Method, apparatus and system for downlink data reception and harq-ack transmission in wireless communication system

Abstract

The present disclosure relates to methods, apparatuses and systems for downlink reception and HARQ-ACK transmission in a wireless communication system. According to the present disclosure, in the methods, apparatuses and systems for downlink reception and HARQ-ACK transmission, a first physical downlink control channel (PDCCH) for scheduling a first physical downlink shared channel (PDSCH) is received, and a second PDCCH for scheduling a second PDSCH is received. Thereafter, uplink control information (UCI) including a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebook for the first PDSCH and the second PDSCH is transmitted to a base station.

Description

[0001] This application is a divisional application of the patent application with the application number 202080042075.X (PCT / KR2020 / 005923) filed in the Chinese Patent Office on December 7, 2021 for the international application with the international filing date of May 4, 2020, the title of which is "Method, apparatus and system for downlink data reception and HARQ-ACK transmission in wireless communication system". TECHNICAL FIELD

[0002] The present disclosure relates to a wireless communication system, and more particularly, the present disclosure relates to transmission of downlink data and transmission of acknowledgement thereof in a wireless communication system. BACKGROUND

[0003] 3GPP LTE(-A) defines uplink / downlink physical channels to transmit physical layer signals. For example, a physical uplink shared channel (PUSCH) as a physical channel for transmitting data through an uplink, a physical uplink control channel (PUCCH) for transmitting a control signal, a physical random access channel (PRACH), and the like are defined, and there are a physical downlink shared channel (PDSCH) for transmitting data to a downlink, and a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), a physical hybrid-ARQ indicator channel (PHICH), and the like for transmitting L1 / L2 control signals.

[0004] The downlink control channel (PDCCH / EPDCCH) among the above channels is a channel for the base station to transmit uplink / downlink scheduling allocation control information, uplink transmission power control information, and other control information to one or more user equipments. Since the resources available for the PDCCH that can be transmitted by the base station at one time are limited, different resources cannot be allocated to each user equipment, and control information should be transmitted to any user equipment by sharing resources. For example, in 3GPP LTE(-A), four resource elements (REs) can be grouped to form a resource element group (REG), nine control channel elements (CCEs) can be generated, resources capable of combining and transmitting one or more CCEs can be notified to the user equipment, and multiple user equipments can share and use the CCEs. Here, the number of combined CCEs is referred to as a CCE aggregation level, and the resources to which CCEs are allocated according to the possible CCE aggregation levels are referred to as a search space. The search space can include a common search space defined for each base station and a terminal-specific or UE-specific search space defined for each user equipment. The user equipment performs decoding for multiple cases of all possible CCE combinations in the search space, and can identify whether the user equipment belongs to the PDCCH by a user equipment (UE) identifier included in the PDCCH. Therefore, such an operation of the user equipment requires a long time to decode the PDCCH, and inevitably causes a large amount of energy consumption.

[0005] Efforts are being made to develop an improved 5G communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of the 4G communication system. To this end, the 5G communication system or the pre-5G communication system is called a beyond 4G network communication system or a post LTE system. Consideration is given to implementing the 5G communication system in an ultra-high frequency (mmWave) band (e.g., 60-GHz band) to achieve high data transmission rates. To reduce radio propagation path loss and increase a transmission distance of radio waves in the ultra-high frequency band, beamforming, massive MIMO, full dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large scale antenna techniques are discussed in the 5G communication system field. Further, to improve networks of the system, technologies such as advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), interference mitigation, and the like are developed in the 5G communication system field. In addition, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), which are an advanced coding modulation (ACM) scheme, and filter bank multi-carrier (FBMC), orthogonal time frequency space (OTFS), and sparse code multiple access (SCMA), which are an advanced access technology, are developed in the 5G system field.

[0006] Meanwhile, in a human centric connected network in which humans generate and consume information, the Internet has evolved into an Internet of Things (IoT) network that exchanges information between distributed components such as things. Internet of Everything (IoE) technology, which is a combination of the IoT technology and a big data processing technology through a connection with a cloud server, is also on the rise. To implement the IoT, technical elements such as a sensing technology, wired / wireless communication and network infrastructure, service interface technology, and a security technology are required, and in recent years, technologies such as a sensor network, Machine to Machine (M2M), and Machine Type Communication (MTC) have been researched to connect things. In the IoT environment, intelligent Internet Technology (IT) services that collect and analyze data generated from connected things to create new value in people's lives can be provided. The IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart home appliances, and advanced medical services through the convergence and hybridization of existing information technology (IT) and various industries.

[0007] Here, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as a sensor network, Machine to Machine (M2M), and Machine Type Communication (MTC) are implemented using the 5G communication technology, i.e., beamforming, MIMO, array antenna, etc. Application of a cloud Radio Access Network (cloud RAN) as the above-described big data processing technology can be an example of convergence of the 5G technology and the IoT technology.

[0008] Generally, a mobile communication system has been developed to provide a voice service while protecting the activities of users. However, the field of the mobile communication system has been expanded not only to the voice service but also to the data service, and has been developed to provide a high-speed data service at the present time. However, in the mobile communication system for providing a service at the present time, a resource shortage phenomenon occurs, and users need a more high-speed service. Therefore, a more advanced wireless communication system is required.

[0009] As described above, as new applications such as real-time control and tactile internet appear, a future 5G technology needs a lower data transmission delay, and a required delay of 5G data is expected to be reduced to 1 ms. The purpose of 5G is to provide a data delay that is reduced by about 10 times compared to the existing technology. In order to solve this problem, it is expected to propose a 5G communication system that uses a mini-slot having a shorter TTI interval (for example, 0.2 ms) in addition to the existing slot (or subframe).

[0010] In Rel-16 enhanced URLLC (eURLLC), various techniques for providing lower latency time and higher reliability are discussed. In order to provide lower latency, transmission of an uplink control channel including two or more HARQ-ACKs in a single slot is supported. A user equipment is able to transmit a HARQ-ACK as a response to successful reception of a downlink shared channel as fast as possible, thereby ensuring lower latency time. SUMMARY

[0011] Technical problem

[0012] The present disclosure relates to a method for designing a semi-static HARQ-ACK codebook in a 3GPP NR system and a method for transmitting a PUCCH, and an object of the present disclosure is to provide a method capable of solving problems occurring in a case in which a PDSCH and a PUCCH are repeatedly transmitted in multiple slots and an apparatus therefor.

[0013] Those skilled in the art will understand that the objects achievable by the present disclosure are not limited to those specifically described above, and the above and other objects achievable by the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0014] Technical scheme

[0015] A user equipment of a wireless communication system according to an embodiment of the present disclosure includes a communication module and a processor controlling the communication module. The processor receives a first physical downlink control channel (PDCCH) for scheduling a first physical downlink shared channel (PDSCH), the first PDCCH including a first counter downlink assignment indicator (DAI) indicating a number of scheduled PDSCHs of a serving cell up to a time point of monitoring the first PDCCH and a first total DAI indicating a number of all PDSCHs scheduled in the serving cell up to the time point of monitoring the PDCCH, receives a second PDCCH for scheduling a second PDSCH, the second PDCCH including a second counter DAI and a second total DAI, receives the first PDSCH based on the first PDCCH, receives the second PDSCH based on the second PDCCH, and transmits, to the base station, uplink control information (UCI) including a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebook for the first PDSCH and the second PDSCH, wherein when a number of bits of the first counter DAI is different from a number of bits of the second counter DAI, a value of the second counter DAI is determined based on the number of bits of the first counter DAI.

[0016] Further, in the disclosure, when the number of bits of the first counter DAI is smaller than the number of bits of the second counter DAI, a value indicated by the second counter DAI is determined based on at least one of the bits among the bits of the second counter DAI whose number is equal to the number of bits of the first counter DAI.

[0017] Further, in the disclosure, when there are a plurality of values determined by at least one bit among the bits of the second counter DAI whose number is equal to the number of bits of the first counter DAI, the value of the second counter DAI is determined to be a value among the plurality of values which has the smallest difference from the value indicated by the first counter DAI.

[0018] Further, in the disclosure, when 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 a least significant bit (LSB) or a most significant bit (MSB) among the 2 bits.

[0019] Further, in the disclosure, when the 1 bit of the first counter DAI is "0", when 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 when the LSB or the MSB of the second counter DAI is "1", the value of the second counter DAI is determined to be "1".

[0020] Further, in the disclosure, when the 1 bit of the first counter DAI is "1", when the LSB or the MSB of the second counter DAI is "1", the value of the second counter DAI is determined to be "1", and when the LSB or the MSB of the second counter DAI is "0", the value of the second counter DAI is determined to be "2".

[0021] Further, in the disclosure, when the number of bits of the first counter DAI is greater than the number of bits of the second counter DAI, a value indicated by the second counter DAI is determined by extending 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.

[0022] Further, in the disclosure, when there are a plurality of second counter DAI values determined by being extended 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 a value among the plurality of values which has the smallest difference from the value indicated by the first counter DAI,

[0023] Further, in the disclosure, when 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 extending 1 bit to 2 bits.

[0024] Further, in the disclosure, when the 2 bits of the first counter DAI are "00" or "01" and the 1 bit of the second counter DAI is "0", the second counter DAI is determined as "3", and when the 2 bits of the first counter DAI are "10" or "11" and the 1 bit of the second counter DAI is "1", the second counter DAI is determined as "1".

[0025] Further, in the disclosure, when the 2 bits of the first counter DAI are "01" or "10" and the 1 bit of the second counter DAI is "1", the second counter DAI is determined as "4", and when the 2 bits of the first counter DAI are "00" or "11" and the 1 bit of the second counter DAI is "1", the second counter DAI is determined as "2".

[0026] Further, the disclosure provides a method, including: receiving a first physical downlink control channel (PDCCH) for scheduling a first physical downlink shared channel (PDSCH), the first PDCCH including a first counter downlink assignment indicator (DAI) indicating a number of scheduled PDSCHs of a serving cell up to a time point of monitoring the first PDCCH and a first total DAI indicating a number of all PDSCHs scheduled in the serving cell up to the time point of monitoring the PDCCH; 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 transmitting, to the base station, uplink control information (UCI) including a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebook for the first PDSCH and the second PDSCH, wherein when a number of bits of the first counter DAI is different from a number of bits of the second counter DAI, a value of the second counter DAI is determined based on the number of bits of the first counter DAI.

[0027] Beneficial effects

[0028] According to embodiments of the disclosure, the UE can transmit a PUCCH including two or more HARQ-ACKs in one slot. In this case, the coverage of the PUCCH can be increased by reducing the number of HARQ-ACKs that can be owned by each PUCCH.

[0029] Further, according to embodiments of the present disclosure, there is an effect that HARQ-ACK information for PDSCHs scheduled by downlink control information having different formats can be multiplexed and transmitted.

[0030] Further, according to embodiments of the present disclosure, HARQ-ACK information for PDSCHs scheduled by different downlink control information is multiplexed and transmitted, and thus an effect of reducing signaling overhead for transmission of HARQ-ACK information is generated.

[0031] Further, according to embodiments of the present disclosure, a HARQ-ACK bit sequence having small overhead of downlink control information (e.g., DCI) can be determined, and thus an effect of improving transmission efficiency of a network between a base station and a UE is generated.

[0032] Effects obtainable from the present disclosure are not limited to the above-mentioned effects and other effects not mentioned herein will become apparent to those skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 FIG. 1 illustrates an example of a radio frame structure used in a wireless communication system.

[0034] Figure 2 FIG. 2 illustrates an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system.

[0035] Figure 3 FIG. 3 is a diagram for explaining a physical channel used in a 3GPP system and a typical signal transmission method using the same.

[0036] Figure 4 FIG. 4 illustrates an SS / PBCH block for initial cell access in a 3GPP NR system.

[0037] Figure 5 FIG. 5 illustrates a procedure for transmitting control information and a control channel in a 3GPP NR system.

[0038] Figure 6 FIG. 6 illustrates a control resource set (CORESET) in which a physical downlink control channel (PUCCH) can be transmitted in a 3GPP NR system.

[0039] Figure 7 FIG. 7 illustrates a method for configuring a PDCCH search space in a 3GPP NR system.

[0040] Figure 8 FIG. 8 is a conceptual diagram illustrating carrier aggregation.

[0041] Figure 9 FIG. 9 is a diagram for explaining signal carrier communication and multi-carrier communication.

[0042] Figure 10 is a diagram illustrating an example in which a cross-carrier scheduling technique is applied.

[0043] Figure 11 is a block diagram illustrating a configuration of a user equipment and a base station according to an embodiment of the present disclosure.

[0044] Figure 12 is a flowchart illustrating an example of signaling between a user equipment and a base station to which an embodiment of the present disclosure is applicable.

[0045] Figure 13 illustrates an example of a method for counting, by a user equipment, a number of PDSCHs transmitted from a base station based on a pseudo code, which is applicable to an embodiment of the present disclosure.

[0046] Figure 14 illustrates an example of a method for transmitting HARQ-Ack based on downlink control information having different formats according to an embodiment of the present disclosure.

[0047] Figure 15 illustrates another example of a method for transmitting HARQ-Ack based on downlink control information having different formats according to an embodiment of the present disclosure.

[0048] Figure 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 disclosure.

[0049] Figure 17 illustrates an example of a downlink assignment indicator of each downlink control information detected in a monitoring occasion according to an embodiment of the present disclosure.

[0050] Figure 18 illustrates an example of a method for transmitting HARQ-ACK based on downlink control information having different formats based on a pseudo code according to an embodiment of the present disclosure.

[0051] Figure 19 illustrates an example of a downlink assignment indicator of each downlink control information detected in a monitoring occasion according to an embodiment of the present disclosure.

[0052] Figure 20 illustrates an example of a method for transmitting HARQ-ACK for PDSCH according to a reception order of PDCCH according to an embodiment of the present disclosure.

[0053] Figure 21 illustrates an example of a method for transmitting HARQ-ACK for PDSCH according to time information about PDSCH according to an embodiment of the present disclosure.

[0054] Figure 22 FIG. 6 is a flowchart illustrating a transmission of HARQ-ACK for a PDSCH according to a HARQ process ID (or HARQ process number) of a PDCCH for scheduling the PDSCH according to an embodiment of the disclosure.

[0055] Figure 23 FIG. 7 is a flowchart illustrating an example of an operation of a UE transmitting HARQ-ACK based on downlink information having different formats according to an embodiment of the disclosure.

[0056] Figure 24 FIG. 8 is a flowchart illustrating an example of an operation of a base station receiving HARQ-ACK based on downlink information having different formats according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0057] The terms used in the specification are adopted by considering the functions in the invention as much as possible, but can be changed according to the intention of those skilled in the art, customs, and the appearance of new technologies. In addition, in a specific case, there are terms arbitrarily selected by the applicant, and in this case, the meaning will be described in the corresponding description part of the invention. Therefore, it is intended that the terms used in the specification should not be analyzed only based on the name of the term, but should be analyzed based on the substantial meaning of the terms and the context in the entire specification.

[0058] Throughout the specification and subsequent claims, when it is described that one element is "connected" to another element, the one element can be "directly connected" to the other element or "electrically connected" to the other element through a third element. In addition, unless explicitly described to the contrary, the word "comprise" will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Furthermore, in some example embodiments, a limitation such as "greater than or equal to" or "less than or equal to" based on a specific threshold value can be appropriately replaced with "greater than" or "less than", respectively.

[0059] The following techniques can be used in various wireless access systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier-FDMA (SC-FDMA), etc. The CDMA can be implemented by wireless technology such as universal terrestrial radio access (UTRA) or CDMA2000. The TDMA can be implemented by wireless technology such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). The OFDMA can be implemented by wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), etc. The UTRA is a part of a universal mobile telecommunications system (UMTS). A 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of an evolved UMTS (E-UMTS) using evolved UMTS terrestrial radio access (E-UTRA) and LTE-advanced (A) is an evolved version of the 3GPP LTE. The 3GPP new radio (NR) is a system designed separately from the LTE / LTE-A, and is a system for supporting enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine type communication (mMTC) services as requirements of IMT-2020. For clarity, the 3GPP NR is mainly described, but the technical idea of the present application is not limited thereto.

[0060] Unless otherwise specified in the present specification, a base station can refer to a next-generation node B (gNB) defined in the 3GPP NR. Also, unless otherwise specified, a terminal can refer to a user equipment (UE). Although the detailed embodiments are classified into embodiments to help understanding, the embodiments can be used in combination. In the present disclosure, the configuration of a user equipment can mean a configuration by a base station. In detail, the base station can transmit a signal to the user equipment to set a parameter value used in the operation of the user equipment or a wireless communication system.

[0061] Figure 1 FIG. illustrates an example of a radio frame structure used in a wireless communication system.

[0062] Reference Figure 1 A radio frame (or radio frame) used in the 3GPP NR system can have a length of 10 ms (Δf max N f / 100)*T c ) and include 10 subframes (SFs) of equal size. Here, Δf max = 480*10 3 Hz, Nf = 4096, T c = 1 / (Δf ref *N f,ref ), Δf ref = 15*10 3 Hz, and N f,ref = 2048. Numbers from 0 to 9 can be respectively assigned to 10 subframes within one radio frame. The length of each subframe is 1 ms and can include one or more slots according to the subcarrier spacing. More specifically, in the 3GPP NR system, the subcarrier spacing that can be used is 15*2 μ kHz, and μ can have values of μ = 0 ~ 4 as the subcarrier spacing configuration. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz can be used for the subcarrier spacing. One subframe of 1 ms in length can include 2 μ slots. In this case, the length of each slot is 2 -μ ms. Numbers from 0 to 2 μ -1 can be respectively assigned to 2 μ slots within one subframe. Also, numbers from 0 to 10*2 μ -1 can be respectively assigned to slots within one radio frame. The time resources can be distinguished by at least one of the radio frame number (also referred to as the radio frame index), the subframe number (also referred to as the subframe index), and the slot number (or slot index).

[0063] Figure 2 An example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system is illustrated. In particular, Figure 2 the structure of a resource grid of a 3GPP NR system is shown.

