Terminal and wireless communication method

Abstract

A terminal for a wireless communication system and a wireless communication method using the same are disclosed. [Solution] More specifically, a terminal is disclosed that includes a communication module and a processor, the processor receiving DCI via a PDCCH that indicates PDSCH scheduling information for each cell in one or more cells(a), identifying the transmission method in each cell based on the DCI format of the DCI, receiving the PDSCH of each cell in one or more cells(a) based on the scheduling information of the PDCCH, generating a HARQ-ACK bit sequence for one or more cells(a) in response to the reception of the PDSCH of each cell(a) based on the identified transmission method of each cell, and transmitting the generated HARQ-ACK bit sequence, and a wireless communication method using the same.

Description

[Technical Field]

[0001] This invention relates to a wireless communication system. More specifically, this invention relates to a wireless communication method, apparatus, and system for transmitting and receiving data channels 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 also referred to as beyond 4G networks, post-LTE systems, or NR (new radio) systems. To achieve high data transmission rates, 5G communication systems include systems operating using ultra-high frequency (mmWave) bands above 6 GHz, and also include systems operating using frequency bands below 6 GHz to ensure coverage, with implementation at base stations and terminals being considered.

[0003] The 3GPP® (registered trademark, hereinafter the same) (3rd generation partnership project) NR system improves the efficiency of the network spectrum, enabling telecommunications carriers to provide more data and voice services with the given bandwidth. Therefore, the 3GPP NR system is designed to satisfy the demands for high-speed data and media transmission, in addition to supporting high-capacity voice. The advantages of the NR system include high processing power, low latency, support for FDD (frequency division duplex) and TDD (time division duplex) on the same platform, an improved end-user environment, and low operating costs with a simple architecture.

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

[0005] To mitigate path loss in the ultra-high frequency band and increase the transmission distance of radio waves, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, hybrid beamforming (combining analog and digital beamforming), and large-scale antenna technologies are being discussed for 5G communication systems. Furthermore, in order to improve the system network, 5G communication systems are undergoing technological development related to advanced small cells, improved small cells, cloud radio access networks (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, CoMP (coordinated multi-points), and interference cancellation.In addition, 5G systems have seen the development of advanced coding modulation (ACM) methods such as FQAM (hybrid FSK and QAM modulation) and SWSC (sliding window superposition coding), as well as advanced access technologies such as FBMC (filter bank multi-carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access).

[0006] Meanwhile, the internet, a human-centered interconnected network where humans generate and consume information, is evolving into the Internet of Things (IoT) network, where distributed components such as objects exchange and process information. Internet of Everything (IoE) technology, which combines IoT technology with big data processing technologies via connections to cloud servers and other systems, is also emerging. To realize IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, technologies such as sensor networks for connecting objects, machine-to-machine (M2M), and machine-type communication (MTC) are being researched. In an IoT environment, intelligent IT services are provided that collect and analyze data generated from connected objects to create new value in human life. IoT, through the integration and combination of traditional IT (information technology) technologies and various industries, is being 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.

[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 communication, and MTC are being realized through 5G communication technologies such as beamforming, MIMO, and array antennas. As mentioned above, the application of cloud radio access networks (cloud RAN) as a big data processing technology can also be considered an example of the fusion of 5G technology and IoT technology. In general, mobile communication systems are developed to provide voice services while ensuring user activity.

[0008] However, mobile communication systems have gradually expanded their scope beyond voice to include data services, and have now developed to the point where they can provide high-speed data services. However, due to resource shortages and user demand for high-speed services, there is a need for more advanced mobile communication systems in use today. [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 [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0012] The present invention aims 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] Furthermore, the present invention aims to provide a method for efficient retransmission when a terminal is configured to enable CBG-based transmission.

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

[0015] To solve the aforementioned problems, the following wireless communication system terminal and wireless communication method are provided.

[0016] First, according to an embodiment of the present invention, a terminal of a wireless communication system includes a communication module and a processor that controls the communication module, wherein the processor receives downlink control information (DCI) via a physical downlink control channel (PDCCH) that instructs the scheduling information of the physical downlink shared channel (PDSCH) of one or more cells (rar), where at least one cell has a code block group (CBG)-based transmission configured, and identifies the transmission method in each cell based on the DCI format of the DCI, where the transmission method is either a transmission block (TB)-based transmission or a CBG-based transmission, and receives the PDSCH of each cell in the one or more cells (rar) based on the scheduling information of the PDCCH, and responds to the reception of the PDSCH of each cell with a HARQ-ACK (hybrid automatic repeat request) to the one or more cells (rar). An acknowledgement bit sequence is generated based on the identified transmission method of each cell, but within the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for TB-based transmission and the HARQ-ACK bit sequence for CBG-based transmission are generated separately, and a terminal is provided for transmitting the generated HARQ-ACK bit sequence.

[0017] Furthermore, according to embodiments of the present invention, a wireless communication method in a wireless communication system, comprising the steps of: receiving downlink control information (DCI) in one or more cells (rar) via a physical downlink control channel (PDCCH) that instructs the physical downlink sharing channel (PDSCH) scheduling information of each cell; in the one or more cells (rar), at least one cell is configured for code block group (CBG)-based transmission; identifying a transmission method in each cell based on the DCI format of the DCI, wherein the transmission method is either transmission block (TB)-based transmission or CBG-based transmission. A wireless communication method is provided, comprising the steps of: receiving the PDSCH of each cell in one or more cells (a) based on scheduling information of the PDCCH; generating a HARQ-ACK bit sequence for the one or more cells (a) in response to the reception of the PDSCH of each cell, based on the identified transmission method of each cell, wherein a HARQ-ACK bit sequence for TB-based transmission and a HARQ-ACK bit sequence for CBG-based transmission are each generated separately within the HARQ-ACK bit sequence; and transmitting the generated HARQ-ACK bit sequence.

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

[0019] In the one or more cells (ra) described above, if the number M of CBGs (ra) transmitted through a specific cell where CBG-based transmission is configured is less than N, then the HARQ-ACK bits (ra) for the specific cell consist of M HARQ-ACK bits (ra) and NM NACKs (ra) for the transmitted CBGs (ra).

[0020] The processor receives a downlink assignment index (DAI) in the DCI format and generates the HARQ-ACK bit sequence by referring to the DAI, the DAI including a counter-DAI indicating the cumulative number of PDSCHs scheduled up to the current cell and a total-DAI indicating the total number of PDSCHs scheduled to 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, respectively.

[0022] Within the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for the CBG-based transmission is attached after the HARQ-ACK bit sequence for the TB-based transmission.

[0023] Furthermore, according to another embodiment of the present invention, a terminal of a wireless communication system includes a communication module and a processor that controls the communication module, wherein the processor receives a physical downlink control channel (PDCCH) that instructs the scheduling information of the physical downlink shared channel (PDSCH) of one or more cells (etc.), and at least one of the one or more cells (etc.) is configured to enable code block group (CBG)-based transmission, receives a downlink assignment index (DAI) via the PDCCH, and based on the scheduling information of the PDCCH, the processor controls the scheduling information of each cell (etc.) A terminal is provided that receives a signal and generates a HARQ-ACK bit sequence for one or more cells (etc.) with reference to the DAI as a response to the reception of the PDSCH of each cell, wherein the HARQ-ACK bit sequence includes at least one of a HARQ-ACK bit sequence for a transmission block (TB)-underground transmission and a HARQ-ACK bit sequence for a CBG-underground transmission, and the DAI is applied separately to the HARQ-ACK bit sequence for the TB-underground transmission and the HARQ-ACK bit sequence for the CBG-underground transmission, respectively, and transmits the generated HARQ-ACK bit sequence.

[0024] Furthermore, according to another embodiment of the present invention, a wireless communication method in a wireless communication system, comprising the steps of: receiving a physical downlink control channel (PDCCH) instructing the scheduling information of the physical downlink shared channel (PDSCH) of one or more cells (rar); having at least one cell in the one or more cells (rar) configured to enable code block group (CBG)-based transmission; receiving a downlink assignment index (DAI) via the PDCCH; receiving the PDSCH of each cell in the one or more cells (rar) based on the scheduling information of the PDCCH; and receiving the PDSCH of each cell A wireless communication method is provided, comprising the steps of: generating a HARQ-ACK bit sequence for one or more cells in response to the above, with reference to the DAI; the HARQ-ACK bit sequence including at least one of a transmission block (TB)-underground transmission and a CBG-underground transmission, wherein the DAI is applied separately to the HARQ-ACK bit sequence for the TB-underground transmission and the HARQ-ACK bit sequence for the CBG-underground transmission; and transmitting the generated HARQ-ACK bit sequence.

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

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

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

[0028] In the one or more cells (ra) described above, if the number M of CBGs (ra) transmitted through a specific cell where CBG-based transmission is configured is less than N, then the HARQ-ACK bits (ra) for the specific cell consist of M HARQ-ACK bits (ra) and NM NACKs (ra) for the transmitted CBGs (ra).

[0029] Within the HARQ-ACK bit sequence, the HARQ-ACK bit sequence for the CBG-based transmission is attached after the HARQ-ACK bit sequence for the TB-based transmission.

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

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

[0032] The aforementioned pre-set value is the binary number "11".

[0033] The HARQ-ACK bit sequence is transmitted via the physical uplink shared channel (PUSCH). [Effects of the Invention]

[0034] According to embodiments of the present invention, the overhead of downlink control information that a terminal configured to enable CBG-based transmission refers to in determining the HARQ-ACK bit sequence can be minimized. Therefore, according to embodiments of the present invention, the network transmission efficiency between the base station and the terminal is increased.

[0035] Furthermore, according to embodiments of the present invention, the signaling overhead required to request retransmission can be minimized through efficient signaling in fallback mode.

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

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

[0038] The terminology used herein has been selected as widely used and general terms as possible, taking into account the function of the present invention; however, this may vary depending on the intent of the articulators, conventions, or the emergence of new technologies. In addition, in certain cases, the applicant has arbitrarily selected some terms, in which case their meaning will be described in the section describing the form of implementation of the invention. Therefore, it is important to clarify that the terminology used herein is not merely a set of names, but should be interpreted based on the substantive meaning of the term and the overall content of this specification.

[0039] Throughout the specification, when a configuration is described as being "connected" to another configuration, this includes not only cases where they are "adjustablely connected" but also cases where they are "electrically connected" with other components in between. Furthermore, when a configuration is described as "including" a particular component, this means, unless otherwise stated, that it includes other components rather than excluding them. In addition, limitations such as "greater than or equal to" or "less than or equal to" a specific critical value may be appropriately switched to "greater than" or "less than" respectively, depending on the embodiment.

[0040] The following technologies are used in a variety of radio access systems, such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA is implemented using radio technology such as UTRA (universal terrestrial radio access) and CDMA2000. TDMA is implemented using radio technology such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM (registered trademark) evolution). OFDMA is implemented using radio technology such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., WiMAX), IEEE 802-20, and E-UTRA (Evolved UTRA). UTRA is part of UMTS (universal mobile telecommunications system). 3GPP LTE (long term evolution) is part of E-UMTS (evolved UMTS) which uses E-UTRA, and LTE-A (LTE-advanced) is an advanced version of 3GPP LTE. It is a system designed separately from 3GPP NR LTE / LTE-A and is intended to support the eMBB (enhanced Broadband), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive Machine Type Communication) services required by IMT-2020.For the sake of clarity, the 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, the base station includes a gNB (next generation node B) defined in 3GPP NR. Also, unless otherwise specified, the 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 (or radio frame) used in a 3GPP NR system is 10 ms (Δf max N f / 100)*T c ) in length. Also, the radio frame consists of 10 subframes (subfame, SF) of equal size. Here, Δf max = 480 * 103 Hz, N f = 4096, T c = 1 / (Δf max * N f,ref ), Δf ref = 15 * 103 Hz, N f,ref = 2048. The 10 subframes within one frame are each assigned numbers 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 a 3GPP NR system is 15 * 2 μ kHz. μ is the subcarrier spacing configuration factor and has values of μ = 0 to 4. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 240 kHz is used as the subcarrier spacing. A 1 ms long subframe consists of 2 μ slots. At this time, the length of each slot is 2 -μ ms. The 2 μ slots within one subframe are each from 0 to 2 μNumbers are assigned from -1. Also, each slot within a single wireless frame is numbered from 0 to 10*2. μ A number up to -1 is assigned. Time resources are distinguished by at least one of the following: radio frame number (also called radio frame index), subframe number (also called subframe index), or slot number (also called slot index).

[0043] Figure 2 shows an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, Figure 2 shows the resource grid structure of a 3GPP NR system. There is one resource grid per antenna port. Referring to Figure 2, a slot contains multiple OFDM symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. An OFDM symbol may also mean a single symbol interval. Unless otherwise specified, an OFDM symbol is simply referred to as a symbol. Referring to Figure 2, the signal transmitted from each slot is N size、μ grid、x *N RB SC individual subcarriers and N slot symb It is represented by a resource grid consisting of n OFDM symbols. Here, if it is a downlink resource grid, x=DL, and if it is an uplink resource grid, x=UL. size、μ grid、x This indicates the number of resource blocks (RBs) due to the subcarrier spacing component μ (where x is DL or UL), and N slot symb This indicates the number of OFDM symbols in the slot. RB SC N is the number of subcarriers that make up one RB. RB SC = 12. OFDM symbols are also called CP-OFDM (cyclic prefix OFDM) symbols or DFT-S-OFDM (discrete Fourier transform spread OFDM) symbols depending on the multiple access method.

[0044] The number of OFDM symbols in a single slot can vary depending on the length of the cyclic prefix (CP). For example, a normal CP may contain 14 OFDM symbols in a single slot, while an extended CP may contain 12 OFDM symbols in a single slot. In specific embodiments, extended CPs are used only at a subcarrier interval of 60 kHz. For the sake of explanation, Figure 2 illustrates a case where a single slot consists of 14 OFDM symbols, but the embodiments of the present invention can be applied in the same manner to slots with OFDM symbols of other lengths. Referring to Figure 2, each OFDM symbol has N in the frequency domain. size、μ grid、x *N RB SC It contains multiple subcarriers. Subcarriers can be 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 in the frequency domain. RB SC It is defined as a sequence of (for example, 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 It consists of n resource elements. Each resource element in the resource grid is uniquely defined by an index pair (k, l) in a single slot, where k is 0 to N in the frequency domain. size、μ grid、x *N RB SC An index given up to -1, where 1 is in the time domain and ranges from 0 to N. slot symb This is an index given down to -1.

[0046] For a terminal to receive or transmit signals from a base station, its time / frequency synchronization must be synchronized with that of the base station. Without this synchronization, the terminal cannot determine the necessary time and frequency parameters for accurate timing of DL signal demodulation and UL signal transmission.

[0047] Each symbol in a radio frame operating in TDD (time division duplex) or unpaired spectrum consists of at least one of the following: a downlink symbol (DL symbol), an uplink symbol (UL symbol), or a flexible symbol. In FDD (frequency division duplex) or paired spectrum, a radio frame operating on a downlink carrier consists of either a downlink symbol or a flexible symbol, while a radio frame operating on an uplink carrier consists of either an uplink symbol or a flexible symbol. Downlink symbols can be used for downlink transmission but not uplink transmission, and uplink symbols can be used for uplink transmission but not downlink transmission. The use of a flexible symbol in the downlink or uplink is determined by 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 additionally of a UE-specific (or dedicated) RRC signal. The base station uses the cell-specific RRC signal to notify (i) the period of the cell-specific slot configuration, (ii) the number of slots having only downlink symbols from the beginning of the 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 means of 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 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 symbol consisting of the RRC signals described above is called a semi-static DL / UL configuration. In the semi-static DL / UL configuration consisting of the RRC signals described above, the flexible symbol is indicated as a downlink symbol, uplink symbol, or flexible symbol via dynamic SFI (slot format information) transmitted over the physical downlink control channel (PDCCH). In this case, the downlink symbol or uplink symbol consisting of the RRC signals is not changed to another symbol type. Table 1 shows an example of dynamic SFI that a base station instructs a terminal.

[0051] [Table 1]

[0052] In Table 1, D represents the downlink symbol, U represents the uplink symbol, and X represents the flexible symbol. As shown in Table 1, a maximum of two DL / UL switching operations are permitted in a single slot.

[0053] Figure 3 illustrates the physical channels used in 3GPP systems (e.g., NR) and a typical signal transmission method using these physical channels. When a terminal is powered on or enters a new cell, the terminal performs an initial cell discovery operation (S101). Specifically, the terminal synchronizes with the base station during the initial cell discovery. To do this, 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 obtain information such as the cell ID. Next, the terminal receives a physical broadcast channel from the base station and obtains broadcast information within the cell.

[0054] S102 A terminal that has completed its task receives a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) via the information carried on the PDCCH, thereby obtaining more detailed system information than the system information obtained via the initial cell terminal.

[0055] If the terminal first accesses the base station or does not have radio resources to transmit a signal, the terminal performs an arbitrary access process 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 for the preamble from the base station via PDCCH and the corresponding PDSCH S104. If the terminal receives a valid random access response message, the terminal transmits data including its identifier to the base station via a physical uplink shared channel (PUSCH) instructed by the uplink grant transmitted from the base station via PDCCH S105. Next, the terminal waits to receive a PDCCH as instructed by the base station to resolve collisions S106, and the random access process ends.

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

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

[0058] Refer to Figure 4(a) for a more detailed explanation of the synchronization signal (SS). The synchronization signal is divided into PSS and SSS. PSS is used to obtain time-domain synchronization and / or frequency-domain synchronization, such as OFDM symbol synchronization and slot synchronization. SSS is used to obtain frame synchronization and cell group ID. Referring to Figure 4(a) and Table 2, an SS / PBCH block consists of 20 RBs (=240 subcarriers) consecutively on the frequency axis and 4 OFDM symbols consecutively on the time axis. In this case, within the SS / PBCH block, the PSS is transmitted via subcarriers 56-182 in the first OFDM symbol, and the SSS is transmitted via subcarriers 56-182 in the third OFDM symbol. Here, the lowest subcarrier index of the SS / PBCH block is assigned starting from 0. In the first OFDM symbol on which the PSS is transmitted, the base station does not transmit signals via the remaining subcarriers, i.e., subcarriers 0-55 and 183-239. Furthermore, in the third OFDM symbol in which the SSS is transmitted, the base station does not transmit signals via subcarriers 48-55 and 183-191. In the SS / PBCH block, the base station transmits the PBCH (physical broadcast channel) via the remaining REs excluding the aforementioned signals.

