METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING RADIO SIGNALS IN A WIRELESS COMMUNICATION SYSTEM

Abstract

The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for receiving information about N code block groups defined by a transport block from a base station via an upper-layer signal, receiving a first transport block comprising a plurality of code blocks from the base station via a physical-layer channel, and transmitting the HARQ-ACK payload, which includes HARQ-ACK information in the first transport block, to the base station. Preferably, a code block-based CRC is attached to each of the code blocks, a transport block-based CRC is attached to each of the transport blocks, and the HARQ-ACK payload comprises a plurality of HARQ-ACK bits corresponding to M code block groups for the first transport block.

Description

Method and device for transmitting and receiving wireless signals in a wireless communication system

[0001] The present invention relates to a wireless communication system, and more particularly, to a method and device for transmitting and receiving wireless signals. The wireless communication system includes a CA (Carrier Aggregation)-based wireless communication system.

[0002] Wireless communication systems are widely deployed to provide various types of communication services, such as voice and data. Typically, wireless communication systems are multiple access systems that support communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power). Examples of multiple access systems include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA).

[0003] The purpose of the present invention is to provide a method for efficiently performing a wireless signal transmission and reception process and a device therefor.

[0004] The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0005] In one aspect of the present invention, a method for transmitting control information by a terminal in a wireless communication system is provided, comprising: receiving information regarding the number M of code block groups defined for one transmission block from a base station through a higher layer signal; receiving a first transmission block including a plurality of code blocks from the base station through a physical layer channel; and transmitting a HARQ-ACK payload including HARQ-ACK (Hybrid ARQ Acknowledgement) information regarding the first transmission block to the base station, wherein a code block-based CRC (Cyclic Redundancy Check) is added to each code block, a transmission block-based CRC is added to the first transmission block, and the HARQ-ACK payload includes a plurality of HARQ-ACK bits corresponding to M code block groups for the first transmission block.

[0006] In another aspect of the present invention, a terminal used in a wireless communication system is provided, comprising: an RF (Radio Frequency) module; and a processor, wherein the processor is configured to receive information about the number M of code block groups defined for one transport block from a base station through an upper layer signal, receive a first transport block including a plurality of code blocks from the base station through a physical layer channel, and transmit a HARQ-ACK payload including HARQ-ACK (Hybrid ARQ Acknowledgement) information about the first transport block to the base station, wherein a code block-based CRC (Cyclic Redundancy Check) is added to each code block, a transport block-based CRC is added to the first transport block, and the HARQ-ACK payload includes a plurality of HARQ-ACK bits corresponding to M code block groups for the first transport block.

[0007] Preferably, the upper layer signal may include an RRC (Radio Resource Control) signal, and the physical layer channel may include a PDSCH (Physical Downlink Shared Channel).

[0008] Preferably, the size of the HARQ-ACK payload can be kept the same based on M during the HARQ process for the first transmission block.

[0009] Preferably, when the first transmission block is composed of a plurality of code block groups, some of the plurality of code block groups include a ceiling (K / M) number of code blocks, and the rest of the plurality of code block groups include a flooring (K / M) number of code blocks, where ceiling is a rounding function, flooring is a rounding function, and K may represent the number of code blocks in the first transmission block.

[0010] Preferably, when a code block group is set for the first transmission block, each HARQ-ACK bit in the HARQ-ACK payload can represent each HARQ-ACK information generated in units of code block groups for the first transmission block.

[0011] Preferably, when a code block group is not set for the first transmission block, all of the plurality of HARQ-ACK bits for the first transmission block in the HARQ-ACK payload have the same value, and each HARQ-ACK bit for the first transmission block can indicate HARQ-ACK information generated in units of transmission block groups for the first transmission block.

[0012] Preferably, if all code block group-based CRC check results for the first transport block are successful, but all transport block-based CRC check results are failed, all of the multiple HARQ-ACK bits for the first transport block in the HARQ-ACK payload may indicate NACK (Negative Acknowledgement).

[0013] In another aspect of the present invention, a method for a base station to receive control information in a wireless communication system is provided, comprising: transmitting information regarding the number M of code block groups defined for one transmission block to a terminal through a higher layer signal; transmitting a first transmission block including a plurality of code blocks to the terminal through a physical layer channel; and receiving, from the terminal, a HARQ-ACK payload including HARQ-ACK (Hybrid ARQ Acknowledgement) information regarding the first transmission block, wherein a code block-based CRC (Cyclic Redundancy Check) is added to each code block, a transmission block-based CRC is added to the first transmission block, and the HARQ-ACK payload includes a plurality of HARQ-ACK bits corresponding to M code block groups for the first transmission block.

[0014] In another aspect of the present invention, a base station used in a wireless communication system is provided, comprising: an RF (Radio Frequency) module; and a processor, wherein the processor is configured to transmit information regarding the number M of code block groups defined for one transmission block to a terminal through an upper layer signal, transmit a first transmission block including a plurality of code blocks to the terminal through a physical layer channel, and receive, from the terminal, an HARQ-ACK payload including HARQ-ACK (Hybrid ARQ Acknowledgement) information regarding the first transmission block, wherein a code block-based CRC (Cyclic Redundancy Check) is added to each code block, a transmission block-based CRC is added to the first transmission block, and the HARQ-ACK payload includes a plurality of HARQ-ACK bits corresponding to M code block groups for the first transmission block.

[0015] According to the present invention, wireless signal transmission and reception can be efficiently performed in a wireless communication system.

[0016] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0017] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present invention, provide embodiments of the present invention and, together with the detailed description, explain the technical idea of ​​the present invention.

[0018] Figure 1 illustrates physical channels used in a 3GPP LTE(-A) system, which is an example of a wireless communication system, and a general signal transmission method using the channels.

[0019] Figure 2 illustrates the structure of a radio frame.

[0020] Figure 3 illustrates a resource grid of a downlink slot.

[0021] Figure 4 shows the structure of a downlink subframe.

[0022] Figure 5 illustrates an enhanced Physical Downlink Control Channel (EPDCCH).

[0023] Figure 6 illustrates the structure of an uplink subframe used in LTE(-A).

[0024] Figure 7 illustrates SC-FDMA (Single Carrier Frequency Division multiple access) and OFDMA (Orthogonal Frequency Division multiple access) methods.

[0025] Figure 8 illustrates an UL HARQ (Uplink Hybrid Automatic Repeat reQuest) operation.

[0026] Figure 9 illustrates a transport block (TB) processing process.

[0027] Figures 10 and 11 illustrate the random access process.

[0028] Figure 12 illustrates a carrier aggregation (CA) communication system.

[0029] Figure 13 illustrates cross-carrier scheduling.

[0030] Figure 14 illustrates analog beamforming.

[0031] Figure 15 illustrates the structure of a self-contained subframe.

[0032] Figures 16 and 17 illustrate signal transmission according to the present invention.

[0033] Figure 18 illustrates a base station and a terminal applicable to the present invention.

[0034] The following technologies can be used in various wireless 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 can be implemented with radio technologies such as UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA can be implemented with radio technologies such as GSM (Global System for Mobile communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA can be implemented with radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (Evolved UTRA). UTRA is a part of UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (long term evolution) is part of E-UMTS (Evolved UMTS) using E-UTRA, and LTE-A (Advanced) is an evolved version of 3GPP LTE. For clarity, this description focuses on 3GPP LTE / LTE-A, but the technical concepts of the present invention are not limited thereto.

[0035] In a wireless communication system, a terminal receives information from a base station via the downlink (DL) and transmits it to the base station via the uplink (UL). The information transmitted and received between the base station and the terminal includes data and various control information, and various physical channels exist depending on the type and purpose of the information being transmitted and received.

[0036] Figure 1 is a drawing for explaining physical channels used in a 3GPP LTE(-A) system and a general signal transmission method using them.

[0037] When a terminal is powered on again from a powered-off state or newly enters a cell, it performs an initial cell search operation, such as synchronizing with the base station, in step S101. To this end, the terminal receives a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station to synchronize with the base station and obtain information such as a cell ID. After that, the terminal can obtain broadcast information within the cell by receiving a Physical Broadcast Channel (PBCH) from the base station. Meanwhile, the terminal can check the downlink channel status by receiving a Downlink Reference Signal (DL RS) during the initial cell search phase.

[0038] After completing the initial cell search, the terminal can obtain more specific system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) based on the physical downlink control channel information in step S102.

[0039] Thereafter, the terminal may perform a random access procedure such as steps S103 to S106 to complete connection to the base station. To this end, the terminal may transmit a preamble through a physical random access channel (PRACH) (S103) and receive a response message to the preamble through a physical downlink control channel and a corresponding physical downlink shared channel (S104). In the case of contention-based random access, a contention resolution procedure such as transmission of an additional physical random access channel (S105) and reception of a physical downlink control channel and a corresponding physical downlink shared channel (S106) may be performed.

[0040] A terminal that has performed the procedure described above can then perform general uplink / downlink signal transmission procedures, such as receiving a physical downlink control channel / physical downlink shared channel (S107) and transmitting a physical uplink shared channel (PUSCH, Physical Uplink Control Channel, PUCCH) / physical uplink control channel (PUCCH) (S108). Control information transmitted by the terminal to the base station is collectively referred to as uplink control information (UCI). UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and reQuest Acknowledgement / Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), etc. CSI includes CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indication), etc. UCI is typically transmitted over the PUCCH, but can also be transmitted over the PUSCH when control information and traffic data must be transmitted simultaneously. Additionally, UCI can be transmitted aperiodically over the PUSCH at the network's request / direction.

[0041] Figure 2 illustrates the structure of a radio frame. Uplink / downlink data packet transmission occurs in subframe units, and a subframe is defined as a time interval containing multiple symbols. The 3GPP LTE standard supports a Type 1 radio frame structure applicable to Frequency Division Duplex (FDD) and a Type 2 radio frame structure applicable to Time Division Duplex (TDD).

[0042] Figure 2(a) illustrates the structure of a Type 1 radio frame. A downlink radio frame consists of 10 subframes, and each subframe consists of two slots in the time domain. The time it takes for one subframe to be transmitted is called the transmission time interval (TTI). For example, the length of one subframe may be 1 ms, and the length of one slot may be 0.5 ms. One slot includes multiple OFDM symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. Since the 3GPP LTE system uses OFDM in the downlink, an OFDM symbol represents one symbol period. An OFDM symbol may also be referred to as an SC-FDMA symbol or symbol period. A resource block (RB), as a resource allocation unit, may include multiple consecutive subcarriers in one slot.

[0043] The number of OFDM symbols included in a slot may vary depending on the configuration of the CP (Cyclic Prefix). CPs include extended CP and normal CP. For example, if an OFDM symbol is configured by a normal CP, the number of OFDM symbols included in one slot may be 7. If an OFDM symbol is configured by an extended CP, the length of one OFDM symbol increases, so the number of OFDM symbols included in one slot is fewer than in the case of a normal CP. For example, in the case of an extended CP, the number of OFDM symbols included in one slot may be 6. In cases where the channel condition is unstable, such as when a terminal moves at a high speed, an extended CP may be used to further reduce inter-symbol interference.

[0044] When normal CP is used, a slot contains 7 OFDM symbols, so a subframe contains 14 OFDM symbols. Up to the first 3 OFDM symbols of a subframe can be allocated to the physical downlink control channel (PDCCH), and the remaining OFDM symbols can be allocated to the physical downlink shared channel (PDSCH).

[0045] Figure 2(b) illustrates the structure of a Type 2 radio frame. A Type 2 radio frame consists of two half frames. Each half frame includes four (five) general subframes and one (0) special subframe. The general subframe is used for uplink or downlink depending on the UL-DL configuration. Each subframe consists of two slots.

[0046] Table 1 illustrates the subframe configuration within a radio frame according to the UL-DL configuration.

[0047] Uplink-downlink configurationDownlink-to-Uplink Switch point periodicitySubframe number012345678905msDSUUUDSUUU15msDSUUDDSUUD25msDSUDDDSUDD310msDSUUUDDDDD410msDSUUDDDDDDD510msDSUDDDDDDD65msDSUUUDSUUD

[0048] In the table, D represents a downlink subframe, U represents an uplink subframe, and S represents a special subframe. Special subframes include a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS). The DwPTS is used for initial cell search, synchronization, or channel estimation at the terminal. The UpPTS is used to synchronize the channel estimation at the base station and the uplink transmission of the terminal. The guard period is a period to remove interference in the uplink caused by the multipath delay of the downlink signal between the uplink and downlink.

[0049] The structure of a radio frame is only an example, and the number of subframes, number of slots, and number of symbols in a radio frame can be changed in various ways.

[0050] Figure 3 illustrates a resource grid of a downlink slot.

[0051] Referring to FIG. 3, a downlink slot includes multiple OFDM symbols in the time domain. Here, one downlink slot includes 7 OFDM symbols, and one resource block (RB) includes 12 subcarriers in the frequency domain. However, the present invention is not limited thereto. Each element on the resource grid is referred to as a resource element (RE). One RB includes 12×7 REs. The number of RBs included in a downlink slot, NDL, depends on the downlink transmission bandwidth. The structure of an uplink slot may be identical to the structure of a downlink slot.

[0052] Figure 4 illustrates the structure of a downlink subframe.

[0053] Referring to FIG. 4, up to 3 (4) OFDM symbols located in front of the first slot within a subframe correspond to a control region to which control channels are allocated. The remaining OFDM symbols correspond to a data region to which a physical downlink shared chancel (PDSCH) is allocated, and the basic resource unit of the data region is an RB. Examples of downlink control channels used in LTE include a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), and a physical hybrid ARQ indicator channel (PHICH). The PCFICH is transmitted in the first OFDM symbol of a subframe and carries information about the number of OFDM symbols used for transmission of the control channel within the subframe. The PHICH is a response to uplink transmission and carries a HARQ ACK / NACK (acknowledgment / negative-acknowledgment) signal. The control information transmitted via the PDCCH is referred to as downlink control information (DCI). DCI contains uplink or downlink scheduling information or an uplink transmit power control command for an arbitrary group of terminals.

[0054] Control information transmitted via PDCCH is called DCI (Downlink Control Information). DCI formats are defined as formats 0, 3, 3A, and 4 for uplink, and formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, and 2C for downlink. Depending on the DCI format, the type of information field, the number of information fields, and the number of bits in each information field vary. For example, the DCI format selectively includes information such as a hopping flag, RB assignment, modulation coding scheme (MCS), redundancy version (RV), new data indicator (NDI), transmit power control (TPC), HARQ process number, and precoding matrix indicator (PMI) confirmation depending on the purpose. Therefore, the size of the control information that matches the DCI format varies depending on the DCI format. Meanwhile, any DCI format can be used to transmit two or more types of control information. For example, DCI format 0 / 1A is used to carry DCI format 0 or DCI format 1, which are distinguished by a flag field.

