Method, device and system for receiving downlink data and transmitting HARQ-ACK in a wireless communication system

Abstract

To provide: a method for designing and transmitting a codebook for solving a problem that may occur in the case of transmitting HARQ-ACKs in a situation in which PDSCHs and PUCCHs are repeatedly transmitted in a plurality of slots; and a device therefor.SOLUTION: A terminal used in a wireless communication system includes a communication module and a processor for controlling the communication module. The processor is configured to receive a plurality of first DCI formats for downlink scheduling, receive a second DCI format for scheduling of a physical uplink shared channel, and transmit a HARQ-ACK codebook associated with the downlink scheduling.SELECTED DRAWING: Figure 23

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system, and more particularly to a method for transmitting downlink data and an acknowledgement thereto in a wireless communication system. [Background technology]

[0002] 3GPP (registered trademark, the same applies below) LTE(-A) defines uplink / downlink physical channels for transmitting physical layer signals. For example, the Physical Uplink Shared Channel (PUSCH) is a physical channel for transmitting uplink data, the Physical Uplink Control Channel (PUCCH) is a physical channel for transmitting control signals, and the Physical Random Access Channel (PRACH) is a physical channel for transmitting uplink data. The downlink also includes the Physical Downlink Shared Channel (PDSCH) for transmitting data, the Physical Control Format Indicator Channel (PCFICH), the Physical Downlink Control Channel (PDCCH), and the Physical Hybrid ARQ Indicator Channel (PHICH) for transmitting L1 / L2 control signals.

[0003] Among these channels, the downlink control channel (PDCCH / EPDCCH) is a channel through which a base station transmits uplink / downlink scheduling allocation control information, uplink transmission power control information, and other control information to one or more or multiple terminals. Because the resources that a base station can use for PDCCH transmission at one time are limited, it is not possible to assign different resources to each terminal, and the resources must be shared to transmit control information to any terminal. For example, in 3GPP LTE(-A), four resource elements (REs) are bundled to form a resource element group (REG), which then forms nine control channel elements (CCEs). The resources that can be transmitted by combining one or more CCEs are notified to the terminal, and many terminals share and use the CCEs. Here, the number of CCEs that can be combined is called the CCE aggregation level, and the resources to which CCEs are allocated according to the possible CCE aggregation levels are called search spaces. The search space can be a common search space defined for each base station, or a terminal-specific or UE-specific search space defined for each terminal. The UE performs decoding for all possible CCE combinations in the search space and determines whether the PDCCH corresponds to its own PDCCH based on the user equipment (UE) identifier included in the PDCCH. Therefore, such UE operation inevitably takes a long time to decode the PDCCH and consumes a lot of energy.

[0004] Following the commercialization of the 4G communication system, efforts are underway to develop improved 5G or pre-5G communication systems to meet the increasing demand for wireless data traffic. For this reason, 5G or pre-5G communication systems are referred to as beyond-4G network (Beyond 4G Network) or post-LTE (Post-LTE) systems. To achieve high data transmission rates, implementation of 5G communication systems in ultra-high frequency (mmWave) bands (e.g., the 60 GHz band) is being considered. To mitigate propagation path loss and increase propagation distance in ultra-high frequency bands, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antenna technologies are being discussed for 5G communication systems. In addition, to improve the system network, technologies such as advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and receiver interference cancellation are being developed for the 5G communication system.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] Generally, mobile communication systems have been developed to provide voice services while ensuring user activity. However, mobile communication systems have gradually expanded their service areas to include not only voice but also data services, and have now evolved to the point where they can provide high-speed data services. However, due to resource shortages in currently available mobile communication systems and users' demands for higher speed services, a more advanced mobile communication system is required.

[0008] As mentioned above, future 5G technology will require 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 drop to 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 mini-slots, which have an even shorter TTI period (e.g., 0.2 ms) than conventional slots (or subframes).

[0009] Rel-16 enhanced URLLC (eURLLC) discusses various technologies to provide lower latency and higher reliability. Among them, to provide lower latency, it supports transmission of an uplink control channel containing two or more HARQ-ACKs in one slot. A terminal can ensure lower latency by transmitting a HARQ-ACK as soon as possible in response to successful reception of a downlink shared channel. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention relates to a method for designing a semi-static HARQ-ACK codebook and a method for transmitting a PUCCH in a 3GPP NR system, and an object of the present invention is to provide a method and apparatus therefor for solving problems that may occur in a situation where a PDSCH or a PUCCH is repeatedly transmitted in multiple slots.

[0011] The technical problem to be solved by the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present invention pertains from the following description. [Means for solving the problem]

[0012] A terminal of a wireless communication system according to an embodiment of the present invention includes a communication module and a processor for controlling the communication mode, the processor receiving a first PDCCH for scheduling a first physical downlink shared channel (PDSCH), the first PDCCH including a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled up to a serving cell at the time the first PDCCH is monitored and a first total DAI indicating the number of all PDSCHs scheduled in the serving cell at the time the PDCCH is monitored, a second PDCCH for scheduling a second PDSCH, the second PDCCH including a second counter DAI and a second total DAI, receiving the first PDSCH based on the first PDCCH, receiving the second PDSCH based on the second PDCCH, and uplink control information including a HARQ-ACK codebook for the first PDSCH and the second PDSCH. When the number of bits of the first counter DAI is different from the number of bits of the second counter DAI, the value of the second counter DAI is determined based on the number of bits of the first counter DAI.

[0013] In addition, in the present invention, if the number of bits of the first counter DAI is smaller than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI, the number of which is the same as the number of bits of the first counter DAI.

[0014] In addition, in the present invention, if there are multiple values ​​determined by at least one bit of the second counter DAI, the number of which is the same as the number of bits of the first counter DAI, the value of the second counter DAI is determined to be the value among the multiple values ​​that is the least different from the value indicated by the first counter DAI.

[0015] In addition, in the present invention, if the first counter DAI is 1 bit and the second counter DAI is 2 bits, the value of the second counter DAI is determined using the LSB (Least Significant Bit) or MSB (Most Significant Bit) of the 2 bits.

[0016] Furthermore, in the present invention, when one bit of the first counter DAI is "0", if the LSB or the MSB of the second counter DAI is "0", the value of the second counter DAI is determined to be "2", and if the LSB or the MSB of the second counter DAI is "1", the value of the second counter DAI is determined to be "1".

[0017] Furthermore, in the present invention, when one bit of the first counter DAI is "1", if the LSB or MSB of the second counter DAI is "1", the value of the second counter DAI is "1", and if the LSB or MSB of the second counter DAI is "0", the value of the second counter DAI is determined to be "2".

[0018] In addition, in the present invention, if the number of bits of the first counter DAI is greater than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined by expanding the number of bits of the second counter DAI to the same number of bits as the number of bits of the first counter DAI.

[0019] In addition, in the present invention, if there are multiple values ​​of the second counter DAI determined by expanding it to the same number of bits as the number of bits of the first counter DAI, the value of the second counter DAI is determined to be the value among the multiple values ​​that is the least different from the value indicated by the first counter DAI.

[0020] In addition, in the present invention, if the first counter DAI is 2 bits and the second counter DAI is 1 bit, the value of the second counter DAI is determined by expanding 1 bit to 2 bits.

[0021] Furthermore, in the present invention, if two bits of the first counter DAI are "00" or "01" and one bit of the second counter DAI is "0", the second counter DAI is determined to be "3", and if two bits of the first counter DAI are "10" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "1".

[0022] Furthermore, in the present invention, if two bits of the first counter DAI are "01" or "10" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "4", and if two bits of the first counter DAI are "00" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "2".

[0023] Further, the present invention provides a method for scheduling a first physical downlink shared channel (PDSCH), the first PDCCH including a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled in a serving cell at the time the first PDCCH is monitored and a first total DAI indicating the number of all PDSCHs scheduled in the serving cell at the time the PDCCH is monitored, receiving a second PDCCH for scheduling a second PDSCH, the second PDCCH including a second counter DAI and a second total DAI, receiving the first PDSCH based on the first PDCCH, receiving the second PDSCH based on the second PDCCH, and receiving uplink control information including a HARQ-ACK codebook for the first PDSCH and the second PDSCH. and transmitting a value of the second counter DAI to the base station, wherein if the number of bits of the first counter DAI is different from the number of bits of the second counter DAI, the value of the second counter DAI is determined based on the number of bits of the first counter DAI. [Effects of the Invention]

[0024] According to one embodiment of the present invention, a terminal transmits a PUCCH including two or more HARQ-ACKs in one slot, and the number of HARQ-ACKs that each PUCCH may have can be reduced to increase the coverage of the PUCCH.

[0025] Furthermore, according to one embodiment of the present invention, HARQ-ACK information for PDSCHs scheduled according to downlink control information having different formats can be multiplexed and transmitted.

[0026] In addition, according to one embodiment of the present invention, HARQ-ACK information for PDSCHs scheduled by different downlink control information is multiplexed and transmitted, thereby reducing the signaling overhead for transmitting HARQ-ACK information.

[0027] Furthermore, according to one embodiment of the present invention, a HARQ-ACK bit(s) sequence with low overhead of downlink control information (e.g., DCI) is determined, thereby increasing the transmission efficiency of the network between the base station and the terminal.

[0028] 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]

[0029] [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 4] 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 an example of signaling between a terminal and a base station to which an embodiment of the present invention is applied. [Figure 13] 10 is a diagram illustrating an example of a method for a terminal to count the number of PDSCHs transmitted from a base station, based on a pseudo code applied to an embodiment of the present invention. [Figure 14] 1 is a diagram illustrating an example of a method for transmitting HARQ-ACK based on downlink control information having different formats according to an embodiment of the present invention. [Figure 15] FIG. 10 is a diagram illustrating another example of a method for transmitting HARQ-ACK based on downlink control information having different formats according to an embodiment of the present invention. [Figure 16] A diagram showing an example of a method for transmitting HARQ-ACK based on downlink control information for uplink and downlink scheduling according to one embodiment of the present invention. [Figure 17] FIG. 2 is a diagram showing an example of a downlink assignment indicator of each piece of downlink control information detected from a monitoring occasion according to an embodiment of the present invention. [Figure 18] 10 is a diagram illustrating an example of a method for transmitting a HARQ-ACK based on downlink control information having different formats, based on pseudocode according to an embodiment of the present invention. [Figure 19] A figure showing an example of a downlink allocation indicator of each downlink control information detected from a monitoring opportunity according to one embodiment of the present invention. [Figure 20] 10 is a diagram illustrating an example of a method for transmitting a HARQ-ACK for a PDSCH according to a receiving order of a PDCCH according to an embodiment of the present invention. [Figure 21] 10 is a diagram illustrating an example of a method for transmitting a HARQ-ACK for a PDSCH according to time information of the PDSCH according to an embodiment of the present invention. [Figure 22] 10 is a diagram illustrating an example of a method for transmitting a HARQ-ACK for a PDSCH according to a HARQ process ID (or HARQ process number) of a PDCCH that schedules a PDSCH according to an embodiment of the present invention. [Figure 23] 10 is a flowchart illustrating an example of a terminal operation for transmitting a HARQ-ACK based on downlink information having different formats according to an embodiment of the present invention. [Figure 24] 10 is a flowchart illustrating an example of a base station operation for receiving HARQ-ACK based on downlink information having different formats according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] FIG. 1 is a diagram illustrating an example of a radio frame structure used in a radio communication system.

[0035] 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).

[0036] 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.

[0037] There is one resource grid per antenna port. Referring to FIG. 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, the term "symbol" includes OFDM symbols, SC-FDMA symbols, DFTs-OFDM symbols, etc. Referring to FIG. 2, a signal transmitted from each slot is represented by a resource grid consisting of Nsize, μgrid, x*NRBSC subcarriers, and Nslotsymb OFDM symbols. Here, x=DL for a downlink resource grid, and x=UL for an uplink resource grid. 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.

[0038] 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).

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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 means of the cell-specific RRC signal. At this time, the UE-specific RRC signal cannot change the downlink symbol or uplink symbol consisting 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 not configured as either an uplink symbol or a downlink symbol is a flexible symbol.

[0044] 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.

[0045] When 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 index. Next, the terminal receives the physical broadcast channel from the base station and obtains the broadcast information within the cell.

[0046] 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.

[0047] 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).

[0048] 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.

[0049] 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.

[0050] FIG. 4 is a diagram illustrating an SS / PBCH block for initial cell access in a 3GPP NR system.

[0051] 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).

