KR20220063725A - Method and apparatus for scheduling and hybrid automatic repeat request feedback in communication system - Google Patents

Abstract

Disclosed are a method and apparatus for scheduling and hybrid automatic repeat request (HARQ) feedback in a communication system. An operating method of a terminal includes the steps of: receiving downlink control information (DCI) from a base station; checking a plurality of start and length indicator values (SLIVs) indicated by a time domain resource allocation field included in the DCI; determining a plurality of physical downlink shared channel (PDSCH) resources based on the plurality of SLIVs; receiving a plurality of PDSCHs in the plurality of PDSCH resources from the base station; and transmitting a plurality of hybrid automatic repeat request-acknowledgements (HARQ-ACKs), which are responses to the plurality of PDSCHs, to the base station.

Description

METHOD AND APPARATUS FOR SCHEDULING AND HYBRID AUTOMATIC REPEAT REQUEST FEEDBACK IN COMMUNICATION SYSTEM

The present invention relates to a technique for scheduling and hybrid automatic repeat request (HARQ) feedback in a communication system, and more particularly, to a scheduling technique for a data channel and a HARQ feedback technique for a data channel.

For processing of rapidly increasing wireless data, a frequency band (eg, a frequency band of 6 GHz or more) higher than a frequency band (eg, a frequency band of 6 GHz or less) of long term evolution (LTE) (or LTE-A) A communication system (eg, a new radio (NR) communication system, a 6G communication system) using The NR communication system and/or the 6G communication system may support a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less, and may support various communication services and scenarios compared to the LTE communication system. For example, the usage scenario of the NR communication system and/or the 6G communication system may include enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), and massive Machine Type Communication (mMTC). . Communication technologies are needed to satisfy the requirements of eMBB, URLLC, and mMTC.

In particular, when separate downlink control information (DCI) is used for scheduling each of a plurality of PDSCHs in a transmission procedure of a plurality of physical downlink shared channels (PDSCHs), downlink signaling overhead may increase. In addition, when a plurality of hybrid automatic repeat requests (HARQ-ACKs) for a plurality of PDSCHs are transmitted through different physical uplink control channel (PUCCH) resources, uplink signaling overhead and transmission delay may increase.

An object of the present invention for solving the above problems is to provide a method and apparatus for scheduling a data channel and HARQ feedback for the data channel.

In order to achieve the above object, a method of operating a terminal according to a first embodiment of the present invention includes: receiving a DCI from a base station; checking a plurality of SLIVs indicated by a time domain resource allocation field included in the DCI; , determining a plurality of PDSCH resources based on the plurality of SLIVs, receiving a plurality of PDSCHs in the plurality of PDSCH resources from the base station, and a plurality of HARQ- in response to the plurality of PDSCHs and sending ACKs to the base station.

The plurality of HARQ-ACKs may be transmitted through one PUCCH resource, and the one PUCCH resource may be indicated by HARQ-ACK timing information included in the DCI.

The plurality of HARQ-ACKs may be included in one HARQ-ACK codebook, and the one HARQ-ACK codebook may be transmitted to the base station through one PUCCH resource.

The size of the one HARQ-ACK codebook may be determined based on a specific value instead of the number of the plurality of PDSCHs, and the specific value may be the maximum number of PDSCHs schedulable by one DCI.

The specific value may be B, the number of the plurality of PDSCHs may be C, B bits included in the one HARQ-ACK codebook may correspond to the one DCI, and among the B bits The plurality of HARQ-ACKs may be mapped to C bits, predefined values may be mapped to the remaining (B-C) bits among the B bits, B may be a natural number, and C is 0 or more B It may be an integer of the following.

The transmission time of the one HARQ-ACK codebook may be determined based on the reception time of the last PDSCH among the plurality of PDSCHs.

The number of the plurality of PDSCHs may be implicitly indicated by the number of the plurality of SLIVs.

The method of operating the terminal may further include receiving configuration information of a time resource list from the base station, wherein the time resource list may include a plurality of entries indicating a time resource, and the plurality of entries Each of the one or more entries may indicate two or more SLIVs, and the time domain resource allocation field may indicate one entry among the one or more entries.

The method of operating the terminal may further include transmitting information indicating the maximum number of schedulable PDSCHs in one slot to the base station.

The DCI can support both single PDSCH scheduling and multiple PDSCH scheduling, when the single PDSCH scheduling is performed, the DCI can schedule one PDSCH, and when the multiple PDSCH scheduling is performed, the DCI is the A plurality of PDSCHs can be scheduled.

The method of operating a base station according to a second embodiment of the present invention for achieving the above object includes the steps of transmitting a DCI to a terminal, based on a plurality of SLIVs indicated by a time domain resource allocation field included in the DCI. Transmitting a plurality of PDSCHs from the determined plurality of PDSCH resources to the terminal, and receiving a plurality of HARQ-ACKs in response to the plurality of PDSCHs from the terminal.

The plurality of HARQ-ACKs may be received through one PUCCH resource, and the one PUCCH resource may be indicated by HARQ-ACK timing information included in the DCI.

The plurality of HARQ-ACKs may be included in one HARQ-ACK codebook, and the one HARQ-ACK codebook may be received through one PUCCH resource.

The size of the one HARQ-ACK codebook may be determined based on a specific value instead of the number of the plurality of PDSCHs, and the specific value may be the maximum number of PDSCHs schedulable by one DCI.

The specific value may be B, the number of the plurality of PDSCHs may be C, B bits included in the one HARQ-ACK codebook may correspond to the one DCI, and among the B bits The plurality of HARQ-ACKs may be mapped to C bits, predefined values may be mapped to the remaining (B-C) bits among the B bits, B may be a natural number, and C is 0 or more B It may be an integer of the following.

The reception time of the one HARQ-ACK codebook may be determined based on the transmission time of the last PDSCH among the plurality of PDSCHs.

The number of the plurality of PDSCHs may be implicitly indicated by the number of the plurality of SLIVs.

The method of operating the base station may further include transmitting configuration information of a time resource list to the terminal, wherein the time resource list may include a plurality of entries indicating a time resource, and the plurality of entries Each of the one or more entries may indicate two or more SLIVs, and the time domain resource allocation field may indicate one entry among the one or more entries.

The method of operating the base station may further include receiving, from the terminal, information indicating the maximum number of schedulable PDSCHs in one slot.

The DCI can support both single PDSCH scheduling and multiple PDSCH scheduling, when the single PDSCH scheduling is performed, the DCI can schedule one PDSCH, and when the multiple PDSCH scheduling is performed, the DCI is the A plurality of PDSCHs can be scheduled.

According to the present application, the terminal may receive one downlink control information (DCI) for scheduling a plurality of physical downlink shared channels (PDSCH) from the base station, and may receive a plurality of PDSCHs from the base station according to one DCI. . Accordingly, downlink signaling overhead can be reduced. In addition, the UE may transmit one HARQ-ACK codebook composed of hybrid automatic repeat request-acknowledgements (HARQ-ACKs) for a plurality of PDSCHs to the base station using one physical uplink control channel (PUCCH) resource. . Accordingly, uplink signaling overhead and transmission delay can be reduced.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a conceptual diagram illustrating a first embodiment of a multi-PDSCH scheduling method.
4 is a conceptual diagram illustrating a first embodiment of a multi-PDSCH scheduling method in consideration of scheduling constraints.
5 is a conceptual diagram illustrating a first embodiment of a HARQ-ACK feedback method for multi-PDSCH scheduling.
6A is a conceptual diagram illustrating a second embodiment of a HARQ-ACK feedback method for multi-PDSCH scheduling.
6B is a conceptual diagram illustrating a third embodiment of a HARQ-ACK feedback method for multiple PDSCH scheduling.
7 is a conceptual diagram illustrating a first embodiment of a method for configuring a HARQ-ACK codebook for multi-PDSCH scheduling.
8 is a conceptual diagram illustrating a second embodiment of a method for configuring a HARQ-ACK codebook for multiple PDSCH scheduling.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. 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.

Terms such as first, second, etc. may be used to describe various elements, but the elements 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. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

In embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”. Also, in the embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said 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 in the present application are only used 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 application, 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 defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. 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 application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system may be a 4G communication system (eg, a long-term evolution (LTE) communication system, an LTE-A communication system), a 5G communication system (eg, a new radio (NR) communication system), and the like. The 4G communication system may support communication in a frequency band of 6 GHz or less, and the 5G communication system may support communication in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less. The communication system to which the embodiments according to the present invention are applied is not limited to the content described below, and the embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used in the same meaning as the communication network (network), and "LTE" may indicate "4G communication system", "LTE communication system" or "LTE-A communication system", and "NR" may indicate "5G communication system" or "NR communication system".

1 is a conceptual diagram illustrating a first embodiment of a communication system.

1, the communication system 100 is 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). In addition, the communication system 100 is a core network (core network) (eg, S-GW (serving-gateway), P-GW (packet data network (PDN)-gateway), MME (mobility management entity)) may include more. When the communication system 100 is a 5G communication system (eg, a new radio (NR) system), the core network is an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), etc. may include

The plurality of communication nodes 110 to 130 may support a communication protocol (eg, an LTE communication protocol, an LTE-A communication protocol, an NR communication protocol, etc.) defined in a 3rd generation partnership project (3GPP) standard. A plurality of communication nodes 110 to 130 are CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division) technology multiplexing) technology, Filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA Technology, Non-orthogonal Multiple Access (NOMA) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (Space Division Multiple Access) technology, etc. can support Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each of the components included in the communication node 200 may be connected by a bus 270 to communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1 , the communication system 100 includes a plurality of base stations 110 - 1 , 110 - 2 , 110 - 3 , 120 - 1 and 120 - 2 , and a plurality of terminals 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 cell 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 cell 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 to the cell coverage of the third base station 110-3. there is. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell 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 (NB), an evolved NodeB (eNB), gNB, an advanced base station (ABS), HR - BS (high reliability-base station), BTS (base transceiver station), radio base station (radio base station), radio transceiver (radio transceiver), access point (access point), access node (node), RAS (radio access station) ), MMR-BS (mobile multihop relay-base station), RS (relay station), ARS (advanced relay station), HR-RS (high reliability-relay station), HNB (home NodeB), HeNB (home eNodeB), It may be referred to as a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), and the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 includes a user equipment (UE), a terminal equipment (TE), an advanced mobile station (AMS), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable It may be referred to as a portable subscriber station, a node, a device, an on board unit (OBU), and the like.

Meanwhile, 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 link or a non-ideal backhaul link. , information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. 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 a 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

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between terminals (device to device communication, D2D) (or , Proximity Services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), and the like may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is the base station 110-1, 110-2, 110-3, and 120-1. , 120-2) and corresponding operations, and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. 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 is a terminal 130-1, 130-2, 130-3, 130-4 belonging to its own cell coverage. , 130-5, 130-6) and the CA method can transmit and receive signals. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 controls D2D between the fourth terminal 130-4 and the fifth terminal 130-5. and each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of the second base station 110-2 and the third base station 110-3, respectively. .

Methods for transmitting and receiving signals in a communication system will be described. In particular, a method for a base station to schedule a data channel to a terminal for downlink and uplink transmission in a communication system and a method for feeding back HARQ-ACK information for a corresponding data channel will be described. The following embodiments may be applied to not only the NR communication system but also other communication systems (eg, an LTE communication system, a fifth generation (5G) communication system, a sixth generation (6G) communication system, etc.).

