Terminal and wireless communication method

Abstract

To provide a terminal in a wireless communication system and a wireless communication method using the terminal.SOLUTION: In a wireless communication method, a processor of a terminal receives DCI in one or more cell(s) via a PDCCH indicating PDSCH scheduling information of each cell, identifies a transmission scheme in each cell based on a DCI format of the received DCI, receives a PDSCH of each cell in the one or more cell(s) based on the scheduling information of the PDCCH, generates a HARQ-ACK bit sequence for the one or more cell(s) in response to receiving the PDSCH of each cell based on the identified transmission scheme of each cell, and transmits the generated HARQ-ACK bit sequence.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a wireless communication system, and more particularly to a wireless communication method, apparatus and system for transmitting and receiving data and control channels. [Background technology]

[0002] Following the commercialization of 4G (4th generation) communication systems, efforts are being made to develop new 5G (5th generation) communication systems to meet the increasing demand for wireless data traffic. 5G communication systems are referred to as communication systems beyond 4G networks, post LTE systems, or new radio (NR) systems. In order to achieve high data transmission rates, 5G communication systems include systems operated using ultra-high frequency (mmWave) bands of 6 GHz or higher, and communication systems operated using frequency bands below 6 GHz are being considered for implementation in base stations and terminals in order to ensure coverage.

[0003] The 3GPP (registered trademark, hereinafter the same) (3rd generation partnership project) NR system improves the efficiency of network spectrum, allowing carriers to provide more data and voice services with a given bandwidth. Therefore, the 3GPP NR system is designed to meet the demand for high-speed data and media transmission in addition to supporting large capacity voice. The advantages of the NR system are that it has high throughput on the same platform, low latency, support for frequency division duplex (FDD) and time division duplex (TDD), improved end user environment, and low operating costs with a simple architecture.

[0004] For more efficient data processing, the dynamic TDD of the NR system uses a method of varying the number of orthogoal frequency division multiplexing (OFDM) symbols available for uplink and downlink depending on the data traffic direction of the user of the cell. For example, if the downlink traffic of a cell is greater than the uplink traffic, the base station allocates a number of downlink OFDM symbols to a slot (or subframe). Information about the slot configuration should be transmitted to the terminal.

[0005] In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, beamforming, massive array multiple input / output (massive MIMO), full dimension multiple input / output (FD-MIMO), array antenna, analog beam-forming, hybrid beamforming that combines analog beamforming and digital beamforming, and large scale antenna technologies are being discussed for the 5G communication system. In addition, to improve the system network, technological developments are being carried out in the 5G communication system regarding advanced small cells, improved 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), moving networks, cooperative communication, coordinated multi-points (CoMP), and interference cancellation.In addition, advanced coding modulation (ACM) methods such as hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), as well as advanced access technologies such as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) are being developed for 5G systems.

[0006] Meanwhile, the Internet is a human-centered network where humans generate and consume information, and is evolving into the Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. The Internet of Everything (IoE) technology is also emerging, which combines big data processing technology through connection with cloud servers with IoT technology. To realize IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, technologies such as sensor networks for connecting objects, machine to machine (M2M), and machine type communication (MTC) are being researched. In the IoT environment, intelligent IT (internet technology) services are provided that collect and analyze data generated from connected objects and create new value in human life. IoT is applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services through the fusion and integration of traditional IT (information technology) technology and various industries.

[0007] Therefore, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine, and MTC are being embodied by 5G communication technologies such as beamforming, MIMO, and array antennas. The application of cloud radio access network (cloud RAN), as the big data processing technology mentioned above, is also an example of the fusion of 5G technology and IoT technology. In general, mobile communication systems are being developed to provide voice services while ensuring user activity.

[0008] However, the mobile communication system has gradually expanded its scope from voice to data services, and is currently developed to provide high-speed data services. However, due to resource shortages in currently available mobile communication systems and users' demands for high-speed services, a more advanced mobile communication system is required. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2017 / 010764 [Non-patent literature]

[0010] [Non-Patent Document 1] NTT DOCOMO, INC.,HARQ-ACK multiplexing[online],3GPP TSG RAN WG1 adhoc_NR_AH_1706 R1-1711116,Internet<URL:http: / / www.3gpp.org / ftp / tsg_ran / WG1_RL1 / TSGR1_AH / NR_AH_1706 / Docs / R1-1711116.zip> ,June 30, 2017 [Non-Patent Document 2] Lenovo, Motorola Mobility,HARQ-ACK codebook design for CBG-based transmission[online],3GPP TSG RAN WG1 adhoc_NR_AH_1706 R1-1710605,Internet<URL:http: / / www.3gpp.org / ftp / tsg_ran / WG1_RL1 / TSGR1_AH / NR_AH_1706 / Docs / R1-1710605.zip> ,June 30, 2017 [Non-Patent Document 3] Fujitsu,Discussion on HARQ-ACK codebook[online],3GPP TSG RAN WG1 adhoc_NR_AH_1706 R1-1710242,Internet<URL:http: / / www.3gpp.org / ftp / tsg_ran / WG1_RL1 / TSGR1_AH / NR_AH_1706 / Docs / R1-1710242.zip> ,June 30, 2017 Summary of the Invention [Problem to be solved by the invention]

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

[0012] The present invention has an object to provide a method for generating a HARQ-ACK bit sequence when a terminal is configured to enable code block group (CBG)-based transmission.

[0013] Another object of the present invention is to provide a method for performing efficient retransmission when a terminal is configured to be capable of CBG-based transmission.

[0014] Furthermore, the present invention has an object to provide a method for generating a HARQ-ACK bit sequence when a terminal configured for CBG-based transmission fails to receive at least one PDCCH. [Means for solving the problem]

[0015] In order to solve the above problems, a terminal of a wireless communication system and a wireless communication method are provided as follows.

[0016] According to an embodiment of the present invention, a terminal of a wireless communication system includes a communication module and a processor for controlling the communication module, the processor receiving downlink control information (DCI) via a physical downlink control channel (PDCCH) indicating physical downlink shared channel (PDSCH) scheduling information of each cell from one or more cells, where at least one cell among the one or more cells is configured with code block group (CBG)-based transmission, identifying a transmission mode in each cell based on a DCI format of the DCI, where the transmission mode is one of transport block (TB)-based transmission and CBG-based transmission, receiving a PDSCH of each cell from the one or more cells based on the scheduling information of the PDCCH, and sending a hybrid automatic repeat request (HARQ) acknowledgement (ACK) to the one or more cells in response to the reception of the PDSCH of each cell. An HARQ-ACK bit sequence is generated based on the identified transmission method of each cell, and within the HARQ-ACK bit sequence, a HARQ-ACK bit sequence for TB-based transmission and a HARQ-ACK bit sequence for CBG-based transmission are generated separately, and a terminal is provided for transmitting the generated HARQ-ACK bit sequence.

[0017] According to an embodiment of the present invention, there is provided a wireless communication method in a wireless communication system, comprising the steps of: receiving downlink control information (DCI) via a physical downlink control channel (PDCCH) in one or more cells, the downlink control information indicating physical downlink shared channel (PDSCH) scheduling information of each cell; at least one cell among the one or more cells is configured for code block group (CBG)-based transmission; and identifying a transmission mode in each cell based on a DCI format of the DCI, the transmission mode being any one of transport block (TB)-based transmission and CBG-based transmission. receiving a PDSCH of each cell in the one or more cell(s) based on scheduling information of the PDCCH; generating a HARQ-ACK bit sequence for the one or more cell(s) based on an identified transmission scheme of each cell in response to receiving the PDSCH of each cell, wherein a HARQ-ACK bit sequence for a TB-based transmission and a HARQ-ACK bit sequence for a CBG-based transmission are separately generated within the HARQ-ACK bit sequence; and transmitting the generated HARQ-ACK bit sequence.

[0018] In the HARQ-ACK bit sequence for the TB-based transmission, one HARQ-ACK bit is generated per transmission block, and in the HARQ-ACK bit sequence for the CBG-based transmission, N HARQ-ACK bit(s) are generated per transmission block, where N is the maximum number of CBGs per transmission block configured in the terminal.

[0019] If the number M of CBG(s) transmitted through a specific cell in which CBG-based transmission is configured among the one or more cell(s) is less than N, the HARQ-ACK bit(s) for the specific cell consists of M HARQ-ACK bit(s) and NM NACK(s) for the transmitted CBG(s).

[0020] The processor receives a downlink allocation index (DAI) in the DCI format and generates the HARQ-ACK bit sequence by referring to the DAI, where the DAI includes a counter-DAI indicating the cumulative number of PDSCH(s) scheduled up to the current cell and a total-DAI indicating the total number of PDSCHs scheduled in all cells.

[0021] The DAI is applied separately to the HARQ-ACK bit sequence for the TB-based transmission and the HARQ-ACK bit sequence for the CBG-based transmission.

[0022] Within the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for the CBG-based transmission is appended next to the HARQ-ACK bit sequence for the TB-based transmission.

[0023] According to another embodiment of the present invention, a terminal of a wireless communication system includes a communication module and a processor for controlling the communication module, the processor receiving a Physical Downlink Control Channel (PDCCH) indicating Physical Downlink Shared Channel (PDSCH) scheduling information of each cell from one or more cells, at least one of the one or more cells being configured to be capable of code block group (CBG)-based transmission, receiving a downlink allocation index (DAI) via the PDCCH, and controlling the communication module for each cell of the one or more cells based on the scheduling information of the PDCCH. and generates a HARQ-ACK bit sequence for the one or more cell(s) by referring to the DAI in response to reception of the PDSCH of each cell, the HARQ-ACK bit sequence including at least one of a HARQ-ACK bit sequence for a transport block (TB)-based transmission and a HARQ-ACK bit sequence for a CBG-based transmission, the DAI being separately applied to the HARQ-ACK bit sequence for the TB-based transmission and the HARQ-ACK bit sequence for the CBG-based transmission, respectively, and a terminal transmitting the generated HARQ-ACK bit sequence is provided.

[0024] According to another embodiment of the present invention, there is provided a wireless communication method in a wireless communication system, comprising the steps of: receiving, in one or more cells, a physical downlink control channel (PDCCH) indicating physical downlink shared channel (PDSCH) scheduling information of each cell, at least one of the one or more cells being configured to enable code block group (CBG)-based transmission; receiving a downlink allocation index (DAI) via the PDCCH; receiving, in the one or more cells, a PDSCH of each cell based on the scheduling information of the PDCCH; and, upon receiving the PDSCH of each cell, generating a HARQ-ACK bit sequence for the one or more cell(s) in response to the DAI, the HARQ-ACK bit sequence including at least one of a HARQ-ACK bit sequence for a transport block (TB)-based transmission and a HARQ-ACK bit sequence for a CBG-based transmission, the DAI being separately applied to the HARQ-ACK bit sequence for the TB-based transmission and the HARQ-ACK bit sequence for the CBG-based transmission, respectively; and transmitting the generated HARQ-ACK bit sequence.

[0025] The HARQ-ACK bit sequence is generated based on the identified transmission mode of each cell, where the transmission mode in each cell is either TB-based transmission or CBG-based transmission.

[0026] The processor receives downlink control information (DCI) via the PDCCH, and the transmission scheme of each cell is identified based on a DCI format of the DCI.

[0027] In the HARQ-ACK bit sequence for the TB-based transmission, one HARQ-ACK bit is generated per transmission block, and in the HARQ-ACK bit sequence for the CBG-based transmission, N HARQ-ACK bit(s) are generated per transmission block, where N is the maximum number of CBGs per transmission block configured in the terminal.

[0028] If the number M of CBG(s) transmitted through a specific cell in which CBG-based transmission is configured among the one or more cell(s) is less than N, the HARQ-ACK bit(s) for the specific cell consists of M HARQ-ACK bit(s) and NM NACK(s) for the transmitted CBG(s).

[0029] Within the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for the CBG-based transmission is appended next to the HARQ-ACK bit sequence for the TB-based transmission.

[0030] The DAI applied to the TB-based transmission includes a counter-DAI indicating the cumulative number of TB-based PDSCH(s) scheduled up to the current cell and a total-DAI indicating the total number of TB-based PDSCH(s) scheduled in all cells, and the DAI applied to the CBG-based transmission includes a counter-DAI indicating the cumulative number of CBG-based PDSCH(s) scheduled up to the current cell and a total-DAI indicating the total number of CBG-based PDSCH(s) scheduled in all cells.

[0031] If the Total-DAI of the DAI applied to the TB-based transmission indicates a preset value and no PDCCH scheduling the TB-based transmission is received, the HARQ-ACK bit sequence is constructed excluding the HARQ-ACK bit sequence for the TB-based transmission, and if the Total-DAI of the DAI applied to the CBG-based transmission indicates a preset value and no PDCCH scheduling the CBG-based transmission is received, the HARQ-ACK bit sequence is constructed excluding the HARQ-ACK bit sequence for the CBG-based transmission.

[0032] The preset value is the binary number "11".

[0033] The HARQ-ACK bit sequence is transmitted over a Physical Uplink Shared Channel (PUSCH). Effect of the Invention

[0034] According to an embodiment of the present invention, it is possible to minimize the overhead of downlink control information for a terminal configured to be capable of CBG-based transmission to refer to in determining a HARQ-ACK bit sequence, thereby increasing the network transmission efficiency between a base station and a terminal.

[0035] Furthermore, according to an embodiment of the present invention, the signaling overhead for requesting retransmission can be minimized through efficient signaling of the fallback mode.

[0036] The effects obtained by the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief description of the drawings]

[0037] [Figure 1] FIG. 2 is a diagram illustrating an example of a radio frame structure used in a wireless communication system. [Diagram 2] FIG. 1 is a diagram illustrating an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. [Diagram 3] 1 is a diagram for explaining physical channels used in the 3GPP system and a general signal transmission method using the corresponding physical channels. [Figure 4] A diagram showing SS / PBCH blocks for initial cell access in a 3GPP NR system. [Diagram 5] A diagram showing a procedure for control information and control channel transmission in a 3GPP NR system. [Figure 6] FIG. 1 is a diagram showing a control resource set (CORESET) in which a physical downlink control channel (PDCCH) is transmitted in a 3GPP NR system. [Figure 7] A diagram showing a method for setting a PDCCH search space in a 3GPP NR system. [Figure 8] FIG. 1 is a conceptual diagram illustrating carrier aggregation. [Figure 9] FIG. 1 is a diagram for explaining single carrier communication and multi-carrier communication. [Figure 10] A diagram showing an example in which a cross-carrier scheduling technique is applied. [Figure 11] 2 is a diagram illustrating a code block group (CBG) configuration and its time-frequency resource mapping according to an embodiment of the present invention. FIG. [Figure 12] 1 is a diagram showing a process in which a base station performs TB-based transmission or CBG-based transmission and a terminal transmits a HARQ-ACK in response thereto according to an embodiment of the present invention. [Figure 13] A diagram illustrating one embodiment of a method for interpreting received HARQ-ACK feedback and fallback indicators. [Figure 14]A diagram showing another embodiment of a method for interpreting received HARQ-ACK feedback and fallback indicators. [Figure 15] 1 is a diagram illustrating an example in which a terminal transmits a HARQ-ACK and a fallback indicator to a CBG(s) according to the above-described embodiment. [Figure 16] A diagram showing an additional embodiment in which the terminal transmits a HARQ-ACK and a fallback indicator to the CBG(s). [Figure 17] A diagram showing an additional embodiment in which the terminal transmits a HARQ-ACK and a fallback indicator to the CBG(s). [Figure 18] A diagram showing an additional embodiment in which the terminal transmits a HARQ-ACK and a fallback indicator to the CBG(s). [Figure 19] A diagram showing an additional embodiment in which the terminal transmits a HARQ-ACK and a fallback indicator to the CBG(s). [Figure 20] FIG. 1 is a diagram illustrating an example of a downlink assignment index (DAI) value mapped to each component carrier. [Figure 21] FIG. 2 is a diagram illustrating a DAI signaling method and a HARQ-ACK bit sequence generation method based on the DAI signaling method according to a first embodiment of the present invention. [Figure 22] FIG. 2 is a diagram illustrating a DAI signaling method and a HARQ-ACK bit sequence generation method based on the DAI signaling method according to a first embodiment of the present invention. [Diagram 23] FIG. 11 illustrates a DAI signaling method according to a second embodiment of the present invention. [Figure 24] FIG. 11 is a diagram showing a DAI signaling method according to a third embodiment of the present invention. [Diagram 25] FIG. 11 illustrates an embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled according to the third embodiment described above. [Figure 26] FIG. 11 illustrates an embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled according to the third embodiment described above. [Figure 27] FIG. 11 is a diagram showing another embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled by the third embodiment described above. [Figure 28] A diagram showing a DAI signaling method according to a fourth embodiment of the present invention. [Figure 29] A diagram showing a DAI signaling method according to a fifth embodiment of the present invention. [Diagram 30] A diagram showing a DAI signaling method according to a sixth embodiment of the present invention. [Diagram 31] A figure showing an embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled by the sixth embodiment described above. [Diagram 32] A diagram showing a DAI signaling method according to a seventh embodiment of the present invention. [Diagram 33] FIG. 13 is a diagram showing an embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled according to the seventh embodiment described above. [Diagram 34] A diagram showing a DAI signaling method according to an eighth embodiment of the present invention. [Diagram 35] A diagram showing a DAI signaling method according to a ninth embodiment of the present invention. [Diagram 36] FIG. 13 is a diagram showing an embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled according to the above-mentioned ninth embodiment. [Figure 37] A figure showing a DAI signaling method according to a 10th embodiment of the present invention. [Figure 38] A diagram showing a compression method of HARQ-ACK according to an embodiment of the present invention. [Figure 39] A diagram showing a method for performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. [Diagram 40] A diagram showing a method for performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. [Diagram 41]A diagram showing in more detail a method for performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. [Diagram 42] A diagram showing in more detail a method for performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. [Diagram 43] 2 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] The terms used in this specification are selected from currently widely used general terms as much as possible while taking into consideration the functions in the present invention, but this may vary depending on the intentions of the engineers in this field, customs, or the emergence of new technologies. In addition, in certain cases, the applicant may arbitrarily select terms, and in this case, the meanings of the terms will be described in the corresponding embodiment of the invention. Therefore, it is made clear that the terms used in this specification should be interpreted based on the substantial meanings of the terms and the contents of this specification as a whole, rather than simply the names of the terms.

[0039] Throughout the specification, when a certain component is "connected" to another component, this includes not only when it is "adjustably connected" to another component, but also when it is "electrically connected" with another component in between. Furthermore, when a certain component is said to "include" a particular component, this does not mean to exclude the other component, but to further include the other component, unless otherwise specified to the contrary. In addition, limitations such as "greater than" or "less than" based on a particular critical value may be appropriately switched to "greater than" or "less than", respectively, depending on the embodiment.

[0040] The following technologies are 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 frequency division multiple access (SC-FDMA), etc. CDMA is implemented in radio technologies such as universal terrestrial radio access (UTRA) and CDMA2000. TDMA is implemented in radio technologies such as global system for mobile communications (GSM), general packet radio service (GPRS), and enhanced data rates for GSM evolution (EDGE). OFDMA is implemented in radio 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 a part of the universal mobile telecommunications system (UMTS). 3GPP LTE (long term evolution) is a part of E-UMTS (evolved UMTS) that uses E-UTRA, and LTE-A (LTE-advanced) is an evolved version of 3GPP LTE. It is a system designed separately from 3GPP NR LTE / LTE-A, and is a system to support eMBB (enhanced BroadBand), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive Machine Type Communication) services, which are requirements of IMT-2020.For clarity of explanation, the following description will focus on 3GPP NR, but the technical idea of ​​the present invention is not limited thereto.

[0041] In this specification, unless otherwise specified, a base station includes a gNB (next generation node B) defined in 3GPP NR. Also, unless otherwise specified, a terminal is referred to as a UE (user equipment).

[0042] FIG. 1 is a diagram showing an example of a radio frame structure used in a wireless communication system. Referring to FIG. 1, a radio frame used in a 3GPP NR system has a period of 10 ms (Δf max N f / 100)*T c ) and the radio frame consists of 10 equally sized subframes (SF). Here, Δf max =480*10 3 Hz, N f =4096, T c =1 / (Δf max *N f,ref ), Δf ref =15*10 3 Hz, N f,ref = 2048. The 10 subframes in one frame are numbered from 0 to 9. Each subframe has a length of 1 ms and consists of one or more slots depending on the subcarrier spacing. More specifically, the subcarrier spacing that can be used in the 3GPP NR system is 15*2 μ kHz. μ is the subcarrier spacing configuration, and μ has a value of 0 to 4. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 240 kHz is used as the subcarrier spacing. A subframe of 1 ms length is 2 μ Each slot has a length of 2 -μ ms. μ The slots range from 0 to 2μ The slots in a radio frame are numbered from 0 to 10*2. μ The time resources are assigned numbers up to -1. The time resources are divided by at least one of a radio frame number (also called a radio frame index), a subframe number (also called a subframe index), and a slot number (or a slot index).

[0043] FIG. 2 illustrates an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, FIG. 2 illustrates a resource grid structure of a 3GPP NR system. There is one resource grid per antenna port. Referring to FIG. 2, a slot includes a plurality of OFDM symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. An OFDM symbol may also mean one symbol period. Unless otherwise specified, an OFDM symbol is simply referred to as a symbol. Referring to FIG. 2, a signal transmitted from each slot is N size、μ grid、x *N RB SC subcarriers and N slot symb It is represented by a resource lattice consisting of OFDM symbols, where x=DL for the downlink resource lattice and x=UL for the uplink resource lattice. size、μ grid、x indicates the number of resource blocks (RBs) according to the subcarrier spacing factor μ (x is DL or UL), and N slot symb N denotes the number of OFDM symbols in a slot. RB SC is the number of subcarriers that make up one RB, and N RB SC= 12. Depending on the multiple access method, the OFDM symbol is called a cyclic prefix OFDM symbol (CP-OFDM) symbol or a discrete Fourier transform spread OFDM symbol (DFT-S-OFDM).

[0044] The number of OFDM symbols included in one slot may vary depending on the length of the cyclic prefix (CP). For example, if a normal CP is used, one slot includes 14 OFDM symbols, whereas if an extended CP is used, one slot includes 12 OFDM symbols. In a specific embodiment, the extended CP is used only with a subcarrier spacing of 60 kHz. For convenience of explanation, FIG. 2 illustrates a case where one slot includes 14 OFDM symbols, but the embodiment of the present invention is also applicable in the same manner to slots having other numbers of OFDM symbols. Referring to FIG. 2, each OFDM symbol is represented by N size、μ grid、x *N RB SC It includes subcarriers. The subcarriers are classified into data subcarriers for transmitting data, reference signal subcarriers for transmitting reference signals, and guard bands. The carrier frequency is also called the center frequency (fc).

[0045] One RB is N RB SC A RB is defined as N (e.g., 12) consecutive subcarriers. Incidentally, a resource consisting of one OFDM symbol and one subcarrier is called a resource element (RE) or tone. Therefore, one RB is N slot symb *N RB SC Each resource element in the resource lattice is uniquely defined by an index pair (k, l) within one slot, where k runs from 0 to N in the frequency domain. size、μgrid、x *N RB SC An index given from -1 to N, where 1 is the time domain from 0 to N slot symb This is an index up to -1.

[0046] In order for a terminal to receive a signal from a base station or transmit a signal to a base station, the time / frequency synchronization of the terminal should be aligned with the time / frequency synchronization of the base station, because if the base station and the terminal are not synchronized, the terminal cannot determine the time and frequency parameters required to demodulate DL signals and transmit UL signals at the correct time.

[0047] Each symbol of a radio frame operating in time division duplex (TDD) or unpaired spectrum consists of at least one of downlink symbol (DL symbol), uplink symbol (UL symbol) or flexible symbol. A radio frame operating in frequency division duplex (FDD) or paired spectrum with a downlink carrier consists of downlink symbols or flexible symbols, and a radio frame operating with an uplink carrier consists of uplink symbols or flexible symbols. A downlink symbol allows downlink transmission but not uplink transmission, and an uplink symbol allows uplink transmission but not downlink transmission. Whether a flexible symbol is used in the downlink or uplink is determined depending on the signal.

[0048] Information regarding the type of each symbol, that is, information indicating any one of a downlink symbol, an uplink symbol, and a flexible symbol, consists of a cell-specific (or common) radio resource control (RRC) signal. Further, information regarding the type of each symbol consists of an additional UE-specific (or dedicated) RRC signal. The base station uses the cell-specific RRC signal to notify (i) the period of the cell-specific slot configuration, (ii) the number of slots having only downlink symbols from the beginning of the period of the cell-specific slot configuration, (iii) the number of downlink symbols from the first symbol of the slot immediately following the slot having only downlink symbols, (iv) the number of slots having only uplink symbols from the end of the period of the cell-specific slot configuration, and (v) the number of uplink symbols from the last symbol of the slot immediately preceding the slot having only uplink symbols. Here, a symbol not composed of either an uplink symbol or a downlink symbol is a flexible symbol.

[0049] If the information regarding the symbol type consists of a UE-specific RRC signal, the base station signals whether the flexible symbol is a downlink symbol or an uplink symbol by using the cell-specific RRC signal. At this time, the UE-specific RRC signal cannot change a downlink symbol or an uplink symbol consisting of the cell-specific RRC signal to another symbol type. The UE-specific RRC signal signals, for each slot, the number of downlink symbols among the N symbols of the corresponding slot and the number of uplink symbols among the N symbols of the corresponding slot. At this time, the downlink symbols of the slot are continuously configured from the first symbol to the i-th symbol of the slot. Further, the uplink symbols of the slot are continuously configured from the j-th symbol to the last symbol of the slot (where i < j). In a slot, a symbol not composed of either an uplink symbol or a downlink symbol is a flexible symbol. slot symb symbols of the slot and the number of uplink symbols among the N slot symb symbols of the slot. At this time, the downlink symbols of the slot are continuously configured from the first symbol to the i-th symbol of the slot. Further, the uplink symbols of the slot are continuously configured from the j-th symbol to the last symbol of the slot (where i < j). In a slot, a symbol not composed of either an uplink symbol or a downlink symbol is a flexible symbol.