[0052] 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. [Table 1]

[0053] The SS groups a total of 1008 unique physical layer cell IDs (physical layer cell IDs) into 336 physical layer cell ID groups, each containing three unique identifiers, through the combination of three PSSs and SSSs. Specifically, each physical layer cell ID is part of only one physical layer cell ID group. Therefore, the physical layer cell ID NcellID = 3N(1)ID + N(2)ID is uniquely defined by an index N(1)ID ranging from 0 to 335 indicating a physical layer cell ID group and an index N(2)ID ranging from 0 to 2 indicating a physical layer identifier within the physical layer cell ID group. The UE detects the PSS and identifies one of the three unique physical layer identifiers. The UE also detects the SSS and identifies one of the 336 physical layer cell IDs associated with the physical layer identifier. In this case, the PSS sequence dPSS(n) is as follows:

[0054] dPSS(n)=1-2x(m) m=(n+43N(2)ID) mod 127 0≦n<127

[0055] where x(i+7)=(x(i+4)+x(i)) mod 2, Given that [x(6)x(5)x(4)x(3)x(2)x(1)x(0)]=[1110110].

[0056] Also, the SSS sequence dSSS(n) is as follows:

[0057] dSSS(n)=[1-2x0((n+m0) mod 127][1-2xi((n+m1) mod 127] m0=15 floor(N(1)ID / 112)+5N(2)ID m1=N(1)ID mod 112 0≦n<127

[0058] where x0(i+7)=(x0(i+4)+x0(i))mod 2 x1(i+7)=(x1(i+1)+x1(i))mod 2,

[0059] Given that [x0(6)x0(5)x0(4)x0(3)x0(2)x0(1)x0(0)]=[0000001], [x1(6)x1(5)x1(4)x1(3)x1(2)x1(1)x1(0)]=[0000001].

[0060] 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.

[0061] 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.

[0062] FIG. 6 is a diagram showing a CORESET in which a PDCCH is transmitted in a 3GPP NR system.

[0063] 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.

[0064] FIG. 7 is a diagram illustrating a method for configuring a PDCCH search space in a 3GPP NR system.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] Table 2 shows an example of a PUCCH used in a wireless communication system. [Table 2]

[0070] The PUCCH is used to transmit the following uplink control information (UCI):

[0071] - SR (Scheduling Request): Information used to request uplink UL-SCH resources.

[0072] 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.

[0073] 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.

[0074] In the 3GPP NR system, five PUCCH formats are used to support various service scenarios, various channel environments, and frame structures.

[0075] 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 using different RBs in the two symbols. This allows the UE to obtain frequency diversity gain. More specifically, the UE determines a cyclic shift value mcs according to the Mbit-bit UCI (Mbit = 1 or 2), and maps a 12-length base sequence cyclically shifted by the determined mcs value to one OFDM symbol and 12 REs of one PRB for transmission. If the number of cyclic shifts available to the UE is 12 and Mbit = 1, 1-bit UCIs 0 and 1 are represented by sequences corresponding to two cyclic shifts with a cyclic shift value difference of 6. Also, if Mbit=2, then 2-bit UCI 00, 01, 11, 10 is represented by a sequence corresponding to four cyclic shifts with a difference of three between the cyclic shift values.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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 per 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.

[0083] 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.

[0084] FIG. 8 is a conceptual diagram illustrating carrier aggregation.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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).

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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 .

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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 .

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] In an NR wireless communication system, a terminal transmits a codebook including hybrid automatic repeat request (HARQ)-ACK information to signal whether a downlink signal or channel has been successfully received. The HARQ-ACK codebook includes one or more bits indicating whether a downlink channel or signal has been successfully received. Here, the downlink channel includes at least one of a physical downlink shared channel (PDSCH), a semi-persistence scheduling (SPS) PDSCH, and a PDCCH for releasing an SPS PDSCH. HARQ-ACK codebooks are divided into semi-static HARQ-ACK codebooks (or type 1 codebooks) and dynamic HARQ-ACK codebooks (or type 2 coding). The base station configures one of the two HARQ-ACK codebooks for the terminal. The terminal uses the configured HARQ-ACK codebook.

[0115] If a semi-static HARQ-ACK codebook is used, the base station uses RRC signaling to set the number of bits of the HARQ-ACK codebook and information that determines whether each bit of the HARQ-ACK codebook successfully receives which downlink signal or channel. Therefore, the base station does not need to signal information required for transmitting the HARQ-ACK codebook to the terminal every time it needs to transmit the HARQ-ACK codebook.

[0116] If a dynamic HARQ-ACK codebook is used, the base station signals information required for generating the HARQ-ACK codebook via the PDCCH (or DCI). Specifically, the base station signals information required for generating the HARQ-ACK codebook via a Downlink Assignment Index (DAI) field of the PDCCH (or DCI). In a specific embodiment, the DAI indicates the number of HARQ-ACK codebook bits included in the HARQ-ACK codebook and information on which channel or signal each bit of the HARQ-ACK codebook indicates whether the reception is successful. The terminal receives the DAI field via the PDCCH (or DCI) that schedules the PDSCH. The value of the DAI field is divided into counter-DAI and total-DAI. The total DAI indicates the number of downlink signals or channels whose reception is indicated by the HARQ-ACK codebook up to the current monitoring occasion (MO). Counter-DAI indicates a bit of the HARQ-ACK codebook indicating whether or not the downlink signal or channel has been successfully received, among downlink signals or channels for which the success or failure of reception is indicated through the HARQ-ACK codebook up to the current cell at the current monitoring time. The PDCCH (or DCI) scheduling the PDSCH includes a value of Counter-DAI corresponding to the scheduled PDSCH. In addition, the PDCCH (or DCI) scheduling the PDSCH includes a value of Total-DAI corresponding to the scheduled PDSCH. The UE determines the number of bits of the dynamic HARQ-ACK codebook based on information signaled by the PDCCH (or DCI). Specifically, the UE determines the number of bits of the dynamic HARQ-ACK codebook based on the DAI of the PDCCH (or DCI).

[0117] FIG. 12 is a flowchart showing an example of signaling between a terminal and a base station to which an embodiment of the present invention is applied.

[0118] Referring to FIG. 12, in step S12010, the terminal UE receives RRC configuration information including information for receiving downlink control information (DCI) from a base station.

[0119] For example, the RRC configuration information includes information on a control resource set (CORESET) and a search space for the terminal to detect a PDCCH including downlink control information. In this case, the information on the control resource set includes at least one of an identifier (ID) of a control resource set in which the terminal can detect a PDCCH including DCI, configuration information of control channel elements (CCEs), and duration or frequency resource information of the control resource set. In this case, the information on the search space includes at least one of an identifier (ID) of a search space in which the terminal can detect a PDCCH including DCI, a format of DCI detectable from each search space, a detection duration, or resource information.

[0120] Next, the terminal detects the PDCCH from the monitoring occasion based on the RRC configuration information and receives DCI in step S12020. The terminal detects the PDCCH from a specific search space of the monitoring occasion according to the type of service and / or data based on the RRC configuration information and acquires DCI.

[0121] In this case, different bits are set for the DAI included in the DCI depending on the DCI format. For example, in DCI Format 1_0, 2 bits are set for the DAI, and in DCI Format 1_1, 1 bit is set for the semi-static HARQ-ACK codebook and 2 bits are set for the dynamic-HARQ-ACK codebook.

[0122] Table 3 below shows an example of DAI bits in the DCI format. [Table 3]

[0123] Furthermore, the terminal is allocated resources for receiving the PDSCH or transmitting the PUSCH via the PDCCH (or DCI).

[0124] Next, the terminal receives the PDSCH according to the allocated resource or transmits the PUSCH to the base station in S12030. If the terminal receives the PDSCH from the base station, the terminal generates a HARQ-ACK codebook indicating the Ack / Nack of the received PDSCH based on the DAI value included in the PDCCH (or DCI) that schedules the PDSCH, and includes the generated HARQ-ACK codebook in uplink control resources (UCI) and transmits the UCI to the base station in S12040.

[0125] FIG. 13 is a diagram illustrating an example of a method for a terminal to count the number of PDSCHs transmitted from a base station, based on pseudocode applied to an embodiment of the present invention.

[0126] Figures 13(a) and (b) show an example of a method for generating and transmitting a HARQ-ACK codebook based on a stored counter-DAI value, a counter-DAI value transmitted via a specific DCI, and a stored total-DAI value.

[0127] In detail, referring to FIG. 13(a), the UE determines that the counter-DAI value of the PDCCH (or DCI) received from serving cell c at monitoring opportunity m is

number

number

[0128] Here, the monitoring occasion index m and cell index c are omitted. Tables 4 and 5 show the range of values ​​that counter-DAI or total-DAI can represent depending on the number of bits in counter-DAI or total-DAI. Table 4 shows an example where the number of bits in counter-DAI or total-DAI is 2 bits, and Table 5 shows an example where the number of bits in counter-DAI or total-DAI is 1 bit. [Table 4] [Table 5]

[0129] In this case, the pseudocode for generating the HARQ-ACK codebook is shown in Table 6 below. [Table 6-1] [Table 6-2]

[0130] In this case, the terminal uses the pseudo code in Table 6 to execute V temp and V C-DAI、c、m The values ​​are compared to determine whether reception of the PDSCH was missed due to a failure in reception of the PDCCH (or DCI) that schedules the PDSCH transmitted from the base station.

[0131] For example, as shown in Figure 13(a), when a terminal sets a 2-bit counter-DAI, the terminal D =2 2= 4, and find that the range represented by the number of bits of counter-DAI is 1 to 4. When one PDCCH (or DCI) is received, the counter-DAI value (V C-DAI、c、m ) is "1", and V temp If the value of is "4", it is recognized that the PDSCH has been transmitted continuously without missing. However, when the PDCCH (or DCI) is received, the counter-DAI value (V C-DAI、c、m ) is "2" and V temp If the value of counter-DAI is "4", the terminal recognizes that the PDSCH scheduled by the PDCCH (or DCI) with a counter-DAI value of "1" is missing, and displays the HARQ-ACK for this PDSCH as NACK.

[0132] Also, as shown in Figure 13(b), the terminal uses the stored total-DAI value, V temp2 and V temp For example, as shown in (b) of FIG. 13, when the terminal is configured with 2-bit total-DAI, T D =2 2 = 4, the range of the total-DAI expressed in bits is 1 to 4. The total-DAI value (V temp2 ) is "1", and V temp If the value of is "4", it is recognized that a PDSCH has not been missing after the last received PDCCH. However, if the total-DAI value (V temp2 ) is "2" and V temp If the value is "4", it is recognized that a PDSCH scheduled by one PDCCH (or DCI) is missing after the last received PDCCH, and the HARQ-ACK for this PDSCH is displayed as NACK.

[0133] In Table 6, the size of the terminal's final HARQ-ACK codebook is 0 ACK is determined by the value of

[0134] A new DCI format is being introduced to provide ultra-reliable and low-latency communication (URLLC) services. This new DCI format has the feature of being able to set the length of each DCI field to reduce the bit size. Hereinafter, these newly introduced DCI formats will be referred to as DCI format 0_2 and DCI format 1_2.

[0135] DCI format 0_2 is a DCI format for scheduling a PUSCH, and DCI format 1_2 is a DCI format for scheduling a PDSCH.

[0136] In addition, in Rel-16 NR, up to two HARQ-ACK codebooks are generated depending on the service type. For example, one HARQ-ACK codebook is generated by collecting HARQ-ACK information from PDSCHs for eMBB services, and one HARQ-ACK codebook is generated by collecting HARQ-ACK information from PDSCHs for URLLC services. DCI formats 1_0, 1_1, and 1_2 for scheduling PDSCHs should indicate which HARQ-ACK codebook the scheduled HARQ-ACK information is included in. In this case, various methods are used to indicate the HARQ-ACK information.

[0137] For example, a separate 1-bit field is added to the DCI format, where index 1 indicates HARQ-ACK for a PDSCH with a high priority such as a URLLC service, and index 0 indicates HARQ-ACK for a PDSCH with a low priority such as an eMBB service.

[0138] Alternatively, the HARQ-ACK of the PDSCH for URLLC and the HARQ-ACK of the PDSCH for eMBB are distinguished by the following parameters and / or methods.

[0139] That is, the UE generates a HARQ-ACK codebook by distinguishing the HARQ-ACK of the PDSCH for URLLC from the HARQ-ACK of the PDSCH for eMBB based on the different RNTIs of the PDCCH (or DCI) for scheduling the PDSCH for URLLC and the PDCCH (or DCI) for scheduling the PDSCH for eMBB.

