Method, device and system for downlink data reception and HARQ-ACK transmission in wireless communication system

Abstract

The present invention relates to a method, apparatus, and system for downlink reception and HARQ-ACK transmission in a wireless communication system. According to the present disclosure, in the method, apparatus, and system 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 hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebooks for the first and second PDSCHs is sent to a base station.

Description

[0001] This application is a divisional application of the patent application with the international application date of May 4, 2020, application number 202080042075.X (PCT / KR2020 / 005923) submitted to the China Patent Office on December 7, 2021, and the invention name is "Method, device and system for downlink data reception and HARQ-ACK transmission in a wireless communication system". Technical Field

[0002] The present disclosure relates to a wireless communication system, and more particularly, to transmission of downlink data and transmission of a response thereto in the wireless communication system. Background Art

[0003] 3GPP LTE(-A) defines uplink and downlink physical channels for transmitting physical layer signals. For example, it defines the Physical Uplink Shared Channel (PUSCH) as a physical channel for transmitting uplink data, the Physical Uplink Control Channel (PUCCH) for transmitting control signals, and the Physical Random Access Channel (PRACH). Furthermore, it defines the Physical Downlink Shared Channel (PDSCH) for transmitting downlink data, and the Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH), and Physical Hybrid ARQ Indicator Channel (PHICH) for transmitting L1 / L2 control signals.

[0004] The downlink control channel (PDCCH / EPDCCH) among the above channels is a channel used by the base station to send uplink / downlink scheduling allocation control information, uplink transmit power control information and other control information to one or more user equipment. Since the resources available for the PDCCH that can be sent by the base station at one time are limited, different resources cannot be allocated to each user equipment, and control information should be sent to any user equipment through shared 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, the user equipment can be notified of the resources that can combine and transmit one or more CCEs, and multiple user equipment can share and use CCEs. Here, the number of combined CCEs is called the CCE combination level, and the resources to which CCEs are allocated according to the possible CCE combination levels are called search spaces. The search space may 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 the user equipment (UE) identifier included in the PDCCH. Therefore, this operation of the user equipment takes a long time to decode the PDCCH and inevitably leads to a large amount of energy consumption.

[0005] Efforts are underway to develop an improved 5G communication system or pre-5G communication system to meet the growing demand for wireless data services after the commercialization of the 4G communication system. For this reason, the 5G communication system or pre-5G communication system is referred to as a super-4G network communication system or a post-LTE system. Consider implementing a 5G communication system in an ultra-high frequency (mmWave) band (e.g., a 60-GHz band) to achieve high data transmission rates. In order to reduce radio propagation path loss and increase the transmission distance of radio waves in the ultra-high frequency band, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed in the field of 5G communication systems. Furthermore, in order to improve the network 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, collaborative communications, coordinated multi-point (CoMP), interference cancellation, etc. have been developed in the field of 5G communication systems. In addition, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) schemes, as well as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies have been developed in the field of 5G systems.

[0006] At the same time, the Internet, a human-centric connected network where humans generate and consume information, has evolved into the Internet of Things (IoT) network, which exchanges information between distributed components such as objects. The Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology through connection to cloud servers, is also emerging. Implementing the IoT requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology. Consequently, in recent years, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) have been studied to connect objects. Within the IoT environment, intelligent Internet technology (IT) services can be provided that collect and analyze data generated by networked objects to create new value in human life. Through the integration and hybridization of existing information technology (IT) and various industries, the IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and advanced medical services.

[0007] Various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communications (MTC) are being implemented using 5G communication technologies (i.e., beamforming, MIMO, array antennas, etc.). The application of cloud radio access networks (cloud RAN) as a big data processing technology is an example of the convergence of 5G and IoT technologies.

[0008] Mobile communication systems have traditionally been developed to provide voice services while protecting user activity. However, the scope of mobile communication systems has expanded beyond voice services to include data services, and has even been developed to provide high-speed data services. However, current mobile communication systems for providing these services are experiencing resource shortages, and users are demanding higher-speed services. Therefore, a more advanced wireless communication system is needed.

[0009] As mentioned above, with the emergence of new applications such as real-time control and tactile Internet, future 5G technology requires lower data transmission latency, and it is expected that the required latency of 5G data will be reduced to 1ms. The goal of 5G is to provide data latency that is approximately 10 times lower than that of existing technologies. To address this problem, it is expected to propose a 5G communication system that uses micro slots with shorter TTI intervals (e.g., 0.2ms) in addition to existing time slots (or subframes).

[0010] In Rel-16 enhanced URLLC (eURLLC), various technologies for providing lower latency and higher reliability are discussed. To provide even lower latency, support is provided for the transmission of uplink control channels that include two or more HARQ-ACKs in a single time slot. User equipment can send HARQ-ACKs as quickly as possible in response to successful reception of a downlink shared channel, thereby ensuring lower latency. Summary of the Invention

[0011] Technical issues

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

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

[0014] Technical Solution

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

[0016] In addition, in the present disclosure, 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 is determined based on at least one of the bits of the second counter DAI whose number is equal to the number of bits of the first counter DAI.

[0017] In addition, in the present disclosure, when there are multiple 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 the value among the multiple values ​​that has the smallest difference with the value indicated by the first counter DAI.

[0018] In addition, in the present 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 the least significant bit (LSB) or the most significant bit (MSB) of the 2 bits.

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

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

[0021] In addition, in the present disclosure, 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 is determined by extending the number of bits of the second counter DAI to the same number of bits as the first counter DAI.

[0022] Furthermore, in the present disclosure, when there are a plurality of second counter DAI values ​​determined by being extended to the same number of bits as that of the first counter DAI, it is determined that the value of the second counter DAI is a value having the smallest difference from the value indicated by the first counter DAI among the plurality of values.

[0023] Furthermore, in the present 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] In addition, in the present disclosure, when 2 bits of the first counter DAI are "00" or "01" and 1 bit of the second counter DAI is "0", the second counter DAI is determined to be "3", and when 2 bits of the first counter DAI are "10" or "11" and 1 bit of the second counter DAI is "1", the second counter DAI is determined to be "1".

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

[0026] In addition, the present 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 the number of scheduled PDSCHs of the serving cell until the time point of monitoring the first PDCCH and a first total DAI indicating the number of all PDSCHs scheduled in the serving cell until 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 sending uplink control information (UCI) including a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebook for the first PDSCH and the second PDSCH to the base station, wherein, when the number of bits of the first counter DAI is different from the number of bits of the second counter DAI, the value of the second counter DAI is determined based on the number of bits of the first counter DAI.

[0027] Beneficial effects

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

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

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

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

[0032] Effects obtainable from the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 An example of a radio frame structure used in a wireless communication system is illustrated.

[0034] Figure 2 An example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system is illustrated.

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

[0036] Figure 4 Illustration of SS / PBCH blocks used for initial cell access in a 3GPP NR system.

[0037] Figure 5 Illustration of a process for transmitting control information and control channels in a 3GPP NR system.

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

[0039] Figure 7 A method for configuring a PDCCH search space in a 3GPP NR system is illustrated.

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

[0041] Figure 9 It 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 technology 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 embodiments of the present disclosure are applicable.

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

[0046] Figure 14 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 is illustrated.

[0047] Figure 15 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 is illustrated.

[0048] Figure 16 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 is illustrated.

[0049] Figure 17 An example of a downlink assignment indicator for each piece of downlink control information detected in a monitoring opportunity according to an embodiment of the present disclosure is illustrated.

[0050] Figure 18 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 is illustrated.

[0051] Figure 19 An example of a downlink assignment indicator for each piece of downlink control information detected in a monitoring opportunity according to an embodiment of the present disclosure is illustrated.

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

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

[0054] Figure 22 FIG. 1 illustrates 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 present disclosure.

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

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

[0057] The terms used in this specification are generally used, as much as possible, based on the functions of the present invention. However, these terms may be changed according to the intentions, customs, and new technologies of those skilled in the art. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in such cases, their meanings will be described in the corresponding description of the present invention. Therefore, it is intended that the terms used in this specification should not be analyzed based solely on the name of the term, but should be analyzed based on the substantive meaning of the term and content throughout the specification.

[0058] Throughout the specification and the claims that follow, when it is described that an element is “connected” to another element, the element may be “directly connected” to the other element or “electrically connected” to the other element through a third element. In addition, unless explicitly described to the contrary, the word “include” will be understood to imply the inclusion of the elements stated and not the exclusion of any other elements. Furthermore, in some exemplary embodiments, limitations such as “greater than or equal to” or “less than or equal to” based on a specific threshold value may be appropriately replaced with “greater than” or “less than”, respectively.

[0059] The following technologies can be used in various wireless access systems: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier-FDMA (SC-FDMA), etc. CDMA can be implemented by wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented by wireless technologies such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented by wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), etc. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using Evolved UMTS Terrestrial Radio Access (E-UTRA), and LTE Advanced (A) is an evolved version of 3GPP LTE. 3GPP New Radio (NR) is a system designed separately from LTE / LTE-A, and is a system for supporting enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine type communication (mMTC) services that are requirements of IMT-2020. For clarity of description, 3GPP NR is mainly described, but the technical idea of ​​the present invention is not limited thereto.