[0064] There is one resource grid per antenna port. Referring to Figure 2 , a slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. One OFDM symbol also refers to one symbol interval. Unless otherwise specified, the OFDM symbol can be simply referred to as a symbol. One RB includes 12 consecutive subcarriers in the frequency domain. Referring to Figure 2 , a signal transmitted per slot can be represented by a resource grid including N size,μ grid,x *N RB sc subcarriers and N slot symb OFDM symbols. Here, x = DL when the signal is a DL signal, and x = UL when the signal is an UL signal. N size,μ grid,xdenotes the number of resource blocks (RBs) according to the subcarrier spacing component p (x is DL or UL), and N slot symb denotes the number of OFDM symbols in a slot. N RB sc is the number of subcarriers that constitute one RB and N RB sc = 12. The OFDM symbols can be referred to as cyclic-shifted OFDM (CP-OFDM) symbols or discrete Fourier transform-spread OFDM (DFT-s-OFDM) symbols according to the multiple access scheme.

[0065] The number of OFDM symbols included in one slot can vary according to the length of a cyclic prefix (CP). For example, one slot includes 14 OFDM symbols in the case of a normal CP, but one slot can include 12 OFDM symbols in the case of an extended CP. In certain embodiments, the extended CP can only be used with a 60 kHz subcarrier spacing. In Figure 2 , one slot is configured with 14 OFDM symbols for ease of description as an example, but embodiments of the disclosure can be applied to a slot having a different number of OFDM symbols in a similar manner. Referring to Figure 2 , each OFDM symbol includes N size,μ grid,x * N RB sc subcarriers in the frequency domain. The types of subcarriers can be divided into data subcarriers for data transmission, reference signal subcarriers for transmission of a reference signal, and a guard band. The carrier frequency is also referred to as a center frequency (fc).

[0066] One RB can be defined by N RB sc (e.g., 12) consecutive subcarriers in the frequency domain. For reference, a resource configured with one OFDM symbol and one subcarrier can be referred to as a resource element (RE) or a tone. Accordingly, one RB can be configured with N slot symb * N RB sc resource elements. Each resource element in the resource grid can be uniquely defined by a pair of indices (k, l) in one slot. k can be an index assigned from 0 to N size,μ grid,x * N RB sc - 1 in the frequency domain, and l can be an index assigned from 0 to N slot symb - 1 in the time domain.

[0067] To let the UE receive a signal from or transmit a signal to the base station, the time / frequency of the UE can be synchronized with that of the base station. This is because when the base station and the UE are synchronized, the UE is able to determine the time and frequency parameters necessary to demodulate a DL signal at the right time and transmit a UL signal.

[0068] Each symbol of a radio frame used in time division duplex (TDD) or unpaired spectrum can be configured with at least one of a DL symbol, a UL symbol, and a flexible symbol. A radio frame used as a DL carrier in frequency division duplex (FDD) or paired spectrum can be configured with a DL symbol or a flexible symbol, and a radio frame used as a UL carrier can be configured with a UL symbol or a flexible symbol. In a DL symbol, a DL transmission is possible, but a UL transmission is not possible. In a UL symbol, a UL transmission is possible, but a DL transmission is not possible. The flexible symbol can be determined to be used as a DL or a UL according to a signal.

[0069] Information on the type of each symbol, i.e., information indicating any one of a DL symbol, a UL symbol, and a flexible symbol, can be configured with a cell-specific or common radio resource control (RRC) signal. In addition, the information on the type of each symbol can be additionally configured with a UE-specific or dedicated RRC signal. The base station signals i) a period of a cell-specific slot configuration, ii) a number of slots having only DL symbols from the beginning of the period of the cell-specific slot configuration, iii) a number of DL symbols from the first symbol of a slot immediately after the slot having only DL symbols, iv) a number of slots having only UL symbols from the end of the period of the cell-specific slot configuration, and v) a number of UL symbols from the last symbol of a slot immediately before the slot having only UL symbols, by using the cell-specific RRC signal. Here, a symbol not configured with any one of a UL symbol and a DL symbol is a flexible symbol.

[0070] When the information on the symbol type is configured with the UE-specific RRC signal, the base station can signal whether a flexible symbol is a DL symbol or a UL symbol with the cell-specific RRC signal. In this case, the UE-specific RRC signal cannot change a DL symbol or a UL symbol configured with the cell-specific RRC signal into another symbol type. The UE-specific RRC signal can signal a number of DL symbols among N slot symb symbols of a corresponding slot per slot and a number of UL symbols among N slot symbthe number of UL symbols among the symbols. In this case, the DL symbols of the slot can be consecutively configured with the first symbol to the i-th symbol of the slot. Also, the UL symbols of the slot can be consecutively configured with the j-th symbol to the last symbol of the slot (where i < j). In the slot, the symbol which is not configured with any one of the UL symbols and the DL symbols is a flexible symbol.

[0071] Figure 3 is a diagram for explaining a physical channel used in a 3GPP system (e.g., NR) and a typical signal transmission method using the physical channel.

[0072] If the power of the UE is turned on or the UE camps on a new cell, the UE performs an initial cell search (S101). Specifically, the UE can be synchronized with the BS in the initial cell search. To this end, the UE can receive a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to be synchronized with the base station and obtain information such as a cell ID. Thereafter, the UE can receive a physical broadcast channel from the base station and obtain broadcast information in the cell.

[0073] Upon completion of the initial cell search, the UE receives a physical downlink shared channel (PDSCH) according to a physical downlink control channel (PDCCH) and information in the PDCCH, so that the UE can obtain more specific system information than system information obtained through the initial cell search (S102). Here, the system information received by the user equipment is cell common system information for normal operation of the user equipment in a physical layer in a radio resource control (RRC) and is referred to as remaining system information or system information block (SIB) 1.

[0074] When the UE initially accesses the base station or does not have a radio resource for signal transmission, the UE can perform a random access procedure on the base station (operations S103 to S106). First, the UE can transmit a preamble through a physical random access channel (PRACH) (S103) and receive a response message for the preamble from the base station through a PDCCH and a corresponding PDSCH (S104). When the UE receives a valid random access response message, the UE transmits data including an identifier of the UE or the like to the base station through a physical uplink shared channel (PUSCH) indicated by a UL grant transmitted from the base station through the PDCCH (S105). Next, the UE waits for reception of a PDCCH as an indication of the base station for collision resolution. If the UE successfully receives the PDCCH through the identifier of the UE (S106), the random access procedure is terminated. The user equipment can obtain terminal-specific system information required for the user equipment to correctly operate in the physical layer in the RRC layer during the random access procedure. When the user equipment obtains the terminal-specific system information from the RRC layer, the user equipment enters an RRC connected mode.

[0075] The RRC layer is used to generate or manage messages between the user equipment and the radio access network (RAN). In more detail, the base station and the user equipment can perform, in the RRC layer, cell system information required for all user equipments in a broadcast cell, management of transmission of a paging message, mobility management and handover, measurement report and control thereof of the user equipment, and storage management including user equipment capability management and device management. In general, since an update of a signal (hereinafter, an RRC signal) transmitted in the RRC layer is longer than a transmission / reception period (i.e., a transmission time interval (TTI)) in the physical layer, the RRC signal can be maintained for a long period and not changed.

[0076] After the above-described procedure, the UE receives a PDCCH / PDSCH (S107) and transmits a physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) (S108) as a general UL / DL signal transmission procedure. In particular, the UE can receive a downlink control information (DCI) through the PDCCH. The DCI can include control information such as resource allocation information for the UE. In addition, the format of the DCI can vary according to a predetermined use. The uplink control information (UCI) transmitted by the UE to the base station through the UL includes a DL / UL ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), a rank indicator (RI), etc. Here, the CQI, the PMI, and the RI can be included in channel state information (CSI). In the 3GPP NR system, the UE can transmit control information such as the HARQ-ACK and the CSI described above through the PUSCH and / or the PUCCH.

[0077] Figure 4 The SS / PBCH block is illustrated for initial cell access in the 3GPP NR system.

[0078] When the power is turned on or access to a new cell is desired, the UE can obtain time and frequency synchronization with the cell and perform an initial cell search procedure. The UE can detect a physical cell identity N cell ID To this end, the UE can receive a synchronization signal, for example, a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), from the base station and synchronize with the base station. In this case, the UE is able to obtain information such as a cell identity (ID).

[0079] Reference Figure 4Referring to FIG. 1, a base station 100 can transmit a synchronization signal (SS) to a UE 200. The synchronization signal can be classified into a PSS and an SSS. The PSS can be used to obtain time-domain and / or frequency-domain synchronization, such as OFDM symbol synchronization and slot synchronization. The SSS can be used to obtain frame synchronization and a cell group ID. Referring to FIG. 2, the PSS can be transmitted in the first OFDM symbol of the SS / PBCH block, and the SSS can be transmitted in the third OFDM symbol of the SS / PBCH block. Figure 4 Referring to (a) of FIG. 3 and Table 2, the SS / PBCH block can be configured with 20 consecutive RBs (= 240 subcarriers) on the frequency axis, and can be configured with 4 consecutive OFDM symbols on the time axis. In this case, in the SS / PBCH block, the PSS is transmitted in the first OFDM symbol through the 56th to 182nd subcarriers, and the SSS is transmitted in the third OFDM symbol. Here, the lowest subcarrier index of the SS / PBCH block is numbered from 0. In the first OFDM symbol in which the PSS is transmitted, the base station does not transmit a signal through the remaining subcarriers, that is, the 0th to 55th subcarriers and the 183rd to 239th subcarriers. Also, in the third OFDM symbol in which the SSS is transmitted, the base station does not transmit a signal through the 48th to 55th subcarriers and the 183rd to 191st subcarriers. The base station transmits a physical broadcast channel (PBCH) through the remaining REs other than the above signals in the SS / PBCH block.

[0080] [Table 1]

[0081]

[0082] The SS allows a total of 1008 unique physical layer cell IDs to be grouped into 336 physical layer cell identifier groups, each including three unique identifiers, specifically, such that each physical layer cell ID will be only a part of one physical layer cell identifier group, by the combination of three PSS and SSS. Thus, the physical layer cell ID N cell ID = 3N (1) ID + N (2) ID can be uniquely defined by an index N (1) ID indicating a range from 0 to 335 of the physical layer cell identifier group, and an index N (2) ID indicating a range from 0 to 2 of the physical layer identifier in the physical layer cell identifier group. The UE can detect the PSS and identify one of the three unique physical layer identifiers. Also, the UE can detect the SSS and identify one of the 336 physical layer cell IDs associated with the physical layer identifier. In this case, the sequence d PSS (n) of the PSS is as follows.

[0083] d PSS (n) = 1 - 2x(m)

[0084]

[0085] 0≤n<127

[0086] Here, x(i+7) = (x(i+4) + x(i)) mod 2 and is given as

[0087] [x(6) x(5) x(4) x(3) x(2) x(1) x(0)] = [1 1 1 0 1 1 0]

[0088] In addition, the sequence d SSS (n) of the SSS is given as follows.

[0089] d SSS (n) = [1 - 2x0((n + m0) mod 127)] [1 - 2x1((n + m1) mod 127)]

[0090]

[0091]

[0092] 0≤n<127

[0093] Here, and is given as

[0094] [x0(6) x0(5) x0(4) x0(3) x0(2) x0(1) x0(0)] = [0 0 0 0 0 0 1]

[0095] [x1(6) x1(5) x1(4) x1(3) x1(2) x1(1) x1(0)] = [0 0 0 0 0 0 1]

[0096] A radio frame having a length of 10 ms can be divided into two half-frames having a length of 5 ms. Referring to FIG. 2, a radio frame is divided into two half-frames, and each half-frame is divided into multiple subframes. Each subframe includes a plurality of resource blocks. Figure 4of (b), a slot in which the SS / PBCH block is transmitted in each half frame will be described. The slot in which the SS / PBCH block is transmitted can be any one of cases A, B, C, D, and E. In case A, the subcarrier spacing is 15 kHz and the starting time point of the SS / PBCH block is the (2, 8 + 14*n)th symbol. In this case, n = 0 or 1 at a carrier frequency of 3 GHz or less. Also, n = 0, 1, 2, 3 can be at a carrier frequency higher than 3 GHz and lower than 6 GHz. In case B, the subcarrier spacing is 30 kHz and the starting time point of the SS / PBCH block is {4, 8, 16, 20} + 28*n. In this case, n = 0 at a carrier frequency of 3 GHz or less. Also, n = 0, 1 can be at a carrier frequency higher than 3 GHz and lower than 6 GHz. In case C, the subcarrier spacing is 30 kHz and the starting time point of the SS / PBCH block is the (2, 8 + 14*n)th symbol. In this case, n = 0 or 1 at a carrier frequency of 3 GHz or less. Also, n = 0, 1, 2, 3 can be at a carrier frequency higher than 3 GHz and lower than 6 GHz. In case D, the subcarrier spacing is 120 kHz and the starting time point of the SS / PBCH block is the (4, 8, 16, 20 + 28*n)th symbol. In this case, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18 at a carrier frequency of 6 GHz or more. In case E, the subcarrier spacing is 240 kHz and the starting time point of the SS / PBCH block is the (8, 12, 16, 20, 32, 36, 40, 44 + 56*n)th symbol. In this case, n = 0, 1, 2, 3, 5, 6, 7, 8 at a carrier frequency of 6 GHz or more.

[0097] Figure 5 A procedure of transmitting control information and a control channel in a 3GPP NR system is illustrated. Referring to Figure 5(a), the base station can add a cyclic redundancy check (CRC) masked (e.g., exclusive-OR operation) with a radio network temporary identifier (RNTI) to control information (e.g., downlink control information (DCI)) (S202). The base station can scramble the CRC with an RNTI value determined according to a purpose / target of each control information. A common RNTI used by one or more UEs can include at least one of a system information RNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI), and a transmit power control RNTI (TPC-RNTI). Also, a UE-specific RNTI can include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, the base station can perform rate matching according to a resource amount for PDCCH transmission after performing channel coding (e.g., polar coding) (S204). Thereafter, the base station can multiplex the DCI based on a PDCCH structure on a control channel element (CCE) basis (S208). Also, the base station can apply additional procedures such as scrambling, modulation (e.g., QPSK), interleaving, etc. to the multiplexed DCI (S210), and then map the DCI to a resource to be transmitted. The CCE is a basic resource unit for the PDCCH, and one CCE can include a plurality of (e.g., six) resource element groups (REGs). One REG can be configured with a plurality of (e.g., 12) REs. The number of CCEs used for one PDCCH can be defined as an aggregation level. In the 3GPP NR system, aggregation levels of 1, 2, 4, 8, or 16 can be used. Figure 5 (b) is a diagram related to a CCE aggregation level and multiplexing of a PDCCH, and illustrates a type of a CCE aggregation level for one PDCCH and CCEs transmitted in a control region therefrom.

[0098] Figure 6 A control resource set (CORESET) in which a physical downlink control channel (PUCCH) can be transmitted in a 3GPP NR system is illustrated.

[0099] A CORESET is a time-frequency resource in which a PDCCH (i.e., a control signal for a UE) is transmitted. Further, a search space to be described later can be mapped to one CORESET. Accordingly, a UE can monitor a time-frequency domain designated as a CORESET instead of monitoring all frequency bands for PDCCH reception, and decode a PDCCH mapped to the CORESET. A base station can configure one or more CORESETs to a UE per cell. A CORESET can be configured with up to three consecutive symbols on a time axis. Further, a CORESET can be configured in units of six consecutive PRBs on a frequency axis. In Figure 5 In an embodiment, CORESET #1 is configured with consecutive PRBs, and CORESET #2 and CORESET #3 are configured with non-consecutive PRBs. A CORESET can be located in any symbol in a slot. For example, in an embodiment, Figure 5 In an embodiment, CORESET #1 starts from the first symbol of a slot, CORESET #2 starts from the fifth symbol of a slot, and CORESET #9 starts from the ninth symbol of a slot.

[0100] Figure 7 A method for setting a PDCCH search space in a 3GPP NR system is illustrated.

[0101] In order to transmit a PDCCH to a UE, each CORESET can have at least one search space. In an embodiment of the disclosure, a search space is a set of all time-frequency resources (hereinafter, a PDCCH candidate) that can be used to transmit a PDCCH of a UE. A search space can include a common search space that requires a 3GPP NR UE to search in common and a terminal-specific search space or a UE-specific search space that requires a specific UE to search. In a common search space, a UE can monitor a PDCCH set so that all UEs in a cell belonging to the same base station search in common. Further, a UE-specific search space can be set for each UE so that a UE monitors a PDCCH allocated to each UE at a search space location that is different according to the UE. In the case of a UE-specific search space, search spaces between UEs can be partially overlapped and allocated due to a limited control region in which a PDCCH can be allocated. Monitoring a PDCCH includes blind decoding a PDCCH candidate in a search space. When blind decoding is successful, it can be expressed as (successfully) detecting / receiving a PDCCH, and when blind decoding fails, it can be expressed as not detecting / receiving or not successfully detecting / receiving a PDCCH.

[0102] For convenience of explanation, a PDCCH scrambled with a group common (GC) RNTI known by a UE previously is referred to as a group common (GC) PDCCH or a common PDCCH to transmit DL control information to one or more UEs. Also, a PDCCH scrambled with a specific terminal's RNTI known by a specific UE is referred to as a PDCCH of the specific UE to transmit UL scheduling information or DL scheduling information to the specific UE. The common PDCCH can be included in a common search space, and the UE-specific PDCCH can be included in the common search space or a UE-specific search space.

[0103] The base station can signal information (i.e., a DL grant) about resource allocation of a paging channel (PCH) and a downlink shared channel (DL-SCH) as transport channels or information (i.e., a UL grant) about resource allocation of an uplink shared channel (UL-SCH) and a hybrid automatic repeat request (HARQ) to each UE or a group of UEs through a PDCCH. The base station can transmit a PCH transport block and a DL-SCH transport block through a PDSCH. The base station can transmit data excluding specific control information or specific service data through a PDSCH. Also, the UE can receive data excluding specific control information or specific service data through a PDSCH.

[0104] The base station can include information about to which UE (one or more UEs) PDSCH data is transmitted and how the PDSCH data is to be received and decoded by the corresponding UE in a PDCCH and transmit the PDCCH. For example, it is assumed that a DCI transmitted through a specific PDCCH is CRC-masked with an RNTI 'A' and the DCI indicates that a PDSCH is allocated to a radio resource 'B' (e.g., a frequency location) and indicates transport format information 'C' (e.g., a transport block size, a modulation scheme, coding information, etc.). The UE monitors the PDCCH using RNTI information that the UE has. In this case, if there is a UE that performs blind decoding of the PDCCH using the 'A' RNTI, the UE receives the PDCCH and receives the PDSCH indicated by 'B' and 'C' through the information of the received PDCCH.