[0140] The PDCCH is distinguished by the CORESET in which it is transmitted. That is, the UE generates a HARQ-ACK codebook by distinguishing the HARQ-ACK of the PDSCH for URLLC from the HARQ-ACK of the PDSCH for eMBB based on the CORESET in which the PDSCH for URLLC is transmitted and the CORESET in which the PDSCH for eMBB is transmitted.

[0141] The DCI formats are differentiated. That is, the UE generates HARQ-ACK codebooks by distinguishing between the HARQ-ACK of the PDSCH for URLLC and the HARQ-ACK of the PDSCH for eMBB based on the DCI format for scheduling the PDSCH for URLLC and the DCI format for scheduling the PDSCH for eMBB. For example, DCI format 0_0 or DCI format 1_0 always schedules a PUSCH or PDSCH with low priority. DCI format 0_1 ​​or DCI format 1_1 always schedules a PUSCH or PDSCH with low priority. DCI format 0_2 or DCI format 1_2 always schedules a PUSCH or PDSCH with high priority.

[0142] Based on this method, the terminal knows the priority of each PDSCH transmitted from the base station, and generates a HARQ-ACK codebook by collecting HARQ-ACKs of PDSCHs corresponding to the same priority. Hereinafter, the HARQ-ACK codebook described in the present invention means a HARQ-ACK codebook for HARQ-ACKs of PDSCHs corresponding to the same priority unless otherwise specified.

[0143] FIG. 14 is a diagram illustrating an example of a method for transmitting HARQ-ACK based on downlink control information having different formats according to an embodiment of the present invention.

[0144] The DAI received from the PDCCH (or DCI) is divided into counter-DAI and total-DAI, and counter-DAI and total-DAI are each set to a maximum of 2 bits. However, in DCI format 1_0, the number of counter-DAI bits is fixed at 2 bits, and in DCI format 1_1, the number of counter-DAI bits is fixed at 2 bits and the number of total-DAI bits is fixed at 2 bits.

[0145] The length of each DCI field in DCI format 1_2 and DCI format 0_2 is configured in the terminal by the base station. For example, in DCI format 1_2, the base station configures the length of the DAI field for generating the HARQ-ACK codebook. In DCI format 1_2, the length of the DAI field is configured to one of 0 bits, 1 bit, 2 bits, or 4 bits. If the length of the DAI field is configured to 1 bit or 2 bits, counter-DAI is 1 bit or 2 bits, and total-DAI is 0 bit. If the length of the DAI field is configured to 4 bits, counter-DAI is 2 bits, and total-DAI is 2 bits.

[0146] 14, a PDSCH corresponding to one HARQ-ACK codebook of one terminal is scheduled by DCI format 1_0, DCI format 1_1, or DCI format 1_2. In other words, the DCI formats of the PDSCH corresponding to one HARQ-ACK codebook have counter-DAI bit-sizes of different lengths. Hereinafter, a method for generating an HARQ-ACK codebook when the DCI formats have counter-DAI bit-sizes of different lengths will be examined.

[0147] FIG. 15 is a diagram illustrating another example of a method for transmitting HARQ-ACK based on downlink control information having different formats according to an embodiment of the present invention.

[0148] Referring to FIG. 15, a terminal generates a HARQ-ACK codebook for a PDSCH scheduled by each PDCCH having a different DCI format and transmits the codebook to a base station.

[0149] Specifically, as described above, when the DCI formats are different, the number of bits of the DAI field included in each DCI may also be different. In this case, the terminal generates a HARQ-ACK codebook including HARQ-ACK bits of PDSCHs scheduled by PDCCHs (or DCIs) with DAI fields having different numbers of bits, and transmits the HARQ-ACK codebook to the base station.

[0150] In this case, it is difficult for the terminal to count the received DAIs because the bit numbers of the DAI fields are different. That is, if the bit value of the DAI field of the first PDCCH (or DCI) is '0' and the bit value of the DAI field of the second DCI is '11', it is difficult for the terminal to determine whether the two received PDSCHs are transmitted consecutively.

[0151] Therefore, if the number of counter-DAI bits for each received PDCCH (or DCI) is different, the terminal adjusts the number of counter-DAI bits to match the number of counter-DAI bits and determines which PDSCH the received PDSCH is. That is, the terminal adjusts the number of bits by recognizing only some of the counter-DAI bits with a larger number of bits as valid bits, or by extending and interpreting the counter-DAI bits with a smaller number of bits.

[0152] Proposal 1: Only some of the bits in counter-DAI are recognized as valid bits to generate a HARQ-ACK codebook.

[0153] If the number of bits in the counter-DAI field of the DCI formats monitored by the terminal is different, the terminal recognizes only some of the bits in the counter-DAI field with a larger number of bits as valid bits to generate a HARQ-ACK codebook. In this case, the number of valid bits is the same as the number of bits in the DAI field with a smaller number of bits among the DAI fields of the received PDCCH (or DCI). In addition, since the number of bits in the counter-DAI field is fixed to 2 bits in DCI format 1_0 and DCI format 1_1, and the number of bits in the counter-DAI field in DCI format 1_2 can be set to 0, 1, or 2 bits, the DAI field with a smaller number of bits among the DAI fields is the same as the number of bits in the counter-DAI included in DCI format 1_2. In other words, if the terminal is configured to monitor DCI format 1_2, it recognizes the number of bits of counter-DAI in DCI format 1_2 as the number of valid bits, and recognizes only the valid number of bits of the 2-bit counter-DAI in DCI format 1_0 or DCI format 1_1 as the valid bits for counter-DAI.

[0154] For details, the bit size of counter-DAI in DCI format 1_2 is NC-DAI If set to bit, N of the 2 bits in the counter-DAI field of other DCI formats, DCI format 1_0 and DCI format 1_1, is used. C-DAI Only bit(s) is considered valid. In this case, the bit considered valid is LSB N C-DAI bit(s) or MSB N C-DAI bit(s).

[0155] And N C-DAI The value of bit(s) determines the counter-DAI value. For example, N C-DAI If the value is "1", the number of valid bits is 1. In this case, if the binary value of the valid bit is 0, the counter-DAI value is 1, and if the binary value of the valid bit is 1, the counter-DAI value is 2.

[0156] N C-DAI If the value is "2", the number of valid bits is 2 bits. In this case, if the binary value of the valid bit is 00, the counter-DAI value is 1, and if the binary value is 01, the counter-DAI value is 2. Also, if the binary value is 10, the counter-DAI value is 3, and if the binary value is 11, the counter-DAI value is 4.

[0157] For example, as shown in Figure 15(a), the bit-size of counter-DAI in DCI format 1_2 is N C-DAI If is set to 1 bit, the terminal recognizes only the LSB or MSB 1 bit of the 2-bit counter-DAI of DCI format 1_0 and DCI format 1_1 as the valid counter-DAI bit number.

[0158] In other words, the number of bits in the counter-DAI field of the received DCI that has the smallest number of bits is determined to be the number of valid bits, and only some of the LSBs or MSBs of the remaining number of bits in the counter-DAI field of the DCI are recognized as valid, and the number of bits in the counter-DAI of the received DCI is adjusted to the same number.

[0159] The terminal selects a valid N from the counter-DAI field of each DCI format. C-DAI For example, Figure 15(a) shows the effective bit-size of counter-DAI for DCI format 1_2, N C-DAI This shows the binary value for counter-DAI when the value is set to 1 bit.

[0160] As shown in Figure 15(a), counter-DAI in DCI format 1_1 has two bits with binary values ​​of 00, 01, 10, and 11, but only the LSB bit is valid. Invalid binary values ​​are indicated by x. At the same monitoring opportunity, the counter-DAI value increases by one in ascending order of cell index.

[0161] In detail, the counter-DAI value is determined by the number of PDCCHs transmitted up to the current cell in the current monitoring opportunity. If X PDCCHs have been transmitted up to now, the counter-DAI value is (X-1 mod 2^N C-DAI The counter-DAI value is determined as .DELTA..times ...

[0162] If the format of the received DCI is DCI format 1_1 and the format of the subsequently received DCI is DCI format 1_1, the valid bit of counter-DAI is set to 1. In this case, only the MSB or LSB of the counter-DAI field of DCI format 1_1 is recognized as a valid bit, and the invalid counter-DAI bits are not used to calculate the counter-DAI value.

[0163] For example, as shown in Figure 15(a), the number of bits of counter-DAI in the received DCI format 1_2 is N C-DAI is 1 bit, the terminal determines the number of valid bits to be 1 bit, and even if the number of bits of counter-DAI in DCI format 1_1 is set to 2 bits, only the MSB or LSB of the 2 bits is used to determine the counter-DAI value. Therefore, the 1 bit that is not valid, indicated as "x" in Figure 15(a), is not used to determine the counter-DAI value.

[0164] If the counter-DAI bit of DCI format 1_2 is "0", the counter-DAI value is determined to be 1. In this case, if the two bits of counter-DAI of the next transmitted DCI format 1_1 are "11" or "01", the terminal determines the counter-DAI value using only the LSB value "1", which is the valid bit. Therefore, the counter-DAI value of DCI format 1_1 is recognized as 2.

[0165] Furthermore, Proposal 1 is interpreted as follows: if the 2-bit counter-DAI bits of DCI format 1_0 or DCI format 1_1 are "00", the terminal determines the counter-DAI value to be 1, if "01", the counter-DAI value to be 2, if "10", the counter-DAI value to be 3, and if "11", the counter-DAI value to be 4.

[0166] If the UE sets the number of bits of counter-DAI of DCI format 1_2 to 1, the UE determines the counter-DAI value to be 1 or 2. Here, if the 2-bit counter-DAI value is C2, C2 has one of the values ​​1, 2, 3, and 4. If the 1-bit counter-DAI value is C1, C1 has one of the values ​​1 and 2.

[0167] In this case, the 2-bit counter-DAI value C2 is converted to the same bit value as the 1-bit counter-DAI value C1 by C1 = (C2 - 1) mod 2 + 1. This method has the same effect as determining the LSB 1 bit as valid in Proposal 1 and interpreting the 1 LSB as a 1-bit 2-bit counter-DAI value.

[0168] If the counter-DAI value of the previously received PDCCH (or DCI) is 1 and the counter-DAI value of the later received PDCCH (or DCI) is 1, the terminal recognizes that the two PDCCHs were not transmitted consecutively and that at least one PDCCH was transmitted between the two PDCCHs but was not received by the terminal.

[0169] However, if the terminal fails to receive two consecutive PDCCHs, it cannot recognize this. C-DAI If is set to 1 bit, a maximum of one PDCCH reception failure can be detected, but two or more consecutive PDCCH reception failures cannot be detected.

[0170] As mentioned above, counter-DAI is fixed to 2 bits in DCI formats 1_0 and 1_1. Therefore, in DCI formats 1_0 and 1_1, counter-DAI with 2 bits can detect up to three consecutive PDCCH reception failures. However, Proposal 1 sets the effective bit count to 1 bit, which is the counter-DAI bit count in DCI format 1_2, which may degrade the detection performance of PDCCH reception failures.

[0171] Proposal 2: Generate a HARQ-ACK codebook based on the largest number of bits among the counter-DAI bits.

[0172] In the case of Proposal 1, as described above, the number of valid bits of counter-DAI is only one, so it is not possible to recognize that two or more consecutive PDCCHs have not been detected, making it difficult to detect a failure to receive a PDCCH.

[0173] To solve this problem, when the number of bits of counter-DAI differs depending on the format, the number of bits of counter-DAI is extended based on the number of bits of counter-DAI, and the counter-DAI value is determined.

[0174] For details, the bit size of counter-DAI in DCI format 1_2 is N C-DAI If bit is set to N C-DAI The 1-bit counter-DAI is interpreted as a 2-bit counter-DAI value, and the 2-bit counter-DAI for DCI format 1_0 and DCI format 1_1 is determined to be valid.

[0175] For example, as shown in Figure 15(b), DCI format 1_0 and DCI format 1_1 include a 2-bit counter-DAI, so if the counter-DAI bits are "00" in binary, the counter-DAI value is 1, and if they are "01" in binary, the counter-DAI value is 2. Also, if the counter-DAI bits are 10 in binary, the counter-DAI value is 3, and if they are 11 in binary, the counter-DAI value is 4.