The NR communication system may support a wider system bandwidth (eg, carrier bandwidth) than the system bandwidth provided by the LTE communication system in order to efficiently use a wide frequency band. For example, the maximum system bandwidth supported by the LTE communication system may be 20 MHz. On the other hand, the NR communication system may support a carrier bandwidth of up to 100 MHz in a frequency band of 6 GHz or less, and may support a carrier bandwidth of up to 400 MHz in a frequency band of 6 GHz or more.

Numerology applied to physical signals and channels in a communication system (eg, an NR communication system) may vary. Numerology can be varied to meet various technical requirements of a communication system. In a communication system to which a cyclic prefix (CP)-based OFDM waveform technology is applied, the numerology may include a subcarrier interval and a CP length (or CP type). Table 1 may be a first embodiment of a pneumatology configuration for a CP-OFDM based communication system. The subcarrier intervals may have a relationship of a power of two to each other, and the CP length may be scaled at the same rate as the OFDM symbol length. According to the frequency band in which the communication system operates, at least some of the pneumatologies of Table 1 may be supported. In addition, in the communication system, neurology(s) not listed in Table 1 may be further supported. For a specific subcarrier spacing (eg, 60 kHz), CP type(s) not listed in Table 1 (eg, extended CP) may be additionally supported.

In the following, a frame structure of a communication system will be described. Elements constituting a frame structure in the time domain may include a subframe, a slot, a mini-slot, a symbol, and the like. A subframe may be used in units of transmission, measurement, etc., and the length of the subframe may have a fixed value (eg, 1 ms) regardless of the subcarrier interval. A slot may include consecutive symbols (eg, 14 OFDM symbols). The length of the slot may be variable, different from the length of the subframe. For example, the length of the slot may be inversely proportional to the subcarrier spacing.

The slot may be used in units of transmission, measurement, scheduling, resource configuration, timing (eg, scheduling timing, hybrid automatic repeat request (HARQ) timing, channel state information (CSI) measurement and reporting timing, etc.). The length of the actual time resource used for transmission, measurement, scheduling, resource setting, etc. may or may not coincide with the length of the slot. A mini-slot may include consecutive symbol(s), and the length of the mini-slot may be shorter than the length of the slot. The mini-slot may be used in units of transmission, measurement, scheduling, resource configuration, timing, and the like. A mini-slot (eg, a mini-slot length, a mini-slot boundary, etc.) may be predefined in a technical specification. Alternatively, a mini-slot (eg, a mini-slot length, a mini-slot boundary, etc.) may be configured (or indicated) in the terminal. When a specific condition is satisfied, it may be configured (or instructed) in the terminal to use the mini-slot.

The base station may schedule a data channel (eg, a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), a physical sidelink shared channel (PSSCH)) using some or all of the symbols constituting the slot. . In particular, for URLLC transmission, unlicensed band transmission, transmission in a coexistence situation of an NR communication system and an LTE communication system, and multi-user scheduling based on analog beamforming, a data channel may be transmitted using a portion of a slot. Also, the base station may schedule the data channel using a plurality of slots. Also, the base station may schedule the data channel using at least one mini-slot.

Elements constituting the frame structure in the frequency domain may include a resource block (RB), subcarriers, and the like. One RB may include consecutive subcarriers (eg, 12 subcarriers). The number of subcarriers constituting one RB may be constant irrespective of the pneumatology. In this case, the bandwidth occupied by one RB may be proportional to the subcarrier spacing of the numerology. The RB may be used as a transmission and resource allocation unit such as a data channel and a control channel. Resource allocation of the data channel may be performed in units of RBs or RB groups (eg, resource block group (RBG)). One RBG may include one or more consecutive RBs. Resource allocation of the control channel may be performed in units of control channel elements (CCEs). In the frequency domain, one CCE may include one or more RBs.

In the NR communication system, a slot (eg, slot format) is at least one of a downlink (downlink, DL) section, a flexible section (or, an unknown section), and an uplink (uplink, UL) section It may be composed of a combination of sections. Each of the downlink section, the flexible section, and the uplink section may consist of one or more consecutive symbols. The flexible section may be located between the downlink section and the uplink section, between the first downlink section and the second downlink section, between the first uplink section and the second uplink section, and the like. When the flexible section is inserted between the downlink section and the uplink section, the flexible section can be used as a guard section.

A slot may include one or more flexible sections. Alternatively, the slot may not include a flexible section. The terminal may perform a predefined operation in the flexible section. Alternatively, the terminal may perform a semi-static or periodically set operation by the base station in the flexible section. For example, the operation periodically set by the base station is a PDCCH (physical downlink control channel) monitoring operation, SS/PBCH (synchronization signal/physical broadcast channel) block reception and measurement operation, CSI-RS (channel state information-reference signal) Reception and measurement operation, reception operation of downlink semi-persistent scheduling (SPS) PDSCH, sounding reference signal (SRS) transmission operation, physical random access channel (PRACH) transmission operation, PUCCH transmission operation configured periodically, configured grant ) may include a PUSCH transmission operation according to the The flexible symbol may be overridden by a downlink symbol or an uplink symbol. When the flexible symbol is overridden with a downlink or uplink symbol, the UE may perform a new operation instead of the existing operation on the corresponding flexible symbol (eg, an overridden flexible symbol).

The slot format may be semi-statically configured by higher layer signaling (eg, radio resource control (RRC) signaling). Information indicating the semi-static slot format may be included in system information, and the semi-static slot format may be cell-specifically configured. In addition, the semi-static slot format may be additionally configured for each UE through UE-specific higher layer signaling (eg, RRC signaling). A flexible symbol of a cell-specifically configured slot format may be overridden by a downlink symbol or an uplink symbol by UE-specific higher layer signaling. In addition, the slot format may be dynamically indicated by physical layer signaling (eg, a slot format indicator (SFI) included in downlink control information (DCI)). A semi-statically set slot format may be overridden by a dynamically indicated slot format. For example, a semi-statically configured flexible symbol may be overridden by a downlink symbol or an uplink symbol by SFI.

The terminal may perform a downlink operation, an uplink operation, a sidelink operation, and the like in a bandwidth part. The bandwidth portion may be defined as a set of contiguous RBs (eg, physical resource blocks (PRBs)) in a frequency domain having a specific numerology. One neurology may be used for signal transmission (eg, transmission of a control channel or a data channel) in one bandwidth portion. In embodiments, “signal” when used in a broad sense may mean any physical signal and channel. The terminal performing the initial access procedure may obtain configuration information of the initial bandwidth portion from the base station through system information. A terminal operating in an RRC connected state may obtain configuration information of a bandwidth portion from a base station through terminal-specific higher layer signaling.

The configuration information of the bandwidth part may include a numerology (eg, subcarrier spacing and/or CP length) applied to the bandwidth part. In addition, the configuration information of the bandwidth part further includes information indicating the location of the start RB (eg, start PRB) of the bandwidth part and information indicating the number of RBs (eg, PRB) constituting the bandwidth part can do. At least one bandwidth portion among the bandwidth portion(s) configured in the terminal may be activated. For example, each of one uplink bandwidth part and one downlink bandwidth part may be activated in one carrier. In a time division duplex (TDD)-based communication system, a pair of an uplink bandwidth portion and a downlink bandwidth portion may be activated. The base station may set a plurality of bandwidth portions in one carrier to the terminal, and may switch the active bandwidth portion of the terminal.

In the embodiments, "a frequency band (eg, carrier, bandwidth portion, RB set, listen before talk (LBT) subband, guard band, etc.) is activated" means "a base station or a terminal It may mean "a state in which a signal can be transmitted/received using a band (eg, an active frequency band)". In addition, "that the frequency band is activated" means "a radio frequency (RF) filter (eg, band pass filter) of the transmitter and receiver operates in a frequency band including the corresponding frequency band (eg, active frequency band) state".

In embodiments, RB may mean a common RB (CRB). Alternatively, RB may mean PRB or virtual RB (VRB). In the NR communication system, a CRB may mean an RB constituting a set (eg, a common RB grid) of RBs that are continuous based on a reference frequency (eg, point A). Carriers, bandwidth portions, etc. may be deployed on a common RB grid. That is, a carrier, a bandwidth portion, and the like may be composed of CRB(s). An RB or CRB constituting a bandwidth portion may be referred to as a PRB, and a CRB index within the bandwidth portion may be appropriately converted into a PRB index. In an embodiment, RB may mean an interlace RB (IRB). The IRB will be described later.

The PDCCH may be used to transmit DCI or DCI format to the UE. The minimum resource unit constituting the PDCCH may be a resource element group (REG). The REG may consist of one PRB (eg, 12 subcarriers) in the frequency domain and one OFDM symbol in the time domain. Accordingly, one REG may include 12 resource elements (REs). A demodulation reference signal (DM-RS) for decoding the PDCCH may be mapped to 3 REs among 12 REs constituting the REG, and control information (eg, modulated DCI) is transmitted to the remaining 9 REs. can be mapped to

One PDCCH candidate (candidate) may consist of one CCE or aggregated CCEs. One CCE may consist of a plurality of REGs. The NR communication system may support CCE aggregation levels 1, 2, 4, 8, 16, etc., and one CCE may consist of 6 REGs.

A control resource set (CORESET) may be a resource region in which the UE performs blind decoding of the PDCCH. CORESET may consist of a plurality of REGs. CORESET may consist of one or more PRBs in the frequency domain and one or more symbols (eg, OFDM symbols) in the time domain. Symbols constituting one CORESET may be continuous in the time domain. PRBs constituting one CORESET may be continuous or discontinuous in the frequency domain. One DCI (eg, one DCI format, one PDCCH) may be transmitted in one CORESET. A plurality of CORESETs may be configured from a cell viewpoint or a terminal viewpoint, and the plurality of CORESETs may overlap each other in time-frequency resources.

CORESET may be set in the UE by the PBCH (eg, system information transmitted through the PBCH). ID (identifier) of CORESET set by PBCH may be 0. That is, the CORESET set by the PBCH may be referred to as CORESET #0. The UE operating in the RRC idle state may perform a monitoring operation in CORESET #0 to receive the first PDCCH in the initial access procedure. Not only the UE operating in the RRC idle state but also the UE operating in the RRC connected state may perform a monitoring operation in CORESET #0. CORESET may be set in the terminal by other system information (eg, system information block type 1 (SIB1)) in addition to the system information transmitted through the PBCH. For example, in order to receive a random access response (or Msg2) in a random access procedure, the UE may receive SIB1 including configuration information of CORESET. In addition, CORESET may be set in the UE by UE-specific higher layer signaling (eg, RRC signaling).

One or more CORESETs for each downlink bandwidth portion may be configured for the UE. Here, "CORESET is set in the bandwidth part" may mean "CORESET is logically combined with the bandwidth part, and the terminal monitors the corresponding CORESET in the bandwidth part". The initial downlink active bandwidth part may include CORESET #0, and may be combined with CORESET #0. CORESET having a quasi co-location (QCL) relationship with an SS/PBCH block in a primary cell (PCell), a secondary cell (SCell), and/or a primary secondary cell (PSCell) #0 may be configured for the terminal. In the secondary cell, CORESET #0 may not be set for the UE.