[0060] Unless otherwise specified in this specification, a base station may refer to a next-generation Node B (gNB) defined in 3GPP NR. Furthermore, unless otherwise specified, a terminal may refer to a user equipment (UE). Although specific embodiments are individually categorized into embodiments to aid understanding, these embodiments may be used in combination. In this disclosure, the configuration of a user equipment may refer to configuration by a base station. Specifically, a base station may send a signal to the user equipment to set parameter values ​​used in the operation of the user equipment or the wireless communication system.

[0061] Figure 1 An example of a radio frame structure used in a wireless communication system is illustrated.

[0062] refer to Figure 1 , the radio frame (or radio frame) used in the 3GPP NR system may have a 10ms (Δf max N f / 100)*T c ) length. In addition, the wireless frame consists of 10 subframes (SFs) of equal size. Here, Δf max =480*10 3 Hz, 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 assigned to 10 subframes within a radio frame. Each subframe is 1ms long and can include one or more time slots according to the subcarrier spacing. More specifically, in the 3GPP NR system, the subcarrier spacing that can be used is 15*2 μ kHz, and μ can have a value of μ=0 to 4 as a subcarrier spacing configuration. That is, 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz can be used for subcarrier spacing. One subframe with a length of 1ms can include 2 μ In this case, the length of each time slot is 2 -μ ms. It can be set from 0 to 2 μ -1 are assigned to the 2 μ In addition, the time slots from 0 to 10*2 μ Numbers of -1 are assigned to time slots within a radio frame, respectively. Time resources may be distinguished by at least one of a radio frame number (also referred to as a radio frame index), a subframe number (also referred to as a subframe index), and a time slot number (or time slot index).

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

[0064] There is one resource grid per antenna port. Figure 2 , a time slot includes multiple orthogonal frequency division multiplexing (OFDM) symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. An OFDM symbol also refers to a symbol interval. Unless otherwise specified, an OFDM symbol may be referred to as a symbol. An RB includes 12 consecutive subcarriers in the frequency domain. Reference Figure 2 , the signal transmitted from each time slot can be composed of N size,μ grid,x *N RB sc subcarriers and N slot symb Here, when the signal is a DL signal, x=DL, and when the signal is a UL signal, x=UL. N size,μ grid,xrepresents the number of resource blocks (RBs) according to the subcarrier spacing component μ (x is DL or UL), and N slot symb Indicates the number of OFDM symbols in a time slot. RB sc is the number of subcarriers constituting one RB and N RB sc = 12. The OFDM symbol may be called a cyclic shift OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol according to a multiple access scheme.

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

[0066] An RB can be composed of N in the frequency domain RB sc For reference, a resource configured with one OFDM symbol and one subcarrier is referred to as a resource element (RE) or tone. Thus, one RB can be configured with N slot symb *N RB sc resource elements. Each resource element in the resource grid can be uniquely defined by a pair of indices (k, l) in a time slot. k can be a value from 0 to N in the frequency domain. size,μ grid,x *N RB sc –1 is the assigned index, and l can be from 0 to N in the time domain slot symb –1 The assigned index.

[0067] In order for a UE to receive signals from or transmit signals to a base station, the UE's time / frequency may be synchronized with the base station's time / frequency. This is because when the base station and UE are synchronized, the UE can determine the time and frequency parameters necessary to demodulate the downlink signal and transmit the uplink signal at the correct time.

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

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

[0070] When the information about the symbol type is configured with a UE-specific RRC signal, the base station can signal whether the flexible symbol is a DL symbol or a UL symbol with a cell-specific RRC signal. In this case, the UE-specific RRC signal cannot change the DL symbol or UL symbol configured with the cell-specific RRC signal to another symbol type. The UE-specific RRC signal can signal the N of the corresponding time slot for each time slot. slot symb The number of DL symbols among the symbols and the N of the corresponding time slot slot symbThe number of UL symbols among the symbols. In this case, the DL symbols of the time slot can be continuously configured with the first symbol to the i-th symbol of the time slot. In addition, the UL symbols of the time slot can be continuously configured with the j-th symbol to the last symbol of the time slot (where i < j). In the time slot, the symbol that is not configured with any of the UL symbols and DL symbols is a flexible symbol.

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

[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 synchronize with the BS during the initial cell search. To this end, the UE can receive a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station, and obtain information such as the cell ID. Thereafter, the UE can receive a physical broadcast channel from the base station and obtain the broadcast information in the cell.

[0073] When the initial cell search is completed, the UE receives a physical downlink shared channel (PDSCH) according to the physical downlink control channel (PDCCH) and the information in the PDCCH, so that the UE can obtain more specific system information than the system information obtained through the initial cell search (S102). Here, the system information received by the user equipment is cell-common system information for the normal operation of the user equipment in the physical layer in 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 radio resources for signal transmission, the UE can perform a random access procedure (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 the PDCCH and the corresponding PDSCH (S104). When the UE receives a valid random access response message, the UE transmits data including the identifier of the UE, etc. to the base station through a physical uplink shared channel (PUSCH) indicated by a UL grant sent by the base station through the PDCCH (S105). Next, the UE waits for the reception of the PDCCH as an indication from the base station for conflict resolution. If the UE successfully receives the PDCCH (S106) through the identifier of the UE, the random access procedure is terminated. The user equipment can obtain terminal-specific system information required for the correct operation of the user equipment in the physical layer in the RRC layer during the random access procedure. When the user equipment obtains terminal-specific system information from the RRC layer, the user equipment enters the RRC connected mode.

[0075] The RRC layer is used to generate or manage messages between user equipment and the radio access network (RAN). More specifically, the base station and user equipment can perform, in the RRC layer, broadcasting cell system information required by all user equipment in the cell, managing the transmission of paging messages, mobility management, handover, user equipment measurement reporting and its control, and storage management including user equipment capability management and device management. Generally, since the update of the signal transmitted in the RRC layer (hereinafter referred to as the RRC signal) is longer than the transmission / reception period (i.e., transmission time interval (TTI)) in the physical layer, the RRC signal can be maintained and unchanged for a long period.

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

[0077] Figure 4 Illustration of SS / PBCH blocks used for initial cell access in a 3GPP NR system.

[0078] When the power is turned on or when the UE wants to access a new cell, it can obtain time and frequency synchronization with the cell and perform an initial cell search process. During the cell search process, the UE can detect the physical cell identity N of the cell. cell ID To this end, the UE may receive synchronization signals, such as a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), from the base station and synchronize with the base station. In this case, the UE may obtain information such as a cell identity (ID).

[0079] refer to Figure 4(a) of FIG. 1 , the synchronization signal (SS) will be described in more detail. The synchronization signal can be classified into PSS and SSS. PSS can be used to obtain time domain synchronization and / or frequency domain synchronization, such as OFDM symbol synchronization and time slot synchronization. SSS can be used to obtain frame synchronization and cell group ID. Figure 4 (a) 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 and the SSS is transmitted in the third OFDM symbol through the 56th to 182nd subcarriers. Here, the lowest subcarrier index of the SS / PBCH block is numbered from 0. In the first OFDM symbol in which the PSS is transmitted, the base station does not transmit signals through the remaining subcarriers, i.e., the 0th to 55th subcarriers and the 183rd to 239th subcarriers. In addition, in the third OFDM symbol in which the SSS is transmitted, the base station does not transmit signals through the 48th to 55th subcarriers and the 183rd to 191st subcarriers. The base station transmits the physical broadcast channel (PBCH) through the remaining REs in the SS / PBCH block except for the above signals.

[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 group including three unique identifiers, through a combination of three PSSs and SSSs, specifically so that each physical layer cell ID will be part of only one physical layer cell identifier group. cell ID =3N (1) ID +N (2) ID The physical layer cell identifier group can be indicated by an index N ranging from 0 to 335. (1) ID and an index N ranging from 0 to 2 indicating a physical layer identifier in the physical layer cell identifier group (2) ID Uniquely defined. The UE can detect the PSS and identify one of the three unique physical layer identifiers. In addition, the UE can detect the SSS and identify one of the 336 physical layer cell IDs associated with the physical layer identifier. In this case, the sequence d of the PSS PSS (n) as follows.

[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 of SSS SSS (n) as follows.

