Method, apparatus and system for sending or receiving data channels and control channels

Abstract

The present invention relates to a method, apparatus, and system for transmitting or receiving a data channel and a control channel. Disclosed is a terminal of a wireless communication system and a wireless communication method using the terminal. More specifically, disclosed is a terminal and a wireless communication method using the terminal, the terminal including a communication module and a processor, wherein the processor: receives DCI via a PDCCH indicating PDSCH scheduling information of each of one or more cells; identifies a transmission scheme in each cell based on the DCI format of the DCI; receives the PDSCH of each of the one or more cells based on the scheduling information of the PDCCH; generates a HARQ-ACK bit sequence for the one or more cells based on the identified transmission scheme in each cell in response to receiving the PDSCH of each cell; and transmits the generated HARQ-ACK bit sequence.

Description

[0001] This application is a divisional application of the patent application with the application number 201880057581.9 (international application number PCT / KR2018 / 008917), the international filing date of which is August 6, 2018, and the invention title of which is "Method, apparatus, and system for transmitting or receiving a data channel and a control channel in a wireless communication system", and which was filed on March 5, 2020. Technical Field

[0002] The present invention relates to a wireless communication system. In particular, the present invention relates to a wireless communication method, apparatus, and system for transmitting and receiving a data channel and a control channel. Background Art

[0003] Since the commercialization of the fourth-generation (4G) communication system, efforts have been made to develop a new fifth-generation (5G) communication system to meet the increasing demand for wireless data services. The 5G communication system is referred to as a communication system that exceeds the 4G network communication system, a post-LTE system, or a new radio (NR) system. To achieve high data rates, the 5G communication system includes a system that operates in a super high frequency (e.g., millimeter wave) band above 6 GHz, and includes a communication system that operates in a band below 6 GHz to ensure coverage, such that implementation in a base station and a terminal is being considered.

[0004] The third-generation partnership project (3GPP) NR system improves the spectral efficiency of the network, enabling an operator to provide more data and voice services over a given bandwidth. As a result, in addition to supporting a large amount of voice, the 3GPP NR system is designed to meet the demand for high-speed data and multimedia transmission. The advantages of the NR system are to support high throughput, low latency, frequency division duplexing (FDD) and time division duplexing (TDD) on the same platform, an improved end-user experience, and a simple architecture with low operating costs.

[0005] For more efficient data processing, the dynamic TDD of the NR system can use a method of varying the number of orthogonal frequency division multiplexing (OFDM) symbols that can be used for uplink / downlink according to the data traffic direction of the cell users. For example, when the downlink traffic volume of the cell is greater than the uplink traffic volume, the base station can allocate multiple downlink OFDM symbols to a time slot (or subframe). Information about the time slot configuration should be sent to the terminal.

[0006] To mitigate the path loss of radio waves and increase the transmission distance of radio waves in the ultra-high frequency band, technologies such as beamforming, massive array multiple-input / multiple-output (massive MIMO), full-dimension MIMO (FD-MIMO), array antennas, analog beamforming, hybrid beamforming that combines analog beamforming and digital beamforming, and massive antennas are being discussed in 5G communication systems. Additionally, to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense networks, device-to-device communication (D2D), vehicle-to-everything communication (V2X), wireless backhaul, non-terrestrial network communication (NTN), mobile networks, mobile networking, cooperative communication, coordinated multipoint (CoMP), and interference cancellation are being developed in 5G communication systems. Furthermore, in 5G systems, advanced coding modulation (ACM) schemes such as hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access technologies such as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) are being developed.

[0007] Meanwhile, the Internet is evolving from a human-centric connection network where humans create and consume information into an Internet of Things (IoT) network that distributes components such as object exchange and information processing. Among them, the Internet of Everything (IoE) technology that combines big data processing technology into IoT through connection with cloud servers and the like is on the rise. To realize IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, and technologies such as sensor networks, machine-to-machine communication (M2M), and machine type communication (MTC) for connection between objects have been studied recently. In the IoT environment, intelligent Internet technology (IT) services that can collect and analyze data generated from connected objects and create new value in human life can be provided. By fusing and combining existing information technology (IT) and various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, advanced medical services, and so on.

[0008] Therefore, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine communication (M2M), and machine type communication (MTC) have been implemented through schemes such as beamforming, MIMO, and array antennas ((which are 5G communication technologies)). As the above-mentioned big data processing technology, cloud radio access network (cloud RAN) is an example of the integration of 5G technology and IoT technology. Generally, mobile communication systems have been developed to provide voice services while ensuring user activities.

[0009] However, mobile communication systems are gradually expanding not only in terms of voice but also in data services, and now they have developed to the extent that they can provide high-speed data services. However, in the current mobile communication systems providing services, due to resource shortages and the high-speed service demands of users, more advanced mobile communication systems are needed. SUMMARY OF THE INVENTION

[0010] TECHNICAL PROBLEM

[0011] An object of the present invention is to provide a method and apparatus for effectively transmitting signals in a wireless communication system (particularly a cellular wireless communication system). Another object of the present invention is to provide a method for transmitting and receiving a downlink control channel, and an apparatus and system for transmitting and receiving a downlink control channel.

[0012] An object of the present invention is to provide a method for generating a HARQ-ACK bit sequence when configured to enable codeblock group (CBG)-based transmission to a user equipment.

[0013] Furthermore, an object of the present invention is to provide a method capable of performing effective retransmission when configured to enable CBG-based transmission to a user equipment.

[0014] Furthermore, an object of the present invention is to provide a method for generating a HARQ-ACK bit sequence when a user equipment configured to enable CBG-based transmission fails to receive at least one PDCCH.

[0015] TECHNICAL SOLUTION

[0016] To solve the above problems, the present invention provides a user equipment of a wireless communication system and a wireless communication method as follows.

[0017] First, an exemplary embodiment of the present invention provides a user equipment of a wireless communication system, including a communication module; and a processor configured to control the communication module. The processor receives downlink control information (DCI) through a physical downlink control channel (PDCCH) indicating physical downlink shared channel (PDSCH) scheduling information of each cell in one or more cells. Among the one or more cells, at least one cell is configured for codeblock group (CBG)-based transmission. The transmission scheme in each cell is identified based on the DCI format of the DCI. The transmission scheme is either transport block (TB)-based transmission or CBG-based transmission. The PDSCH of each cell in the one or more cells is received based on the scheduling information of the PDCCH. In response to receiving the PDSCH of each cell, a hybrid automatic repeat request acknowledgement (HARQ-ACK) bit sequence for one or more cells is generated based on the identified transmission scheme of each cell. In the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for TB-based transmission and the HARQ-ACK bit sequence for CBG-based transmission are generated separately, and the generated HARQ-ACK bit sequence is transmitted.

[0018] In addition, an exemplary embodiment of the present invention provides a wireless communication method in a wireless communication system, including: receiving downlink control information (DCI) through a physical downlink control channel (PDCCH) indicating physical downlink shared channel (PDSCH) scheduling information of each cell in one or more cells, where at least one cell among the one or more cells is configured for codeblock group (CBG)-based transmission; identifying the transmission scheme in each cell based on the DCI format of the DCI, where the transmission scheme is either transport block (TB)-based transmission or CBG-based transmission; receiving the PDSCH of each cell in the one or more cells based on the scheduling information of the PDCCH; in response to receiving the PDSCH of each cell, generating a hybrid automatic repeat request acknowledgement (HARQ-ACK) bit sequence for one or more cells based on the identified transmission scheme of each cell, where in the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for TB-based transmission and the HARQ-ACK bit sequence for CBG-based transmission are generated separately, and transmitting the generated HARQ-ACK bit sequence.

[0019] One HARQ-ACK bit can be generated for each transport block in the HARQ-ACK bit sequence for TB-based transmission, and N HARQ-ACK bits can be generated for each transport block in the HARQ-ACK bit sequence for CBG-based transmission, and N can be the maximum number of CBGs configured for each transport block of the user equipment.

[0020] When the number M of codeblock groups (CBGs) transmitted via a specific cell that configures CBG-based transmission in one or more cells is less than N, the hybrid automatic repeat request acknowledgement (HARQ-ACK) bits for the specific cell may consist of M HARQ-ACK bits for the transmitted CBGs and N−M NACKs.

[0021] The processor may receive a downlink allocation index (DAI) in downlink control information (DCI) format, generate a HARQ-ACK bit sequence with reference to the DAI, and the DAI may include a counter-DAI indicating the cumulative number of physical downlink shared channels (PDSCHs) scheduled for the current cell and a total-DAI indicating the total number of PDSCHs scheduled for the entire cell.

[0022] The DAI may be separately applied to the HARQ-ACK bit sequence for transmission based on transport blocks (TBs) and the HARQ-ACK bit sequence for CBG-based transmission.

[0023] Within the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for CBG-based transmission may be appended to the HARQ-ACK bit sequence for TB-based transmission.

[0024] Next, another exemplary embodiment of the present invention provides a user equipment of a wireless communication system, including: a communication module; and a processor configured to control the communication module, wherein the processor receives a physical downlink control channel (PDCCH) indicating physical downlink shared channel (PDSCH) scheduling information for each of one or more cells, wherein CBG-based transmission is configured to be available in at least one of the one or more cells, receives a downlink allocation index (DAI) via the PDCCH, receives the PDSCH for each of the one or more cells based on the scheduling information of the PDCCH, generates a HARQ-ACK bit sequence for the one or more cells with reference to the DAI in response to receiving the PDSCH for each cell, wherein the HARQ-ACK bit sequence includes at least one of a HARQ-ACK bit sequence for transmission based on transport blocks (TBs) and a HARQ-ACK bit sequence for CBG-based transmission, and wherein the DAI is separately applied to the HARQ-ACK bit sequence for TB-based transmission and the HARQ-ACK bit sequence for CBG-based transmission, and transmits the generated HARQ-ACK bit sequence.

[0025] In addition, another exemplary embodiment of the present invention provides a wireless communication method in a wireless communication system, including: receiving a physical downlink control channel (PDCCH) indicating physical downlink shared channel (PDSCH) scheduling information of each cell in one or more cells, wherein transmission based on codeblock groups (CBGs) is configured to be available in at least one of the one or more cells; receiving a downlink allocation index (DAI) through the PDCCH; receiving the PDSCH of each cell in the one or more cells based on the scheduling information of the PDCCH; in response to receiving the PDSCH of each cell, generating a hybrid automatic repeat request acknowledgment (HARQ-ACK) bit sequence for the one or more cells with reference to the DAI, wherein the HARQ-ACK bit sequence includes at least one of a HARQ-ACK bit sequence for transmission based on transport blocks (TBs) and a HARQ-ACK bit sequence for transmission based on CBGs, and wherein the DAI is separately applied to the HARQ-ACK bit sequence for transmission based on TBs and the HARQ-ACK bit sequence for transmission based on CBGs, and transmitting the generated HARQ-ACK bit sequence.

[0026] The HARQ-ACK bit sequence can be generated based on the identified transmission scheme of each cell, and the transmission scheme of each cell can be transmission based on TBs or transmission based on CBGs.

[0027] The processor can receive downlink control information (DCI) through the PDCCH, and the transmission scheme of each cell can be identified based on the DCI format of the DCI.

[0028] One HARQ-ACK bit can be generated for each transport block in the HARQ-ACK bit sequence for transmission based on TBs, and N HARQ-ACK bits can be generated for each transport block in the HARQ-ACK bit sequence for transmission based on CBGs, and N can be the maximum number of CBGs per transport block configured for the user equipment.

[0029] When the number M of CBGs sent through a specific cell configured for transmission based on CBGs in one or more cells is less than N, the HARQ-ACK bits for the specific cell can be composed of M HARQ-ACK bits for the CBGs sent and N - M NACKs.

[0030] Within the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for transmission based on CBGs can be appended to the HARQ-ACK bit sequence for transmission based on TBs.

[0031] The DAI applied to TB-based transmission may include a counter-DAI indicating the cumulative number of TB-based PDSCHs scheduled to the current cell and a total-DAI indicating the total number of TB-based PDSCHs scheduled for the entire cell, and the DAI applied to CBG-based transmission may include a counter-DAI indicating the cumulative number of CBG-based PDSCHs scheduled to the current cell and a total-DAI indicating the total number of CBG-based PDSCHs scheduled for the entire cell.

[0032] When the total-DAI of the DAI applied to TB-based transmission indicates a predetermined value and no PDCCH scheduling TB-based transmission is received, the HARQ-ACK bit sequence may be configured to exclude the HARQ-ACK bits for TB-based transmission, and when the total-DAI of the DAI applied to CBG-based transmission indicates a predetermined value and no PDCCH scheduling CBG-based transmission is received, the HARQ-ACK bit sequence may be configured to exclude the HARQ-ACK bit sequence for CBG-based transmission.

[0033] The predetermined value may be binary "11".

[0034] The HARQ-ACK bit sequence may be transmitted through a Physical Uplink Shared Channel (PUSCH).

[0035] Advantageous Effects

[0036] According to an embodiment of the present invention, the overhead of downlink control information to be referred to by a user equipment configured to implement CBG-based transmission in determining the HARQ-ACK bit sequence can be minimized. Therefore, according to an embodiment of the present invention, the transmission efficiency of the network between a base station and a user equipment can be improved.

[0037] In addition, according to an embodiment of the present invention, the signaling overhead for retransmission requests can be minimized through effective signaling in a fallback mode.

[0038] The effects obtainable in the present invention are not limited to the above effects, and other effects not mentioned above can be clearly understood by those skilled in the art according to the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Illustrates an example of a radio frame structure used in a wireless communication system.

[0040] Figure 2 Illustrates an example of a downlink (DL) / uplink (UL) time slot structure in a wireless communication system.

[0041] Figure 3It is a schematic diagram showing physical channels used in a 3GPP system and a general signal transmission method using such physical channels.

[0042] Figure 4 It shows an SS / PBCH block for initial cell access in a 3GPP NR system.

[0043] Figure 5 It shows the process of transmitting control information and control channels in a 3GPP NR system.

[0044] Figure 6 It is a schematic diagram showing a control resource set (CORESET) in which a physical downlink control channel (PDCCH) can be transmitted in a 3GPP NR system.

[0045] Figure 7 It is a schematic diagram showing CCE aggregation search space allocation for a common search space and a UE-specific (or terminal-specific) search space.

[0046] Figure 8 It is a conceptual diagram showing carrier aggregation.

[0047] Figure 9 It is a schematic diagram for describing single-carrier communication and multi-carrier communication.

[0048] Figure 10 It is a schematic diagram showing an example of applying cross-carrier scheduling technology.

[0049] Figure 11 It shows a code block group (CBG) configuration according to an embodiment of the present invention and its time-frequency resource mapping.

[0050] Figure 12 It shows the process in which a base station performs TB-based transmission or CBG-based transmission according to an embodiment of the present invention and a user equipment performs HARQ-ACK transmission in response thereto.

[0051] Figure 13 It shows an embodiment of a method for explaining received HARQ-ACK feedback and a fallback indicator.

[0052] Figure 14 It shows another embodiment of a method for explaining received HARQ-ACK feedback and a fallback indicator.

[0053] Figure 15 It shows an example in which a user equipment transmits HARQ-ACK and a fallback indicator for a CBG according to the above embodiment.

[0054] Figures 16 to 19 It shows an additional embodiment in which a user equipment transmits HARQ-ACK and a fallback indicator for a CBG.

[0055] Figure 20 An embodiment showing the value of the downlink allocation index (DAI) mapped to each component carrier.

[0056] Figure 21 and Figure 22 An embodiment showing a DAI signaling method according to a first embodiment of the present invention and a method for generating a HARQ-ACK bit sequence based on the DAI signaling method.

[0057] Figure 23 An embodiment showing a DAI signaling method according to a second embodiment of the present invention.

[0058] Figure 24 An embodiment showing a DAI signaling method according to a third embodiment of the present invention.

[0059] Figure 25 and 26 An embodiment showing the generation of a HARQ-ACK bit sequence based on the DAI signaled according to the above third embodiment.

[0060] Figure 27 Another embodiment showing the generation of a HARQ-ACK bit sequence based on the DAI signaled according to the above third embodiment.

[0061] Figure 28 An embodiment showing a DAI signaling method according to a fourth embodiment of the present invention.

[0062] Figure 29 An embodiment showing a DAI signaling method according to a fifth embodiment of the present invention.

[0063] Figure 30 An embodiment showing a DAI signaling method according to a sixth embodiment of the present invention.

[0064] Figure 31 An embodiment showing the generation of a HARQ-ACK bit sequence based on the DAI signaled according to the above sixth embodiment.

[0065] Figure 32 An embodiment showing a DAI signaling method according to a seventh embodiment of the present invention.

[0066] Figure 33 An embodiment showing the generation of a HARQ-ACK bit sequence based on the DAI signaled according to the above seventh embodiment.

[0067] Figure 34 An embodiment showing a DAI signaling method according to an eighth embodiment of the present invention.

[0068] Figure 35 An embodiment showing a DAI signaling method according to a ninth embodiment of the present invention.

[0069] Figure 36 The figure illustrates an embodiment of generating a HARQ-ACK bit sequence by signaling DAI according to the ninth embodiment described above.

[0070] Figure 37 The figure illustrates a DAI signaling method according to the tenth embodiment of the present invention.

[0071] Figure 38 The figure illustrates a HARQ-ACK compression method according to an embodiment of the present invention.

[0072] Figure 39 and Figure 40 The figure illustrates a method of performing spatial bundling of HARQ-ACK according to an embodiment of the present invention.

[0073] Figure 41 and Figure 42 More specifically, the figure illustrates a method of performing spatial bundling of HARQ-ACK according to an embodiment of the present invention.

[0074] Figure 43 is a block diagram illustrating the configurations of a terminal and a base station according to an embodiment of the present invention. Detailed Description

[0075] The terms used in the specification are general terms, which are currently used as widely as possible by considering the functions in the present invention. However, these terms can be changed according to the intention of those skilled in the art, habits, and the emergence of new technologies. In addition, in specific cases, there are terms arbitrarily selected by the applicant, and in such cases, their meanings will be described in the corresponding description part of the present invention. Therefore, it is intended that the terms used in the specification should be analyzed not only based on the names of the terms, but also based on the substantial meanings of the terms and the content in the specification.

[0076] Throughout the specification and the following claims, when an element is described as being "connected" to another element, the element can be "directly connected" to the other element or "electrically connected" to the other element through a third element. In addition, unless explicitly described to the contrary, the word "comprising" will be understood to imply including the stated elements, but not excluding any other elements, unless otherwise stated. In addition, in some exemplary embodiments, limitations such as "greater than or equal to" or "less than or equal to" based on a specific threshold can be appropriately replaced with "greater than" or "less than", respectively.

[0077] The following technologies can be used in various wireless access systems, such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier - FDMA (SC - FDMA), etc. CDMA can be implemented by wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA 2000. TDMA can be implemented by radio 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 (i.e., Wi - Fi), IEEE 802.16 (i.e., WiMAX), IEEE 802 - 20, Evolved UTRA (E - UTRA), etc. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) is part of the Evolved UMTS (E - UMTS) that uses Evolved UMTS Terrestrial Radio Access (E - UTRA), and LTE - Advanced (LTE - 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 and low - latency communication (URLLC), and massive machine - type communication (mMTC) services, which are requirements of IMT - 2020. For clear description, 3GPP NR is mainly described, but the technical idea of the present invention is not limited thereto.

[0078] Unless otherwise specified in this specification, a base station may include a next - generation node B (gNB) as defined in 3GPP NR. In addition, unless otherwise explained, a terminal may include a user equipment (UE).

[0079] Figure 1 An example of a radio frame structure used in a wireless communication system is illustrated. Refer to Figure 1 , in the 3GPP NR system, a radio frame (or wireless frame) may have a length of 10 ms (Δf max N f / 100)*T c ). Additionally, a radio frame includes 10 sub - frames (SFs) of equal size. Here, Δf max = 480*10 3 Hz, N f = 4096, T c = 1 / (Δf ref *N f,ref ), Δf ref = 15*10 3 Hz, and N f,ref= 2048. The numbers from 0 to 9 can be respectively assigned to 10 subframes within a radio frame. Each subframe has a length of 1 ms and can include one or more time slots according to the subcarrier spacing. More specifically, in the 3GPP NR system, the subcarrier spacings that can be used are 15 * 2 μ kHz. μ can have values of μ = 0 to 4 as subcarrier spacing configurations. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 240 kHz can be used for the subcarrier spacing. A subframe with a length of 1 ms can be composed of 2 μ time slots. In such a case, the length of each time slot is 2 -μ ms. The numbers from 0 to 2 μ-1 can be respectively assigned to 2 μ time slots within a subframe. Additionally, the numbers from 0 to 10 * 2 μ - 1 can be respectively assigned to the time slots within a subframe. The time resources can be distinguished by at least one of the radio frame number (also referred to as the radio frame index), subframe number (also referred to as the subframe index), and time slot number (or time slot index).

[0080] Figure 2 FIG. shows an example of the downlink (DL) / uplink (UL) time slot structure in a wireless communication system. In particular, Figure 2 shows the structure of the resource grid of the 3GPP NR system. There is a resource grid for each antenna port. Referring to 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 means a symbol duration. Unless otherwise specified, an OFDM symbol can be simply referred to as a symbol. Referring to Figure 2 , the signal transmitted in each time slot can be represented by a resource grid including N size,μ grid,x * N RB sc subcarriers and N slot symb OFDM symbols. Here, for the downlink resource grid x = DL, and for the uplink resource grid x = UL. N size,μ grid,x represents the number of resource blocks according to the subcarrier spacing configuration μ (in such a case, x is DL or UL), and N slot symb represents the number of OFDM symbols in the time slot. N RB sc is the number of subcarriers constituting one RB and N RB sc= 12. According to the multiple access scheme, an OFDM symbol can be referred to as a cyclic prefix OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-S-OFDM) symbol.

[0081] The number of OFDM symbols included in a time slot can vary according to the length of the cyclic prefix (CP). For example, in the case of normal CP, a time slot includes 14 OFDM symbols, but in the case of extended CP, a time slot can include 12 OFDM symbols. In a specific embodiment, the extended CP can be used only with a 60 kHz subcarrier spacing. In Figure 2 for ease of description, as an example, a time slot includes 14 OFDM symbols, but embodiments of the present invention can be applied in a similar manner to time slots with different numbers of OFDM symbols. Refer to Figure 2 , each OFDM symbol includes N size,μ grid,x *N RB sc subcarriers in the frequency domain. The types of subcarriers can be divided into data subcarriers for data transmission, reference signal subcarriers for transmitting reference signals, and guard bands. The carrier frequency is also referred to as the center frequency (fc).

[0082] An RB can be defined by N RB sc (e.g., 12) consecutive subcarriers in the frequency domain. As a reference, a resource including one OFDM symbol and one subcarrier can be referred to as a resource element (RE) or a tone. Therefore, an RB can include 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, 1) in a time slot. k can be an index numbered from 0 to N size,μ grid,x *N RB sc -1 in the frequency domain, and 1 can be an index numbered from 0 to N slot symb -1 in the time domain.

[0083] In order for a user equipment to receive signals from a base station or transmit signals to a base station, the time / frequency synchronization of the user equipment can be synchronized with the time / frequency synchronization of the base station. This is because the base station and the user equipment need to be synchronized so that the user equipment can determine the time and frequency parameters required to demodulate DL signals and transmit UL signals at the correct time.

[0084] Each symbol of a radio frame in time division duplex (TDD) or unpaired spectrum operation can be configured as at least one of a DL symbol, a UL symbol, or a flexible symbol. A radio frame operating as a downlink carrier in frequency division duplex (FDD) or paired spectrum can consist of downlink symbols or flexible symbols, while a radio frame operating as an uplink carrier can consist of uplink symbols or flexible symbols. In a downlink symbol, downlink transmission is possible while uplink transmission is not, and in an uplink symbol, uplink transmission is possible while downlink transmission is not. A flexible symbol can be determined to be used as a downlink or an uplink according to a signal.

[0085] Information about the type of each symbol (i.e., information indicating any one of a downlink symbol, an uplink symbol, and a flexible symbol) can be configured by a cell-specific (or common) radio resource control (RRC) signal. Additionally, information about the type of each symbol can be configured by a UE-specific (or dedicated) RRC signal. The base station uses the cell-specific RRC signal to indicate i) the period of the cell-specific time slot configuration, ii) the number of time slots having only downlink symbols starting from the beginning of the period of the cell-specific time slot configuration, iii) the number of downlink symbols starting from the first symbol of the next time slot immediately following the time slot having only downlink symbols, iv) the number of time slots having only uplink symbols starting from the end of the period of the cell-specific time slot configuration, v) the number of uplink symbols starting from the last symbol of the time slot immediately preceding the time slot having only uplink symbols. Here, a symbol not configured as either an uplink symbol or a downlink symbol is a flexible symbol.

[0086] When information related to the symbol type is configured with a UE-specific RRC signal, the base station can signal whether the flexible symbol is a downlink symbol or an uplink symbol via a cell-specific RRC signal. In this case, the UE-specific RRC signal cannot change a downlink symbol or an uplink symbol configured by the cell-specific RRC signal to another symbol type. The UE-specific RRC signal can signal the number of downlink symbols among the N slot symb symbols of a corresponding time slot and the number of uplink symbols among the N slot symb symbols of the corresponding time slot for each time slot. In this case, the downlink symbols of a time slot can be configured continuously from the first symbol to the i-th symbol of the time slot. Additionally, the uplink symbols of a time slot can be configured continuously from the j-th symbol to the last symbol of the time slot (where i < j). A symbol not configured as either an uplink symbol or a downlink symbol in a time slot is a flexible symbol.

[0087] The type of symbol configured by the above RRC signal can be referred to as semi-static DL / UL configuration. In the previously configured semi-static DL / UL configuration by the RRC signal, the flexible symbol can be indicated to a downlink symbol, an uplink symbol, or a flexible symbol by the dynamic time slot format information (SFI) sent by the physical downlink control channel (PDCCH). In this case, the downlink symbol or uplink symbol configured by the RRC signal does not change to another symbol type. Table 1 illustrates the dynamic SFI that the base station can configure for the terminal.

[0088] [Table 1]

[0089]

[0090] In Table 1, D represents a downlink symbol, U represents an uplink symbol, and X represents a flexible symbol. As shown in Table 1, up to two DL / UL switches are allowed in one time slot.

[0091] Figure 3 It is a schematic diagram for explaining the physical channels used in a 3GPP system (e.g., NR) and the general signal transmission method using the physical channel. When the power of the user equipment is turned on or the user equipment enters a new cell, the user equipment performs initial cell search (S101). Specifically, the user equipment can synchronize with the base station during the initial cell search. To this end, the user equipment can receive the primary synchronization signal (PSS) and the secondary synchronization signal (SSS) from the base station, synchronize with the base station, and obtain information such as the cell ID. Thereafter, the user equipment can receive the physical broadcast channel from the base station and obtain the in-cell broadcast information.

[0092] After completing the initial cell search, the user equipment receives the physical downlink control channel (PDCCH) and receives the physical downlink shared channel (PDSCH) according to the information carried in the PDCCH, enabling the user equipment to obtain more specific system information than the system information obtained through the initial cell search (S102).

