {D,E,F,G} are scheduled. Compared with Table 7, this indicates that meaningful ACK / NACK information can be transmitted when PDSCH candidates {A}, {B,C}, {C,D}, and {B,F,G} are scheduled. In the case of 2-bit bundling, the terminal transmits a 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, this shows that meaningful ACK / NACK information can be transmitted when PDSCH candidates {A}, {B,F}, and {B,F,G} are scheduled.

[0436] [Table 8]

[0437] Referring to Table 8, based on Rule B, the terminal sends the 4-bit HARQ-ACK including X(3 rd state) for bundling in "X(3 rd state)" and HARQ-ACK removing X(3 rd state) for bundling, and HARQ-ACK removing X(3 rd If the state) for bundling is greater than the number of bits after bundling, some bits can be bundled by performing a binary AND operation. HARQ-ACK removing X(3 rd If the state for bundling is smaller than the number of bits after bundling, then the NACK can be padded after it. For example, in the case of 2-bit bundling, the HARQ-ACK is removed by removing X(3 rd If the state) for bundling is 1 bit, pad the NACK after that 1 bit to make it 2 bits. In the case of 2-bit bundling, remove HARQ-ACK X(3 rd If the state) for bundling is 2 bits, then the 2 bits are the bundling result. In the case of 2-bit bundling, HARQ-ACK removing X(3 rd If the state) for bundling is 3 bits, perform a Binary AND operation on the first 2 bits to obtain 1 bit, and then remove HARQ-ACK from X(3 rd The two bits, including the last bit of the "state" for bundling, are the result of bundling. In Table 9, b023 is the result of performing a binary AND operation on b0, b2, and b3, and b02 is the result of performing a binary AND operation on b0 and b2.

[0438] As can be seen from Table 9, in the case of 1-bit bundling, the terminal transmits a NACK except when PDSCH candidates {A}, {B,C}, {C,D}, {B,F,G}, and {D,E,F,G} are scheduled. Compared with Table 7, this indicates that meaningful ACK / NACK information can be transmitted when PDSCH candidates {A}, {B,C}, {C,D}, and {B,F,G} are scheduled. In the case of 2-bit bundling, the terminal transmits a 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. This shows that meaningful ACK / NACK information can be transmitted when PDSCH candidates {A}, {B,F}, and {B,F,G} are scheduled, as compared with Table 7. This shows that meaningful ACK / NACK information can be transmitted when PDSCH candidate {C} is scheduled, as compared with Table 8.

[0439] [Table 9]

[0440] In the case of 1-bit bundling, the following operation can be considered: In the case of 1-bit bundling, if the UE receives scheduling information of one PDSCH in a slot, it can use the success or failure of receiving the PDSCH as the result value of 1-bit bundling.

[0441] Referring to Table 10, when PDSCH candidates {A}, {B}, {C}, {D}, {E}, {F}, and {G} are scheduled, the UE can use the HARQ-ACK of the PDSCH as the result of 1-bit bundling since one PDSCH is scheduled in the slot. When two or more PDSCH candidates are scheduled, the UE can use NACK as the result of 1-bit bundling. As another example, when two or more PDSCH candidates are scheduled, the UE can determine 1-bit bundling using the method of Table 8 or Table 9.

[0442] [Table 10]

[0443] Assume that the number of bits in the HARQ-ACK codebook of a terminal is given as A bits. Also, assume that the number of bits that the terminal can transmit is given as B bits. The terminal can bundle A bits to make it B bits or less than B bits. Here, a specific bundling method will be described.

[0444] As a first method, the terminal bundles 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. The bits included in each bundle are binary ANDed to generate one bit per bundle.

[0445] For example, assume that the HARQ-ACK codebook is A = 10 bits (hereinafter, [b0 b1 b2 b3 b4 b5 b6 b7 b8 b9]) and the number of bits that the terminal can transmit is given as B = 3 bits. According to the first method, the terminal bundles ceil(10 / 3) = 4 bits from the first 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, the first bit after bundling is the value obtained by performing a binary AND operation on [b0 b1 b2 b3], the second bit is the value obtained by performing a binary AND operation on [b4 b5 b6 b7], and the third bit is the value obtained by performing a binary AND operation on [b8 b9].