[0059] [Table 2]

[0060] The SS generates a total of 1008 unique physical layer cell IDs through combinations of three PSSs and SSSs. More specifically, each physical layer cell ID is part of only one physical layer cell identifier group, and each group is grouped into 336 physical layer cell identifier groups, each containing three unique identifiers. Thus, the physical layer cell ID is... cell ID =3N (1) ID +N (2) IDThis is an index N ranging from 9 to 335 that represents a physical-hierarchical cell-identifier group. (1) ID And, an index N from 0 to 2 indicating a physical-hierarchical identifier within the physical-hierarchical cell-identifier group. (2) ID It is uniquely defined by [the system]. The terminal detects the PSS and identifies one of three unique physical-hierarchy identifiers. The terminal also detects the SSS and identifies one of 336 physical-hierarchy cell IDs associated with the physical-hierarchy identifier. In this case, the sequence d of the PSS PSS (n) is as follows:

[0061]

number

[0062] Here,

number

number

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

number

[0064] Here,

number

number

[0065] A 10ms long wireless frame is divided into two 5ms long half-frames. Refer to Figure 4(b) to describe the slot in which the SS / PBCH block is transmitted within each half-frame. The slot in which the SS / PBCH block is transmitted is one of cases A, B, C, D, or E. In case A, the subcarrier spacing is 15kHz, and the start of the SS / PBCH block is at the {2, 8} + 14*n symbol. In this case, n=0, 1 at carrier frequencies below 3GHz. Also, n=0, 1, 2, 3 at carrier frequencies above 3GHz and below 6GHz. In case B, the subcarrier spacing is 30kHz, and the start of the SS / PBCH block is at the {4, 8, 16, 20} + 28*n symbol. In this case, n=0 at carrier frequencies below 3GHz. Also, n=0, 1 at carrier frequencies above 3GHz and below 6GHz. In Case C, the subcarrier spacing is 30 kHz, and the SS / PBCH block starts at the {2nd, 8th} + 14*nth symbol. In this case, for carrier frequencies below 3 GHz, n=0, 1. Also, for carrier frequencies above 3 GHz and below 6 GHz, n=0, 1, 2, 3. In Case D, the subcarrier spacing is 120 kHz, and the SS / PBCH block starts at the {4th, 8th, 16th, 20th} + 28*nth symbol. In this case, for carrier frequencies above 6 GHz, n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In Case E, the subcarrier spacing is 240 kHz, and the SS / PBCH block starts at the {8th, 12th, 16th, 20th, 32nd, 36th, 40th, 44th} + 56*nth symbol. In this case, at carrier frequencies of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0066] Figure 5 shows the procedure for transmitting control information and control channels in a 3GPP NR system. Referring to Figure 5(a), the base station adds a CRC (cyclic redundancy check) masked (e.g., by XOR operation) with an RNTI (radio network temporary iedntifier) ​​to the control information (e.g., DCI) S202. The base station scrambles the CRC with an RNTI value determined according to the purpose / target of each piece of control information. A common RNTI used by one or more terminals includes at least one of SI-RNTI (system information RNTI), P-RNTI (paging RNTI), RA-RNTI (random access RNTI), and TPC-RNTI (transmit power control RNTI). Additionally, terminal-specific RNTIs include at least one of C-RNTI (cell temporary RNTI) and CS-RNTI. Next, after channel encoding (e.g., polar coding) in S204, the base station performs rate matching in S206 to match the amount of resources used for PDCCH transmission. Then, based on the PDCCH structure with control channel elements (CCEs), the base station multiplexes the DCIs (DCIs) in S208. The base station also applies additional processes such as scrambling, modulation (e.g., QPSK), and interleaving in S210 to the multiplexed DCIs (DCIs) and maps them to the resources to be transmitted. A CCE is the basic unit for a PDCCH, and one CCE consists of multiple (e.g., six) resource element groups (REGs). One REG consists of multiple (e.g., twelve) resource elements (REs). The number of CCEs used for one PDCCH is defined as the aggregation level. In 3GPP NR systems, aggregation levels of 1, 2, 4, 8, or 16 are used. Figure 5(b) is a diagram relating to the CCE integration level and PDCCH multiplexing, showing the types of CCE integration levels used for a single PDCCH and the CCEs transmitted in the control domain thereunder.

[0067] Figure 6 shows a CORESET (control resource set) on which the PDCCH (physical downlink control channel) is transmitted in a 3GPP NR system. A CORESET is a time-frequency resource on which the PDCCH, which is a control signal for a terminal, is transmitted. Furthermore, the search space, which will be described later, is mapped to a single CORESET. Therefore, instead of monitoring the entire frequency band to receive the PDCCH, the terminal monitors the CORESET and the designated time-frequency domain to decode the PDCCH mapped to the CORESET. The base station configures one or more CORESETs per cell for the terminal. A CORESET consists of up to three consecutive symbols on the time axis. Also, a CORESET consists of six consecutive PRB units on the frequency axis. In the embodiment of Figure 5, CORESET#1 consists of consecutive PRBs, and CORESET#2 and CORESET#3 consist of discontinuous PRBs. A CORESET can be located in any symbol within a slot. For example, in the embodiment shown in Figure 5, CORESET#1 starts from the first symbol in the slot, CORESET#2 starts from the fifth symbol in the slot, and CORESET#9 starts from the ninth symbol in the slot.

[0068] Figure 7 shows a method for configuring the PDCCH search space in a 3GPP NR system. Each CORESET has at least one search space for transmitting PDCCHs to terminals. In embodiments of the present invention, the search space is a collection of all time-frequency resources (hereinafter referred to as PDCCH candidates) to which the terminal's PDCCH is transmitted. The search space includes a common search space that all 3GPP NR terminals should search in common, and terminal-specific or UE-specific search spaces that specific terminals should search. The common search space monitors PDCCHs that all terminals in a cell belonging to the same base station should search in common. The terminal-specific search spaces are configured terminal-specific, monitoring the PDCCHs assigned to each terminal at different locations within the search space depending on the terminal. In the case of terminal-specific search spaces, due to the limited control area to which PDCCHs are assigned, the search spaces between terminals may partially overlap. Monitoring PDCCHs involves blind decoding PDCCH candidates within the search space. If blind decoding is successful, it is expressed as the PDCCH being (successfully) detected / received. If blind decoding fails, it is expressed as the PDCCH not being detected / received, or not being successfully detected / received.

[0069] For the sake of explanation, a PDCCH scrambled with a group common (GC) RNTI already known by one or more terminals for the purpose of transmitting downlink control information to one or more terminals is referred to as a group common (GC) PDCCH or common PDCCH. Furthermore, a PDCCH scrambled with a terminal-specific RNTI already known by a specific terminal for the purpose of transmitting uplink scheduling information or downlink scheduling information to a specific terminal is referred to as a terminal-specific PDCCH. The common PDCCH is included in the common search space, and the terminal-specific PDCCH is included in either the common search space or the terminal-specific PDCCH.

[0070] The base station informs a terminal or group of terminals via the PDCCH about resource allocation information for the transmission channels PCH (paging channel) and DL-SCH (downlink-shared channel) (i.e., DL Grant), or information about UL-SCH resource allocation and HARQ (hybrid automatic repeat request) (i.e., UL Grant). The base station transmits PCH transmission blocks and DL-SCH transmission blocks via the PDSCH. The base station transmits data excluding specific control information or specific service data via the PDSCH. The terminal also receives data excluding specific control information or specific service data via the PDSCH.

[0071] The base station transmits the PDCCH containing information about which terminals (one or more terminals) the PDSCH data will be transmitted to and how those terminals should receive and decode the PDSCH data. For example, suppose a DCI transmitted to a specific PDCCH is CRC masked to an RNTI named "A," and that DCI indicates that the PDSCH is assigned to a radio resource (e.g., frequency location) named "B," and also indicates transmission format information (e.g., transmission block size, modulation scheme, coding information, etc.) named "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 the "A" RNTI, that terminal will receive the PDCCH and, through the information of the received PDCCH, receive the PDSCH indicated by "B" and "C."

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

[0073] [Table 3]

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

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

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

[0077] -CSI: This is feedback information for the downlink channel. It is generated by the terminal based on the CSI-RS (reference signal) transmitted by the base station. MIMO (multiple input multiple output) related feedback information includes RI and PMI. CSI is divided into CSI Part 1 and CSI Part 2 depending on the information it indicates.

[0078] The 3GPP NR system uses five PUCCH formats to support diverse service scenarios, diverse channel environments, and frame structures.

[0079] PUCCH format 0 is a format for transmitting 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 is transmitted via one or two OFDM symbols on the time axis and one RB on the frequency axis. If PUCCH format 0 is transmitted via two OFDM symbols, the same sequence is transmitted to the two symbols with different RBs. Through this, the terminal obtains a frequency diversity gain. More specifically, the terminal is M bit Bit UCI(M bit The value of the cyclic shift m depends on whether it is =1 or 2. cs Determine the base sequence of length 12 and set the value m cs The cyclically shifted sequence is mapped to 12 REs, consisting of one OFDM symbol and one PRB, and transmitted. The terminal has 12 cyclic shifts available, M bit If = 1, then 1-bit UCI0 and 1 represent a sequence of two cyclic shifts with a difference of 6 in cyclic shift values. Also, M bit If = 2, then the 2-bit UCI00, 01, 11, and 10 represent a sequence of four cyclic shifts where the difference in cyclic shift values ​​is 3.

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

[0081] PUCCH format 2 transmits UCI exceeding 2 bits. PUCCH format 2 is transmitted via one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. If PUCCH format 2 is transmitted via two OFDM symbols, the same sequence is transmitted via the two OFDM symbols with different RBs. Through this, the terminal obtains frequency diversity gain. For more details, see M bit Bit UCI(M bit >2) is bit-level scrambled and QPSK modulated and mapped to the RB(ar) of one or two OFDM symbols(ar), where the number of RBs is one between 1 and 16.

[0082] PUCCH format 3 or PUCCH format 4 transmits UCIs exceeding 2 bits. PUCCH format 3 or PUCCH format 4 is transmitted via 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. For more details, see the terminal. bit Bit UCI(M bit>2) Modulate with π / 2-BPSK (Binary Phase Shift Keying) or QPSK, and complex number symbols d(0)~d(M symb -1) is generated. Here, if we use π / 2-BPSK, M symb =M bit And, if you use QPSK, symb =M bit The value is / 2. The terminal does not apply block-unit spreading to PUCCH format 3. However, the terminal may apply block-unit spreading to one RB (i.e., 12 subcarriers) using a PreDFT-OCC of length -12 so that PUCCH format 4 has two or four multiplexing capacities. The terminal transmits the spread signal by transmit precoding (or DFT-precoding) and mapping it to each RE.

[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 the UCI transmitted by the terminal and the maximum code rate. If the terminal uses PUCCH format 2, it 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 will not transmit some of the UCI information according to the priority of the UCI information, and will transmit only the remaining UCI information.

[0084] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured via an RRC signal to instruct frequency hopping within a slot. When frequency hopping is configured, the index of the RB to be frequency-hopped is determined by the RRC signal. If PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted over N OFDM symbols in the time axis, the first hop will have floor(N / 2) OFDM symbols, the second hop will have ceil(N / 2) OFDM symbols.

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

[0086] On the other hand, in the 3GPP NR system, terminals transmit and receive using a bandwidth smaller than or equal to the carrier (or cell) bandwidth. For this purpose, terminals are configured with a bandwidth part (BWP) consisting of a continuous portion of the carrier bandwidth. Terminals operating according to TDD or in the ampered spectrum have up to four DL / UL BWP pairs per carrier (or cell). The terminal also activates one DL / UL BWP pair. Terminals operating according to FDD or in the paired spectrum have up to four DL BWPs configured on the downlink carrier (or cell) and up to four UL BWPs configured on the uplink carrier (or cell). The terminal activates one DL BWP and one UL BWP per carrier (or cell). The terminal does not have to receive or transmit from time-frequency resources other than the activated BWPs. The activated BWPs are called active BWPs.

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

[0088] Figure 8 is a conceptual diagram illustrating carrier aggregation. Carrier aggregation refers to a method by which a wireless communication system uses multiple frequency blocks, or (logical) cells, consisting of uplink resources (or component carriers) and / or downlink resources (or component carriers), to utilize a wider frequency band within a single larger logical frequency band. For convenience of explanation, the term "component carrier" will be used consistently below.

[0089] Referring to Figure 8, as an example of a 3GPP NR system, the overall system bandwidth includes up to 16 component carriers, each component carrier having a bandwidth of up to 400 MHz. Each component carrier includes one or more physically consecutive subcarriers. Although Figure 8 shows each component carrier having the same bandwidth, this is merely illustrative, and each component carrier may have different bandwidths. Also, although each component carrier is shown as being adjacent to each other on the frequency axis, the diagram is a logical representation, and each component carrier may be physically adjacent to or far from each other.

[0090] Each component carrier uses a different center frequency. Furthermore, physically adjacent component carriers share a single common center frequency. In the embodiment shown in Figure 8, assuming all component carriers are physically adjacent, center frequency A is used for all component carriers. If we assume that the component carriers are not physically adjacent, then center frequencies A and B are used for each component carrier.

[0091] When the overall system bandwidth is expanded through carrier aggregation, the frequency band used for communication with each terminal is defined on a component carrier basis. Terminal A uses the overall system bandwidth of 100 MHz and communicates using all five component carriers. Terminals B1 to B5 use only a 20 MHz bandwidth and communicate using one component carrier each. Terminals C1 and C2 use only a 40 MHz bandwidth and communicate using two component carriers each. The two component carriers may be logically / physically adjacent or not. In the embodiment shown in Figure 8, terminal C1 uses two non-adjacent component carriers, and terminal C2 uses two adjacent component carriers.

[0092] Figure 9 illustrates single-carrier and multiple-carrier communication. Specifically, Figure 9(a) shows the subframe structure of a single-carrier system, and Figure 9(b) shows the subframe structure of a multiple-carrier system.

[0093] Referring to Figure 9(a), a typical wireless communication system, in FDD mode, transmits or receives data via one DL band and its corresponding UL band. In other specific embodiments, in TDD mode, the wireless communication system divides the wireless frame into uplink time units and downlink time units in the time domain, and transmits or receives data via the uplink / downlink time units. Referring to Figure 9(b), three 20MHz component carriers (CCs) are aggregated in both the UL and DL bands, supporting a 60MHz bandwidth. Each CC is either adjacent or non-adjacent to the others in the frequency domain. For convenience, Figure 9(b) shows a symmetrical case where the bandwidths of the UL CCs and DL CCs are the same, but the bandwidths of each CC may be determined independently. Asymmetric carrier aggregations with different numbers of UL CCs and DL CCs are also possible. A DL / UL CC assigned / configured to a specific terminal via RRC is referred to as the serving DL / UL CC of that terminal.

[0094] A base station communicates with a terminal by activating some or all of the terminal's serving CCs, or by deactivating some of the CCs. The base station may change which CCs are activated / deactivated, or change the number of CCs that are activated / deactivated. Once a base station assigns available CCs to a terminal on a cell-specific or terminal-specific basis, at least one of the initially assigned CCs does not need to be deactivated unless the CC assignment to the terminal is completely reconfigured or the terminal is handed over. The CC that is not deactivated by the terminal is called the primary CC (PCC) or PCell (primary cell), and the CC that the base station can freely activate / deactivate is called the secondary CC (SCC) or SCell (secondary cell).

[0095] On the other hand, 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 the DL resource (or DL ​​CC) and the carrier frequency of the UL resource (or UL CC) is indicated by system information. Carrier frequency refers to the center frequency of each cell or CC. A cell corresponding to a PCC is called a PCell, and a cell corresponding to an SCC is called a SCell. In the downlink, the carrier corresponding to a PCell is a DL PCC, and in the uplink, the carrier corresponding to a PCell is a UL PCC. Similarly, in the downlink, the carrier corresponding to a SCell is a DL SCC, and in the uplink, the carrier corresponding to a SCell is a UL SCC. Depending on the terminal capacity, a serving cell consists of one PCell and zero or more SCells. If the RRC_CONNECTED state exists but carrier aggregation is not configured, or if the UE does not support carrier aggregation, there will be only one serving cell consisting solely of PCells.

[0096] As described above, the term "cell" used in carrier aggregation is distinct from the term "cell" which refers to a specific geographical area where communication services are provided by a single base station or antenna group. To distinguish between a cell referring to a specific geographical area and a cell in carrier aggregation, this invention refers to a cell in carrier aggregation as CC and a cell referring to a geographical area as cell.

[0097] Figure 10 shows an example where the cross-carrier scheduling technique is applied. Once cross-carrier scheduling is set up, the control channel transmitted through the first CC uses the carrier indicator field (CIF) to schedule the data channel transmitted through the first or second CC. The CIF is contained within the DCI. In other words, a scheduling cell is set up, and DL grants / UL grants transmitted from the PDCCH region of the scheduling cell schedule the PDSCH / PUSCH of the scheduled cell. That is, there is a PDCCH region of a scheduled cell with grinding regions for multiple component carriers. A PCell is essentially a scheduling cell, and a particular SCell is designated as a scheduling cell by a higher hierarchy.

[0098] In the embodiment shown in Figure 10, we revise the assumption that three DL CCs are merged. Here, we assume that DL component carrier #0 is DL PCC (or PCell), and DL component carriers #1 and #2 are DL SCC (or SCell). We also assume that DL PCC is configured as a PDCCH monitoring CC. If cross-carrier scheduling is not configured by terminal-specific (or terminal-group-specific, or cell-specific) higher-level signaling, the CIF will be disabled, and each DL CC will transmit only PDCCHs that schedule their own PDSCH without a CIF according to the NR PDCCH rules (non-cross-carrier scheduling, self-carrier scheduling). In contrast, if cross-carrier scheduling is configured through terminal-specific (or terminal-group-specific, or cell-specific) higher-level signaling, the CIF becomes ensable, and a specific CC (e.g., DL PCC) uses the CIF to transmit not only the PDCCH that schedules the PDSCH of DL CC A, but also the PDCCH that schedules the PDSCH of other CCs (cross-carrier scheduling). In contrast, other DL CCs do not transmit PDCCH. Therefore, depending on whether cross-carrier scheduling is configured for the terminal, the terminal either monitors PDCCHs without the CIF and receives self-carrier scheduled PDSCHs, or monitors PDCCHs with the CIF and receives cross-carrier scheduled PDSCHs.

[0099] On the other hand, Figures 9 and 10 illustrate the subframe structure of a 3GPP LTE-A system, and the same or similar configurations are applicable to a 3GPP NR system. However, in a 3GPP NR system, the subframes in Figures 9 and 10 are switched to slots.

[0100] Figure 11 shows the configuration of a code block group (CBG) according to an embodiment of the present invention and its time-frequency resource mapping. More specifically, Figure 11(a) shows one embodiment of the CBG configuration included in a single transmission block (TB), and Figure 11(b) shows the time-frequency resource mapping of the said CBG configuration.

[0101] Channel codes have a defined maximum supported length. For example, the maximum supported length of Turbo Code used in 3GPP LTE(-A) is 6144 bits. However, the length of a transmission block (TB) transmitted in a PDSCH may be longer than 6144 bits. If the length of a TB is longer than the maximum supported length, the TB is divided into code blocks (CBs) of up to 6144 bits in length. Each CB is the unit in which channel coding is performed. Additionally, for efficient retransmission, several CBs may be bundled together to form a CBG. Terminals and base stations need information on how the CBG is configured.

[0102] Within a TB, CBGs and CBs can be configured in various ways. In one embodiment, the number of usable CBGs is determined to a fixed value, or is 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 CBGs are set according to the predetermined number information. In another embodiment, the number of CBs contained in a single CBG may be determined to a fixed value, or may be 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 of CBs per CBG information.

[0103] Referring to the embodiment in Figure 11(a), one TB is divided into eight CBs. The eight CBs are further bundled into four CBGs. Such a mapping relationship between CBs and CBGs (or CBG configuration) is set statically between the base station and the terminal, or semi-statically in the RRC configuration information. According to other embodiments, the mapping relationship is set via dynamic signaling. When the terminal receives the PDCCH transmitted by the base station, the terminal directly or indirectly identifies the mapping relationship between CBs and CBGs (or CBG configuration) through direct and / or implicit information. A single CBG may contain only one CB, or it may contain all the CBs that make up a single TB. Incidentally, the technique proposed in the embodiments of the present invention is applicable regardless of the CB and CBG configuration.

[0104] Referring to Figure 11(b), the CBGs constituting a single TB are mapped to the time-frequency resources scheduled by the PDSCH. In one embodiment, each CBG is first assigned to the frequency axis and then extended to the time axis. If a PDSCH consisting of one TB containing four CBGs is assigned to seven OFDM symbols, then 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 time-frequency mapping relationships assigned between CBGs and PDSCHs are determined between the terminals. However, the mapping relationships shown in Figure 11(b) are one embodiment for illustrating the present invention, and the techniques proposed in the embodiments of the present invention may be applied independently of the time-frequency mapping relationships of the CBGs.

[0105] Figure 12 illustrates the process by which a base station performs TB-based transmission or CBG-based transmission, and a terminal transmits a HARQ-ACK in response. Referring to Figure 12, the base station configures a transmission method suitable for the terminal, either TB-based transmission or CBG-based transmission. The terminal transmits the HARQ-ACK bits(s) according to the transmission method configured by the base station to the PUCCH or PUSCH. The base station configures a PDCCH to schedule the PDSCH to be transmitted to the terminal. The PDCCH schedules TB-based transmission and / or 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. 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 through one PDSCH, and if the MIMO transmission rank or layer is high, two TBs are transmitted through one PDSCH.