[0093] When the user equipment initially accesses the base station or has no radio resources for signal transmission, the user equipment can perform a random access procedure on the base station (S103 to S106). First, the user equipment can send a specific sequence as a preamble through the physical random access channel (PRACH) (S103), and receive a response message for the preamble from the base station on the PDCCH and the corresponding PDSCH (S104). In the case of contention-based RACH, a contention resolution process can be additionally performed.

[0094] After the above process, the user equipment receives PDCCH / PDSCH (S107) and transmits a Physical Uplink Shared Channel (PUSCH) / Physical Uplink Control Channel (PUCCH) (108) as a general phase / DL signal transmission process. Specifically, the user equipment can receive Downlink Control Information (DCI) through the PDCCH. The DCI can include control information such as resource allocation information for the user equipment. In addition, the format of the DCI can vary according to the intended use. The control information sent by the user equipment to the base station through the uplink includes DL / UL ACK / NACK signals, Channel Quality Indicator (CQI), Precoding Matrix Index (PMI), and Rank Indicator (RI). In this case, the CQI, PMI, and RI can be included in the Channel State Information (CSI). In the 3GPP NR system, the user equipment can send control information such as the above-mentioned HARQ-ACK and CSI through the PUSCH and / or PUCCH.

[0095] Figure 4 FIG. shows an SS / PBCH block for initial cell access in the 3GPP NR system. When the power of the user equipment is turned on and the user equipment attempts to access a new cell, the user equipment can obtain time and frequency synchronization with the cell and perform an initial cell search process. The user equipment is capable of detecting the physical cell identity N of the cell during the initial cell search process. cell ID For this purpose, the user equipment can receive synchronization signals (e.g., Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS)) from the base station and synchronize with the base station. In this case, the user equipment can obtain information such as the cell identity (ID).

[0096] Reference Figure 4 (a), the synchronization signal (SS) will be described in more detail. The synchronization signal can be divided into PSS and SSS. The PSS can be used to obtain time-domain synchronization and / or frequency-domain synchronization, such as OFDM symbol synchronization and slot synchronization. The SSS can be used to obtain frame synchronization and cell group ID. Reference Figure 4(a) and Table 2, the SS / PBCH block consists of 20 consecutive RBs (= 240 subcarriers) in the frequency axis and 4 consecutive OFDM symbols in the time axis. Here, in the SS / PBCH block, the PSS in the first OFDM symbol and the SSS in the third OFDM symbol are transmitted through subcarriers 56 to 182. Here, the lowest subcarrier index of the SS / PBCH block is numbered starting from 0. In the first OFDM symbol transmitting the PSS, the base station does not transmit signals through the remaining subcarriers (i.e., subcarriers 0 to 55 and 183 to 239). In the third OFDM symbol transmitting the SSS, the base station does not transmit signals through subcarriers 48 to 55 and 183 to 191. In the SS / PBCH block, in addition to the above signals, the base station transmits the physical broadcast channel (PBCH) signal through the remaining REs.

[0097] [Table 2]

[0098]

[0099] The SS can represent a total of 1008 unique physical layer cell IDs through combinations of 3 PSSs and SSSs. Specifically, each physical layer cell ID is grouped into 336 physical layer cell identifier groups, where each group includes 3 unique identifiers, such that each physical layer cell ID is only part of one physical layer cell identifier group. Thus, the physical layer cell ID N cell ID = 3N (1) ID + N (2) ID ID can be defined by an index N indicating the range of the physical layer cell identifier group from 0 to 335 (1) ID and an index N indicating the range of the physical layer identifier within the physical layer cell identifier group from 0 to 2 (2) ID The user equipment can detect the PSS and identify one of the three unique physical layer identifiers. Additionally, the user equipment can detect the SSS and identify one of the 336 physical layer cell IDs associated with the physical layer identifier. In such a case, the sequence d PSS (n) is as follows.

[0100]

[0101] Here, x(i + 7) = (x(i + 4) + x(i)) mod 2, and

[0102] [x(6) x(5) x(4) x(3) x(2) x(1) x(0)] = [1 1 1 0 1 1 0]

[0103] In addition, the sequence d of the SSS PSS (n) is as follows.

[0104]

[0105] Here, x1(i + 7) = (x1(i + 1) + x1(i)) mod 2, and

[0106] [x0(6) x0(5) x0(4) x0(3) x0(2) x0(1) x0(0)] = [0 0 0 0 0 0 1]

[0107] [x1(6) x1(5) x1(4) x1(3) x1(2) x1(1) x1(0)] = [0 0 0 0 0 0 1]

[0108] A radio frame having a length of 10 ms can be divided into two half - frames having a length of 5 ms. Refer to Figure 4(b) will describe the time slots in which the SS / PBCH block is transmitted in each half-frame. The time slots in which the SS / PBCH block is transmitted can be any one of cases A, B, C, D, and E. In case A, the subcarrier spacing is 15 kHz and the starting time point of the SS / PBCH block is {2,8}+ the 14*n-th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0, 1. Additionally, at a frequency above 3 GHz and below 6 GHz, n = 0, 1, 2, or 3. In case B, the subcarrier spacing is 30 kHz, and the starting time point of the SS / PBCH block is {4,8,16,20}+ the 28*n-th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0, 1. Additionally, at a frequency above 3 GHz and below 6 GHz, n = 0 or 1. In case C, the subcarrier spacing is 30 kHz, and the starting time point of the SS / PBCH block is {2,8}+ the 14*n-th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0 or 1. Additionally, at a frequency above 3 GHz and below 6 GHz, n = 0, 1, 2, or 3. In case D, the subcarrier spacing is 120 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 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, or 18. In case E, the subcarrier spacing is 240 kHz and the starting time point of the SS / PBCH block is {8,12,16,20,32,36,40,44}+ the 56*n-th symbol. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, or 8.

[0109] Figure 5 The figure illustrates the process for the transmission of control information and control channels in the 3GPP NR system. Refer to Figure 5(a), the base station may add a Cyclic Redundancy Check (CRC) masked with a Radio Network Temporary Identifier (RNTI) (e.g., XOR operation) to control information (e.g., Downlink Control Information, DCI) (S202). The base station may scramble the CRC using an RNTI value determined according to the purpose / target of each control information. The common RNTI used by one or more terminals may 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). Additionally, 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 (S206) according to the amount of resources for PDCCH transmission after performing channel coding (e.g., polar coding) (S204). Subsequently, the base station may multiplex the DCI based on the Physical Downlink Control Channel (PDCCH) structure based on Control Channel Elements (CCEs) (S208). In addition, the base station applies additional processes such as scrambling, modulation (e.g., QPSK), and interleaving to the multiplexed DCI (S210), and then maps it to the resources to be transmitted. A CCE is the basic resource unit for the PDCCH, and one CCE may be composed of multiple (e.g., six) Resource Element Groups (REGs). One REG may be composed of multiple (e.g., 12) Resource Elements (REs). The number of CCEs for one PDCCH may be defined as the aggregation level. In the 3GPP NR system, aggregation levels of 1, 2, 4, 8, or 16 may be used. Figure 5 (b) is a schematic diagram illustrating the CCE aggregation level and PDCCH multiplexing. In this case, the type of CCE aggregation level for one PDCCH is described and the CCEs transmitted accordingly in the control region are described.

[0110] Figure 6 is a schematic diagram illustrating a Control Resource Set (CORESET) in which a Physical Downlink Control Channel (PDCCH) in the 3GPP NR system may be transmitted. A CORESET is the time-frequency resource in which the PDCCH (i.e., the control signal for the user equipment) is transmitted. Additionally, the search space described below may be mapped to one CORESET. Thus, the user equipment may decode the PDCCH mapped to the CORESET by monitoring the time-frequency region designated as the CORESET instead of monitoring all frequency bands for PDCCH reception. The base station may configure one or more CORESETs for each cell for the user equipment. The CORESET may be configured with up to three consecutive symbols on the time axis. Additionally, the CORESET may be configured in units of 6 consecutive Physical Resource Blocks (PRBs) on the frequency axis. In Figure 5In an embodiment, CORESET #1 is configured with consecutive PRBs, and CORESET #2 and CORESET #3 are configured with non - consecutive PRBs. A CORESET can be located in any symbol of a time slot. For example, in Figure 5 the embodiment, CORESET #1 starts from the first symbol of the time slot, CORESET #2 starts from the fifth symbol of the time slot, and CORESET #9 starts from the ninth symbol of the time slot.

[0111] Figure 7 is a schematic diagram showing a method for setting up a PDCCH search space in a 3GPP NR system. To send a PDCCH to a user equipment, each CORESET can have at least one search space. In an embodiment of the present invention, a search space is all the time - frequency resource combinations (hereinafter referred to as the PDCCH candidate set) through which a PDCCH of the user equipment can be sent. The search space can include a common search space that all user equipments in a cell belonging to the same base station must jointly perform a search on, and a UE - specific or terminal - specific search space that a specific user equipment must perform a search on. In the common search space, all user equipments that can monitor a cell belonging to the same base station are jointly set to search for the PDCCH. In the common search space, it is set to monitor the PDCCH. In addition, in the UE - specific search space, each user equipment can be set to monitor the PDCCH allocated to each user equipment in different search space positions according to the user equipment. Since the control region to which a PDCCH can be allocated is limited, the corresponding UE - specific search space can partially overlap with the search spaces of other user equipments. Monitoring the PDCCH includes blindly decoding PDCCH candidates in the search space. The case of successful blind decoding can be expressed as (successfully) detecting / receiving the PDCCH. In addition, the case of failed blind decoding can be expressed as not detecting / receiving the PDCCH or can be expressed as not successfully detecting / receiving the PDCCH.

[0112] For ease of explanation, a PDCCH scrambled with a known group - common (GC) RNTI for sending UL control information to one or more user equipments is called a group - common (GC) PDCCH or a common PDCCH. In addition, a PDCCH scrambled with a UE - specific RNTI known to a specific user equipment for sending UL scheduling information or DL scheduling information to a specific user equipment is called a UE - specific PDCCH. The common PDCCH can be included in the common search space, and the UE - specific PDCCH can be included in the common search space or the UE - specific PDCCH.

[0113] The base station may signal to each user equipment or group of user equipments via the PDCCH at least one of information related to resource allocation (i.e., DL grant) of the paging channel (PCH) and the downlink shared channel (DL-SCH) or information related to resource allocation (i.e., UL grant) of the UL-SCH and HARQ information. The base station may transmit the PCH transport block and the DL-SCH transport block via the PDSCH. The base station may transmit data other than specific control information or specific service data via the PDSCH. Additionally, the user equipment may receive data other than specific control information or specific service data via the PDSCH.

[0114] The base station may include in the PDCCH information on which user equipment (one or more user equipments) to send the PDSCH data to and how the corresponding user equipment is to receive and decode the PDSCH data, and transmit the PDCCH. For example, assume that the DCI transmitted via a specific PDCCH is CRC masked with an RNTI called "A", and the DCI indicates that the PDSCH is allocated to radio resources (e.g., frequency position) called "B" and indicates transmission format information (e.g., transport block size, modulation scheme, coding information, etc.) called "C". The user equipment monitors the PDCCH using the RNTI information that the user equipment has. In this case, when there is a user equipment that blindly decodes the PDCCH with the "A" RNTI, the corresponding user equipment receives the PDCCH and receives the PDSCH indicated by "B" and "C" via the information of the received PDCCH.

[0115] Table 3 illustrates an embodiment of the physical uplink control channel (PUCCH) used in a wireless communication system.

[0116] [Table 3]

[0117] PUCCH format Length in OFDM symbol Number of bits 0 1-2 ≤2 1 4-14 ≤2 2 1-2 >2 3 4-14 >2 4 4-14 >2

[0118] The PUCCH may be used to transmit the following uplink control information (UCI).

[0119] - Scheduling Request (SR): Information for requesting UL UL-SCH resources.

[0120] - HARQ-ACK: Response to PDCCH (which indicates DL SPS release) and / or response to DL transport block (TB) on PDSCH. HARQ-ACK indicates whether the information sent via PDCCH or PDSCH has been received. HARQ-ACK responses include positive ACK (referred to as ACK for short), negative ACK (hereinafter referred to as NACK), discontinuous transmission (DTX), or NACK / DTX. Here, the term HARQ-ACK can be used interchangeably with HARQ ACK / NACK and ACK / NACK. Generally, ACK can be represented by the bit value 1, and NACK can be represented by the bit value 0.

[0121] - Channel State Information (CSI): This is feedback information about the DL channel. It is generated by the user equipment based on the CSI reference signal (RS) sent by the base station. Multi-Input Multi-Output (MIMO) related feedback information includes rank indicator (RI) and precoding matrix indicator (PMI). CSI can be divided into CSI part 1 and CSI part 2 according to the information indicated by CSI.

[0122] In the 3GPP NR system, five PUCCH formats can be used to support various service scenarios, various channel environments, and frame structures.

[0123] PUCCH format 0 is a format that can transmit 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 can be sent through one or two OFDM symbols on the time axis and one RB on the frequency axis. When PUCCH format 0 is sent with two OFDM symbols, the same sequence for the two symbols can be sent through different RBs. Thus, the user equipment can obtain frequency diversity gain. More specifically, the user equipment can determine the value of cyclic shift m bit for M bit bits of UCI (M cs = 1 or 2), and map the sequence obtained by cyclically shifting the basic sequence of length 12 by a predetermined value m cs to 12 REs of one OFDM symbol and one PRB and send it. When the number of available cyclic shifts for the user equipment is 12 and M bit = 1, 1-bit UCI 0 and UCI 1 can be represented by sequences corresponding to two cyclic shifts with a cyclic shift value difference of 6. Additionally, when M bit = 2, then 2-bit UCI 00, 01, 11, 10 can be represented by sequences corresponding to four cyclic shifts with a cyclic shift value difference of 3.

[0124] PUCCH format 1 can transmit 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 can be sent through consecutive OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 can be one of 4 to 14. More specifically, M bit UCI with M bits = 1 can be modulated with BPSK. The user equipment can modulate UCI with M

[0125] = 2 with quadrature phase shift keying (QPSK). The signal is obtained by multiplying the modulated complex-valued symbol d(0) by a sequence of length 12. The user equipment transmits the obtained signal by using the time-axis orthogonal cover code (OCC) to extend the even-numbered OFDM symbols assigned with PUCCH format 1. PUCCH format 1 determines the maximum number of different user equipments multiplexed in the same RB according to the length of the OCC to be used. In the odd-numbered OFDM symbols of PUCCH format 1, the demodulation reference signal (DMRS) is extended with OCC and mapped. bit bits of UCI (M bit > 2) are bit-level scrambled, QPSK modulated and mapped to the RBs of one or more OFDM symbols. Here, the number of RBs can be any one of 1 to 16.

[0126] PUCCH format 3 or PUCCH format 4 can transmit more than 2 bits of UCI. PUCCH format 3 or PUCCH format 4 can be sent through consecutive OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 can be one of 4 to 14. Specifically, the user equipment modulates M bit bits of UCI (M bit > 2) with π / 2-binary phase shift keying (BPSK) or QPSK to generate complex-valued symbols d(0) to d(Msymb-1). Here, when using π / 2-BPSK, M symb = M bit , and when using QPSK, M symb = M bitWhen it is / 2, the user equipment may not apply block extension to PUCCH format 3. However, the user equipment may apply block extension to one RB (i.e., 12 subcarriers) using a PreDFT-OCC of length 12, such that PUCCH format 4 can have two or four multiplexing capacities. The user equipment performs transmit precoding (or DFT precoding) on the extended signal and maps it to each RE to transmit the extended signal.

[0127] In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 can be determined according to the length and maximum code rate of the UCI sent by the user equipment. When the user equipment uses PUCCH format 2, the user equipment can send HARQ-ACK information and CSI information together through the PUCCH. When the number of RBs that the user equipment can send is greater than the maximum number of RBs that PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the user equipment can only send the remaining UCI information according to the priority of the UCI information without sending some UCI information.

[0128] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured by an RRC signal to indicate frequency hopping in a time slot. When frequency hopping is configured, the index of the RBs to be frequency-hopped can be configured using an RRC signal. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is sent through N OFDM symbols on the time axis, the first hop can have floor(N / 2) OFDM symbols, and the second hop can have ceil(N / 2) OFDM symbols.

[0129] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured to be repeatedly sent in multiple time slots. In this case, the number K of time slots for repeatedly sending the PUCCH can be configured by an RRC signal. The PUCCH that needs to be repeatedly sent starts at the OFDM symbol at the same position in each time slot and has the same length. When any one of the OFDM symbols in the OFDM symbols of the time slot in which the user equipment needs to send the PUCCH is indicated as a DL symbol by an RRC signal, the user equipment may not send the PUCCH in the corresponding time slot and delay the transmission of the PUCCH to the next time slot to send the PUCCH.

[0130] Meanwhile, in the 3GPP NR system, a user equipment is capable of performing transmission / reception using a bandwidth less than or equal to the bandwidth of a carrier (or cell). To this end, the user equipment may be configured with a bandwidth part (BWP) consisting of a contiguous bandwidth that is part of the bandwidth of the carrier. A user equipment operating according to TDD operation or in unpaired spectrum may be configured with up to four DL / UL BWP pairs in one carrier (or cell). Additionally, the user equipment may activate one DL / UL BWP pair. A user equipment operating according to FDD operation or in paired spectrum may receive up to four DL BWPs on a DL carrier (or cell) and up to four UL BWPs on a UL carrier (or cell). The user equipment may activate one DL BWP and one UL BWP for each carrier (or cell). The user equipment may or may not perform reception or transmission in time-frequency resources other than the activated BWP. The activated BWP may be referred to as an active BWP.

[0131] A base station may use downlink control information (DCI) to indicate to the user equipment the activated BWP among the configured BWPs. The BWP indicated by the DCI is activated and the other configured BWPs are deactivated. In a carrier (or cell) operating according to TDD operation, the base station may include a bandwidth part indicator (BPI) that indicates the BWP to be activated in the DCI scheduling the PDSCH or PUSCH to change the DL / UL BWP pair of the user equipment. The user equipment may receive the DCI scheduling the PDSCH or PUSCH and may identify the DL / UL BWP pair activated based on the BPI. For a DL carrier (or cell) operating as FDD operation, the base station may include a BPI that indicates the BWP to be activated in the DCI scheduling the PDSCH to change the DL BWP of the user equipment. For a UL carrier (or cell) operating as FDD operation, the base station may include a BPI that indicates the BWP to be activated in the DCI scheduling the PUSCH to change the UL BWP of the user equipment.

[0132] Figure 8 is a conceptual diagram illustrating carrier aggregation. Carrier aggregation is a method in which a user equipment uses multiple frequency blocks or cells (in a logical sense) including UL resources (or component carriers) and / or DL resources (or component carriers) as one large logical frequency band so that a wireless communication system can use a wider frequency band. Hereinafter, for ease of description, the term "component carrier" is used.

[0133] Reference Figure 8 , as an example of the 3GPP NR system, the total system bandwidth includes up to 16 component carriers, and each component carrier may be capable of having a bandwidth of up to 400 MHz. A component carrier may include one or more physically contiguous subcarriers. Although in Figure 8It is shown that each component carrier has the same bandwidth, but this is only an example, and each component carrier can have a different bandwidth. Moreover, although each component carrier is shown as adjacent to each other on the frequency axis, the drawings illustrate a logical concept, and each component carrier can be physically adjacent to each other or can be spaced apart.

[0134] Different center frequencies can be used for each component carrier. Moreover, a common center frequency can be used in physically adjacent component carriers. Assume that Figure 8 in an embodiment where all component carriers are physically adjacent, center frequency A can be used in all component carriers. Additionally, assume that the individual component carriers are not physically adjacent to each other, then center frequency A and center frequency B can be used in each component carrier.

[0135] When expanding the total system bandwidth through carrier aggregation, the frequency band used for communicating with each user equipment can be defined in units of component carriers. User equipment A can use 100 MHz, which is the total system bandwidth, and perform communication using all five component carriers. User equipments B1 to B5 can only use a 20 MHz bandwidth and perform communication using one component carrier. User equipments C1 and C2 can use a 40 MHz bandwidth and perform communication using two component carriers respectively. The two component carriers can be logically / physically adjacent or not adjacent. In Figure 8 the embodiment, user equipment C1 uses two non-adjacent component carriers, and user equipment C2 uses two adjacent component carriers.

[0136] Figure 9 is a schematic diagram for explaining single-carrier communication and multi-carrier communication. In particular, Figure 9 (a) shows the single-carrier subframe structure and Figure 9 (b) shows the multi-carrier subframe structure.

[0137] Referring to Figure 9 (a), in the case of the FDD mode, a general wireless communication system can perform data transmission or reception through one DL frequency band and a corresponding UL frequency band. In another specific embodiment, in the case of the TDD mode, the wireless communication system can divide the radio frame into UL time units and DL time units in the time domain, and perform data transmission or reception through the UL / DL time units. Referring to Figure 9 (b), three 20 MHz component carriers (CCs) can be aggregated into UL and DL respectively, so that a 60 MHz bandwidth can be supported. Each CC can be adjacent or not adjacent to each other in the frequency domain. Figure 9(b) shows a case where the bandwidth of the UL CC is the same as and symmetric to that of the DL CC, 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 CCs assigned / configured to a specific user equipment through RRC can be referred to as the serving UL / DL CCs of the specific user equipment.

[0138] The base station can communicate with the user equipment by activating some or all of the serving CCs of the user equipment or by deactivating some CCs. The base station is capable of changing the CCs to be activated / deactivated and the number of CCs to be activated / deactivated. If the base station assigns the CCs available to the user equipment as specific to a cell or specific to the UE, at least one of the assigned CCs is deactivated, unless the CC assignment of the user equipment is completely reconfigured or the user equipment is in handover. One CC that is not deactivated by the user equipment is called the primary CC (PCC) or the primary cell (PCell), and the CCs that the base station can freely activate / deactivate are called the secondary CCs (SCCs) or the secondary cells (SCells).

[0139] Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined by a combination of DL resources and UL resources (i.e., a combination of DL CCs and UL CCs). A cell can be configured separately with DL resources or a combination of DL resources and UL resources. If carrier aggregation is supported, the link between the carrier frequency of the DL resources (or DL CCs) and the carrier frequency of the UL resources (or UL CCs) can be indicated through 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, and the cell corresponding to the SCC is called the SCell. The carrier corresponding to the PCell in the downlink is the DL PCC, and the carrier corresponding to the PCell in the uplink is the UL PCC. Similarly, the carrier corresponding to the SCell in the downlink is the DL SCC, and the carrier corresponding to the SCell in the uplink is the UL SCC. Depending on the capabilities of the user equipment, the serving cell can consist of one PCell and zero or more SCells. When the user equipment is in the RRC_CONNECTED state but not configured for carrier aggregation or does not support carrier aggregation, there is only one serving cell configured with the PCell.

[0140] As described above, the term "cell" used in carrier aggregation is different from the term "cell" that refers to a specific geographical area provided with communication services by a base station or an antenna group. To distinguish between the cell referring to a specific geographical area and the cell in carrier aggregation, in the present invention, the cell in carrier aggregation is called a CC, and the cell in the geographical area is called a cell.

[0141] Figure 10It is a schematic diagram showing an example of applying cross-carrier scheduling technology. When cross-carrier scheduling is configured, the control channel transmitted through the first CC can use the Carrier Indicator Field (CIF) to schedule the data channel transmitted through the first CC or the second CC. The CIF is included in the DCI. In other words, the scheduling cell is configured, and the DL grant / UL grant transmitted 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 within the PDCCH area of the scheduling cell. The PCell is basically the scheduling cell, and a specific SCell can be designated as the scheduling cell by the upper layer.

[0142] In Figure 10 the embodiment of, it is assumed that 3 DL CCs are aggregated. Here, it is assumed that DL component carrier #0 is the DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are DL SCCs (or SCells). It is also assumed that the DL PCC is set as the PDCCH monitoring CC. If cross-carrier scheduling is not configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, the CIF is disabled, and according to the NR PDCCH rules, the PDCCH that can only transmit the PDSCH scheduling itself without CIF in each DL CC (non-cross-carrier scheduling, self-carrier scheduling). On the other hand, if cross-carrier scheduling is configured through UE-specific (or UE-specific group or cell-specific) higher layer signaling, the CIF is enabled, and the PDCCH that can transmit the PDSCH scheduling another CC by using the CIF and the PDCCH that transmits the PDSCH scheduling DL CC A in a specific CC can be sent (cross-carrier scheduling). On the other hand, no PDCCH is sent in other DL CCs. Therefore, depending on whether cross-carrier scheduling is configured for the user equipment, the user equipment receives the self-carrier scheduling PDSCH by monitoring the PDCCH that does not include the CIF, or receives the cross-carrier scheduling PDSCH by monitoring the PDCCH that includes the CIF.

[0143] Meanwhile, Figure 9 and 10 illustrates the subframe structure of the 3GPP LTE-A system, but 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 are replaced by time slots.

[0144] Figure 11 Illustrates the code block group (CBG) configuration and its time-frequency resource mapping according to an embodiment of the present invention. More specifically, Figure 11 (a) Illustrates an embodiment of the CBG configuration included in one transport block (TB), and Figure 11(b) Illustrates the time-frequency resource mapping of the corresponding CBG configuration.

[0145] Define the maximum supported length of the channel code. For example, the maximum supported length of the turbo code used in 3GPP LTE(-A) is 6144 bits. However, the length of the transport block (TB) transmitted in the PDSCH can be longer than 6144 bits. If the length of the TB is greater than the maximum supported length, the TB can be divided into code blocks (CBs) with a length of up to 6144 bits. Each CB is a unit in which channel encoding is performed. Additionally, several CBs can be bundled together to form a CBG for efficient retransmission. The user equipment and the base station need information on how to configure the CBG.

[0146] The CBGs and CBs within the TB can be configured according to various embodiments. According to an embodiment, the number of available CBGs can be determined as a fixed value or can be configured by the RRC configuration information between the base station and the user equipment. In this case, the number of CBs is determined according to the length of the TB, and the CBGs can be set according to the determined number information. According to another embodiment, the number of CBs that can be included in one CBG can be determined as a fixed value or can be configured by the RRC configuration information between the base station and the user equipment. In this case, when the number of CBs is determined according to the length of the TB, the number of CBGs can be set according to the information on the number of CBs in each CBG.

[0147] Reference Figure 11 Referring to the embodiment of (a), one TB can be divided into 8 CBs. The 8 CBs can be grouped again into 4 CBGs. The mapping relationship (or CBG configuration) between the CBs and the CBGs can be set statically between the base station and the user equipment or semi-statically using the RRC configuration information. According to another embodiment, the mapping relationship can be established through dynamic signaling. When the user equipment receives the PDCCH sent by the base station, the user equipment can directly or indirectly identify the mapping relationship (or CBG configuration) between the CBs and the CBGs through explicit information and / or implicit information. One CBG can include only one CB or can include all the CBs that make up one TB. As a reference, the techniques proposed in the embodiments of the present invention can be applied regardless of the configuration of the CBs and the CBGs.