[0089] d SSS (n)=[1-2x0((n+m0)mod127)][1-2x1((n+m1)mod127)]

[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 10ms can be divided into two half-frames having a length of 5ms. Figure 4(b) of the Serial Number Protocol (SN) will describe the time slot in which the SS / PBCH block is transmitted in each half frame. The time slot in which the SS / PBCH block is transmitted may be any of Cases A, B, C, D, and E. In Case A, the subcarrier spacing is 15 kHz and the starting time point of the SS / PBCH block is the ({2, 8}+14*n)th symbol. In this case, at a carrier frequency of 3 GHz or lower, n=0 or 1. In addition, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n=0, 1, 2, 3 may be used. In Case B, the subcarrier spacing is 30 kHz and the starting time point of the SS / PBCH block is {4, 8, 16, 20}+28*n. In this case, at a carrier frequency of 3 GHz or lower, n=0. In addition, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n=0, 1 may be used. In Case C, the subcarrier spacing is 30 kHz and the starting time point of the SS / PBCH block is the ({2, 8}+14*n)th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0 or 1. In addition, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n can be 0, 1, 2, 3. In case D, the subcarrier spacing is 120 kHz and the starting time point of the SS / PBCH block is the ({4, 8, 16, 20} + 28 * n)th symbol. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In case E, the subcarrier spacing is 240 kHz and the starting time point of the SS / PBCH block is the ({8, 12, 16, 20, 32, 36, 40, 44} + 56 * n)th symbol. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0097] Figure 5 This figure illustrates the process of transmitting control information and control channels in the 3GPP NR system. Figure 5(a) The base station may add a cyclic redundancy check (CRC) masked (e.g., XORed) with a radio network temporary identifier (RNTI) to control information (e.g., downlink control information (DCI)) (S202). The base station may scramble the CRC with an RNTI value determined according to the purpose / target of each control information. The common RNTI used by one or more UEs can include at least one of a system information RNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI), and a transmit power control RNTI (TPC-RNTI). In addition, the UE-specific RNTI may include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, the base station may perform rate matching according to the amount of resources used for PDCCH transmission after performing channel coding (e.g., polarity coding) (S204) (S206). Thereafter, the base station may multiplex DCI based on a PDCCH structure based on control channel elements (CCEs) (S208). In addition, the base station may apply additional processes such as scrambling, modulation (e.g., QPSK), interleaving, etc. to the multiplexed DCI (S210), and then map the DCI to the resources to be transmitted. CCE is the basic resource unit for PDCCH, and one CCE may include multiple (e.g., six) resource element groups (REGs). One REG may be configured with multiple (e.g., 12) REs. The number of CCEs used for one PDCCH may be defined as an aggregation level. In a 3GPP NR system, aggregation levels of 1, 2, 4, 8, or 16 may be used. Figure 5 (b) is a diagram related to CCE aggregation levels and multiplexing of PDCCHs, and illustrates types of CCE aggregation levels for one PDCCH and CCEs transmitted in the control region accordingly.

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

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

[0100] Figure 7 FIG. 1 illustrates a method for setting a PDCCH search space in a 3GPP NR system.

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

[0102] For ease of explanation, a PDCCH that is scrambled with a group common (GC) RNTI previously known to a UE in order to transmit DL control information to one or more UEs is referred to as a group common (GC) PDCCH or a common PDCCH. Furthermore, a PDCCH that is scrambled with the RNTI of a specific terminal already known to a specific UE in order to transmit UL scheduling information or DL ​​scheduling information to a specific UE is referred to as a UE-specific PDCCH. A common PDCCH may be included in a common search space, and a UE-specific PDCCH may be included in a common search space or a UE-specific PDCCH.

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

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

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

[0108] The PUCCH may 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 the PDCCH (indicating a DL SPS release) and / or a response to a DL transport block (TB) on the PDSCH. HARQ-ACK indicates whether the information sent on the PDCCH or PDSCH is received. The HARQ-ACK response includes a positive ACK (abbreviated as ACK), a negative ACK (hereinafter referred to as NACK), a discontinuous transmission (DTX), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK / NACK and ACK / NACK. Generally, ACK can be represented by a bit value of 1, while NACK can be represented by a bit value of 0.

[0111] Channel State Information (CSI): Feedback information about the DL channel. The UE generates this information based on the CSI-Reference Signal (RS) transmitted by the base station. Multiple-Input Multiple-Output (MIMO)-related feedback information includes the Rank Indicator (RI) and the Precoding Matrix Indicator (PMI). The CSI can be divided into CSI Part 1 and CSI Part 2 based on the information indicated by the CSI.

[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 the time axis and one PRB on the 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 that is cyclically shifted (CS) from the basic sequence used in PUCCH format 0. In this way, the user equipment can obtain frequency diversity gain. In more detail, the user equipment can obtain frequency diversity gain according to M bit Bit UCI(M bit =1 or 2) to determine the cyclic shift (CS) value m cs In addition, by determining the CS value m cs A sequence obtained by cyclically shifting a base sequence having a length of 12 can be mapped to 12 REs of one OFDM symbol and one RB for transmission. bit =1, the 1-bit UCI 0 and 1 can be mapped to two cyclic shift sequences with a cyclic shift value difference of 6. In addition, when M bit=2, the 2-bit UCI 00, 01, 11 and 10 can be mapped to four cyclic shift sequences with cyclic shift values ​​differing by 3 respectively.

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

[0115] PUCCH format 2 can deliver more than 2 bits of UCI. PUCCH format 2 can be sent through one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. When PUCCH format 2 is sent in two OFDM symbols, the sequences sent in different RBs of the two OFDM symbols can be the same as each other. Here, the sequence can be a plurality of modulated complex-valued symbols d(0), ..., d(M symbol-1 ). Here, M symbol It can be M bit / 2. Through this, the UE can obtain frequency diversity gain. More specifically, for M bit bits UCI (M bit >2) Bit-level scrambling, QPSK modulation, and mapping to RBs of one or two OFDM symbols. Here, the number of RBs can be one from 1 to 16.

[0116] PUCCH format 3 or PUCCH format 4 can deliver more than 2 bits of UCI. PUCCH format 3 or PUCCH format 4 can be transmitted through continuous OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 can be one of 4 to 14. Specifically, the UE uses e / 2-binary phase shift keying (BPSK) or QPSK for Mbit bits UCI (M bit >2) is modulated to generate complex-valued symbols d(0) to d(M symb-1 ). Here, when π / 2-BPSK is used, M symb =M bit , and when using QPSK, M symb =M bit / 2. The UE may not apply block-based extension to PUCCH format 3. However, the UE may apply block-based extension to one RB (i.e., 12 subcarriers) using a PreDFT-OCC length of 12, allowing PUCCH format 4 to have two or four multiplexing capabilities. The UE performs transmit precoding (or DFT precoding) on ​​the extended signal and maps it to each RE to transmit the extended signal.

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

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

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

[0120] Meanwhile, in 3GPP NR systems, user equipment can perform transmission / reception using a bandwidth that is less 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 portion of contiguous bandwidth within the carrier bandwidth. User equipment operating in TDD or unpaired spectrum can receive configurations of up to four DL / UL BWP pairs in one carrier (or cell). Furthermore, the user equipment can activate one DL / UL BWP pair. User equipment operating in FDD or 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). For each carrier (or cell), the user equipment can activate one DL BWP and one UL BWP. The user equipment may not receive or transmit in time-frequency resources other than the activated BWP. The activated BWP may be referred to as an active BWP.

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

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

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

[0124] refer to Figure 8As an example of a 3GPP NR system, the entire system band may include up to 16 component carriers, and each component carrier may have a bandwidth of up to 400 MHz. A component carrier may include one or more physically contiguous subcarriers. Figure 8 , each component carrier is shown to have the same bandwidth, but this is merely an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other on the frequency axis, the drawings are shown in a logical concept, and each component carrier may be physically adjacent to each other, or may be spaced apart.

[0125] A different center frequency can be used for each component carrier. Alternatively, a common center frequency can be used in physically adjacent component carriers. Figure 8 In the embodiment of FIG5 , all component carriers are physically adjacent, then center frequency A can be used in all component carriers. Alternatively, assuming that the respective component carriers are not physically adjacent to each other, center frequency A and center frequency B can be used in each component carrier.

[0126] When the total system frequency band is extended by carrier aggregation, the frequency band used to communicate with each UE can be defined in units of component carriers. UE A can use 100 MHz as the total system frequency band and use all five component carriers to perform communication. UEs B1 to B5 can use only 20 MHz bandwidth and use one component carrier to perform communication. UEs C1 and C2 can each use 40 MHz bandwidth and use two component carriers to perform communication. These two component carriers can be logically / physically adjacent or non-adjacent. UE C1 represents the case of using two non-adjacent component carriers, while UE C2 represents the case of using two adjacent component carriers.

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

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

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

[0130] At the same time, 3GPP NR uses the concept of cells to manage radio resources. A cell is defined as a combination of DL resources and UL resources, that is, a combination of DL CCs and UL CCs. A cell can be configured with DL resources alone or a combination of DL resources and UL resources. When carrier aggregation is supported, the link between the carrier frequency of the DL resources (or DL ​​CC) and the carrier frequency of the UL resources (or UL CC) can be indicated by system information. The carrier frequency refers to the center frequency of each cell or CC. The cell corresponding to the PCC is called the PCell, while the cell corresponding to the SCC is called the SCell. The carrier corresponding to the PCell in the DL is the DL PCC, while the carrier corresponding to the PCell in the UL is the UL PCC. Similarly, the carrier corresponding to the SCell in the DL is the DL SCC, while the carrier corresponding to the SCell in the UL is the UL SCC. Depending on the UE capabilities, a serving cell can be configured with one PCell and zero or more SCells. In the case of a UE in the RRC_CONNECTED state but not configured for carrier aggregation or not supporting carrier aggregation, there is only one serving cell configured with only the PCell.

[0131] As described above, the term "cell" used in carrier aggregation is distinguished from the term "cell" which refers to a geographical area where communication services are provided by a base station or an antenna group. That is, a component carrier may also be referred to as a scheduling cell, a scheduled cell, a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, to distinguish between cells representing a geographical area and cells in carrier aggregation, in this disclosure, cells in carrier aggregation are referred to as CCs, and cells in a geographical area are referred to as cells.