[0055] The PDCCH carries the transmission format and resource allocation of the DL-SCH (downlink shared channel), resource allocation information for the UL-SCH (uplink shared channel), paging information for the PCH (paging channel), system information on the DL-SCH, resource allocation information for upper-layer control messages such as random access responses transmitted on the PDSCH, transmission power control commands for individual terminals within a certain terminal group, activation of VoIP (voice over IP), etc. Multiple PDCCHs can be transmitted within the control region. Terminals can monitor multiple PDCCHs. The PDCCH is transmitted on an aggregation of one or more consecutive CCEs (consecutive control channel elements). A CCE is a logical allocation unit used to provide a PDCCH with a predetermined coding rate depending on the state of the wireless channel. A CCE corresponds to multiple REGs (resource element groups). The format of the PDCCH and the number of bits available for the PDCCH are determined based on the correlation between the number of CCEs and the code rate provided by the CCEs. The base station determines the PDCCH format according to the DCI to be transmitted to the terminal and adds a cyclic redundancy check (CRC) to the control information. The CRC is masked with a unique identifier (referred to as a radio network temporary identifier (RNTI)) depending on the owner or usage of the PDCCH. If the PDCCH is for a specific terminal, the unique identifier of the terminal (e.g., C-RNTI (cell-RNTI)) is masked in the CRC. As another example, if the PDCCH is for a paging message, the paging indication identifier (e.g., P-RNTI (paging-RNTI)) is masked in the CRC.If the PDCCH is about system information (more specifically, a system information block (SIB) described below), a system information identifier (e.g., a system information RNTI (SI-RNTI)) is masked in the CRC. A random access-RNTI (RA-RNTI) is masked in the CRC to indicate a random access response, which is a response to the UE's transmission of a random access preamble.

[0056] The PDCCH carries a message known as Downlink Control Information (DCI), which contains resource allocation and other control information for a single terminal or a group of terminals. Typically, multiple PDCCHs can be transmitted within a single subframe. Each PDCCH is transmitted using one or more Control Channel Elements (CCEs), each of which corresponds to nine sets of four resource elements. These four resource elements are referred to as a Resource Element Group (REG). Four QPSK symbols are mapped to one REG. Resource elements assigned to reference signals are not included in a REG, so the total number of REGs within a given OFDM symbol varies depending on the presence or absence of cell-specific reference signals. The REG concept (i.e., group-wise mapping, with each group containing four resource elements) is also used for other downlink control channels (PCFICH and PHICH). That is, the REG serves as the basic resource unit in the control region. Four PDCCH formats are supported, as listed in Table 2.

[0057] PDCCH formatNumberof CCEs (n)Number of REGsNumberof PDCCH bits0197212814424362883572576

[0058] CCEs are numbered sequentially and used, and to simplify the decoding process, a PDCCH with a format consisting of n CCEs can only start from a CCE whose number is a multiple of n. The number of CCEs used for transmission of a specific PDCCH is determined by the base station depending on channel conditions. For example, if the PDCCH is intended for a terminal with a good downlink channel (e.g., close to the base station), one CCE may be sufficient. However, for a terminal with a poor channel (e.g., close to the cell edge), eight CCEs may be used to achieve sufficient robustness. Additionally, the power level of the PDCCH may be adjusted according to channel conditions.

[0059] The approach introduced in LTE is to define a limited set of CCE locations where the PDCCH can be located for each UE. This limited set of CCE locations where a UE can find its PDCCH can be referred to as a search space (SS). In LTE, the search space has different sizes depending on each PDCCH format. Furthermore, UE-specific and common search spaces are defined separately. The UE-specific search space (USS) is configured individually for each UE, while the scope of the common search space (CSS) is known to all UEs. The UE-specific and common search spaces can overlap for a given UE. In cases with a relatively small search space, if some CCE locations in the search space for a specific UE are allocated, there may be no remaining CCEs, and thus, the base station may not be able to find CCE resources to transmit the PDCCH to all possible UEs within a given subframe. To minimize the possibility of blocking like the above continuing to the next subframe, a UE-specific hopping sequence is applied at the start of the UE-specific search space.

[0060] Table 3 shows the sizes of the common and UE-specific search spaces.

[0061] PDCCH formatNumberof CCEs (n)Number of candidates in common search spaceNumberof candidates in dedicated search space01-612-624423822

[0062] To control the computational load associated with the total number of blind decoding (BD) operations, the UE is not required to simultaneously search all defined DCI formats. Typically, within a UE-specific search space, the UE always searches for formats 0 and 1A. Formats 0 and 1A have the same size and are distinguished by flags in the message. Additionally, the UE may be requested to receive additional formats (e.g., 1, 1B, or 2, depending on the PDSCH transmission mode configured by the base station). In a common search space, the UE searches for formats 1A and 1C. Additionally, the UE may be configured to search for formats 3 or 3A. Formats 3 and 3A have the same size as formats 0 and 1A and can be distinguished by scrambling the CRC with different (common) identifiers rather than UE-specific identifiers. The PDSCH transmission techniques and the information contents of the DCI formats according to the transmission mode are listed below.

[0063] Transmission Mode (TM)

[0064] ● Transmission Mode 1: Transmission from a single base station antenna port

[0065] ● Transmission Mode 2: Transmission Diversity

[0066] ● Transmission mode 3: Open-loop spatial multiplexing

[0067] ● Transmission Mode 4: Closed-loop spatial multiplexing

[0068] ● Transmission Mode 5: Multi-User MIMO

[0069] ● Transmission Mode 6: Closed-loop Rank-1 precoding

[0070] ● Transmission Mode 7: Single-antenna port (port 5) transmission

[0071] ● Transmission Mode 8: Dual-layer transmission (ports 7 and 8) or single-antenna port (port 7 or 8) transmission

[0072] ● Transmission Mode 9: Up to 8 layer transmission (ports 7 to 14) or single-antenna port (port 7 or 8) transmission

[0073] DCI format

[0074] ● Format 0: Resource grant for PUSCH transmission (uplink)

[0075] ● Format 1: Resource allocation for single codeword PDSCH transmission (transmission modes 1, 2, and 7)

[0076] ● Format 1A: Compact signaling of resource allocation for single codeword PDSCH (all modes)

[0077] ● Format 1B: Compact resource allocation for PDSCH (mode 6) using rank-1 closed-loop precoding.

[0078] ● Format 1C: Very compact resource allocation for PDSCH (e.g., paging / broadcast system information)

[0079] ● Format 1D: Compact resource allocation for PDSCH (mode 5) using multi-user MIMO

[0080] ● Format 2: Resource allocation for PDSCH (mode 4) in closed-root MIMO operation

[0081] ● Format 2A: Resource allocation for PDSCH (mode 3) in open-loop MIMO operation

[0082] ● Format 3 / 3A: Power control command with 2-bit / 1-bit power adjustment value for PUCCH and PUSCH

[0083] Figure 5 illustrates EPDCCH. EPDCCH is a channel additionally introduced in LTE-A.

[0084] Referring to FIG. 5, a PDCCH (for convenience, Legacy PDCCH, L-PDCCH) according to the existing LTE can be allocated to the control region of a subframe (see FIG. 4). In the drawing, the L-PDCCH region refers to a region to which the L-PDCCH can be allocated. Meanwhile, a PDCCH can be additionally allocated within a data region (e.g., a resource region for a PDSCH). The PDCCH allocated to the data region is referred to as an EPDCCH. As illustrated, by securing additional control channel resources through the EPDCCH, scheduling constraints due to the limited control channel resources of the L-PDCCH region can be alleviated. Similar to the L-PDCCH, the EPDCCH carries DCI. For example, the EPDCCH can carry downlink scheduling information and uplink scheduling information. For example, a terminal can receive an EPDCCH and receive data / control information through a PDSCH corresponding to the EPDCCH. Additionally, the terminal can receive the EPDCCH and transmit data / control information through the PUSCH corresponding to the EPDCCH. Depending on the cell type, the EPDCCH / PDSCH may be allocated starting from the first OFDM symbol of a subframe. Unless otherwise specified, the PDCCH in this specification includes both the L-PDCCH and the EPDCCH.

[0085] Figure 6 illustrates the structure of an uplink subframe used in LTE(-A).

[0086] Referring to Fig. 6, a subframe (500) consists of two 0.5 ms slots (501). Assuming the length of a normal cyclic prefix (CP), each slot consists of seven symbols (502), and one symbol corresponds to one SC-FDMA symbol. A resource block (RB) (503) is a resource allocation unit corresponding to 12 subcarriers in the frequency domain and one slot in the time domain. The structure of an uplink subframe of LTE(-A) is largely divided into a data region (504) and a control region (505). The data region refers to communication resources used in transmitting data such as voice and packets transmitted to each terminal, and includes a PUSCH (Physical Uplink Shared Channel). The control region refers to the communication resources used to transmit uplink control signals, such as downlink channel quality reports from each terminal, reception ACK / NACK for downlink signals, and uplink scheduling requests, and includes the PUCCH (Physical Uplink Control Channel). The Sounding Reference Signal (SRS) is transmitted through the SC-FDMA symbol located at the very end of the time axis in one subframe. SRSs of multiple terminals transmitted in the last SC-FDMA of the same subframe can be distinguished by frequency position / sequence. The SRS is used to transmit the uplink channel status to the base station, and is transmitted periodically according to the subframe period / offset set by the upper layer (e.g., RRC layer), or aperiodically at the request of the base station.

[0087] Figure 7 is a diagram illustrating SC-FDMA and OFDMA methods. The 3GPP system employs OFDMA in the downlink and SC-FDMA in the uplink.

[0088] Referring to FIG. 7, both a terminal for uplink signal transmission and a base station for downlink signal transmission are the same in that they include a serial-to-parallel converter (401), a subcarrier mapper (403), an M-point IDFT module (404), and a CP (Cyclic Prefix) addition module (406). However, a terminal for transmitting a signal in the SC-FDMA method additionally includes an N-point DFT module (402). The N-point DFT module (402) offsets to some extent the IDFT processing influence of the M-point IDFT module (404), thereby allowing a transmission signal to have a single carrier property.

[0089] Next, we'll explain HARQ (Hybrid Automatic Repeat reQuest). In a wireless communication system, when multiple terminals have data to transmit on the uplink / downlink, the base station selects which terminals will transmit data every Transmission Time Interval (TTI) (e.g., a subframe). In multicarrier and similar systems, the base station selects which terminals will transmit data on the uplink / downlink every TTI, and also selects the frequency bands that the terminals will use for data transmission.

[0090] In terms of uplink, terminals transmit reference signals (or pilots) in the uplink, and the base station uses the reference signals transmitted from the terminals to determine the channel status of the terminals and selects the terminals to transmit data in the uplink in each unit frequency band for each TTI. The base station notifies the terminals of these results. That is, the base station transmits an uplink assignment message to the terminals scheduled for uplink in a specific TTI, instructing them to send data using a specific frequency band. The uplink assignment message is also referred to as a UL grant. The terminal transmits data in the uplink according to the uplink assignment message. The uplink assignment message may include terminal ID (UE Identity), RB assignment information, Modulation and Coding Scheme (MCS), Redundancy Version (RV), and New Data Indication (NDI).

[0091] In the case of synchronous HARQ, the retransmission time is systematically agreed upon (e.g., 4 subframes after the NACK is received) (synchronous HARQ). Therefore, the UL grant message that the base station sends to the terminal only needs to be sent during the initial transmission, and subsequent retransmissions are performed by ACK / NACK signals (e.g., PHICH signals). In the case of asynchronous HARQ, since the retransmission time is not agreed upon, the base station must send a retransmission request message to the terminal. In addition, in the case of non-adaptive HARQ, the frequency resources or MCS for retransmission are the same as the previous transmission, and in the case of adaptive HARQ, the frequency resources or MCS for retransmission may be different from the previous transmission. For example, in the case of asynchronous adaptive HARQ, since the frequency resources or MCS for retransmission change for each transmission time, the retransmission request message may include terminal ID, RB allocation information, HARQ process ID / number, RV, and NDI information.

[0092] Figure 8 illustrates an example of UL HARQ operation in an LTE(-A) system. In the LTE(-A) system, the UL HARQ scheme uses synchronous non-adaptive HARQ. When using 8-channel HARQ, HARQ process numbers are given as 0 to 7. One HARQ process operates per TTI (e.g., subframe). Referring to Figure 8, a base station (110) transmits a UL grant to a terminal (120) via a PDCCH (S600). The terminal (120) transmits uplink data to the base station (S110) using the RB and MCS specified by the UL grant 4 subframes later (e.g., subframe 4) from the time of receiving the UL grant (e.g., subframe 0) (S602). The base station (110) decodes the uplink data received from the terminal (120) and then generates an ACK / NACK. If decoding of uplink data fails, the base station (110) transmits a NACK to the terminal (120) (S604). The terminal (120) retransmits the uplink data 4 subframes after receiving the NACK (S606). The initial transmission and retransmission of uplink data are handled by the same HARQ processor (e.g., HARQ process 4). ACK / NACK information can be transmitted via the PHICH.

[0093] Meanwhile, in the LTE(-A) system, the DL HARQ method uses asynchronous adaptive HARQ. Specifically, the base station (110) transmits a DL grant to the terminal (120) through the PDCCH. The terminal (120) receives downlink data from the base station (S110) using the RB and MCS specified by the DL grant at the time of receiving the DL grant (e.g., subframe 0). The terminal (120) decodes the downlink data and generates ACK / NACK. If decoding of the downlink data fails, the terminal (120) transmits a NACK to the base station (110) 4 subframes later (e.g., subframe 4) from the time of receiving the downlink data. Thereafter, the base station (110) transmits a DL grant instructing retransmission of the downlink data to the terminal (120) through the PDCCH at a desired time (e.g., subframe X). The terminal (120) re-receives downlink data from the base station (S110) using the RB and MCS specified by the DL grant at the time of receiving the DL grant (e.g., subframe X).

[0094] The base station / terminal has multiple parallel HARQ processes for DL / UL transmission. These multiple parallel HARQ processes allow DL / UL transmissions to be performed continuously while waiting for HARQ feedback regarding the successful or unsuccessful reception of the previous DL / UL transmission. Each HARQ process is associated with a HARQ buffer in the MAC (Medium Access Control) layer. Each HARQ process manages state variables such as the number of transmissions of MAC Physical Data Blocks (PDUs) in the buffer, HARQ feedback for MAC PDUs in the buffer, and the current redundancy version.

[0095] The HARQ process ensures reliable transmission of data (e.g., transport blocks (TBs)). During channel coding, a transport block can be divided into one or more code blocks (CBs) based on the size of the channel encoder. After channel coding, one or more code blocks are combined to form a codeword (CW) corresponding to the transport block.

[0096] Figure 9 illustrates the processing of a transport block (TB). The process of Figure 9 can be applied to data on the DL-SCH, PCH, and MCH (multicast channel) transport channels. Uplink TB (or data on the uplink transport channel) can also be processed similarly.

