Device and method for transmitting uplink control channel in wireless communication system

Abstract

To provide a method for HARQ-ACK transmission that can secure a lower latency time.SOLUTION: A method that a termina transmits a physical uplink control channel (PUCCH) to a base station in a wireless communication system includes the steps of: a first HARQ-ACK codebook related to a first PUCCH; generating a second HARQ-ACK codebook related to a second PUCCH; and transmitting simultaneously the first PUCCH and the second PUCCH or one PUCCH among the first PUCCH and the second PUCCH to a base station in one slot on the basis of a plurality of indicators. The first PUCCH and the second PUCCH correspond to a first indicator and a second indicator, which have different values, respectively, and the one PUCCH is determined to be the first PUCCH or the second PUCCH on the basis of the first and second indicators.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to wireless communications, and more particularly to an apparatus and method for transmitting an uplink control channel in a wireless communications system, an apparatus and method for receiving an uplink control channel, and a downlink control device and method therefor. [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 (registered trademark, hereinafter the same) (3rd generation partnership project) NR system improves network spectrum efficiency, allowing 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] 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).

[0005] 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.

[0006] 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.

[0007] Future 5G technology requires lower latency data transmission with the emergence of new applications such as real-time control and tactile internet, and the required latency for 5G data is expected to be as low as 1 ms. 5G aims to provide data latency that is approximately 10 times lower than conventional standards. To solve this problem, 5G is expected to propose a communication system that uses minislots with a shorter TTI period (e.g., 0.2 ms) in addition to the existing slots (or subframes).

[0008] Various technologies are being discussed to provide lower latency and higher reliability for the enhanced ultra reliable low latency communication (URLLC) currently under development in 3GPP Release 16. Among these, transmission of an uplink control channel (ULCCH) containing two or more HARQ-ACKs per slot is supported to provide lower latency. This allows a terminal to transmit a HARQ-ACK as soon as possible in response to the success or failure of downlink shared channel reception, thereby ensuring lower latency. In particular, when multiple PUCCHs for transmitting multiple HARQ-ACKs exist in one slot, new definitions are needed for the PUCCH transmission procedure and HARQ-ACK timing. Summary of the Invention [Problem to be solved by the invention]

[0009] A technical object of the present invention is to provide an apparatus and method for transmitting an uplink control channel, an apparatus and method for receiving an uplink control channel, and an apparatus and method for controlling a downlink channel therefor in a wireless communication system.

[0010] Another technical object of the present invention is to provide a method for transmitting downlink control information for multiple PUCCH transmissions and a method for determining HARQ-ACK information included in the PUCCH.

[0011] Yet another technical object of the present invention is to provide an apparatus and method for resolving collisions among multiple PUCCHs by indicating multiple PUCCHs for which individual HARQ-ACKs are transmitted.

[0012] Yet another technical object of the present invention is to provide a method for a base station to transmit a PDSCH group indicator to a terminal, the PUCCH group indicator indicating multiple PUCCHs on which individual HARQ-ACKs are transmitted.

[0013] A further technical object of the present invention is to provide a method for defining k1, which indicates the HARQ-ACK timing, as a unit smaller than a slot.

[0014] Another technical object of the present invention is to provide a method for a base station to transmit a HARQ-ACK multiplexing indicator to a terminal, the HARQ-ACK multiplexing indicator indicating whether or not to perform HARQ-ACK multiplexing. [Means for solving the problem]

[0015] According to one aspect of the present invention, there is provided a method for a terminal in a wireless communication system to transmit a physical uplink control channel (PUCCH) to a base station, the method including: generating a first HARQ-ACK codebook associated with a first PUCCH; generating a second HARQ-ACK codebook associated with a second PUCCH; and simultaneously transmitting the first PUCCH and the second PUCCH to the base station in one slot, or transmitting either the first PUCCH or the second PUCCH to the base station in one slot.

[0016] Here, the first PUCCH and the second PUCCH correspond to a first indicator and a second indicator, respectively, having different values, and the one PUCCH may be determined from the first PUCCH or the second PUCCH based on the first indicator and the second indicator.

[0017] In one aspect, when the first PUCCH corresponds to the first indicator having a value of 0, the second PUCCH corresponds to the second indicator having a value of 1, and when the first PUCCH corresponds to the first indicator having a value of 1, the second PUCCH corresponds to the second indicator having a value of 0.

[0018] In another aspect, the method may further include receiving the first indicator corresponding to the first PUCCH and the second indicator corresponding to the second PUCCH from the base station via a physical downlink control channel or RRC (radio resource control) signaling.

[0019] In yet another aspect, the first HARQ-ACK codebook may be generated in a semi-static manner, and the second HARQ-ACK codebook may be generated in a dynamic manner.

[0020] In yet another aspect, the step of simultaneously transmitting the first PUCCH and the second PUCCH to the base station in one slot may be performed when the transmission of the first PUCCH and the second PUCCH does not collide, and the step of transmitting any one of the first PUCCH and the second PUCCH may be performed when the transmission of the first PUCCH and the second PUCCH collide, and when the transmission of the first PUCCH and the second PUCCH collide, the step may include a case where the resources for the first PUCCH and the resources for the second PUCCH at least partially overlap.

[0021] In yet another aspect, the step of transmitting one of the first PUCCH and the second PUCCH may further include the step of multiplexing the first HARQ-ACK codebook and the second HARQ-ACK codebook and mapping them to the one PUCCH.

[0022] In yet another aspect, the method further includes receiving at least one physical downlink shared channel (PDSCH) associated with the first PUCCH or the second PUCCH in a slot preceding the one slot, and an interval between the reception timing of the PDSCH and the transmission timing of a PUCCH including a HARQ-ACK codebook for the at least one PDSCH may be defined as a number (= b) of symbol units that is less than the number (= a) of symbols constituting the one slot or the preceding slot.

[0023] In yet another aspect, b may be half of a.

[0024] In yet another aspect, the one slot and the preceding slot each include multiple subslots, and the HARQ-ACK codebook for the at least one PDSCH may include a number of HARQ-ACKs equal to the maximum number of PDSCHs receivable in the preceding slot.

[0025] In yet another aspect, the method further includes receiving a semi-statically scheduled PDSCH in a slot preceding the one slot, and if a HARQ-ACK for the semi-statically scheduled PDSCH cannot be transmitted after k1 slots from the preceding slot, a transmission timing of the HARQ-ACK for the semi-statically scheduled PDSCH may be delayed to the one slot, where k1 may be an interval between a reception timing of the semi-statically scheduled PDSCH and a transmission timing of a PUCCH including a HARQ-ACK for the PDSCH.

[0026] In yet another aspect, the method may further include a step in which a transmission period of the semi-statically scheduled PDSCH is set by the base station, and an interval between the k1 slots after the preceding slot and the one slot may be determined to be a multiple of the transmission period.

[0027] According to another aspect of the present invention, there is provided a method for a base station in a wireless communication system to receive a physical uplink control channel (PUCCH) from a terminal, the method including the steps of: transmitting a first physical downlink shared channel (PDSCH) and a second PDSCH to the terminal in a first slot; and simultaneously receiving a first PUCCH including a first HARQ-ACK codebook for the first PDSCH and a second PUCCH including a second HARQ-ACK codebook for the second PDSCH from the terminal in a second slot, or receiving one of the first PUCCH and the second PUCCH from the terminal.

[0028] Here, the first PUCCH and the second PUCCH correspond to a first indicator and a second indicator, respectively, having different values, and the one PUCCH may be determined from the first PUCCH or the second PUCCH based on the first indicator and the second indicator.

[0029] In one aspect, when the first PUCCH corresponds to the first indicator having a value of 0, the second PUCCH may correspond to the second indicator having a value of 1, and when the first PUCCH corresponds to the first indicator having a value of 1, the second PUCCH may correspond to the second indicator having a value of 0.

[0030] In another aspect, the method may further include transmitting the first indicator corresponding to the first PUCCH and the second indicator corresponding to the second PUCCH to the terminal via a physical downlink control channel (PDCCH) or RRC (radio resource control) signaling.

[0031] In yet another aspect, the first HARQ-ACK codebook may be generated in a semi-static manner, and the second HARQ-ACK codebook may be generated in a dynamic manner.

[0032] In yet another aspect, the step of simultaneously receiving the first PUCCH and the second PUCCH from the terminal in the second slot may be performed when the transmission of the first PUCCH and the second PUCCH does not collide, and the step of receiving one of the first PUCCH and the second PUCCH may be performed when the transmission of the first PUCCH and the second PUCCH collide, and when the transmission of the first PUCCH and the second PUCCH collide, the step may include a case where the resources for the first PUCCH and the resources for the second PUCCH at least partially overlap.

[0033] In yet another aspect, the step of receiving one of the first PUCCH and the second PUCCH may further include the step of demultiplexing the one PUCCH to obtain the first HARQ-ACK codebook and the second HARQ-ACK codebook.

[0034] In yet another aspect, the interval between the transmission timing of the first and second PDSCHs and the reception timing of the first and second PUCCHs may be defined as a number (= b) of symbol units that is less than the number (= a) of symbols that constitute the first slot or the second slot.

[0035] In yet another aspect, each of the first slots may include a plurality of subslots, and the HARQ-ACK codebook for the first PDSCH may include a number of HARQ-ACKs equal to the maximum number of PDSCHs that can be received in the first slot.

[0036] In yet another aspect, the first PDSCH is a semi-persistently scheduled PDSCH, a transmission period for the first PDSCH is set by the base station, the interval between the first slot and the second slot is k1, and if the first PUCCH cannot be transmitted in the second slot, the transmission timing of the first PUCCH is delayed to a third slot, and k1 may be the interval between the reception timing of the first PDSCH and the transmission timing of the first PUCCH. [Effects of the Invention]

[0037] According to this embodiment, the transmission procedure for multiple PUCCHs each containing a different HARQ-ACK in one slot is clarified, thereby achieving the target performance of a 5G wireless communication system that attempts to simultaneously provide various types of traffic (eURLLC, eMBB).

[0038] The effects obtained from the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief explanation of the drawings]

[0039] [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 5] 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] 10 is a flowchart illustrating a method for transmitting multiple PUCCHs in one slot using an indicator according to an embodiment. [Figure 13] FIG. 10 is a diagram illustrating an example of a method for transmitting multiple PUCCHs in one slot. [Figure 14] FIG. 10 is a diagram illustrating another example of a method for transmitting multiple PUCCHs in one slot. [Figure 15] FIG. 10 is a diagram illustrating a method for defining the unit of the k1 value as a sub-slot, which is a unit smaller than a basic slot. [Figure 16] FIG. 1 illustrates a situation where multiple PUCCH transmissions collide within one slot according to an example. [Figure 17] 1 illustrates multiple PDSCH candidates that can be transmitted across a sub-slot according to an example. [Figure 18] FIG. 10 is a diagram illustrating an example of a process for generating a semi-static HARQ-ACK codebook based on half slots. [Figure 19]FIG. 10 is a diagram illustrating a process for generating a semi-static HARQ-ACK codebook based on half slots according to another example. [Figure 20] FIG. 20 is a diagram illustrating the result of semi-static HARQ-ACK codebook generation according to FIG. 19. [Figure 21] A diagram showing PUCCH transmission of a terminal using a HARQ-ACK multiplexing indicator according to an example. [Figure 22] A diagram showing PUCCH transmission by a terminal using a HARQ-ACK multiplexing indicator according to another example. [Figure 23] 10 is a diagram illustrating a method for determining a PUCCH resource when the k1 and PRI fields are not configured (or indicated) in a terminal according to an example. FIG. [Figure 24] 10 is a diagram illustrating a method in which a terminal transmits HARQ-ACK bits for multiple SPS PDSCHs in one slot according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0040] 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 analyzed based on the substantive meaning of the terms and the overall content of this specification, rather than simply the names of the terms.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] FIG. 1 is a diagram illustrating an example of a radio frame structure used in a radio communication system.