[0106] The terminal transmits a 1-bit TB-based HARQ-ACK per TB to inform the base station whether each TB was successfully received. To generate a HARQ-ACK for a TB, the terminal checks for reception errors for that TB via TB-CRC. If the TB-CRC check for a TB is successful, the terminal generates an ACK for the TB's HARQ-ACK. However, if a TB-CRC error occurs for a TB, the terminal generates a NACK for the TB's HARQ-ACK. The terminal transmits these generated TB-based HARQ-ACKs to the base station. The base station retransmits the TBs for which a NACK was responded from the TB-based HARQ-ACKs received from the terminal.

[0107] Furthermore, the terminal transmits a 1-bit CBG-based HARQ-ACK for each CBG to inform the base station whether each CBG was successfully received. To generate a HARQ-ACK for a single CBG, the terminal decodes all CBs contained in the CBG and checks for reception errors for the relevant CBs via CB-CRC. If the terminal successfully receives all CBs constituting a single CBG (i.e., all CB-CRC checks are successful), the terminal generates an ACK for the HARQ-ACK of that CBG. However, if the terminal fails to successfully receive at least one of the CBs constituting a single CBG (i.e., at least one CB-CRC error occurs), the terminal generates a NACK for the HARQ-ACK of that CBG. The terminal transmits these generated CBG-based HARQ-ACKs to the base station. The base station retransmits the CBGs for which a NACK was responded from the CBG-based HARQ-ACKs received from the terminal. According to one embodiment, the CB configuration of the retransmitted CBG is the same as the CB configuration of the conventionally transmitted CBG. The length of the CBG-based HARQ-ACK bits transmitted by the terminal to the base station is determined based on the number of CBGs transmitted via the PDSCH, or the maximum number of CBGs consisting of RRC signals. In addition, as in the embodiment described above, a TB-based HARQ-ACK may be transmitted separately from the CBG-based HARQ-ACK. In this case, the TB-based HARQ-ACK indicates whether or not the TB-CRC check was successful.

[0108] According to an embodiment of the present invention, CBG-based HARQ-ACK feedback is used for successful TB transmission. The base station instructs the terminal to transmit CBG-based HARQ-ACK. In this case, a retransmission technique using CBG-based HARQ-ACK is used. CBG-based HARQ-ACK is transmitted via PUCCH. Alternatively, if UCI is configured to be transmitted via PUCCH, CBG-based HARQ-ACK may be transmitted via the corresponding PUCCH. In PUCCH, the setting of HARQ-ACK resources is configured via RRC signals. Furthermore, the HARQ-ACK resources to be actually transmitted are indicated via PDCCH, which schedules PDSCH transmitted in the CBG-based system. The terminal transmits HARQ-ACK(etc.) regarding the success or failure of receiving the transmitted CBG via one or more PUCCH resources indicated via PDCCH from among the PUCCH resources consisting of RRC.

[0109] The base station identifies whether the terminal successfully received the CBG(etc.) transmitted to the terminal via the terminal's CBG-based HARQ-ACK feedback. In other words, the base station recognizes which CBG(etc.) the terminal successfully received and which CBG(etc.) the terminal failed to receive, based on the received CBG-based HARQ-ACK. More specifically, the base station bundles and retransmits only the CBG(etc.) that received a failed HARQ-ACK in a single TB. At this time, CBG(etc.) that received a successful HARQ-ACK are excluded from retransmission. The base station schedules the retransmitted CBG(etc.) into a single PDSCH and transmits them to the terminal.

[0110] The number of CBGs transmitted via the PDSCH may vary during the CBG retransmission process for transmitting a single TB. Therefore, the terminal needs to transmit whether it successfully received the CBGs transmitted from the relevant PDSCH via HARQ-ACK. However, the terminal does not need to transmit HARQ-ACKs for CBGs that have already received an ACK from the base station and have not been retransmitted from the relevant PDSCH. As described above, the number of HARQ-ACK bits 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 CBGs corresponding to other TBs of the same terminal, thereby reducing the overhead of the uplink control channel. However, despite the advantages mentioned above, the method of sending HARQ-ACK bits according to the number of CBGs transmitted from the PDSCH may have disadvantages in the following two situations.

[0111] i) After a terminal transmits a PUCCH (or a PUSCH containing a HARQ-ACK) that transmits a HARQ-ACK, the base station generates a NACK-to-ACK error. In this case, the base station determines that it has successfully transmitted the CBG(etc.) that should be retransmitted and does not transmit it via the next PDSCH for retransmission. The terminal expects the CBG(etc.) that it failed to receive to be retransmitted, but since the CBG(etc.) is not transmitted via the next PDSCH, it requests the transmission of a NACK(etc.) to retransmit the CBG(etc.). However, since the CBG(etc.) is not transmitted via the next PDSCH for retransmission, the terminal is unable to retransmit the HARQ-ACK for the CBG(etc.). Therefore, a method is needed to rectify the NACK-to-ACK error that may occur when a terminal transmits a PUCCH (or a PUSCH containing a HARQ-ACK) that transmits a HARQ-ACK.

[0112] ii) In CBG-based transmission, the terminal determines whether it has successfully received the CBG based on the success or failure of the CRC check of the CBs included in the CBG. 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 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 CBG. However, whether or not a TB has been successfully received is determined by the success or failure of the TB-CRC check attached to the TB. Therefore, the terminal may determine that it has successfully received all CBGs and transmit an ACK as a HARQ-ACK corresponding to the CBG, but there is a risk that it may fail to receive the TB due to a failure in the TB-CRC check. Therefore, a method is needed to improve this situation.

[0113] According to an embodiment of the present invention, a fallback indicator is used as a method to solve the problems that may occur when using a method that transmits HARQ-ACK bits in accordance with the number of CBGs transmitted from the PDSCH. The fallback indicator is an indicator that causes all CBGs of one TB to be retransmitted via the PDSCH (hereinafter referred to as fallback mode). The terminal generates a fallback indicator according to the following embodiment and transmits the fallback indicator together with the HARQ-ACK via the 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 referred to as "fallback mode request" and the second state is referred to as "non-fallback request". "Feedback mode request" is a state in which the retransmission of all CBGs of one TB is requested, and "non-fallback request" is a state in which the retransmission of all CBGs as described above is not requested. According to an additional embodiment of the present invention, the fallback indicator is also used as TB-based HARQ-ACK. Specific examples of TB-based HARQ-ACK will be described later.

[0114] According to one embodiment of the present invention, a terminal configured to operate on a CBG-based system has only one CBG configured for each TB. That is, all CBs contained in one TB are configured in one CBG. In this case, the HARQ-ACK feedback transmitted by the terminal is determined according to the success or failure of the TB-CRC. That is, if the TB-CRC check is successful, the terminal transmits an ACK as the HARQ-ACK to the corresponding CBG, and if the TB-CRC check fails, the terminal transmits a NACK as the HARQ-ACK to the corresponding CBG. In this case, whether or not fallback mode can be performed is determined from the ACK / NACK to the CBG without the explicit transmission of a fallback indicator. More specifically, a terminal that expects operation in fallback mode transmits a NACK as the HARQ-ACK to the CBG. If the base station receives a NACK as the HARQ-ACK from the terminal, it determines that fallback mode is necessary and thereby retransmits all CBGs of the corresponding TB via the PDSCH.

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

[0116] First, N CBGs (i.e., all CBGs) for a single TB are transmitted via PDSCH. In this case, the terminal determines whether it has successfully received each CBG via CB-CRC and transmits HARQ-ACKs for the N CBGs via the previously configured or instructed PUCCH resource. If the terminal successfully checks all CB-CRCs included in each CBG, it transmits an ACK as the HARQ-ACK for that CBG. Otherwise, the terminal transmits a NACK as the HARQ-ACK for that CBG. The HARQ-ACK for the CBG is transmitted via the HARQ-ACK in the PUCCH or PUSCH transmitted by the terminal. The base station bundles the CBGs for which the terminal has responded with a NACK and retransmits them via PDSCH. In this case, the feasibility of performing fallback mode is determined from the ACK / NACK for the CBG without the explicit transmission of a fallback indicator. More specifically, a terminal that desires to operate in fallback mode transmits a NACK as the HARQ-ACK for the CBG. If a terminal transmits a NACK as a HARQ-ACK to all CBGs, the base station will determine that fallback mode is necessary and will retransmit all CBGs of the corresponding TB via the PDSCH.

[0117] Table 4 shows the HARQ-ACK feedback transmitted by the terminal and the resulting operation when N=2. 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 feedback mode. Therefore, the base station bundles the first and second CBGs and retransmits them via the PDSCH.

[0118] [Table 4]

[0119] Next, for a natural number M less than N, M CBGs (i.e., a portion of CBGs) for one TB are transmitted via PDSCH. Once a portion of the CBGs for one TB have been transmitted, the terminal transmits the fallback indicator and HARQ-ACK as shown in the following embodiment. In each embodiment, redundant explanations are omitted for parts that are the same as or corresponding to the previous embodiment.

[0120] According to the first embodiment of the present invention, the terminal transmits an M+1 bit, which is a bundle of ACK / NACK bits and a 1-bit fallback indicator for each of the M CBGs, via a HARQ-ACK resource. At this time, priority is given to the 1-bit fallback indicator from the M-bit HARQ-ACK, and the feasibility of performing the fallback mode is determined. The terminal determines whether each transmitted CBG has been successfully received via CB-CRC. More specifically, since up to N CBGs may be transmitted to the terminal, the terminal is allocated a PUCCH resource capable of accommodating N HARQ-ACK bits. The terminal transmits 1 to N HARQ-ACK bits via this resource. The terminal bundles the 1-bit fallback indicator together with the M-bit HARQ-ACK using the HARQ-ACK resource and transmits an (M+1)-bit feedback. The base station receives (M+1)-bit feedback via the PUCCH resource of PUCCH or PUSCH transmitted from the terminal, thereby obtaining an M-bit HARQ-ACK and a fallback indicator for the transmitted CBG.

[0121] Figure 13 shows one example of how to interpret the received HARQ-ACK feedback and fallback indicator. Referring to Figure 13, the base station prioritizes the 1-bit fallback indicator over the M-bit HARQ-ACK to determine whether fallback mode is required. If fallback mode is required, the terminal transmits the fallback indicator to indicate "fallback mode request"; otherwise, the terminal transmits the fallback indicator to indicate "no-fallback request". The base station checks what state the received fallback indicator indicates. If the fallback indicator indicates "fallback mode request", the base station ignores the ACK / NACK / DTX information of the M-bit HARQ-ACK and performs fallback mode. In other words, the base station bundles all CBGs of the relevant TB and retransmits them via the PDSCH. If the fallback indicator indicates "no-fallback request", the base station retransmits the CBGs according to the information of the M-bit HARQ-ACK. In other words, the base station bundles the CBGs (etc.) that have received a NACK response and retransmits them via the PDSCH.

[0122] According to a second embodiment of the present invention, the terminal uses the remaining (NM) bits (etc.) obtained by subtracting M HARQ-ACK bits (etc.) from the N bits secured via the HARQ-ACK resource as a fallback indicator. In this case, priority is given to the (NM)-bit fallback indicator over the M-bit HARQ-ACK, and the feasibility of performing the fallback mode is determined. The terminal transmits N bits, which are the ACK / NACK bits for each of the M CBGs bundled with the (NM)-bit fallback indicator, via the HARQ-ACK resource. In other words, the terminal bundles the (NM)-bit fallback indicator together with the M-bit HARQ-ACK using the HARQ-ACK resource and transmits the N-bit feedback. The base station receives the N-bit feedback via 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 either a "fallback mode request" or a "non-fallback request" state. Because the (MN)-bit fallback indicator consists of multiple bits, it can provide a higher level of transmission reliability than a 1-bit fallback indicator.

[0123] Referring to Figure 13, the method for interpreting the received HARQ-ACK feedback and fallback indicator is as follows: The base station prioritizes the (NM)-bit fallback indicator over the M-bit HARQ-ACK and determines whether fallback mode is required. If fallback mode is required, the terminal transmits the (NM)-bit fallback indicator to indicate "fallback mode request"; otherwise, the terminal transmits the (NM)-bit fallback indicator to indicate "no-fallback request". The base station checks what state the received fallback indicator indicates. If the fallback indicator indicates "fallback mode request", the base station performs fallback mode. If the fallback indicator indicates "no-fallback request", the base station retransmits the CBG according to the information in the M-bit HARQ-ACK. A specific implementation of this is as described in the first embodiment above.

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

[0125] [Table 5]

[0126] Referring to Figure 5, the base station prioritizes checking the fallback indicator over the HARQ-ACK bit. If the fallback indicator indicates a "fallback mode request," the base station always enters fallback mode. That is, the base station retransmits all CBGs constituting the relevant TB, i.e., the first CBG, the second CBG, and the third CBG, to the PDSCH. If the fallback indicator indicates a "non-fallback request," the base station retransmits the CBGs according to the 2-bit HARQ-ACK information. That is, if the terminal's HARQ-ACK is [ACK ACK], the base station determines that the terminal successfully received both CBGs. If the terminal's HARQ-ACK is [ACK NACK], the base station determines that the terminal successfully received the first CBG but 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 successfully received the second CBG but 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 failed to receive both the first and second CBGs. Therefore, the base station bundles the first and second CBGs together and retransmits them via the PDSCH.

[0127] According to a third embodiment of the present invention, the terminal transmits an M+1 bit, which is a bundle of ACK / NACK bits and a 1-bit fallback indicator for each of the M CBGs, via the PUCCH resource. At this time, priority (or equivalent priority) is assigned from the 1-bit fallback indicator to the M-bit HARQ-ACK, and the feasibility of performing the fallback mode is determined. An 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 as described in the first embodiment.

[0128] Figure 14 shows another example of how the received HARQ-ACK feedback and fallback indicator are interpreted. Referring to Figure 14, the base station gives priority (or equivalent priority) to the M-bit HARQ-ACK over the 1-bit fallback indicator to determine whether fallback mode is required. In other words, if all M-bit HARQ-ACKs are NACKs, the base station checks the 1-bit fallback indicator to determine whether fallback mode is required. If fallback mode is required, the terminal transmits so that all M-bit HARQ-ACKs are NACKs and the fallback indicator indicates "request for fallback mode". In this case, the base station bundles all CBGs of the relevant TB and retransmits them via the PDSCH. Otherwise, the base station determines that fallback mode is not required. In other words, if there is at least one ACK among the M-bit HARQ-ACKs, the base station will not perform fallback mode regardless of the value indicated by the feedback indicator. In this case, the base station bundles the CBGs (etc.) that have responded with a NACK in response to the M-bit HARQ-ACK information and retransmits them via the PDSCH.

[0129] According to a fourth embodiment of the present invention, the terminal uses the remaining (NM) bits (etc.) obtained by subtracting M HARQ-ACK bits (etc.) from the N bits secured via the HARQ-ACK resource as a fallback indicator. In this case, priority (or equivalent priority) is given to the M-bit HARQ-ACK from the (NM)-bit fallback indicator, and the feasibility of performing the fallback mode is determined. An embodiment in which the terminal transmits the (NM)-bit fallback indicator together with the M-bit HARQ-ACK via the HARQ-ACK resource and the base station receives it is as described in the second embodiment.

[0130] Referring to Figure 14, the method for interpreting the received HARQ-ACK feedback and fallback indicator is as follows: The base station assigns priority (or equivalent priority) to the M-bit HARQ-ACK based on the (NM)-bit fallback indicator and determines whether fallback mode is required. In other words, if all M-bit HARQ-ACKs are NACKs, the base station checks the (NM)-bit fallback indicator to determine whether fallback mode is required. If fallback mode is required, the terminal transmits so that all M-bit HARQ-ACKs are NACKs and the (NM)-bit fallback indicator indicates "request for fallback mode". In this case, the base station bundles all CBGs of the relevant TB and retransmits them via the PDSCH. Otherwise, the base station determines that fallback mode is not required. In other words, if there is at least one ACK among the M-bit HARQ-ACKs, the base station will not perform fallback mode regardless of the value indicated by the feedback indicator. In this case, the base station bundles the CBGs (etc.) that have responded with a NACK in response to the M-bit HARQ-ACK information and retransmits them via the PDSCH.

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

[0132] [Table 6]

[0133] Referring to Table 6, if the 2-bit HARQ-ACK is [NACK NACK] and the fallback indicator indicates "request for fallback mode," the base station will enter fallback mode. In other words, the base station will retransmit all CBGs constituting the relevant TB, i.e., the first CBG, the second CBG, and the third CBG, to the PDSCH. Otherwise, the base station will determine that fallback mode is not necessary. In this case, the base station will retransmit the CBGs according to the 2-bit HARQ-ACK information. That is, if the terminal's HARQ-ACK is [ACK ACK], regardless of the value of the fallback indicator, the base station will determine that the terminal has successfully received both CBGs. If the terminal's HARQ-ACK is [ACK NACK], regardless of the value of the fallback indicator, the base station will determine that the terminal has successfully received the first CBG but failed to receive the second CBG. Therefore, the base station will retransmit the second CBG via the PDSCH. If the terminal's HARQ-ACK is [NACK ACK], regardless of the fallback indicator value, the base station determines that the terminal successfully received the second CBG but 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] and the fallback indicator indicates "non-fallback request", the base station determines that the terminal failed to receive both the first and second CBGs. Therefore, the base station bundles the first and second CBGs together and retransmits them via the PDSCH.

[0134] According to a fifth embodiment of the present invention, TB retransmission is performed via higher-level retransmission without an explicit fallback indicator. In other words, no feedback mode is used to recover erroneous transmissions at the physical layer. According to one embodiment, the base station and terminal have no explicit fallback indicator resources, only HARQ-ACK resources for CBGs. In this case, if the PDSCH transmission does not contain any CBGs that the terminal needs to retransmit, the terminal transmits an ACK as a HARQ-ACK to all CBGs of the PDSCH transmission, regardless of the success or failure of the CB-CRC and TB-CRC of the PDSCH transmission. In this way, the terminal recognizes the failure to receive the TB but prevents further unnecessary retransmission by transmitting an ACK to all CBGs. The TB that failed to receive is recovered via higher-level retransmission, not via physical-level HARQ-ACK transmission.

[0135] Figure 15 shows an example of how a terminal transmits a HARQ-ACK and fallback indicator to CBGs(et) according to the embodiment described above. According to the embodiment in Figure 15, the base station configures three CBGs on one TB (i.e., N=3), thereby allocating a PUCCH resource to the terminal to transmit 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 out of 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, which has already received an ACK from the terminal. 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 the retransmitted CBG#1 and CBG#2 have been received, and the last bit corresponding to CBG#3 is used as a fallback indicator.

[0136] Figures 16 to 19 show an additional embodiment in which a terminal transmits HARQ-ACK feedback and fallback indicators to CBGs. According to this additional embodiment of the present invention, the length of the HARQ-ACK payload transmitted by the terminal is determined based on the maximum number of CBGs consisting of RRC signals. Thus, the terminal is configured with N CBG-based HARQ-ACK bits. In the embodiments shown in Figures 16 to 19 below, 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 (i.e., M-bit CBG-based HARQ-ACKs) indicating whether each CBG was successfully received. If M is less than N, the remaining NM bits of the N-bit HARQ-ACK are fallback indicators.

[0137] In embodiments of the present invention, the HARQ-ACK indicating whether or not the terminal has successfully received each CBG transmitted via the PDSCH is referred to as the CBG-based HARQ-ACK or the CBG-level HARQ-ACK. Also, as described above, in embodiments of the present invention, the fallback indicator is also referred to as the TB-based HARQ-ACK. In embodiments of the present invention, the HARQ-ACK indicating whether or not the terminal has successfully received each TB transmitted via the PDSCH is referred to as the TB-based HARQ-ACK or the TB-level HARQ-ACK.