[0050] The type of symbols consisting of the RRC signal is called a semi-static DL / UL configuration. In the semi-static DL / UL configuration consisting of the RRC signal, the flexible symbol is designated as a downlink symbol, an uplink symbol, or a flexible symbol through dynamic slot format information (SFI) transmitted on a physical downlink control channel (PDCCH). In this case, the downlink symbol or the uplink symbol consisting of the RRC signal is not changed to another symbol type. Table 1 shows an example of dynamic SFI designated by the base station to the terminal.

[0051] [Table 1]

[0052] In Table 1, D indicates a downlink symbol, U indicates an uplink symbol, and X indicates a flexible symbol. As shown in Table 1, up to two DL / UL switchings are allowed in one slot.

[0053] FIG. 3 is a diagram explaining physical channels used in a 3GPP system (e.g., NR) and a general signal transmission method using the physical channels. When a terminal is turned on or enters a new cell, the terminal performs an initial cell search operation S101. More specifically, the terminal synchronizes with a base station in the initial cell search. To this end, the terminal receives a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station and acquire information such as a cell ID. Next, the terminal receives a physical broadcast channel from the base station to acquire broadcast information within the cell.

[0054] After the terminal has finished its initial state, the terminal receives a physical downlink shared channel (PDSCH) via a physical downlink control channel (PDCCH) and information carried on the PDCCH, thereby acquiring more detailed system information than the system information acquired via the initial cell terminal (S102).

[0055] When the terminal first accesses the base station or there is no radio resource for transmitting a signal, the terminal performs a random access procedure to the base station (S103 to S106). First, the terminal transmits a preamble via a physical random access channel (PRACH) (S103) and receives a response message to the preamble from the base station via a PDCCH and a corresponding PDSCH (S104). If the terminal receives a valid random access response message, the terminal transmits data including its own identifier, etc. to the base station via a physical uplink shared channel (PUSCH) indicated from an uplink grant transmitted from the base station via the PDCCH (S105). Next, the terminal waits to receive a PDCCH as an instruction from the base station to resolve collisions. If the terminal successfully receives the PDCCH via its own identifier (S106), the random access procedure is terminated.

[0056] After the above-mentioned procedure, the terminal receives PDCCH / PDSCH S107 and transmits physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) S108 as a general uplink / downlink signal transmission procedure. In particular, the terminal receives downlink control information (DCI) via the PDCCH. The DCI includes control information such as resource allocation information for the terminal. The format of the DCI may differ depending on the purpose of use. The uplink control information (UCI) transmitted by the terminal to the base station via the uplink includes downlink / uplink ACK / NACK signals, a channel quality indicator (CQI), a precoding matrix index (PMI), an RNAK indicator (RI), etc. Here, the CQI, PMI, and RI are included in channel state information (CSI). In the case of a 3GPP NR system, the terminal transmits control information such as the above-mentioned HARQ-ACK and CSI via the PUSCH and / or PUCCH.

[0057] FIG. 4 is a diagram showing an SS / PBCH block for initial cell access in a 3GPP NR system. When a terminal is powered on or attempts to access a new cell, the terminal acquires time and frequency synchronization with the cell and performs an initial cell search process. In the cell search process, the terminal obtains a physical cell identity N cell ID To this end, the terminal receives synchronization signals, such as a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), from the base station to synchronize with the base station. At this time, the terminal obtains information such as a cell identity (ID).

[0058] With reference to FIG. 4(a), the synchronization signal (SS) will be described in more detail. The synchronization signal is divided into PSS and SSS. The PSS is used to obtain time domain synchronization and / or frequency domain synchronization such as OFDM symbol synchronization and slot synchronization. The SSS is used to obtain frame synchronization and cell group ID. With reference to FIG. 4(a) and Table 2, the SS / PBCH block consists of 20 consecutive RBs (=240 subcarriers) on the frequency axis and 4 consecutive OFDM symbols on the time axis. In this case, in the SS / PBCH block, the PSS is transmitted in the first OFDM symbol and the SSS is transmitted in the third OFDM symbol via the 56th to 182nd subcarriers. Here, the lowest subcarrier index of the SS / PBCH block is numbered starting from 0. In the first OFDM symbol in which the PSS is transmitted, the base station does not transmit signals via the remaining subcarriers, i.e., the 0th to 55th and 183rd to 239th subcarriers. In addition, in the third OFDM symbol in which the SSS is transmitted, the base station does not transmit signals via subcarriers 48 to 55 and 183 to 191. The base station transmits a physical broadcast channel (PBCH) via the remaining REs in the SS / PBCH block excluding the above-mentioned signals.

[0059] [Table 2]

[0060] The SS is grouped into 336 physical-layer cell-id groups, each of which contains 3 unique identifiers, so that each physical-layer cell-id is part of only one physical-layer cell-id group, with the total of 1008 unique physical-layer cell-ids being generated through the combination of the three PSSs and SSSs. cell ID =3N (1) ID +N (2) IDis an index N in the range from 9 to 335 that indicates a physical-layer cell-identifier group. (1) ID and an index N from 0 to 2 indicating a physical-layer identifier within the physical-layer cell-identifier group. (2) ID The UE detects the PSS and identifies one of three unique physical-layer identifiers. The UE also detects the SSS and identifies one of 336 physical layer cell IDs associated with the physical-layer identifier. In this case, the sequence d of the PSS PSS (n) is as follows:

[0061]

number

[0062] Where:

number

number

[0063] Also, the sequence of SSS SSS (n) is as follows:

number

[0064] Where:

number

number

[0065] A radio frame with a length of 10 ms is divided into two half frames with a length of 5 ms. The slots in each half frame in which the SS / PBCH block is transmitted will be described with reference to FIG. 4(b). The slots in which the SS / PBCH block is transmitted are any one of cases A, B, C, D, and E. In case A, the subcarrier spacing is 15 kHz, and the start point of the SS / PBCH block is the {2, 8}+14*nth symbol. In this case, n=0, 1 for carrier frequencies below 3 GHz. Also, n=0, 1, 2, 3 for carrier frequencies above 3 GHz and below 6 GHz. In case B, the subcarrier spacing is 30 kHz, and the start point of the SS / PBCH block is the {4, 8, 16, 20}+28*nth symbol. In this case, n=0 for carrier frequencies below 3 GHz. Also, n=0, 1 for carrier frequencies above 3 GHz and below 6 GHz. In case C, the subcarrier spacing is 30 kHz and the start of the SS / PBCH block is {2, 8}+14*n symbols, where n=0, 1 for carrier frequencies below 3 GHz. Also, n=0, 1, 2, 3 for carrier frequencies above 3 GHz and below 6 GHz. In case D, the subcarrier spacing is 120 kHz and the start of the SS / PBCH block is {4, 8, 16, 20}+28*n symbols, where n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18 for carrier frequencies above 6 GHz. In case E, the subcarrier spacing is 240 kHz and the start of the SS / PBCH block is {8, 12, 16, 20, 32, 36, 40, 44}+56*n symbols. In this case, n=0, 1, 2, 3, 5, 6, 7, 8 for carrier frequencies of 6 GHz or higher.

[0066] FIG. 5 is a diagram showing a procedure for transmitting control information and a control channel in a 3GPP NR system. Referring to FIG. 5(a), a base station adds a cyclic redundancy check (CRC) masked (e.g., XORed) with a radio network temporary iedntifier (RNTI) to control information (e.g., DCI) S202. The base station scrambles the CRC with an RNTI value determined according to the purpose / target of each control information. The common RNTI used by one or more terminals includes at least one of a system information RNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI), and a traffic power control RNTI (TPC-RNTI). Also, the terminal-specific RNTI includes at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Next, the base station performs channel encoding (e.g., polar coding) S204, and then performs rate-matching according to the amount of resource(s) used for PDCCH transmission S206. Next, the base station multiplexes DCI(s) based on a PDCCH structure based on CCE (control channel element) S208. The base station also applies additional processes S210, such as scrambling, modulation (e.g., QPSK), and interleaving, to the multiplexed DCI(s), and maps it to resources to be transmitted. A CCE is a basic unit for PDCCH, and one CCE consists of a plurality of (e.g., 6) resource element groups (REGs). One REG consists of a plurality of (e.g., 12) REs. The number of CCEs used for one PDCCH is defined as an aggregation level. In the 3GPP NR system, aggregation levels of 1, 2, 4, 8, or 16 are used. FIG. 5(b) is a diagram relating to CCE aggregation levels and PDCCH multiplexing, showing the types of CCE aggregation levels used for one PDCCH and the CCE(s) transmitted in the control region accordingly.

[0067] FIG. 6 is a diagram showing a control resource set (CORESET) on which a physical downlink control channel (PDCCH) in a 3GPP NR system is transmitted. The CORESET is a time-frequency resource on which a PDCCH, which is a control signal for a terminal, is transmitted. In addition, a search space, which will be described later, is mapped to one CORESET. Therefore, the terminal does not monitor all frequency bands to receive the PDCCH, but monitors a time-frequency region designated as the CORESET and decodes the PDCCH mapped to the CORESET. The base station configures one or more CORESETs for each cell in the terminal. The CORESET is made up of up to three consecutive symbols on the time axis. In addition, the CORESET is made up of six units of consecutive PRBs on the frequency axis. In the embodiment of FIG. 5, the CORESET#1 is made up of consecutive PRBs, and the CORESET#2 and CORESET#3 are made up of non-consecutive PRBs. The CORESET may be located at any symbol in a slot. For example, in the embodiment of FIG. 5, CORESET#1 begins at the first symbol of the slot, CORESET#2 begins at the fifth symbol of the slot, and CORESET#9 begins at the ninth symbol of the slot.

[0068] FIG. 7 is a diagram illustrating a method of setting a PDCCH search space in a 3GPP NR system. In order to transmit a PDCCH to a terminal, at least one search space exists in each CORESET. In an embodiment of the present invention, the search space is a set of all time-frequency resources (hereinafter, PDCCH candidates) in which the PDCCH of the terminal is transmitted. The search space includes a common search space that 3GPP NR terminals should commonly search, and a terminal-specific or UE-specific search space that a specific terminal should search. In the common search space, all terminals in a cell belonging to the same base station monitor a PDCCH that is set to be commonly searched. In addition, the terminal-specific search space is set for each terminal so that the PDCCH allocated to each terminal is monitored at a position of the search space that differs from one another according to the terminal. In the case of the terminal-specific search space, the search spaces between terminals may be partially overlapped due to the limited control region to which the PDCCH is allocated. Monitoring the PDCCH includes blind decoding the PDCCH candidates in the search space. If blind decoding is successful, it is expressed as the PDCCH being (successfully) detected / received, and if blind decoding is unsuccessful, it is expressed as the PDCCH being undetected / not received or not successfully detected / received.

[0069] For convenience of explanation, a PDCCH scrambled with a group common (GC) RNTI that a terminal already knows in order to transmit downlink control information to one or more terminals is referred to as a group common (GC) PDCCH or a common PDCCH. Also, a PDCCH scrambled with a terminal-specific RNTI that a specific terminal already knows in order to transmit uplink scheduling information or downlink scheduling information to one specific terminal is referred to as a terminal-specific PDCCH. The common PDCCH is included in a common search space, and the terminal-specific PDCCH is included in a common search space or a terminal-specific PDCCH.

[0070] A base station notifies a terminal or a terminal group of information on resource allocation of transmission channels PCH (paging channel) and DL-SCH (downlink-shared channel) (i.e., DL Grant) or information on UL-SCH resource allocation and hybrid automatic repeat request (HARQ) (i.e., UL Grant) via a PDCCH. The base station transmits a PCH transport block and a DL-SCH transport block via a PDSCH. The base station transmits data excluding specific control information or specific service data via the PDSCH. In addition, a terminal receives data excluding specific control information or specific service data via the PDSCH.

[0071] The base station transmits information on which terminal (one or more terminals) the PDSCH data is transmitted to and how the corresponding terminal should receive and decode the PDSCH data by including it in the PDCCH. For example, assume that the DCI transmitted to a specific PDCCH is CRC masked to an RNTI of "A", the DCI indicates that the PDSCH is allocated to a radio resource (e.g., a frequency position) of "B", and indicates transmission format information (e.g., a transmission block size, a modulation method, coding information, etc.) of "C". The terminal monitors the PDCCH using its own RNTI information. In this case, if there is a terminal that blind decodes the PDCCH with RNTI "A", the corresponding terminal receives the PDCCH and receives the PDSCH indicated by "B" and "C" through the received PDCCH information.

[0072] Table 3 shows an example of a physical uplink control channel (PUCCH) used in a wireless communication system.

[0073] [Table 3]

[0074] The PUCCH is used to transmit the following uplink control information (UCI):

[0075] -SR (scheduling request): Information used to request uplink UL-SCH resources.

[0076] -HARQ-ACK: a response to a PDCCH (indicating DL SPS release) and / or a response to an uplink transport block (TB) on a PDSCH. HARQ-ACK indicates whether information transmitted via a PDCCH or a PDSCH has been received. HARQ-ACK responses include positive ACK (simply, ACK), negative ACK (hereinafter, NACK), discontinuous transmission (DTX), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK / NACK and ACK / NACK. In general, ACK is represented by a bit value of 1 and NACK is represented by a bit value of 0.

[0077] -CSI: Feedback information for a downlink channel. It is generated by a terminal based on a CSI-RS (reference signal) transmitted by a base station. MIMO (multiple input multiple output)-related feedback information includes RI and PMI. CSI is divided into CSI part 1 and CSI part 2 according to the information indicated by CSI.

[0078] In the 3GPP NR system, five PUCCH formats are used to support various service scenarios and various channel environments and frame structures.

[0079] PUCCH format 0 is a format that carries 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 is transmitted through one or two OFDM symbols on the time axis and one RB on the frequency axis. If PUCCH format 0 is transmitted through two OFDM symbols, the same sequence is transmitted in two symbols in different RBs. Through this, the terminal obtains frequency diversity gain. More specifically, the terminal bit Bit UCI(M bit =1 or 2), the cyclic shift value m cs Determine the base sequence of length 12 and divide it by the determined value m cs The sequence cyclically shifted by M is mapped to 12 REs of one OFDM symbol and one PRB and transmitted. The number of cyclic shifts available to the terminal is 12, and M bit If =1, then 1-bit UCI0 and 1 are represented by a sequence of two cyclic shifts whose difference in cyclic shift value is 6. Also, M bit = 2, then the 2-bit UCI 00, 01, 11, 10 is represented by a sequence of four cyclic shifts with a cyclic shift value difference of 3.

[0080] PUCCH format 1 carries 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 is transmitted through continuous OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 is one of 4 to 14. bit The UCI, where M = 1, is modulated by BPSK. bitThe UCI, where d(0) is a 12-bit number, is modulated with quadrature phase shift keying (QPSK). A signal is obtained by multiplying the modulated complex valued symbol d(0) with a sequence of length 12. The terminal transmits the obtained signal by spreading it with a time-domain orthogonal cover code (OCC) on the even-numbered OFDM symbol to which PUCCH format 1 is assigned. In PUCCH format 1, the maximum number of different terminals that can be multiplexed in the same RB is determined according to the length of the OCC used. A demodulation reference signal (DMRS) is mapped to odd-numbered OFDM symbols in PUCCH format 1 by spreading it with OCC.

[0081] PUCCH format 2 carries UCI exceeding 2 bits. PUCCH format 2 is transmitted through one or two OFDM symbols in the time axis and one or more RBs in the frequency axis. If PUCCH format 2 is transmitted through two OFDM symbols, the same sequence is transmitted through two OFDM symbols in different RBs. Through this, the UE obtains frequency diversity gain. For more details, see M bit Bit UCI(M bit >2) is bit-level scrambled, QPSK modulated, and mapped to the RBs of one or two OFDM symbol(s), where the number of RBs is one from 1 to 16.

[0082] PUCCH format 3 or PUCCH format 4 carries UCI exceeding 2 bits. PUCCH format 3 or PUCCH format 4 is transmitted through continuous OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 is one of 4 to 14. bit Bit UCI(M bit>2) is modulated with π / 2-BPSK (Binary Phase Shift Keying) or QPSK to generate complex symbols d(0) to d(M symb -1), where M symb =M bit When QPSK is used, symb =M bit / 2. The terminal does not apply block-wise spreading to PUCCH format 3. However, the terminal may apply block-wise spreading to one RB (i.e., 12 subcarriers) using PreDFT-OCC of length-12 so that PUCCH format 4 has a multiplexing capacity of two or four. The terminal transmits the spread signal by transmit precoding (or DFT-precoding), mapping it to each RE, and transmitting the spread signal.

[0083] In this case, the number of RBs indicated by PUCCH format 2, PUCCH format 3, or PUCCH format 4 is determined according to the length of UCI transmitted by the terminal and the maximum code rate. If the terminal uses PUCCH format 2, the terminal transmits both HARQ-ACK information and CSI information via PUCCH. If the number of RBs that the terminal can transmit is greater than the maximum number of RBs that PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the terminal does not transmit some UCI information according to the priority of the UCI information, and transmits only the remaining UCI information.

[0084] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured via RRC signaling to indicate frequency hopping within a slot. When frequency hopping is configured, the index of the RB to be frequency hopped is configured via RRC signaling. If PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted over N OFDM symbols on the time axis, the first hop has floor(N / 2) OFDM symbols and the second hop has ceil(N / 2) OFDM symbols.

[0085] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured to be repeatedly transmitted in multiple slots. In this case, the number K of slots in which the PUCCH is repeatedly transmitted is configured by an RRC signal. The repeatedly transmitted PUCCH should start from the same OFDM symbol position in each slot and have the same length. If the RRC signal indicates that any one of the OFDM symbols in the slot in which the UE should transmit the PUCCH is a DL symbol, the UE does not transmit the PUCCH from the corresponding slot, but postpones it to the next slot for transmission.

[0086] Meanwhile, in a 3GPP NR system, a terminal transmits and receives using a bandwidth smaller than or equal to the bandwidth of a carrier (or cell). To this end, the terminal is configured with a BWP (bandwidth part) consisting of a continuous bandwidth that is a part of the carrier bandwidth. A terminal operating according to TDD or in an unpaired spectrum is configured with up to four DL / UL BWP pairs for one carrier (or cell). The terminal also activates one DL / UL BWP pair. A terminal operating according to FDD or in a paired spectrum is configured with up to four DL BWPs for a downlink carrier (or cell) and up to four UL BWPs for an uplink carrier (or cell). The terminal activates one DL BWP and one UL BWP for each carrier (or cell). The terminal may not receive or transmit from time-frequency resources other than the activated BWP. The activated BWP is called an active BWP.

[0087] The base station refers to the BWP that is configured among the BWPs configured for the terminal as a DCI. The BWP indicated by the DCI is activated, and the other configured BWP(s) is deactivated. In a carrier (or cell) operating in TDD, the base station includes a BPI (bandwidth part indicator) indicating the activated BWP in the DCI for scheduling the PDSCH or PUSCH to change the DL / UL BWP pair of the terminal. The terminal receives the DCI for scheduling the PDSCH or PUSCH and identifies the activated DL / UL BWP pair based on the BPI. In the case of a downlink carrier (or cell) operating in FDD, the base station includes a BPI indicating the activated BWP in the DCI for scheduling the PDSCH to change the DL BWP of the terminal. In the case of an uplink carrier (or cell) operating in FDD, the base station includes a BPI indicating the activated BWP in the DCI for scheduling the PDSCH to change the UL BWP of the terminal.

[0088] Figure 8 is a conceptual diagram explaining carrier aggregation. Carrier aggregation refers to a method in which a terminal uses a plurality of frequency blocks or (logical) cells consisting of uplink resources (or component carriers) and / or downlink resources (or component carriers) in one large logical frequency band so that a wireless communication system can use a wider frequency band. Hereinafter, for convenience of explanation, the term "component carrier" will be used.

[0089] Referring to FIG. 8, as an example of a 3GPP NR system, the entire system band includes up to 16 component carriers, and each component carrier has a bandwidth of up to 400 MHz. The component carrier includes one or more physically contiguous subcarriers. Although each component carrier is shown to have the same bandwidth in FIG. 8, this is merely an example, and each component carrier may have a different bandwidth. Also, although each component carrier is shown to be adjacent to each other on the frequency axis, the drawing is a logical concept, and each component carrier may be physically adjacent to each other or separated from each other.

[0090] A different center frequency is used in each component carrier. Also, a common center frequency is used in physically adjacent component carriers. In the embodiment of FIG. 8, if it is assumed that all component carriers are physically adjacent, center frequency A is used in all component carriers. Also, if it is assumed that each component carrier is not physically adjacent, center frequency A and center frequency B are used in each component carrier.

[0091] When the entire system band is expanded by carrier aggregation, the frequency band used for communication with each terminal is defined in component carrier units. Terminal A uses the entire system band of 100 MHz and communicates using all five component carriers. Terminal B1 ~B 5 Terminal C uses only 20MHz bandwidth and communicates using one component carrier. 1 and C 2 Each terminal uses only a 40 MHz bandwidth and communicates using two component carriers. The two component carriers may or may not be logically / physically adjacent. In the embodiment of FIG. 8, terminal C 1 uses two non-adjacent component carriers, and terminal C 2 This shows the case where two adjacent component carriers are used.

[0092] 9 is a diagram for explaining single carrier communication and multi-carrier communication, in particular, FIG 9(a) shows a subframe structure of a single carrier, and FIG 9(b) shows a subframe structure of a multi-carrier.

[0093] Referring to FIG. 9(a), a general wireless communication system transmits or receives data through one DL band and one corresponding UL band in the FDD mode. In another specific embodiment, in the TDD mode, the wireless communication system divides a wireless frame into an uplink time unit and a downlink time unit in the time domain, and transmits or receives data through the uplink / downlink time unit. Referring to FIG. 9(b), three 20 MHz component carriers (CCs) are aggregated in the UL and DL, respectively, to support a bandwidth of 60 MHz. The CCs are adjacent or non-adjacent to each other in the frequency domain. Although FIG. 9(b) illustrates a case in which the bandwidth of the UL CC and the bandwidth of the DL CC are the same and symmetrical for convenience, the bandwidth of each CC may be determined independently. Also, asymmetric carrier aggregation in which the number of UL CCs and the number of DL CCs are different is possible. The DL / UL CC allocated / configured to a specific terminal through RRC is called a serving DL / UL CC of the specific terminal.

[0094] The base station activates some or all of the serving CCs of the terminal, or deactivates some of the CCs, to communicate with the terminal. The base station may change the CCs to be activated / deactivated, or may change the number of CCs to be activated / deactivated. When the base station allocates CCs available to the terminal in a cell-specific or terminal-specific manner, at least one of the CCs once allocated may not be deactivated unless the CC allocation for the terminal is completely reconfigured or the terminal performs a handover. A CC that is not deactivated by the terminal is called a primary CC (PCC) or PCell (primary cell), and a CC that the base station can activate / deactivate freely is called a secondary CC (SCC) or SCell (secondary cell).

[0095] Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of downlink and uplink resources, i.e., a combination of DL CC and UL CC. A cell consists of DL resources alone or a combination of DL and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of DL resources (or DL ​​CC) and the carrier frequency of UL resources (or UL CC) is indicated by system information. Carrier frequency means the center frequency of each cell or CC. A cell corresponding to a PCC is called a PCell, and a cell corresponding to a SCC is called a SCell. A carrier corresponding to a PCell in the downlink is a DL PCC, and a carrier corresponding to a PCell in the uplink is a UL PCC. Similarly, a carrier corresponding to a SCell in the downlink is a DL SCC, and a carrier corresponding to a SCell in the uplink is a UL SCC. Depending on the terminal capacity, a serving cell(s) consists of one PCell and zero or more SCells. For a UE in RRC_CONNECTED state but with no carrier aggregation configured or that does not support carrier aggregation, there is only one serving cell consisting of only a PCell.

[0096] As described above, the term cell used in carrier aggregation is different from the term cell referring to a certain geographical area in which communication services are provided by one base station or one antenna group. In order to distinguish between a cell referring to a certain geographical area and a cell of carrier aggregation, in the present invention, a cell of carrier aggregation is referred to as CC, and a cell of a geographical area is referred to as cell.

[0097] FIG. 10 is a diagram showing an example in which a cross-carrier scheduling technique is applied. If cross-carrier scheduling is configured, a control channel transmitted through a first CC schedules a data channel transmitted through a first CC or a second CC using a carrier indicator field (CIF). The CIF is included in the DCI. In other words, a scheduling cell is configured, and a DL grant / UL grant transmitted from the PDCCH region of the scheduling cell schedules the PDSCH / PUSCH of the scheduled cell. That is, there is a PDCCH region of the scheduled cell that has a scraping region for multiple component carriers. A PCell is basically a scheduling cell, and a specific SCell is designated as a scheduling cell by a higher layer.

[0098] In the embodiment of FIG. 10, it is assumed that three DL CCs are merged. Here, it is assumed that DL component carrier #0 is DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are DL SCC (or SCell). It is also assumed that DL PCC is configured as PDCCH monitoring CC. If cross-carrier scheduling is not configured by terminal-specific (or terminal-group-specific, or cell-specific) higher layer signaling, CIF is disabled, and each DL CC transmits only PDCCH that schedules its own PDSCH without CIF according to NR PDCCH rules (non-cross-carrier scheduling, self-carrier scheduling). On the other hand, if cross-carrier scheduling is configured by UE-specific (or UE-group-specific, or cell-specific) higher layer signaling, the CIF is enabled, and a specific CC (e.g., DL PCC) transmits not only a PDCCH for scheduling the PDSCH of DL CC A but also a PDCCH for scheduling the PDSCH of other CCs using the CIF (cross-carrier scheduling). On the other hand, the PDCCH is not transmitted in other DL CCs. Therefore, depending on whether cross-carrier scheduling is configured in the terminal, the terminal monitors a PDCCH that does not include a CIF to receive a self-carrier scheduled PDSCH, or monitors a PDCCH that includes a CIF to receive a cross-carrier scheduled PDSCH.

[0099] 9 and 10 illustrate the subframe structure of the 3GPP LTE-A system, the same or similar structure can be applied to the 3GPP NR system, however, in the 3GPP NR system, the subframes in FIG. 9 and 10 are switched to slots.