[0097] Referring to FIG. 9, the transmitter adds a CRC (e.g., 24-bit) (TB CRC) to the TB for error checking. Thereafter, the transmitter can divide the TB+CRC into multiple code blocks considering the size of the channel encoder. In LTE(-A), the maximum size of a code block is 6144 bits. Therefore, if the TB size is less than or equal to 6144 bits, no code block is formed, and if the TB size is greater than 6144 bits, the TB is divided into 6144-bit units to form multiple code blocks. A CRC (e.g., 24-bit) (CB CRC) is individually added to each code block for error checking. After each code block undergoes channel coding and rate matching, they are combined into one to form a codeword. In LTE(-A), data scheduling and the corresponding HARQ process are performed on a TB basis, and the CB CRC is used to determine early termination of TB decoding.

[0098] The HARQ process involves a soft buffer for a transport block and a soft buffer for a code block at the PHY (Physical) layer. The length K for the r-th code block at the transmission end w = 3K ΠThe circular buffer is created as follows:

[0099]

[0100] N IR bits represent the soft buffer size for the transmission block, and N cb represents the soft buffer size for the r-th code block. N cb is obtained as follows, and C represents the number of code blocks.

[0101]

[0102] N IR is as follows.

[0103]

[0104] Here, N soft represents the total number of soft channel bits according to terminal capability.

[0105] IfN soft = 35982720,K C = 5,

[0106] else ifN soft = 3654144, and if the terminal can support up to two spatial layers for the DL cell, K C = 2

[0107] elseK C = 1

[0108] End if.

[0109] K MIMO is 2 if the terminal is configured to receive PDSCH transmission based on transmission mode 3, 4, 8 or 9, and 1 otherwise.

[0110] M DL_HARQ is the maximum number of DL HARQ processes.

[0111] M limit is 8.

[0112] In FDD and TDD, the terminal is configured to have two or more serving cells, and at least K for each serving cell. MIMO ·min(M DL_HARQ ,M limit ) for a transmission block, if decoding of a code block of a transmission block fails, the terminal shall at least Stores the received soft channel bits corresponding to the range of n SB is given by the following mathematical formula.

[0113]

[0114] w k ,C,N cb ,K MIMO , and M limit is as defined above.

[0115] M DL_HARQ is the maximum number of DL HARQ processes.

[0116] is the number of configured serving cells.

[0117] is the total number of soft channel bits according to terminal capability.

[0118] When deciding k, the terminal prioritizes storing soft channel bits corresponding to lower values ​​of k. k corresponds to the received soft channel bits. Range may contain a subset that is not included in the received soft channel bits.

[0119] In LTE, scheduling for UL transmission is possible only when the UL transmission timing of the terminal is synchronized. The random access process is used for various purposes. For example, random access is performed during network initialization, handover, and data generation. Furthermore, a terminal can acquire UL synchronization through the random access process. Once UL synchronization is obtained, the base station can allocate resources for UL transmission to the terminal. The random access process is divided into a contention-based process and a non-contention-based process.

[0120] Figure 10 illustrates a collision-based random access process.

[0121] Referring to Fig. 10, a terminal receives information about random access from a base station through system information. Thereafter, if random access is required, the terminal transmits a random access preamble (also referred to as message 1) to the base station (S710). When the base station receives the random access preamble from the terminal, the base station transmits a random access response message (also referred to as message 2) to the terminal (S720). Specifically, downlink scheduling information for the random access response message can be CRC-masked with a Random Access-RNTI (RA-RNTI) and transmitted on the L1 / L2 control channel (PDCCH). A terminal that receives a downlink scheduling signal masked with the RA-RNTI can receive and decode a random access response message from the PDSCH. Thereafter, the terminal checks whether the random access response message includes random access response information directed to the terminal. Whether or not there is random access response information directed to the terminal can be checked by whether or not there is a RAID (Random Access Preamble ID) for the preamble transmitted by the terminal. The random access response information includes a Timing Advance (TA) indicating timing offset information for synchronization, radio resource allocation information used for uplink, and a temporary identifier (e.g., T-CRNTI) for terminal identification. When the terminal receives the random access response information, it transmits an uplink message (also referred to as message 3) to the uplink SCH (Shared Channel) according to the radio resource allocation information included in the response information (S730). After receiving the uplink message of step S730 from the terminal, the base station transmits a contention resolution (also referred to as message 4) message to the terminal (S740).

[0122] Figure 11 illustrates a collision-free random access process. A collision-free random access process can be used during a handover process or requested by a base station command. The basic process is identical to the contention-based random access process.

[0123] Referring to Figure 11, the terminal is allocated a random access preamble exclusively for itself (i.e., a dedicated random access preamble) from the base station (S810). The dedicated random access preamble indication information (e.g., a preamble index) can be included in a handover command message or received via the PDCCH. The terminal transmits the dedicated random access preamble to the base station (S820). Thereafter, the terminal receives a random access response from the base station (S830), and the random access process is terminated.

[0124] DCI format 1A is used to initiate a collision-free random access process with a PDCCH order. DCI format 1A is also used for compact scheduling for a single PDSCH codeword. The following information is transmitted using DCI format 1A.

[0125] - Flag for distinguishing DCI format 0 / 1A: 1 bit. Flag value 0 indicates DCI format 0, and flag value 1 indicates DCI format 1A.

[0126] When the CRC of DCI format 1A is scrambled with C-RNTI and all remaining fields are set as follows, DCI format 1A is used for the random access process by PDCCH command.

[0127] - Localized / distributed VRB (Virtual Resource Block) allocation flag: 1 bit. The flag is set to 0.

[0128] - Resource block allocation information: Bit. All bits are set to 1.

[0129] - Preamble index: 6 bits

[0130] - PRACH mask index: 4 bits

[0131] - All remaining bits are set to 0 for compact scheduling of PDSCH codewords in DCI format 1A.

[0132] Figure 12 illustrates a carrier aggregation (CA) communication system.

[0133] Referring to FIG. 12, a plurality of uplink / downlink component carriers (CCs) can be aggregated to support wider uplink / downlink bandwidth. Each CC can be adjacent or non-adjacent in the frequency domain. The bandwidth of each component carrier can be independently determined. Asymmetric carrier aggregation, where the number of UL CCs and the number of DL CCs are different, is also possible. Meanwhile, control information can be configured to be transmitted and received only through a specific CC. This specific CC can be referred to as a primary CC, and the remaining CCs can be referred to as secondary CCs. For example, when cross-carrier scheduling (or cross-CC scheduling) is applied, the PDCCH for downlink allocation can be transmitted on DL CC#0, and the corresponding PDSCH can be transmitted on DL CC#2. The term “component carrier” can be replaced with other equivalent terms (e.g., carrier, cell, etc.).

[0134] For cross-CC scheduling, the carrier indicator field (CIF) is used. The presence or absence of a CIF within a PDCCH can be enabled semi-statically, terminal-specifically (or terminal group-specifically) via higher-layer signaling (e.g., RRC signaling). The basics of PDCCH transmission can be summarized as follows.

[0135] ■ CIF disabled: PDCCH on a DL CC allocates PDSCH resources on the same DL CC and PUSCH resources on a single linked UL CC.

[0136] ● No CIF

[0137] ■ CIF enabled: PDCCH on a DL CC can allocate PDSCH or PUSCH resources on one DL / UL CC among multiple merged DL / UL CCs using CIF.

[0138] ● LTE DCI format extended to include CIF

[0139] - CIF (if set) is a fixed x-bit field (e.g., x=3)

[0140] - CIF (if set) position is fixed regardless of DCI format size

[0141] When a CIF exists, the base station can allocate a monitoring DL CC (set) to reduce BD complexity on the terminal side. For PDSCH / PUSCH scheduling, the terminal can detect / decode PDCCH only on the corresponding DL CC. Furthermore, the base station can transmit PDCCH only through the monitoring DL CC (set). The monitoring DL CC set can be configured in a terminal-specific, terminal-group-specific, or cell-specific manner.

[0142] Figure 13 illustrates scheduling when multiple carriers are merged. Assume that three DL CCs are merged. Assume that DL CC A is configured as a PDCCH CC. DL CCs A through C may be referred to as serving CCs, serving carriers, serving cells, etc. When CIF is disabled, each DL CC can transmit only the PDCCH scheduling its own PDSCH without CIF according to the LTE PDCCH rules (non-cross-CC scheduling). On the other hand, when CIF is enabled by UE-specific (or UE-group-specific or cell-specific) higher layer signaling, a specific CC (e.g., DL CC A) can transmit the PDCCH scheduling the PDSCH of DL CC A as well as the PDCCH scheduling the PDSCH of other CCs using CIF (cross-CC scheduling). On the other hand, PDCCH is not transmitted on DL CC B / C.

[0143] Meanwhile, millimeter wave (mmW) signals have short wavelengths, allowing for multiple antenna installations within the same area. For example, in the 30 GHz band, the wavelength is 1 cm, so a total of 100 antenna elements can be installed in a two-dimensional array with a 0.5 λ (wavelength) spacing on a 5 x 5 cm panel. Therefore, mmW systems often use multiple antenna elements to enhance beamforming (BF) gain, thereby increasing coverage or throughput.

[0144] In this regard, if there is a TXRU (transceiver unit) that allows transmission power and phase control for each antenna element, independent beamforming for each frequency resource is possible. However, it is not practical in terms of cost to install a TXRU for all 100 antenna elements. Therefore, a method of mapping multiple antenna elements to a single TXRU and controlling the direction of the beam with an analog phase shifter is being considered. This analog beamforming method has the disadvantage of being unable to provide frequency-selective beams because it can only create a single beam direction across the entire band. A hybrid BF with B TXRUs, which is an intermediate form of digital BF and analog BF, but has fewer than Q antenna elements, can be considered. In this case, the number of beam directions that can be transmitted simultaneously is limited to B or fewer, although there may be differences depending on the connection method of B TXRUs and Q antenna elements.

[0145] Figure 14 illustrates analog beamforming. Referring to Figure 14, a transmitter can transmit a signal by changing the direction of the beam over time (transmit beamforming), and a receiver can also receive a signal by changing the direction of the beam over time (receive beamforming). Within a certain time period, (i) the transmit beam and the receive beam can change their directions simultaneously over time, (ii) the transmit beam can be fixed while only the direction of the receive beam can change over time, or (iii) the receive beam can be fixed while only the direction of the transmit beam can change over time.

[0146] Meanwhile, self-contained subframes are being considered in next-generation RAT (Radio Access Technology) to minimize data transmission latency. Figure 15 illustrates the structure of a self-contained subframe. In Figure 15, the hatched area represents a DL control region, and the black area represents an UL control region. Unmarked areas can be used for either DL or UL data transmission. Since DL and UL transmissions are performed sequentially within a single subframe, DL data can be sent and UL ACK / NACK can also be received within the subframe. Consequently, the time required for data retransmission when a data transmission error occurs is reduced, thereby minimizing the transmission latency of the final data.

[0147] As examples of configurable / configurable self-contained subframe types, at least the following four subframe types can be considered, each listed in chronological order.

[0148] - DL control interval + DL data interval + GP (Guard Period) + UL control interval

[0149] - DL control section + DL data section

[0150] - DL control section + GP + UL data section + UL control section

[0151] - DL control section + GP + UL data section

[0152] In the DL control period, PDFICH, PHICH, and PDCCH can be transmitted, and in the DL data period, PDSCH can be transmitted. In the UL control period, PUCCH can be transmitted, and in the UL data period, PUSCH can be transmitted. GP provides a time gap when the base station and the terminal switch from transmission mode to reception mode or from reception mode to transmission mode. Some OFDM symbols at the time of switching from DL to UL within a subframe can be set as GP.

[0153] Example

[0154] In the case of the existing LTE system, when the size of DL data (i.e., TBS) exceeds a certain level, the bit stream (i.e., TB) to be transmitted via the PDSCH is divided into multiple CBs, and channel coding and CRC are applied to each CB (see Fig. 9). If the terminal fails to receive (e.g., decode) even one of the multiple CBs included in a TB, it reports the HARQ-ACK feedback corresponding to the corresponding TB to the base station as a NACK. Through this, the base station retransmits all CBs corresponding to the corresponding TB. In other words, the HARQ operation for DL ​​data in the existing LTE(-A) is performed based on TB-based scheduling / transmission from the base station and TB-based HARQ-ACK feedback configuration from the terminal.

[0155] Meanwhile, the next-generation RAT (hereinafter, new RAT) system may fundamentally have a wider system (carrier) BW (bandwidth) than LTE, which is likely to result in a larger (maximum) TBS than in existing LTE. Accordingly, the number of CBs constituting one TB may also be greater than in LTE. Therefore, if HARQ-ACK feedback is performed on a TB basis as in the past in the new RAT system, even if decoding errors (i.e., NACKs) occur for only a small number of CBs, retransmission scheduling on a TB basis may be required, which may reduce resource utilization efficiency. In addition, in the new RAT system, a portion (symbol) of the resources allocated to transmission of delay-insensitive data type 1 (e.g., enhanced Mobile BroadBand, eMBB) with a large time interval (TTI) may be used to transmit delay-sensitive data type 2 (e.g., Ultra-Reliable Low Latency Communications, URLLC) with a small time interval (TTI) by puncturing data type 1. In addition, due to the influence of an interference signal with time-selective characteristics, a phenomenon may occur in which decoding errors (i.e., NACKs) are concentrated only in a specific portion of multiple CBs constituting one TB for data type 1.

[0156] The present invention proposes a method for performing (retransmission) scheduling on a CB or CBG (CG group) basis, taking into account the characteristics of the new RAT system, and configuring / transmitting HARQ-ACK feedback on a CB / CBG basis. Specifically, the present invention proposes a method for configuring a CBG, a method for configuring HARQ-ACK (hereinafter, A / N) feedback, a method for operating a terminal's reception soft buffer, and a method for handling specific mismatch situations.

[0157] For convenience, the proposed methods of the present invention are divided into several embodiments, but this is for convenience of explanation, and these can be used in combination with each other.

[0158] First, the abbreviations / terms used in the present invention are explained.

[0159] - TBS: TB size. The total number of bits that make up a TB.

[0160] - CB: Code Block

[0161] - CB size: total number of bits that make up the CB

[0162] - CBG: Code Block Group. All CBs (constituting a single TB) may be configured as a single CBG, some CBs may be configured as a single CBG, or each CB may be configured as a single CBG.

[0163] - A / N: HARQ-ACK response. That is, it can mean ACK, NACK, and DTX. DTX indicates that the PDCCH is missed. The A / N bit can be set to 1 for ACK and 0 for NACK. It can be used equivalently with HARQ-ACK and ACK / NACK.

[0164] - CBG-based A / N: Since CRC is not added to CBG, A / N for CBG can be generated based on the error check result for CB in CBG. For example, if all CB in CBG are successfully detected, the terminal can set A / N response (or A / N bit) for CBG to ACK, and if any of CB in CBG is not successfully detected, the terminal can set A / N response (or A / N bit) for CBG to ACK (logical AND). A / N payload for CBG(s) of TB includes multiple A / N (response) bits, and each A / N (response) bit corresponds one-to-one to a CBG of TB.

[0165] - CBG-based retransmission: TB retransmission can be performed on a CBG basis in response to CBG-based A / N. For example, when a base station retransmits a TB to a terminal, it can perform retransmission only for the CBG that received a NACK from the terminal. In this case, when retransmitting a TB corresponding to the same HARQ process as the previous transmission of the TB, the CB(s) within the CBG remain the same as when the TB was initially transmitted.

