KR20210139153A - METHOD AND APPARATUS FOR transmitting and receiving downlink control channel in communication system - Google Patents

Abstract

Disclosed are a transmitting and receiving method of a downlink control channel in a communication system and a device thereof. An operation method of a terminal comprises the steps of: receiving setup information of a resource set for a PDCCH monitoring operation from a base station; performing the PDCCH monitoring operation in the resource set; receiving at least one DCI including scheduling information of a first PDSCH by the PDCCH monitoring operation; and receiving the first PDSCH based on the scheduling information.

Description

Method and apparatus for transmitting and receiving a downlink control channel in a communication system {METHOD AND APPARATUS FOR transmitting and receiving downlink control channel in communication system}

The present invention relates to a technology for transmitting and receiving a signal in a communication system, and more particularly, to a technology for transmitting and receiving a downlink control channel.

In order to activate the ecosystem of the 4th industrial revolution, new and various communication infrastructure markets are being pioneered, and for this purpose, a more advanced communication system (eg, a long term evolution (LTE) communication system) than a conventional communication system , a new radio (NR) communication system) is being considered. The NR communication system may support a frequency band of 6 GHz or higher 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 may include enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), massive Machine Type Communication (mMTC), and the like. There is a need for communication technologies to satisfy the various requirements of the industry.

Meanwhile, in a communication system (eg, an NR communication system), the base station may transmit a physical downlink control channel (PDCCH) including scheduling information to the terminal, and based on the scheduling information included in the PDCCH, a physical downlink shared channel (PDSCH). ) can be transmitted to the terminal. The same PDCCH may be transmitted by different transmission and reception points (TRPs). In this case, methods for improving the reception performance of the PDCCH are needed.

An object of the present invention to solve the above problems is to provide a method and apparatus for transmitting and receiving a downlink control channel in a communication system.

In order to achieve the above object, a method of operating a terminal according to a first embodiment of the present invention includes the steps of receiving configuration information of a resource set for a PDCCH monitoring operation from a base station, and performing the PDCCH monitoring operation on the resource set. , receiving at least one DCI including scheduling information of a first PDSCH by the PDCCH monitoring operation, and receiving the first PDSCH based on the scheduling information, wherein the resource set is a PDCCH a first search space and a second search space for repeated transmission, wherein the first search space is used for transmission of a first DCI, the second search space is used for transmission of a second DCI, and the at least one DCI is at least one of the first DCI and the second DCI, the first DCI and the second DCI include the same payload, and the format of the first DCI is the format of the second DCI and same.

Here, the first DCI may be received based on information on the QCL of the first CORESET combined with the first search space, and the second DCI is in the QCL of the second CORESET combined with the second search space. information about the first CORESET and the information on the QCL of the second CORESET may be independently determined from each other.

Here, when the first CORESET combined with the first search space is the same as the second CORESET combined with the second search space, the first DCI and the second DCI may be received based on information about the same QCL. have.

Here, the first PDSCH may be received based on TCI status information for the first PDSCH, and the configuration information of the first CORESET combined with the first search space includes the TCI status information in the first DCI. It may include first information indicating whether or not the second CORESET is combined with the second search space, and may include second information indicating whether the TCI state information is included in the second DCI. and the first information and the second information may be the same.

Here, when the first DCI and the second DCI do not include the TCI state information for the first PDSCH, the reception operation of the first PDSCH is performed in which the first PDSCH is combined with the first search space. CORESET and the second CORESET combined with the second search space may be performed based on the assumption that the CORESET having a smaller ID and QCL are performed.

Here, when the number of symbols between at least one end symbol of the first DCI end symbol and the second DCI end symbol and the first PDSCH start symbol is less than or equal to a reference value, the reception operation of the first PDSCH is the first It may be performed based on the assumption that the PDSCH is QCLed with one CORESET in the most recent slot including one or more CORESETs.

Here, the one CORESET may be a first CORESET combined with the first search space or a second CORESET combined with the second search space.

Here, the first search space and the second search space may be set to the same search space set type, and the same search space set type may be a terminal-specific search space or a common search space.

Here, the first PDCCH including the first DCI may be transmitted through a first PDCCH candidate of the first search space, and the second PDCCH including the second DCI may be a second PDCCH of the second search space. It may be transmitted through a candidate, and the first PDCCH candidate and the second PDCCH candidate may have the same CCE aggregation level and the same PDCCH candidate index.

Here, the first PDCCH candidate may be configured to be connected to the second PDCCH candidate for the repeated PDCCH transmission.

Here, the performing the PDCCH monitoring operation includes performing the monitoring operation of the second PDCCH candidate without performing the monitoring operation of the first PDCCH candidate when the first PDCCH candidate satisfies a predefined condition. may include

Here, the predefined conditions include a condition in which the first PDCCH candidate overlaps an SS/PBCH) block, a condition in which the first PDCCH candidate overlaps a PRACH resource, and a condition in which the first PDCCH candidate overlaps an uplink symbol. , and a condition in which the first search space is excluded from mapping by a search space mapping rule.

In order to achieve the above object, a method of operating a base station according to a second embodiment of the present invention includes transmitting configuration information of a resource set for a PDCCH monitoring operation to a terminal, and scheduling information of a first PDSCH in the resource set. transmitting at least one DCI to the terminal, and transmitting the first PDSCH to the terminal based on the scheduling information, wherein the resource set includes a first search space for repeated PDCCH transmission and a 2 search spaces, wherein the first search space is used for transmission of a first DCI, the second search space is used for transmission of a second DCI, and the at least one DCI includes the first DCI and the second DCI. At least one DCI of 2 DCIs, the first DCI and the second DCI include the same payload, and the format of the first DCI is the same as that of the second DCI.

