KR102291796B1 - Repetition transmission method based on code block group for ultra-reliable and low latency communication in a wireless communication system and apparatus thereof - Google Patents

Abstract

Provided are a code block group (CBG)-based transmission method for ultra-low latency and high reliability communication in a wireless communication system and an apparatus therefor. A method for a terminal to transmit data in a wireless communication system includes the steps of receiving feedback on uplink data transmitted by the terminal from a base station, determining whether to retransmit the uplink data based on the feedback, and the uplink When data is retransmitted, setting the size of a code block group of the uplink data based on the type of uplink data, and retransmitting the uplink data in units of the adjusted code block group. can

Description

CBG-based transmission method for ultra-low-latency, high-reliability communication in a wireless communication system and an apparatus therefor

The present invention relates to a method and apparatus for transmitting data in a wireless communication system, and more particularly, to a method and apparatus for transmitting data based on a code block group for ultra-low latency and high reliability communication. .

For communication in various application fields corresponding to the 5G URLLC (Ultra-Reliable and Low Latency Communication) communication scenario, data needs to be transmitted quickly and stably. However, when the terminal moves in a direction in which the channel deteriorates in an environment in which the terminal moves rapidly, an error may occur when the base station sets and transmits the transmission format based on the CQI (channel quality indicator) fed back to the base station by the corresponding terminal. , this may cause a situation in which the data needs to be retransmitted.

In the case of transmitting general data, there is no problem even if data is retransmitted. However, in the case of transmitting URLLC data, if retransmission occurs, a problem of increasing latency may occur. URLLC data generally has a smaller data transmission size than eMBB (enhanced　mobile　Broad Band) data. Therefore, the unit for retransmitting URLLC data also needs to be smaller than that of eMBB data.

An object of the present invention is to provide a method for transmitting data based on a code block group (CBG) in a scenario such as URLLC in which the amount of data is relatively small and data must be transmitted stably and with a short delay.

Another technical object of the present invention is to provide an apparatus for transmitting data based on CBG in a scenario such as URLLC in which the amount of data is relatively small and data must be transmitted stably and with a short delay.

According to an aspect of the present invention, a method for a terminal to transmit data in a wireless communication system includes receiving feedback on uplink data transmitted by the terminal from a base station, and whether the uplink data is retransmitted based on the feedback determining, when retransmitting the uplink data, setting the size of a code block group of the uplink data based on the type of the uplink data, and the uplink in units of the adjusted code block group It may include retransmitting the data.

According to one side, the uplink data includes URLLC (Ultra-Reliable and Low Latency Communication) data, and the size of the code block group is greater than the size of the code block group for retransmission of enhanced mobile broadband (eMBB) data. It can be set small.

According to another aspect, before the receiving step, the size of a code block group for retransmission of the URLLC data from the base station through at least one of a radio resource control (RRC) message and downlink control information. The method may further include receiving information.

According to another aspect, the information on the size of the code block group may be information on the maximum number of code block groups per transport block for the URLLC data.

According to another aspect, the maximum number of code block groups per transport block for the URLLC data may be set separately from the maximum number of code block groups per transport block for the eMBB data.

According to another aspect of the present invention, a method for a base station to transmit data in a wireless communication system includes receiving feedback on downlink data transmitted by the base station from a terminal, and whether the downlink data is retransmitted based on the feedback determining, when retransmitting the downlink data, setting the size of a code block group of the downlink data based on the type of the downlink data, and the downlink in units of the adjusted code block group It may include retransmitting the data.

According to the present invention, when URLLC data is retransmitted by HARQ, a time delay can be reduced, and retransmission can be performed more efficiently in terms of resource allocation and resource use required for transmission.

1 is a conceptual diagram illustrating a wireless communication system according to an embodiment of the present invention.
2 is an exemplary diagram illustrating an NR system to which a data transmission method according to an embodiment of the present invention can be applied.
3 is a diagram illustrating a slot structure used in a data transmission method according to an embodiment of the present invention.
4 is a diagram for explaining a mini-slot used in a data transmission method according to an embodiment of the present invention.
5 is a diagram for explaining the concept of a code block group applied to the present invention.
8 is a diagram for explaining a case of retransmitting eMBB data according to an embodiment.
9 is a diagram for explaining a case of retransmitting URLLC data according to an embodiment.
10 is a flowchart illustrating a data transmission method according to an embodiment of the present invention.
11 is a block diagram illustrating a wireless communication system in which an embodiment of the present invention is implemented.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements.