[0100] 11 is a diagram showing a code block group (CBG) configuration and its time-frequency resource mapping according to an embodiment of the present invention. More specifically, FIG. 11(a) shows an embodiment of a CBG configuration included in one transport block (TB), and FIG. 11(b) shows time-frequency resource mapping of the corresponding CBG configuration.

[0101] The maximum supportable length of a channel code is defined. For example, the maximum supportable length of turbo codes used in 3GPP LTE(-A) is 6144 bits. However, the length of a transport block (TB) transmitted on a PDSCH may be longer than 6144 bits. If the length of a TB is longer than the maximum supportable length, the TB is divided into code blocks (CBs) of up to 6144 bits in length. Each CB is a unit for channel coding. Additionally, for efficient retransmission, several CBs may be bundled to form one CBG. A terminal and a base station require information on how a CBG is configured.

[0102] Within the TB, the CBG and CB are configured according to various embodiments. According to one embodiment, the number of available CBGs is determined to a fixed value or configured in RRB configuration information between the base station and the terminal. In this case, the number of CBs is determined according to the length of the TB, and the CBG is configured according to the determined number information. According to another embodiment, the number of CBs included in one CBG may be determined to a fixed value or configured in RRB configuration information between the base station and the terminal. In this case, if the number of CBs is determined according to the length of the TB, the number of CBGs is set according to the number information of CBs per one CBG.

[0103] Referring to the embodiment of FIG. 11(a), one TB is divided into eight CBs. The eight CBs are further aggregated into four CBGs. Such a mapping relationship between the CBs and the CBGs (or the CBG configuration) is statically set between the base station and the terminal, or semi-statically set by RRC configuration information. According to another embodiment, the mapping relationship is set through dynamic signaling. When the terminal receives the PDCCH transmitted by the base station, the terminal directly or indirectly identifies the mapping relationship between the CBs and the CBGs (or the CBG configuration) through destination information and / or implicit information. One CBG may include only one CB or may include all CBs constituting one TB. Incidentally, the technique proposed in the embodiment of the present invention is applicable regardless of the CB and the CBG configuration.

[0104] Referring to FIG. 11(b), the CBGs constituting one TB are mapped to the time-frequency resources in which the PDSCH is scheduled. According to an embodiment, each CBG is first allocated to the frequency axis and then extended to the time axis. If a PDSCH consisting of one TB including four CBGs is allocated to seven ODFM symbols, CBG0 is transmitted over the first and second OFDM symbols, CBG1 is transmitted over the second, third, and fourth OFDM symbols, CBG2 is transmitted over the fourth, fifth, and sixth OFDM symbols, and CBG3 is transmitted over the sixth and seventh OFDM symbols. Such a time-frequency mapping relationship allocated between the CBGs and the PDSCH is determined between the terminals. However, the mapping relationship shown in FIG. 11(b) is an embodiment for explaining the present invention, and the technique proposed in the embodiment of the present invention may be applied regardless of the time-frequency mapping relationship of the CBGs.

[0105] FIG. 12 is a diagram showing a process in which a base station performs TB-based transmission or CBG-based transmission, and a terminal transmits a HARQ-ACK in response thereto. Referring to FIG. 12, a base station configures a transmission method suitable for a terminal, among TB-based transmission and CBG-based transmission. The terminal transmits HARQ-ACK bit(s) according to the transmission method configured by the base station to a PUCCH or PUSCH. The base station configures a PDCCH to schedule a PDSCH to be transmitted to the terminal. The PDCCH schedules a TB-based transmission and / or a CBG-based transmission. For example, one TB or two TBs are scheduled in the PDCCH. If one TB is scheduled, the terminal should feed back a 1-bit HARQ-ACK. If two TBs are scheduled, the terminal should feed back a 2-bit HARQ-ACK for each of the two TBs. In order to eliminate ambiguity between the base station and the terminal, there is a predetermined order between each bit of the 2-bit HARQ-ACK and the two TBs. Incidentally, if the MIMO transmission rank or layer is low, one TB is transmitted over one PDSCH, and if the MIMO transmission rank or layer is high, two TBs are transmitted over one PDSCH.

[0106] The terminal transmits a 1-bit TB-based HARQ-ACK for each TB to inform the base station of whether each TB was successfully received. To generate a HARQ-ACK for one TB, the terminal checks whether there is a reception error for the corresponding TB via the TB-CRC. If the TB-CRC check for the TB is successful, the terminal generates an ACK for the HARQ-ACK for the corresponding TB. However, if a TB-CRC error occurs for the TB, the terminal generates a NACK for the HARQ-ACK for the corresponding TB. The terminal transmits the TB-based HARQ-ACK(s) thus generated to the base station. The base station retransmits the TB for which a NACK was responded to among the TB-based HARQ-ACK(s) received from the terminal.

[0107] In addition, the terminal transmits a 1-bit CBG-based HARQ-ACK for each CBG to inform the base station of the success or failure of reception of each CBG. To generate a HARQ-ACK for one CBG, the terminal decodes all CBs included in the CBG and checks whether there is a reception error for the corresponding CB through the CB-CRC. If the terminal successfully receives all CBs constituting one CBG (i.e., if all CB-CRCs are successfully checked), the terminal generates an ACK for the HARQ-ACK of the corresponding CBG. However, if the terminal does not successfully receive at least one of the CBs constituting one CBG (i.e., if at least one CB-CRC error occurs), the terminal generates a NACK for the HARQ-ACK of the corresponding CBG. The terminal transmits the CBG-based HARQ-ACK(s) generated in this way to the base station. The base station retransmits the CBG for which a NACK was responded to among the CBG-based HARQ-ACK(s) received from the terminal. According to one embodiment, the CB configuration of the retransmitted CBG is the same as the CB configuration of the previously transmitted CBG. The length of the CBG-based HARQ-ACK bit(s) transmitted by the terminal to the base station is determined based on the number of CBGs transmitted over the PDSCH or the maximum number of CBGs consisting of an RRC signal. Also, as in the above embodiment, a TB-based HARQ-ACK may be additionally transmitted in addition to the CBG-based HARQ-ACK. In this case, the TB-based HARQ-ACK indicates whether the TB-CRC check is successful or not.

[0108] According to an embodiment of the present invention, CBG-based HARQ-ACK feedback is used for successful transmission of TB. The base station instructs the terminal to transmit CBG-based HARQ-ACK. At this time, a retransmission method based on CBG-based HARQ-ACK is used. The CBG-based HARQ-ACK is transmitted via PUCCH. Also, if UCI is set to be transmitted via PUSCH, the CBG-based HARQ-ACK may be transmitted via the corresponding PUSCH. In PUCCH, the setting of HARQ-ACK resource is configured via RRC signal. Also, the HARQ-ACK resource to be actually transmitted is indicated via PDCCH that schedules PDSCH transmitted based on CBG. The terminal transmits HARQ-ACK(s) regarding successful reception of the transmitted CBG via one or more PUCCH resources indicated via PDCCH among PUCCH resources configured by RRC.

[0109] The base station identifies whether the terminal has successfully received the CBG(s) transmitted to the terminal through the CBG-based HARQ-ACK feedback of the terminal. That is, through the HARQ-ACK for each CBG received from the terminal, the base station recognizes the CBG(s) that the terminal has successfully received and the CBG(s) that the terminal has failed to receive. The base station performs CBG retransmission based on the received CBG-based HARQ-ACK. More specifically, the base station bundles and retransmits only the CBG(s) that have failed to be received in one TB and are responded to with HARQ-ACK. At this time, the CBG(s) that have failed to be received are excluded from the retransmission. The base station schedules the CBG(s) to be retransmitted to one PDSCH and transmits it to the terminal.

[0110] The number of CBG(s) transmitted through the PDSCH may vary during the CBG retransmission process for transmitting one TB. Therefore, the terminal needs to transmit the reception success or failure for the CBG(s) transmitted from the corresponding PDSCH through the HARQ-ACK. However, the terminal does not need to transmit the HARQ-ACK(s) for the CBG(s) for which the ACK has already been transmitted to the base station and has not been retransmitted from the corresponding PDSCH. As described above, the HARQ-ACK bit(s) is reduced according to the number of CBGs transmitted from the PDSCH. This not only increases the reliability of the HARQ-ACK, but also allows unused HARQ-ACK resources to be reused as HARQ-ACK resources for the CBG(s) corresponding to the same terminal or other TBs of the same terminal, thereby reducing the overhead of the uplink control channel. However, despite the above-mentioned advantages, the method of transmitting the HARQ-ACK bit(s) according to the number of CBGs transmitted from the PDSCH may cause disadvantages in the following two situations.

[0111] i) After the terminal transmits a PUCCH (or a PUSCH including an HARQ-ACK) carrying an HARQ-ACK, a NACK-to-ACK error occurs from the base station. In this case, the base station determines that the transmission of the CBG(s) to be retransmitted is successful, and does not transmit it via the next PDSCH for retransmission. The terminal expects retransmission of the CBG(s) that it has failed to receive, but since the corresponding CBG(s) is not transmitted via the next PDSCH, it is requested to transmit a NACK(s) to retransmit the corresponding CBG(s). However, since the corresponding CBG(s) is not transmitted via the next PDSCH for retransmission, the terminal cannot retransmit the HARQ-ACK for the corresponding CBG(s). Therefore, a method for improving a NACK-to-ACK error that may occur from the transmission of a PUCCH (or a PUSCH including an HARQ-ACK) carrying an HARQ-ACK from the terminal is required.

[0112] ii) In CBG-based transmission, the terminal judges whether the CBG is successfully received depending on whether the CRC of the CB included in the CBG is successful. That is, if the CB-CRC check of all CBs included in the CBG is successful, the terminal transmits an ACK as a HARQ-ACK for the corresponding CBG. On the other hand, if an error occurs in even one of the CBs included in the CBG, the terminal transmits a NACK as a HARQ-ACK for the corresponding CBG. However, whether the TB is successfully received depends on whether the TB-CRC attached to the TB is successfully checked. Therefore, the terminal may determine that it has successfully received all CBG(s) and transmit an ACK as a HARQ-ACK corresponding to the corresponding CBG(s), but the TB-CRC check may fail, resulting in a situation where the TB is not successfully received. Therefore, a method for improving this situation is required.

[0113] According to an embodiment of the present invention, a fallback indicator is used as a method for solving the above problems that may occur when using a method of transmitting HARQ-ACK bit(s) according to the number of CBGs transmitted from a PDSCH. The fallback indicator is an indicator for retransmitting all CBGs of one TB via a PDSCH (hereinafter, referred to as a fallback mode). A terminal generates a fallback indicator according to the following embodiment and transmits the fallback indicator together with a HARQ-ACK via a PUCCH resource that has already been allocated. The fallback indicator indicates one of two states. In the embodiment of the present invention, the first state is called a "fallback mode request" and the second state is called a "non-fallback request". The "feedback mode request" is a state in which retransmission of all CBGs of one TB is requested, and the "non-fallback request" is a state in which the retransmission of all CBGs is not requested. According to an additional embodiment of the present invention, the fallback indicator is also used for a TB-based HARQ-ACK. A specific embodiment of TB-based HARQ-ACK will be described later.

[0114] According to an embodiment of the present invention, only one CBG is configured for one TB in a terminal configured to operate based on a CBG. That is, all CBs included in one TB are configured in one CBG. In this case, the HARQ-ACK feedback transmitted by the terminal is determined according to whether the TB-CRC is successful. That is, if the TB-CRC check is successful, the terminal transmits an ACK as a HARQ-ACK for the corresponding CBG, and if the TB-CRC check is unsuccessful, the terminal transmits a NACK as a HARQ-ACK for the corresponding CBG. In this case, whether or not to perform the fallback mode is determined from the ACK / NACK for the CBG without explicitly transmitting a fallback indicator. More specifically, a terminal expecting to operate in the fallback mode transmits a NACK as a HARQ-ACK for the CBG. If a NACK is transmitted as a HARQ-ACK from the terminal, the base station determines that the fallback mode is necessary, and accordingly retransmits all CBGs of the corresponding TB via a PDSCH.

[0115] According to another embodiment of the present invention, in a terminal configured to operate based on a CBG, N CBGs are configured for one TB (where N is a natural number greater than 1). That is, one TB consists of two or more CBGs. In this case, a method in which the terminal transmits a fallback indicator and a HARQ-ACK is as follows.

[0116] First, N CBGs (i.e., all CBGs) for one TB are transmitted on the PDSCH. In this case, the terminal determines whether each CBG is successfully received through the CB-CRC, and transmits HARQ-ACK for the N CBGs through the previously configured or indicated PUCCH resource. If the terminal checks all CB-CRCs included in each CBG successfully, it transmits an ACK as a HARQ-ACK for the corresponding CBG. Otherwise, the terminal transmits a NACK as a HARQ-ACK for the corresponding CBG. The HARQ-ACK for the CBG is transmitted through a PUCCH or a HARQ-ACK in a PUSCH transmitted by the terminal. The base station bundles the CBGs for which the terminal has responded with a NACK and retransmits them through the PDSCH. In this case, whether or not to perform the fallback mode is determined from the ACK / NACK for the CBG without an explicit transmission of a fallback indicator. More specifically, a terminal that desires to operate in the fallback mode transmits a NACK as a HARQ-ACK for the CBG. If the UE transmits a NACK as a HARQ-ACK for all CBGs, the base station determines that a fallback mode is necessary and retransmits all CBGs of the corresponding TB via the PDSCH.

[0117] Table 4 shows the HARQ-ACK feedback transmitted by the terminal when N=2 and the corresponding operation. If the terminal's HARQ-ACK is [ACK ACK], the base station determines that the terminal has successfully received the corresponding TB. If the terminal's HARQ-ACK is [ACK NACK], the base station determines that the terminal has successfully received the first CBG but has failed to receive the second CBG. Therefore, the base station retransmits the second CBG via the PDSCH. If the terminal's HARQ-ACK is [NACK ACK], the base station determines that the terminal has successfully received the second CBG but has failed to receive the first CBG. Therefore, the base station retransmits the first CBG via the PDSCH. If the terminal's HARQ-ACK is [NACK NACK], the base station determines that the terminal requires a feedback mode. Therefore, the base station bundles the first CBG and the second CBG and retransmits them via the PDSCH.

[0118] [Table 4]

[0119] Next, for a natural number M less than N, M CBGs (i.e., some CBGs) for one TB are transmitted on the PDSCH. If some CBGs for one TB are transmitted, the method in which the UE transmits a fallback indicator and HARQ-ACK is as in the following embodiments. In each embodiment, duplicated descriptions are omitted for parts that are the same as or correspond to the previous embodiments.

[0120] According to a first embodiment of the present invention, the terminal transmits M+1 bits obtained by bundling an ACK / NACK bit and a 1-bit fallback indicator for each of M CBGs via a HARQ-ACK resource. In this case, the 1-bit fallback indicator is given a higher priority than the M-bit HARQ-ACK, and whether or not to perform the fallback mode is determined. The terminal determines whether or not each transmitted CBG is successfully received via a CB-CRC. More specifically, since a maximum of N CBGs may be transmitted to the terminal, the terminal is assigned a PUCCH resource capable of accommodating N HARQ-ACK bits. The terminal transmits 1 to N HARQ-ACK bits via the corresponding resource. The terminal transmits (M+1)-bit feedback by bundling a 1-bit fallback indicator with the M-bit HARQ-ACK in the HARQ-ACK resource. The base station receives (M+1)-bit feedback via the PUCCH resource of the PUCCH or PUSCH transmitted from the terminal, thereby obtaining an M-bit HARQ-ACK and fallback indicator for the transmitted CBG.

[0121] FIG. 13 is a diagram illustrating an embodiment of a method for interpreting a received HARQ-ACK feedback and a fallback indicator. Referring to FIG. 13, the base station gives priority to a 1-bit fallback indicator over an M-bit HARQ-ACK and determines whether a fallback mode is required. If a fallback mode is required, the terminal transmits a fallback indicator indicating a "fallback mode request", otherwise, the terminal transmits a fallback indicator indicating a "non-fallback request". The base station checks what state the received fallback indicator indicates. If the fallback indicator indicates a "fallback mode request", the base station performs the fallback mode while ignoring information such as ACK / NACK / DTX of the M-bit HARQ-ACK. That is, the base station bundles all CBGs of the corresponding TB and retransmits them via the PDSCH. If the fallback indicator indicates a "non-fallback request", the base station retransmits the CBG according to the information of the M-bit HARQ-ACK. That is, the base station bundles the CBG(s) for which NACK has been responded and retransmits them via the PDSCH.

[0122] According to a second embodiment of the present invention, the terminal uses the remaining (NM) bits, excluding M HARQ-ACK bits, from the N bits reserved through the HARQ-ACK resource, as a fallback indicator. In this case, the (NM)-bit fallback indicator is given priority over the M-bit HARQ-ACK, and it is determined whether to perform the fallback mode. The terminal transmits N bits, which are aggregating ACK / NACK bits and (NM)-bit fallback indicators for each of M CBGs, through the HARQ-ACK resource. That is, the terminal transmits N-bit feedback by aggregating the (NM)-bit fallback indicator with the M-bit HARQ-ACK in the HARQ-ACK resource. The base station receives the N-bit feedback through the PUCCH or PUSCH transmitted from the terminal, and obtains the M-bit HARQ-ACK and (MN)-bit fallback indicator for the transmitted CBG. The (MN)-bit fallback indicator indicates one of a "fallback mode requested" and a "not-fallback requested" state. Since the (MN)-bit fallback indicator is made up of multiple bits, it can increase the reliability of transmission compared to a 1-bit fallback indicator.

[0123] With reference to FIG. 13, a method of interpreting the received HARQ-ACK feedback and fallback indicator will be described below. The base station gives priority to the (NM)-bit fallback indicator over the M-bit HARQ-ACK and determines whether the fallback mode is necessary. If the fallback mode is necessary, the terminal transmits the (NM)-bit fallback indicator to indicate a "fallback mode request", otherwise, the terminal transmits the (NM)-bit fallback indicator to indicate a "non-fallback request". The base station checks what state the received fallback indicator indicates. If the fallback indicator indicates a "fallback mode request", the base station performs the fallback mode. If the fallback indicator indicates a "non-fallback request", the base station retransmits the CBG according to the information of the M-bit HARQ-ACK. A specific embodiment thereof is as described in the first embodiment.

[0124] Table 5 shows the fallback indicator and HARQ-ACK feedback transmitted by the UE when N = 3 and M = 2, and the corresponding operation. In this case, one TB consists of three CBGs, and the first CBG and the second CBG, which are part of the CBGs for one TB, are transmitted on the PDSCH.

[0125] [Table 5]

[0126] Referring to FIG. 5, the base station checks the fallback indicator preferentially over the HARQ-ACK bit. If the fallback indicator indicates a "fallback mode request", the base station always performs the fallback mode. That is, the base station retransmits all CBGs constituting the corresponding TB, that is, the first CBG, the second CBG, and the third CBG, on the PDSCH. If the fallback indicator indicates a "non-fallback request", the base station retransmits the CBGs according to the information of the 2-bit HARQ-ACK. That is, if the HARQ-ACK of the terminal is [ACK ACK], the base station determines that the terminal has successfully received two CBGs. If the HARQ-ACK of the terminal is [ACK NACK], the base station determines that the terminal has successfully received the first CBG but has failed to receive the second CBG. Therefore, the base station retransmits the second CBG via the PDSCH. If the terminal's HARQ-ACK is [NACK ACK], the base station determines that the terminal has successfully received the second CBG but has failed to receive the first CBG. Therefore, the base station retransmits the first CBG via the PDSCH. If the terminal's HARQ-ACK is [NACK NACK], the base station determines that the terminal has failed to receive the first and second CBGs. Therefore, the base station bundles the first and second CBGs and retransmits them via the PDSCH.

[0127] According to the third embodiment of the present invention, the terminal transmits M+1 bits, which are obtained by bundling ACK / NACK bits and a 1-bit fallback indicator for each of M CBGs, via a PUCCH resource. At this time, the M-bit HARQ-ACK is given a priority (or an equal priority) over the 1-bit fallback indicator, and it is determined whether to perform the fallback mode. The embodiment in which the terminal transmits the 1-bit fallback indicator together with the M-bit HARQ-ACK via the HARQ-ACK resource and the base station receives it is the same as described in the first embodiment.

[0128] FIG. 14 is a diagram showing another embodiment of a method for interpreting a received HARQ-ACK feedback and a fallback indicator. Referring to FIG. 14, the base station gives priority (or equal priority) to the M-bit HARQ-ACK over the 1-bit fallback indicator and determines whether the fallback mode is necessary. That is, if all the M-bit HARQ-ACKs are NACK, the base station checks the 1-bit fallback indicator to determine whether the fallback mode is necessary. If the fallback mode is necessary, the terminal transmits all the M-bit HARQ-ACKs indicating NACK and the fallback indicator indicating "fallback mode request". In this case, the base station bundles all the CBGs of the corresponding TB and retransmits them via the PDSCH. Otherwise, the base station determines that the fallback mode is not necessary. That is, if there is at least one ACK among the M-bit HARQ-ACKs, the base station does not perform the fallback mode regardless of the value indicated by the feedback indicator. At this time, the base station bundles the CBG(s) for which NACK has been responded according to the information of the M-bit HARQ-ACK, and retransmits them via the PDSCH.

[0129] According to the fourth embodiment of the present invention, the terminal uses the remaining (NM) bit(s) obtained by removing M HARQ-ACK bit(s) from the N bits reserved through the HARQ-ACK resource as a fallback indicator. In this case, the M-bit HARQ-ACK is given a priority (or an equal priority) over the (NM)-bit fallback indicator, and it is determined whether to perform the fallback mode. The embodiment in which the terminal transmits the (NM)-bit fallback indicator together with the M-bit HARQ-ACK through the HARQ-ACK resource and the base station receives it is the same as described in the second embodiment.

[0130] With reference to FIG. 14, the method of interpreting the received HARQ-ACK feedback and fallback indicator will be described as follows. The base station gives priority (or equal priority) to the M-bit HARQ-ACK over the (NM)-bit fallback indicator and determines whether the fallback mode is necessary. That is, if all the M-bit HARQ-ACKs are NACK, the base station checks the (NM)-bit fallback indicator to determine whether the fallback mode is necessary. If the fallback mode is necessary, the terminal transmits all the M-bit HARQ-ACKs indicating NACK and the (NM)-bit fallback indicator indicating "fallback mode request". In this case, the base station bundles all the CBGs of the corresponding TB and retransmits them via the PDSCH. Otherwise, the base station determines that the fallback mode is not necessary. That is, if there is at least one ACK among the M-bit HARQ-ACKs, the base station does not perform the fallback mode regardless of the value indicated by the feedback indicator. At this time, the base station bundles the CBG(s) for which NACK has been responded according to the information of the M-bit HARQ-ACK, and retransmits them via the PDSCH.

[0131] Table 6 shows the fallback indicator and HARQ-ACK feedback transmitted by the UE when N = 3 and M = 2, and the corresponding operation. In this case, one TB consists of three CBGs, and the first CBG and the second CBG, which are part of the CBGs for one TB, are transmitted on the PDSCH.

[0132] [Table 6]

[0133] Referring to Table 6, if the 2-bit HARQ-ACK is [NACK NACK] and the fallback indicator indicates a "fallback mode request", the base station performs the fallback mode. That is, the base station retransmits all CBGs constituting the corresponding TB, that is, the first CBG, the second CBG, and the third CBG, on the PDSCH. Otherwise, the base station determines that the fallback mode is not necessary. In this case, the base station retransmits the CBG according to the 2-bit HARQ-ACK information. That is, if the HARQ-ACK of the terminal is [ACK ACK], the base station determines that the terminal has successfully received two CBGs, regardless of the value of the fallback indicator. If the HARQ-ACK of the terminal is [ACK NACK], the base station determines that the terminal has successfully received the first CBG but has failed to receive the second CBG, regardless of the value of the fallback indicator. Therefore, the base station retransmits the second CBG via the PDSCH. If the UE's HARQ-ACK is [NACK ACK], regardless of the value of the fallback indicator, the base station determines that the UE has successfully received the second CBG but has failed to receive the first CBG. Therefore, the base station retransmits the first CBG via the PDSCH. If the UE's HARQ-ACK is [NACK NACK] and the fallback indicator indicates "non-fallback request", the base station determines that the UE has failed to receive the first and second CBGs. Therefore, the base station bundles the first and second CBGs and retransmits them via the PDSCH.

[0134] According to a fifth embodiment of the present invention, the retransmission of the TB is performed through retransmission of the upper layer without an explicit fallback indicator. That is, no feedback mode is used to recover the erroneous transmission of the physical layer. According to one embodiment, the base station and the terminal do not have an explicit fallback indicator resource, and only HARQ-ACK resources for the CBG exist. In this case, if the CBG(s) that the terminal needs to retransmit are not included in the PDSCH transmission, the terminal transmits an ACK as a HARQ-ACK for all CBGs of the corresponding PDSCH, regardless of the success of the CB-CRC and the success of the TB-CRC of the corresponding PDSCH transmission. In this way, the terminal recognizes the failure of reception of the corresponding TB, but prevents further unnecessary retransmission by transmitting an ACK for all CBGs. The unsuccessfully received TB is recovered through retransmission in the upper layer, not through retransmission via HARQ-ACK transmission in the physical layer.

[0135] FIG. 15 is a diagram illustrating an example in which the terminal transmits HARQ-ACK and fallback indicator for CBG(s) according to the above-mentioned embodiment. According to the embodiment of FIG. 15, the base station configures three CBGs for one TB (i.e., N=3), and the terminal is assigned PUCCH resources for transmitting a 3-bit HARQ-ACK. In the first PDSCH transmission, the base station transmits CBG#1, CBG#2, and CBG#3. The terminal successfully receives CBG#3 among the three CBGs, but fails to receive CBG#1 and CBG#2. Therefore, the terminal transmits [NACK NACK ACK] as a 3-bit HARQ-ACK for the first PDSCH transmission. In the second PDSCH transmission, the base station retransmits only CBG#1 and CBG#2, excluding CBG#3 to which the terminal has already responded with an ACK. The terminal transmits a 3-bit HARQ-ACK in response to the second PDSCH transmission. In this case, the terminal uses the first two bits of the 3-bit HARQ-ACK to indicate whether or not it has received retransmitted CBG#1 and CBG#2, and uses the last bit corresponding to CBG#3 as a fallback indicator.