A search space may be a set of candidate resource regions in which the PDCCH may be transmitted. The UE may perform blind decoding on each of the PDCCH candidates within a predefined search space. The UE may determine whether the PDCCH has been transmitted to the UE by performing a cyclic redundancy check (CRC) on the blind decoding result. When it is determined that the PDCCH is the PDCCH for the UE, the UE may receive the PDCCH.

The PDCCH candidate may be composed of CCE(s) selected by a predefined hash function within a CORESET or search space occurrence. The search space may be defined/configured for each CCE aggregation level. In this case, the sum of search spaces for all CCE aggregation levels may be referred to as a search space set. In embodiments, “search space” may mean “search space set”, and “search space set” may mean “search space”.

A search space set may be logically associated with one CORESET. One CORESET may be logically combined with one or more search space sets. A common search space set configured through the PBCH may be used to monitor DCI scheduling a PDSCH for transmitting SIB1. The ID of the common search space set configured through the PBCH may be set to 0. That is, the common search space set configured through the PBCH may be defined as a type 0 PDCCH common search space set or search space set #0. Search space set #0 can be logically combined with CORESET #0.

The search space set may be divided into a common search space set and a UE-specific search space set according to a purpose or a related operation. A common DCI may be transmitted in a common search space set, and a UE-specific DCI may be transmitted in a UE-specific search space set. Considering scheduling freedom and/or fallback transmission, UE-specific DCI may be transmitted even in a common search space set. For example, the common DCI may include resource allocation information of a PDSCH for transmission of system information, paging, a power control command, a slot format indicator (SFI), a preemption indicator, and the like. The UE-specific DCI may include resource allocation information of PDSCH, resource allocation information of PUSCH, and the like. A plurality of DCI formats may be defined according to a payload of DCI, a size, a type of a radio network temporary identifier (RNTI), and the like.

In embodiments, the common search space may be referred to as a common search space (CSS), and the common search space set may be referred to as a CSS set. Also, in embodiments, the UE-specific search space may be referred to as a UE-specific search space (USS), and the UE-specific search space set may be referred to as a USS set.

The base station may transmit a downlink transport block (TB) to the terminal through the PDSCH. The base station may transmit scheduling information of the PDSCH to the terminal, and the terminal may receive the PDSCH based on the scheduling information. The UE may receive downlink TB(s) included in the PDSCH. Downlink TB is unicast (unicast) data (eg, DL-SCH (downlink-shared channel)), broadcast (broadcast) data, multicast (multicast) data, or a higher layer control message (eg, RRC) message, a medium access control (MAC) control element (CE), a non-access stratum (NAS) message, etc.). For example, when the number of transport layers of the PDSCH exceeds a reference value (eg, a reference value: 4 in an NR communication system, a reference value: 1 in an LTE communication system), a plurality of PDSCHs (eg, two) of TBs. When the number of transport layers of the PDSCH is less than or equal to the reference value, the PDSCH may include one TB. In addition, the UE may receive DCI (eg, the second DCI of step 2 DCI) in the PDCCH resource region.

PDSCH scheduling may include scheduling by dynamic grant and semi-persistent scheduling (SPS) by configured grant. When PDSCH scheduling by dynamic grant is used, the PDSCH may be dynamically scheduled by DCI (eg, scheduling DCI, DCI formats 1_0, 1_1, 1_2, etc.). CRC applied to DCI for dynamic scheduling may be scrambled with C(cell)-RNTI, MCS-C-RNTI, or the like. When SPS is used, the UE may receive scheduling information of the PDSCH through RRC signaling and/or DCI, and may periodically receive the PDSCH based on the scheduling information. In addition, the PDSCH reception operation of the UE by the SPS may be activated or released by DCI. CRC applied to DCI for SPS may be scrambled with configured scheduling (CS)-RNTI, SPS-C-RNTI, or the like. The base station may transmit the PDSCH in every PDSCH resource. Alternatively, the base station may transmit the PDSCH in some PDSCH resources and may not transmit the PDSCH in some other PDSCH resources. The PDSCH by the SPS may be referred to as an SPS PDSCH.

In the embodiment below, it will be assumed that the number of transport layers of the PDSCH is less than or equal to the reference value (eg, when the PDSCH includes one TB), but the present application is not limited to the above-mentioned assumption and the PDSCH includes a plurality of TBs. In this case, the same or similar application may be applied. In addition, although PDSCH scheduling will be mainly described in the embodiment below, the present application may be equally or similarly applied to not only PDSCH scheduling but also scheduling of other data channels (eg, PUSCH, PSSCH). In addition, in the embodiment below, "TB" and "HARQ process" may be used interchangeably unless otherwise noted. For example, "PDSCH including TB" or "PDSCH corresponding to TB" may mean "PDSCH corresponding to HARQ process".

The UE may receive scheduling information of PDSCH(s) corresponding to one TB through one scheduling DCI. When PDSCH repetitive transmission is used, the above-described PDSCH(s) may be a plurality of PDSCHs. When the PDSCH repetition transmission is not used, the above-described PDSCH(s) may be one PDSCH. When SPS is used, PDSCH resource(s) corresponding to one TB may be allocated to the UE within one SPS period, and the UE may receive PDSCH(s) corresponding to one TB. According to the above method, in order for the base station to schedule a plurality of TBs (or a plurality of HARQ processes) to the terminal, a plurality of PDSCHs are scheduled through a plurality of DCIs or a plurality of PDSCHs are transmitted using a plurality of SPS settings. may have to

[Multiple PDSCH Scheduling Method]

The UE may perform a long-period PDCCH monitoring operation. For example, the UE may monitor the PDCCH in every X-th slot. As the value of X increases, the PDCCH monitoring complexity and power consumption of the UE may be reduced. X may be a natural number. The above-described method may be useful in a transmission operation in a high frequency band. In particular, the above-described method may be useful in a transmission operation in a slot having a short duration due to a large subcarrier interval (eg, 480 kHz, 960 kHz). In addition, long-period PDCCH monitoring can reduce DCI overhead. On the other hand, when X>1, according to the method of scheduling one TB through one DCI, the TB may be transmitted only in some slots, and downlink performance may be deteriorated according to this operation.

As a method for solving the above-described problem, the UE may receive scheduling information of a plurality of TBs through one scheduling DCI, and may receive a plurality of PDSCHs corresponding to the plurality of TBs. In the case of SPS, a plurality of PDSCH resources may be configured within one period through one SPS configuration, and the UE may receive a plurality of PDSCHs corresponding to a plurality of TBs from a plurality of PDSCH resources within one period. . The scheduling DCI may mean a downlink DCI, DCI formats 1_0, 1_1, 1_2, and the like. The method described above may be referred to as (Method 100). In (Method 100), each PDSCH or each TB may be transmitted in one slot. Alternatively, a certain PDSCH or a certain TB may be mapped to a plurality of slots and transmitted to the terminal.

3 is a conceptual diagram illustrating a first embodiment of a multi-PDSCH scheduling method.

Referring to FIG. 3 , the UE may monitor a PDCCH (eg, DCI) for downlink scheduling in every second slot. The UE may receive scheduling information of a plurality of TBs in a plurality of slots through one DCI by (method 100). The UE may obtain scheduling information for the first PDSCH of slot n and the second PDSCH of slot n+1 through DCI received in slot n, and may obtain scheduling information of slot n+2 through DCI received in slot n+2. Scheduling information for the third PDSCH and the fourth PDSCH of slot n+3 may be obtained. The first PDSCH and the second PDSCH may include different TBs, and the third PDSCH and the fourth PDSCH may include different TBs. According to an embodiment, the UE may receive a downlink TB in every slot even if PDCCH monitoring is omitted in some slots.

In (Method 100), when repeated PDSCH transmission is not applied, the number of TBs scheduled by one DCI and the number of PDSCHs may match, and TB(s) and PDSCH(s) may correspond one-to-one . When repeated PDSCH transmission is applied, the number of PDSCHs may be greater than the number of TBs scheduled by one DCI, and one TB may correspond to a plurality of PDSCHs.

The resource allocation information of the PDSCH may include time domain resource allocation information and frequency domain resource allocation information. The time domain resource allocation information of the PDSCH may include information about the start symbol of the PDSCH and the duration of the PDSCH (eg, the number of symbols constituting the PDSCH). Each of the start symbol and duration of the PDSCH may be expressed as an individual value. As another method, the start symbol and duration of the PDSCH may be expressed by being converted into one value (eg, start and length indicator value (SLIV)). In the following description, "start symbol and duration" and "SLIV" may be used interchangeably. The terminal can interpret "a symbol index of the start symbol of the PDSCH in the slot to which the PDSCH is mapped" or "a symbol offset of the start symbol of the PDSCH from one symbol (eg, the first symbol) of DCI scheduling the PDSCH". there is.

The time domain resource allocation information of the PDSCH may further include at least one of a slot offset, a PDSCH mapping type, or the number of repeated PDSCH transmissions (or the number of slots in which the PDSCH is aggregated) in addition to information about the start symbol and duration of the PDSCH. can The slot offset may mean an offset between a slot in which a scheduling DCI is transmitted and a slot in which a PDSCH is transmitted. The slot offset may be denoted by K0. The PDSCH mapping type may include type A and type B. In the case of PDSCH mapping type A, the DM-RS for demodulation of the PDSCH may be fixedly disposed in a specific symbol of the slot (eg, the 3rd or 4th symbol of the slot). A fixed symbol position may be configured in the UE through the PBCH. In the case of PDSCH mapping type B, the DM-RS for demodulation of the PDSCH may be arranged in one symbol (eg, the first symbol) among the symbol(s) to which the PDSCH is allocated. However, in some exceptional cases, the DM-RS for demodulation of the PDSCH may not be disposed in one of the symbol(s) to which the PDSCH is allocated.

In (Method 100), a plurality of PDSCHs may have the same start symbol and duration. In this case, the same SLIV may be applied to a plurality of PDSCHs. A plurality of PDSCHs may be allocated to different slots. The UE may acquire information of one SLIV through DCI.

Alternatively, it may be allowed for a plurality of PDSCHs to have different start symbols and durations. That is, different SLIVs may be applied to a plurality of PDSCHs. In this case, a plurality of PDSCHs may be allocated to different slots or may be allocated to the same slot. The UE may obtain information (eg, an indication) on a plurality of SLIVs through DCI. Each SLIV may correspond to one PDSCH. For example, SLIV(s) and PDSCH(s) may have a one-to-one correspondence regardless of whether or not the PDSCH is repeatedly transmitted. The UE may regard the number of SLIVs as the number of scheduled PDSCHs. Alternatively, each SLIV may correspond to one TB. In this case, one SLIV may correspond to one PDSCH or a plurality of PDSCHs depending on whether the PDSCH is repeatedly transmitted.

The UE may receive information on whether the above-described multiple PDSCH scheduling method is applied through a signaling procedure (eg, RRC signaling procedure, specific RRC message, MAC CE, DCI) from the base station.

The time domain resource allocation information of the PDSCH may be transmitted to the UE through higher layer signaling (eg, RRC signaling) and/or DCI. Candidate(s) for time domain resource allocation of PDSCH may be configured in the UE through higher layer signaling (eg, RRC signaling). In the following embodiment, a candidate may mean a time domain resource allocation candidate. When there is one candidate (ie, time domain resource allocation candidate), one piece of time domain resource allocation information may be applied to scheduling, and the scheduling DCI may not include information indicating time domain resource allocation information. On the other hand, when there are a plurality of candidates, one (or at least one) of the candidates may be applied to scheduling. The base station may select one (or at least one) of the candidates, and may perform a time domain resource allocation operation of the PDSCH based on the selected candidate(s). The UE may receive information on the selected candidate(s) through DCI, and may perform a PDSCH reception operation based on the selected candidate(s).