In this specification, terms such as “first”, “second”, “A”, “B”, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term "and/or" also includes combinations of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is mentioned that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, terms used herein have the same meanings as commonly understood by those of ordinary skill in the art to which the present invention belongs, including technical or scientific terms. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 1 , a wireless communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3. , 130-4, 130-5, 130-6).

Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the plurality of communication nodes is a CDMA (Code Division Multiple Access) based communication protocol, WCDMA (Wideband CDMA) based communication protocol, TDMA (Time Division Multiple Access) based communication protocol, FDMA (Frequency Division Multiple) Access) based communication protocol, OFDM(Orthogonal Frequency Division Multiplexing) based communication protocol, OFDMA(Orthogonal Frequency Division Multiple Access) based communication protocol, SC(Single Carrier)-FDMA based communication protocol, NOMA(Non-Orthogonal Multiplexing) Access)-based communication protocol, space division multiple access (SDMA)-based communication protocol, etc. may be supported.

The wireless communication system 100 includes a plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 and a plurality of user equipments 130-1, 130-2, 130-3, 130-4, 130-5, 130-6).

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong within the coverage of the third base station 110-3. . The first terminal 130-1 may belong to the coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB, an evolved NodeB, and a next generation Node B (NodeB). B, gNB), BTS (Base Transceiver Station), radio base station (radio base station), radio transceiver (radio transceiver), access point (access point), access node (node), road side unit (RSU), DU (Digital Unit), CDU (Cloud Digital Unit), RRH (Radio Remote Head), RU (Radio Unit), TP (Transmission Point), TRP (transmission and reception point), to be referred to as a relay node (relay node), etc. can Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is a terminal, an access terminal, a mobile terminal, It may be referred to as a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, and the like.

A plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6) each of which may support a cellular (cellular) communication (for ^{example, 3GPP (3 rd generation partnership project} ) standard, LTE (long term evolution), LTE-a (advanced), NR (new Radio) defined by, and so on). Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul or a non-ideal backhaul, and the ideal backhaul Alternatively, information may be exchanged with each other through a non-ideal backhaul. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to a core network (not shown) through an ideal backhaul or a non-ideal backhaul. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminals 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is transmitted to the core network can be sent to

Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may support OFDMA-based downlink transmission, and OFDMA or SC-FDMA-based uplink transmission. (uplink) transmission may be supported. In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits multiple input multiple output (MIMO) (eg, single user (SU)-MIMO, MU (Multi User)-MIMO, massive MIMO, etc.), Coordinated Multipoint (CoMP) transmission, carrier aggregation transmission, transmission in an unlicensed band, direct device to device, D2D) communication (or Proximity Services (ProSe)) may be supported, etc. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 Base stations 110-1, 110-2, 110-3, 120-1, 120-2 and corresponding operations and/or base stations 110-1, 110-2, 110-3, 120-1, 120-2 ) can perform operations supported by .

For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO method, and the fourth terminal 130-4 may transmit a signal based on the SU-MIMO method. A signal may be received from the second base station 110 - 2 . Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO scheme, and the fourth terminal 130-4. and each of the fifth terminals 130 - 5 may receive a signal from the second base station 110 - 2 by the MU-MIMO method. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and the fourth The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 includes the terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6) and a signal may be transmitted/received based on the CA method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 coordinates D2D communication between the fourth terminal 130-4 and the fifth terminal 130-5. (coordination), each of the fourth terminal 130-4 and the fifth terminal 130-5 is D2D communication by the respective coordination of the second base station 110-2 and the third base station 110-3 can be performed.