[0045] 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).

[0046] 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.

[0047] 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.

[0048] 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).

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] If the information regarding the symbol type consists of the UE-specific RRC signal, the base station signals whether the flexible symbol is a downlink symbol or an uplink symbol by using the cell-specific RRC signal. At this time, the UE-specific RRC signal cannot change the downlink symbol or uplink symbol that consists of the cell-specific RRC signal to another symbol type. The specific UE RRC signal signals 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 for each slot. At this time, the downlink symbols of the slot are continuously configured from the first symbol to the i-th symbol of the slot. Also, the uplink symbols of the 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.

[0054] FIG. 3 is a diagram for explaining a physical channel used in a 3GPP system (e.g., NR) and a general signal transmission method using the corresponding physical channel.

[0055] If the terminal is powered on or newly enters a cell, the terminal performs an initial cell search operation S101. Specifically, the terminal synchronizes with the base station in the initial cell search. For this purpose, the terminal receives the primary synchronization signal (PSS) and the secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtains information such as the cell ID. Next, the terminal receives the physical broadcast channel from the base station and obtains the broadcast information in the cell.

[0056] 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 to acquire 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.

[0057] 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).

[0058] 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.

[0059] 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.

[0060] FIG. 4 is a diagram illustrating an SS / PBCH block for initial cell access in a 3GPP NR system.

[0061] 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 cell's physical cell identity (NcellID). To do this, 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).

[0062] The synchronization signal (SS) will be described in more detail with reference to FIG. 4(a). 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 FIG. 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 through subcarriers 48 to 55 and 183 to 191. The base station transmits a physical broadcast channel (PBCH) through the remaining REs in the SS / PBCH block excluding the above signals.

[0063] [Table 1]

[0064] 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 a 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 expressed as Equation 1 below.

[0065] d PSS (n)=1-2x(m)

[0066] m=(n+43N (2 ) ID ) mod 127

[0067] 0≦n<127

[0068] where x(i+7)=(x(i+4)+x(i)) mod 2,

[0069] Given that [x(6)x(5)x(4)x(3)x(2)x(1)x(0)]=[1110110].

[0070] Also, the sequence of SSS SSS (n) is as follows:

[0071] d SSS(n)=[1-2x0((n+m0) mod 127][1-2x i ((n+m1) mod 127]

[0072] m0=15 floor(N( 1 ) ID / 112)+5N( 2 ) ID

[0073] m1=N( 1 ) ID mod 112

[0074] 0≦n<127

[0075] where x0(i+7)=(x0(i+4)+x0(i))mod 2

[0076] x1(i+7)=(x1(i+1)+x1(i))mod 2,

[0077] [x0(6)x0(5)x0(4)x0(3)x0(2)x0(1)x0(0)]=[0000001]

[0078] Given that [x1(6)x1(5)x1(4)x1(3)x1(2)x1(1)x1(0)]=[0000001].

[0079] 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 {2, 8}+14*n symbols, 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 {4, 8, 16, 20}+28*n symbols, 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 {8, 12, 16, 20, 32, 36, 40, 44}+56*n symbols. In this case, n=0, 1, 2, 3, 5, 6, 7, 8 for carrier frequencies above 6 GHz.

[0080] 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. The base station then performs channel encoding (e.g., polar coding) S204 and rate-matching S206 according to the amount of resource(s) used for PDCCH transmission. The base station then 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.

[0081] FIG. 6 is a diagram showing a CORESET in which a PDCCH is transmitted in a 3GPP NR system.

[0082] A CORESET is a time-frequency resource in 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.

[0083] FIG. 7 is a diagram illustrating a method for configuring a PDCCH search space in a 3GPP NR system.

[0084] 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 UEs monitor the PDCCHs allocated to each UE at different search space positions. 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, the PDCCH is said to be (successfully) detected / received, and if blind decoding fails, the PDCCH is said to be undetected / unreceived or not successfully detected / received.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] Table 2 shows an example of a PUCCH used in a wireless communication system.

[0089] [Table 2]

[0090] The PUCCH is used to transmit the following uplink control information (UCI):

[0091] - SR (Scheduling Request): Information used to request uplink UL-SCH resources.

[0092] 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.

[0093] 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.

[0094] In the 3GPP NR system, five PUCCH formats are used to support various service scenarios, various channel environments, and frame structures.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] FIG. 8 is a conceptual diagram illustrating carrier aggregation.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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).

[0112] 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.

[0113] 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.

[0114] 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.

[0115] In the embodiment of Figure 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 that schedules 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) uses the CIF to transmit not only a PDCCH that schedules the PDSCH of DL CC A but also a PDCCH that schedules the PDSCH of another CC (cross-carrier scheduling). On the other hand, no PDCCH is transmitted on other DL CCs. Therefore, depending on whether cross-carrier scheduling is configured for the UE, the UE monitors a PDCCH that does not include a CIF to receive a self-carrier scheduled PDSCH, or monitors a PDCCH that includes a CIF to receive a cross-carrier scheduled PDSCH.

[0116] 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.

[0117] 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.

[0118] 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 .

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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 that the corresponding NIC module supports.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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 .

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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, 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.

[0133] 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.

[0134] To support services that require low latency and high reliability, such as URLLC services, a terminal must transmit HARQ-ACK as quickly as possible to receive fast retransmissions from a base station. However, 3GPP NR Release 15 only allows transmission of a maximum of one PUCCH containing HARQ-ACK information per slot. For this reason, a terminal may either i) transmit HARQ-ACK responses for different PDSCHs in different slots, or ii) multiplex them in one PUCCH. However, i) is not suitable for providing low latency, and ii) may cause problems with PUCCH coverage, i.e., reliability. Therefore, a method for transmitting multiple PUCCHs containing different HARQ-ACK information in one slot has been discussed.

[0135] Method for transmitting multiple PUCCHs in one slot based on indicators

[0136] 12 is a flowchart illustrating a method for transmitting multiple PUCCHs in one slot using an indicator according to an embodiment. The base station in FIG. 12 is the same as base station 200 in FIG. 11, and the terminal in FIG. 12 is the same as terminal 100 in FIG. 11.

[0137] Referring to FIG. 12, a base station transmits an indicator to a terminal (S1200). The indicator can indicate a value corresponding to the number of PUCCHs to be simultaneously transmitted within one slot. For example, if a maximum of two PUCCHs can be simultaneously transmitted within one slot, the indicator can have two values, for example, 0 or 1. That is, PUCCHs to be simultaneously transmitted within one slot are identified by each indicator. When an indicator value of 0 is assigned to one PUCCH, an indicator value of 1 is assigned to the other PUCCH. Similarly, when an indicator value of 1 is assigned to one PUCCH, an indicator value of 0 is assigned to the other PUCCH. The same indicator value cannot be assigned to different PUCCHs.

[0138] For example, referring to FIG. 13 , a terminal receives at least one PDSCH corresponding to an indicator value of 0 in a previous slot 1300, and then transmits a corresponding HARQ-ACK to the base station in a subsequent slot 1310 on a PUCCH 1320 corresponding to an indicator value of 0. Also, a terminal receives a PDSCH corresponding to an indicator value of 1 in a previous slot 1300, and then transmits a corresponding HARQ-ACK to the base station in a PUCCH 1330 corresponding to an indicator value of 1 in a subsequent slot 1310. That is, multiple PUCCHs 1320, 1330 simultaneously transmitted in a subsequent slot 1310 are indexed as 0 or 1 by the indicators. For example, if a first PUCCH corresponds to an indicator value of 0, a second PUCCH corresponds to an indicator value of 1, and if the first PUCCH corresponds to an indicator value of 1, the second PUCCH may correspond to an indicator value of 0. Such an indicator can be used as a criterion for collision resolution when multiple PUCCH transmissions collide within one slot.

[0139] The range of values ​​that the indicator can have can be generalized as follows: If the number of bits of the indicator is B, and X PUCCHs are transmitted in one slot, then B = ceil(log2(X)). In this case, the indicator can indicate one of the values ​​0, 1, . . . , X-1.

[0140] Such an indicator may be explicitly indicated or implicitly inferred from other information. If the indicator is implicitly inferred, step S1200 in FIG. 12 may be omitted. That is, the indicator is not separately signaled, and the terminal may implicitly derive the indicator from other information. In this case, this embodiment is an embodiment including the remaining steps with step S1200 omitted.

[0141] For example, the indicator may be included in a PDCCH (or DCI) that schedules the first PDSCH or the second PDSCH in step S1205 and transmitted. In this case, the indicator may be referred to as a PDSCH group indicator or a PDSCH group ID. However, for the sake of consistency in terminology, the indicator will be referred to as an "indicator" in this specification.

[0142] As another example, the indicator may be transmitted in RRC signaling.

[0143] As another example, the indicator may be information implicitly inferred from the value of another field of the PDCCH (or DCI) scheduling the first or second PDSCH or the value of another field of the RRC signaling. The method of implicitly inferring the indicator is similar to the method of implicitly determining the value of the HARQ-ACK multiplexing indicator described below.

[0144] The operation of the base station transmitting the indicator in step S1200 corresponds to the operation of the communication module 220 in FIG. 11, and the operation of the terminal receiving the indicator corresponds to the operation of the communication module 120 in FIG.

[0145] 12, the base station transmits a first PDSCH and a second PDSCH to the terminal (S1205). Here, the first PDSCH and the second PDSCH may be different types of traffic, for example, eMBB and URLLC. That is, the first PDSCH may be traffic related to eMBB, and the second PDSCH may be traffic related to URLLC. Although step S1205 in this embodiment transmits multiple PDSCHs, the base station may transmit only one PDSCH to the terminal. This is because the multiple PUCCHs transmitted in the subsequent slot 1310 may not necessarily include HARQ-ACKs related to the PDSCHs in the previous slot 1300, but may include other UCI, such as a scheduling request (SR), transmitted by the terminal regardless of the PDSCHs. The operation of the base station transmitting the first and second PDSCHs in step S1205 corresponds to the operation of the communication module 220 in FIG. 11, and the operation of the terminal receiving the first and second PDSCHs corresponds to the operation of the communication module 120 in FIG. 11.

[0146] The terminal generates a first HARQ-ACK codebook for the first PDSCH and a second HARQ-ACK codebook for the second PDSCH (S1210). The first HARQ-ACK codebook and the second HARQ-ACK codebook may be mapped to different PUCCHs within the same slot. In other words, the first HARQ-ACK codebook and the second HARQ-ACK codebook may be configured to be transmitted on different PUCCHs within the same slot. Here, the first HARQ-ACK codebook is mapped to the first PUCCH, and the second HARQ-ACK codebook is mapped to the second PUCCH.

[0147] When multiple PDSCHs are transmitted, the terminal multiplexes HARQ-ACKs of PDSCHs having the same indicator value to generate a HARQ-ACK codebook, and then transmits the HARQ-ACK codebook on the same PUCCH, as shown in FIG. 13. That is, when different indicator values ​​are used, different PUCCHs can be transmitted in one slot. Referring to FIG. 13, the terminal receives two PDSCHs corresponding to indicator value 1 in the previous slot 1300, multiplexes multiple HARQ-ACKs related to these PDSCHs to generate a HARQ-ACK codebook, and transmits the corresponding HARQ-ACK codebook on the PUCCH corresponding to indicator value 1 in the subsequent slot 1310. Also, the terminal receives two PDSCHs corresponding to indicator value 0 in the previous slot 1300, multiplexes multiple HARQ-ACKs related to these PDSCHs to generate a HARQ-ACK codebook, and transmits the corresponding HARQ-ACK codebook on the PUCCH corresponding to indicator value 0 in the subsequent slot 1310. As a result, a total of two PUCCHs are transmitted in one slot for four PDSCHs.

[0148] When multiple PUCCHs are transmitted, the method of generating a HARQ-ACK codebook for each PUCCH is as follows.