Table 2 may show a first embodiment of parameters for time domain resource allocation of PDSCH. Each row or each entry in Table 2 may represent one time domain resource allocation candidate, and each column is in time domain resource allocation information (eg, time domain resource allocation candidate). It may indicate which information element is included. The parameters of Table 2 may be configured through higher layer signaling (eg, RRC signaling). For example, the base station may transmit the configuration information of Table 2 to the terminal through RRC signaling, and the terminal may receive the configuration information of Table 2 from the base station. In an embodiment, a table (eg, Table 2) set by RRC signaling may be referred to as an RRC table, a time resource table, or a time resource list.

The time domain resource allocation candidate corresponding to each entry in the RRC table is at least one information among slot offset(s), PDSCH mapping type(s), SLIV(s), or the number of repeated transmissions (or the number of aggregated slots). may include The base station may select one (or at least one) entry from among the entry(s) constituting the RRC table, and time domain resource allocation information corresponding to the selected entry(s) (eg, the selected entry(s)) )) may be indicated to the UE through DCI.

When the multiple PDSCH scheduling method is used, an entry constituting the RRC table set in the UE may include a plurality of SLIVs. Referring to Table 2, entry number 1 including two SLIVs and entry number 2 including three SLIVs may be configured in the terminal. When entry 1 or 2 is indicated through DCI, the UE may determine the positions of PDSCH resources based on two or three SLIVs, and may perform a PDSCH reception operation at the determined positions. According to an embodiment, a plurality of entries constituting the same RRC table may include different numbers of SLIV(s). A plurality of entries constituting the same RRC table may include scheduling information of different numbers of TBs or different numbers of PDSCHs. The UE may determine the number of TB(s) to be received and/or the number of PDSCH(s) based on the number of scheduled SLIV(s). The base station may dynamically change the number of TB(s) and/or the number of PDSCH(s) scheduled to the terminal by selectively applying a plurality of entries to PDSCH scheduling.

When a single PDSCH scheduling method is used, an entry constituting the RRC table set in the UE may include one SLIV. Referring to Table 2, entry 0 including one SLIV may be set in the terminal. According to an embodiment, some entries among a plurality of entries constituting the same RRC table may include a plurality of SLIVs, and some other entries may include one SLIV. Among a plurality of entries constituting the same RRC table, some entries may include scheduling information for a plurality of TBs or a plurality of PDSCHs, and some other entries include scheduling information for one TB or one PDSCH. can do. The base station can dynamically select or switch between a single PDSCH scheduling method and a multiple PDSCH scheduling method by selectively applying a plurality of entries to PDSCH scheduling. In an embodiment, a single PDSCH scheduling method may mean a scheduling method to which multiple PDSCH scheduling is not applied. When a single PDSCH scheduling method is used, one DCI may schedule one TB. According to the single PDSCH scheduling method, one DCI may indicate one SLIV.

Referring to Table 2, an entry including a plurality of SLIVs in the RRC table may include one slot offset. One slot offset may be applied to the first scheduled PDSCH (eg, PDSCH corresponding to the first SLIV). An entry including a plurality of SLIVs may include one PDSCH mapping type. One PDSCH mapping type may be applied to all scheduled PDSCHs. According to another embodiment, an entry including a plurality of SLIVs in the RRC table may include a plurality of slot offsets and/or a plurality of PDSCH mapping types. The number of SLIVs included in each entry and the number of slot offset information may be the same, and each slot offset may be used to determine a slot of a PDSCH (or TB) corresponding to each SLIV. The number of SLIVs included in each entry and the number of PDSCH mapping type information may be the same, and each PDSCH mapping type may be applied to a PDSCH (or TB) corresponding to each SLIV. According to the method, scheduling flexibility can be increased. The method may be particularly useful in a time division duplex (TDD) system in which a downlink section and an uplink section are intersected.

In an embodiment, the maximum value of the number of SLIVs that can be set or indicated to the terminal through one DCI (or for SPS PDSCH transmission within one period) (or the maximum value of the number of TBs, the maximum value of the number of PDSCHs, etc.) may be set in the terminal or defined in a technical standard. For example, information on the maximum value of the number of SLIVs may be transmitted to the terminal together with information for configuring that the multi-PDSCH scheduling method is to be applied to the terminal. The number of SLIVs (or the number of TBs, the number of PDSCHs) included in each entry of the RRC table may not exceed a preset maximum value.

Meanwhile, the size and/or interpretation criteria of a field value of a DCI for scheduling a PDSCH may be determined by the number of SLIVs, the number of TBs, and/or the number of PDSCHs scheduled by the corresponding DCI. For example, each of the number of RVs indicated by the redundancy version (RV) field and the number of NDIs indicated by the new data indicator (NDI) field is the same as the number of SLIVs or the number of TBs scheduled by the same DCI. can Alternatively, each of the number of RVs indicated by the RV field and the number of NDIs indicated by the NDI field may be determined by the number of SLIVs or the number of TBs scheduled by the same DCI. For another example, when the scheduling DCI indicates a plurality of SLIVs or schedules a plurality of TBs, a code block group transmission indicator (CBGTI) field may not exist in the corresponding scheduling DCI. Here, the size of the CBGTI field may be 0. When the scheduling DCI indicates one SLIV or schedules one TB, the CBGTI field may exist in the corresponding scheduling DCI. Here, the size of the CBGTI field may be 1 bit or more. The UE may interpret the CBGTI field based on the method, and may find out which CBG(s) the received PDSCH includes according to the analysis result.

The UE may check at least one of the number of scheduled SLIVs, the number of TBs, and the number of PDSCHs by first interpreting the time domain resource allocation field of DCI. The UE may interpret the above-described fields (eg, RV, NDI, CBGTI, etc.) based on the analysis result of the time domain resource allocation field. In this case, the time domain resource allocation field of the DCI may have a fixed size and location within the payload of the DCI regardless of the number of scheduled SLIVs, the number of TBs, and/or the number of PDSCHs. As a method for supporting this operation, the time domain resource allocation field of DCI is in the bit(s) (eg, most significant bit (MSB)) preceding the above fields (eg, RV, NDI, CBGTI, etc.) may be mapped to the nearest bit(s)).

Alternatively, the criteria for interpretation of the field size and/or field value of DCI are "whether multiple PDSCH scheduling method is applied (or configured)" and/or "the maximum value of the number of SLIVs set in the terminal (or the number of TBs) maximum value, the maximum value of the number of PDSCHs)". Alternatively, the interpretation criteria of the field size and/or field value of DCI are the SLIV number(s), TB number(s), or It may be determined based on the largest value among the PDSCH number(s).

For single PDSCH scheduling and multiple PDSCH scheduling, one DCI format (eg, DCI formats 1_0, 1_1, 1_2, etc.) may be commonly used. A commonly used DCI format may be referred to as a “common DCI format”. At this time, the size of the DCI payload (hereinafter referred to as "first payload") used for multiple PDSCH scheduling is the DCI payload used for single PDSCH scheduling (hereinafter referred to as "second payload"). may be different from the size of In this case, the size of the payload of the common DCI format may follow the larger of the size of the first payload and the size of the second payload. DCI payload may include fields of DCI. Zero padding may be applied to a DCI payload having a smaller size among DCI payloads (eg, the first payload and the second payload), and the size of the DCI payload may be larger among the DCI payloads. It may be sorted based on the size of the DCI payload. According to the method, the UE may monitor a single DCI format (eg, a common DCI format) having a single size in order to receive multiple PDSCH scheduling information and single PDSCH scheduling information. A single DCI format may be transmitted/received using a common RNTI (eg, C-RNTI, MCS-C-RNTI, CS-RNTI, etc.).

Alternatively, the DCI format used for multiple PDSCH scheduling (hereinafter, referred to as “first DCI format”) may be different from the DCI format used for single PDSCH scheduling (hereinafter referred to as “second DCI format”). . In general, the payload size of the first DCI format and the payload size of the second DCI format may be different from each other. In this case, the PDCCH blind decoding complexity of the UE may increase. In order to solve this problem, a procedure of aligning the payload size of the first DCI format and the payload size of the second DCI format may be performed. For example, by applying zero padding to a DCI format having a small payload among DCI formats, payload sizes of the corresponding DCI formats may be aligned. In this case, in order to distinguish the first DCI format from the second DCI format, the base station and the terminal may scramble the CRC of the first DCI format and the CRC of the second DCI format using different RNTIs. Alternatively, in order to distinguish the first DCI format from the second DCI format, an indicator or field for distinguishing the DCI format (eg, an indicator or field indicating that the first DCI format or the second DCI format) is the first It may be included in 1 DCI format and 2nd DCI format. The indicator or field may be mapped to bit(s) at the same position in the DCI payload received by the UE regardless of the DCI format.

The UE may receive one or a plurality of PDSCHs (eg, one or a plurality of unicast PDSCHs) in one slot. A plurality of PDSCHs may not overlap each other in the time domain. Alternatively, the UE may receive a maximum of one PDSCH (eg, a maximum of one unicast PDSCH) in one slot. The maximum number of PDSCHs (eg, unicast PDSCHs) that the terminal can receive in one slot may be defined as the capability of the terminal, and the terminal may report the corresponding capability to the base station. That is, the capability of the terminal may include information indicating the maximum number of PDSCHs that can be received in one slot. Capability (eg, the maximum number of PDSCHs that can be received in one slot) may be different for each numerology (eg, subcarrier spacing) or frequency band, and the terminal may have a numerology (eg, subcarrier spacing) However, the capability may be reported to the base station for each frequency band. For example, the maximum number of receivable PDSCHs per slot may be small when a short slot duration is used (eg, when a large subcarrier spacing is used) or in a high frequency band. In the embodiment, "unicast PDSCH", "PDSCH scheduled specifically for terminal", "PDSCH including TB(s)", "PDSCH including DL-SCH", and "C-RNTI, MCS-C- "PDSCH scheduled by DCI having a CRC scrambled by at least one of RNTI or CS-RNTI" may be used in common with each other.

In (Method 100), a maximum of one PDSCH may be scheduled in one slot. A plurality of PDSCHs may be allocated to consecutive slots. For example, a first slot to which the first PDSCH is allocated may be indicated or configured by the UE, and PDSCHs after the first PDSCH may be allocated to consecutive slots after the first slot. Alternatively, a plurality of PDSCHs may be assigned to contiguous or non-contiguous slots. For example, a slot to which each PDSCH is allocated may be indicated or configured to the UE. For another example, a slot to which the first PDSCH is allocated may be indicated or configured by the terminal, and a slot distance (eg, a slot offset) between slots to which the PDSCHs are allocated may be indicated or configured by the terminal. This operation may be referred to as (method 110). In (Method 110), each SLIV may be used to determine the symbol(s) to which the PDSCH is mapped in each slot.