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

[0133] exist Figure 10 In the embodiment of the present invention, it is assumed that three DL CCs are merged. Here, it is assumed that DL component carrier #0 is DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are DL SCC (or SCell). In addition, it is assumed that DL PCC is set as the PDCCH monitoring CC. When cross-carrier scheduling is not configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is disabled, and each DL CC is able to send only the PDCCH for scheduling its PDSCH without CIF according to the NR PDCCH rule (non-cross-carrier scheduling, self-carrier scheduling). At the same time, if cross-carrier scheduling is configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is enabled, and a specific CC (e.g., DL PCC) can use CIF to send not only the PDCCH for scheduling the PDSCH of DL CC A but also the PDCCH for scheduling the PDSCH of another CC (cross-carrier scheduling). On the other hand, PDCCH is not sent in another DL CC. Therefore, the UE monitors the PDCCH not including the CIF to receive the self-carrier scheduled PDSCH according to whether cross-carrier scheduling is configured for the UE, or monitors the PDCCH including the CIF to receive the cross-carrier scheduled PDSCH.

[0134] on the other hand, Figure 9 and Figure 10 The subframe structure of the 3GPP LTE-A system is shown in the figure, and the same or similar configuration can be applied to the 3GPP NR system. However, in the 3GPP NR system, Figure 9 and Figure 10 The subframes can be replaced by time slots.

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

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

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

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

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

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

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

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

[0143] Next, the user interface 140 includes various input / output means provided in the UE 100. In other words, the user interface 140 can use various input means to receive user input, and the processor 110 can control the UE 100 based on the received user input. In addition, the user interface 140 can use various output means to perform output based on instructions from the processor 110.

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

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

[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 overall operation of each unit in the base station 200 and control the transmission and reception of data between the units. Here, the processor 210 can be configured to perform operations according to the embodiments described in the present disclosure. For example, the processor 210 can signal a time slot configuration and perform communication according to the signaled time slot configuration.

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

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

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

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

[0151] Figure 11 1 is a block diagram illustrating a UE 100 and a base station 200 according to an embodiment of the present disclosure, and the blocks shown separately are logically divided elements of the device. Therefore, the aforementioned elements of the device can be installed in a single chip or multiple chips according to the design of the device. In addition, part of the configuration of the UE 100, such as the user interface 140 and the display unit 150, can be selectively provided in the UE 100. In addition, the user interface 140 and the display unit 150 can be additionally provided in the base station 200 as necessary.

[0152] In the NR wireless communication system, the user equipment may send a codebook including hybrid automatic repeat request (HARQ)-ACK information to signal whether the reception of the downlink signal or channel is successful. The HARQ-ACK codebook includes one or more bits indicating whether the reception of the downlink signal or channel is successful. Here, the downlink channel may 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 may 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). The base station may set one of the two HARQ-ACK codebooks for the user equipment. The user equipment may use the HARQ-ACK codebook set for the user equipment.

[0153] When using a semi-static HARQ-ACK codebook, the base station can use RRC signaling to configure the number of bits in the HARQ-ACK codebook and the information used by each bit of the HARQ-ACK codebook to determine which downlink signal or channel was successfully received. Therefore, the base station does not need to signal the user equipment with the information required to send the HARQ-ACK codebook every time the HARQ-ACK codebook needs to be sent.

[0154] When a dynamic HARQ-ACK codebook is used, the base station can signal the information required to generate the HARQ-ACK codebook through the PDCCH (or DCI). In detail, the base station can signal the information required to generate the HARQ-ACK codebook through the downlink assignment index (DAI) field of the PDCCH (or DCI). In a specific embodiment, the DAI represents 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. 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 counter-DAI and total-DAI. Total-DAI indicates the number of downlink signals or channels for which the reception success or failure is indicated by the HARQ-ACK codebook until the current monitoring opportunity (MO). The counter-DAI indicates a HARQ-ACK codebook bit, which indicates the success or failure of reception of a downlink signal or channel among the downlink signals or channels of the current cell up to the current monitoring opportunity, which are indicated by the HARQ-ACK codebook. The PDCCH (or DCI) for scheduling the PDSCH may include the value of the counter-DAI corresponding to the scheduled PDSCH. Moreover, the PDCCH (or DCI) for scheduling the PDSCH may include the value of the total-DAI corresponding to the scheduled PDSCH. The user equipment may 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 may 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 present disclosure are applicable.

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

[0157] For example, the RRC configuration information may include information related to a control resource set (CORSET) and a search space so that the UE can detect a PDCCH including downlink control information. In this case, the information related to the control resource set may include 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 at least one of a control resource set length (duration) or frequency resource information. In this case, the information related to the search space may include 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 may receive DCI by detecting the PDCCH in the monitoring occasion based on the RRC configuration information (S12020). The UE may acquire 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 may be configured with different bits depending on the DCI format. For example, in DCI format 1_0, the DAI may be configured with 2 bits, and in DCI format 1_1, the DAI may be configured with 1 bit for the semi-static HARQ-ACK codebook and 2 bits for the dynamic HARQ-ACK codebook.

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

[0161] [Table 3]

[0162]

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

[0164] The UE may then receive the PDSCH or transmit the PUSCH to the base station using the allocated resources (S12030). If the UE receives the PDSCH from the base station, the UE may generate an HARQ-ACK codebook indicating ACK / NACK for 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 it in uplink control information (UCI) (S12040).

[0165] Figure 13An example of a method for counting the number of PDSCHs transmitted from a base station by a user equipment based on a pseudo code, which is applicable to an embodiment of the present disclosure, is shown.

[0166] Figure 13 (a) and (b) 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 through a specific DCI, and a stored total-DAI value.

[0167] Specifically, refer to Figure 13 (a), the UE may set the counter-DAI value of the PDCCH (or DCI) received in the serving cell c at monitoring opportunity m to Set the stored counter-DAI value to V temp , and set the stored total-DAI value (total-DAI) to V temp2 In this case, the range T of the value of the number of bits that can be expressed as DAI can be calculated by the following equation 1: D .

[0168] [Equation 1]

[0169]

[0170] Here, the monitoring opportunity index m and the cell index c are omitted. Tables 4 and 5 show the range of the value of the counter-DAI or total-DAI according to the number of bits of the counter-DAI or the total-DAI. Table 4 shows an example when the number of bits of the counter-DAI or the total-DAI is 2 bits, and Table 5 shows an example when the number of bits of the counter-DAI or the total-DAI is 1 bit.

[0171] [Table 4]

[0172]

[0173] [Table 5]

[0174]

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

[0176] [Table 6]

[0177]

[0178]

[0179] In this case, using the pseudo code in 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 ACK to determine the value of .

[0183] A new DCI format for providing ultra-reliable and low-latency communication (URLLC) services can be introduced. This new DCI format has a feature that can set the length of each DCI field to reduce the bit size. Hereinafter, the newly introduced DCI formats will be referred to as DCI format 0_2 and DCI format 1_2.

[0184] DCI format 0_2 is a DCI format for scheduling PUSCH, and DCI format 1_2 is a DCI format for scheduling 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 the PDSCH for eMBB service, and one HARQ-ACK codebook can be generated by collecting HARQ-ACK information about the PDSCH for URLLC service. In DCI formats 1_0, 1_1, and 1_2 for scheduling PDSCH, it is necessary to indicate in which HARQ-ACK codebook the HARQ-ACK information about the 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 with high priority (such as URLLC service), and index 0 can indicate HARQ-ACK for a PDSCH with low priority (such as eMBB service).

[0187] Alternatively, the HARQ-ACK of PDSCH for URLLC and the HARQ-ACK of 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 the different RNTIs of the PDCCH (or DCI) for scheduling the PDSCH of URLLC and the PDCCH (or DCI) for scheduling the PDSCH of eMBB, the UE can generate the HARQ-ACK codebook by distinguishing the HARQ-ACK of the PDSCH for URLLC and the HARQ-ACK of the PDSCH for eMBB.

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

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

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

[0192] Figure 14 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 is illustrated.

[0193] The DAI received from the PDCCH (or 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 DCI format 1_0, the number of bits of the counter-DAI is fixed to 2 bits, and in 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 DCI format 1_2 and 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 used to generate the HARQ-ACK codebook in DCI format 1_2. In 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] Reference Figure 14 , the PDSCH corresponding to one HARQ-ACK codebook for one UE can be scheduled according to DCI format 1_0, DCI format 1_1, or DCI format 1_2. That is, the DCI formats of the PDSCH corresponding to one HARQ-ACK codebook can have different lengths of counter-DAI bit sizes. Hereinafter, a method for generating an HARQ-ACK codebook will be described when the DCI formats have different lengths of counter-DAI bit sizes.

[0196] Figure 15 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 is illustrated.

[0197] Reference Figure 15 , the UE may generate a HARQ-ACK codebook for a PDSCH scheduled by each PDCCH having a different DCI format and send it 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 may also change. In this case, the UE can generate a HARQ-ACK codebook including HARQ-ACK bits for the PDSCH scheduled by the PDCCH (or DCI) with a different number of DAI fields and send it to the base station.

[0199] In this case, since the number of bits of the DAI field is different, it is difficult for the UE to count 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", it is difficult for the UE to determine whether the two received PDSCHs are sent consecutively.