[0176] In this case, the bit size of counter-DAI in DCI format 1_2 is N C-DAI If the value is 1 bit, the number of bits in counter-DAI of DCI format 1_2 is extended to 2 bits and interpreted as such. For example, if 1 bit of counter-DAI of DCI format 1_2 is "0", if this is extended to 2 bits, counter-DAI will have a bit value of "00" or "10". Therefore, the counter-DAI value will be extended to 1 or 3.

[0177] Alternatively, if one bit of counter-DAI in DCI format 1_2 is "1," and this is extended to two bits, counter-DAI has a bit value of "01" or "11." Therefore, the counter-DAI value is extended to 2 or 4.

[0178] When counter-DAI, which has a size of 1 bit in DCI format 1_2, is extended to 2 bits according to Proposal 2, the counter-DAI value has two or more candidate values ​​due to the extended interpretation. In this case, the UE recognizes the value with the smallest number of non-consecutive PDCCHs as the counter-DAI value. That is, when the number of bits of counter-DAI is extended and interpreted, the UE determines the counter-DAI value with the smallest number of undetected PDCCHs.

[0179] For example, if the 2-bit counter-DAI value of the previously received DCI is 3 and the 1-bit counter-DAI bit of the later received PDCCH (or DCI) is '1', the UE extends the 1-bit counter-DAI to 2 bits and determines the value 4, which is the value with the least number of undetected PDCCHs, from among the possible counter-DAI values ​​2 and 4. In other words, if the counter-DAI of the later received PDCCH (or DCI) is determined to be 2, it is determined that the reception of two PDCCHs (or DCIs) with counter-DAI values ​​of 4 and 1 has failed. However, if the counter-DAI of the later received PDCCH (or DCI) is determined to be 4, the UE determines that there is no PDCCH (or DCI) that has failed to be received. If the probability that a terminal fails to receive a PDCCH is p, then the probability that the terminal fails to receive two consecutive PDCCHs (or DCIs) when counter-DAI is set to 2 is p. 2 The probability that the counter-DAI is 4 and there is no failure in receiving the PDCCH (or DCI) is 1-p. Generally, the base station determines that the terminal will successfully receive the PDCCH (or DCI) so that p is a very small value. Therefore, the counter-DAI 4 with a probability of 1-p is p 2 Therefore, in the above case, it is preferable to determine counter-DAI as 4 since the probability of counter-DAI being 4 is higher than that of counter-DAI being 2.

[0180] Table 7 below shows an example of an extended counter-DAI value for the counter-DAI of a previously received DCI when the counter-DAI bits are extended and interpreted. Here, counter-DAI is 1 bit, and the counter-DAI value of the previously received DCI is 2 bits. [Table 7]

[0181] In Table 7, the numbers in parentheses represent the respective bit values.

[0182] As another example of Proposal 2, DCI format 1_0 and DCI format 1_1 include a 2-bit counter-DAI, so if the counter-DAI bits are "00" in binary, the counter-DAI value is 1, and if they are "01" in binary, the counter-DAI value is 2. Also, if the counter-DAI bits are 10 in binary, the counter-DAI value is 3, and if they are 11 in binary, the counter-DAI value is 4.

[0183] In this case, the bit size of counter-DAI in DCI format 1_2 is N C-DAI If the value is 0 bits, the number of bits in counter-DAI of DCI format 1_2 is extended to 2 bits and interpreted as such. In this case, since the size of counter-DAI is 0 bits, if this is extended to 2 bits, the 0-bit counter-DAI has four candidate values.

[0184] When the terminal extends the counter-DAI value to the value that minimizes the number of undetected PDCCHs among the four candidate values, it determines the counter-DAI value as a value consecutive to the counter-DAI value of the previously received DCI.

[0185] Table 8 below shows an example of an extended counter-DAI value for the counter-DAI of a previously received DCI when the counter-DAI bits are extended and interpreted. Here, counter-DAI is 0 bits and the counter-DAI value of the previously received DCI is 2 bits. [Table 8]

[0186] That is, if the bit size of counter-DAI in DCI format 1_2 is smaller than 2 bits, there are multiple possible 2-bit counter-DAI values, and the terminal selects one of the multiple possible 2-bit counter-DAI values.

[0187] To select one of the multiple candidate values, the following specific method is used.

[0188] Let the counter-DAI value of the most recently received PDCCH be C, and when interpreting the counter-DAI of the currently received DCI format 1_2 as 2 bits, the possible 2-bit counter-DAI values ​​are assumed to be i1, i2, .... The UE should determine one of the values ​​i1, i2, ... as the 2-bit counter-DAI value using the value of C.

[0189] The terminal calculates the Y value based on the following equation 2 in the order of x=1, 2, 3, ... [Formula 2] Y=((V temp or C)+x-1 mod 4)+1

[0190] If Y is one of the values ​​i1, i2, ..., the UE determines the 2-bit counter-DAI value to be Y. This is a method for setting the 2-bit counter-DAI value so that the number of PDCCHs that fail to be received during the currently received DCI format 1_2 after the previously received PDCCH is minimized.

[0191] In Tables 4 and 5, V temp is the counter-DAI value with a 2-bit size of the previous one (i.e., the cell with a lower cell index in the current monitoring occasion, or the PDCCH last received in the previous monitoring occasion) (if the last received DCI format was DCI format 1_2, it is interpreted as a 2-bit counter-DAI value).

[0192] For example, V tempIf the value of counter-DAI is 1 and the counter-DAI of the currently received DCI format 1_2 is binary 0, the counter-DAI has a value of 1 or 3. If it is determined to be 3, it means that one PDCCH (counter-DAI value 2) was transmitted between the previously received PDCCH (counter-DAI value 1) and the currently received PDCCH (counter-DAI value 3) but its reception was unsuccessful. If it is determined to be 1, it means that three PDCCHs (counter-DAI values ​​2, 3, 4) were transmitted between the previously received PDCCH (counter-DAI value 1) and the currently received PDCCH (counter-DAI value 1) but their reception was unsuccessful. According to the above embodiment, it is assumed that the fewest number of PDCCHs were transmitted but their reception was unsuccessful, and the counter-DAI value of the currently received PDCCH is determined to be 3.

[0193] In Proposals 1 and 2, only the counter-DAI is used to generate the HARQ-ACK codebook, but the total-DAI value may also be used to generate the HARQ-ACK codebook. For example, in DCI format 1_2, the total-DAI is N. T-DAI In this case, similar to the method in Proposal 1, the LSB (or MSB) N of the 2-bit total-DAI field of DCI format 1_1, which includes a 2-bit total-DAI field, is set. T-DAI Only the valid bits are determined, and the valid N T-DAI Determine the total-DAI value based on the bits.

[0194] In another embodiment of the present invention, a HARQ-ACK codebook is generated using a 2-bit total-DAI value. The total-DAI value is determined by the number of PDCCHs received up to the current monitoring opportunity. If the number of PDCCHs received up to the current monitoring opportunity is T, then N T-DAI The total DAI in bits is ((T-1) mod 2^N T-DAI ) + 1. The PDCCH received in one monitoring opportunity has the same 2-bit total-DAI value.

[0195] In another embodiment of the present invention, if at least one DCI format 1_1 is received in one monitoring occasion, the 2-bit total-DAI value included in DCI format 1_1 is used. That is, if a DCI format including a 2-bit total-DAI and a DCI format including a 1-bit total-DAI or a 0-bit total-DAI are received in the same monitoring occasion, the 2-bit total-DAI value is assumed because it contains the most information.

[0196] In yet another embodiment of the present invention, if DCI format 1_1 cannot be received in one monitoring opportunity but DCI format 1_2 is received, the 2-bit total-DAI value is determined as follows:

[0197] N, the bit size of total-DAI in DCI format 1_2 T-DAI If the value of is 1 bit, it is expanded to a 2-bit total-DAI value and interpreted as such. For example, if the bit of the 1-bit total-DAI is "0", the total-DAI value is 1 or 3, and if it is "1", the total-DAI value is 2 or 4.

[0198] N, the bit size of total-DAI in DCI format 1_2 T-DAI If the value of is 0-bit (i.e., total-DAI is not included in the DCI format), the 0-bit total-DAI is interpreted as a 2-bit total-DAI value.

[0199] For example, a 0-bit total-DAI value can be 1, 2, 3, or 4. That is, if the total-DAI bit size of DCI format 1_2 is smaller than 2 bits, the 2-bit total-DAI has multiple candidate values. In this case, one value is selected from the multiple candidate values ​​using the following method.

[0200] The 2-bit counter-DAI value of the PDCCH received at the end of the current monitoring opportunity (i.e., received at the cell with the highest cell index) is C, and the 2-bit total-DAI values ​​that the total-DAI included in the DCI of the PDCCH received at the corresponding monitoring opportunity may have are j1, j2, ...

[0201] In this case, the terminal should determine one of j1, j2, ... as the 2-bit total-DAI value using the C value. The terminal calculates the Z value according to the following Equation 3 in order according to the x (x = 0, 1, 2, 3, ...) value. [Formula 3] Z=((V temp2 or C)+x-1 mod 4)+1

[0202] If Z is one of j1, j2, ..., the UE determines the 2-bit total-DAI value to be Z. This is a method of setting the 2-bit total-DAI value so as to minimize the number of PDCCHs that fail to receive the PDCCHs transmitted after the last PDCCH of the current monitoring occasion.

[0203] Table 9 below shows an example of a total-DAI value selected from a plurality of candidate values. [Table 9]

[0204] In Table 9, V temp2 is the 2-bit counter-DAI value of the last PDCCH received at the end of the monitoring opportunity. For example, temp2 If the value of total-DAI is 2 and the received DCI format 1_2 total-DAI is binary 0, total-DAI has a value of 1 or 3.

[0205] If the total-DAI value is determined to be 3, this means that one PDCCH (counter-DAI value is 3) has been transmitted after the last received PDCCH (counter-DAI value is 2), but the terminal has not detected this. If the total-DAI value is determined to be 1, this means that three PDCCHs (counter-DAI values ​​are 3, 4, and 1) have been transmitted after the last received PDCCH (counter-DAI value is 2), but the terminal has not detected this. In the above-mentioned embodiment, it is assumed that the smallest number of PDCCHs have been transmitted but have not been received successfully, and the total-DAI value of the received PDCCH is determined to be 3.

[0206] In this manner, even if the number of bits of counter-DAI or total-DAI of DCIs having different formats is different, the terminal determines the number of valid bits or interprets the number of bits in an extended manner, and multiplexes HARQ-ACK codebooks for PDSCHs scheduled by multiple DCIs and transmits them to the base station.

[0207] FIG. 16 illustrates an example of a method for transmitting HARQ-ACK based on downlink control information for uplink and downlink scheduling according to an embodiment of the present invention.

[0208] Referring to FIG. 16, the UE multiplexes a HARQ-ACK codebook including HARQ-ACK bits of the PDSCH scheduled via the DCI of the PDCCH and a PUSCH scheduled via the DCI, and transmits the multiplexed codebook to the base station.

[0209] Specifically, as shown in FIG. 16, the UE multiplexes (or piggybacks) the HARQ-ACK bit of the received PDSCH onto the PUSCH and transmits it to the base station. In this case, the DCI format for scheduling the PDSCH is DCI format 1_0, DCI format 1_1, and / or DCI format 1_2. In addition, the DCI format for scheduling the PUSCH onto which the HARQ-ACK bit is multiplexed (or piggybacked) is DCI format 0_0, DCI format 0_1, and / or DCI format 0_2, etc.

[0210] The length of the UL DAI field included in DCI format 0_2 is set to 0, 1, or 2 bits, and the length of the counter DAI field included in DCI format 1_2 is set to 0, 1, or 2 bits.

[0211] In addition, DCI format 0_0 and DCI format 0_1 ​​include a 2-bit UL DAI field, and DCI format 1_0 and DCI format 1_1 include a 2-bit counter-DAI field.

[0212] In this case, if the length of the UL DAI field is not the same as the length of the counter-DAI field of DCI format 1_2, the UL DAI field value must be determined based on the counter-DAI field. In the following embodiments, it is assumed that the length of the DAI field is at least 0. In other words, the DCI format includes a DAI field whose length is at least 1 bit.

[0213] As a first embodiment, if the length of the UL DAI field is greater than the length of the counter-DAI field in DCI format 1_2 (for example, if the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the terminal determines that only some bits in the UL DAI field are valid bits of the UL DAI field. Here, the number of bits of some bits is the same as the number of bits of the counter-DAI field, and they are the bits closest to the MSB or LSB of the UL DAI field.

[0214] The terminal calculates the UL DAI value using the bits determined to be valid bits among the bits of the UL DAI field. If the valid bit of the UL DAI field is 1 bit, if the 1 bit is "0", the UL DAI value is 1, and if it is 1, the UL DAI value is 2.