Here, the information on the QCL of the first CORESET combined with the first search space may be determined independently of the information on the QCL of the second CORESET combined with the second search space.

Here, the configuration information of the first CORESET combined with the first search space may include first information indicating whether TCI state information for the first PDSCH is included in the first DCI, and the second discovery The configuration information of the second CORESET combined with the space may include second information indicating whether the TCI state information is included in the second DCI, and the first information may be the same as the second information.

Here, when the first DCI and the second DCI do not include the TCI state information for the first PDSCH, the reception operation of the first PDSCH in the terminal is performed by combining the first PDSCH with the first search space. The first CORESET and the second CORESET combined with the second search space may be performed based on the assumption that the CORESET having a smaller ID is QCLed.

Here, when the number of symbols between at least one end symbol of the first DCI end symbol and the second DCI end symbol and the first PDSCH start symbol is less than or equal to a reference value, the terminal receives the first PDSCH operation It may be performed based on the assumption that the first PDSCH is QCL with one CORESET in the most recent slot including one or more CORESETs.

Here, the first search space and the second search space may be set to the same search space set type, and the same search space set type may be a terminal-specific search space or a common search space.

Here, the first PDCCH including the first DCI may be transmitted through a first PDCCH candidate of the first search space, and the second PDCCH including the second DCI may be a second PDCCH of the second search space. It may be transmitted through a candidate, and the first PDCCH candidate and the second PDCCH candidate may have the same CCE aggregation level and the same PDCCH candidate index.

Here, the first PDCCH candidate may be configured to be connected to the second PDCCH candidate for the repeated PDCCH transmission.

According to the present invention, the same physical downlink control channel (PDCCH) may be repeatedly transmitted. The same PDCCH may be transmitted by different transmission and reception points (TRPs). When all of the repeatedly transmitted PDCCHs are received, the UE may perform a soft combining operation on the received PDCCHs. Even when only one PDCCH is received among repeatedly transmitted PDCCHs, the UE may receive a physical downlink shared channel (PDSCH) based on the received DCI. According to the above-described operations, the reception performance of the PDCCH and the PDSCH may be improved.

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 PDCCH transmission method according to a first scenario.
4 is a conceptual diagram illustrating a first embodiment of a PDCCH transmission method according to second and third scenarios.
5A is a conceptual diagram illustrating a first embodiment of a method for scheduling a PDSCH using multiple PDCCHs.
5B is a conceptual diagram illustrating a second embodiment of a PDSCH scheduling method using multiple PDCCHs.
6A is a conceptual diagram illustrating a third embodiment of a method for scheduling a PDSCH using multiple PDCCHs.
6B is a conceptual diagram illustrating a fourth embodiment of a method for scheduling a PDSCH using multiple PDCCHs.
7 is a conceptual diagram illustrating a first embodiment of a method for concatenating a PDCCH search space set for repeated PDCCH transmission.
8A is a conceptual diagram illustrating a second embodiment of a method of concatenating a PDCCH search space set for repeated PDCCH transmission.
8B is a conceptual diagram illustrating a third embodiment of a method of concatenating a PDCCH search space set for repeated PDCCH transmission.
9 is a conceptual diagram illustrating a first embodiment of a PDSCH rate matching method.
10A is a conceptual diagram illustrating a first embodiment of a method for allocating PDCCH and PDSCH resources.
10B is a conceptual diagram illustrating a second embodiment of a method for allocating PDCCH and PDSCH resources.
10C is a conceptual diagram illustrating a third embodiment of a method for allocating PDCCH and PDSCH resources.
11A is a conceptual diagram illustrating a first embodiment of a HARQ-ACK transmission method for the same TB and a plurality of PDSCHs.
11B is a conceptual diagram illustrating a second embodiment of a HARQ-ACK transmission method for the same TB and a plurality of PDSCHs.
12 is a conceptual diagram illustrating a first embodiment of a method for setting an HARQ frame.
13 is a conceptual diagram illustrating a first embodiment of a method of indicating HARQ-ACK transmission timing according to (Method 200).
14 is a conceptual diagram illustrating a third embodiment of a HARQ-ACK transmission method for the same TB and a plurality of PDSCHs.

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 a specific embodiment, 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.

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

The terms used 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 contents 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 sense 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. The plurality of communication nodes 110 to 130 include a code division multiple access (CDMA) technology, a wideband CDMA (WCDMA) technology, a time division multiple access (TDMA) technology, a frequency division multiple access (FDMA) technology, orthogonal frequency division (OFDM). 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 component 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. have. 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 the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is transmitted to the core network can be sent to

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. A plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) each of the terminals (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 a signal (eg, a downlink control channel) in a communication system will be described. The following embodiments may be applied to an NR communication system. In addition, the following embodiments may be applied not only to the NR communication system but also to other communication systems (eg, an LTE communication system, a fifth generation (5G) communication system, a sixth generation (6G) communication system, etc.).

