WO2018164495A1 - Method and apparatus for transmitting and receiving wireless signal in wireless communication system - Google Patents

Abstract

The present invention relates to a wireless communication system and, particularly, to a method comprising: a step of decoding CBGs forming a TB; a step of re-receiving the TB after the decoding; and a step of transmitting a plurality of HARQ-ACK bits for the re-receiving of the TB, each HARQ-ACK bit representing a HARQ-ACK response to each CBG of the TB, wherein a HARQ-ACK bit for a first CBG, which was successfully decoded prior to the re-receiving of the TB among the plurality of HARQ-ACK bits, is mapped to an ACK regardless of whether the first CBG is received during the re-receiving of the TB; and to an apparatus therefor.

Description

Method and apparatus for transmitting and receiving wireless signal in wireless communication system

The present invention relates to a wireless communication system, and more particularly to a method and apparatus for transmitting and receiving wireless signals. The wireless communication system includes a carrier aggregation (CA) -based wireless communication system.

Wireless communication systems are widely deployed to provide various kinds of communication services such as voice and data. In general, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single carrier frequency (SC-FDMA). division multiple access) system.

An object of the present invention is to provide a method and an apparatus therefor for efficiently performing a wireless signal transmission and reception process.

Technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In one aspect of the present invention, in a method for transmitting control information by a terminal in a wireless communication system, receiving information on the number M of code block groups defined for one transport block from a base station through a higher layer signal; ; Receiving a first transport 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 about the first transport block to the base station, wherein each code block includes a code block-based cyclic redundancy check (CRC). Is added, and 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. A method is provided.

In another aspect of the present invention, a terminal used in a wireless communication system, the terminal comprising: a radio frequency (RF) 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 a higher layer signal, and to receive a first transport block including a plurality of code blocks. Receiving from the base station through a physical layer channel and transmitting a HARQ-ACK payload including HARQ-ACK (Hybrid ARQ Acknowledgement) information about the first transport block to the base station, wherein each code block includes a code block -Cyclic Redundancy Check (CRC) is added, a transport block-based CRC is added to the first transport block, and the HARQ-ACK payload is a plurality of M code block groups corresponding to the first transport block. A terminal including the HARQ-ACK bit is provided.

Preferably, the upper layer signal may include a Radio Resource Control (RRC) signal, and the physical layer channel may include a physical downlink shared channel (PDSCH).

Preferably, the size of the HARQ-ACK payload may remain the same based on M during the HARQ process for the first transport block.

Preferably, when the first transport block is composed of a plurality of code block groups, some of the plurality of code block groups include ceiling (K / M) code blocks, and the rest of the plurality of code block groups It includes flooring (K / M) code blocks, the ceiling is a rounding function, the flooring is a rounding function, K can represent the number of code blocks in the first transport block.

Preferably, when a code block group is configured for the first transport block, each HARQ-ACK bit in the HARQ-ACK payload is each HARQ-ACK information generated in code block group units for the first transport block. Can be represented.

Preferably, when no code block group is set for the first transport block, a plurality of HARQ-ACK bits for the first transport block in the HARQ-ACK payload have the same value, and the first Each HARQ-ACK bit for the transport block may represent HARQ-ACK information generated in transport block group units for the first transport block.

Preferably, if the code block group-based CRC check results are all successful for the first transport block, but the transport block-based CRC check result is a failure, the first transport block in the HARQ-ACK payload. The plurality of HARQ-ACK bits for may indicate NACK (Negative Acknowledgment).

In another aspect of the present invention, a method for receiving control information by a base station in a wireless communication system, comprising: transmitting information about the number M of code block groups defined for one transport block to a user equipment through a higher layer signal; step; Transmitting a first transport block including a plurality of code blocks to the terminal through a physical layer channel; And receiving a HARQ-ACK payload including HARQ-ACK (Hybrid ARQ Acknowledgement) information about the first transport block from the terminal, wherein each code block includes a code block-based cyclic redundancy check (CRC). Is added, and 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. A method is provided.

In another aspect of the present invention, a base station used in a wireless communication system, the base station comprising: a radio frequency (RF) module; And a processor, wherein the processor transmits information about the number M of code block groups defined for one transport block to an MS through a higher layer signal, and transmits a first transport block including a plurality of code blocks. A HARQ-ACK payload is transmitted to the UE through a physical layer channel, and includes a HARQ-ACK payload including HARQ-ACK (Hybrid ARQ Acknowledgement) information about the first transport block from the MS. -Cyclic Redundancy Check (CRC) is added, a transport block-based CRC is added to the first transport block, and the HARQ-ACK payload is a plurality of M code block groups corresponding to the first transport block. A terminal including the HARQ-ACK bit is provided.

According to the present invention, it is possible to efficiently transmit and receive wireless signals in a wireless communication system.

Effects obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description in order to provide a thorough understanding of the present invention, provide an embodiment of the present invention and together with the description, illustrate the technical idea of the present invention.

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 same.

2 illustrates a structure of a radio frame.

3 illustrates a resource grid of a downlink slot.

4 shows a structure of a downlink subframe.

5 illustrates an Enhanced Physical Downlink Control Channel (EPDCCH).

6 illustrates a structure of an uplink subframe used in LTE (-A).

FIG. 7 illustrates a Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme and an Orthogonal Frequency Division Multiple Access (OFDMA) scheme.

8 illustrates UL ULQ (Uplink Hybrid Automatic Repeat reQuest) operation.

9 illustrates a transport block (TB) process.

10 to 11 illustrate a random access procedure.

12 illustrates a Carrier Aggregation (CA) communication system.

13 illustrates cross-carrier scheduling.

14 illustrates analog beamforming.

15 illustrates the structure of a self-contained subframe.

16-17 illustrate signal transmission according to the present invention.

18 illustrates a base station and a terminal that can be applied to the present invention.

The following techniques include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like. It can be used in various radio access systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) long term evolution (LTE) is part of Evolved UMTS (E-UMTS) using E-UTRA and LTE-A (Advanced) is an evolved version of 3GPP LTE. For clarity, the following description focuses on 3GPP LTE / LTE-A, but the technical spirit of the present invention is not limited thereto.

In a wireless communication system, a terminal receives information through a downlink (DL) from a base station, and the terminal transmits information through an uplink (UL) to the base station. The information transmitted and received between the base station and the terminal includes data and various control information, and various physical channels exist according to the type / use of the information transmitted and received.

FIG. 1 is a diagram for explaining physical channels used in a 3GPP LTE (-A) system and a general signal transmission method using the same.

The terminal which is powered on again or enters a new cell while the power is turned off performs an initial cell search operation such as synchronizing with the base station in step S101. To this end, the UE receives a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station, synchronizes with the base station, and provides information such as a cell identity. Acquire. Thereafter, the terminal may receive a physical broadcast channel (PBCH) from the base station to obtain broadcast information in a cell. Meanwhile, the terminal may check a downlink channel state by receiving a downlink reference signal (DL RS) in an initial cell search step.

After completing the initial cell discovery, the UE receives a physical downlink control channel (PDSCH) according to physical downlink control channel (PDCCH) and physical downlink control channel information in step S102 to be more specific. System information can be obtained.

Thereafter, the terminal may perform a random access procedure such as steps S103 to S106 to complete the access to the base station. To this end, the UE transmits a preamble through a physical random access channel (PRACH) (S103), a response message to the preamble through a physical downlink control channel and a corresponding physical downlink shared channel. Can be received (S104). In case of contention based random access, 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). ) Can be performed.

After performing the above-described procedure, the UE performs a general downlink control channel / physical downlink shared channel reception (S107) and a physical uplink shared channel (PUSCH) / as a general uplink / downlink signal transmission procedure. Physical uplink control channel (PUCCH) transmission (S108) may be performed. The control information transmitted from the terminal to the base station is collectively referred to as uplink control information (UCI). UCI includes Hybrid Automatic Repeat and reQuest Acknowledgment / Negative-ACK (HARQ ACK / NACK), Scheduling Request (SR), Channel State Information (CSI), and the like. The CSI includes a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indication (RI), and the like. UCI is generally transmitted through PUCCH, but may be transmitted through PUSCH when control information and traffic data should be transmitted at the same time. In addition, the UCI may be aperiodically transmitted through the PUSCH by the request / instruction of the network.

2 illustrates a structure of a radio frame. The uplink / downlink data packet transmission is performed in subframe units, and the subframe is defined as a time interval including a plurality of 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).

2 (a) illustrates the structure of a type 1 radio frame. The downlink radio frame consists of 10 subframes, and one subframe consists of two slots in the time domain. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms. One slot includes a plurality of OFDM symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. In the 3GPP LTE system, since OFDM is used in 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 a plurality of consecutive subcarriers in one slot.

The number of OFDM symbols included in the slot may vary depending on the configuration of a cyclic prefix (CP). CP has an extended CP (normal CP) and a normal CP (normal CP). For example, when an OFDM symbol is configured by a normal CP, the number of OFDM symbols included in one slot may be seven. When the OFDM symbol is configured by an extended CP, since the length of one OFDM symbol is increased, the number of OFDM symbols included in one slot is smaller than that of the normal CP. For example, in the case of an extended CP, the number of OFDM symbols included in one slot may be six. When the channel state is unstable, such as when the terminal moves at a high speed, an extended CP may be used to further reduce intersymbol interference.

When the normal CP is used, since the slot includes 7 OFDM symbols, the subframe includes 14 OFDM symbols. First up to three OFDM symbols of a subframe may be allocated to a physical downlink control channel (PDCCH), and the remaining OFDM symbols may be allocated to a physical downlink shared channel (PDSCH).

2 (b) illustrates the structure of a type 2 radio frame. Type 2 radio frames consist of two half frames. The half frame includes 4 (5) normal subframes and 1 (0) special subframes. The general subframe is used for uplink or downlink according to the UL-Downlink configuration. The subframe consists of two slots.

Table 1 illustrates a subframe configuration in a radio frame according to the UL-DL configuration.

Uplink-downlink configuration

Downlink-to-Uplink Switch point periodicity

Subframe number

0

One

2

3

4

5

6

7

8

9

0

5 ms

D

S

U

U

U

D

S

U

U

U

One

5 ms

D

S

U

U

D

D

S

U

U

D

2

5 ms

D

S

U

D

D

D

S

U

D

D

3

10 ms

D

S

U

U

U

D

D

D

D

D

4

10 ms

D

S

U

U

D

D

D

D

D

D

5

10 ms

D

S

U

D

D

D

D

D

D

D

6

5 ms

D

S

U

U

U

D

S

U

U

D

In the table, D represents a downlink subframe, U represents an uplink subframe, and S represents a special subframe. The special subframe includes a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS). DwPTS is used for initial cell search, synchronization or channel estimation at the terminal. UpPTS is used for channel estimation at the base station and synchronization of uplink transmission of the terminal. The guard period is a period for removing interference generated in the uplink due to the multipath delay of the downlink signal between the uplink and the downlink.

The structure of the radio frame is merely an example, and the number of subframes, the number of slots, and the number of symbols in the radio frame may be variously changed.

3 illustrates a resource grid of a downlink slot.

Referring to FIG. 3, the downlink slot includes a plurality of OFDM symbols in the time domain. Here, one downlink slot includes 7 OFDM symbols and one resource block (RB) is illustrated as including 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 contains 12x7 REs. The number NDL of RBs included in the downlink slot depends on the downlink transmission band. The structure of the uplink slot may be the same as the structure of the downlink slot.

4 illustrates a structure of a downlink subframe.

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

Control information transmitted through the PDCCH is referred to as downlink control information (DCI). The DCI format has formats 0, 3, 3A, 4 for uplink, formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C, etc. defined for downlink. The type of the information field, the number of information fields, the number of bits of each information field, etc. vary according to the DCI format. For example, the DCI format may include a hopping flag, an RB assignment, a modulation coding scheme (MCS), a redundancy version (RV), a new data indicator (NDI), a transmit power control (TPC), It optionally includes information such as a HARQ process number and a precoding matrix indicator (PMI) confirmation. Accordingly, the size of control information matched to the DCI format varies according to the DCI format. Meanwhile, any DCI format may be used for transmitting two or more kinds 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.

The PDCCH includes a transmission format and resource allocation of a downlink shared channel (DL-SCH), resource allocation information for an uplink shared channel (UL-SCH), paging information for a paging channel (PCH), and system information on the DL-SCH. ), Resource allocation information of a higher-layer control message such as a random access response transmitted on a PDSCH, transmission power control commands for individual terminals in an arbitrary terminal group, activation of voice over IP (VoIP), and the like. . A plurality of PDCCHs may be transmitted in the control region. The terminal may monitor the plurality of PDCCHs. The PDCCH is transmitted on an aggregation of one or a plurality of consecutive CCEs (consecutive control channel elements). CCE is a logical allocation unit used to provide a PDCCH of a predetermined coding rate according to the state of a radio channel. The CCE corresponds to a plurality of resource element groups (REGs). The format of the PDCCH and the number of bits of the available PDCCH are determined according to 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 of the PDCCH or the intended use. If the PDCCH is for a specific terminal, a unique identifier (eg, C-RNTI (cell-RNTI)) of the terminal is masked on the CRC. As another example, if the PDCCH is for a paging message, a paging indication identifier (eg, p-RNTI (p-RNTI)) is masked in the CRC. If the PDCCH relates to system information (more specifically, a system information block (SIB) to be described later), a system information identifier (eg, a system information RNTI (SI-RNTI)) is masked to 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 transmission of the random access preamble of the terminal.