[0149] Each HARQ-ACK codebook may be generated in a different manner, for example, the first HARQ-ACK codebook may be generated in a semi-static manner, and the second HARQ-ACK codebook may be generated in a dynamic manner.

[0150] Meanwhile, the terminal must determine the HARQ-ACK bits included in each PUCCH, i.e., the HARQ-ACK codebook. In particular, if the terminal is configured to use a semi-static HARQ-ACK codebook (or a type 1 HARQ-ACK codebook), the terminal generates a semi-static HARQ-ACK codebook to be transmitted in the PUCCH corresponding to each indicator value. If the semi-static HARQ-ACK codebooks corresponding to each indicator value are independently generated without any separate definition, semi-static HARQ-ACK codebooks of the same size are transmitted in the same slot for each PUCCH, which may result in limited uplink PUCCH coverage.

[0151] Therefore, this embodiment provides a method for reducing the size of the semi-static HARQ-ACK codebook transmitted on the PUCCH corresponding to different indicator values ​​in one slot.

[0152] According to one aspect, the terminal includes PDSCH candidates that may be transmitted in a preceding half slot of two equally divided slots in a semi-static HARQ-ACK codebook corresponding to an indicator value of 0. The terminal may also include PDSCH candidates that may be transmitted in a following half slot in a semi-static HARQ-ACK codebook corresponding to an indicator value of 1. That is, the terminal and the base station can determine which indicator value the PDSCH candidate is included in using time domain resource assignment information occupied by the PDSCH candidate.

[0153] According to another aspect, a UE may determine which semi-static HARQ-ACK codebook the HARQ-ACK for the PDSCH corresponds to, based on a k1 value (PDSCH-to-HARQ_feedback timing indicator) indicated in the PDCCH (or DCI). Here, the k1 value is indicated in the PDSCH-to-HARQ_feedback timing indicator field of the PDCCH (or DCI) and is the interval (= number of slots) between the slot where the scheduled PDSCH ends and the slot where the PUCCH for the HARQ-ACK is transmitted. For example, when eight k1 values ​​are configured or assigned to a UE, the HARQ-ACK for the PDSCH indicated by the four smallest k1 values ​​among the eight k1 values ​​may be included in the semi-static HARQ-ACK codebook corresponding to an indicator value of 0, and the HARQ-ACK for the PDSCH indicated by the four largest k1 values ​​may be included in the semi-static HARQ-ACK codebook corresponding to an indicator value of 1.

[0154] According to yet another aspect, the UE can determine which semi-static HARQ-ACK codebook corresponding to which indicator value the HARQ-ACK of the PDSCH should be included in, depending on the value of the PDSCH length (number of symbols occupied) indicated in the PDCCH (or DCI). For example, if the (symbol) length of the PDSCH is 2 or 4, the HARQ-ACK for the PDSCH can be included in the semi-static HARQ-ACK codebook corresponding to indicator value 0, and the HARQ-ACK for the PDSCH whose (symbol) length is 7 or more can be included in the semi-static HARQ-ACK codebook corresponding to indicator value 1.

[0155] According to yet another aspect, a terminal may determine which semi-static HARQ-ACK codebook to include the HARQ-ACK of the PDSCH in, according to a PDSCH mapping type indicated by a PDCCH (or DCI). For example, if the PDSCH mapping type indicates A, the HARQ-ACK of the PDSCH may be included in the semi-static HARQ-ACK codebook corresponding to an indicator value of 0. If the PDSCH mapping type indicates B, the HARQ-ACK of the PDSCH may be included in the semi-static HARQ-ACK codebook corresponding to an indicator value of 1.

[0156] According to yet another aspect, a terminal may determine which semi-static HARQ-ACK codebook corresponds to which indicator value the HARQ-ACK for each PDSCH is included in, based on the index of a time domain resource assignment field indicated in the PDCCH (or DCI). For example, the HARQ-ACK for a PDSCH indicated by the indexes 0 to 7 (bits 0000 to 0111) may be included in the semi-static HARQ-ACK codebook corresponding to the indicator value 0, and the HARQ-ACK for a PDSCH indicated by the remaining indexes 8 to 15 (bits 1000 to 1111) may be included in the semi-static HARQ-ACK codebook corresponding to the indicator value 1.

[0157] According to yet another aspect, when a base station configures a semi-static HARQ-ACK codebook for a specific indicator value in a terminal, the base station may configure the number of HARQ-ACKs (or PDSCHs) required per slot. 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 indicator value. In other words, the terminal expects to receive up to two PDSCHs (when there is one bit per PDSCH) indicated by the specific indicator value in one slot. The number of HARQ-ACKs (or PDSCHs) required per slot may be configured with different values ​​in semi-static HARQ-ACK codebooks corresponding to different indicator values.

[0158] According to yet another aspect, the terminal may configure a HARQ-ACK codebook for a specific indicator value using a semi-static HARQ-ACK codebook method, and configure a HARQ-ACK codebook for another specific indicator value using a dynamic HARQ-ACK codebook method.

[0159] According to yet another aspect, if a terminal receives only one PDSCH having a specific 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.

[0160] According to yet another aspect, when a terminal receives PUCCH resource indicator (PRI) configuration information from a base station, the terminal may receive indicator configuration information corresponding to each PRI value. For example, assume that the indicator can have four values, such as 0, 1, 2, and 3, and the terminal receives 16 PUCCH configurations and PRI value (=0, 1, ..., 15) configurations from the base station. In this case, the base station may configure the terminal with an indicator value of 0, 1, 2, or 3 when configuring each PUCCH configuration and PRI value. That is, an indicator value of 0 may be configured for PRI values ​​0, 1, 2, and 3; an indicator value of 1 may be configured for PRI values ​​4, 5, 6, and 7; an indicator value of 2 may be configured for PRI values ​​8, 9, 10, and 11; and an indicator value of 3 may be configured for PRI values ​​12, 13, 14, and 16. The terminal can determine the indicator value based on the PRI value of the DCI that schedules the PDSCH. In the above example, if the DCI PRI value is 10, the terminal knows that the indicator value is 2.

[0161] The operation of the UE generating and transmitting the first and second HARQ-ACK codebooks in step S1210 corresponds to the operation of the processor 110 in FIG.

[0162] The terminal determines whether or not a collision occurs when transmitting a plurality of PUCCHs (S1215). The first PUCCH and the second PUCCH, to which the first HARQ-ACK codebook and the second HARQ-ACK codebook are respectively mapped, are assigned PRIs according to a specific rule.

[0163] For example, referring to Figure 13, the PUCCH resources for transmitting HARQ-ACKs for two PDSCHs with an indicator value of 0 may be determined by the PRI indicated in the PDCCH (or DCI) that is scheduled later among the two PDSCHs. Similarly, the PUCCH resources for transmitting HARQ-ACKs for two PDSCHs with an indicator value of 1 may be determined by the PRI indicated in the PDCCH (or DCI) that is scheduled later among the two PDSCHs.

[0164] If the PUCCH resources indicated by the two PRI values ​​do not overlap, the terminal can determine that the two PUCCHs will not collide in one slot. On the other hand, as shown in Figure 14, if the resources of PUCCHs 1420 and 1430 corresponding to two PRI values ​​(or different indicator values) overlap in the subsequent slot 1410, the terminal can determine that a collision will occur in the transmission of the two PUCCHs.

[0165] Therefore, the terminal transmits at least one of the first PUCCH and the second PUCCH to the base station in the same slot based on the indicator corresponding to each PUCCH (S1220).

[0166] That is, if a collision occurs in step S1215, neither of the two PUCCHs can be transmitted. That is, when a terminal transmits two PUCCHs in one slot, if the resource of the PUCCH corresponding to indicator value 0 overlaps with the resource of the PUCCH corresponding to indicator value 1, the terminal cannot transmit both PUCCHs simultaneously. Here, the overlapping resource may be a time and / or frequency resource.

[0167] In this case, the terminal may drop either the first PUCCH corresponding to indicator value 0 or the second PUCCH corresponding to indicator value 1 and transmit the other PUCCH, or may multiplex the HARQ-ACK codebooks of the first PUCCH corresponding to indicator value 0 and the second PUCCH corresponding to indicator value 1 and transmit them in one PUCCH. Dropping may also be expressed in other terms such as suspending, discarding, and postponing. Such operations will be described below with more specific examples.

[0168] For example, the terminal may select or determine which of the two PUCCHs to transmit based on the indicator value. Specifically, a method for determining whether to drop one of the two PUCCHs and transmit the other PUCCH is as follows.

[0169] In one aspect, a terminal transmits a PUCCH corresponding to a first indicator value (e.g., 0) and drops a PUCCH corresponding to a second indicator value (e.g., 1). Here, an indicator value of 0 may be considered to have a higher priority than an indicator value of 1. Of course, which of the indicator values ​​0 and 1 has a higher priority may be determined differently. Here, the priority of the PUCCH may be determined differently depending on the type of traffic or service data carried by the PDSCH associated with each PUCCH. For example, if the PDSCH associated with the first PUCCH carries URLLC-related data and the PDSCH associated with the second PUCCH carries eMBB-related data, the first PUCCH may have a higher priority than the second PUCCH.

[0170] In another aspect, the terminal transmits a PUCCH corresponding to an indicator value according to the last received PDCCH (or DCI), and drops a PUCCH corresponding to any other indicator value.

[0171] In another aspect, of two colliding or overlapping PUCCHs, the PUCCH with the lower code rate (ie, the more reliable) is transmitted, and the other PUCCH is dropped.

[0172] In yet another aspect, of two colliding or overlapping PUCCHs, the PUCCH of the earlier resource is transmitted and the PUCCH of the later resource is dropped. The determination of the precedence of a resource may be based on the last symbol of the resource, and if the last symbols are the same, the resource with the earlier start symbol may be determined as the earlier resource.

[0173] In yet another aspect, of two colliding or overlapping PUCCHs, the PUCCH occupying the longer symbols is transmitted, and the PUCCH occupying the shorter symbols is dropped. That is, the PUCCH to be transmitted and the PUCCH to be dropped can be determined based on the length (number of symbols) occupied by the PUCCH.

[0174] In yet another aspect, of two colliding or overlapping PUCCHs, the PUCCH with the smaller PRI value is transmitted, and the PUCCH with the larger PRI value is dropped. That is, the PUCCH to be transmitted and the PUCCH to be dropped can be determined based on the PRI value of the PUCCH.

[0175] As another example, the terminal may multiplex the HARQ-ACK codebooks of two PUCCHs and then transmit them on one PUCCH. In order to transmit two HARQ-ACK codebooks mapped to two PUCCHs on one PUCCH, the terminal may process or modify the HARQ-ACK codebook according to the following embodiment.

[0176] In one aspect, the terminal may concatenate the HARQ-ACK codebooks consecutively according to the order of the indicator values ​​to generate one large merged HARQ-ACK codebook, and transmit the HARQ-ACK codebook on one PUCCH.

[0177] In another aspect, the terminal may create a new HARQ-ACK codebook for PDSCH candidates for two colliding or overlapping PUCCHs (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates) and transmit the HARQ-ACK codebook on one PUCCH. Alternatively, the terminal may concatenate the HARQ-ACK codebooks consecutively according to the order of the indicator values ​​to generate one large merged HARQ-ACK codebook, and may exclude HARQ-ACK bits included in a previous HARQ-ACK codebook from a subsequent HARQ-ACK codebook. An advantage of this example is that when HARQ-ACK bits for one PDSCH candidate exist in both of the two overlapping PUCCHs, they do not need to be transmitted redundantly.

[0178] The operation of determining whether collision occurs when the UE transmits multiple PUCCHs in step S1215 corresponds to the operation of the processor 110 in FIG.