[0138] According to embodiments of the present invention, the (NM)-bit fallback indicator can be configured in various ways. In one embodiment, the (NM)-bit fallback indicator consists of either ACK or NACK. In another embodiment, the (NM)-bit fallback indicator consists of 1-bit TB-based HARQ-ACK repeated with NM bits. In yet another embodiment, the (NM)-bit fallback indicator is configured based on the value of M-bit CBG-based HARQ-ACK. If M is a divisor of N, the (NM)-bit fallback indicator consists of a repeated value of M-bit CBG-based HARQ-ACK.

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

[0140] [Table 7]

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

[0142] For example, a terminal is configured in a transmission mode that transmits up to two TBs, and one TB may consist of up to four CBGs. If only one TB is scheduled for the terminal, the CBG-based HARQ-ACKs[b0 b1 b2 b3] for the four CBGs contained in that 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 for the terminal, the CBG-based HARQ-ACKs[b0 b1 b2 b3] for the four CBGs contained in the first TB and the HARQ-ACKs[c0 c1 c2 c3] for the four CBGs contained 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-ACKs thus configured to the base station.

[0143] On the other hand, even in a transmission mode where two TBs are transmitted from one PDSCH, the number of CBGs M included in the TB transmitted by the base station is less than the maximum number of CBGs consisting of RRC signals, which is N. In this case, the method for constructing the remaining NM bits (and so forth) after removing M bits (and so forth) from the N-bit HARQ-ACK is as described in the embodiment above.

[0144] On the one hand, according to an additional embodiment of the present invention, the CBG-based HARQ-ACK(s) for CBG(s) and the 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 the CBG-based HARQ-ACK(s) and the 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 the CBG-based HARQ-ACK(s) and the transmission of the 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 the CBG-based HARQ-ACK(s) and the transmission of the fallback indicator (or TB-based HARQ-ACK). According to an embodiment of the present invention, the resources for transmitting the fallback indicator (or TB-based HARQ-ACK) are configured to be earlier than the resources for transmitting the 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 above resources, resource A in slot n + k1 is the resource for transmitting the fallback indicator (or TB-based HARQ-ACK), and resource B in slot n + k2 is the resource for transmitting the 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] Figure 17 shows an embodiment in which CBG-based HARQ-ACKs and fallback indicators (or TB-based HARQ-ACKs) are transmitted via different HARQ-ACK resources. According to the embodiment in Figure 17, the terminal selectively transmits only one of either CBG-based HARQ-ACKs or TB-based HARQ-ACKs. More specifically, in a situation where a terminal consisting of CBG-based communication transmits a HARQ-ACK to a base station, if all HARQ-ACKs to CBGs are either ACKs or NACKs, the terminal transmits only TB-based HARQ-ACKs and does not transmit CBG-based HARQ-ACKs. On the other hand, if the HARQ-ACKs to CBGs include at least one ACK and at least one NACK, the terminal transmits only CBG-based HARQ-ACKs and does not transmit TB-based HARQ-ACKs.

[0147] The terminal selects one of two different HARQ-ACK resources, depending on the type of HARQ-ACK to be transmitted, from among CBG-based HARQ-ACKs and fallback indicators (i.e., TB-based HARQ-ACKs), and transmits the corresponding HARQ-ACK through the selected resource. As shown in Figure 17(a), when attempting to transmit a TB-based HARQ-ACK, the terminal transmits the TB-based HARQ-ACK via slot n+k1. In this case, the terminal does not transmit CBG-based HARQ-ACKs via slot n+k2. According to one embodiment, if the TB-CRC check is successful, the terminal transmits an ACK as a TB-based HARQ-ACK. On the other hand, if the terminal successfully checks both CB-CRCs but a TB-CRC error occurs, it transmits a NACK as a TB-based HARQ-ACK. Furthermore, if the terminal fails to receive all CBGs (i.e., if all CB-CRCs fail), it transmits a NACK as a TB-based HARQ-ACK. As shown in Figure 17(b), when attempting to transmit a CBG-based HARQ-ACK, the terminal transmits it 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 shown in Figure 17, the operation of the base station is as follows: The base station expects the terminal to transmit a TB-based HARQ-ACK via resource A in slot n+k1. If the base station successfully receives the terminal's TB-based HARQ-ACK via resource A and the HARQ-ACK is an ACK, the base station determines that the terminal has successfully received the TB. If the base station successfully receives the terminal's TB-based HARQ-ACK via resource A and the HARQ-ACK is a NACK, the base station determines that the terminal has failed to receive all CBGs (or all CBs). Therefore, the base station retransmits all CBGs (or all CBs). If the base station successfully receives the terminal's TB-based HARQ-ACK via resource A, it determines that the terminal will not use resource B (i.e., slot n+k2). Therefore, if the terminal's TB-based HARQ-ACK is transmitted via resource A, resource B is used for other purposes. For example, resource B may be used to transmit HARQ-ACKs for other users. On the other hand, if the base station fails to receive the terminal's TB-based HARQ-ACK via resource A, it determines that the terminal has transmitted a CBG-based HARQ-ACK(etc.). Therefore, the base station receives the terminal's CBG-based HARQ-ACK(etc.) via resource B in slot n+k2. Based on the CBG-based HARQ-ACK(etc.), the base station retransmits the CBG(etc.) that the terminal failed to receive.

[0149] Figure 18 shows another embodiment in which CBG-based HARQ-ACKs and fallback indicators (or TB-based HARQ-ACKs) are transmitted via different HARQ-ACK resources. According to the embodiment in Figure 18, the terminal transmits either only TB-based HARQ-ACKs or both CBG-based HARQ-ACKs and TB-based HARQ-ACKs, depending on whether it has successfully received all CBGs.

[0150] As shown in Figure 18(a), if the terminal successfully receives all CBGs and the TB-CRC check is successful, the terminal transmits an ACK as a TB-based HARQ-ACK via slot n+k1. In this case, the terminal does not transmit a CBG-based HARQ-ACK (etc.) via slot n+k2. As shown in Figure 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 via slot n+k1. In this case, the terminal transmits a CBG-based HARQ-ACK (etc.) via slot n+k2.

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

[0152] According to another embodiment of the present invention, even when the TB-based HARQ-ACK is ACK, the terminal's TB-based HARQ-ACK and CBG-based HARQ-ACK(s) are both transmitted. The base station receives the TB-based HARQ-ACK and CBG-based HARQ-ACK(s) via Resource A and Resource B respectively, and determines whether the terminal has successfully received based on the received HARQ-ACK. For example, if the TB-based HARQ-ACK is ACK and all of the CBG-based HARQ-ACK(s) are 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). As another method, 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 base station fails to receive the CBG-based HARQ-ACK(s) via Resource B even though the TB-based HARQ-ACK is NACK, the base station determines that the terminal has failed to receive all of the CBGs and retransmits all of the CBGs. According to another embodiment, if the base station fails to receive the CBG-based HARQ-ACK(s) via Resource B even though the TB-based HARQ-ACK is NACK, the base station regards that an ACK-to-NACK error has occurred in the TB-based HARQ-ACK and determines that the terminal has successfully received the corresponding TB.

[0154] Also, if the TB-based HARQ-ACK is NACK and all of the CBG-based HARQ-ACK(s) are ACK, the base station assumes that the terminal has failed to receive all of the CBGs and retransmits all of the CBGs. According to yet another embodiment, if the TB-based HARQ-ACK is NACK and all of the CBG-based HARQ-ACK(s) are ACK, the base station regards that an ACK-to-NACK error has occurred in the TB-based HARQ-ACK and determines that the terminal 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 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. Thus, 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 obtains the values of offset k1 and offset k2 by using the value of the difference between one of the offsets instructed via DIC and the offset that is known in advance (or fixed) to the terminal. 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 terminal, in the above embodiment, the TB-based HARQ-ACK transmitted via resource A in 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(etc.) transmitted via resource B in slot n+k2 is a multiplexed CBG-based HARQ-ACK for one or more TBs. According to one embodiment, the CBG-based HARQ-ACK(etc.) transmitted via resource B is generated by multiplexing the CBG-based HARQ-ACK bits for TBs to which a NACK has been transmitted as a TB-based HARQ-ACK. In other words, for TBs to which an ACK has been transmitted as a TB-based HARQ-ACK transmitted via resource A, CBG-based HARQ-ACK transmission is not performed via resource B.

[0158] On the other hand, in the above-described embodiment, resources were explained based on slot units, but the present invention is not limited to this. That is, in situations such as Short-PUCCH transmission, the slots in the above-described embodiment are switched to OFDM symbols. In this case, OFDM symbols n+k1 and / or OFDM symbols n+k2 are OFDM symbols in which PUCCH begins.

[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 resources 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 resources B configured in the same slot n + k for 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, the terminal that uses the compressed CBG-based HARQ-ACK with the payload length reduced 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] The first embodiment for generating a compressed CBG-based HARQ-ACK is as follows: The base station selects a state from the total CBG-based HARQ-ACK states for a single TB that is expected to occur frequently, and has the terminal signal this state. Here, the CBG-based HARQ-ACK state refers to the combination of bits that the original CBG-based HARQ-ACK can have. In other words, a 4-bit CBG-based HARQ-ACK has a total of 16 states, i.e., [ACK ACK ACK ACK] to [NACK NACK NACK NACK]. The base station selects P states from the original CBG-based HARQ-ACK states as described above. In other words, if the total number of TBs transmitted via PDSCH is I, then the CBG-based HARQ-ACK state under the i-th TB is P i It is mapped to the second state. In this case, the terminal is mapped to the P for all I TBs. i U is obtained by multiplexing via the following formula, and the U is converted to binary to obtain the compressed CBG-based HARQ-ACK(e) for the entire TB(e).

[0162]

number

[0163] The base station receives compressed CBG-based HARQ-ACK(ar) from the terminal, converts the compressed CBG-based HARQ-ACK(ar) to base P, and maps the CBG-based HARQ-ACK state information P to each TB. i To obtain.

[0164] In one embodiment, the value of P and information on P CBG-based HARQ-ACK states selected by the base station are configured via an RRC signal transmitted by the base station to the terminal. In another embodiment, the value of P is determined based on at least one of the following: the capacity of PUCCH that the terminal can transmit, and the number of TB (or PDSCH) that the terminal should transmit. Furthermore, in order to determine the P CBG-based HARQ-ACK states, the entire set of CBG-based HARQ-ACK states is pre-arranged in a predetermined order. In one embodiment, the pre-arranged order is determined based on the frequency of occurrence of each state among the entire set of CBG-based HARQ-ACK states. For example, a CBG-based HARQ-ACK state indicating a reception error of an adjacent CBG is determined in a higher order than a CBG-based HARQ-ACK state indicating a reception error of a non-adjacent CBG. P states among the entire set of CBG-based HARQ-ACK states are selected based on this pre-arranged order.

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

[0166] [Table 8]

[0167] Each of the selected P states is based on a pre-arranged order. i It is indexed to the nth state. As mentioned above, each TB is the original CBG-based HARQ-ACK state, of which p states are p i It is mapped to the nth state. If N is the number of original CBG-substrate HARQ-ACK states, then an N-to-P mapping is performed. According to an embodiment of the present invention, the original CBG-substrate HARQ-ACK state is mapped to p based on the NACK bit of the original state.i is mapped to the n-th state. That is, in the original CBG-based HARQ-ACK state, the NACK bit is the p i th CBG-based HARQ-ACK state should also be NACK. For example, in the original CBG-based HARQ-ACK state, if the second bit is NACK (i.e., 0), the states to which the original state can be mapped are the states where the second bit is NACK, that is, any one of

[0000] ,

[0001] ,

[0010] ,

[0011] ,

[1000] ,

[1001] ,

[1010] , and

[1011] .

[0168] The second embodiment of generating the compressed CBG-based HARQ-ACK is as follows. Let the maximum number of CBGs consisting of RRC signals be N, and the number of CBG(s) included in the TB transmitted by the base station be M. At this time, M bits (or bits) among the N-bit HARQ-ACK are CBG-based HARQ-ACKs indicating whether each CBG is 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. That is, the original CBG-based HARQ-ACK for one TB consists of N bits. At this time, the original CBG-based HARQ-ACK is represented by [b0, b1,..., b M-1 , X0, X1,..., X N-M-1 . That is, the original CBG-based HARQ-ACK consists of the M-bit CBG-based HARQ-ACK [b0, b1,..., b M-1 and the remaining N - M bits (or bits) [X0, X1,..., X N-M-1 . At this time, Xm consists of a fixed value (for example, ACK or NACK) or is configured based on the value of the M-bit CBG-based HARQ-ACK. The specific method for this is as in the above-described embodiment.

[0169] To reduce the length of the HARQ-ACK payload, the base station instructs the terminal to use the compressed CBG-based HARQ-ACK. The base station signals the indication information via an RRC signal or PDCCH. If the terminal receives the information indicating the use of the compressed CBG-based HARQ-ACK, the terminal reduces the original CBG-based HARQ-ACK consisting of N bits to the 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 represented by [b0, b1, …, b M-1 , Y0, Y1, …, Y L-M-1 . That is, the compressed CBG-based HARQ-ACK consists of the M-bit CBG-based HARQ-ACK [b0, b1, …, b M-1 and the remaining L - M bits (or [Y1, …, Y L-M-1 ). Therefore, the M-bit CBG-based HARQ-ACK is included in the compressed CBG-based HARQ-ACK as it is, and only the remaining bits (or) are reduced from N - M to L - M. That is, the M-bit CBG-based HARQ-ACK is saved in the compressed CBG-based HARQ-ACK. At this time, Y m consists of a fixed value (for example, ACK or NACK) or is configured based on the value of the M-bit CBG-based HARQ-ACK.

[0171] If L is less than M, the compressed CBG-based HARQ-ACK consists of [a0, a1, …, a M-1 . At this time, the compressed CBG-based HARQ-ACK is generated by combining at least a part of the M-bit CBG-based HARQ-ACK [b0, b1, …, b M-1 excluding the remaining N - M bits (or) from the original CBG-based HARQ-ACK. According to one embodiment, in the compressed CBG-based HARQ-ACK [a0, a1, …, a M-1 , for k = 0 to L - 2, a k is b 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), and otherwise it is 0 (i.e., NACK). Also, a = L-1 k is b k*w , b k*w+1 , ..., b M-1 If both are 1 (i.e., ACK), then it is 1 (i.e., ACK), and otherwise it is 0 (i.e., NACK). Here, v = floor(M / L).

[0172] For example, let's assume N=8 and M=4, and that the remaining NM bits (i.e., 4 bits) always transmit 0 (i.e., NACK). Let's also assume the original CBG-based HARQ-ACK is [10110000]. If we generate a 4-bit compressed CBG-based HARQ-ACK from the original CBG-based HARQ-ACK, the compressed CBG-based HARQ-ACK will be

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

[1011] is preserved in the compressed CBG-based HARQ-ACK even when the payload length is reduced to 4 bits. On the other hand, if we generate a 2-bit compressed CBG-based HARQ-ACK from the original CBG-based HARQ-ACK, the compressed CBG-based HARQ-ACK will be

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

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

[01] is generated by bundling 4-bit CBG-base HARQ-ACK

[1011] in 2-bit chunks.

[0173] In the following embodiments, it is assumed that the transmission information is in component carrier units. In one embodiment of the present invention, the component carrier is switched to the term cell. In the embodiments of the present invention, for the sake of 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 HARQ-ACK is multiplexed. The terminal receives PDSCH(s) from one or more component carrier(s) and generates a HARQ-ACK bit sequence as a response thereto. The HARQ-ACK bit sequence is generated by combining the HARQ-ACK bit(s) for each component carrier of one or more component carrier(s). In the embodiments of the present invention, it is switched to terms such as HARQ-ACK information bit(s), HARQ-ACK codebook, HARQ-ACK codeword, HARQ-ACK payload, etc. Also, in the following embodiments, the HARQ-ACK bit sequence for TB-based transmission (or PDSCH) is referred to as the TB-based HARQ-ACK bit sequence, and the HARQ-ACK bit sequence for CBG-based transmission (or PDSCH) is referred to as the CBG-based HARQ-ACK bit sequence, respectively.

[0174] If carrier aggregation is used, each component carrier consists of a different transmission method. That is, the first component carrier consists of one TB transmission, and the second component carrier consists of two TB transmissions. Moreover, in the 3GPP NR system, as described above, CBG-based transmission is supported together with TB-based transmission. That is, the first component carrier consists of TB-based transmission, and the second component carrier consists of CBG-based transmission.

[0175] On the other hand, the terminal monitors the PDCCH on a specific component carrier according to the method configured for the terminal, either self-carrier scheduling or cross-carrier scheduling, and receives the PDSCH based on the information from the PDCCH. The terminal also 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 for some of the component carriers configured by the base station (i.e., a DTX occurs). In this case, the terminal excludes the HARQ-ACK(etc.) from the affected component carrier and transmits only the HARQ-ACK(etc.) from the component carrier that was successfully decoded to the PUCCH (or PUSCH). However, if the terminal excludes the transmission of HARQ-ACK(etc.) from some component carriers, there is a risk of errors occurring in the interpretation of the HARQ-ACK feedback between the base station and the terminal. To solve this problem, LTE-A Rel.13 uses a method that detects DTX using the DAI.

[0176] Figure 20 shows an example of DAI values ​​mapped to each component carrier. Referring to Figure 20, each PDCCH scheduling a PDSCH includes a counter-DAI and a total-DAI. The counter-DAI indicates the cumulative number of scheduled PDSCHs from the first component carrier (i.e., component carrier #0) to the current component carrier. The total-DAI indicates the total number of scheduled PDSCHs for the entire component carrier. If the counter-DAI field consists of A bits, then the counter-DAI is between 0 and 2. A It has n-1 values ​​(where n is a natural number). If C is the number of PDSCH(etc.) scheduled from the first component carrier to the current component carrier, then the value of counter-DAI is (C-1)mod2. AThis is how it is set. Similarly, if the total-DAI field consists of B bits, then the total-DAI is 0 to 2 B It has m-1 values ​​(where m is a natural number). If T is the total number of PDSCH(etc.) scheduled on the component carrier, then the total value of -DAI is (T-1)mod2 B This is how it is set. The terminal decodes the PDCCH to identify the order in which the PDSCH was transmitted under the schedule. At this time, the terminal transmits the HARQ-ACK of the PDSCH according to the order in which the PDSCH was transmitted.

[0177] Referring to Figure 20, the base station transmits PDSCHs via component carriers #0, #1, #3, #4, #5, and #7 to a terminal that can use up to eight component carriers in a merged configuration. Since the total number of PDSCHs scheduled on the component carriers is 6, the total-DAI value is set to 5. Therefore, the (counter-DAI, total-DAI) values ​​for 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 a PDCCH transmitted via component carrier #3 fails, the terminal identifies that it failed to receive one PUCCH (and the corresponding one PDSCH) based on the counter-DAI values ​​of the PDCCH transmitted via component carrier #1 and the PDCCH transmitted via component carrier #4. Furthermore, if decoding of a 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 one PDCCH was scheduled after component carrier #5 but was not successfully received.

[0178] As described above, using DAI, the terminal can identify the order in which PDSCHs were successfully received and the order in which they were not. However, since the terminal does not know the number of TBs contained in the PDSCHs that were not received, it cannot determine the HARQ-ACK bit sequence. Two methods are used to solve this. The first method is to apply spatial bundling to all PDSCHs. In other words, the 2-bit HARQ-ACK for PDSCHs that transmit 2 TBs is bundled into 1 bit. This method does not have additional UCI overbed, but it may reduce transmittance. The second method is to not apply spatial bundling and assume that each PDSCH contains 2 TBs. In other words, this method transmits a 2-bit HARQ-ACK even for PDSCHs that transmit 1 TB. This method has the disadvantage of generating additional UCI overbed.