Alternatively, it may be allowed to allocate a plurality of PDSCHs to one slot. The total number of slots in which PDSCHs are scheduled may be one or more. This operation may be referred to as (method 120). In (Method 120), each SLIV may be used to determine the symbol(s) to which each PDSCH is mapped. Alternatively, each SLIV may be used to determine symbol(s) to which a specific PDSCH (eg, the first PDSCH in each slot) is mapped in each slot. When a plurality of PDSCHs are allocated to one slot, the symbol(s) to which the remaining PDSCH(s) other than a specific PDSCH (eg, the first PDSCH) are mapped is at the position of the time resource of the previous PDSCH(s) in the same slot. can be determined based on For example, a plurality of PDSCHs scheduled in one slot may be consecutive in the time domain, and the start symbol of the following PDSCH(s) may be determined as the next symbol of the last symbol of the immediately preceding PDSCH. A plurality of PDSCHs scheduled in one slot may have the same duration (ie, the number of symbols). The base station may determine whether to apply (method 110) or (method 120) to the terminal based on the capability received from the terminal. The base station may transmit information indicating application of (method 110) or (method 120) to the terminal. The terminal may apply (Method 110) or (Method 120) according to the instruction of the base station.

4 is a conceptual diagram illustrating a first embodiment of a multi-PDSCH scheduling method in consideration of scheduling constraints.

Referring to FIG. 4 , the UE may obtain scheduling information for the first to fourth PDSCHs in slots n to n+3 through the first DCI (eg, first PDCCH) received in slot n. there is. A plurality of PDSCHs may be allocated to consecutive slots. A plurality of PDSCHs may include a plurality of different TBs. Symbol(s) to which each PDSCH is mapped in a slot may be indicated by each SLIV of the first DCI.

The UE may acquire scheduling information of the PDSCH(s) through a DCI different from the first DCI (eg, a second DCI). In this case, the PDSCH(s) scheduled by the second DCI is allocated to a section preceding the start PDSCH (eg, the start symbol of the first PDSCH) scheduled by the first DCI, or scheduled by the first DCI It may be allocated to a later period than the last PDSCH (eg, the end symbol of the fourth PDSCH). PDSCH(s) scheduled by the second DCI may not be allocated in sections other than the aforementioned sections. For example, PDSCH(s) scheduled by the second DCI may not be allocated to an interval between PDSCHs scheduled by the first DCI. In this case, the second DCI may be a DCI transmitted later than the first DCI. Specifically, the above-described method is "when the end symbol of the first DCI precedes the end symbol of the second DCI", "when the start symbol of the first DCI precedes the start symbol of the second DCI", or "the first DCI It can be applied to "the case where the end symbol of ' is ahead of the start symbol of the second DCI. The above-described method may be applied to general PDSCH scheduling.

According to the embodiment, the UE may not expect to acquire the scheduling information of the fifth PDSCH located between the first PDSCH and the second PDSCH through the second DCI in slot n+1. If the second DCI scheduling the 5th PDSCH is received, the UE may consider that the PDSCH scheduling indication by the second DCI is incorrect, and may not receive the 5th PDSCH scheduled by the second DCI. In addition, the UE may consider that other instructions (eg, CSI request, SRS request, etc.) other than the PDSCH scheduling instruction included in the second DCI are also incorrect, and may not follow the instruction. Alternatively, the UE may consider other indications (eg, CSI request, SRS request, etc.) other than the PDSCH scheduling indication included in the second DCI as valid, and may perform an operation according to the indication. When the second DCI is received, the UE may not receive the fifth PDSCH and at the same time not receive some of the PDSCHs scheduled by the first DCI. For example, the UE may not receive PDSCHs allocated after the fifth PDSCH among PDSCHs scheduled by the first DCI.

In the above-described embodiment, the UE may receive the scheduling indication of the 6th PDSCH located between the 3rd PDSCH and the 4th PDSCH in slot n+2. The sixth PDSCH may be a PDSCH by SPS. In addition, the UE may receive a scheduling indication of the 7th PDSCH after the 4th PDSCH in slot n+3. According to the above-described method, the scheduling indication for the 7th PDSCH may be considered valid, and the UE may perform a reception operation for the 7th PDSCH according to the scheduling indication. Here, the scheduling indication of the 6th PDSCH may be considered invalid.

In the embodiment described above, the PDSCHs may be unicast PDSCHs. The above-described method may be applied to a terminal to which scheduling of at most one PDSCH (eg, at most one unicast PDSCH) may be indicated or configured in one slot. Alternatively, the above-described method may be applied to a terminal to which scheduling of a plurality of PDSCHs (eg, a plurality of unicast PDSCHs) can be indicated or configured in one slot.

[HARQ Feedback Method]

HARQ may be applied to PDSCH transmission. The UE may feed back HARQ-ACK (acknowledgement) information, which is a result of receiving the scheduled PDSCH, to the base station, and the base station may determine whether to retransmit the PDSCH for the corresponding TB based on the HARQ-ACK information. When the UE successfully receives the PDSCH (eg, TB), HARQ-ACK information corresponding to the TB may be ACK. When the UE does not successfully receive the PDSCH (eg, the corresponding TB), HARQ-ACK information corresponding to the corresponding TB may be NACK. In addition, a certain PDSCH (eg, a corresponding TB) scheduled for the terminal may not be transmitted when a predetermined condition is satisfied (eg, transmission may be omitted). In this case, HARQ-ACK information corresponding to the TB may be NACK. The certain PDSCH (eg, corresponding TB) may be one PDSCH (eg, one TB) of a plurality of PDSCHs (eg, a plurality of TBs) scheduled by a single DCI. For example, the certain PDSCH (eg, the corresponding TB) may overlap an uplink symbol, and the base station may omit transmission of the certain PDSCH (eg, the corresponding TB). The HARQ-ACK information may include only ACK or only NACK. Alternatively, the HARQ-ACK information may include ACK or NACK. In an embodiment, HARQ-ACK information, HARQ-ACK bit, HARQ-ACK response, HARQ-ACK feedback, and HARQ-ACK may be used with the same meaning. The size of HARQ-ACK information corresponding to each downlink TB may be 1 bit. A CBG-based HARQ transmission scheme may be used, and one TB may consist of N CBG(s). N may be a natural number. In this case, N-bit HARQ-ACK information may correspond to each downlink TB. In the embodiment below, unless otherwise stated, it may be assumed that HARQ-ACK feedback in units of TB is performed, and that HARQ-ACK information of 1 bit corresponds to one downlink TB.

The UE may receive an indication or configuration of an uplink resource (eg, PUCCH resource, PUSCH resource, SRS resource, etc.) for transmitting HARQ-ACK (eg, HARQ-ACK information) from the base station. The UE may receive an indication or configuration of a time distance from the reception time of the PDSCH to the transmission time of the HARQ-ACK for the corresponding PDSCH (hereinafter referred to as "HARQ-ACK timing") from the base station, and at the HARQ-ACK timing Based on the HARQ-ACK feedback time may be determined. Information on HARQ-ACK timing may be included in DCI or SPS configuration information for scheduling PDSCH. Each of the PDSCH reception time point and the HARQ-ACK feedback time point may mean a slot, a subslot, a minislot, or a symbol including the corresponding time point. The HARQ-ACK timing may mean a slot offset, a subslot offset, a minislot offset, or a symbol offset between a PDSCH reception time and a HARQ-ACK feedback time. Slots, subslots, minislots, and symbols may be slots, subslots, minislots, and symbols of a portion of the uplink bandwidth. Alternatively, the slots, subslots, minislots, and symbols may be slots, subslots, minislots, and symbols of a downlink bandwidth portion. The HARQ-ACK timing may be denoted by K1.

A subslot may mean a time unit shorter than a slot, and may be used as a unit for a transmission/reception operation, a measurement operation, and/or a timing determination operation. The number of symbols constituting the subslot may be one of divisor(s) of the number of symbols constituting the slot. For example, when one slot includes 14 symbols, the number of symbols included in one subslot may be 1, 2, 4, or 7. The subslots may be placed consecutively in the time domain. In the embodiment below, a case in which the PDSCH scheduling operation and the HARQ feedback operation is performed in units of slots will be mainly described. . By interpreting "slot" as "subslot" in the embodiment, the operation in units of subslots can be understood.

The UE may generate a HARQ-ACK codebook including HARQ-ACK information of the PDSCH, and may report the HARQ-ACK codebook to the base station. The PDSCH may be a PDSCH by a dynamic grant or an SPS PDSCH. The HARQ-ACK codebook may include HARQ-ACK for DCI indicating release of the SPS PDSCH. The type of the HARQ-ACK codebook is a HARQ-ACK codebook having a semi-static size (hereinafter, referred to as “Type 1 HARQ-ACK codebook”), a HARQ-ACK codebook having a dynamic size (hereinafter referred to as “Type 2 HARQ-ACK”). Codebook"), and a HARQ-ACK codebook for feeding back HARQ-ACK(s) for multiple (eg, all) downlink HARQ process(s) at once (hereinafter, "Type 3 HARQ-ACK codebook") ") may be included. Each downlink HARQ-ACK may be mapped to each bit constituting the payload of the HARQ-ACK codebook. The size of the HARQ-ACK codebook may be 1 or more. The HARQ-ACK codebook may be transmitted to the base station through an uplink signal or a channel (eg, PUCCH, PUSCH, SRS, etc.).

In the case of multiple PDSCH scheduling, the UE may obtain scheduling information of a plurality of downlink TBs through one DCI, and may report a plurality of HARQ-ACKs corresponding to the plurality of downlink TBs to the base station. In the case of SPS, a plurality of downlink TBs may be transmitted within one SPS configuration and one SPS period, and the terminal may report a plurality of HARQ-ACKs corresponding to the plurality of downlink TBs to the base station. In this case, a plurality of HARQ-ACKs corresponding to the plurality of TBs may be included in the same HARQ-ACK codebook, and the UE may report the same HARQ-ACK codebook to the base station. A plurality of HARQ-ACKs may be transmitted to the base station at the same time point and may be transmitted to the base station through the same uplink resource (eg, PUCCH, PUSCH, SRS, etc.). The HARQ-ACK timing is defined as the distance between the transmission time of any one of the plurality of PDSCHs corresponding to the plurality of TBs (eg, the last transmitted PDSCH, the PDSCH corresponding to the last TB) and the HARQ-ACK feedback time. can be The method described above may be referred to as (method 200).

5 is a conceptual diagram illustrating a first embodiment of a HARQ-ACK feedback method for multi-PDSCH scheduling.

Referring to FIG. 5 , the UE may receive DCI in slot n, and the DCI may include scheduling information of a first PDSCH in slot n and scheduling information of a second PDSCH in slot n+1. The slot offset K0 for the first PDSCH may be 0, and the slot offset K0 for the second PDSCH may be 1. The first PDSCH may include a first TB, and the second PDSCH may include a second TB. The first TB and the second TB may be different from each other.

According to (Method 200), the HARQ-ACK for the first TB and the HARQ-ACK for the second TB may be included in the same HARQ-ACK codebook, and uplink at the same time point (eg, slot n+2). It may be transmitted to the base station through a resource (eg, PUCCH). For this operation, the UE may acquire “HARQ-ACK timing (K1)=1” through DCI. The UE may interpret it as “a slot distance between a reception slot of the last PDSCH (eg, a second PDSCH) among a plurality of PDSCHs and a transmission slot of the HARQ-ACK codebook is 1” based on “K1=1”. .