[0215] If the valid bits of the UL DAI field are 2 bits, if the 2 bits are 00, the UL DAI value is 1, if it is 01, the UL DAI value is 2. Also, if the 2 bits are 10, the UL DAI value is 3, and if it is 11, the UL DAI value is 4.

[0216] The terminal uses the UL DAI value obtained using the bits of the UL DAI field determined to be valid and the counter-DAI value obtained from the counter-DAI field to determine the number of HARQ-ACK bits for the PDSCHs that could not be received.

[0217] For example, let the UL DAI value be X and the counter-DAI value be Y. If X = Y, it is determined that there is no PDSCH that could not be received. However, if Y < X, it is determined that X - Y PDSCHs could not be received, and if X < Y, it is determined that T - (Y - X) PDSCHs could not be received. Here, T = 2 N where N is the number of bits of the counter-DAI field.

[0218] In a second embodiment, if the length of the UL DAI field is greater than the length of the counter-DAI field of DCI format 1_2 (for example, if the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the terminal first determines the UL DAI value based on the length of the UL DAI field, and then modifies the determined UL DAI value based on the counter-DAI field to determine the final UL DAI value.

[0219] The process of determining the UL DAI value based on the length of the UL DAI field is as follows: If the length of the UL DAI field is 1 bit, if the bit value is '0' the UL DAI value is 1, and if the bit value is '1' the UL DAI value is 2.

[0220] If the UL DAI field is 2 bits long, a bit value of "00" means the UL DAI value is 1, a bit value of "01" means the UL DAI value is 2, a bit value of "10" means the UL DAI value is 3, and a bit value of "11" means the UL DAI value is 4.

[0221] Once the UL DAI value is determined by the UL DAI field, the terminal modifies the determined UL DAI value according to the counter-DAI field to determine the final UL DAI value as follows:

[0222] N is the number of bits in the counter-DAI field, and T=2 N If the determined UL DAI value is Z, the final UL DAI value (X) is calculated using Equation 4 below. [Formula 4] Final UL DAI value (X) = ((Z-1) mod T) + 1

[0223] The terminal determines the number of HARQ-ACK bits for the PDSCHs that could not be received, using the final UL DAI value (X) and the counter-DAI value obtained from the counter-DAI field. For example, if the counter-DAI value is Y, when X = Y, it is determined that there is no PDSCH that could not be received. However, when Y < X, it is determined that X - Y PDSCHs could not be received, and when X < Y, it is determined that T - (Y - X) PDSCHs could not be received. Here, T = 2 N where N is the number of bits of the counter-DAI field.

[0224] As a third embodiment, if the length of the UL DAI field is greater than the length of the counter-DAI field of DCI format 1_2 (for example, if the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the terminal assumes (or recognizes) that the range of the UL DAI field value is the same as the range of values that the counter-DAI can indicate. For example, if the values that the counter-DAI can indicate are 1, 2, 3, 4, the UL DAI value is recognized as one of the values 1, 2, 3, 4.

[0225] )Specifically, the terminal determines the UL DAI value according to the length of the UL DAI field. If the length of the UL DAI field is 1 bit and the bit value is "0", the UL DAI value is 1, and if it is 1, the UL DAI value is 2. If the UL DAI field is 2 bits, when the bit value is "00", the UL DAI value is 1, and if it is 01, the UL DAI value is 2. Also, if the 2-bit value is "10", the UL DAI value is 3, and if it is "11", the UL DAI value is 4.

[0226] The UL DAI value should always be within the range of values ​​that counter-DAI can indicate. For example, if the length of the UL DAI field is 2 bits, the range of UL DAI values ​​is 1, 2, 3, and 4. If the range of values ​​that counter-DAI can have is 1 and 2, the length of the UL DAI field is 2 bits, but the possible UL DAI values ​​are 1 and 2.

[0227] In other words, the terminal does not expect to be specified a UL DAI value that indicates a value outside the range of values ​​that counter-DAI can have, nor does it expect to be specified a UL DAI value of 10 or 11, which indicates 3 or 4. In other words, if such a value is specified, the terminal will determine it as an error case.

[0228] As described above, the length of the UL DAI field included in DCI format 0_2 is set to 0, 1, or 2 bits. If the length of such a UL DAI field is less than 2 bits, the UL DAI is determined as a 2-bit UL DAI value in the same manner as the 2-bit total-DAI value is determined.

[0229] That is, the UL DAI value is determined using the last received 2-bit counter-DAI value. Table 10 below shows an example of a 2-bit UL DAI value. [Table 10]

[0230] In Table 10, V temp3 is the 2-bit counter-DAI value of the last PDCCH among the received PDCCHs. For example, the previous V temp3 If the value of UL DAI is 2 and the bit value of UL DAI of received DCI format 0_2 is "0", then UL DAI has a value of 1 or 3.

[0231] If the UL DAI value is determined to be 3, it means that one PDCCH (counter-DAI value 3) was transmitted but failed to be received after the last received PDCCH (counter-DAI value 2), and if the UL DAI value is determined to be 1, it means that three PDCCHs (counter-DAI values ​​3, 4, and 1) were transmitted but failed to be received after the last received PDCCH (counter-DAI value 2). As mentioned above, if it is assumed that the fewest number of PDCCHs were transmitted but failed to be received, the 2-bit UL DAI value is determined to be 3.

[0232] FIG. 17 is a diagram illustrating an example of a downlink allocation indicator of each piece of downlink control information detected from a monitoring occasion according to an embodiment of the present invention.

[0233] In another embodiment of the present invention, if the bit size of the UL DAI field of DCI format 0_0, 0_1, or 0_2 is different from the bit size of the counter-DAI field of DCI format 1_0, 1_1, or DCI format 1_2, the terminal performs the following operation.

[0234] The bit size of the counter-DAI field in DCI format 1_0, 1_1, or 1_2 is N C-DAI bits, counter-DAI values ​​are 1, 2, ..., 2^N C-DAI where the largest value C D is 2^N C-DAI , that is, the bit size of the counter-DAI field is N C-DAI If the counter-DAI field has 2 bits, the bit value of the counter-DAI field is 1 if it is "00", 2 if it is "01", 3 if it is "10", and 4 if it is "11". D The value of is 4.

[0235] Or, N C-DAI If the counter-DAI field is 1 bit, the bit value is 1 if it is "0" and 2 if it is "1".D The value of is 2.

[0236] If the UE receives a DCI format for scheduling a PDSCH in serving cell c on monitoring occasion m, and the counter-DAI value of the received DCI format is V C-DAI、c、m If so, the UE assigns the DCI format for scheduling the PDSCH to the current serving cell c of the current monitoring opportunity m in which the DCI format is received as C D *j+V C-DAI、c、m It is determined that j is received, where j is a non-negative integer.

[0237] In other words, if the number of DCI formats for scheduling PDSCH to the current serving cell c of the current monitoring opportunity m in which the DCI format is received is X, the counter-DAI value of that DCI format is V. C-DAI、c、m =(X-1 mod C D )+1.

[0238] The bit size of the UL DAI field in DCI format 0_0, 0_1, or 0_2 is N UL-DAI bits, UL DAI values ​​are 1, 2, …, 2^N UL-DAI where the largest value U D is 2^N UL-DAI That is, the bit size of the UL DAI field is N UL-DAI is 2 bits, the bit value of the UL DAI field is 1 if it is "00", 2 if it is "01", 3 if it is "10", and 4 if it is "11". D The value of is 4.

[0239] If the UE receives a DCI format for scheduling a PUSCH at monitoring opportunity m, and the UL-DAI value of the received DCI format is V UL-DAI、m If so, the UE assigns the DCI format for scheduling the PDSCH up to the current monitoring opportunity m in which the DCI format is received as UD *i+V UL-DAI、m It is determined that the number of received packets is 1, where i is a non-negative integer.

[0240] In other words, if the number of DCI formats for scheduling PDSCH up to the current monitoring opportunity m in which the DCI format is received is X, the UL-DAI value of that DCI format is V UL-DAI、m =(X-1 mod U D )+1.

[0241] For example, U D The value of is 4, and C D If the value is 2, the counter-DAI value will be 1 or 2, and the UL-DAI value will be 1, 2, 3, or 4. Figure 17(a) shows an example of counter-DAI values ​​in the DCI format received at monitoring occasions (MOs) #0 to #6.

[0242] According to the definition of the counter-DAI value, the counter-DAI value of the DCI format received from MO#0 is 1, the counter-DAI value of the DCI format received from MO#1 is 2, the counter-DAI value of the DCI format received from MO#2 is 1, the counter-DAI value of the DCI format received from MO#3 is 2, the counter-DAI value of the DCI format received from MO#4 is 1, the counter-DAI value of the DCI format received from MO#5 is 2, and the counter-DAI value of the DCI format received from MO#6 is 1. The terminal then receives a DCI format for scheduling a PUSCH. The UL DAI value of the received DCI format is 3. This is because seven DCI formats for scheduling a PDSCH have been received first.

[0243] This invention proposes a method for the terminal to generate a HARQ-ACK codebook when the bit size of the counter DAI and the bit size of the UL DAI are different. In Figure 17(b), assume that the terminal failed to receive the DCI formats of MO#4 and MO#5. Since the terminal received the DCI format with a counter-DAI value of 2 in MO#3 and the DCI format with a counter-DAI value of 1 in MO#6, the terminal cannot know that it failed to receive the DCI formats of MO#4 and MO#5. Therefore, the terminal generates only HARQ-ACK bits for the DCI formats received in MO#0, MO#1, MO#2, MO#3, and MO#6 and includes them in the HARQ-ACK codebook.

[0244] If the UE receives a UL-DAI value of 3 in the DCI format for scheduling the PUSCH, the UE recognizes that there are two more DCI formats in addition to the five successfully received DCI formats, and therefore the UE generates HARQ-ACK bits for a total of seven DCI formats and includes them in the HARQ-ACK codebook.

[0245] FIG. 19 illustrates an example of a method for transmitting HARQ-ACK based on downlink control information having different formats, based on pseudocode according to an embodiment of the present invention.

[0246] Referring to Figure 19, a HARQ-ACK codebook is generated using the UL-DAI value and counter-DAI value using pseudocode and transmitted to the base station. Figure 19 shows an example of multiplexing a 2-bit UL-DAI and a 1-bit counter-DAI.

[0247] Specifically, in one embodiment of the present invention, the UL-DAI value and the counter-DAI value are used as follows: First, as shown in FIG. 19(a), the terminal sets the counter-DAI value received from the most recent MO to V tempAs mentioned above, the counter-DAI value is 1, 2, ..., C D The UL DAI value received by the UE in the DCI format for scheduling the PUSCH is V temp2 The terminal generates the HARQ-ACK codebook in the following manner.

[0248] First, the device is V temp The number of DCI formats for which PDSCH is scheduled is W temp Determine W temp is determined by the following equation 5. [Formula 5] W temp =C D *j+V temp

[0249] In Equation 5, the initial j value is set to 0, and if the counter-DAI value of the DCI format for scheduling the PDSCH in the current MO is smaller than the counter-DAI value of the DCI format for scheduling the PDSCH in the previous MO, it is incremented by 1. That is, if the counter-DAI value is 1, 2, ..., C D DCI formats are grouped into one group, and j indicates the number of groups received. In Figure 17(b), j=2.

[0250] Next, the terminal determines the number of DCI formats for which PDSCH is scheduled (W temp ) as shown in Figure 19(b), which is the bit size of the UL DAI field, N UL-DAI V' is the counter-DAI value corresponding to temp where V' temp is determined by the following equation 6. [Formula 6] V' temp =((W temp -1)mod U D )+1

[0251] In Equation 6, V'temp Like UL DAI, 1, 2, …, U D The terminal has one of the values ​​V' temp and V temp2 Compare and determine the j value. If V temp2 <V’ temp If so, the j value is determined by the following equation 7.

number

[0252] Otherwise, j is left as it is. Using the j value, the terminal calculates the size of the HARQ-ACK codebook, O ACK If the terminal is configured to receive only 1 TB per PDSCH, then O ACK is calculated by the following formula 8.

number

[0253] If the terminal is configured to receive 2TB per PDSCH, then ACK is calculated by the following formula 9.

number

[0254] This is expressed in pseudocode as shown in Table 11 below. [Table 11-1] [Table 11-2] [Table 11-3]

[0255] FIG. 18 is a diagram illustrating another example of a downlink allocation indicator in each piece of downlink control information detected from a monitoring opportunity according to an embodiment of the present invention.