The PDCCH carries a message known as Downlink Control Information (DCI), and the DCI includes resource allocation and other control information for one terminal or a group of terminals. In general, a plurality of PDCCHs may be transmitted in one subframe. Each PDCCH is transmitted using one or more Control Channel Elements (CCEs), and each CCE corresponds to nine sets of four resource elements. The four resource elements are referred to as resource element groups (REGs). Four QPSK symbols are mapped to one REG. The resource element allocated to the reference signal is not included in the REG, so that the total number of REGs within a given OFDM symbol depends on the presence of a cell-specific reference signal. The REG concept (ie group-by-group mapping, each group contains four resource elements) is also used for other downlink control channels (PCFICH and PHICH). That is, REG is used as a basic resource unit of the control region. Four PDCCH formats are supported as listed in Table 2.

PDCCH format	Numberof CCEs (n)	Number of REGs	Numberof PDCCH bits
0	One	9	72
One	2	8	144
2	4	36	288
3	5	72	576

CCEs are numbered consecutively, and to simplify the decoding process, a PDCCH with a format consisting of n CCEs can only start with a CCE having the same number as a multiple of n. The number of CCEs used for transmission of a specific PDCCH is determined by the base station according to channel conditions. For example, if the PDCCH is for a terminal having a good downlink channel (eg, close to a base station), one CCE may be sufficient. However, in case of a terminal having a bad channel (eg, close to a cell boundary), eight CCEs may be used to obtain sufficient robustness. In addition, the power level of the PDCCH may be adjusted according to channel conditions.

The approach introduced in LTE is to define a limited set of CCE locations where the PDCCH can be located for each terminal. The limited set of CCE locations where the UE can find its own PDCCH may be referred to as a search space (SS). In LTE, the search space has a different size according to each PDCCH format. In addition, UE-specific and common search spaces are defined separately. The UE-Specific Search Space (USS) is set individually for each terminal, and the range of the Common Search Space (CSS) is known to all terminals. UE-specific and common search spaces may overlap for a given terminal. In case of having a relatively small search space, since there are no remaining CCEs when some CCE positions are allocated in the search space for a specific UE, within a given subframe, the base station may not find CCE resources for transmitting the PDCCH to all possible UEs. The UE-specific hopping sequence is applied to the start position of the UE-specific search space in order to minimize the possibility of the above blocking leading to the next subframe.

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

PDCCH format	Numberof CCEs (n)	Number of candidates in common search space	Numberof candidates in dedicated search space
0	One	-	6
One	2	-	6
2	4	4	2
3	8	2	2

In order to keep the computational load according to the total number of blind decoding (BD) under control, the terminal is not required to simultaneously search all defined DCI formats. In general, within a UE-specific search space, the terminal always searches for formats 0 and 1A. Formats 0 and 1A have the same size and are distinguished by flags in the message. In addition, the terminal may be required to receive the additional format (eg, 1, 1B or 2 depending on the PDSCH transmission mode set by the base station). In the common search space, the UE searches for formats 1A and 1C. In addition, the terminal may be configured to search for format 3 or 3A. Formats 3 and 3A have the same size as formats 0 and 1A and can be distinguished by scrambled CRCs with different (common) identifiers, rather than terminal-specific identifiers. PDSCH transmission schemes according to transmission modes and information contents of DCI formats are listed below.

Transmission Mode (TM)

Transmission mode 1: Transmission from a single base station antenna port

● Transmission Mode 2: Transmission Diversity

Transmission Mode 3: Open-Loop Space Multiplexing

Transmission mode 4: closed-loop spatial multiplexing

Transmission Mode 5: Multi-User MIMO

● Transmission mode 6: closed-loop rank-1 precoding

● Transmission Mode 7: Single-antenna Port (Port 5) Transmission

● Transmission Mode 8: Double Layer Transmission (Ports 7 and 8) or Single-Antenna Port (Ports 7 or 8) Transmission

● Transfer Mode 9: Up to eight layer transfers (ports 7 to 14) or single-antenna ports (ports 7 or 8)

DCI format

Format 0: Resource grant for PUSCH transmission (uplink)

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

Format 1A: compact signaling of resource allocation for a single codeword PDSCH (all modes)

Format 1B: Compact resource allocation for PDSCH (mode 6) using rank-1 closed-loop precoding

Format 1C: very compact resource allocation for PDSCH (eg paging / broadcast system information)

Format 1D: compact resource allocation for PDSCH (mode 5) using multi-user MIMO

Format 2: Resource Allocation for PDSCH (Mode 4) of Closed-Root MIMO Operation

Format 2A: resource allocation for PDSCH (mode 3) of open-loop MIMO operation

Format 3 / 3A: power control command with 2-bit / 1-bit power adjustment value for PUCCH and PUSCH

5 illustrates an EPDCCH. EPDCCH is a channel further introduced in LTE-A.

Referring to FIG. 5, a control region (see FIG. 4) of a subframe may be allocated a PDCCH (Legacy PDCCH, L-PDCCH) according to the existing LTE. In the figure, the L-PDCCH region means a region to which an L-PDCCH can be allocated. Meanwhile, a PDCCH may be additionally allocated in a data region (eg, a resource region for PDSCH). The PDCCH allocated to the data region is called an EPDCCH. As shown, by additionally securing control channel resources through the EPDCCH, scheduling constraints due to limited control channel resources in the L-PDCCH region can be relaxed. Like the L-PDCCH, the EPDCCH carries a DCI. For example, the EPDCCH may carry downlink scheduling information and uplink scheduling information. For example, the terminal may receive an EPDCCH and receive data / control information through a PDSCH corresponding to the EPDCCH. In addition, the terminal may receive the EPDCCH and transmit data / control information through a PUSCH corresponding to the EPDCCH. The EPDCCH / PDSCH may be allocated from the first OFDM symbol of the subframe according to the cell type. Unless otherwise specified, the PDCCH herein includes both L-PDCCH and EPDCCH.

6 illustrates a structure of an uplink subframe used in LTE (-A).

Referring to FIG. 6, the subframe 500 is composed 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. The 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 area means a communication resource used in transmitting data such as voice and packet transmitted to each terminal, and includes a PUSCH (Physical Uplink Shared Channel). The control region means a communication resource used to transmit an uplink control signal, for example, a downlink channel quality report from each terminal, a received ACK / NACK for an uplink signal, an uplink scheduling request, and a PUCCH (Physical Uplink). Control Channel). The sounding reference signal (SRS) is transmitted through an SC-FDMA symbol located last on the time axis in one subframe. SRSs of multiple terminals transmitted in the last SC-FDMA of the same subframe can be distinguished according to frequency location / sequence. The SRS is used to transmit an uplink channel state to a base station, and is periodically transmitted according to a subframe period / offset set by a higher layer (eg, an RRC layer), or aperiodically at the request of the base station.

7 is a diagram for explaining an SC-FDMA scheme and an OFDMA scheme. The 3GPP system employs OFDMA in downlink and SC-FDMA in uplink.

Referring to FIG. 7, both a terminal for uplink signal transmission and a base station for downlink signal transmission include a serial-to-parallel converter (401), a subcarrier mapper (403), and an M-point IDFT module (404). ) And the Cyclic Prefix (CP) addition module 406 are the same. However, the terminal for transmitting a signal in the SC-FDMA scheme further includes an N-point DFT module 402. The N-point DFT module 402 partially offsets the IDFT processing impact of the M-point IDFT module 404 so that the transmitted signal has a single carrier property.

Next, HARQ (Hybrid AutomaticRepeat reQuest) will be described. When there are a plurality of terminals having data to be transmitted in uplink / downlink in a wireless communication system, the base station selects a terminal to transmit data for each transmission time interval (TTI) (eg, subframe). In a multi-carrier and similarly operated system, the base station selects terminals to transmit data in uplink / downlink for each TTI and selects a frequency band used by the terminal for data transmission.

Referring to the uplink, UEs transmit reference signals (or pilots) in uplink, and the base station determines the channel state of the UEs using the reference signals transmitted from the UEs in each unit frequency band for each TTI. Select terminals to transmit data in the uplink. The base station informs the terminal of this result. That is, the base station transmits an uplink assignment message for transmitting data using a specific frequency band to an uplink scheduled terminal in a specific TTI. 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 allocation message may include a UE ID, RB allocation information, a Modulation and Coding Scheme (MCS), a Redundancy Version (RV) version, a New Data Indicator (NDI), and the like.

In the case of the synchronous HARQ scheme, the retransmission time is systematically promised (for example, 4 subframes after the NACK reception time) (synchronous HARQ). Therefore, the UL grant message transmitted from the base station to the terminal only needs to be transmitted during initial transmission, and subsequent retransmission is performed by an ACK / NACK signal (eg, PHICH signal). In the asynchronous HARQ scheme, since the retransmission time is not promised to each other, the base station should send a retransmission request message to the terminal. In addition, in the non-adaptive HARQ scheme, the frequency resource or MCS for retransmission is the same as the previous transmission. In the adaptive HARQ scheme, the frequency resource or MCS for the retransmission may be different from the previous transmission. For example, in the case of the asynchronous adaptive HARQ scheme, since the frequency resource or the MCS for retransmission varies for each transmission time point, the retransmission request message may include a terminal ID, RB allocation information, HARQ process ID / number, RV, and NDI information. .

8 illustrates 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, the HARQ process number is given from 0 to 7. One HARQ process operates per TTI (eg, subframe). Referring to FIG. 8, the base station 110 transmits a UL grant to the terminal 120 through the PDCCH (S600). The terminal 120 transmits uplink data to the base station S110 using the RB and MCS designated by the UL grant after 4 subframes (eg, subframe 4) from the time point (eg, subframe 0) at which the UL grant is received. It transmits (S602). The base station 110 generates ACK / NACK after decoding uplink data received from the terminal 120. If decoding on the uplink data fails, the base station 110 transmits a NACK to the terminal 120 (S604). The terminal 120 retransmits uplink data after 4 subframes from the time point of receiving the NACK (S606). Initial transmission and retransmission of uplink data is in charge of the same HARQ processor (eg, HARQ process 4). ACK / NACK information may be transmitted through PHICH.

Meanwhile, the DL HARQ scheme in the LTE (-A) system 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 by using the RB and MCS designated by the DL grant at a time point (eg, subframe 0) at which the DL grant is received. The terminal 120 generates ACK / NACK after decoding downlink data. If decoding of the downlink data fails, the terminal 120 transmits a NACK to the base station 110 after 4 subframes (for example, subframe 4) from the time point of receiving the downlink data. Thereafter, the base station 110 transmits a DL grant to the terminal 120 instructing retransmission of downlink data through the PDCCH at a desired time point (eg, subframe X). The terminal 120 re-receives downlink data from the base station S110 using the RB and MCS designated by the DL grant at a time point (eg, subframe X) when the DL grant is received.

There are a plurality of parallel HARQ processes for DL / UL transmission in the base station / terminal. Multiple parallel HARQ processes allow DL / UL transmissions to be performed continuously while waiting for HARQ feedback for successful or unsuccessful reception for previous DL / UL transmissions. Each HARQ process is associated with a HARQ buffer of a medium access control (MAC) layer. Each HARQ process manages state variables related to the number of transmissions of the MAC Physical Data Block (PDU) in the buffer, HARQ feedback for the MAC PDU in the buffer, the current redundancy version, and the like.

The HARQ process is responsible for reliable transmission of data (eg, transport blocks (TBs)). In channel coding, a transport block may be divided into one or more code blocks (CBs) in consideration of the size of a channel encoder. After channel coding, one or more code blocks are combined to form a codeword (Codeword, CW) corresponding to the transport block.

9 illustrates a process of a transport block (TB). 9 may be applied to data of a DL-SCH, a PCH, and a multicast channel (MCH) transport channel. The uplink TB (or data of the uplink transport channel) may be similarly processed.

Referring to FIG. 9, the transmitter performs a CRC (eg 24-bit) (TB CRC) to check the TB for error. Thereafter, the transmitter may divide TB + CRC into a plurality of code blocks in consideration of the size of the channel encoder. The maximum size of a code block in LTE (-A) is 6144-bits. Therefore, if the TB size is 6144-bit or less, no code block is configured. If the TB size is larger than 6144-bit, the TB is divided into 6144-bit units to form a plurality of code blocks. Each code block is separately appended with a CRC (eg 24-bit) (CB CRC) for error checking. Each code block undergoes channel coding and rate matching, and then merges into one to form a codeword. In LTE (-A), data scheduling and a corresponding HARQ process are performed in TB units, and CB CRC is used to determine early termination of TB decoding.

The HARQ process is associated with soft buffers for transport blocks and soft buffers for code blocks in the PHY (Physical) layer. A circular buffer of length K _w = 3 K _π for the r-th code block at the transmitting end is generated as follows.