[0166] - CBG size: The number of CBs that make up the CBG

[0167] - CBG Index: An index that distinguishes CBGs. Depending on the context, a CBG index can be used as equivalent to a CBG with that index.

[0168] - Symbol: Unless otherwise specified, may mean an OFDMA symbol or an SC-FDMA symbol.

[0169] - floor(X): floor function. It means the largest integer less than or equal to X.

[0170] - ceiling(X): Rounding function. It means the smallest integer greater than or equal to X.

[0171] - mod(A, B): means the remainder when A is divided by B.

[0172] (X) How to configure CB

[0173] 1) Method X-1: The number of bits Cn that constitute one CB is given, and Cm CBs are constructed based on this.

[0174] The number of bits Cn constituting one CB may be predefined as the same value regardless of the TBS or as different values ​​(e.g., proportional to the TBS) for each TBS, or may be indicated to the UE through semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI). Accordingly, when the total number of bits constituting a TB is Ck, Cm = floor(Ck / Cn) or Cm = ceiling(Ck / Cn) CBs may be configured. In the former case, only one CB may be configured with (Cn + mod(Ck, Cn)) bits, and the remaining (Cm - 1) CBs may each be configured with Cn bits. In the latter case, only one CB may be configured with mod(Ck, Cn) bits, and the remaining (Cm - 1) CBs may each be configured with Cn bits. In the former case, Cn can mean the minimum number of bits that constitute one CB, and in the latter case, Cn can mean the maximum number of bits that constitute one CB.

[0175] Alternatively, a method of evenly allocating bits per CB to all CBs (near-equal) can be applied. For example, in the previous case, when Cm = floor(Ck / Cn) CBs are configured, mod(Ck, Cn) CBs can be configured with (Cn + 1) bits, and the remaining CBs can be configured with Cn bits. Also, when Cm = ceiling(Ck / Cn) CBs are configured, (Cn - mod(Ck, Cn)) CBs can be configured with (Cn - 1) bits, and the remaining CBs can be configured with Cn bits. In the former case, Cn can mean the minimum number of bits that constitute one CB, and in the latter case, Cn can mean the maximum number of bits that constitute one CB, respectively.

[0176] Meanwhile, when the above method is applied, one or more specific CBs (hereinafter, small CBs) among the total Cm CBs may be composed of a smaller number of bits than the remaining other CBs (hereinafter, regular CBs). Therefore, a method of grouping Cm CBs with unequal sizes into M multiple CBGs may be required. Specifically, the cases where the total number of CBs Cm is a multiple of the number of CBGs M and the cases where it is not may be distinguished, and the following CB grouping methods may be considered for each case. In the following, the CBG size may mean the number of CBs per CBG. Meanwhile, when Cm is not a multiple of M, the sizes may differ for each CBG, and the size difference between CBGs may be limited to a maximum of one CB.

[0177] A. If Cm is a multiple of M (all CBGs have the same size)

[0178] - Opt 1-1: Configure small CBs to be distributed across all CBGs as much as possible.

[0179] - Opt 1-2: Configure small CBs to belong to only a small number of CBGs.

[0180] B. If Cm is not a multiple of M (size may vary by CBG)

[0181] - Opt 2-1: Configure it to belong to a large-sized CBG so that it becomes a small CB.

[0182] - Opt 2-2: Configure to belong to a small-sized CBG to become a small CB

[0183] - Opt 2-3: Apply Opt 1-1 or Opt 1-2

[0184] For example, when Cm = 7 and CB indices 1 / 2 / 3 / 4 / 5 / 6 / 7 are composed of 5 / 5 / 5 / 5 / 5 / 5 / 2 bits, respectively, M = 3 CBG configurations can be considered. Here, when Opt 2-1 is applied, CB indices {1, 2}, {3, 4}, {5, 6, 7} can be composed of CBG indices 1 / 2 / 3, respectively, and when Opt 2-2 is applied, CB indices {1, 2, 3}, {4, 5}, {6, 7} can be composed of CBG indices 1 / 2 / 3, respectively. As another example, when Cm = 7 and CB indices 1 / 2 / 3 / 4 / 5 / 6 / 7 are composed of 5 / 5 / 5 / 5 / 4 / 4 / 4 bits, respectively, M = 3 CBG configurations can be considered. Here, when Opt 2-1 is applied, CB indices {1, 2}, {3, 4}, {5, 6, 7} can be composed of CBG indices 1 / 2 / 3, respectively, and when Opt 2-2 is applied, CB indices {1, 2, 3}, {4, 5}, {6, 7} can be composed of CBG indices 1 / 2 / 3, respectively. On the other hand, when Opt 1-1 is applied, CB indices {1, 2, 5}, {3, 6}, {4, 7} can be composed of CBG indices {1, 2}, {3, 4}, {5, 6, 7} can be composed of CBG indices 1 / 2 / 3, respectively, and when Opt 1-2 is applied, CB indices {1, 2}, {3, 4}, {5, 6, 7} can be composed of CBG indices 1 / 2 / 3, respectively.

[0185] Additionally, the size of CBGs with a high probability of retransmission can be reduced as much as possible by including as few CBs as possible in CBGs corresponding to areas where decoding reliability may be low. For example, cases where decoding reliability may be low may include cases where the CB size of the wireless signal is relatively small, the wireless signal is far away in time from the DMRS, the wireless signal is far away from the CSI feedback point, or the wireless signal is mapped to an (OFDMA / SC-FDMA) symbol adjacent to the SRS (or PUCCH or PRACH). To this end, the CBGs can be configured as follows.

[0186] a) Regular CBs are constructed in X-bit units starting from the lower CB index, and small CBs are constructed in Y-bit units starting from a specific CB index (Y < X).

[0187] b) Starting from the CB of the low CB index, regular CBGs are formed by grouping M CBs sequentially, and then small CBGs are formed by grouping K CBs starting from a specific CBG index (K < M). Here, the size difference between CBGs can be limited to a maximum of 1 CB as previously proposed (e.g., M = K + 1). According to a) and b), compared to the CBG of the low index, the CBG of the high index can have a relatively smaller CBG size, and can have more small CBs even if the CBG size is the same.

[0188] c) Map signals sequentially in a frequency-first (or time-first) manner, starting with CBGs with lower CBG indices. Here, CBGs with lower indices can be mapped to resources with relatively higher decoding reliability compared to CBGs with higher indices.

[0189] Meanwhile, in the case where Cn > Ck, all bits of TB are configured as a single CB, and one CB containing Ck bits can be configured.

[0190] 2) Method X-2: The total number of CBs Cm is given, and each CB is configured in units of Cn bits based on this.

[0191] The total number of CBs Cm may be predefined as the same value regardless of the TBS, or as different values ​​(e.g., proportional to the TBS) for each TBS, or may be indicated to the UE via semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI). For example, if the total number of bits constituting the TB is Ck, each CB may be configured with units of Cn = floor(Ck / Cm) or Cn = ceiling(Ck / Cm) bits. In the former case, only one CB may be configured with (Cn + mod(Ck, Cn)) bits, and the remaining (Cm - 1) CBs may each be configured with Cn bits. In the latter case, only one CB may be configured with mod(Ck, Cn) bits, and the remaining (Cm - 1) CBs may each be configured with Cn bits. In the former case, Cn can mean the minimum number of bits that constitute one CB, and in the latter case, Cn can mean the maximum number of bits that constitute one CB.

[0192] Alternatively, a method that evenly allocates bits per CB to all CBs (near-equal) can be applied. For example, in the previous case, if CBs are composed of Cn = floor(Ck / Cm) bit units, mod(Ck, Cm) CBs can be composed of (Cn + 1) (or, ceiling(Ck / Cm)) bits, and the remaining (Cm - mod(Ck, Cm)) CBs can be composed of Cn bits. If CBs are composed of Cn = ceiling(Ck / Cm) bit units, (Cm - mod(Ck, Cm)) CBs can be composed of (Cn - 1) (or, floor(Ck / Cm)) bits, and the remaining mod(Ck, Cm) CBs can be composed of Cn bits. In the former case, Cn can mean the minimum number of bits that constitute one CB, and in the latter case, Cn can mean the maximum number of bits that constitute one CB.

[0193] 3) Method X-3: The minimum number of bits Tm that constitutes one CB is given, and a CB is constructed based on this.

[0194] All CBs constituting a TB can be configured to consist of at least Tm bits. For example, assuming a TBS as Ck, an operation can be considered in which Cm.max, the maximum Cm value that satisfies the relationship Ck / Cm Tm, is calculated, and the TB is divided into Cm.max CBs.

[0195] 4) Method X-4: Scheduling by CB unit and grouping between multiple CBs when the number of CBs is above a certain level

[0196] Only when the total number of CBs K constituting one TB is Ts or more, (retransmission) scheduling can be set / defined to be applied to the TB at the CB or CBG level. In addition, when the total number of CBs K is Tg or more, multiple CBs can be set / defined to be grouped to form one CBG (e.g., Ts < Tg). Here, the number of bits Cn constituting one CB can be defined in advance or given through specific signaling (e.g., RRC signaling, DCI).

[0197] (A) Method of composing CBG

[0198] 1) Method A-1: ​​The number of CBs N that constitute one CBG is given, and M CBGs are constructed based on this.

[0199] The number of CBs N constituting one CBG may be predefined as the same value regardless of the TBS or as different values ​​(e.g., proportional to the TBS) for each TBS, or may be indicated to the UE via semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI). For example, if the total number of CBs constituting the TB is K, M = floor(K / N) or M = ceiling(K / N) CBGs may be configured. In the former case, only one CBG may be configured with (N + mod(K, N)) CBs, and the remaining (M - 1) CBGs may each be configured with N CBs. In the latter case, only one CBG may be configured with mod(K, N) CBs, and the remaining (M - 1) CBGs may each be configured with N CBs. In the former case, N may represent the minimum number of CBs constituting one CBG, and in the latter case, N may represent the maximum number of CBs constituting one CBG. Meanwhile, the terminal can configure and transmit A / N bits for each CBG.

[0200] Alternatively, a method of evenly allocating the number of CBs per CBG to all CBGs (near-equal) can be applied. For example, in the previous case, when M = floor(K / N) CBGs are configured, mod(K, N) CBGs can be configured with (N + 1) CBs, and the remaining CBGs can be configured with N CBs. In addition, when M = ceiling(K / N) CBGs are configured, (N - mod(K, N)) CBGs can be configured with (N - 1) CBs, and the remaining CBGs can be configured with N CBs. In the former case, N can mean the minimum number of CBs that constitute one CBG, and in the latter case, N can mean the maximum number of CBs that constitute one CBG, respectively.

[0201] Meanwhile, when N > K, all CBs constituting TB belong to a single CBG, and one CBG including K CBs can be formed.

[0202] 2) Method A-2: The total number of CBGs M is given, and each CBG is composed of N CB units based on this.

[0203] The total number of CBGs M may be predefined as the same value regardless of the TBS or as different values ​​(e.g., proportional to the TBS) for each TBS, or may be indicated to the UE via semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI). The UE can identify / configure CBGs from CBs in a TB based on the total number of CBGs M. For example, if the total number of CBs constituting the TB is K, each CBG may be configured with N = floor(K / M) or N = ceiling(K / M) CB units. In the former case, only one CBG may be configured with (N + mod(K, N)) CBs, and the remaining (M - 1) CBGs may be configured with N CBs each. In the latter case, only one CBG may be configured with mod(K, N) CBs, and the remaining (M - 1) CBGs may be configured with N CBs each. In the former case, N can mean the minimum number of CBs that constitute one CBG, and in the latter case, N can mean the maximum number of CBs that constitute one CBG. Meanwhile, the terminal can configure and transmit A / N bits for each CBG. For example, the terminal can configure M A / N bits for TB, and each A / N bit can represent the A / N result for the corresponding CBG. .

[0204] Alternatively, a method of evenly allocating the number of CBs per CBG to the entire CBG can be applied. For example, in the case of the previous case, when the CBG configuration is N = floor(K / M) CB units, mod(K, M) CBGs can be composed of (N + 1) (or, ceiling(K / M)) CBs, and the remaining (M - mod(K, M)) CBGs can be composed of N (or floor(K / M)) CBs. In addition, when the CBG configuration is N = ceiling(K / M) CB units, (M - mod(K, M)) CBGs can be composed of (N - 1) (or, floor(K / M)) CBs, and the remaining mod(K, M) CBGs can be composed of N (or ceiling(K / M)) CBs. In the former case, N can mean the minimum number of CBs constituting one CBG, and in the latter case, N can mean the maximum number of CBs constituting one CBG, respectively.

[0205] Meanwhile, if M > K, each CB can become a CBG, so that a total of K CBGs can be configured. In this case, 1) the entire A / N feedback can be configured with M bits, and the (M - K) bits that do not correspond to actual CBGs can be processed as NACK or DTX, or 2) the A / N feedback itself can be configured with only K bits corresponding to actual CBGs.

[0206] Figure 16 illustrates a signal transmission process according to the present invention.

[0207] Referring to FIG. 16, a terminal may receive information about the number M of code block groups per transport block from a base station via a higher layer signal (e.g., an RRC signal) (S1602). Thereafter, the terminal may receive an initial data transmission from the base station (via a PDSCH) (S1604). Here, the data includes a transport block, the transport block includes a plurality of code blocks, and the plurality of code blocks may be divided into one or more code block groups. Here, some of the code block groups may include a ceiling (K / M) number of code blocks, and the remaining code blocks may include a flooring (K / M) number of code blocks. K represents the number of code blocks in the data. Thereafter, the terminal may feed back code block group-based A / N information for the data to the base station (S1606), and the base station may perform data retransmission based on the code block groups (S1608). The A / N information may be transmitted via a PUCCH or a PUSCH. Here, the A / N information includes multiple A / N bits for the data, and each A / N bit can represent a respective A / N response generated for each code block group for the data. The payload size of the A / N information can be maintained the same based on M regardless of the number of code block groups constituting the data.

[0208] 3) Method A-3: CBG construction based on tree (or nested) structure for number of CBGs M and size of CBGs N.

[0209] A CBG can be configured to have a tree structure for the total number of CBGs M (e.g., M1, M2, ...) and CBG sizes N (e.g., N1, N2, ...). In this case, multiple different CBG configurations based on multiple different (M, N) combinations can be configured for one TB (size). For different (M, N) combinations, considering the CBG configurations for the cases (M1, N1) and (M2, N2), if M1 < M2, N1 > N2 can be set. In addition, one CBG for the case (M1, N1) can be configured to include one or more CBGs for the cases (M2, N2). Conversely, one CBG for the case (M2, N2) can be configured to belong to only one specific CBG for the case (M1, N1). In addition, M2 can be set to be a multiple of M1 and / or N1 can be set to be a multiple of N2. M is 2 m (m = 0, 1, ...) can be set. Meanwhile, one (or multiple) of the possible CBG indices based on the indexes for M, N or (M, N) combinations, or all (M, N) combinations, can be indicated to the terminal through semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI). The terminal can configure and transmit A / N bits for each CBG configured corresponding to the index. M and N can be predefined as the same value regardless of TBS, or can be predefined as different values ​​for each TBS (e.g., proportional to TBS).