[0179] Also, the operation of the terminal transmitting at least one of the first PUCCH and the second PUCCH to the base station in the same slot based on the indicator corresponding to each PUCCH in step S1220 corresponds to the operation of the communication module 120 in Fig. 11. Also, the operation of the base station receiving at least one of the first PUCCH and the second PUCCH from the terminal in the same slot based on the indicator corresponding to each PUCCH in step S1220 corresponds to the operation of the communication module 220 in Fig. 11.

[0180] Timing design of PDSCH and HARQ-ACK when multiple PUCCHs are transmitted in one slot (finer k1 granularity)

[0181] In order to instruct the terminal in which slot to transmit the HARQ-ACK for the PDSCH, the base station can transmit to the terminal a PDCCH (or DCI) scheduling the PDSCH including a k1 value (PDSCH-to-HARQ_feedback timing indicator). The k1 value is indicated in the PDSCH-to-HARQ_feedback timing indicator field of the PDCCH (or DCI) and is the interval (= number of slots) between the slot in which the scheduled PDSCH ends and the slot in which the PUCCH for the HARQ-ACK is transmitted. However, if the k1 value is in slots, there is ambiguity in defining the timing of transmitting two or more HARQ-ACKs (or PUCCHs) within one slot.

[0182] Therefore, in this embodiment, in order to transmit multiple PUCCHs related to multiple HARQ-ACKs in one slot, the unit (or granularity) of the k1 value is defined as a sub-slot, which is a unit smaller than a basic slot. For example, as shown in FIG. 15, the unit of k1 may be defined as half a basic slot. In this case, one basic slot includes two half slots (k-1, k). Therefore, the k1 value is defined as the number of half slots included between the half slot k where the scheduled PDSCH ends and the half slot n where the PUCCH in which the HARQ-ACK is transmitted is transmitted.

[0183] In this case, the interval between the reception timing of the PDSCH and the transmission timing of the HARQ-ACK codebook for the PDSCH may be defined as a number (= b) of symbols that is less than the number (= a) of symbols that make up one slot.

[0184] For example, when the unit of the k1 value is given as a subslot (or a set of symbols), the k1 value represents the number of subslots between the subslot including the last symbol of the PDSCH and the subslot including the first symbol of the PUCCH. For example, if the k1 value is 0, it indicates that the subslot including the last symbol of the PDSCH and the subslot including the first symbol of the PUCCH are the same.

[0185] As another example, when the unit of the k1 value is given as a subslot (or symbol set), the k1 value represents the number of subslots between the last subslot of the slot including the last symbol of the PDSCH and the subslot including the first symbol of the PUCCH. For example, if the k1 value is 0, it indicates that the last subslot of the slot including the last symbol of the PDSCH coincides with the subslot including the first symbol of the PUCCH.

[0186] As another example, when the unit of the k1 value is given as a subslot (or symbol set), the k1 value is set to T from the last symbol of the PDSCH. proc,1 represents the number of sub-slots between the first sub-slot and the sub-slot containing the first symbol of PUCCH after time T proc,1 represents the minimum time it takes for a terminal to receive a PDSCH and transmit a valid HARQ-ACK. proc,1 The value of can be found in the 3GPP TS38.214 document.

[0187] In this way, when the unit of k1 value is given as a sub-slot (or symbol set), if a situation occurs in which multiple PUCCHs overlap within one slot, the operation of the terminal will be explained as follows: This relates to a method of transmitting PUCCHs in a situation in which PUCCH resources designated as half slots (or k1 units) overlap.

[0188] FIG. 16 is a diagram illustrating a situation where multiple PUCCH transmissions collide within one slot according to an example.

[0189] 16, when a PUCCH starting from a preceding half slot (indexed with an indicator value=0, 1620) overlaps with a PUCCH starting from a following half slot (indexed with an indicator value=1, 1630), the terminal cannot transmit both PUCCHs simultaneously. In this case, the terminal can drop one of the two PUCCHs and transmit the other PUCCH, or transmit the HARQ-ACK codebooks for both PUCCHs in one PUCCH.

[0190] For example, the UE may determine which of the two PUCCHs to transmit based on the indicator value. Specifically, a method for determining whether to drop one of the two PUCCHs and transmit the other PUCCH is as follows.

[0191] In one aspect, the UE transmits a PUCCH corresponding to a first indicator value (e.g., 0) and drops a PUCCH corresponding to a second indicator value (e.g., 1). Here, the indicator value 0 may be considered to have a higher priority than the indicator value 1. Of course, the higher priority of the indicator values ​​0 and 1 may be determined differently.

[0192] In another aspect, the terminal transmits a PUCCH corresponding to an indicator value according to the last received PDCCH (or DCI), and drops a PUCCH corresponding to any other indicator value.

[0193] In another aspect, of two colliding or overlapping PUCCHs, the PUCCH with the lower code rate (ie, the more reliable) is transmitted, and the other PUCCH is dropped.

[0194] In yet another aspect, of two colliding or overlapping PUCCHs, the PUCCH of the earlier resource is transmitted and the PUCCH of the later resource is dropped. The determination of the precedence of a resource may be based on the last symbol of the resource, and if the last symbols are the same, the resource with the earlier start symbol may be determined as the earlier resource.

[0195] In yet another aspect, of two colliding or overlapping PUCCHs, the PUCCH occupying the longer symbols is transmitted, and the PUCCH occupying the shorter symbols is dropped. That is, the PUCCH to be transmitted and the PUCCH to be dropped can be determined based on the length (number of symbols) occupied by the PUCCH.

[0196] In yet another aspect, of two colliding or overlapping PUCCHs, the PUCCH with the smaller PRI value is transmitted, and the PUCCH with the larger PRI value is dropped. That is, the PUCCH to be transmitted and the PUCCH to be dropped can be determined based on the PRI value of the PUCCH.

[0197] As another example, the terminal may multiplex the HARQ-ACK codebooks of two PUCCHs and then transmit them on one PUCCH. In order to transmit two HARQ-ACK codebooks mapped to two PUCCHs on one PUCCH, the terminal may process or modify the HARQ-ACK codebook according to the following embodiment.

[0198] In one aspect, the terminal may concatenate the HARQ-ACK codebooks consecutively in time order to generate one large merged HARQ-ACK codebook, and map the HARQ-ACK codebook to one PUCCH for transmission. For example, the terminal may be configured such that the HARQ-ACK codebook instructed to transmit in a preceding half slot in one slot precedes the HARQ-ACK codebook instructed to transmit in a following half slot.

[0199] In another aspect, the terminal may create a new HARQ-ACK codebook for PDSCH candidates for two colliding or overlapping PUCCHs (i.e., generate a semi-static HARQ-ACK codebook for all PDSCH candidates) and transmit the HARQ-ACK codebook on one PUCCH. Alternatively, the terminal may concatenate the HARQ-ACK codebooks consecutively according to the order of the indicator values ​​to generate one large merged HARQ-ACK codebook, and may exclude HARQ-ACK bits included in an earlier HARQ-ACK codebook from a later HARQ-ACK codebook. An advantage of this example is that when an HARQ-ACK bit for one PDSCH candidate exists in both of the two overlapping PUCCHs, it is not necessary to transmit it redundantly.

[0200] Such an operation in the event of a HARQ-ACK collision according to FIG. 16 may be performed by the processor 110 or the communication module 120 in FIG.

[0201] Subslot configuration method and semi-static HARQ-ACK codebook generation method

[0202] This embodiment relates to a method for dividing a slot into multiple sub-slots.

[0203] For example, when a slot consisting of 14 symbols is divided into two subslots, each subslot may consist of seven consecutive symbols. In this case, the first subslot may include the first seven symbols of the slot, and the second subslot may include the last seven symbols of the slot. Alternatively, when a slot consisting of 14 symbols is divided into two subslots, the first subslot may consist of the odd-numbered symbols of the slot, and the second subslot may consist of the even-numbered symbols of the slot.

[0204] As an example, according to a first method of dividing a slot consisting of K symbols into N subslots, the (K mod N) subslots contain floor(K / N)+1 consecutive symbols, and the N-(K mod N) subslots contain floor(K / N) consecutive symbols.

[0205] In one aspect, among the N subslots, the (K mod N) subslots with one more symbol may be located at the front of each slot, and the remaining N-(K mod N) subslots with one less symbol may be located at the rear of each slot.

[0206] In another aspect, of the N subslots, N-(K mod N) subslots with one less symbol may be located at the beginning of the slot, and the remaining (K mod N) subslots with one more symbol may be located at the end of the slot.

[0207] In yet another aspect, among the N subslots, (K mod N) subslots with one more symbol and N-(K mod N) subslots with one less symbol may be positioned in the front and back positions of each slot, with each slot being swapped.

[0208] As another example, according to a second method of dividing a slot consisting of K symbols into N subslots, the nth subslot can contain the floor(K / N)*i+nth (i=0, 1, ..) symbol.

[0209] As another example, the UE may divide each slot into multiple subslots based on the configured PDSCH time domain resource assignment information. For example, the subslots may be divided according to the order of the position of the last PDSCH symbol in the PDSCH time domain resource assignment information. Based on the order of the last PDSCH symbols, the first A PDSCH symbols up to the last symbol may be divided into the first subslot. Then, the remaining subslots may be divided using the same method.

[0210] As another example, the UE may divide each slot into multiple subslots based on the information of symbols occupied by the configured PUCCH. For example, the subslots may be divided according to the order of the positions of the last symbols of the PUCCHs in the information of symbols occupied by the PUCCHs. In terms of order, the first A PUCCH symbols up to the last symbol may be divided into the first subslot. Then, the remaining subslots may be divided using the same method.

[0211] This embodiment also discloses a method for generating a semi-static HARQ-ACK codebook when the unit of the k1 value is set to be a sub-slot (or a set of symbols). The method for generating a semi-static HARQ-ACK codebook according to this embodiment may correspond to the operation of the processor 110 or the communication module 120 in FIG. 11.

[0212] FIG. 17 is a diagram illustrating multiple PDSCH candidates that can be transmitted across a sub-slot according to one example.

[0213] Referring to Figure 17, assume that there are three PDSCH candidates in one slot. The first subslot (sub-slot 0) contains PDSCH candidate #1. If the last symbol of a PDSCH candidate is contained in a specific subslot, the PDSCH candidate can be considered to be contained in the specific subslot. Meanwhile, the second subslot (sub-slot 1) contains PDSCH candidate #2 and PDSCH candidate #3. PDSCH candidate #1 and PDSCH candidate #2 overlap over the same symbol in the first subslot (sub-slot 0), but PDSCH candidate #3 does not overlap with the other PDSCH candidates.

[0214] If a terminal can receive only one PDSCH in one symbol, the combinations of PDSCH candidates that the terminal can receive in the slot of Figure 17 are {PDSCH candidate #1}, {PDSCH candidate #2}, {PDSCH candidate #3}, {PDSCH candidate #1, PDSCH candidate #3}, and {PDSCH candidate #2, PDSCH candidate #3}. That is, the number of PDSCH candidates that the terminal can simultaneously receive in the slot of Figure 17 is up to two. Here, assuming that one HARQ-ACK bit is generated and transmitted for one PDSCH candidate, it can be seen that in this embodiment, the number of HARQ-ACK bits that must be included in the semi-static HARQ-ACK codebook for PDSCH candidates that the terminal can receive in the slot is two.

[0215] However, if the unit of k1 is given as half-slot, the UE generates a semi-static HARQ-ACK codebook for each half-slot. An example of a process for generating a semi-static HARQ-ACK codebook based on half-slots is shown in FIG.