[0200] Therefore, when the number of bits of the counter-DAI of each received PDCCH (or DCI) is different, the UE can identify 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 identifying only some of the bits of the counter-DAI with a larger number of bits as valid bits, and can match the number of bits by expanding and interpreting the bits of the counter-DAI with 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 different, only some bits of the counter-DAI with a larger number of bits are identified as valid bits to generate the HARQ-ACK codebook. In this case, the number of valid bits is equal to the number of bits of the DAI field with a smaller number of bits in the DAI field of the received PDCCH (or DCI). In addition, in DCI format 1_0 and DCI format 1_1, the number of bits of the counter-DAI can be fixed to 2 bits, and in 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 with a smaller number of bits in the DAI field has the same number of bits as the number of bits of the counter DAI included in DCI format 1_2. That is, when the UE is configured to monitor DCI format 1_2, the UE can recognize that the number of bits of the counter-DAI of DCI format 1_2 is a valid number of bits, and can recognize that among the 2-bit counter-DAI of DCI format 1_0 or DCI format 1_1, only the valid number of bits is the valid bits of the counter-DAI.

[0203] Specifically, when the bit size of the counter-DAI of DCI format 1_2 is set to N C-DAI When N is set to 0, only N bits are set to N among the two bits of the Counter-DAI field of DCI format 1_0 and DCI format 1_1, which are other formats of DCI. C-DAI bits may be determined to be valid. In this case, the bit determined to be valid may be the LSB N C-DAI bits or MSBN CDAI bits.

[0204] In addition, the counter-DAI value can be calculated based on N C-DAI 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 11, the UE may set the valid bit of the counter-DAI to 1 bit. 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 DCI format 1_2 is 1 bit, the UE may 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 2-bit counter-DAI value C2 can be converted to the same bit value as the 1-bit counter-DAI value C1 by C1=(C2-1)mod2+1. This method has the same effect as determining that 1 bit of the LSB is significant 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 transmitted consecutively 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 may not be able to recognize it. C-DAI When set to 1 bit, reception failure of at most one PDCCH can be detected, but reception failure of two or more consecutive PDCCHs cannot be detected.

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

[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 effective number of bits of Counter-DAI is only 1 bit, it is impossible to recognize that two or more consecutive PDCCHs are not detected. Therefore, it may not be easy to detect a reception failure of a 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 may be determined by extending and interpreting the number of bits of the counter-DAI based on a greater number of 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 with the smallest number of undetected PDCCHs among the candidate values ​​2 or 4 that may be the value of the counter-DAI. In other words, when it is determined that the counter-DAI of the subsequently received PDCCH (or DCI) is 2, it is determined that the reception of two PDCCHs (or DCIs) with counter-DAI values ​​4 and 1 has failed. However, when it is determined that the counter-DAI of the received PDCCH (or DCI) is 4, the UE determines that there is no PDCCH (or DCI) that has failed to be received. When the probability that the UE fails to receive the PDCCH is p, it is determined that the counter-DAI is 2 and the probability of reception failure of two consecutive PDCCHs (or DCIs) is p 2 , and the probability that the counter-DAI is 4 and there is no PDCCH (or DCI) reception failure is determined to be 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, a counter-DAI of 4 with a probability of 1-p is better than a counter-DAI of 4 with a probability of p. 2 The counter-DAI 2 occurs more frequently. Therefore, in the above case, the value of the counter-DAI is more likely to be 4 than 2, and it is desirable to determine the counter-DAI to be 4.

[0229] Table 7 below shows an example of the value of the counter-DAI when the counter-DAI bit is expanded and interpreted for the counter-DAI of the previously received DCI. 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 represent each bit value.

[0233] For another example of Proposal 2, DCI format 1_0 and DCI format 1_1 include a two-bit counter-DAI, and thus, when the bit of the counter-DAI is binary "00", the counter-DAI value may be 1, and when the bit is binary "01", the counter-DAI value may be 2. Furthermore, when the bit of the counter-DAI is binary 10, the counter-DAI value may be 3, and when the bit of the counter-DAI is binary 11, the counter-DAI value may be 4.

[0234] In this case, when N is the bit size of the counter-DAI of DCI format 1_2 C-DAI When the value of is 0 bits, the UE may extend the number of bits of the counter-DAI of 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 0-bit counter-DAI 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 four candidate values, the UE may determine the counter-DAI value as a value continuous with the counter-DAI value of the previously received DCI.

[0236] Table 8 below shows an example of a counter-DAI value extended and interpreted for a counter-DAI of a 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 DCI format 1_2 is less than 2 bits, there may be multiple possible 2-bit counter-DAI values. The UE may select a value from the multiple possible 2-bit counter-DAI values.

[0240] In order to select one of the multiple candidate values, the following specific method may be used.

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

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

[0243] [Equation 2]

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

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

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

[0247] For example, when V temp When the value of is 1 and the currently received counter-DAI of DCI format 1_2 is 0 in binary, the counter-DAI may have a value of 1 or 3. When it is determined that the counter-DAI value is 3, it indicates a case where one PDCCH (counter-DAI value is 2) has been sent between the previously received PDCCH (counter-DAI value is 1) and the currently received PDCCH (counter-DAI value is 3) but its reception has failed. When it is determined that the counter-DAI value is 1, it indicates a case where three PDCCHs (counter-DAI values ​​are 2, 3, and 4) have been sent between the previously received PDCCH (counter-DAI value is 1) and the currently received PDCCH (counter-DAI value is 1) but their reception has failed. According to the previous embodiment, it is assumed that the minimum number of PDCCHs has been sent but their reception has failed, 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 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, N T-DAI In this case, similar to the method of Proposal 1, only the LSB (or MSB) N of the two-bit total-DAI field of DCI format 1_1 including the 2-bit total-DAI field is used. T-DAI bits are determined as valid bits, and can be based on the valid N T-DAI bits to determine the total DAI value.

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

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

[0251] In another embodiment of the present disclosure, when DCI format 1_1 is not received and DCI format 1_2 is received at one monitoring occasion, the value of the 2-bit Total-DAI may be determined as follows.

[0252] When N T-DAI When the value of (which is the bit size of the total-DAI in DCI format 1_2) is 1 bit, it can be expanded and interpreted as a 2-bit total-DAI value. For example, when the bit of the 1-bit total-DAI 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 N T-DAI When the value of (which is the bit size of the total-DAI in DCI format 1_2) is 0 bits (i.e., when the total-DAI is not included in the DCI format), the 0-bit total-DAI can be interpreted as a 2-bit total-DAI value.

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

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

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

[0257] [Equation 3]

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

[0259] If Z is one of the values ​​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 whose reception has failed among the PDCCHs that have been transmitted since the last PDCCH of the current monitoring opportunity.

[0260] Table 9 below is a table showing an example of a 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 opportunity. For example, when the previous V temp2 When the value of is 2 and the currently received counter-DAI of DCI format 1_2 is binary number 0, the total-DAI can have 1 or 3.

[0264] When the total-DAI value is determined to be 3, it indicates that one PDCCH (counter-DAI value is 3) has been transmitted since the last received PDCCH (counter-DAI value is 2), but the UE has not detected it. When the total-DAI value is determined to be 1, it indicates that three PDCCHs (counter-DAI values ​​are 3, 4, and 1) have been transmitted since the last received PDCCH (counter-DAI value is 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 total-DAI value of the received PDCCH is 3.

[0265] Through the above method, even when the number of bits of the counter-DAI or total-DAI of DCI with different formats is different, the UE can determine the effective number of bits or expand and interpret the number of bits, and multiplex the HARQ-ACK codebook of the PDSCH scheduled by multiple DCIs and send it to the base station.

[0266] Figure 16 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 is illustrated.

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

[0268] Specifically, if Figure 16 As shown, the UE can multiplex (or piggyback) the HARQ-ACK bits of the received PDSCH with the PUSCH and send them to the base station. In this case, the DCI format used to schedule the PDSCH is DCI format 1_0, DCI format 1_1, and / or DCI format 1_2. In addition, the DCI format used to schedule 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 may be set to 0, 1, or 2 bits. In addition, the length of the Counter-DAI field included in the DCI format 1_2 may be set to 0, 1, or 2 bits.

[0270] Furthermore, DCI format 0_0 and DCI format 0_1 ​​may include a 2-bit UL DAI field, and DCI format 1_0 and DCI format 1_1 may 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 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, that is, the DCI format may 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 (for example, when the length of the UL DAI field is 2 bits and the length of the Counter-DAI field is 1 bit), the UE may 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 may be bits closest to the MSB or LSB of the UL DAI field.

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

[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, 3 when the 2 bits are 10, and 4 when the 2 bits are 11.

[0275] The UE may determine the number of HARQ-ACK bits of the PDSCH that is not received using a UL DAI value obtained by using the bits of the UL DAI field determined to be valid and a 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 has not been received. However, when Y<X, it can be determined that XY PDSCHs have not been received, and when X<Y, it can be determined that T-(YX) PDSCHs have not been received. Here, T=2 N , and N is the number of bits of the Counter-DAI field.

[0277] In a 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 (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 first determine the UL DAI value based on the length of the UL DAI field, and then modify the determined UL DAI value based on the counter-DAI field to determine the final UL DAI value.

[0278] The process of determining the value of UL DAI according to the length of the 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 determining the UL DAI value according to the UL DAI field, the UE can modify the determined UL DAI value as follows to match the Counter-DAI field, so as 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 value of UL DAI is Z, the following Equation 4 can be used to calculate the final UL DAI value (X).

[0282] [Equation 4]

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

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

[0285] In the 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, while the length of the Counter-DAI field is 1 bit), the UE can assume (or identify) that the range of UL DAI values is the same as the range of values that the Counter-DAI can indicate. For example, when the values that the Counter-DAI can indicate are 1, 2, 3, or 4, the value of UL DAI can be identified as one of 1, 2, 3, and 4.