The N _IR bit represents the soft buffer size for the transport 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.

N _IR is as follows.

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

If N _soft = 35982720, K _C = 5,

If else if N _soft = 3654144 and the UE can support up to two spatial layers for the DL cell, K _C = 2

else K _C = 1

End if.

K _MIMO is 2 when the terminal is configured to receive PDSCH transmission based on transmission mode 3, 4, 8 or 9, and 1 otherwise.

M _{DL_HARQ} is the maximum number of DL HARQ processes.

M _limit is 8.

In FDD and TDD, when the UE is configured to have two or more serving cells, and for at least K _MIMO · min ( M _{DL_HARQ} , M _limit ) transport blocks for each serving cell, when decoding of a code block of the transport block fails, At least

Store the received soft channel bits corresponding to the range of. n _SB is given by the following equation.

w _k , C , N _cb , K _MIMO , and M _limit are as defined above.

M _{DL_HARQ} is the maximum number of DL HARQ processes.

Is the number of configured serving cells.

Is the total number of soft channel bits according to the terminal capability.

In determining k , the terminal prioritizes storage of soft channel bits corresponding to k of low values. w _k corresponds to the received soft channel bits. range

May include a subset that the received soft channel bits do not include.

Scheduling for UL transmission in LTE is possible only when the UL transmission timing of the terminal is synchronized. The random access procedure is used for various purposes. For example, the random access procedure is performed at the initial network access, handover, and data generation. In addition, the terminal may obtain a UL synchronization through a random access process. If UL synchronization is obtained, the base station may allocate resources for UL transmission to the corresponding terminal. The random access process is divided into a contention based process and a non-contention based process.

10 illustrates a collision based random access procedure.

Referring to FIG. 10, a terminal receives information about a random access from a base station through system information. Thereafter, if the 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, the downlink scheduling information for the random access response message may be CRC masked with a random access-RNTI (RA-RNTI) and transmitted on an L1 / L2 control channel (PDCCH). The UE that receives the downlink scheduling signal masked by the RA-RNTI may receive and decode a random access response message from the PDSCH. Thereafter, the terminal checks whether there is random access response information indicated to the random access response message. Whether the random access response information indicated to the presence of the self may be determined by whether there is a random access preamble ID (RAID) 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 (eg, T-CRNTI) for terminal identification. Upon receiving the random access response information, the terminal transmits an uplink message (also referred to as message 3) to an uplink shared channel (SCH) according to 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 called message 4) message to the terminal (S740).

11 illustrates a non-collision based random access procedure. The non-collision based random access procedure may exist when used in the handover procedure or requested by the command of the base station. The basic process is the same as the competition based random access process.

Referring to FIG. 11, the UE is allocated a random access preamble (ie, a dedicated random access preamble) for itself from the base station (S810). Dedicated random access preamble indication information (eg, preamble index) may be included in the handover command message or received through the PDCCH. The terminal transmits a 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 ends.

DCI format 1A is used to initiate a non-collision based random access procedure with a PDCCH order. DCI format 1A is also used for compact scheduling for one PDSCH codeword. The following information is transmitted using DCI format 1A.

-Flag to distinguish DCI format 0 / 1A: 1 bit. The flag value 0 represents DCI format 0, and the flag value 1 represents DCI format 1A.

When the CRC of DCI format 1A is scrambled to C-RNTI and all remaining fields are set as follows, DCI format 1A is used for a random access procedure by a PDCCH command.

Localized / distributed Virtual Resource Block (VRB) allocation flag: 1 bit. The flag is set to zero.

Resource block allocation information:

beat. All bits are set to one.

Preamble Index: 6 bits

PRACH mask index: 4 bits

In DCI format 1A, all remaining bits are set to zero for compact scheduling of PDSCH codewords.

12 illustrates a Carrier Aggregation (CA) communication system.

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

For cross-CC scheduling, a carrier indicator field (CIF) is used. Configuration for the presence or absence of CIF in the PDCCH may be semi-statically enabled by higher layer signaling (eg, RRC signaling) to be UE-specific (or UE group-specific). The basics of PDCCH transmission can be summarized as follows.

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

  ● No CIF

■ CIF enabled: A PDCCH on a DL CC may allocate a PDSCH or PUSCH resource on one DL / UL CC among a plurality of merged DL / UL CCs using the CIF.

  LTE DCI format extended to have CIF

    CIF (if set) is a fixed x-bit field (eg x = 3)

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

In the presence of CIF, the base station may allocate a monitoring DL CC (set) to reduce the BD complexity at the terminal side. For PDSCH / PUSCH scheduling, the UE may perform detection / decoding of the PDCCH only in the corresponding DL CC. In addition, the base station may transmit the PDCCH only through the monitoring DL CC (set). The monitoring DL CC set may be set in a terminal-specific, terminal-group-specific or cell-specific manner.

13 illustrates scheduling when a plurality of carriers are merged. Assume that three DL CCs are merged. Assume that DL CC A is set to PDCCH CC. DL CC A to C may be referred to as a serving CC, a serving carrier, a serving cell, and the like. If CIF is disabled, each DL CC can transmit only PDCCH scheduling its PDSCH without CIF according to the LTE PDCCH rule (non-cross-CC scheduling). On the other hand, if CIF is enabled by UE-specific (or UE-group-specific or cell-specific) higher layer signaling, a specific CC (eg, DL CC A) schedules PDSCH of DL CC A using CIF. Not only PDCCH but also PDCCH scheduling PDSCH of another CC may be transmitted (cross-CC scheduling). On the other hand, PDCCH is not transmitted in DL CC B / C.

On the other hand, the millimeter wave (mmW) has a short wavelength of the signal, it is possible to install a plurality of antennas in 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 5 by 5 cm panel in a two-dimensional array of 0.5 λ (wavelength) spacing. Therefore, mmW systems attempt to use multiple antenna elements to increase the beamforming (BF) gain to increase coverage or to increase throughput.

In this regard, if a TXRU (transceiver unit) is provided to enable transmission power and phase adjustment for each antenna element, independent beamforming is possible for each frequency resource. However, it is less cost effective to install TXRU in all 100 antenna elements. Therefore, a method of mapping a plurality of antenna elements to one TXRU and adjusting the direction of the beam with an analog phase shifter is considered. The analog beamforming method has a disadvantage in that only one beam direction can be made in the entire band and thus no frequency selective beam can be made. We can consider a hybrid BF with fewer B TXRUs than Q antenna elements in the form of digital BF and analog BF. In this case, although there are differences depending on the connection scheme of the B TXRU and the Q antenna elements, the direction of the beam that can be simultaneously transmitted is limited to B or less.

14 illustrates analog beamforming. Referring to FIG. 14, a transmitter transmits a signal by changing a direction of a beam over time (transmission beamforming), and a receiver may receive a signal by changing a direction of a beam over time (receive beamforming). Within a certain period of time, (i) the transmit and receive beams change direction of the beam simultaneously with time, (ii) the transmit beam only changes direction of the receive beam with time, or (iii) receive In the fixed state, only the direction of the transmission beam may change with time.

Meanwhile, in the next generation of radio access technology (RAT), self-contained subframes are considered to minimize data transmission latency. 15 illustrates the structure of a self-completed subframe. In FIG. 15, hatched areas represent DL control areas, and black areas represent UL control areas. An area without an indication may be used for DL data transmission or may be used for UL data transmission. Since DL and UL transmissions are sequentially performed in one subframe, DL data may be transmitted in a subframe and UL ACK / NACK may be received. As a result, when data transmission error occurs, it takes less time to retransmit data, thereby minimizing the transmission latency of final data.

As an example of a configurable / configurable self-complete subframe type, at least the following four subframe types may be considered. Each interval is listed in chronological order.

DL control section + DL data section + GP (Guard Period) + UL control section

DL control section + DL data section

DL control section + GP + UL data section + UL control section

DL control section + GP + UL data section

PDFICH, PHICH, PDCCH may be transmitted in the DL control period, and PDSCH may be transmitted in the DL data period. PUCCH may be transmitted in the UL control period, and PUSCH may be transmitted in the UL data period. The GP provides a time gap in the process of the base station and the terminal switching from the transmission mode to the reception mode or from the reception mode to the transmission mode. Some OFDM symbols at the time of switching from DL to UL in the subframe may be set to GP.

Example

In the case of the existing LTE system, when the size of the DL data (ie, TBS) is greater than or equal to a certain level, the bit stream (ie, TB) to be transmitted through the PDSCH is divided into a plurality of CBs, and channel coding and CRC for each CB. Is applied (see Fig. 9). If any one of the plurality of CBs included in one TB fails to receive (eg, decode), the terminal reports a HARQ-ACK feedback corresponding to the TB to the base station as a NACK. In this way, the base station retransmits all the CB corresponding to the TB. In other words, the HARQ operation on the DL data in the legacy LTE (-A) is performed based on the TB scheduling / transmission from the base station and the HARQ-ACK feedback configuration of the TB unit from the terminal corresponding thereto.

On the other hand, next-generation RAT (hereinafter referred to as a new RAT) system may basically have a larger system (carrier) (BW) bandwidth than LTE, and thus (maximum) TBS is likely to be larger than that of existing LTE. Accordingly, the number of CBs constituting one TB may also be greater than in LTE. Therefore, if HARQ-ACK feedback in units of TB is performed in the new RAT system as before, even if a decoding error (that is, NACK) occurs for only a few CBs, retransmission scheduling in units of TB is involved, so resource use efficiency is improved. Can be degraded. In addition, in the new RAT system, a small (symbol) of a portion of resources allocated for transmission of delay-insensitive data type 1 (eg, enhanced Mobile BroadBand, eMBB) having a large time interval (TTI), Delay-sensitive data type 2 (eg, Ultra-Reliable Low Latency Communications, URLLC) having a time interval (TTI) may be transmitted in the form of puncturing data type 1. In this case, the decoding error (i.e., NACK) is concentrated only on a specific part of the plurality of CBs constituting one TB for data type 1 due to the influence of an interference signal having a time-selective characteristic. This may occur.

In view of the characteristics of the new RAT system, the present invention proposes a method of performing (retransmission) scheduling in units of CB or CBG and configuring / transmitting HARQ-ACK feedback in units of CB / CBG. Specifically, the present invention proposes a method of configuring a CBG, a method of configuring HARQ-ACK (hereinafter, A / N) feedback, a method of operating a reception soft buffer of a terminal, and a handling method for a specific mismatch situation. do.

For convenience, the proposed methods of the present invention are divided into various embodiments, but these are for convenience of description and they may be used in combination with each other.

First, the abbreviation / term used in this invention is demonstrated.

TBS: TB size. Total number of bits that make up the TB

CB: code block

CB size: the total number of bits constituting the CB

CBG: code block group. All CBs (which constitute a single TB) may be set to one CBG, some multiple CBs may be configured as one CBG, or one CB may be configured as one CBG.

A / N: HARQ-ACK response. That is, it may mean ACK, NACK, and DTX. DTX indicates the case of missing the PDCCH. The A / N bit may be set to 1 in the case of ACK and to 0 in the case of NACK. Can be used equivalent to HARQ-ACK, ACK / NACK.

-CBG-based A / N: Since the CRB is not added to the CBG, an A / N for the CBG can be generated based on an error check result for the CB in the CBG. For example, when all the CBs in the CBG are successfully detected, the UE sets an A / N response (or A / N bit) to the ACK for the CBG, and when any one of the CBs in the CBG is not successfully detected. The UE may set an A / N response (or A / N bit) ACK to the CBG (logical AND). The A / N payload for the CBG (s) of the TB includes a plurality of A / N (response) bits, and each A / N (response) bit corresponds one-to-one to the CBG of the TB.

CBG-based retransmission: TB retransmission may be performed in units of CBG in response to CBG-based A / N. For example, when the base station retransmits a TB to the terminal, the base station may perform retransmission only for the CBG having received the NACK from the terminal. At this time, upon retransmission of the TB corresponding to the same HARQ process as the previous transmission of the TB, the CB (s) in the CBG remain the same as the initial transmission of the TB.

CBG size: the number of CBs constituting the CBG

CBG index: an index that distinguishes between CBGs. Depending on the context, a CBG index may be used equivalent to a CBG having that index.

Symbol: Unless otherwise distinguished, this may mean an OFDMA symbol or an SC-FDMA symbol.

floor (X): Descending function. It means the maximum integer below X.

ceiling (X): Rounding function. It means the minimum integer greater than or equal to X.

mod (A, B): The remainder of A divided by B.

(X) how to configure CB

1) Method X-1: Given the number of bits Cn constituting one CB, based on the configuration, Cm CBs

The number of bits Cn constituting one CB is predefined with the same single value regardless of TBS or with different TBS values (e.g., proportional to TBS), or semi-static signaling (e.g. RRC signaling) or The terminal may be instructed through dynamic signaling (eg, DCI). Accordingly, when the total number of bits constituting 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 composed of (Cn + mod (Ck, Cn)) bits, and the remaining (Cm-1) CBs may each consist of Cn bits. In the latter case, only one CB may consist of mod (Ck, Cn) bits and the remaining (Cm-1) CBs may each consist of Cn bits. In the former case, Cn may mean the minimum number of bits constituting one CB, and in the latter case, Cn may mean the maximum number of bits constituting one CB.