[0179] On the other hand, as mentioned above, the 3GPP NR system supports both TB-based transmission and CBG-based transmission. If a terminal is configured to multiplex and transmit HARQ-ACK bits to multiple component carriers, the base station will inform the terminal whether CBG-based transmission is possible for each component carrier. However, TB-based transmission may also occur for component carriers that constitute CBG-based transmission. Therefore, the terminal may expect only TB-based transmission for a particular component carrier, and both TB-based and CBG-based transmission for other specific component carriers. The terminal cannot determine the HARQ-ACK bit sequence to transmit on the uplink until it has received successful PDCCHs scheduled for each component carrier.

[0180] According to one embodiment of the present invention, the above-described DAI is used to prevent errors in determining and interpreting the HARQ-ACK bit sequence between the base station and the terminal. Assuming that N HARQ-ACK bits are required as a response to the CBG-underground transmission, the terminal and 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, it is assumed that if a base station configures CBG-based transmission with at least one component carrier along with carrier aggregation to a terminal, then CBG-based transmission will be performed for all PDSCHs scheduled to the terminal. In other words, even if the base station performs TB-based transmission to the terminal from a specific component carrier, the terminal will feed back an N-bit HARQ-ACK, where N is the maximum number of CBGs per TB configured in the terminal. However, the first method has the disadvantage of excessively large PUCCH overhead. For example, if N=4, the 1-bit HARQ-ACK increases to 4 bits, which can result in an overhead of up to 300%.

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

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

[0184] As described above, if a terminal using HARQ-ACK multiplexing is configured with both TB-based transmission and CBG-based transmission, a signaling scheme is provided to prevent interpretation errors of the HARQ-ACK bit sequence between the base station and the terminal. According to one embodiment of the present invention, the terminal receives a PDCCH from one or more component carriers(s) instructing each component carrier's PDSCH scheduling information. The terminal also receives a DCI via the PDCCH. In this case, at least one of the one or more component carriers(s) is configured with CBG-based transmission. In addition, at least one TB-based transmission and at least one CBG-based transmission are configured. The terminal identifies the transmission method in each component carrier based on the DCI format of the DCI. In this case, the transmission method is either TB-based transmission or CBG-based transmission. Meanwhile, the terminal receives a DAI via the 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 as a response to the reception of the PDSCH of each component carrier. In this process, the terminal generates the HARQ-ACK bit sequence by referring to the DAI. The HARQ-ACK bit sequence includes at least one of the following: a HARQ-ACK bit sequence for TB-based transmission (i.e., a TB-based HARQ-ACK bit sequence) and a HARQ-ACK bit sequence for CBG-based transmission (i.e., a CBG-based HARQ-ACK bit sequence). According to embodiments of the present invention, the DAI is applied separately to the TB-based HARQ-ACK bit sequence and the CBG-based HARQ-ACK bit sequence, respectively. Furthermore, within the HARQ-ACK bit sequence, the TB-based HARQ-ACK bit sequence is located before the CBG-based HARQ-ACK bit sequence.

[0186] The terminal generates a HARQ-ACK bit sequence for one or more cells based on the identified transmission method of each cell. That is, within the HARQ-ACK bit sequence, a TB-based HARQ-ACK bit sequence and a CBG-based HARQ-ACK bit sequence are generated, respectively. In this case, the TB-based HARQ-ACK bit sequence generates one HARQ-ACK bit per TB, and the CBG-based HARQ-ACK bit sequence generates N HARQ-ACK bits per TB. In other words, the HARQ-ACK bits for the CBG-based PDSCH are configured to have N bits per TB, regardless of the number of CBGs that are actually scheduled and transmitted to the PDSCH.

[0187] According to one 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, in one or more component carriers, if the number M of CBGs transmitted via a specific component carrier on which CBG-underlying transmission is configured is less than N, the HARQ-ACK bits for the specific component carrier are composed of repeated HARQ-ACK bits for the transmitted CBGs. Also, in one or more component carriers, if the number M of CBGs transmitted via a specific component carrier on which CBG-underlying transmission is configured is less than N, the HARQ-ACK bits for the specific component carrier consist of M HARQ-ACK bits and NM NACKs for the transmitted CBGs. The terminal transmits the generated HARQ-ACK bit sequence in this manner to the base station.

[0188] When a terminal receives a PDCCH, it identifies whether the PDSCH scheduling the PDSCH applies TB-based transmission or CBG-based transmission. Based on the DCI information received via the PDCCH, the terminal identifies the transmission scheme for each component carrier (i.e., the PDSCH). For example, the transmission scheme information is signaled in an explicit 1-bit in the DCI, or inferred through a combination of other information contained in the DCI. The transmission scheme for each component carrier is also identified based on the DCI format of the DCI. Different transmission schemes use different DCI formats. Different DCI formats have different amounts of information contained in the DCI; that is, different DCI formats have different DCI payload lengths. Also, different DCI formats scramble the CRC with different RNTIs. Furthermore, when a PDCCH scheduling a CBG-based PDSCH is received, the terminal identifies, through the information explicitly contained in the DCI, which CCBs (etc.) of the overall CBG the PDSCH consists of.

[0189] The following describes specific embodiments for generating a HARQ-ACK bit sequence as a response to PDSCH reception, with reference to the respective drawings. In each embodiment, it is assumed that at least one component carrier (i.e., cell) from one or more component carriers (etc.) configured by the base station has a CBG-underlying transmission configured. For example, one or more component carriers (etc.) have at least one TB-underlying transmission and at least one CBG-underlying transmission configured. In the embodiments of each drawing, redundant explanations are omitted for parts that are the same as or corresponding to embodiments of previous drawings. In embodiments of the present invention, for the sake of narrative convenience, it is assumed that the values ​​of each index or counter increase from 0 to 1. However, embodiments of the present invention are not limited to this, and the values ​​of the index or counter may increase from a preset value (e.g., 1) to 1.

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

[0191] [Table 9]

[0192] Referring to Table 9, the counter-DAI field and total-DAI field of the scheduling PDCCH for TB-based PDSCH represent the counter-DAI and total-DAI for TB-based transmission, respectively. Similarly, the counter-DAI and total-DAI of the scheduling PDCCH for CBG-based PDSCH represent the counter-DAI and total-DAI for CBG-based transmission, respectively.

[0193] First, the counter-DAI for TB-based transmission indicates the cumulative number of TB-based PDSCHs 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, then the cumulative number of TB-based PDSCHs scheduled up to the previous component carrier is C. Similarly, the counter-DAI for TB-based transmission indicates the cumulative number of TB-based PDSCHs 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, then the cumulative number of TB-based PDSCHs scheduled up to the current component carrier is C+1. Furthermore, the total-DAI for TB-based transmission indicates the total number of TB-based PDSCHs scheduled across all component carriers. If the value of the total-DAI is T, then the total number of TB-based PDSCHs scheduled across all component carriers is T+1.

[0194] Next, the counter-DAI for CBG-based transmission indicates the cumulative number of CBG-based PDSCHs (etc.) 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, then the cumulative number of CBG-based PDSCHs (etc.) scheduled up 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 PDSCHs (etc.) 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, then the cumulative number of CBG-based PDSCHs (etc.) scheduled up to the current component carrier is C+1. Furthermore, the total-DAI for CBG-based transmission indicates the total number of CBG-based PDSCHs scheduled across all component carriers. If the value of the total-DAI is T, then the total number of CBG-based PDSCHs scheduled across all component carriers is T+1.

[0195] Figure 21 is a diagram showing the DAI signaling method according to the first embodiment described above. Referring to Figure 20, PDSCHs are transmitted to the terminal via component carriers #0, #1, #3, #4, #5, and #7. Of these, 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 to 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 (etc.) scheduled up to the current component carrier. Therefore, the values ​​of the (counter-DAI, total-DAI) fields of the PDCCH for component carriers #0, #3, #5, and #7 to which the CBG-based PDSCH is transmitted are (0, 3), (1, 3), (2, 3), and (3, 3), respectively. Similarly, since the total number of TB-based PDSCHs scheduled for the entire component carrier is 2, the value of the total-DAI field for TB-based transmission is set to 1. In addition, 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 PDSCHs (etc.) scheduled up to the current component carrier. Therefore, the values ​​of the (counter-DAI, total-DAI) fields of the PDCCH for component carriers #1 and #4 to which the TB-based PDSCH is transmitted are (0, 1) and (1, 1), respectively.

[0196] The terminal receives a PDCCH that schedules a PDSCH and identifies the transmission method of the PDSCH. For example, the terminal identifies the PDSCH transmission method based on the DCI format of the DCI that received the PDCCH. In this case, the terminal interprets the values ​​of the counter-DAI field and total-DAI field of the received PDCCH as the counter-DAI and total-DAI for the PDSCH transmission method that the PDCCH schedules, respectively. For example, in the embodiment shown in Figure 21, if a PDCCH that schedules a PDSCH transmitted via component carrier #3 is received, the terminal identifies that a CBG-based PDSCH is being transmitted via carrier #3 and interprets the values ​​of the counter-DAI field and total-DAI field of the PDCCH as the counter-DAI and total-DAI for CBG-based transmission, respectively. Since the values ​​of the received (counter-DAI, total-DAI) fields are (1, 3), the terminal identifies that a total of four CBG-based PDSCHs are assigned to the overall component carrier, and 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 in accordance with the increase in the component carrier index (i.e., not in the order of 0 → 1 → 2 → 3…), the terminal determines that it has failed to receive some of the PDCCHs that schedule CBG-based transmission. Furthermore, if the counter-DAI value of the last PDCCH that was successfully received and the total-DAI value are different, the terminal determines that it has failed to receive at least one PDCCH that schedules CBG-based transmission after the last PDCCH. In this case, the number of PDCCHs that schedule CBG-based transmission and have failed to be received after the last PDCCH that was successfully received is identified by the difference between the total-DAI value and the counter-DAI value of the last PDCCH. This method of interpreting counter-DAI values ​​and total-DAI values ​​also applies to the interpretation of counter-DAI values ​​and total-DAI values ​​for TB-based transmission.

[0198] Referring to Figure 21, the terminal fails to decode the PDCCH transmitted via component carriers #3 and #7, which are scheduled for CBG-based transmission, but succeeds in decoding the PDCCH transmitted via the remaining component carriers #0 and #5, which are also scheduled for CBG-based transmission. In this case, the terminal receives counter-DAI values ​​of 0 and 2, respectively, for CBG-based transmission. Therefore, the terminal identifies that it failed to receive the PDCCH with counter-DAI=1 among the PDCCHs that schedule CBG-based transmission. In addition, a total-DAI value of 3 is received for CBG-based transmission, but since the counter-DAI value of the last PDCCH that was successfully received among the PDCCHs that schedule CBG-based transmission is 2, the difference between the total-DAI value and the counter-DAI value of the last PDCCH is 1. Therefore, the terminal identifies that it failed to receive one more PDCCH that schedules CBG-based transmission after the last PDCCH.

[0199] Figure 22 shows a method for generating a HARQ-ACK bit sequence based on the DAI signaled by the first embodiment described above. According to an embodiment of the present invention, the terminal generates a HARQ-ACK bit sequence for the entire component carrier in response to the reception of the PDSCH of each component carrier. In this case, the terminal generates the HARQ-ACK bit sequence based on the 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. The terminal also generates the HARQ-ACK bit sequence by referring to the DAI of the PDCCH that schedules the PDSCH of each component carrier. In this case, the DAI is applied separately to the TB-based HARQ-ACK bit sequence and the CBG-based HARQ-ACK bit sequence, respectively.

[0200] More specifically, the terminal generates a CBG-based HARQ-ACK bit sequence by combining N-bit HARQ-ACKs for each CBG-based transmission in the order of the CBG-based transmission's counter-DAI value. In the CBG-based HARQ-ACK bit sequence, each bit indicates whether a single CBG was successfully received. According to an embodiment of the present invention, the CBG-based HARQ-ACK bit sequence generates N HARQ-ACK bits per TB, where N is the maximum number of CBGs per TB configured in the terminal. The terminal also generates a TB-based HARQ-ACK bit sequence by combining 1 or 2-bit HARQ-ACKs for each TB-based transmission in the order of the TB-based transmission's counter-DAI value. Incidentally, the HARQ-ACK for a TB-based transmission is configured as 1-bit per PDSCH if spatial bundling is applied, and as a maximum of 2-bits per PDSCH if spatial bundling is not applied. In the embodiment shown in Figure 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 PDCCHs that schedule CBG-based transmissions, the CBG-based HARQ-ACK bit sequence is excluded from the HARQ-ACK bit sequence. In other words, the HARQ-ACK bit sequence consists only of the TB-based bit sequence. Similarly, if the terminal does not receive any PDCCHs that schedule TB-based transmissions, the TB-based HARQ-ACK bit sequence is excluded from the HARQ-ACK bit sequence. In other words, the HARQ-ACK bit sequence consists only of the CBG-based bit sequence. The terminal combines the CBG-based HARQ-ACK bit sequence and the TB-based HARQ-ACK bit sequence to form the entire HARQ-ACK bit sequence. According to an embodiment of the present invention, the terminal attaches the CBG-based HARQ-ACK bit sequence after the TB-based HARQ-ACK bit sequence to form the entire HARQ-ACK bit sequence. Referring to Figure 22, the HARQ-ACK bit sequence formed by the terminal is [x0 (0) x1 (0) , ..., x N-1 (0) x0 (1) x1 (1) , ..., x N-1 (1) x0 (2) x1 (2) , ..., x N-1 (2) x0 (3) x1 (3) , ..., x N-1 (3) , y0 (0) , y0 (1) ]. Here, x is the CBG-underlying HARQ-ACK bit, and y is the TB-underlying 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 within the PDSCH.

[0202] On the other hand, according to the first embodiment described above, 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. In other words, the terminal should receive at least one PDCCH scheduling CBG-based transmission and at least one PDCCH scheduling TB-based transmission. If the terminal receives only a PDCCH for one transmission method, scheduling information for other transmission methods will not be identified. For example, if the terminal does not successfully receive one PDCCH scheduling TB-based transmission, the terminal cannot know whether the PDCCH for TB-based transmission is available, and therefore will not generate the TB-based HARQ-ACK bit sequence. In this case, there is a risk of errors occurring in the interpretation of the HARQ-ACK bit sequence between the base station and the terminal, so a method to resolve this is necessary.

[0203] Figure 23 shows a DAI signaling method according to a second embodiment of the present invention. According to the second embodiment of the present invention, the base station transmits a counter-DAI value according to the transmission method of the PDSCH via the counter-DAI value field of the PDCCH that schedules the PDSCH, and transmits either a total-DAI value for TB-underground transmission or a total-DAI value for CBG-underground transmission via the total-DAI field of the PDCCH based on the counter-DAI value. In other words, according to the second embodiment of the present invention, the counter-DAI field signals the counter-DAI value according to the transmission method of the PDSCH, while the total-DAI field selectively signals the total-DAI value according to the transmission method of the PDSCH or the total-DAI value according to the other transmission method, depending on the counter-DAI value. According to one embodiment, if the counter-DAI value is even, the total-DAI field shows the total-DAI value according to the transmission method of the PDSCH; if the counter-DAI value is odd, the total-DAI field shows the total-DAI value according to a transmission method other than the transmission method of the PDSCH.

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

[0205] [Table 10]

[0206] Referring to Table 10, the counter-DAI field of a PDCCH that schedules a TB-based PDSCH indicates the counter-DAI for TB-based transmission, and the counter-DAI field of a PDCCH that schedules a CBG-based PDSCH indicates the counter-DAI for CBG-based transmission. On the other hand, the total-DAI field of a PDCCH that schedules a TB-based PDSCH indicates the total-DAI for TB-based transmission if the value of the counter-DAI field of the PDCCH is even, and indicates the total-DAI for CBG-based transmission if the value of the counter-DAI field of the PDCCH is odd. Similarly, the total-DAI field of a PDCCH that schedules a CBG-based PDSCH indicates the total-DAI for CBG-based transmission if the value of the counter-DAI field of the PDCCH is even, and indicates the total-DAI for TB-based transmission if the value of the counter-DAI field of the PDCCH is odd. On the other hand, the information shown by the counter-DAI and total-DAI for TB-based transmission, and the counter-DAI and total-DAI for CBG-based transmission, is as described in the first embodiment above.

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

[0208] The terminal receives a PDCCH that schedules a PDSCH and identifies the transmission method of the PDSCH. At this time, the terminal interprets the value of the counter-DAI field of the received PDCCH as the counter-DAI for the transmission method of the PDSCH that the PDCCH schedules. Conversely, when the terminal rescales the value of the total-DAI field of the received PDCCH, if the counter-DAI value is even, it is interpreted as the total-DAI for the transmission method of the PDSCH in question, and if the counter-DAI value is odd, it is interpreted as the total-DAI for a transmission method other than the transmission method of the PDSCH in question. For example, in the embodiment shown in Figure 23, if a PDCCH that schedules 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 of the PDCCH as counter-DAI for CBG-based transmission. In this case, since the value of the counter-DAI field is odd, the terminal interprets the value of the total-DAI field of the PDCCH as the total-DAI for TB-based transmission. Since the value of the received (counter-DAI, total-DAI) field is (1, 1), the terminal identifies that the PDSCH transmitted via component carrier #3 is the second CBG-based PDSCH, and that a total of two TB-based PDSCHs are assigned to the component carrier in total.

[0209] The method by which a terminal determines whether it has failed to receive a PDCCH scheduling CBG-based transmission or TB-based transmission based on counter-DAI and / or total-DAI is similar to that of the first embodiment described above. However, in order to obtain the total-DAI for a particular transmission method, the terminal should refer to the total-DAI field of a PDCCH where the counter-DAI field value is even. Therefore, in the first embodiment described above, the total-DAI value of the last PDCCH should be switched to the total-DAI value of a PDCCH where the counter-DAI field value is even. On the other hand, in order to obtain the total-DAI for a particular transmission method, the terminal refers to the total-DAI field of a PDCCH scheduling PDSCHs for other transmission methods where the counter-DAI field value is odd. The terminal then refers to the total-DAI for the transmission method obtained in this way to determine whether it has failed to receive at least some of the PDCCHs.

[0210] On the other hand, according to the second embodiment described above, even if the terminal only receives a PDCCH that schedules a PDSCH for one transmission method, it can still know the number of PDSCHs scheduled for other transmission methods. Therefore, even if the reception of all PDCCHs that schedule PDSCHs for a specific transmission method fails, it is possible to prevent errors in the 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 that PDCCH, the terminal can still identify the number of scheduled TB-based PDSCHs via the PDCCH that schedules CBG-based transmission. However, in a situation where only one PDCCH is successfully received, there is still a risk of errors occurring in the interpretation of the HARQ-ACK bit sequence between the base station and the terminal.

[0211] Figure 24 shows a DAI signaling method according to a third embodiment of the present invention. According to the third embodiment of the present invention, the base station generates independent counter-DAIs for TB-based transmission and CBG-based transmission, respectively, and generates a common total-DAI used for both transmission methods. The base station transmits the counter-DAI value according to the transmission method of the PDSCH via the counter-DAI field of the PDCCH that schedules the PDSCH, and transmits the common total-DAI value via the total-DAI field of all PDCCHs. In other words, according to the third embodiment of the present invention, the counter-DAI field signals the counter-DAI value according to the transmission method of the PDSCH, but the total-DAI field signals only one of the total-DAI values ​​for TB-based transmission and the total-DAI value for CBG-based transmission. The terminal interprets the counter-DAI received via the PDCCH as the counter-DAI for the transmission method of the PDSCH scheduled by the PDCCH. Furthermore, the terminal interprets the total-DAI received via PDCCH as the total-DAI that is common to all transmission schemes. Table 11 shows how the terminal interprets the counter-DAI and total-DAI generated by 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 is as described in the first and second embodiments above. 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 show a common total-DAI. The common total-DAI value is determined by various embodiments. If at least one TB-based PDSCH and at least one CBG-based PDSCH are scheduled on the entire component carrier, the common total-DAI value indicates the total number of PDSCHs of any one transmission scheme scheduled on the entire component carrier. According to one embodiment, the common total-DAI value indicates the total number of CBG-based PDSCHs scheduled on the entire component carrier. 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 transmission method of PDSCH is scheduled in the entire component carrier, the common total-DAI value is determined to a preset value. According to an embodiment of the present invention, if a 2-bit total-DAI is used, the preset value is the binary number "11". If a 3-bit total-DAI is used, the preset value is "011" or "111".