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 method for configuring a pneumatology for a CP-OFDM based communication system. Adjacent 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, the frame structure of the 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 not match the length of the slot. The 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 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 by the downlink or uplink symbol, the terminal 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 base station and 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. RBs constituting one bandwidth portion may be continuous in the frequency domain. 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. The terminal operating in the RRC connected state may obtain configuration information of the bandwidth part from the 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 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 consecutive RBs 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 the 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 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 (or demodulation) of the PDCCH may be mapped to 3 REs among 12 REs constituting the REG, and control information (eg, modulated DCI) is It may be mapped to the remaining 9 REs.

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 (or blind demodulation) 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 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.

The CORESET may be set in the terminal by the PBCH (eg, system information transmitted through the PBCH, a master information block (MIB)). 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 type1 (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. The UE may monitor the PDCCH candidate(s) for the CORESET set in the corresponding bandwidth part in the downlink active bandwidth part. Alternatively, the UE may monitor the PDCCH candidate(s) for the CORESET (eg, CORESET #0) configured in a downlink bandwidth part other than the corresponding bandwidth part in the downlink active 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 PDCCH candidate(s) or a set of resource regions occupied by PDCCH candidate(s). 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 itself 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 UE may periodically monitor the search space, and may monitor the search space at one or more time locations (eg, PDCCH monitoring occasion, CORESET) within one period.

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 or correspond to one CORESET. One CORESET may be logically combined with or correspond to one or more search space sets. A search space set for transmitting a common DCI or a group common DCI may be referred to as a common search space set (hereinafter, referred to as a “CSS set”). The common DCI or the group common DCI may include resource allocation information of PDSCH for transmission of system information, paging information, power control command, SFI, preemption indicator, and the like. In the case of an NR communication system, the common DCI may correspond to DCI formats 0_0, 1_0, etc., and a cyclic redundancy check (CRC) of the common DCI transmitted to the terminal is a system information-radio network temporary identifier (SI-RNTI), P-RNTI It may be scrambled by (paging-RNTI), random access-RNTI (RA-RNTI), temporary cell-RNTI (TC-RNTI), or the like. The group common DCI may correspond to DCI format 2_X (X=0, 1, 2, ??), etc., and the CRC of the group common DCI transmitted to the terminal may be scrambled by SFI-RNTI (slot format indicator-RNTI), etc. have. The CSS set may include Type 0, Type 0A, Type 1, Type 2, and Type 3 CSS sets.

The search space set for transmitting the UE-specific DCI may be referred to as a UE-specific search space set (hereinafter, referred to as a “USS set”). The UE-specific DCI may include scheduling and resource allocation information such as PDSCH, PUSCH, and PSSCH. In the case of the NR communication system, the terminal-specific DCI may correspond to DCI formats 0_1, 0_2, 1_1, 1_2, 3_0, 3_1, etc., and the CRC of the terminal-specific DCI transmitted to the terminal is C-RNTI, CS-RNTI (configured Scheduling-RNTI), MCS-C-RNTI (modulation and coding scheme-C-RNTI), etc. may be scrambled. Considering scheduling freedom or fallback transmission, UE-specific DCI may be transmitted even in the CSS set. In this case, the UE-specific DCI may be transmitted according to a DCI format corresponding to the common DCI. For example, the UE may monitor the PDCCH (eg, DCI formats 0_0, 0_1) in which CRC is scrambled with C-RNTI, CS-RNTI, MCS-C-RNTI, etc. in the CSS set.

The type 0 CSS set may be used for reception of DCI scheduling PDSCH including SIB1, and may be configured through PBCH or cell-specific RRC signaling. The ID of the type 0 CSS set may be assigned or set to 0. Type 0 CSS set can be logically combined with CORESET #0.

The UE may assume that the PDCCH DM-RS has a QCL relationship with some signal (eg, SS/PBCH block, CSI-RS, PDSCH DM-RS, PDCCH DM-RS, etc.). In addition, since the PDCCH has the same antenna port as the PDCCH DM-RS, the PDCCH and the PDCCH DM-RS may have a QCL relationship with each other. Therefore, the UE can obtain information about the large-scale propagation characteristics of the radio channel experienced by the PDCCH and the PDCCH DM-RS through the above-described QCL assumption, and use the obtained large-scale propagation characteristics to estimate the channel and form the receive beam. etc. can be used. QCL parameters include delay spread, Doppler spread, Doppler shift, average gain, average delay, spatial Rx parameter, etc. can The spatial reception parameter may correspond to characteristics such as a reception beam, a reception channel spatial correlation, and a transmission/reception beam pair. For convenience, the spatial reception parameter may be referred to as “spatial QCL”. The PDCCH may be used to mean including the PDCCH DM-RS, and saying that the PDCCH has a QCL relationship with a certain signal may include the meaning that the DM-RS of the PDCCH has a QCL relationship with a certain signal. A signal having a QCL relationship with the PDCCH or a resource thereof may be referred to as a QCL source, a QCL source signal, a QCL source resource, or the like.

PDCCHs transmitted in the same CORESET, a search space set corresponding to the same CORESET, and/or PDCCH monitoring occasions corresponding to the same CORESET may have the same QCL relationship. That is, the unit of aggregation in which the UE assumes the same QCL may be a CORESET, and the QCL assumption may be independent for each CORESET. In an embodiment, the QCL, QCL source, etc. of a certain CORESET may mean QCL, QCL source, etc. of the PDCCH received through the corresponding CORESET, respectively. Exceptionally, different QCL assumptions may be applied to search space sets corresponding to one CORESET. For example, a search space set for monitoring RA-RNTI (eg, Type 1 CSS set) and other search space sets may have different QCL relationships.