[0105] Table 2 shows an embodiment of a physical uplink control channel (PUCCH) used in a wireless communication system.

[0106] [Table 2]

[0107] PUCCH format Length of OFDM symbol Number of bits 0 1-2 ≤2 1 4-14 ≤2 2 1-2 ＞2 3 4-14 ＞2 4 4-14 ＞2

[0108] The PUCCH can be used to transmit the following UL control information (UCI).

[0109] - Scheduling Request (SR): information for requesting UL UL-SCH resources.

[0110] - HARQ-ACK: a response to PDCCH (indicating DL SPS release) and / or a response to a DL transport block (TB) on PDSCH. The HARQ-ACK indicates whether information transmitted on PDCCH or PDSCH is received. The HARQ-ACK response includes a positive ACK (hereinafter, ACK), a negative ACK (hereinafter, NACK), a discontinuous transmission (DTX), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK / NACK and ACK / NACK. In general, ACK can be represented by a bit value of 1, and NACK can be represented by a bit value of 0.

[0111] - Channel State Information (CSI): feedback information about a DL channel. The UE generates it based on a CSI-reference signal (RS) transmitted by the base station. Multiple-input multiple-output (MIMO)-related feedback information includes a rank indicator (RI) and a precoding matrix indicator (PMI). The CSI can be divided into CSI part 1 and CSI part 2 according to information indicated by the CSI.

[0112] In the 3GPP NR system, five PUCCH formats can be used to support various service scenarios, various channel environments, and frame structures.

[0113] PUCCH format 0 is a format capable of transmitting 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 can be transmitted through one or two OFDM symbols on a time axis and one PRB on a frequency axis. When PUCCH format 0 is transmitted through two OFDM symbols, the same sequence on the two symbols can be transmitted through different RBs. Here, the sequence can be a sequence cyclically shifted (CS) from a base sequence used in PUCCH format 0. In this way, the user equipment can obtain a frequency diversity gain. In more detail, the user equipment can determine a cyclic shift (CS) value m bit bits of UCI (M bit = 1 or 2) to 1. cs In addition, a sequence obtained by cyclically shifting a base sequence having a length of 12 based on the determined CS value m cs may be mapped to 12 REs of one OFDM symbol and one RB to be transmitted. When the number of cyclic shifts available to the user equipment is 12 and M bit = 1, 1-bit UCI 0 and 1 can be mapped to two cyclic shift sequences whose cyclic shift values differ by 6, respectively. In addition, when M bitWhen MUCI=2, 2-bit UCI 00, 01, 11, and 10 can be mapped to four cyclic shift sequences whose cyclic shift values differ by 3, respectively.

[0114] PUCCH format 1 can deliver 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 can be transmitted through one PRB on a frequency axis and consecutive OFDM symbols on a time axis. Here, the number of OFDM symbols occupied by PUCCH format 1 can be one of 4 to 14. More specifically, the UE can modulate M bit = 1-bit UCI with BPSK. The UE can modulate M bit = 2-bit UCI with QPSK. The signal is obtained by multiplying the modulated complex-valued symbol d(0) by a length-12 sequence. In this case, the sequence can be a base sequence used for PUCCH format 0. The UE transmits the obtained signal by time-axis orthogonal cover code (OCC) spreading even-numbered OFDM symbols to which PUCCH format 1 is assigned. PUCCH format 1 determines the maximum number of different UEs multiplexed in one RB according to the length of the OCC to be used. A demodulation reference signal (DMRS) can be spread with the OCC and mapped to odd-numbered OFDM symbols of PUCCH format 1.

[0115] PUCCH format 2 can deliver more than 2-bit UCI. PUCCH format 2 can be transmitted through one or two OFDM symbols on a time axis and one or more RBs on a frequency axis. When PUCCH format 2 is transmitted in two OFDM symbols, sequences transmitted in different RBs through the two OFDM symbols can be identical to each other. Here, the sequence can be a plurality of modulated complex-valued symbols d(0),..., d(M symbol-1 ) Here, M symbol may be M bit / 2. Through this, the UE can obtain frequency diversity gain. More specifically, M bit -bit UCI (M bit > 2) is bit-level scrambled, QPSK-modulated, and mapped to the RB of one or two OFDM symbols. Here, the number of RBs can be one of 1 to 16.

[0116] PUCCH format 3 or PUCCH format 4 can deliver more than 2-bit UCI. PUCCH format 3 or PUCCH format 4 can be transmitted through consecutive OFDM symbols on a time axis and one PRB on a frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 can be one of 4 to 14. Specifically, the UE modulates Mbit one bit UCI (M bit ) is modulated to generate complex-valued symbols d(0) to d(M symb-1 ). Here, when π / 2-BPSK is used, M symb = M bit , and when QPSK is used, M symb = M bit / 2. The UE can not apply block-wise spreading for PUCCH format 3. However, the UE can apply block-wise spreading for one RB (i.e., 12 subcarriers) using PreDFT-OCC of length 12, so that PUCCH format 4 can have two or four multiplexing capability. The UE performs transmit precoding (or DFT precoding) on the spread signal and maps it to each RE to transmit the spread signal.

[0117] In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 can be determined according to the length of UCI transmitted by the UE and the maximum coding rate. When the UE uses PUCCH format 2, the UE can transmit HARQ-ACK information and CSI information together through the PUCCH. When the number of RBs that the UE can transmit is greater than the maximum number of RBs that PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the UE can transmit only the remaining UCI information according to the priority of the UCI information without transmitting some UCI information.

[0118] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured by an RRC signal to indicate frequency hopping in a slot. When frequency hopping is configured, the index of the RB to be frequency-hopped can be configured by an RRC signal. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted through N OFDM symbols in the time axis, the first hop can have floor(N / 2) OFDM symbols and the second hop can have ceiling(N / 2) OFDM symbols.

[0119] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured to be repeatedly transmitted in multiple slots. In this case, the number K of slots in which the PUCCH is repeatedly transmitted can be configured by an RRC signal. The repeatedly transmitted PUCCH must start from the OFDM symbol at a constant position in each slot and have a constant length. When one of the OFDM symbols among the OFDM symbols of the slot in which the UE should transmit the PUCCH is indicated as a DL symbol by an RRC signal, the UE can not transmit the PUCCH in the corresponding slot and delay the transmission of the PUCCH to the next slot to transmit the PUCCH.

[0120] Meanwhile, in the 3GPP NR system, a user equipment can perform transmission / reception using a bandwidth smaller than or equal to the bandwidth of a carrier (or cell). To this end, the user can receive a configuration of a bandwidth part (BWP) configured with a partial continuous bandwidth in the carrier bandwidth. A user equipment operating according to a TDD or in an unpaired spectrum can receive a configuration of up to four pairs of DL / UL BWPs in one carrier (or cell). Also, the user equipment can activate one pair of DL / UL BWPs. A user equipment operating according to an FDD or in a paired spectrum can receive up to four DL BWPs in a downlink carrier (or cell) and up to four UL BWPs in an uplink carrier (or cell). The user equipment can activate one DL BWP and one UL BWP per carrier (or cell). The user equipment can not receive or transmit in time-frequency resources other than the activated BWP. The activated BWP can be referred to as an active BWP.

[0121] A base station can indicate an activated BWP among the BWPs configured for a user equipment through downlink control information (DCI). The BWP indicated through the DCI is activated, and the other configured BWPs are deactivated. In a carrier (or cell) operating according to a TDD, the base station can add a bandwidth part indicator (BPI) indicating a BWP to be activated to DCI scheduling a PDSCH or a PUSCH to change a pair of DL / UL BWPs of the user equipment. The user equipment can receive the DCI scheduling the PDSCH or the PUSCH and can identify a pair of DL / UL BWPs activated based on the BPI. In the case of a downlink carrier (or cell) operating according to an FDD, the base station can add a BPI indicating a BWP to be activated to DCI scheduling a PDSCH to change a DL BWP of the base station. In the case of an uplink carrier (or cell) operating according to an FDD, the base station can add a BPI indicating a BWP to be activated to DCI scheduling a PUSCH to change a UL BWP of the base station.

[0122] Figure 8 is a conceptual diagram illustrating carrier aggregation.

[0123] Carrier aggregation is a method in which a UE uses a plurality of frequency blocks or (logically) cells configured with UL resources (or component carriers) and / or DL resources (or component carriers) as one large logical frequency band so that a wireless communication system uses a wider frequency band. One component carrier can also be referred to as a term called a primary cell (PCell) or a secondary cell (SCell) or a primary SCell (PScell). However, hereinafter, for convenience of description, the term "component carrier" is used.

[0124] Reference Figure 8As an example of the 3GPP NR system, the entire system band can include a maximum of 16 component carriers, and each component carrier can have a bandwidth of a maximum of 400 MHz. A component carrier can include one or more physically contiguous subcarriers. Although it is shown in Figure 8 that each component carrier has the same bandwidth, this is merely an example, and each component carrier can have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other in the frequency axis, the drawing is shown in a logical concept, and each component carrier can be physically adjacent to each other, or can be spaced apart.

[0125] A different center frequency can be used for each component carrier. In addition, one common center frequency can be used in physically adjacent component carriers. Assuming that all component carriers are physically adjacent in the embodiment of Figure 8 , center frequency A can be used in all component carriers. In addition, assuming that respective component carriers are not physically adjacent to each other, center frequency A and center frequency B can be used in each component carrier.

[0126] When the total system band is extended by carrier aggregation, a frequency band for communication with each UE can be defined in units of component carriers. UE A can use 100 MHz as the total system band, and perform communication using all five component carriers. UEs B1 to B5 can perform communication using only a 20 MHz bandwidth and using one component carrier. UEs C1 and C2 can perform communication using a 40 MHz bandwidth and using two component carriers, respectively. The two component carriers can be logically / physically adjacent or not adjacent. UE C1 represents a case of using two non-adjacent component carriers, and UE C2 represents a case of using two adjacent component carriers.

[0127] Figure 9 are diagrams for explaining single carrier communication and multi-carrier communication. In particular, Figure 9 (a) shows a single carrier subframe structure and Figure 9 (b) shows a multi-carrier subframe structure.

[0128] Referring to Figure 9 (a), in an FDD mode, a general wireless communication system can perform data transmission or reception through one DL band and one UL band corresponding thereto. In another specific embodiment, in a TDD mode, a wireless communication system can divide a radio frame into UL time units and DL time units in the time domain, and perform data transmission or reception through the UL / DL time units. Referring to Figure 9(b), which enables aggregation of three 20MHz component carriers (CCs) into each of UL and DL, enabling support of 60MHz bandwidth. Each CC can be adjacent or non-adjacent to each other in the frequency domain. Figure 9 (b) shows a case where the bandwidth of UL CCs and the bandwidth of DL CCs are the same and symmetric, but the bandwidth of each CC can be determined independently. In addition, asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is possible. A DL / UL CC allocated / configured to a specific UE through RRC can be referred to as a serving DL / UL CC of the specific UE.

[0129] A base station can perform communication with a UE by activating some or all of the serving CCs of the UE or deactivating some of the CCs. The base station can change the CCs to be activated / deactivated and change the number of CCs to be activated / deactivated. If the base station allocates CCs available for a UE as cell-specific or UE-specific, at least one of the allocated CCs is not deactivated unless the CC allocation for the UE is completely reconfigured or the UE is handed over. One CC that is not deactivated by the UE is referred to as a primary CC (PCC) or a primary cell (PCell), and a CC that the base station can freely activate / deactivate is referred to as a secondary CC (SCC) or a secondary cell (SCell).

[0130] Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of DL resources and UL resources, i.e., a combination of DL CCs and UL CCs. A cell can be configured with DL resources only or with a combination of DL resources and UL resources. When carrier aggregation is supported, the linkage between the carrier frequency of the DL resources (or DL CCs) and the carrier frequency of the UL resources (or UL CCs) can be indicated by system information. The carrier frequency refers to the center frequency of each cell or CC. A cell corresponding to a PCC is referred to as a PCell, and a cell corresponding to an SCC is referred to as an SCell. The carrier corresponding to the PCell in the DL is a DL PCC, and the carrier corresponding to the PCell in the UL is a UL PCC. Similarly, the carrier corresponding to the SCell in the DL is a DL SCC, and the carrier corresponding to the SCell in the UL is a UL SCC. According to the UE capability, a serving cell can be configured with one PCell and zero or more SCells. In the case of a UE in an RRC_CONNECTED state but not configured for carrier aggregation or not supporting carrier aggregation, only one serving cell is configured with a PCell only.

[0131] As described above, the term "cell" used in carrier aggregation is distinguished from the term "cell" indicating a certain geographical area provided with a communication service by one base station or one antenna group. That is, one component carrier can also be referred to as a scheduling cell, a scheduled cell, a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, in order to distinguish the cell indicating a certain geographical area and the cell of carrier aggregation, in the present disclosure, the cell of carrier aggregation is referred to as a CC, and the cell of a geographical area is referred to as a cell.

[0132] Figure 10 is a diagram illustrating an example in which a cross-carrier scheduling technique is applied. When cross-carrier scheduling is set, a control channel transmitted through a first CC can schedule a data channel transmitted through the first CC or a second CC using a carrier indicator field (CIF). The CIF is included in DCI. In other words, a scheduling cell is set, and a DL grant / UL grant transmitted in a PDCCH region of the scheduling cell schedules a PDSCH / PUSCH of a scheduled cell. That is, there is a search region for a plurality of component carriers in the PDCCH region of the scheduling cell. The PCell can basically be the scheduling cell, and a specific SCell can be designated as the scheduling cell by an upper layer.

[0133] In Figure 10 In an embodiment of, it is assumed that three DL CCs are merged. Here, it is assumed that a DL component carrier #0 is a DL PCC (or a PCell), and a DL component carrier #1 and a DL component carrier #2 are DL SCCs (or SCells). Further, it is assumed that the DL PCC is set as a PDCCH monitoring CC. When cross-carrier scheduling is not configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, the CIF is disabled, and each DL CC is able to transmit only a PDCCH for scheduling its PDSCH according to the NR PDCCH rule without the CIF (non-cross-carrier scheduling, self-carrier scheduling). Meanwhile, if cross-carrier scheduling is configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, the CIF is enabled, and a specific CC (for example, a DL PCC) can use the CIF to transmit not only a PDCCH for scheduling a PDSCH of a DL CC A but also a PDCCH for scheduling a PDSCH of another CC (cross-carrier scheduling). On the other hand, a PDCCH is not transmitted in another DL CC. Accordingly, the UE monitors a PDCCH not including the CIF to receive a self-carrier scheduled PDSCH according to whether cross-carrier scheduling is configured for the UE, or monitors a PDCCH including the CIF to receive a cross-carrier scheduled PDSCH.

[0134] On the other hand, Figure 9 andFigure 10 FIG. 3GPP LTE-A system is illustrated, and the same or similar configuration can be applied to the 3GPP NR system. However, in the 3GPP NR system, Figure 9 and Figure 10 a subframe can be replaced with a slot.

[0135] Figure 11 is a block diagram illustrating a configuration of a UE and a base station according to an embodiment of the disclosure. In an embodiment of the disclosure, the UE can be implemented with various types of wireless communication devices or computing devices that are guaranteed to be portable and mobile. The UE can be referred to as a user equipment (UE), a station (STA), a mobile subscriber (MS), etc. Further, in an embodiment of the disclosure, the base station controls and manages a cell (e.g., a macro cell, a femto cell, a pico cell, etc.) corresponding to a service area, and performs functions of signal transmission, channel designation, channel monitoring, self-diagnosis, relaying, etc. The base station can be referred to as a next-generation node B (gNB) or an access point (AP).

[0136] As illustrated in the drawings, the UE 100 according to an embodiment of the disclosure can include a processor 110, a communication module 120, a memory 130, a user interface 140, and a display unit 150.

[0137] First, the processor 110 can execute various instructions or processes within the UE 100 and process data. Further, the processor 110 can control the entire operation of each unit including the UE 100, and can control transmission / reception of data between the units. Here, the processor 110 can be configured to perform operations according to the embodiments described in the disclosure. For example, the processor 110 can receive slot configuration information, determine a slot configuration based on the slot configuration information, and perform communication according to the determined slot configuration.

[0138] Next, the communication module 120 can be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 120 can include a plurality of network interface cards (NICs), such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123, in an internal or external form. In the drawings, the communication module 120 is illustrated as an integrated module as a whole, but each network interface card can be independently arranged according to a circuit configuration or usage, unlike the drawings.

[0139] The cellular communication interface card 121 can transmit or receive radio signals with at least one of the base station 200, the external device, and the server by using a mobile communication network and provide a cellular communication service in a first frequency band based on an instruction from the processor 110. According to an embodiment, the cellular communication interface card 121 can include at least one NIC module using a frequency band less than 6 GHz. The at least one NIC module of the cellular communication interface card 121 can independently perform cellular communication with at least one of the base station 200, the external device, and the server in a sub-6 GHz band supported by the corresponding NIC module in compliance with a cellular communication standard or protocol.

[0140] The cellular communication interface card 122 can transmit or receive radio signals with at least one of the base station 200, the external device, and the server by using a mobile communication network and provide a cellular communication service in a second frequency band based on an instruction from the processor 110. According to an embodiment, the cellular communication interface card 122 can include at least one NIC module using a frequency band greater than 6 GHz. The at least one NIC module of the cellular communication interface card 122 can independently perform cellular communication with at least one of the base station 200, the external device, and the server in a above-6 GHz band supported by the corresponding NIC module in compliance with a cellular communication standard or protocol.

[0141] The unlicensed band communication interface card 123 transmits or receives radio signals with at least one of the base station 200, the external device, and the server by using a third frequency band that is an unlicensed band and provides an unlicensed band communication service based on an instruction from the processor 110. The unlicensed band communication interface card 123 can include at least one NIC module using an unlicensed band. For example, the unlicensed band can be a 2.4 GHz or 5 GHz frequency band. The at least one NIC module of the unlicensed band communication interface card 123 can independently or dependently perform wireless communication with at least one of the base station 200, the external device, and the server according to an unlicensed band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0142] The memory 130 stores control programs used in the UE 100 and various data used therefor. Such control programs can include prescribed programs needed to perform wireless communication with at least one of the base station 200, the external device, and the server.