[0214] Figure 24 shows the DAI signaling method according to the third embodiment described above. In the embodiment of Figure 24, the situation in which CBG-based PDSCH and TB-based PDSCH are transmitted via each component carrier is the same as in the first embodiment described above. In one embodiment, if the common total-DAI value indicates the total number of CBG-based PDSCH, then the total-DAI field for CBG-based transmission and the total-DAI field for TB-based transmission are both set to 3. Therefore, the values ​​of the (counter-DAI, total-DAI) fields of the PDCCH for component carriers #0, #3, #5, and #7 to which CBG-based PDSCH is transmitted are (0, 3), (1, 3), (2, 3), and (3, 3), respectively. Also, the values ​​of the (counter-DAI, total-DAI) fields of the PDCCH for component carriers #1 and #4 to which TB-based PDSCH is transmitted are (0, 3) and (1, 3), respectively.

[0215] The terminal receives a PDCCH that schedules a PDSCH and identifies the transmission method of the PDSCH. At this time, the terminal interprets the value of the counter-DAI field of the received PDCCH as the counter-DAI for the transmission method of the PDSCH that the PDCCH schedules. Conversely, the terminal interprets the value of the total-DAI field of the received PDCCH as the total-DAI applicable to both CBG-based transmission and TB-based transmission. For example, in the embodiment shown in Figure 24, if a PDCCH that schedules 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 fields of the PDCCH as the counter-DAI for CBG-based transmission. The terminal also interprets the value of the total-DAI field of the PDCCH as the total-DAI applicable to both CBG-based transmission and TB-based transmission. Since the value of the received (counter-DAI, total-DAI) field is (1, 3), the terminal identifies that the PDSCH transmitted via component carrier #3 is the second CBG-based PDSCH, and that four CBG-based PDSCHs and four TB-based PDSCHs are allocated to the entire component carrier. On the other hand, 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 number of scheduled CBG-based PDSCHs and TB-based PDSCHs may not be the same. That is, if the total-DAI field consists of B bits and signals a common total-DAI value k, then 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 2 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 by which the terminal determines, based on the counter-DAI and / or total-DAI, that it has failed to receive a PDCCH that schedules CBG-based transmission or TB-based transmission is similar to that of the first embodiment described above. However, if the received common total-DAI indicates a preset value and no PDCCHs that schedule a PDSCH of a specific transmission method are received at all, the terminal determines that the PDSCH of the specific transmission method is not scheduled. When the terminal generates a HARQ-ACK bit sequence, it does not multiplex the HARQ-ACK bit sequence for the specific transmission method that it has determined is not scheduled. For example, if the common total-DAI indicates a preset value and no PDCCHs that schedule TB-based transmission are received at all, the HARQ-ACK bit sequence generated by the terminal is configured excluding the TB-based HARQ-ACK bit sequence. Similarly, if the common total-DAI indicates a preset value and no PDCCHs are received to schedule CBG-based transmissions, the HARQ-ACK bit sequence generated by the terminal is constructed excluding the CBG-based HARQ-ACK bit sequence. On the other hand, if no PDCCHs are received to schedule PDSCHs of a specific transmission method, but the common total-DAI does not indicate a preset value, the terminal determines that a PDSCH of the specific transmission method was scheduled, but reception of the PDSCH failed. Therefore, when the terminal generates a HARQ-ACK bit sequence, it multiplexes the HARQ-ACK bit sequence for the relevant transmission method. According to an embodiment of the present invention, if a 2-bit total-DAI is used, the preset value is the binary value "11". If a 3-bit total-DAI is used, the preset value is "011" or "111". Furthermore, according to embodiments of the present invention, the method of not multiplexing the HARQ-ACK bit sequence for a specific transmission method is applicable only when the HARQ-ACK bit sequence is transmitted via PUSCH.In other words, if the common total-DAI indicates a pre-set value, no PDCCH is received to schedule the PDSCH for a specific transmission scheme, and the HARQ-ACK bit sequence is transmitted via PUSCH, the terminal will not multiplex the HARQ-ACK bit sequence for the specific transmission scheme.

[0217] On the other hand, according to the third embodiment of the present invention, the use of a common total-DAI may result in a mismatch in the total-DAI for a specific transmission method. Therefore, in the case of a specific transmission method, the terminal generates a HARQ-ACK bit sequence based on the total number information using a common total-DAI value, which differs from the total number of PDSCHs scheduled in the specific transmission method. For example, if the decoding of PDCCHs transmitted via component carriers #1 and #4 scheduled for TB-based transmission is successful, the terminal receives values ​​of 0 and 1, respectively, as counter-DAI for TB-based transmission. On the other hand, the terminal receives a value of 3 as the total-DAI for TB-based transmission. Although a total-DAI value of 3 is received for TB-based transmission, the counter-DAI value of the last PDCCH that was successfully received among the PDCCHs scheduled for TB-based transmission is 1, so the difference between the total-DAI value and the counter-DAI value of the last PDCCH is 2. Therefore, the terminal identifies that it failed to receive the two PDCCHs scheduled for TB-based transmission after the last PDCCH. Therefore, the terminal transmits a NACK as a HARQ-ACK to the PDSCH scheduled by the PDCCH identified as having failed to receive. On the other hand, the base station ignores the NACK transmitted due to the mismatch because it has the actual total number of scheduled TB-based PDSCHs, unlike the common total-DAI value.

[0218] Figures 25 and 26 show an example of generating a HARQ-ACK bit sequence based on the DAI signaled by the third embodiment described above. Figure 25 shows an example where the common total-DAI value indicates the total number of CBG-based PDSCHs, and Figure 26 shows an example where the common total-DAI value indicates the total number of TB-based PDSCHs. The method for generating a HARQ-ACK bit sequence based on the DAI signaled by the third embodiment of the present invention is similar to the first embodiment described using Figure 22. However, if the common total-DAI indicates a preset value and no PDCCHs are received to schedule PDSCHs of a specific transmission method, the terminal does not multiplex the HARQ-ACK bit sequence for the specific transmission method when generating the HARQ-ACK bit sequence.

[0219] First, referring to Figure 25, the common total-DAI value indicates the total number of CBG-based PDSCHs, and the value of the total-DAI field is 3. Since the total-DAI field consists of two bits, the total number of CBG-based PDSCHs scheduled on the entire component carrier is interpreted as 22*n+3+1=4*(n+1), and the total number of TB-based PDSCHs scheduled on the entire component carrier is interpreted as 22*m+3+1=4*(m+1) (where n and m are non-negative integers). The terminal generates the CBG-based HARQ-ACK bit sequence and the TB-based HARQ-ACK bit sequence, respectively, and combines the two HARQ-ACK bit sequences to form the overall HARQ-ACK bit sequence. According to the example in Figure 25, since the value of the total-DAI field is 3, the TB-based HARQ-ACK bit sequence includes HARQ-ACK[y0] for a 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). (2) , y0 (3)] is added. Here, a virtual PDSCH means a PDSCH that is not actually being transmitted. The terminal attaches the CBG-based HARQ-ACK bit sequence after the TB-based HARQ-ACK bit sequence to complete the HARQ-ACK bit sequence. Referring to Figure 25, the HARQ-ACK bit sequence configured by the terminal is [x0 (0) x1 (0) , ..., x N-1 (0) x0 (1) x1 (1) , ..., x N-1 (1) x0 (2) x1 (2) , ..., x N-1 (2) x0 (3) x1 (3) , ..., x N-1 (3) , y0 (0) , y0 (1) , y0 (2) , y0 (3) ]. Here, the last two bits of the TB-based HARQ-ACK bit sequence [y0 (2) , y0 (3) ] is a dummy bit containing unnecessary information, intended to prevent interpretation errors in the HARQ-ACK bit sequence between the base station and the terminal.

[0220] Next, referring to Figure 26, the common total-DAI value indicates the total number of TB-based PDSCHs, and the value of the total-DAI field is 3. If the total-DAI field consists of 2 bits, then the total number of CBG-based PDSCHs scheduled to the entire component carrier is 2. 2 *n+1+1=4*n+2, and the total number of TB-based PDSCHs scheduled for the entire component carrier is 2 2*m+1+1=4*m+2 is interpreted as (where n and m are non-negative integers). The terminal generates a CBG-based HARQ-ACK bit sequence and a TB-based HARQ-ACK bit sequence, respectively, and combines the two HARQ-ACK bit sequences to form the overall HARQ-ACK bit sequence. According to the embodiment in Figure 26, since the value of the total-DAI field is 1, the TB-based HARQ-ACK bit sequence contains HARQ-ACK[x0] for virtual CBG-based PDSCHs (i.e., CBG-tx #4, #5) in addition to the four CBG-based PDSCHs (i.e., PDSCH CBG-tx #0, #1, #2, #3). (4) x1 (4) , ..., x N-1 (4) x0 (5) x1 (5) , ..., x N-1 (5) ] is added. The terminal attaches the CBG-based HARQ-ACK bit sequence after the TB-based HARQ-ACK bit sequence to complete the HARQ-ACK bit sequence. Referring to Figure 26, the HARQ-ACK bit sequence configured by the terminal is [x0 (0) x1 (0) , ..., x N-1 (0) x0 (1) x1 (1) , ..., x N-1 (1) x0 (2) x1 (2) , ..., x N-1 (2) x0 (3) x1 (3) , ..., x N-1 (3) x0 (4) x1 (4) , ..., x N-1 (4) x0 (5) x1 (5) , ..., x N-1 (5) , y0 (0) , y0 (1) ]. Here, the last 2N bits [x0(4) x1 (4) , ..., x N-1 (4) x0 (5) x1 (5) , ..., x N-1 (5) ] is a dummy bit containing unnecessary information, intended to prevent interpretation errors in the HARQ-ACK bit sequence between the base station and the terminal.

[0221] Figure 27 shows another embodiment that generates a HARQ-ACK bit sequence based on the DAI signaled by the third embodiment described above. As described above, according to the additional embodiment of the present invention, only one of the transmission methods, CBG-based transmission or TB-based transmission, is scheduled for the PDSCH. In this case, the total-DAI value is set to a preset value of 3 (i.e., "11" in binary) to signal that only one of the transmission methods' PDSCHs is scheduled. Also, in the embodiment of Figure 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, Figure 27(a) shows an example where 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 the entire component carrier is 2, the value of Total-DAI is set to 1. In this case, it is interpreted that the total number of CBG-based PDSCHs scheduled on the entire component carrier is 2. Therefore, the terminal receives a 2*N-bit HARQ-ACK[x0] for two virtual CBG-based PDSCHs. (0) x1 (0) , ..., x N-1 (0) x0 (1) x1 (1) , ..., x N-1 (1)This generates []. Since the terminal only detects the PDCCH that schedules the TB-based PDSCH, the 2*N-bit HARQ-ACK is a dummy bit and all are set to NACK.

[0223] Next, Figure 27(b) shows an example in which the value of the total-DAI field indicates a preset value that shows no PDSCH for a particular transmission scheme is scheduled. Here, the preset value is 3 (i.e., "11" in binary). Since the received total-DAI indicates the preset value and no PDCCHs that schedule the CBG-based PDSCH have been received at all, the terminal determines that no CBG-based PDSCH is scheduled. Therefore, the terminal generates the entire HARQ-ACK bit sequence, excluding the CBG-based HARQ-ACK bit sequence and including only the TB-based HARQ-ACK bit sequence. Here, since the value of the total-DAI field is 3, the terminal interprets that the total number of TB-based PDSCHs scheduled for the entire component carrier is 4. However, since the terminal actually receives 2 TB-based PDSCHs, it receives 2-bit HARQ-ACK[y0 (2) , y0 (3) This generates a ]. The terminal schedules a virtual TB-based PDSCH. Since the PDCCH cannot be received, the aforementioned 2-bit HARQ-ACK is a dummy bit and both are set to NACK.

[0224] On the other hand, in the above-described embodiment, it was assumed that one HARQ-ACK bit is generated per TB in the TB-based HARQ-ACK bit sequence, and that N HARQ-ACK bits are generated per TB in the CBG-based HARQ-ACK bit sequence. In the following embodiment, it is assumed that one of 1 to N HARQ-ACK bits is generated per TB in the CBG-based HARQ-ACK bit sequence. For example, the length of the HARQ-ACK bits for a CBG-based PDSCH is determined based on the number of CBGs that are actually scheduled and transmitted to the PDSCH. Also, in the following embodiment, it is assumed that a TB-based transmission consists of one CBG-based transmission. That is, a PDSCH consisting of one TB is assumed to be a PDSCH consisting of one CBG, and a PDSCH consisting of two TBs is assumed to be a PDSCH consisting of two CBGs, and each embodiment is described accordingly. Therefore, the 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 that the PDSCH is scheduling, via the PDCCH information.

[0225] Figure 28 shows a DAI signaling method according to a fourth embodiment of the present invention. According to the fourth embodiment of the present invention, the base station generates a counter-DAI value and a total-DAI value based on the number of scheduled CBGs and transmits them via the counter-DAI field and the total-DAI field. That is, the counter-DAI indicates the cumulative number of scheduled CBGs from the first component carrier (i.e., component carrier #0) to the previous component carrier. The total-DAI indicates the total number of scheduled CBGs for all component carriers. Referring to Figure 28, the 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, 3, 1, 4, 3, and 3, respectively. Since the total number of CBGs scheduled across all component carriers is 16, the values ​​of the (counter-DAI, total-DAI) fields for 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 a terminal receives a PDCCH, it identifies the number of CBGs included in the PDSCH scheduled by the PDCCH via the CBG scheduling information contained in the PDCCH. The terminal also identifies the total number of CBGs scheduled on the entire component carrier via the total-DAI value and identifies the transmission order of the CBGs included in the PDSCH scheduled by the relevant PDCCH via the counter-DAI value. If the PDSCH scheduled by the current PDCCH contains k CBGs and the value of the (counter-DAI, total-DAI) field is (C, T), then the PDSCHs scheduled on the entire component carrier contain a total of T CBGs, and the CBGs included in the PDSCH scheduled by the current PDCCH are the C+1 to C+k CBGs out of the total T CBGs. For example, if a 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 contains one CBG based on the scheduling information contained in the PDCCH. Furthermore, the terminal identifies that a total of 16 CBGs are scheduled on the entire component carrier via the received (counter-DAI, total-DAI) field values ​​(5, 16), and that the CBG included in the PDSCH transmitted via component carrier #3 is the 6th of the 16 CBGs.

[0227] The terminal generates the HARQ-ACK bit sequence in the following way: 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, then the length of the HARQ-ACK bit sequence is 2 B*n+T. Here, n is a non-negative integer and is the minimum value such that the HARQ-ACK bits for the CBGs included in the PDSCH scheduled by the PDCCH that successfully received the signal are included in the HARQ-ACK bit sequence. The terminal determines the position of the HARQ-ACK bits for the CBGs scheduled by the PDCCH based on the counter-DAI value obtained from the successfully received signal and the number k of scheduled CBGs. That is, if the value of the counter-DAI field is C, the position of the HARQ-ACK bits in the HARQ-ACK bit sequence is from the C+1th to the C+kth position. If the counter-DAI field consists of A bits and the value of the counter-DAI field is C, then the possible positions of the HARQ-ACK bits are 2 A *From the m+C+1th position onwards, 2 A This extends up to the m+C+kth bit, where m is a non-negative integer. On the other hand, any bits in the HARQ-ACK bit sequence that are not mapped to a HARQ-ACK bit are set to NACK.

[0228] On the other hand, according to the fourth embodiment described above, if the terminal successfully receives a PDCCH, the total number of CBGs scheduled for the entire component carrier and the order in which the CBGs included in the PDSCH scheduled by the relevant PDCCH were transmitted are identified. However, since various numbers of CBGs are transmitted through a single PDSCH, when the terminal identifies a failure to receive multiple CBGs, it cannot identify how many PDSCHs were failed to receive.

[0229] Figure 29 shows a DAI signaling method according to a fifth embodiment of the present invention. According to the fifth embodiment of the present invention, the base station generates a first counter-DAI (i.e., counter-DAI#1) value and a first total-DAI (i.e., total-DAI#1) value based on the number of scheduled PDSCHs, and generates a second counter-DAI (i.e., counter-DAI#2) value and a second total-DAI (i.e., total-DAI#2) value based on the number of CBGs. The base station transmits the generated DAI values ​​through the first counter-DAI field, the first total-DAI field, the second counter-DAI field, and the second total-DAI field, respectively.

[0230] First, the first counter-DAI indicates the cumulative number of PDSCH(etc.) 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, then the cumulative number of PDSCH(etc.) scheduled up to the previous component carrier is C (i.e., the cumulative number of PDSCH(etc.) scheduled up to the current component carrier is C+1). Also, the first total-DAI indicates the total number of scheduled PDSCH(etc.) on all component carriers. If the value of the first total-DAI is T, then the total number of PDSCH(etc.) scheduled on all component carriers is T+1.

[0231] Next, the second counter-DAI indicates the cumulative number of scheduled CBGs from the first component carrier (i.e., component carrier #0) to the previous component carrier. The second total-DAI is determined based on the total number of scheduled CBGs for all component carriers. According to embodiments 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, respectively, from the information used for signaling. For example, if the number of scheduled CBGs up to the previous component carrier is P, and the first counter-DAI value scheduled up to the current component carrier is C1, then the second counter-DAI value C2 for the current component carrier is set to C2 = P - C1. Also, if the number of scheduled CBGs for all component carriers is Q, and the first total-DAI value is T1, then the second total-DAI value T2 is set to T2 = Q - T1.

[0232] In the embodiment shown in Figure 29, the situation in which CBG(etc.) is transmitted through each component carrier is as in the fourth embodiment described above. In this case, the values ​​of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields 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 a terminal receives a PDCCH, it identifies the number of CBGs included in the PDSCH scheduled by the PDCCH via the CBG scheduling information contained in the PDCCH. The terminal also identifies the total number of PDSCHs scheduled on the entire component carrier via the first total-DAI value and identifies the order in which the CBGs included in the PDSCH scheduled by the relevant PDSCH were transmitted via the first counter-DAI value. In addition, the terminal identifies the total number of CBGs scheduled on the entire component carrier via the second total-DAI value and identifies the order in which the CBGs included in the PDSCH scheduled by the relevant PDCCH were transmitted via the second counter-DAI value. If the PDSCH scheduled by the current PDCCH contains k CBGs, and the values ​​of the (1st counter-DAI, 1st total-DAI, 2nd counter-DAI, 2nd total-DAI) fields are (C1, T1, C2, T2), then the total number of PDSCHs scheduled on the entire component carrier 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 said 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 in accordance with the increase in the component carrier index (i.e., not in the order 0 → 1 → 2 → 3…), the terminal determines that it has failed to receive some PDCCHs. Also, if the first counter-DAI value and the first total-DAI value of the last PDCCH that was successfully received are not the same, the terminal determines that it has failed to receive at least one PDCCH after the last PDCCH. In this case, the number of PDCCHs that failed to be received after the last PDCCH that was successfully received 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. Based on the first counter-DAI value, the second counter-DAI value obtained from the PDCCH that was successfully received, and the number k of scheduled CBGs (etc.), the terminal determines the position of the HARQ-ACK bits (etc.) for the CBG scheduled by the relevant PDCCH. That is, if the values ​​of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields are (C1, T1, C2, T2), then the position of the HARQ-ACK bits (etc.) in the HARQ-ACK bit sequence is from the C1+C2+1th bit to the C1+C2+kth bit. On the other hand, bits in the HARQ-ACK bit sequence that are not mapped to the HARQ-ACK bits (etc.) are set to NACK.