[0216] Referring to FIG. 18, first, the PDSCH combination receivable in the first half slot (sub-slot 0) is {PDSCH candidate #1}, and there is a maximum of one. Therefore, the UE must include a 1-bit HARQ-ACK 1810 in the semi-static HARQ-ACK codebook for the first half slot. Next, the PDSCH combinations receivable in the second half slot (sub-slot 1) are {PDSCH candidate #2}, {PDSCH candidate #3}, and {PDSCH candidate #2, PDSCH candidate #3}, and there are a maximum of two. Therefore, the UE must include a 2-bit HARQ-ACK 1820 in the semi-static HARQ-ACK codebook for the second half slot (sub-slot 1). As a result, the UE must include a total of 3-bit HARQ-ACKs 1810 and 1820 in the semi-static HARQ-ACK codebook for one slot. However, as described above, since a maximum of two PDSCHs can be transmitted in one slot, an unnecessary overhead of one bit occurs compared to the situation where a two-bit HARQ-ACK is included in a semi-static HARQ-ACK codebook. Therefore, a method for reducing this overhead is required.

[0217] According to this embodiment, the HARQ-ACK codebook for PDSCH may be configured to include the same number of HARQ-ACKs as the maximum number of PDSCHs that can be received in one slot. That is, the terminal can generate a HARQ-ACK codebook that includes the same number of HARQ-ACKs as the maximum number of PDSCHs that can be received in one slot.

[0218] For example, when the k1 value is in units of subslots (or symbol sets), the terminal collects all subslots included in one slot and generates a semi-static HARQ-ACK codebook using the PDSCH candidates included in these subslots. That is, the terminal may generate a semi-static HARQ-ACK codebook to be transmitted in subslot n as shown in FIG. 19. The operation of FIG. 19 may correspond to the operation of processor 110 or communication module 120 of FIG. 11.

[0219] FIG. 19 illustrates another example of a process for generating a semi-static HARQ-ACK codebook based on half slots.

[0220] 19, the terminal extracts the maximum k1 value (=k1_max) from a set k1_set of k1 values ​​that can be instructed by the base station. If the index of the slot including the subslot corresponding to n-(k1_max) is X and N_subslots are configured in one slot, then X=floor((n-k1_max) / N_subslot).

[0221] The terminal extracts the k1 value indicating the subslot included in slot X from k1_set. That is, when the element of the k1 set is k1_value, the terminal extracts all k1_values ​​that satisfy X=floor((n-k1_value) / N_subslot). The set of k1 values ​​(including k1_max) extracted in the above process is called k1_max_set. The process of extracting the k1 value from k1_set and constructing k1_max_set in this way is called step S1900.

[0222] Meanwhile, let R be a set of PDSCH candidates that can be received in one slot. If the last symbol of a PDSCH candidate included in set R is included in one of the subslots included in k1_max_set, the UE keeps the PDSCH candidate in set R; otherwise, the UE removes the PDSCH candidate from set R. Also, if the 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 UE removes the PDSCH candidate from set R. This process of removing PDSCH candidates from set R according to a certain criterion is referred to as step S1905.

[0223] The terminal performs the following steps A and B for the PDSCH candidates included in set R.

[0224] A. The terminal allocates one new bit to the PDSCH candidate whose last symbol is at the top. If there is a PDSCH candidate in set R that overlaps with the PDSCH candidate by even one symbol, the terminal allocates the PDSCH candidate to the same bit position as the PDSCH candidate whose last symbol is at the top. The terminal then excludes the PDSCH candidate (including the PDSCH candidate whose last symbol is at the top) from set R. The process of performing step A is referred to as step S1910.

[0225] B. The terminal repeats step A until set R becomes an empty set (S1915).

[0226] The terminal repeats steps S1900, S1905, and S1910 until k1_set becomes an empty set. As a result, the terminal can assign one HARQ-ACK (index 1) to PDSCH candidate #1 or PDSCH candidate #2, and assign another HARQ-ACK (index 2) to PDSCH candidate #3, as shown in FIG.

[0227] Such steps according to FIG. 19 may be performed by processor 110 of FIG.

[0228] ·HARQ-ACK multiplexing indicator

[0229] According to this embodiment, a method for configuring, transmitting, and receiving a HARQ-ACK multiplexing indicator is provided. The method for configuring a HARQ-ACK multiplexing indicator disclosed throughout this specification may be performed by the processor 110 of FIG. 11, the method for generating and transmitting a HARQ-ACK multiplexing indicator may be performed by the communication module 120 of FIG. 11, and the method for receiving a HARQ-ACK multiplexing indicator may be performed by the communication module 220 of FIG. 11.

[0230] A terminal may receive information regarding whether to multiplex the HARQ-ACK of the PDSCH with other HARQ-ACKs from a PDCCH (or DCI) that schedules a PDSCH. In this specification, this information is referred to as a HARQ-ACK multiplexing indicator. The HARQ-ACK multiplexing indicator may be 1 bit. When the HARQ-ACK multiplexing indicator is 1 bit, if the HARQ-ACK multiplexing indicator is 0, it indicates that the HARQ-ACK of the PDSCH is not multiplexed with the HARQ-ACKs of other PDSCHs for transmission, and if the HARQ-ACK multiplexing indicator is 1, it indicates that the HARQ-ACK of the PDSCH is multiplexed with the HARQ-ACKs of other PDSCHs for transmission.

[0231] Here, not multiplexing a specific HARQ-ACK with the HARQ-ACK of another PDSCH means that the PUCCH in which the specific HARQ-ACK is included and transmitted does not include HARQ-ACK information of the other PDSCH. Therefore, a PUCCH in which the HARQ-ACK is not multiplexed includes 1 bit of HARQ-ACK (or 2 bits if the PDSCH is configured to transmit two transport blocks), and the HARQ-ACK may be transmitted in either PUCCH format 0 or PUCCH format 1 according to the bit size. On the other hand, multiplexing a specific HARQ-ACK with the HARQ-ACK of another PDSCH and transmitting it means that the PUCCH in which the specific HARQ-ACK is included and transmitted may include HARQ-ACK information of the other PDSCH.

[0232] When a specific HARQ-ACK is multiplexed with the HARQ-ACK of another PDSCH for transmission, the terminal generates a HARQ-ACK codebook using a dynamic HARQ-ACK codebook or a semi-static HARQ-ACK codebook method, maps it to the PUCCH, and transmits it.

[0233] FIG. 21 illustrates PUCCH transmission by a terminal using a HARQ-ACK multiplexing indicator according to an example.

[0234] 21, a terminal receives a total of four PDSCHs 2101, 2102, 2103, and 2104 in a preceding slot 2100. Each PDSCH corresponds to a specific value of the HARQ-ACK multiplexing indicator. For example, the first PDSCH 2101 and the second PDSCH 2102 may correspond to a HARQ-ACK multiplexing indicator value of 1, and the third PDSCH 2103 and the fourth PDSCH 2104 may correspond to a HARQ-ACK multiplexing indicator value of 0.

[0235] The HARQ-ACK information of two PDSCHs 2101 and 2102, whose HARQ-ACK multiplexing indicators have a value of 1, is transmitted on one PUCCH 2111. The HARQ-ACK information of two PDSCHs 2103 and 2104, whose HARQ-ACK multiplexing indicators have a value of 0, is transmitted on separate PUCCH resources 2112 and 2113, respectively.

[0236] Here, the PUCCH resources for PDSCHs 2103 and 2104 whose HARQ-ACK multiplexing indicator value is 0 are indicated by the PRI value that schedules the PDSCHs 2103 and 2104. If PUCCHs transmitting HARQ-ACKs of individual PDSCHs whose HARQ-ACK multiplexing indicator value is 0 (multiplexing with HARQ-ACKs of other PDSCHs is not possible) overlap in the same symbol, simultaneous transmission is not possible. In this case, the method for processing the PUCCHs is as follows.

[0237] For example, the terminal may multiplex and transmit HARQ-ACK information of PUCCHs in one PUCCH.

[0238] As another example, the terminal prioritizes the HARQ-ACK of a later scheduled PDSCH (i.e., when the PDCCH that schedules the PDSCH starts or ends late) and transmits the PUCCH of the PDSCH, and drops other overlapping PUCCHs without transmitting them.

[0239] As yet another example, the terminal may not expect the two PUCCHs to overlap in one symbol.

[0240] As another example, even if the value of the HARQ-ACK multiplexing indicator is 0 (multiplexing with the HARQ-ACK of another PDSCH is not possible), the UE may be configured to be able to perform partial HARQ-ACK multiplexing. For example, if two PDSCHs 2103 and 2104, each of which has a HARQ-ACK multiplexing indicator value of 0, are instructed to be transmitted on the same PUCCH resource (or have the same PRI value or overlap in at least one symbol), the HARQ-ACKs of the two PDSCHs 2103 and 2104 may be multiplexed and transmitted. In this case, the HARQ-ACK bit of the PDSCH scheduled later is located next to the HARQ-ACK bit of the PDSCH scheduled earlier. This is shown in FIG. 22.

[0241] FIG. 22 shows PUCCH transmission by a terminal using a HARQ-ACK multiplexing indicator according to another example.

[0242] First, referring to (a) of FIG. 22, even if the value of the HARQ-ACK multiplexing indicator for the third and fourth PDSCHs 2103 and 2104 is indicated as 0 in the preceding slot 2200 (i.e., multiplexing is deactivated), if the PRI values ​​of the third and fourth PDSCHs 2103 and 2104 are the same as i, the terminal can transmit HARQ-ACKs for the two PDSCHs on the PUCCH resource corresponding to PRI=i.

[0243] Meanwhile, referring to (b) of FIG. 22, if the value of the HARQ-ACK multiplexing indicator for the third and fourth PDSCHs 2103 and 2104 is indicated as 0 in the preceding slot 2200, and the PRI values ​​of the third and fourth PDSCHs 2103 and 2104 are different from each other (i and j), the terminal can transmit each HARQ-ACK information on the PUCCH resource corresponding to each PRI value.

[0244] Meanwhile, a PUCCH resource for transmitting the HARQ-ACK of a PDSCH whose HARQ-ACK multiplexing indicator has a value of 1 may overlap with a PUCCH resource for transmitting the HARQ-ACK of a PDSCH whose HARQ-ACK multiplexing indicator has a value of 0. In this case, the terminal can transmit the PUCCH in the following manner.

[0245] As an example, the terminal can always prioritize and transmit a PUCCH that transmits a HARQ-ACK for a PDSCH whose HARQ-ACK multiplexing indicator value is 0, and drop a PUCCH that transmits a HARQ-ACK for a PDSCH whose HARQ-ACK multiplexing indicator value is 1.

[0246] As another example, if the last symbol of a PUCCH transmitting a HARQ-ACK of a PDSCH with a HARQ-ACK multiplexing indicator value of 1 precedes or ends at the same time as the last symbol of a PUCCH transmitting a HARQ-ACK of a PDSCH with a HARQ-ACK multiplexing indicator value of 0, the terminal can attach the HARQ-ACK bit of a PDSCH with a HARQ-ACK multiplexing indicator value of 0 to the HARQ-ACK bit of a PDSCH with a HARQ-ACK multiplexing indicator value of 1 and transmit it on the PUCCH resource of the PDSCH with a HARQ-ACK multiplexing indicator value of 1.

[0247] In this specification, for convenience, the HARQ-ACK multiplexing indicator is represented as one bit and described as being explicitly transmitted, but the HARQ-ACK multiplexing indicator may also be indicated implicitly as follows.

[0248] As an example, the UE may determine the HARQ-ACK multiplexing indicator based on the RNTI scrambled in the PDCCH. For example, if the PDCCH (or DCI) scheduling the PDSCH is scrambled with the C-RNTI, the UE may determine that the HARQ-ACK multiplexing indicator of the PDSCH has a value of 1 (i.e., multiplexing with HARQ-ACK information of other PDSCHs is possible). On the other hand, if the PDCCH (or DCI) scheduling the PDSCH is scrambled with another RNTI (e.g., an RNTI for a URLLC service) instead of the C-RNTI, the UE may determine that the HARQ-ACK multiplexing indicator of the PDSCH has a value of 0 (multiplexing with HARQ-ACK information of other PDSCHs is not possible).