[0210] For example, assuming the total number of CBs constituting the TB to be K = 16, and indexing each CB as k = 0, 1, ..., 15, we can consider a method of setting the number of CBGs to M = {1, 2, 4, 8, 16} and setting the corresponding CBG sizes to N = K / M = {16, 8, 4, 2, 1} (nested CBG example 1).

[0211] a) If (M, N) = (1, 16), only one CBG is formed and that CBG contains all 16 CBs.

[0212] b) When (M, N) = (2, 8), two CBGs are formed, and each CBG contains eight different CBs. In this case, one CBG contains two CBGs when (M, N) = (4, 4).

[0213] c) When (M, N) = (4, 4), four CBGs are formed, and each CBG contains four different CBs. In this case, one CBG contains two CBGs when (M, N) = (8, 2).

[0214] d) If (M, N) = (8, 2), 8 CBGs are formed and each CBG contains 2 different CBs.

[0215] e) If (M, N) = (16, 1), 16 CBGs are formed and each CBG contains only one different CB.

[0216] As in the above example, in a state where multiple different (M, N) combinations and the number / size of CBGs according to them are configured / specified in advance, one (or multiple) of the indices of a specific M, N or (M, N) combination, or one (or multiple) of the possible CBG indices based on all (M, N) combinations can be indicated to the terminal. In the above example, there are a total of 5 possible M, N or (M, N) combinations, and the possible CBG indices for all (M, N) combinations are set to a total of 31 (corresponding to the sum of the possible M values ​​{1, 2, 4, 8, 16}). The terminal can perform decoding and corresponding A / N feedback configuration / transmission assuming a CBG configuration corresponding to the M and / or N index for scheduled DL data (e.g., TB or CBG).

[0217] By generalizing this method, for the CBG configurations in the cases of (M1, N1) and (M2, N2) which are different (M, N) combinations, multiple CBG configurations can be set for one TB (size) only under the condition that N1 N2 is set if M1 < M2. For example, assuming that the total number of CBs constituting the TB is K = 6, and each CB is indexed as k = 0, 1, ..., 5, the number of CBGs is set as M = {1, 2, 3, 6}, and the corresponding CBG sizes are set as N = K / M = {6, 3, 2, 1} (nested CBG example 2).

[0218] a) If (M, N) = (1, 6), only one CBG is formed and that CBG contains all six CBs.

[0219] b) If (M, N) = (2, 3), two CBGs are formed, and each CBG contains three different CBs. For example, the CB index sets {0, 1, 2} and {3, 4, 5} each form one CBG.

[0220] c) If (M, N) = (3, 2), three CBGs are formed, and each CBG contains two different CBs. For example, the CB index sets {0, 1}, {2, 3}, and {4, 5} each form one CBG.

[0221] d) If (M, N) = (6, 1), 6 CBGs are formed and each CBG contains only 1 different CB.

[0222] As another example, we can consider a method in which the total number of CBs constituting the TB is assumed to be K = 9, and each CB is indexed as k = 0, 1, ..., 8, the number of CBGs is set to M = {1, 2, 3, 6}, and the corresponding CBG sizes are set to N = {9, (5 or 4), 3, (2 or 1)} (nested CBG example 3).

[0223] a) If (M, N) = (1, 9), only one CBG is formed and that CBG contains all nine CBs.

[0224] b) If (M, N) = (2, 5, or 4), then two CBGs are formed, one containing five CBs and the other containing four CBs. For example, the CB indices sets {0, 1, 2, 3, 4} and {5, 6, 7, 8} each form one CBG.

[0225] c) If (M, N) = (3, 3), three CBGs are formed, and each CBG contains three different CBs. For example, the CB index sets {0, 1, 2}, {3, 4, 5}, and {6, 7, 8} each form one CBG.

[0226] d) If (M, N) = (6, 2, or 1), a total of 6 CBGs are formed, 3 of which contain 2 CBs, and the other 3 contain 1 CB. For example, the CB index sets {0, 1}, {2, 3}, {4, 5}, {6}, {7}, {8} each form one CBG.

[0227] For nested CBG example 2 / 3, a total of 12 (=1+2+3+6) CBGs can be indexed (based on four different (M, N) combinations). Based on this, the base station can indicate (via DCI) the CBGs to be retransmitted and / or the terminal can construct and transmit A / N feedback for the indicated CBGs.

[0228] Meanwhile, considering the DCI overhead for the scheduling target CBG instruction and / or the UCI overhead for the corresponding A / N feedback configuration, the total number of CBG indices L configured in a nested form may be set to be the same for each TBS, or the L value for each TBS may be set such that the bit overhead for the CBG instruction is the same for each TBS (e.g., the ceiling(log2(L)) value is the same).

[0229] 4) Method A-4: CBs belonging to a specific number of symbol sets (and a specific number of RB sets) are organized into one CBG.

[0230] When the time interval (and / or frequency domain) in which a TB is transmitted is divided into multiple symbol sets (hereinafter, Symbol Groups, SG) (and / or multiple RB sets (hereinafter, RB Groups, RBG)), CBs transmitted through each SG (and / or each RBG) may be configured as one CBG. In this case, information about the number of symbols in each SG or the number of symbols constituting a single SG (and / or the number of RBs in each RBG or the number of RBs constituting a single RBG) may be indicated to the UE through semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI). When receiving DL data, the UE may configure and transmit an A / N bit for each CBG.

[0231] Also, it is possible to configure CBGs to have a tree structure like Method A-3 for the number of symbols constituting one SG or the total number of SGs configured within a TB transmission time interval (and / or the number of RBs constituting one RBG or the total number of RBGs configured within a TB transmission frequency region). For example, based on nested CBG example 1 / 2 / 3, assuming that the total number of symbols (or RBs) constituting a TB is K = 16, 6, or 9, each symbol (or RB) can be indexed as k = 0 to 15, k = 0 to 5, or k = 0 to 8. In this state, multiple SGs (or RBGs) having a nested structural relationship with each other can be configured in a form similar to nested CBG example 1 / 2 / 3. In addition, the SG (and / or RBG) size / number can be predefined as the same value regardless of the TBS, or can be predefined as different values ​​for each TB (e.g., proportional to the TBS).

[0232] Meanwhile, when a single CB is mapped / transmitted across multiple SGs (and / or RBGs), the CB may be defined as being included in the CBG corresponding to the SG (and / or RBG) with the lowest or highest symbol index, Opt 1) or the SG (and / or RBG) with the lowest or highest RB index, or Opt 2) the CBG corresponding to the SG (and / or RBG) that contains the most coded bits of the CB.

[0233] Alternatively, if a single CB is mapped / transmitted across multiple SGs (and / or RBGs), from the perspective of CBG configuration / indication for (retransmission) scheduling at the base station, the CB may be configured to be included in all of the multiple CBGs corresponding to the multiple SGs ( / RBGs). On the other hand, from the perspective of configuring A / N feedback per CBG at the terminal, the CB may be included in only a CBG corresponding to a specific one of the multiple SGs ( / RBGs), and the A / N bit may be configured and transmitted for each CBG. In this case, the terminal may select a specific CBG that includes the CB (when configuring A / N feedback) as follows.

[0234] 1) If the decoding result of the CB is NACK, if there is a CBG that includes a CB that is NACK even after excluding the CB (from all multiple CBGs including the CB from a scheduling perspective), one of them (based on the application of Opt 1 / 2) is selected, and if no such CBG exists, one of all multiple CBGs (based on the application of Opt 1 / 2) that includes the CB from a scheduling perspective can be selected.

[0235] 2) Even if the decoding result of the corresponding CB is ACK, one of all multiple CBGs (including the corresponding CB from a scheduling perspective) can be selected (based on the application of Opt 1 / 2).

[0236] Meanwhile, when multiple CBGs containing the same CB are scheduled simultaneously, the CB can be configured to be transmitted only once. For example, the CB can be transmitted in a form that is included in only one of the multiple CBGs (based on the application of Opt 1 / 2).

[0237] By generalizing the above method, the proposed method can be applied when, from the perspective of CBG configuration / instruction for scheduling of the base station, one CB is set to be commonly included in multiple CBGs, and when the terminal operates to include the CB in only a specific one of the multiple CBGs from the perspective of configuring A / N feedback per CBG. For example, when configuring a total of K CBs with M CBGs, all CBGs can be set to include the same number of CBs per CBG, N = ceiling (K / M). In this case, some of the M CBGs can be set to include a specific CB in common. For example, within a set of CBGs smaller than M, any two CBGs can include one CB in common, and the number of CBs commonly included in any two CBGs can be (M - mod (K, M)).

[0238] Alternatively, to prevent a single CB from being mapped / transmitted across multiple SGs (and / or RBGs), or to make the number of data bits belonging to each CBG as identical as possible among the CBGs, the following method can be considered. Assuming a scheduled TBS as A bits and the number of SGs or RBGs (generally CBGs) allocated to the TBS as M, first, (A / M) or ceiling(A / M) or floor(A / M) data bits can be allocated to each CBG. Next, multiple CBs belonging to each CBG can be configured by applying Method X-1 / 2 / 3, with the number of data bits allocated to each CBG replaced by the number of bits Ck corresponding to the TBS in Method X-1 / 2 / 3. Meanwhile, the coded bits for a single CBG can only be mapped / transmitted to one SG or RBG.

[0239] Meanwhile, it is also possible to change the number of symbols constituting one SG according to the number of symbols and / or the number of RBs (or TBS) allocated to data transmission. For example, (to make the number of CBGs as identical as possible) the number of symbols allocated to data transmission may be configured to be larger, the number of symbols per SG may be configured to be larger. Also, (to make the CBG sizes as identical as possible) the number of RBs (or TBS) allocated to data transmission may be configured to be smaller, the number of symbols per SG may be configured to be smaller. Similarly, it is also possible to change the number of RBs constituting one RBG according to the number of RBs and / or the number of symbols (or TBS) allocated to data transmission. For example, (to make the number of CBGs as identical as possible) the number of RBs per RBG may be configured to be larger, the number of RBs per RBG may be configured to be larger, the number of symbols (or TBS) allocated to data transmission may be configured to be smaller, the number of RBs per RBG may be configured to be larger, the number of symbols (or TBS) allocated to data transmission may be larger, the number of RBs per RBG may be configured to be smaller, the number of CBG sizes may be configured to be larger.

[0240] 5) Method A-5: Configure the total number of CBGs M and the CBG size N by TBS.

[0241] The (M, N) combination for CBG configuration can be set (differently) for each TBS. The number of DCI bits for CBG indication and / or the UCI payload size for the corresponding A / N feedback configuration during data scheduling can be determined based on the maximum value M.max among the M values ​​set for each TBS. For example, the CBG indication information and / or A / N payload size can be set to M.max, ceiling(M.max / K), or ceiling(log2(M.max)) bits. Here, K can be a positive integer, for example, K = 2.

[0242] Additionally, if a set of (M, N) combinations to be applied to each TBS is called a TBS-CBG table, then a method may be considered in which multiple TBS-CBG tables are defined / set in advance and one of the multiple TBS-CBG tables is indicated to the UE through semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI). In this case, the (M, N) combinations corresponding to the same TBS may be configured differently among the multiple TBS-CBG tables. Accordingly, the UE may refer to the indicated TBS-CBG table to determine the (M, N) combination corresponding to the indicated TBS through DL / UL scheduling DCI, and perform DL / UL data transmission / reception and A / N feedback transmission based on the determined (M, N) combination.

[0243] Alternatively, the entire TBS set may be divided into multiple TBS ranges, and different CBG configuration methods may be applied to each TBS range. For example, TBS range 1 may be configured with different CBG counts M (or the same CBG size N) for each TBS range, using method A-1, while TBS range 2 may be configured with the same CBG count M for each TBS, using method A-2. In this case, considering DCI overhead and / or UCI payload, TBS range 2 may be configured with TBSs that are larger than those in TBS range 1. Alternatively, the same CBG configuration (e.g., number / size of CBGs) may be applied to each TBS range, but different CBG counts / sizes, etc. may be configured between the TBS ranges. For example, the same number of CBGs M may be configured for each TBS range 1 / 2, using method A-2, or for each TBS, but different M values ​​may be set between TBS ranges 1 and 2. In this case, M of TBS range 2 may be set to a value greater than M of TBS range 1. As another example, for each of TBS ranges 1 / 2, the CBG size N may be configured identically by method A-1 or TBS, but different N values ​​may be set between TBS ranges 1 and 2. In this case, N of TBS range 2 may be set to a value greater than N of TBS range 1.

[0244] 6) Method A-6: Apply interleaving between CBs belonging to the same CBG before data-to-resource mapping.

[0245] Considering the impact of interference with specific (e.g., time-selective) patterns (e.g., URLLC puncturing operation), inter-CB interleaving may be applied between multiple CBs (coded bits) belonging to the same CBG prior to data-to-resource (e.g., RE) mapping. For example, for multiple CBs (coded bits) belonging to a single CBG, 1) intra-CB interleaving may be applied first within each CB, and then inter-CB interleaving may be applied additionally, or 2) (when a CBG-based HARQ operation is configured) only inter-CB interleaving may be applied while omitting intra-CB interleaving. Here, data-to-resource mapping includes RE mapping based on a frequency-first manner, for example.

[0246] In all the above proposed methods, M, N, and K can be set / indicated to the same value for different TBSs, or to different values ​​for different TBSs, or to the same value for some (e.g., N) and different values ​​for the rest (e.g., M, K) depending on the TBS. In addition, considering the way in which one DL data scheduling / transmission is performed across multiple slots, in the above proposed methods, one symbol set (SG) can be configured / configured based on the slot (in this case, the symbol index is applied by replacing the slot index).

[0247] (B) HARQ-ACK feedback method

[0248] 1) Method B-1: Configure / transmit feedback with the (minimum) range containing all NACKs on the CBG index.

[0249] Given a CBG configuration scheme (e.g., number / size of CBGs), considering decoding errors (i.e., NACKs) across consecutive CBG indices due to time-selective interference, the UE may 1) feed back to the base station the CBG index that is the first NACK and the CBG index that is the last NACK (in terms of CBG index), or 2) feed back the CBG index that is the first NACK and the distance between the first NACK and the last NACK. Here, 1) and 2) may be signaled using the Resource Indication Value (RIV) indication scheme applicable to UL resource allocation type 0 or the combinatorial index scheme applicable to UL resource allocation type 1. In this case, the CBG configuration scheme may include Method A-1 / 2 / 3 / 4.

[0250] Additionally, it is also possible for the terminal to directly select one of multiple CBG configuration methods (e.g., number / size of CBGs), and based on the selected CBG configuration, 1) determine the (minimum) CBG range including NACK as described above and feed back the corresponding NACK CBG range and the selected CBG configuration information to the base station, or 2) configure individual A / N bits for each CBG and feed back the information about the selected CBG configuration to the base station. In this case as well, the CBG configuration method may include methods A-1 / 2 / 3 / 4.