[0136] 16 to 19 are diagrams illustrating an additional embodiment in which a terminal transmits HARQ-ACK feedback and a fallback indicator for CBG(s). According to the additional embodiment of the present invention, the length of the HARQ-ACK payload transmitted by the terminal is configured based on the maximum number of CBGs consisting of RRC signals. Thus, N CBG-based HARQ-ACK bits are configured in the terminal. Hereinafter, in the embodiment of FIG. 16 to FIG. 19, the maximum number of CBGs consisting of RRC signals is N, and the number of CBG(s) included in the TB transmitted by the base station is M. In this case, M bits of the N-bit HARQ-ACK are CBG-based HARQ-ACKs (i.e., M-bit CBG-based HARQ-ACKs) indicating whether each CBG has been successfully received. Also, if M is smaller than N, the remaining NM bits of the N-bit HARQ-ACK are fallback indicators.

[0137] In an embodiment of the present invention, the HARQ-ACK indicating whether the terminal has successfully received each CBG transmitted via the PDSCH is referred to as a CBG-based HARQ-ACK or a CBG-level HARQ-ACK. Also, as described above, in an embodiment of the present invention, the fallback indicator is also referred to as a TB-based HARQ-ACK. In an embodiment of the present invention, the HARQ-ACK indicating whether the terminal has successfully received each TB transmitted via the PDSCH is referred to as a TB-based HARQ-ACK or a TB-level HARQ-ACK.

[0138] According to embodiments of the present invention, the (NM)-bit fallback indicator may be configured in various ways. According to one embodiment, the (NM)-bit fallback indicator may be configured as all ACKs or all NACKs. According to another embodiment, the (NM)-bit fallback indicator may be configured as NM bit(s) of a 1-bit TB-based HARQ-ACK repeated. According to yet another embodiment, the (NM)-bit fallback indicator may be configured based on the value of an M-bit CBG-based HARQ-ACK. If M is a submultiple of N, the (NM)-bit fallback indicator may be configured as M-bit CBG-based HARQ-ACK repeated.

[0139] Table 7 shows an embodiment of constructing 4-bit HARQ-ACK feedback when N=4 and M=1 to 4. First, if M=1, HARQ-ACK b0 for CBG#0 is repeated four times to construct 4-bit HARQ-ACK[b0 b0 b0 b0]. Next, if M=2, HARQ-ACK b0 for CBG#0 and HARQ-ACK b1 for CBG#1 are repeated twice to construct 4-bit HARQ-ACK[b0 b1 b0 b1]. Next, if M=3, 4-bit HARQ-ACK is constructed as [b0 b1 b2 bx] using HARQ-ACK b0 for CBG#0, HARQ-ACK b1 for CBG#1, HARQ-ACK b2 for CBG#2, and X determined by the combination of b0, b1, and b2. According to an embodiment, x is obtained through an XOR operation of b0, b1, and b2. According to another embodiment, x is determined to be a value of b0+b1+b2 (mod 2). Table 7 shows an embodiment for configuring N-bit HARQ-ACK feedback, and N-bit HARQ-ACK feedback is configured by combining at least one of the above listed embodiments.

[0140] [Table 7]

[0141] According to another embodiment of the present invention, the UE is configured with a transmission mode in which two TBs are transmitted in one PDSCH. In this case, the UE transmits 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 UE receives a PDSCH that schedules only one TB, the UE repeats the CBG-based HARQ-ACK for one TB to generate a HARQ-ACK with the length of the CBG-based HARQ-ACK payload for two TBs.

[0142] For example, the terminal may be configured in a transmission mode in which up to two TBs are transmitted, and one TB may consist of up to four CBGs. If only one TB is scheduled to the terminal, the CBG-based HARQ-ACKs [b0 b1 b2 b3] for the four CBGs included in the corresponding TB are repeated twice to form 8-bit HARQ-ACKs [b0 b1 b2 b3 b0 b1 b2 b3]. On the other hand, if only two TBs are scheduled to the terminal, the CBG-based HARQ-ACKs [b0 b1 b2 b3] for the four CBGs included in the first TB and the HARQ-ACKs [c0 c1 c2 c3] for the four CBGs included in the second TB are combined to form 8-bit HARQ-ACKs [b0 b1 b2 b3 c0 c1 c2 c3]. The terminal transmits the HARQ-ACK configured in this way to the base station.

[0143] Meanwhile, even in a transmission mode in which two TBs are transmitted from one PDSCH, the number M of CBGs included in the TB transmitted by the base station is smaller than the maximum number of CBGs consisting of RRC signals, N. In this case, the method of configuring the remaining NM bit(s) excluding M bit(s) from the N-bit HARQ-ACK is the same as the above-mentioned embodiment.

[0144] On the other hand, according to an additional embodiment of the present invention, CBG-based HARQ-ACK(s) for CBG(s) and a fallback indicator (or, TB-based HARQ-ACK) are transmitted via different PUCCH resources from each other. FIGS. 16 to 19 show embodiments in which the terminal transmits CBG-based HARQ-ACK(s) and a fallback indicator via different HARQ-ACK resources from each other.

[0145] First, FIG. 16 shows an example of allocating different HARQ-ACK resources externally for the transmission of CBG-based HARQ-ACK(s) and the transmission of a fallback indicator (or, TB-based HARQ-ACK). Referring to FIG. 16, the base station allocates two HARQ-ACK resources at different times to the terminal. The two HARQ-ACK resources at different times are respectively used for the transmission of CBG-based HARQ-ACK(s) and the transmission of a 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) is configured to be earlier than the resource for transmitting CBG-based HARQ-ACK(s). For example, the terminal is allocated slot n + k1 (i.e., resource A) and slot n + k2 (i.e., resource B) as HARQ-ACK resources for the PDSCH received from slot n (where k1 < k2). Among the said resources, resource A of slot n + k1 is the resource for transmitting the fallback indicator (or, TB-based HARQ-ACK), and resource B of slot n + k2 is the resource for transmitting CBG-based HARQ-ACK(s). On the other hand, the length of the CBG-based HARQ-ACK payload transmitted via resource B is configured based on any one of the number of CBGs transmitted, the maximum number of CBGs consisting of RRC signals, or the number of CBGs that the corresponding TB may have.

[0146] FIG. 17 illustrates an embodiment in which a CBG-based HARQ-ACK(s) and a fallback indicator (or a TB-based HARQ-ACK) are transmitted via different HARQ-ACK resources. According to the embodiment of FIG. 17, the terminal selectively transmits only one of the CBG-based HARQ-ACK(s) and the TB-based HARQ-ACK. More specifically, in a situation in which a terminal in a CBG-based communication transmits a HARQ-ACK to a base station, if the HARQ-ACK(s) for the CBG(s) are both ACK or NACK, the terminal transmits only the TB-based HARQ-ACK and does not transmit the CBG-based HARQ-ACK(s). On the other hand, if the HARQ-ACK(s) for the CBG(s) include at least one ACK and at least one NACK, the terminal transmits only the CBG-based HARQ-ACK(s) and does not transmit the TB-based HARQ-ACK.

[0147] The terminal selects one of two different HARQ-ACK resources according to the type of HARQ-ACK to be transmitted, among the CBG-based HARQ-ACK(s) and the fallback indicator (i.e., the TB-based HARQ-ACK), and transmits the corresponding HARQ-ACK through the selected resource. As shown in FIG. 17(a), when transmitting the TB-based HARQ-ACK, the terminal transmits the TB-based HARQ-ACK through slot n+k1. In this case, the terminal does not transmit the CBG-based HARQ-ACK(s) through slot n+k2. According to an embodiment, if the TB-CRC check is successful, the terminal transmits an ACK as the TB-based HARQ-ACK. On the other hand, if the CB-CRC check is successful but a TB-CRC error occurs, the terminal transmits a NACK as the TB-based HARQ-ACK. In addition, the terminal also transmits a NACK as a TB-based HARQ-ACK when it fails to receive all CBGs (i.e., when all CB-CRCs fail), as shown in FIG. 17(b), when attempting to transmit a CBG-based HARQ-ACK(s), the terminal transmits the CBG-based HARQ-ACK(s) via slot n+k2. In this case, the terminal does not transmit a TB-based HARQ-ACK via slot n+k1.

[0148] In the embodiment of FIG. 17, the operation of the base station is as follows. The base station expects the UE to transmit a TB-based HARQ-ACK through resource A of slot n+k1. If the UE successfully receives the TB-based HARQ-ACK through resource A and the HARQ-ACK is ACK, the base station determines that the UE has successfully received the TB. If the UE successfully receives the TB-based HARQ-ACK through resource A and the HARQ-ACK is NACK, the base station determines that the UE has failed to receive all CBGs (or all CBs). Thus, the base station retransmits all CBGs (or all CBs). If the UE successfully receives the TB-based HARQ-ACK through resource A, the base station determines that the UE does not use resource B (i.e., slot n+k2). Thus, if the UE transmits the TB-based HARQ-ACK through resource A, resource B is used for another purpose. For example, resource B may be used for another user's HARQ-ACK transmission. On the other hand, if the UE does not successfully receive the TB-based HARQ-ACK via resource A, the base station determines that the UE has transmitted a CBG-based HARQ-ACK(s). Therefore, the base station receives the UE's CBG-based HARQ-ACK(s) via resource B in slot n+k2. Based on the CBG-based HARQ-ACK(s), the base station retransmits the CBG(s) that the UE failed to receive.

[0149] Figure 18 shows another embodiment in which the CBG-based HARQ-ACK(s) and the fallback indicator (or TB-based HARQ-ACK) are transmitted via different HARQ-ACK resources. According to the embodiment of Figure 18, the UE transmits only the TB-based HARQ-ACK or transmits both the CBG-based HARQ-ACK(s) and the TB-based HARQ-ACK depending on whether all CBGs have been successfully received.

[0150] As shown in FIG. 18(a), if the terminal successfully receives all CBGs and successfully checks the TB-CRC, the terminal transmits an ACK as a TB-based HARQ-ACK through slot n+k1. In this case, the terminal does not transmit CBG-based HARQ-ACK(s) through slot n+k2. As shown in FIG. 18(b), if the terminal fails to receive at least one CBG or an error occurs in the TB-CRC, the terminal transmits a NACK as a TB-based HARQ-ACK through slot n+k1. In this case, the terminal transmits CBG-based HARQ-ACK(s) through slot n+k2.

[0151] In the embodiment of FIG. 18, the operation of the base station is as follows. The base station always expects the UE to transmit a TB-based HARQ-ACK via resource A of slot n+k1. If the UE's TB-based HARQ-ACK received via resource A is ACK, the base station determines that the UE has successfully received the TB. In this case, the base station determines that the UE does not use resource B (i.e., slot n+k2). Therefore, if the UE's TB-based HARQ-ACK is transmitted via resource A, resource B is used for other purposes. For example, resource B may be used for another user's HARQ-ACK transmission. If the UE has successfully received a TB-based HARQ-ACK via resource A and the HARQ-ACK is NACK (or DTX), the base station determines that the UE has failed to receive at least one CBG. In this case, the base station receives the UE's CBG-based HARQ-ACK(s) via resource B. Based on the CBG-based HARQ-ACK(s), the base station retransmits the CBG(s) that the terminal failed to receive.

[0152] According to another embodiment of the present invention, even if the TB-based HARQ-ACK is ACK, the TB-based HARQ-ACK and the CBG-based HARQ-ACK(s) of the terminal are both transmitted. The base station receives the TB-based HARQ-ACK and the CBG-based HARQ-ACK(s) via the resource A and the resource B, respectively, and determines whether the terminal has successfully received the TB using the received HARQ-ACK. For example, if the TB-based HARQ-ACK is ACK and the CBG-based HARQ-ACK(s) are both ACK, the base station determines that the terminal has successfully received the TB. However, if the TB-based HARQ-ACK is ACK and the CBG-based HARQ-ACK(s) are not ACK, the base station performs CBG-based retransmission based on the CBG-based HARQ-ACK(s). Alternatively, if the TB-based HARQ-ACK is ACK, the base station determines that the terminal has successfully received the TB regardless of the value of the CBG-based HARQ-ACK.

[0153] If the TB-based HARQ-ACK is NACK but the CBG-based HARQ-ACK(s) is not successfully received via resource B, the base station determines that the UE has failed to receive all CBGs and retransmits all CBGs. According to another embodiment, if the TB-based HARQ-ACK is NACK but the CBG-based HARQ-ACK(s) is not successfully received via resource B, the base station determines that an ACK-to-NACK error has occurred in the TB-based HARQ-ACK and determines that the UE has successfully received the corresponding TB.

[0154] Also, if the TB-based HARQ-ACK is NACK and the CBG-based HARQ-ACK(s) are all ACK, the base station assumes that the UE has failed to receive all CBGs and retransmits all CBGs. According to yet another embodiment, if the TB-based HARQ-ACK is NACK and the CBG-based HARQ-ACK(s) are all ACK, the base station assumes that an ACK-to-NACK error has occurred in the TB-based HARQ-ACK and determines that the UE has successfully received the corresponding TB.

[0155] FIG. 19 shows an example in which a terminal receives a PDCCH that schedules a retransmission for a corresponding TB between the transmission of a TB-based HARQ-ACK and the transmission of a CBG-based HARQ-ACK(s). More specifically, when the terminal attempts to transmit a TB-based HARQ-ACK via resource A in slot n + k1 and transmit a CBG-based HARQ-ACK(s) via resource B in slot n + k2, a PDCCH that schedules a retransmission for the corresponding TB is received via slot n + k3 before slot n + k2 (i.e., k3 < k2). In this case, the terminal does not transmit a CBG-based HARQ-ACK(s) via slot n + k2. In this way, if the base station transmits a PDCCH that schedules a retransmission for a TB before slot n + k2 for transmitting a CBG-based HARQ-ACK(s), resource B in slot n + k2 is used for other purposes. For example, resource B may be used for HARQ-ACK transmission of another user.

[0156] According to an embodiment of the present invention, the base station instructs the terminal about information regarding resource A in slot n + k1 and resource B in slot n + k2 in various ways. According to one embodiment, the base station independently instructs offset k1 and offset k2 via DCI. According to another embodiment, the base station notifies or fixes in advance the value of the difference between offset k1 and offset k2 to the terminal, and instructs only one of offset k1 and offset k2 via DCI. The terminal uses the value of the difference between either one of the offsets instructed via DIC and the offset known in advance (or fixed) to obtain the values of offset k1 and offset k2. At this time, the smaller value of the obtained offsets is used as an offset for transmitting a TB-based HARQ-ACK, and the larger value of the offsets is used as an offset for transmitting a CBG-based HARQ-ACK(s).

[0157] If HARQ-ACK multiplexing is configured in the UE, in the above embodiment, the TB-based HARQ-ACK transmitted through resource A of slot n+k1 is a multiplexed TB-based HARQ-ACK for one or more TBs. Also, in the above embodiment, the CBG-based HARQ-ACK(s) transmitted through resource B of slot n+k2 is a multiplexed CBG-based HARQ-ACK for one or more TBs. According to one embodiment, the CBG-based HARQ-ACK(s) transmitted through resource B is generated by multiplexing the CBG-based HARQ-ACK bits for the TBs for which NACK is transmitted as the TB-based HARQ-ACK. That is, for the TBs for which ACK is transmitted as the TB-based HARQ-ACK transmitted through resource A, the CBG-based HARQ-ACK transmission through resource B is not performed.

[0158] Meanwhile, in the above embodiment, the resource is described based on the slot unit, but the present invention is not limited thereto. That is, in a situation such as Short-PUCCH transmission, the slot of the above embodiment is changed to an OFDM symbol. In this case, OFDM symbol n+k1 and / or OFDM symbol n+k2 are the OFDM symbols where PUCCH starts.

[0159] Also, in the above-described embodiments, it is assumed that k1 < k2. However, according to other embodiments of the present invention, the offset k1 and the offset k2 may be set to the same value (i.e., k = k1 = k2). That is, the same time HARQ-ACK resource may be allocated for the transmission of the TB-based HARQ-ACK to the transmission of the CBG-based HARQ-ACK(s). If the terminal is configured in a transmission mode in which two TBs are transmitted from one PDSCH, the terminal selects one of the resources A and B configured in the same slot n + k to perform HARQ-ACK transmission. According to one embodiment, if the HARQ-ACKs for the two TBs transmitted via one PDSCH are both ACKs, the terminal transmits [ACK ACK] as the TB-based HARQ-ACK via the resource A of slot n + k. At this time, the terminal may not use the resource B of slot n + k. If the HARQ-ACKs for the two TBs transmitted via one PDSCH are not both ACKs, the terminal transmits the CBG-based HARQ-ACK for the CBGs included in the two TBs via the resource B of slot n + k. At this time, the terminal may not use the resource A of slot n + k.

[0160] According to an additional embodiment of the present invention, if the CBG-based HARQ-ACKs for a plurality of TBs are multiplexed, a compressed CBG-based HARQ-ACK is used to reduce the payload length. That is, a terminal that uses a compressed CBG-based HARQ-ACK with a reduced payload length from the original CBG-based HARQ-ACK generates the compressed CBG-based HARQ-ACK from the original CBG-based HARQ-ACK according to a determined rule and transmits the compressed CBG-based HARQ-ACK to the base station.

[0161] A first embodiment of generating a compressed CBG-based HARQ-ACK is as follows. The base station selects a state that is expected to occur frequently from among all CBG-based HARQ-ACK states for one TB, and allows the terminal to signal the selected state. Here, the CBG-based HARQ-ACK state refers to a combination of bits that the original CBG-based HARQ-ACK may have. That is, the 4-bit CBG-based HARQ-ACK has a total of 16 states, that is, states [ACK ACK ACK ACK] to [NACK NACK NACK NACK]. The base station selects P states from the original CBG-based HARQ-ACK states. That is, assuming that the number of all TBs transmitted via the PDSCH is I, the CBG-based HARQ-ACK state under the i-th TB is P out of P states. i In this case, the terminal maps the mapped P for all I TBs to the 1st state. i is multiplexed via the following equation to obtain U, and then U is converted to binary to obtain compressed CBG-based HARQ-ACK(s) for all TB(s).

[0162]

number

[0163] The base station receives the compressed CBG-based HARQ-ACK(s) from the terminal, converts the compressed CBG-based HARQ-ACK(s) into a P-ary number, and outputs CBG-based HARQ-ACK status information P i to obtain.

[0164] According to an embodiment, the value of P and information on the P CBG-based HARQ-ACK states selected by the base station are configured through an RRC signal transmitted by the base station to the terminal. According to another embodiment, the value of P is determined based on at least one of the capacity of a PUCCH that the terminal can transmit and the number of TBs (or the number of PDSCHs) that the terminal should transmit. In addition, in order to determine the P CBG-based HARQ-ACK states, all CBG-based HARQ-ACK states are pre-arranged according to a pre-set order. According to an embodiment, the pre-set order is determined based on the occurrence frequency of each state among all CBG-based HARQ-ACK states. For example, a CBG-based HARQ-ACK state indicating a reception error of an adjacent CBG is determined to be in a higher order than a CBG-based HARQ-ACK state indicating a reception error of a non-adjacent CBG. Among all CBG-based HARQ-ACK states, P states are selected based on the pre-arranged order.

[0165] Table 8 shows an example of determining P CBG-based HARQ-ACK states. In the example of Table 8, P states are determined from a total of 16 original CBG-based HARQ-ACK states based on four CBG-based HARQ-ACK bits. Here, the information of the selected P CBG-based HARQ-ACK states is illustrated when P is 2, 4, 6, 9, 11, 14, or 16.

[0166] [Table 8]

[0167] Each of the P selected states is assigned a prearranged order. i As mentioned above, each TB is indexed to the pth state of the original CBG-based HARQ-ACK state. i If the number of original CBG-based HARQ-ACK states is N, N to P mapping is performed. According to an embodiment of the present invention, the original CBG-based HARQ-ACK state is mapped to the pi That is, in the original CBG-based HARQ-ACK state, the NACK bit is mapped to the p i For example, if the second bit in the original CBG-based HARQ-ACK state is NACK (i.e., 0), the state to which the original state can be mapped is one in which the second bit is NACK, i.e., any one of

[0000] ,

[0001] ,

[0010] ,

[0011] ,

[1000] ,

[1001] ,

[1010] , and

[1011] .

[0168] A second embodiment of generating a compressed CBG-based HARQ-ACK is as follows. The maximum number of CBGs consisting of RRC signals is N, and the number of CBGs included in the TB transmitted by the base station is M. In this case, M bits of the N-bit HARQ-ACK are CBG-based HARQ-ACKs indicating whether each CBG was successfully received (i.e., M-bit CBG-based HARQ-ACK). The base station configures the length of the original CBG-based HARQ-ACK payload for one TB based on the maximum number of CBGs consisting of RRC signals. In other words, the original CBG-based HARQ-ACK for one TB consists of N bits. In this case, the original CBG-based HARQ-ACK is [b 0 , b 1 , …, b M-1 , X 0 , X 1 , …, X N-M-1 That is, the original CBG-based HARQ-ACK is represented as M-bit CBG-based HARQ-ACK [b 0 , b 1 , …, b M-1 ] and the remaining NM bits (ra) [X 0 , X 1 , …, X N-M-1 In this case, Xm may be a fixed value (e.g., ACK or NACK) or may be configured based on the value of M-bit CBG-based HARQ-ACK. A specific method for this is as described in the above embodiment.

[0169] In order to reduce the length of the HARQ-ACK payload, the base station instructs the terminal to use a compressed CBG-based HARQ-ACK. The base station signals the instruction information via an RRC signal or a PDCCH. When the terminal receives the information instructing the terminal to use a compressed CBG-based HARQ-ACK, the terminal reduces the original CBG-based HARQ-ACK consisting of N bits to a compressed CBG-based HARQ-ACK consisting of L bits.

[0170] If L is greater than or equal to M, the compressed CBG-based HARQ-ACK is [b 0 , b 1 , …, b M-1 , Y 0 , Y 1 , …, Y L-M-1 In other words, the compressed CBG-based HARQ-ACK is represented as M-bit CBG-based HARQ-ACK[b 0 , b 1 , …, b M-1 ] and the remaining LM bits (ra) [Y 1 , …, Y L-M-1 ]. Therefore, the M-bit CBG-based HARQ-ACK is included in the compressed CBG-based HARQ-ACK as is, and only the remaining bits are reduced from NM to LM. In other words, the M-bit CBG-based HARQ-ACK is stored in the compressed CBG-based HARQ-ACK. In this case, Y m may consist of a fixed value (eg, ACK or NACK) or may be configured based on the value of the M-bit CBG-based HARQ-ACK.

[0171] If L is smaller than M, the compressed CBG-based HARQ-ACK contains [a 0 , a 1 , …, a M-1 In this case, the compressed CBG-based HARQ-ACK is obtained by removing the remaining NM bits from the original CBG-based HARQ-ACK and compressing it to M-bit CBG-based HARQ-ACK [b 0 , b 1 , …, bM-1 ]. According to one embodiment, the compressed CBG-based HARQ-ACK [a 0 , a 1 , …, a M-1 ], k=0~L-2 a k HA k*w , b k*w+1 , …, b (k+1)*w-1 If both are 1 (i.e., ACK), then it is 1 (i.e., ACK), otherwise it is 0 (i.e., NACK). Also, a for k=L-1 k HA k*w , b k*w+1 , …, b M-1 If both are 1 (i.e., ACK), then v is 1 (i.e., ACK), otherwise v is 0 (i.e., NACK). Here, v=floor(M / L).

[0172] For example, assume that N=8, M=4, and the remaining NM bits (i.e., 4 bits) always transmit 0 (i.e., NACK). Also assume that the original CBG-based HARQ-ACK is [10110000]. If a 4-bit compressed CBG-based HARQ-ACK is generated from the original CBG-based HARQ-ACK, the compressed CBG-based HARQ-ACK becomes

[1011] . In other words, the 4-bit CBG-based HARQ-ACK

[1011] is stored in the compressed CBG-based HARQ-ACK even if the payload length is reduced to 4 bits. On the other hand, if a 2-bit compressed CBG-based HARQ-ACK is generated 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 stored in the compressed CBG-based HARQ-ACK. The compressed CBG-based HARQ-ACK

[01] is generated by bundling 2 bits of the 4-bit CBG-based HARQ-ACK

[1011] .

[0173] In the following embodiment, transmission information is assumed in component carrier units. In one embodiment of the present invention, the term "cell" is used as the term "component carrier." In the embodiment of the present invention, for convenience of explanation, the transmission using carrier aggregation is described. However, in the case of a TDD system using carrier aggregation, the component carrier refers to all component carriers of a subframe (or slot) in which the HARQ-ACK is multiplexed. The terminal receives PDSCH(s) from one or more component carrier(s) and generates a HARQ-ACK bit sequence in response thereto. The HARQ-ACK bit sequence is generated by combining HARQ-ACK bit(s) for each component carrier of one or more component carrier(s). In the embodiment of the present invention, the terms HARQ-ACK information bit(s), HARQ-ACK codebook, HARQ-ACK codeword, HARQ-ACK payload, etc. are used. In addition, in the following embodiments, a HARQ-ACK bit sequence for a TB-based transmission (or a PDSCH) is referred to as a TB-based HARQ-ACK bit sequence, and a HARQ-ACK bit sequence for a CBG-based transmission (or a PDSCH) is referred to as a CBG-based HARQ-ACK bit sequence.

[0174] If carrier aggregation is used, each component carrier has a different transmission scheme. That is, the first component carrier has one TB transmission and the second component carrier has two TB transmission. In addition, the 3GPP NR system supports CBG-based transmission together with TB-based transmission as described above. That is, the first component carrier has TB-based transmission and the second component carrier has CBG-based transmission.