[0256] In another embodiment of the present invention, when the bit size of the total DAI field of DCI format 1_0, 1_1, or 1_2 is different from the bit size of the counter-DAI field of DCI format 1_0, 1_1, or DCI format 1_2, the terminal generates a HARQ-ACK codebook by the following operation.

[0257] The bit size of the counter-DAI field in DCI format 1_0, 1_1, or 1_2 is N C-DAI bits, counter-DAI values ​​are 1, 2, ..., 2^N C-DAI where the largest value C D is 2^N C-DAI , that is, the bit size of the counter-DAI field is N C-DAI If the counter-DAI field has 2 bits, the bit value of the counter-DAI field is 1 if it is "00", 2 if it is "01", 3 if it is "10", and 4 if it is "11". D The value of is 4.

[0258] Or, N C-DAI If the counter-DAI field has 1 bit, the bit value is 1 if it is 0, and 2 if it is 1. D The value of is 2.

[0259] If the terminal receives a DCI format for scheduling PDSCH in serving cell c on monitoring occasion m, and the counter-DAI value of the received DCI format is V C-DAI、c、m If so, the UE assigns the DCI format for scheduling the PDSCH to the current serving cell c of the current monitoring opportunity m in which the DCI format is received as C D *j+V C-DAI、c、m It is determined that j is received, where j is a non-negative integer.

[0260] In other words, if the number of DCI formats for scheduling PDSCH up to the current serving cell c of the current monitoring opportunity m in which the DCI format is received is X, then the counter-DAI value V of that DCI format is C-DAI、c、m =(X-1 mod C D )+1.

[0261] The bit size of the total DAI field in DCI format 1_0, 1_1, or 1_2 is N T-DAI If bits, the total-DAI value is 1, 2, ..., 2^N T-DAI where the largest value T D is 2^N T-DAI That is, the bit size of the total DAI field is N T-DAI is 2 bits, the bit value of the total DAI field is 1 if it is 00, 2 if it is 01, 3 if it is 10, and 4 if it is 11. D The value of is 4.

[0262] If the UE receives a DCI format for scheduling a PUSCH at monitoring opportunity m, and the total DAI value of the received DCI format is V T-DAI、m If so, the UE sets the DCI format for scheduling the PDSCH up to the current monitoring opportunity m in which the DCI format is received as T D *i+V T-DAI、m It is determined that i has been received, where i is a non-negative integer.

[0263] In other words, if the number of DCI formats for scheduling PDSCH up to the current monitoring opportunity m in which the DCI format is received is X, the total DAI value of that DCI format is V T-DAI、c、m =(X-1 mod T D )+1.

[0264] T D The value of is 4, and C DLet us take the case where the value of is 2 as an example. The counter-DAI value of the terminal is set to 1 or 2, and the total-DAI has a value of 1, 2, 3, or 4.

[0265] FIG. 18(a) shows the (counter-DAI, total-DAI values) of the DCI format received by MOs #0 to #6. According to the definition of the counter-DAI value and total DAI value, the (counter-DAI, total-DAI) of the DCI format received from MO#0 is (1,1), the (counter-DAI, total-DAI) of the DCI format received from M1#0 is (2,2), the (counter-DAI, total-DAI) of the DCI format received from MO#2 is (1,3), the (counter-DAI, total-DAI) of the DCI format received from MO#3 is (2,4), the (counter-DAI, total-DAI) of the DCI format received from MO#4 is (1,1), the (counter-DAI, total-DAI) of the DCI format received from MO#5 is (2,2), and the (counter-DAI, total-DAI) of the DCI format received from MO#6 is (1,3).

[0266] As another example of the present invention, we propose a method in which a terminal generates a HARQ-ACK codebook when the bit size of the counter DAI and the bit size of the total DAI are different. As shown in Figure 18(b), the terminal may not be able to receive the DCI formats of MO#4 and MO#5. In this case, the terminal receives a DCI format with a counter-DAI value of 2 in MO#3 and a DCI format with a counter-DAI value of 1 in MO#6, and therefore cannot recognize the failure to receive the DCI formats of MO#4 and MO#5.

[0267] Therefore, the terminal generates only HARQ-ACK bits for the DCI formats received in MO#0, MO#1, MO#2, MO#3, and MO#6 and includes them in the HARQ-ACK codebook.

[0268] If the terminal receives a total-DAI value of 3 in the DCI format for scheduling the PDSCH, the terminal determines that there are two more DCI formats in addition to the five successfully received DCI formats, and therefore the terminal generates HARQ-ACK bits for a total of seven DCI formats and includes them in the HARQ-ACK codebook.

[0269] In one embodiment of the present invention, the total-DAI value and the counter-DAI value are used as follows: First, the counter-DAI value received by the terminal from the most recent MO is V temp As mentioned above, the counter-DAI value is 1, 2, ..., C D The total DAI value received by the terminal in the DCI format for scheduling the PDSCH is V temp2 If so, the terminal generates a HARQ-ACK codebook through the following process.

[0270] First, the device is V temp W is the number of DCI formats scheduled for PDSCH. temp is determined by the following formula 10. [Formula 10] W temp =C D *j+V temp

[0271] In Equation 10, the initial value of j is set to 0, and if the counter-DAI value of the DCI format scheduling the PDSCH in the current MO is smaller than the counter-DAI value of the DCI format scheduling the PDSCH in the previous MO, it is incremented by 1.

[0272] That is, counter-DAI values ​​are 1, 2, …, C D In FIG. 18(a), j=2.

[0273] Next, the terminal determines the number of DCI formats for which PDSCH is scheduled. temp is the bit size of the total-DAI field, N T-DAI V' is the counter-DAI value corresponding to temp This is performed using the following formula 11. [Formula 11] V' temp =((W temp -1)mod T D )+1

[0274] In Equation 11, V' temp is 1, 2, …, T like total-DAI. D The terminal has one of the values ​​V' temp and V temp2 Compare and determine the j value. If V temp2 <V’ temp If so, the j value is calculated by the following equation 12.

number

[0275] Otherwise, j is left as it is. Using the j value, the terminal calculates the size of the HARQ-ACK codebook, O ACK If the terminal is configured to receive only 1 TB per PDSCH, then O ACK is calculated by the following formula 13.

number

[0276] If the terminal is configured to receive 2TB per PDSCH, thenACK is calculated by the following formula 14.

number

[0277] In another embodiment of the present invention, if the bit sizes of the counter-DAI fields of DCI formats 1_0, 1_1, or 1_2 are different from each other, the terminal performs the following operation.

[0278] For monitoring opportunity m, the bit size of the counter-DAI field of DCI format 1_0, 1_1, or 1_2 received by serving cell c is N C-DAI、c、m In this case, the counter-DAI value is 1, 2, ..., 2^N C-DAI、c、m where the largest value C D、c、m is 2^N C-DAI、c、m That is, the bit size of the counter-DAI field is N C-DAI、c、m is 2 bits, if the bit value of the counter-DAI field is "00", it is 1, if it is "01", it is 2, if it is "10", it is 3, if it is "11", it is 4. D The value of N is 4. C-DAI、c、m is 1 bit, the bit value of the counter-DAI field is 0, it is 1, and if it is 1, it is 2. Then, C D、c、m The value of is 2.

[0279] If the UE receives a DCI format for scheduling a PDSCH in serving cell c on monitoring occasion m, and the counter-DAI value of the received DCI format is V C-DAI、c、m If so, the UE assigns a DCI format for scheduling a PDSCH to the current serving cell c of the current monitoring opportunity m in which the DCI format is received as C. D、c、m *j+V C-DAI、c、m It is determined that j is received, where j is a non-negative integer.

[0280] In other words, if the number of DCI formats for scheduling PDSCH up to the current serving cell c of the current monitoring opportunity m in which the DCI format is received is X, then the counter-DAI value V of that DCI format is C-DAI、c、m (X-1 mod C D、c、m )+1.

[0281] In the present invention, when the bit sizes of counter DAI are different, a method for the UE to generate a HARQ-ACK codebook is proposed. In one embodiment of the present invention, the counter-DAI value is used as follows:

[0282] N C-DAI、c、m is the minimum bit size of the counter DAI field in the DCI format, and C D、min The value of is 2^(N C-DAI、min For example, if the bit size of the counter DAI field in one DCI format is 2 bits and the bit size of the counter DAI field in another DCI format is 1 bit, then N C-DAI、min The value is 1, C D、min The value is 2.

[0283] At monitoring opportunity m, the counter-DAI value received by serving cell c is V C-DAI、c、m As mentioned above, the counter-DAI value is 1, 2, ..., C D、c、m First, the terminal has one of the values ​​V C-DAI、c、m The number of DCI formats for which PDSCH is scheduled is S c、m is determined based on the following formula 15.

number

[0284] In Equation 15, floor(j*C D、min / C D、c、m )*C D、c、mThe part is the number of DCI formats scheduled for PDSCH (S c、m ) is (S c、m -1 mod C D、c、m )+1=V C-DAI、c、m This is the part that satisfies the above.

[0285] That is, in Equation 15, the value of j is adjusted by scaling and / or flooring so that the value of becomes a multiple of .

[0286] The terminal is currently monitoring opportunity m, the number of DCI formats acquired based on the counter-DAI value received from serving cell c, S c、m and the number of DCI formats calculated just before, W temp Compare. If S c、m ≦W temp If this is satisfied, then S c、m >W temp The j value is increased until the j value is 1. c、m >W temp If so, keep j as it is.

[0287] j is C D、min This parameter indicates how many DCI formats have been received.

[0288] This can be expressed in pseudocode as shown in Table 12 below. [Table 12-1] [Table 12-2] [Table 12-3]

[0289] In Table 12, when the HARQ-ACK codebook is multiplexed on the PUSCH, T D =U D Then, after the while statement, V temp2is set to the UL DAI value.

[0290] DCI format 1_2 may not include counter-DAI (including being set to 0 bit). In this case, the UE may be uncertain about how to determine the dynamic HARQ-ACK codebook. In other words, when designing a dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook), the base station configures the UE to omit some DCI fields to increase the probability of successful PDCCH reception. In other words, the base station omits some DCI fields or sets the field size to 0 bits.

[0291] For example, the base station omits the counter-DAI field from the DCI field transmitted to the terminal, or sets the size of the field to 0 bits.

[0292] As described above, in the dynamic HARQ-ACK codebook, the counter-DAI field is not only used to determine the position of the HARQ-ACK 1 bit within the HARQ-ACK codebook, but also to determine the size of the HARQ-ACK codebook.

[0293] In order for the terminal to transmit HARQ-ACK bits for notifying the base station of ACK / NACK (or DTX) for multiple PDSCHs to the HARQ-ACK codebook, the counter-DAI field values ​​of the DCI should be sorted in ascending order. However, if the counter-DAI field is omitted, the counter-DAI field values ​​cannot be sorted in ascending order via explicit values, so a method for determining the order of the HARQ-ACK bits in the HARQ-ACK codebook is required.

[0294] Therefore, a method for generating a HARQ-ACK codebook according to a certain criterion will be investigated even when some fields of the DCI are omitted.

[0295] FIG. 20 illustrates an example of a method for transmitting a HARQ-ACK for a PDSCH according to a receiving order of a PDCCH according to an embodiment of the present invention.

[0296] Referring to FIG. 20, if the DAI field is partially omitted or its size is set to 0 bits, the terminal generates a HARQ-ACK codebook according to the order in which the PDCCH for scheduling the PDSCH is received, rather than the counter-DAI value.

[0297] In a first embodiment of the present invention, the terminal determines the order of HARQ-ACK bits for PDSCHs in the HARQ-ACK codebook based on time information when the PDCCHs for scheduling the PDSCHs are received. That is, the terminal determines the order of HARQ-ACK bits included in the HARQ-ACK codebook according to the order in which the PDCCHs are received, regardless of the counter-DAI value of the PDCCHs transmitted for scheduling the PDSCHs.

[0298] For example, as shown in Figure 20(a), if the starting symbol of the CORESET or search space containing the PDCCH that schedules the first PDSCH is located ahead of the starting symbol of the CORESET or search space containing the PDCCH that schedules the second PDSCH, then in the HARQ-ACK codebook, B(1), which is the HARQ-ACK bit of the first PDSCH, is placed ahead of B(0), which is the HARQ-ACK bit of the second PDSCH, as shown in Figure 20(b).If the starting symbols of the CORESET or search space are the same, the last symbol of the CORESET or search space is placed one bit ahead of the HARQ-ACK of the PDSCH scheduled by the previous PDCCH.