According to (Method 200), the UE may perform one HARQ-ACK feedback operation for a plurality of scheduled TBs, and may receive one HARQ-ACK timing for one HARQ-ACK feedback operation from the base station. there is. Accordingly, an uplink signaling overhead resource for HARQ-ACK feedback and a downlink signaling overhead for HARQ-ACK timing indication can be reduced. When the transmission time of HARQ-ACKs is determined based on the reception time of the latest TB, the delay time of downlink transmission may increase.

As a method for solving the above-mentioned problem, each of a plurality of HARQ-ACKs corresponding to a plurality of TBs may be included in different HARQ-ACK codebooks, and the terminal reports different HARQ-ACK codebooks to the base station. can For example, the first HARQ-ACK corresponding to the first TB may be included in the first HARQ-ACK codebook, and the second HARQ-ACK corresponding to the second TB may be included in the second HARQ-ACK codebook. The first HARQ-ACK codebook may be the same as the second HARQ-ACK codebook. Alternatively, the first HARQ-ACK codebook may be different from the second HARQ-ACK codebook. Each of the plurality of HARQ-ACKs may be transmitted to the base station at different time points, and may be transmitted to the base station through different uplink resources (eg, PUCCH, PUSCH, SRS, etc.). For example, the first HARQ-ACK codebook may be transmitted through the first uplink resource at the first time point, and the second HARQ-ACK codebook may be transmitted through the second uplink resource at the second time point. The first time point may be the same as the second time point. Alternatively, the first time point may be different from the second time point. The first uplink resource may be the same as the second uplink resource. Alternatively, the first uplink resource may be different from the second uplink resource. The method described above may be referred to as (Method 210).

6A is a conceptual diagram illustrating a second embodiment of a HARQ-ACK feedback method for multi-PDSCH scheduling, and FIG. 6B is a conceptual diagram illustrating a third embodiment of a HARQ-ACK feedback method for multi-PDSCH scheduling.

6A and 6B, the UE may receive DCI in slot n, and through the DCI, scheduling information of a first PDSCH in slot n and scheduling information of a second PDSCH in slot n+1 may be obtained. there is. The slot offset for the first PDSCH may be 0, and the slot offset for the second PDSCH may be 1. The first PDSCH may include a first TB, and the second PDSCH may include a second TB. The first TB and the second TB may be different from each other.

Embodiments may be practiced by (method 210). Referring to FIG. 6A , HARQ-ACKs for a first TB and a second TB may be included in different HARQ-ACK codebooks, and different HARQ-ACK codebooks may be reported to the base station at different time points. For example, the HARQ-ACK for the first TB may be transmitted to the base station in slot n+1, and the HARQ-ACK for the second TB may be transmitted to the base station in slot n+2. Referring to FIG. 6B , HARQ-ACKs for a first TB and a second TB may be included in the same HARQ-ACK codebook, and the same HARQ-ACK codebook may be reported to the base station at the same time. For example, both HARQ-ACKs for the first TB and the second TB may be transmitted to the base station in slot n+2.

In the above-described embodiment, the terminal may receive an indication or configuration of one HARQ-ACK timing from the base station. One HARQ-ACK timing may be equally applied to each of a plurality of TBs (or a plurality of PDSCHs) scheduled by DCI, and the HARQ-ACK feedback time derived by one HARQ-ACK timing is TB ( For example, it may be different for each PDSCH). Referring to FIG. 6A , the UE may receive HARQ-ACK timing information (eg, K1=1) commonly applied to the first TB and the second TB from the base station, and based on the HARQ-ACK timing HARQ-ACK feedback timings of the first TB and the second TB may be determined.

Alternatively, the terminal may receive an indication or configuration of a plurality of HARQ-ACK timings from the base station. Each of the plurality of HARQ-ACK timings may be applied to each TB (eg, each PDSCH) scheduled by DCI, and TBs derived by the plurality of HARQ-ACK timings (eg, PDSCHs) HARQ-ACK feedback timings may be the same or different from each other. Referring to FIG. 6B , the UE may receive HARQ-ACK timing information for the first TB (K1=2) and HARQ-ACK timing information for the second TB (K1=1) from the base station, and HARQ - HARQ-ACK feedback timings of the first TB and the second TB may be determined based on the ACK timing. Referring to FIG. 6A , the UE may receive HARQ-ACK timing information for the first TB (K1=1) and HARQ-ACK timing information for the second TB (K1=1) from the base station, and HARQ - HARQ-ACK feedback timings of the first TB and the second TB may be determined based on the ACK timing. At this time, if the HARQ-ACK feedback time points for the plurality of TBs (eg, the first TB and the second TB) are the same, the HARQ-ACKs for the plurality of TBs may be included in the same HARQ-ACK codebook. .

In (Method 210), the UE may receive an indication or configuration of a plurality of uplink resources (eg, PUCCH, PUSCH, SRS, etc.) for transmitting a plurality of HARQ-ACKs. For example, the UE receives an indication or configuration of a first PUCCH resource for transmitting the HARQ-ACK of the first TB and a second PUCCH resource for transmitting the HARQ-ACK of the second TB through DCI for scheduling the PDSCH. can do. The transmission time of the first PUCCH and the second PUCCH may follow the HARQ-ACK feedback time determined by the above-described method. When the transmission time (eg, slot, subslot) of the first PUCCH and the second PUCCH are the same, HARQ-ACKs for the first TB and the second TB may be included in the same HARQ-ACK codebook, and the same HARQ- The ACK codebook may be transmitted through one uplink resource. One uplink resource may be the first PUCCH or the second PUCCH. Alternatively, one uplink resource may be a signal or channel other than the first PUCCH and the second PUCCH (eg, PUSCH, SRS, third PUCCH, etc.).

The above-described information on HARQ-ACK timing(s) and information on PUCCH resource(s) may be included in DCI for scheduling corresponding TBs, and the DCI may be transmitted to the UE. Alternatively, the information on the above-described HARQ-ACK timing(s) and information on the PUCCH resource(s) may be semi-statically configured in the terminal through higher layer signaling (eg, RRC signaling, SPS configuration message). .

[Type 2 HARQ-ACK Codebook]

When the type 2 HARQ-ACK codebook is used, the UE may map HARQ-ACK(s) for TB(s) scheduled through DCI to bit(s) in the HARQ-ACK codebook. When the multiple PDSCH scheduling method is used, one DCI may correspond to one or more bit(s) in the HARQ-ACK codebook. When HARQ-ACKs corresponding to a plurality of DCIs are included in one HARQ-ACK codebook, the order in which HARQ-ACKs corresponding to the plurality of DCIs are mapped to the payload of the HARQ-ACK codebook is the PDCCH in which the DCIs are transmitted. It may be determined according to a time resource (eg, a start symbol) and/or a serving cell of monitoring occasions (or CORESETs, search space sets). For example, indexing for PDCCH monitoring occasions having the same start symbol among PDCCH monitoring occasions corresponding to the same HARQ-ACK codebook is performed by the cell ID of the serving cell (eg, physical layer cell ID, upper layer configuration). ID) may be performed in ascending order (or descending order), and then indexing for the corresponding PDCCH monitoring occasion may be performed in the order in which the start symbol of the PDCCH monitoring occasion is earlier. HARQ-ACKs corresponding to DCIs in the order of the index may be mapped to the HARQ-ACK codebook. The base station may transmit DCI (eg, DCI format) through up to one PDCCH monitoring occasion in each start symbol and each serving cell. The mapping order of HARQ-ACKs may be determined by further considering the positions of time resources (eg, start symbols) of PDSCHs corresponding to HARQ-ACKs.

Specifically, K HARQ-ACK(s) for K TB(s) scheduled through a certain DCI may be mapped to K bit(s) in the HARQ-ACK codebook. K may be a natural number. Alternatively, M HARQ-ACK(s) for M TB(s) among L TB(s) scheduled through a certain DCI may be mapped to M bit(s) in the HARQ-ACK codebook. L may be a natural number, and M may be a natural number less than or equal to L. The size of the HARQ-ACK codebook may be determined by the number of TB(s) that the base station actually schedules to the terminal through DCI. This operation may be referred to as (method 220).

On the other hand, the Type 2 HARQ-ACK codebook may include not only the HARQ-ACK corresponding to the DCI successfully received by the terminal, but also the HARQ-ACK corresponding to the DCI that the terminal has not received but estimated to have been transmitted by the base station. . According to the above-described PDSCH scheduling method, the number of TBs (eg, PDSCHs) scheduled by DCI may be dynamically changed. In this case, it may be difficult for the UE to know the number of TB(s) (eg, PDSCH(s)) scheduled by DCI, which is not received but is estimated to be transmitted by the base station. Therefore, when (Method 220) is used, it may be difficult for the UE to estimate the size of the HARQ-ACK codebook if some DCI is missed. As a result, the size of the HARQ-ACK codebook in the terminal may be different from the size of the HARQ-ACK codebook assumed by the base station (eg, the receiver of the base station), and transmission of the HARQ-ACK codebook may fail.

As a method for solving the above problem, with respect to the first DCI and the second DCI corresponding to the same HARQ-ACK codebook, information on the number of TBs (or PDSCHs) scheduled by the first DCI is the second DCI may be included in and transmitted to the terminal. For example, when the first DCI is transmitted first and the second DCI is transmitted later, the second DCI may include information about the number of TBs of the first DCI. Considering the above-mentioned indexing rule, the above-described operation can be generalized as follows. "When the first DCI is transmitted in a PDCCH monitoring occasion having a low index and the second DCI is transmitted in a PDCCH monitoring occasion having a high index", the second DCI includes information about the number of TBs in the first DCI can do. In addition, the second DCI may include information on whether the first DCI is actually transmitted (eg, downlink assignment index (DAI), counter DAI (C-DAI), total-DAI (T-DAI)). there is. According to this, even when the terminal misses the first DCI and receives the second DCI, the HARQ-ACK codebook can be correctly generated in consideration of the payload of the HARQ-ACK codebook corresponding to the first DCI. Information on the number of TBs (or PDSCHs) scheduled by the second DCI may be included in the first DCI and transmitted to the terminal. That is, each of the plurality of DCIs may include information about the number of TBs of the counterpart DCI. The first DCI may include information (eg, DAI, C-DAI, T-DAI) on whether the second DCI was actually transmitted. In this case, the UE may correctly generate the HARQ-ACK codebook even when the first DCI is received and the second DCI is missed. The above-described method may be equally applied to three or more DCIs corresponding to the same HARQ-ACK codebook. The method described above may be referred to as (method 230).

As another method for solving the above problem, for DCI(s) corresponding to the HARQ-ACK codebook, HARQ-ACK(s) corresponding to each DCI (or PDCCH monitoring occasion corresponding to each DCI) is The number of bits occupied by the HARQ-ACK codebook (hereinafter referred to as “B”) may be constant regardless of the number of TB(s) that are actually scheduled through each DCI. That is, when the number of DCI(s) corresponding to a certain HARQ-ACK codebook is A, the size of the corresponding HARQ-ACK codebook may be given as A×B. B may be a value associated with the number of TBs that may be scheduled by one DCI. For example, B may be determined as the maximum value of the number of TBs that can be scheduled by one DCI. As described above, the maximum value of the number of TBs per DCI may be set in the terminal. As another example, B may be determined as the largest value among the number(s) of TBs scheduled by entry(s) of an RRC table (eg, Table 2) configured in the terminal. Referring back to Table 2, 1 TB may be scheduled through entry 0, 2 TBs may be scheduled through entry 1, and 3 TBs may be scheduled through entry 2. In this case, according to the above-described method, B may be 3. The method described above may be referred to as (method 240). (Method 240) may be applied to each HARQ-ACK codebook generation and transmission.