Alternatively, a method of even-equal allocation of bits per CB to the entire CB may be applied. For example, in the case where Cm = floor (Ck / Cn) CBs are configured, mod (Ck, Cn) CBs may consist of (Cn + 1) bits, and the remaining CBs may consist of Cn bits. have. In addition, when Cm = ceiling (Ck / Cn) CBs are configured, (Cn-mod (Ck, Cn)) CBs may be configured with (Cn-1) bits and the remaining CBs may be configured with Cn bits. In the former case, Cn may mean the minimum number of bits constituting one CB, and in the latter case, Cn may mean the maximum number of bits constituting one CB.

On the other hand, if the above method is applied, one or more specific CBs (hereinafter, small CBs) among the total Cm CBs may be configured with fewer bits than other CBs (hereinafter, regular CBs). Accordingly, a method of grouping Cm CBs having an uneven size into M plurality of CBGs may be needed. Specifically, the total CB number Cm may be divided into a case where the total CB number Cm is a multiple of the CBG number M and a case where the total CB number Cm is not. The following CB grouping scheme may be considered for each. In the following description, the CBG size may mean the number of CBs per CBG. On the other hand, when Cm is not a multiple of M, the size may be different for each CBG, and the size difference between CBGs may be limited to at most one CB.

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

-Opt 1-1: configure small CB to be distributed among all CBGs as much as possible

Opt 1-2: configure small CBs to belong to as few CBGs as possible

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

-Opt 2-1: Configured to belong to a large CBG so that it becomes a small CB

-Opt 2-2: Configured to belong to the small sized CBG to become small CB

Opt 2-3: Apply Opt 1-1 or Opt 1-2

As an example, with Cm = 7 and CB indexes 1/2/3/4/5/6/7 each configured with 5/5/5/5/5/5/2 bits, we can consider M = 3 CBG configurations. have. Here, if Opt 2-1 is applied, CB indexes {1, 2}, {3, 4}, {5, 6, 7} may be configured with CBG indexes 1/2/3, respectively, and Opt 2-2 When applied, the CB indexes {1, 2, 3}, {4, 5}, and {6, 7} may be configured as CBG indexes 1/2/3, respectively. As another example, with Cm = 7 and CB indexes 1/2/3/4/5/6/7 each configured with 5/5/5/5/4/4/4 bits, we can consider M = 3 CBG configurations. have. Here, CB indexes {1, 2}, {3, 4}, {5, 6, 7} are applied when Opt 2-1 is applied, and CB indexes {1, 2, 3}, {are applied when Opt 2-2 is applied. 4, 5} and {6, 7} may be configured as CBG index 1/2/3, respectively. On the other hand, if Opt 1-1 is applied, CB indexes {1, 2, 5}, {3, 6}, {4, 7}. If Opt 1-2 is applied, CB indexes {1, 2}, {3, 4}, {5, 6, 7} may be configured as CBG index 1/2/3, respectively.

In addition, the size of the CBG having high retransmission probability can be reduced as much as possible by including the minimum number of CBs in the CBG corresponding to the portion where the decoding reliability may be low. For example, where the decoding reliability may be low, the CB size of the radio signal may be relatively small, the radio signal may be far from time in the DMRS, the radio signal may be far from the CSI feedback point, or the radio signal may be This may be the case when the SRS (or PUCCH or PRACH) is mapped to an adjacent (OFDMA / SC-FDMA) symbol. To this end, CBG can be configured as follows.

a) Construct a regular CB in X-bit units starting from a low CB index, and construct a small CB in Y-bit units starting from a specific CB index (Y <X).

b) Construct a regular CBG by grouping the CBs from the low CBG index (from CB of the low CB index) to M CBs, and then configure small CBGs by grouping the K CBs from the specific CBG index (K <M). Here, the size difference between CBGs may be limited to a maximum of one CB as proposed above (eg, M = K + 1). According to a) and b), compared to the low index CBG, the high index CBG may have a relatively small CBG size, and may have more small CBs even though the CBG sizes are the same.

c) Signals are sequentially mapped in a frequency-first (or time-first) manner from the CBG of the low CBG index. Here, compared with the high index CBG, the low index CBG may be mapped to a resource having a relatively high decoding reliability.

On the other hand, when Cn> Ck, all bits of TB are configured by a single CB, and one CB including Ck bits may be configured.

2) Method X-2: Given the total number of CBs Cm, and constructing each CB in units of Cn bits based on this

The total number of CBs Cm is predefined with the same single value irrespective of TBS or different values (e.g. proportional to TBS) per TBS, or semi-static signaling (e.g. RRC signaling) or dynamic signaling (e.g. It may be indicated to the terminal through DCI). For example, if the total number of bits constituting the TB is Ck, each CB may be configured in units of Cn = floor (Ck / Cm) or Cn = ceiling (Ck / Cm) bits. In the former case, only one CB may consist of (Cn + mod (Ck, Cn)) bits, and the remaining (Cm-1) CBs may each consist of Cn bits. In the latter case, only one CB may consist of mod (Ck, Cn) bits, and the remaining (Cm-1) CBs may each consist of Cn bits. In the former case, Cn may mean the minimum number of bits constituting one CB, and in the latter case, Cn may mean the maximum number of bits constituting one CB.

Alternatively, a method of even-equal allocation of bits per CB to the entire CB may be applied. For example, in the case where CB is composed of Cn = floor (Ck / Cm) bits, mod (Ck, Cm) CBs have (Cn + 1) (or, ceiling (Ck / Cm) Bits) and the remaining (Cm-mod (Ck, Cm)) CBs may consist of Cn bits. Cn = CB consists of ceiling (Ck / Cm) bits, (Cm-mod (Ck, Cm)) CBs consist of (Cn-1) (or floor (Ck / Cm)) bits The remaining mod (Ck, Cm) CBs may consist of Cn bits. In the former case, Cn may mean the minimum number of bits constituting one CB, and in the latter case, Cn may mean the maximum number of bits constituting one CB.

3) Method X-3: Given the minimum number of bits Tm constituting one CB, and constructing the CB based on this

All CBs constituting one TB may be set to include at least Tm or more bits. For example, assuming TBS as Ck, an operation of calculating Cm.max, which is the maximum Cm value that satisfies the relationship of Ck / Cm Tm, and splitting the TB into Cm.max CBs may be considered.

4) Method X-4: Scheduling in units of CBs and grouping between multiple CBs when the number of CBs is above a certain level

Only when the total number of CBs K constituting one TB is Ts or more, the CB or CBG (retransmission) scheduling may be set / defined to be applied. In addition, when the total number of CBs K is Tg or more, a plurality of CBs may be grouped and configured to define one CBG (eg, Ts <Tg). Here, the number of bits Cn constituting one CB may be defined in advance or may be given through specific signaling (eg, RRC signaling, DCI).

(A) How to Configure CBG

1) Method A-1: The number of CBs constituting one CBG is given and based on this, M CBGs are configured.

The number of CBs constituting one CBG is previously defined with the same single value regardless of TBS or with different TBSs (e.g., proportional to TBS), semi-static signaling (e.g. RRC signaling) or dynamic The terminal may be instructed through signaling (eg, DCI). For example, when the total number of CBs constituting TB is K, M = floor (K / N) or M = ceiling (K / N) CBGs may be configured. In the former case, only one CBG may consist of (N + mod (K, N)) CBs, and the remaining (M-1) CBGs may each consist of N CBs. In the latter case, only one CBG may consist of mod (K, N) CBs, and the remaining (M−1) CBGs may each consist of N CBs. In the former case, N may mean the minimum number of CBs constituting one CBG, and in the latter case, N may mean the maximum number of CBs constituting one CBG. Meanwhile, the terminal may configure and transmit A / N bits for each CBG.

Alternatively, a method of uniformly allocating the number of CBs per CBG to all CBGs may be applied. For example, in the case where M = floor (K / N) CBGs, mod (K, N) CBGs consist of (N + 1) CBs, and the remaining CBGs consist of N CBs. Can be. Also, when M = ceiling (K / N) CBGs, (N-mod (K, N)) CBGs may be composed of (N-1) CBs, and the remaining CBGs may be composed of N CBs. have. In the former case, N may mean the minimum number of CBs constituting one CBG, and in the latter case, N may mean the maximum number of CBs constituting one CBG.

On the other hand, in the case of N> K, all CBs constituting TB belong to a single CBG, and one CBG including K CBs may be configured.

2) Method A-2: Given the total number of CBGs M and constructing each CBG in units of N CBs

The total number of CBGs M is predefined with the same single value regardless of TBS or with different TBSs (e.g., proportional to TBS), or semi-static signaling (e.g. RRC signaling) or dynamic signaling (e.g. It may be indicated to the terminal through DCI). The terminal may identify / configure the CBG from the CBs of the TB based on the total number of CBGs. For example, when the total number of CBs constituting the TB is K, each CBG may be configured in units of N = floor (K / M) or N = ceiling (K / M) CBs. In the former case, only one CBG may consist of (N + mod (K, N)) CBs, and the remaining (M-1) CBGs may each consist of N CBs. In the latter case, only one CBG may consist of mod (K, N) CBs, and the remaining (M−1) CBGs may each consist of N CBs. In the former case, N may mean the minimum number of CBs constituting one CBG, and in the latter case, N may mean the maximum number of CBs constituting one CBG. Meanwhile, the terminal may configure and transmit A / N bits for each CBG. For example, the UE may configure M A / N bits for TB, and each A / N bit may represent an A / N result for the corresponding CBG. .

Alternatively, a method of uniformly allocating the number of CBs per CBG to all CBGs may be applied. For example, in the case of N = floor (K / M) CBG configuration in units of CB, mod (K, M) CBGs have (N + 1) (or, ceiling (K / M) pieces ) CB, and the remaining (M-mod (K, M)) CBGs may consist of N (or floor (K / M)) CBs. In addition, when N = ceiling (K / M) CBG units, (M-mod (K, M)) CBGs have (N-1) (or floor (K / M)) CBs The remaining mod (K, M) CBGs may consist of N (or ceiling (K / M)) CBs. In the former case, N may mean the minimum number of CBs constituting one CBG, and in the latter case, N may mean the maximum number of CBs constituting one CBG.

On the other hand, in the case of M> K, each of the CBs becomes one CBG, so that a total of K CBGs may be configured. In this case, 1) All A / N feedback is composed of M bits, and (M-K) bits that do not correspond to actual CBG are treated as NACK or DTX, or 2) A / N feedback itself corresponds to actual CBG. One can consider how to configure only K bits.

16 illustrates a signal transmission process according to the present invention.

Referring to FIG. 16, the terminal may receive information on the number M of code block groups per transport block from the base station through an upper layer signal (eg, an RRC signal) (S1602). Thereafter, the terminal can receive the initial data transmission from the base station (via PDSCH) (S1604). Here, the data may include a transport block, the transport block may include 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 ceiling (K / M) code blocks, and the remaining code blocks may include flooring (K / M) 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 to the base station for the data (S1606), and the base station may perform data retransmission based on the code block group (S1608). A / N information may be transmitted through PUCCH or PUSCH. Here, the A / N information may include a plurality of A / N bits for data, and each of the A / N bits may represent each A / N response generated in units of code block groups for data. The payload size of the A / N information may remain the same based on M regardless of the number of code block groups constituting the data.

3) Method A-3: CBG Construction Based on Tree (or Nested) Structure for CBG Count M and CBG Size N

The CBG may be configured to have a tree structure for the total number of CBGs M (eg, M1, M2, ...) and the CBG size N (eg, N1, N2, ...). In this case, a plurality of different CBG configurations based on a plurality of different (M, N) combinations may be set for one TB (size). For different (M, N) combinations, considering the CBG configuration in the case of (M1, N1) and (M2, N2), it may be set to N1> N2 when M1 <M2. In addition, one CBG in the case of (M1, N1) may be configured to include one or more CBGs in the case of (M2, N2). Conversely, one CBG in the case of (M2, N2) may be configured to belong to only one specific CBG in the case of (M1, N1). In addition, M2 may be set to a multiple of M1 and / or N1 may be set to a multiple of N2. M may be set to 2 ^m (m = 0, 1, ...). Meanwhile, one (or plural) of the indexes for M, N or (M, N) combinations, or possible CBG indexes based on all (M, N) combinations, may be either semi-static signaling (eg, RRC signaling) or dynamic signaling. (Eg, DCI) may be indicated to the UE. The UE may configure and transmit A / N bits for each CBG configured to correspond to the corresponding index. M and N may be previously defined with the same single value regardless of TBS, or may be predefined with other TBS-specific values (eg, proportional to TBS).

For example, assuming that the total number of CBs constituting TB is K = 16 and each CB is indexed with k = 0, 1, ..., 15, the number of CBGs is M = {1, 2, 4, 8, 16} and the corresponding CBG size may be set to N = K / M = {16, 8, 4, 2, 1} (nested CBG example 1).