[0236] On the other hand, according to the fifth embodiment described above, if the terminal successfully receives a PDCCH, the total number of CBGs scheduled for the entire component carrier and the order in which the CBGs included in the PDSCH scheduled by the relevant PDCCH were transmitted are identified. Furthermore, if the terminal fails to receive at least one PDSCH, it is possible to identify which PDSCH failed to be received. However, this embodiment has the disadvantage of high DCI overhead.

[0237] Figure 30 shows a DAI signaling method according to the sixth embodiment of the present invention. According to the sixth embodiment of the present invention, the base station generates a first counter-DAI (i.e., counter-DAI#1) value and a first total-DAI (i.e., total-DAI#1) value based on the number of scheduled PDSCHs, and generates a second counter-DAI (i.e., counter-DAI#2) value based on the number of CBGs. The base station transmits the generated DAI values ​​through the first counter-DAI field, the first total-DAI field, and the 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 on 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 k PDSCHs are scheduled from the first component carrier (i.e., component carrier #0) to the previous component carrier (where k < K), the K PDSCHs include the k PDSCHs from the first component carrier to the previous component carrier and K-k PDSCHs in reverse order 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 scheduled CBGs on all component carriers. For example, if the values of the first total-DAI are 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 on 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 by which the terminal determines that it has failed to receive some PDCCHs is the same as in the fifth embodiment described above. In addition, in the sixth embodiment, the second counter-DAI is determined based on the number of CBGs scheduled for the K PDSCHs prior to the current component carrier, so the terminal identifies the number of CBGs included in the PDSCH scheduled by the PDCCH that failed to be received based on the second counter-DAI. For example, suppose the terminal fails to receive the PDCCH with a first counter-DAI value of 2, but succeeds in receiving the remaining PDCCHs. The terminal identifies that it failed to receive the PDCCH with a first counter-DAI value of 2 because none of the first counter-DAI values ​​of the successfully received PDCCHs are 2. The number of CBGs (etc.) included in the PDSCH scheduled by the PDCCH with a first counter-DAI value of 2 is identified based on the value obtained by subtracting the number of CBGs included in the PDSCHs scheduled by the PDCCHs with first counter-DAI values ​​of 0 and 1, respectively, from the second counter-DAI value of the PDCCH with a first counter-DAI value of 3. In the embodiment shown in Figure 30, the second counter-DAI value of the PDCCH with a first counter-DAI value of 3 is 3, and the number of CBGs included in the PDSCHs scheduled by the PDCCHs with first counter-DAI values ​​of 0 and 1, respectively, is 2 and 3. Therefore, the number of CBGs x included in the PDSCH scheduled by the PDCCH with a 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] Figure 31 shows an example of generating a HARQ-ACK bit sequence based on the DAI signaled by the sixth embodiment described above. As in the embodiment described above, the terminal identifies the number of PDSCHs transmitted via the component carrier based on the value of the first counter-DAI and the value of the first total-DAI. The terminal also identifies the number of CBGs transmitted via each via the second counter-DAI value. Therefore, the terminal generates a HARQ-ACK bit sequence by sequentially increasing the value of the first total-DAI field from 0 to the first total-DAI value and combining the HARQ-ACK bits for the PDSCH scheduled by the corresponding PDCCH. However, if the value of K is 2 or greater (for example, when K=2 or 3), the terminal generates a HARQ-ACK bit sequence by cyclically increasing the value of the first total-DAI field from i and combining the HARQ-ACK bits for the PDSCH scheduled by the corresponding PDCCH. In this case, to indicate the value of i, a header indicating the configuration information of the HARQ-ACK bit sequence is added to the beginning or end of the HARQ-ACK bit sequence. In other words, the HARQ-ACK bit sequence includes a header and a main bit sequence. The header indicates information about which PDSCH the main bit sequence starts with in the HARQ-ACK bit sequence.

[0242] Referring to Figure 31, if the value of K is 2 or 3, there are four possible HARQ-ACK bit sequences that the terminal will transmit. Therefore, the header consists of two bits indicating which PDSCH's HARQ-ACK bit the main bit sequence begins with. For example, if the header indicates "00", the main bit sequence begins with the HARQ-ACK bit of the first PDSCH. Similarly, if the header indicates "01", "10", or "11", the main bit sequence begins with the HARQ-ACK bit of the second, third, or fourth PDSCH, respectively.

[0243] On the other hand, according to the sixth embodiment described above, once the terminal successfully receives a PDCCH, the total number of PDSCHs scheduled for the entire component carrier and the order in which the PDSCHs scheduled by the relevant PDCCH were transmitted are identified. The terminal also identifies information regarding the number of CBGs via the second counter-DAI value. According to the sixth embodiment, since the second total-DAI field is not transmitted, the DCI signaling overhead can be reduced compared to the fifth embodiment, but the overhead of UCI transmission increases because a head should be added to the HARQ-ACK bit sequence transmitted by the terminal.

[0244] Figure 32 shows a DAI signaling method according to the seventh embodiment of the present invention. According to the seventh embodiment of the present invention, the base station divides the transmission type into first-type transmission and second-type transmission according to the number of CBGs included in the scheduled PDSCH, and independently generates a first counter-DAI (i.e., counter-DAI#1), 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), a second total-DAI (i.e., total-DAI#2) value based on the number of CBGs for each transmission type. The base station transmits DAI values ​​of the same type as the transmission type of the PDSCH scheduled by the PDCCH via the first counter-DAI field, first total-DAI field, second counter-DAI field, and second total-DAI field of the PDCCH, respectively. When a terminal receives the PDCCH, the terminal identifies the number of CBGs included in the PDSCH scheduled by the PDCCH via the CBG scheduling information included in the PDCCH. Furthermore, the terminal identifies the transmission type of the PDSCH based on the number of CBGs contained within the PDSCH. The terminal interprets the values ​​of the first counter-DAI field, first total-DAI field, second counter-DAI field, and second total-DAI field received via the PDSCH as DAI values ​​for the identified transmission type.

[0245] According to an embodiment of the present invention, the first type of transmission is the transmission of a PDSCH consisting of a number of CBGs less than or equal to a preset number, and the second type of transmission is the transmission of a PDSCH consisting of a number of CBGs greater than the preset number. According to one embodiment, the preset number is

[0246]

number

number

number

number

number

[0247] The DAI values ​​for Type 1 transmission are applied to PDSCH and CBG based on Type 1 transmission, and the definition of the DAI values ​​is the same as in the fifth embodiment described above. Similarly, the DAI values ​​for Type 2 transmission are applied to PDSCH and CBG based on Type 2 transmission. However, in the DAI for Type 2 transmission, the first counter-DAI and the first total-DAI are set in the same way as in the fifth embodiment described above, but the second counter-DAI and the second total-DAI are set to have a different granularity than those in the fifth embodiment described above. In other words, the maximum number of minimum CBGs included in the PDSCH on which Type 2 transmission is performed is

number

number

number

[0248] Referring to Figure 32, PDSCHs are 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, 3, 1, 4, 3, and 4, respectively. If N=4, the PDSCHs scheduled to component carriers #0 and #3 are PDSCHs based on type 1 transmission, and the PDSCHs scheduled to component carriers #1, #4, #5, and #7 are PDSCHs based on type 2 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, which are scheduled to have PDSCHs based on type 1 transmission, are (0, 1, 0, 1) and (1, 1, 1, 1), respectively. Furthermore, the values ​​of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7, which are scheduled based on the second type transmission, 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 by the seventh embodiment of the present invention.

[0249] [Table 12]

[0250] Referring to Table 12, the terminal identifies the number of PDSCHs of the relevant transmission type scheduled on the component carrier, and the order in which the PDSCHs of the transmission type scheduled by the PDCCH were transmitted, via the values ​​of the first counter-DAI field and the first total-DAI field of the PDCCH. The terminal also identifies the number of CBGs contained in the PDSCHs of the relevant transmission type scheduled on the component carrier, and the order in which the CBGs contained in the PDSCHs of the transmission type scheduled by the PDCCH were transmitted, via 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 contains k CBGs (etc.), and the transmission type is x (where x=1 or 2), and the values ​​of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields are (C1, T1, C2, T2), then the total number of PDSCHs based on type-x transmission scheduled for the entire component carrier is T1+1, and the order of the PDSCH based on type-x transmission scheduled by the current PDCCH is C1+1. Also, the CBGs contained in the PDSCH based on type-x are M x *M from C1+C2+1 x *This is the CBG up to the C1+C2+kth position. Here, if x=1, then M x If = 1 and x = 2, then

number

[0251] Figure 33 shows an example of generating a HARQ-ACK bit sequence based on the DAI signaled by the seventh embodiment described above. First, the terminal combines the HARQ-ACKs for PDSCHs based on the first type transmission in the order of first counter-DAI value to generate a first type transmission-based HARQ-ACK bit sequence. The terminal also combines the HARQ-ACKs for PDSCHs based on the second type transmission in the order of first counter-DAI value to generate a second type transmission-based HARQ-ACK bit sequence. In this case, "NACK" is used as the HARQ-ACK for PDSCHs that failed to receive the PDCCH. According to one embodiment, if no PDCCHs are received to schedule the first type-based transmission, the HARQ-ACK bit sequence generated by the terminal is configured by excluding the HARQ-ACK bit sequence for the first type-based transmission. Similarly, if no PDCCHs are received to schedule the second type-based transmission, the HARQ-ACK bit sequence generated by the terminal is configured by excluding the HARQ-ACK bit sequence for the second type-based transmission. The terminal combines the HARQ-ACK bit sequence for the first type of base transmission and the HARQ-ACK bit sequence for the second type of base transmission in a predetermined order to constitute the overall HARQ-ACK bit sequence. In one embodiment, the terminal attaches the HARQ-ACK bit sequence for the first type of base transmission after the HARQ-ACK bit sequence for the second type of base transmission to constitute the overall HARQ-ACK bit sequence. Referring to Figure 33, the HARQ-ACK bit sequence configured by the terminal is [x0 (0) x1 (0) , x2 (0) x0 (1) x1 (1) , x2 (1) , x3 (1) x0 (2) x1 (2) , x2 (2) x0 (3) x1 (3) , x2 (3) , x3 (3) , y0 (0) , y1 (0), y0 (1) This is the case. However, the present invention is not limited to this, and the entire HARQ-ACK bit sequence may be constructed by combining the bit sequences in reverse order.

[0252] On the other hand, according to the seventh embodiment described above, the transmission type can be divided into first-type transmission and second-type transmission depending on the number of CBGs included in the PDSCH, and the DCI overbed can be reduced by signaling independent DAI values ​​for each transmission type. However, there is a disadvantage that terminals must always receive PDCCHs that schedule different transmission types from each other.

[0253] Figure 34 shows a DAI signaling method according to the eighth embodiment of the present invention. The eighth embodiment of the present invention is carried out by combining at least some of the configurations of the second and seventh embodiments described above. In other words, the base station divides the transmission type into first-type transmission and second-type transmission according to the number of CBGs included in the scheduled PDSCH, and independently generates a first counter-DAI (i.e., counter-DAI#1), 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), a second total-DAI (i.e., total-DAI#2) value based on the number of CBGs for each transmission type. In this case, if the value of the first counter-DAI is even, 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 via the first total-DAI field and the second total-DAI field of the PDCCH, respectively. However, if the value of the first counter-DAI is odd, the base station transmits the first total-DAI value and the second total-DAI value for a transmission type different from the PDSCH transmission type scheduled by the PDCCH, via the first total-DAI field and the second total-DAI field of the PDCCH, respectively. Here, the definition of the DAI value is the same as in the seventh embodiment described above.

[0254] In the embodiment shown in Figure 34, the situation in which CBG(etc.) is transmitted through each component carrier is the same as in the seventh embodiment described above. The PDSCHs scheduled on component carriers #0 and #3 are PDSCHs based on type 1 transmission, and the PDSCHs scheduled on component carriers #1, #4, #5, and #7 are PDSCHs based on type 2 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, which are scheduled with type 1 transmission-based PDSCHs, are (0, 1, 0, 1) and (1, 3, 1, 2), respectively. Furthermore, the values ​​of the (first counter-DAI, first total-DAI, second counter-DAI, second total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7, which are scheduled based on the second type transmission, are (0, 3, 0, 2), (1, 1, 0, 1), (2, 3, 1, 2), and (3, 1, 1, 1), respectively. On the other hand, the method for generating the HARQ-ACK bit sequence based on the DAI signaled by the eighth embodiment is as shown in the embodiment of Figure 33 described above.

[0255] On the other hand, according to the eighth embodiment described above, the transmission type can be divided into first-type transmission and second-type transmission according to the number of CBGs included in the PDSCH, and the DCI overbed can be reduced by signaling independent DAI values ​​for each transmission type. Furthermore, 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 inform the total-DAI for each of the different types.

[0256] Figure 35 shows a DAI signaling method according to the ninth embodiment of the present invention. The ninth embodiment of the present invention is carried out by combining at least some of the configurations of the third and seventh embodiments described above. That is, the base station divides the transmission type into first-type transmission and second-type transmission according to the number of CBGs included in the scheduled PDSCH, and independently 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. The base station also 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 of the above 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 to the PDCCH that schedules the corresponding PDSCH via the first counter-DAI field and the second counter-DAI field. Furthermore, regardless of the transmission type, the base station transmits a common first total-DAI value and a common second total-DAI value through the first total-DAI field and the second total-DAI field of all PDCCHs.

[0257] According to an additional embodiment, if only one transmission type PDSCH is scheduled in the entire component carrier, the common first total-DAI value is determined to a preset value. According to an embodiment of the present invention, if a 2-bit total-DAI is used, the preset value is the binary number "11". If a 3-bit total-DAI is used, the preset value is "011" or "111". On the other hand, the method for determining the first counter-DAI and second counter-DAI values ​​is the same as in the seventh embodiment described above.

[0258] In the embodiment shown in Figure 35, the situation in which CBGs are transmitted through each component carrier is the same as in the seventh embodiment described above. Furthermore, it is 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. Thus, 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, which are scheduled to have PDSCHs based on the first type transmission, are (0, 3, 0, 2) and (1, 3, 1, 2), respectively. Furthermore, the values ​​of the (First Counter-DAI, First Total-DAI, Second Counter-DAI, Second Total-DAI) fields of each PDCCH for component carriers #1, #4, #5, and #7, which are scheduled based on Type 2 transmission, are (0, 3, 0, 2), (1, 3, 0, 2), (2, 3, 1, 2), and (3, 3, 1, 2), respectively.

[0259] Figure 36 shows an example of generating a HARQ-ACK bit sequence based on the DAI signaled by the ninth embodiment described above. The HARQ-ACK bit sequence is generated in the same way as in the embodiment of Figure 33 described above. However, because (3, 2) is used instead of (1, 1) as the value of the (first total-DAI, second total-DAI) field for the PDSCH based on the first type transmission, the HARQ-ACK bit sequence additionally includes a dummy HARQ-ACK[z0, z1, z2] for three virtual CBGs contained in two virtual PDSCHs.

[0260] Figure 37 shows a DAI signaling method according to the 10th embodiment of the present invention. If the base station configures CBG-based transmission, the number of CBGs per TB configured in each component carrier or cell will be different from each other. For example, component carrier #0 has 2 CBGs per TB, while component carrier #1 has 4 CBGs per TB. Also, if the terminal is configured in a transmission mode in which two TBs are transmitted from one PDSCH, the number of CBGs per TB will be 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 bits (etc.) to the base station based on the number of configured CBGs (etc.). 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 bits (etc.) to the base station based on twice the number of CBGs (etc.) per configured TB. 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 bits (etc.) to the base station based on the number of CBGs (etc.) per configured TB. In the following embodiments of the present invention, it is assumed that the terminal is configured to perform spatial bundling or is configured in a transmission mode in which one TB is transmitted from one PDSCH. Specific embodiments of HARQ-ACK bundling methods, including spatial bundling, will be described later. However, embodiments of the present invention may be extended to terminals configured in a transmission mode in which two TBs are transmitted from one PDSCH and without spatial bundling. According to embodiments of the present invention, the DCI of the PDCCH that schedules 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 for all component carriers. Here, a CBG group is a group formed by bundling S predetermined CBGs. According to one embodiment, in the counter-DAI and total-DAI, a TB-based PDSCH is treated the same as a CBG-based transmission consisting of S CBGs. That is, it is assumed that a TB-based PDSCH contains one CBG group. Therefore, even if a terminal receives a TB-based PDSCH, it should feed back an S-bit HARQ-ACK.An S-bit HARQ-ACK is generated by repeatedly generating 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 terminal will determine that a total of 3*S CBGs have been transmitted through the entire component carrier. Therefore, the terminal should transmit a total of 3*S-bit HARQ-ACKs. If two TBs are transmitted from one PDSCH and no spatial bundling is performed, the terminal should transmit a total of 2*3*S-bit HARQ-ACKs.

[0262] Table 13 shows the number of CBGs (and other elements) indicated by each DAI value when the total-DAI field and counter-DAI field consist of two bits. Table 14 shows the number of CBGs (and other elements) indicated by each DAI value when the total-DAI field and counter-DAI field 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). That is, V DL C=DAI c is the counter-DAI value of component carrier C, and V DL T-DAIThis is the total-DAI value. According to the signaling methods in Tables 13 and 14, if the total-DAI or counter-DAI value is A, then the number of CBGs indicated by the corresponding DAI field is S*(2^B+A). Here, B is the bit width of the counter-DAI or total-DAI. According to an embodiment of the present invention, the number of CBGs S included in a single CBG group is expressed as the fineness of the number of CBGs represented by the counter-DAI or total-DAI.

[0266] According to embodiments of the present invention, the value of S, the number of CBGs in a single CBG group, can be determined in various ways. In one embodiment, the value of S is fixed at S=2. Preferably, S consists of a terminal-specific RRC signal. In another embodiment, S is determined to be the greatest common divisor of the number of CBGs configured in each component carrier. For example, if component carrier #0 has 2 CBGs and component carrier #1 has 6 CBGs, S is set to 2. Alternatively, if component carrier #0 has 4 CBGs and component carrier #1 has 8 CBGs, S is set to 4.

[0267] According to other embodiments, if the transmission mode transmits one TB from one component carrier, the value of S is fixed at S=2, and if the transmission mode transmits two TBs from one component carrier, the value of S is fixed at S=4. Furthermore, according to other embodiments, if all component carriers are configured in a transmission mode that transmits only one TB, S is determined to be the greatest common divisor of the number of CBGs configured on each component carrier. Also, if the transmission mode transmits only one TB from one component carrier, S is determined to be twice the greatest common divisor of the number of CBGs configured on each component carrier. For example, in a transmission mode where two TBs are transmitted from one component carrier, if component carrier #0 has 2 CBGs and component carrier #1 has 6 CBGs, S is set to 4. Also, if component carrier #0 has 4 CBGs and component carrier #1 has 8 CBGs, S is set to 8.

[0268] The bit widths of the counter-DAI field and total-DAI field expected by the terminal may vary depending on the number S of CBGs included in a single CBG group. In one embodiment, the bit widths of the counter-DAI field and total-DAI field are set to 2 + ceil(log2(X / S)), where X is the largest number of CBGs in each component carrier configured in the terminal, and ceil(a) is the smallest integer greater than or equal to a. For example, if the terminal has two component carriers, and component carrier #0 has 2 CBGs and component carrier #1 has 4 CBGs, then S = 2. In this case, the bit widths of the counter-DAI field and total-DAI field are set to 2 + ceil(log2(4 / 2)) = 3 bits, respectively. Also, if the terminal has two component carriers, and component carrier #0 has 4 CBGs and component carrier #1 has 8 CBGs, then S = 4. In this case, the bit widths of the counter-DAI field and the total-DAI field are set to 2 + ceil(log2(8 / 4)) = 3 bits, respectively.

[0269] Referring to Figure 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. In one embodiment of the present invention, the number of CBGs S contained in a 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] Figure 38 shows a method for compressing HARQ-ACK according to an embodiment of the present invention. If the length of the HARQ-ACK payload to be transmitted by a terminal configured with CBG-based transmission exceeds the maximum transmission capacity of PUCCH, the HARQ-ACK payload should be compressed to match the maximum transmission capacity of PUCCH.