[0251] Additionally, the above method can also be applied to CBG scheduling from a base station. Specifically, 1) the first and last CBG indices at which (re)transmission is to be performed, or 2) the first CBG index and the total number of CBGs L to be (re)transmitted can be indicated via DL data scheduling DCI. In this case, the terminal can operate (receiving) under the assumption / consideration that 1) a set of CBGs corresponding to indices between the first and last CBG indices and therebetween, or 2) a set of CBGs corresponding to the first CBG index and L consecutive indices thereafter are scheduled.

[0252] 2) Method B-2: Feedback of the (minimum size) CBG containing all NACKs in the CBG configuration of the tree structure.

[0253] Given a plurality of CBG configurations (e.g., (M, N) combinations) based on a tree structure such as in Method A-3, a terminal may operate to select one specific CBG configuration, determine a CBG index including all NACKs based on the selected CBG configuration, and feed back the NACK CBG index and the selected CBG configuration information together to the base station. Here, it may be desirable that the NACK CBG be selected as a single CBG that includes all NACKs and has a minimum size. In other words, the terminal may operate to first select a specific CBG configuration among multiple CBG configurations having a tree structure such that a single CBG includes all NACKs with a minimum size, and then determine one CBG index including all NACKs based on the selected CBG configuration, and feed back this (together with the selected CBG configuration information) to the base station.

[0254] Also, similarly, given multiple CBG configurations (based on different SG( / RBG) sizes / numbers) having a SG (and / or RBG)-based tree structure as in Method A-4, it is also possible for the terminal to select one CBG configuration based on a specific SG( / RBG), determine a CBG index including all NACKs based on the selected CBG configuration, and feed back the NACK CBG index and the selected CBG configuration (or the corresponding SB( / RBG) configuration) information to the base station together.

[0255] Additionally, the above method can also be applied to CBG scheduling from a base station. Specifically, given multiple CBG configurations (e.g., M and / or N (combinations), or SG ( / RBG) sizes / numbers) having a tree structure similar to Method A-3 or A-4, a CBG index based on a specific CBG configuration can be indicated via DL data scheduling DCI. In this case, the terminal can operate (receive) under the assumption / consideration that a CBG set belonging to the corresponding CBG index has been scheduled via the corresponding DCI.

[0256] 3) Method B-3: Keeping the CBG configuration and corresponding A / N configuration the same during one HARQ process.

[0257] In order to avoid unnecessary RLC level DL data retransmission due to A / N error of a specific CBG, the CBG configuration (for retransmission (CBG) scheduling (instruction) at the base station) and the A / N feedback configuration corresponding to the CBG configuration may be kept the same while one HARQ process is being performed (i.e., until it is terminated). Specifically, the CBG configuration and the corresponding A / N feedback configuration initially applied / instructed for DL ​​data scheduling / transmission with a specific HARQ process ID may be kept the same until the termination of the corresponding HARQ process (e.g., until decoding is successful for all CBs constituting a TB of DL data, or until a new DL data scheduling (with NDI toggled) is started with the same HARQ process ID). Here, the initially applied / indicated CBG and A / N configuration information can be indicated to the UE through semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., DCI, (initial) DL data scheduling DCI). If the initially applied / indicated CBG and A / N configuration information is indicated through semi-static signaling (e.g., RRC signaling), the CBG and A / N configuration information is statically fixed and can be maintained the same in all HARQ processes until a new RRC signaling occurs.

[0258] Meanwhile, the terminal can configure and feed back A / N bits for each CBG, and can operate to feed back NACK for each CBG until decoding is successful (regardless of whether the CBG is scheduled or not), and can operate to feed back ACK for the CBG from the time of successful decoding (regardless of whether the CBG is scheduled or not, and until the corresponding HARQ process ends).

[0259] Figure 17 illustrates a signal transmission process according to the present invention. Figure 17 assumes that the number of CBGs per TB is set to 3, and that the TB is (re)transmitted for the same HARQ process (i.e., assuming operation before the HARQ process corresponding to the TB is terminated).

[0260] Referring to FIG. 17, the terminal can receive CBG #0, #2 for TB (e.g., HARQ process #a) from the base station (S1702). Here, the TB of step S1702 may be an initial transmission or a retransmission corresponding to HARQ process #a. In addition, it is assumed that CBG #1 has never been successfully decoded before. In this case, the terminal transmits A / N information corresponding to three CBGs to the base station (S1704), and sets the A / N information for CBG #1 to NACK, and sets the A / N information for CBG #0, #2 to ACK or NACK depending on the decoding result. Thereafter, the base station retransmits the TB (e.g., HARQ process #a) in units of CBGs, and the terminal can receive CBG #1, #2 for the corresponding TB (S1706). In this case, the terminal transmits A / N information corresponding to three CBGs to the base station (S1708). Since CBG #0 was previously successfully decoded, the A / N information for CBG #0 is set to ACK, and the A / N information for CBG #1 and #2 is set to ACK or NACK depending on the decoding result.

[0261] 4) Method B-4: Set the corresponding A / N transmission time delay differently depending on the number of scheduled CB / CBGs.

[0262] Depending on the number of CBs or CBGs simultaneously scheduled for the same TB (size), the corresponding A / N transmission time delay (i.e., the time interval between DL data reception and the corresponding A / N feedback transmission) can be set differently. Specifically, the smaller the number of scheduled CBs or CBGs, the smaller the corresponding A / N delay can be set. For example, the corresponding A / N delay can be set smaller when some CBs or CBGs are scheduled compared to the case where the entire TB, i.e., all CBs, are scheduled. In addition, assuming the same CBG size, the corresponding A / N delay can be set smaller when a smaller number of CBGs are scheduled. In addition, when the number of scheduled CBGs is the same, the corresponding A / N delay can be set smaller when the CBG size is configured to be smaller.

[0263] 5) Method B-5: Set the CBG configuration (number / size of CBG) differently between DL data scheduling and A / N feedback.

[0264] The CBG configuration (e.g., number / size of CBGs) applied to DL data scheduling / transmission and the CBG configuration applied to A / N feedback corresponding to the reception of the corresponding DL data can be set differently. Here, the CBG configuration can be indicated through DL data scheduling DCI. Specifically, the (M, N) combination for DL ​​data scheduling and the (M, N) combination for A / N feedback configuration can be set to different values. For example, the (M1, N1) combination can be set for DL ​​data scheduling, and the (M2, N2) combination can be set for A / N feedback. Accordingly, when comparing case 1 where M1 > M2 (and N1 < N2) is set and case 2 where M1 < M2 (and N1 > N2), case 1 may increase the number of DCI bits while reducing the number of retransmission DL data resources and A / N feedback bits, and case 2 may decrease the number of DCI bits while increasing the number of retransmission DL data resources and A / N feedback bits.

[0265] 6) Method B-6: Set the A / N transmission time delay differently for each CBG for scheduled multiple CBGs.

[0266] For multiple CBGs scheduled simultaneously, the A / N transmission time delay can be set differently for each CBG (i.e., the A / N for each CBG is transmitted by TDM). Specifically, the A / N delay corresponding to a CBG transmitted through a lower symbol (or slot) index can be set smaller. Through this, the A / N corresponding to a CBG transmitted through a lower symbol (or slot) index can be fed back through a relatively faster symbol (or slot) timing.

[0267] 7) Method B-7: A / N feedback configuration corresponding to (re)transmission scheduling in TB units (consisting of M CBGs)

[0268] The UE may be instructed via semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., (initial) DL data scheduling DCI) whether to perform A / N feedback in a TB-based A / N bit configuration or a CBG-based A / N bit configuration. In the case of CBG-based A / N bit configuration, the A / N payload size (and the PUCCH format for the corresponding A / N transmission) may be configured via semi-static signaling (e.g., RRC signaling). In this case, the total number of CBGs constituting a TB may be determined according to a given (fixed) A / N payload size (e.g., M bits). For example, the number of CBGs may be determined to be M, which is the same as the number of A / N bits. Accordingly, the number of CBGs constituting a TB may be set to be the same for different TBSs, and the number of CBs constituting one CBG may be set differently (e.g., to a value proportional to the TBS) depending on the TBS. Meanwhile, if the total number of CBs composing the TB is equal to or smaller than the given A / N payload size, the entire A / N feedback can be configured by allocating A / N bits to each CB without grouping the CBs. On the other hand, if the total number of CBs N is smaller than the given A / N payload size M (bits), the A / N bits can be allocated to each CB, but 1) the remaining (M - N) bits not allocated to A / N per CB can be processed as NACK, or 2) the A / N payload size itself can be changed to N (bits) equal to the total number of CBs.

[0269] Meanwhile, for each TBS, the number of CBs constituting the TB and the CBG configuration based thereon (e.g., the total number of CBGs constituting the TB M, the number of CBs constituting a single CBG N) may be determined according to predetermined rules. In addition, the A / N payload size and the corresponding PUCCH format may be configured based on the number of CBGs configured in the TB. For example, the PUCCH format and the candidate PUCCH resource set used for CBG-based A / N transmission may be independently (differently) configured for each TBS (and thus the total number of CBGs M). In addition, the M value and / or the corresponding PUCCH format may be indicated to the UE through semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., (DL data scheduling) DCI). For example, a combination of multiple (M values, PUCCH formats (and candidate PUCCH resource sets)) may be pre-specified, and a specific combination may be indicated via DCI, or the M value and PUCCH format may be independently indicated via RRC and / or DCI. Meanwhile, when an M value is indicated, a PUCCH format (and candidate PUCCH resource set) pre-specified for the corresponding M value may be automatically determined, or when a PUCCH format is indicated, a pre-specified M value for the corresponding PUCCH format may be automatically determined.

[0270] Alternatively, the N value and / or the corresponding PUCCH format may be indicated to the UE via semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., (DL data scheduling) DCI). For example, a plurality of combinations of N values ​​and corresponding (M, PUCCH formats (and candidate PUCCH resource sets)) may be pre-specified, and then a specific combination may be indicated via DCI, or the N value and the PUCCH format may be independently indicated via RRC signaling and / or DCI. Meanwhile, when the N value is indicated, the PUCCH format (and candidate PUCCH resource set) specified for the corresponding M value may be automatically determined, or when the PUCCH format is indicated, the total number of CBGs and the number of CBs per CBG may be automatically determined based on the A / N payload size (e.g., M bits) thereof.

[0271] 8) Method B-8: Configuring A / N feedback corresponding to some CBG (re)transmissions (among the M CBGs constituting TB)

[0272] When scheduling (re)transmission for L or fewer CBGs (L < M) out of the total M CBGs that constitute TB, the following method can be considered.

[0273] Opt 1) The same A / N payload size (e.g., M bits) as in the case of A / N feedback corresponding to TB unit (re)transmission (as in Method B-7) may be applied. Accordingly, the actual A / N is mapped only to L bits (corresponding to CBGs scheduled for retransmission), and the remaining (M - L) bits (corresponding to CBGs that are not scheduled) may be mapped to ACK or NACK, or processed as NACK, depending on the decoding success / failure of the corresponding CBG (as in Method B-3). Opt 2) A different (e.g., smaller) A / N payload size (and PUCCH format) as in the case of A / N feedback corresponding to TB unit (re)transmission may be applied. In the case of Opt 2, the A / N payload size (and PUCCH format) may be changed according to the number of scheduled CBGs L. For example, the A / N payload may consist of only L bits.

[0274] Here, L can be semi-fixed to a single value through semi-static signaling (e.g., RRC signaling) or dynamically changed through dynamic signaling (e.g., DL data scheduling DCI). In the former case, corresponding CBG indication signaling can be configured to enable scheduling for up to L CBGs out of the total M CBGs through CBG-by-CBG scheduling DCI. In addition, retransmission scheduling (from the base station) can be performed only for L CBGs (L < M) or fewer out of the total M CBGs constituting the TB. In this case, if the number of CBGs to be scheduled exceeds L, the base station / terminal can perform scheduling (DCI transmission) / A / N feedback on a TB-by-TB basis.

[0275] Meanwhile, Opt 1 and Opt 2 can be applied assuming that the CBG configuration initially applied / instructed for TB scheduling / transmission (e.g., the total number of CBGs constituting the TB, M, and the number of CBs constituting a single CBG, N) remains the same during the HARQ process.

[0276] Additionally, for Opt 1, the A / N payload size is set based on TB unit (re)transmission (e.g., M bits), but in order to configure A / N feedback only for the actually scheduled CBGs, the CBs belonging to the entire scheduled L CBGs (each consisting of N CBs) are reconfigured into M CBGs (consisting of a number of CBs less than N), and the entire A / N feedback can be configured according to the A / N bit allocation per CBG based on this. In this case, the base station can also perform retransmission scheduling by assuming the M CBGs corresponding to the A / N feedback as the entire CBG set. Meanwhile, in a situation where a CB regrouping process is involved at a terminal corresponding to a DL data receiver or an A / N transmitter, if a NACK-to-ACK error occurs, a mismatch (resulting in performance degradation) in the CBG configuration between the terminal and the base station may occur. Considering these issues, in addition to the A / N information for each M CBG, the entire A / N feedback (payload) can be configured by including an indicator (e.g., 1 bit) for indicating the presence or absence of a NACK feedback per TB or a retransmission request for the entire TB. Based on this, the terminal can map / transmit the indicator to a state corresponding to "TB NACK" or "TB retransmission request" when a CBG configuration mismatch occurs. The base station receiving this can then perform TB scheduling based on the initial CBG configuration before regrouping.

[0277] Meanwhile, in the case of CBG retransmission scheduling DCI corresponding to A / N feedback in Opt 2, corresponding signaling can be configured in the form of 1) retransmission CBG indication based on the total number of CBGs M regardless of changes in A / N payload size, and 2) CBG indication under the assumption that the set of CBGs (M or less) fed back by the terminal with NACK is the entire CBG configuration.

[0278] Additionally, it is also possible to instruct the UE through semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., (DL data scheduling) DCI) whether to always apply the same A / N payload size (and PUCCH format) regardless of the number of scheduled CBGs, as in Opt 1, or to (dynamically) change the A / N payload size (and PUCCH format) according to the number of scheduled CBGs, as in Opt 2.

[0279] 9) Method B-9: A / N feedback per CBG only if some of the M CBGs that make up TB are NACKs.

[0280] Only when the number of CBGs that are NACKs among the total M CBGs that constitute TB is L (L < M) or less, CBG-level A / N feedback can be configured / transmitted (e.g., individual A / N bits are allocated to each CBG). On the other hand, when the number of CBGs that are NACKs exceeds L, TB-level A / N feedback can be configured / transmitted. In this case, since CBG-level A / N feedback is configured only for L or fewer NACKs, the retransmission CBG (index) indication through the CBG-level (retransmission) scheduling DCI can be 1) in the form of an indication for L or fewer CBGs among the total M, or 2) signaling corresponding to the form of a CBG indication can be configured assuming that the set of CBGs (L or less) that the UE fed back as NACKs constitutes the entire CBG configuration. For example, when i = {1, ..., L}, for all values ​​of i, all combinations of selecting i CBGs out of the total M CBGs are indexed, and the terminal can feed back one of those indices to the base station to indicate the set of CBGs that are NACKs.