Hereinafter, even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a second communication node corresponding thereto corresponds to the method performed in the first communication node A method (eg, receiving or transmitting a signal) may be performed. That is, when the operation of the terminal is described, the corresponding base station may perform the operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, the corresponding terminal may perform the operation corresponding to the operation of the base station.

Also, hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In the downlink, the transmitter may be a part of the base station, and the receiver may be a part of the terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the base station.

Recently, as the spread of smartphones and Internet of Things (IoT) terminals is rapidly spreading, the amount of information exchanged through a communication network is increasing. Accordingly, in the next-generation wireless access technology, an environment that provides a faster service to more users than the existing communication system (or the existing radio access technology) (eg, enhanced mobile broadband communication) ) needs to be considered.To this end, the design of a communication system in consideration of MTC (Machine Type Communication) that provides a service by connecting a plurality of devices and objects is being discussed. The design of a communication system (eg, URLLC (Ultra-Reliable and Low Latency Communication)) considering a service and/or a terminal sensitive to reliability and/or latency is also being discussed.

Hereinafter, in this specification, for convenience of description, the next-generation radio access technology is referred to as a New Radio Access Technology (RAT), and a wireless communication system to which the New RAT is applied is referred to as a New Radio (NR) system.

2 is an exemplary diagram illustrating an NR system to which a data transmission method according to an embodiment of the present invention can be applied.

2, Next Generation-Radio Access Network (NG-RAN) is a control plane (RRC) protocol for the NG-RA user plane (new AS sublayer/PDCP/RLC/MAC/PHY) and UE (User Equipment) It consists of gNBs that provide termination. Here, NG-C represents a control plane interface used for an NG2 reference point between NG-RAN and 5GC (5 Generation Core). NG-U represents the user plane interface used for the NG3 reference point between NG-RAN and 5GC.

gNBs are interconnected through the Xn interface, and connected to the 5GC through the NG interface. More specifically, the gNB is connected to an Access and Mobility Management Function (AMF) through the NG-C interface and to a User Plane Function (UPF) through the NG-U interface.

In the NR system of FIG. 2, multiple numerologies may be supported. Here, the numerology may be defined by a subcarrier spacing and a cyclic prefix (CP) overhead. In this case, a plurality of subcarrier intervals may be derived by scaling the basic subcarrier interval by an integer. Also, although it is assumed that very low subcarrier spacing is not used at very high carrier frequencies, the numerology used can be selected independently of the frequency band.

In addition, in the NR system, various frame structures according to a number of numerologies may be supported. Hereinafter, OFDM numerology and a frame structure used in a data transmission method according to an embodiment of the present invention will be described with reference to FIG. 3 .

3 is a diagram illustrating a slot structure used in a data transmission method according to an embodiment of the present invention.

A Time Division Duplexing (TDD) structure considered in the NR system is a structure in which both uplink (UL) and downlink (DL) are processed in one slot (or subframe). This is to minimize the latency of data transmission in the TDD system, and may be referred to as a self-contained structure or a self-contained slot.

Referring to FIG. 3 , one slot may consist of 14 OFDM symbols. In FIG. 3, region 310 indicates a downlink control region, and region 320 indicates an uplink control region. Areas other than the areas 310 and 320 (ie, areas without a separate indication) may be used for transmission of downlink data or uplink data. That is, the uplink control information and the downlink control information may be transmitted in one slot. On the other hand, in the case of data, uplink data or downlink data may be transmitted in one slot.

When the structure shown in FIG. 3 is used, downlink transmission and uplink transmission are sequentially performed within one slot, and transmission of downlink data and reception of uplink ACK/NACK may be performed. Accordingly, when an error in data transmission occurs, the time required until data retransmission can be reduced. In this way, the delay associated with data transmission can be minimized.

In the slot structure as shown in FIG. 3, a time gap is required for the process of the base station and/or the terminal switching from the transmission mode to the reception mode or the process of switching from the reception mode to the transmission mode. do. With respect to the time difference, when uplink transmission is performed after downlink transmission in the slot, some OFDM symbol(s) may be set as a guard period (GP).

4 is a diagram for explaining a mini-slot used in a data transmission method according to an embodiment of the present invention.