[0446] As another example of the first method, the terminal aggregates every X bits from the first bit of the HARQ-ACK codebook, where X is a power of 2 and is greater than or equal to ceil(A / B).

[0447] In the second method, the terminal aggregates the HARQ-ACK codebook into bundles of ceil(A / B) bits and bundles of floor(A / B) bits. The number of bundles of ceil(A / B) bits is A mod B, and the number of bundles of floor(A / B) bits is B-(A mod B). The bits included in each bundle are binary ANDed to generate one bit per bundle.

[0448] For example, assume that the HARQ-ACK codebook is A = 10 bits (hereinafter, [b0 b1 b2 b3 b4 b5 b6 b7 b8 b9]) and the number of bits that the terminal can transmit is given as B = 3 bits. Using the second method, the terminal can configure one bundle of ceil(10 / 3) = 4 bits of the HARQ-ACK codebook and two bundles of 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, the first bit after bundling is the value obtained by performing a binary AND operation on [b0 b1 b2 b3], the second bit is the value obtained by performing a binary AND operation on [b4 b5 b6], and the third bit is the value obtained by performing a binary AND operation on [b7 b8 b9].

[0449] In the third method, the terminal separates the HARQ-ACK codebook into B-1 bit and A-(B-1) bit, performs a binary AND operation on the A-(B-1) bit to generate 1 bit, and then combines the B-1 bit and the previously generated 1 bit from the HARQ-ACK codebook to generate B bit.

[0450] For example, assume that the HARQ-ACK codebook is A=10 bits (hereinafter, [b0 b1 b2 b3 b4 b5 b6 b7 b8 b9]) and the number of bits that the terminal can transmit is given as B=3 bits. Using the third method, the terminal 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 terminal can generate 1 bit by performing a binary AND operation on the 8 bits and combine the 1 bit with [b0 b1] to generate B=3 bits.

[0451] For reference, if A is a multiple of ceil(A / B), then all lattices have ceil(A / B) bits, but if A is not a multiple of ceil(A / B), then the final lattice has A mod ceil(A / B) bits. The bits in each lattice are binary ANDed to produce one bit per lattice.

[0452] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not restrictive. For example, each component described as a single component may be implemented in a distributed form, and similarly, each component described as a distributed component may be implemented in a combined form.

[0453] The scope of the present invention is indicated by the claims set forth below rather than by the above detailed description, and all modifications and variations that fall within the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention. [Explanation of symbols]

[0454] 100 devices 110 processors 120 Communication Module 121,122 Cellular communication interface card 123 Unlicensed Spectrum Communication Interface Card 130 memory 140 User Interface Section 150 display units 200 base stations 210 processors 220 Communication Module 221,222 Cellular communication interface card 223 Unlicensed Spectrum Communication Interface Card 230 memory

Claims

1. 1. A terminal configured to operate in a wireless communication system, comprising: a processor; Communication module and Equipped with The processor: receiving downlink control information (DCI) for downlink scheduling, the DCI including a subslot offset k, where k is a set K: {k ０ , k １ , ..., k ｍ－１ }, and To generate a semi-static hybrid automatic repeat request (HARQ)-ACK codebook, k ｉ , and each element k of the set K when ｉ Regarding Uplink (UL) sub-slot #(n ｕ -k ｉ The first downlink (DL) slot that overlaps with UL subslot #(n ｕ -k ｉ－１ ), if there is no overlap with the first DL slot, including HARQ-ACK information for the first DL slot in the semi-static HARQ-ACK codebook; and The first DL slot is a UL sub-slot #(n ｕ -k ｉ－１ ), skip including the HARQ-ACK information for the first DL slot in the semi-static HARQ-ACK codebook. and UL subslot #n ｕ transmitting the semi-static HARQ-ACK codebook via a physical uplink control channel (PUCCH) in configured to: A terminal, wherein a DL slot includes 14 symbols and a UL sub-slot includes X symbols, where X is a number less than 14.

2. The generation of the HARQ-ACK information includes: The end of the corresponding PDSCH (physical downlink shared channel) candidate in the first DL slot is any UL sub-slot # (n ｕ -k ｐ determining a set of valid PDSCH candidates for the first DL slot based on whether the PDSCH candidates are within k ｐ The terminal of claim 1 , wherein k is at least a portion of the set K.

3. k ｐ 2. The terminal of claim 1, wherein r has multiple values ​​corresponding to UL subslots that overlap with the first DL slot.