[0143] Next, the user interface 140 includes various input / output means provided in the UE 100. In other words, the user interface 140 can receive a user input using various input means, and the processor 110 can control the UE 100 based on the received user input. Furthermore, the user interface 140 can perform output based on an instruction from the processor 110 using various output means.

[0144] Next, the display unit 150 outputs various images on the display screen. The display unit 150 can output various display objects, such as content or a user interface executed by the processor 110, based on a control instruction from the processor 110.

[0145] In addition, the base station 200 according to an embodiment of the disclosure can include a processor 210, a communication module 220, and a memory 230.

[0146] First, the processor 210 can execute various instructions or programs and process internal data of the base station 200. In addition, the processor 210 can control the entire operation of each unit in the base station 200 and control the transmission and reception of data between the units. Here, the processor 210 can be configured to perform operations according to the embodiments described in the disclosure. For example, the processor 210 can signal a slot configuration and perform communication according to the signaled slot configuration.

[0147] Next, the communication module 220 can be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 120 can include a plurality of network interface cards, such as cellular communication interface cards 221 and 222 and an unlicensed band communication interface card 223, in an internal or external form. In the drawing, the communication module 220 is shown as an integrated module as a whole, but unlike the drawing, each network interface card can be independently arranged according to a circuit configuration or usage.

[0148] The cellular communication interface card 221 can transmit or receive radio signals with at least one of the base station 100, an external device, and a server by using a mobile communication network and provide a cellular communication service in a first frequency band based on an instruction from the processor 210. According to an embodiment, the cellular communication interface card 221 can include at least one NIC module that uses a frequency band less than 6 GHz. The at least one NIC module of the cellular communication interface card 221 can independently perform cellular communication with at least one of the base station 100, the external device, and the server in a frequency band less than 6 GHz supported by the corresponding NIC module in accordance with a cellular communication standard or protocol.

[0149] The cellular communication interface card 222 can transmit or receive radio signals with at least one of the base station 100, the external device, and the server by using a mobile communication network and provide a cellular communication service in a second frequency band based on an instruction from the processor 210. According to an embodiment, the cellular communication interface card 222 can include at least one NIC module using a frequency band of 6 GHz or more. The at least one NIC module of the cellular communication interface card 222 can independently perform cellular communication with at least one of the base station 100, the external device, and the server in a frequency band of 6 GHz or more supported by the corresponding NIC module in compliance with a cellular communication standard or protocol.

[0150] The unlicensed band communication interface card 223 transmits or receives radio signals with at least one of the base station 100, the external device, and the server by using a third frequency band that is an unlicensed band and provides an unlicensed band communication service based on an instruction from the processor 210. The unlicensed band communication interface card 223 can include at least one NIC module using an unlicensed band. For example, the unlicensed band can be a frequency band of 2.4 GHz or 5 GHz. The at least one NIC module of the unlicensed band communication interface card 223 can independently or dependently perform wireless communication with at least one of the base station 100, the external device, and the server in compliance with an unlicensed band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0151] Figure 11 FIG. 1 is a block diagram illustrating a UE 100 and a base station 200 according to an embodiment of the disclosure, and the separately illustrated blocks are logically divided elements of the devices. Accordingly, the aforementioned elements of the devices can be mounted in a single chip or a plurality of chips according to the design of the devices. Also, a part of the configuration of the UE 100, e.g., the user interface 140, the display unit 150, etc., can be selectively provided in the UE 100. Also, the user interface 140, the display unit 150, etc. can be additionally provided in the base station 200 if necessary.

[0152] In an NR wireless communication system, a user equipment can transmit a codebook including hybrid automatic repeat request (HARQ)-ACK information to signal whether reception of a downlink signal or channel is successful. The HARQ-ACK codebook includes one or more bits indicating whether reception of a downlink signal or channel is successful. Here, the downlink channel can include at least one of a physical downlink shared channel (PDSCH), a semi-persistent scheduling (SPS) PDSCH, and a PDCCH for releasing the SPS PDSCH. The HARQ-ACK codebook can be divided into a semi-static HARQ-ACK codebook (or a first type codebook) and a dynamic HARQ-ACK codebook (or a second type codebook). A base station can set one of the two HARQ-ACK codebooks for a user equipment. The user equipment can use the HARQ-ACK codebook set for the user equipment.

[0153] When using the semi-static HARQ-ACK codebook, the base station can use an RRC signal to configure the number of bits of the HARQ-ACK codebook and information of each bit of the HARQ-ACK codebook used to determine which downlink signal or channel is successfully received. Thus, the base station does not have to signal the information required to transmit the HARQ-ACK codebook to the user equipment every time the HARQ-ACK codebook needs to be transmitted.

[0154] When the dynamic HARQ-ACK codebook is used, the base station can signal information required to generate the HARQ-ACK codebook through the PDCCH (or DCI). In detail, the base station can signal information required to generate the HARQ-ACK codebook through a downlink assignment index (DAI) field of the PDCCH (or DCI). In certain embodiments, the DAI indicates information about the number of bits of the HARQ-ACK codebook and information about which channel or signal each bit of the HARQ-ACK codebook indicates reception success or failure for. The user equipment can receive the DAI field through the PDCCH (or DCI) for scheduling the PDSCH. The value of the DAI field can be divided into a counter-DAI and a total-DAI. The total-DAI indicates the number of downlink signals or channels, whose reception success or failure is indicated through the HARQ-ACK codebook, until the current monitoring occasion (MO). The counter-DAI indicates the HARQ-ACK codebook bit indicating reception success or failure of the downlink signal or channel among the downlink signals or channels, whose reception success or failure is indicated through the HARQ-ACK codebook, of the current cell until the current monitoring occasion. The PDCCH (or DCI) for scheduling the PDSCH can include the value of the counter-DAI corresponding to the scheduled PDSCH. Also, the PDCCH (or DCI) for scheduling the PDSCH can include the value of the total-DAI corresponding to the scheduled PDSCH. The user equipment can determine the number of bits of the dynamic HARQ-ACK codebook based on the information signaled by the PDCCH (or DCI). In detail, the user equipment can determine the number of bits of the dynamic HARQ-ACK codebook based on the DAI of the PDCCH (or DCI).

[0155] Figure 12 is a flowchart illustrating an example of signaling between a user equipment and a base station to which embodiments of the disclosure are applicable.

[0156] Referring to Figure 12 , the UE receives RRC configuration information from the base station, the RRC configuration information including information for receiving downlink control information (DCI) (S12010).

[0157] For example, the RRC configuration information can include information related to a control resource set (CORESET) and a search space in order for the UE to detect a PDCCH including downlink control information. In this case, the information related to the control resource set can include at least one of an identifier (ID) of a control resource set through which the UE can detect a PDCCH including DCI, control channel element (CCE) configuration information, and control resource set length (duration) or frequency resource information. In this case, the information related to the search space can include at least one of an identifier (ID) of a search space through which the UE can detect a PDCCH including DCI, a format of DCI that can be detected in each search space, a detection duration, or resource information.

[0158] Then, the UE can receive the DCI by detecting the PDCCH in the monitoring occasion based on the RRC configuration information (S12020). The UE can acquire the DCI by detecting the PDCCH in a specific search space of the monitoring occasion according to the type of service and / or data based on the RRC configuration information.

[0159] In this case, the DAI included in the DCI can be configured with different bits according to the format of the DCI. For example, in the DCI format 1_0, the DAI can be configured with 2 bits, and in the DCI format 1_1, the DAI can be configured with 1 bit for a semi-static HARQ-ACK codebook DAI and 2 bits for a dynamic HARQ-ACK codebook DAI.

[0160] Table 3 below shows an example of bits of the DAI according to the DCI format.

[0161] [Table 3]

[0162]

[0163] In addition, resources for reception of a PDSCH or transmission of a PUSCH can be allocated to the UE through a PDCCH (or DCI).

[0164] Then, the UE can receive the PDSCH or transmit the PUSCH to the base station through the allocated resources (S12030). If the UE receives the PDSCH from the base station, the UE can generate a HARQ-ACK codebook indicating ACK / NACK of the received PDSCH based on the DAI value included in the PDCCH (or DCI) for scheduling the PDSCH and transmit the generated HARQ-ACK codebook to the base station by including the generated HARQ-ACK codebook in uplink control information (UCI) (S12040).

[0165] Figure 13An example of a pseudo code based method for counting, by a user equipment, a number of PDSCHs transmitted from a base station is shown that can be applied to embodiments of the present disclosure.

[0166] Figure 13 (a) and (b) of FIG. 1 illustrate 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 by a specific DCI, and a stored total-DAI value.

[0167] In particular, referring to Figure 13 (a) of FIG. 1, the UE can set a counter-DAI value of a PDCCH (or DCI) received in a serving cell c at a monitoring occasion m to set a stored counter-DAI value to V temp , and set a stored total-DAI value to V temp2 In this case, a range T of a value that can be expressed as a number of bits of DAI can be calculated by Equation 1 below D .

[0168] [Equation 1]

[0169]

[0170] Here, a monitoring occasion index m and a cell index c are omitted. Tables 4 and 5 illustrate a range of values of a counter-DAI or a total-DAI expressed in terms of a number of bits of the counter-DAI or a number of bits of the total-DAI. Table 4 illustrates an example when the number of bits of the counter-DAI or the number of bits of the total-DAI is 2 bits, and Table 5 illustrates an example when the number of bits of the counter-DAI or the number of bits of the total-DAI is 1 bit.

[0171] [Table 4]

[0172]

[0173] [Table 5]

[0174]

[0175] In this case, a pseudo code for generating a HARQ-ACK codebook is shown in Table 6 below.

[0176] [Table 6]

[0177]

[0178]

[0179] In this case, using the pseudo code of Table 6, the UE can compare Vtemp and V C-DAI,c,m Value Figure 13 As shown in (a), it is determined whether PDSCH reception is omitted due to a failure in reception of a PDCCH (or DCI) for scheduling PDSCH transmitted from a base station.

[0180] For example, Figure 13 As shown in (a), when the UE receives a 2-bit counter-DAI configuration, the UE can calculate T D =2 2 =4, and it is seen that the range that can be expressed by the number of bits of the counter-DAI is from 1 to 4. When a PDCCH (or DCI) is received, when the value V of the counter-DAI of the PDCCH (or DCI) C-DAI,c,m is "1" and V temp When the value of is "4", it can be recognized that PDSCH is continuously transmitted without loss. However, when a PDCCH (or DCI) is received, when the value of the counter-DAI of the PDCCH (or DCI) is V C-DAI,c,m is "2" and V temp When the value of Counter-DAI is "4", the UE can recognize that the PDSCH scheduled by the PDCCH (or DCI) with the value of Counter-DAI being "1" is lost, and can indicate the HARQ-ACK for the PDSCH as NACK.

[0181] In addition, if Figure 13 As shown in (b), the UE can compare the stored value V temp2 and V temp (these two are the total DAI values ​​stored) to identify the omission of the transmission of PDSCH scheduled by the base station's PDCCH. Figure 13 As shown in (b), when the UE receives a 2-bit total-DCI configuration, calculate T D =2 2 =4, and the range of the total-DAI bits that can be expressed is 1 to 4. When the total-DAI V of the PDCCH (or DCI) last received by the UE temp2 The value is "1" and V temp When the value of is "4", it can be recognized that no PDSCH has been lost since the last received PDCCH. However, when the total-DAI value V of the PDCCH (or DCI) last received by the UE is temp2 is "2" and V temp When the value of is '4', the UE may recognize that a PDSCH scheduled by one PDCCH (or DCI) has been lost since the last received PDCCH and may indicate HARQ-ACK for the PDSCH as NACK.

[0182] In Table 6, the size of the final HARQ-ACK codebook of the UE can be determined by O ACK with the value.

[0183] A new DCI format for providing an ultra-reliable and low latency communication (URLLC) service can be introduced. Such a new DCI format has a feature capable of setting the length of each field of the DCI in order to reduce the bit size. Hereinafter, the newly introduced DCI format will be referred to as DCI format 0_2 and DCI format 1_2.

[0184] The DCI format 0_2 is a DCI format for scheduling a PUSCH, and the DCI format 1_2 is a DCI format for scheduling a PDSCH.

[0185] In addition, in Rel-16 NR, up to two HARQ-ACK codebooks can be generated according to the service type. For example, one HARQ-ACK codebook can be generated by collecting HARQ-ACK information about a PDSCH for an eMBB service, and one HARQ-ACK codebook can be generated by collecting HARQ-ACK information about a PDSCH for a URLLC service. In the DCI formats 1_0, 1_1, and 1_2 for scheduling a PDSCH, it is necessary to indicate in which HARQ-ACK codebook HARQ-ACK information about a scheduled PDSCH is included. In this case, various methods can be used as a method for indicating HARQ-ACK information.

[0186] For example, by adding a separate 1-bit field to the DCI format, index 1 can indicate HARQ-ACK for a PDSCH having a high priority such as a URLLC service, and index 0 can indicate HARQ-ACK for a PDSCH having a low priority such as an eMBB service.

[0187] Alternatively, HARQ-ACK for a PDSCH for URLLC and HARQ-ACK for a PDSCH for eMBB can be distinguished by the following parameters and / or methods.

[0188] -HARQ-ACK can be distinguished by different RNTIs. That is, based on different RNTIs of a PDCCH (or DCI) for scheduling a PDSCH for URLLC and a PDCCH (or DCI) for scheduling a PDSCH for eMBB, the UE can generate a HARQ-ACK codebook by distinguishing HARQ-ACK for a PDSCH for URLLC and HARQ-ACK for a PDSCH for eMBB.

[0189] - HARQ-ACKs can be distinguished according to CORESET in which PDCCH is transmitted. That is, based on a CORESET in which a PDSCH for URLLC is transmitted and a CORESET in which a PDSCH for eMBB is transmitted, the UE can generate a HARQ-ACK codebook by distinguishing HARQ-ACKs for the PDSCH for URLLC and HARQ-ACKs for the PDSCH for eMBB.

[0190] - HARQ-ACKs can be distinguished according to DCI formats. That is, based on a DCI format for scheduling a PDSCH for URLLC and a DCI format for scheduling a PDSCH for eMBB, the UE can generate a HARQ-ACK codebook by distinguishing HARQ-ACKs for the PDSCH for URLLC and HARQ-ACKs for the PDSCH for eMBB. For example, DCI format 0_0 or DCI format 1_0 always schedules a PUSCH or a PDSCH having a low priority. In addition, DCI format 0_1 or DCI format 1_1 always schedules a PUSCH or a PDSCH having a low priority. In addition, DCI format 0_2 or DCI format 1_2 always schedules a PUSCH or a PDSCH having a high priority.

[0191] Based on the above-described method, the UE can know the priority of each PDSCH transmitted from the base station, and can generate a HARQ-ACK codebook by collecting HARQ-ACKs for PDSCHs corresponding to the same priority. Hereinafter, unless otherwise specified, the HARQ-ACK codebook described in the present disclosure refers to a HARQ-ACK codebook for PDSCHs corresponding to the same priority.

[0192] Figure 14 FIG. 13 illustrates an example of a method for transmitting HARQ-ACK based on downlink control information having different formats according to an embodiment of the present disclosure.

[0193] The DAI received from the PDCCH (or the DCI) includes a counter-DAI and a total-DAI, and each of the counter-DAI and the total-DAI can be configured with a maximum of 2 bits. However, in the DCI format 1_0, the number of bits of the counter-DAI is fixed to 2 bits, and in the DCI format 1_1, the number of bits of the counter-DAI can be set to be fixed to 2 bits, and the number of bits of the total-DAI can be set to be fixed to 2 bits.

[0194] The length of each DCI field of the DCI format 1_2 and the DCI format 0_2 for the UE can be set by the base station. For example, the base station can set the length of the DAI field for generating the HARQ-ACK codebook in the DCI format 1_2. In the DCI format 1_2, the length of the DAI field can be set to one of 0 bits, 1 bit, 2 bits, or 4 bits. If the length of the DAI field is set to 1 bit or 2 bits, the counter-DAI is 1 bit or 2 bits, and the total-DAI is 0 bits. If the length of the DAI field is set to 4 bits, the counter-DAI is 2 bits, and the total-DAI is 2 bits.

[0195] Referring to Figure 14 , the PDSCH corresponding to one HARQ-ACK codebook for one UE can be scheduled according to the DCI format 1_0, the DCI format 1_1, or the DCI format 1_2. That is, the DCI format of the PDSCH corresponding to one HARQ-ACK codebook can have a counter-DAI bit size of different lengths. Hereinafter, when the DCI format has a counter-DAI bit size of different lengths, a method for generating a HARQ-ACK codebook will be described.

[0196] Figure 15 FIG. 13 illustrates another example of a method for transmitting a HARQ-Ack based on downlink control information having different formats according to an embodiment of the disclosure.

[0197] Referring to Figure 15 , the UE can generate a HARQ-ACK codebook for the PDSCH scheduled by each PDCCH having different DCI formats, and transmit the same to the base station.

[0198] Specifically, as described above, when the DCI format changes, the number of bits of the DAI field included in each DCI can also change. In this case, the UE can generate a HARQ-ACK codebook including HARQ-ACK bits of the PDSCH scheduled by the PDCCH (or DCI) having a DAI field of a different number of bits, and transmit the same to the base station.

[0199] In this case, since the number of bits of the DAI field is different, the UE has difficulty in counting the received DAI. That is, when 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", the UE has difficulty in determining whether two received PDSCHs are consecutively transmitted.

[0200] Accordingly, when the number of bits of the counter-DAI of each received PDCCH (or DCI) is not the same, the UE can recognize the order of the received PDSCH by matching the number of bits of the counter-DAI to be the same. That is, the UE can match the number of bits by recognizing only some of the bits of the counter-DAI having a larger number of bits as valid bits, and can match the number of bits by extending and interpreting the bits of the counter-DAI having a smaller number of bits.

[0201] Proposal 1: Generate a HARQ-ACK codebook by recognizing only some bits of the counter-DAI as valid bits.