Each DCI may schedule up to B TB(s). For example, some DCI may schedule C TB(s). C may be a natural number less than or equal to B. In this case, HARQ-ACK(s) corresponding to C TB(s) may be mapped to C bit(s) among B bits corresponding to the corresponding DCI in the HARQ-ACK codebook. When C<B, HARQ-ACK may not be mapped to the remaining (B-C) bits corresponding to DCI in the HARQ-ACK codebook. The UE may set the remaining (B-C) bits in the HARQ-ACK codebook to a value (eg, “0” or “1”) agreed to in advance with the base station. Alternatively, the UE may map the ACK to the remaining (B-C) bits in the HARQ-ACK codebook. Alternatively, the UE may map the NACK to the remaining (B-C) bits in the HARQ-ACK codebook.

7 is a conceptual diagram illustrating a first embodiment of a method for configuring a HARQ-ACK codebook for multiple PDSCH scheduling.

Referring to FIG. 7 , the base station may transmit first DCI to fourth DCI to the terminal. The UE may successfully receive the first DCI, the third DCI, and the fourth DCI, and may not successfully receive the second DCI. Even when the reception of the second DCI fails, the terminal may find out that the base station has transmitted the second DCI to the terminal through signaling from the base station (eg, DAI, C-DAI, T-DAI, etc.). The UE may acquire scheduling information of the first PDSCH including the first TB and the scheduling information of the second PDSCH including the second TB through the first DCI, and the second PDSCH including the third TB through the third DCI The scheduling information of the 3 PDSCH may be acquired, and the scheduling information of the fourth PDSCH including the fourth TB may be acquired through the fourth DCI. HARQ-ACKs corresponding to the first to fourth TBs may be transmitted to the base station at the same time point (eg, slot n+3). This operation may be performed by the above-described HARQ-ACK timing indication method and HARQ-ACK transmission time determination method.

HARQ-ACKs corresponding to the first to fourth TBs may be included in the same HARQ-ACK codebook. According to (Method 240), each DCI (or PDCCH monitoring occasion corresponding to each DCI) may correspond to B bits in the HARQ-ACK codebook, and B may be 3. For example, the embodiment may be applied to a terminal in which Table 2 (eg, RRC table) is configured. Referring to FIG. 7 , 3 bits corresponding to each of the first to fourth DCIs may sequentially correspond to the HARQ-ACK codebook, and the size of the HARQ-ACK codebook may be 12 (=4×3) bits.

According to the method described above, each DCI can schedule 3 or less TB(s). Two HARQ-ACKs for two TBs scheduled by the first DCI are bits corresponding to the first DCI in the HARQ-ACK codebook, b ₀ , b ₁ , and ₂ bits (eg For example, it may be mapped to b ₀ and b ₁ ). The terminal may allocate a value previously agreed with the base station to the remaining one bit (eg, b ₂ ) corresponding to the first DCI in the HARQ-ACK codebook. One HARQ-ACK for one TB scheduled by the third DCI is one bit of b ₆ , b ₇ , and b ₈ in the HARQ-ACK codebook. b ₆ ) can be mapped. The terminal may allocate a value previously agreed with the base station to the remaining two bits (eg, b ₇ and b ₈ ) corresponding to the third DCI in the HARQ-ACK codebook. One HARQ-ACK for one TB scheduled by the 4th DCI is the bits corresponding to the 4th _DCI in the _{HARQ -} ACK codebook. One bit (eg, b ₉ ) can be mapped. The terminal may allocate a value previously agreed with the base station to the remaining two bits (eg, b ₁₀ and b ₁₁ ) corresponding to the fourth DCI in the HARQ-ACK codebook. On the other hand, since the UE fails to receive the second DCI, the HARQ-ACK may not be mapped to 3 bits b ₃ , b ₄ , and b ₅ corresponding to the second DCI in the HARQ-ACK codebook. Alternatively, the terminal may allocate a value (eg, NACK or a bit value corresponding to NACK) previously agreed with the base station to three bits corresponding to the second DCI in the HARQ-ACK codebook.

The above-described method can be equally applied to the SPS. For example, in the above-described embodiment, PDSCH(s) and TB(s) scheduled by one DCI are scheduled (or received) within one SPS period (or received) to PDSCH(s) and TB(s). Each can respond. The UE may transmit HARQ-ACK(s) for the TB(s) scheduled within one SPS period to the base station using the above-described method.

On the other hand, the HARQ-ACK of the TB scheduled by the dynamic grant (eg, C-RNTI, MCS-C-RNTI) and the HARQ-ACK of the TB scheduled by the SPS (eg, CS-RNTI) are the same It may be included in the HARQ-ACK codebook. In this case, the above-described method can be applied to both mapping of HARQ-ACK by dynamic scheduling and HARQ-ACK by SPS. For example, if (Method 240) is used, in dynamic scheduling each DCI may correspond to a payload of B bits in the HARQ-ACK codebook, and each SPS period in SPS is a payload of B bits in the HARQ-ACK codebook can respond to That is, the number of downlink TB(s) that can be scheduled in one SPS period may not exceed B, and the number of HARQ-ACK bits corresponding to one SPS period may be B. For example, when B=3, each DCI(s) and SPS period(s) associated with a certain HARQ-ACK codebook may correspond to a 3-bit payload in the corresponding HARQ-ACK codebook. Similar to the embodiment of FIG. 7 , when the number of TBs transmitted within one SPS period is less than 3, the HARQ-ACK(s) for the TB(s) are 3 bits in the HARQ-ACK codebook may be mapped to some of them.

Alternatively, the HARQ-ACK of the TB scheduled by the dynamic grant (eg, C-RNTI, MCS-C-RNTI) and the HARQ-ACK of the TB scheduled by the SPS (eg, CS-RNTI) When included in the same HARQ-ACK codebook, the above-described method may be applied to HARQ-ACK by dynamic scheduling, and the above-described method may not be applied to HARQ-ACK by SPS. For example, when (Method 240) is used, in dynamic scheduling, each DCI may correspond to a B-bit payload in the HARQ-ACK codebook, and each SPS period in the SPS is a D-bit payload in the HARQ-ACK codebook. can respond to Here, D may mean the number of downlink TBs transmitted in each SPS period. D may be a natural number less than or equal to B. Alternatively, it may be permissible for D to be set to have a value greater than B. According to the method, the number of bits occupied by each DCI and the number of bits occupied by each SPS period in the HARQ-ACK codebook may be the same or different from each other.

HARQ-ACK of TB scheduled by dynamic grant (eg, C-RNTI, MCS-C-RNTI) and HARQ-ACK of DCI indicating release of SPS PDSCH may be included in the same HARQ-ACK codebook. Also in this case, a method similar to the method described above may be used. For example, when (Method 240) is used, the DCI indicating the release of the SPS PDSCH may correspond to the B bit in the HARQ-ACK codebook. HARQ-ACK for DCI may be 1 bit, and when B>1, HARQ-ACK of 1 bit may be mapped to some of B bits in the HARQ-ACK codebook. Alternatively, the DCI indicating the release of the SPS PDSCH may correspond to 1 bit in the HARQ-ACK codebook regardless of the B value. For example, 1-bit HARQ-ACK for DCI indicating release of SPS PDSCH may be mapped to 1-bit in the HARQ-ACK codebook.

In general, the above-described method is a HARQ-ACK of a TB scheduled by a dynamic grant (eg, C-RNTI, MCS-C-RNTI), a TB scheduled by an SPS (eg, CS-RNTI) When two or more HARQ-ACKs from among HARQ-ACK and HARQ-ACK of DCI indicating release of SPS PDSCH are included in the same HARQ-ACK codebook, the same or similar application may be applied. For example, when three HARQ-ACKs are included in the same HARQ-ACK codebook, each of the scheduling DCI, the SPS period, and the SPS release DCI may correspond to the B bit, the D bit, and the E bit in the HARQ-ACK codebook. there is.

[Type 1 HARQ-ACK Codebook]

When the type 1 HARQ-ACK codebook is used, the terminal is likely to be transmitted at a specific time (eg, slot, subslot) from candidate TB(s) that are likely to be scheduled (ie, received) from the base station. HARQ-ACK(s) may be estimated, the HARQ-ACK(s) may be mapped to the HARQ-ACK codebook, and the HARQ-ACK codebook may be transmitted at a specific time. For single PDSCH scheduling, each candidate TB may be transmitted on one or more PDSCH(s). One or more PDSCH(s) corresponding to one TB may be referred to as “candidate PDSCH reception”, “candidate PDSCH occasion”, “PDSCH occasion”, and the like. One HARQ-ACK may be mapped to one bit of the codebook for each PDSCH occasion. When repeated PDSCH transmission is used for a TB, the HARQ-ACK timing of the TB may be defined based on the reception time of the last PDSCH occasion corresponding to the TB. PDSCH occasions mapped to the same HARQ-ACK codebook may be simultaneously received by the UE. For example, time resources (eg, symbols) of PDSCH occasions mapped to the same HARQ-ACK codebook may not overlap each other.

In the case of multiple PDSCH scheduling, PDSCH occasions may be defined in different ways. For example, when (Method 200) is used, PDSCH occasion is TB(s) likely to be scheduled through one downlink DCI (or TB(s) likely to be transmitted within one SPS period) )) corresponding to the PDSCH(s). A PDSCH occasion may include N1 TB(s), and N1 HARQ-ACK(s) corresponding to N1 TB(s) may be mapped to N1 bit(s) in the HARQ-ACK codebook. . N1 may be a natural number. N1 may be the same or different for each PDSCH occasion, and a plurality of PDSCH occasions may correspond to a different number of bit(s) or the same number of bit(s) in the HARQ-ACK codebook. According to (Method 200), TB(s) scheduled through one DCI may be included in the same HARQ-ACK codebook at the same time, and the same HARQ-ACK codebook may be transmitted. The transmission time of the HARQ-ACK codebook may be defined based on the reception time of the last PDSCH among the PDSCH(s) constituting the PDSCH occasion.

8 is a conceptual diagram illustrating a second embodiment of a method for configuring a HARQ-ACK codebook for multi-PDSCH scheduling.

Referring to FIG. 8 , the UE may receive the configuration of the RRC table for PDSCH time domain resource allocation, and the RRC table may include two entries. Entry 0 may include two SLIVs, and according to the two SLIVs, scheduling of PDSCHs including two TBs may be indicated to the UE. Entry No. 1 may include one SLIV, and according to one SLIV, scheduling of PDSCH(s) including one TB may be indicated to the UE. The UE may receive the configuration of K1 candidate values {1, 2} indicating the HARQ-ACK timing. At least one of the candidate values of K1 may be dynamically indicated to the UE by DCI.