According to an embodiment of the present invention, in addition to the slot-based scheduling for efficient support for URLLC, mini-slot-based scheduling may be supported. A mini-slot is a minimum scheduling unit by a base station, and may be composed of, for example, 2, 4, or 7 OFDM symbols.

A mini-slot may be started in any OFDM symbol in the slot as shown in FIG. 4 . In FIG. 4 , two mini-slots having different lengths (the number of OFDM symbols) are shown in one slot, but this is for illustrative purposes only. When a plurality of mini-slots are included in one slot, each mini-slot is The number of OFDM symbols constituting ? may be the same.

In the NR system, for communication in various application fields corresponding to V2X (Vehicle to Everything) and URLLC scenarios, there is a need for data to be transmitted stably and quickly with almost no errors. In particular, when the terminal moves in a direction in which the channel deteriorates in an environment in which the terminal moves rapidly, an error may occur when the base station sets the transmission format and transmits data based on the CQI fed back to the base station by the corresponding terminal. It is very likely that there will be situations in which In the case of transmitting general data such as eMBB (enhanced　mobile　Broad Band) data, there is no problem even if retransmission occurs.

Therefore, in order to achieve high reliability and low latency of data in the URLLC communication scenario, a method different from that of eMBB data transmission should be applied.

5 is a diagram for explaining the concept of a code block group applied to the present invention.

In the NR system, retransmission due to HARQ is performed in units of a code block group (CBG), which is a unit smaller than a unit of a transport block (TB). As an example, referring to FIG. 5 , one TB may be segmented into eight code blocks (CBs), and three code blocks may be grouped into one CBG. However, this is only an example, and one CBG may be configured by one code block, and one TB may be configured by one CBG.

6 is a diagram illustrating a configuration of a PDSCH serving cell applied to an embodiment of the present invention, and FIG. 7 is a diagram illustrating a configuration of a PUSCH serving cell applied to an embodiment of the present invention.

6 and 7, a maximum of 2, 4, 6, or 8 CBGs per one TB may be configured by higher layer signaling in both uplink transmission and downlink transmission. CBG is a group of 2, 4, 6, 8 code blocks, used as a unit of HARQ retransmission, and reflected in DCI.

DCI format 0_1 used for PUSCH scheduling is shown in Table 1 below, and DCI format 1_1 used for PDSCH scheduling is shown in Table 2 below.

Field Bits Usage Identifier for DCI formats One 0 is set for UL DCI carrier indicator 0 or 3 UL/SUL indicator 0 or 1 1 bit if UE is configured with SUL, 0 otherwise Bandwidth part indicator 0, 1, or 2 Frequency domain resource assignment variable Time domain resource assignment 0, 1, 2, 3, or 4 frequency hopping flag 0 or 1 0 when frequency hopping not enabled, else 1 Modulation and coding scheme 5 new data indicator One Redundancy version 2 HARQ process number 4 1 ^st downlink assignment index 1 or 2 2 ^nd downlink assignment index 0 or 2 TPC command for scheduled PUSCH 2 SRS resource indicator variable Precoding information and number of layers variable Antenna ports variable CSI request 0, 1, 2, 3, 4, 5, or 6 CBG transmission information 0, 2, 4, 6, or 8 Determined by higher layer parameter maxCodeBlockGroupsPerTransportBlock PTRS-DMRS association variable Beta_offset indicator 0 or 2 0 if betaOffset = semestatic, 2 otherwise DMRS sequence initialization 0 or 1 0 bit if the higher layer parameter transform precoder is enabled1 bit if he higher layer parameter transform precoder is disabled UL-SUH indicator One