[0202] When the number of bits of the counter-DAI field of the DCI format monitored by the UE is not the same, only some bits of the counter-DAI having a larger number of bits are recognized as valid bits to generate a HARQ-ACK codebook. In this case, the number of valid bits is equal to the number of bits of the DAI field having a smaller number of bits among the DAI fields of the received PDCCH (or DCI). In addition, in the DCI format 1_0 and the DCI format 1_1, the number of bits of the counter-DAI can be fixed to 2 bits, and in the DCI format 1_2, the number of bits of the counter-DAI can be set to 0 bits, 1 bit, or 2 bits, and thus the DAI field having a smaller number of bits among the DAI fields has the same number of bits as the number of bits of the counter-DAI included in the DCI format 1_2. That is, when the UE is configured to monitor the DCI format 1_2, the UE can recognize that the number of bits of the counter-DAI of the DCI format 1_2 is the number of valid bits, and can recognize that, among the 2-bit counter-DAI of the DCI format 1_0 or the DCI format 1_1, only the number of valid bits is a valid bit of the counter-DAI.

[0203] Specifically, when the bit size of the counter-DAI of the DCI format 1_2 is set to N C-DAI bits, among the 2 bits of the counter-DAI field of the DCI format 1_0 and the DCI format 1_1, which are other formats of the DCI, only N C-DAI bits can be determined to be valid. In this case, the bits determined to be valid can be LSB N C-DAI bits or MSB N CDAI bits.

[0204] In addition, the counter-DAI value can be determined according to the value of N C-DAI bits. For example, when N C-DAIWhen the value of is "1", the number of valid bits is 1. In this case, when the binary value of the valid bit is 0, the counter-DAI value is 1, and when the binary value of the valid bit is 1, the counter-DAI value is 2.

[0205] When N C-DAI When the value of is "2", the number of valid bits is 2. In this case, when the binary value of the valid bit is 00, the counter-DAI value is 1, and when the binary value is 01, the counter-DAI value is 2. In addition, when the binary value is 10, the counter-DAI value is 3, and when the binary value is 11, the counter-DAI value is 4.

[0206] For example, Figure 15 As shown in (a), when N is the bit size of the counter-DAI of DCI format 1_2 C-DAI When configured as 1 bit, the UE can recognize that only the LSB or MSB bit of the 2 bits of the counter-DAI in DCI format 1_0 and DCI format 1_1 is the valid bit number of the counter-DAI.

[0207] That is, among the number of bits of the counter-DAI field of the received DCI, the number of bits of the counter-DAI field with the smallest number of bits is determined as the valid number of bits, and by identifying that only some bits of the LSB or MSB are valid among the bits of the counter-DAI field of the remaining DCI, the bit sizes of the counter-DAI of the received multiple DCIs can be matched identically.

[0208] The UE may use only the valid N in the Counter-DAI field of each DCI format. C-DAI bits to generate the HARQ-ACK codebook. For example, Figure 15 (a) shows that when N C-DAI The value is set to 1 bit when the counter-DAI binary value, where N C-DAI The value of is the effective bit size of Counter-DAI for DCI format 1_2.

[0209] like Figure 15 As shown in (a), the counter-DAI of DCI_format 1_1 can have binary values ​​00, 01, 10, and 11 in 2 bits, but only 1 bit (which is the LSB) can be valid. Invalid binary values ​​are marked with x. At the same monitoring opportunity, the counter-DAI value can be incremented by 1 according to the ascending order of the cell index.

[0210] Specifically, the value of the counter-DAI is a value determined according to the number of PDCCHs transmitted by the current cell up to the current monitoring occasion. If X PDCCHs (X-1 mod 2^N) have been transmitted so far, C-DAI ), the counter-DAI value is determined to be + 1. The UE can determine whether there is a PDCCH that has failed to be received by using the value of the counter-DAI.

[0211] When the format of the received DCI is DCI format 1_1 and the format of the subsequently received DCI is format 1_1, the UE may set the valid bit of the counter-DAI to 1. In this case, only the MSB or LSB of the counter-DAI field of DCI format 1_1 may be recognized as a valid bit, and the invalid bit of the counter-DAI is not used to calculate the value of the counter-DAI.

[0212] For example, Figure 15 When the DCI format 1_2 is received, the counter-DAI bit number N is shown in (a) C-DAI When the value is 1 bit, the UE can determine that the effective number of bits is 1 bit, and even if the number of bits of the counter-DAI of the DCI format 1_1 is set to 2 bits, only 1 MSB or LSB of the 2 bits can be used to determine the counter-DAI value. Figure 15 The invalid 1 bit marked with "x" in (a) is not used to determine the counter-DAI value.

[0213] If the counter-DAI bit of DCI format 1_2 is "0", the counter-DAI value may be determined to be 1. In this case, when the two bits of the counter-DAI of the next transmitted DCI format 1_1 are "11" or "01", the UE can determine the counter-DAI value by using only "1" as the value of the LSB of the valid bit. Therefore, the counter-DAI value of DCI format 1_1 can be recognized as 2.

[0214] In addition, Proposal 1 can be interpreted as follows: When the bits of the 2-bit counter-DAI of DCI format 1_0 or DCI format 1_1 are "00", the UE determines that the value of the counter-DAI is 1, and when it is "01", the value of the counter-DAI is determined to be 2, when it is "10", the value of the counter-DAI is determined to be 3, and when it is "11", the value of the counter-DAI is determined to be 4.

[0215] When the UE receives a configuration in which the number of bits of the counter-DAI of the DCI format 1_2 is 1 bit, the UE can determine the value of the counter-DAI to be 1 or 2. Here, when the value of the 2-bit counter-DAI is C2, C2 has one of 1, 2, 3, and 4. When the value of the 1-bit counter-DAI is C1, C1 has one of 1 and 2.

[0216] In this case, the value C2 of the 2-bit counter-DAI can be converted into the same bit value as the value C1 of the 1-bit counter-DAI by C1 = (C2 - 1) mod 2 + 1. This method has the same effect as determining that the 1-bit LSB is effective and interpreting 1 LSB as the 1-bit counter-DAI value in Proposal 1.

[0217] When the counter-DAI value of the previously received PDCCH (or DCI) is 1 and the counter-DAI value of the subsequently received PDCCH (or DCI) is 1, the UE can recognize that the two PDCCHs are not continuously transmitted, and at least one PDCCH has been transmitted between the two PDCCHs, but the UE has not received it.

[0218] However, when the reception of two consecutive PDCCHs fails, the UE can not be able to recognize it. That is, when N C-DAI When it is set to 1 bit, at most one PDCCH reception failure can be detected, but it is not possible to detect the reception failure of two or more consecutive PDCCHs.

[0219] As described above, in the DCI formats 1_0 and 1_1, the counter-DAI is fixed to 2 bits. Therefore, in the DCI formats 1_0 and 1_1, the counter-DAI in which the number of bits is 2 can detect the reception failure of up to three consecutive PDCCHs. However, by setting the number of effective bits to 1 bit according to the number of bits of the counter-DAI of the DCI format 1_2 of Proposal 1, the PDCCH reception failure detection performance can be degraded.

[0220] Proposal 2: Generate a HARQ-ACK codebook based on the maximum number of bits among the bits of the counter-DAI.

[0221] In the case of Proposal 1, as described above, since the number of effective bits of the counter-DAI is only 1 bit, it is not possible to recognize that two or more consecutive PDCCHs are not detected. Therefore, it can not be easy to detect the reception failure of the PDCCH.

[0222] To solve this problem, when the number of bits of the counter-DAI varies depending on the format of the DCI, the value of the counter-DAI can be determined by expanding and interpreting the number of bits of the counter-DAI based on more bits.

[0223] Specifically, when the bit size of the counter-DAI of DCI format 1_2 is configured with N C-DAI bits, N C-DAI The 2-bit counter-DAI is expanded and interpreted as a 2-bit counter-DAI value. In addition, it can be determined that the 2-bit counter DAI for DCI format 1_0 and DCI format 1_1 is valid.

[0224] For example, Figure 15 As shown in (b), DCI format 1_0 and DCI format 1_1 include a two-bit counter-DAI, and therefore, when the bit of the counter-DAI is "00" of the binary number, the counter-DAI value may be 1, and when the bit is "01" of the binary number, the counter-DAI value may be 2. In addition, when the bit of the counter-DAI is 10 of the binary number, the counter-DAI value may be 3, and when the bit of the counter-DAI is 11 of the binary number, the counter-DAI value may be 4.

[0225] In this case, when the bit size N of the counter-DAI of DCI format 1_2 is C-DAI When the value of is 1 bit, the UE may extend the number of bits of the Counter-DAI of DCI format 1_2 and interpret it as 2 bits. For example, when 1 bit (which is "0") of the Counter-DAI of DCI format 1_2 is extended and interpreted as 2 bits, the Counter-DAI may have a bit value of "00" or "10". Therefore, the Counter-DAI value may be extended and interpreted as 1 or 3.

[0226] Alternatively, when 1 bit (which is '1') of the counter-DAI of DCI format 1_2 is expanded and interpreted as 2 bits, the counter-DAI may have a bit value of '01' or '11'. Therefore, the counter-DAI value may be expanded and interpreted as 2 or 4.

[0227] When the Counter-DAI of DCI format 1_2 with a size of 1 bit is extended and interpreted as 2 bits according to Proposal 2, the value of the Counter-DAI can have two or more candidate values ​​according to the extended interpretation. In this case, the UE can recognize that the value with the smallest number of non-contiguous PDCCHs is the value of the Counter-DAI. That is, when the interpretation is performed by extending the number of bits of the Counter-DAI, the UE can determine the value corresponding to the value with the smallest number of undetected PDCCHs as the value of the Counter-DAI.

[0228] For example, when the value of the 2-bit counter-DAI of the previously received DCI is 3 and the bit of the 1-bit counter-DAI of the subsequently received PDCCH (or DCI) is “1”, the UE can determine the value 4 as the counter-DAI by extending and interpreting the 1-bit counter-DAI as 2 bits, which is the value 4 among the candidate values 2 or 4 of the value of the counter-DAI having the smallest number of undetected PDCCHs. In other words, when the counter-DAI of the subsequently received PDCCH (or DCI) is determined to be 2, it is determined that the reception of two PDCCHs (or DCIs) having the counter-DAI values 4 and 1 has failed. However, when the counter-DAI of the received PDCCH (or DCI) is determined to be 4, the UE determines that there is no failed reception of the PDCCH (or DCI). When the probability that the UE fails to receive the PDCCH is p, the probability that the counter-DAI is determined to be 2 and the reception of two consecutive PDCCHs (or DCIs) fails is p 2 , and the probability that the counter-DAI is determined to be 4 and no PDCCH (or DCI) reception fails is 1-p. Generally, p is a very small value for the base station to allow the UE to successfully receive the PDCCH (or DCI). Therefore, the counter-DAI 4 having the probability 1-p occurs more frequently than the counter-DAI 2 having the probability p 2 . Thus, in the above case, the value of the counter-DAI is more likely to be 4 than 2, and thus it is desirable to determine the counter-DAI as 4.

[0229] Table 7 below shows an example of the value of the counter-DAI for which the counter-DAI of the previously received DCI is extended and interpreted when the bits of the counter-DAI are extended and interpreted. Here, the counter-DAI is 1 bit, and the value of the counter-DAI of the previously received DCI is 2 bits.

[0230] [Table 7]

[0231]

[0232] In Table 7, the numbers in parentheses indicate each bit value.

[0233] For another example of Proposal 2, the DCI format 1_0 and the DCI format 1_1 include a two-bit counter-DAI, and thus, when the bits of the counter-DAI are “00” of a binary number, the counter-DAI value can be 1, and when the bits are “01” of a binary number, the counter-DAI value can be 2. In addition, when the bits of the counter-DAI are “10” of a binary number, the counter-DAI value can be 3, and when the bits of the counter-DAI are “11” of a binary number, the counter-DAI value can be 4.

[0234] In this case, when the value of the counter-DAI of the DCI format 1_2 is 0 bits C-DAI , the UE can extend the number of bits of the counter-DAI of the DCI format 1_2 and interpret it as 2 bits. In this case, since the size of the counter-DAI is 0 bits, when it is extended and interpreted as 2 bits, the counter-DAI of 0 bits can have four candidate values.

[0235] When the counter-DAI value is extended and interpreted as a value having the smallest number of undetected PDCCHs among the four candidate values, the UE can determine the counter-DAI value as a value consecutive to the counter-DAI value of the previously received DCI.

[0236] Table 8 below shows an example of the counter-DAI value of the counter-DAI extended and interpreted for the previously received DCI when the bits of the counter-DAI are extended and interpreted. Here, the counter-DAI is 0 bits, and the value of the counter-DAI of the previously received DCI is 2 bits.

[0237] [Table 8]

[0238]

[0239] That is, when the bit size of the counter-DAI of the DCI format 1_2 is less than 2 bits, there can be multiple possible 2-bit counter-DAI values. The UE can select one value from among the multiple possible 2-bit counter-DAI values.

[0240] To select one of the multiple candidate values, the following specific method can be used.

[0241] When the counter-DAI value of the PDCCH received immediately before is C and the currently received counter-DAI of the DCI format 1_2 is interpreted as 2 bits, assume that the possible 2-bit counter-DAI values are i1, i2,.... The UE needs to determine one value among i1, i2,... as the 2-bit counter-DAI value by using V temp or the C value.

[0242] The UE can calculate the value of Y in the order of x = 1, 2, 3,... based on Equation 2 below.

[0243] [Equation 2]

[0244] Y = ((V temp or C) + x - 1 mod 4) + 1

[0245] If Y is one of i1, i2,..., the UE determines the value of the 2-bit counter-DAI to be Y. This is a method for setting the 2-bit counter-DAI value to minimize the number of failed PDCCH receptions since the most recently received PDCCH until the currently received DCI format 1_2.

[0246] In Tables 4 and 5, V temp is the value of the immediately preceding counter-DAI with a 2-bit size (i.e., the cell with a low cell index in the current monitoring occasion or the last received PDCCH in the previous monitoring occasion) (interpreted as the value of the 2-bit counter-DAI value when the last received DCI format is DCI format 1_2).

[0247] For example, when V temp is 1 and the currently received counter-DAI of DCI format 1_2 is 0 in binary, the counter-DAI can have a value of 1 or 3. When the counter-DAI value is determined to be 3, it indicates a case where one PDCCH (counter-DAI value is 2) has been transmitted but failed to be received between the previously received PDCCH (counter-DAI value is 1) and the currently received PDCCH (counter-DAI value is 3). When the counter-DAI value is determined to be 1, it indicates a case where three PDCCHs (counter-DAI values are 2, 3, and 4) have been transmitted but failed to be received between the previously received PDCCH (counter-DAI value is 1) and the currently received PDCCH (counter-DAI value is 1). According to the previous embodiment, it is assumed that the minimum number of PDCCHs have been transmitted but failed to be received, and it can be determined that the value of the counter-DAI of the currently received PDCCH is 3.

[0248] In proposals 1 and 2, only the counter-DAI is used when generating the HARQ-ACK codebook, but the HARQ-ACK codebook can be generated by additionally using the total-DAI value. For example, in DCI format 1_2, the total-DAI can be configured with N T-DAI bits. In this case, similar to the method of proposal 1, only the LSB (or MSB) N T-DAI bits in the two-bit total-DAI field of DCI format 1_1 including the 2-bit total-DAI field are determined as valid bits, and the total-DAI value can be determined based on the valid N T-DAI bits.

[0249] In another embodiment of the disclosure, a HARQ-ACK codebook can be generated by using a total DAI value of 2 bits. The total-DAI value is determined according to the number of PDCCHs received until the current monitoring occasion. If the number of PDCCHs received until the current monitoring occasion is T, N T-DAI bits of total-DAI can be determined as ((T-1) mod 2^N T-DAI )+1. The PDCCHs received in one monitoring occasion have the same total-DAI value of 2 bits.

[0250] In another embodiment of the disclosure, when at least one DCI format 1_1 is received in one monitoring occasion, a total-DAI value of 2 bits included in the DCI format 1_1 can be used. That is, when a DCI format including a total-DAI of 2 bits and a DCI format including a total-DAI of 1 bit or a total-DAI of 0 bits are received in the same monitoring occasion, the total-DAI of 2 bits contains the most information, and thus the total-DAI value of 2 bits can be assumed.

[0251] In another embodiment of the disclosure, when no DCI format 1_1 is received in one monitoring occasion and a DCI format 1_2 is received, the value of the total-DAI of 2 bits can be determined as follows.

[0252] When the value of N T-DAI , which is the bit size of the total-DAI in the DCI format 1_2, is 1 bit, it can be extended and interpreted as a total-DAI value of 2 bits. For example, when the bit of the total-DAI of 1 bit is '0', the total-DAI value can be 1 or 3, and when the bit is '1', the total-DAI value can be 2 or 4.

[0253] When the value of N T-DAI , which is the bit size of the total-DAI in the DCI format 1_2, is 0 bits (i.e., when the total-DAI is not included in the DCI format), the total-DAI of 0 bits can be interpreted as a total-DAI value of 2 bits.

[0254] For example, the value of the total-DAI of 0 bits can be 1, 2, 3, or 4. That is, when the bit size of the total-DAI of the DCI format 1_2 is less than 2 bits, the total-DAI of 2 bits can have multiple candidate values. In this case, one value can be selected from among the multiple candidate values by the following method.

[0255] The value of the 2-bit counter-DAI of the last received PDCCH (i.e., received from the cell with the highest cell index) among the PDCCHs received in the current monitoring occasion can be C, and the total-DAI including in the DCI on the PDCCH received in the corresponding monitoring occasion can have a value of the 2-bit total-DAI of j1, j2,....

[0256] In this case, the UE needs to determine one value among j1, j2,... as the value of the 2-bit total-DAI using the C value. The UE can calculate the value of Z based on the following Equation 3 in order according to the value of x (x = 0, 1, 2, 3,...).

[0257] [Equation 3]

[0258] Z = ((V temp or C) + x - 1 mod 4) + 1

[0259] If Z is one value among j1, j2,..., the UE determines that the value of the 2-bit total-DAI is Z. This is a method for setting the value of the 2-bit total-DAI to minimize the number of PDCCHs that have failed to be received since the last PDCCH of the current monitoring occasion among the PDCCHs that have been transmitted.