4. 2. The terminal of claim 1, wherein, if the terminal does not have the capability to receive two or more PDSCHs in one DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information only for reception of one PDSCH when at least one valid PDSCH candidate is present in the first DL slot.

5. 10. The terminal of claim 1, wherein, when the terminal has the capability to receive two or more PDSCHs in one DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information for reception of one or more PDSCHs based on the set of valid PDSCH candidates.

6. 6. The terminal of claim 5, wherein, when the terminal has the capability to receive two or more PDSCHs in one DL slot, the same HARQ-ACK bit position is assigned to both (i) a first valid PDSCH candidate having a last symbol index that is the smallest value and (ii) zero or more second valid PDSCH candidates that overlap in the time domain with the first valid PDSCH candidate, and then the first valid PDSCH candidate and the zero or more second valid PDSCH candidates are removed from the set of valid PDSCH candidates.

7. Multiple DL slots are UL sub-slots #(n ｕ -k ｉ 2. The terminal of claim 1, wherein, if the first DL slot is within a range of 0 to 100, the first DL slot corresponds to each of the plurality of DL slots in ascending order starting from a DL slot having a smallest index among the plurality of DL slots.

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

9. The terminal of claim 1 , wherein the DCI is received via a physical downlink control channel (PDCCH).

10. 1. A method performed by a terminal configured to operate in a wireless communication system, comprising: receiving downlink control information (DCI) for downlink scheduling, the DCI including a subslot offset k, where k is a set K: {k ０ , k １ , ..., k ｍ－１ }, and To generate a semi-static hybrid automatic repeat request (HARQ)-ACK codebook, k ｉ , and each element k of the set K when ｉ Regarding Uplink (UL) sub-slot #(n ｕ -k ｉ The first downlink (DL) slot that overlaps with UL subslot #(n ｕ -k ｉ－１ ), if there is no overlap with the first DL slot, including HARQ-ACK information for the first DL slot in the semi-static HARQ-ACK codebook; and The first DL slot is a UL sub-slot #(n ｕ -k ｉ－１ ), skip including the HARQ-ACK information for the first DL slot in the semi-static HARQ-ACK codebook. and UL subslot #n ｕ transmitting the semi-static HARQ-ACK codebook via a physical uplink control channel (PUCCH) in Including, A method wherein a DL slot includes 14 symbols and a UL sub-slot includes X symbols, where X is a number less than 14.

11. The generation of the HARQ-ACK information includes: The end of the corresponding PDSCH (physical downlink shared channel) candidate in the first DL slot is any UL sub-slot # (n ｕ -k ｐ determining a set of valid PDSCH candidates for the first DL slot based on whether the PDSCH candidates are within k ｐ The method of claim 10 , wherein k is at least a portion of the set K.

12. k ｐ The method of claim 10 , wherein Λ has multiple values ​​corresponding to UL sub-slots that overlap with the first DL slot.

13. 11. The method of claim 10, wherein, if the terminal does not have the capability to receive two or more PDSCHs in one DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information only for reception of one PDSCH when at least one valid PDSCH candidate is present in the first DL slot.

14. 11. The method of claim 10, wherein if the terminal has the capability to receive two or more PDSCHs in one DL slot, the HARQ-ACK information for the first DL slot includes HARQ-ACK information for reception of one or more PDSCHs based on the set of valid PDSCH candidates.

15. 15. The method of claim 14, wherein, if the terminal has the capability to receive two or more PDSCHs in one DL slot, the same HARQ-ACK bit position is assigned to both (i) a first valid PDSCH candidate having a last symbol index that is the smallest value and (ii) zero or more second valid PDSCH candidates that overlap with the first valid PDSCH candidate in the time domain, 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.

16. Multiple DL slots are UL sub-slots #(n ｕ -k ｉ 11. The method of claim 10, wherein if the first DL slot is within a range of 0 to 10, the first DL slot corresponds to each of the plurality of DL slots in ascending order, starting from the DL slot having the smallest index among the plurality of DL slots.

17. The method of claim 10, wherein the end of the corresponding PDSCH candidate is determined based on a start and length indicator value (SLIV) of the first DL slot.

18. The method of claim 10 , wherein the DCI is received via a physical downlink control channel (PDCCH).

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