Field Bits Usage Identifier for DCI formats One value as 1, indication of DL DCI carrier indicator 0 or 3 Bandwidth part indicator 0, 1, or 2 Frequency domain resource assignment variable Similar to DCI 1_0 field Time domain resource assignment 0, 1, 2, 3, or 4 VRB-to-PRB mapping 0 or 1 0 if prb-BundingType is not configured or is set to static, 1 otherwise PRB bundling size indicator 0 or 1 Rate matching indicator 0, 1, or 2 ZP CSI-RS trigger 0, 1, or 2 Modulation and coding scheme [TB1] 5 New data indicator [TB1] One Redundancy version [TB1] 2 Modulation and coding scheme [TB2] 5 New data indicator [TB2] One Redundancy version [TB2] 2 HARQ process number 4 Downlink assignment index 0, 2, or 4 TPC command for scheduled PUSCH 2 PUCCH resource indicator 3 PDSCH-to-HARQ_feedback timing indicator 0, 1, 2 or 3 Antenna ports 4, 5, or 6 SRS request 2 CBG transmission information 0, 2, 4, 6, or 8 CBG flushing out information 0 or 1 DMRS sequence initialization 0 or 1

However, since URLLC data generally has a smaller data size than eMBB data and requires low latency, the unit (or size) of CBG needs to be set to a unit smaller than that of eMBB. Therefore, according to the present embodiment, a CBG for URLLC purpose may be set separately from CBG for eMBB use. As an example, CBG for URLLC may consist of 1, 2, 3 or 4 code blocks. Alternatively, in the case of URLLC, the maximum number of CBGs included in one TB may be set to 4, 8, 12 or 16. That is, when URLLC data is retransmitted, the maximum number of CBGs included in the TB is determined according to the TB size, and as a result, the size unit of the retransmitted data may be set smaller than that of the eMBB.

For example, in the case of URLLC, if the TB size is the same as the eMBB, the maximum number of CBGs per TB for the URLLC may be set to be larger than the eMBB. If the TB size is smaller than the eMBB, the maximum number of CBGs per TB for URLLC may be set similarly to the eMBB. That is, according to an embodiment, the maximum number of CBGs per TB for URLLC may be set by RRC separately from the maximum number of CBGs per TB for eMBB.

Information on CBG for URLLC may be indicated by RRC, and if necessary, DCI settings may be changed or added to reflect this. As an example, a field for CBG transmission information for URLLC may be added to DCI format 0_1 of Table 1 and/or DCI format 1_1 of Table 2 . For example, the CBG transmission information for the URLLC is set to any one of 0, 2, 4, 6, 8, 10, 12, 14, or 16 bits, and indicates that the CBG is to be retransmitted when the URLLC data is retransmitted in the form of a bitmap. can be directed to

Meanwhile, as RRC, the maximum number of CBGs per TB for URLLC may be set separately from the maximum number of CBGs per TB currently set for eMBB (2, 4, 6, 8). As an example, the maximum number of CBGs per TB for URRLC may be configured in the RRC message of FIGS. 6 and/or 7 .

Also, {n1, n2, n4, n8} may be added as information on the number of CBs (CodeBlocksPerCodeBlockGroup for URLLC) per CBG. As another example, {n4, n8, n12, n16} may be added to the RRC message of FIGS. 6 and/or 7 as information on the maximum number of CBGs (maxCodeBlockGroupsPerTransportBlock for URLLC) per TB for URRLC.

As another example, instead of separately setting the CBG for URLLC as RRC, if the data corresponds to URLLC, the maximum number of CBGs per TB (2, 4, 6, 8) is separately recognized as (4, 8, 12, 16). It can be mapped to a table for URLLC of For example, if the number of CBGs per TB for eMBB data is set to '2' by the base station, the UE sets the number of CBGs per TB to '4' for URLLC data based on information set in the ULLC table to 4 Among the CBGs, only the CBG including the data in which the error occurred may be retransmitted.

When this method is applied, the retransmission time of URLLC data by HARQ can be reduced, and retransmission of URLLC data having a relatively small data size can be performed more efficiently.

8 is a diagram illustrating a case of retransmitting eMBB data according to an embodiment, and FIG. 9 is a diagram illustrating a case of retransmitting URLLC data according to an embodiment.