[0286] Specifically, the UE can determine the UL DAI value based on 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". In addition, when the bit value of 2 bits 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 must always 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 UL DAI values ​​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 UL DAI can have values ​​of 1 and 2.

[0288] That is, the UE does not expect to be indicated with a UL DAI value indicating a value outside the range of possible values ​​of Counter-DAI. It is not expected to indicate 10 or 11 where the value of UL DAI indicates 3 or 4. That is, when this value is indicated, the UE may determine an error condition.

[0289] As described above, in 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, the UL DAI value of 2 bits can be determined in the same manner as the method for determining the 2-bit total-DAI value.

[0290] That is, the value of UL DAI may be determined by using the last received 2-bit Counter-DAI value. Table 10 below is a table showing an example of a 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 When the value of is 2 and the bit value of the received UL-DAI of DCI format 0_2 is 0, the UL-DAI value can have 1 or 3.

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

[0295] Figure 17 An example of a downlink assignment indicator for each piece of downlink control information detected in a monitoring opportunity according to an embodiment of the present disclosure is illustrated.

[0296] In another embodiment of the present 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 the bit size of the Counter-DAI field of DCI format 1_0, 1_1 or DCI format 1_2, the UE may 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 When the counter-DAI value is 1, 2, ..., 2^N C-DAI Here, when the maximum value C D is 2^N C-DAI When, that is, when the bit size N of the Counter-DAI field C-DAI When the bit value of the Counter-DAI field is 2 bits, the Counter-DAI value may 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, C D The value of can be 4.

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

[0299] If the UE receives a DCI format for scheduling a PDSCH in 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 until the current serving cell c of the current monitoring occasion m of the DCI format has been received, it has received C for scheduling PDSCH 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 of the current serving cell c up to the current monitoring occasion m in which the DCI format has been received is X, the counter-DAI value of the DCI format is V C-DAI,c,m =(X-1mod C D )+1.

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

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

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

[0304] For example, when U D The value of is 4 and C D When the value of 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 (a) illustrates an example of a counter-DAI value of a DCI format received in monitoring opportunities (MO) #0 to #6.

[0305] According to the definition of the counter-DAI value, the counter-DAI value of the DCI format received at MO#0 is 1, the counter-DAI value of the DCI format received at MO#1 is 2, the counter-DAI value of the DCI format received at MO#2 is 1, the counter-DAI value of the DCI format received at MO#3 is 2, the counter-DAI value of the DCI format received at MO#4 is 1, the counter-DAI value of the DCI format received at MO#5 is 2, and the counter-DAI value of the DCI format received at MO#6 is 1. Furthermore, the UE receives a DCI format for scheduling the PUSCH. The UL DAI value of the received DCI format is 3. This is because seven DCI formats for scheduling the PDSCH have already been received.

[0306] In the present disclosure, when the bit size of Counter-DAI and the bit size of UL DAI are different from each other, a method for generating a HARQ-ACK codebook by a UE is proposed. Figure 17 In (b), the DCI formats of MO#4 and MO#5 are not received. Since the UE has already received a DCI format with a counter-DAI value of 2 on MO#3 and a DCI format with a counter-DAI value of 1 on MO#6, the UE may not be aware of the reception failure of the DCI formats on MO#4 and MO#5. Therefore, the UE only generates 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 the PUSCH, the UE can recognize 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.

[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 present disclosure is illustrated.

[0309] Reference Figure 19 , a pseudo code may be used to generate a HARQ-ACK codebook by using the UL-DAI value and the counter-DAI value, and the HARQ-ACK codebook may be sent to the base station. Figure 19 An example of multiplexing 2-bit UL-DAI and 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 them, similar to UL DAI. UE can compare V' temp and V temp2 To determine the value of j. If V temp2 <V' temp , the value of j can be determined by the following equation 7.

[0319] [Equation 7]

[0320]

[0321] Otherwise, j can remain as is. Using the value of j, the UE can determine the size of the HARQ-ACK codebook O ACK If the UE is configured to receive only 1TB per PDSCH, it can be calculated by the following equation 8: ACK .

[0322] [Equation 8]

[0323]

[0324] If the UE is configured to receive 2TB for each PDSCH, it can be calculated by the following equation 9: ACK .

[0325] [Equation 9]

[0326]

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

[0328] [Table 11]

[0329]

[0330]

[0331]

[0332] Figure 18 FIG. 2 illustrates another example of a downlink assignment indicator for each piece of downlink control information detected in a monitoring opportunity according to an embodiment of the present disclosure.

[0333] In another embodiment of the present 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 the bit size of the counter-DAI field of DCI format 1_0, 1_1 or DCI format 1_2, the UE may generate a HARQ-ACK codebook through 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 When the counter-DAI value is 1, 2, ..., 2^N C-DAI Here, when the maximum value C D is 2^N C-DAI When, that is, when the bit size N of the Counter-DAI field C-DAI When the bit value of the Counter-DAI field is 2 bits, the Counter-DAI value may 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, C D The value of can be 4.

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

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

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

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

[0339] If the UE receives a DCI format for scheduling PDSCH at monitoring time m, and the total-DAI value of the DCI format is VT-DAI,m , the UE can determine that it has received T for scheduling PDSCH until the current monitoring occasion m of the DCI format is received D *i+V T-DAI,m DCI formats. Here, i is a non-negative integer.

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

[0341] As an example, observe T D The value of C is 4 and D The value of is 2. A value of 1 or 2 may be set as the Counter-DAI value of the UE, and the Total-DAI may have a value of 1, 2, 3, or 4.

[0342] Figure 18 (a) illustrates (Counter-DAI, Total-DAI) values ​​of the DCI format received on MO#0 to #6. According to the definition of counter-DAI value and 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 present 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. Figure 18 As shown in (b), the UE may not receive the DCI formats of MO#4 and MO#5. In this case, the UE has received a DCI format with a counter DAI value of 2 on MO#3 and a DCI format with a counter DAI value of 1 on MO#6. Therefore, the UE may not be able to recognize the failure to receive 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 the following equation 11.

[0353] [Equation 11]

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

[0355] In Equation 11, V' temp With 1, 2, ..., T D One of them, similar to total-DAI. UE can compare V' temp and V temp2 To determine the value of j. If V temp2 <V' temp , the value of j can be calculated by the following equation 12.

[0356] [Equation 12]

[0357]

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

[0359] [Equation 13]

[0360]

[0361] If the UE is configured to receive 2TB for each PDSCH, then the following equation 14 can be used to calculate O ACK .

[0362] [Equation 14]

[0363]

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

[0365] The bit size of the Counter-DAI field of DCI format 1_0, 1_1 or 1_2 received in serving cell c at monitoring occasion m may be N C-DAI,c,m 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 It can be 2^N C-DAI,c,m That is, when the bit size N of the Counter-DAI field C-DAI,c,m When the bit value of the Counter-DAI field is 2 bits, the Counter-DAI value is 1 when it is "00", 2 when it is "01", 3 when it is "10", and 4 when it is "11". D The value of is 4, when N C-DAI,c,m When the bit value of the Counter-DAI field is 0, the Counter-DAI value is 1, and when it is 1, it is 2. In addition, C D,c,m The value of is 2.

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

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

[0368] In the present disclosure, when the bit sizes of Counter-DAI are different from each other, a method for generating a HARQ-ACK codebook by a UE is proposed. In an embodiment of the present 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 field of the DCI format, and C D,min The value can 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, N C-DAI,min The value of is 1, and C D,min The value of is 2.

[0370] When the value of Counter-DAI received in serving cell c at monitoring opportunity m is V C-DAI,c,m When the value of the counter-DAI can have 1, 2, ..., C as described aboveD,c,m First, the UE can use V based on the following equation 15 C-DAI,c,m To determine the number S of DCI formats used to schedule PDSCH c,m .

[0371] [Equation 15]

[0372]

[0373] In Equation 15, floor(j*C D,min / C D,c,m )*C D,c,m The part is used to indicate the number of DCI formats used to schedule PDSCH. c,m Satisfaction (S c,m -1mod C D,c,m )+1=V C-DAI,c,m part.

[0374] That is, the value of j can be adjusted by scaling and / or rounding down so that S c,m –V C-DAI,c,m The value of C in Equation 15 is D,c,m multiples of .

[0375] The UE will obtain the number of DCI formats S based on the counter DAI value received in the serving cell c at the current monitoring occasion m. c,m The number of DCI formats just obtained W temp Compare. If S c,m ≤W temp , then the value of j can be increased until S c,m >W temp In this case, the value of j can be increased by one. If S c,m >W temp , then j can remain as it is.

[0376] j is the number of C D,min Parameters of the DCI format.

[0377] When this is expressed in pseudocode, 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 PUSCH, T D =U D , after the while statement V temp2 Can be set to the value of UL DAI.

[0383] DCI format 1_2 may not include Counter-DAI (this includes being configured with 0 bits). In this case, the UE may have ambiguity about the method used to determine the dynamic HARQ-ACK codebook. That is, when designing a dynamic HARQ-ACK codebook (Type 2 HARQ-ACK codebook), the base station may be configured to omit some of the DCI fields in order to increase the UE's probability of successful PDCCH reception. That is, the base station may omit some of the DCI fields or set the field size to 0 bits.