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

b) When (M, N) = (2, 8), two CBGs are constructed and contain eight different CBs for each CBG. In this case one CBG includes two CBGs when (M, N) = (4, 4).

c) If (M, N) = (4, 4), four CBGs are constructed and include four different CBs for each CBG. In this case, one CBG includes two CBGs when (M, N) = (8, 2).

d) If (M, N) = (8, 2), eight CBGs are constructed and include two different CBs for each CBG.

e) When (M, N) = (16, 1), 16 CBGs are constructed and contain only one CB that is different for each CBG.

As in the above example, the index of a particular M, N or (M, N) combination, or all (M, N), with a plurality of different (M, N) combinations and thus CBG numbers / sizes preconfigured / specified N) One (or plural) of possible CBG indexes based on the combination may be indicated to the UE. In this example, there are a total of five possible M, N, or (M, N) combinations, and the possible CBG indexes for all (M, N) combinations are (the possible M values {1, 2, 4, 8, 16} This is the case when the total is set as 31. The UE may perform decoding and corresponding A / N feedback configuration / transmission with assuming a CBG configuration corresponding to M and / or N index with respect to the scheduled DL data (eg, TB or CBG).

Generalizing the method, one TB with only the condition that is set to N1 N2 when M1 <M2 for the CBG configuration when different (M, N) combinations (M1, N1) and (M2, N2) A plurality of CBG configurations can be set for (size). For example, assuming that the total number of CBs constituting TB is K = 6 and each CB is indexed with k = 0, 1, ..., 5, the number of CBGs is M = {1, 2, 3, 6} and a corresponding CBG size of N = K / M = {6, 3, 2, 1} may be considered (nested CBG example 2).

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

b) When (M, N) = (2, 3), two CBGs are constructed and contain three different CBs for each CBG. For example, a set of CB indexes {0, 1, 2} and {3, 4, 5} each constitute one CBG.

c) When (M, N) = (3, 2), three CBGs are constructed and include two different CBs for each CBG. For example, a set of CB indexes {0, 1}, {2, 3}, and {4, 5} each constitute one CBG.

d) When (M, N) = (6, 1), six CBGs are constructed and only one CB differs for each CBG.

As another example, assuming that the total number of CBs constituting TB is K = 9 and each CB is indexed with k = 0, 1, ..., 8, the number of CBGs is M = {1, 2, 3 , 6} and a corresponding CBG size of N = {9, (5 or 4), 3, (2 or 1)} may be considered (nested CBG example 3).

a) If (M, N) = (1, 9), then only one CBG is constructed and that CBG contains all nine CBs.

b) When (M, N) = (2, 5 or 4), a total of two CBGs are constructed, one CBG contains 5 and the other CBG contains 4 CBs, respectively. For example, a set of CB indexes {0, 1, 2, 3, 4} and {5, 6, 7, 8} each constitute one CBG.

c) When (M, N) = (3, 3), three CBGs are constructed and include three different CBs for each CBG. For example, a set of CB indexes {0, 1, 2}, {3, 4, 5} and {6, 7, 8} each constitute one CBG.

d) When (M, N) = (6, 2 or 1), a total of six CBGs are constructed, of which three CBGs comprise two CBs and the other three CBGs comprise one CB, respectively. For example, a set of CB indexes {0, 1}, {2, 3}, {4, 5}, {6}, {7}, and {8} each constitute one CBG.

In the nested CBG example 2/3, a total of 12 (= 1 + 2 + 3 + 6) CBGs (based on four different (M, N) combinations) may be indexed. Based on this, the base station may indicate a CBG scheduled for retransmission (via DCI) and / or the terminal may configure and transmit A / N feedback for the indicated CBG.

Meanwhile, in consideration of DCI overhead for scheduling target CBG indication and / or UCI overhead for corresponding A / N feedback configuration, the total number of CBG indexes configured in the nested form L is equally set for each TBS or TBS. The L value for each TBS may be set such that the bit overhead for the CBG indication is the same (eg, the ceiling (log ₂ (L)) value is the same).

4) Method A-4: CBs belonging to a certain number of symbol sets (and a certain number of RB sets) into one CBG

In a state in which a time interval (and / or frequency domain) in which a TB is transmitted is divided into a plurality of symbol sets (hereinafter, Symbol Groups, SGs) (and / or a plurality of RB sets (hereinafter, RB Groups, RBGs)), respectively. CBs transmitted through an 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) is semi-static signaling (eg, RRC signaling) or dynamic. The terminal may be instructed through signaling (eg, DCI). When receiving DL data, the UE may configure and transmit A / N bits for each CBG.

In addition, method A-3 and the number of symbols constituting one SG or the total number of SGs configured in a TB transmission time interval (and / or the number of RBs constituting one RBG or the total number of RBGs configured in a TB transmission frequency domain) It is also possible to configure CBG to have the same tree structure. Based on nested CBG example 1/2/3, for example, assume that the total number of symbols (or RBs) constituting TB is K = 16, 6, or 9, and each symbol (or RB) is k = 0 to 15 You can index with k = 0 to 5 or k = 0 to 8. In this state, a plurality of SGs (or RBGs) having nested structure relationships with each other may be configured in a form similar to nested CBG example 1/2/3. In addition, the SG (and / or RBG) size / number may be previously defined with the same single value regardless of TBS, or may be predefined with other TB specific values (eg, proportional to TBS).

On the other hand, when one CB is mapped / transmitted over a plurality of SGs (and / or RBGs), the corresponding CBs are Opt 1) SGs having the lowest or highest symbol indices (and / or the lowest or highest RBs). Opt 2) may be defined as being included in the CBG corresponding to the SG (and / or RBG) including the most encoded bits of the CB.

Alternatively, if one CB is mapped / transmitted over multiple SGs (and / or RBGs), the CB may be the corresponding multiple SGs (/ RBGs) in terms of CBG configuration / instruction for (retransmission) scheduling at the base station. It may be set to be included in all of the plurality of CBG corresponding to. On the other hand, from the perspective of configuring the A / N feedback for each CBG in the terminal, the CB is included in only the CBG corresponding to a specific one of the plurality of SGs (/ RBG), and the A / N bits are configured and transmitted for each CBG. can do. In this case, the UE may select one specific CBG including the corresponding CB (when A / N feedback is configured) as follows.

1) If the decoding result of the CB is NACK (of all the multiple CBGs including the CB from the scheduling point of view), if there is a CBG including the CB which is the NACK even if the CB is excluded, (Opt 1/2 One is selected based on the application, and if no such CBG is present, one of all the multiple CBGs (including the corresponding CB in terms of scheduling) may be selected (based on the Opt 1/2 application).

2) Even when the decoding result of the corresponding CB is ACK, one of all the multiple CBGs (including the corresponding CBs in terms of scheduling) may be selected (based on the Opt 1/2 application).

Meanwhile, when a plurality of CBGs including the same CB are scheduled at the same time, the corresponding CBs may operate to be transmitted only once. For example, the CB may be transmitted in a form included only in a specific one of the plurality of CBGs (based on Opt 1/2 application).

By generalizing the above scheme, one CB is set to be commonly included in a plurality of CBGs in terms of CBG configuration / instruction for scheduling of a base station, and a plurality of corresponding CBs are included in view of the UE configuring A / N feedback for each CBG. In the case of operating to include only one specific CBG, the proposed scheme may be applied. For example, when the total K CBs are configured as M CBGs, all CBGs may be set to include the same number of CBs N = ceiling (K / M) CBs per CBG. At this time, some of the CBGs of the M CBGs may be set to include a specific CB in common. For example, within a set of CBGs less than M, any two CBGs may include one CB in common, and the number of CBs commonly included in any two CBGs is a total (M − mod (K, M)).

Alternatively, in order to prevent one CB from being mapped / transmitted over multiple SGs (and / or RBGs), or to match the number of data bits belonging to each CBG as equally as possible between CBGs, May be considered. Assuming that the scheduled TBS is an A bit and the number of SGs or RBGs (generally CBGs) allocated to the TBS is M, first, each CBG (A / M) or ceiling (A / M) or floor (A / M) ) Data bits may be allocated. Next, in the state where the number of data bits allocated for each CBG is replaced with the number of bits Ck corresponding to the TBS in the method X-1 / 2/3, the method X-1 / 2/3 is applied to belong to each CBG. A plurality of CBs can be configured. Meanwhile, the coded bits for a single CBG may be mapped / transmitted to only one SG or RBG.

Meanwhile, a method of changing the number of symbols constituting one SG according to the number of symbols allocated to data transmission and / or the number of RBs (or TBS) is possible. For example, the larger the number of symbols allocated to data transmission (to make the number of CBGs the same as possible), the larger the number of symbols per SG. In addition, the larger the number of RBs (or TBSs) allocated to data transmission (to make the CBG size as same as possible), the smaller the number of symbols per SG. Similarly, a method of changing the number of RBs constituting one RBG according to the number of RBs and / or symbol number (or TBS) allocated to data transmission is possible. For example, the larger the number of RBs allocated for data transmission (to make the number of CBGs as equal as possible), the larger the number of RBs per RBG. In addition, the larger the number of symbols (or TBS) allocated to data transmission (to make the CBG size as same as possible), the smaller the number of RBs per RBG.

5) Method A-5: Configure the total number of CBGs M and CBG size N for each TBS

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

As an additional method, first, a set of (M, N) combinations to be applied for each TBS is referred to as a TBS-CBG table, and one of the plurality of TBS-CBG tables is semi-finished with a plurality of TBS-CBG tables previously defined / set. A method of instructing the UE through static signaling (eg, RRC signaling) or dynamic signaling (eg, DCI) may be considered. In this case, (M, N) combinations corresponding to the same TBS may be configured differently between a plurality of TBS-CBG tables. Accordingly, the terminal determines the (M, N) combination corresponding to the TBS indicated through the DL / UL scheduling DCI with reference to the indicated TBS-CBG table, and based on the determined (M, N) combination, DL / It may be operable to perform UL data transmission and reception and A / N feedback transmission.

Alternatively, a different CBG configuration method may be applied to each TBS range while the entire TBS set is divided into a plurality of TBS ranges. For example, in the TBS range 1, the CBG number M is configured differently (or the same CBG size N) for each method A-1 or TBS, whereas for the TBS range 2, the CBG number M for each method A-2 or TBS is configured. Can be configured in the same way. In this case, in consideration of DCI overhead and / or UCI payload, TBS range 2 may be configured with TBSs larger than TBSs belonging to TBS range 1. In another method, the same CBG configuration (eg, the number / size of CBGs) may be applied to each TBS range, but the number / size of CBGs may be configured differently between the TBS ranges. For example, for each of the TBS ranges 1/2, the number of CBGs M may be identically configured for each method A-2 or TBS, but a different M value may be set between the TBS ranges 1 and 2. In this case, M in TBS range 2 may be set to a value larger than M in TBS range 1. As another example, for each of the TBS ranges 1/2, the CBG size N may be identically configured for each method A-1 or TBS, but a different N value may be set between the TBS ranges 1 and 2. In this case, N in TBS range 2 may be set to a value larger than N in TBS range 1.

6) Method A-6: Interleaving between CBs belonging to the same CBG before data-to-resource mapping

Considering the impact of interference (e.g. URLLC puncturing operation) with a particular (e.g., time-selective) pattern, prior to data-to-resource (e.g., RE) mapping, multiple CBs belonging to the same CBG ( Inter-CB interleaving may be applied between the encoded bits). For example, for a plurality of CBs (coded bits) belonging to one CBG, 1) additionally apply inter-CB interleaving with first applying intra-CB interleaving in each CB, or 2) (CBG-based If the HARQ operation is set, only inter-CB interleaving may be applied while intra-CB interleaving is omitted. Here, the data-to-resource mapping includes, for example, an RE mapping based on a frequency-first manner.

In all the above proposed methods, M, N, and K are set / indicated with the same value for different TBSs, or set / indicated with different values for different TBSs, or some (eg, N) depending on the TBS. The same value may be set / indicated for each of the remaining values (eg, M and K). In addition, when considering a manner in which one DL data scheduling / transmission is performed over a plurality of slots, one symbol set SG may be configured / configured based on the slots in this proposal method. Index is replaced by slot index).

(B) HARQ-ACK feedback method

1) Method B-1: Configure / transmit (minimum) range with all NACKs as feedback on CBG index

Given a CBG configuration scheme (e.g., number / size of CBGs), in consideration of decoding error (i.e., NACK) over successive CBG indexes due to time-selective interference, the UE 1) (on a CBG index) first The NB CBG index and the last NACK CBG index may be fed back to the base station, or 2) the first NACK CBG index and the distance between the first NACK and the last NACK may be fed back. Here, 1) and 2) may be signaled using a resource indication indication (RIV) indication method applied to UL resource allocation type 0 or a combination index method applied to UL resource allocation type 1. In this case, the CBG configuration scheme may include method A-1 / 2/3/4.

As an additional method, the UE directly selects one of a plurality of CBG configuration methods (for example, the number / size of CBGs), and based on the selected CBG configuration, 1) determines a (minimum) CBG range including NACK as described above. The NACK CBG range and the selected CBG configuration information may be fed back to the base station, or 2) the individual A / N bits may be configured for each CBG and fed back to the base station (with the selected CBG configuration information). Even in this case, the CBG configuration scheme may include method A-1 / 2/3/4.