[0175] Meanwhile, the terminal monitors the PDCCH on a specific component carrier according to the method configured in the terminal, either self-carrier scheduling or cross-carrier scheduling, and receives the PDSCH based on the information of the PDCCH. In addition, the terminal transmits the HARQ-ACK for the TB transmitted from each component carrier via the PDSCH via the PUCCH (or PUSCH). However, the terminal may fail to decode the PDCCH scheduled on some of the component carriers configured by the base station (i.e., DTX occurs). In this case, the terminal excludes the HARQ-ACK(s) of the corresponding component carrier and transmits only the HARQ-ACK(s) of the successfully decoded component carrier on the PUCCH (or PUSCH). However, if the terminal excludes the transmission of the HARQ-ACK(s) of some component carriers, an error may occur in the interpretation of the HARQ-ACK feedback between the base station and the terminal. To solve this problem, a method of detecting DTX using DAI is used in LTE-A Rel.13.

[0176] FIG. 20 is a diagram showing an example of a DAI value mapped to each component carrier. Referring to FIG. 20, a PDCCH for scheduling each PDSCH includes a counter-DAI (Counter-DAI) and a total-DAI (total). The counter-DAI indicates the cumulative number of PDSCH(s) scheduled from the first component carrier (i.e., component carrier #0) to the current component carrier. The total-DAI indicates the total number of PDSCHs scheduled in all component carriers. If the counter-DAI field consists of A bits, the counter-DAI can range from 0 to 2. A *It has n-1 values ​​(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 is (C-1) mod 2 ASimilarly, if the Total-DAI field consists of B bits, then Total-DAI is set to 0 to 2. B * has m-1 values ​​(where m is a natural number). If the number of PDSCHs scheduled on all component carriers is T, the value of Total-DAI is (T-1) mod 2 B The terminal decodes the PDCCH to identify the order in which the PDSCH was transmitted under the scheduling of the corresponding PDCCH. In this case, the terminal transmits the HARQ-ACK of the PDSCH according to the order in which the corresponding PDSCH was transmitted.

[0177] Referring to FIG. 20, a base station transmits PDSCHs to a terminal that can use up to eight component carriers in a consolidated manner via component carriers #0, #1, #3, #4, #5, and #7. Since the total number of PDSCHs scheduled to the component carriers is six, the value of the total-DAI is set to 5. Thus, the (counter-DAI, total-DAI) values ​​of component carriers #0, #1, #3, #4, #5, and #7 are set to (0, 5), (1, 5), (2, 5), (3, 5), (4, 5), and (5, 5), respectively. If decoding of the PDCCH transmitted via component carrier #3 fails, the terminal identifies that reception of one PUCCH (and reception of one corresponding PDSCH) has failed based on the counter-DAI value of the PDCCH transmitted via component carrier #1 and the counter-DAI value of the PDCCH transmitted via component carrier #4. In addition, if decoding of the PDCCH transmitted via component carrier #7 fails, the terminal identifies, based on the counter-DAI value and total-DAI value of the PDCCH transmitted via component carrier #5, that a PDSCH was scheduled after component carrier #5 but was not successfully received.

[0178] As described above, by using the DAI, the terminal can identify the order of successfully received PDSCHs and the order of unsuccessfully received PDSCHs. However, since the terminal does not know the number of TBs included in the unsuccessfully received PDSCHs, it cannot determine the HARQ-ACK bit sequence. To solve this, two methods are used. The first method is to apply spatial bundling to all PDSCHs. In other words, the 2-bit HARQ-ACK for the PDSCH in which two TBs are transmitted is bundled into 1-bit. This method does not have additional UCI overhead, but the transmittance may be degraded. The second method is to assume that the PDSCH includes two TBs without applying spatial bundling. In other words, in this method, a 2-bit HARQ-ACK is transmitted even for the PDSCH in which one TB is transmitted. This method has the disadvantage of generating additional UCI overhead.

[0179] Meanwhile, as described above, both TB-based transmission and CBG-based transmission are supported in the 3GPP NR system. If the terminal is configured to multiplex and transmit HARQ-ACK bits for multiple component carriers, the base station informs the terminal whether CBG-based transmission is possible for each component carrier. However, TB-based transmission may be performed in the component carriers that configure CBG-based transmission. Thus, the terminal expects only TB-based transmission in a specific component carrier, and expects both TB-based transmission and CBG-based transmission in another specific component carrier. The terminal cannot determine the HARQ-ACK bit sequence to transmit in the uplink unless it successfully receives all PDCCHs scheduled for each component carrier.

[0180] In order to prevent errors in determining and interpreting the HARQ-ACK bit sequence between the base station and the terminal, the above-mentioned DAI is used according to one embodiment of the present invention. Assuming that N HARQ-ACK bits are required in response to a CBG-based transmission, the terminal and the base station use the following three methods to prevent errors in interpreting the HARQ-ACK bit sequence that may occur if decoding of the PDCCH fails.

[0181] According to the first method, if the base station configures CBG-based transmission on at least one component carrier along with carrier aggregation for the terminal, it is assumed that CBG-based transmission is performed for all PDSCHs scheduled for the terminal. That is, even if the base station performs TB-based transmission from a specific component carrier to the terminal, the terminal feeds back an N-bit HARQ-ACK. Here, N is the maximum number of CBGs per TB configured for the terminal. However, the first method has a drawback in that the overhead of the PUCCH is excessively large. For example, if N=4, 1-bit HARQ-ACK increases to 4 bits, which may cause up to 300% overhead.

[0182] According to the second method, if the base station configures the CBG-based transmission on at least one component carrier along with carrier aggregation for the terminal, it is assumed that the TB-based transmission is performed for all PDSCHs scheduled for the terminal. In this case, the terminal is fixed to feed back 1-bit or 2-bit HARQ-ACK in response to the PDSCH. However, in the second method, even if the terminal is configured with CBG-based transmission from the base station and actually performs CBG-based transmission, the performance gain of CBG-based transmission cannot be obtained because the HARQ-ACK feedback information due to the CBG-based transmission cannot be used.

[0183] According to the third method, if the base station configures the UE to perform or not perform CBG-based transmission for each component carrier individually during carrier aggregation, it is assumed that the PDSCH scheduled to the UE performs CBG-based transmission or TB-based transmission according to whether CBG-based transmission is configured for the corresponding component carrier and the DCI for scheduling the PDSCH. That is, if the base station configures the UE to perform CBG-based transmission on a specific component carrier, the UE feeds back an N-bit HARQ-ACK even if the base station performs TB-based transmission from the specific component carrier to the UE. Here, N is the maximum number of CBGs per TB configured for the UE. If the base station does not configure the UE to perform CBG-based transmission from a specific component carrier, the UE is fixed to feed back 1-bit or 2-bit HARQ-ACK assuming that the PDSCH scheduled to the specific component carrier performs TB-based transmission.

[0184] As described above, if both TB-based transmission and CBG-based transmission are configured in a terminal using HARQ-ACK multiplexing, a signaling scheme for preventing an interpretation error of a HARQ-ACK bit sequence between a base station and a terminal is provided. According to an embodiment of the present invention, a terminal receives a PDCCH indicating PDSCH scheduling information of each component carrier from one or more component carriers. The terminal also receives DCI via the PDCCH. At this time, CBG-based transmission is configured in at least one component carrier among one or more component carriers. At least one TB-based transmission and at least one CBG-based transmission are configured in one or more component carriers. The terminal identifies a transmission mode in each component carrier based on a DCI format of the DCI. At this time, the transmission mode is either one of TB-based transmission or CBG-based transmission. Meanwhile, the terminal receives a DAI via a PDCCH. The DAI includes a counter-DAI and a total-DAI as described above.

[0185] The terminal receives the PDSCH of each component carrier from one or more component carriers based on the scheduling information of the PDCCH, and generates a HARQ-ACK bit sequence in response to the reception of the PDSCH of each component carrier. In this case, the terminal generates the HARQ-ACK bit sequence by referring to the DAI. The HARQ-ACK bit sequence includes at least one of a HARQ-ACK bit sequence for a TB-based transmission (i.e., a TB-based HARQ-ACK bit sequence) and a HARQ-ACK bit sequence for a CBG-based transmission (i.e., a CBG-based HARQ-ACK bit sequence). According to an embodiment of the present invention, the DAI is separately applied to the TB-based HARQ-ACK bit sequence and the CBG-based HARQ-ACK bit sequence. In addition, the TB-based HARQ-ACK bit sequence is located before the CBG-based HARQ-ACK bit sequence in the HARQ-ACK bit sequence.

[0186] The UE generates a HARQ-ACK bit sequence for the one or more cell(s) based on the identified transmission mode of each cell. That is, in the HARQ-ACK bit sequence, a TB-based HARQ-ACK bit sequence and a CBG-based HARQ-ACK bit sequence are generated separately. In this case, in the TB-based HARQ-ACK bit sequence, one HARQ-ACK bit is generated per TB, and in the CBG-based HARQ-ACK bit sequence, N HARQ-ACK bit(s) are generated per TB. That is, the HARQ-ACK bit(s) for the CBG-based PDSCH are configured to have the same N bits per TB regardless of the number of CBG(s) actually scheduled and transmitted on the PDSCH.

[0187] According to an embodiment of the present invention, N is the maximum number of CBGs per TB configured in the terminal. According to another embodiment, N is a value configured by the base station for HARQ-ACK multiplexing. According to an additional embodiment, if the number M of CBGs transmitted through a specific component carrier configured with CBG-based transmission in one or more component carriers is less than N, the HARQ-ACK bit(s) for the specific component carrier is configured by repeating the HARQ-ACK bit(s) for the transmitted CBG(s). Also, if the number M of CBGs transmitted through a specific component carrier configured with CBG-based transmission in one or more component carriers is less than N, the HARQ-ACK bit(s) for the specific component carrier is configured with M HARQ-ACK bit(s) and NM NACK(s) for the transmitted CBG(s). The terminal transmits the HARQ-ACK bit sequence thus generated to the base station.

[0188] When the terminal receives a PDCCH, the terminal identifies whether TB-based transmission or CBG-based transmission is applied to the PDSCH for which the PDSCH is scheduled. The terminal identifies the transmission method of each component carrier (i.e., PDSCH) based on information of DCI received through the PDCCH. For example, the transmission method information is signaled as an explicit 1-bit in the DCI or is inferred through a combination of other information included in the DCI. Also, the transmission method of each component carrier is identified based on the DCI format of the DCI. Different DCI formats are used for different transmission methods. Different DCI formats have different information sizes included in the DCI. That is, different DCI formats have different lengths of the DCI payload. Also, in different DCI formats, the CRC is scrambled with different RNTIs. Also, when a PDCCH for scheduling a CBG-based PDSCH is received, the terminal identifies which CCB(s) the corresponding PDSCH is made of among the entire CBG based on information specified in the DCI.

[0189] Hereinafter, with reference to each drawing, a specific embodiment of generating a HARQ-ACK bit sequence in response to receiving a PDSCH will be described. 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 carrier(s) configured by a base station. For example, at least one TB-based transmission and at least one CBG-based transmission are configured in one or more component carrier(s). Also, in the embodiments of each drawing, duplicated descriptions of parts that are the same as or correspond to the embodiments of the previous drawings will be omitted. In the embodiment of the present invention, for convenience of description, it is assumed that each index or counter value increases by 1 from 0. However, the embodiment of the present invention is not limited thereto, and the index or counter value may increase by 1 from a preset value (e.g., 1).

[0190] 21 and 22 are diagrams illustrating a DAI signaling method and a HARQ-ACK bit sequence generating method based thereon according to a first embodiment of the present invention. According to the embodiment of the present invention, the DAI is separately applied to the TB-based HARQ-ACK bit sequence and the CBG-based HARQ-ACK bit sequence. Therefore, the base station generates independent counter-DAI and total-DAI values ​​according to the transmission mode of the PDSCH. The base station transmits the counter-DAI and total-DAI values ​​according to the transmission mode of the PDSCH through the counter-DAI field and total-DAI field of the PDCCH that schedules the corresponding PDSCH. The terminal receives the DCI through the PDCCH transmitted by the base station, distinguishes the transmission mode (TB-based transmission or CBG-based transmission) according to the information of the DCI, and receives the corresponding DAI. The terminal generates a HARQ-ACK bit sequence for the corresponding transmission mode by referring to the received DAI. In this case, the UE interprets the Counter-DAI and Total-DAI received via the PDCCH as the Counter-DAI and Total-DAI for the PDSCH transmission method under PDCCH scheduling, respectively. Table 9 shows how the UE interprets the Counter-DAI and Total-DAI generated according to the first embodiment of the present invention.

[0191] [Table 9]

[0192] Referring to Table 9, the Counter-DAI and Total-DAI fields of the PDCCH that schedules the TB-based PDSCH indicate the Counter-DAI and Total-DAI for the TB-based transmission, respectively, and the Counter-DAI and Total-DAI of the PDCCH that can schedule the CBG-based PDSCH indicate the Counter-DAI and Total-DAI for the CBG-based transmission, respectively.

[0193] First, the counter-DAI for TB-based transmission indicates the cumulative number of TB-based PDSCH(s) scheduled from the first component carrier (i.e., #0) to the previous component carrier. In this case, if the value of the counter-DAI is C, the cumulative number of TB-based PDSCH(s) scheduled to the previous component carrier is C. In the same manner, the counter-DAI for TB-based transmission indicates the cumulative number of TB-based PDSCH(s) scheduled from the first component carrier (i.e., CC#0) to the current component carrier. In this case, if the value of the counter-DAI is C, the cumulative number of TB-based PDSCH(s) scheduled to the current component carrier is C+1. In addition, the total-DAI for TB-based transmission indicates the total number of TB-based PDSCH(s) scheduled to all component carriers. If the value of the total-DAI is T, the total number of TB-based PDSCH(s) scheduled to all component carriers is T+1.

[0194] Next, the counter-DAI for CBG-based transmission indicates the cumulative number of CBG-based PDSCH(s) scheduled from the first component carrier (i.e., #0) to the previous component carrier. In this case, if the value of the counter-DAI is C, the cumulative number of CBG-based PDSCH(s) scheduled to the previous component carrier is C. In the same manner, the counter-DAI for CBG-based transmission indicates the cumulative number of CBG-based PDSCH(s) scheduled from the first component carrier (i.e., CC#0) to the current component carrier. In this case, if the value of the counter-DAI is C, the cumulative number of CBG-based PDSCH(s) scheduled to the current component carrier is C+1. In addition, the total-DAI for CBG-based transmission indicates the total number of CBG-based PDSCH(s) scheduled to all component carriers. If the value of the total-DAI is T, the total number of CBG-based PDSCH(s) scheduled to all component carriers is T+1.

[0195] Fig. 21 is a diagram showing a DAI signaling method according to the first embodiment described above. Referring to Fig. 20, PDSCHs are transmitted to a terminal via component carriers #0, #1, #3, #4, #5, and #7. Among them, CBG-based PDSCHs are transmitted via component carriers #0, #3, #5, and #7, and TB-based PDSCHs are transmitted via component carriers #1 and #4. Since the total number of CBG-based PDSCHs scheduled on all component carriers is 4, the value of the Total-DAI field for CBG-based transmission is set to 3. In addition, the value of the Counter-DAI field for CBG-based transmission is set to a value that increases from 0 based on the cumulative number of CBG-based PDSCHs scheduled up to 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 on which the CBG-based PDSCHs are transmitted are (0, 3), (1, 3), (2, 3), and (3, 3), respectively. Similarly, since the total number of TB-based PDSCHs scheduled on all component carriers is 2, the value of the Total-DAI field for TB-based transmission is set to 1. Also, the value of the Counter-DAI field for TB-based transmission is set to a value that increases from 0 based on the cumulative number of TB-based PDSCH(s) scheduled up to the current component carrier. Therefore, the values ​​of the (Counter-DAI, Total-DAI) fields of the PDCCHs for component carriers #1 and #4 on which the TB-based PDSCHs are transmitted are (0, 1) and (1, 1), respectively.

[0196] The terminal receives a PDCCH for scheduling a PDSCH and identifies the transmission mode of the PDSCH. For example, the terminal identifies the transmission mode of the PDSCH based on the DCI format of the DCI in which the PDCCH is received. In this case, the terminal 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 mode of the PDSCH scheduled by the PDCCH, respectively. For example, in the embodiment of FIG. 21, if a PDCCH for scheduling a PDSCH transmitted via component carrier #3 is received, the terminal identifies that a CBG-based PDSCH is transmitted via carrier #3, and interprets 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 (Counter-DAI, Total-DAI) field value is (1, 3), the terminal identifies that a total of four CBG-based PDSCHs are assigned to all component carriers and that the PDSCH transmitted via component carrier #3 is the second CBG-based PDSCH.

[0197] If the counter-DAI value for CBG-based transmission does not increase sequentially with an increase in component carrier index (i.e., not in the order of 0→1→2→3...), the terminal determines that it has failed to receive some PDCCHs for scheduling CBG-based transmission. Also, if the counter-DAI and total-DAI values ​​of the last PDCCH successfully received among the PDCCHs for scheduling CBG-based transmission are different from each other, the terminal determines that it has failed to receive at least one PDCCH for scheduling CBG-based transmission after the last PDCCH. In this case, the number of PDCCHs for scheduling CBG-based transmissions that have failed to be received after the last PDCCH successfully received is identified by the difference between the total-DAI and counter-DAI values ​​of the last PDCCH. Such a method of interpreting the counter-DAI and total-DAI values ​​is also applicable to the interpretation of the counter-DAI and total-DAI values ​​for TB-based transmission.

[0198] Referring to FIG. 21, the terminal fails to decode the PDCCHs transmitted through component carriers #3 and #7 for which CBG-based transmission is scheduled, and succeeds in decoding the PDCCHs transmitted through the remaining component carriers #0 and #5 for which CBG-based transmission is scheduled. In this case, the terminal receives counter DAI values ​​of 0 and 2 for CBG-based transmission, respectively. Thus, the terminal determines that it has failed to receive the PDCCHs for which counter DAI=1 is among the PDCCHs for which CBG-based transmission is scheduled. Also, a total DAI value of 3 is received for CBG-based transmission, but the counter DAI value of the last PDCCH that was successfully received among the PDCCHs for which CBG-based transmission is scheduled is 2, so the difference between the total DAI value and the counter DAI value of the last PDCCH is 1. Thus, the terminal determines that it has failed to receive one PDCCH for which CBG-based transmission is scheduled after the last PDCCH.

[0199] FIG. 22 is a diagram illustrating a method of generating a HARQ-ACK bit sequence based on a DAI signaled according to the first embodiment described above. According to an embodiment of the present invention, a terminal generates a HARQ-ACK bit sequence for all component carriers in response to receiving a PDSCH of each component carrier. In this case, the terminal generates a HARQ-ACK bit sequence based on an identified transmission scheme of each component carrier. As described above, the HARQ-ACK bit sequence includes a TB-based HARQ-ACK bit sequence and a CBG-based HARQ-ACK bit sequence. In addition, the terminal generates a HARQ-ACK bit sequence by referring to the DAI of a PDCCH that schedules a PDSCH of each component carrier. In this case, the DAI is separately applied to the TB-based HARQ-ACK bit sequence and the CBG-based HARQ-ACK bit sequence.

[0200] More specifically, the UE generates a CBG-based HARQ-ACK bit sequence by combining N-bit HARQ-ACK for each CBG-based transmission in the order of the counter-DAI value of the CBG-based transmission. In the CBG-based HARQ-ACK bit sequence, each bit indicates whether one CBG is successfully received. According to an embodiment of the present invention, in the CBG-based HARQ-ACK bit sequence, N HARQ-ACK bits are generated per TB, where N is the maximum number of CBGs per TB configured in the UE. In addition, the UE generates a TB-based HARQ-ACK bit sequence by combining 1- or 2-bit HARQ-ACK for each TB-based transmission in the order of the counter-DAI value of the TB-based transmission. Incidentally, the HARQ-ACK for the TB-based transmission is configured as 1-bit per PDSCH if spatial bundling is applied, and configured as up to 2-bit per PDSCH if spatial bundling is not applied. In the embodiment of FIG. 22, it is assumed that a 1-bit HARQ-ACK is transmitted as the HARQ-ACK for each TB-based transmission.

[0201] According to an additional embodiment of the present invention, if the terminal does not receive any PDCCH for scheduling CBG-based transmission, the CBG-based HARQ-ACK bit sequence is excluded from the HARQ-ACK bit sequence. That is, the HARQ-ACK bit sequence consists of only the TB-based bit sequence. Similarly, if the terminal does not receive any PDCCH for scheduling TB-based transmission, the TB-based HARQ-ACK bit sequence is excluded from the HARQ-ACK bit sequence. That is, the HARQ-ACK bit sequence consists of only the CBG-based bit sequence. The terminal configures 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 terminal configures the entire HARQ-ACK bit sequence by appending the CBG-based HARQ-ACK bit sequence after the TB-based HARQ-ACK bit sequence. Referring to FIG. 22, the HARQ-ACK bit sequence configured by the terminal is expressed as [x 0 (0) , x 1 (0) , …, x N-1 (0) , x 0 (1) , x 1 (1) , …, x N-1 (1) , x 0 (2) , x 1 (2) , …, x N-1 (2) , x 0 (3) , x1 (3) , …, x N-1 (3) , y 0 (0) , y 0 (1)], where x is the CBG-based HARQ-ACK bit and y is the TB-based HARQ-ACK bit. The superscript indicates the counter-DAI value of the PDCCH that schedules the PDSCH consisting of the corresponding CBG or TB, and the subscript indicates the ascending order of the corresponding CBG or TB in the PDSCH.

[0202] Meanwhile, according to the above-mentioned first embodiment, in order for the terminal to construct the entire HARQ-ACK bit sequence, the terminal should receive at least one DAI for TB-based transmission and at least one DAI for CBG-based transmission. That is, the terminal should receive at least one PDCCH for scheduling CBG-based transmission and at least one PDCCH for scheduling TB-based transmission. If the terminal receives only a PDCCH for one transmission method, scheduling information for other transmission methods cannot be identified. For example, if the terminal does not successfully receive one PDCCH for scheduling TB-based transmission, the terminal does not know whether the PDCCH for TB-based transmission can be transmitted, and therefore does not generate a TB-based HARQ-ACK bit sequence. In this case, an error may occur in the interpretation of the HARQ-ACK bit sequence between the base station and the terminal, and a method for solving this is required.

[0203] Figure 23 is a diagram showing a DAI signaling method according to a second embodiment of the present invention. According to the second embodiment of the present invention, a base station transmits a counter-DAI value according to a transmission method of a PDSCH through a counter-DAI value field of a PDCCH that schedules a corresponding PDSCH, and transmits one of a total-DAI value for TB-based transmission or a total-DAI value for CBG-based transmission through the total-DAI field of the PDCCH based on the counter-DAI value. That is, according to the second embodiment of the present invention, a counter-DAI field signals a counter-DAI value according to a transmission method of a corresponding PDSCH, and a total-DAI field selectively signals a total-DAI value according to a transmission method of a corresponding PDSCH or a total-DAI value according to another transmission method according to the counter-DAI value. According to one embodiment, if the counter-DAI value is an even number, the total-DAI field indicates a total-DAI value according to the transmission method of the corresponding PDSCH, and if the counter-DAI value is an odd number, the total-DAI field indicates a total-DAI value according to another transmission method rather than the transmission method of the corresponding PDSCH.

[0204] The terminal receives DCI via a PDCCH transmitted by a base station, and receives a DAI in the DCI format of the DCI. The terminal generates a HARQ-ACK bit sequence by referring to the received DAI. In this case, the terminal interprets the counter-DAI received via the PDCCH as a counter-DAI for a PDSCH transmission method under PDCCH scheduling. Meanwhile, the terminal identifies whether the total-DAI received via the PDCCH is a total-DAI for TB-based transmission or a total-DAI for TB-based transmission based on the counter-DAI value. Table 10 shows a method for the terminal to interpret the counter-DAI and the total-DAI generated according to the second embodiment of the present invention.

[0205] [Table 10]

[0206] Referring to Table 10, the counter-DAI field of the PDCCH scheduling the TB-based PDSCH indicates the counter-DAI for TB-based transmission, and the counter-DAI field of the PDCCH scheduling the CBG-based PDSCH indicates the counter-DAI for CBG-based transmission. Meanwhile, the total-DAI field of the PDCCH scheduling the TB-based PDSCH indicates the total-DAI for TB-based transmission if the value of the counter-DAI field of the PDCCH is an even number, and indicates the total-DAI for CBG-based transmission if the value of the counter-DAI field of the PDCCH is an odd number. Similarly, the total-DAI field of the PDCCH scheduling the CBG-based PDSCH indicates the total-DAI for CBG-based transmission if the value of the counter-DAI field of the PDCCH is an even number, and indicates the total-DAI for TB-based transmission if the value of the counter-DAI field of the PDCCH is an odd number. Meanwhile, the information indicated by the counter-DAI and total-DAI for the TB-based transmission and the counter-DAI and total-DAI for the CBG-based transmission is the same as that in the first embodiment.

[0207] FIG. 23 is a diagram illustrating a DAI signaling method according to the above-mentioned second embodiment. In the embodiment of FIG. 23, the situation in which the CBG-based PDSCH and the TB-based PDSCH are transmitted through each component carrier is the same as the above-mentioned first embodiment. In this case, the total number of CBG-based PDSCHs scheduled on all component carriers is 4, and the total number of TB-based PDSCHs scheduled on all component carriers is 2. According to the second embodiment, in the DAI for CBG-based transmission, if the counter-DAI value is an even number, the value of the total-DAI field is set to 3, and if the counter-DAI value is an odd number, the value of the total-DAI field is set to 1. Thus, the values ​​of the (counter-DAI, total-DAI) fields of the PDCCH for component carriers #0, #3, #5, and #7 on 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, if the counter-DAI value is an even number, the value of the Total-DAI field is set to 1, and if the counter-DAI value is an odd number, the value of the Total-DAI field is set to 3. Therefore, the values ​​of the (Counter-DAI, Total-DAI) fields of the PDCCH for component carriers #1 and #4 on which the TB-based PDSCH is transmitted are (0, 1) and (1, 3), respectively.