The QCL relationship or QCL assumption (eg, QCL source, QCL type, etc.) of CORESET may be determined by a predefined method. For example, the UE selects an SS/PBCH block and/or CSI-RS in which a PDCCH DM-RS received through a certain CORESET or a certain search space set is selected in the process of performing an initial access or random access procedure and a predefined QCL type It can be assumed to have a QCL relationship with Here, the QCL type may mean a set of one or more QCL parameter(s). Alternatively, the QCL relationship or QCL assumption (eg, QCL source, QCL type, etc.) of CORESET is signaling (eg, RRC signaling, medium access control (MAC) control element (CE) signaling, and DCI from the base station to the terminal. signaling, one or a combination of two or more). That is, the base station may set a transmission configuration information (TCI) state for CORESET in the terminal. In general, the TCI state is an ID of a signal (eg, QCL source of PDCCH DM-RS, QCL source resource) having a QCL relationship with a DM-RS (eg, PDCCH DM-RS) of a physical channel to which TCI is applied. and/or at least one QCL type thereof. The TCI state may include one or more {ID and/or QCL type}. For example, the base station may set one or more TCI state candidates for each CORESET through RRC signaling to the terminal, and one TCI state used for CORESET monitoring of the terminal from among the one or more TCI state candidates MAC signaling (or DCI signaling) ) to indicate or set. When there is one TCI state candidate configured by RRC signaling, the MAC signaling procedure (or DCI signaling procedure) may be omitted. The UE may perform a PDCCH monitoring and reception operation for the corresponding CORESET based on the TCI state setting information received from the base station.

Meanwhile, beam operation of a high frequency band and a low frequency band in a communication system may be different from each other. In a low frequency band (eg, a band below 6 GHz), since path loss of a signal due to a channel is relatively small, a signal may be transmitted/received using a beam having a wide beamwidth. In particular, in the case of a control channel, the entire coverage of a cell (or sector) may be covered even with a single beam. However, in a high-frequency band (eg, a band of 6 GHz or more) in which a signal path loss is large, beamforming by a large-scale antenna may be used to extend the signal reach. In addition, beamforming may be applied not only to a data channel but also to a common signal and a control channel. A communication node (eg, a base station) may form a beam having a small beam width through a plurality of antennas, and use a plurality of beams having different directional directivity to cover the entire spatial area of a cell (or sector). Thus, the signal can be transmitted and received multiple times. An operation of repeatedly transmitting a signal on a plurality of time resources using a plurality of beams may be referred to as a beam sweeping operation. A system for transmitting a signal using a plurality of beams having such a narrow beam width may be referred to as a multi-beam system.

The multi-beam system may operate based on beam management. The UE may measure the beam quality with respect to the received signal (eg, SS/PBCH block, CSI-RS, etc.), and may report the measurement result of the beam quality to the base station. For example, the UE calculates beam quality measurements such as reference signal received power (RSRP) and signal-to-interference-plus-noise ratio (SINR) for each beam (eg, each signal, each resource). and the optimal beam(s) and corresponding measurement value(s) may be reported to the base station. The base station may determine the transmission beam for the terminal based on the measurement information of the beam quality received from the terminal. In addition, the base station based on the measurement information of the beam quality received from the terminal, the terminal's physical signal and channel (eg, PDCCH, PDSCH, CSI-RS, PUCCH, PUSCH, SRS, PRACH, etc.) for the reception of TCI state can be set in the terminal.

A multiple beam may be formed by a plurality of TRPs and/or panels. Hereinafter, TRP and panel may be collectively referred to as TRP. TRPs may be disposed based on different spatial locations, antenna shapes, radiation directions, and the like. Therefore, different beams (eg, a transmit beam, a receive beam, and a transmit/receive beam pair) may be formed in each channel formed between the TRPs and the terminal. The base station may perform multi-beam transmission using multiple TRPs, and transmission reliability may be improved by a beam selection gain or a beam diversity gain. The multiple TRP transmission scheme may be referred to as coordinated multipoint (CoMP). TRPs participating in multiple TRP transmission may belong to the same base station or the same serving cell. Alternatively, TRPs participating in multiple TRP transmission may belong to different base stations or different serving cells. As a backhaul environment between TRPs, an ideal backhaul and a non-ideal backhaul may be considered. It may be difficult to apply joint scheduling between TRPs connected by non-ideal backhaul.

[Multi-TRP-based PDCCH transmission method]

Hereinafter, multiple TRP transmission methods for increasing PDCCH transmission reliability will be described. In embodiments, unless otherwise specified, “beam” may mean “transmission beam”, “reception beam”, and/or “transmission beam pair”. Also, “beam”, “transmission beam”, “reception beam”, and “transmission/reception beam pair” may have the same meaning. In embodiments, the base station may transmit the PDCCH using a plurality of TRPs, and the terminal may properly receive the PDCCH. Specifically, the base station and the terminal may perform multi-beam-based PDCCH transmission based on the following scenarios.

According to the first scenario, DCI may be transmitted through one CORESET and one PDCCH. The plurality of TRPs may transmit DCI to the UE through one PDCCH on the same resource (eg, the same CORESET, the same search space set, and the same PDCCH candidate). For example, one PDCCH that the UE receives in one CORESET may be transmitted from a plurality of TRPs. This operation may correspond to a transmission scheme such as non-coherent joint transmission (JT) or single frequency network (SFN).