In addition, the method may be applied to CBG scheduling from a base station. Specifically, 1) the first and last CBG indexes to which the (re) transmission will be performed, or 2) the first CBG index and the total number of CBGs L to be (re) transmitted may be indicated through the DL data scheduling DCI. In this case, the UE may 1) schedule a CBG set corresponding to the indexes in between, including the first and last CBG indexes, or 2) CBG sets corresponding to successive L indexes, including the first CBG index. (Receive) can be operated in the assumed / assumed state.

2) Method B-2: Feedback (minimum size) CBG with all NACKs in CBG configuration of tree structure

Given a plurality of CBG configurations (e.g., (M, N) combinations) based on the tree structure as in Method A-3, the UE selects one specific CBG configuration and performs all NACKs based on the selected CBG configuration. By determining a CBG index to be included, the NACK CBG index and the selected CBG configuration information may be fed back to the base station. Here, it may be preferable that the NACK CBG is selected as one CBG including all NACKs and having a minimum size. In other words, the UE first selects a specific CBG configuration such that a single CBG includes all NACKs with a minimum size among a plurality of CBG configurations having a tree structure, and one CBG index including all NACKs based on the selected corresponding CBG configuration. May be determined and fed back to the base station (with the selected CBG configuration information).

Similarly, given a plurality of CBG configurations (based on different SG (/ RBG) sizes / numbers) having a SG (and / or RBG) based tree structure as in Method A-4, The UE selects one CBG configuration based on a specific SG (/ RBG) and determines a CBG index including all NACKs based on the selected CBG configuration, and thus the NACK CBG index and the selected CBG configuration (or corresponding SB ( / RBG) configuration) information is also fed back to the base station.

In addition, the method may be applied to CBG scheduling from a base station. Specifically, given a plurality of CBG configurations (eg, M and / or N (combination), or SG (/ RBG) size / number) having the same tree structure as in method A-3 or A-4, one One CBG index based on the specific CBG configuration of may be indicated through the DL data scheduling DCI. In this case, the UE may operate (receive) in a state where the CBG set belonging to the corresponding CBG index is assumed / regarded as being scheduled through the corresponding DCI.

3) Method B-3: Keep CBG Configuration and Corresponding A / N Configuration the Same During One HARQ Process

To avoid unnecessary RLC level DL data retransmissions due to A / N errors in certain CBGs, one HARQ process is performed (ie, until terminated) (retransmission (CBG) scheduling (indication) at the base station). The A / N feedback configuration corresponding to the CBG configuration and the CBG configuration can be kept the same. Specifically, CBG configuration initially applied / instructed to DL data scheduling / transmission having a specific HARQ process ID and corresponding A / N feedback configuration until the end of the corresponding HARQ process (eg, for all CBs constituting TB of DL data). It may operate to remain the same until successful decoding, or until new DL data scheduling (to which NDI is toggled) starts with the same HARQ process ID. Here, the first applied / instructed CBG and A / N configuration information may be indicated to the terminal through semi-static signaling (eg, RRC signaling) or dynamic signaling (eg, DCI, (initial) DL data scheduling DCI). If the first applied / instructed CBG and A / N configuration information is indicated via semi-static signaling (eg RRC signaling), the CBG and A / N configuration information is fixed statically, until there is a new RRC signaling. It can remain the same in all HARQ processes.

Meanwhile, the UE configures and feeds back A / N bits for each CBG, but may operate to feed back a NACK for the CBG (regardless of whether the corresponding CBG is scheduled) until decoding is successful for each CBG. From the successful decoding, the ACK may be fed back to the CBG (with or without scheduling of the corresponding CBG, and until the end of the corresponding HARQ process).

17 illustrates a signal transmission process for the present invention. FIG. 17 assumes a situation in which the number of CBGs per TB is set to three and TBs are (re) transmitted for the same HARQ process (that is, an operation before the HARQ process corresponding to the TB is terminated).

 Referring to FIG. 17, the terminal may receive CBG # 0 and # 2 from a base station for TB (eg, HARQ process #a) (S1702). Here, the TB of step S1702 may be initial transmission or retransmission corresponding to HARQ process #a. In addition, CBG # 1 assumes that decoding has never been successful before. In this case, the UE transmits A / N information corresponding to three CBGs to the base station (S1704), but sets A / N information for CBG # 1 to NACK, and A / N for CBG # 0 and # 2. The information is set to ACK or NACK according to the decoding result. Thereafter, the base station retransmits the TB (eg, HARQ process #a) in CBG units, and the terminal may receive CBG # 1 and # 2 for the corresponding TB (S1706). In this case, the UE transmits A / N information corresponding to three CBGs to the base station (S1708), but since the decoding was successful, CBG # 0 is set to A / N information for CBG # 0 to ACK. A / N information for CBG # 1 and # 2 is set to ACK or NACK according to the decoding result.

4) Method B-4: Set the corresponding A / N transmission time delay differently according to the number of scheduled CB / CBGs

A / N transmission time delay (that is, time interval between A / N feedback transmissions corresponding to DL data reception) may be differently set according to the number of simultaneously scheduled CBs or CBGs for the same TB (size). . Specifically, the smaller the number of scheduled CBs or CBGs, the smaller the corresponding A / N delay may be set. For example, an A / N delay corresponding to a case where some CBs or CBGs are scheduled may be set smaller than when all TBs, that is, all CBs are scheduled. Also, assuming the same CBG size, the corresponding A / N delay can be set smaller when fewer CBGs are scheduled. In addition, when the number of scheduled CBGs is the same, the corresponding A / N delay may be set smaller when the CBG size is configured smaller.

5) Method B-5: Setting CBG Configuration (CBG Count / Size) Differently Between DL Data Scheduling and A / N Feedback

The CBG configuration (for example, the number / size of CBGs) applied to DL data scheduling / transmission and the CBG configuration applied to A / N feedback corresponding to DL data reception may be differently set. Here, the CBG configuration may 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 may be set to different values. For example, a combination of (M1, N1) may be configured for DL data scheduling, and a combination of (M2, N2) may be configured for A / N feedback. Accordingly, when comparing Case 1 with M1> M2 (and N1 <N2) and Case 2 with M1 <M2 (and N1> N2), Case 1 increases the number of DCI bits while retransmitting DL data resources and A The number of / N feedback bits may be reduced, and in case 2, the number of DCI bits may be reduced while the number of retransmitted DL data resources and A / N feedback bits may be increased.

6) Method B-6: A / N transmission time delay is set differently for each CBG for the scheduled multiple CBGs

A / N transmission time delay may be set differently for each CBG for a plurality of simultaneously scheduled CBGs (that is, TDM transmission of A / N for each CBG). Specifically, the A / N delay corresponding to the CBG transmitted through the lower symbol (or slot) index may be set smaller. Through this, the A / N corresponding to the CBG transmitted through the lower symbol (or slot) index may be fed back through a relatively faster symbol (or slot) timing.

7) Method B-7: A / N Feedback Configuration Corresponding to (Re) Transmission Scheduling in TBs (M of CBGs)

Semi-static signaling (e.g., RRC signaling) or dynamic signaling (e.g., (initial) DL) on whether to perform A / N feedback in A / N bit configuration in TB units or A / N bit configuration in CBG units. The terminal may be instructed through data scheduling DCI). In case of A / N bit configuration in CBG units, the A / N payload size (and the PUCCH format for the corresponding A / N transmission) may be set through semi-static signaling (eg, RRC signaling). In this case, the total number of CBGs constituting the TB may be determined according to a given (fixed) A / N payload size (eg, M bits). For example, the number of CBGs may be determined as M equal to the number of A / N bits. Accordingly, the number of CBGs constituting TB for different TBSs may be set the same, and the number of CBs constituting one CBG may be set differently (eg, in proportion to the TBS) according to the TBS. On the other hand, if the total number of CBs constituting the TB is equal to or smaller than a given A / N payload size, total A / N feedback may be configured by allocating A / N bits for each CB without grouping the CBs. Can be. 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 are allocated for each CB, but 1) the remaining unassigned A / N for each CB (M-N) 2 bits may be processed as NACK, or 2) the A / N payload size may be changed to N (bits) equal to the total number of CBs.

On the other hand, for each TBS, the number of CBs constituting the TB and the CBG configuration (for example, the total number of CBGs constituting the TB, the number of CBs constituting a single CBG) may be determined according to a predetermined rule. In addition, the A / N payload size and the corresponding PUCCH format may be set based on the number of CBGs set in the TB. For example, the PUCCH format and the candidate PUCCH resource set used for CBG unit A / N transmission for each TBS (the total number of CBGs M) may be independently configured (differently). In addition, the M value and / or the corresponding PUCCH format may be indicated to the terminal through semi-static signaling (eg, RRC signaling) or dynamic signaling (eg (DL data scheduling) DCI). For example, a specific combination is indicated through the DCI, or a combination of the M value and the PUCCH format through RRC and / or DCI, with a plurality of combinations of (M value, PUCCH format (and candidate PUCCH resource set)) previously specified. Each of these may be indicated independently. On the other hand, when the M value is indicated, the PUCCH format (and candidate PUCCH resource set) predetermined in advance in the corresponding M value may be automatically determined, or when the PUCCH format is indicated, the M value predetermined in the corresponding PUCCH format may be automatically determined.

Alternatively, the N value and / or the corresponding PUCCH format may be indicated to the terminal via semi-static signaling (eg, RRC signaling) or dynamic signaling (eg (DL data scheduling) DCI). For example, a specific combination is indicated through DCI, or a combination of RRC signaling and / or DCI in a state in which a plurality of N values and a plurality of combinations of (M, PUCCH format (and candidate PUCCH resource set)) are previously specified. Through N value and the PUCCH format can be indicated independently. On the other hand, if the N value is indicated, the PUCCH format (and candidate PUCCH resource set) specified in the M value is automatically determined, or if the PUCCH format is indicated, based on the A / N payload size (eg, M bits) accordingly. The total number of CBGs and the number of CBs per CBG may be automatically determined.

8) Method B-8: A / N feedback configuration corresponding to some CBG (re) transmissions (of M CBGs forming a TB)

When scheduling (re) transmission of L (L <M) or less CBGs among the total M CBGs constituting the TB, the following method may be considered.

Opt 1) The same A / N payload size (eg M bits) as in the case of A / N feedback corresponding to TB (re) transmission (as in method B-7) may be applied. Thus, the actual A / N is mapped to only L bits (corresponding to the rescheduled CBG), and the remaining (M-L) bits (corresponding to the unscheduled CBG) are the same as in Method B-3. ) Depending on the decoding success / failure of the corresponding CBG, it may be mapped to ACK or NACK, or processed as NACK. Opt 2) A / N payload size (and PUCCH format) different from the case of A / N feedback corresponding to TB (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 scheduled number of CBGs. For example, the A / N payload may consist of only L bits.

Here, L may be semi-fixed to one value through semi-static signaling (eg, RRC signaling) or dynamically changed through dynamic signaling (eg, DL data scheduling DCI). In the former case, corresponding CBG indication signaling may be configured to enable scheduling of up to L CBGs among the total M CBGs through scheduling DCI in units of CBGs. In addition, retransmission scheduling (from the base station) may be performed only on L (L <M) or less CBGs among the total M CBGs constituting the TB. In this case, when the number of scheduling target CBGs exceeds L, the base station / terminal may perform scheduling (DCI transmission) / A / N feedback in units of TB.

On the other hand, Opt 1 and Opt 2 basically maintain the same CBG configuration (e.g., the total number of CBGs that make up TB, and the number of CBs that make up a single CBG) for the first time applied / indicated for TB scheduling / transmission. It can be applied assuming.

In addition, for Opt 1, the A / N payload size is set based on TB (re) transmission (e.g., M bits), but only to configure A / N feedback for the actual scheduled CBG. Reconstruct the CBs belonging to the entire L CBGs (each consisting of N CBs) into M CBGs (consisting of fewer Cs than N), based on the total A / Ns according to the A / N bit allocation in CBG units. N feedback may be configured. In this case, the base station may also perform retransmission scheduling assuming M CBGs corresponding to the A / N feedback as the entire CBG set. On the other hand, in a situation in which a CB regrouping process is involved in a terminal corresponding to a DL data receiving end or an A / N transmitting end, when a NACK-to-ACK error occurs, a mismatch between a terminal and a base station for a CBG configuration (performance degradation due to this) ) May be caused. In view of this problem, in addition to A / N information for each M CBG, it additionally includes an indicator (eg, 1-bit) for indicating NACK feedback in TB or not or retransmission request in entire TB. You can configure total A / N feedback (payload). Based on this, when the CBG configuration mismatch occurs, the terminal may map / transmit the indicator to a state corresponding to “TB unit NACK” or “TB retransmission request”. The base station receiving this may perform TB scheduling based on the initial CBG configuration before regrouping.

Meanwhile, in case of CBG retransmission scheduling DCI corresponding to A / N feedback in Opt 2, 1) retransmission CBG indication based on the total number of CBGs regardless of A / N payload size change, 2) UE feedback to NACK Corresponding signaling may be configured in the form of CBG indication under the assumption that one (M or less) CBG set is the entire CBG configuration.