[0208] The terminal receives a PDCCH for scheduling a PDSCH and identifies the transmission mode of the PDSCH. In this case, the terminal interprets the value of the counter-DAI field of the received PDCCH as the counter-DAI for the transmission mode of the PDSCH scheduled by the PDCCH. Meanwhile, when the terminal rescales the value of the total-DAI field of the received PDCCH, if the counter-DAI value is an even number, the terminal interprets it as the total-DAI according to the transmission mode of the corresponding PDSCH, and if the counter-DAI value is an odd number, the terminal interprets it as the total-DAI according to another transmission mode, not the transmission mode of the corresponding PDSCH. For example, in the embodiment of FIG. 23, if a PDCCH for scheduling a PDSCH transmitted via component carrier #3 is received, the terminal identifies that a CBG-based PDSCH is transmitted via 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 an odd number, the UE interprets 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 UE recognizes that the PDSCH transmitted over component carrier #3 is the second CBG-based PDSCH and that a total of two TB-based PDSCHs are allocated to all component carriers.

[0209] The method of determining that the UE has failed to receive the PDCCH for scheduling the CBG-based transmission or the TB-based transmission based on the counter-DAI and / or the total-DAI is similar to that of the first embodiment described above. However, in order to obtain the total-DAI for a specific transmission scheme, the UE should refer to the total-DAI field in the PDCCH when the counter-DAI field value is an even number. Therefore, in the first embodiment described above, the total-DAI value of the last PDCCH should be switched to the total-DAI value of the PDCCH when the counter-DAI field value is an even number. Meanwhile, in order to obtain the total-DAI for a specific transmission scheme, the UE refers to the total-DAI field from the PDCCH for scheduling the PDSCH of another transmission scheme when the counter-DAI field value is an odd number. The UE determines whether or not the UE has failed to receive at least some of the PDCCHs by referring to the total-DAI for the transmission scheme obtained in this way.

[0210] Meanwhile, according to the above-mentioned second embodiment, even if the terminal receives only the PDCCH that schedules the PDSCH of one transmission method, it can know the number of PDSCHs scheduled for other transmission methods. Therefore, even if the reception of all PDCCHs that schedule the PDSCHs of a specific transmission method fails, it is possible to prevent an error in interpretation of the HARQ-ACK bit sequence between the base station and the terminal. For example, even if one PDCCH that schedules TB-based transmission is transmitted and the terminal fails to receive the corresponding PDCCH, the terminal can identify the number of scheduled TB-based PDSCHs through the PDCCH that schedules CBG-based transmission. However, in a situation where only one PDCCH is successfully received, an error in interpretation of the HARQ-ACK bit sequence between the base station and the terminal may still occur.

[0211] FIG. 24 is a diagram illustrating a DAI signaling method according to a third embodiment of the present invention. According to the third embodiment of the present invention, a base station generates independent counter-DAIs for TB-based transmission and CBG-based transmission, and generates a common total-DAI to be used for both the two transmission methods. The base station transmits a counter-DAI value according to the transmission method of the PDSCH through the counter-DAI field of the PDCCH that schedules the corresponding PDSCH, and transmits a common total-DAI value through the total-DAI fields of all the PDCCHs. That is, according to the third embodiment of the present invention, the counter-DAI field signals a counter-DAI value according to the transmission method of the corresponding PDSCH, but the total-DAI field signals only one of the total-DAI value for the TB-based transmission and the total-DAI value for the CBG-based transmission. The terminal interprets the counter-DAI received through the PDCCH as the counter-DAI for the transmission method of the PDSCH scheduled by the PDCCH. In addition, the terminal interprets the total-DAI received via the PDCCH as a total-DAI commonly applied to all transmission methods. Table 11 shows how the terminal interprets the counter-DAI and the total-DAI generated according to the third embodiment of the present invention.

[0212] [Table 11]

[0213] Referring to Table 11, the information indicated by the counter-DAI field of the PDCCH scheduling the TB-based PDSCH and the counter-DAI field of the PDCCH scheduling the CBG-based transmission are the same as those in the first and second embodiments. However, the total-DAI field of the PDCCH scheduling the TB-based PDSCH and the total-DAI field of the PDCCH scheduling the CBG-based PDSCH both indicate a common total-DAI. The common total-DAI value is determined according to various embodiments. If at least one TB-based PDSCH and at least one CBG-based PDSCH are both scheduled in the entire component carriers, the common total-DAI value indicates the total number of PDSCHs of any one transmission method scheduled in the entire component carriers. According to one embodiment, the common total-DAI value indicates the total number of CBG-based PDSCHs scheduled in the entire component carriers. According to another embodiment, the common total-DAI value is determined to a value that minimizes the length of the HARQ-ACK bit sequence. If only one PDSCH of a transmission mode is scheduled in the entire component carrier, a common Total-DAI value is determined to be a preset value. According to an embodiment of the present invention, if a 2-bit Total-DAI is used, the preset value is a binary number "11". Also, if a 3-bit Total-DAI is used, the preset value is "011" or "111".

[0214] FIG. 24 is a diagram illustrating a DAI signaling method according to the above-mentioned third embodiment. In the embodiment of FIG. 24, the situation in which the CBG-based PDSCH and the TB-based PDSCH are transmitted through each component carrier is the same as that of the above-mentioned first embodiment. According to one embodiment, if a common Total-DAI value indicates the total number of CBG-based PDSCHs, the Total-DAI field for CBG-based transmission and the Total-DAI field for TB-based transmission are both set to 3. Thus, the values ​​of the (Counter-DAI, Total-DAI) field of the PDCCH for component carriers #0, #3, #5, and #7 on 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) field of the PDCCH for component carriers #1 and #4 on which the TB-based PDSCH is transmitted are (0, 3) and (1, 3), respectively.

[0215] The terminal receives a PDCCH for scheduling a PDSCH and identifies the transmission mode of the PDSCH. In this case, the terminal interprets the value of the counter-DAI field of the received PDCCH as the counter-DAI for the transmission mode of the PDSCH scheduled by the PDCCH. Meanwhile, the terminal interprets the value of the total-DAI field of the received PDCCH as the total-DAI applied to both the CBG-based transmission and the TB-based transmission. For example, in the embodiment of FIG. 24, if a PDCCH for scheduling a PDSCH transmitted via component carrier #3 is received, the terminal identifies that the CBG-based PDSCH is transmitted via carrier #3, and interprets the values ​​of the counter-DAI fields of the PDCCH as the counter-DAI for the CBG-based transmission. Also, the terminal interprets the value of the total-DAI field of the PDCCH as the total-DAI applied to both the CBG-based transmission and the TB-based transmission. Since the received (Counter-DAI, Total-DAI) field value is (1, 3), the terminal recognizes that the PDSCH transmitted over component carrier #3 is the second CBG-based PDSCH and that four CBG-based PDSCHs and four TB-based PDSCHs are allocated to all component carriers. Meanwhile, although the Total-DAI field for CBG-based transmission and the Total-DAI field for TB-based transmission both signal a common Total-DAI value, the total numbers of scheduled CBG-based PDSCHs and TB-based PDSCHs may not be the same. In other words, if the Total-DAI field consists of B bits and signals a common Total-DAI value k, the total number of scheduled CBG-based PDSCHs is 2 B *n+k+1, and the total number of scheduled TB-based PDSCHs is 2 B *m+k+1, where n and m are non-negative integers. Therefore, if the Total-DAI field consists of two bits, the difference between the total number of scheduled CBG-based PDSCHs and the total number of scheduled TB-based PDSCHs is a multiple of 4.

[0216] The method of determining that the UE has failed to receive the PDCCH for scheduling the CBG-based transmission or the TB-based transmission based on the counter-DAI and / or the total-DAI is similar to that of the first embodiment described above. However, if the received common total-DAI indicates a preset value and the PDCCH for scheduling the PDSCH of a specific transmission scheme is not received at all, the UE determines that the PDSCH of the specific transmission scheme is not scheduled. When generating a HARQ-ACK bit sequence, the UE does not multiplex the HARQ-ACK bit sequence for the specific transmission scheme that is determined to be not scheduled. For example, if the common total-DAI indicates a preset value and the PDCCH for scheduling the TB-based transmission is not received at all, the HARQ-ACK bit sequence generated by the UE is configured by excluding the TB-based HARQ-ACK bit sequence. Similarly, if the common Total-DAI indicates a preset value and no PDCCH for scheduling CBG-based transmission is received, the HARQ-ACK bit sequence generated by the terminal is configured excluding the CBG-based HARQ-ACK bit sequence. On the other hand, if no PDCCH for scheduling PDSCH of a specific transmission method is received but the common Total-DAI does not indicate a preset value, the terminal determines that the PDSCH of the specific transmission method has been scheduled but has failed to receive the corresponding PDSCH. Therefore, when the terminal generates the HARQ-ACK bit sequence, it multiplexes the HARQ-ACK bit sequence for the corresponding transmission method. According to an embodiment of the present invention, if a 2-bit Total-DAI is used, the preset value is a binary number "11". Also, if a 3-bit Total-DAI is used, the preset value is "011" or "111". Furthermore, according to an embodiment of the present invention, the method of not multiplexing the HARQ-ACK bit sequence for a specific transmission scheme is applied only when the HARQ-ACK bit sequence is transmitted via the PUSCH.In other words, if the common total-DAI indicates a preset value, a PDCCH scheduling a PDSCH of a specific transmission method is not received at all, and a HARQ-ACK bit sequence is transmitted via a PUSCH, the terminal does not multiplex the HARQ-ACK bit sequence for the specific transmission method.

[0217] Meanwhile, according to the third embodiment of the present invention, a mismatch may occur in the total-DAI for a specific transmission scheme since a common total-DAI is used. Therefore, in the case of a specific transmission scheme, the terminal generates a HARQ-ACK bit sequence based on total number information according to a common total-DAI value, which is different from the total number of PDSCHs scheduled in the specific transmission scheme. For example, if the terminal successfully decodes the PDCCHs transmitted through component carriers #1 and #4 scheduled for TB-based transmission, the terminal receives values ​​of 0 and 1 as the counter-DAI for the TB-based transmission, respectively. Meanwhile, the terminal receives a value of 3 as the total-DAI for the TB-based transmission. Although the total-DAI value for the TB-based transmission is 3, the counter-DAI value of the last PDCCH successfully received among the PDCCHs scheduling the TB-based transmission is 1, so the difference between the total-DAI value of the last PDCCH and the counter-DAI value is 2. Therefore, the terminal determines that it has failed to receive two PDCCHs scheduling the TB-based transmission after the last PDCCH. Therefore, the UE transmits a NACK as a HARQ-ACK for the PDSCH scheduled by the PDCCH identified as having failed reception. Meanwhile, the base station ignores the NACK transmitted due to the mismatch because it counts the actual total number of scheduled TB-based PDSCHs differently from the common total-DAI value.

[0218] 25 and 26 are diagrams illustrating an embodiment of generating a HARQ-ACK bit sequence based on a DAI signaled according to the third embodiment described above. FIG. 25 illustrates an embodiment in which a common total-DAI value indicates the total number of CBG-based PDSCHs, and FIG. 26 illustrates an embodiment in which a common total-DAI value indicates the total number of TB-based PDSCHs. A method of generating a HARQ-ACK bit sequence based on a DAI signaled according to the third embodiment of the present invention is similar to the first embodiment described with reference to FIG. 22. However, if the common total-DAI indicates a preset value and no PDCCH scheduling a PDSCH of a specific transmission scheme is received, the UE does not multiplex the HARQ-ACK bit sequence for the specific transmission scheme when generating the HARQ-ACK bit sequence.

[0219] First, referring to FIG. 25, a 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 is composed of 2 bits, the total number of CBG-based PDSCHs scheduled on all component carriers is 2. 2 *n+3+1=4*(n+1), and the total number of TB-based PDSCHs scheduled on all component carriers is 2 2 *m+3+1=4*(m+1), where n and m are non-negative integers. The UE generates a CBG-based HARQ-ACK bit sequence and a TB-based HARQ-ACK bit sequence, and combines the two HARQ-ACK bit sequences to form an entire HARQ-ACK bit sequence. According to the embodiment of FIG. 25, since the value of the Total-DAI field is 3, the TB-based HARQ-ACK bit sequence includes HARQ-ACK[y] for the virtual TB-based PDSCH (i.e., PDSCH TB-tx #2, #3) in addition to the two TB-based PDSCHs (i.e., PDSCH TB-tx #0, #1). 0 (2) , y 0 (3)] is added. Here, the virtual PDSCH means a PDSCH that is not actually transmitted. The UE appends the CBG-based HARQ-ACK bit sequence to the TB-based HARQ-ACK bit sequence to configure the entire HARQ-ACK bit sequence. Referring to FIG. 25, the HARQ-ACK bit sequence configured by the UE is [x 0 (0) , x 1 (0) , …, x N-1 (0) , x 0 (1) , x 1 (1) , …, x N-1 (1) , x 0 (2) , x 1 (2) , …, x N-1 (2) , x 0 (3) , x 1 (3) , …, x N-1 (3) , y 0 (0) , y 0 (1) , y 0 (2) , y 0 (3) ], where the last two bits of the TB-based HARQ-ACK bit sequence [y 0 (2) , y 0 (3) ] is a dummy bit having unnecessary information, intended to prevent interpretation errors of the HARQ-ACK bit sequence between the base station and the terminal.

[0220] Next, referring to FIG. 26, a common Total-DAI value indicates the total number of TB-based PDSCHs, and the value of the Total-DAI field is 3. If the Total-DAI field is composed of 2 bits, the total number of CBG-based PDSCHs scheduled on all component carriers is 2. 2*n+1+1=4*n+2, and the total number of TB-based PDSCHs scheduled on all component carriers is 2 2 *m+1+1=4*m+2 (where n and m are non-negative integers). The UE generates a CBG-based HARQ-ACK bit sequence and a TB-based HARQ-ACK bit sequence, and combines the two HARQ-ACK bit sequences to form an entire HARQ-ACK bit sequence. According to the embodiment of FIG. 26, since the value of the Total-DAI field is 1, the TB-based HARQ-ACK bit sequence includes HARQ-ACK[x 0 (4) , x 1 (4) , …, x N-1 (4) , x 0 (5) , x 1 (5) , …, x N-1 (5) ] is added. The UE appends the CBG-based HARQ-ACK bit sequence to the TB-based HARQ-ACK bit sequence to construct the entire HARQ-ACK bit sequence. Referring to FIG. 26, the HARQ-ACK bit sequence constructed by the UE is [x 0 (0) , x 1 (0) , …, x N-1 (0) , x 0 (1) , x 1 (1) , …, x N-1 (1) , x 0 (2) , x 1 (2) , …, x N-1 (2) , x 0 (3) , x 1 (3) , …, x N-1(3) , x 0 (4) , x 1 (4) , …, x N-1 (4) , x 0 (5) , x 1 (5) , …, x N-1 (5) , y 0 (0) , y 0 (1) ], where the last 2N bits of the CBG-based HARQ-ACK bit sequence [x 0 (4) , x 1 (4) , …, x N-1 (4) , x 0 (5) , x 1 (5) , …, x N-1 (5) ] is a dummy bit having unnecessary information, intended to prevent interpretation errors of the HARQ-ACK bit sequence between the base station and the terminal.

[0221] FIG. 27 illustrates another embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled according to the third embodiment. As described above, according to the additional embodiment of the present invention, only the PDSCH of one of the transmission methods of CBG-based transmission and TB-based transmission is scheduled. In this case, the total-DAI value is set to a preset value 3 (i.e., binary '11') to signal that only the PDSCH of one of the transmission methods is scheduled. Also, in the embodiment of FIG. 27, it is assumed that the TB-based PDSCH is transmitted via component carriers #1 and #4, and the CBG-based PDSCH is not scheduled.

[0222] First, FIG. 27(a) shows an example in which the value of the Total-DAI field indicates the total number of TB-based PDSCHs. Since the total number of TB-based PDSCHs scheduled on all component carriers is 2, the value of Total-DAI is set to 1. In this case, the total number of CBG-based PDSCHs scheduled on all component carriers is interpreted as 2. Therefore, the UE receives 2*N-bit HARQ-ACK[x 0 (0) , x 1 (0) , …, x N-1 (0) , x 0 (1) , x 1 (1) , …, x N-1 (1) Since the terminal detects only the PDCCH that schedules the TB-based PDSCH, the 2*N-bit HARQ-ACKs are dummy bits and are all set to NACK.

[0223] Next, FIG. 27(b) shows an embodiment in which the value of the Total-DAI field indicates a preset value indicating that a PDSCH of a specific transmission scheme is not scheduled. Here, the preset value is 3 (i.e., binary '11'). Since the received Total-DAI indicates the preset value and no PDCCH for scheduling the CBG-based PDSCH is received, the UE determines that the CBG-based PDSCH is not scheduled. Therefore, the UE generates an entire HARQ-ACK bit sequence including only the TB-based HARQ-ACK bit sequence, excluding the CBG-based HARQ-ACK bit sequence. Here, since the value of the Total-DAI field is 3, the UE interprets that the total number of TB-based PDSCHs scheduled on all component carriers is 4. However, since the UE actually receives two TB-based PDSCHs, the UE generates 2-bit HARQ-ACK[y 0 (2) , y0 (3) Since the terminal cannot receive a PDCCH that schedules a virtual TB-based PDSCH, the 2-bit HARQ-ACK is a dummy bit and both bits are set to NACK.

[0224] Meanwhile, in the above embodiment, it is assumed that one HARQ-ACK bit is generated per TB in the TB-based HARQ-ACK bit sequence, and N HARQ-ACK bit(s) are generated per TB in the CBG-based HARQ-ACK bit sequence. In the following embodiment, it is assumed that one HARQ-ACK bit(s) from 1 to N is generated per TB in the CBG-based HARQ-ACK bit sequence. For example, the length of the HARQ-ACK bit(s) for the CBG-based PDSCH is determined based on the number of CBG(s) actually scheduled and transmitted in the PDSCH. In addition, in the following embodiment, it is assumed that the TB-based transmission is one CBG-based transmission. That is, it is assumed that a PDSCH consisting of one TB is a PDSCH consisting of one CBG, and a PDSCH consisting of two TBs is a PDSCH consisting of two CBGs, and the respective embodiments are described. Therefore, the separate expressions TB-based transmission or CBG-based transmission can be omitted. Incidentally, the terminal identifies whether TB-based transmission or CBG-based transmission is applied to the PDSCH to which the PDSCH is scheduled, based on information in the PDCCH.

[0225] FIG. 28 is a diagram illustrating a DAI signaling method according to a fourth embodiment of the present invention. According to the fourth embodiment of the present invention, a base station generates a counter-DAI value and a total-DAI value based on the number of scheduled CBGs, and transmits them through a counter-DAI field and a total-DAI field. That is, the counter-DAI indicates the cumulative number of scheduled CBG(s) from the first component carrier (i.e., component carrier #0) to the previous component carrier. Also, the total-DAI indicates the total number of scheduled CBGs in all component carriers. Referring to FIG. 28, a PDSCH is transmitted to a terminal through component carriers #0, #1, #3, #4, #5, and #7. In this case, the number of CBG(s) transmitted through component carriers #0, #1, #3, #4, #5, and #7 is 2, 3, 1, 4, 3, and 3, respectively. Since the total number of CBGs scheduled on all component carriers is 16, the values ​​of the (Counter-DAI, Total-DAI) fields of each PDCCH for component carriers #0, #1, #3, #4, #5, and #7 are (0, 16), (2, 16), (5, 16), (6, 16), (10, 16), and (13, 16), respectively.

[0226] When the terminal receives a PDCCH, the terminal identifies the number of CBGs included in the PDSCH scheduled by the PDCCH through the CBG scheduling information included in the PDCCH. In addition, the terminal identifies the total number of CBGs scheduled on all component carriers through the Total-DAI value, and identifies 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 includes k CBG(s) and the value of the (Counter-DAI, Total-DAI) field is (C, T), the PDSCH scheduled on all component carriers includes a total of T CBGs, and the CBG(s) included in the PDSCH scheduled by the current PDCCH are the C+1th to C+kth CBG(s) of the total T CBGs. For example, if the terminal successfully receives a PDCCH that schedules a PDSCH transmitted via component carrier #3, the terminal knows that the PDSCH transmitted via component carrier #3 includes one CBG based on the scheduling information included in the PDCCH. In addition, the terminal identifies via the received (Counter-DAI, Total-DAI) field value (5, 16) that a total of 16 CBGs are scheduled across all component carriers, and that the CBG included in the PDSCH transmitted via component carrier #3 is the sixth CBG among the total of 16 CBGs.

[0227] The terminal generates the HARQ-ACK bit sequence in the following manner. First, the length of the HARQ-ACK bit sequence is 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 is 2× B*n+T, where n is a non-negative integer and is the minimum value that allows the HARQ-ACK bit for the CBG included in the PDSCH scheduled by the successfully received PDCCH to be included in the HARQ-ACK bit sequence. The UE determines the position of the HARQ-ACK bit(s) for the CBG scheduled by the corresponding PDCCH based on the counter-DAI value acquired from the successfully received PDCCH and the number k of scheduled CBG(s). That is, if the value of the counter-DAI field is C, the positions of the HARQ-ACK bit(s) in the HARQ-ACK bit sequence are from C+1 to C+k. If the counter-DAI field consists of A bits and the value of the counter-DAI field is C, the possible positions of the HARQ-ACK bit(s) are 2 A *m+C+2 from the first A *m+C+kth bits, where m is a non-negative integer. Meanwhile, bits in the HARQ-ACK bit sequence that are not mapped to a HARQ-ACK bit(s) are set to NACK.

[0228] Meanwhile, according to the above-mentioned fourth embodiment, when the terminal successfully receives the PDCCH, the total number of CBGs scheduled in all component carriers and the transmission order of the CBGs included in the PDSCH scheduled by the corresponding PDCCH are identified. However, since various numbers of CBGs are transmitted through one PDSCH, when the terminal identifies the reception failure of multiple CBGs, it is not possible to identify how many PDSCHs have failed to be received.

[0229] Figure 29 is a diagram showing a DAI signaling method according to a fifth embodiment of the present invention. According to the fifth embodiment of the present invention, a 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 transmits the generated DAI values ​​via a first counter-DAI field, a first total-DAI field, a second counter-DAI field, and a second total-DAI field, respectively.

[0230] First, the first counter-DAI indicates the cumulative number of PDSCH(s) scheduled from the first component carrier (i.e., component carrier #0) to the previous component carrier. In this case, if the value of the first counter-DAI is C, the cumulative number of PDSCH(s) scheduled to the previous component carrier is C (i.e., the cumulative number of PDSCH(s) scheduled to the current component carrier is C+1). Also, the first total-DAI indicates the total number of PDSCH(s) scheduled to all component carriers. If the value of the first total-DAI is T, the total number of PDSCH(s) scheduled to all component carriers is T+1.

[0231] Next, the second Counter-DAI indicates the cumulative number of CBG(s) scheduled from the first component carrier (i.e., component carrier #0) to the previous component carrier. Also, the second Total-DAI is determined based on the total number of CBGs scheduled to the entire component carrier. 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 are set by subtracting the values ​​of the first Counter-DAI field and the first Total-DAI field from the information for signaling. For example, if the number of CBGs scheduled to the previous component carrier is P and the first Counter-DAI value scheduled to the current component carrier is C1, the second Counter-DAI value C2 of the current component carrier is set to C2=P-C1. Also, if the number of CBGs scheduled to the entire component carrier is Q and the first Total-DAI value is T1, the second Total-DAI value T2 is set to T2=Q-T1.

[0232] In the embodiment of Fig. 29, the situation in which the CBG(s) are transmitted through each component carrier is the same as in the above-mentioned fourth embodiment. In this case, the values ​​of the (1st Counter-DAI, 1st Total-DAI, 2nd Counter-DAI, 2nd Total-DAI) fields of each PDCCH for component carriers #0, #1, #3, #4, #5, and #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).

[0233] When the terminal receives a PDCCH, the terminal identifies the number of CBGs included in the PDSCH scheduled by the PDCCH through CBG scheduling information included in the PDCCH. Also, the terminal identifies the total number of PDSCHs scheduled on all component carriers through a first total-DAI value, and identifies the transmission order of CBGs included in the PDSCH scheduled by the corresponding PDSCH through a first counter-DAI value. In addition, the terminal identifies the total number of CBGs scheduled on all component carriers through a second total-DAI value, and identifies the transmission order of 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 (1st Counter-DAI, 1st Total-DAI, 2nd Counter-DAI, 2nd Total-DAI) field values ​​are (C1, T1, C2, T2), the total number of PDSCHs scheduled on all component carriers is T1+1, and the total number of scheduled CBGs is T1+T2. Also, the order of the PDSCH scheduled by the current PDCCH is C1, and the CBGs included in the PDSCH are C1+C2+1 to C1+C2+k CBGs out of a total of T1+T2 CBGs.

[0234] If the first counter-DAI value does not increase sequentially with an increase in component carrier index (i.e., not in the order of 0→1→2→3...), the terminal determines that some PDCCHs have been unsuccessfully received. Also, if the first counter-DAI value and the first total-DAI value of the last successfully received PDCCH are not the same, the terminal determines that at least one PDCCH has been unsuccessfully received after the last PDCCH. In this case, the number of PDCCHs that have been unsuccessfully received after the last successfully received PDCCH is identified by the difference between the first total-DAI value and the first counter-DAI value of the last PDCCH.

[0235] The terminal generates the HARQ-ACK bit sequence in the following manner. First, the length of the HARQ-ACK bit sequence is determined based on the sum of the first total-DAI value and the second total-DAI value. The terminal determines the position of the HARQ-ACK bit(s) for the CBG scheduled by the corresponding PDCCH based on the first counter-DAI value, the second counter-DAI value acquired from the successfully received PDCCH, and the number k of scheduled CBG(s). That is, if the value of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) field is (C1, T1, C2, T2), the position of the HARQ-ACK bit(s) in the HARQ-ACK bit sequence is from C1+C2+1th to C1+C2+kth. Meanwhile, the bits in the HARQ-ACK bit sequence to which the HARQ-ACK bit(s) is not mapped are set to NACK.