[0260] Table 9 below is a table showing an example of the total-DAI value selected from among a plurality of candidate values.

[0261] [Table 9]

[0262]

[0263] In Table 9, V temp2 is the value of the 2-bit counter-DAI of the last PDCCH among the PDCCHs received in the monitoring occasion. For example, when the previous V temp2 has a value of 2 and the currently received counter-DAI of the DCI format 1_2 is a binary number 0, the total-DAI can have 1 or 3.

[0264] When the total-DAI value is determined to be 3, it indicates a case where one PDCCH (counter-DAI value of 3) has been transmitted since the last received PDCCH (counter-DAI value of 2) but the UE has not detected it. When the total-DAI value is determined to be 1, it indicates a case where three PDCCHs (counter-DAI values of 3, 4, and 1) have been transmitted since the last received PDCCH (counter-DAI value of 2) but the UE has not detected them. According to the previous embodiment, it is assumed that the minimum number of PDCCHs has been transmitted but their reception has failed, and it can be determined that the value of the total-DAI of the received PDCCH is 3.

[0265] Through the above-described method, even when the number of bits of the counter-DAI or the total-DAI of the DCI having different formats is different, the UE can determine the number of valid bits or extend and interpret the number of bits, and multiplex the HARQ-ACK codebook of the PDSCH scheduled by the plurality of DCIs and transmit it to the base station.

[0266] Figure 16 FIG. 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 disclosure.

[0267] Referring to Figure 16 , the UE multiplexes the PUSCH scheduled by the DCI and the HARQ-ACK codebook including the HARQ-ACK bits of the PDSCH scheduled by the DCI on the PDCCH, and transmits them to the base station.

[0268] Specifically, as Figure 16 indicated, the UE can multiplex (or piggyback) the HARQ-ACK bits of the received PDSCH with the PUSCH and transmit them 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 multiplexed (or piggybacked) with the HARQ-ACK bits includes DCI format 0_0, DCI format 0_1, DCI format 0_2, etc.

[0269] The length of the UL DAI field included in the DCI format 0_2 can be set to 0, 1, or 2 bits. In addition, the length of the counter-DAI field included in the DCI format 1_2 can be set to 0, 1, or 2 bits.

[0270] In addition, the DCI format 0_0 and the DCI format 0_1 can include a 2-bit UL DAI field, and the DCI format 1_0 and the DCI format 1_1 can include a 2-bit counter-DAI field.

[0271] In this case, when the length of the UL DAI field is different from the length of the counter-DAI field of the DCI format 1_2, it is necessary to determine the value of the UL DAI field based on the counter-DAI field. Hereinafter, in this embodiment, it is assumed that the length of the DAI field is at least not 0, i.e., the DCI format can include a DAI field having a length of at least 1 bit.

[0272] In the first embodiment, when the length of the UL DAI field is greater than the length of the counter-DAI field of DCI format 1_2 (e.g., when the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the UE can determine only some bits of the UL DAI field as valid bits of the UL DAI field. Here, the number of some bits is the same as the number of bits of the counter-DAI field, and can be the bits closest to the MSB or LSB of the UL DAI field.

[0273] The UE can calculate the UL DAI value by using the bits of the UL DAI field that are determined as valid bits among the bits of the UL DAI field. If the UL DAI field has one valid bit, the UL DAI value is 1 when the bit is "0" and 2 when it is 1.

[0274] If the UL DAI field has two valid bits, the UL DAI value is 1 when the bits are "00", 2 when they are 01, further, 3 when the 2 bits are 10, and 4 when the 2 bits are 11.

[0275] The UE can determine the number of HARQ-ACK bits for PDSCHs that are not received using the UL DAI value obtained by using the bits of the UL DAI field that are determined as valid and the counter-DAI value obtained from the counter-DAI field.

[0276] For example, let the UL DAI value be X and the counter-DAI value be Y. If X = Y, it can be determined that there is no PDSCH that is not received. However, when Y < X, it can be determined that X-Y PDSCHs are not received, and when X < Y, it can be determined that T-(Y-X) PDSCHs are not received. Here, T = 2 N , and N is the number of bits of the counter-DAI field.

[0277] In the second embodiment, when the length of the UL DAI field is greater than the length of the counter-DAI field of DCI format 1_2 (e.g., the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the UE can first determine the UL DAI value according to the length of the UL DAI field, and then modify the determined UL DAI value according to the counter-DAI field, thereby determining the final UL DAI value.

[0278] The procedure for determining the value of UL DAI according to the length of UL DAI field is as follows. If the UL DAI field has a field length of 1 bit, the UL DAI value is 1 when the bit value is "0", and the UL DAI value is 2 when the bit value is "1".

[0279] If the UL DAI field has a field length of 2 bits, the UL DAI value is 1 when the bit value is "00", and the UL DAI value is 2 when the bit value is "01". In addition, when the bit value is "10", the UL DAI value is 3, and when the bit value is "11", the UL DAI value is 4.

[0280] When the UL DAI value is determined according to the UL DAI field, the UE can modify the determined UL DAI value to match the counter-DAI field as follows to determine the final UL DAI value.

[0281] When T = 2 N , where N is the number of bits of the counter-DAI field and the determined UL DAI value is Z, the final UL DAI value (X) can be calculated using Equation 4 below.

[0282] [Equation 4]

[0283] Final UL DAI value (X) = ((Z-1) mod T) + 1

[0284] The UE can determine the number of HARQ-ACK bits for PDSCHs not received using the final UL DAI value X and the counter-DAI value obtained from the counter-DAI field. For example, when the counter-DAI value is Y, it can be determined that there is no PDSCH not received when X = Y. However, when Y < X, it can be determined that X-Y PDSCHs are not received, and when X < Y, it can be determined that T-(Y-X) PDSCHs are not received. Here, T = 2 N , and N is the number of bits of the counter-DAI field.

[0285] In a third embodiment, when the length of the UL DAI field is greater than the length of the counter-DAI field of DCI format 1_2 (for example, the length of the UL DAI field is 2 bits, and the length of the counter-DAI field is 1 bit), the UE can assume (or recognize) that the range of the UL DAI value is the same as the range of values that the counter-DAI can indicate. For example, when the counter-DAI can indicate values of 1, 2, 3, or 4, the value of the UL DAI can be recognized as one of 1, 2, 3, and 4.

[0286] Specifically, the UE can determine the value of the UL DAI according to the length of the UL DAI field. If the UL DAI field has a field length of 1 bit, the UL DAI value is 1 when the bit value is "0" and the UL DAI value is 2 when the bit value is "1". If the UL DAI field has a field length of 2 bits, the UL DAI value is 1 when the bit value is "00" and the UL DAI value is 2 when the bit value is "01". Also, when the 2-bit bit value is "10", the UL DAI value is 3, and when the bit value is "11", the UL DAI value is 4.

[0287] The UL DAI value always needs to be within the range of values that the counter-DAI can indicate. For example, when the UL DAI field has a length of 2 bits, the range of the UL DAI value is 1, 2, 3, and 4. If the counter-DAI value can have a range of 1 and 2, the length of the UL DAI field is 2 bits, but the value that the UL DAI can have is 1 and 2.

[0288] That is, the UE does not expect to be indicated with the UL DAI value indicating a value outside the range of values that the counter-DAI can have. 10 or 11 indicating a value in which the UL DAI is 3 or 4 is not expected. That is, when this value is indicated, the UE can determine an error situation.

[0289] As described above, in the DCI format 0_2, the length of the UL DAI field can be set to 0, 1, or 2 bits. When the length of the UL DAI field is less than 2 bits, for the UL DAI, the 2-bit UL DAI value can be determined in the same manner as the method for determining the 2-bit total-DAI value.

[0290] That is, the value of the UL DAI can be determined by using the last received 2-bit counter-DAI value. Table 10 below is a table showing an example of the 2-bit UL-DAI value.

[0291] [Table 10]

[0292]

[0293] In Table 10, V temp3 is the 2-bit counter-DAI value of the last PDCCH among the received PDCCHs. For example, when the previous V temp3 The value of the UL-DAI can have 1 or 3 when the value of V

[0294] When the UL-DAI value is determined as 3, it indicates a case where one PDCCH (counter-DAI value of 3) has been transmitted since the last received PDCCH (counter-DAI value of 2) but its reception has failed, and when the UL-DAI value is determined as 1, it indicates a case where three PDCCHs (counter-DAI values of 3, 4, and 1) have been transmitted since the last received PDCCH (counter-DAI value of 2) but their reception has failed. As described above, when it is assumed that the minimum number of PDCCHs have been transmitted but their reception has failed, the 2-bit UL-DAI value can be determined as 3.

[0295] Figure 17 FIG. illustrates an example of a downlink assignment indicator of each downlink control information detected in a monitoring occasion according to an embodiment of the disclosure.

[0296] In another embodiment of the disclosure, when the UE has a bit size of the UL DAI field of DCI format 0_0, 0_1, or 0_2 that is different from that of the counter-DAI field of DCI format 1_0, 1_1, or DCI format 1_2, the UE can perform the following operations.

[0297] When the bit size of the counter-DAI field of DCI format 1_0, 1_1, or 1_2 is N C-DAI bits, the counter-DAI value can indicate 1, 2,..., 2^N C-DAI . Here, when the maximum value C D is 2^N C-DAI , that is, when the bit size N C-DAI of the counter-DAI field is 2 bits, when the bit value of the counter-DAI field is "00", the counter-DAI value can be 1, when "01" is 2, when "10" is 3, and when "11" is 4. In this case, the value of C D may be 4.

[0298] Alternatively, when N C-DAI is 1 bit, the counter-DAI value can be 1 when the value of the counter-DAI field is 0, and 2 when 1, where the value of C D is 2.

[0299] If the UE receives a DCI format for scheduling a PDSCH in a serving cell c of a monitoring occasion m and the counter-DAI value of the received DCI format is V C-DAI,c,m , the UE can determine that, until the current serving cell c of the current monitoring occasion m of the DCI format has been received, C D *j+V C-DAI,c,mDCI formats. Here, j is a non-negative integer.

[0300] In other words, when the number of DCI formats for scheduling PDSCH that have been received up to the current monitoring occasion m of the current serving cell c is X, the counter-DAI value of the DCI format is V C-DAI,c,m = (X - 1 mod C D ) + 1.

[0301] When the bit size of the UL DAI field of the DCI format 0_0, 0_1, or 0_2 is N UL-DAI bits, the UL DAI value can be expressed as 1, 2,..., 2^N UL-DAI . Here, when the maximum value U D is 2^N UL-DAI , i.e., when the bit size N UL-DAI of the UL DAI field is 2 bits, when the bit value of the UL DAI field is "00", the UL DAI value is 1, when "01", 2, when "10", 3, and when "11", 4. In addition, the value of U D is 4.

[0302] If the UE receives a DCI format for scheduling PUSCH in the monitoring occasion m and the UL-DAI value of the received DCI format is V UL-DAI,m , the UE can determine that U D *i+V UL-DAI,m DCI formats for scheduling PDSCH have been received up to the current monitoring occasion m of the received DCI format. Here, i is a non-negative integer.

[0303] In other words, when the number of DCI formats for scheduling PDSCH that have been received up to the current monitoring occasion m is X, the UL-DAI value of the DCI format is V UL-DAI,m = (X - 1 mod U D ) + 1.

[0304] For example, when the value of U D is 4 and the value of C D is 2, the counter-DAI value can be 1 or 2, and the UL-DAI value can be 1, 2, 3, or 4. Figure 17 FIG. (a) illustrates an example of the counter-DAI value of the DCI format received in monitoring occasions (MOs) #0 to #6.

[0305] According to the definition of the counter-DAI value, the counter-DAI value of the DCI format received on MO#0 is 1, the counter-DAI value of the DCI format received on MO#1 is 2, the counter-DAI value of the DCI format received on MO#2 is 1, the counter-DAI value of the DCI format received on MO#3 is 2, the counter-DAI value of the DCI format received on MO#4 is 1, the counter-DAI value of the DCI format received on MO#5 is 2, and the counter-DAI value of the DCI format received on MO#6 is 1. Also, the UE 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 PDSCH have been received previously.

[0306] In the disclosure, when the bit size of the counter-DAI and the bit size of the UL DAI are different from each other, a method for generating a HARQ-ACK codebook by a UE is proposed. It is assumed that the UE does not receive the DCI formats of MO#4 and MO#5 in (b) of Figure 17 Since the UE has received the DCI format in which the counter-DAI value is 2 on MO#3 and the DCI format in which the counter-DAI value is 1 on MO#6, the UE can not know that the reception of the DCI formats on MO#4 and MO#5 has failed. Therefore, the UE generates only the HARQ-ACK bits for the DCI formats received on MO#0, MO#1, MO#2, MO#3, and MO#6, and includes them in the HARQ-ACK codebook.

[0307] If the UE receives 3 as the UL-DAI value in the DCI format for scheduling a PUSCH, the UE can recognize that there are two DCI formats in addition to the five DCI formats that have been successfully received. Therefore, the UE can generate the HARQ-ACK bits of a total of seven DCI formats, and include them in the HARQ-ACK codebook.

[0308] Figure 19 An example of a method of transmitting HARQ-ACK based on downlink control information having different formats based on a pseudo code according to an embodiment of the disclosure is illustrated.

[0309] Referring to Figure 19 The HARQ-ACK codebook can be generated using the UL-DAI value and the counter-DAI value using a pseudo code, and transmitted to the base station. Figure 19 An example of multiplexing a 2-bit UL-DAI and a 1-bit counter-DAI is illustrated.

[0310] Specifically, in the embodiments of the present disclosure, the UL-DAI value and the counter-DAI value may be used as follows. First, as Figure 19 As shown in (a), let the counter-DAI value received by the UE at the last MO be V temp As mentioned before, the counter-DAI value can have 1, 2, ..., C D Let the UL DAI value received by the UE in the DCI format used to schedule PUSCH be V temp2 The UE generates the HARQ-ACK codebook through the following process.

[0311] First, UE can use V temp Determine the number of DCI formats W used to schedule PDSCH temp .W temp It can be determined by the following equation 5.

[0312] [Equation 5]

[0313] W temp =C D *j+V temp

[0314] In Equation 5, the initial value of j is set to 0, and when the counter-DAI value of the DCI format for scheduling PDSCH on the current MO is less than the counter-DAI value of the DCI format for scheduling PDSCH on the previous MO, it can be incremented by one. That is, with counter-DAI values ​​1, 2, ... C D The DCI formats of are grouped into one group, and j indicates how many groups have been received. Figure 17 In (b), j=2.

[0315] Then, the UE uses the number W of DCI formats used to schedule PDSCH temp Convert to V' temp , the V' temp Yes and N UL-DAI The corresponding counter-DAI value, the N UL-DAI is the bit size of the UL DAI field, such as Figure 19 As shown in (b).

[0316] [Equation 6]

[0317] V' temp =((W temp -1)mod U D )+1

[0318] In Equation 6, V' temp With 1, 2, ..., U Done of V temp and V temp2 , similar to UL DAI. The UE can determine the value of j by comparing V temp2 < V' temp . The value of j can be determined by Equation 7 below if V

[0319] [Equation 7]

[0320]

[0321] Otherwise, j can remain the same. Using the value of j, the UE can determine the size O ACK of the HARQ-ACK codebook. If the UE is configured to receive only 1 TB per PDSCH, O ACK may be calculated by Equation 8 below.

[0322] [Equation 8]

[0323]

[0324] If the UE is configured to receive 2 TB per PDSCH, O ACK may be calculated by Equation 9 below.

[0325] [Equation 9]

[0326]

[0327] When this is expressed in pseudo code, it is shown in Table 11 below.

[0328] [Table 11]

[0329]

[0330]

[0331]

[0332] Figure 18 Another example of a downlink assignment indicator for each piece of downlink control information detected in a monitoring occasion according to an embodiment of the disclosure is illustrated.

[0333] In another embodiment of the disclosure, when the UE has a bit size of the total DAI field of DCI format 1_0, 1_1, or 1_2 that is different from that of the counter-DAI field of DCI format 1_0, 1_1, or 1_2, the UE can generate a HARQ-ACK codebook by the following operations.

[0334] When the bit size of the counter-DAI field of DCI format 1_0, 1_1, or 1_2 is NC-DAI The counter-DAI value can indicate 1, 2,..., 2^N C-DAI bits. Here, when the maximum value C D is 2^N C-DAI , that is, when the bit size N C-DAI of the counter-DAI field is 2 bits, the counter-DAI value can be 1 when the bit value of the counter-DAI field is "00", 2 when "01", 3 when "10", and 4 when "11". In this case, the value of C D may be 4.

[0335] Alternatively, when N C-DAI is 1 bit, the counter-DAI value can be 1 when the value of the counter-DAI field is 0, and 2 when 1, where the value of C D is 2.

[0336] If the UE receives a DCI format for scheduling a PDSCH in a serving cell c for monitoring occasion m and the counter-DAI value of the received DCI format is V C-DAI,c,m , the UE can determine that C D *j+V C-DAI,c,m DCI formats for scheduling a PDSCH have been received until the current serving cell c for the current monitoring occasion m in which the DCI format has been received. Here, j is a non-negative integer.

[0337] In other words, when the number of DCI formats for scheduling a PDSCH until the current monitoring occasion m in which the DCI format has been received for the current serving cell c is X, the counter-DAI value of the DCI format is V C-DAI,c,m =(X-1 mod C D )+1.

[0338] When the bit size of the total-DAI field of the DCI format 1_0, 1_1, or 1_2 is N T-DAI bits, the total-DAI value can indicate 1, 2,..., 2^N T-DAI . Here, when the maximum value T D is 2^N T-DAI , that is, when the bit size N T-DAI of the total-DAI field is 2 bits, the total-DAI value is 1 when the bit value of the total-DAI field is "00", 2 when "01", 3 when "10", and 4 when "11". In addition, the value of T D is 4.

[0339] If the UE receives a DCI format for scheduling a PDSCH in a serving cell c for monitoring occasion m and the total-DAI value of the DCI format is VT-DAI,m , the UE can determine that T D + i T-DAI,m DCI formats have been received until the current monitoring occasion m of the DCI format is received. Here, i is a non-negative integer.