[0299] FIG. 21 illustrates an example of a method for transmitting a HARQ-ACK for a PDSCH according to time information of the PDSCH according to an embodiment of the present invention.

[0300] Referring to FIG. 21, if the DAI field is partially omitted or its size is set to 0 bits, the UE generates a HARQ-ACK codebook based on the time information of the PDSCH included in the PDCCH for scheduling the PDSCH, rather than the counter-DAI value.

[0301] In a second embodiment of the present invention, a terminal determines the order of HARQ-ACK bits of PDSCHs constituting a HARQ-ACK codebook according to time information of the PDSCHs. Specifically, if the start symbol of the first PDSCH is located before the start symbol of the second PDSCH, the HARQ-ACK bit for the first PDSCH is located before the HARQ-ACK bit for the second PDSCH in the HARQ-ACK codebook.

[0302] For example, as shown in Figure 21(a), the start symbol of the second PDSCH is positioned before the start symbol of the first PDSCH based on time information included in the PDCCH for scheduling the first PDSCH and time information included in the PDCCH for scheduling the second PDSCH. In this case, as shown in Figure 21(b), when the terminal transmits HARQ-ACK for the first PDSCH and HARQ-ACK for the second PDSCH via PUCCH, the HARQ-ACK bit B(1) for the second PDSCH is positioned before the HARQ-ACK bit B(0) for the first PDSCH.

[0303] FIG. 22 is a diagram illustrating an example of transmitting a HARQ-ACK for a PDSCH according to a HARQ process ID (or HARQ process number) of a PDCCH that schedules a PDSCH according to an embodiment of the present invention.

[0304] Referring to FIG. 22, if the DAI field is partially omitted or its size is set to 0 bits, the terminal generates a HARQ-ACK codebook based on the HARQ process ID (or HARQ process number) included in the PDCCH for scheduling the PDSCH, rather than the counter-DAI value.

[0305] In a third embodiment of the present invention, the terminal determines the order of the HARQ-ACK bits in the HARQ-ACK codebook according to the HARQ process ID (or HARQ process number) value of the PDCCH that schedules the PDSCH.

[0306] In detail, if the HARQ process ID of the first PDSCH in the PDCCH that schedules the first PDSCH is A and the HARQ process ID of the second PDSCH in the PDCCH that schedules the second PDSCH is B, the HARQ-ACK bit of the PDSCH that has the smaller value of A or B in the HARQ-ACK codebook is placed at a position before the HARQ-ACK bit of the PDSCH that has the larger value.

[0307] That is, the position of the HARQ-ACK bit is determined in ascending order of the HARQ-ACK process ID. Here, the UE assumes that the HARQ process IDs of HARQ-ACKs transmitted in one HARQ-ACK codebook are different from each other. Therefore, it is not expected that one HARQ-ACK codebook will be generated with the HARQ-ACK bits of PDSCHs having the same HARQ process ID.

[0308] For example, if the number of bits of the counter-DAI field included in at least one of the PDCCH scheduling the first PDSCH and the PDCCH scheduling the second PDSCH is different from each other, omitted, or set to 0 bit, the terminal generates a HARQ-ACK codebook based on the HARQ-ACK process ID included in the PDCCH scheduling each PDSCH and transmits it to the base station via UCI.

[0309] In this case, as shown in Figure 22(a), the value of the HARQ-ACK process ID or HARQ-ACK process number of the PDCCH for scheduling the second PDSCH is "0", and the value of the HARQ-ACK process ID or HARQ-ACK process number of the PDCCH for scheduling the first PDSCH is "1". In this case, as shown in Figure 15(b), based on the ascending order of the HARQ-ACK process IDs or HARQ-ACK process numbers, the HARQ-ACK bit B(0) for the second PDSCH having a lower HARQ-ACK process ID or HARQ-ACK process number is located at a bit earlier than the HARQ-ACK bit B(1) for the first PDSCH.

[0310] In a fourth embodiment of the present invention, a terminal determines the order of HARQ-ACK bits of PDSCHs in a HARQ-ACK codebook using information about cells that have received PDCCHs scheduling each PDSCH. Cell information refers to the index (or ID) of a cell. The terminal is configured to monitor PDCCHs in multiple cells. In this case, the terminal receives different PDCCHs in different cells. In the HARQ-ACK codebook, the terminal arranges the order of HARQ-ACK bits of PDSCHs received in different cells in ascending order of the index of the cell that received the PDCCH scheduling the PDSCH.

[0311] In a fifth embodiment of the present invention, a terminal determines the order of HARQ-ACK bits of a PDSCH by using information about a CORESET (or search space) received on a PDCCH that schedules a PDSCH, and generates a HARQ-ACK codebook. Here, the information about the CORESET (or search space) is the index (or ID) of the CORESET (or search space).

[0312] The UE is configured to monitor PDCCHs in multiple CORESETs (or search spaces). In this case, the UE receives different PDCCHs in different CORESETs (or search spaces). In this case, the UE generates a HARQ-ACK codebook by arranging the order of HARQ-ACK bits of PDSCHs received in different CORESETs (or search spaces) in ascending order of the index of the CORESET (or search space) that received the PDCCH that schedules the PDSCH.

[0313] In a sixth embodiment of the present invention, a UE determines the order of HARQ-ACK bits of the PDSCH in a HARQ-ACK codebook using frequency domain information of a PDCCH that schedules a PDSCH. Here, the frequency domain information is the lowest PRB index among PRBs to which a PDCCH is assigned. Here, the index refers to a common PRB index, which indicates how far the index is from Point A in the frequency domain. Point A refers to the reference frequency in the UE's initial access process, and Point A is as follows:

[0314] - fsetToPointA indicates the frequency offset between Point A and the lowest subcarrier of the lowest resource block. The lowest resource block has a subcarrier spacing given by the higher layer parameter SubCarrierSpacingCommon and overlaps with the SS / PBCH block used by the terminal for initial cell selection. offsetToPointA is expressed in resource block units, assuming a 15 kHz subcarrier spacing for FR1 and a 60 kHz subcarrier spacing for FR2.

[0315] The absoluteFrequencyPointA indicating the frequency location of Point A is expressed as an Absolute Radio Frequency Channel Number (ARFCN) for all other cases.

[0316] The terminal is configured to monitor multiple PDCCHs and receive different PDCCHs in different frequency regions. In this case, the terminal arranges the order of HARQ-ACK bits of PDSCHs received in different frequency regions in the HARQ-ACK codebook in ascending order of the lowest PRB index of the PDCCH that schedules the PDSCH. In this method, when multiple PDCCHs are received by the terminal in one CORESET (or search space) in the fifth embodiment, the order of HARQ-ACK bits is determined by the HARQ-ACK codebook.

[0317] The first to sixth embodiments are used in combination with one another, whereby the terminal determines the order of HARQ-ACK bits for each PDSCH in the HARQ-ACK codebook. For example, the first embodiment and the third embodiment are combined. In this combination, the order of HARQ-ACK bits in the HARQ-ACK codebook is first determined by time-domain information of the PDCCH. If the order cannot be determined by the time-domain information, the order is determined by the HARQ process ID in the third embodiment. Alternatively, the first, fourth, fifth, and sixth embodiments are combined. In this combination, the order of HARQ-ACK bits in the HARQ-ACK codebook is first determined by time-domain information of the PDCCH. Next, if the order cannot be determined by time-domain information in each embodiment, the order is determined by cell information. If the order cannot be determined by cell information, the order is determined by CORESET (or search space) information. Furthermore, if the order cannot be determined by CORESET (or search space) information, the order is determined by frequency-domain allocation information of the PDCCH.

[0318] In another embodiment of the present invention, when PDSCHs are scheduled via multiple PDCCHs and the number of bits of the counter-DAI fields included in the multiple PDCCHs are different from each other, the UE does not multiplex HARQ-ACK codebooks according to the number of bits, but generates them individually according to the number of bits of the counter-DAI.

[0319] For example, if the number of bits of the counter-DAI field is 2 bits or 1 bit, the terminal separately generates a HARQ-ACK codebook for the PDSCHs scheduled by the PDCCH including the counter-DAI with 2 bits and / or a HARQ-ACK codebook for the PDSCHs scheduled by the PDCCH including the counter-DAI with 1 bit, and transmits them to the base station.

[0320] That is, one HARQ-ACK codebook for a terminal includes only HARQ-ACKs of PDSCHs scheduled in DCI formats having the same number of counter-DAI bits.

[0321] According to the first to sixth embodiments described above, the UE determines the position of the HARQ-ACK bit in the HARQ-ACK codebook without the counter-DAI field. However, when the UE generates a HARQ-ACK codebook including HARQ-ACK bits for each PDSCH, a problem may occur in determining the size of the HARQ-ACK codebook.

[0322] For example, if a terminal is unable to receive one of the PDCCHs, the terminal may make an incorrect determination of the size of the HARQ-ACK codebook due to the PDCCH that it was unable to receive, so a method for resolving this is needed.

[0323] In this case, the terminal always assumes that when the size of the dynamic HARQ-ACK codebook is divided by X, the remainder is Y. Preferably, X=4 and Y=1. That is, the size of the dynamic HARQ-ACK codebook is determined to be one of 1, 5, 9, ... bits. If the terminal receives a PDCCH scheduling Z PDSCHs, the terminal determines the size of the HARQ-ACK codebook to be the smallest value greater than or equal to Z. For example, if Z=3, the terminal determines the size of the HARQ-ACK codebook to be 5.

[0324] The DCI of the PDCCH corresponding to the HARQ-ACK of one HARQ-ACK codebook may or may not include a counter-DAI field. In this case, the UE shall determine the position of the HARQ-ACK of the PDSC scheduled by the DCI including the counter-DAI field and the HARQ-ACK of the PDSCH scheduled by the DCI without the counter-DAI field within the HARQ-ACK codebook.

[0325] In this case, as an embodiment of the present invention, the terminal generates a HARQ-ACK codebook separately depending on whether the DCI includes a counter-DAI field or not.

[0326] In detail, the UE generates a first sub-HARQ-ACK codebook by collecting only HARQ-ACKs of PDSCHs scheduled by DCIs containing a counter-DAI field. In this case, the position of the HARQ-ACK in the first sub-HARQ-ACK codebook is determined using the value of the counter-DAI field (i.e., the position is determined in ascending order of the counter-DAI). In this case, if the number of bits of the counter-DAI field is different from each other, the methods of the first to sixth embodiments described above and their combinations are used.

[0327] Then, the UE generates a second sub-HARQ-ACK codebook by collecting only the HARQ-ACKs of PDSCHs scheduled by DCIs in which the counter-DAI field is omitted or set to 0 bit. In this case, the position of the HARQ-ACK in the second sub-HARQ-ACK codebook is determined according to the first to sixth embodiments and their combinations. The UE generates a HARQ-ACK codebook by consecutively combining the first sub-HARQ-ACK codebook and the second sub-HARQ-ACK codebook (i.e., the last bit of the first sub-HARQ-ACK codebook is followed by the first bit of the second sub-HARQ-ACK codebook). This method may increase the UE's complexity because the UE must generate two sub-HARQ-ACK codebooks in different manners.

[0328] In another embodiment of the present invention, in the above situation, the UE ignores the counter-DAI field included in the DCI, i.e., it regards all DCIs as DCIs without a counter-DAI field, and determines the position of the HARQ-ACK bit in the HARQ-ACK codebook according to the first to sixth embodiments and combinations thereof.

[0329] In another embodiment of the present invention, a terminal configured with a semi-static HARQ-ACK codebook determines a HARQ-ACK bit for one PDSCH.

[0330] Specifically, a terminal configured with a semi-static HARQ-ACK codebook should transmit a HARQ-ACK codebook including a predetermined number of HARQ-ACK bits on the PUCCH. In this case, the predetermined number is determined regardless of which PDSCH the terminal is actually scheduled for and is derived from information configured with a higher layer.

[0331] The information configured with the higher layer includes at least the CBG configuration information of the cell, and the UE is configured with the CBG configuration information for each cell. The CBG configuration information is used to configure the maximum number of CBGs that can be included in one PDSCH (or TB), and N MAX In the semi-static HARQ-ACK codebook, when HARQ-ACK bits of PDSCHs are included, it is necessary to determine how many bits of HARQ-ACK one PDSCH corresponds to. Generally, if CBG transmission is not configured, PDSCH corresponds to 1 bit HARQ-ACK (2 bits if 2TB transmission is configured), and if CBG transmission is configured, PDSCH corresponds to N MAX bits HARQ-ACK.