[0148] Reference Figure 11(b), map the CBGs that make up a TB to the time-frequency resources for scheduling the PDSCH. According to an embodiment, each CBG can first be assigned to the frequency axis and then be extended to the time axis. When a PDSCH consisting of a TB containing 4 CBGs is assigned to 7 OFDM symbols, CBG0 can be transmitted through the first and second OFDM symbols, CBG1 can be transmitted through the second, third, and fourth OFDM symbols, CBG2 can be transmitted through the fourth, fifth, and sixth OFDM symbols, and CBG3 can be transmitted through the sixth and seventh OFDM symbols. The time-frequency mapping relationship assigned to the CBGs and the PDSCH can be pre-determined between the base station and the user equipment. However, Figure 11 The mapping relationship shown in (b) is for explaining the embodiments of the present invention, and the techniques proposed in the embodiments of the present invention can be applied regardless of the time-frequency mapping relationship of the CBGs.

[0149] Figure 12 Illustrate the process of a transmission in which a base station performs TB-based transmission or CBG-based transmission according to an embodiment of the present invention and a user equipment performs HARQ-ACK transmission in response thereto. Refer to Figure 12 , the base station can configure a transmission scheme suitable for the user equipment between TB-based transmission and CBG-based transmission. The user equipment can send HARQ-ACK bits according to the transmission scheme configured by the base station through the PUCCH or PUSCH. The base station can configure the PDCCH to schedule the PDSCH to be sent to the user equipment. The PDCCH can schedule TB-based transmission and / or CBG-based transmission. For example, one TB or two TBs can be scheduled in the PDCCH. If one TB is scheduled, the user equipment should feedback 1-bit HARQ-ACK. If two TBs are scheduled, 2-bit HARQ-ACK should be feedback for the two TBs. To eliminate the ambiguity between the base station and the user equipment, there can be a preset order between each bit of the 2-bit HARQ-ACK and the two TBs. As a reference, when the MIMO transmission rank or layer is low, one TB can be sent in one PDSCH. When the MIMO transmission rank or layer is high, two TBs can be sent in one PDSCH.

[0150] The user equipment may send HARQ-ACK based on 1-bit per TB to notify the base station whether the reception of each TB is successful. To generate HARQ-ACK for a TB, the user equipment may check the reception error of the corresponding TB through TB-CRC. If the TB-CRC for the TB is successfully checked, the user equipment generates ACK for the HARQ-ACK of the corresponding TB. However, if a TB-CRC error occurs for the TB, the user equipment generates NACK for the HARQ-ACK of the corresponding TB. The user equipment sends the TB-based HARQ-ACK generated as described above to the base station. The base station retransmits the TBs that respond to NACK among the TB-based HARQ-ACKs received from the user equipment.

[0151] In addition, the user equipment may send HARQ-ACK based on 1-bit per CBG to notify the base station whether the reception of each CBG is successful. To generate HARQ-ACK for a CBG, the user equipment may decode all CBs included in the CBG and check the reception error of each CB through CB-CRC. If the user equipment successfully receives all CBs that make up a CBG (i.e., when all CB-CRCs are successfully checked), the user equipment generates ACK for the HARQ-ACK of the corresponding CBG. However, if the user equipment fails to successfully receive at least one of the CBs that make up a CBG (i.e., at least one CB-CRC error occurs), the user equipment generates NACK for the HARQ-ACK of the corresponding CBG. The user equipment sends the CBG-based HARQ-ACK generated as described above to the base station. The base station retransmits the CBGs that respond to NACK among the CBG-based HARQ-ACKs received from the user equipment. According to an embodiment, the CB configuration of the retransmitted CBG may be the same as the CB configuration of the previously transmitted CBG. The length of the CBG-based HARQ-ACK bits sent from the user equipment to the base station may be determined based on the number of CBGs sent through PDSCH or the maximum number of CBGs configured by the RRC signal. In addition, the TB-based HARQ-ACK may be sent separately from the CBG-based HARQ-ACK, as in the above embodiment. In this case, the TB-based HARQ-ACK may indicate whether the TB-CRC is successfully checked.

[0152] According to an embodiment of the present invention, CBG-based HARQ-ACK feedback can be used for successful transmission of a TB. The base station can instruct the user equipment to send CBG-based HARQ-ACK. In this case, a retransmission scheme based on CBG-based HARQ-ACK can be used. The CBG-based HARQ-ACK can be sent through the PUCCH. Additionally, when the UCI is configured to be sent through the PUSCH, the CBG-based HARQ-ACK can be sent through the corresponding PUSCH. The configuration of the HARQ-ACK resources in the PUCCH can be configured through the RRC signal. Additionally, the actually sent HARQ-ACK resources can be indicated through the PDCCH that schedules the PDSCH sent based on CBG. The user equipment can send the HARQ-ACK for successfully receiving the sent CBG through one PUCCH resource indicated by the PDCCH among the PUCCH resources configured with the RRC.

[0153] The base station can identify whether the user equipment has successfully received the CBG sent to the user equipment through the CBG-based HARQ-ACK feedback of the user equipment. That is, through the HARQ-ACK for each CBG received from the user equipment, the base station can identify the CBG that the user equipment has successfully received and the CBG that the user equipment has failed to receive. The base station can perform CBG retransmission based on the received CBG-based HARQ-ACK. More specifically, the base station can only bundle and retransmit the CBG that responds to the HARQ-ACK with reception failure in one TB. In this case, the CBG that has responded to the successfully received HARQ-ACK is excluded from the retransmission. The base station can schedule the retransmitted CBG to a PDSCH and send it to the user equipment.

[0154] The number of CBGs sent through the PDSCH can vary during the CBG retransmission process for transmitting one TB. Therefore, the user equipment needs to send, through the HARQ-ACK, information on whether the reception of the CBG sent in the corresponding PDSCH is successful. However, the user equipment does not need to send the HARQ-ACK of the CBG that has already been responded with ACK and has not been retransmitted in the corresponding PDSCH. As described above, the HARQ-ACK bits can be reduced according to the number of CBGs sent in the PDSCH. By doing so, not only can the reliability of the HARQ-ACK be improved, but the unused HARQ-ACK resources can also be reused as the HARQ-ACK resources corresponding to other TBs or different TBs of the same user equipment, thereby reducing the overhead of the uplink control channel. However, despite the above advantages, the method of sending HARQ-ACK bits according to the number of CBGs sent in the PDSCH may have disadvantages in the following two cases.

[0155] i) After the user equipment transmits a PUCCH (or a PUSCH including HARQ-ACK) for sending HARQ-ACK, a NACK-to-ACK error may occur in the base station. In this case, the base station may determine that the CBG to be retransmitted has been successfully sent and may not be sent via the next PDSCH for retransmission. The user equipment expects the retransmission of the CBG that has not been received, but since the CBG is not sent via the next PDSCH, the transmission of a NACK for the retransmission of the corresponding CBG is required. However, since the CBG has not been sent via the next PDSCH for retransmission, the user equipment cannot send a HARQ-ACK for the corresponding CBG. Therefore, when a NACK-to-ACK error that may occur due to the transmission of a PUCCH (or a PUSCH including HARQ-ACK) for sending HARQ-ACK of the user equipment occurs, a method for improving this error is required.

[0156] ii) In CBG-based transmission, the user equipment can determine whether the CBG reception is successful based on the success of the CRC of the CBs included in the CBG. That is, when the CB-CRCs of all the CBs included in the CBG are successfully checked, the user equipment can send an ACK as the HARQ-ACK for the corresponding CBG. On the contrary, when a CB-CRC error occurs in even one of the CBs included in the CBG, the user equipment can send a NACK as the HARQ-ACK for the corresponding CBG. However, whether the TB is successfully received can be determined based on whether the TB-CRC attached to the TB is successfully checked. Therefore, the user equipment can determine that all the CBGs have been successfully received and send an ACK as the HARQ-ACK for the corresponding CBG, but may not be able to check the TB-CRC and thus fails to receive the TB. Therefore, a method for improving this situation is required.

[0157] According to an embodiment of the present invention, a fallback indicator may be used as a method to solve the above problems that may occur when using the method of transmitting HARQ-ACK bits based on the number of CBGs transmitted in the PDSCH. The fallback indicator is an indicator for retransmitting all CBGs of a TB through the PDSCH (hereinafter, referred to as the fallback mode). The user equipment may generate a fallback indicator according to the following embodiments and transmit the fallback indicator together with the HARQ-ACK through the allocated PUCCH resource. The fallback indicator may indicate either of two states. In an embodiment of the present invention, the first state will be referred to as "fallback mode request", and the second state will be referred to as "non-fallback request". "Fallback mode request" is a state for requesting retransmission of all CBGs of a TB, while "non-fallback request" is a state in which retransmission of all CBGs is not required. According to another embodiment of the present invention, the fallback indicator may be used as a TB-based HARQ-ACK. Specific embodiments of the TB-based HARQ-ACK will be described later.

[0158] According to an embodiment of the present invention, in a user equipment configured to operate based on CBGs, only one CBG may be configured for one TB. That is, all CBs included in one TB may be configured as one CBG. In this case, the HARQ-ACK feedback transmitted by the user equipment may be determined based on the success of the TB-CRC. That is, if the TB-CRC check is successful, the user equipment may transmit ACK as the HARQ-ACK for the corresponding CBG. If the TB-CRC check fails, the user equipment may transmit NACK as the HARQ-ACK for the corresponding CBG. In this case, it is possible to determine whether to perform the fallback mode from the ACK / NACK for the CBG without explicitly transmitting a fallback indicator. More specifically, a user equipment expecting to operate in the fallback mode may transmit NACK as the HARQ-ACK for the CBG. When the base station receives NACK as the HARQ-ACK from the user equipment, the base station may determine that the fallback mode is necessary and may retransmit all CBGs of the corresponding TB through the PDSCH.

[0159] According to another embodiment of the present invention, in a user equipment configured to operate based on CBGs, N CBGs (where N is a natural number greater than 1) may be configured for one TB. That is, one TB may be composed of two or more CBGs. In this case, the method for the user equipment to transmit the fallback indicator and the HARQ-ACK is as follows.

[0160] First, N CBGs (i.e., all CBGs) for one TB can be sent in the PDSCH. In this case, the user equipment can determine whether the reception of each CBG is successful through the CB-CRC, and can send HARQ-ACK for the N CBGs through a previously configured or indicated PUCCH resource. When all CB-CRCs included in each CBG are successfully checked, the user equipment can send ACK as the HARQ-ACK for the corresponding CBG. Otherwise, the user equipment can send NACK as the HARQ-ACK for the corresponding CBG. The HARQ-ACK for the CBG can be sent through the HARQ-ACK in the PUCCH or PUSCH sent by the user equipment. The base station can bundle the CBGs for which the user equipment has responded with NACK and retransmit them through the PDSCH. In this case, it can be determined whether to perform the fallback mode from the ACK / NACK for the CBG without an explicit transmission fallback indicator. More specifically, a user equipment expecting to operate in the fallback mode can send NACK as the HARQ-ACK for the CBG. When the base station receives NACK as the HARQ-ACK for all CBGs from the user equipment, it can determine that the fallback mode is necessary and can retransmit all CBGs of the corresponding TB through the PDSCH.

[0161] Table 4 shows the HARQ-ACK feedback that can be sent by the user equipment when N = 2 and its operations. If the HARQ-ACK of the user equipment is [ACK ACK], the base station can determine that the user equipment has successfully received the TB. If the HARQ-ACK of the user equipment is [ACK NACK], the base station can determine that the user equipment has successfully received the first CBG but failed to receive the second CBG. Therefore, the base station can retransmit the second CBG through the PDSCH. If the HARQ-ACK of the user equipment is [NACK ACK], the base station can determine that the user equipment has successfully received the second CBG but failed to receive the first CBG. Therefore, the base station can retransmit the first CBG through the PDSCH. If the HARQ-ACK of the user equipment is [NACK NACK], the base station can determine that the user equipment needs the fallback mode. Therefore, the base station can bundle the first CBG and the second CBG and retransmit them through the PDSCH.

[0162] [Table 4]

[0163] HARQ-ACK feedback Retransmission of CBG [ACK ACK] CBG not retransmitted [ACK NACK] Retransmission of CBG2 [NACK ACK] Retransmission of CBG1 [NACK NACK] Retransmission of CBG1 and CBG (fallback mode)

[0164] Next, for a natural number M less than N, one TB's M CBGs (i.e., some CBGs) can be sent via PDSCH. When sending some CBGs for one TB, the method for the user equipment to send backoff indicators and HARQ-ACKs is as follows. In each embodiment, the same or corresponding parts as in the previous embodiment will be omitted from the repeated description.

[0165] According to a first embodiment of the present invention, the user equipment can send M+1 bits combining the ACK / NACK bits of each of the M CBGs and a 1-bit backoff indicator via HARQ-ACK resources. In this case, the 1-bit backoff indicator can be given priority over the M-bit HARQ-ACK to determine whether to perform the backoff mode. The user equipment can determine whether the reception of each sent CBG is successful via CB-CRC. More specifically, since there is a possibility that up to N CBGs are sent to the user equipment, PUCCH resources capable of accommodating N HARQ-ACK bits are allocated to the user equipment. The user equipment can send 1 to N HARQ-ACK bits via the corresponding resources. The user equipment can send (M+1)-bit feedback by bundling the 1-bit backoff indicator with the M-bit HARQ-ACK in the HARQ-ACK resources. The base station can obtain the M-bit HARQ-ACK and the 1-bit backoff indicator for the sent CBGs by receiving the (M+1)-bit feedback via the PUCCH or PUCCH resources of the PUSCH sent from the user equipment.

[0166] Figure 13 An embodiment of the method for illustrating the received HARQ-ACK feedback and backoff indicator is shown. Refer to Figure 13 , the base station can assign priority to the 1-bit backoff indicator via the M-bit HARQ-ACK to determine whether a backoff mode is required. If a backoff mode is required, the user equipment can send a backoff indicator to indicate "backoff mode request", otherwise, the user equipment can send a backoff indicator to indicate "non-backoff request". The base station checks the status indicated by the received backoff indicator. If the backoff indicator indicates "backoff mode request", the base station can perform the backoff mode while ignoring information such as ACK / NACK / DTX of the M-bit HARQ-ACK. That is, the base station can bundle all the CBGs of the corresponding TB and retransmit them via PDSCH. If the backoff indicator indicates "non-backoff request", the base station can perform CBG retransmission according to the information of the M-bit HARQ-ACK. That is, the base station can bundle the CBGs corresponding to NACK and retransmit them via PDSCH.

[0167] According to the second embodiment of the present invention, the user equipment may use the remaining (N - M) bits out of the N bits ensured by the HARQ-ACK resource as a fallback indicator except for the M HARQ-ACK bits. In this case, the (N - M) - bit fallback indicator can be given priority by the M - bit HARQ-ACK to determine whether to execute the fallback mode. The user equipment may send N bits that combine the ACK / NACK bits for each of the M CBGs and the (N - M) - bit fallback indicator through the HARQ-ACK resource. That is, the user equipment may send N - bit feedback by bundling the (N - M) - bit fallback indicator with the M - bit HARQ-ACK in the HARQ-ACK resource. The base station may obtain the M - bit HARQ-ACK and the (M - N) - bit fallback indicator for the transmitted CBG by receiving the N - bit feedback via the PUCCH or PUSCH sent from the user equipment. The (M - N) - bit fallback indicator may indicate either a "fallback mode request" or a "non - fallback request" state. Since the (M - N) - bit fallback indicator may consist of multiple bits, the transmission reliability may be higher than that of a 1 - bit fallback indicator.

[0168] Reference Figure 13 , the following description explains the method of receiving HARQ-ACK feedback and the fallback indicator. The base station may determine whether a fallback mode is required by assigning priority to the (N - M) - bit fallback indicator through the M - bit HARQ-ACK. If a fallback mode is required, the user equipment may send the (N - M) - bit fallback indicator to indicate a "fallback mode request", otherwise the user equipment may send the (N - M) - bit fallback indicator to indicate a "non - fallback request". The base station checks which state the received fallback indicator indicates. If the fallback indicator indicates a "fallback mode request", the base station may execute the fallback mode. If the fallback indicator indicates a "non - fallback request", the base station may perform CBG retransmission according to the information of the M - bit HARQ-ACK. Its specific implementation example is as described in the first embodiment.

[0169] Table 5 illustrates the fallback indicator and HARQ-ACK feedback that the user equipment may send and their operations when N = 3 and M = 2. In this case, one TB consists of 3 CBGs, and the first CBG and the second CBG, which are some of the CBGs for one TB, may be sent through the PDSCH.

[0170] [Table 5]

[0171]

[0172] Referring to Table 5, the base station can preferably check the fallback indicator through the HARQ-ACK bit. If the fallback indicator indicates "fallback mode request", the base station can always execute the fallback mode. That is, the base station can retransmit all CBGs that make up the TB through the PDSCH, that is, the first CBG, the second CBG, and the third CBG. If the fallback indicator indicates "non-fallback request", the base station can perform CBG retransmission according to the information of the 2-bit HARQ-ACK. That is, if the HARQ-ACK of the user equipment is [ACK ACK], the base station can determine that the user equipment has successfully received two CBGs. If the HARQ-ACK of the user equipment is [ACK NACK], the base station can determine that the user equipment has successfully received the first CBG but has failed to receive the second CBG. Therefore, the base station can retransmit the second CBG through the PDSCH. If the HARQ-ACK of the user equipment is [NACK ACK], the base station can determine that the user equipment has successfully received the second CBG but has failed to receive the first CBG. Therefore, the base station can retransmit the first CBG through the PDSCH. If the HARQ-ACK of the user equipment is [NACK NACK], the base station can determine that the user equipment has failed to receive the first CBG and the second CBG. Therefore, the base station can bundle the first CBG and the second CBG and retransmit them through the PDSCH.

[0173] According to the third embodiment of the present invention, the user equipment can send M + 1 bits that combine the ACK / NACK bits for each of the M CBGs and a 1-bit fallback indicator through the PUCCH resource. In this case, the 1-bit fallback indicator can give priority (or equivalent rank) to the M-bit HARQ-ACK to determine whether to execute the fallback mode. The specific implementation in which the user equipment sends the 1-bit fallback indicator together with the M-bit HARQ-ACK through the HARQ-ACK resource and the base station receives it is as described in the first embodiment.

[0174] Figure 14 Another embodiment of the method for illustrating the received HARQ-ACK feedback and the fallback indicator. Refer to Figure 14, the base station can determine whether a fallback mode is required by assigning a priority (or equivalent rank) to the M-bit HARQ-ACK through a 1-bit fallback indicator. That is, if all of the M-bit HARQ-ACK are NACK, the base station can determine whether a fallback mode is required by checking the 1-bit fallback indicator. If a fallback mode is required, the user equipment can send the M-bit HARQ-ACK to indicate all NACKs and the fallback indicator to indicate a "fallback mode request". In this case, the base station can bundle all CBGs of the corresponding TB and retransmit them through the PDSCH. Otherwise, the base station can determine that a fallback mode is not required. That is, if there is at least one ACK among the M-bit HARQ-ACK, the base station may not perform the fallback mode regardless of the value indicated by the fallback indicator. In this case, the base station can bundle the CBGs corresponding to the NACKs according to the information of the M-bit HARQ-ACK and retransmit them through the PDSCH.

[0175] According to the fourth embodiment of the present invention, the user equipment can use the remaining (N-M) bits among the N bits ensured by the HARQ-ACK resource except for the M HARQ-ACK bits as a fallback indicator. In this case, a priority (or equivalent rank) can be given to the M-bit HARQ-ACK through the (N-M)-bit fallback indicator to determine whether to perform the fallback mode. The specific implementation of the user equipment sending the (N-M)-bit fallback indicator together with the M-bit HARQ-ACK through the HARQ-ACK resource and the base station receiving them is as described above in the second embodiment.

[0176] Reference Figure 14 , the following description explains the method of receiving the HARQ-ACK feedback and the fallback indicator. The base station can determine whether a fallback mode is required by assigning a priority (or equivalent rank) to the M-bit HARQ-ACK through the (N-M)-bit fallback indicator. That is, if all of the M-bit HARQ-ACK are NACK, the base station can determine whether a fallback mode is required by checking the (N-M)-bit fallback indicator. If a fallback mode is required, the user equipment can send the M-bit HARQ-ACK to indicate all NACKs and send the (N-M)-bit fallback indicator to indicate a "fallback mode request". In this case, the base station can bundle all CBGs of the corresponding TB and retransmit them through the PDSCH. Otherwise, the base station can determine that a fallback mode is not required. That is, if there is at least one ACK among the M-bit HARQ-ACK, the base station may not perform the fallback mode regardless of the value indicated by the fallback indicator. In this case, the base station can bundle the CBGs corresponding to the NACKs according to the information of the M-bit HARQ-ACK and retransmit them through the PDSCH.

[0177] Table 6 shows the fallback indicators and HARQ-ACK feedback that a user equipment can send when N = 3 and M = 2, and their operations. In this case, one TB consists of 3 CBGs, and the first CBG and the second CBG among some CBGs for one TB can be sent via PDSCH.

[0178] [Table 6]

[0179]

[0180] Referring to Table 6, if the 2-bit HARQ-ACK is [NACK NACK] and the fallback indicator indicates "fallback mode request", the base station can perform the fallback mode. That is, the base station can retransmit all CBGs that make up the TB via PDSCH, that is, the first CBG, the second CBG, and the third CBG. In all other cases, the base station can determine that the fallback mode is not required. In this case, the base station can perform CBG retransmission according to the information of the 2-bit HARQ-ACK. That is, if the HARQ-ACK of the user equipment is [ACK ACK], the base station can determine that the user equipment has successfully received two CBGs regardless of the value of the fallback indicator. If the HARQ-ACK of the user equipment is [ACK NACK], the base station can determine that the user equipment has successfully received the first CBG but not the second CBG regardless of the value of the fallback indicator. Therefore, the base station can retransmit the second CBG via PDSCH. If the HARQ-ACK of the user equipment is [NACK ACK], the base station can determine that the user equipment has successfully received the second CBG but failed to receive the first CBG regardless of the value of the fallback indicator. Therefore, the base station can retransmit the first CBG via PDSCH. If the HARQ-ACK of the user equipment is [NACK NACK] and the fallback indicator indicates "non-fallback request", the base station can determine that the user equipment has failed to receive the first CBG and the second CBG. Therefore, the base station can bundle the first CBG and the second CBG and retransmit them via PDSCH.

[0181] According to the fifth embodiment of the present invention, the retransmission of the TB can be performed through higher layer retransmission without an explicit fallback indicator. That is, the fallback mode for recovering the erroneous transmission at the physical layer can be not used. According to the embodiment, for the base station and the user equipment, there may be no explicit fallback indicator resource, and there may be only HARQ-ACK resources for CBGs. In this case, if the CBG that needs to be retransmitted to the user equipment is not included in the PDSCH transmission, the user equipment can send ACK as the HARQ-ACK for all CBGs of the PDSCH regardless of the success of the CB-CRC and TB-CRC of the PDSCH transmission. In this way, the user equipment recognizes the reception failure of the corresponding TB, but can prevent unnecessary retransmissions by sending ACK for all CBGs. The TB that fails to be received can be recovered through higher layer retransmission instead of being retransmitted through the HARQ-ACK transmission at the physical layer.

[0182] Figure 15 FIG. illustrates an example of a user equipment sending HARQ-ACK and a fallback indicator according to the above embodiment. According to Figure 15 the embodiment, the base station can configure 3 CBGs in one TB (i.e., N = 3), and thus, PUCCH resources capable of sending 3-bit HARQ-ACK can be allocated to the user equipment. In the first PDSCH transmission, the base station sends CBG#1, CBG#2, and CBG#3. The user equipment successfully receives CBG#3 among the 3 CBGs, but does not receive CBG#1 and CBG#2. Therefore, the user equipment can send [NACK NACK ACK] as the 3-bit HARQ-ACK for the first PDSCH transmission. In the second PDSCH transmission, the base station can retransmit only CBG#1 and CBG#2 in addition to CBG#3 for which ACK has already been received from the user equipment. The user equipment can send 3-bit HARQ-ACK in response to the second PDSCH transmission. In this case, the user equipment can use the first two bits of the 3-bit HARQ-ACK to indicate whether the retransmitted CBG#1 and CBG#2 are received, and use the last bit corresponding to CBG#3 as the fallback indicator.

[0183] Figures 16 to 19 FIG. illustrates an additional embodiment in which the user equipment sends HARQ-ACK feedback and a fallback indicator for CBGs. According to an additional embodiment of the present invention, the length of the HARQ-ACK payload sent by the user equipment can be configured based on the maximum number of CBGs configured by the RRC signal. Therefore, N CBG-based HARQ-ACK bits can be configured for the user equipment. Hereinafter, in Figures 16 to 19In an embodiment, the maximum number of CBGs configured by the RRC signal is N, and the number of CBGs included in the TB transmitted by the base station is M. In this case, M out of the N-bit HARQ-ACK bits may be CBG-based HARQ-ACKs (i.e., M-bit CBG-based HARQ-ACKs) indicating whether the reception of each CBG is successful. Additionally, when M is less than N, the remaining N - M bits out of the N-bit HARQ-ACK may be a fallback indicator.

[0184] In an embodiment of the present invention, the HARQ-ACK indicating whether the user equipment has successfully received each CBG transmitted through the PDSCH is referred to as CBG-based HARQ-ACK or CBG-level HARQ-ACK. Additionally, as described above, in an embodiment of the present invention, the fallback indicator may also be referred to as TB-based HARQ-ACK. In an embodiment of the present invention, the HARQ-ACK indicating whether the user equipment has successfully received each TB transmitted through the PDSCH is referred to as TB-based HARQ-ACK or TB-level HARQ-ACK.

[0185] According to an embodiment of the present invention, the (N - M)-bit fallback indicator may be configured in various ways. According to an embodiment, the (N - M)-bit fallback indicator may be configured as all ACKs or all NACKs. According to another embodiment, the (N - M)-bit fallback indicator may be configured by repeating the 1-bit TB-based HARQ-ACK with N - M bits. According to still another embodiment, the (N - M)-bit fallback indicator may be configured based on the value of the M-bit CBG-based HARQ-ACK. If M is an integer divisor of N, the (N - M)-bit fallback indicator may be configured by repeating the value of the M-bit CBG-based HARQ-ACK.

[0186] Table 7 shows an embodiment of configuring 4-bit HARQ-ACK feedback when N = 4 and M = 1 to 4. First, when M = 1, 4-bit HARQ-ACK [b0 b0 b0 b0] can be configured by repeating the HARQ-ACK b0 for CBG#0 four times. Next, when M = 2, 4-bit HARQ-ACK [b0 b1 b0 b1] can be configured by repeating the HARQ-ACK b0 for CBG#0 and the HARQ-ACK b1 for CBG#1 twice. Next, when M = 3, 4-bit HARQ-ACK [b0 b1 b2 x] can be configured by using the HARQ-ACK b0 for CBG#0, the HARQ-ACK b1 for CBG#1, the HARQ-ACK b2 for CBG#2, and x determined by the combination of b0, b1, and b2. According to an embodiment, x can be obtained by the exclusive OR operation of b0, b1, and b2. According to another embodiment, x can be determined by the value of b0 + b1 + b2 (mod 2). Table 7 shows an embodiment of configuring N-bit HARQ-ACK feedback, and the N-bit HARQ-ACK feedback can be configured by a combination of at least one of the above embodiments.