[0271] According to an embodiment of the present invention, the terminal transmits TB-based HARQ-ACKs to some of the TBs (or PDSCHs) out of the total TBs, and transmits CBG-based HARQ-ACKs to the remaining TBs (or PDSCHs). Referring to Figure 38, the terminal's HARQ-ACK payload is composed of three parts as follows: First, the "header" section indicates how to interpret the subsequent HARQ-ACK payload. More specifically, the "header" indicates the index of the TB (or PDSCH) to which the CBG-based HARQ-ACK is transmitted. The "header" also indicates the index of the TB (or PDSCH) to which the TB-based HARQ-ACK is transmitted. Next, the "TB-A / N" field contains the TB-based HARQ-ACKs for the TBs (or PDSCHs) that the "header" instructed to transmit the TB-based HARQ-ACK. In this case, the order of the TB-based HARQ-ACKs is set in ascending order of the counter-DAI values ​​of the TBs (or PDSCHs). Next, the "CBG-A / N" field contains the CBG-based HARQ-ACKs for the TB (or PDSCH) that instructed the "Header" to transmit the CBG-based HARQ-ACK. In this case, the order of the CBG-based HARQ-ACKs is set in ascending order of the TB's (or PDSCH's) counter-DAI value. Incidentally, if the number of bits in the CBG-based HARQ-ACKs for different TBs is different, a 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 configured CBG-based HARQ-ACK among them.

[0272] The "header" section is configured as follows. If HARQ-ACKs are transmitted for a total of X TBs, the terminal transmits CBG-based HARQ-ACKs for C TBs (and others) out of the X, and TB-based HARQ-ACKs for the remaining Xc TBs (and others). The method by which the terminal and base station determine the value of c will be described later. The "header" section indicates information for selecting c TBs out of X TBs (and others). The "header" section consists of an X-bit length bitmap. Each bit indicates information about 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 TBs are selected out of X TBs (and others) is...

number

number

number

number

[0273] According to one embodiment of the present invention, the terminal and base station determine the value of c in the following manner. The base station and terminal can know the maximum number of transmission bits that a PUCCH transmitting a HARQ-ACK can transmit. Assume that the maximum number of transmission bits is B. Assume that the length of the CBG-based HARQ-ACK payload is N. The terminal and base station identify how many TBs (or PDSCHs) are scheduled in the entire component carrier via the total-DAI value. Assume that the total number of scheduled TBs (or PDSCHs) is X. In this case, c is determined to be the largest integer that satisfies the following mathematical formula 1.

[0274]

number

[0275] In the above equation 1, since the values ​​of X, N, and B are known to the terminal and the base station, the terminal and the base station can identify the value of c without error. Incidentally, once the value of c is determined, the length of the HARQ-ACK payload transmitted by the terminal is

number

[0276] For example, if X=9, B=22, and N=4, then c=2 is obtained by the above mathematical formula 1. Therefore, when the terminal generates a HARQ-ACK, it configures an N-bit CBG-based HARQ-ACK for 2 of the 9 TBs (or PDSCHs) and a 1-bit TB-based HARQ-ACK for the remaining 7 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 above HARQ-ACK, the "header"

number

[0277] Figures 39 to 40 show a method for performing spatial bundling of HARQ-ACKs according to an embodiment of the present invention. In a single PDSCH, a terminal configured with a transmission mode in which two TBs are transmitted, and configured with CBG-based transmission, performs spatial bundling, so that the CBG-based HARQ-ACKs for each TB are bundled together. The terminal is configured to perform spatial bundling of CBG-based HARQ-ACKs transmitted through different slots. The method for performing spatial bundling according to an embodiment of the present invention is as follows. Incidentally, the method for performing spatial bundling is described, but this 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 for each TB. At this time, if M1 < N, it can be expressed that the corresponding TB contains M1 CBG(s) and N - M1 virtual CBG(s). The N-bit HARQ-ACK for TB#1 is [a1, a2, …, a M1 , x, …, x], and assume that the N-bit HARQ-ACK for TB#2 is [b1, b2, …, 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]

[0281] ​ Referring to Table 15, if M1=4 and M2=2, the index values ​​for the CBGs that are bundled are {1, 4}. Therefore, referring to Figure 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 index values ​​for the CBGs that are bundled are {1, 2, 4}. Therefore, referring to Figure 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 other methods for performing spatial bundling according to the first embodiment described above. If M1=N, the index of the CBG to be bundled among the TBs will follow the values ​​in Table 16, based on the M1 and M2 values.

[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 that are bundled. Therefore, 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 for performing spatial bundling of HARQ-ACK. More specifically, FIGS. 40(a) to 40(f) show respective embodiments for 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 on 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 on 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 NACK of N-(M1 + M2)-bit. 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 on which spatial bundling is performed are configured by performing bundling (i.e., binary AND operation) on 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 on 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, [b1, b2,..., b M2 is divided into [b1, b2,..., b M2-k and [b M2-k+1 , b M2-k+2 ,..., b M2 . Here, k = k = N - M1. Then, a binary AND operation is performed on [b1, b2,..., b M2-k and [a1, a2,..., a M2-k . The result obtained in this way is [c1, c2,..., c M2-kIt can be said that the final bundled HARQ-ACK was [c1, c2, ..., c M2-k ], [a M2-k+1 a M2-k+1 , ..., a M1 ], [b M2-k+1 , b M2-k+2 , ..., b M2 It is obtained by sequentially concatenating ]. According to an embodiment of the present invention, the concatenation order of the HARQ-ACKs can be switched. Incidentally, if the length of the HARQ-ACK thus concatenated is less than N-bit, x is added after the HARQ-ACK to make it N-bit. In this case, x is mapped to NACK. Finally, the bundled HARQ-ACKs are obtained by sequentially concatenating [o1, o2, ..., o N If we assume this, the number of bits in the HARQ-ACK depends on the value of index i: O i This can be obtained as shown in mathematical formula 2.

[0287]

number

[0288] Here, & represents a 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] As another embodiment of the present invention, the HARQ-ACK that has been finally bundled is [o1, o2, ..., o N If we assume this, the number of bits in the HARQ-ACK depends on the value of index i: O i It can be obtained as shown in mathematical formula 3.

[0290]

number

[0291] Here, λ is M1 + M2 - N. Also, x is mapped to NACK.

[0292] Referring to Mathematical Equations 2 and 3, and Figure 40, the HARQ-ACK that is finally bundled by the HARQ-ACK for two TBs is as follows: Referring to Figure 40(a), if the HARQ-ACKs for two TBs are [a1, x, x, x] and [b1, x, x, x], then the final bundled HARQ-ACK is [a1, b1, x, x]. Referring to Figure 40(b), if the HARQ-ACKs for two TBs are [a1, a2, x, x] and [b1, x, x, x], then the final bundled HARQ-ACK is [a1, a2, b1, x]. Referring to Figure 40(c), if the HARQ-ACKs for two TBs are [a1, a2, x, x] and [b1, b2, x, x], then the final bundled HARQ-ACK is [a1, a2, b1, b2]. Referring to Figure 40(d), if the HARQ-ACKs for the two TBs are [a1, a2, a3, x] and [b1, x, x, x], then the HARQ-ACK after final bundling is [a1, a2, a3, b1]. Referring to Figure 40(e), if the HARQ-ACKs for the two TBs are [a1, a2, a3, x] and [b1, b2, x, x], then the HARQ-ACK after final bundling is [a1&b1, a2, a3, b2]. Here, & represents a binary AND operation. Referring to Figure 40(f), if the HARQ-ACKs for the two TBs are [a1, a2, a3, x] and [b1, b2, b3, x], then the HARQ-ACK after final bundling is [a1&b1, a2&b2, a3, b3]. Furthermore, if the HARQ-ACKs for the two TBs are [a1, a2, a3, a4] and [b1, b2, b3, x], then the HARQ-ACK after final bundling is [a1&b1, a2&b2, a3&b3, a4].

[0293] Figures 41 and 42 illustrate in more detail the method for performing spatial bundling of HARQ-ACK according to an embodiment of the present invention. In Figures 41 and 42, N is the maximum number of CBGs per TB consisting of RRC signals, M1 is the number of CBG(ar) contained in TB#1, and M2 is the number of CBG(ar) contained in TB#2. Also, the HARQ-ACK bit for the i-th CBG of TB#1 is a i Therefore, the HARQ-ACK bit for the i-th CBG of TB#2 is b i The & symbol represents a binary AND operation. Also, x is mapped to NACK.

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

[0295] According to another embodiment of the present invention, if there is at least one virtual CBG between the two TBs to be bundled, the bundling is performed as follows. First, the NACK is mapped to the HARQ-ACK "x" for the virtual CBG. Also, Q = min(M1, M2). For reference, if TB#1 is TB-underground transmission, we assume that M1=1, and if TB#2 is TB-underground transmission, we assume that M2=1. The ACK is 1 and the NACK is 0. When generating the bundled HARQ-ACK from the HARQ-ACKs for the two TBs, a binary AND operation is performed on the first to Q HARQ-ACK bits, and a binary OR operation is performed on the Q+1 to N HARQ-ACK bits. If TB#1 contains 4 CBGs (i.e., M1=4) and has 4 CBGs (i.e., N=4), and TB#2 contains 2 CBGs (i.e., M2=2) and has 4 CBGs (i.e., N=4), then the HARQ-ACK for TB#1 is [a1, a2, a3, a4] and the HARQ-ACK for TB#2 is [b1, b2, 0, 0]. And Q=2. Therefore, a binary AND operation is performed on the first two bits, and a binary OR operation is performed on the last two bits (i.e., NQ). ​​Thus, the bundled HARQ-ACK is [a1&b1, a2&b2, a3|0, a4|0]. Here, & is a binary AND operation and | is a binary OR operation. Incidentally, this bundling method is used in spatial bundling, or only in bundling between other TBs excluding spatial bundling.

[0296] According to yet another embodiment of the present invention, if there is at least one virtual CBG in the two TBs to be bundled, the bundling is performed as follows. First, the HARQ-ACK for the virtual CBG is denoted as "x", and the NACK is mapped to "x" after bundling. When generating the bundled HARQ-ACK from the HARQ-ACKs of the two TBs, a ternary AND operation is performed on the two HARQ-ACKs. The truth table for this ternary AND operation is shown in Table 17. After bundling, x is mapped to the NACK. If TB#1 contains 4 CBGs (i.e., M1=4) and the number of CBGs composed is 4 (i.e., N=4), and TB#2 contains 2 CBGs (i.e., M2=2) and the number of CBGs composed is 4 (i.e., N=4), then the HARQ-ACK for TB#1 is [a1, a2, a3, a4] and the HARQ-ACK for TB#2 is [b1, b2, x, x]. Therefore, the bundled HARQ-ACK is [a1\b1, a2\b2, a3\x, a4\x]. Here, the operator \ is shown in Table 17. Incidentally, this bundling method is used in spatial bundling, or only in bundling between other TBs excluding 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 for the terminal to determine which CBG it has received is as follows. The terminal identifies whether the corresponding TB has been transmitted via 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 i-th HARQ-ACK bit for which spatial bundling is performed is calculated by performing a binary AND operation on the HARQ-ACK bit for the k-th CBG of TB#1 and the HARQ-ACK bit for the j-th CBG of TB#2, if the i-th bit of the N-bit CBGTI in the DCI is 1, it indicates that the k-th CBG of TB#1 has been transmitted and the j-th 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 i-th bit of the N-bit CBGTI [d1, d2, …, d N is 1, it identifies that the following CBG has been transmitted.

[0299] [Number]

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

[0301] Figure 43 is a block diagram showing the configuration of a terminal and a base station according to one embodiment of the present invention. In one embodiment of the present invention, the terminal is embodied in various types of wireless communication devices or computing devices that compensate for portability and mobility. The terminal is referred to as UE (User Equipment), STA (Station), MS (Mobile Subscriber), etc. In the embodiment of the present invention, the base station controls and manages the cells (e.g., macrocells, femtocells, picocells, etc.) in the 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 in the figure, a terminal 100 according to one 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 instructions 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 units. Here, the processor 110 is configured to perform the operations described in the embodiment of the present invention. For example, the processor 110 may receive slot configuration information, determine the slot configuration based on that information, 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 connectivity using a wireless LAN. To this end, the communication module 120 incorporates multiple network interface cards (NICs), such as cellular communication interface cards 121, 121 and unlicensed band communication interface card 123, either internally or externally. In the drawing, the communication module 120 is shown as an integrated module, but each network interface card may be arranged independently depending on the circuit configuration or application, contrary to the drawing.

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

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

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

[0308] Next, the memory 130 stores control programs used by the terminal 100 and various data associated with them. Such control programs include predetermined programs necessary for the terminal 100 to communicate wirelessly with at least one of the following: a base station 200, an external device, or a server.

[0309] Next, the user interface 140 includes various forms of input / output means provided in the terminal 100. In other words, 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. The user interface 140 also outputs based on instructions from the processor 110 using various output means.

[0310] Next, the display unit 150 outputs various images to the display screen. The display unit 150 outputs various display objects, such as content generated by the processor 110 or user interfaces based on control instructions from the processor 110.

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

[0312] First, the processor 210 executes various instructions or programs to process data within the base station 200. The processor 210 also controls the overall operation of the base station 200, including each unit, and controls the transmission and reception of data between units. Here, the processor 210 is configured to perform the operations described in the embodiment of 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 connectivity using a wireless LAN. To this end, the communication module 120 incorporates multiple network interface cards, such as cellular communication interface cards 221 and 222, and an unlicensed band communication interface card 223, either internally or externally. In the drawing, the communication module 220 is shown as an integrated module, but each network interface card may be arranged independently depending on the circuit configuration or application, contrary to the drawing.

[0314] The cellular communication interface card 221 transmits and receives wireless signals to and from at least one of the terminal 100, external devices, and servers described above via a mobile communication network, and provides cellular communication services in the first frequency band based on instructions from the processor 210. According to one embodiment, the cellular communication interface card 221 includes at least one NIC module that utilizes a frequency band of less than 6 GHz. In the cellular communication interface card 221, at least one NIC module independently performs cellular communication with at least one of the terminal 100, external devices, and servers, according to the cellular communication standard or protocol of the frequency band of less than 6 GHz supported by the 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 cellular communication services in a second frequency band based on instructions from the processor 210. In one embodiment, the cellular communication interface card 222 includes at least one NIC module that utilizes several frequency bands of 6 GHz or higher. 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 the cellular communication standard or protocol of the 6 GHz or higher frequency band supported by the 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, or a server via the third frequency band, which is an unlicensed band, and provides communication services in the unlicensed band based on instructions from the processor 210. The unlicensed band communication interface card 223 includes at least one NIC module that utilizes the unlicensed band. For example, the unlicensed band may be a 2.4GHz or 5GHz band. At least one NIC module of the unlicensed band communication interface card 223 independently or dependently performs cellular communication with at least one of the terminal 100, an external device, or a server, depending on the unlicensed band communication standard or protocol of the frequency band supported by the NIC module.

[0317] The terminal 100 and base station 200 shown in Figure 43 are block diagrams according to one embodiment of the present invention, and the separately shown blocks are illustrations that logically distinguish and represent the elements of the device. Therefore, the above-mentioned elements of the device are mounted on one chip or multiple chips depending on the device design. Furthermore, 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 needed.

[0318] The above description of the present invention is illustrative, and a person with ordinary skill in the art to which the invention pertains should understand that it can be easily modified into other specific forms without altering the technical idea or essential features of the invention. Therefore, the above-described embodiments should be understood to be illustrative and not limiting in all respects. For example, each component described as a single form may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0319] The scope of the present invention is indicated by the claims described below rather than by the detailed description above, and all modifications or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereto should be interpreted as being included within the scope of the present invention. [Explanation of symbols]

[0320] 110 processors 121 Cellular communication interface card (first frequency band) 122 Cellular communication interface card (second frequency band) 123 Unlicensed Band Communication Interface Card (Third Frequency Band) 130 memory 140 User Interfaces 150 display units 210 processors 221 Cellular communication interface card (first frequency band) 222 Cellular communication interface card (second frequency band) 223 Unlicensed Band Communication Interface Card (Third Frequency Band) 230 memory

Claims

1. A user terminal configured to operate in a wireless communication system, Communication module and A processor configured to control the aforementioned communication module, The processor is configured to receive multiple downlink control information (DCI), Multiple cells for receiving a physical downlink shared channel (PDSCH) include i) at least one CBG cell configured with a code block group (CBG) - underlying PDSCH transmission, and ii) at least one TB cell configured with a transmission block (TB) - underlying PDSCH transmission. Each of the aforementioned DCIs is either a first DCI format or a second DCI format among the multiple DCI formats. For PDSCH transmission in at least one CBG cell, i) the first DCI format schedules TB-based PDSCH reception, and ii) the second DCI format schedules CBG-based PDSCH reception. A user terminal in which the processor is configured to perform TB-based PDSCH reception and CBG-based PDSCH reception in the plurality of cells.

2. The processor generates a HARQ-ACK codebook that includes a first HARQ-ACK bit sequence corresponding to the TB-based PDSCH reception and a second HARQ-ACK bit sequence corresponding to the CBG-based PDSCH reception. The user terminal according to claim 1, further configured to transmit HARQ-ACK information, including the HARQ-ACK codebook.

3. i) the first DCI format includes a counter downlink assignment index (DAI), and ii) the second DCI format includes the counter-DAI and the total-DAI, wherein the pair of the counter-DAI and the total-DAI included in the second DCI format is separately applied to either the first HARQ-ACK bit sequence or the second HARQ-ACK bit sequence, according to claim 2.

4. The user terminal according to claim 2, wherein the HARQ-ACK codebook is generated by adding the second HARQ-ACK bit sequence to the first HARQ-ACK bit sequence.

5. The user terminal according to claim 2, wherein each bit of the first HARQ-ACK bit sequence is generated for each transmission block.

6. The second HARQ-ACK bit sequence for the CBG-based PDSCH reception includes N HARQ-ACK bits for each transmission block. The user terminal according to claim 2, wherein N is the number of CBGs configured for the user terminal.

7. A wireless communication method performed by a user terminal configured to operate in a wireless communication system, The step of receiving multiple downlink control information (DCI), Multiple cells for receiving a physical downlink shared channel (PDSCH) include i) at least one CBG cell configured with a code block group (CBG) - underlying PDSCH transmission, and ii) at least one TB cell configured with a transmission block (TB) - underlying PDSCH transmission. Each of the aforementioned DCIs is either a first DCI format or a second DCI format among the multiple DCI formats. For PDSCH transmission in at least one CBG cell, i) the first DCI format schedules TB-based PDSCH reception, and ii) the second DCI format schedules CBG-based PDSCH reception, A method comprising the step of performing TB-based PDSCH reception and CBG-based PDSCH reception in the plurality of cells.

8. The steps include generating a HARQ-ACK codebook that includes a first HARQ-ACK bit sequence corresponding to the TB-based PDSCH reception and a second HARQ-ACK bit sequence corresponding to the CBG-based PDSCH reception, The method according to claim 7, further comprising the step of transmitting HARQ-ACK information, including the HARQ-ACK codebook.

9. The method according to claim 8, i) the first DCI format includes a counter downlink assignment index (DAI), and ii) the second DCI format includes the counter-DAI and the total-DAI, wherein the pair of the counter-DAI and the total-DAI included in the second DCI format is separately applied to either the first HARQ-ACK bit sequence or the second HARQ-ACK bit sequence.

10. The method according to claim 8, wherein the HARQ-ACK codebook is generated by adding the second HARQ-ACK bit sequence to the first HARQ-ACK bit sequence.

11. The method according to claim 8, wherein each bit of the first HARQ-ACK bit sequence is generated for each transmission block.

12. The second HARQ-ACK bit sequence for the CBG-based PDSCH reception includes N HARQ-ACK bits for each transmission block. The method according to claim 8, wherein N is the number of CBGs configured for the user terminal.

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