[0384] For example, the base station may omit the Counter-DAI field from the DCI field 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 be used not only to determine the position of the HARQ-ACK bit in the HARQ-ACK codebook, but also to determine the size of the HARQ-ACK codebook.

[0386] In order for the UE to use the HARQ-ACK codebook to send HARQ-ACK bits for notifying the base station of ACK / NACK (or DTX) for multiple PDSCHs, the value of the counter-DAI field of the DCI needs to be arranged in ascending order. However, when the counter-DAI field is omitted, the value of the counter-DAI field may not be sorted in ascending order by the explicit value. Therefore, a method for determining the order of the HARQ-ACK bits 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 DCI are omitted will be described.

[0388] Figure 20 An example of a method for transmitting HARQ-ACK of a PDSCH according to a reception order of a PDCCH according to an embodiment of the present disclosure is illustrated.

[0389] Reference Figure 20 , when some fields of the DAI field are omitted or the size is set to 0 bits, the UE may generate the HARQ-ACK codebook according to the order of receiving the PDCCH for scheduling the PDSCH instead of the counter-DAI value.

[0390] In the first embodiment of the present disclosure, the UE may determine the order of HARQ-ACK bits for the PDSCH in the HARQ-ACK codebook based on the time information of the PDCCH received for scheduling the PDSCH. That is, the UE may determine the order of the HARQ-ACK bits included in the HARQ-ACK codebook according to the order in which the PDCCH is received, regardless of the value of the counter-DAI in the PDCCH transmitted for scheduling the PDSCH.

[0391] For example, when Figure 20 As shown in (a), when the starting symbol of the CORESET including the PDCCH for scheduling the first PDSCH or its search space is located before the starting symbol of the CORESET including the PDCCH for scheduling the second PDSCH or its search space, in the HARQ-ACK codebook, as shown in Figure 20 As shown in (b), B(1) as the HARQ-ACK bit of the first PDSCH can be arranged at a position before B(0) as the HARQ-ACK bit of the second PDSCH. If the starting symbol of the CORESET or the search space is the same as each other, the HARQ-ACK bit of the PDSCH scheduled by the PDCCH preceding the last symbol of the CORESET or its search space can be arranged at a preceding position.

[0392] Figure 21 An example of a method for transmitting HARQ-ACK for a PDSCH according to time information on the PDSCH according to an embodiment of the present disclosure is illustrated.

[0393] Reference Figure 21 , when some of the DAI fields are omitted or the size is set to 0 bits, the UE may generate a HARQ-ACK codebook based on time information related to the PDSCH included in the PDCCH for scheduling the PDSCH instead of the counter-DAI value.

[0394] In the second embodiment of the present disclosure, the UE may determine the order of the HARQ-ACK bits of the PDSCH constituting the HARQ-ACK codebook based on the time information about the PDSCH. Specifically, when the start symbol of the first PDSCH is positioned before the start symbol of the second PDSCH, the position of the HARQ-ACK bit of the first PDSCH in the HARQ-ACK codebook may be before the position of the HARQ-ACK bit of the second PDSCH.

[0395] For example, Figure 21As shown in (a), based on the time information included in the PDCCH for scheduling the first PDSCH and the time information included in the PDCCH for scheduling the second PDSCH, the start symbol of the second PDSCH can be positioned before the start symbol of the first PDSCH. In this case, as Figure 21 As shown in (b), in the case where the UE sends HARQ-ACK for the first PDSCH and HARQ-ACK for the second PDSCH through PUCCH, B(1) which is the HARQ-ACK bit of the second PDSCH can be positioned before B(0) which is the HARQ-ACK bit of the first PDSCH.

[0396] Figure 22 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 present disclosure is illustrated.

[0397] Reference Figure 22 , when some of the DAI fields are omitted or the size is set to 0 bits, the UE may generate a HARQ-ACK codebook based on the HARQ process ID (or HARQ process number) included in the PDCCH for scheduling the PDSCH instead of the counter-DAI value.

[0398] In the third embodiment of the present disclosure, the UE may determine the order of the HARQ-ACK bits in the HARQ-ACK codebook according to the value of the HARQ process ID (or HARQ process number) of the PDCCH used to schedule the PDSCH.

[0399] Specifically, when the HARQ process ID of the first PDSCH in the PDCCH used to schedule the first PDSCH is A, and the HARQ process ID of the second PDSCH in the PDCCH used to schedule the second PDSCH is B, in the HARQ-ACK codebook, the HARQ-ACK bit of the PDSCH with a smaller value in the A and B values ​​can be arranged before the HARQ-ACK bit of the PDSCH with a larger value.

[0400] That is, the position of the HARQ-ACK bits can be determined according to the ascending order of the HARQ process ID. Here, the UE can assume that the HARQ process IDs of the HARQ-ACKs sent using one HARQ-ACK codebook have different values ​​from each other. Therefore, it is not desirable to generate one HARQ-ACK codebook with HARQ-ACK bits for 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 omitted, or the size 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 send it to the base station through UCI.

[0402] In this case, if Figure 22 As shown in (a), the value of the HARQ-ACK process ID or HARQ-ACK process number of the PDCCH used to schedule the second PDSCH may be "0", and the value of the HARQ-ACK process ID or HARQ-ACK process number of the PDCCH used to schedule the first PDSCH may be "1". In this case, as Figure 15 As shown in (b), based on the ascending order of HARQ-ACK process ID or HARQ-ACK process number, B(0) (which is the HARQ-ACK bit for the second PDSCH with 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).

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

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

[0406] In the sixth embodiment of the present disclosure, the UE can determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook by using the frequency domain information about the PDCCH used to schedule the PDSCH. Here, the frequency domain information can be the lowest PRB index among the PRBs to which the PDCCH is allocated. Here, the index represents a common PRB index, and the index indicates how far away from point A is in the frequency domain. Point A represents the reference frequency of the UE during the initial access process, and the specific location 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 the subcarrier spacing provided by the higher layer parameter subCarrierSpacingCommon and overlaps the SS / PBCH block used by the UE for initial cell selection. OffsetToPointA is expressed in resource blocks, assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2.

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

[0409] The UE may be configured to monitor multiple PDCCHs and may receive different PDCCHs in different frequency domains. In this case, the UE may arrange the HARQ-ACK bits of the PDSCHs received in different frequency domains in the HARQ-ACK codebook according to the ascending order of the lowest PRB index of the PDCCH used to schedule the PDSCH. In this method, when the UE receives multiple PDCCHs in one CORESET (or search space) in the fifth embodiment, the order of the HARQ-ACK bits in the HARQ-ACK codebook may 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 each PDSCH in the HARQ-ACK codebook. For example, the first embodiment and the third embodiment can be combined. With this combination, the order of the HARQ-ACK bits in the HARQ-ACK codebook can be first determined based on the time domain information about the PDCCH, and when the order is not determined by the time domain information, the order can be determined based on the HARQ process ID of the third embodiment. Alternatively, 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 based on the time domain information about the PDCCH. Then, when the order cannot be determined by the time domain information according to each embodiment, the order is determined based on the cell information, and when the order cannot be determined by the cell information, the order is determined based on the information about the CORESET (or search space). In addition, when the order cannot be determined using information about the CORESET (or search space), the order can be determined based on the frequency domain allocation information about the PDCCH.

[0411] In addition, in another embodiment of the present disclosure, when each PDSCH is scheduled by multiple PDCCHs and the number of bits of the counter-DAI field included in the multiple PDCCHs is different from each other, the UE can generate each HARQ-ACK codebook separately 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 may generate a HARQ-ACK codebook for the PDSCH scheduled by the PDCCH including the Counter-DAI with a bit number of 2 bits and / or a HARQ-ACK codebook for the PDSCH scheduled by the PDCCH including the Counter-DAI with a bit number of 1 bit, and transmit them to the base station.

[0413] That is, for a UE, one HARQ-ACK codebook may include only HARQ-ACK of a PDSCH scheduled using a DCI format having the same number of bits of Counter-DAI.

[0414] Through the first to sixth embodiments described above, the UE can determine the position of the HARQ-ACK bit 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, problems may arise 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 may differently determine the size of the HARQ-ACK codebook due to the non-reception of the PDCCH, and thus a method for solving this problem is needed.

[0416] In this case, the UE can always assume that the remainder when the size of the dynamic HARQ-ACK codebook is divided by X is Y. It is expected that X = 4 and Y = 1. That is, the size of the dynamic HARQ-ACK codebook can be determined as 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 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 may be included in the DCI of the PDCCH corresponding to the HARQ-ACK of one HARQ-ACK codebook, or may not be included therein. In this case, in the HARQ-ACK codebook, the UE determines the position of the HARQ-ACK of the PDSCH scheduled by the DCI including the Counter-DAI field and the HARQ-ACK of the PDSCH scheduled by the DCI without the Counter-DAI field.

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

[0419] Specifically, the UE generates a first sub-HARQ-ACK codebook by collecting only the HARQ-ACK of the PDSCH scheduled by the DCI including the counter-DAI field. In this case, the position of the HARQ-ACK in the first sub-HARQ-ACK codebook is determined by using the value of the counter-DAI field (i.e., the position is determined according to the ascending order of 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 and their combinations can be used.