[0236] Meanwhile, according to the above-mentioned fifth embodiment, if the terminal successfully receives the PDCCH, the total number of CBGs scheduled in all component carriers and the transmission order of the CBGs included in the PDSCH scheduled by the corresponding PDCCH are identified. Also, if the terminal fails to receive at least one PDSCH, it can identify which PDSCH failed to receive. However, according to this embodiment, there is a drawback in that the DCI overhead is high.

[0237] 30 is a diagram illustrating a DAI signaling method according to a sixth embodiment of the present invention. According to the sixth embodiment of the present invention, a 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 transmits the generated DAI values ​​via a first counter-DAI field, a first total-DAI field, and a second counter-DAI field, respectively.

[0238] In the sixth embodiment of the present invention, the definitions of the first total-DAI and the first total-DAI are the same as those in the fifth embodiment described above. However, the second counter-DAI is determined based on the number of CBG(s) scheduled for K PDSCH(s) before the current component carrier. According to an embodiment of the present invention, the K PDSCHs before the current component carrier are 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 include the k PDSCHs from the first component carrier to the previous component carrier and the K - k PDSCHs in reverse order up to the last component carrier. According to one embodiment, the value of K is determined based on the value of the first total-DAI, that is, the total number of CBGs scheduled for all component carriers. For example, if the value of the first total-DAI is 1, 2, or 3 respectively, the value of K is set to 0, 1, or 2. Also, if the value of the first total-DAI is greater than 3, the value of K is 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 is set by subtracting K from the number of CBG(s) scheduled for K PDSCH(s) before the current component carrier.

[0239] In the embodiment of FIG. 30, the situation where CBG(s) are transmitted via each component carrier is the same as that in the fourth embodiment described above. At this time, the value of K is set to 3, and the values of the (first counter-DAI, first total-DAI, second counter-DAI) fields of each PDCCH for component carriers #0, #1, #3, #4, #5, and #7 are (0, 5, 7), (1, 5, 5), (2, 5, 5), (3, 5, 3), (4, 5, 5), and (5, 5, 5).

[0240] The method of determining that the terminal has failed to receive some PDCCHs is the same as that of the fifth embodiment described above. In addition, in the sixth embodiment, the second counter-DAI is determined based on the number of CBG(s) scheduled for K PDSCH(s) before the current component carrier, so that the terminal identifies the number of CBG(s) included in the PDSCH scheduled by the PDCCH that has failed to be received based on the second counter-DAI. For example, assume that the terminal has failed to receive a PDCCH with a first counter-DAI value of 2 and has successfully received the remaining PDCCHs. Since the first counter-DAI value of the successfully received PDCCH does not have a value of 2, the terminal identifies that the terminal has failed to receive a PDCCH with a first counter-DAI value of 2. The number of CBG(s) included in the PDSCH scheduled by the PDCCH with the first counter-DAI value of 2 is identified based on the value obtained by subtracting the number of CBGs included in the PDSCH scheduled by the PDCCH with the first counter-DAI value of 0 and 1, respectively, from the second counter-DAI value of the PDCCH with the first counter-DAI value of 3. In the embodiment of FIG. 30, the second counter-DAI value of the PDCCH with the first counter-DAI value of 3 is 3, and the number of CBGs included in the PDSCH scheduled by the PDCCH with the first counter-DAI value of 0 and 1, respectively, are 2 and 3. Therefore, the number x of CBGs included in the PDSCH scheduled by the PDCCH with the first counter-DAI value of 2 satisfies (2+3+x)-K=3. Here, since K is 3, the terminal identifies that x is 1.

[0241] FIG. 31 is a diagram illustrating an embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled according to the sixth embodiment described above. As in the above embodiment, the terminal identifies the number of PDSCHs transmitted through the component carrier based on the value of the first counter-DAI and the value of the first total-DAI. Also, the terminal identifies the number of CBGs transmitted through each through the second counter-DAI value. Thus, the terminal generates a HARQ-ACK bit sequence by combining HARQ-ACK bits for PDSCHs scheduled by the corresponding PDCCH while sequentially increasing the value of the first total-DAI field from 0 to the first total-DAI value. However, if the value of K is 2 or more (for example, K=2 or 3), the terminal generates a HARQ-ACK bit sequence by combining HARQ-ACK bits for PDSCHs scheduled by the corresponding PDCCH while cyclically increasing the value of the first total-DAI field from i. In this case, a header indicating configuration information of the HARQ-ACK bit sequence is added to the beginning or end of the HARQ-ACK bit sequence to indicate the value of i. That is, the HARQ-ACK bit sequence includes a header and a main bit sequence. The header indicates information regarding which HARQ-ACK bit for the PDSCH the main bit sequence starts from.

[0242] Referring to FIG. 31, if the value of K is 2 or 3, there are four candidates for the HARQ-ACK bit sequence transmitted by the terminal. Thus, the header is composed of two bits, and indicates from which HARQ-ACK bit for which PDSCH the main bit sequence starts. 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 bit of the second, third, or fourth PDSCH, respectively.

[0243] Meanwhile, according to the above-mentioned sixth embodiment, if the terminal successfully receives the PDCCH, the total number of PDSCHs scheduled on all component carriers and the order in which the PDSCHs scheduled by the corresponding PDCCH are transmitted are identified. In addition, the terminal identifies information regarding the number of CBGs through the second counter-DAI value. According to the sixth embodiment, the second total-DAI field is not transmitted, so that the overhead of DCI signaling can be reduced compared to the fifth embodiment, but the overhead of UCI transmission increases because a header must be added to the HARQ-ACK bit sequence transmitted by the terminal.

[0244] 32 is a diagram illustrating a DAI signaling method according to a seventh embodiment of the present invention. According to the seventh embodiment of the present invention, the base station divides the transmission type into a first type transmission and a second type transmission according to the number of CBGs included in the scheduled PDSCH, and generates a first counter-DAI (i.e., counter-DAI#1) and a first total-DAI (i.e., total-DAI#1) value based on the number of PDSCHs 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 CBGs for each transmission type. The base station transmits the DAI value of the same type as the transmission type of the PDSCH scheduled by the PDCCH through the first counter-DAI field, the first total-DAI field, the second counter-DAI field, and the second total-DAI field of the PDCCH, respectively. When the terminal receives the PDCCH, the terminal identifies the number of CBGs included in the PDSCH scheduled by the PDCCH through the CBG scheduling information included in the PDCCH. In addition, the terminal identifies a transmission type of the corresponding PDSCH based on the number of CBGs included in the PDSCH, and 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 via the PDCCH as DAI values ​​for the identified transmission type.

[0245] According to an embodiment of the present invention, the first type transmission is a transmission of a PDSCH having a CBG of a preset number or less, and the second type transmission is a transmission of a PDSCH having a CBG of more than the preset number.

[0246]

number

number

number

number

number

[0247] The DAI value for the first type transmission is applied to the PDSCH and CBG based on the first type transmission, and the definition of the DAI value is the same as in the above-mentioned fifth embodiment. Similarly, the DAI value for the second type transmission is applied to the PDSCH and CBG based on the second type transmission. However, in the DAI for the second type transmission, the first counter-DAI and the first total-DAI are set in the same way as in the above-mentioned fifth embodiment, but the second counter-DAI and the second total-DAI are set to have a different granularity than that in the above-mentioned fifth embodiment. In other words, the maximum number of minimum CBGs included in the PDSCH in which the second type transmission is performed is

number

number

number

[0248] Referring to FIG. 32, PDSCH is transmitted to the terminal via component carriers #0, #1, #3, #4, #5, and #7. In this case, the number of CBG(s) transmitted via component carriers #0, #1, #3, #4, #5, and #7 is 2, 3, 1, 4, 3, and 4, respectively. If N=4, the PDSCH scheduled to component carriers #0 and #3 is a PDSCH based on the first type transmission, and the PDSCH scheduled to component carriers #1, #4, #5, and #7 is a PDSCH based on the second type 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 on which the PDSCH based on the first type transmission is scheduled are (0, 1, 0, 1) and (1, 1, 1, 1), respectively. Also, the values ​​of the (1st Counter-DAI, 1st Total-DAI, 2nd Counter-DAI, 2nd Total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7 on which a PDSCH based on the 2nd type transmission is scheduled are (0, 3, 0, 2), (1, 3, 0, 2), (2, 3, 1, 2), and (3, 3, 1, 2), respectively. Table 12 shows how the terminal interprets the Counter-DAI and Total-DAI generated according to the seventh embodiment of the present invention.

[0249] [Table 12]

[0250] Referring to Table 12, the UE identifies the number of PDSCHs of the corresponding transmission type scheduled on 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. Also, the UE identifies the number of CBGs included in the PDSCHs of the corresponding transmission type scheduled on the component carrier and the transmission order of the CBGs included in 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. If the PDSCH scheduled by the current PDCCH includes k CBGs, the transmission type is x (where x=1 or 2), and the values ​​of the (1st counter-DAI, 1st total-DAI, 2nd counter-DAI, 2nd total-DAI) fields are (C1, T1, C2, T2), the total number of PDSCHs based on type-x transmission scheduled on all component carriers is T1+1, and the order of the PDSCHs based on type-x transmission scheduled by the current PDCCH is C1+1. Also, the CBGs included in the PDSCH based on type-x are M x *C1+C2+1st to M x *C1+C2+kth CBG. Here, if x=1, then M x =1, and if x=2

number

[0251] FIG. 33 is a diagram illustrating an embodiment of generating a HARQ-ACK bit sequence based on a DAI signaled according to the seventh embodiment described above. First, the terminal generates a HARQ-ACK bit sequence based on a first type transmission by combining HARQ-ACKs for PDSCHs based on a first type transmission in the order of a first counter-DAI value. Also, the terminal generates a HARQ-ACK bit sequence based on a second type transmission by combining HARQ-ACKs for PDSCHs based on a second type transmission in the order of a first counter-DAI value. In this case, a "NACK" is used as a HARQ-ACK for a PDSCH for which PDCCH reception has failed. According to an embodiment, if a PDCCH for scheduling a first type-based transmission is not received at all, the HARQ-ACK bit sequence generated by the terminal is configured by excluding a HARQ-ACK bit sequence for the first type-based transmission. Similarly, if a PDCCH for scheduling a second type-based transmission is not received at all, the HARQ-ACK bit sequence generated by the terminal is configured by excluding a HARQ-ACK bit sequence for the second type-based transmission. The terminal configures an entire HARQ-ACK bit sequence by combining the HARQ-ACK bit sequence for the first type-based transmission and the HARQ-ACK bit sequence for the second type-based transmission in a preset order. According to an embodiment, the terminal configures an entire HARQ-ACK bit sequence by appending the HARQ-ACK bit sequence for the first type-based transmission next to the HARQ-ACK bit sequence for the second type-based transmission. Referring to FIG. 33, the HARQ-ACK bit sequence configured by the terminal is [x 0 (0) , x 1 (0) , x 2 (0) , x 0 (1) , x 1 (1) , x 2 (1) , x 3 (1) , x 0 (2) , x 1 (2) , x2 (2) , x 0 (3) , x 1 (3) , x 2 (3) , x 3 (3) , y 0 (0) , y 1 (0) , y 0 (1) However, the present invention is not limited to this, and the bit sequences may be combined in reverse order to form the entire HARQ-ACK bit sequence.

[0252] Meanwhile, according to the seventh embodiment, the transmission type is divided into the first type transmission and the second type transmission according to the number of CBGs included in the PDSCH, and an independent DAI value is signaled for each transmission type, thereby reducing the overhead of DCI. However, there is a drawback in that the UE must always receive PDCCHs that schedule different transmission types.

[0253] FIG. 34 is a diagram illustrating a DAI signaling method according to an eighth embodiment of the present invention. The eighth embodiment of the present invention is implemented by combining at least some of the configurations of the second embodiment and the seventh embodiment described above. That is, the base station divides the transmission type into a first type transmission and a second type transmission according to the number of CBGs included in the scheduled PDSCH, and generates a first counter-DAI (i.e., counter-DAI#1) and a first total-DAI (i.e., total-DAI#1) value based on the number of PDSCHs, 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 CBGs, independently for each transmission type. In this case, if the value of the first counter-DAI is an even number, the base station transmits 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, respectively, through the first total-DAI field and the second total-DAI field of the PDCCH. However, if the value of the first counter-DAI is odd, the base station transmits the first and second total-DAI values ​​for a type different from the transmission type of the PDSCH scheduled by the PDCCH through the first and second total-DAI fields of the PDCCH, respectively, where the definition of the DAI value is the same as that of the seventh embodiment described above.

[0254] In the embodiment of Fig. 34, the situation in which CBG(s) are transmitted through each component carrier is the same as in the seventh embodiment described above. The PDSCH scheduled to component carriers #0 and #3 is a PDSCH based on the first type transmission, and the PDSCH scheduled to component carriers #1, #4, #5, and #7 is a PDSCH based on the second type 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 in which the PDSCH based on the first type transmission is scheduled are (0, 1, 0, 1) and (1, 3, 1, 2), respectively. Also, the values ​​of the (1st Counter-DAI, 1st Total-DAI, 2nd Counter-DAI, 2nd Total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7 on which PDSCH based on the 2nd type transmission is scheduled are (0, 3, 0, 2), (1, 1, 0, 1), (2, 3, 1, 2), and (3, 1, 1, 1), respectively. Meanwhile, the method of generating a HARQ-ACK bit sequence based on the DAI signaled according to the 8th embodiment is the same as the embodiment of FIG. 33 described above.

[0255] Meanwhile, according to the above-mentioned eighth embodiment, the transmission type is divided into a first type transmission and a second type transmission according to the number of CBGs included in the PDSCH, and an independent DAI value is signaled for each transmission type, thereby reducing DCI overhead. Also, even if the terminal receives only a PDCCH that schedules a PDSCH based on one transmission type, it can know the number of PDSCHs and CBGs based on other transmission types. However, the terminal must always receive multiple PDCCHs that indicate the total-DAI for different types.

[0256] FIG. 35 is a diagram illustrating a DAI signaling method according to a ninth embodiment of the present invention. The ninth embodiment of the present invention is implemented by combining at least some of the configurations of the third embodiment and the seventh embodiment described above. That is, the base station divides the transmission type into a first type transmission and a second type transmission according to the number of CBGs included in the scheduled PDSCH, and 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 independently. 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 used for both the two transmission types. The base station transmits the first counter-DAI value and the second counter-DAI value according to the transmission type of the PDSCH through the first counter-DAI field and the second counter-DAI field of the PDCCH for scheduling the corresponding PDSCH. Furthermore, the base station transmits a common first total-DAI value and a common second total-DAI value via the first total-DAI field and the second total-DAI field of all PDCCHs regardless of the transmission type.

[0257] According to an additional embodiment, if only one PDSCH of any one transmission type is scheduled in all component carriers, a common first total-DAI value is determined to be a preset value. According to an embodiment of the present invention, if a 2-bit total-DAI is used, the preset value is a binary number "11". Also, if a 3-bit total-DAI is used, the preset value is "011" or "111". Meanwhile, a method of determining the first counter-DAI and second counter-DAI values ​​is the same as that of the above-mentioned seventh embodiment.

[0258] In the embodiment of Fig. 35, the situation in which CBG(s) are transmitted through each component carrier is the same as in the above-mentioned seventh embodiment. It is also 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 based on the second type 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 PDSCHs based on the first type transmission are scheduled are (0, 3, 0, 2) and (1, 3, 1, 2), respectively. In addition, the values ​​of the (1st counter-DAI, 1st total-DAI, 2nd counter-DAI, 2nd total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7 in which a PDSCH based on the 2nd type transmission is scheduled are (0, 3, 0, 2), (1, 3, 0, 2), (2, 3, 1, 2), and (3, 3, 1, 2), respectively.

[0259] 36 is a diagram showing an embodiment of generating a HARQ-ACK bit sequence based on the DAI signaled according to the above-mentioned ninth embodiment. The HARQ-ACK bit sequence is generated in the same manner as in the embodiment of FIG. 33. However, since the value of the (1st Total-DAI, 2nd Total-DAI) field is (3, 2) instead of (1, 1) for the PDSCH based on the first type transmission, the HARQ-ACK bit sequence includes dummy HARQ-ACK[z 0 , z 1 , z 2 ] is included in the additions.

[0260] 37 is a diagram illustrating a DAI signaling method according to a tenth embodiment of the present invention. If a base station configures CBG-based transmission, the number of CBG(s) per TB configured in each component carrier or cell is different. For example, the number of CBGs per TB in component carrier #0 is configured to be 2, and the number of CBGs per TB in component carrier #1 is configured to be 4. Also, if a terminal is configured in a transmission mode in which two TBs are transmitted from one PDSCH, the number of CBG(s) per TB is set to be the same for the two TBs.

[0261] A terminal configured in a transmission mode in which one TB is transmitted from one PDSCH should transmit HARQ-ACK bit(s) based on the number of the configured CBG(s) to the base station. If a terminal configured in a transmission mode in which two TBs are transmitted from one PDSCH is configured not to perform spatial bundling, the terminal should transmit HARQ-ACK bit(s) based on twice the number of the CBG(s) per the configured TB to the base station. On the other hand, if a terminal configured in a transmission mode in which two TBs are transmitted from one PDSCH is configured to perform spatial bundling, the terminal should transmit HARQ-ACK bit(s) based on the number of the CBG(s) per the configured TB to the base station. In the following embodiments of the present invention, it is assumed that a terminal is configured to perform spatial bundling or configured in a transmission mode in which one TB is transmitted from one PDSCH. A specific embodiment of a HARQ-ACK bundling method including spatial bundling will be described later. However, the embodiment of the present invention may be extended and applied to a terminal configured in a transmission mode in which two TBs are transmitted from one PDSCH and configured not to perform spatial bundling. According to the embodiment of the present invention, the DCI of the PDCCH for scheduling the PDSCH includes a counter-DAI and a total-DAI. In this case, the counter-DAI indicates 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 indicates the total number of CBG groups scheduled in all component carriers. Here, a CBG group is a group in which S CBGs are bundled together. According to one embodiment, in the counter-DAI and the total-DAI, the TB-based PDSCH is treated the same as a CBG-based transmission consisting of S CBGs. That is, it is assumed that the TB-based PDSCH includes one CBG group. Therefore, even if the terminal receives the TB-based PDSCH, it should feed back an S-bit HARQ-ACK.The S-bit HARQ-ACK is generated by repeating a 1-bit TB-based HARQ-ACK or by mapping a NACK to the remaining bits. For example, if the total-DAI value is 3, the UE determines that a total of 3*S CBGs have been transmitted over all component carriers. Therefore, the UE should transmit a total of 3*S-bit HARQ-ACK. If two TBs are transmitted from one PDSCH and spatial bundling is not performed, the UE should transmit a total of 2*3*S-bit HARQ-ACK.

[0262] Table 13 shows the number of CBG(s) that each DAI value indicates when the Total-DAI and Counter-DAI fields consist of two bits. Table 14 shows the number of CBG(s) that each DAI value indicates when the Total-DAI and Counter-DAI fields consist of three bits.

[0263] [Table 13]

[0264] [Table 14]

[0265] In Tables 13 and 14, the subscript c indicates the index of the component carrier (or cell). DL C=DAI , c is the counter-DAI value of component carrier C, and V DL T-DAIis the Total-DAI value. According to the signaling methods of Tables 13 and 14, if the Total-DAI or Counter-DAI value is A, the number of CBGs indicated by the corresponding DAI field is S*(2^B+A), where B is the bit width of the Counter-DAI or Total-DAI. According to an embodiment of the present invention, the number S of CBGs included in one CBG group is represented by the granularity of the number of CBGs represented by the Counter-DAI or Total-DAI.

[0266] According to an embodiment of the present invention, the value of the number S of CBGs included in one CBG group is determined in various ways. According to one embodiment, the value of S is fixed to S=2. Preferably, S is composed of UE-specific RRC signals. According to another embodiment, S is determined to be the greatest common divisor of the number of CBGs configured in each component carrier. For example, if two CBGs are configured in component carrier #0 and six CBGs are configured in component carrier #1, S is set to 2. Also, if four CBGs are configured in component carrier #0 and eight CBGs are configured in component carrier #1, S is set to 4.

[0267] According to another embodiment, in the transmission mode in which one TB is transmitted from one component carrier, the value of S is fixed to S=2, and in the transmission mode in which two TBs are transmitted from one component carrier, the value of S is fixed to S=4. According to yet another embodiment, in the transmission mode in which all component carriers are configured in the transmission mode in which only one TB is transmitted, S is determined to be the greatest common divisor of the number of CBGs configured in each component carrier. Also, in the transmission mode in which only one TB is transmitted from one component carrier, S is determined to be twice the greatest common divisor of the number of CBGs configured in each component carrier. For example, in the transmission mode in which two TBs are transmitted from one component carrier, if two CBGs are configured in component carrier #0 and six CBGs are configured in component carrier #1, S is set to 4. Also, if four CBGs are configured in component carrier #0 and eight CBGs are configured in component carrier #1, S is set to 8.

[0268] The bit width of the Counter-DAI field and the Total-DAI field expected by the terminal may vary depending on the number S of CBGs included in one CBG group. According to an embodiment, the bit width of the Counter-DAI field and the Total-DAI field is 2+ceil(log 2 (X / S)), where X is the largest number among the numbers of CBGs of each component carrier configured in the terminal. Here, ceil(a) indicates the smallest integer number that is greater than or equal to a. For example, if two component carriers are configured in the terminal, 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 width of the Counter-DAI field and the Total-DAI field are respectively 2+ceil(log 2(4 / 2))=3 bits. If two component carriers are configured in the terminal, 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 width of the Counter-DAI field and the Total-DAI field are respectively set to 2+ceil(log 2 (8 / 4) = 3 bits.

[0269] Referring to FIG. 37, PDSCH is transmitted to the terminal via component carriers #0, #1, #3, #4, #5, and #7. In this case, the number of CBGs transmitted via component carriers #0, #1, #3, #4, #5, and #7 is 2, 4, 6, 8, 2, and 4, respectively. According to one embodiment of the present invention, the number S of CBGs included in one CBG group is set to 2, which is the greatest common divisor of the number of CBGs. Therefore, the values ​​of the (Counter-DAI, Total-DAI) fields of each PDCCH for component carriers #0, #1, #3, #4, #5, and #7 are (0, 13), (1, 13), (3, 13), (6, 13), (10, 13), and (11, 13), respectively.

[0270] 38 is a diagram illustrating a method of compressing a HARQ-ACK according to an embodiment of the present invention. If the length of a HARQ-ACK payload to be transmitted by a terminal configured for CBG-based transmission exceeds the maximum transmission capacity of a PUCCH, the HARQ-ACK payload should be compressed according to the maximum transmission capacity of a PUCCH.

[0271] According to an embodiment of the present invention, the UE transmits TB-based HARQ-ACK for some TBs (or PDSCHs) among all TBs, and transmits CBG-based HARQ-ACK for the remaining TBs (or PDSCHs). Referring to FIG. 38, the HARQ-ACK payload of the UE is configured into three parts as follows. First, the "header" part indicates how to interpret the following HARQ-ACK payload. More specifically, the "header" indicates the index of the TB (or PDSCH) on which the CBG-based HARQ-ACK is transmitted. The "header" also indicates the index of the TB (or PDSCH) on which the TB-based HARQ-ACK is transmitted. Next, the "TB-A / N" field includes the TB-based HARQ-ACK for the TB (or PDSCH) instructed by the "header" to transmit the TB-based HARQ-ACK. In this case, the order of the TB-based HARQ-ACK is 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) instructed to transmit the CBG-based HARQ-ACK from the "Header". In this case, the order of the CBG-based HARQ-ACK is set in ascending order of the counter DAI value of the TB (or PDSCH). Incidentally, if the number of bits of the CBG-based HARQ-ACK for different TBs is different, NACK is attached so that the length of the CBG-based HARQ-ACK payload for all TBs is the same as the length of the longest CBG-based HARQ-ACK among the CBG-based HARQ-ACKs.

[0272] The 'header' section is set as follows: When HARQ-ACKs for a total of X TBs are transmitted, the terminal transmits CBG-based HARQ-ACKs for C TB(s) out of X, and transmits TB-based HARQ-ACKs for the remaining Xc TB(s). Here, a method for the terminal and base station to determine the value of c will be described later. The 'header' section indicates information for selecting c out of X TB(s). The 'header' section is made up of a bitmap of X-bit length. Each bit indicates information on whether a TB-based HARQ-ACK or a CBG-based HARQ-ACK is transmitted for each TB. As another embodiment, the number of cases in which c out of X TB(s) are selected is

number

number

number

number

[0273] According to an embodiment of the present invention, the terminal and the base station determine the value of c in the following manner. The base station and the terminal can know the maximum number of transmission bits that the PUCCH carrying the HARQ-ACK can transmit. The number of the maximum transmission bits is assumed to be B. Also, the length of the CBG-based HARQ-ACK payload is assumed to be N. The terminal and the base station identify how many TBs (or PDSCHs) are scheduled in the entire component carriers through the Total-DAI value. The total number of scheduled TBs (or PDSCHs) is assumed to be X. In this case, c is determined to be the largest integer that satisfies the following Mathematical Formula 1.

[0274]

number

[0275] In Equation 1, the values ​​of X, N, and B are known to the UE and the BS, so that the UE and the BS can identify the value of c without error. In addition, once the value of c is determined, the length of the HARQ-ACK payload transmitted by the UE is

number

[0276] For example, if X=9, B=22, and N=4, c=2 is obtained by Equation 1. Therefore, when the terminal generates the HARQ-ACK, it configures an N-bit CBG-based HARQ-ACK for two TBs (or PDSCHs) out of a total of nine TBs (or PDSCHs), and configures a 1-bit TB-based HARQ-ACK for the remaining seven TBs (or PDSCHs). In this case, the base station always expects a 21-bit HARQ-ACK. If the 2-bit HARQ-ACK received by the base station is [001111101100011101010], the interpretation of the HARQ-ACK is as follows. In the HARQ-ACK, the "header"

number

[0277] 39 to 40 are diagrams illustrating a method of performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. A diagram illustrating a method of performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. In one PDSCH, a transmission mode is configured in which two TBs are transmitted, and if a terminal configured for CBG-based transmission performs spatial bundling, the CBG-based HARQ-ACK for each TB should be bundled. In addition, the terminal is configured to perform spatial bundling of CBG-based HARQ-ACKs transmitted through different slots. A method of performing spatial bundling according to an embodiment of the present invention is as follows. Incidentally, a method of performing spatial bundling will be described, which is used when bundling HARQ-ACKs between two different TBs.