[0187] [Table 7]

[0188]

[0189] According to yet another embodiment of the present invention, a user equipment can be configured in a transmission mode in which two TBs can be transmitted in one PDSCH. In this case, the user equipment can send HARQ-ACK feedback according to the length of the CBG-based HARQ-ACK payload for the two TBs. If each TB is configured with the maximum number of CBGs and the user equipment receives a PDSCH that schedules only one TB, the user equipment can generate a HARQ-ACK having the length of the CBG-based HARQ-ACK payload for the two TBs by repeating the CBG-based HARQ-ACK for one TB.

[0190] For example, the user equipment may be configured with a transmission mode in which up to two transport blocks (TBs) can be transmitted and one TB can include up to 4 codeblock groups (CBGs). If only one TB is scheduled for the user equipment, an 8-bit hybrid automatic repeat request acknowledgement (HARQ-ACK) [b0 b1 b2 b3 b0 b1 b2 b3] can be configured by repeating twice the CBG-based HARQ-ACK [b0 b1 b2 b3] for the 4 CBGs included in the TB. On the other hand, if two TBs are scheduled to the user equipment, an 8-bit HARQ-ACK [b0 b1 b2 b3 c0 c1 c2 c3] can be configured by combining the HARQ-ACK [b0 b1 b2 b3] for the 4 CBGs included in the first TB and the HARQ-ACK [c0 c1 c2 c3] for the 4 CBGs included in the second TB. The user equipment may send the configured HARQ-ACK to the base station.

[0191] Meanwhile, even in the transmission mode where two TBs can be transmitted in one physical downlink shared channel (PDSCH), the number M of CBGs included in the TBs sent by the base station may be less than N. In this case, a method of configuring the remaining N - M bits out of the N-bit HARQ-ACK is the same as that in the above embodiment.

[0192] Meanwhile, according to an additional embodiment of the present invention, the CBG-based HARQ-ACK and the fallback indicator (or TB-based HARQ-ACK) resources for the CBGs can be transmitted through different physical uplink control channels (PUCCHs). Figures 16 to 19 Illustrates an embodiment in which the user equipment transmits the CBG-based HARQ-ACK and the fallback indicator through different HARQ-ACK resources.

[0193] First, Figure 16 Illustrates an embodiment in which different HARQ-ACK resources are allocated to the transmission of the CBG-based HARQ-ACK and the transmission of the fallback indicator (or TB-based HARQ-ACK). Refer to Figure 16, the base station may allocate two HARQ-ACK resources to the user equipment at different times. The two different HARQ-ACK resources may be respectively used for the transmission of CBG-based HARQ-ACK and the fallback indicator (or TB-based HARQ-ACK). According to an embodiment of the present invention, the resource for transmitting the fallback indicator (or TB-based HARQ-ACK) may be configured to be before the resource for transmitting the CBG-based HARQ-ACK. For example, the user equipment may be allocated time slot n + k1 (i.e., resource A) and time slot n + k2 (i.e., resource B) as the HARQ-ACK resources for the PDSCH received in time slot n (where k1 < k2). Among the above resources, the resource A in time slot n + k1 may be the resource for transmitting the fallback indicator (or TB-based HARQ-ACK), and the resource B in time slot n + k2 may be the resource for transmitting the CBG-based HARQ-ACK. At the same time, the length of the CBG-based HARQ-ACK payload transmitted through resource B may be configured based on any one of the number of CBGs transmitted, the maximum number of CBGs configured by the RRC signal, or the number of CBGs that may be included in the corresponding TB.

[0194] Figure 17 FIG. illustrates an embodiment of transmitting CBG-based HARQ-ACK and the fallback indicator (or TB-based HARQ-ACK) through different HARQ-ACK resources. According to Figure 17 the embodiment, the user equipment may selectively transmit only one of the CBG-based HARQ-ACK and the TB-based HARQ-ACK. More specifically, if all the HARQ-ACKs for the CBGs are ACK or all are NACK when the user equipment configured for CBG-based communication sends HARQ-ACK to the base station, the user equipment may transmit only the TB-based HARQ-ACK and may not transmit the CBG-based HARQ-ACK. On the other hand, if the HARQ-ACKs for the CBGs include at least one ACK and at least one NACK, the user equipment may transmit only the CBG-based HARQ-ACK and may not transmit the TB-based HARQ-ACK.

[0195] The user equipment may select one of the two different HARQ-ACK resources according to the type of HARQ-ACK to be transmitted among the CBG-based HARQ-ACKs and the fallback indicator (i.e., the TB-based HARQ-ACK), and transmit the corresponding HARQ-ACK through the selected resource. As Figure 17As shown in (a), when transmitting a TB-based HARQ-ACK, the user equipment may transmit the TB-based HARQ-ACK through time slot n + k1. In this case, the user equipment may not transmit the CBG-based HARQ-ACK through time slot n + k2. According to an embodiment, when the TB-CRC is successfully checked, the user equipment may transmit an ACK as the TB-based HARQ-ACK. Meanwhile, when all CB-CRCs have been successfully checked but a TB-CRC error occurs, the user equipment may transmit a NACK as the TB-based HARQ-ACK. Additionally, even when the reception of all CBGs fails (i.e., when all CB-CRCs have failed), the user equipment may transmit a NACK as the TB-based HARQ-ACK. As Figure 17 As shown in (b), when transmitting a CBG-based HARQ-ACK, the user equipment may transmit the CBG-based HARQ-ACK through time slot n + k2. In this case, the user equipment may not transmit the TB-based HARQ-ACK through time slot n + k1.

[0196] In Figure 17 the embodiment of, the operation of the base station is as follows. The base station may expect the user equipment to transmit a TB-based HARQ-ACK through resource A in time slot n + k1. If the base station successfully receives the TB-based HARQ-ACK from the user equipment through resource A and the HARQ-ACK is ACK, the base station determines that the user equipment has successfully received the TB. If the base station successfully receives the TB-based HARQ-ACK from the user equipment through resource A and the HARQ-ACK is NACK, the base station determines that the user equipment has not received all CBGs (or all CBs). Accordingly, the base station may retransmit all CBGs (or all CBs). When the base station successfully receives the TB-based HARQ-ACK from the user equipment through resource A, the base station may determine that the user equipment has not used resource B (i.e., time slot n + k2). Thus, when transmitting the TB-based HARQ-ACK of the user equipment through resource A, resource B may be used for other purposes. For example, resource B may be used for the HARQ-ACK transmission of another user. On the other hand, if the base station does not successfully receive the TB-based HARQ-ACK from the user equipment through resource A, the base station may determine that the user equipment has transmitted a CBG-based HARQ-ACK. Accordingly, the base station may receive the CBG-based HARQ-ACK of the user equipment through resource B in time slot n + k2. The base station may perform retransmission of the CBGs that the user equipment has not received based on the CBG-based HARQ-ACK.

[0197] Figure 18Another embodiment of transmitting CBG-based HARQ-ACK and fallback indicators (or TB-based HARQ-ACK) via different HARQ-ACK resources is illustrated. According to Figure 18 the embodiment, the user equipment may transmit only the TB-based HARQ-ACK or both the CBG-based HARQ-ACK and the TB-based HARQ-ACK according to whether all CBGs are successfully received.

[0198] As Figure 18 (a) shows, when the user equipment successfully receives all CBGs and successfully checks the TB-CRC, the user equipment may transmit an ACK as the TB-based HARQ-ACK via slot n + k1. In this case, the user equipment may not transmit the CBG-based HARQ-ACK via slot n + k2. However, as Figure 18 (b) shows, when the user equipment fails to receive at least one CBG or a TB-CRC error occurs, the user equipment may transmit a NACK as the TB-based HARQ-ACK via slot n + k1. In this case, the user equipment may transmit the CBG-based HARQ-ACK via slot n + k2.

[0199] In Figure 18 the embodiment, the operation of the base station is as follows. The base station always expects the user equipment to perform TB-based HARQ-ACK transmission via resource A in slot n + k1. If the TB-based HARQ-ACK of the user equipment received via resource A is ACK, the base station determines that the user equipment has successfully received the TB. In this case, the base station may determine that the user equipment does not use resource B (i.e., slot n + k2). Therefore, when transmitting the user equipment's TB-based HARQ-ACK via resource A, resource B may be used for other purposes. For example, resource B may be used for HARQ-ACK transmission of another user. If the TB-based HARQ-ACK of the user equipment is successfully received via resource A and the HARQ-ACK is NACK (or DTX), the base station determines that the user equipment fails to receive at least one CBG. In this case, the base station receives the CBG-based HARQ-ACK of the user equipment via resource B. The base station may perform retransmission of the CBGs that the user equipment fails to receive based on the CBG-based HARQ-ACK.

[0200] According to another embodiment of the present invention, even when the TB-based HARQ-ACK is ACK, the TB-based HARQ-ACK and the CBG-based HARQ-ACK of the user equipment can be sent together. The base station can receive the TB-based HARQ-ACK and the CBG-based HARQ-ACK through resource A and resource B respectively, and determine the reception success of the user equipment by using the received HARQ-ACK. For example, if the TB-based HARQ-ACK is ACK and all the CBG-based HARQ ACKs are ACK, the base station determines that the user equipment has successfully received the TB. However, if the TB-based HARQ-ACK is ACK and not all the CBG-based HARQ ACKs are ACK, the base station performs CBG-based retransmission based on the CBG-based HARQ-ACK. As another method, if the TB-based HARQ-ACK is ACK, the base station can determine that the user equipment has successfully received the TB regardless of the value of the CBG-based HARQ-ACK.

[0201] If the CBG-based HARQ-ACK is not successfully received through resource B even when the TB-based HARQ-ACK is NACK, the base station can determine that the user equipment has not received all the CBGs and can retransmit all the CBGs. According to another embodiment, if the CBG-based HARQ-ACK is not successfully received through resource B even when the TB-based HARQ-ACK is NACK, the base station can consider that an ACK-to-NACK error has occurred in the TB-based HARQ-ACK and can determine that the user equipment has successfully received the TB.

[0202] In addition, if the TB-based HARQ-ACK is NACK and all the CBG-based HARQ-ACKs are ACK, the base station can retransmit all the CBGs on the assumption that the user equipment has not received all the CBGs. According to another embodiment, if the TB-based HARQ-ACK is NACK and all the CBG-based HARQ-ACKs are ACK, the base station can consider that an ACK-to-NACK error has occurred in the TB-based HACQ-ACK and can determine that the user equipment has successfully received the TB.

[0203] Figure 19FIG. illustrates an embodiment in which a user equipment receives a PDCCH scheduling a retransmission of a corresponding transport block (TB) between a transmission of TB-based HARQ-ACK and a transmission of CBG-based HARQ-ACK. More specifically, when the user equipment transmits a TB-based HARQ-ACK through resource A in slot n + k1 and transmits a CBG-based HARQ-ACK through resource B in slot n + k2, the user equipment may receive, in slot n + k3 before slot n + k2, a PDCCH scheduling a retransmission of the corresponding TB (i.e., k3 < k2). In this case, the user equipment may not transmit a CBG-based HARQ-ACK through slot n + k2. Thus, when the base station transmits a PDCCH scheduling a retransmission of a TB before slot n + k2 used for transmitting a CBG-based HARQ-ACK, resource B in slot n + k2 may be used for other purposes. For example, resource B may be used for HARQ-ACK transmission of another user.

[0204] According to an embodiment of the present invention, the base station may indicate information about resource A in slot n + k1 and resource B in slot n + k2 to the user equipment in various ways. According to an embodiment, the base station may independently indicate offsets k1 and k2 through DCI. According to another embodiment, the base station may notify or fix the difference between offsets k1 and k2 to the user equipment in advance and indicate only one of offsets k1 or k2 through DCI. The user equipment may obtain the values of offsets k1 and k2 by using any one of the offsets indicated by DCI and the previously known (or fixed) offset difference. In this case, the smaller value of the obtained offsets may be used as the offset for transmitting a TB-based HARQ-ACK, and the larger value of the offsets may be used as the offset for transmitting a CBG-based HARQ-ACK.

[0205] If HARQ-ACK multiplexing is configured for the user equipment, the TB-based HARQ-ACK transmitted through resource A in slot n + k1 in the above embodiment may be multiplexed with TB-based HARQ-ACKs for one or more transport blocks. Additionally, the CBG-based HARQ-ACK transmitted through resource B in slot n + k2 in the above embodiment may be multiplexed with CBG-based HARQ-ACKs for one or more transport blocks. According to an embodiment, the CBG-based HARQ-ACK transmitted through resource B may be generated by multiplexing CBG-based HARQ-ACK bits for a transport block for which a NACK is transmitted as a TB-based HARQ-ACK. That is, for a transport block for which an ACK is transmitted as a TB-based HARQ-ACK through resource A, no CBG-based HARQ-ACK transmission is performed through resource B.

[0206] Meanwhile, in the above embodiments, resources have been described based on time slots, but the present invention is not limited thereto. That is, in the case of short PUCCH transmissions, for example, the time slots of the above embodiments may be replaced by OFDM symbols. In this case, OFDM symbol n + k1 and / or ODFM symbol n + k2 may be the OFDM symbol at which PUCCH starts.

[0207] In addition, in the above embodiments, it is assumed that k1 < k2. However, according to another embodiment of the present invention, the offsets k1 and k2 may be set to the same value (i.e., k = k1 = k2). That is, HARQ-ACK resources of the same time may be allocated for the transmission of TB-based HARQ-ACK and CBG-based HARQ-ACK. When the user equipment is configured with a transmission mode in which two TBs can be transmitted in one PDSCH, the user equipment may perform HARQ-ACK transmission by selecting one of resource A and resource B configured in the same time slot n + k. According to an embodiment, if the HARQ-ACKs for two TBs transmitted through one PDSCH are both ACK, the user equipment may send [ACK ACK] as the TB-based HARQ-ACK through resource A of time slot n + k. In this case, the user equipment may not use resource B of time slot n + k. If the HARQ-ACKs for two TBs transmitted through one PDSCH are not all ACK, the user equipment may send the CBG-based HARQ-ACK for the CBG included in the two TBs through resource B of time slot n + k. In this case, the user equipment may not use resource A of time slot n + k.

[0208] According to still another embodiment of the present invention, when CBG-based HARQ-ACKs for multiple TBs are multiplexed, compressed CBG-based HARQ-ACKs may be used to reduce the payload length. That is, compressed CBG-based HARQ-ACKs may be used by reducing the length of the payload in the original CBG-based HARQ-ACK. The user equipment generates compressed CBG-based HARQ-ACKs from the original CBG-based HARQ-ACKs according to a predetermined rule, and sends the compressed CBG-based HARQ-ACKs to the base station.

[0209] A first embodiment of generating compressed CBG-based HARQ-ACK is as follows. The base station may select, among the entire CBG-based HARQ-ACK states for one TB, the states that are expected to occur frequently, such that the user equipment can signal such states. Herein, the CBG-based HARQ-ACK state refers to a combination of bits that the original CBG-based HARQ-ACK may have. That is, a 4-bit CBG-based HARQ-ACK can have a total of 16 states, i.e., states from [ACK ACK ACK ACK] to [NACK NACK NACK NACK]. The base station may select P states among the original CBG-based HARQ-ACK states as described above. That is, when the total number of TBs transmitted via PDSCH is I, the original CBG-based HARQ-ACK state of the i-th TB can be mapped to the p i -th state among the P states. In this case, the user equipment multiplies the mapped p for a total of I TBs by the following equation i to obtain U, and converts U into a binary value to obtain the compressed CBG-based HARQ-ACK for the entire TB.

[0210]

[0211] The base station receives the compressed CBG-based HARQ-ACK from the user equipment, and converts the compressed CBG-based HARQ-ACK into a P-symbol value to obtain the mapped CBG-based HARQ-ACK state information p for each TB i .

[0212] According to an embodiment, the value of P selected by the base station and the information of the P CBG-based HARQ-ACK states may be configured by an RRC signal sent from the base station to the user equipment. According to another embodiment, the value of P may be determined based on at least one of the capacity of the PUCCH that the user equipment can transmit and the number of TBs (or the number of PDSCHs) that the user equipment is to transmit. Additionally, in order to determine the P CBG-based HARQ-ACK states, the entire CBG-based HARQ-ACK states may be arranged in a preset order. According to an embodiment, the preset order may be determined based on the occurrence frequency of each state in the entire CBG-based HARQ-ACK states. For example, the CBG-based HARQ-ACK states indicating reception errors of adjacent CBGs may be determined in a higher order than the CBG-based HARQ-ACK states indicating reception errors of non-adjacent CBGs. P states may be selected from the entire CBG-based HARQ-ACK states based on the preset order.

[0213] Table 8 shows an embodiment of determining P CBG-based HARQ-ACK states. In the embodiment of Table 8, P states are determined from a total of 16 original CBG-based HARQ-ACK states based on 4 CBG-based HARQ-ACK bits. Here, information of P CBG-based HARQ-ACK states selected when P is 2, 4, 6, 9, 11, 14, or 16 is illustrated.

[0214] [Table 8]

[0215]

[0216] Each of the selected P states may be indexed as the pth state based on a preset order. i As described above, the original CBG-based HARQ-ACK state of each TB can be mapped to the pth state among the P states. i When the number of original CBG-based HARQ-ACK states is N, mapping from N to P may be performed. According to an embodiment of the present invention, the original CBG-based HARQ-ACK state may be mapped to the pth state based on the NACK bit of the original state. i That is, even in the pth state of the mapping i In the CBG-based HARQ-ACK state, the bit that is NACK in the original CBG-based HARQ-ACK state will be NACK. For example, when the second bit is NACK (i.e., 0) in the original CBG-based HARQ-ACK state, the state to which the original state can be mapped can be one of the states where the second bit is NACK (i.e.,

[0000] ,

[0001] ,

[0010] ,

[0011] ,

[1000] ,

[1001] ,

[1010] , and

[1011] ).

[0217] A second embodiment of generating a compressed CBG-based HARQ-ACK is as follows. The maximum number of CBGs configured by the RRC signal is N, and the number of CBGs included in the TB sent by the base station is M. In this case, the M bits among the N-bit HARQ-ACK may be a CBG-based HARQ-ACK indicating whether the reception of each CBG is successful (i.e., an M-bit CBG-based HARQ-ACK). The base station may configure the length of the original CBG-based HARQ-ACK payload for one TB based on the maximum number of CBGs configured by the RRC signal. That is, the original CBG-based HARQ-ACK for one TB may consist of N bits. In this case, the original CBG-based HARQ-ACK may consist of [b0, b1, ..., b M-1 ,X0,X1,...,XN-M-1 is represented. That is, the original CBG-based HARQ-ACK can be composed of an M-bit CBG-based HARQ-ACK [b0, b1,..., b M-1 and the remaining N - M bits [X0, X1,..., X N-M-1 . In this case, X m can be configured with a fixed value (e.g., ACK or NACK), or can be configured based on the value of the M-bit CBG-based HARQ-ACK. The specific method is the same as that in the above embodiments.

[0218] To reduce the length of the HARQ-ACK payload, the base station can instruct the user equipment to use a compressed CBG-based HARQ-ACK. The base station can signal the indication information through an RRC signal or PDCCH. When the user equipment receives the information indicating the use of the compressed CBG-based HARQ-ACK, the user equipment can reduce the original CBG-based HARQ-ACK composed of N bits into a compressed CBG-based HARQ-ACK composed of L bits.

[0219] If L is greater than or equal to M, the compressed CBG-based HARQ-ACK can be composed of [b0, b1,..., b M-1 , Y0, Y1,..., Y L-M-1 . That is, the compressed CBG-based HARQ-ACK can be composed of an M-bit CBG-based HARQ-ACK [b0, b1,..., b M-1 and the remaining L - M bits [Y1,..., Y L-M-1 . Therefore, the M-bit CBG-based HARQ-ACK is included in the compressed CBG-based HARQ-ACK as it is, and only the remaining bits are reduced from N - M to L - M. That is, the M-bit CBG-based HARQ-ACK can be retained in the compressed CBG-based HARQ-ACK. In this case, Y m can be configured with a fixed value (e.g., ACK or NACK), or can be configured based on the value of the M-bit CBG-based HARQ-ACK.

[0220] If L is less than M, the compressed CBG-based HARQ-ACK can be composed of [a0, a1,..., a M-1 . In this case, by combining the M-bit CBG-based HARQ-ACK [b0, b1,..., b in the original CBG-based HARQ-ACK except for the remaining N - M bits M-1at least a part of to generate a compressed CBG-based HARQ-ACK. According to an embodiment, in the compressed CBG-based HARQ-ACK [a0, a1,..., a M-1 , when b k*w , b k*w+1 ,..., b (k+1)*w-1 are all 1 (i.e., ACK), a k for k = 0 to L - 2 is 1 (i.e., ACK). Moreover, when b k*w , b k*w+1 ,..., b M-1 are all 1 (i.e., ACK), a k for k = L - 1 is 1 (i.e., ACK). Otherwise it is 0 (i.e., NACK). Here, w = floor(M / L).

[0221] For example, it can be assumed that N = 8 and M = 4, and the remaining N - M bits (i.e., 4 bits) always send 0 (i.e., NACK). Additionally, it can be assumed that the original CBG-based HARQ-ACK is [10110000]. When generating a 4-bit compressed CBG-based HARQ-ACK from the original CBG-based HARQ-ACK, the compressed CBG-based HARQ-ACK becomes

[1011] . That is, even if the payload length is reduced to 4 bits, the 4-bit CBG-based HARQ-ACK

[1011] can be retained in the compressed CBG-based HARQ-ACK. On the other hand, when generating a 2-bit compressed CBG-based HARQ-ACK from the original CBG-based HARQ-ACK, the compressed CBG-based HARQ-ACK becomes

[01] . In this case, the 4-bit CBG-based HARQ-ACK

[1011] is not retained in the compressed CBG-based HARQ-ACK. The compressed CBG-based HARQ-ACK

[01] can be generated by bundling the 4-bit CBG-based HARQ-ACK

[1011] using 2 bits.

[0222] In the following embodiments, the transmission scenario is assumed on a per-component-carrier basis. In the embodiments of the present invention, a component carrier may be replaced by the term cell. In the embodiments of the present invention, for ease of description, the transmission using carrier aggregation is described. However, in a TDD system using carrier aggregation, a component carrier may refer to all component carriers of a subframe (or time slot) in which HARQ-ACK is multiplexed. A user equipment may receive PDSCH in one or more component carriers and generate a HARQ-ACK bit sequence in response thereto. The HARQ-ACK bit sequence may be generated by combining HARQ-ACK bits for each of the one or more component carriers. In the embodiments of the present invention, terms such as HARQ-ACK information bits, HARQ-ACK codebooks, HARQ-ACK codewords, HARQ-ACK payloads, etc. may be used instead of the HARQ-ACK bit sequence. In the following embodiments, the HARQ-ACK bit sequence for the TB-based transmission (or PDSCH) may be referred to as the TB-based HARQ-ACK bit sequence, and the HARQ-ACK bit sequence for the CBG-based transmission (or PDSCH) may be referred to as the CBG-based HARQ-ACK bit sequence.

[0223] When using carrier aggregation, each component carrier may be configured with a different transmission scheme. That is, the transmission of one TB may be configured in the first component carrier, and the transmission of two TBs may be configured in the second component carrier. Additionally, in the 3GPP NR system, in addition to the TB-based transmission as described above, CBG-based transmission is also supported. Therefore, the TB-based transmission may be configured in the first component carrier, and the CBG-based transmission may be configured in the second component carrier.

[0224] Meanwhile, the user equipment monitors the PDCCH in a specific component carrier according to the configured scheme for the user equipment in its own carrier scheduling and cross-carrier scheduling, and receives the PDSCH based on the information of the PDCCH. In addition, the user equipment sends HARQ-ACK for the TB sent through the PDSCH on each component carrier through the PUCCH (or PUSCH). However, the user equipment may not be able to decode the PDCCH scheduled by some of the component carriers configured by the base station (i.e., DTX occurs). In this case, excluding the HARQ-ACK of the corresponding component carrier, the user equipment can send only the HARQ-ACK of the successfully decoded component carriers through the PUCCH (or PUSCH). However, when the user equipment excludes the transmission of HARQ-ACK for some component carriers, an error may occur in the HARQ-ACK feedback interpretation between the base station and the user equipment. To solve this problem, a method using a downlink allocation index (DAI) to detect DTX is used in LTE-A Release 13.

[0225] Figure 20 An example of the value of the downlink allocation index (DAI) mapped to each component carrier is shown. Refer to Figure 20 , the PDCCH scheduling each PDSCH includes a counter-DAI and a total-DAI. The counter-DAI represents the cumulative number of PDSCHs scheduled from the first component carrier (i.e., component carrier #0) to the current component carrier. In addition, the total-DAI represents the total number of PDSCHs scheduled for the entire component carrier. If the counter-DAI field consists of A bits, the value of the counter-DAI is between 0 and 2 A *n - 1 (where n is a natural number). If the number of PDSCHs scheduled from the first component carrier to the current component carrier is C, the value of the counter-DAI can be set to (C - 1) mod 2 A . Similarly, if the total-DAI field consists of B bits, the value of the total-DAI is between 0 and 2 B *m - 1 (where m is a natural number). If the total number of PDSCHs scheduled for the entire component carrier is T, the value of the total-DAI can be set to (T - 1) mod 2 B . The user equipment can identify the order in which the PDSCHs are sent by decoding the PDCCH. In this case, the user equipment can send the HARQ-ACK of the PDSCH in the order in which the corresponding PDSCH is sent.

[0226] Refer to Figure 20, the base station can send PDSCH to a user equipment that can use up to 8 component carriers through component carriers #0, #1, #3, #4, #5, and #7. Since the total number of PDSCHs scheduled for component carriers is 6, the total-DAI value is set to 5. Therefore, the (counter-DAI, total-DAI) values of component carriers #0, #1, #3, #4, #5, and #7 are (0, 5), (1, 5), (2, 5), (3, 5), (4, 5), (5, 5), respectively. When the decoding of the PDCCH sent on component carrier #3 fails, the user equipment can identify the reception failure of a PDCCH (and the corresponding reception of a PDSCH) based on the counter-DAI value of the PDCCH sent on component carrier #1 and the counter-DAI value of the PDCCH sent on component carrier #4. Additionally, when the decoding of the PDCCH sent on component carrier #7 fails, the user equipment can identify the unsuccessful reception of a PDSCH scheduled after component carrier #5 based on the counter-DAI value of the PDCCH sent on component carrier #5 and the total-DAI value.

[0227] By using DAI as described above, the user equipment can identify the order of PDSCHs that have been successfully received and the order of PDSCHs that have not been received. However, the user equipment cannot identify the number of TBs included in the PDSCHs that have not been received and thus cannot determine the HARQ-ACK bit sequence. To solve this problem, two methods can be used. The first method is to apply spatial bundling to all PDSCHs. In other words, the 2-bit HARQ-ACK for a PDSCH that sends two TBs can be bundled to generate 1 bit. This method has no additional UCI overhead, but may reduce the transmission performance. The second method does not apply spatial bundling, but assumes that all PDSCHs contain two TBs. In other words, in this method, even for a PDSCH that sends 1 TB, 2-bit HARQ-ACK is sent. This method has the disadvantage of generating additional UCI overhead.