[0249] As another example, the UE may determine the HARQ-ACK multiplexing indicator based on 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, or the timing of the PDSCH and the HARQ-ACK. Therefore, for a PDSCH for a URLLC service, it is generally necessary to indicate or transmit the HARQ-ACK earlier. Therefore, if the k1 value is smaller than a predetermined specific k1 value, the UE may determine the HARQ-ACK multiplexing indicator as 0. On the other hand, if the k1 value is greater than or equal to the predetermined specific k1 value, the UE may determine the HARQ-ACK multiplexing indicator as 1. Here, the predetermined specific k1 value may be determined in slot units (e.g., 1 slot or 2 slots), in subslot units, or in absolute time units (e.g., 0.5 ms or 0.25 ms). Alternatively, when a specific k1' value is indicated among multiple k1 values, the terminal may determine that the HARQ-ACK multiplexing indicator value is 0. That is, when the k1' value is indicated, the terminal transmits only HARQ-ACK for one PDSCH without multiplexing the HARQ-ACK codebook.

[0250] As another example, the UE may determine the HARQ-ACK multiplexing indicator based on a modulation and coding scheme (MCS) value. Here, the MCS value indicates the coding rate of the scheduled PDSCH. High reliability is generally required for the PDSCH of the URLLC service. Therefore, if the coding rate value is lower than a specific coding rate value, the UE may determine the HARQ-ACK multiplexing indicator to be 0. On the other hand, if the coding rate value is greater than or equal to the specific coding rate value, the UE may determine the HARQ-ACK multiplexing indicator to be 1. Alternatively, the UE may determine the HARQ-ACK multiplexing indicator based on the MCS table used by the PDCCH (or DCI). If a specific PDCCH (or DCI) uses an MCS table that provides higher reliability (lower coding rate), the UE may determine the value of the HARQ-ACK multiplexing indicator of the PDCCH (or DCI) to be 0.

[0251] As yet another example, the terminal may determine that the HARQ-ACK multiplexing indicator is 0 or 1 based on a combination of specific values ​​indicated by other fields transmitted in the DCI.

[0252] As yet another example, the UE may determine the value of the HARQ-ACK multiplexing indicator based on the search space (or CORESET) in which the PDCCH (or DCI) is detected. For example, the base station may separately instruct the UE of a search space (or CORESET) for URLLC transmission. If the UE receives a PDCCH (or DCI) in the search space (or CORESET), the UE may determine the value of the HARQ-ACK multiplexing indicator to be 0. On the other hand, if the UE receives a PDCCH (or DCI) in a search space (or CORESET) other than the search space (or CORESET), the UE may determine the value of the HARQ-ACK multiplexing indicator to be 1. Alternatively, the UE may distinguish search spaces (or CORESET) without any other explicit instruction from the base station. For example, if the monitoring period of a search space (or CORESET) is shorter than a specific period, the UE may determine the search space (or CORESET) as the search space (or CORESET) for URLLC transmission. The specific period may be, for example, one slot.

[0253] As another example, the terminal may determine the value of the HARQ-ACK multiplexing indicator based on the control channel element (CCE) aggregation level of the PDCCH received from the base station. For example, if the CCE aggregation level exceeds a specific value, the terminal may determine the value of the HARQ-ACK multiplexing indicator of the PDCCH to be 0. Meanwhile, the specific CCE aggregation level value may be set to 8 or 16. If the CCE aggregation level is less than or equal to the specific value, the terminal may determine the value of the HARQ-ACK multiplexing indicator of the PDCCH to be 1.

[0254] As yet another example, the terminal may determine the value of the HARQ-ACK multiplexing indicator based on the DCI format (or the length of the DCI). For example, if a compact DCI is configured in the terminal, the terminal may determine that the value of the HARQ-ACK multiplexing indicator for the PDSCH scheduled by the compact DCI is 0. On the other hand, if a compact DCI is not configured in the terminal, the terminal may determine that the value of the HARQ-ACK multiplexing indicator for the PDSCH scheduled by the compact DCI is 1. Here, the compact DCI is a DCI format for scheduling a URLLC PDSCH and may have a payload size smaller than that of a fallback DCI (DCI format 0_0 / 1_0).

[0255] As another example, the terminal may determine the value of the HARQ-ACK multiplexing indicator based on the value of a PUCCH resource indicator (PRI). Here, the PRI transmitted in the PUCCH (or DCI) indicates which PUCCH resource the terminal is to use among the PUCCH resources configured by the base station. If a predetermined specific value is indicated among the PRI values, the terminal may 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, among the PUCCH resources, a PUCCH resource that transmits 2 bits or less of HARQ-ACK information is suitable for transmitting the URLLC HARQ-ACK. Therefore, when the terminal receives a PRI indicating the PUCCH resource, the terminal may determine the value of the HARQ-ACK multiplexing indicator to be 0. Conversely, among the PUCCH resources, those PUCCH resources exceeding 2 bits of HARQ-ACK information are not suitable for transmitting the URLLC HARQ-ACK, so when a PRI indicating such PUCCH resource is received, the terminal can determine that the value of the HARQ-ACK multiplexing indicator is 1.

[0256] As another example, the UE may determine the value of the HARQ-ACK multiplexing indicator based on the HARQ process number. For example, if a predetermined specific value of the HARQ process number is indicated to the UE, the UE may determine the value of the HARQ-ACK multiplexing indicator as 0 and transmit only a HARQ-ACK for one PDSCH.

[0257] As another example, the terminal may determine the value of the HARQ-ACK multiplexing indicator based on the value of the PDSCH group indicator. The PDSCH group indicator is used to simultaneously transmit multiple PUCCHs in one slot. In this case, multiple HARQ-ACK bits may be multiplexed on the same PUCCH resource. If the terminal receives a specific value of the PDSCH group indicator, the terminal may determine the value of the HARQ-ACK multiplexing indicator to be 0 and transmit only a HARQ-ACK for one PDSCH.

[0258] ·How to derive the k1 value

[0259] This embodiment discloses a method for a terminal to derive or analyze the k1 value. The k1 value is the interval or number of slots (or the number of specific units (subslots) smaller than a slot) between the slot where the scheduled PDSCH ends and the slot where the PUCCH for transmitting the HARQ-ACK is transmitted. However, in reality, a terminal requires processing time to receive and decode the PDSCH and generate a PUCCH for transmitting the HARQ-ACK. Therefore, a specific k1 value, for example, k1=0, is a value that is practically impossible for a terminal to process. Therefore, the k1 value 0 is a value that cannot be instructed to a terminal. Therefore, this embodiment discloses a method for defining the k1 value excluding such values ​​that cannot be instructed to a terminal in terms of processing time.

[0260] As an example, the terminal may process the PDSCH from the last symbol of the PDSCH until the PDSCH processing time (T proc,1) can be determined excluding slots that are completely included between the slots. Such excluded slots are called invalid slots. That is, the k1 value according to this embodiment may be defined as the number of valid slots excluding invalid slots among slots between the slot where the scheduled PDSCH ends and the slot where the PUCCH in which the HARQ-ACK is transmitted is transmitted.

[0261] As another example, the terminal may determine the k1 value excluding slots configured as semi-static DL symbols by a higher layer. For example, the terminal may exclude slots configured only with semi-static DL symbols when determining the k1 value. Alternatively, the terminal may exclude slots in which no PUCCH transmission is possible due to semi-static DL symbols when determining the k1 value.

[0262] Meanwhile, invalid slots may include slots in which PUCCH cannot be transmitted due to overlap of the PUCCH resource indicated by the PRI with a semi-static DL symbol. In this case, the k1 value may be defined as 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 transmitted is transmitted, excluding the invalid slots.

[0263] Such a method of deriving or analyzing the k1 value may be performed by the processor 110 of FIG.

[0264] How to determine PUCCH resources when k1 or PRI field is not specified to the terminal

[0265] The PDCCH (or DCI) that schedules the URLLC may not have the k1 or PRI field configured in order to reduce the DCI overhead (or the payload size of the DCI). Therefore, this embodiment discloses a method for determining a PUCCH resource when the k1 or PRI field is not configured in the DCI.

[0266] As an example, when the k1 field (or the PDSCH-to-HARQ_feedback timing indicator field) for a terminal is not configured (or indicated), the slot including the PUCCH resource of the terminal is set to the PDSCH processing time (T proc,1 ) may be determined as the next slot in which PUCCH transmission (instructed by PRI) is possible, excluding the slots that are completely included between the first and second slots.

[0267] As another example, when the k1 field for a terminal is not configured (or indicated), the slot containing the PUCCH resource for the terminal may be determined as the slot that does not overlap with the symbol indicated by the PRI and the semi-static DL symbol.

[0268] As yet another example, when the PRI field for a terminal is not configured (or indicated), the PUCCH resource for the terminal may be determined as the earliest ending PUCCH resource among the PUCCH resources configured in the slot indicated by k1.

[0269] As yet another example, when the PRI field for a terminal is not configured (or indicated), the PUCCH resource for the terminal is allocated for the PDSCH processing time (T proc,1 ) may be determined as the PUCCH resource that ends earliest among the PUCCH resources excluding the PUCCHs that do not satisfy the above condition. Here, the PUCCH resource that overlaps with the semi-static DL symbol may be excluded.

[0270] FIG. 23 is a diagram illustrating a method for determining a PUCCH resource when the k1 and PRI fields are not configured (or indicated) in a terminal according to an example.

[0271] 23, a total of four PUCCH resources (#1, #2, #3, #4) are configured in slot b for the PDSCH of slot a. Among these, PUCCH resource #1 does not satisfy a processing time condition and may be excluded from the PUCCH resources for the terminal. Among the other PUCCH resources #2, #3, and #4, PUCCH resource #3 is the PUCCH resource that finishes earliest, so the terminal may determine PUCCH resource #3 as the PUCCH resource for transmitting HARQ-ACK for the PDSCH.

[0272] Such a method of determining the PUCCH resource may be performed by the processor 110 of FIG.

[0273] HARQ-ACK transmission method for SPS PDSCH

[0274] In a Release 15NR system, the minimum periodicity of a semi-persistent scheduled (SPS) PDSCH is 10 ms. The interval between the PDSCH transmission slot and the PUCCH transmission slot for HARQ-ACK transmission can be up to 16 slots. This setting prevents HARQ-ACKs for two or more SPS PDSCHs from being transmitted in one PUCCH transmission slot. However, Release 16 has been enhanced to allow SPS PDSCH transmission with a periodicity shorter than 10 ms for downlink URLLC services. In this case, a situation may arise in which a terminal transmits HARQ-ACKs for two or more SPS PDSCHs in one PUCCH transmission slot. Therefore, a method for a terminal to transmit HARQ-ACK bits for multiple SPS PDSCHs in one slot needs to be clearly defined.

[0275] This embodiment may include a step in which a terminal receives an SPS PDSCH in a first slot, and if a HARQ-ACK for the SPS PDSCH cannot be transmitted in a second slot that is k1 slots after the first slot, a step in which a transmission timing of the HARQ-ACK for the SPS PDSCH is delayed to another third slot.

[0276] This will be explained in more detail as follows: The DCI for activating the SPS PDSCH may include one k1 value, where the k1 value is indicated in the HARQ feedback timing indicator field from the PDSCH and indicates the interval or slot difference between the slot in which the PDSCH is transmitted and the slot in which the PUCCH is transmitted.

[0277] The UE is scheduled to transmit a PUCCH including a HARQ-ACK in slot n+k1, which is k1 away from slot n in which the SPS PDSCH is transmitted. However, slot n+k1, which is k1 away from slot n in which the SPS PDSCH is transmitted, is not always a slot in which PUCCH transmission is possible. For example, in a TDD system, there may be a situation in which slot n+k1, which is k1 away from slot n in which the SPS PDSCH is transmitted, overlaps with a DL symbol. In this case, the UE cannot transmit a HARQ-ACK for the SPS PDSCH in slot n+k1.