[0281] 10) Method B-10: CBG retransmission scheduling and A / N feedback in a form where the maximum number of CBGs is limited to M.

[0282] From a base station scheduling perspective, the entire CBG configuration can be configured with Mr CBGs (Mr M), and the UE can be instructed to retransmit L CBGs among them (L Mr). Here, M has a fixed value for at least one TB transmission or one HARQ process, while Mr (and L) can change at each (retransmission) scheduling point.

[0283] In this case, the terminal can operate as follows from the A / N feedback perspective.

[0284] Opt 1) A / N feedback can be configured based on the maximum possible number of CBGs M. For example, the total A / N payload size can be configured as M bits, but (M - L) bits corresponding to actual unscheduled CBGs can be processed as NACK or DTX.

[0285] Opt 2) A / N feedback can be configured based on the total number of CBGs, Mr, at the scheduling point. For example, the total A / N payload size can be configured as Mr bits, but (Mr - L) bits corresponding to CBGs that are not actually scheduled can be processed as NACK or DTX.

[0286] Opt 3) A / N feedback can be configured based on the number of scheduled CBGs L. For example, the total A / N payload size can be configured as L bits, and A / N bits can be mapped / transmitted for each scheduled CBG.

[0287] For Opt 2 / 3, the A / N payload size can be changed depending on the Mr value or L value, and accordingly, the PUCCH format (and candidate PUCCH resource set) used for A / N feedback transmission can also be changed.

[0288] Furthermore, in this case, the entire Mr CBG configuration for retransmission scheduling at the base station can be configured for the entire set of CBs constituting the TB (i.e., the entire set of CBGs is the same as the entire TB), or can be configured limited to a specific portion of the entire CBs (i.e., the entire set of CBGs corresponds to a portion of the TB). In the former case, the Mr value at a specific scheduling point in time for one TB transmission or one HARQ process can be restricted to always be set to a value less than or equal to the Mr value at the previous scheduling point in time. In the latter case, the specific portion of CBs can mean 1) a CB set belonging to the L CBGs scheduled at the previous scheduling point in time, or 2) a CB set belonging to a CBG that has been fed back with a NACK from the terminal among the L scheduled CBGs.

[0289] 11) Method B-11: Handling of (subsequent) CBGs scheduled for retransmission prior to A / N feedback transmission

[0290] A situation may arise where a CBG retransmission (hereinafter, subsequentCBG) for the same TB is scheduled prior to the transmission of the A / N feedback (hereinafter, first A / N) corresponding to the reception of a specific TB (hereinafter, original TB). In this case, the operation of transmitting the A / N feedback reflecting the reception combining for the subsequentCBG through the first A / N time point may be impossible because the decoding completion time point for the subsequentCBG is too late. Here, the reception combining may mean the operation of emptying (flushing) the buffer where the previously received signal is stored and then storing the subsequent CBG. In this case, the terminal may 1) transmit the A / N feedback according to the decoding result only for the original TB at the first A / N time point and perform reception combining for the subsequent CBG (for the A / N feedback at a later time point), or 2) transmit the A / N feedback according to the decoding result reflecting the reception combining of the subsequentCBG at a time point later by a specific delay than the first A / N time point. 2) In case of first A / N, A / N transmission may be omitted (dropped) or only A / N for original TB may be transmitted.

[0291] Meanwhile, in a UL data scheduling situation, similarly to the above, (subsequent) CBG retransmission for the same TB may be scheduled at a point in time prior to transmission of a specific (or, initial) TB. Here, the original TB transmission point in time (hereinafter, TX timing 1) and the subsequent CBG transmission point in time (hereinafter, TX timing 2) may be different from each other, and TX timing 2 may be indicated as a point in time later than TX timing 1. In this case, the terminal may transmit only the remaining signals after excluding the CBG corresponding to the subsequent CBG from among the scheduled original TB signals (e.g., puncturing the RE / RB / symbol to which the corresponding CBG is mapped) through TX timing 1, and may transmit the subsequent CBG scheduled for retransmission as is through TX timing 2.

[0292] In addition, in a cross-slot scheduling situation for DL ​​data, similarly to the above, (subsequent) CBG retransmission for the same TB can be scheduled at a time point before a specific (or initial) TB reception. Here, the original TB reception time point (hereinafter, TX timing 1) and the subsequent CBG reception time point (hereinafter, TX timing 2) can be different from each other, and TX timing 2 can be indicated as a time point later than TX timing 1. In this case, the terminal can receive only the remaining signals after excluding the CBG corresponding to the subsequent CBG from the scheduled original TB signal (e.g., puncturing the RE / RB / symbol to which the corresponding CBG is mapped) through TX timing 1, and can receive the subsequent CBG scheduled for retransmission as is through TX timing 2.

[0293] (C) Soft buffer operation method

[0294] 1) Method C-1: Determine the minimum buffer size per CB based on the total number of CBs belonging to the NACK CBG.

[0295] For a (minimum) buffer size Bt per TB allocated to a HARQ process or a TB, a method may be considered to determine the minimum buffer size per CB from the perspective of terminal reception, which is the buffer size Bc divided by the sum of the number of CBs belonging to the CBG(s) fed back by the terminal (to the base station) with NACKs Cn (e.g., Bc = Bt / Cn). Specifically, one may consider replacing C with Cn in Equation 4 as follows. Here, the minimum buffer size per CB may mean, for example, the minimum number of (soft channel) bits that the terminal should store in the buffer for each CB for TB transmission.

[0296]

[0297] In this case, compared to the existing method based on A / N feedback in TB units, there is an advantage of increasing the minimum buffer size per CB (e.g., since C > Cn). In addition, Cn applied to one HARQ process or one TB transmission can be determined 1) based only on the first A / N feedback (of which CBG is NACK) composed of CBG units (i.e., Cn is applied equally until the end of the HARQ process), or 2) based on the A / N feedback (of which CBG is NACK) at each point in time for each A / N transmission (i.e., Cn is determined according to the NACK CBG at each scheduling / feedback point in time).

[0298] Meanwhile, a method of applying Cn of method C-2 to mathematical expression 5 (i.e., the total number of CBs belonging to CBG(s) that have been fed back as NACK or require retransmission (or have not received ACK feedback) from the base station's perspective) can also be considered.

[0299] 2) Method C-2: Rate-matching operation at the base station (limited / circular buffer) for retransmitted CBG signals

[0300] When rate-matching (limited / cyclic buffer) is performed based on the total number of CBGs fed back as NACKs (from terminals) or requiring retransmission from the base station perspective, an A / N error may cause a mismatch between the NACK CBGs from the base station perspective and the NACK CBGs fed back by the terminal. To eliminate this mismatch, the following actions can be considered.

[0301] 1) The base station always operates to perform retransmission scheduling simultaneously / all at once for all CBGs that have been fed back as NACK (or, have not received ACK feedback) (i.e., it does not allow retransmission scheduling for only some NACK CBGs) (the terminal operates under the assumption / consideration of this), or

[0302] 2) (Allowing the base station to schedule retransmission for only a portion of the entire NACK CBGs) From the base station's perspective, it is possible to consider an operation of indicating to the terminal through DL data scheduling DCI the entire CBG information (e.g., the number / index of NACK CBGs) that has been fed back as NACK or requires retransmission (or for which ACK feedback has not been received).

[0303] Even in this case, the minimum buffer size per TB Bt allocated to one HARQ process or one TB can be determined as the minimum buffer size per CB from the perspective of base station transmission, which is the buffer size Bc, which is calculated by dividing the total number of CBs belonging to CBG(s) that have been fed back with NACK or require retransmission (or have not received ACK feedback) from the perspective of base station (e.g., Bc = Bt / Cn). Specifically, it is possible to consider replacing C with Cn in Equation 2 as follows.

[0304]

[0305] Even in this case, compared to the existing method that only applies TB unit retransmission, there is an advantage of being able to increase the minimum buffer size per CB (e.g., since C > Cn). Cn applied to one TB transmission can be 1) determined based on the time point of the first CBG unit retransmission performed (i.e., Cn is applied equally until the end of the HARQ process), or 2) determined for each CBG unit retransmission time point (i.e., Cn is determined based on the number of CBGs that have been fed back with NACK or require retransmission (or, have not received ACK feedback) at each time point).

[0306] Meanwhile, if the indication information for the CBG index to be (re)transmitted and the buffer flush indication information for each CBG are signaled through the data scheduling DCI, the signaling of the buffer flush indication information may not be necessary for the CBG index without the (re)transmission indication. Here, the buffer flush information may include the indication information on whether to flush the buffer to empty the received CBG signal before storing it in the buffer, or to combine it with the previously stored CBG signal without emptying it. If the buffer is flushed to empty the buffer for the CBG index without the (re)transmission indication (or conversely, the buffer is combined without emptying it) the terminal may operate under the condition that the CBG index is regarded / assumed as a CBG for which an ACK feedback has been received from the base station or for which retransmission is not required. Conversely, if the terminal is instructed to combine without emptying the buffer (or conversely, to empty the buffer by flushing it), the terminal may perform no action for that CBG index (and its corresponding receive buffer).

[0307] 3) Method C-3: Applying power offset to A / N feedback PUCCH transmission according to CBG unit scheduling

[0308] The power offset added / applied to PUCCH transmission carrying A / N feedback composed of CBG units can be determined as a value proportional to the values ​​of Opt 1 / 2 / 3 / 4 / 5 / 6 / 7. Accordingly, the larger the number of CBGs in Opt 1 / 2 / 3 / 4 / 5 / 6 / 7, the larger the power offset can be added / applied.

[0309] Opt 1) Total number of CBGs to which A / N bits are allocated or which are subject to A / N feedback (without distinction between A / N)

[0310] Opt 2) Number of CBGs scheduled from the base station

[0311] Opt 3) Number of NACK CBGs (from the base station) indicated by the base station in method C-2

[0312] Opt 4) Number of NACK CBGs at the terminal

[0313] Opt 5) Considering the A / N feedback configuration method such as Method B-3, the sum of the number of CBGs in Opt 2 and the number of CBGs that were not scheduled but were fed back as ACKs

[0314] Opt 6) The sum of the number of CBGs in Opt 3 and the number of CBGs that were not scheduled but were fed back with ACK.

[0315] Opt 7) The number of CBGs excluding CBGs that have already fed back ACK at a point in time before the timing, with the power offset added / applied to the A / N PUCCH transmission through a specific timing.

[0316] (D) How to handle mismatch

[0317] 1) Method D-1: Mismatch between A / N information per CBG fed back by the terminal and CBG scheduled for retransmission from the base station

[0318] A discrepancy (due to an A / N error) may occur between the CBG-specific A / N information fed back by the terminal and the corresponding CBG index scheduled for retransmission from the base station. For example, the CBG index scheduled by the base station may not include some CBGs that the terminal fed back with a NACK, and / or may include CBGs that the terminal has already fed back with an ACK. In this case, the terminal may be configured to perform the following actions.

[0319] Opt 1) For CBGs that were previously fed back with NACK among scheduled CBGs, map the A / N results decoded after combining, or

[0320] Opt 2) For the CBGs that were previously fed back as ACKs among the scheduled CBGs, re-map the ACKs (omitting combining / decoding) (see Method B-3).

[0321] Opt 3) Map NACKs to all CBGs, or

[0322] Opt 4) Perform NACK feedback in TB units or retransmission request for the entire TB, or

[0323] Opt 5) It can operate to discard the corresponding CBG scheduling DCI.

[0324] Meanwhile, if the scheduled CBG contains all the CBGs that were previously fed back with NACK, it is also possible to apply one of Opt 1 / 2, and if not, to apply one of Opt 3 / 4 / 5.

[0325] 2) Method D-2: Mismatch between the CRC applied to the entire TB and the CRC applied to the CB unit and / or CBG unit.

[0326] The CRC check results (e.g., pass / fail) received at the terminal may differ between the CRC applied to the entire TB, the CRC applied to each CB, and the CRC applied to each CBG. Here, a pass CRC check result means that the corresponding data block was successfully / correctly detected, and a fail CRC check result means that the corresponding data block was not successfully / correctly detected.

[0327] For example, the CRC check results of CB and / or CBG units may all pass (i.e., the CB CRC-based CRC check passes), while the CRC check result of the entire TB may fail (i.e., the TB CRC-based CRC check fails). Conversely, the CRC check result of at least one CB and / or CBG unit may fail (i.e., the CB CRC-based CRC check fails), while the CRC check result of the entire TB may pass (i.e., the TB CRC-based CRC check passes). In this case, the terminal may apply one of Opt 3 / 4 / 5 of Method D-1. Opt 3 / 4 / 5 of Method D-1 is as follows.

[0328] Opt 3) Map NACKs to all CBGs, or

[0329] Opt 4) Perform NACK feedback in TB units or retransmission request for the entire TB, or

[0330] Opt 5) The corresponding CBG scheduling DCI can be discarded.

[0331] As another example, the CRC check results of all CB units within a specific CBG may all pass, while the CRC check result of the entire CBG may fail. Conversely, the CRC check result of the entire CBG may pass even though the CRC check result of at least one CB unit within the specific CBG fails. In this case, the terminal may map the CBG to a NACK and provide feedback, or apply one of the methods Opt 3 / 4 / 5 of Method D-1.

[0332] (E) CBG scheduling DCI configuration

[0333] 1) Method E-1: RV configuration and setup in CBG unit scheduling (DCI)

[0334] In the (retransmission) scheduling DCI of the CBG unit, the RV field can be configured as follows: 1) only one with the same size as the RV field of the TB unit scheduling DCI, and the indicated RV value can be applied equally to all scheduled CBGs (in this case, the number of RV values ​​can be configured the same as in the case of the TB unit scheduling), or 2) an individual RV field can be configured for each CBG, but each size can be configured to be smaller than the RV field of the TB unit scheduling DCI (however, the number of RV values ​​can be configured to be smaller than in the case of the TB unit scheduling).

[0335] 2) Method E-2: Perform retransmission scheduling for some CBGs (among the M CBGs that make up TB)

[0336] It can be operated so that retransmission scheduling is possible only for up to L CBGs (L < M) out of the total M CBGs that constitute a TB. Here, L can be indicated as a single value to the terminal through semi-static signaling (e.g., RRC signaling). Accordingly, up to L CBGs out of the total M CBGs can be indicated through CBG-by-Channel Scheduling DCI from the base station, and for retransmission scheduling for CBGs exceeding L, TB-by-TB scheduling DCI (or a flag indicating TB-by-TB (re)transmission scheduling within the DCI) can be applied. Specifically, when i = {1, ..., L}, all combinations for selecting i CBGs out of the total M CBGs can be indexed, and a method can be considered in which a CBG set / combination corresponding to one of the indices is indicated to the terminal through the CBG retransmission scheduling DCI.