3 is a conceptual diagram illustrating a first embodiment of a PDCCH transmission method according to a first scenario.

Referring to FIG. 3 , the UE may acquire DCI by receiving the first PDCCH from the first and second TRPs. The first PDCCH may be transmitted through a first CORESET (or a search space set corresponding to the first CORESET, PDCCH monitoring occasion, etc.) configured in the terminal. The UE may receive the first PDCCH based on the QCL assumption for the first CORESET. A QCL may include a spatial QCL. That is, the UE may receive a PDCCH transmitted from a plurality of TRPs using one reception beam. When beams formed from the first and second TRPs are different from each other, PDCCH decoding performance may be improved due to the beam diversity effect. A sufficient condition for operation based on the first scenario may be that a transmission beam or a transmission/reception beam pair formed from the first and second TRPs should correspond to one reception beam of the terminal.

According to the second scenario, DCI may be transmitted through a plurality of PDCCHs and/or a plurality of CORESETs. A plurality of TRPs can transmit DCI to the UE through different PDCCHs on independent (or separate) resources (eg, different CORESETs, different search space sets, or different PDCCH candidates). have. Independent resources may overlap in time domain and/or frequency domain. The UE may receive a plurality of PDCCHs from a plurality of CORESETs, and may obtain the same DCI through the plurality of received PDCCHs. Here, the same DCI transmitted from a plurality of PDCCHs may mean that the payload of DCI before encoding is the same, and a series of processes such as channel coding and resource mapping may be applied the same or differently for each TRP. . Strictly speaking, the UE may acquire a plurality of DCIs through a plurality of PDCCHs, and the plurality of DCIs may have the same payload. The above-described method may be referred to as repeated PDCCH transmission or repeated DCI transmission.

In an embodiment, the DCI may mean each copy of the DCI repeatedly transmitted depending on the case, or may mean a DCI payload. DCI may correspond to one or more downlink or uplink HARQ processes, and may schedule one or more TB(s). The number of TBs scheduled by DCI may be determined by the number of multiple input multiple output (MIMO) transport layers. For example, the number of TBs may be one when the number of transport layers is equal to or less than the reference value, and the number of TBs may be two when the number of transport layers exceeds the reference value. In an embodiment, for convenience of description, up to two TRPs and CORESETs used to transmit one DCI may be considered. However, the proposed methods can be easily extended to the case where the number of TRPs and the number of CORESETs are 3 or more.

4 is a conceptual diagram illustrating a first embodiment of a PDCCH transmission method according to second and third scenarios.

Referring to FIG. 4 , the UE may receive a first PDCCH from a first TRP and may receive a second PDCCH from a second TRP. The first PDCCH may be transmitted through a first CORESET configured in the terminal (or search space sets corresponding to the first CORESET, PDCCH monitoring occasions, etc.). The second PDCCH may be transmitted through a second CORESET configured in the terminal (or search space sets corresponding to the second CORESET, PDCCH monitoring occasions, etc.). According to the second scenario, the first and second PDCCHs may include the same DCI (or the same DCI payload). The UE may receive the first PDCCH based on the QCL assumption for the first CORESET, and may receive the second PDCCH based on the QCL assumption for the second CORESET. The QCL may include a spatial QCL (eg, QCL type D).

When the first and second CORESETs are disposed in different time resources, the UE may apply receive beamforming for each CORESET regardless of whether the spatial QCL assumption of the first and second CORESETs is the same, and to each CORESET PDCCH monitoring may be performed. On the other hand, when the first and second CORESETs overlap in time and have different spatial QCL assumptions, a certain terminal according to the RF (radio frequency) capability of the terminal applies a priority between the CORESETs by applying one Only CORESET can be monitored.

The UE may successfully receive both the first and second PDCCHs according to the PDCCH blind decoding result. In this case, the UE may perform a soft combining operation on a plurality of DCIs. Accordingly, the decoding performance of DCI may be improved. Alternatively, the UE may successfully receive only one PDCCH among the first and second PDCCHs. When “the first PDCCH is successfully received” or “the second PDCCH is successfully received”, the UE can successfully acquire DCI from the received PDCCH, and the PDCCH decoding performance is improved by the beam diversity effect can be

According to the third scenario, DCI may be transmitted over multiple (eg, two) CORESETs and multiple (eg, two) PDCCHs. Each of the plurality of TRPs may transmit DCI to the UE through different PDCCHs on independent resources (eg, different CORESETs, different search space sets, and different PDCCH candidates). DCIs (eg, DCI payloads) transmitted from TRPs may generally be different. Alternatively, DCIs (eg, DCI payloads) transmitted from TRPs may be the same. DCIs transmitted from TRPs may schedule the same downlink TB(s), the same uplink TB(s), or the same HARQ process. In the embodiment of FIG. 4 , according to the third scenario, DCIs transmitted through the first and second PDCCHs may generally be different from each other. DCIs transmitted through the first and second PDCCHs may include scheduling and resource allocation information for the same TB(s). In this case, strictly speaking, the first and second PDCCHs may be regarded as different PDCCHs, and it may be difficult to see that the transmission reliability of the PDCCH itself is improved. However, transmission reliability of at least TB(s) or data channels (eg, PDSCH, PUSCH) scheduled from PDCCHs may be improved.