[0278] FIG. 24 is a diagram illustrating a method in which a terminal transmits HARQ-ACK bits for multiple SPS PDSCHs in one slot according to an example.

[0279] Referring to FIG. 24 , if a first SPS PDSCH transmission is scheduled in slot n and PUCCH transmission for the first SPS PDSCH is not possible in slot n+k1, the terminal postpones (postpones) the transmission timing of the HARQ-ACK for the first SPS PDSCH to slot n+P+k1. If PUCCH transmission is possible in slot n+P+k1, the terminal can transmit the HARQ-ACK for the SPS PDSCH. However, if PUCCH transmission is not possible even in slot n+P+k1, the terminal cannot transmit the HARQ-ACK for the first SPS PDSCH. In this case, the terminal further postpones the transmission timing of the HARQ-ACK for the first SPS PDSCH to slot n+2P+k1. In this pattern, the terminal can continue to postpone the transmission timing of the HARQ-ACK for the first SPS PDSCH by P. Here, P may be defined as, for example, the same value as the period of the SPS PDSCH.

[0280] As an example, if PUCCH transmission is possible in slot n+P+k1, the terminal can multiplex and transmit the HARQ-ACK for the SPS PDSCH that was previously unable to be transmitted and the HARQ-ACK for the SPS PDSCH received in slot n+P. That is, the terminal can transmit the PUCCH including the HARQ-ACK in the nearest slot in which the PUCCH including the HARQ-ACK can be transmitted among slots n+i*P+k1 (i=0, 1, . . .) from slot n to which the SPS PDSCH is allocated.

[0281] As another example, the base station may instruct the terminal to use multiple k1 values ​​for transmitting HARQ-ACK for SPS PDSCH. When the base station instructs the terminal to use multiple K1 values ​​(for example, two k1_1 and k1_2), the HARQ-ACK transmission method is as follows: When the slot in which the SPS PDSCH is received is slot n, the PUCCH is transmitted at n+k1_1 if possible. If the PUCCH cannot be transmitted at n+k1_1, the PUCCH is transmitted at n+k1_2.

[0282] As another example, the base station may instruct the terminal to use multiple k1 values ​​for transmitting HARQ-ACK for SPS PDSCH. Among the multiple k1 values, the first k1 value is applied to the first SPS PDSCH, and the second k1 value is applied to the second SPS PDSCH. That is, if T k1 values ​​are configured, the Mth k1 value can be applied to the (i*T+M)th SPS PDSCH.

[0283] According to this embodiment, the terminal's SPS PDSCH reception operation and the operation of transmitting the HARQ-ACK for the SPS PDSCH with a delay of i*P may be performed by the communication module 120 of FIG. 11, and the base station's SPS PDSCH transmission operation and the operation of receiving the HARQ-ACK for the SPS PDSCH with a delay of i*P may be performed by the communication module 220 of FIG. 11.

[0284] How to configure the reduced DCI payload

[0285] This embodiment is a method for reducing the payload size of DCI. To reduce DCI overhead, the k1 or PRI field may be excluded, and other fields may also be excluded in a similar manner. Alternatively, only a portion of the options that the DCI field can indicate may be included. Here, if only a portion of the options that the DCI field can indicate (for example, N options) is included, the bit size of the DCI field is ceil(log2(N)). However, if N is not expressed as a power of 2, the bit size of the DCI field may be ceil(log2(N)). X -N code points are not available, where X is 2 X is the smallest integer such that N is greater than or equal to N. Therefore, to use the remaining code points more efficiently, a method of joint encoding the individual DCI fields can be used.

[0286] As an example, let us assume that the jth DCI field includes Y(j) options (option 0, option 1, ..., option Y(j)). Here, the options are ordered starting from option 0. That is, the top option is option 0. When the terminal receives DCI from the base station, it can determine the number of the option in the jth DCI field it is from the following formula:

[0287] [Number 1] Field(j)=floor(X / Z(j)) mod Y(j)

[0288] Referring to Equation 1,

number

number

[0289] For example, Table 3 below relates to a case where the DCI includes three fields, each of which includes three options. If two bits are required for each field in the DCI, there are a total of three fields, and therefore a total of six bits are required for these fields. However, according to this embodiment, all three field options can be expressed using only five bits. In Table 3, code points 11011 to 11111 may be reserved.

[0290] [Table 3]

[0291] Referring to Table 3, for example, when 01100 (binary) is indicated in the DCI, the terminal can obtain Field (1) = 0, Field (2) = 1, and Field (3) = 1. That is, it can be seen that Field (1), the first field of the DCI, is indicated as option 0, Field (2), the second field of the DCI, is indicated as option 1, and Field (3), the third field of the DCI, is indicated as option 1.

[0292] A method for determining the length of a DCI format is disclosed below. In the 3GPP Release 15NR system, DCI formats of individual lengths may be defined, for example, as follows:

[0293] 1) Fallback DCI within the common search space (DCI format 0_0, 1_0)

[0294] 2) Fallback DCI (DCI format 0_0, 1_0) within the UE-specific search space

[0295] 3) Non-fallback DCI (DCI format 0_1) that schedules PUSCH

[0296] 4) Non-fallback DCI (DCI format1_1) that schedules PDSCH

[0297] However, a terminal can decode up to three DCI formats with different lengths, but cannot simultaneously decode four DCI formats with different lengths. Therefore, if the lengths of the four DCIs according to 1) to 4) are all different, a process of increasing or decreasing the length of some DCI formats to match the lengths of other DCI formats is required. For example, if the lengths of the above four DCI formats are all different, the base station can perform an operation of matching the length of the fallback DCI in the terminal-specific search space to the length of the fallback DCI in the common search space.

[0298] Furthermore, the length of the frequency domain resource assignment (FDRA) field may be different between the fallback DCI in the UE-specific search space and the fallback DCI in the common search space. The length of the FDRA field of the fallback DCI in the common search space is determined by the size of CORESET #0 configured in the cell initial connection phase or the size of the initial DL BWP set in SIB1 (system information). However, the length of the FDRA field of the fallback DCI in the UE-specific search space is determined by the activated DL BWP. According to this embodiment, in order to make the length of the fallback DCI in the UE-specific search space the same as that of the fallback DCI in the common search space, the base station may truncate the most significant bit (MSB) of the FDRA field of the fallback DCI in the UE-specific search space.

[0299] For reference, the base station can configure the lengths of the non-fallback DCI (DCI format 0_1) scheduling the PUSCH and the non-fallback DCI (DCI format 1_1) scheduling the PDSCH to the terminal through RRC signaling. Here, the lengths of the non-fallback DCI scheduling the PUSCH and the non-fallback DCI scheduling the PDSCH may be set to be the same. In case the lengths of the non-fallback DCI (DCI format 0_1) scheduling the PUSCH and the non-fallback DCI (DCI format 1_1) scheduling the PDSCH are the same, the DCI format includes a 1-bit indicator. That is, in the case of a non-fallback DCI scheduling the PUSCH, the 1-bit indicator has a value of 0, and in the case of a non-fallback DCI scheduling the PDSCH, the 1-bit indicator has a value of 1. More specifically, a method of determining up to three DCI formats of different lengths in Release 15 is as follows.

[0300] The first step includes a step in which the terminal or base station determines the length of fallback DCI (DCI formats 0_0, 1_0) in the common search space. Specifically, the terminal or base station determines the length of DCI format (0_0) based on the initial UL BWP, and determines the length of DCI format (1_0) based on the size of CORESET#0 (if the initial DL BWP is not configured) or based on the initial DL BWP (if the initial DL BWP is configured). If the lengths of DCI format 0_0 and DCI format 1_0 are different, the terminal or base station truncates or zero-pads the MSB of the FDRA field of DCI format 0_0 to match the length of DCI format 1_0.

[0301] The second step includes the terminal or base station determining the length of fallback DCI (DCI formats 0_0, 1_0) in the terminal-specific search space. Specifically, the terminal or base station determines the length of DCI format 0_0 based on the activated UL BWP, and determines the length of DCI format 1_0 based on the activated DL BWP. If the lengths of DCI format 0_0 and DCI format 1_0 are different, the terminal or base station truncates or zero-pads the MSB of the FDRA field of DCI format 0_0 to match the length of DCI format 1_0.

[0302] The third step includes a step in which the terminal or base station determines the lengths of the non-fallback DCI (DCI format 0_1) for scheduling the PUSCH and the non-fallback DCI (DCI format 1_1) for scheduling the PDSCH. If the length of DCI format 0_1 ​​is the same as the length of the fallback DCI (DCI formats 0_0, 1_0) in the terminal-specific search space, the terminal or base station inserts a 1-bit "0" into the non-fallback DCI (DCI format 0_1) for scheduling the PUSCH. If the length of DCI format 1_1 is the same as the length of the fallback DCI (DCI formats 0_0, 1_0) in the terminal-specific search space, the terminal or base station inserts a 1-bit "0" into the non-fallback DCI (DCI format 1_1) for scheduling the PDSCH.

[0303] The fourth step involves the terminal or base station checking the length of the DCI format adjusted in steps 1 to 3. If the number of different lengths among all DCIs is three or less, the terminal can decode the DCI, so the lengths are not adjusted any further. On the other hand, if the number of different lengths exceeds three, the lengths are adjusted again in step 5.

[0304] The fifth step includes the terminal or base station adjusting the length of the DCI format to three. To this end, the terminal or base station may remove the one bit added in the third step. Then, the terminal or base station changes the length of the FDRA field of the fallback DCI (DCI formats 0_0, 1_0) in the terminal-specific search space. Specifically, the terminal or base station may determine the length of DCI format (1_0) based on the size of CORESET#0 (if the initial DL BWP is not configured) or may determine it based on the initial DL BWP (if the initial DL BWP is configured). The terminal or base station determines the length of DCI format (0_0) based on the initial UL BWP. Then, if the lengths of DCI format 0_0 and DCI format 1_0 are different, the terminal or base station truncates or zero-pads the MSB of the FDRA field of DCI format 0_0 to match the length of DCI format 1_0.

[0305] The operations of the first to fifth stages described above may be performed by the processor 110 or the processor (210) in FIG.

[0306] According to yet another embodiment of the present specification, a terminal or a base station may configure a DCI format of a new length to support a new URLLC service. This is conveniently referred to as a compact DCI. The length of each field of the compact DCI may be configured by RRC signaling. Therefore, depending on the configuration by RRC signaling, the length of the compact DCI may be configured to be 16 bits shorter than the Release 15 fallback DCI, may be configured to be the same length as the Release 15 fallback DCI, or may be configured to be longer than the Release 15 fallback DCI. According to this embodiment, two new lengths of DCI formats may be defined as follows.

[0307] 5) Compact DCI for scheduling PUSCH

[0308] 6) Compact DCI for scheduling PDSCH

[0309] In order to decode the DCI formats 1), 2), 3), 4), 5), and 6) which have different lengths, the terminal needs to match the lengths of the DCI formats.

[0310] First, assume that a terminal supporting the URLLC service of Release 16 can simultaneously receive DCI formats with three different lengths. In this situation, a method for adjusting or matching the DCI lengths according to this embodiment is as follows.

[0311] As an example, the terminal first matches the sizes of DCI formats in Release 15. That is, the terminal determines DCI formats of up to three different lengths through the above-mentioned steps 1 to 5. Then, the terminal determines the length of the compact DCI as follows:

[0312] For example, if there are three Release 15 DCI formats of different lengths, the compact DCI scheduling PUSCH and the compact DCI scheduling PDSCH may be configured with the length of any one of the previously determined Release 15 DCI formats.

[0313] In one aspect, when the base station configures the compact DCI to the terminal via RRC signaling, the base station can directly inform the terminal of the length that the compact DCI format should have.