[0332] If semi-static HARQ-ACK is configured in the UE, the number of HARQ-ACK bits determined as above should be included in the PUCCH. Even if CBG-based transmission is configured, in certain situations, the UE transmits only 1-bit HARQ-ACK for the PDSCH in the PUCCH.

[0333] For example, if CBG-based transmission is configured, one downlink cell (or carrier) is configured in the UE while satisfying at least one of the following cases, and if there is one monitoring opportunity to receive a PDCCH, the UE generates only 1 bit of the SPS PDSCH, or SPS PDSCH release DCI, or HARQ-ACK of the PDSCH.

[0334] If the UE needs to transmit HARQ-ACK for one SPS PDSCH,

[0335] When one SPS PDSCH release DCI is received,

[0336] When transmitting HARQ-ACK for PDSCH scheduled with DCI format 1_0 or DCI format 1_2

[0337] That is, even if CBG-based transmission is configured, the terminal generates only 1-bit HARQ-ACK per PDSCH.

[0338] Conversely, when CBG-based transmission is configured, if at least one of the following conditions is satisfied, and two or more downlink cells (or carriers) are configured in the UE, or there are two or more monitoring opportunities to receive the PDCCH, the UE sends the SPS PDSCH, SPS PDSCH release DCI, or PDSCH HARQ-ACK (TB-level HARQ-ACK) 1 bit to the UE. MAX Repeat N times MAX Generates bits.

[0339] When HARQ-ACK for one SPS PDSCH should be transmitted,

[0340] When one SPS PDSCH release DCI is received,

[0341] When transmitting HARQ-ACK for PDSCH scheduled with DCI format 1_0 or DCI format 1_2

[0342] In other words, in accordance with the CBG-based transmission, the terminal MAX Only generate HARQ-ACK for 1000 bits.

[0343] In the above operation, DCI format 1_2 is a DCI format that sets the size of each field for high reliability and low latency. This DCI format 1_2 does not support CBG-based operation. That is, PDSCH scheduled in DCI format 1_2 always corresponds to 1 bit of TB-level HARQ-ACK. This is similar to DCI format 1_0. Therefore, it is treated the same as DCI format 1_0.

[0344] FIG. 23 is a flowchart illustrating an example of a UE operation for transmitting a HARQ-ACK based on downlink information having different formats according to an embodiment of the present invention.

[0345] 23, the UE generates a HARQ-ACK codebook including HARQ-ACK bits for a plurality of PDSCHs scheduled by DCIs of a plurality of PDCCHs transmitted from a base station. In this case, if the formats of the DCIs are different and the number of bits of the DAI fields included in each DCI is different, the UE interprets the value of the DAI field according to a certain condition to generate the HARQ-ACK codebook.

[0346] First, the terminal receives a first PDCCH for scheduling a first physical downlink shared channel (PDSCH) S23010. At this time, before receiving the first PDCCH, the terminal receives configuration information including information for receiving the PDCCH.

[0347] The first PDCCH includes a first counter downlink allocation indicator (DAI) indicating the number of PDSCHs scheduled in the serving cell up to the time the first PDCCH is monitored, and a first total DAI indicating the number of all PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored.

[0348] Next, the terminal receives a second PDCCH for scheduling a second PDSCH including the second counter DAI and the second overall DAI (S23020).

[0349] Next, the terminal receives the first PDSCH based on the first PDCCH (S23030) and receives the second PDSCH based on the second PDCCH (S23040).

[0350] After receiving the first PDSCH and the second PDSCH, the terminal generates HARQ-ACK bits for the first PDSCH and the second PDSCH, respectively, and generates a HARQ-ACK codebook using the generated HARQ-ACK bits.

[0351] Next, the terminal transmits uplink control information (UCI) including the HARQ-ACK codebook to the base station S23050.

[0352] When the number of bits of the first counter DAI and the number of bits of the second counter DAI are different, the value of the second counter DAI is determined based on the number of bits of the first counter DAI. That is, when the number of bits of the first counter DAI and the number of bits of the second counter DAI are different, the terminal generates a HARQ-ACK codebook including HARQ-ACK bits according to the methods of Proposals 1 to 3 described above.

[0353] For example, if the number of bits of the first counter DAI is smaller than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI, the number of which is the same as the number of bits of the first counter DAI.

[0354] Alternatively, if the number of bits of the first counter DAI is greater than the number of bits of the second counter DAI, the value indicated by the second counter DAI is interpreted by expanding the number of bits until the number of bits of the second counter DAI is the same as the number of bits of the first counter DAI.

[0355] In this case, if there are multiple candidate values ​​for the second counter DAI, the value of the second counter DAI is interpreted as the value that is the smallest difference from the value indicated by the first counter DAI among the multiple candidate values.

[0356] FIG. 24 is a flowchart illustrating an example of a base station operation for receiving HARQ-ACK based on downlink information having different formats according to an embodiment of the present invention.

[0357] 24, a base station schedules PDSCHs to a UE through a plurality of PDCCHs having different formats. In this case, if the number of bits of the DCI field included in the DCI of different formats of the PDCCH is different, the base station transmits HARQ-ACK codebooks for the PDSCHs scheduled by the DCI of different formats from the UE.

[0358] First, the base station transmits a first PDCCH for scheduling a first physical downlink shared channel (PDSCH) to the terminal (S24010). At this time, before transmitting the first PDCCH, the base station transmits configuration information including information for receiving the PDCCH.

[0359] The first PDCCH includes a first counter downlink allocation indicator (DAI) indicating the number of PDSCHs scheduled in the serving cell up to the time the first PDCCH is monitored, and a first total DAI indicating the number of all PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored.

[0360] Next, the base station transmits a second PDCCH for scheduling a second PDSCH including the second counter DAI and the second overall DAI (S24020).

[0361] Next, the base station transmits the first PDSCH based on the first PDCCH (S24030) and transmits the second PDSCH based on the second PDCCH (S24040).

[0362] The base station receives a HARQ-ACK codebook including HARQ-ACK bits for the first PDSCH and the second PDSCH generated by the terminal from the terminal via uplink control information (UCI) S24050.

[0363] When the number of bits of the first counter DAI and the number of bits of the second counter DAI are different, the value of the second counter DAI is determined based on the number of bits of the first counter DAI. That is, when the number of bits of the first counter DAI and the number of bits of the second counter DAI are different, the terminal generates a HARQ-ACK codebook including HARQ-ACK bits according to the methods of Proposals 1 to 3 described above.

[0364] For example, if the number of bits of the first counter DAI is smaller than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI, the number of which is the same as the number of bits of the first counter DAI.

[0365] Alternatively, if the number of bits of the first counter DAI is greater than the number of bits of the second counter DAI, the value indicated by the second counter DAI is interpreted by expanding the number of bits until the number of bits of the second counter DAI is the same as the number of bits of the first counter DAI.

[0366] In this case, if there are multiple candidate values ​​for the second counter DAI, the value of the second counter DAI is interpreted as the value that is the smallest difference from the value indicated by the first counter DAI among the multiple candidate values.

[0367] 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, it should be understood that the above-described embodiments are illustrative in all respects and are not limiting. For example, each component described as a single component may be implemented in a distributed form, and components described as distributed may also be implemented in a combined form.

[0368] The scope of the present invention is indicated by the claims 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 interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0369] 100 devices 110 processors 120 Communication Module 130 memory 140 User Interface 150 display units 200 base stations 210 processor 220 Communication Module 230 memory

Claims

1. 1. A terminal configured to operate in a wireless communication system, comprising: a communication module; a processor for controlling the communication module; The processor: receiving a plurality of first Downlink Control Information (DCI) formats for downlink scheduling, each of the plurality of first DCI formats including an Nc-bit counter-downlink allocation index (c-DAI), where Nc is one of 1 and 2; receiving a second DCI format for scheduling a Physical Uplink Shared Channel (PUSCH), the second DCI format including a 2-bit uplink DAI (UL-DAI); and transmitting a Hybrid Automatic Repeat Request (HARQ)-acknowledge (ACK) codebook for the downlink scheduling via the PUSCH; configured to: The bit size of the HARQ-ACK codebook is i) a first value: 4*floor(j*C / 4)+V, or ii) a second value that is 4 greater than the first value; and O having j is the value of the counter for cases where the value of the Nc-bit c-DAI is less than or equal to the value of a previous Nc-bit c-DAI within the plurality of received Nc-bit c-DAIs; C is 2^Nc, V is the value of the 2-bit UL-DAI, ranging from 1 to 4; floor is the flooring function, Terminal.

2. The terminal of claim 1 , wherein Nc is 1.

3. The terminal according to claim 1 or 2, wherein the bit size of the HARQ-ACK codebook is determined as O or P*O, where P is a positive integer.

4. O has said second value only when V is less than Vtemp; 4. The terminal of claim 1, wherein when Nc is 1, Vtemp is determined as a 2-bit c-DAI value converted from the last one of the received Nc-bit c-DAI values, such that the 2-bit c-DAI value converted from the last one of the received Nc-bit c-DAI values ​​is associated with the number of downlink scheduling operations determined based on the received Nc-bit c-DAIs.

5. The value of the last one of the plurality of received Nc-bit c-DAIs and the converted 2-bit c-DAI value satisfy a relationship comprising the following table: Table 1 5. The terminal of claim 4, wherein X represents the value of the last one of the plurality of received Nc-bit c-DAIs, and Y represents the converted 2-bit c-DAI value.

6. The terminal according to claim 1 , wherein the Nc-bit c-DAI in each of the plurality of first DCI formats is associated with a bit position of corresponding HARQ-ACK information in the HARQ-ACK codebook.

7. 7. The terminal according to claim 1, wherein the Nc-bit c-DAI in each of the plurality of first DCI formats is associated with a value of a counter of a corresponding downlink scheduling, and the 2-bit UL-DAI is associated with a total number of the downlink scheduling.

8. The terminal of claim 1 , wherein the wireless communication system comprises a 3rd generation partnership project (3GPP) based wireless communication system.

9. 1. A method implemented by a terminal in a wireless communication system, comprising: receiving a plurality of first Downlink Control Information (DCI) formats for downlink scheduling, each of the plurality of first DCI formats including an Nc-bit counter-downlink allocation index (c-DAI), where Nc is one of 1 and 2; receiving a second DCI format for scheduling a Physical Uplink Shared Channel (PUSCH), the second DCI format including a 2-bit uplink DAI (UL-DAI); and transmitting a Hybrid Automatic Repeat Request (HARQ)-acknowledge (ACK) codebook for the downlink scheduling via the PUSCH; Including, The bit size of the HARQ-ACK codebook is i) a first value: 4*floor(j*C / 4)+V, or ii) a second value that is 4 greater than the first value; and O having j is the value of the counter for cases where the value of the Nc-bit c-DAI is less than or equal to the value of a previous Nc-bit c-DAI within the plurality of received Nc-bit c-DAIs; C is 2^Nc, V is the value of the 2-bit UL-DAI, ranging from 1 to 4; floor is the flooring function, method.

10. 10. The method of claim 9, wherein Nc is 1.

11. The method according to claim 9 or 10, wherein the bit size of the HARQ-ACK codebook is determined as O or P*O, where P is a positive integer.

12. O has said second value only when V is less than Vtemp; 12. The method of claim 9, wherein when Nc is 1, Vtemp is determined as a 2-bit c-DAI value converted from a last one of the plurality of received Nc-bit c-DAIs, such that the converted 2-bit c-DAI value is associated with the number of downlink scheduling operations determined based on the plurality of received Nc-bit c-DAIs.

13. The value of the last one of the plurality of received Nc-bit c-DAIs and the converted 2-bit c-DAI value satisfy a relationship comprising the following table: Table 2 13. The method of claim 12, wherein X represents the value of the last one of the plurality of received Nc-bit c-DAIs, and Y represents the converted 2-bit c-DAI value.

14. 14. The method according to claim 9, wherein the Nc-bit c-DAI in each of the first DCI formats is associated with a bit position of corresponding HARQ-ACK information in the HARQ-ACK codebook.

15. 15. The method according to claim 9, wherein the Nc-bit c-DAI in each of the plurality of first DCI formats is associated with a value of a counter of a corresponding downlink scheduling, and the 2-bit UL-DAI is associated with a total number of the downlink scheduling.

16. 16. The method of any one of claims 9 to 15, wherein the wireless communication system comprises a 3rd generation partnership project (3GPP) based wireless communication system.

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