First, referring to FIG. 8 , a case in which one TB is configured with two CBGs and one CBG includes four CBs is illustrated. When initially transmitting eMBB data, since the transmitter performs transmission in TB units, CBs #0 to CB #7 are transmitted to the receiver. In this case, when an error occurs in at least one of CB #0 to CB #3 and the HARQ NACK for CBG#1 is received, the transmitter retransmits only CBB#1. On the other hand, as shown in FIG. 9 , when the CBG (CBG#1) including the CB in which the error occurred in the same situation as in FIG. 8 corresponds to the URLLC data, the transmitter sets the CBG to a size smaller than the size of the CBG for the eMBB data. can be configured to retransmit the data. To this end, the transmitter may increase the number of CBGs per TB when retransmitting URLLC data to increase the number of CBGs in the initially transmitted TB or decrease the number of CBs per CBG. Therefore, according to the present embodiment, since the URLLC data can be retransmitted in a smaller unit than the case of retransmitting the eMBB data, retransmission with lower delay and higher efficiency is possible.

10 is a flowchart illustrating a data transmission method according to an embodiment of the present invention.

Hereinafter, a method for a transmitter to transmit data to a receiver according to the present embodiment will be described with reference to FIG. 10 . In this embodiment, when the transmitter is a base station, the receiver may be a terminal, and when the transmitter is a terminal, the receiver may be a base station or another terminal. When the receiver is a base station, the data may be referred to as URLLC data, uplink data, PUSCH or PUSCH data. When the receiver is another terminal, the data may be referred to as URLLC data, sidelink data, PSSCH or PSSCH data. When the transmitter is a base station, the data may be referred to as URLLC data, downlink data, PDSCH or PDSCH data.

For example, when the transmitter is a terminal and the receiver is a base station, the terminal transmits uplink data to the base station (S1010) and receives feedback on the uplink data from the base station (S1020). Here, the feedback may be HARQ ACK or HARQ NACK for the uplink data.

The terminal may determine whether to retransmit the uplink data based on the feedback (S1030). If the feedback for the uplink data transmitted to the base station is ACK, the terminal determines that the corresponding data has been successfully transmitted and omits retransmission of the corresponding data. That is, the data is not retransmitted. However, if NACK is included in the feedback, the UE may retransmit the corresponding data. In this case, the UE may adjust the size of the CBG of the uplink data based on the type of uplink data requiring retransmission, and may perform retransmission in the adjusted CBG unit. For example, if the data corresponding to the NACK is eMBB data, the terminal may retransmit the CGB including the code block in which the error occurs as shown in FIG. 8 to the base station. However, if the data corresponding to the NACK is URLLC data, the UE may adjust the size of the CBG as shown in FIG. 9 ( S1040 ) and perform retransmission based on the adjusted CGB ( S1050 ). In this case, the size of the CBG for retransmission of the URLLC data may be set smaller than the size of the CBG for retransmission of the eMBB data so that the URLLC data can be transmitted faster with fewer resources. Information about this (information on the size of CBG for retransmission of URLLC data) may be received from the base station through at least one of an RRC message and/or DCI. In this case, the code block group for retransmission of eMBB data includes 2, 4, 6, or 8 code blocks, and the code block for retransmission of the URLLC data includes 1, 2, 3 or 4 code blocks. It can contain multiple code blocks.

As another example, when the transmitter is the base station and the receiver is the terminal, the base station determines whether to retransmit the data based on the feedback on the downlink data transmitted to the terminal is received from the terminal. If the feedback is ACK, the base station determines that the corresponding data has been successfully transmitted and transmits the next data. However, if NACK is included in the feedback, the base station may adjust the size of the CBG based on the type of the corresponding data and perform retransmission in the adjusted CBG unit. For example, when the data corresponding to the NACK is eMBB data, the base station may retransmit the CGB including the code block in which the error occurs as shown in FIG. 8 to the terminal. However, when the data corresponding to the NACK is URLLC data, the base station may adjust the size of the CBG as shown in FIG. 9 ( S1040 ) and perform retransmission based on the adjusted CGB ( S1050 ). In this case, the base station may transmit information on the size of the CBG for retransmission of URLLC data to the terminal through DCI. Alternatively, information on the size of a CBG for retransmission of the URLLC data may be transmitted to the terminal in advance through an RRC message. Here, the information on the size of CBG for retransmission of the URLLC data may be information on the maximum number of code block groups per TB for URLLC data, and information on the number of maximum code block groups per TB for eMBB data It can be set separately.