[0420] In addition, the UE generates a second sub-HARQ-ACK codebook by collecting only the HARQ-ACK of the PDSCH scheduled by the DCI, in which the counter-DAI field is omitted or set to a 0-bit value. In this case, the position of the HARQ-ACK in the second sub-HARQ-ACK codebook can be determined according to the above-mentioned first to sixth embodiments and their combinations. The UE can continuously combine the first sub-HARQ-ACK codebook and the second sub-HARQ-ACK codebook (i.e., so 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 may increase accordingly.

[0421] In another embodiment of the present disclosure, in the above case, the UE may ignore the counter-DAI field included in the DCI. That is, by treating all DCI as DCI without the counter-DAI field, the position of the HARQ-ACK bit in the HARQ-ACK codebook can be determined by using the first to sixth embodiments and their combination.

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

[0423] Specifically, a UE configured with a semi-static HARQ-ACK codebook needs to send a HARQ-ACK codebook including a predetermined number of HARQ-ACK bits via the 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 as a higher layer may include at least the CBG configuration information of the cell, and the UE may receive the CBG configuration information for each cell. The CBG configuration information may be used to configure the maximum number of CBGs that a PDSCH (or TB) may include, and may be represented as N MAX In the semi-static HARQ-ACK codebook, when the HARQ-ACK bits of PDSCH are included, it is necessary to determine how many HARQ-ACK bits one PDSCH corresponds to. Generally, when CBG transmission is not configured, PDSCH can correspond to 1 bit of HARQ-ACK (2 bits when 2TB transmission is configured), and when CBG transmission is configured, PDSCH can correspond to N MAX bits of HARQ-ACK.

[0425] When semi-static HARQ-ACK is configured for the UE, 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 send only 1 bit of HARQ-ACK for PDSCH by including it in the PUCCH.

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

[0427] -When the UE needs to send HARQ-ACK for an SPS PDSCH

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

[0429] - When sending HARQ-ACK for a PDSCH scheduled in DCI format 1_0 or DCI format 1_2

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

[0431] On the contrary, when CBG-based transmission is configured, and when at least one of the following conditions is met, and two or more downlink cells (or carriers) are configured in the UE, or there are two or more monitoring opportunities for receiving PDCCH, the UE can release 1 bit of HARQ-ACK (TB level HARQ-ACK) of DCI or PDSCH by repeating SPS PDSCH or SPS PDSCH MAX times to generate N MAX bits.

[0432] -When sending HARQ-ACK for an SPS PDSCH

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

[0434] - When sending HARQ-ACK for a PDSCH scheduled in DCI format 1_0 or DCI format 1_2

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

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

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

[0438] Reference Figure 23 , the UE may generate a HARQ-ACK codebook including HARQ-ACK bits for multiple PDSCHs scheduled by DCI on multiple PDCCHs transmitted from the base station. In this case, when the format of the DCI is different and the number of bits of the DAI field included in each DCI is different, the UE may interpret the value of the DAI field under specific 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 may receive setting information including information for receiving the PDCCH before receiving the first PDCCH.

[0440] The first PDCCH may include a first counter downlink assignment indicator (DAI) indicating the number of scheduled PDSCHs until a time point at which the first PDCCH is monitored and a first total DAI indicating the number of all PDSCHs scheduled in the 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 a first PDSCH based on the first PDCCH ( S23030 ), and receives a second PDSCH based on the second PDCCH ( S23040 ).

[0443] After receiving the first PDSCH and the second PDSCH, the UE generates HARQ-ACK bits 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 the 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 using the methods of Proposals 1 to 3 above.

[0446] 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 bits of the second counter DAI whose number 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 may be interpreted by extending the number of bits of the second counter DAI to the same number of bits as that 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 may be interpreted as a value having a minimum 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 present disclosure.

[0450] Reference Figure 24 , the base station can schedule PDSCH to the UE through multiple PDCCHs with different formats. In this case, when the number of bits of the DAI field included in the DCI of different formats on the PDCCH is different, the base station can receive the HARQ-ACK codebook for the PDSCH scheduled by the DCI of 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 may transmit setting information including information for receiving the PDCCH before transmitting the first PDCCH.

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

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

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

[0455] The base station receives a HARQ-ACK codebook including HARQ-ACK bits for each of the first PDSCH and the second PDSCH generated by the UE through uplink control information (UCI) from the UE (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 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 using the methods of Proposals 1 to 3 above.

[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 bits of the second counter DAI whose number is 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 may be interpreted by extending the number of bits of the second counter DAI to the same number of bits as that 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 may be interpreted as a value having a minimum difference from a value indicated by the first counter DAI among the plurality of candidate values.

[0460] The above description of the present disclosure is for illustration, and it will be understood by those skilled in the art that the present disclosure can be easily modified into other specific forms without changing the technical spirit or essential features of the present disclosure. Therefore, it should be understood that the above embodiments are illustrative and not restrictive in all aspects. 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 indicated by the claims to be described below rather than the detailed description above, and it is to be interpreted 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: Communication module; as well as a processor, the processor being configured to control the communication module, Wherein, the processor is configured to: Receiving a plurality of first downlink control information (DCI) for downlink scheduling formats, wherein each first DCI format includes an Nc-bit counter downlink assignment index (c-DAI), and Nc is 1; receiving a second DCI format for scheduling a physical uplink shared channel (PUSCH), wherein the second DCI format includes a 2-bit uplink DAI (UL-DAI); determining a number of hybrid automatic repeat request (HARQ)-acknowledgement (ACK) bits for the downlink scheduling, the number of the HARQ-ACK bits being based on: Corresponding to the value of Floor(j*C / 4), where -j is a counter number for the case where the mth Nc-bit c-DAI has a value less than or equal to the (m-1)th Nc-bit c-DAI within the plurality of received Nc-bit c-DAIs, where m is a positive integer, C is 2^Nc, and floor is a round-down function; and Control information including the HARQ-ACK bit is transmitted via the PUSCH.

2. The user equipment according to claim 1, wherein The number of HARQ-ACK bits is based on a value O corresponding to 4*(floor(j*C / 4)+Q)+V, where -Q is 0 or 1, and -V is the value of the 2-bit UL-DAI and is in the range of 1 to 4.

3. The user equipment according to claim 2, wherein: The number of HARQ-ACK bits is determined to be one of 0 and 2*0.

4. The user equipment according to claim 2, wherein: Only when V is less than V temp When Q is 1, and Among them, V temp Determine a 2-bit c-DAI value converted from the value of the last one of the multiple received Nc-bit c-DAIs, so that the converted 2-bit c-DAI value corresponds to the number of downlink schedulings determined based on the multiple received Nc-bit c-DAIs.

5. The user equipment according to claim 4, wherein: The value of the last of the plurality of received Nc-bit c-DAIs and the converted 2-bit c-DAI value satisfies the relationship comprised in the following table: Wherein, X represents the value of the last one of the multiple received Nc-bit c-DAIs, and Y represents the converted 2-bit c-DAI value. The user equipment according to claim 1 , wherein: The Nc-bit c-DAI is associated with the bit position of the corresponding HARQ-ACK bit in the HARQ-ACK bits.

7. The user equipment according to claim 1, wherein: The Nc-bit c-DAI is related to the counter number of the corresponding downlink schedule, and the 2-bit UL DAI is related to the number of the downlink schedule.

8. The user equipment according to claim 1, wherein: The wireless communication system includes a wireless communication system based on the 3rd Generation Partnership Project (3GPP).

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 each first DCI format includes an Nc-bit counter downlink assignment index (c-DAI), and Nc is 1; receiving a second DCI format for scheduling a physical uplink shared channel (PUSCH), wherein the second DCI format includes a 2-bit uplink DAI (UL-DAI); determining a number of hybrid automatic repeat request (HARQ)-acknowledgement (ACK) bits for the downlink scheduling, the number of the HARQ-ACK bits being based on: Corresponding to the value of Floor(j*C / 4), where -j is a counter number for the case where the mth Nc-bit c-DAI has a value less than or equal to the (m-1)th Nc-bit c-DAI within the plurality of received Nc-bit c-DAIs, where m is a positive integer, C is 2^Nc, and floor is a round-down function; and Control information including the HARQ-ACK bit is transmitted via the PUSCH.

10. The method according to claim 9, wherein: The number of HARQ-ACK bits is based on a value O corresponding to 4*(floor(j*C / 4)+Q)+V, where -Q is 0 or 1, and -V is the value of the 2-bit UL-DAI and is in the range of 1 to 4.

11. The method according to claim 10, wherein: The number of HARQ-ACK bits is determined to be one of 0 and 2*0.

12. The method according to claim 10, wherein: Only when V is less than V temp When Q is 1, and Among them, V temp Determine a 2-bit c-DAI value converted from the value of the last one of the multiple received Nc-bit c-DAIs, so that the converted 2-bit c-DAI value corresponds to the number of downlink schedulings determined based on the multiple received Nc-bit c-DAIs.

13. The method according to claim 12, wherein: The value of the last of the plurality of received Nc-bit c-DAIs and the converted 2-bit c-DAI value satisfies the relationship comprised in the following table: Wherein, X represents the value of the last one of the multiple received Nc-bit c-DAIs, and Y represents the converted 2-bit c-DAI value.

14. The method according to claim 9, wherein The Nc-bit c-DAI is associated with the bit position of the corresponding HARQ-ACK bit in the HARQ-ACK bits.

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

16. The method according to claim 9, wherein The wireless communication system includes a wireless communication system based on the 3rd Generation Partnership Project (3GPP).

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