[0337] 3) Method E-3: Use of NDI field in CBG unit scheduling (DCI)

[0338] The NDI field can be interpreted differently depending on whether it is a (re)transmission for the entire TB or a retransmission for some CBGs (out of all CBGs constituting the TB). For example, a combination in which all CBGs constituting the TB are instructed to be transmitted via DCI and the NDI bit is toggled at the same time can be recognized as scheduling for new data transmission. Accordingly, a case in which only some of the entire CBGs are instructed to be transmitted via DCI can be considered a retransmission (not new data), and the NDI field can be used for other specific purposes. Alternatively, an indicator indicating whether the transmission is for the entire TB or for some CBGs can be directly signaled via DCI. In this case, a combination in which the transmission of the entire TB is instructed and the NDI bit is toggled at the same time can be recognized as scheduling for new data transmission. Accordingly, the latter case (i.e., an indication of transmission of some CBGs) can be considered a retransmission, and the NDI field can be used for other specific purposes. Meanwhile, when the NDI field is used for other specific purposes, the NDI field may 1) indicate whether to store the received CBG signal by combining it with the previously stored signal in the receive buffer corresponding to the corresponding CBG index, or to flush and empty the previously stored signal and newly store only the received CBG signal (i.e., CBG bufferflush indicator, CBGFI), or 2) indicate the CBG (index) to be (re)transmitted (i.e., CBG transmission indicator, CBGTI).

[0339] 4) Method E-4: Use of the Buffer Flush Indicator Field in CBG Unit Scheduling (DCI)

[0340] The buffer flush indicator field can be interpreted differently for data retransmission (without NDI toggling) and new data transmission (with NDI toggling). For example, in the case of data retransmission, it can be used to indicate whether to flush the buffer (for each CBG) before storing the received CBG signals in the buffer or to combine them without emptying them, as is the original purpose of the buffer flush indicator. On the other hand, in the case of new data transmission, since the buffer flush operation is basically assumed before storing the received signals, the buffer flush indicator can be used for other specific purposes. When the buffer flush indicator field is used for other specific purposes, the buffer flush indicator field can include bits indicating TBS and / or MCS information of the data being scheduled. Conversely, the TBS / MCS field can include TBS / MCS information in the DCI scheduling the new data transmission, while it can include bits constituting the buffer flush indicator in the DCI scheduling the data retransmission.

[0341] 5) Method E-5: Use of CBGTI (and CBGFI) fields in CBG-based scheduling (DCI)

[0342] Based on the value indicated through the CBGTI field in the DCI (or a combination of the values ​​indicated through the CBGFI field), a buffer flush for a specific CBG (set) can be indicated. First, each bit constituting the CBGTI field can be used to individually indicate whether or not to (re)transmit each CBG index. For example, bit "1" can indicate that the CBG (corresponding to the bit) is (re)transmitted, and bit "0" can indicate that the CBG is not (re)transmitted. Meanwhile, the CBGFI field / bit can be used to indicate whether or not to flush the buffer for the CBG for which (re)transmission is indicated through the CBGTI field. For example, bit "1" can indicate to flush the buffer (for the CBG for which (re)transmission is indicated), and bit "0" can indicate not to flush the buffer.

[0343] First, in a state where only the CBGTI field is configured / set (without configuring a separate CBGFI field) within the DCI (hereinafter, CBG mode 1), all bits constituting the CBGTI field may be indicated as "0" (without the NDI toggled). In this case, the terminal may define / consider that (re)transmission for all CBGs constituting the given TB is indicated and, at the same time, a buffer flush operation for all CBGs is indicated. Accordingly, the terminal may operate to store a newly received CBG signal in the buffer after flushing a signal previously stored in the buffer. Meanwhile, in CBG mode 1 (without the NDI toggled), all bits constituting the CBGTI field may be indicated as "1". In this case, the terminal may define / consider that (re)transmission for all CBGs constituting the given TB is indicated without a buffer flush operation being indicated.

[0344] Next, in a state where both the CBGTI field and the CBGFI field are configured / set within the DCI (hereinafter, CBG mode 2), all bits constituting the CBGTI field (without toggling the NDI) may be indicated as "0". In this case, (the terminal) may determine / consider that (re)transmission for all CBGs constituting the given TB is indicated. In addition, in this state, in case 1) when the CBGFI bit is indicated as "0", (the terminal) may determine / consider that a buffer flush operation for a specific portion of CBGs (hereinafter, CBG sub-group 1) is indicated, and in case 2) when the CBGFI bit is indicated as "1", (the terminal) may determine / consider that a buffer flush operation for another specific portion of CBGs (hereinafter, CBG sub-group 2) is indicated. CBG(s) belonging to CBG sub-group1 and CBG sub-group2 may be configured to be completely exclusive of each other (with the union of the corresponding CBGs being the entire CBG set) or partially identical. Meanwhile, in CBG mode 2, when all bits constituting the CBGTI field are indicated as "1" and the CBGFI bit is indicated as "1" (or "0") (while the NDI is not toggled), (the terminal) may specify / consider that (re)transmission is indicated for all CBGs constituting the given TB and that a buffer flush operation for all CBGs is indicated (or not indicated).

[0345] Meanwhile, considering early termination of the TB decoding operation at the terminal, 1) decoding is performed sequentially for each CB in turn for multiple CBGs (e.g., decoding is performed in the order of CB1 in CBG-1 => CB1 in CBG-2 => ... CB1 in CBG-M => CB2 in CBG-1 => ...), or 2) decoding is performed sequentially for each CBG (in terms of index) for each CBG (e.g., decoding is performed in the order of CBs in CBG-1 => CBs in CBG-2 => ...), and when a CBG that is a NACK occurs, a NACK can be fed back (omitting the decoding operation) for all subsequent CBGs (indices).

[0346] Meanwhile, for DL / UL data transmitted based on the SPS method, the CBG-based retransmission scheduling and CBG-specific A / N feedback configuration operations may not be applied / configured. Accordingly, the CBG-based retransmission scheduling and CBG-specific A / N feedback configuration operations may be applied / configured only for general scheduling-based DL / UL data transmission rather than the SPS method, and the TB-based scheduling and TB-specific (i.e., TB-level) A / N feedback operations (e.g., configuring / transmitting 1-bit A / N for one TB) may be applied / configured for SPS-based DL / UL data transmission. In addition, the CBG-based retransmission scheduling and the CBG-specific A / N feedback configuration operations may not be applied / configured for DL / UL data (and / or Msg3 scheduled from RAR accompanying the random access process and Msg4 transmitted for the purpose of contention resolution) scheduled through terminal (group) CSS-based DCI transmission (or a specific DCI format, for example, a TM-common DCI format similar to DCI format 0 / 1A in LTE (commonly set / used for different TMs)). Accordingly, the CBG-based retransmission scheduling and the CBG-specific A / N feedback configuration operations may be applied / configured only for DL / UL data transmission scheduled through USS-based DCI transmission rather than CSS (or a TM-only DCI format set / used only for a specific TM). On the other hand, DL / UL data (and / or Msg3 / 4) transmissions scheduled via CSS-based DCI (or TM-common DCI format) transmissions may have TB-based scheduling and TB-by-TB (TB-level) A / N feedback behavior applied / configured (i.e., configuring TB-level A / N feedback).

[0347] Meanwhile, in a situation where CBG-based retransmission scheduling and CBG-specific A / N feedback configuration operations are set, when TB-level A / N feedback is configured for the above reasons (or for other reasons, for example, when the UE bundles A / Ns per CBG to reduce A / N payload, or when the A / N bundling operation is instructed by the base station), the A / N method may differ depending on whether (case 1) only A / N for a single TB is transmitted without multiplexing, or (case 2) multiple A / Ns for multiple TBs are transmitted by multiplexing. For example, in case 1, only a 1-bit A / N payload may be configured, and then A / N may be transmitted using a PUCCH format / resource that supports a small payload (e.g., up to 2 bits). On the other hand, in case 2, when the number of CBGs per TB is set to N, Opt 1) A / N for TB can be mapped to the corresponding N bits in the same repeated manner, or Opt 2) A / N for TB can be mapped to 1 bit corresponding to a specific (e.g., lowest) CBG index. Meanwhile, Opt 1) and Opt 2) can be applied regardless of Case 2 in a situation where CBG-based retransmission scheduling and CBG-specific A / N feedback configuration operations are set.

[0348] For Case 2, the terminal can transmit A / N using a PUCCH format / resource that supports large payloads (e.g., 3 bits or more) by configuring a multi-bit A / N payload including N-bit A / N corresponding to the corresponding TB. The multi-bit A / N payload can include A / N information corresponding to multiple TBs. For example, the multi-bit A / N payload can include multiple N-bit A / N corresponding to multiple TBs.

[0349] Meanwhile, considering a situation where the above-described intentional URLLC puncturing operation is applied in a co-channel inter-cell environment, it may be desirable to minimize the interference effect of URLLC signals transmitted in at least a specific cell on DMRS signals used for DL / UL data reception in other cells. To this end, an operation of mutually transmitting / exchanging symbol position information to be used for DMRS transmission in each cell and / or symbol position information to be used for URLLC (puncturing) transmission in each cell may be considered between cells.

[0350] The proposed methods of the present invention may not be limited to DL data scheduling and transmission situations, and may be applied equally / similarly to UL data scheduling and transmission situations (e.g., CB / CBG configuration according to TB, UL data transmission timing setting, CBG scheduling DCI configuration, etc.). In this regard, in the proposed method of the present invention, DL data (scheduling DCI) may be replaced with UL data (scheduling DCI).

[0351] Figure 18 illustrates a base station and a terminal applicable to the present invention.

[0352] Referring to FIG. 18, the wireless communication system includes a base station (BS, 110) and a terminal (UE, 120). If the wireless communication system includes a relay, the base station or the terminal may be replaced with the relay.

[0353] The base station (110) includes a processor (112), a memory (114), and a radio frequency (RF) unit (116). The processor (112) may be configured to implement the procedures and / or methods proposed in the present invention. The memory (114) is connected to the processor (112) and stores various information related to the operation of the processor (112). The RF unit (116) is connected to the processor (112) and transmits and / or receives a radio signal. The terminal (120) includes a processor (122), a memory (124), and a radio frequency unit (126). The processor (122) may be configured to implement the procedures and / or methods proposed in the present invention. The memory (124) is connected to the processor (122) and stores various information related to the operation of the processor (122). The RF unit (126) is connected to the processor (122) and transmits and / or receives a radio signal.

[0354] The embodiments described above are combinations of components and features of the present invention in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form an embodiment of the present invention by combining some components and / or features. The order of operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form an embodiment or may be incorporated as a new claim through a post-application amendment.

[0355] In this document, embodiments of the present invention have been described primarily focusing on the signal transmission and reception relationship between a terminal and a base station. This transmission and reception relationship is equally / similarly extended to signal transmission and reception between a terminal and a relay or a base station and a relay. Certain operations described as being performed by a base station in this document may, in some cases, be performed by its upper node. That is, it is obvious that various operations performed for communication with a terminal in a network composed of multiple network nodes including a base station may be performed by the base station or other network nodes other than the base station. The base station may be replaced by terms such as fixed station, Node B, eNode B (eNB), and access point. In addition, the terminal may be replaced by terms such as UE (User Equipment), MS (Mobile Station), MSS (Mobile Subscriber Station).

[0356] Embodiments of the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0357] When implemented via firmware or software, an embodiment of the present invention may be implemented in the form of modules, procedures, functions, etc. that perform the functions or operations described above. The software code may be stored in a memory unit and executed by a processor. The memory unit may be located within or outside the processor and may exchange data with the processor via various known means.

[0358] It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the scope of the invention. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present invention are intended to be included within the scope of the present invention.

[0359] The present invention can be used in a terminal, base station, or other equipment of a wireless mobile communication system.

Claims

1. In a method for transmitting HARQ-ACK (Hybrid ARQ Acknowledgement) information based on CBG (Code Block Group) by a communication device in a wireless communication system, A step of performing decoding on CBGs constituting TB (Transport Block); After the above decoding, the step of re-receiving the TB; and A step of transmitting a plurality of HARQ-ACK bits for re-reception of the above TB, wherein each HARQ-ACK bit represents a HARQ-ACK response for each CBG of the TB, A method in which, among the plurality of HARQ-ACK bits, the HARQ-ACK bit for the first CBG that has been successfully decoded before re-reception of the TB is mapped to ACK regardless of whether the first CBG is received or not when re-receiving the TB.

2. In paragraph 1, A method wherein the first CBG includes a CBG that was not received when the TB is re-received.

3. In paragraph 1, A method in which, among the above plurality of HARQ-ACK bits, the HARQ-ACK bit for the second CBG that is not received during re-reception of the TB and is not successfully decoded before re-reception of the TB is mapped to NACK (Negative ACK).

4. In paragraph 1, A method in which each CBG includes one or more CBs, each CB is appended with a CB-based CRC (Cyclic Redundancy Check), and the TB is appended with a TB-based CRC.

5. In paragraph 1, A method in which the total number M of CBGs constituting the above TB is received through RRC (Radio Resource Control) signaling, and the number of the plurality of HARQ-ACK bits is M.

6. In paragraph 1, A method in which the TB of the above decoding process and the TB of the above re-receiving process share the same HARQ process.

7. In paragraph 1, The above wireless communication system is 3GPP (3 rd A method comprising a wireless communication system based on the Generation Partnership Project (GPP).

8. In a communication device used to transmit HARQ-ACK (Hybrid ARQ Acknowledgement) information based on CBG (Code Block Group) in a wireless communication system, RF(Radio Frequency) module; and comprising a processor, said processor comprising: Decoding is performed on the CBGs that make up the TB (Transport Block), After the above decoding, the TB is re-received, Transmitting multiple HARQ-ACK bits for re-reception of the above TB, each HARQ-ACK bit being configured to indicate a HARQ-ACK response for each CBG of the above TB, A communication device in which, among the plurality of HARQ-ACK bits, the HARQ-ACK bit for the first CBG that has been successfully decoded before re-reception of the TB is mapped to ACK regardless of whether the first CBG is received or not when re-receiving the TB.

9. In paragraph 8, A communication device wherein the first CBG includes a CBG that was not received when the TB is re-received.

10. In paragraph 8, A communication device in which, among the plurality of HARQ-ACK bits, the HARQ-ACK bit for the second CBG that is not received during re-reception of the TB and is not successfully decoded before re-reception of the TB is mapped to NACK (Negative ACK).

11. In paragraph 8, A communication device, wherein each CBG includes one or more CBs, each CB has a CB-based CRC (Cyclic Redundancy Check) appended to it, and each TB has a TB-based CRC appended to it.

12. In paragraph 8, A communication device in which the total number M of CBGs constituting the above TB is received through RRC (Radio Resource Control) signaling, and the plurality of HARQ-ACK bits are M.

13. In paragraph 8, A communication device in which the TB of the above decoding process and the TB of the above re-receiving process share the same HARQ process.

14. In paragraph 8, The above wireless communication system is 3GPP (3 rd A communication device including a wireless communication system based on the Generation Partnership Project (GPP).

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