Additionally, whether to apply the same (fixed) same A / N payload size (and PUCCH format) for CBG (retransmission) scheduling, regardless of the number of scheduled CBGs, such as Opt 1, or scheduled CBGs, such as Opt 2 Whether semi-static signaling (e.g. RRC signaling) or dynamic signaling (e.g. (DL data scheduling) DCI) changes whether to apply (dynamically) change of A / N payload size (and PUCCH format) by number It is also possible to instruct the terminal.

9) Method B-9: A / N feedback in units of CBG only when some (of M CBGs forming a TB) are NACK

A / N feedback in units of CBG can be configured / transmitted only when the number of CBGs, which are NACK, out of the total M CBGs constituting the TB is less than or equal to L (L <M) (eg, individual A / N bits are allocated to each CBG). . On the other hand, when the number of CBGs that are NACK exceeds L, it may be configured to configure / transmit A / N feedback in units of TB. In this case, since the CBG unit A / N feedback is configured only for L or less NACKs, the retransmission CBG (index) indication through the CBG unit (retransmission) scheduling DCI is 1) an indication of L or less CBGs out of M totals. Or 2) signaling corresponding to a CBG indication in a state in which the UE assumes (L or less) CBG sets fed back with NACK as the entire CBG configuration. For example, when i = {1, ..., L}, indexing all combinations that select i CBGs among all M CBGs for all i values, and the UE indicates a CBG set that is NACK. One of the indexes may be fed back to the base station.

10) Method B-10: CBG Retransmission Scheduling and A / N Feedback in which the Maximum Number of CBGs is Limited to M

From the base station scheduling point of view, the entire CBG configuration may consist of Mr CBGs (Mr M), and may operate to instruct the UE to retransmit the L CBGs among them (L Mr). Here, M has a fixed value during at least one TB transmission or one HARQ process, while Mr (and L) may change at each (retransmission) scheduling time point.

In this case, the UE may operate as follows in terms of A / N feedback.

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

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

Opt 3) A / N feedback can be configured based on the number of scheduled CBGs. For example, the total A / N payload size may be configured with L bits to map / transmit A / N bits for each scheduled CBG.

In the case of Opt 2/3, the A / N payload size may change according to Mr value or L value, and accordingly, the PUCCH format (and candidate PUCCH resource set) used for A / N feedback transmission may also change. .

Also, in this case, the total Mr CBG configuration for retransmission scheduling at the base station is configured for the entire CB set constituting the TB (that is, the entire CBG set is the same as the entire TB), or is limited to a specific portion of the entire CB. (Ie, the entire set of CBGs corresponds to a portion of the TB). In the former case, for one TB transmission or one HARQ process, the Mr value at a certain scheduling time may be limited to be always set to a value less than or equal to the Mr value at the previous scheduling time. In the latter case, the specific specific CB means 1) a set of CBs belonging to the L CBGs scheduled at the previous scheduling time point, or 2) a set of CBs belonging to the CBGs fed back to the NACK from the UE among the scheduled L CBGs. can do.

11) Method B-11: Processing for Subsequent CBGs Retransmitted Prior to A / N Feedback Transmission

A situation in which CBG retransmission (hereinafter subsequent CBG) for the same TB is scheduled before a transmission of A / N feedback (hereinafter, first A / N) corresponding to a specific TB (hereinafter, referred to as original TB) reception may occur. In this case, the operation of transmitting the A / N feedback reflecting the reception combining for the subsequent CBG through the first A / N time point may be impossible as the decoding end time point for the subsequent CBG becomes too late. In this case, the reception combining may mean an operation of storing a subsequent CBG after emptying (flushing) a buffer in which a previously received signal is stored. In this case, the terminal 1) transmits the A / N feedback according to the decoding result at the first A / N time point only for the original TB and performs reception combining (for A / N feedback at a later time point) for the subsequent CBG. Alternatively, 2) A / N feedback according to the decoding result reflecting the reception combining of subsequent CBGs may be transmitted at a later point in time than the first A / N point in time. In case of 2), A / N transmission may be omitted at the first A / N time point or only A / N for the original TB may be transmitted.

Similarly to the above, in the UL data scheduling situation, (subsequent) CBG retransmission for the same TB may be scheduled before the transmission of a specific (or initial) TB. Here, the original TB transmission time point (hereinafter referred to as TX timing 1) and the subsequent CBG transmission time point (hereinafter referred to as TX timing 2) may be different from each other and may be indicated as a timing point at which TX timing 2 is slower than TX timing 1. In this case, the terminal may transmit only the remaining signals except for the CBG corresponding to the subsequent CBG among the original TB signals scheduled through TX timing 1 (eg, puncturing the RE / RB / symbol to which the corresponding CBG is mapped). With TX timing 2, subsequent CBGs scheduled for retransmission can be transmitted as they are.

Similarly, in the cross-slot scheduling situation for DL data, (subsequent) CBG retransmission for the same TB may be scheduled before a specific (or initial) TB reception. Here, the original TB reception time point (hereinafter referred to as TX timing 1) and the subsequent CBG reception time point (hereinafter referred to as TX timing 2) may be different from each other and may be indicated as a timing point at which TX timing 2 is slower than TX timing 1. In this case, the UE may receive only the remaining signals except for the CBG corresponding to the subsequent CBG among the original TB signals scheduled through TX timing 1 (for example, puncturing the RE / RB / symbol to which the corresponding CBG is mapped). In addition, through TX timing 2, the subsequent CBG scheduled for retransmission can be received as it is.

(C) soft buffer operating method

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

For the (minimum) buffer size Bt per TB allocated to one HARQ process or one TB, the buffer size Bc divided by the sum Cn of the number of CBs belonging to the CBG (s) fed back by the terminal to the (ACK) NACK, A method of determining the minimum buffer size per CB from the terminal reception point may be considered (eg, Bc = Bt / Cn). Specifically, it may be considered to replace 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 UE should store in a buffer for each CB for TB transmission.

In this case, compared with the conventional method based on A / N feedback in TB, there is an advantage that the minimum buffer size per CB can be increased (for example, C> Cn). In addition, Cn applied to one HARQ process or one TB transmission is determined based on 1) only the first A / N feedback (which is NACK CBG) configured in CBG units (that is, Cn equals to the end of the HARQ process). 2) can be determined based on A / N feedback (double NACK CBG) at each time point (ie, Cn is determined according to NACK CBG at every scheduling / feedback time point). ).

Meanwhile, applying Cn of the method C-2 to the Equation 5 (ie, the sum of the number of CBs belonging to the CBG (s) fed back to the NACK from the base station perspective or requiring retransmission (or not receiving the ACK feedback)) You can also consider the method.

2) Method C-2: Rate-Matching Operation (Limited / Circular Buffer) at the Base Station for the Retransmitted CBG Signal

When performing (limited / cyclic buffer) rate-matching with respect to the entire CBG fed back to NACK (from the terminal) or requiring retransmission from the base station perspective, the NACK CBG and the terminal feedback from the base station perspective due to A / N errors Inconsistency may occur between one NACK CBG. To eliminate this discrepancy, the following behavior can be considered.

1) The base station operates to always perform retransmission scheduling at once / simultaneously (ie, retransmission scheduling only for some NACK CBGs) for all CBGs fed back from NACK (or not receiving ACK feedback). Disallowed) (the terminal operates under the assumption / care), or

2) Total CBG information (e.g., NACK CBG counts) that allows the base station to perform retransmission scheduling for only some of the total NACK CBGs but is fed back to NACK or needs retransmission (or failed to receive ACK feedback) from the base station perspective / Index) may be considered an operation of instructing the terminal through the DL data scheduling DCI.

In this case, too, the (minimum) buffer size Bt per TB allocated to one HARQ process or one TB is fed back to the NACK from the base station perspective, or CBG (s) requiring retransmission (or not receiving ACK feedback). The buffer size Bc divided by the total Cn of the number of CBs belonging to may be determined as the minimum buffer size per CB in view of base station transmission (eg, Bc = Bt / Cn). Specifically, it may be considered to replace C with Cn in Equation 2 as follows.

Even at this time, there is an advantage that the minimum buffer size per CB can be increased (for example, since C> Cn) compared with the conventional method of applying only TB retransmission. Cn applied to one TB transmission may be determined based on 1) CBG unit retransmission time point first performed (that is, Cn is applied equally to the end of HARQ process), or 2) CnG unit retransmission time point may be determined (ie, CBG unit retransmission point). Cn is determined based on the number of CBGs fed back to NACK at each time point or requiring retransmission (or not receiving ACK feedback).

On the other hand, when the indication information on the (re) transmitted CBG index and the buffer flush indication information is signaled for each CBG through the data scheduling DCI, signaling of the buffer flush indication information is not supported for the CBG index without the (re) transmission indication. It may not be necessary. Here, the buffer flush information may include indication information on whether to flush the buffer before emptying the received CBG signal to the buffer or to empty the buffer and to combine the CBG signal with the previously stored CBG signal. If the CBG index has no indication of (re) transmission, the UE is instructed to flush and flush the buffer (or vice versa, to combine the buffer without emptying the buffer). It may operate in the assumed / assumed state as CBG which does not require retransmission. On the contrary, if it is instructed to combine without emptying the buffer (or conversely, to flush and empty the buffer), the UE may not perform any operation on the corresponding CBG index (a corresponding reception buffer).

3) Method C-3: Application of Power Offset to A / N Feedback PUCCH Transmission According to Scheduling in CBG Unit

A power offset added / applied to PUCCH transmission carrying A / N feedback configured in CBG units may be determined as a value proportional to the value of Opt 1/2/3/4/5/6/7. Accordingly, as the number of CBGs in Opt 1/2/3/4/5/6/7 increases, the corresponding power offset may be added / applied to a larger value.

Opt 1) The total number of CBGs to which A / N bits are assigned (without distinction between A / Ns) or subject to A / N feedback.

Opt 2) Number of CBGs scheduled from base station

Opt 3) Number of NACK CBGs (at base station) indicated by base station in method C-2

Opt 4) NACK CBG Number in UE

Opt 5) Considering the A / N feedback configuration method as in Method B-3, the sum of the number of CBGs in Opt 2 and the number of CBGs fed back with ACK but not scheduled.

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

Opt 7) The number of CBGs except for CBGs, which have already fed back ACKs to the ACK at the time before that timing

(D) Mismatch handling

1) Method D-1: Inconsistency between A / N information for each CBG fed back by the UE and CBG scheduled for retransmission from the base station

An inconsistency (due to an A / N error) may occur between A / N information for each CBG fed back by the UE and a CBG index scheduled for retransmission from the base station corresponding thereto. For example, there is a possibility that the CBG index scheduled from the base station does not include a part of the CBG fed back by NACK and / or the CBG already fed back by ACK. In this case, the terminal may be set to perform the following operation.

Opt 1) For the CBGs that were previously fed back to NACK among the scheduled CBGs, the decoded A / N results are mapped after combining, or

Opt 2) For the CBGs that were previously fed back to the ACK among the scheduled CBGs (without combining / decoding), map the ACKs again (see Method B-3),

Opt 3) Map NACKs for all CBGs, or

Opt 4) Perform NACK feedback or TB retransmission request in TB units, or

Opt 5) may operate to discard the corresponding CBG scheduling DCI.

On the other hand, if the scheduled CBG includes all of the CBGs previously fed back with NACK, one of Opt 1/2 is applied, and if not, one of Opt 3/4/5 may be applied.

2) Method D-2: Mismatch between CRC applied throughout TB and CRC applied in CB unit and / or CBG unit

The received CRC check result (eg, pass / fail) in the terminal may be different between the CRC applied to the entire TB, the CRC applied in the CB unit, and the CRC applied in the CBG unit. Here, the pass of the CRC check result means that the corresponding data block has been successfully / correctly detected, and the fail of the CRC check result means that the corresponding data block was not successfully / correctly detected.

As an example, the CRC check results in CB and / or CBG units are all pass (i.e., CB CRC based CRC check is pass), whereas the CRC check result of the entire TB may be fail (i.e., TB CRC based CRC check is Fail). Conversely, while the CRC check result of at least one CB and / or CBG unit is a fail (ie, a CB CRC based CRC check is a fail), the CRC check result of the entire TB may be a pass (ie, a TB CRC based CRC check). Pass). In this case, the UE may apply one of Opt 3/4/5 of the method D-1. Opt 3/4/5 of Method D-1 is as follows.

Opt 3) Map NACKs for all CBGs, or

Opt 4) Perform NACK feedback or TB retransmission request in TB units, or

Opt 5) The CBG scheduling DCI may be discarded (discard).

As another example, all of the CB unit CRC check results belonging to one specific CBG are pass, while the CRC check results of the entire CBG may be fail. On the contrary, although at least one CB unit CRC check result belonging to a specific CBG is a fail, the CRC check result of the entire CBG may be a pass. In this case, the UE may feedback by mapping to NACK with respect to the corresponding CBG, or may apply one of Opt 3/4/5 of the method D-1.