Hereinafter, embodiments of a PDCCH transmission method (eg, a PDCCH repeated transmission method) according to the second scenario will be described. However, some embodiments may correspond to a “third scenario” or a “combined scenario of the second and third scenarios”. In the embodiments, the scheduling of the downlink TB will be mainly considered, but the embodiments may be implemented in the same or similar manner for the scheduling of the uplink TB.

[Data channel scheduling method]

The PDSCH may be mapped to temporally consecutive symbol(s). Accordingly, the time domain resource allocation information of the PDSCH may include information about the start symbol (or index of the start symbol) of the PDSCH and the duration of the PDSCH (eg, the number of symbol(s) constituting the PDSCH). Information on the PDSCH start symbol (hereinafter referred to as “S”) and information on the length of the PDSCH (hereinafter referred to as “L”) may be expressed as a start and length indicator value (SLIV). The base station may instruct or set the SLIV to the terminal. One SLIV value may correspond to one (S, L) pair. Alternatively, each of S and L may be defined as a separate parameter, and the base station may indicate or set each of S and L to the terminal.

A method for the UE to interpret the PDSCH start symbol (eg, the value of S) may include at least the following two methods. The first method may be a method in which the value of S is interpreted as an index of a PDSCH start symbol in a slot (eg, a value from 0 to 13 in the case of a general CP in an NR communication system). In other words, the S value may be regarded as a symbol distance or a symbol offset between a PDSCH start symbol and a slot boundary (eg, a first symbol of a slot to which a PDSCH is allocated or a start time of the first symbol). For example, when S=3 is indicated to the UE, the UE may regard the start symbol of the PDSCH as the fourth symbol of the corresponding slot (eg, a symbol having an index of 3). The second method may be a method in which the value of S is interpreted as a symbol distance or a symbol offset between the PDSCH start symbol and one symbol through which the PDCCH is transmitted (eg, the first symbol of the PDCCH). The PDCCH may be a PDCCH scheduling a PDSCH. For example, when S=3 is indicated to the UE, the UE may consider that the start symbol of the PDSCH is later than the PDCCH start symbol by 3 symbols. That is, when the PDCCH start symbol is the X-th symbol of the slot, the UE may consider that the PDSCH is mapped from the (X+3)-th symbol of the slot.

Meanwhile, in the second and third scenarios, a plurality of PDCCHs may schedule the same PDSCH. This may be referred to as (Method 100). Alternatively, a plurality of PDCCHs may generally schedule different PDSCHs. This may be referred to as (Method 110). (Method 100) may be implemented by the first method described above. (Method 110) may be implemented by the first method or the second method described above.

FIG. 5A is a conceptual diagram illustrating a first embodiment of a PDSCH scheduling method using multiple PDCCHs, and FIG. 5B is a conceptual diagram illustrating a second embodiment of a PDSCH scheduling method using multiple PDCCHs. The embodiments shown in FIGS. 5A and 5B may be implemented by (Method 100).

5A and 5B , a plurality of PDCCHs (eg, first and second PDCCHs) may schedule the same PDSCH (eg, first PDSCH). In the embodiment shown in FIG. 5B , a PDSCH (eg, first PDSCH) scheduled from a plurality of PDCCHs (eg, first and second PDCCHs) may be repeatedly transmitted. Each PDSCH repeatedly transmitted may be referred to as a PDSCH instance (eg, first and second PDSCH instances).

In the embodiments of FIGS. 5A and 5B , the PDSCH start symbol may be indicated based on a slot boundary (eg, a start time or a start symbol of a slot to which the PDSCH is allocated) by the first method. The UE may obtain S through DCI, may consider that the value of S is a symbol index within a slot, and determine a corresponding symbol corresponding to S as a PDSCH start symbol. Therefore, when a plurality of PDCCHs are transmitted in the same slot, the same PDSCH may be scheduled by the plurality of PDCCHs regardless of the location of a time resource in which the plurality of PDCCHs are transmitted. When a plurality of PDCCHs are transmitted in different slots, each PDCCH may schedule different PDSCHs. Different PDSCHs may be allocated to different slots. This may correspond to (Method 110). Alternatively, when a plurality of PDCCHs are transmitted in different slots, the plurality of PDCCHs may schedule the same PDSCH (or the same PDSCHs, the same PDSCH instance(s) constituting repeated transmission). In this case, the time resource of the PDSCH (eg, a slot in which the PDSCH is transmitted, a start symbol of the PDSCH, etc.) is a resource in which one PDCCH among a plurality of PDCCHs is transmitted (eg, a search space in which one PDCCH is transmitted). The set, CORESET, or PDCCH monitoring occasion may be determined based on the relative distance from the allocated slot and/or symbol). One PDCCH may be a PDCCH transmitted the latest among a plurality of PDCCHs (eg, a PDCCH transmitted in the latest slot or a PDCCH having the latest end symbol).

Alternatively, in the embodiments of FIGS. 5A and 5B , the PDSCH start symbol may be interpreted as a relative symbol distance from a symbol through which the PDCCH is transmitted (eg, the first symbol of the PDCCH) by the second method. At this time, when a plurality of PDCCHs are transmitted in different symbol(s) (eg, when the start symbols of the plurality of PDCCHs are different), the time resource of the PDSCH (eg, the start symbol of the PDSCH, the PDSCH is The transmitted slot, etc.) may be determined based on a relative distance from a symbol in which one PDCCH among a plurality of PDCCHs is transmitted (eg, a start symbol of one PDCCH). One PDCCH may be a PDCCH having a later (or earlier) end symbol among a plurality of PDCCHs. Alternatively, one PDCCH may be a PDCCH having an earlier (or later) start symbol among a plurality of PDCCHs. Further details on this will be described later.