11 is a block diagram illustrating a wireless communication system in which an embodiment of the present invention is implemented.

Referring to FIG. 11 , the terminal 1100 includes a memory 1105 , a processor 1110 , and an RF unit (radio frequency (RF) unit, 1115 ). The memory 1105 is connected to the processor 1110 and stores various information for driving the processor 1110 . The RF unit 1115 is connected to the processor 1110 to transmit and/or receive a radio signal. For example, the RF unit 1115 may receive an RRC message, configuration and/or control information such as DCI, and a downlink signal such as PDSCH and HARQ ACK/NACK posted herein from the base station 1150 . In addition, the RF unit 1115 may transmit an uplink signal such as PUSCH and HARQ ACK/NACK published in this specification to the base station 1150 .

The processor 1110 implements the functions, processes and/or methods of the terminal proposed in this specification. For example, the processor 1110 may configure a CBG according to an embodiment of the present invention and perform a retransmission operation according to HARQ. In all embodiments of the present specification, the operation of the terminal 1100 may be implemented by the processor 1110 .

The memory 1105 may store control information and setting information according to the present specification, and may provide the control information and setting information to the processor 1110 according to a request of the processor 1110 .

The base station 1150 includes a processor 1155 , a memory 1160 , and an RF unit (radio frequency (RF) unit, 1165 ). The memory 1160 is connected to the processor 1155 and stores various information for driving the processor 1155 . The RF unit 1165 is connected to the processor 1155 to transmit and/or receive a radio signal. The processor 1155 implements the functions, processes and/or methods of the base station proposed in this specification. In the above-described embodiment, the operation of the base station may be implemented by the processor 1155 . The processor 1155 may configure a downlink signal such as an RRC message, DCI, PDSCH, and HARQ ACK/NACK posted herein.

The processor may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits, and/or data processing devices. Memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and/or other storage devices. The RF unit may include a baseband circuit for processing a radio signal. When the embodiment of the present invention is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) that performs the above-described function. The module may be stored in a memory and executed by a processor. The memory may be internal or external to the processor, and may be coupled to the processor by various well-known means.

In the exemplary system described above, the methods are described on the basis of a flowchart as a series of steps or blocks, however, the present invention is not limited to the order of steps, and some steps may occur in a different order or concurrent with other steps as described above. can In addition, those skilled in the art will understand that the steps shown in the flowchart are not exhaustive and that other steps may be included or that one or more steps in the flowchart may be deleted without affecting the scope of the present invention.

Claims (10)

A method for a terminal to perform an HARQ operation in a wireless communication system, the method comprising:
First maximum value information of the number of code block groups per eMBB (enhanced Mobile Broad Band) transport block, and second maximum value information of the number of code block groups per URLLC (Ultra-Reliable and Low Latency Communication) transport block Receiving an RRC message comprising a from the base station; and
and performing a HARQ operation on uplink data in units of code blocks set based on any one of the first maximum value information and the second maximum value information. According to claim 1,
The method of claim 1, wherein the first maximum value information is one of a first maximum value set, and the second maximum value information is one of a second maximum value set. 3. The method of claim 2,
A plurality of maximum values included in the second maximum value set are relatively larger than a plurality of maximum values included in the first maximum value set. delete delete A method for a base station to perform an HARQ operation in a wireless communication system, the method comprising:
First maximum value information of the number of code block groups per eMBB (enhanced Mobile Broad Band) transport block, and second maximum value information of the number of code block groups per URLLC (Ultra-Reliable and Low Latency Communication) transport block Transmitting an RRC message comprising a to the terminal; and
and performing a HARQ operation on downlink data in units of code blocks set based on any one of the first maximum value information and the second maximum value information. 7. The method of claim 6,
The method of claim 1, wherein the first maximum value information is one of a first maximum value set, and the second maximum value information is one of a second maximum value set. 8. The method of claim 7,
A plurality of maximum values included in the second maximum value set are relatively larger than a plurality of maximum values included in the first maximum value set.
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