[0278] If the same number N of maximum CBGs is configured for each TB, let the number of CBGs included in TB#1 be M1 and the number of CBGs included in TB#2 be M2, and assume that 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 contains more CBGs than TB#1, switch the indexes of TB#1 and TB#2 and apply the embodiments of the present invention. If the terminal is configured not to perform bundling, the terminal should transmit a total of 2*N-bit HARQ-ACK, N bits per TB. At this time, if M1 < N, it is expressed that the corresponding TB contains M1 CBG(s) and N - M1 virtual CBG(s). The N-bit HARQ-ACK for TB#1 is [a 1 、a 2 、…、a M1 、x、…、x], and the N-bit HARQ-ACK for TB#2 is assumed to be [b 1 、b 2 、…、b M2 、x、…、x]. Here, x is a value obtained by stuffing HARQ-ACK for virtual CBG(s) in order to match the length of the HARQ-ACK payload, and is later mapped to NACK.

[0279] First, FIG. 39 shows a first embodiment of performing spatial bundling of HARQ-ACK. More specifically, FIGS. 39(a) to 39(c) show respective embodiments of performing spatial bundling of HARQ-ACK when M1 = N and M2 = 1 to 3. If M = N, the indexes of the CBGs to be bundled among the CBGs included in the two TBs are selected so that the resource elements assigned to the two TBs overlap as much as possible in the time-frequency domain. This is because a higher correlation degree can be expected if they overlap as much as possible in the time-frequency domain. More specifically, if M1 = N, the indexes of the CBGs to be bundled among the CBGs included in the two TBs follow the values in Table 15 according to the M1 value and the M2 value.

[0280]

Table 15

[0281] Referring to Table 15, if M1=4 and M2=2, the values ​​of {1, 4} are obtained as the index of the CBG to be bundled. Therefore, referring to FIG. 39(b), the first CBG of TB#2 is bundled with the first CBG of TB#1, and the second CBG of TB#2 is bundled with the fourth CBG of TB#1. Also, if M1=4 and M2=3, the values ​​of {1, 2, 4} are obtained as the index of the CBG to be bundled. Therefore, referring to FIG. 39(c), the first CBG of TB#2 is bundled with the first CBG of TB#1, the second CBG of TB#2 is bundled with the second CBG of TB#1, and the third CBG of TB#2 is bundled with the fourth CBG of TB#1.

[0282] Table 16 illustrates another method of performing spatial bundling according to the first embodiment described above. If M1=N, the index of the CBG to be bundled among the CBGs included in the two TBs follows the values ​​in Table 16 according to the values ​​of M1 and M2.

[0283] [Table 16]

[0284] Referring to Table 16, if M1=4 and M2=3, the values ​​{1, 3, 4} are obtained as the indices of the CBGs to be bundled. Thus, the first CBG of TB#2 is bundled with the first CBG of TB#1, the second CBG of TB#2 is bundled with the third CBG of TB#1, and the third CBG of TB#2 is bundled with the fourth CBG of TB#1.

[0285] Next, FIG. 40 shows a second embodiment in which spatial bundling of HARQ-ACK is performed. More specifically, FIGS. 40(a) to 40(f) show respective embodiments of performing spatial bundling of HARQ-ACK when M1 < N. If M1 < N, some of the HARQ-ACK bit(s) of TB#2 are preferentially mapped to the HARQ-ACK bit(s) not used in TB#1 (or used for virtual CBG), and bundling is performed between the remaining HARQ-ACK bit(s) of TB#2 and the HARQ-ACK bit(s) of TB#1. First, FIGS. 40(a) to 40(c) show embodiments when M1 < N and M1 + M2 is less than or equal to N. In this case, the N-bit HARQ-ACK for which spatial bundling is performed consists of the M1-bit HARQ-ACK of TB#1, the M2-bit HARQ-ACK of TB#2, and the N-(M1 + M2)-bit NACK. Also, FIGS. 40(d) to 40(f) show embodiments when M1 < N and M1 + M2 is greater than N and less than 2*N. In this case, M1 + M2 - N bit(s) of the N-bit HARQ-ACK for which spatial bundling is performed are configured by performing bundling (i.e., binary AND operation) between M1 + M2 - N bit(s) of the HARQ-ACK of TB#1 and M1 + M2 - N bit(s) of the HARQ-ACK of TB#2. Also, 2*N-(M1 + M2) bit(s) of the N-bit HARQ-ACK for which spatial bundling is performed consist of the remaining N - M2 bit(s) of the HARQ-ACK of TB#1 and the remaining N - M1 bit(s) of the HARQ-ACK of TB#2.

[0286] As a more specific example, [b 1 、b 2 、…、b M2 is divided into [b 1 、b 2 、…、b M2-k and [b M2-k+1 、b M2-k+2 、…、b M2 . Here, k = k = N - M1. And [b 1 、b 2 、…、b M2-k and [a1 , a 2 , …, a M2-k ] is subjected to a binary AND operation. The result obtained in this way is then 1 , c 2 , …, c M2-k Finally, the bundled HARQ-ACK is 1 , c 2 , …, c M2-k ], [a M2-k+1 , a M2-k+1 , …, a M1 ], [b M2-k+1 , b M2-k+2 , …, b M2 ] in sequence. According to an embodiment of the present invention, the order of concatenation of HARQ-ACKs can be switched. If the length of the concatenated HARQ-ACK is less than N-bits, x is added to the end of the HARQ-ACK to match it to N-bits. In this case, x is mapped to a NACK. Finally, the bundled HARQ-ACK is converted into [o 1 ,o 2 , …, o N ], then the number of bits of HARQ-ACK depending on the value of index i is O i is obtained as shown in mathematical formula 2.

[0287]

number

[0288] Here, & means binary AND operation. Also, k=N-M1, and α=max{N-(M1+M2), 0}. In this case, max{s, t} returns the larger of s and t. Here, x is mapped to NACK.

[0289] In another embodiment of the present invention, the HARQ-ACK that has been finally bundled is 1 ,o 2 , …, o N ], then the number of bits of HARQ-ACK depending on the value of index i is O i is obtained as shown in mathematical formula 3.

[0290]

number

[0291] where λ is M1+M2-N, and x is mapped to a NACK.

[0292] Referring to Equation 2, Equation 3, and FIG. 40, the HARQ-ACK finally bundled by the HARQ-ACK for two TBs is as follows. Referring to FIG. 40(a), when the HARQ-ACK for two TBs is [a 1 , x, x, x] and [b 1 , x, x, x], the final bundling HARQ-ACK is [a 1 , b 1 , x, x]. Referring to FIG. 40(b), the HARQ-ACK for the two TBs is [a 1 , a 2 , x, x] and [b 1 , x, x, x], the final bundling HARQ-ACK is [a 1 , a 2 , b 1 , x]. With reference to FIG. 40(c), the HARQ-ACK for the two TBs is [a 1 , a 2 , x, x] and [b 1 , b 2 , x, x], the final bundling HARQ-ACK is [a 1 , a 2 , b 1 , b 2 ]. With reference to FIG. 40(d), the HARQ-ACK for two TBs is [a 1 , a 2 , a 3 , x] and [b 1 , x, x, x], the final bundling HARQ-ACK is [a 1 , a 2 , a 3 , b 1 ]. With reference to FIG. 40(e), the HARQ-ACK for two TBs is [a1 , a 2 , a 3 , x] and [b 1 , b 2 , x, x], the final bundling HARQ-ACK is [a 1 &b 1 , a 2 , a 3 , b 2 ], where & is a binary AND operation. With reference to FIG. 40(f), the HARQ-ACK for two TBs is [a 1 , a 2 , a 3 , x] and [b 1 , b 2 , b 3 , x], the final bundling HARQ-ACK is [a 1 &b 1 , a 2 &b 2 , a 3 , b 3 ]. Also, the HARQ-ACK for two TBs is [a 1 , a 2 , a 3 , a 4 ] and [b 1 , b 2 , b 3 , x], the final bundling HARQ-ACK is [a 1 &b 1 , a 2 &b 2 , a 3 &b 3 , a 4 ].

[0293] 41 and 42 are diagrams illustrating in more detail a method of spatial bundling HARQ-ACK according to an embodiment of the present invention. In FIG. 41 and FIG. 42, N is the maximum number of CBGs per TB consisting of RRC signals, M1 is the number of CBGs included in TB#1, and M2 is the number of CBGs included in TB#2. Also, 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 iwhere & denotes a binary AND operation, and x is mapped to a NACK.

[0294] According to an embodiment of the present invention, a DCI for a terminal configured in a transmission mode in which two TBs are transmitted from one PDSCH and configured for CBG-based transmission is set as follows. First, it is assumed that N CBGs are configured for one TB. If the terminal is configured not to perform spatial bundling, an N-bit CBGTI (CBG transmission information) field exists for each TB in the DCI of the terminal to indicate which CBG is transmitted for each TB. Also, an MCS (modulation and coding scheme), an RV (redundancy version), and an NDI (new data indicator) exist for each TB. If the CBGTI for one TB is all 0, it is indicated that the corresponding TB is not transmitted. Also, if the CBGTI for one TB is all 0 and the MCS and RV values ​​are specific values, it is indicated that the corresponding TB is not transmitted. Here, the specific value of MCS is 0 and the specific value of RV is 1.

[0295] According to another embodiment of the present invention, if there is at least one virtual CBG between two TBs to be bundled, bundling is performed as follows. First, NACK is mapped to HARQ-ACK "x" for the virtual CBG. Also, Q=min(M1, M2) is defined. Incidentally, if TB#1 is TB-based transmission, M1=1 is assumed, and if TB#2 is TB-based transmission, M2=1 is assumed. ACK is 1 and NACK is 0. When generating a bundled HARQ-ACK from the HARQ-ACKs for two TBs, a binary AND operation is performed on the 1st to Qth HARQ-ACK bits, and a binary OR operation is performed on the Q+1th to Nth HARQ-ACK bits. If TB#1 contains four CBGs (i.e., M1=4) and the number of CBGs is four (i.e., N=4), and TB#2 contains two CBGs (i.e., M2=2) and the number of CBGs is four (i.e., N=4), the HARQ-ACK for TB#1 is [a 1 , a 2 , a 3 , a 4 ], and the HARQ-ACK for TB#2 is [b 1 , b 2 , 0, 0]. And Q=2. Therefore, the first two bits are binary ANDed, and the last two (i.e., NQ) bits are binary ORed. Thus, the bundled HARQ-ACK is [a 1 &b 1 , a 2 &b 2 , a 3 |0, a 4 |0], where & is a binary AND operation and | is a binary OR operation. Incidentally, such bundling methods are also used in spatial bundling, or only in bundling between other TBs other than spatial bundling.

[0296] According to another embodiment of the present invention, if there is at least one virtual CBG in two TBs to be bundled, bundling is performed as follows. First, the HARQ-ACK for the virtual CBG is denoted as "x", and a NACK is mapped to "x" after bundling. When generating a bundled HARQ-ACK with the HARQ-ACKs for two TBs, a ternary AND operation is performed on the two HARQ-ACKs. At this time, a truth table of the ternary AND operation is shown in Table 17. After bundling, x is mapped to a NACK. If TB#1 includes four CBGs (i.e., M1=4) and the number of CBGs configured is four (i.e., N=4), and TB#2 includes two CBGs (i.e., M2=2) and the number of CBGs configured is four (i.e., N=4), the HARQ-ACK for TB#1 is [a 1 , a 2 , a 3 , a 4 ], and the HARQ-ACK for TB#2 is [b 1 , b 2 , x, x]. Therefore, the bundled HARQ-ACK is [a 1 ￥b 1 , a 2 ￥b 2 , a 3 ￥x、a 4 \x], where the operator \ is shown in Table 17. Incidentally, such bundling methods are also used in spatial bundling, or only in other inter-TB bundling except spatial bundling.

[0297] [Table 17]

[0298] On one hand, if the terminal is configured to perform spatial bundling, there is one N-bit CBGTI field in the DCI of the terminal. Also, there are MCS, RV, and NDI per TB. The process of determining which CBG the terminal has received is as follows. The terminal identifies whether the corresponding TB has been transmitted through the MCS and RV values of each TB. Here, if the MCS and RV are specific values, it indicates that the corresponding TB has not been transmitted. For example, the specific value of MCS is 0 and the specific value of RV is 1. If there is one transmitted TB, the terminal interprets that the N-bit CBGTI indicates which CBG of that TB has been transmitted. That is, if the nth bit of the N-bit CBGTI is 1 (assuming here that 1 indicates being transmitted), the terminal identifies that the nth CBG has been transmitted. If there are two transmitted TBs, the terminal identifies them in the same way as the method by which the N-bit CBGTI indicates which CBG of those TBs has been transmitted. For example, if the ith HARQ-ACK bit for which spatial bundling has been performed is calculated by performing a binary AND operation on the HARQ-ACK bit for the kth CBG of TB#1 and the HARQ-ACK bit for the jth CBG of TB#2, if the ith bit of the N-bit CBGTI in the DCI is 1, it indicates that the kth CBG of TB#1 has been transmitted and the jth CBG of TB#2 has been transmitted. As an example of the present invention, assuming that spatial bundling is performed in the manner of Mathematical Formula 4 where M1 < N, if the ith bit of the N-bit CBGTI [d 1 、d 2 、…、d N is 1, it identifies that the following CBG has been transmitted.

[0299]

Number

[0300] Here, CBG (1) i indicates the ith CBG of TB#1, and CBG (2) iindicates the i-th CBG of TB#2. M1 and M2 are the numbers of CBGs scheduled in TB#1 and TB#2, respectively, and are identified from the MCS value of each TB of the DCI.

[0301] FIG. 43 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention. In an embodiment of the present invention, the terminal is embodied as various types of wireless communication devices or computing devices that guarantee portability and mobility. The terminal is referred to as UE (User Equipment), STA (Station), MS (Mobile Subscriber), etc. In addition, in an embodiment of the present invention, the base station controls and manages cells (e.g., macrocells, femtocells, picocells, etc.) corresponding to a service area, and performs functions such as signal transmission, channel assignment, channel monitoring, self-diagnosis, and relaying. The base station is referred to as gNB (next generation NodeB) or AP (Access Point), etc.

[0302] As shown, a terminal 100 according to an embodiment of the present invention includes a processor 110 , a communication unit 120 , a memory 130 , a user interface unit 140 , and a display unit 150 .

[0303] First, the processor 110 executes various commands or programs to process data within the terminal 100. The processor 100 also controls the overall operation of the terminal 100 including each unit, and controls the transmission and reception of data between the units. Here, the processor 110 is configured to perform operations according to the embodiments described in the present invention. For example, the processor 110 may receive slot configuration information, determine the slot configuration based thereon, and perform communication according to the determined slot configuration.

[0304] Next, the communication module 120 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN connection using a wireless LAN. For this purpose, the communication module 120 includes a plurality of network interface cards (NICs) such as cellular communication interface cards 121, 121 and an unlicensed band communication interface card 123, either built-in or external. In the drawings, the communication module 120 is illustrated as an integrated module, but the respective network interface cards may be arranged independently depending on the circuit configuration or application, unlike the drawings.

[0305] The cellular communication interface card 121 transmits and receives wireless signals to and from at least one of the base station 200, an external device, and a server via a mobile communication network, and provides a cellular communication service in a first frequency band based on instructions from the processor 110. According to an embodiment, the cellular communication interface card 121 includes at least one NIC module that utilizes a frequency band below 6 GHz. The at least one NIC module of the cellular communication interface card 121 independently performs cellular communication with at least one of the base station 200, an external device, and a server according to a cellular communication standard or protocol of the frequency band below 6 GHz supported by the corresponding NIC module.

[0306] The cellular communication interface card 122 transmits and receives wireless signals to and from at least one of the base station 200, an external device, and a server via a mobile communication network, and provides a cellular communication service in the second frequency band based on instructions from the processor 110. According to an embodiment, the cellular communication interface card 122 includes at least one NIC module that utilizes a frequency band of 6 GHz or higher. The at least one NIC module of the cellular communication interface card 122 independently performs cellular communication with at least one of the base station 200, an external device, and a server according to a cellular communication standard or protocol of the 6 GHz or higher frequency band supported by the corresponding NIC module.

[0307] The unlicensed band communication interface card 123 transmits and receives wireless signals to and from at least one of the base station 200, the external device, and the server through the third frequency band, which is an unlicensed band, and provides communication services of the unlicensed band based on instructions from the processor 110. The unlicensed band communication interface card 123 includes at least one NIC module that uses the unlicensed band. For example, the unlicensed band may be a 2.4 GHz or 5 GHz band. The at least one NIC module of the unlicensed band communication interface card 123 performs cellular communication with at least one of the base station 200, the external device, and the server, independently or dependently, according to the unlicensed band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0308] Next, the memory 130 stores a control program and various data associated therewith used by the terminal 100. Such a control program includes a predetermined program required for the terminal 100 to perform wireless communication with at least one of the base station 200, an external device, and a server.

[0309] Next, the user interface 140 includes various types of input / output means provided in the terminal 100. That is, the user interface unit 140 receives user input using various input means, and the processor 110 controls the terminal 100 based on the received user input. Also, the user interface 140 performs output based on a command from the processor 110 using various output means.

[0310] Then, the display unit 150 outputs various images on a display screen. The display unit 150 outputs various display objects, such as a user interface, based on the contents performed by the processor 110 or a control command of the processor 110.

[0311] The base station 200 according to the embodiment of the present invention also includes a processor 210 , a communication module 220 , and a memory 230 .

[0312] First, the processor 210 executes various commands or programs to process data within the base station 200. The processor 210 also controls the overall operation of the base station 200 including each unit, and controls transmission and reception of data between the units. Here, the processor 210 is configured to perform operations according to the embodiments described in the present invention. For example, the processor 210 may signal slot configuration information and perform communication according to the signaled slot configuration.

[0313] Next, the communication module 220 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN connection using a wireless LAN. For this purpose, the communication module 120 includes a plurality of network interface cards, such as cellular communication interface cards 221 and 222 and an unlicensed band communication interface card 223, either built-in or external. In the drawings, the communication module 220 is illustrated as an integrated module, but the respective network interface cards may be arranged independently depending on the circuit configuration or application, unlike the drawings.

[0314] The cellular communication interface card 221 transmits and receives wireless signals to and from at least one of the terminal 100, the external device, and the server via a mobile communication network, and provides a cellular communication service in a first frequency band based on an instruction from the processor 210. According to an embodiment, the cellular communication interface card 221 includes at least one NIC module that uses a frequency band below 6 GHz. The at least one NIC module of the cellular communication interface card 221 independently performs cellular communication with at least one of the terminal 100, the external device, and the server according to a cellular communication standard or protocol of a frequency band below 6 GHz supported by the corresponding NIC module.

[0315] The cellular communication interface card 222 transmits and receives wireless signals to and from at least one of the terminal 100, an external device, and a server via a mobile communication network, and provides a cellular communication service in the second frequency band based on instructions from the processor 210. According to an embodiment, the cellular communication interface card 222 includes at least one NIC module that utilizes several frequency bands above 6 GHz. At least one NIC module of the cellular communication interface card 222 independently performs cellular communication with at least one of the terminal 100, an external device, and a server according to a cellular communication standard or protocol of the frequency band above 6 GHz supported by the corresponding NIC module.

[0316] The unlicensed band communication interface card 223 transmits and receives wireless signals to and from at least one of the terminal 100, an external device, and a server via the third frequency band, which is an unlicensed band, and provides communication services of the unlicensed band based on instructions from the processor 210. The unlicensed band communication interface card 223 includes at least one NIC module that uses the unlicensed band. For example, the unlicensed band may be a 2.4 GHz or 5 GHz band. The at least one NIC module of the unlicensed band communication interface card 223 performs cellular communication with at least one of the terminal 100, an external device, and a server, independently or dependently, according to an unlicensed band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0317] The terminal 100 and base station 200 shown in FIG. 43 are block diagrams according to an embodiment of the present invention, and the separated blocks are illustrated by logically distinguishing the elements of the devices. Thus, the above-mentioned device elements may be mounted on one chip or multiple chips depending on the design of the device. Also, some components of the terminal 100, such as the user interface unit 150, may be selectively provided in the terminal 100. Also, the user interface 140 and the display unit 150 may be additionally provided in the base station 200 as necessary.

[0318] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and are not limiting. For example, each component described as a single form may be implemented in a distributed form, and each component described as a distributed form may be implemented in a combined form.

[0319] The scope of the present invention is indicated by the claims set forth below rather than by the above detailed description, and all modifications and variations derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0320] 110 Processor 121 Cellular communication interface card (first frequency band) 122 Cellular communication interface card (second frequency band) 123 Unlicensed spectrum communications interface card (third frequency band) 130 Memory 140 User Interface 150 display units 210 Processor 221 Cellular communication interface card (first frequency band) 222 Cellular communication interface card (second frequency band) 223 Unlicensed spectrum communications interface card (third frequency band) 230 Memory

Claims

1. A user terminal of a wireless communication system, comprising: A communication module; a processor configured to control the communication module; The processor, configured to receive a plurality of downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH); Each DCI of the plurality of DCIs corresponds to: i) a first format including a counter-downlink allocation index (DAI) or a second format including the counter-DAI and a total-DAI; ii) schedules either a transport block (TB)-based PDSCH reception or a code block group (CBG)-based PDSCH reception for a corresponding cell among a plurality of cells; The processor, performing the CBG-based PDSCH reception and the TB-based PDSCH reception based on the plurality of DCIs; and generating a hybrid automatic repeat request acknowledgment (HARQ-ACK) codebook including a first HARQ-ACK bit sequence for receiving the TB-based PDSCH and a second HARQ-ACK bit sequence for receiving the CBG-based PDSCH for the plurality of cells; The plurality of cells includes at least one CBG cell configured for CBG-based PDSCH transmission, A user terminal, in which in the at least one CBG cell, the TB-based PDSCH reception or the CBG-based PDSCH reception is performed based on the first format or the second format of a corresponding DCI among the multiple DCIs.

2. The user terminal of claim 1, wherein at least one of the counter-DAI and the total-DAI included in each DCI of the plurality of DCIs is applied separately to each of the first HARQ-ACK bit sequence for the TB-based PDSCH reception or the second HARQ-ACK bit sequence for the CBG-based PDSCH reception.

3. The processor further comprises: configured to transmit HARQ-ACK information including the HARQ-ACK codebook; The user terminal of claim 1 , wherein the HARQ-ACK codebook is generated by appending the second HARQ-ACK bit sequence to the first HARQ-ACK bit sequence.

4. The plurality of cells further includes at least one TB cell configured for TB-based PDSCH transmission; The user equipment of claim 1 , wherein only the TB-based PDSCH reception is performed in the at least one TB cell.

5. The processor further comprises: configured to receive configuration information for configuring a transmission method within the plurality of cells; The user equipment of claim 1, wherein each cell of the plurality of cells is configured for the CBG-based PDSCH transmission or the TB-based PDSCH transmission based on the configuration information.

6. The user terminal of claim 1 , wherein each bit of the first HARQ-ACK bit sequence is generated for each transmission block.

7. the second HARQ-ACK bit sequence for receiving the CBG-based PDSCH includes N HARQ-ACK bits for each transport block; The user terminal of claim 1 , wherein N is determined based on the number of CBGs configured for the user terminal.

8. The counter-DAI is used to identify the cumulative number of scheduled PDSCHs; The user terminal of claim 1 , wherein the Total-DAI is used to identify a total number of scheduled PDSCHs.

9. A wireless communication method in a wireless communication system, comprising: receiving a plurality of downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH), each DCI of the plurality of DCIs corresponds to i) a first format including a counter-downlink allocation index (DAI) or a second format including the counter-DAI and a total-DAI; and ii) scheduling either a transport block (TB)-based PDSCH reception or a code block group (CBG)-based PDSCH reception for a corresponding cell of a plurality of cells; performing the CBG-based PDSCH reception and the TB-based PDSCH reception based on the plurality of DCIs; generating a hybrid automatic repeat request acknowledgment (HARQ-ACK) codebook including a first HARQ-ACK bit sequence for receiving the TB-based PDSCH and a second HARQ-ACK bit sequence for receiving the CBG-based PDSCH for the plurality of cells, The plurality of cells includes at least one CBG cell configured for CBG-based PDSCH transmission, In the at least one CBG cell, the TB-based PDSCH reception or the CBG-based PDSCH reception is performed based on the first format or the second format of a corresponding DCI among the plurality of DCIs.

10. The method of claim 9, wherein at least one of the counter-DAI and the total-DAI included in each DCI of the plurality of DCIs is applied separately to each of the first HARQ-ACK bit sequence for the TB-based PDSCH reception or the second HARQ-ACK bit sequence for the CBG-based PDSCH reception.

11. transmitting HARQ-ACK information including the HARQ-ACK codebook, The method of claim 9 , further comprising: generating the HARQ-ACK codebook by appending the second HARQ-ACK bit sequence to the first HARQ-ACK bit sequence.

12. The plurality of cells further includes at least one TB cell configured for TB-based PDSCH transmission; The method of claim 9, wherein only the TB-based PDSCH reception is performed in the at least one TB cell.

13. receiving configuration information for configuring a transmission method within the plurality of cells, The method of claim 9, further comprising: configuring each cell of the plurality of cells for the CBG-based PDSCH transmission or the TB-based PDSCH transmission based on the configuration information.

14. The method of claim 9 , wherein each bit of the first HARQ-ACK bit sequence is generated for each transmission block.

15. the second HARQ-ACK bit sequence for receiving the CBG-based PDSCH includes N HARQ-ACK bits for each transport block; The method of claim 9 , wherein N is determined based on a number of CBGs configured for a user terminal.

16. The counter-DAI is used to identify the cumulative number of scheduled PDSCHs; The method of claim 9, wherein the Total-DAI is used to identify a total number of scheduled PDSCHs.

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