(E) CBG scheduling DCI configuration

1) Method E-1: RV Configuration and Setup in CBG Unit Scheduling (DCI)

In the (retransmission) scheduling DCI in CBG units, 1) configure only one RV field with the same size as the RV field in the scheduling DCI in TB units, and apply the indicated RV value equally to the entire scheduled CBG (in this case, the RV value Can be configured in the same manner as in the case of TB scheduling.) 2) Each RB field may be configured for each CBG, but each size may be configured to be smaller than the RV field of the TBI scheduling DCI. May be less than in the case of TB scheduling.

2) Method E-2: Performing Retransmission Scheduling for Some CBGs (of M CBGs constituting TB)

Retransmission scheduling may be performed only for up to L CBGs (L <M) of the total M CBGs constituting the TB. Here, one value of L may be indicated to the terminal through semi-static signaling (eg, RRC signaling). Accordingly, up to L CBGs among the total M CBGs may be indicated through the CBG unit scheduling DCI from the base station, and the TB unit scheduling DCI (or TB unit in the DCI) may be used for retransmission scheduling for more than L CBGs. A flag indicating (re) transmission scheduling) may be applied. Specifically, when i = {1, ..., L}, all combinations that select i CBGs out of the total M CBGs are indexed, and the CBG set / combination corresponding to one of those indexes is scheduled for CBG retransmission. A method of instructing the terminal through the DCI may be considered.

3) Method E-3: Use of NDI Fields in CBG Unit Scheduling (DCI)

The NDI field can be interpreted differently depending on whether it is (re) transmission for the entire TB or for some CBGs (of all CBGs constituting the TB). For example, it may be operable to recognize a combination of toggled NDI bits as scheduling for new data transmission while indicating that all CBGs configuring the TB are transmitted through DCI. Accordingly, a case in which only part of the entire CBG is indicated to be transmitted via DCI may be considered retransmission (not new data), and the NDI field may be used for another specific purpose. As another example, an indicator indicating whether transmission is performed for the entire TB or some CBG through DCI may be directly signaled. In this case, a combination of TB transmission is indicated and a combination of NDI bits toggled can be recognized as scheduling of a new data transmission. Accordingly, the latter case (ie, some CBG transmission indications) may be considered retransmissions and the NDI field may be used for other specific purposes. On the other hand, when the NDI field is used for other specific purposes, the NDI field may include: 1) combining the received CBG signal with a signal previously stored in a reception buffer corresponding to the corresponding CBG index or storing a previously stored signal. It may indicate whether to flush and empty only the received CBG signal (i.e., CBG bufferflush indicator, CBGFI), or 2) (re) transmit CBG (index), (i.e., CBG transmission indicator, CBGTI).

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

The buffer flush indicator field may be interpreted differently in case of data retransmission (without NDI toggling) and in case of new data transmission (with NDI toggling). For example, in case of data retransmission, it may be used to indicate whether to flush or empty the buffer before storing the received CBG signal in the buffer according to the original purpose of the buffer flush indicator (for each CBG). . On the other hand, in the case of new data transmission, the buffer flush indicator may be used for other specific purposes since it basically assumes a buffer flush operation before storing the received signal. When the buffer flush indicator field is used for another specific purpose, the buffer flush indicator field may include a bit indicating TBS and / or MCS information of data to be scheduled. In contrast, the TBS / MCS field may include TBS / MCS information in the DCI scheduling new data transmission, while the TBS / MCS field may include a bit configuring a buffer flush indicator in the DCI scheduling data retransmission.

5) Method E-5: Use of CBGTI (and CBGFI) Fields in CBG Unit Scheduling (DCI)

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

First, with only the CBGTI field configured (or CBG mode 1 in the DCI) (without a separate CBGFI field configuration) (hereinafter, CBG mode 1), all bits constituting the corresponding CBGTI field will be indicated as "0". Can be. In this case, the (terminal) may define / refer that the buffer flush operation for all CBGs is indicated while the (re) transmission is indicated for all CBGs constituting a given TB. Accordingly, the terminal may operate to store the newly received CBG signal in the buffer after flushing the signal previously stored in the buffer. On the other hand, in CBG mode 1 (when NDI is not toggled), all bits constituting the CBGTI field may be indicated as "1". In this case, the (terminal) may define / refer that the (re) transmission is indicated for all CBGs constituting a given TB without a buffer flush operation.

Next, in a state in which both the CBGTI field and the CBGFI field are configured / set in the DCI (hereinafter, CBG mode 2), all bits constituting the CBGTI field (NDI is not toggled) may be indicated as "0". In this case, the (terminal) may define / refer that the (re) transmission is indicated for all CBGs constituting a given TB. In this state, in addition, in case 1) the CBGFI bit is indicated as "0", the (terminal) can be defined / recognized as indicated that the buffer flush operation is indicated for certain CBG (hereinafter, CBG sub-group1) Case 2) When the CBGFI bit is indicated as "1", it may be defined / represented that a buffer flush operation is indicated for another specific some CBG (hereinafter, CBG sub-group2). The CBG (s) belonging to the CBG sub-group1 and the CBG sub-group2 may be configured completely exclusively or partially identical to each other (although the union of the CBGs is the entire CBG set). On the other hand, in CBG mode 2 (when NDI is not toggled), when all bits constituting the CBGTI field are indicated by "1" and the CBGFI bit is indicated by "1" (or "0"), Can be defined / remembered that the buffer flush operation for all CBGs is indicated (or not indicated) while the (re) transmission is indicated for all CBGs constituting a given TB.

On the other hand, in consideration of early termination of the TB decoding operation in the UE, 1) sequentially decoding CBs one by one for each CBG alternately for a plurality of CBGs (for example, CB1 in CBG-1 => CB1) in CBG-2 => ... CB1 in CBG-M => CB2 in CBG-1 => ... to perform decoding in the same order), 2) Decoding in CBG sequentially for each CBG (on index) (E.g., decoding in the order CBs in CBG-1 => CBs in CBG-2 => ...). If a CBG that is a NACK occurs, skip the decoding operation for all CBGs (indexes) after that. NACK can be fed back.

Meanwhile, for DL / UL data transmitted based on the SPS scheme, retransmission scheduling by CBG unit and A / N feedback configuration operation for each CBG may not be applied / set. Accordingly, retransmission scheduling in CBG units and A / N feedback configuration operations for each CBG units may be applied / configured only for general scheduling-based DL / UL data transmission and not for SPS, and in units of TB for SPS-based DL / UL data transmission. Scheduling and per TB (ie TB level) A / N feedback (eg, configuring / sending 1-bit A / N for one TB) may be applied / set. In addition, transmission of a terminal (group) CSS-based DCI (or TM-common DCI format in a form similar to (commonly set / used for different TMs) similar to DCI format 0 / 1A in LTE, for example, LTE) Retransmission scheduling in CBG units and A / N feedback for each CBG for DL / UL data (and / or Msg3 scheduled for RSO involved in random access procedure and Msg4 transmitted for contention resolution purposes) scheduled through The configuration action may not be applied / set. Accordingly, CBG-based retransmission scheduling and A / N feedback configuration operation only for DL / UL data transmission scheduled through USS based DCI (or TM-only DCI format that is set / used only for a specific TM) rather than CSS. This can be applied / set. In contrast, DL / UL data (and / or Msg3 / 4) transmissions scheduled through CSS-based DCI (or TM-common DCI format) transmission are applied by TB scheduling and TB (TB level) A / N feedback operation. / May be set (ie configure TB level A / N feedback).

Meanwhile, in a situation in which retransmission scheduling by CBG unit and A / N feedback configuration operation for each CBG are set, for the same reason as described above (or for other reasons, for example, the UE may perform A / N per CBG to reduce A / N payload). If bundling or A / N bundling operation is indicated from the base station) to configure TB level A / N feedback, (case 1) transmit only A / N for a single TB without multiplexing, or (case 2) multiple TBs. The A / N method may vary depending on whether multiple A / Ns are transmitted by multiplexing. For example, in case 1, only 1-bit A / N payload is configured, and then A / N can be transmitted using a PUCCH format / resource supporting small payload (eg, up to 2 bits). have. On the other hand, in case 2, when the number of CBGs per TB is set to N, Opt 1) repeatedly maps A / N for TB to the corresponding N bits, or Opt 2) specifies A / N for TB. For example, lowest) may be mapped to 1-bit corresponding to the CBG index. Opt 1) and Opt 2) may be applied irrespective of case 2 in a situation in which retransmission scheduling in CBG units and A / N feedback configuration for each CBG are set.

In case 2, the UE configures a multi-bit A / N payload including N-bit A / N corresponding to the corresponding TB to support a large payload (eg, 3 bits or more). A / N can be transmitted as a resource. The multi-bit A / N payload may include A / N information corresponding to a plurality of TBs. For example, the multi-bit A / N payload may include a plurality of N-bit A / Ns corresponding to a plurality of TBs.

On the other hand, when the intentional URLLC puncturing operation described above is applied in a co-channel inter-cell environment, at least a DMRS signal in which a URLLC signal transmitted in one cell is used to receive DL / UL data in another cell is used. It may be desirable to minimize the impact of interference on the system. To this end, an operation of transferring / 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.

The proposed methods of the present invention may not be limited to DL data scheduling and transmission situations, and may be equally or similarly applied to UL data scheduling and transmission situations (eg, 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).

18 illustrates a base station and a terminal that can be applied to the present invention.

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

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 with 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 by the present invention. The memory 124 is connected with the processor 122 and stores various information related to the operation of the processor 122. The RF unit 126 is connected with the processor 122 and transmits and / or receives a radio signal.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the 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 obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

In this document, embodiments of the present invention have been described mainly based on a signal transmission / reception relationship between a terminal and a base station. This transmission / reception relationship is extended to the same / similarly for signal transmission / reception between the terminal and the relay or the base station and the relay. Certain operations described in this document as being performed by a base station may, in some cases, be performed by their uppernodes. That is, it is obvious that various operations performed for communication with the terminal in a network including a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. In addition, the terminal may be replaced with terms such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), and the like.

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

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

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

Claims (14)

1. In a method for transmitting a HARQ-ACK (Hybrid ARQ Acknowledgement) information on a Code Block Group (CBG) -based basis in a wireless communication system,

   Performing decoding on CBGs constituting a transport block (TB);

   After the decoding, receiving the TB again; And

   Transmitting a plurality of HARQ-ACK bits for re-receipt of the TB, each HARQ-ACK bit including a HARQ-ACK response for each CBG of the TB;

   Of the plurality of HARQ-ACK bits, the HARQ-ACK bit for the first CBG successfully decoded before re-receipt of the TB is mapped to ACK regardless of whether the first CBG is received when the TB is re-received. Way.
2. The method of claim 1,

   Wherein the first CBG comprises unreceived CBG upon re-receipt of the TB.
3. The method of claim 1,

   The HARQ-ACK bit for the second CBG that is not received upon re-reception of the TB among the plurality of HARQ-ACK bits and not successfully decoded before re-receipt of the TB is mapped to NACK (Negative ACK).
4. The method of claim 1,

   Wherein each CBG comprises one or more CBs, each CB is appended with a CB-based Cyclic Redundancy Check (CRC), and the TB is appended with a TB-based CRC.
5. The method of claim 1,

   The total number M of CBGs constituting the TB is received through Radio Resource Control (RRC) signaling, and the plurality of HARQ-ACK bits is M.
6. The method of claim 1,

   TB of the decoding process and TB of the re-receipt process share the same HARQ process.
7. The method of claim 1,

   Wherein the wireless communication system is ^{3GPP (3 rd Generation Partnership Project)} - comprises a base radio communication systems.
8. In a communication device used to transmit Hybrid ARQ Acknowledgement (HARQ-ACK) information on a Code Block Group (CBG) -based basis in a wireless communication system,

   RF (Radio Frequency) module; And

   A processor, wherein the processor,

   Decode the CBGs constituting the TB (Transport Block),

   After the decoding, the TB is received again,

   Transmit a plurality of HARQ-ACK bits for re-receipt of the TB, each HARQ-ACK bit is configured to indicate a HARQ-ACK response for each CBG of the TB,

   Of the plurality of HARQ-ACK bits, the HARQ-ACK bit for the first CBG successfully decoded before re-receipt of the TB is mapped to ACK regardless of whether the first CBG is received when the TB is re-received. Communication device.
9. The method of claim 8,

   And the first CBG comprises an unreceived CBG upon re-receipt of the TB.
10. The method of claim 8,

    The HARQ-ACK bit for the second CBG unreceived upon re-reception of the TB of the plurality of HARQ-ACK bits and not successfully decoded before re-receipt of the TB is mapped to NACK (Negative ACK).
11. The method of claim 8,

    Each CBG includes one or more CBs, each CB is appended with a CB-based Cyclic Redundancy Check (CRC), and the TB is appended with a TB-based CRC.
12. The method of claim 8,

    The total number M of CBGs constituting the TB is received through Radio Resource Control (RRC) signaling, and the plurality of HARQ-ACK bits is M.
13. The method of claim 8,

    The TB of the decoding process and the TB of the re-receipt process share the same HARQ process.
14. The method of claim 8,

    Wherein the wireless communication system is ^{3GPP (3 rd Generation Partnership Project)} - based communication device including the wireless communication system.

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