[0228] Meanwhile, as described above, in the 3GPP NR system, both TB-based transmission and CBG-based transmission are supported together. When a user equipment is configured to multiplex and transmit HARQ-ACK bits for multiple component carriers, the base station may notify the user equipment whether CBG-based transmission is possible for each component carrier. However, in a component carrier configured for CBG-based transmission, TB-based transmission may also be performed. Therefore, the user equipment may expect TB-based transmission only on a specific component carrier, and may expect both TB-based transmission and CBG-based transmission on another specific component carrier. The user equipment can determine the HARQ-ACK bit sequence to be transmitted on the uplink only after successfully receiving all the PDCCHs scheduled for each component carrier.

[0229] To prevent errors in determining and interpreting the HARQ-ACK bit sequence between the base station and the user equipment, the above DAI can be used according to an embodiment of the present invention. Assuming that N HARQ-ACK bits are required in response to CBG-based transmission, the user equipment and the base station can use the following three methods to prevent misinterpretation of the HARQ-ACK bit sequence that may occur when decoding of the CBG fails.

[0230] According to the first method, when the base station configures CBG-based transmission to the user equipment in at least one component carrier using carrier aggregation, it can be assumed that CBG-based transmission is performed for all the PDSCHs scheduled for the user equipment. That is, even when the base station performs TB-based transmission to the user equipment in a specific component carrier, the user equipment can feedback N-bit HARQ-ACK. Here, N can be the maximum number of CBGs for each TB configured for the user equipment. However, in the case of the first method, there is a disadvantage that the overhead of the PUCCH is too large. For example, if N = 4, the HARQ-ACK of 1 bit is increased to 4 bits, resulting in a possible overhead of up to 300%.

[0231] According to the second method, when the base station configures CBG-based transmission to the user equipment in at least one component carrier using carrier aggregation, it can be assumed that TB-based transmission is performed for all the PDSCHs scheduled for the user equipment. In this case, the user equipment can be fixed to feedback 1-bit or 2-bit HARQ-ACK in response to the PDSCH. However, in the second method, even if the user equipment is configured for CBG-based transmission from the base station and actually performs CBG-based transmission, the HARQ-ACK feedback information based on CBG-based transmission cannot be used, so the performance gain of CBG-based transmission cannot be obtained.

[0232] According to the third method, when the base station configures whether to perform CBG-based transmission to the user equipment for each component carrier during carrier aggregation, it can be assumed that CBG-based transmission or TB-based transmission is performed in the PDSCH scheduled for the user equipment according to whether CBG-based transmission is configured for the corresponding component carrier and the DCI scheduling the PDSCH. That is, when the base station configures CBG-based transmission to the user equipment in a specific component carrier, even if the base station performs TB-based transmission to the user equipment in the specific component carrier, the user equipment can feedback N-bit HARQ-ACK. Here, N can be the maximum number of CBGs for each TB configured for the user equipment. If the base station does not configure CBG-based transmission to the user equipment in a specific component carrier, the user equipment can be fixed to feedback 1-bit or 2-bit HARQ-ACK by assuming that TB-based transmission is performed on the PDSCH scheduled for the specific component carrier.

[0233] As described above, when both TB-based transmission and CBG-based transmission are configured for the user equipment using HARQ-ACK multiplexing, a signaling scheme for preventing misinterpretation of the HARQ-ACK bit sequence between the base station and the user equipment can be provided. According to an embodiment of the present invention, the user equipment can receive a PDCCH indicating PDSCH scheduling information for each component carrier in one or more component carriers. In addition, the user equipment can receive DCI through the PDCCH. In this case, CBG-based transmission can be configured in at least one of the one or more component carriers. In addition, at least one TB-based transmission and at least one CBG-based transmission can be configured in the one or more component carriers. The user equipment can identify the transmission scheme in each component carrier based on the DCI format of the DCI. In this case, the transmission scheme is TB-based transmission or CBG-based transmission. At the same time, the user equipment can receive DAI through the PDCCH. The DAI includes the counter-DAI and the total-DAI as described above.

[0234] The user equipment receives the PDSCH of each component carrier in one or more component carriers based on the scheduling information of the PDCCH, and generates a HARQ-ACK bit sequence in response to receiving the PDSCH of each component carrier. In this case, the user equipment generates the HARQ-ACK bit sequence with reference to the DAI. The HARQ-ACK bit sequence includes at least one of a HARQ-ACK bit sequence for TB-based transmission (i.e., a TB-based HARQ-ACK bit sequence) and a HARQ-ACK bit sequence for CBG-based transmission (i.e., a CBG-based HARQ-ACK bit sequence). According to an embodiment of the present invention, the DAI can be applied to the TB-based HARQ-ACK bit sequence and the CBG-based HARQ-ACK bit sequence respectively. In addition, within the HARQ-ACK bit sequence, the TB-based HARQ-ACK bit sequence can be before the CBG-based HARQ-ACK bit sequence.

[0235] The user equipment can generate a HARQ-ACK bit sequence for one or more cells based on the identified transmission scheme of each cell. That is, a TB-based HARQ-ACK bit sequence and a CBG-based HARQ-ACK bit sequence can be generated separately in the HARQ-ACK bit sequence. In this case, one HARQ-ACK bit is generated for each TB in the TB-based HARQ-ACK bit sequence, and N HARQ-ACK bits are generated for each TB in the CBG-based HARQ-ACK bit sequence. That is, the HARQ-ACK bits for the CBG-based PDSCH are configured to have N bits equally for each TB, regardless of the number of CBGs actually scheduled and transmitted in the PDSCH.

[0236] According to an embodiment of the present invention, N can be the maximum number of CBGs for each TB configured for the user equipment. According to another embodiment, N can be a value configured by the base station for HARQ-ACK multiplexing. According to another embodiment, if the number M of CBGs transmitted through a specific component carrier configured for CBG-based transmission in one or more component carriers is less than N, the HARQ-ACK bits for the specific component carrier can be configured by repeating the HARQ-ACK bits for the transmitted CBGs. In addition, if the number M of CBGs transmitted through a specific component carrier configured for CBG-based transmission in one or more component carriers is less than N, the HARQ-ACK bits for the specific component carrier can be composed of M HARQ-ACK bits for the transmitted CBGs and N - M ACKs. The user equipment sends the HARQ-ACK bit sequence generated in this way to the base station.

[0237] When a user equipment receives a PDCCH, the user equipment can identify whether a TB-based transmission or a CBG-based transmission is applied to the PDSCH scheduled by the PDCCH. The user equipment can identify the transmission scheme in each component carrier (i.e., PDSCH) based on the information of the DCI received through the PDCCH. For example, the transmission scheme information can be signaled by an explicit 1-bit in the DCI, or can be inferred from the combination of other information included in the DCI. Additionally, the transmission scheme in each component carrier can be identified based on the DCI format of the DCI. Different DCI formats can be used for different transmission schemes. Different DCI formats may have different sizes of information included in the DCI. That is, different DCI formats can have different DCI payload lengths. Additionally, the CRC can be scrambled with different RNTIs in different DCI formats. Additionally, when receiving a PDCCH for scheduling a CBG-based PDSCH, the user equipment can identify which CBGs in the whole CBG are included in the PDSCH through the information specified in the DCI.

[0238] In the following, specific embodiments of generating a HARQ-ACK bit sequence in response to receiving a PDSCH will be described with reference to each drawing. In each embodiment, it is assumed that CBG-based transmission is configured in at least one component carrier (i.e., cell) among one or more component carriers. For example, at least one TB-based transmission and at least one CBG-based transmission can be configured in one or more component carriers. Additionally, in the embodiments of each drawing, parts that are the same as or corresponding to the previous drawings will be omitted. In the embodiments of the present invention, for ease of description, it is assumed that the value of each index or counter starts from 0 and increases by 1. However, the embodiments of the present invention are not limited thereto, and the index or counter value can start from a predetermined value (e.g., 1) and increase by 1.

[0239] Figure 21 and Figure 22The figure illustrates a DAI signaling method according to a first embodiment of the present invention and a method for generating a HARQ-ACK bit sequence based on the DAI signaling method. According to an embodiment of the present invention, DAI can be applied to a TB-based HARQ-ACK bit sequence and a CBG-based HARQ-ACK bit sequence, respectively. Therefore, the base station generates independent counter-DAI and total-DAI values for each transmission scheme. The base station transmits the counter-DAI value and the total-DAI value according to the PDSCH transmission scheme through the counter-DAI field and the total-DAI field of the PDCCH scheduling the PDSCH. The user equipment receives the DCI through the PDCCH transmitted by the base station, distinguishes the transmission scheme (i.e., TB-based transmission or CBG-based transmission) according to the information of the DCI, and receives the DAI corresponding to the transmission scheme. The user equipment can refer to the received DAI to generate the HARQ-ACK bit sequence of the corresponding transmission scheme. In this case, the user equipment can interpret the counter-DAI and the total-DAI received through the PDCCH as the counter-DAI and the total-DAI for the transmission scheme of the PDSCH scheduled by the PDCCH. Table 9 shows a method for the user equipment to interpret the counter-DAI and the total-DAI generated according to the first embodiment of the present invention.

[0240] [Table 9]

[0241]

[0242] Referring to Table 9, the counter-DAI field and the total-DAI field of the PDCCH scheduling the TB-based PDSCH respectively indicate the counter-DAI and the total-DAI for the TB-based transmission. In addition, the counter-DAI field and the total-DAI field of the PDCCH scheduling the CBG-based PDSCH respectively indicate the counter-DAI and the total-DAI for the CBG-based transmission.

[0243] First, the counter-DAI for TB-based transmission can indicate the cumulative number of TB-based PDSCHs scheduled on the previous component carrier from the first component carrier (i.e., CC#0). In this case, if the value of the counter-DAI is C, the cumulative number of TB-based PDSCHs scheduled on the previous component carrier can be C. In a similar manner, the counter-DAI for TB-based transmission can indicate the cumulative number of TB-based PDSCHs scheduled on the current component carrier from the first component carrier (i.e., CC#0). In this case, if the value of the counter-DAI is C, the cumulative number of TB-based PDSCHs scheduled on the current component carrier can be C + 1. Additionally, the total-DAI for TB-based transmission can indicate the total number of TB-based PDSCHs scheduled for the entire component carrier. If the value of the total-DAI is T, the total number of TB-based PDSCHs scheduled for the entire component carrier can be T + 1.

[0244] Next, the counter-DAI for CBG-based transmission can indicate the cumulative number of CBG-based PDSCHs scheduled on the previous component carrier from the first component carrier (i.e., CC#0). In this case, if the value of the counter-DAI is C, the cumulative number of CBG-based PDSCHs scheduled on the previous component carrier can be C. In a similar manner, the counter-DAI for CBG-based transmission can indicate the cumulative number of CBG-based PDSCHs scheduled on the current component carrier from the first component carrier (i.e., CC#0). In this case, if the value of the counter-DAI is C, the cumulative number of CBG-based PDSCHs scheduled on the current component carrier can be C + 1. Additionally, the total-DAI for CBG-based transmission can indicate the total number of CBG-based PDSCHs scheduled for the entire component carrier. If the value of the total-DAI is T, the total number of CBG-based PDSCHs scheduled for the entire component carrier can be T + 1.

[0245] Figure 21 The figure illustrates the DAI signaling method according to the first embodiment above. Refer to Figure 21, the PDSCH can be transmitted to the user equipment via component carriers #0, #1, #3, #4, #5, and #7. Among the component carriers, the CBG-based PDSCH is transmitted via component carriers #0, #3, #5, and #7, and the TB-based PDSCH is transmitted via component carriers #1 and #4. Since the total number of CBG-based PDSCHs scheduled for the entire component carrier is 4, the value of the total-DAI field for CBG-based transmission can be set to 3. Additionally, the value of the counter-DAI field for CBG-based transmission can be set to a value starting from 0 and increasing based on the cumulative number of CBG-based PDSCHs scheduled for the current component carrier. Therefore, the values of the (counter-DAI, total-DAI) fields of the PDCCHs for component carriers #0, #3, #5, and #7 through which the CBG-based PDSCH is transmitted are (0, 3), (1, 3), (2, 3), and (3, 3), respectively. Similarly, since the total number of TB-based PDSCHs scheduled for the entire component carrier is 2, the value of the total-DAI field for TB-based transmission can be set to 1. Additionally, the value of the counter-DAI for TB-based transmission can be set to a value starting from 0 and increasing based on the cumulative number of TB-based PDSCHs scheduled for the current component carrier. Therefore, the values of the (counter-DAI, total-DAI) fields of the PDCCHs for component carriers #1 and #4 through which the TB-based PDSCH is transmitted can be (0, 1) and (1, 1), respectively.

[0246] The user equipment can identify the transmission scheme of the PDSCH by receiving the PDCCH that schedules the PDSCH. For example, the user equipment can identify the transmission scheme of the PDSCH based on the DCI format of the DCI received in the PDCCH. In this case, the user equipment interprets the values of the counter-DAI field and the total-DAI field of the received PDCCH as the counter-DAI and the total-DAI for the transmission scheme of the PDSCH scheduled by the PDCCH, respectively. For example, in Figure 21 the embodiment, when receiving the PDCCH that schedules the PDSCH transmitted via component carrier #3, the user equipment can identify that the CBG-based PDSCH is transmitted via carrier #3 and can interpret the values of the counter-DAI field and the total DAI field of the PDCCH as the counter-DAI and the total-DAI for CBG-based transmission, respectively. Since the received values of the (counter-DAI, total-DAI) field are (1, 3), the user equipment can identify that a total of 4 CBG-based PDSCHs are allocated to the entire component carrier and the PDSCH via component carrier #3 is the second CBG-based PDSCH.

[0247] If the counter-DAI value for CBG-based transmission does not increase sequentially as the component carrier index increases (i.e., not in the order of 0 -> 1 -> 2 -> 3...), the user equipment can determine that the reception of some PDCCHs for scheduling CBG-based transmission has failed. Additionally, if the counter-DAI value of the last successfully received PDCCH among the PDCCHs for scheduling CBG-based transmission and the total-DAI value are not equal to each other, the user equipment can determine that the reception of at least one PDCCH for scheduling CBG-based transmission after the last PDCCH has failed. In this case, the number of PDCCHs for scheduling CBG-based transmission that have not been received after the last successfully received PDCCH can be identified by the difference between the total-DAI value and the counter-DAI value of the last PDCCH. Such a method of interpreting the counter-DAI value and the total-DAI value can be equally applied to the interpretation of the counter-DAI value and the total-DAI value for TB-based transmission.

[0248] Reference Figure 21 , the user equipment may not be able to decode the PDCCHs transmitted through component carriers #3 and #7 where CBG-based transmission is scheduled, and can successfully decode the PDCCHs transmitted through the remaining component carriers #0 and #5 where CBG-based transmission is scheduled. In this case, the user equipment can receive 0 and 2 respectively as the counter-DAI values for CBG-based transmission. Therefore, the user equipment can identify that the reception of the PDCCH corresponding to counter-DAI = 1 among the PDCCHs for scheduling CBG-based transmission has failed. Additionally, since 3 is received as the total-DAI value for CBG-based transmission but the counter-DAI value of the last successfully received PDCCH among the PDCCHs for scheduling CBG-based transmission is 2, the difference between the total-DAI value and the counter-DAI of the last PDCCH is 1. Therefore, the user equipment can identify that the reception of one PDCCH for scheduling CBG-based transmission after the last PDCCH has failed.

[0249] Figure 22The figure illustrates a method for generating a HARQ-ACK bit sequence of DAI transmitted according to the above-described first embodiment. According to an embodiment of the present invention, a user equipment generates a HARQ-ACK bit sequence for an entire component carrier in response to receiving a PDSCH of each component carrier. In this case, the user equipment may generate the HARQ-ACK bit sequence based on a transmission scheme of each identified component carrier. As described above, the HARQ-ACK bit sequence includes a HARQ-ACK bit sequence based on a TB and a HARQ-ACK bit sequence based on a CBG. In addition, the user equipment may generate the HARQ-ACK bit sequence by referring to a DAI of a PDCCH scheduling the PDSCH of each component carrier. In this case, the DAI is applied to the HARQ-ACK bit sequence based on the TB and the HARQ-ACK bit sequence based on the CBG, respectively.

[0250] More specifically, the user equipment may generate a HARQ-ACK bit sequence based on a CBG by combining N-bit HARQ-ACKs for each CBG-based transmission in an order of a counter-DAI value of the CBG-based transmission. Each bit in the HARQ-ACK bit sequence based on the CBG indicates whether a CBG is successfully received. According to an embodiment of the present invention, in the HARQ-ACK bit sequence based on the CBG, N HARQ-ACK bits are generated for each TB, where N is a maximum number of CBGs of each TB configured for the user equipment. In addition, the user equipment may generate a HARQ-ACK bit sequence based on a TB by combining 1-bit or 2-bit HARQ-ACKs for each TB-based transmission in an order of a counter-DAI value of the TB-based transmission. As a reference, the HARQ-ACK for the TB-based transmission may consist of 1 bit per PDSCH when spatial bundling is applied, and may consist of at most 2 bits per PDSCH when spatial bundling is not applied. In Figure 22 the embodiment, it is assumed that 1-bit HARQ-ACK is transmitted as the HARQ-ACK for each TB-based transmission.

[0251] According to another embodiment of the present invention, when the user equipment does not receive any PDCCH scheduling a CBG-based transmission, the CBG-based HARQ-ACK bit sequence can be excluded from the HARQ-ACK bit sequence. That is, the HARQ-ACK bit sequence can consist only of TB-based HARQ-ACK bit sequences. Similarly, when the user equipment does not receive any PDCCH scheduling a TB-based transmission, the TB-based HARQ-ACK bit sequence can be excluded from the HARQ-ACK bit sequence. That is, the HARQ-ACK bit sequence can consist only of CBG-based HARQ-ACK bit sequences. The user equipment can configure the entire HARQ-ACK bit sequence by combining the CBG-based HARQ-ACK bit sequence and the TB-based HARQ-ACK bit sequence. According to an embodiment of the present invention, the user equipment can configure the entire HARQ-ACK bit sequence by appending the CBG-based HARQ-ACK bit sequence to the TB-based HARQ-ACK bit sequence. Refer to Figure 22 , the HARQ-ACK bit sequence configured by the user equipment is [x0 (0) ,x1 (0) ,...,x N-1 (0) ,x0 (1) ,x1 (1) ,...,x N-1 (1) ,x0 (2) ,x1 (2) ,...,x N-1 (2) ,x0 (3) ,x1 (3) ,...,x N-1 (3) ,y0 (0) ,y0 (1) . Here, x is the CBG-based HARQ-ACK bit, and y is the TB-based HARQ-ACK bit. Additionally, the superscript indicates the counter DAI value of the PDCCH that schedules the PDSCH composed of the corresponding CBG or TB, and the subscript indicates the ascending order of the corresponding CBG or TB in the PDSCH.

[0252] Meanwhile, according to the above first embodiment, in order for the user equipment to configure the entire HARQ-ACK bit sequence, the user equipment should receive at least one DAI for TB-based transmission and at least one DAI for CBG-based transmission. That is, the user equipment should receive at least one PDCCH scheduling CBG-based transmission and at least one PDCCH scheduling TB-based transmission. If the user equipment only receives the PDCCH for one transmission method, it cannot identify the scheduling information for the other transmission method. For example, if the user equipment does not successfully receive any PDCCH scheduling TB-based transmission, the user equipment does not know whether the PDCCH for TB-based transmission is sent, and thus will not generate the HARQ-ACK bit sequence for TB-based transmission. In this case, an error may occur in the interpretation of the HARQ-ACK bit sequence between the base station and the user equipment, so a method for solving this problem is needed.

[0253] Figure 23 FIG. illustrates a DAI signaling method according to a second embodiment of the present invention. According to the second embodiment of the present invention, the base station may send a counter-DAI value by the counter-DAI field of the PDCCH scheduling the corresponding PDSCH according to the transmission scheme of the PDSCH, and may send either the total-DAI value for TB-based transmission or the total-DAI value for CBG-based transmission based on the counter-DAI value through the total-DAI field of the PDCCH. That is, according to the second embodiment of the present invention, the counter-DAI field signals the counter-DAI value according to the transmission scheme of the corresponding PDSCH, but the total-DAI field may selectively signal either the total-DAI value according to the corresponding transmission scheme or the total-DAI value according to another transmission scheme based on the value of the counter-DAI field. According to an embodiment, when the counter-DAI value is even, the total-DAI field may indicate the total-DAI value according to the transmission scheme of the corresponding PDSCH, and when the counter-DAI value is odd, the total-DAI field may indicate the total-DAI value according to a transmission scheme other than the transmission scheme of the corresponding PDSCH.

[0254] The user equipment receives DCI through the PDCCH sent by the base station and receives DAI in the DCI format of the DCI. The user equipment can refer to the received DAI to generate a HARQ-ACK bit sequence. In this case, the user equipment can interpret the counter-DAI received through the PDCCH as the counter-DAI for the transmission scheme of the PDSCH scheduled by the PDCCH. On the other hand, the user equipment can identify whether the total-DAI received through the PDCCH is the total-DAI for TB-based transmission or the total-DAI for CBG-based transmission based on the value of the counter-DAI. Table 10 shows the method for the user equipment to interpret the counter-DAI and total-DAI generated according to the second embodiment of the present invention.

[0255] [Table 10]

[0256]

[0257] Referring to Table 10, the counter-DAI field of the PDCCH scheduling the TB-based PDSCH indicates the counter-DAI for TB-based transmission, while the counter-DAI field of the PDCCH scheduling the CBG-based PDSCH indicates the counter-DAI for CBG-based transmission. On the other hand, when the value of the counter-DAI field of the PDCCH is even, the total-DAI field of the PDCCH scheduling the TB-based PDSCH indicates the total-DAI for TB-based transmission, and when the value of the counter-DAI field of the PDCCH is odd, the total-DAI field of the PDCCH scheduling the TB-based PDSCH indicates the total-DAI for CBG-based transmission. Similarly, when the value of the counter-DAI field of the PDCCH is even, the total-DAI field of the PDCCH scheduling the CBG-based PDSCH indicates the total-DAI for CBG-based transmission, and when the value of the counter-DAI field of the PDCCH is odd, the total-DAI field of the PDCCH scheduling the CBG-based PDSCH indicates the total-DAI for TB-based transmission. On the other hand, the information indicated by the counter-DAI and total-DAI for TB-based transmission and the counter-DAI and total-DAI for CBG-based transmission is the same as that in the first embodiment above.

[0258] Figure 23 Illustrate the DAI signaling method according to the second embodiment above. In Figure 23In the embodiment, the case of transmitting the CBG-based PDSCH and the TB-based PDSCH through each component carrier is the same as that of the first embodiment above. In this case, the total number of CBG-based PDSCHs scheduled for the entire component carrier is 4, and the total number of CBG-based PDSCHs scheduled for the entire component carrier is 2. According to the second embodiment, in the DAI for CBG-based transmission, when the counter-DAI value is even, the value of the total-DAI field is set to 3, and when the counter-DAI value is odd, the value of the total-DAI field is set to 1. Therefore, the (counter-DAI, total-DAI) field values of the PDCCHs for component carriers #0, #3, #5, and #7 through which the CBG-based PDSCH is transmitted are (0, 3), (1, 1), (2, 3), and (3, 1), respectively. Similarly, in the DAI for TB-based transmission, when the counter-DAI value is even, the value of the total-DAI field is set to 1, while when the counter-DAI value is odd, the value of the total-DAI field is set to 3. Therefore, the (counter-DAI, total-DAI) field values of the PDCCHs for component carriers #1 and #4 through which the TB-based PDSCH is transmitted can be (0, 1) and (1, 3), respectively.

[0259] The user equipment can identify the transmission scheme of the PDSCH by receiving the PDCCH that schedules the PDSCH. In this case, the user equipment interprets the value of the counter-DAI field of the received PDCCH as the counter-DAI for the transmission scheme of the PDSCH scheduled by the PDCCH. On the other hand, when interpreting the value of the total-DAI field of the received PDCCH, when the counter-DAI value is even, the user equipment interprets it as the total-DAI according to the transmission scheme of the corresponding PDSCH, and when the counter-DAI value is odd, the user equipment interprets it as the total-DAI according to the transmission scheme other than the transmission scheme of the corresponding PDSCH. For example, in Figure 23 the embodiment, when receiving the PDCCH that schedules the PDSCH transmitted through component carrier #3, the user equipment can identify that the CBG-based PDSCH is transmitted through carrier #3, and interprets the value of the counter-DAI field of the PDCCH as the counter-DAI for CBG-based transmission. In this case, since the value of the counter-DAI field is odd, the user equipment can interpret the value of the total-DAI field of the PDCCH as the total-DAI for TB-based transmission. Since the received (counter-DAI, total-DAI) field value is (1, 1), the user equipment can identify that the PDSCH transmitted through component carrier #3 is the second CBG-based PDSCH, and a total of 2 TB-based PDSCHs are allocated to the entire component carrier.

[0260] The method for determining that the user equipment fails to receive the PDCCH scheduling the CBG-based transmission or the TB-based transmission based on the counter-DAI and / or the total-DAI is similar to the first embodiment above. However, in order to obtain the total-DAI for a specific transmission scheme, when the value of the counter-DAI field is even, the user equipment shall refer to the total-DAI field in the PDCCH. Therefore, the total-DAI value of the last PDCCH in the first embodiment above should be replaced with the total-DAI value of the PDCCH in which the value of the counter-DAI field is even. At the same time, in order to obtain the total-DAI for a specific transmission scheme, when the value of the counter-DAI field is odd in the PDCCH scheduling the PDSCH of another transmission scheme, the user equipment may refer to the total-DAI field. The user equipment can determine whether the reception of at least some PDCCHs has failed by referring to the total-DAI for the specific transmission scheme thus obtained.

[0261] At the same time, according to the second embodiment above, even when only the PDCCH scheduling the PDSCH of one transmission scheme is received, the user equipment can also know the number of PDSCHs scheduled by another transmission scheme. Therefore, even if all receptions of the PDCCH scheduling the PDSCH of a specific transmission scheme fail, an error in the interpretation of the HARQ-ACK bit sequence between the base station and the user equipment can be prevented. For example, even if one PDCCH scheduling the TB-based transmission is sent and the user equipment fails to receive the corresponding PDCCH, the user equipment can identify the number of TB-based PDSCHs scheduled by the PDCCH scheduling the CBG-based transmission. However, in the case where only one PDCCH is successfully received, an error in the interpretation of the HARQ-ACK bit sequence between the base station and the user equipment may still occur.

[0262] Figure 24Figure showing the DAI signaling method according to the third embodiment of the present invention. According to the third embodiment of the present invention, the base station can generate independent counter-DAIs for each of the TB-based transmission and the CBG-based transmission, and generate a common total-DAI for both transmission schemes. The base station can send the counter-DAI value by scheduling the counter-DAI field of the PDCCH corresponding to the PDSCH according to the transmission scheme of the PDSCH, and can send the common total-DAI value through the total-DAI field of all PDCCHs. That is, according to the third embodiment of the present invention, the counter-DAI field signals the counter-DAI value according to the transmission scheme of the corresponding PDSCH, but the total-DAI field signals only one of the total-DAI values for the TB-based transmission or the CBG-based transmission. The user equipment can interpret the counter-DAI received through the PDCCH as the counter-DAI for the transmission scheme of the PDSCH scheduled by the PDCCH. In addition, the user equipment can interpret the total-DAI received through the PDCCH as the total-DAI commonly applied to all transmission schemes. Table 11 shows the method by which the user equipment interprets the counter-DAI and the total-DAI generated according to the third embodiment of the present invention.