6A is a conceptual diagram illustrating a third embodiment of a PDSCH scheduling method using multiple PDCCHs, and FIG. 6B is a conceptual diagram illustrating a fourth embodiment of a PDSCH scheduling method using multiple PDCCHs. The embodiments of FIGS. 6A and 6B may be implemented by (Method 110).

6A and 6B , each of a plurality of PDCCHs may schedule a different PDSCH. For example, the first PDCCH may schedule the first PDSCH, and the second PDCCH may schedule the second PDSCH. In the embodiment of FIG. 6B , each PDSCH (eg, first and second PDSCHs) may be repeatedly transmitted.

In the embodiments of FIGS. 6A and 6B , the PDSCH start symbol may be indicated based on one symbol through which the PDCCH is transmitted (eg, the first symbol of the PDCCH) by the second method. The PDCCH may be a PDCCH scheduling a PDSCH (eg, a scheduling PDCCH, a scheduling DCI). The UE may acquire S through DCI, and may find out a PDSCH start symbol corresponding to each PDCCH by applying S to each PDCCH. For example, the UE may obtain information indicating S=2 through DCI received from the first and second PDCCHs. Based on S=2, the UE may consider that each of the first and second PDSCHs is mapped from a symbol that is two symbols later from the start symbol of the first and second PDCCH. In this case, when the start symbol of the first PDCCH is different from the start symbol of the second PDCCH, the first and second PDSCHs may be transmitted on different time resources. That is, the first and second PDSCHs may be different from each other. In this case, the first and second PDCCHs may be transmitted in the same slot or may be transmitted in different slots. On the other hand, "when the start symbol of the first PDCCH is the same as the start symbol of the second PDCCH" and "when the first and second PDCCHs are transmitted in the same slot", the first and second PDSCHs are "same time resource" or It can be transmitted on "same time resource and same frequency resource". That is, the first and second PDSCHs may be the same. In summary, by (Method 110), the base station can schedule the same PDSCH or different PDSCHs through the plurality of PDCCHs by appropriately determining the positions of the start symbols of the plurality of PDCCHs.

Alternatively, in the embodiments of FIGS. 6A and 6B , the PDSCH start symbol may be indicated by the first method. For example, a plurality of PDCCHs (eg, first and second PDCCHs) may be transmitted in different slots. In this case, the first and second PDCCHs may include the same DCI (or DCI payload), and the slot offset (eg, scheduling) of the first and second PDSCHs indicated from the first and second PDCCHs. The slot distance between the slot in which the PDCCH is transmitted and the slot in which the PDSCH is transmitted) may be the same. Accordingly, the first and second PDSCHs may be transmitted in different slots.

In the above-described embodiments, the first and second PDCCHs (or first and second PDCCH candidates, first and second search space sets corresponding to the first and second PDCCHs) are different CORESETs may belong to For example, when (Method 110) is used, repeatedly transmitted PDCCHs may belong to different CORESETs, and different CORESETs may belong to different CORESET pools. That is, different CORESETs may be included in CORESET pools having different CORESET pool IDs, respectively. Each CORESET pool may correspond to each TRP (or each cell, each radio unit (RU), etc.) state can be assumed. According to the above-described method, the PDCCH and PDSCH may be transmitted from a plurality of TRPs (or a plurality of cells, a plurality of RUs, etc.), and the PDCCH and PDSCH reception performance of the UE may be improved.

In embodiments, cross-carrier scheduling may be used. That is, a plurality of serving cells may be configured in the terminal, and the cell in which the PDCCHs are transmitted (ie, the scheduling cell) may be different from the cell in which the PDSCH scheduled by the PDCCHs is transmitted (ie, the scheduled cell). . In this case, a plurality of PDCCHs transmitted from a plurality of TRPs may be transmitted in the same cell. Alternatively, each of a plurality of PDCCHs transmitted from a plurality of TRPs may be transmitted in different cells. For example, a plurality of scheduling cells (eg, PCell/PSCell and SCell) may correspond to one scheduled cell (eg, PCell/PSCell), and a plurality of PDCCHs from each of the plurality of scheduling cells can be transmitted.

[PDCCH reception procedure]

The UE may receive the PDCCH according to a procedure to be described below. The PDCCH reception procedure of the UE may include first, second, and third steps. The PDCCH reception procedure of the UE may correspond to the PDCCH transmission procedure of the base station. Up to two PDCCHs and DCIs can be considered for one scheduling.

The first step of the PDCCH reception procedure may be a step in which the UE performs a PDCCH decoding operation. The UE may determine PDCCH candidate(s) to be monitored based on configuration information such as CORESET and search space set received from the base station and/or a predefined PDCCH mapping rule, and blindly decode the PDCCH candidate(s). can do.