[0340] In other words, when the number of DCI formats for scheduling PDSCH until the current monitoring occasion m of the DCI format has been received is X, the total-DAI value V T-DAI,c,m of the DCI format is (X - 1 mod T D ) + 1.

[0341] As an example, a case where the value of T D is 4 and the value of C D is 2 is observed. The values 1 or 2 can be set as the counter-DAI value of the UE, and the total-DAI can have the values 1, 2, 3, or 4.

[0342] Figure 18 (a) of FIG. illustrates the (counter-DAI, total-DAI) values of the DCI formats received on MO#0 to #6. According to the definitions of the counter-DAI value and the total-DAI value, the (counter-DAI, total-DAI) of the DCI format received on MO#0 is (1, 1), the (counter-DAI, total-DAI) of the DCI format received on MO#1 is (2, 2), the (counter-DAI, total-DAI) of the DCI format received on MO#2 is (1, 3), the (counter-DAI, total-DAI) of the DCI format received on MO#3 is (2, 4), the (counter-DAI, total-DAI) of the DCI format received on MO#4 is (1, 1), the (counter-DAI, total-DAI) of the DCI format received on MO#5 is (2, 2), and the (counter-DAI, total-DAI) of the DCI format received on MO#6 is (1, 3).

[0343] As another example of the disclosure, when the bit size of the counter-DAI and the bit size of the total-DAI are different from each other, a method for generating a HARQ-ACK codebook by a UE is proposed. As shown in (b) of FIG. Figure 18 The UE can not receive the DCI formats of MO#4 and MO#5. In this case, the UE has received the DCI format with the counter DAI value of 2 on MO#3 and the DCI format with the counter DAI value of 1 on MO#6, so the UE can not recognize the reception failure of the DCI formats on MO#4 and MO#5.

[0344] Therefore, the UE generates HARQ-ACK bits only for DCI formats received on MO#0, MO#1, MO#2, MO#3 and MO#6, and includes them in the HARQ-ACK codebook.

[0345] If the UE receives 3 as the total-DAI value in the DCI format for scheduling the PDSCH, the UE can determine that there are two more DCI formats in addition to the five DCI formats that have been successfully received. Therefore, the UE can generate HARQ-ACK bits for a total of seven DCI formats and include them in the HARQ-ACK codebook.

[0346] Specifically, in an embodiment of the present disclosure, the total-DAI value and the counter-DAI value may be used as follows. First, the value of the counter-DAI received by the UE on the last MO may be V temp As mentioned above, the counter-DAI value can have 1, 2, ..., C D When the total DAI value received by the UE in the DCI format used to schedule PDSCH is V temp2 When , the UE can generate the HARQ-ACK codebook through the following process.

[0347] First, the UE can use V temp To determine W temp , W temp is the number of DCI formats used to schedule PDSCH.

[0348] [Equation 10]

[0349] W temp =C D *j+V temp

[0350] In Equation 10, the initial value of j may be set to 0, and may be incremented by one when the counter-DAI value of the DCI format for scheduling PDSCH on the current MO is less than the counter-DAI value of the DCI format for scheduling PDSCH on the previous MO.

[0351] That is, with counter-DAI values ​​1, 2, ... C D The DCI formats are grouped into one group, and j indicates how many packets of the group have been received. Figure 18 In (a), j=2.

[0352] Next, the UE will use the number of DCI formats W for scheduling PDSCH temp Convert to V' temp , the V' temp Yes and NT-DAI the corresponding counter-DAI value, the N T-DAI is the bit size of the total-DAI field. This can be performed by Equation 11 below.

[0353] [Equation 11]

[0354] V' temp = ((W temp - 1) mod T D ) + 1

[0355] In Equation 11, V' temp has one of 1, 2,..., T D , similar to the total-DAI. The UE can determine the value of j by comparing V' temp and V temp2 . If V temp2 < V' temp , the value of j can be calculated by Equation 12 below.

[0356] [Equation 12]

[0357]

[0358] Otherwise, j can remain the same. Using the value of j, the UE can determine the size O ACK of the HARQ-ACK codebook. If the UE is configured to receive only 1 TB per PDSCH, O ACK can be calculated by Equation 13 below.

[0359] [Equation 13]

[0360]

[0361] If the UE is configured to receive 2 TB per PDSCH, O ACK can be calculated by Equation 14 below.

[0362] [Equation 14]

[0363]

[0364] In another embodiment of the disclosure, when the bit sizes of the counter-DAI fields of DCI formats 1_0, 1_1, or 1_2 are different from each other, the UE can perform the following operations.

[0365] The bit size of the counter-DAI field of DCI formats 1_0, 1_1, or 1_2 received in the serving cell c at the monitoring occasion m can be N C-DAI,c,m bits. In this case, the counter-DAI value can be represented as 1, 2,..., 2^NC-DAI,c,m Here, the maximum value C D,c,m may be 2^N C-DAI,c,m . That is, when the bit size N C-DAI,c,m of the counter-DAI field is 2 bits, when the bit value of the counter-DAI field is "00", the counter-DAI value is 1, when "01", 2, when "10", 3, and when "11", 4. Also, the value of C D is 4, when N C-DAI,c,m is 1 bit, the counter-DAI value is 1 when the bit value of the counter-DAI field is 0, and 2 when 1, and also, the value of C D,c,m is 2.

[0366] If the UE receives a DCI format for scheduling a PDSCH in a serving cell c at a monitoring occasion m and the counter-DAI value of the received DCI format is V C-DAI,c,m , the UE can determine that C D,c,m *j+V C-DAI,c,m DCI formats for scheduling a PDSCH have been received until the current serving cell c at the current monitoring occasion m where the DCI format has been received. Here, j is a non-negative integer.

[0367] In other words, when the number of DCI formats for scheduling a PDSCH until the current monitoring occasion m where the DCI format has been received in the current serving cell c is X, the counter-DAI value V C-DAI,c,m of the DCI format is (X-1 mod C D,c,m )+1.

[0368] In the disclosure, when the bit sizes of the counter-DAI are not the same as each other, a method for generating a HARQ-ACK codebook by the UE is proposed. In an embodiment of the disclosure, the counter-DAI value is used as follows.

[0369] N C-DAI,min is assumed to be the minimum bit size among the bit sizes of the counter-DAI fields of the DCI formats, and the value of C D,min may be 2^(N C-DAI,min ). For example, when the bit size of the counter-DAI field of one DCI format is 2 bits and the bit size of the counter-DAI field of another DCI format is 1 bit, the value of N C-DAI,min is 1, and the value of C D,min is 2.

[0370] When the value of the counter-DAI received in the serving cell c at the monitoring occasion m is V C-DAI,c,m , the value of the counter-DAI can have 1, 2,..., CD,c,m One of the following equations 15 can be used by the UE to determine the number S C-DAI,c,m of DCI formats for scheduling PDSCH based on the following equation 15 c,m .

[0371] [Equation 15]

[0372]

[0373] In Equation 15, the part of floor(j*C D,min / C D,c,m )*C D,c,m is the part for making the number S c,m of DCI formats for scheduling PDSCH satisfy (S c,m -1 mod C D,c,m )+1=V C-DAI,c,m .

[0374] That is, the value of j can be adjusted by scaling and / or down-integer to make the value of S c,m -V C-DAI,c,m be a multiple of C D,c,m in Equation 15.

[0375] The UE will compare the number S c,m of DCI formats obtained based on the counter DAI value received in the serving cell c at the current monitoring occasion m with the number W temp of DCI formats obtained just before. If S c,m ≤W temp , the value of j can be incremented until S c,m >W temp . In this case, the value of j can be incremented by one. If S c,m >W temp , j can remain the same.

[0376] j is a parameter indicating how many C D,min DCI formats have been received.

[0377] When this is expressed in pseudo code, it is shown in Table 12 below.

[0378] [Table 12]

[0379]

[0380]

[0381]

[0382] In Table 12, when the HARQ-ACK codebook is multiplexed with the PUSCH, T D = U D , V temp2 may be set to the value of the UL DAI.

[0383] The DCI format 1_2 can not include the counter-DAI (this includes being configured with 0 bits). In this case, the UE can have ambiguity about the method for determining the dynamic HARQ-ACK codebook. That is, in designing the dynamic HARQ-ACK codebook (type 2 HARQ-ACK codebook), the base station can be configured to omit some of the DCI fields in order to increase the PDCCH reception success probability of the UE. That is, the base station can omit some of the DCI fields or set the field size to 0 bits.

[0384] For example, the base station can omit the counter-DAI field from among the DCI fields to be transmitted to the UE, or set the size of the field to 0 bits.

[0385] As described above, in the dynamic HARQ-ACK codebook, the counter-DAI field can not only be used to determine the position of the HARQ-ACK bit in the HARQ-ACK codebook, but also to determine the size of the HARQ-ACK codebook.

[0386] In order for the UE to transmit the HARQ-ACK bit for notifying the base station of ACK / NACK (or DTX) for a plurality of PDSCHs using the HARQ-ACK codebook, the values of the counter-DAI fields of the DCI need to be arranged in ascending order, but when the counter-DAI field is omitted, the values of the counter-DAI field by explicit value can not be sorted in ascending order, and thus a method for determining the order of the HARQ-ACK bit in the HARQ-ACK codebook is required.

[0387] Therefore, a method of generating a HARQ-ACK codebook according to a predetermined standard even when some fields of the DCI are omitted will be described.

[0388] Figure 20 An example of a method for transmitting a HARQ-ACK for a PDSCH according to the order of reception of a PDCCH according to an embodiment of the disclosure will be described with reference to FIG. 12.

[0389] Referring to Figure 20 When some of the DAI fields are omitted or the size is set to 0 bits, the UE can generate a HARQ-ACK codebook according to the order in which the PDCCH for scheduling the PDSCH is received, not the counter-DAI value.

[0390] In the first embodiment of the disclosure, the UE can determine the order of the HARQ-ACK bits for the PDSCHs in the HARQ-ACK codebook based on time information of receiving the PDCCHs for scheduling the PDSCHs. That is, the UE can determine the order of the HARQ-ACK bits included in the HARQ-ACK codebook according to the order of receiving the PDCCHs regardless of the values of the counter-DAI in the PDCCHs transmitted for scheduling the PDSCHs.

[0391] For example, when the starting symbol of the CORESET including the PDCCH for scheduling the first PDSCH or the search space thereof is located before the starting symbol of the CORESET including the PDCCH for scheduling the second PDSCH or the search space thereof as shown in (a) of FIG. 11, in the HARQ-ACK codebook, B(1) as the HARQ-ACK bit for the first PDSCH can be arranged at a position before B(0) as the HARQ-ACK bit for the second PDSCH as shown in (b) of FIG. 11. Figure 20 Figure 20 For example, when the starting symbol of the CORESET including the PDCCH for scheduling the first PDSCH or the search space thereof is located before the starting symbol of the CORESET including the PDCCH for scheduling the second PDSCH or the search space thereof as shown in (a) of FIG. 11, in the HARQ-ACK codebook, B(1) as the HARQ-ACK bit for the first PDSCH can be arranged at a position before B(0) as the HARQ-ACK bit for the second PDSCH as shown in (b) of FIG. 11.

[0392] Figure 21 FIG. 11 illustrates an example of a method for transmitting HARQ-ACK for PDSCHs according to time information about the PDSCHs according to an embodiment of the disclosure.

[0393] Referring to FIG. 10, Figure 21 When some of the DAI fields are omitted or the size is set to 0 bits, the UE can generate the HARQ-ACK codebook according to time information about the PDSCHs included in the PDCCHs for scheduling the PDSCHs rather than the counter-DAI values.

[0394] In the second embodiment of the disclosure, the UE can determine the order of the HARQ-ACK bits for the PDSCHs constituting the HARQ-ACK codebook according to time information about the PDSCHs. Specifically, when the starting symbol of the first PDSCH is located before the starting symbol of the second PDSCH, in the HARQ-ACK codebook, the position of the HARQ-ACK bit for the first PDSCH can be before the position of the HARQ-ACK for the second PDSCH.

[0395] For example, as shown in (a) of FIG. 12, when the starting symbol of the CORESET including the PDCCH for scheduling the first PDSCH or the search space thereof is located before the starting symbol of the CORESET including the PDCCH for scheduling the second PDSCH or the search space thereof, in the HARQ-ACK codebook, B(1) as the HARQ-ACK bit for the first PDSCH can be arranged at a position before B(0) as the HARQ-ACK bit for the second PDSCH as shown in (b) of FIG. 12. Figure 21 ​As shown in (a) of FIG. 11, based on time information included in a PDCCH for scheduling a first PDSCH and time information included in a PDCCH for scheduling a second PDSCH, a starting symbol of the second PDSCH can be positioned before a starting symbol of the first PDSCH. In this case, as shown in (b) of FIG. 11, in a case where the UE transmits HARQ-ACK for the first PDSCH and HARQ-ACK for the second PDSCH through a PUCCH, B(1) which is a HARQ-ACK bit of the second PDSCH can be positioned before B(0) which is a HARQ-ACK bit of the first PDSCH. Figure 21 As shown in (a) of FIG. 11, based on time information included in a PDCCH for scheduling a first PDSCH and time information included in a PDCCH for scheduling a second PDSCH, a starting symbol of the second PDSCH can be positioned before a starting symbol of the first PDSCH. In this case, as shown in (b) of FIG. 11, in a case where the UE transmits HARQ-ACK for the first PDSCH and HARQ-ACK for the second PDSCH through a PUCCH, B(1) which is a HARQ-ACK bit of the second PDSCH can be positioned before B(0) which is a HARQ-ACK bit of the first PDSCH.

[0396] Figure 22 FIG. 11 illustrates an example of a method of transmitting HARQ-ACK for a PDSCH according to a HARQ process ID (or HARQ process number) of a PDCCH for scheduling the PDSCH according to an embodiment of the disclosure.

[0397] Referring to FIG. 11, Figure 22 When some of the DAI fields are omitted or the size is set to 0 bits, the UE can generate a HARQ-ACK codebook according to a HARQ process ID (or HARQ process number) included in a PDCCH for scheduling a PDSCH rather than a counter-DAI value.

[0398] In a third embodiment of the disclosure, the UE can determine the order of HARQ-ACK bits in a HARQ-ACK codebook according to the value of a HARQ process ID (or HARQ process number) of a PDCCH for scheduling a PDSCH.

[0399] Specifically, when a HARQ process ID of a first PDSCH in a PDCCH for scheduling the first PDSCH is A and a HARQ process ID of a second PDSCH in a PDCCH for scheduling the second PDSCH is B, in a HARQ-ACK codebook, a HARQ-ACK bit of a PDSCH having a smaller value among the A and B values can be arranged before a HARQ-ACK bit of a PDSCH having a larger value.

[0400] That is, the position of a HARQ-ACK bit can be determined according to an ascending order of a HARQ process ID. Here, the UE can assume that HARQ process IDs of HARQ-ACKs transmitted with one HARQ-ACK codebook have different values from each other. Therefore, it is not expected to generate one HARQ-ACK codebook having HARQ-ACK bits of PDSCHs having the same HARQ process ID.

[0401] For example, when the number of bits of the counter-DAI field included in at least one of the PDCCH for scheduling the first PDSCH and the PDCCH for scheduling the second PDSCH is different or is omitted, or is set to 0 bits, the UE can generate a HARQ-ACK codebook based on the HARQ-ACK process ID included in the PDCCH for scheduling each PDSCH, and transmit it to the base station through UCI.

[0402] In this case, as shown in (a) of FIG. 13, Figure 22 The value of the HARQ-ACK process ID or the HARQ-ACK process number of the PDCCH for scheduling the second PDSCH can be "0", and the value of the HARQ-ACK process ID or the HARQ-ACK process number of the PDCCH for scheduling the first PDSCH can be "1". In this case, as shown in (b) of FIG. 13, based on the ascending order of the HARQ-ACK process ID or the HARQ-ACK process number, B(0), which is the HARQ-ACK bit for the second PDSCH having a lower HARQ-ACK process ID or HARQ-ACK process number, can be positioned before B(1), which is the HARQ-ACK bit for the first PDSCH. Figure 15

[0403] In a fourth embodiment of the disclosure, the UE can determine the order of the HARQ-ACK bits of the PDSCHs in the HARQ-ACK codebook by using the cell information about the received PDCCH for scheduling each PDSCH. The cell information can refer to the index (or ID) of the cell. The UE can be configured to monitor the PDCCH in multiple cells. In this case, the UE can receive different PDCCHs in different cells. The UE can arrange the HARQ-ACK bits of the PDSCHs received in different cells in the HARQ-ACK codebook in ascending order of the index of the cell in which the PDCCH for scheduling the PDSCH has been received.

[0404] In a fifth embodiment of the disclosure, the UE can determine the order of the HARQ-ACK bits of the PDSCHs by using information about the CORESET (or search space) in which the PDCCH for scheduling the PDSCH has been received, to generate a HARQ-ACK codebook. Here, the information about the CORESET (or search space) can be the index (or ID) of the CORESET (or search space).

[0405] ​The UE can be configured to monitor PDCCH in multiple CORESETs (or search spaces). In this case, the UE can receive different PDCCHs in different CORESETs (or search spaces). In this case, the UE can arrange the order of HARQ-ACK bits of PDSCHs received in different CORESETs (or search spaces) in ascending order of the index of a CORESET (or search space) in which a PDCCH for scheduling a PDSCH has been received, to generate a HARQ-ACK codebook.

[0406] In the sixth embodiment of the present disclosure, the UE can determine the order of HARQ-ACK bits of PDSCHs in a HARQ-ACK codebook by using frequency domain information about a PDCCH for scheduling a PDSCH. Here, the frequency domain information can be the lowest PRB index among PRBs to which the PDCCH is allocated. Here, the index indicates a common PRB index, and the index indicates how far away from point A in the frequency domain. Point A indicates a reference frequency of the UE in the initial access procedure, and the specific point A is as follows.

[0407] -offsetToPointA indicates the frequency offset between point A and the lowest subcarrier of the lowest resource block. The lowest resource block has a subcarrier spacing provided by the higher layer parameter subCarrierSpacingCommon and overlaps with the SS / PBCH block used by the UE for initial cell selection. OffsetToPointA is expressed in units of resource blocks, assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2.