[0263] [Table 11]

[0264]

[0265] Referring to Table 11, the information indicated by the counter-DAI fields of the PDCCHs scheduling the TB-based PDSCH and the CBG-based PDSCH is the same as in the first and second embodiments described above. However, the total-DAI fields of the PDCCHs scheduling the TB-based PDSCH and the CBG-based PDSCH represent the common total-DAI. The common total-DAI value can be determined according to various embodiments. If at least one TB-based PDSCH and at least one CBG-based PDSCH are scheduled for the entire component carrier, the common total-DAI value can be expressed as the total number of PDSCHs of any one of the transmission schemes scheduled for the entire component carrier. According to an embodiment, the common total-DAI value can indicate the total number of CBG-based PDSCHs scheduled for the entire component carrier. According to another embodiment, the common total-DAI value can be determined as the value that minimizes the length of the HARQ-ACK bit sequence. If only PDSCHs of any one of the transmission schemes are scheduled for the entire component carrier, the common total-DAI value can be determined as a predetermined value. According to an embodiment of the present invention, when using a 2-bit total-DAI, the predetermined value can be binary "11". In addition, when using a 3-bit total-DAI, the predetermined value can be "011" or "111".

[0266] Figure 24 The figure illustrates the DAI signaling method according to the third embodiment above. In Figure 24 the embodiment, the case of transmitting the CBG-based PDSCH and the TB-based PDSCH through each component carrier is the same as that of the first embodiment above. According to the embodiment, when the common total-DAI value represents the total number of CBG-based PDSCHs, the total-DAI fields for CBG-based transmission and the total-DAI fields for TB-based transmission are both set to 3. Therefore, the values of the (counter-DAI, total-DAI) fields of the PDCCHs of component carriers #0, #3, #5, and #7 through which the CBG-based PDSCH is transmitted are (0, 3), (1, 3), (2, 3), and (3, 3), respectively. In addition, the values of the (counter-DAI, total-DAI) fields of the PDCCHs of component carriers #1 and #4 through which the TB-based PDSCH is transmitted can be (0, 3) and (1, 3), respectively.

[0267] The user equipment can identify the transmission scheme of the PDSCH by receiving the PDCCH that schedules the PDSCH. In this case, the user equipment interprets the value of the counter-DAI field of the received PDCCH as the counter-DAI of the transmission scheme of the PDSCH scheduled by the PDCCH. On the other hand, the user equipment interprets the value of the total-DAI field of the received PDCCH as the total-DAI applied to both CBG-based transmission and TB-based transmission. For example, in Figure 24 the embodiment, when receiving the PDCCH that schedules the PDSCH transmitted through component carrier #3, the user equipment can identify that the CBG-based PDSCH is transmitted through carrier #3 and interpret the value of the counter-DAI field of the PDCCH as the counter-DAI for CBG-based transmission. In addition, the user equipment can interpret the value of the total-DAI field of the PDCCH as the total-DAI applied to both CBG-based transmission and TB-based transmission. Since the received value of the (counter-DAI, total-DAI) field is (1, 3), the user equipment can identify that the PDSCH transmitted through component carrier #3 is the second CBG-based PDSCH, and a total of 4 CBG-based PDSCHs and TB-based PDSCHs are respectively allocated to the entire component carrier. On the other hand, although the total-DAI fields for CBG-based transmission and the total-DAI fields for TB-based transmission both signal the common total-DAI value, the total numbers of the scheduled CBG-based PDSCHs and TB-based PDSCHs may not be the same as each other. That is, if the total-DAI field consists of B bits and signals the common total-DAI value k, the total number of scheduled CBG-based PDSCHs can be 2B *n + k + 1, and the total number of TB-based PDSCHs scheduled can be 2 B *m + k + 1 (where n and m are non-negative integers). Thus, if the total-DAI field consists of two bits, the difference between the total number of CBG-based PDSCHs scheduled and the total number of TB-based PDSCHs scheduled can be a multiple of 4.

[0268] The method for determining, by a user equipment, that a PDCCH for scheduling a CBG-based transmission or a TB-based transmission has not been received based on a counter-DAI and / or a total-DAI is similar to the first embodiment described above. However, if the received common-DAI indicates a predetermined value and a PDCCH for scheduling a PDSCH of a specific transmission scheme has not been received, the user equipment may determine that the PDSCH of the specific transmission scheme has not been scheduled. When generating a HARQ-ACK bit sequence, the user equipment may not multiplex the HARQ-ACK bit sequence for the specific transmission scheme determined to be unscheduled. For example, if the common total-DAI indicates a predetermined value and a PDCCH for scheduling a TB-based transmission has not been received, the HARQ-ACK bit sequence generated by the user equipment may be configured by excluding the TB-based HARQ-ACK bit sequence. Similarly, if the common total-DAI indicates a predetermined value and a PDCCH for scheduling a CBG-based transmission has not been received, the HARQ-ACK bit sequence generated by the user equipment may be configured by excluding the CBG-based HARQ-ACK bit sequence. On the other hand, if a PDCCH for scheduling a PDSCH of a specific transmission scheme has not been received but the common total-DAI does not indicate a predetermined value, the user equipment may determine that the PDSCH of the specific transmission scheme has been scheduled, but the user equipment cannot receive the PDSCH. Thus, when generating a HARQ-ACK bit sequence, the user equipment may multiplex the HARQ-ACK bit sequence for the corresponding transmission scheme. According to an embodiment of the present invention, when using a 2-bit total-DAI, the predetermined value may be binary "11". Additionally, when using a 3-bit total-DAI, the predetermined value may be "011" or "111". Additionally, according to an embodiment of the present invention, the method of not multiplexing the HARQ-ACK bit sequence for a specific transmission scheme may be applied only when the HARQ-ACK bit sequence is sent via a PUSCH. That is, when the common total-DAI indicates a predetermined value and a PDCCH for scheduling a PDSCH of a specific transmission scheme has not been received, and the HARQ-ACK bit sequence is sent via a PUSCH, then the user equipment may not multiplex the HARQ-ACK bit sequence for the specific transmission scheme.

[0269] Meanwhile, according to the third embodiment of the present invention, since a common total - DAI is used, a mismatch may occur in the total - DAI of a specific transmission scheme. Therefore, in the case of a specific transmission scheme, different from the total number of PDSCHs scheduled for the specific transmission scheme, the user equipment can generate a HARQ - ACK bit sequence based on the total number information according to the common total DAI - value. For example, if the decoding of the PDCCHs transmitted through component carriers #1 and #4 where TB - based transmissions are scheduled is successful, the user equipment can receive values 0 and 1 respectively as the counter - DAI for the TB - based transmissions. Meanwhile, the user equipment receives a value 3 as the total - DAI for the TB - based transmissions. Since the value 3 is received as the total - DAI value for the TB - based transmissions, but the counter - DAI value of the last successfully received PDCCH among the PDCCHs scheduling the TB - based transmissions is 1, the difference between the total - DAI value and the counter - DAI value of the last PDCCH is 2. Therefore, the user equipment can recognize that the reception of two PDCCHs scheduling the TB - based transmissions has failed after the last PDCCH. On the other hand, since the base station knows the actual total number of scheduled TB - based PDSCHs different from the common total - DAI value, the base station may ignore the sent NACK due to the mismatch.

[0270] Figure 25 and Figure 26 FIG. illustrates an embodiment of generating a HARQ - ACK bit sequence based on the DAI signaled according to the above - described third embodiment. Figure 25 FIG. illustrates an embodiment where the common total - DAI value represents the total number of CBG - based PDSCHs, and Figure 26 FIG. illustrates an embodiment where the common total - DAI value represents the total number of TB - based PDSCHs. The method of generating a HARQ - ACK bit sequence based on the DAI signaled according to the third embodiment of the present invention is similar to the first embodiment described with reference to Figure 22 However, if the common total - DAI indicates a predetermined value and no PDCCH for scheduling a PDSCH of a specific transmission scheme is received, the user equipment may not multiplex the HARQ - ACK bit sequence for the specific transmission scheme when generating the HARQ - ACK bit sequence.

[0271] First, referring to Figure 25 , the common total - DAI value indicates the total number of CBG - based PDSCHs, and the value of the total - DAI field is 3. If the total - DAI field consists of 2 bits, it can be interpreted that the total number of CBG - based PDSCHs scheduled for the entire component carrier is 2 2 *n + 3 + 1 = 4*(n + 1), and the total number of TB - based PDSCHs scheduled for the entire component carrier is 2 2*m + 3 + 1 = 4(m + 1) (where n and m are non - negative integers). The user equipment can generate a CBG - based HARQ - ACK bit sequence and a TB - based HARQ - ACK bit sequence respectively, and combine the two HARQ - ACK bit sequences to configure the entire HARQ - ACK bit sequence. According to Figure 25 In the embodiment of (2) , since the value of the total - DAI field is 3, the TB - based HARQ - ACK bit sequence can include HARQ - ACK for virtual TB - based PDSCHs (i.e., PDSCH TB - tx#2, #3) in addition to 2 TB - based PDSCHs (i.e., PDSCH TB - tx#0, #1) [y0 (3) ,y0 Figure 25 . Here, the HARQ - ACK bit sequence configured by the user equipment is [x0 (0) ,x1 (0) ,...,x N-1 (0) ,x0 (1) ,x1 (1) ,...,x N-1 (1) ,x0 (2) ,x1 (2) ,...,x N-1 (2) ,x0 (3) ,x1 (3) ,...,x N-1 (3) ,y0 (0) ,y0 (1) ,y0 (2) ,y0 (3) . Here, the last two bits [y0 (2) ,y0 (3) of the TB - based HARQ - ACK bit sequence are dummy bits with useless information for preventing errors in the interpretation of the HARQ - ACK bit sequence between the base station and the user equipment.

[0272] Next, referring to Figure 26 , the common total - DAI value indicates the total number of TB - based PDSCHs, and the value of the total - DAI field is 1. If the total - DAI field consists of 2 bits, it can be interpreted that the CBG - based PDSCH for the entire component carrier scheduling is 2 2*n + 1 + 1 = 4*n + 2, and the total number of TB-based PDSCHs scheduled for the entire component carrier is 2 2 *m + 1 + 1 = 4m + 2 (where n and m are non-negative integers). The user equipment can generate a CBG-based HARQ-ACK bit sequence and a TB-based HARQ-ACK bit sequence respectively, and combine the two HARQ-ACK bit sequences to configure the entire HARQ-ACK bit sequence. According to Figure 26 the embodiment of, since the value of the total-DAI field is 1, the TB-based HARQ-ACK bit sequence can include the HARQ-ACK[x0 (4) ,x1 (4) ,...,x N-1 (4) ,x0 (5) ,x1 (5) ,...,x N-1 (5) of the virtual CBG-based PDSCHs (i.e., PDSCH CBG-tx#4,#5) in addition to the 4 CBG-based PDSCHs (i.e., PDSCH CBG-tx#0,#1,#2,#3). The user equipment can configure the entire HARQ-ACK bit sequence by appending the CBG-based HARQ-ACK bit sequence after the TB-based HARQ-ACK bit sequence. Refer to Figure 26 , the HARQ-ACK bit sequence configured by the user equipment is [x0 (0) ,x1 (0) ,...,x N-1 (0) ,x0 (1) ,x1 (1) ,...,x N-1 (1) ,x0 (2) ,x1 (2) ,...,x N-1 (2) ,x0 (3) ,x1 (3) ,...,x N-1 (3) ,x0 (4) ,x1 (4) ,...,x N-1 (4) ,x0 (5) ,x1 (5) ,...,x N-1 (5) ,y0 (0) ,y0 (1) . Here, the last 2N bits [x0 (4), x1 (4) ,..., x N-1 (4) , x0 (5) , x1 (5) ,..., x N-1 (5) are dummy bits with useless information for preventing errors in the interpretation of the HARQ-ACK bit sequence between the base station and the user equipment.

[0273] Figure 27 FIG. illustrates another embodiment of generating a HARQ-ACK bit sequence by signaling the DAI according to the third embodiment above. As described above, according to another embodiment of the present invention, only one of the CBG-based transmission and the TB-based transmission can be scheduled for the PDSCH. In this case, in order to signal the PDSCH that schedules only any one of the transmission schemes, the total-DAI value can be set to a predetermined value 3 (i.e., binary "11"). Additionally, in Figure 27 the embodiment, it is assumed that the TB-based PDSCH is transmitted through component carriers #1 and #4, and the CBG-based PDSCH is not scheduled.

[0274] First, Figure 27 (a) shows an embodiment in which the value of the total-DAI field indicates the total number of TB-based PDSCHs. Since the number of TB-based PDSCHs scheduled for the entire component carrier is 2, the value of the total-DAI field is set to 1. In this case, the total number of CBG-based PDSCHs scheduled for the entire component carrier can be interpreted as 2. Therefore, the user equipment can generate 2*N bits of HARQ-ACK[x0 (0) , x1 (0) ,..., x N-1 (0) , x0 (1) , x1 (1) ,..., x N-1 (1) . Since the user equipment can only detect the PDCCH that schedules the TB-based PDSCH, the 2*N bits of HARQ-ACK can be set to all NACKs as dummy bits.

[0275] Next, Figure 27(b) shows an embodiment in which the value of the total - DAI field indicates a predetermined value representing a PDSCH for which a specific transmission scheme is not scheduled. Here, the predetermined value is 3 (i.e., binary "11"). Since the received total - DAI indicates the predetermined value and no PDCCH for scheduling the CBG - based PDSCH is received, the user equipment can determine that the CBG - based PDSCH is not scheduled. Thus, in addition to the CBG - based HARQ - ACK bit sequence, the user equipment can generate an entire HARQ - ACK bit sequence that includes only the TB - based HARQ - ACK bit sequence. In this case, since the value of the total - DAI field is 3, the user equipment can interpret that the total number of TB - based PDSCHs scheduled for the entire component carrier is 4. However, since the user equipment can actually receive two TB - based PDSCHs, it can generate 2 - bit HARQ - ACK for two virtual TB - based PDSCHs (2) ,y0 (3) . Since the user equipment cannot receive the PDCCH for scheduling the virtual TB - based PDSCH, the 2 - bit HARQ - ACK can be set to all NACKs as dummy bits.

[0276] Meanwhile, in the above - mentioned embodiment, it is assumed that one HARQ - ACK bit is generated for each TB in the TB - based HARQ - ACK bit sequence, and N HARQ - ACK bits are generated for each TB in the CBG - based HARQ - ACK bit sequence. In the following embodiments, it can be assumed that any one of 1 to N HARQ - ACK bits is generated for each TB in the CBG - based HARQ - ACK bit sequence. For example, the length of the HARQ - ACK bits for the CBG - based PDSCH can be determined based on the number of CBGs actually scheduled and transmitted in the PDSCH. Additionally, in the following embodiments, it can be assumed that the TB - based transmission consists of 1 CBG - based transmission. That is, each embodiment can be described by assuming that a PDSCH consisting of 1 TB is a PDSCH consisting of 1 CBG, and a PDSCH consisting of 2 TBs is a PDSCH consisting of 2 CBGs. Thus, the separate expression of the TB - based transmission or the CBG - based transmission can be omitted. For reference, the user equipment can identify whether the TB - based transmission or the CBG - based transmission is applied to the PDSCH scheduled by the PDCCH through the information of the PDCCH.

[0277] Figure 28The figure shows a DAI signaling method according to a fourth embodiment of the present invention. According to the fourth embodiment of the present invention, the base station may generate a counter-DAI value and a total-DAI value based on the number of scheduled CBGs, and transmit them through the counter-DAI field and the total-DAI field. That is, the counter-DAI represents the cumulative number of CBGs scheduled from the first component carrier (i.e., component carrier #0) to the previous component carrier. In addition, the total-DAI represents the total number of CBGs scheduled for the entire component carrier. Refer to Figure 28 , the PDSCH can be transmitted to the user equipment through component carriers #0, #1, #3, #4, #5, and #7. In this case, the number of CBGs transmitted through component carriers #0, #1, #3, #4, #5, and #7 can be 2, 3, 1, 4, 3, and 3 respectively. Since the total number of CBGs scheduled for the entire component carrier is 16, the values of the (counter-DAI, total-DAI) fields for each PDCCH for component carriers #0, #1, #3, #4, #5, and #7 can be (0, 16), (2, 16), (5, 16), (6, 16), (10, 16), and (13, 16) respectively.

[0278] When the user equipment receives the PDCCH, the user equipment can identify the number of CBGs included in the PDSCH scheduled by the PDCCH through the CBG scheduling information included in the PDCCH. In addition, the user equipment can identify the total number of CBGs scheduled for the entire component carrier through the total-DAI value, and identify the transmission order of the CBGs included in the PDSCH scheduled by the corresponding PDCCH through the counter-DAI value. If the PDSCH scheduled by the current PDCCH contains k CBGs and the value of the (counter-DAI, total-DAI) field is (C, T), then the PDSCH scheduled for the entire component carrier includes a total of T CBGs and the CBGs included in the PDSCH scheduled by the current PDCCH are the (C + 1)-th to the (C + k)-th among the total T CBGs. For example, when the user equipment successfully receives the PDCCH that schedules the PDCCH transmitted through component carrier #3, the user equipment can identify, based on the CBG scheduling information included in the PDCCH, that the PDSCH transmitted through component carrier #3 includes 1 CBG. In addition, the user equipment can identify, through the received value (5, 16) of the (counter-DAI, total-DAI) field, that a total of 16 CBGs are scheduled for the entire component carrier and the CBG included in the PDSCH transmitted through component carrier #3 is the sixth CBG among the total 16 CBGs.

[0279] The user equipment may generate a HARQ-ACK bit sequence in the following manner. First, the length of the HARQ-ACK bit sequence may be determined based on the total-DAI value. If the total-DAI field consists of B bits and the value of the total-DAI field is T, the length of the HARQ-ACK bit sequence may be 2 B *n + T. Here, n is a non-negative integer and may be the minimum value allowed for including the HARQ-ACK bits of the CBGs included in the PDSCH scheduled by the successfully received PDCCH in the HARQ-ACK bit sequence. The user equipment may determine the positions of the HARQ-ACK bits of the CBGs scheduled by the corresponding PDCCH based on the counter-DAI value obtained from the successfully received PDCCH and the number k of the scheduled CBGs. That is, when the value of the counter-DAI field is C, the positions of the HARQ-ACK bits in the HARQ-ACK bit sequence may be from the (C + 1)-th to the (C + k)-th. If the counter-DAI field consists of A bits and the value of the counter-DAI field is C, the available positions of the HARQ-ACK bits are from the 2 A *m + C + 1 to the 2 A *m + C + k. Here, m is a non-negative integer. Meanwhile, the bits of the unmapped HARQ-ACK bits in the HARQ-ACK bit sequence may be set to NACK.

[0280] Meanwhile, according to the fourth embodiment described above, when the user equipment successfully receives a PDCCH, the total number of CBGs scheduled for the entire component carrier and the transmission order of the CBGs included in the PDSCH scheduled by the corresponding PDCCH may be identified. However, since various numbers of CBGs may be transmitted by one PDSCH, when the user equipment identifies the failure to receive multiple CBGs, it cannot identify the number of PDSCHs that have not been received.

[0281] Figure 29 FIG. illustrates a DAI signaling method according to a fifth embodiment of the present invention. According to the fifth embodiment of the present invention, the base station generates a first counter-DAI (i.e., counter-DAI #1) value and a first total-DAI (i.e., total-DAI #1) value based on the number of scheduled PDSCHs, and generates a second counter-DAI (i.e., counter-DAI #2) value and a second total-DAI (i.e., total-DAI #2) value based on the number of CBGs. The base station may transmit the generated DAI values through a first counter-DAI field, a first total-DAI field, a second counter-DAI field, and a second total-DAI field, respectively.

[0282] First, the first counter - DAI represents the cumulative number of PDSCHs scheduled from the first component carrier (i.e., component carrier #0) to the previously component - carrier - scheduled PDSCHs. In this case, if the value of the first counter - DAI is C, the cumulative number of PDSCHs scheduled to the previous component carrier can be C (i.e., the cumulative number of PDSCHs scheduled to the current component carrier is C + 1). Additionally, the first total - DAI represents the total number of PDSCHs scheduled for all component carriers. If the value of the first total - DAI is T, the total number of PDSCHs scheduled for all component carriers can be T + 1.

[0283] Next, the second counter - DAI is determined based on the cumulative number of CBGs scheduled from the first component carrier (i.e., component carrier #0) to the previously component - carrier - scheduled CBGs. Additionally, the second total - DAI is determined based on the total number of CBGs scheduled for all component carriers. According to an embodiment of the present invention, in order to reduce signaling overhead, the values of the second counter - DAI field and the second total - DAI field can be set by subtracting the value of the first counter - DAI field and the value of the first total - DAI field from the information to be signaled, respectively. For example, if the number of CBGs scheduled to the previous component carrier is P and the first counter - DAI value for the current component carrier is C1, the second counter - DAI value C2 for the current component carrier can be set as C2 = P - C1. Further, if the total number of CBGs scheduled for all component carriers is Q and the first total - DAI value is T1, the second total - DAI value T2 can be set as T2 = Q - T1.

[0284] In Figure 29 the embodiment of, the case of transmitting CBGs through each component carrier is the same as the fourth embodiment described above. In this case, the values of the (first counter - DAI, first total - DAI, second counter - DAI, second total - DAI) fields for each PDCCH of component carriers #0, #1, #3, #4, #5, #7 are (0, 5, 0, 11), (1, 5, 1, 11), (2, 5, 3, 11), (3, 5, 3, 11), (4, 5, 6, 11), and (5, 5, 8, 11).

[0285] When a user equipment receives a PDCCH, the user equipment can identify the number of CBGs included in the PDSCH scheduled by the PDCCH through the CBG scheduling information included in the PDCCH. In addition, the user equipment can identify the total number of PDSCHs scheduled for the entire component carrier through a first total-DAI value, and can identify the transmission order of the PDSCH scheduled by the corresponding PDCCH through a first counter-DAI value. In addition, the user equipment can identify the total number of CBGs scheduled for the entire component carrier through a second total-DAI value, and identify the transmission order of the CBGs included in the PDSCH scheduled by the corresponding PDCCH through a second counter-DAI value. If the PDSCH scheduled by the current PDCCH includes k CBGs, and the value of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) field is (C1, T1, C2, T2), the total number of PDSCHs scheduled for the entire component carrier is T1 + 1 and the total number of CBGs scheduled for the entire component carrier is T1 + T2. In addition, among a total of T1 + T2 CBGs, the order of the PDSCH scheduled by the current PDCCH is the C1-th, and the CBGs included in the PDSCH are the (C1 + C2 + 1)-th to the (C1 + C2 + k)-th CBGs.

[0286] If the first counter-DAI value does not increase sequentially as the component carrier index increases (i.e., not in the order of 0 -> 1 -> 2 -> 3...), the user equipment determines that the reception of some PDCCHs has failed. In addition, if the first counter-DAI value and the first total-DAI value of the last successfully received PDCCH are not equal to each other, the user equipment can determine that the reception of at least one PDCCH has failed after the last PDCCH. In this case, the number of PDCCHs that have not been received after the last successfully received PDCCH can be identified by the difference between the first total-DAI value and the first counter-DAI value of the last PDCCH.

[0287] The user equipment may generate a HARQ-ACK bit sequence in the following manner. First, the length of the HARQ-ACK bit sequence may be determined based on the sum of the first total DAI value and the second total DAI value. The user equipment may determine the positions of the HARQ-ACK bits for the CBGs scheduled by the corresponding PDCCH based on the first counter DAI value and the second counter DAI value obtained from the successfully received PDCCH and the number k of the scheduled CBGs. That is, when the value of the (first counter DAI, first total DAI, second counter DAI, second total DAI) field is (C1, T1, C2, T2), the positions of the HARQ-ACK bits in the HARQ-ACK bit sequence may be from the (C1 + C2 + 1)-th to the (C1 + C2 + k)-th. Meanwhile, the bits in the HARQ-ACK bit sequence where the HARQ-ACK bits are not mapped may be set to NACK.

[0288] Meanwhile, according to the fifth embodiment described above, when the user equipment successfully receives a PDCCH, it may identify the total number of CBGs scheduled for the entire component carrier and the transmission order of the CBGs included in the PDSCH scheduled by the corresponding PDCCH. In addition, when the user equipment fails to receive at least one PDSCH, it may identify which PDSCH fails to be received. However, according to this embodiment, there may be a drawback of high DCI overhead.

[0289] Figure 30 FIG. illustrates a DAI signaling method according to a sixth embodiment of the present invention. According to the sixth embodiment of the present invention, the base station generates a first counter DAI (i.e., counter DAI #1) value and a first total DAI (i.e., total DAI #1) value based on the number of scheduled PDSCHs, and generates a second counter DAI (i.e., counter DAI #2) value based on the number of CBGs. The base station may transmit the generated DAI values through a first counter DAI field, a first total DAI field, and a second counter DAI field, respectively.

[0290] In a sixth embodiment of the present invention, the definitions of the first counter-DAI and the first total-DAI are the same as those in the above-described fifth embodiment. However, the second counter-DAI is determined based on the number of CBGs scheduled in K PDSCHs before the current component carrier. According to an embodiment of the present invention, the K PDSCHs before the current component carrier can be determined cyclically. That is, if a total of k PDSCHs (where k < K) are scheduled from the first component carrier (i.e., component carrier #0) to the previous component carrier, the K PDSCHs can include the k PDSCHs from the first component carrier to the previous component carrier and K - k PDSCHs in reverse order starting from the last component carrier. According to an embodiment, the value of K can be determined based on the value of the first total-DAI (i.e., the total number of CBGs scheduled for the entire component carrier). For example, when the value of the first total-DAI is 1, 2, or 3, the value of K can be set to 0, 1, or 2. In addition, when the value of the first total-DAI is greater than 3, the value of K can be set to 3. According to an embodiment of the present invention, in order to reduce signaling overhead, the value of the second counter-DAI field can be set by subtracting K from the number of CBGs scheduled in K PDSCHs before the current component carrier.

[0291] In Figure 30 an embodiment of, the case of transmitting CBGs through each component carrier is the same as that in the above-described fourth embodiment. In this case, the value of K can be set to 3, and the values of the (first counter-DAI, first total DAI, second counter-DAI) fields are (0, 5, 7), (1, 5, 5), (2, 5, 5), (3, 5, 3), (4, 5, 5), and (5, 5, 5).