[0314] In another aspect, when a base station configures a compact DCI to a terminal through RRC signaling, the base station may indicate the length of the compact DCI by indicating another DCI format having the same length as the compact DCI. For example, the RRC signaling may be 2 bits, and a value of 00 indicates a fallback DCI (DCI format 0_0, 1_0) in the common search space, a value of 01 indicates a fallback DCI (DCI format 0_0, 1_0) in the terminal-specific search space, a value of 10 indicates a non-fallback DCI (DCI format 0_1) that schedules a PUSCH, and a value of 11 indicates a non-fallback DCI (DCI format 1_1) that schedules a PDSCH. That is, the length of the compact DCI may be the same as the length of another DCI format indicated by the RRC signaling.

[0315] In yet another aspect, when a base station configures a compact DCI to a terminal through RRC signaling, the base station may indicate an index corresponding to the same length as the compact DCI among length indices that other DCI formats may have. For example, the lowest index value of the RRC signaling (e.g., “0” when length indices of other DCI formats are given as 0, 1, and 2) corresponds to the DCI format with the shortest length, and the highest index value (e.g., “2” when length indices of other DCI formats are given as 0, 1, and 2) corresponds to the DCI format with the longest length.

[0316] In another aspect, the terminal may not be required to set the length of the compact DCI as a separate RRC signaling. That is, the terminal can determine the length of the entire compact DCI based on the lengths of each field of the compact DCI. Specifically, assume that the lengths of the DCI formats in Release 15 are given as A, B, and C. Here, A < B < C, and let the sum of the lengths of each field of the compact DCI be X. Then, the length of the compact DCI is determined to be the shortest length among the Release 15 DCI formats that are longer than X. If there is no Release 15 DCI format longer than X, it is set to the length of the longest Release 15 DCI format. For example, if A < X < B, then (B - X) bits are added to the compact DCI to make the length B bits. And if C < X, then (X - C) bits are excluded from the compact DCI to make the length C bits.

[0317] The operation of instructing or configuring the length of the compact DCI by RRC signaling as described above may be performed by the communication module 220 in FIG. 11.

[0318] The method for the terminal to adjust the length of the compact DCI is as follows.

[0319] The terminal determines the length of the compact DCI by the RRC signaling. If the sum of the lengths of all fields of the compact DCI is smaller than the length of the DCI format configured by the RRC signaling, the terminal can fill in the missing bits. Here, the filling values may all be 0 or given as the value of the CRC. On the other hand, if the sum of the lengths of all fields of the compact DCI is larger than the length of the DCI format configured by the RRC signaling, the terminal may subtract the excess bits.

[0320] In one aspect, the excess bits may be subtracted from a specific one field. For example, the excess bits may be subtracted from the FDRA field.

[0321] In another aspect, the excess bits may be subtracted from a predetermined number of specific fields in sequence, with one bit subtracted from the MSB of each field. For example, the excess bits may be subtracted from the FDRA field and the TDRA field in sequence, with the MSB of each field subtracted.

[0322] When the terminal subtracts excess bits from a specific field, the specific field may not be reduced to a length below a preset minimum length. That is, the terminal subtracts excess bits from a first field, and when the length of the first field is reduced to the minimum length, the terminal reduces the length of the next second field.

[0323] The method for adjusting the length of the compact DCI by the terminal according to the above embodiment may be performed by the processor 110 in FIG.

[0324] According to this embodiment, the length of the DCI format that the terminal can monitor may be determined by the length of the DCI format in Release 15. Therefore, there is a drawback in that the length of the compact DCI cannot be made shorter than that of the DCI format in Release 15.

[0325] As another embodiment to solve this problem, the terminal first adjusts the size of the Release 15 DCI format. If the Release 15 DCI format has three lengths and the length of the compact DCI is different from the length of the previous Release 15 DCI format, the terminal can adjust the DCI format length by the following procedure. First, the terminal adjusts the lengths of the non-fallback DCI (DCI format 0_1) that schedules the PUSCH and the non-fallback DCI (DCI format 1_1) that schedules the PDSCH to be the same. Here, the DCI format with the smaller length is padded with zeros to adjust it to the DCI format with the longer length. In this way, by adjusting the length of the non-fallback DCI and not adjusting the length of the compact DCI, it is possible to configure and use a compact DCI with a shorter length.

[0326] Also, assuming that step 5 has not been performed, a possible modified embodiment is as follows. The terminal first adjusts the size of the Release 15 DCI format. If the length of the compact DCI configured in the terminal is different from the length of the DCI in the Release 15 DCI format and the total length exceeds three, the terminal performs step 5. That is, the terminal adjusts the length of the fallback DCI (DCI formats 0_0, 1_0) in the terminal-specific search space to the length of the fallback DCI (DCI formats 0_0, 1_0) in the common search space. Thereafter, if the length of the DCI format still exceeds three, the terminal can further perform the DCI length determination method according to steps 1 to 5.

[0327] In yet another example of the present invention, a terminal may receive DCI formats of different lengths for each slot. To this end, a specific embodiment includes a step in which the terminal checks the lengths of up to three DCI formats for each slot. In this case, the terminal may not monitor DCI formats in a specific slot depending on the period of the search space. In this case, the terminal may determine whether the number of length options exceeds three by using only the lengths of the DCI formats to be monitored and not the DCI formats not to be monitored. If the number of length options exceeds three in that slot, the terminal may adjust the length of the DCI format according to the previous embodiment. Since the length of the DCI format in other slots is three or less, it is not necessary to adjust the length of another DCI format.

[0328] Although the methods and systems of the present invention have been described in connection with particular embodiments, some or all of their components or operations may be implemented using a computing system having a general-purpose hardware architecture.

[0329] 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 as 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, components described as distributed may be implemented in a combined form.

[0330] The scope of the present invention should be expressed by the claims set forth below rather than the above detailed description, and all modifications and variations derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims

1. A method for a terminal to transmit a physical uplink control channel (PUCCH) to a base station in a wireless communication system, comprising: generating a first HARQ-ACK codebook associated with a first PUCCH; generating a second HARQ-ACK codebook associated with a second PUCCH; and transmitting the first PUCCH and the second PUCCH simultaneously to the base station in one slot, or transmitting one of the first PUCCH and the second PUCCH to the base station; The first PUCCH and the second PUCCH correspond to a first indicator and a second indicator having different values, respectively; The method, wherein the one PUCCH is determined from the first PUCCH or the second PUCCH based on the first and second indicators.

2. If the first PUCCH corresponds to the first indicator having a value of 0, the second PUCCH corresponds to the second indicator having a value of 1; The method of claim 1, wherein if the first PUCCH corresponds to the first indicator having a value of 1, the second PUCCH corresponds to the second indicator having a value of 0.

3. 10. The method of claim 1, further comprising receiving the first indicator corresponding to the first PUCCH and the second indicator corresponding to the second PUCCH from the base station via a physical downlink control channel or radio resource control (RRC) signaling.

4. The method of claim 1, wherein the first HARQ-ACK codebook is generated in a semi-static manner, and the second HARQ-ACK codebook is generated in a dynamic manner.

5. the step of simultaneously transmitting the first PUCCH and the second PUCCH to the base station in one slot is performed when transmission of the first PUCCH and the second PUCCH does not collide; the step of transmitting one of the first PUCCH and the second PUCCH is performed when transmission of the first PUCCH and the second PUCCH conflicts; The method of claim 1, wherein a case where transmission of the first PUCCH and the second PUCCH collide includes a case where resources for the first PUCCH and resources for the second PUCCH at least partially overlap.

6. The method of claim 5, wherein the step of transmitting one of the first PUCCH and the second PUCCH further comprises the step of multiplexing the first HARQ-ACK codebook and the second HARQ-ACK codebook and mapping the multiplexed codebook to the one PUCCH.

7. receiving at least one physical downlink shared channel (PDSCH) associated with the first PUCCH or the second PUCCH in a slot preceding the one slot; 2. The method according to claim 1, wherein an interval between the reception timing of the PDSCH and the transmission timing of a PUCCH including a HARQ-ACK codebook for the at least one PDSCH is defined as a number (= b) of symbol units that is less than the number (= a) of symbols constituting the one slot or the preceding slot.

8. 8. The method of claim 7, wherein b is half of a.

9. the one slot and the preceding slot each include a plurality of sub-slots; The method of claim 7, wherein the HARQ-ACK codebook for the at least one PDSCH includes a number of HARQ-ACKs equal to the number of maximum PDSCHs receivable in the preceding slot.

10. receiving a semi-persistently scheduled PDSCH in a slot preceding the one slot; If the HARQ-ACK for the semi-statically scheduled PDSCH cannot be transmitted after k1 slots from the preceding slot, the transmission timing of the PUCCH including the HARQ-ACK for the semi-statically scheduled PDSCH is delayed by the one slot; The method according to claim 1, wherein k1 is an interval between the reception timing of the semi-statically scheduled PDSCH and the transmission timing of a PUCCH including a HARQ-ACK for the PDSCH.

11. The method further includes a step of setting a transmission period of the semi-statically scheduled PDSCH from the base station, The method according to claim 10, wherein an interval between the k1 slots from the preceding slot and the one slot is determined to be a multiple of the transmission period.

12. A method for a base station to receive a physical uplink control channel (PUCCH) from a terminal in a wireless communication system, comprising: transmitting a first physical downlink shared channel (PDSCH) and a second PDSCH to the terminal in a first slot; receiving, from the terminal in a second slot, a first PUCCH including a first HARQ-ACK codebook for the first PDSCH and a second PUCCH including a second HARQ-ACK codebook for the second PDSCH simultaneously, or receiving one of the first PUCCH and the second PUCCH from the terminal; The first PUCCH and the second PUCCH correspond to a first indicator and a second indicator having different values, respectively; The method, wherein the one PUCCH is determined from the first PUCCH or the second PUCCH based on the first indicator and the second indicator.

13. If the first PUCCH corresponds to the first indicator having a value of 0, the second PUCCH corresponds to the second indicator having a value of 1; The method of claim 12, wherein if the first PUCCH corresponds to the first indicator having a value of 1, the second PUCCH corresponds to the second indicator having a value of 0.

14. 13. The method of claim 12, further comprising transmitting the first indicator corresponding to the first PUCCH and the second indicator corresponding to the second PUCCH to the terminal via a physical downlink control channel (PDCCH) or radio resource control (RRC) signaling.

15. The method of claim 12, wherein the first HARQ-ACK codebook is generated in a semi-static manner, and the second HARQ-ACK codebook is generated in a dynamic manner.

16. the step of simultaneously receiving the first PUCCH and the second PUCCH from the terminal in the second slot is performed when transmission of the first PUCCH and the second PUCCH does not collide; receiving one of the first PUCCH and the second PUCCH is performed when transmission of the first PUCCH and the second PUCCH conflicts; The method of claim 12, wherein a case where transmission of the first PUCCH and the second PUCCH collide includes a case where resources for the first PUCCH and resources for the second PUCCH at least partially overlap.

17. The method of claim 16, wherein receiving one of the first and second PUCCHs further comprises demultiplexing the one PUCCH to obtain the first and second HARQ-ACK codebooks.

18. 13. The method according to claim 12, wherein an interval between the transmission timing of the first and second PDSCHs and the reception timing of the first and second PUCCHs is defined as a number (= b) of symbols that is smaller than the number (= a) of symbols that constitute the first slot or the second slot.

19. each of the first slots includes a plurality of sub-slots; The method of claim 18, wherein the HARQ-ACK codebook for the first PDSCH includes the same number of HARQ-ACKs as the maximum number of PDSCHs receivable in the first slot.

20. the first PDSCH is a semi-persistently scheduled PDSCH, and a transmission period for the first PDSCH is set by the base station; The spacing between the first slot and the second slot is k1; When the first PUCCH cannot be transmitted in the second slot, the transmission timing of the first PUCCH is delayed to a third slot; The method according to claim 12, wherein k1 is an interval between a reception timing of the first PDSCH and a transmission timing of the first PUCCH.

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