[0408] -absoluteFrequencyPointA indicates the frequency location of point A as an absolute radio frequency channel number (ARFCN) for all other cases.

[0409] The UE can be configured to monitor multiple PDCCHs, and can receive different PDCCHs in different frequency domains. In this case, the UE can arrange the HARQ-ACK bits of PDSCHs received in different frequency domains in the HARQ-ACK codebook in ascending order of the lowest PRB index of a PDCCH for scheduling a PDSCH. In this method, when the UE receives multiple PDCCHs in one CORESET (or search space) in the fifth embodiment, the order of HARQ-ACK bits in the HARQ-ACK codebook can be determined.

[0410] The first to sixth embodiments can be used in combination with each other, by which the UE can determine the order of the HARQ-ACK bits for the respective PDSCHs in the HARQ-ACK codebook. For example, the first and third embodiments can be combined. With this combination, the order of the HARQ-ACK bits in the HARQ-ACK codebook can be first determined according to the time domain information on the PDCCH, and when the order is not determined by the time domain information, the order can be determined according to the HARQ process ID of the third embodiment. Or, the first, fourth, fifth, and sixth embodiments can be combined. With this combination, the order of the HARQ-ACK bits in the HARQ-ACK codebook can be first determined according to the time domain information on the PDCCH. Then, when the order cannot be determined according to each embodiment by the time domain information, the order is determined according to the cell information, and when the order cannot be determined by the cell information, the order is determined according to the information on the CORESET (or search space). In addition, when the order cannot be determined with the information on the CORESET (or search space), the order can be determined according to the frequency domain allocation information on the PDCCH.

[0411] Further, in another embodiment of the disclosure, when each PDSCH is scheduled by a plurality of PDCCHs and the number of bits of the counter-DAI field included in the plurality of PDCCHs are different from each other, the UE can generate each HARQ-ACK codebook individually according to the number of bits of the counter-DAI, without multiplexing according to the number of bits.

[0412] For example, when the number of bits of the counter-DAI field is 2 bits or 1 bit, the UE can generate each of the HARQ-ACK codebook for the PDSCH scheduled by the PDCCH including the counter-DAI having the number of bits of 2 bits and / or the HARQ-ACK codebook for the PDSCH scheduled by the PDCCH including the counter-DAI having the number of bits of 1 bit individually, and transmit them to the base station.

[0413] That is, for the UE, one HARQ-ACK codebook can include only the HARQ-ACKs for the PDSCHs scheduled with the DCI format having the same number of bits of the counter-DAI.

[0414] With the first to sixth embodiments described above, the UE can determine the position of the HARQ-ACK bits in the HARQ-ACK codebook without the counter-DAI field. However, when generating the HARQ-ACK codebook including the HARQ-ACK bits for each PDSCH, a problem can occur when the UE determines the size of the HARQ-ACK codebook.

[0415] For example, when the UE does not receive one of the PDCCHs, the UE can determine the size of the HARQ-ACK codebook differently due to not receiving the PDCCH, and thus a method for solving this problem is needed.

[0416] In this case, the UE can always assume that the remainder is Y when the size of the dynamic HARQ-ACK codebook is divided by X. It is desirable that X = 4 and Y = 1. That is, the size of the dynamic HARQ-ACK codebook can be determined to be one of 1, 5, 9,... bits. When the UE receives a PDCCH for scheduling Z PDSCHs, the UE can determine the minimum value among the sizes that are greater than or equal to Z as the size of the HARQ-ACK codebook. For example, if Z = 3, 5 can be determined as the size of the HARQ-ACK codebook.

[0417] The counter-DAI field can be included in the DCI of the PDCCH corresponding to the HARQ-ACK of one HARQ-ACK codebook, and can not be included therein. In this case, in the HARQ-ACK codebook, the UE determines the positions of the HARQ-ACKs of the PDSCHs scheduled by the DCI including the counter-DAI field and the PDSCHs scheduled by the DCI without the counter-DAI field.

[0418] In an embodiment of the disclosure, in this case, the UE can generate each HARQ-ACK codebook separately according to whether the DCI includes the counter-DAI field.

[0419] Specifically, the UE generates a first sub-HARQ-ACK codebook by collecting only the HARQ-ACKs of the PDSCHs scheduled by the DCI including the counter-DAI field. In this case, the positions of the HARQ-ACKs in the first sub-HARQ-ACK codebook are determined by using the values of the counter-DAI field (that is, the positions are determined in ascending order according to the counter-DAI). In this case, when 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 combinations thereof can be used.

[0420] Further, the UE generates a second sub-HARQ-ACK codebook by collecting HARQ-ACKs of only PDSCHs scheduled by DCI in which the counter-DAI field is omitted or set to a 0-bit value. In this case, the positions of HARQ-ACKs in the second sub-HARQ-ACK codebook can be determined according to the first to sixth embodiments described above and combinations thereof. The UE can continuously combine the first sub-HARQ-ACK codebook and the second sub-HARQ-ACK codebook (i.e., such that the first bit of the second sub-HARQ-ACK codebook appears after the last bit of the first sub-HARQ-ACK codebook) to generate a HARQ-ACK codebook. In this method, the UE needs to generate two sub-HARQ-ACK codebooks in different ways, and the UE complexity can accordingly increase.

[0421] In another embodiment of the disclosure, in the above case, the UE can ignore the counter-DAI field included in the DCI. That is, by regarding all DCIs as DCIs having no counter-DAI field, the positions of HARQ-ACK bits in the HARQ-ACK codebook can be determined by using the first to sixth embodiments and combinations thereof.

[0422] In another embodiment of the disclosure, the UE configured with the semi-static HARQ-ACK codebook can determine a HARQ-ACK bit for one PDSCH.

[0423] Specifically, the UE configured with the semi-static HARQ-ACK codebook needs to transmit a HARQ-ACK codebook including a predetermined number of HARQ-ACK bits through a PUCCH. In this case, the predetermined number can be determined regardless of which PDSCH the UE actually schedules, and can be derived from information set to a higher layer.

[0424] The information set to the higher layer can include at least CBG configuration information of a cell, and the UE can receive the CBG configuration information for each cell. The CGB configuration information can be used to configure the maximum number of CBGs that one PDSCH (or TB) can include, and can be denoted as N MAX In the semi-static HARQ-ACK codebook, when including HARQ-ACK bits of PDSCHs, it is necessary to determine how many HARQ-ACK bits one PDSCH corresponds to. In general, when CBG transmission is not configured, the PDSCH can correspond to 1-bit HARQ-ACK (2 bits when 2-TB transmission is configured), and when CBG transmission is configured, the PDSCH can correspond to N MAX bits of HARQ-ACK.

[0425] When the UE is configured with semi-static HARQ-ACK, the number of HARQ-ACK bits determined above needs to be included in the PUCCH. Even if CBG-based transmission is configured, in certain cases, the UE can transmit only 1-bit HARQ-ACK for PDSCH by including it in the PUCCH.

[0426] For example, when one downlink cell (or carrier) is configured in the UE while at least one of the following cases is satisfied, and when there is one monitoring occasion for receiving PDCCH, the UE can generate only 1-bit HARQ-ACK for SPS PDSCH or SPS PDSCH release DCI or PDSCH, while CBG-based transmission is configured.

[0427] - When the UE needs to transmit HARQ-ACK for one SPS PDSCH

[0428] - When one SPS PDSCH release DCI is received

[0429] - When HARQ-ACK for PDSCH scheduled with DCI format 1_0 or DCI format 1_2 is transmitted

[0430] That is, even if CBG-based transmission is configured, the UE can generate only 1-bit HARQ-ACK per PDSCH.

[0431] In contrast, when CBG-based transmission is configured, and when 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 occasions for receiving PDCCH, the UE can generate N MAX bits by repeating 1-bit HARQ-ACK (TB-level HARQ-ACK) for SPS PDSCH or SPS PDSCH release DCI or PDSCH. MAX

[0432] - When HARQ-ACK for one SPS PDSCH is transmitted

[0433] - When one SPS PDSCH release DCI is received

[0434] - When HARQ-ACK for PDSCH scheduled with DCI format 1_0 or DCI format 1_2 is transmitted

[0435] That is, according to CBG-based transmission, the UE can generate N MAX bits of HARQ-ACK per PDSCH.

[0436] ​In the above operation, the DCI format 1_2 is a DCI format in which the size of each field can be set to obtain high reliability and low latency. Such a DCI format 1_2 does not support CBG-based operation. That is, the PDSCH scheduled with the DCI format 1_2 always corresponds to 1 bit of TB-level HARQ-ACK. This is similar to the DCI format 1_0. Accordingly, the DCI format 1_2 can be handled in the same manner as the DCI format 1_0.

[0437] Figure 23 is a flowchart illustrating an example of an operation of a UE transmitting HARQ-ACK based on downlink information having different formats according to an embodiment of the disclosure.

[0438] Referring to Figure 23 , the UE can generate a HARQ-ACK codebook including HARQ-ACK bits for a plurality of PDSCHs scheduled by DCIs transmitted on a plurality of PDCCHs from a base station. In this case, when the formats of the DCIs are different and the number of bits of the DAI field included in each of the DCIs is different, the UE can interpret the value of the DAI field under certain conditions to generate the HARQ-ACK codebook.

[0439] First, the UE receives a first PDCCH for scheduling a first downlink physical shared channel (PDSCH) (S23010). In this case, the UE can receive setting information including information for receiving the PDCCH before receiving the first PDCCH.

[0440] The first PDCCH can include a first counter downlink assignment indicator (DAI) indicating the number of scheduled PDSCHs until the time point of monitoring the first PDCCH and a first total DAI indicating the number of all PDSCHs scheduled in a serving cell.

[0441] Then, the UE receives a second PDCCH for scheduling a second PDSCH, the second PDCCH including a second counter DAI and a second total DAI (S23020).

[0442] Then, the UE receives the first PDSCH based on the first PDCCH (S23030) and receives the second PDSCH based on the second PDCCH (S23040).

[0443] After receiving the first PDSCH and the second PDSCH, the UE generates a HARQ-ACK bit for each of the first PDSCH and the second PDSCH, and generates a HARQ-ACK codebook by using the generated HARQ-ACK bits.

[0444] Then, the UE transmits uplink control information (UCI) including a HARQ-ACK codebook to the base station (S23050).

[0445] 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 can be identified based on the number of bits of the first counter DAI. That is, when the number of bits of the first counter DAI is different from the number of bits of the second counter DAI, the UE can generate a HARQ-ACK codebook including HARQ-ACK bits by the methods of the above proposals 1 to 3.

[0446] For example, when 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 can be identified based on at least one of the bits among the bits of the second counter DAI, the number of which is equal to the number of bits of the first counter DAI.

[0447] Alternatively, when 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 can be interpreted 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.

[0448] In this case, when there are a plurality of candidate values of the second counter DAI, the value of the second counter DAI can be interpreted as a value having the smallest difference from the value indicated by the first counter DAI among the plurality of candidate values.

[0449] Figure 24 is a flowchart illustrating an example of an operation of a base station receiving HARQ-ACK based on downlink information having different formats according to an embodiment of the disclosure.

[0450] Referring to Figure 24 , the base station can schedule PDSCHs to the UE through a plurality of PDCCHs having different formats. In this case, when the number of bits of the DAI field included in the DCI of the different formats on the PDCCHs is different, the base station can receive a HARQ-ACK codebook for the PDSCHs scheduled by the DCI of the different formats from the UE.

[0451] First, the base station transmits a first PDCCH for scheduling a first downlink physical shared channel (PDSCH) to the UE (S24010). In this case, the base station can transmit setting information including information for receiving the PDCCH before transmitting the first PDCCH.

[0452] The first PDCCH can include a first counter downlink assignment indicator (DAI) indicating a number of scheduled PDSCHs until a time point of monitoring the first PDCCH and a first total DAI indicating a number of all PDSCHs scheduled in a serving cell.

[0453] Then, the base station transmits a second PDCCH for scheduling a second PDSCH, the second PDCCH including a second counter DAI and a second total DAI (S24020).

[0454] Then, the base station transmits the first PDSCH based on the first PDCCH (S24030) and transmits the second PDSCH based on the second PDCCH (S24040).

[0455] The base station receives, from the UE, a HARQ-ACK codebook including a HARQ-ACK bit for each of the first PDSCH and the second PDSCH generated by the UE through uplink control information (UCI) (S24050).

[0456] When the number of bits of the first counter DAI is different from the number of bits of the second counter DAI, the value indicated by the second counter DAI can be identified based on at least one of the number of bits of the second counter DAI equal to the number of bits of the first counter DAI. That is, when the number of bits of the first counter DAI is different from the number of bits of the second counter DAI, the UE can generate a HARQ-ACK codebook including a HARQ-ACK bit by the methods of the above proposals 1 to 3.

[0457] For example, when the number of bits of the first counter DAI is less than the number of bits of the second counter DAI, the value indicated by the second counter DAI can be identified based on at least one of the number of bits of the second counter DAI equal to the number of bits of the first counter DAI.

[0458] Alternatively, when 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 can be interpreted 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.

[0459] In this case, when there are a plurality of candidate values of the second counter DAI, the second counter DAI value can be interpreted as a value having the smallest difference from the value indicated by the first counter DAI among the plurality of candidate values.

[0460] The above description of the present disclosure is for the purpose of illustration, and it is understood by those of ordinary skill in the art to which the present disclosure pertains that the present disclosure can be easily modified in other specific forms without changing the technical spirit or essential characteristics of the present disclosure. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and are not restrictive. For example, each component described as a single type can be implemented in a distributed manner, and similarly, components described as distributed can also be implemented in a combined form.

[0461] The scope of the present disclosure is represented by the claims to be described below, not the above detailed description, and it is to be explained that the meaning and scope of the claims and all changes or modifications derived from equivalents thereof fall within the scope of the present disclosure.

Claims

1. A user equipment for use in a wireless communication system, the user equipment comprising: a communication module; and a processor configured to control the communication module, wherein the processor is configured to receive a plurality of first downlink control information (DCI) formats for downlink scheduling, wherein the downlink scheduling comprises physical downlink shared channel (PDSCH) scheduling, and each of the plurality of first DCI formats comprises a Nc-bit counter downlink assignment index (c-DAI), and Nc is one of 1 and 2; receive a second DCI format for scheduling a physical uplink shared channel (PUSCH), wherein the second DCI format comprises a 2-bit uplink DAI (UL-DAI); and transmit a hybrid automatic repeat request (HARQ) acknowledgement (ACK) codebook for the downlink scheduling via the PUSCH, wherein a bit size of the HARQ-ACK codebook is associated with O, which has a value of: i) a first value: 4*floor(j*C / 4)+V, or ii) a second value, which is 4 larger than the first value, wherein j is a counter value for a case where a value of a Nc-bit c-DAI among a plurality of received Nc-bit c-DAIs is less than or equal to a value of a previous Nc-bit c-DAI, V is a value of the 2-bit UL-DAI, and is in a range of 1 to 4, and - C is 2 Nc , floor is a floor function. Nc is 1.

2. The user equipment of claim 1, wherein, the bit size of the HARQ-ACK codebook is determined as O or P*O, and P is a positive integer.

3. The user equipment of claim 1, wherein, a value of a last one of the plurality of received Nc-bit c-DAIs and the converted 2-bit c-DAI value satisfy a relation comprising the following table:

4. The user equipment of claim 1, wherein, Q has the second value only when V is less than V temp and Q has the second value only when V is less than V wherein, when Nc is 1, V temp determining a 2-bit c-DAI value converted from a value of a last one of the plurality of received Nc-bit c-DAIs, such that the converted 2-bit c-DAI value corresponds to the number of downlink schedules determined based on the plurality of received Nc-bit c-DAIs.

5. The user equipment of claim 4, wherein, wherein X denotes the value of the last one of the plurality of received Nc-bit c-DAIs, and Y denotes the converted 2-bit c-DAI value. the Nc-bit c-DAIs are associated with bit positions of corresponding HARQ-ACK information in the HARQ-ACK codebook.

6. The user equipment of claim 1, wherein, the Nc-bit c-DAIs are related to counter numbers of corresponding downlink scheduling, and the 2-bit UL DAI is related to a total number of the downlink scheduling.

7. The user equipment of claim 1, wherein, the wireless communication system comprises a third generation partnership project (3GPP) based wireless communication system.

8. The user equipment of claim 1, wherein, 9.A method performed by a user equipment in a wireless communication system, the method comprising: receiving a plurality of first downlink control information (DCI) formats for downlink scheduling, wherein the downlink scheduling comprises physical downlink shared channel (PDSCH) scheduling, and each of the plurality of first DCI formats comprises a Nc-bit counter downlink assignment index (c-DAI), and Nc is one of 1 and 2; receiving a second DCI format for scheduling a physical uplink shared channel (PUSCH), wherein the second DCI format comprises a 2-bit uplink DAI (UL-DAI); and transmitting a hybrid automatic repeat request (HARQ) acknowledgement (ACK) codebook for the downlink scheduling via the PUSCH, transmitting a hybrid automatic repeat request (HARQ) acknowledgement (ACK) codebook for the downlink scheduling via the PUSCH, wherein a bit size of the HARQ-ACK codebook is associated with O, the O having a value of: i) a first value: 4*floor(j*C / 4)+V, or ii) a second value, the second value being 4 greater than the first value, wherein j is a counter value for a case where a value of an Nc-bit c-DAI among a plurality of received Nc-bit c-DAIs is less than or equal to a value of a previous Nc-bit c-DAI, - C is 2 Nc , V is a value of the 2-bit UL-DAI, and is in a range of 1 to 4, and floor is a down-rounding function.

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

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

12. The method of claim 9, wherein, Q has the second value only when V is less than V temp and Q has the second value only when V is less than V wherein, when Nc is 1, V temp determining a 2-bit c-DAI value converted from a value of a last one of the plurality of received Nc-bit c-DAIs, such that the converted 2-bit c-DAI value corresponds to the number of downlink schedules determined based on the plurality of received Nc-bit c-DAIs.

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

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

15. The method of claim 9, wherein, the Nc-bit c-DAI is related to a counter number of corresponding downlink scheduling, and the 2-bit UL DAI is related to a total number of the downlink scheduling.

16. The method of claim 9, wherein, the wireless communication system comprises a third generation partnership project (3GPP) based wireless communication system.

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