[0292] The method for determining that the user equipment fails to receive some PDCCHs is the same as that in the fifth embodiment. Additionally, in the sixth embodiment, since the second counter-DAI is determined based on the number of CBGs scheduled in the K PDSCHs before the current component carrier, the user equipment can identify the number of CBGs included in the PDSCH scheduled by the PDCCH that fails to be received based on the second counter-DAI. For example, it can be assumed that the user equipment fails to receive the PDCCH in which the value of the first counter-DAI is 2 and successfully receives the remaining PDCCHs. Since there is no value 2 among the values of the first counter-DAI of the successfully received PDCCHs, the user equipment can identify the reception failure of the PDCCH in which the value of the first counter-DAI is 2. The number of CBGs included in the PDSCH scheduled by the PDCCH in which the value of the first counter-DAI is 2 can be identified based on the value obtained by subtracting the number of CBGs included in the PDSCHs scheduled by the PDCCHs in which the values of the first counter-DAI are 0 and 1 from the value of the second counter-DAI of the PDCCH in which the value of the first counter-DAI is 3. In Figure 30 the embodiment of, the value of the second counter-DAI of the PDCCH in which the value of the first counter-DAI is 3 is 3, and the numbers of CBGs included in the PDSCHs scheduled by the PDCCHs in which the values of the first counter-DAI are 0 and 1 are 2 and 3, respectively. Therefore, the number x of CBGs included in the PDSCH scheduled by the PDCCH in which the value of the first counter-DAI is 2 satisfies (2 + 3 + x) - K = 3. Here, since K is 3, the user equipment can identify x as 1.

[0293] Figure 31FIG. illustrates an embodiment of generating a HARQ-ACK bit sequence by signaling DAI according to the sixth embodiment above. As in the above embodiments, the user equipment can identify the number of PDSCHs transmitted through a component carrier based on a first counter-DAI value and a first total-DAI value. In addition, the user equipment can identify the number of CBGs transmitted through each component carrier based on a second counter-DAI value. Therefore, the user equipment can sequentially increase the value of the first counter-DAI field from 0 to the first total-DAI value, and generate a HARQ-ACK bit sequence by combining HARQ-ACK bits for the PDSCHs scheduled by the corresponding PDCCH. However, when the value of K is 2 or greater (e.g., when K = 2 or 3), the user equipment can cyclically increase the value of the first counter-DAI field from i, and generate a HARQ-ACK bit sequence by combining HARQ-ACK bits for the PDSCHs scheduled by the corresponding PDCCH. In this case, in order to indicate the value of i, a header indicating configuration information of the HARQ-ACK bit sequence can be added at the beginning or end of the HARQ-ACK bit sequence. That is, the HARQ-ACK bit sequence can include a header and a main bit sequence. The header indicates information about which PDSCH of the HARQ-ACK bits the main bit sequence starts from.

[0294] Reference Figure 31 , when the value of K is 2 or 3, the candidates for the HARQ-ACK bit sequence that can be transmitted by the user equipment can be 4. Therefore, the header consists of two bits and indicates which PDSCH of the HARQ-ACK bits the main bit sequence starts from. For example, if the header indicates "00", the main bit sequence starts from the HARQ-ACK bit of the first PDSCH. Similarly, if the header indicates "01", "10", or "11", the main bit sequence starts from the HARQ-ACK bits of the second, third, or fourth PDSCHs, respectively.

[0295] Meanwhile, according to the sixth embodiment, when the user equipment successfully receives a PDCCH, it can identify the total number of PDSCHs scheduled for the entire component carrier and the transmission order of the PDSCHs scheduled by the corresponding PDCCH. In addition, the user equipment can identify information about the number of CBGs based on the second counter-DAI value. According to the sixth embodiment, since the second total-DAI field is not transmitted, the DCI signaling overhead can be reduced compared to the fifth embodiment. However, since a header should be added to the HARQ-ACK bit sequence transmitted by the user equipment, the UCI transmission overhead may increase.

[0296] Figure 32FIG. illustrates a DAI signaling method according to a seventh embodiment of the present invention. According to the seventh embodiment of the present invention, a base station separates a transmission type into a first type of transmission and a second type of transmission based on the number of CBGs included in a scheduled PDSCH, and independently generates a first counter-DAI (i.e., counter-DAI #1) and a first total-DAI (i.e., total-DAI #1) value, and a second counter-DAI (i.e., counter-DAI #2) and a second total-DAI (i.e., total-DAI #2) value based on the number of PDSCHs for each transmission type. The base station may send DAI values of the same type as the transmission type of the PDSCH scheduled by the PDCCH through a first counter-DAI field, a first total-DAI field, a second counter-DAI field, and a second total-DAI field of the PDCCH. When a user equipment receives the PDCCH, the user equipment may identify the number of CBGs included in the PDSCH scheduled by the PDCCH through CBG scheduling information included in the PDCCH. In addition, the user equipment may identify the transmission type of the PDSCH based on the number of CBGs included in the PDSCH. The user equipment interprets the values of the first counter-DAI field, the first total-DAI field, the second counter-DAI field, and the second total-DAI field received through the PDCCH as DAI values for the identified transmission type.

[0297] According to an embodiment of the present invention, the first type of transmission is a transmission of a PDSCH composed of a predetermined number or less of CBGs, and the second type of transmission is a transmission of a PDSCH composed of more than the predetermined number of CBGs. According to an embodiment, the predetermined number may be or Here, N may be the maximum number of CBGs per TB configured in the user equipment, is the largest natural number less than or equal to x, and is the smallest natural number greater than or equal to x. In the following embodiments, it is assumed that the predetermined number is However, according to this embodiment, it may be replaced with or other values.

[0298] Based on the first type of transmission, the DAI values for the first type of transmission are applied to the PDSCH and CBG, and the definition of the DAI values is the same as those in the fifth embodiment above. Similarly, based on the second type of transmission, the DAI values for the second type of transmission are applied to the PDSCH and CBG. However, in the DAI for the second type of transmission, the first counter-DAI and the first total-DAI can be set in the same manner as in the fifth embodiment above, but the second counter-DAI and the second total-DAI can be set to have a granularity different from that according to the fifth embodiment. That is, since the minimum number of the minimum CBGs included in the PDSCH for performing the second type of transmission is Therefore, the second counter-DAI value and the second total-DAI value for the second type of transmission are set by subtracting the value based on the minimum number to reduce the signaling overhead. More specifically, if the number of CBGs for the second type of transmission scheduled to the previous component carrier is P and the first counter-DAI value of the current component carrier is C1, the second counter-DAI value C2 of the current component carrier can be set to In addition, if the total number of CBGs for the second type of transmission scheduled for the entire component carrier is Q and the first total-DAI value is T1, the second total-DAI value T2 can be set to

[0299] Reference Figure 32 , the PDSCH can be sent to the user equipment through component carriers #0, #1, #3, #4, #5, and #7. In this case, the number of CBGs sent through component carriers #0, #1, #3, #4, #5, and #7 can be 2, 3, 1, 4, 3, and 4, respectively. If N = 4, the PDSCHs scheduled in component carriers #0 and #3 are PDSCHs based on the first type of transmission, and the PDSCHs scheduled in component carriers #1, #4, #5, and #7 are PDSCHs based on the second type of transmission. Therefore, the values of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields of each PDCCH for component carriers #0 and #3 where the PDSCH based on the first type of transmission is scheduled can be (0, 1, 0, 1) and (1, 1, 1, 1), respectively. In addition, the values of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7 where the PDSCH based on the second type of transmission is scheduled can be (0, 3, 0, 2), (1, 3, 0, 2), (2, 3, 1, 2), and (3, 3, 1, 2), respectively. Table 12 shows a method for the user equipment to interpret the counter-DAI and total-DAI generated according to the seventh embodiment of the present invention.

[0300] [Table 12]

[0301]

[0302] Referring to Table 12, the user equipment can identify the number of PDSCHs of the corresponding transmission type scheduled to the component carrier and the transmission order of the PDSCHs of the transmission type scheduled by the PDCCH through the values of the first counter-DAI field and the first total-DAI field of the PDCCH. In addition, the user equipment can identify the number of CBGs included in the PDSCH of the corresponding transmission type scheduled to the component carrier and the transmission order of the CBGs included in the PDSCH of the transmission type scheduled by the PDCCH through the values of the second counter-DAI field and the second total-DAI field of the PDCCH. If the PDSCH scheduled by the current PDCCH contains k CBGs and the transmission type is x (where x = 1 or 2), and the values of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields are (C1, T1, C2, T2), then the total number of PDSCHs of type x transmitted scheduled for the entire component carrier is T1 + 1 and the order of the PDSCHs of type x transmitted scheduled by the current PDCCH is the (C1 + 1)-th. In addition, the CBGs included in the PDSCH of type x are from the M x *(C1 + C2 + 1)-th to the M x *(C1 + C2 + k)-th CBGs. Here, when x = 1, M x = 1, and when x = 2 Meanwhile, the method for determining that the user equipment fails to receive some PDCCHs is the same as that in the above embodiments.

[0303] Figure 33FIG. illustrates an embodiment of generating a HARQ-ACK bit sequence by signaling-based DAI according to the seventh embodiment above. First, the user equipment may combine HARQ-ACKs for PDSCH based on the first type of transmission in the order of the first counter-DAI value to generate a HARQ-ACK sequence based on the first type. Additionally, the user equipment may combine HARQ-ACKs for PDSCH based on the second type of transmission in the order of the first counter-DAI value to generate a HARQ-ACK sequence based on the second type. In this case, "NACK" may be used as the HARQ-ACK for PDSCH for which the reception of PDCCH has failed. According to an embodiment, if the PDCCH scheduling the first type of transmission is not received, the HARQ-ACK bit sequence generated by the user equipment may be configured to exclude the HARQ-ACK bit sequence for the first type of transmission. Similarly, if the PDCCH scheduling the second type of transmission is not received, the HARQ-ACK bit sequence generated by the user equipment may be configured to exclude the HARQ-ACK bit sequence for the second type of transmission. The user equipment may configure the entire HARQ-ACK bit sequence by combining the HARQ-ACK bit sequence for the first type of transmission and the HARQ-ACK bit sequence for the second type of transmission in a predetermined order. According to an embodiment, the user equipment may configure the entire HARQ-ACK bit sequence by appending the HARQ-ACK bit sequence for the first type of transmission to the HARQ-ACK bit sequence for the second type of transmission. Refer to Figure 33 , the HARQ-ACK bit sequence configured by the user equipment is [x0 (0) , x1 (0) , x2 (0) , x0 (1) , x1 (1) , x2 (1) , x3 (1) , x0 (2) , x1 (2) , x2 (2) , x0 (3) , x1 (3) , x2 (3) , x3 (3) , y0 (0) , y1 (0) , y0 (1) . However, the present invention is not limited thereto, and the entire HARQ-ACK bit sequence may be configured by combining the bit sequences in the reverse order.

[0304] Meanwhile, according to the seventh embodiment, the transmission type can be separated into a first type of transmission and a second type of transmission according to the number of CBGs included in the PDSCH, and independent DAI values for each transmission type can be signaled to reduce the overhead of DCI. However, there is a drawback that the user equipment should always receive the PDCCHs scheduling different transmission types.

[0305] Figure 34 FIG. is a schematic diagram illustrating a DAI signaling method according to an eighth embodiment of the present invention. The eighth embodiment of the present invention can be implemented by combining at least some components of the second embodiment and the seventh embodiment described above. That is, the base station separates the transmission type into a first type of transmission and a second type of transmission according to the number of CBGs included in the scheduled PDSCH, and separately generates a first counter-DAI (i.e., counter-DAI#1) and a first total-DAI (i.e., total-DAI#1) value, and a second counter-DAI (i.e., counter-DAI#2) and a second total-DAI (i.e., total-DAI#2) value based on the number of PDSCHs of each transmission type. In this case, when the first counter-DAI value is an even number, the base station can send the first total-DAI value and the second total-DAI value for the same type as the transmission type of the PDSCH scheduled by the PDCCH through the first total-DAI field and the second total-DAI field, respectively. However, when the first counter-DAI value is an odd number, the base station can send the first total-DAI value and the second total-DAI value for a type different from the transmission type of the PDSCH scheduled by the PDCCH through the first total-DAI field and the second total-DAI field, respectively. In this case, the definition of the DAI value is the same as that in the seventh embodiment described above.

[0306] In Figure 34In the embodiment, the case of transmitting CBG through each component carrier is the same as that of the seventh embodiment above. The PDSCH scheduled on component carriers #0 and #3 is a PDSCH based on the first type of transmission, and the PDSCH scheduled on component carriers #1, #4, #5, and #7 is a PDSCH based on the second type of transmission. Therefore, the values of the (first counter - DAI, first total - DAI, second counter - DAI, second total - DAI) fields for each PDCCH of component carriers #0 and #3 where the PDSCH based on the first type of transmission is scheduled can be (0, 1, 0, 1) and (1, 3, 1, 2), respectively. In addition, the values of the (first counter - DAI, first total - DAI, second counter - DAI, second total - DAI) fields for each PDCCH of component carriers #1, #4, #5, and #7 where the PDSCH based on the second type of transmission is scheduled can be (0, 3, 0, 2), (1, 1, 0, 1), (2, 3, 1, 2), and (3, 1, 1, 1), respectively. Meanwhile, the method for generating the HARQ - ACK bit sequence based on the DAI signaled according to the eighth embodiment is the same as that of the above Figure 33 embodiment.

[0307] Meanwhile, according to the eighth embodiment, the transmission type can be separated into a first type of transmission and a second type of transmission according to the number of CBGs included in the PDSCH, and independent DAI values can be signaled for each transmission type to reduce the overhead of DCI. Additionally, even when only the PDCCH for scheduling the PDSCH based on one transmission type is received, the user equipment can know the number of PDSCHs and CBGs based on the other transmission type. However, the user equipment should always receive multiple PDCCHs indicating the total - DAI of different types.

[0308] Figure 35FIG. is a schematic diagram of a DAI signaling method according to a ninth embodiment of the present invention. The ninth embodiment of the present invention can be implemented by combining at least some components of the above-described third and seventh embodiments. That is, the base station separates the transmission type into a first type of transmission and a second type of transmission according to the number of CBGs included in the scheduled PDSCH, and separately generates a first counter-DAI (i.e., counter-DAI #1) value based on the number of PDSCHs and a second counter-DAI (i.e., counter-DAI #2) value based on the number of CBGs for each transmission type. In addition, the base station generates a common first total-DAI (i.e., total-DAI #1) value and a common second total-DAI (i.e., total-DAI #2) value that are used together for both transmission types. The base station transmits the first counter-DAI value and the second counter-DAI value by scheduling the first counter-DAI field and the second counter-DAI field of the PDCCH corresponding to the PDSCH according to the transmission type of the PDSCH. In addition, the base station can transmit the common first total-DAI value and the common second total-DAI value through the first total-DAI field and the second total-DAI field of all PDCCHs, regardless of the transmission type.

[0309] According to another embodiment, when scheduling the PDSCH of any one transmission type only for the entire component carrier, the common first total-DAI value can be determined as a predetermined value. According to an embodiment of the present invention, when using 2-bit total-DAI, the predetermined value can be binary "11". In addition, when using 3-bit total-DAI, the predetermined value can be "011" or "111". At the same time, the method for determining the first counter-DAI value and the second counter-DAI value is the same as the method of the above-described seventh embodiment.

[0310] In Figure 35 the embodiment of, the case of transmitting CBGs through each component carrier is the same as that of the above-described seventh embodiment. In addition, it can be assumed that the common first total-DAI value and the common second total-DAI value are determined based on the number of PDSCHs and CBGs for the second type of transmission, respectively. Therefore, the values of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields of each PDCCH for component carriers #0 and #3 in which the PDSCH based on the first type of transmission is scheduled can be (0, 3, 0, 2) and (1, 3, 1, 2), respectively. In addition, the values of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7 in which the PDSCH based on the second type of transmission is scheduled can be (0, 3, 0, 2), (1, 3, 0, 2), (2, 3, 1, 2), and (3, 3, 1, 2), respectively.

[0311] Figure 36 The figure illustrates an embodiment of generating a HARQ-ACK bit sequence by signaling-based DAI according to the ninth embodiment above. The HAQR-ACK bit sequence can be generated in the same manner as the embodiment above Figure 33 . However, since (3, 2) is used instead of (1, 1) as the value of the (first total-DAI, second total-DAI) field for the PDSCH based on the first type of transmission, the virtual HARQ-ACK [z0, z1, z2] for the virtual CBGs included in the two virtual PDSCHs can be further included in the HARQ-ACK bit sequence.

[0312] Figure 37 The figure illustrates a DAI signaling method according to the tenth embodiment of the present invention. When the base station configures CBG-based transmission, the number of CBGs for each TB configured in each component carrier or cell can be different from each other. For example, the number of CBGs for each TB in component carrier #0 can be configured to 2, and the number of CBGs for each TB in component carrier #1 can be configured to 4. Additionally, when the user equipment is configured in a transmission mode in which two TBs can be transmitted in one PDSCH, the number of CBGs for each TB can be set equally in the two TBs.

[0313] A user equipment configured in a transmission mode in which one TB can be transmitted in one PDSCH should send HARQ-ACK bits to the base station based on the configured number of CBGs. If a user equipment configured in a transmission mode in which two TBs can be transmitted in one PDSCH is configured not to perform spatial bundling, the user equipment should send HARQ-ACK bits to the base station based on twice the number of CBGs configured for each TB. On the other hand, if a user equipment configured in a transmission mode in which two TBs can be transmitted in one PDSCH is configured to perform spatial bundling, the user equipment should send HARQ-ACK bits to the base station based on the number of CBGs configured for each TB. In the following embodiments of the present invention, it is assumed that the user equipment is configured to perform spatial bundling or is configured in a transmission mode in which one TB can be transmitted in one PDSCH. Specific embodiments of the HARQ-ACK bundling method including spatial bundling will be described later. However, the embodiments of the present invention can be extended to user equipment configured in a transmission mode in which two TBs can be transmitted in one PDSCH and is configured not to perform spatial bundling.

[0314] According to an embodiment of the present invention, the DCI of the PDCCH scheduling the PDSCH may include a counter-DAI and a total-DAI. In this case, the counter-DAI represents the cumulative number of CBG groups scheduled from the first component carrier (i.e., component carrier #0) to the previous component carrier, and the total-DAI represents the total number of CBG groups scheduled for the entire component carrier. Here, a CBG group is a set of a predetermined number S of CBGs. According to an embodiment, the TB-based PDSCH in the counter-DAI and the total-DAI can be regarded as the same as the CBG-based transmission composed of S CBGs. That is, it can be assumed that the TB-based PDSCH includes one CBG group. Therefore, even if the TB-based PDSCH is received, the user equipment should feedback S-bit HARQ-ACK. The S-bit HARQ-ACK can be generated by repeating the 1-bit TB-based HARQ-ACK, or by mapping the NACK to the remaining bits. For example, if the total-DAI value is 3, the user equipment can determine that a total of 3*S CBGs have been sent through the entire component carrier. Therefore, the user equipment should send a total of 3*S bits of HARQ-ACK. If two TBs are sent in one PDSCH and spatial bundling is not performed, the user equipment should send a total of 2*3*S bits of HARQ-ACK.

[0315] Table 13 shows the number of CBGs indicated by each DAI value when the total-DAI field and the counter-DAI field are composed of two bits. In addition, Table 14 shows the number of CBGs indicated by each DAI value when the total-DAI field and the counter-DAI field are composed of 3 bits.

[0316] [Table 13]

[0317]

[0318] [Table 14]

[0319]

[0320] In Table 13 and Table 14, the subscript c indicates the index of the component carrier (or cell). That is, V DL C-DAI,c is the counter-DAI value of component carrier C, and V DL T-DAI is the total-DAI value. According to the signaling method of Table 13 and Table 14, when the total-DAI or counter-DAI value is A, the number of CBGs indicated by the corresponding DAI field is S*(2^B+A). Here, B is the bit width of the counter-DAI or the total-DAI. According to an embodiment of the present invention, the number S of CBGs included in one CBG group can be expressed as the granularity with respect to the number of CBGs represented by the counter-DAI or the total-DAI.

[0321] According to an embodiment of the present invention, the number S of CBGs included in a CBG group can be determined by various methods. According to the embodiment, the value of S can be fixed to S = 2. Preferably, S can be configured with a UE-specific RRC signal. According to another embodiment, S can be determined as the greatest common divisor value of the number of CBGs configured in each component carrier. For example, if 2 CBGs are configured in component carrier #0 and 6 CBGs are configured in component carrier #1, it can be set to S = 2. In addition, if 4 CBGs are configured in component carrier #0 and 8 CBGs are configured in component carrier #1, it can be set to S = 4.

[0322] According to yet another embodiment, in a transmission mode where one TB can be transmitted in one component carrier, the value of S can be fixed to S = 2, and in a transmission mode where two TBs can be transmitted in one component carrier, the value of S can be fixed to S = 4. According to yet another embodiment, when all component carriers are configured in a transmission mode where only one TB can be transmitted, S can be determined as the greatest common divisor value of the number of CBGs configured in each component carrier. Additionally, in a transmission mode where two TBs can be transmitted in one component carrier, S can be determined as twice the greatest common divisor value of the number of CBGs configured in each component carrier. For example, in a transmission mode where two TBs can be transmitted in one component carrier, if 2 CBGs are configured in component carrier #0 and 6 CBGs are configured in component carrier #1, it can be set to S = 4. Additionally, if 4 CBGs are configured in component carrier #0 and 8 CBGs are configured in component carrier #1, it can be set to S = 8.

[0323] The bit widths of the counter - DAI field and the total - DAI field expected by the user equipment can vary according to the number S of CBGs included in a CBG group. According to an embodiment, the bit widths of the counter - DAI field and the total - DAI field can be set to 2 + ceil(log2(X / S)), respectively. In this case, X is the maximum number of CBGs configured for each component carrier of the user equipment. Here, ceil(a) represents the smallest integer greater than or equal to "a". For example, if two component carriers are configured for the user equipment, and the number of CBGs configured in component carrier #0 is 2 and the number of CBGs configured in component carrier #1 is 4, then S = 2. In this case, the bit widths of the counter - DAI field and the total - DAI field can be set to 2 + ceil(log2(4 / 2)) = 3 bits, respectively. Additionally, if two component carriers are configured in the user equipment and the number of CBGs configured in component carrier #0 is 4 and the number of CBGs configured in component carrier #1 is 8, then S = 4. In this case, the bit widths of the counter - DAI field and the total - DAI field can be set to 2 + ceil(log2(8 / 4)) = 3 bits, respectively.

[0324] Reference Figure 37 , the PDSCH can be sent to the user equipment via component carriers #0, #1, #3, #4, #5, and #7. In this case, the number of CBGs sent via component carriers #0, #1, #3, #4, #5, and #7 can be 2, 4, 6, 8, 2, and 4, respectively. According to an embodiment of the present invention, the number S of CBGs included in a CBG group is set to 2, which is the greatest common divisor of the numbers of CBGs. Therefore, the values of the (counter - DAI, total - DAI) fields for each PDCCH for component carriers #0, #1, #3, #4, #5, and #7 can be (0, 13), (1, 13), (3, 13), (6, 13), (10, 13), and (11, 13).

[0325] Figure 38 FIG. illustrates a HARQ - ACK compression method according to an embodiment of the present invention. If the length of the HARQ - ACK payload that a user equipment configured for CBG - based transmission should send exceeds the maximum transmission capacity of the PUCCH, the HARQ - ACK payload should be compressed to fit the maximum transmission capacity of the PUCCH.

[0326] According to an embodiment of the present invention, the user equipment can send TB - based HARQ - ACKs for some TBs (or PDSCHs) in the entire TB and send CBG - based HARQ - ACKs for the remaining TBs (or PDSCHs). Reference Figure 38, the HARQ-ACK payload of the user equipment can consist of the following three parts. First, the "header" part notifies the method to interpret the following HARQ-ACK payload. More specifically, the "header" can notify the index of the TB (or PDSCH) in which the CBG-based HARQ-ACK is sent. Alternatively, the "header" can notify the index of the TB (or PDSCH) in which the TB-based HARQ-ACK is sent. Next, the "TB-A / N" field includes the TB-based HARQ-ACK for the TB (or PDSCH) in which the "header" indicates the transmission of the TB-based HARQ-ACK. In this case, the order of the TB-based HARQ-ACKs can be set in ascending order of the counter-DAI value of the TB (or PDSCH). Next, the "CBG-A / N" field includes the CBG-based HARQ-ACK for the TB (or PDSCH) in which the "header" indicates the transmission of the CBG-based HARQ-ACK. In this case, the order of the CBG-based HARQ-ACKs can be set in ascending order of the counter-DAI value of the TB (or PDSCH). For reference, if the number of bits of the CBG-based HARQ-ACK for different TBs is different, NACK can be appended so that the length of the CBG-based HARQ-ACK payload for each TB is equal to the bit length of the longest CBG-based HARQ-ACK among each CBG-based HARQ-ACK.

[0327] The "header" part can be set as follows. When transmitting HARQ-ACKs for a total of X TBs, the user equipment can transmit CBG-based HARQ-ACKs for c of the X TBs and transmit TB-based HARQs for the remaining X - c TBs. Here, the method for determining the value of c by the user equipment and the base station will be described later. The "header" part represents information for selecting c from X TBs. The "header" can consist of a bitmap with an X-bit length. Each bit can indicate information about whether to transmit a TB-based HARQ-ACK or a CBG-based HARQ-ACK for each TB. In another embodiment, the number of cases of selecting c from X TBs is Here, is the binomial coefficient. Therefore, the number of bits required for the "header" is The "header" can indicate the value And the method for interpreting the value is as follows. First, it can be assumed that the value of the "header" is "i". The (i + 1)-th smallest (or largest) binary sequence among the binary sequences of length X with c number of 1s and X - c number of 0s can be obtained. In this case, in the binary sequence, it can be interpreted that the index where 1 is located is the index of the TB (or PDSCH) that sends the CBG-based HARQ-ACK, and the index where 0 is located is the index of the TB (or PDSCH) that sends the TB-based HARQ-ACK. For example, when X = 4 and c = 2, the "header" can indicate values from 0 to 5. If the value of the "header" is any one of 0 to 5, it can match 0011, 0101, 0110, 1001, 1010, or 1100 respectively. If the value of the "header" is 2, it matches 0110. Thus, the CBG-based HARQ-ACK can be sent for the second and third TBs (or PDSCHs), and the TB-based HARQ-ACK can be sent for the first and fourth TBs (or PDSCHs).

[0328] According to an embodiment of the present invention, the user equipment and the base station can determine the value of c in the following manner. The base station and the user equipment can know the maximum number of transmission bits that the PUCCH for sending HARQ-ACK can send. Assume that the maximum number of transmission bits is B. In addition, assume that the length of the CBG-based HARQ-ACK payload is N. The user equipment and the base station can identify how many TBs (or PDSCHs) are scheduled for the entire component carrier by the total-DAI value. Assume that the total number of scheduled TBs (or PDSCHs) is X. In this case, c can be determined as the largest integer that satisfies Equation 1 below.

[0329] [Equation 1]

[0330]

[0331] In Equation 1, since the values of X, N, and B are known to the user equipment and the base station, the user equipment and the base station can identify the value of c without error. For reference, when determining the value of c, the length of the HARQ-ACK payload sent by the user equipment is The base station may always expect a HARQ-ACK payload with the above length.