According to an embodiment, four PDSCH occasions may be mapped to the HARQ-ACK codebook transmitted in slot n+3. The first PDSCH occasion may include a PDCCH of slot n and a first PDSCH and a second PDSCH corresponding to candidate TBs (eg, first TB and second TB) that may be scheduled through entry 0. there is. According to (Method 200), HARQ-ACKs of candidate TBs of the first PDSCH occasion are mapped to two bits (eg, b ₀ and b ₁ ) in the HARQ-ACK codebook based on the timing of K1=2. can be The second PDSCH occasion includes a PDCCH of slot n+1 and a third PDSCH and a fourth PDSCH corresponding to candidate TBs (eg, third TB and fourth TB) that can be scheduled through entry 0 can do. According to (Method 200), HARQ-ACKs of candidate TBs of the second PDSCH occasion are mapped to two bits (eg, b ₂ and b ₃ ) in the HARQ-ACK codebook based on the timing of K1=1 can be The third PDSCH occasion may be a PDCCH of slot n+1 and a fifth PDSCH corresponding to a candidate TB (eg, a fifth TB) that may be scheduled through entry #1. The HARQ-ACK of the candidate TB of the third PDSCH occasion may be mapped to one bit (eg, b ₄ ) in the HARQ-ACK codebook based on the timing of K1=2. The fourth PDSCH occasion may be a PDCCH of slot n+2 and a sixth PDSCH corresponding to a candidate TB (eg, a sixth TB) that may be scheduled through entry 1. The HARQ-ACK of the candidate TB of the fourth PDSCH occasion may be mapped to one bit (eg, b ₅ ) in the HARQ-ACK codebook based on the timing of K1=1. As a result, the size of the HARQ-ACK codebook may be 6 bits. The UE may map HARQ-ACK information reflecting the reception result of the PDSCH occasion(s) actually received among the PDSCH occasions to the HARQ-ACK codebook, and the PDSCH occasions not actually received among PDSCH occasions ( ), predefined information or values (eg, NACK, ACK, “0”, or “1”) may be mapped to the HARQ-ACK codebook.

According to another embodiment, at least some of the PDSCH occasions described in the second embodiment of FIG. 8 may be an SPS PDSCH, and the SPS PDSCH is semi-permanently scheduled by "SPS configuration" or "SPS configuration and DCI indication" can be Even in this case, the above-described method of setting the HARQ-ACK codebook may be equally applied.

Meanwhile, the UE may not expect to receive a scheduling indication or configuration of overlapping PDSCHs (eg, unicast PDSCHs). Referring to FIG. 8 , the second PDSCH occasion (ie, the third PDSCH) and the third PDSCH occasion (ie, the fifth PDSCH) may overlap each other. In this case, the UE may not expect to receive scheduling information of both the second PDSCH occasion and the third PDSCH occasion, and receives any one of the second PDSCH occasion and the third PDSCH occasion. It can be regarded as a possible PDSCH occasion. In this case, the UE may map any one of the second PDSCH occasion and the third PDSCH occasion to the HARQ-ACK codebook according to a predetermined priority rule. For example, a PDSCH occasion corresponding to a lower (or higher) entry number may have a higher priority. A PDSCH occasion corresponding to an earlier (or later) PDCCH may have a higher priority. A PDSCH occasion corresponding to a lower (or higher) serving cell ID may have a higher priority. In an embodiment, according to the method, the UE may consider that the second PDSCH occasion corresponding to entry 0 has a higher priority than the third PDSCH occasion corresponding to entry 1, and the second PDSCH occasion The occasion may be mapped to the HARQ-ACK codebook, and the third PDSCH occasion may not be mapped to the HARQ-ACK codebook. As a result, the size of the HARQ-ACK codebook may be 5 bits.

For another example, when (Method 210) is used, the PDSCH occasion is TB(s) likely to be scheduled through one downlink DCI (or TB likely to be transmitted within one SPS period ( )) may mean PDSCH(s) corresponding to at least some TB(s). For example, one DCI may schedule N1 TB(s), and any PDSCH occasion corresponding to one DCI includes PDSCH(s) including N2 TB(s) among the N1 TB(s). ) can be N2 may be a natural number less than or equal to N1. N2 HARQ-ACK(s) corresponding to N2 TB(s) may be mapped to N2 bit(s) in the HARQ-ACK codebook. One or more PDSCH occasions may correspond to one DCI. For example, if 1 DCI schedules 3 TB(s), the first 2 TB(s) may be mapped to the first PDSCH occasion, and the last 1 TB may be mapped to the second PDSCH occasion. can be TB(s) mapped to each PDSCH occasion may be TB(s) having the same HARQ-ACK feedback time point. According to the above method, the HARQ-ACK(s) of each PDSCH occasion may be mapped to the HARQ-ACK codebook according to the HARQ-ACK feedback timing, and the corresponding HARQ-ACK codebook may be transmitted to the base station.

Referring back to FIG. 6( a ), the UE may receive scheduling information of the first PDSCH including the first TB and the scheduling information of the second PDSCH including the second TB through DCI, and the first TB HARQ-ACK for and HARQ-ACK for the second TB may be transmitted to the base station at different time points. In this case, the first PDSCH and the second PDSCH may be regarded as different PDSCH occasions. Referring back to FIG. 6(b), the UE may receive scheduling information of the first PDSCH including the first TB and the scheduling information of the second PDSCH including the second TB through DCI, and the first TB HARQ-ACK for and HARQ-ACK for the second TB may be transmitted to the base station at the same time. In this case, the first PDSCH and the second PDSCH may be considered to be included in the same PDSCH occasion.

On the other hand, if the preset condition is satisfied even when using the type 1 HARQ-ACK codebook is set in the terminal, the terminal feeds back the HARQ-ACK according to a separate method instead of the above-described method of setting the type 1 HARQ-ACK codebook. can The preset conditions are "when the terminal receives one DCI corresponding to a specific HARQ-ACK feedback time", "when one DCI is a specific DCI format (eg, fallback DCI format, DCI format 1_0, etc.)" , "When the C-DAI field included in one DCI has a specific value (eg, 1)", or "When one DCI is transmitted in a primary cell (PCell)" at least one may include DCI may schedule one TB or multiple TBs. When a preset condition is satisfied, the UE may generate only HARQ-ACK(s) for TB(s) scheduled through one DCI, and only the generated HARQ-ACK(s) at a specific HARQ-ACK feedback time can be transmitted to the base station. For example, when one DCI schedules two TBs, the terminal may transmit 2-bit HARQ-ACKs for the two TBs to the base station through an uplink resource. Accordingly, the amount of information of HARQ-ACK transmitted from the terminal to the base station may be reduced.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (20)

A method of operating a terminal in a communication system, comprising:
receiving downlink control information (DCI) from a base station;
identifying a plurality of start and length indicator values (SLIVs) indicated by a time domain resource allocation field included in the DCI;
determining a plurality of physical downlink shared channel (PDSCH) resources based on the plurality of SLIVs;
receiving a plurality of PDSCHs from the base station on the plurality of PDSCH resources; and
and transmitting a plurality of hybrid automatic repeat request-acknowledgements (HARQ-ACKs) that are responses to the plurality of PDSCHs to the base station. The method according to claim 1,
The plurality of HARQ-ACKs are transmitted through one physical uplink control channel (PUCCH) resource, and the one PUCCH resource is indicated by HARQ-ACK timing information included in the DCI. The method according to claim 1,
The plurality of HARQ-ACKs are included in one HARQ-ACK codebook, and the one HARQ-ACK codebook is transmitted to the base station through one PUCCH resource. 4. The method according to claim 3,
The size of the one HARQ-ACK codebook is determined based on a specific value instead of the number of the plurality of PDSCHs, and the specific value is the maximum number of PDSCHs schedulable by one DCI. 5. The method according to claim 4,
The specific value is B, the number of the plurality of PDSCHs is C, B bits included in the one HARQ-ACK codebook correspond to the one DCI, and among the B bits, the plurality of C bits HARQ-ACKs of are mapped, predefined values are mapped to the remaining (BC) bits among the B bits, B is a natural number, and C is an integer of 0 or more and B or less. 4. The method according to claim 3,
The transmission time of the one HARQ-ACK codebook is determined based on the reception time of the last PDSCH among the plurality of PDSCHs. The method according to claim 1,
The number of the plurality of PDSCHs is implicitly indicated by the number of the plurality of SLIVs. The method according to claim 1,
The method of operation of the terminal,
Further comprising the step of receiving the configuration information of the time resource list from the base station,
The time resource list includes a plurality of entries indicating a time resource, each of one or more entries among the plurality of entries indicates two or more SLIVs, and the time domain resource allocation field includes the one or more entries Indicating one entry from among, the operating method of the terminal. The method according to claim 1,
The method of operation of the terminal,
The method of operating a terminal further comprising transmitting information indicating the maximum number of schedulable PDSCHs in one slot to the base station. The method according to claim 1,
The DCI supports both single PDSCH scheduling and multiple PDSCH scheduling, when the single PDSCH scheduling is performed, the DCI schedules one PDSCH, and when the multiple PDSCH scheduling is performed, the DCI is the plurality of PDSCHs Scheduling them, the operating method of the terminal. A method of operating a base station in a communication system, comprising:
transmitting downlink control information (DCI) to the terminal;
Transmitting a plurality of PDSCHs from a plurality of physical downlink shared channel (PDSCH) resources determined based on a plurality of start and length indicator values (SLIV) indicated by a time domain resource allocation field included in the DCI to the terminal to do; and
Receiving a plurality of hybrid automatic repeat request-acknowledgements (HARQ-ACKs) in response to the plurality of PDSCHs from the terminal, the method of operating a base station. 12. The method of claim 11,
The plurality of HARQ-ACKs are received through one physical uplink control channel (PUCCH) resource, and the one PUCCH resource is indicated by HARQ-ACK timing information included in the DCI. 12. The method of claim 11,
The plurality of HARQ-ACKs are included in one HARQ-ACK codebook, and the one HARQ-ACK codebook is received through one PUCCH resource. 14. The method of claim 13,
The size of the one HARQ-ACK codebook is determined based on a specific value instead of the number of the plurality of PDSCHs, and the specific value is the maximum number of PDSCHs schedulable by one DCI. 15. The method of claim 14,
The specific value is B, the number of the plurality of PDSCHs is C, B bits included in the one HARQ-ACK codebook correspond to the one DCI, and among the B bits, the plurality of C bits HARQ-ACKs of are mapped, predefined values are mapped to the remaining (BC) bits among the B bits, B is a natural number, and C is an integer of 0 or more and B or less. 14. The method of claim 13,
The reception time of the one HARQ-ACK codebook is determined based on the transmission time of the last PDSCH among the plurality of PDSCHs. 12. The method of claim 11,
The number of the plurality of PDSCHs is implicitly indicated by the number of the plurality of SLIVs. 12. The method of claim 11,
The method of operation of the base station,
Further comprising the step of transmitting the configuration information of the time resource list to the terminal,
The time resource list includes a plurality of entries indicating a time resource, each of one or more entries among the plurality of entries indicates two or more SLIVs, and the time domain resource allocation field includes the one or more entries Indicating one entry from among, the base station operating method. 12. The method of claim 11,
The method of operation of the base station,
The method of operating a base station further comprising the step of receiving information indicating the maximum number of schedulable PDSCHs in one slot from the terminal. 12. The method of claim 11,
The DCI supports both single PDSCH scheduling and multiple PDSCH scheduling, when the single PDSCH scheduling is performed, the DCI schedules one PDSCH, and when the multiple PDSCH scheduling is performed, the DCI is the plurality of PDSCHs A method of operating a base station for scheduling them.

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