[0332] For example, when X = 9, B = 22, and N = 4, c = 2 can be obtained according to Equation 1 above. Therefore, when generating HARQ-ACK, the user equipment can configure N-bit CBG-based HARQ-ACK for 2 out of a total of 9 TBs (or PDSCHs), and can configure 1-bit TB-based HARQ-ACK for the remaining 7 TBs (or PDSCHs). In this case, the base station always expects 21-bit HARQ-ACK. When the 21-bit HARQ-ACK received by the base station is [001111101100011101010], the interpretation of the HARQ-ACK is as follows. In the HARQ-ACK, since the "header" is so the value of the "header" is [001111], that is, 15. Since the 16th smallest binary sequence in the binary sequence of length 15 is [001000001], CBG-based HARQ-ACK is sent for the third and ninth TBs (or PDSCHs), and TB-based HARQ-ACK is sent for the first, second, fourth, fifth, sixth, seventh, and eighth TBs (or PDSCHs). The X - c = 9 - 2 = 7 bits following the "header" are the "TB-A / N" field. The value [1011000] of the corresponding field indicates the TB-based HARQ-ACK of the first, second, fourth, fifth, sixth, seventh, and eighth TBs (or PDSCHs). The c * N = 2 * 4 = 8 bits following the "TB-A / N" field are the "CBG-A / N" field. The value [11101010] of the corresponding field indicates the CBG-based HARQ-ACK of the third and ninth TBs (or PDSCHs). That is, the CBG-based HARQ-ACK of the third TB (or PDSCH) is 1110, and the CBG-based HARQ-ACK of the ninth TB (or PDSCH) is 1010.

[0333] Figure 39 and Figure 40 FIG. illustrates a method for performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. When a user equipment configured with a transmission mode in which two TBs can be sent in one PDSCH and configured with CBG-based transmission performs spatial bundling, the CBG-based HARQ-ACK for each TB should be bundled. In addition, the user equipment can be configured to spatially bundle the CBG-based HARQ-ACKs sent through different time slots. The method for performing spatial bundling according to an embodiment of the present invention is as follows. For reference, a method for performing spatial bundling is described, but this method can be used when bundling HARQ-ACKs between two different TBs.

[0334] When the same maximum number N of CBGs is configured for each TB, assume that the number of CBGs included in TB#1 is M1, the number of CBGs included in TB#2 is M2, and M1 is greater than or equal to M2. That is, assume that TB#1 contains the same or more CBGs than TB#2. If TB#2 includes more CBGs than TB#1, the embodiments of the present invention can be applied by changing the indices of TB#1 and TB#2. If the user equipment is configured not to perform bundling, the user equipment shall send a total of 2*N bits of HARQ-ACK, N bits for each TB. In this case, if M1 < N, it can be expressed that the TB includes M1 CBGs and N - M1 virtual CBGs. Assume that the N-bit HARQ-ACK for TB#1 is [a1,a2,...,a M1 ,x,...,x], and the N-bit HARQ-ACK for TB#2 is [b1,b2,...,b M2 ,x,...,x]. Here, x is the value filled with the HARQ-ACK for the virtual CBG to facilitate matching the length of the HARQ-ACK payload, and can be mapped to NACK later.

[0335] First, Figure 39 FIG. illustrates a first embodiment of performing spatial bundling of HARQ-ACK. More specifically, Figure 39 (a) to 39(c) illustrate respective embodiments of performing spatial bundling of HARQ-ACK when M1 = N and M2 = 1 to 3. When M1 = N, the indices of the CBGs for performing bundling among the CBGs included in the 2 TBs can be selected such that the resource elements assigned to the two CBGs overlap as much as possible in the time-frequency domain. This is because the higher the overlap as much as possible in the time-frequency domain, the higher the expected correlation. More specifically, when M1 = N, the indices of the CBGs for performing bundling among the CBGs included in the two TBs can follow the values in Table 15 according to the M1 value and the M2 value.

[0336] [Table 15]

[0337] M1＝2 M1＝4 M2＝1 {1} {1} M2＝2 {1,2} {1,4} M2＝3 - {1，2,4} M2＝4 - {1,2,3，4}

[0338] Referring to Table 15, when M1 = 4 and M2 = 2, the value {1,4} can be obtained as the index of the CBGs for performing bundling. Therefore, referring to Figure 39(b), the first CBG of TB#2 can be bundled with the first CBG of TB#1, and the second CBG of TB#2 can be bundled with the fourth CBG of TB#1. Additionally, when M1 = 4 and M2 = 3, the values {1, 2, 4} can be obtained as the indices of the CBGs where bundling is performed. Thus, referring to 39(c), the first CBG of TB#2 can be bundled with the first CBG of TB#1, the second CBG of TB#2 can be bundled with the second CBG of TB#1, and the third CBG of TB#2 can be bundled with the fourth CBG of TB#1.

[0339] Table 16 illustrates another method of performing spatial bundling according to the first embodiment above. When M1 = N, the indices of the CBGs where bundling is performed among the CBGs included in the two TBs can follow the values in Table 16 according to the M1 and M2 values.

[0340] [Table 16]

[0341] M1＝2 M1＝4 M2＝1 {1} {1} M2＝2 {1,2} {1,4} M2＝3 - {1，3,4} M2＝4 - {1，2，3,4}

[0342] Referring to Table 16, when M1 = 4 and M2 = 3, the values {1, 3, 4} can be obtained as the indices of the CBGs where bundling is performed. Thus, the first CBG of TB#2 is bound to the first CBG of TB#1, the second CBG of TB#2 is bound to the third CBG of TB#1, and the third CBG of TB#2 can be bound to the fourth CBG of TB#1.

[0343] Next, Figure 40 Illustrates a second embodiment of performing spatial bundling of HARQ-ACK. More specifically, Figure 40 (a) to 40(f) show various embodiments of performing spatial bundling of HARQ-ACK when M1 < N. If M1 < N, some HARQ-ACK bits of TB#2 are preferentially mapped to the HARQ-ACK bits that are not used (or used for virtual CBGs) in TB#1, and bundling of the remaining HARQ-ACK bits of TB#2 and the HARQ-ACK bits of TB#1 can be performed. First, Figure 40 (a) to 40(c) show embodiments where M1 < N and M1 + M2 is less than or equal to N. In this case, the N-bit HARQ-ACK where spatial bundling is performed can consist of the M1-bit HARQ-ACK of TB#1, the M2-bit HARQ-ACK of TB#2, and N - (M1 + M2) bits of NACK. Figure 40(d) to 40(f) illustrate embodiments in which M1 < N and M1 + M2 is greater than N and less than 2*N. In this case, M1 + M2 - N bits among the HARQ-ACKs of TB#1 can be configured by bundling (i.e., binary AND operation) M1 + M2 - N bits among the HARQ-ACKs of TB#2 in the N-bit HARQ-ACK in which spatial bundling is performed. Additionally, 2*N - (M1 + M2) bits among the N-bit HARQ-ACK on which spatial bundling is performed can be composed of the remaining N - M2 bits among the HARQ-ACKs of TB#1 and the remaining N - M1 bits among the HARQ-ACKs of TB#2.

[0344] In a more specific embodiment, [b1, b2,..., b M2 can be divided into [b1, b2,…, b M2-k and [b M2-k+1 , b M2-k+2 ,…, b M2 . Here, k satisfies k = N - M1. Additionally, a binary AND operation can be performed between [b1, b2,…, b M2-k and [a1, a2,…, a M2-k . The result obtained in this way is [c1, c2,…, c M2-k . The finally bundled HARQ-ACK can be obtained by sequentially connecting [c1, c2,…, c M2-k , [a M2-k+1 , a M2-k+1 ,..., a M1 , [b M2-k+1 , b M2-k+2 ,…, b M2 . According to an embodiment of the present invention, the connection order of the HARQ-ACK can be changed. As a reference, when the length of the connected HARQ-ACK is less than N bits, x can be appended to the HARQ-ACK to adjust the length to N bits. In this case, x can be mapped to NACK. Finally, when the HARQ-ACK on which bundling is performed is [o1, o2,…, o N , the HARQ-ACK bit o i can be obtained according to the value of the index i, as shown in Equation 2.

[0345] [Equation 2]

[0346]

[0347] Here, & represents the binary AND operation. Additionally, K = N - M1 and α = max{N - (M1 + M2), 0}. In this case, max{s, t} returns the larger number between s and t. Here, x can be mapped to NACK.

[0348] In another embodiment of the present invention, when the HARQ-ACK to which bundling is finally performed is [o1, o2, …, o N , the HARQ-ACK bit o according to the value of the index i can be obtained i , as shown in Equation 3.

[0349] [Equation 3]

[0350]

[0351] Here, λ is M1 + M2 - N. Additionally, x can be mapped to NACK.

[0352] Referring to Equation 2, Equation 3, and Figure 40 , the HARQ-ACK for the final bundling of the HARQ-ACKs for two TBs is as follows. Referring to Figure 40 (a), if the HARQ-ACKs for two TBs are [a1, x, x, x] and [b1, x, x, x], then the finally bundled HARQ-ACK is [a1, b1, x, x]. Referring to Figure 40 (b), if the HARQ-ACKs for two TBs are [a1, a2, x, x] and [b1, x, x, x], then the finally bundled HARQ-ACK is [a1, a2, b1, x]. Referring to Figure 40 (c), if the HARQ-ACKs for two TBs are [a1, a2, x, x] and [b1, b2, x, x], then the finally bundled HARQ-ACK is [a1, a2, b1, b2]. Referring to Figure 40 (d), if the HARQ-ACKs for two TBs are [a1, a2, a3, x] and [b1, x, x, x], then the finally bundled HARQ-ACK is [a1, a2, a3, b1]. Referring to Figure 40 (e), if the HARQ-ACKs for two TBs are [a1, a2, a3, x] and [b1, b2, x, x], then the finally bundled HARQ-ACK is [a1 & b1, b2, x, x]. Here, & is the binary AND operation. Referring to Figure 40(f), if the HARQ-ACKs for two TBs are [a1, a2, a3, x] and [b1, b2, b3, x], then the finally bundled HARQ-ACK is [a1&b1, a2&b2, a3, b3]. Further, if the HARQ-ACKs for two TBs are [a1, a2, a3, a4] and [b1, b2, b3, x], then the finally bundled HARQ-ACK is [a1&b1, a2&b2, a3&b3, a4].

[0353] Figure 41 and 42 More specifically, a method for performing spatial bundling of HARQ-ACK according to an embodiment of the present invention is illustrated. In Figure 41 and 42 , N is the maximum number of CBGs for each TB configured by the RRC signal, M1 is the number of CBGs included in TB#1, and M2 is the number of CBGs included in TB#2. Additionally, the HARQ-ACK bit for the i-th CBG of TB#1 is a i , and the HARQ-ACK bit for the i-th CBG of TB#2 is b i . In this case, & represents a binary AND operation. Additionally, x can be mapped to NACK.

[0354] According to an embodiment of the present invention, the DCI for a user equipment configured with a transmission mode in which 2 TBs can be transmitted in one PDSCH and configured with CBG-based transmission can be set as follows. First, it can be assumed that each TB is configured with N CBGs. If the user equipment is configured not to perform spatial bundling, in order to indicate which CBG is transmitted for each TB, there is an N-bit CBG transmission information (CBGTI) field for each TB in the DCI of the user equipment. Additionally, there is a modulation and coding scheme (MCS), a redundancy version (RV), and a new data indicator (NDI) for each TB. If the CBGTI is all 0 for one TB, it may indicate that the TB is not transmitted. Further, if the CBGTI is all 0 for one TB and the values of MCS and RV are specific values, it may indicate that the TB is not transmitted. The specific value of MCS can be 0, and the specific value of RV can be 1.

[0355] According to another embodiment of the present invention, if there is at least one virtual CBG in two TBs used for performing bundling, bundling can be performed as follows. First, for the virtual CBG, NACK can be mapped to HARQ-ACK "x". Additionally, Q = min(M1, M2) can be defined. For reference, it is assumed that when TB#1 is TB-based transmission, M1 = 1, and when TB#2 is TB-based transmission, M2 = 1. ACK is 1, and NACK is 0. When generating the bundled HARQ-ACK from the HARQ-ACKs for two TBs, a binary AND operation can be performed on the first to the Q-th HARQ-ACK bits, and a binary OR operation can be performed on the (Q + 1)-th to the N-th HARQ-ACK bits. If TB#1 contains 4 CBGs (i.e., M1 = 4) and the number of configured CBGs is 4 (i.e., N = 4), and TB#2 contains 2 CBGs (i.e., M2 = 2) and the number of configured CBGs is 4 (i.e., N = 4), then the HARQ-ACK for TB#1 is [a1, a2, a3, a4], and the HARQ-ACK for TB#2 is [b1, b2, 0, 0]. Additionally, Q = 2. Therefore, a binary AND operation is performed on the first two bits, and a binary OR operation is performed on the following two bits (i.e., as N - Q). Thus, the bundled HARQ-ACK is [a1&b1, a2&b2, a3|0, a4|0]. Here, & is the binary AND operation, and | is the binary OR operation. For reference, this bundling method can be used in spatial bundling or can be used only in bundling among other TBs except spatial bundling.

[0356] According to another embodiment of the present invention, if there is at least one virtual CBG in two TBs for which bundling is performed, the bundling can be carried out as follows. First, the HARQ-ACK for the virtual CBG is represented by "x", and after bundling, NACK is mapped to "x". When generating the bundled HARQ-ACK from the HARQ-ACKs for the two TBs, a ternary AND operation can be performed on the two HARQ-ACKs. In this case, the truth table of the ternary AND operation is shown in Table 17. After bundling, x can be mapped to NACK. If TB#1 contains 4 CBGs (i.e., M1 = 4) and the number of configured CBGs is 4 (i.e., N = 4), and TB#2 contains 2 CBGs (i.e., M2 = 2) and the number of configured CBGs is 4 (i.e., N = 4), then the HARQ-ACK for TB#1 is [a1, a2, a3, a4], and the HARQ-ACK for TB#2 is [b1, b2, x, x]. Therefore, the bundled HARQ-ACK is [a1\b1, a2\b2, a3\x, a4\x]. The position of the operator \ is shown in Table 17. For reference, this bundling method can be used for spatial bundling, or can be used only for bundling among other TBs except for spatial bundling.

[0357] [Table 17]

[0358]

[0359] On the other hand, if the user equipment is configured to perform spatial bundling, there is an N-bit CBGTI field in the DCI of the user equipment. In addition, for each TB, there are MCS, RV, and NDI. The process of determining which CBG the user equipment has received is as follows. The user equipment can identify whether to transmit the corresponding TB through the values of MCS and RV of each TB. Here, if the MCS and RV are specific values, it means that the corresponding TB has not been transmitted yet. For example, the specific value of MCS can be 0, and the specific value of RV can be 1. If there is a transmitted TB, the user equipment can interpret which CBG of the TB the N-bit CBGTI indicates has been transmitted. That is, if the nth bit of the N-bit CBGTI is 1 (assuming the value 1 represents transmission), the user equipment can identify that the nth CBG has been transmitted. When there are two transmitted TBs, the user equipment can identify which CBG is transmitted among each TB through the N-bit CBGTI in the same way as the method of performing spatial bundling on HARQ-ACK. For example, if the i-th HARQ-ACK bit for which spatial bundling is performed is calculated by performing a binary AND operation on the HARQ-ACK bit of the k-th CBG of TB#1 and the HARQ-ACK bit of the j-th CBG of TB#2, when the i-th bit of the N-bit CBGTI in the DCI is 1, it can indicate that the k-th CBG of TB#1 is transmitted, and the j-th CBG of TB#2 is transmitted. As an embodiment of the present invention, assuming M1 < N and spatial bundling is performed in the same way as in Equation 4, when the i-th bit among the N-bit CBGTI [d1, d2,..., d N is 1, the following CBG can be identified as being transmitted.

[0360] [Equation 4]

[0361]

[0362] Here, CBG (1) i represents the i-th CBG of TB#1, and CBG (2) i represents the i-th CBG of TB#2. M1 and M2 are the numbers of CBGs scheduled in TB#1 and TB#2 respectively, which can be identified from the MCS values of each TB in the DCI.

[0363] Figure 43It is a block diagram illustrating the configurations of a terminal and a base station according to an embodiment of the present invention. In an embodiment of the present invention, the terminal can be implemented as various types of wireless communication devices or computing devices that are guaranteed to be portable and mobile. The terminal can be referred to as a user equipment (UE), a station (STA), a mobile subscriber (MS), etc. Additionally, in an embodiment of the present invention, the base station controls and manages cells corresponding to service areas (e.g., macro cells, femto cells, pico cells, etc.), and can perform functions such as transmitting signals, allocating channels, monitoring channels, self-diagnosis, relaying, etc. The base station can be referred to as a next-generation node B (gNB) or an access point (AP).

[0364] As illustrated, a user equipment 100 according to an embodiment of the present invention may include a processor 110, a communication module 120, a memory 130, a user interface unit 140, and a display unit 150.

[0365] First, the processor 110 may execute various commands or programs and process internal data of the user equipment 100. In addition, the processor 100 may control the overall operation of each unit including the user equipment 100, and control data transmission and reception between the units. In this case, the processor 110 may be configured to perform operations according to the embodiments described in the present invention. For example, the processor 110 may 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.

[0366] Next, the communication module 120 may be an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 120 may include multiple network interface cards (NICs) in an internal or external form, such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123. Although the communication module 120 is illustrated as an integrated module in the drawings, different from the drawings, each network interface card may be independently arranged according to a circuit configuration or purpose.

[0367] The cellular communication interface card 121 may transmit and receive wireless signals to / from at least one of a base station 200, an external device, and a server by using a mobile communication network, and may provide cellular communication services through a first band based on a command of the processor 110. According to an embodiment, the cellular communication interface card 121 may include at least one NIC module that uses a band below 6 GHz. At least one NIC module of the cellular communication interface card 121 may independently perform cellular communication with at least one of the base station 200, an external device, and a server according to a cellular communication standard or protocol of a band below 6 GHz supported by the corresponding NIC module.

[0368] The cellular communication interface card 122 can transmit and receive wireless signals with at least one of the base station 200, external devices, and servers by using a mobile communication network, and can provide cellular communication services through a second frequency band based on a command from the processor 110. According to an embodiment, the cellular communication interface card 122 may include at least one NIC module using a frequency band above 6 GHz. 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, external devices, and servers according to a cellular communication standard or protocol of a frequency band above 6 GHz supported by the corresponding NIC module.

[0369] The unauthorized band communication interface card 123 transmits and receives wireless signals with at least one of the base station 200, external devices, and servers by using a third frequency band as an unauthorized band, and provides communication services for the unauthorized band through a second frequency band based on a command from the processor 110. The unauthorized band communication interface card 123 may include at least one NIC module using an unauthorized band. For example, the unlicensed band may be a frequency band of 2.4 GHz or 5 GHz. At least one NIC module of the unauthorized band communication interface card 123 can independently perform wireless communication with at least one of the base station 200, external devices, and servers according to an unauthorized band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0370] Next, the memory 130 stores control programs used in the user equipment 100 and various data according thereto. Such control programs may include predetermined programs necessary for the user equipment 100 to perform wireless communication with at least one of the base station 200, external devices, and servers.

[0371] Next, the user interface 140 includes various types of input / output devices provided in the user equipment 100. That is, the user interface 140 can receive user input by using various input devices, and the processor 110 can control the user equipment 100 based on the received user input. In addition, the user interface 140 can perform output based on a command from the processor 110 by using various output devices.

[0372] Next, the display unit 150 outputs various images on the display screen. The display unit 150 can output various display objects, such as content executed by the processor 110 or a user interface, based on a control command from the processor 110.

[0373] In addition, the base station 200 according to an embodiment of the present invention may include a processor 210, a communication module 220, and a memory 230.

[0374] First, the processor 210 can execute various commands or programs and process internal data of the base station 200. In addition, the processor 210 can control the overall operation of each unit including the base station 200 and control data transmission and reception between the units. In this case, the processor 210 can be configured to execute operations according to the embodiments described in the present invention. For example, the processor 210 can signal slot configuration information and perform communication according to the signaled slot configuration.

[0375] Next, the communication module 220 can be an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 120 can include multiple network interface cards in an internal or external form, such as cellular communication interface cards 221 and 222 and an unlicensed band communication interface card 223. Although the communication module 220 is illustrated as an integrated module in the drawings, different from the drawings, each network interface card can be independently arranged according to circuit configuration or purpose.

[0376] The cellular communication interface card 221 can transmit and receive wireless signals with at least one of the above-described user equipment 100, external equipment, and a server by using a mobile communication network, and can provide cellular communication services through a first band based on a command of the processor 210. According to an embodiment, the cellular communication interface card 221 can include at least one NIC module using a band below 6 GHz. At least one NIC module of the cellular communication interface card 221 can independently perform cellular communication with at least one of the user equipment 100, external equipment, and a server according to a cellular communication standard or protocol of the band below 6 GHz supported by the corresponding NIC module.

[0377] The cellular communication interface card 222 can transmit and receive wireless signals with at least one of the user equipment 100, external equipment, and a server by using a mobile communication network, and can provide cellular communication services through a second band based on a command of the processor 210. According to an embodiment, the cellular communication interface card 222 can include at least one NIC module using a band above 6 GHz. At least one NIC module of the cellular communication interface card 222 can independently perform cellular communication with at least one of the user equipment 100, external equipment, and a server according to a cellular communication standard or protocol of the band above 6 GHz supported by the corresponding NIC module.

[0378] The unauthorized band communication interface card 223 transmits and receives wireless signals with at least one of the user equipment 100, external equipment, and a server by using a third band as an unauthorized band, and provides an unauthorized band communication service based on a command of the processor 210. The unauthorized band communication interface card 223 may include at least one NIC module using an unauthorized band. For example, the unauthorized band may be a band of 2.4 GHz or 5 GHz. At least one NIC module of the unauthorized band communication interface card 223 may independently or dependently perform wireless communication with at least one of the user equipment 100, external equipment, and a server according to an unauthorized band communication standard or frequency protocol supported by the corresponding NIC module.

[0379] Figure 43 The user equipment 100 and the base station 200 illustrated in are block diagrams according to an embodiment of the present invention, and blocks shown separately represent logically different elements of the equipment. Therefore, according to the design of the equipment, the elements of the above equipment may be installed in one chip or multiple chips. In addition, some components of the user equipment 100, for example, the user interface 140, the display unit 150, etc., may be selectively provided in the user equipment 100. In addition, the user interface 140, the display unit 150, etc. may be additionally provided in the base station 200 as needed.

[0380] The foregoing description of the present invention is intended to be exemplary, and those skilled in the art will understand that the present invention can be easily modified in other specific forms without changing the technical idea and / or basic features of the present invention. Therefore, it should be understood that the above embodiments are exemplary in all aspects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

[0381] The scope of the present invention is shown by the appended claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims

1. A user equipment configured to operate in a wireless communication system, comprising: A communication module; And A processor configured to control the communication module, Wherein, the processor is configured to: Receive two or more downlink control information (DCI) from a base station, Wherein each of the two or more DCI is used to schedule physical downlink shared channel (PDSCH) reception on a corresponding cell among a plurality of cells, Wherein each of the plurality of cells is configured with transmission based on code block group (CBG) or transmission based on transport block (TB), and Wherein each of the two or more DCI includes either i) only a counter downlink allocation index (DAI), or ii) both the counter DAI and a total DAI, depending on the format, Identify TB-based PDSCH reception or CBG-based PDSCH reception on a corresponding cell among the plurality of cells based on the format of the DCI corresponding to the PDSCH among the two or more DCI, and Perform the CBG-based PDSCH reception and the TB-based PDSCH reception in the plurality of cells in which the two or more DCI are received, and Transmit a hybrid automatic repeat request acknowledgment (HARQ-ACK) codebook including a first HARQ-ACK sub-codebook for the TB-based PDSCH reception and a second HARQ-ACK sub-codebook for the CBG-based PDSCH reception, Wherein, according to the CBG-based PDSCH reception and the TB-based PDSCH reception, the counter DAI and the optional total DAI are individually applied to each of the first HARQ-ACK sub-codebook or the second HARQ-ACK sub-codebook.

2. The user equipment according to claim 1, Among them, The second HARQ-ACK sub-codebook is appended to the first HARQ-ACK sub-codebook, and Wherein, the counter DAI has a value associated with the cumulative number of downlink receptions scheduled for each corresponding PDSCH reception scheme.

3. The user equipment according to claim 1, Among them, The first HARQ-ACK sub-codebook includes one HARQ-ACK bit per transport block, Wherein, the second HARQ-ACK sub-codebook includes 'N' HARQ-ACK bits per transport block, and Wherein, 'N' is related to the number of CBGs configured for the user equipment.

4. The user equipment according to claim 3, Among them, When performing the CBG-based PDSCH reception in at least one cell among the plurality of cells, the second HARQ-ACK sub-codebook includes M HARQ-ACK bits and N - M NACK bits for the at least one cell, and the number of CBGs 'M' configured in the at least one cell is less than 'N'.

5. The user equipment according to claim 1, Among them, The counter DAI is used to identify the cumulative number of scheduled PDSCHs, and Wherein, the total DAI is used to identify the total number of scheduled PDSCHs.

6. A wireless communication method performed by a user equipment in a wireless communication system, comprising: Receiving two or more downlink control information (DCI) from a base station, Wherein each of the two or more DCI is used to schedule physical downlink shared channel (PDSCH) reception on a corresponding cell among a plurality of cells, Wherein each of the plurality of cells is configured with transmission based on code block group (CBG) or transmission based on transport block (TB), and Wherein each of the two or more DCI respectively includes, depending on the format, i) only a counter downlink allocation index (DAI), or ii) both the counter DAI and a total DAI, Identifying, based on the format of the DCI corresponding to the PDSCH among the two or more DCI, TB-based PDSCH reception or CBG-based PDSCH reception on a corresponding cell among the plurality of cells, and Performing the CBG-based PDSCH reception and the TB-based PDSCH reception in the plurality of cells in which the two or more DCI are received, and Transmitting a hybrid automatic repeat request acknowledgment (HARQ-ACK) codebook including a first HARQ-ACK sub-codebook for the TB-based PDSCH reception and a second HARQ-ACK sub-codebook for the CBG-based PDSCH reception, Wherein, according to the CBG-based PDSCH reception and the TB-based PDSCH reception, the counter DAI and the optional total DAI are separately applied to each of the first HARQ-ACK sub-codebook or the second HARQ-ACK sub-codebook.

7. The method according to claim 6, Among them, The second HARQ-ACK sub-codebook is appended to the first HARQ-ACK sub-codebook, and Wherein the counter DAI has a value associated with the cumulative number of downlink receptions scheduled for each corresponding PDSCH reception scheme.

8. The method according to claim 6, Among them, The first HARQ-ACK sub-codebook includes one HARQ-ACK bit for each transport block, Wherein the second HARQ-ACK sub-codebook includes 'N' HARQ-ACK bits for each transport block, and Wherein 'N' is related to the number of CBGs configured for the user equipment.

9. The method according to claim 8, Among them, When performing the CBG-based PDSCH reception in at least one cell among the plurality of cells, the second HARQ-ACK sub-codebook includes M HARQ-ACK bits and N-M NACK bits for the at least one cell, and the number 'M' of CBGs configured in the at least one cell is less than 'N'.

10. The method according to claim 6, Among them, The counter DAI is used to identify the cumulative number of scheduled PDSCHs, and Wherein, the total DAI is used to identify the total number of scheduled PDSCHs.

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