The second step may be a step in which the UE checks whether the PDCCH is repeatedly transmitted. The UE may check whether any two DCIs successfully received are DCIs that are repeatedly transmitted according to a predetermined determination criterion. This operation may be performed in the second scenario. Alternatively, the UE may check whether any two DCIs successfully received are DCIs scheduling the same TB(s) according to a predetermined determination criterion. This operation may be performed in the third scenario. For example, "If any two DCIs successfully received are transmitted in the same slot", "If the CRCs of any two DCIs successfully received are scrambled with the same RNTI", and "If any two successfully received DCIs are transmitted in the same slot", If one or more conditions are simultaneously satisfied among the DCIs transmitted in the same PDCCH monitoring resource pool, the UE indicates “DCIs in which two DCIs are repeatedly transmitted” or “two DCIs are the same TB(s)” DCIs scheduling . The above-described conditions may correspond to a sufficient condition for determining that two DCIs are DCIs repeatedly transmitted or DCIs scheduling the same TB(s). Together with or separately from the above conditions, when any two DCIs that have been successfully received are received in each of the PDCCH candidates connected to each other (or in the search space sets connected to each other), the UE determines that the DCIs in which the two DCIs are repeatedly transmitted are or DCIs scheduling the same TB(s). Specific details on the connection of the PDCCH monitoring resource pool and the PDCCH candidates will be described later.

Together with or separately from the above operation, if any two DCIs successfully received have the same payload, the UE may determine that the two DCIs are DCIs that are repeatedly transmitted. Alternatively, when the payload of at least a part of any two successfully received DCIs is the same, the UE may determine that the two DCIs are DCIs scheduling the same TB(s). At least a portion of the payload includes field(s) (eg, HARQ process ID, time domain resource allocation, frequency domain resource allocation, number of TBs, MCS, redundancy (RV)) used for PDSCH reception and/or HARQ operation of the UE. version), new data indicator (NDI), TCI, downlink assignment index (DAI), DM-RS related field, CBG (code block group) related field, etc.). Alternatively, the terminal may obtain information indicating whether any two DCIs successfully received are DCIs repeatedly transmitted or DCIs scheduling the same TB(s) from the base station through an explicit method. For example, the UE may determine whether two DCIs are repeatedly transmitted or the same TB(s) are scheduled based on a specific field value of any two DCIs successfully received. A specific field is a field indicating whether DCI is repeatedly transmitted, a field indicating the number of DCI(s) that are repeatedly transmitted or scheduling the same TB(s), a DCI transmission counter field (eg, transmitted DCI is field indicating the number of copies of repeated transmission), and the like.

The third step may be a step in which the terminal processes DCI. In the second step, if it is determined that any two DCIs are DCIs repeatedly transmitted or DCIs scheduling the same TB(s), the UE uses only one DCI among the two DCIs to receive the PDSCH and/or A HARQ operation may be performed. One DCI may be arbitrarily determined by the UE. Alternatively, one DCI may be determined according to a predetermined rule. For example, the UE may select one DCI based on a time point at which two DCIs are received, a CORESET index, a search space set index, a search space set type, etc. A corresponding HARQ-ACK (acknowledgement) transmission operation may be performed. The UE may ignore another unselected DCI or omit processing of at least some payloads. Alternatively, the UE may use both DCIs to receive the PDSCH.

Meanwhile, DCIs may include fields (eg, PUCCH power control, PUCCH resource indication, SRS request, carrier indicator field (CIF), bandwidth part indicator, etc.) independent of the PDSCH reception operation and HARQ operation of the UE. In some cases (eg, the third scenario), fields (eg, field values, field sizes, etc.) of DCIs received through a plurality of PDCCHs may be different from each other. In this case, the UE may perform the corresponding operation by using all corresponding field values of the two DCIs. For example, the UE may perform all PUCCH power control operations corresponding to each of the two DCIs. Alternatively, the UE may perform the corresponding operation using a corresponding field value of one of the two DCIs. For example, the UE may determine the PUCCH transmission resource based on the PUCCH resource indication information of one DCI. As another example, the UE may transmit SRS based on SRS request information of one DCI. However, according to the above method, it may be difficult for the base station to know which PDCCH(s) the terminal has successfully received. Therefore, it may be difficult for the base station to predict the operation of the terminal according to DCI. In order to solve the above-described problem, the base station may determine the field(s) irrelevant to the PDSCH reception operation and the HARQ operation of the terminal as the same value for a plurality of DCIs, and transmit DCIs including the corresponding value. . That is, the UE can expect that field(s) of a plurality of DCIs independent of the PDSCH reception operation and the HARQ operation have the same value. Even if the UE receives both DCIs, the UE may perform an operation on the field only once by using only one DCI.

Among the steps of the above-described PDCCH reception procedure, some steps may be performed in a modified form or may be omitted. In addition, the PDCCH reception procedure may further include other steps in addition to the above-described steps.

The PDCCH monitoring resource pool may mean a set of resource regions and/or PDCCH candidate(s) in which the UE can expect to receive repeatedly transmitted PDCCHs. For example, the UE may check whether repeated transmission or scheduling of the same TB(s) for a plurality of (eg, two) PDCCHs or DCIs received within the same PDCCH monitoring resource pool.

The PDCCH monitoring resource pool includes one or more CORESET(s) (or PDCCH candidate(s) belonging to one or more CORESET(s)), one or more search space set(s) (or one or more search space set(s) belonging to PDCCH candidate(s)) and the like. For example, the UE may receive information instructing to set a specific CORESET(s) (or PDCCH candidate(s) belonging to a specific CORESET(s)) to the PDCCH monitoring resource pool from the base station. Alternatively, the terminal may receive information instructing to set a specific search space set(s) (or PDCCH candidate(s) belonging to a specific search space set(s)) as a PDCCH monitoring resource pool from the base station. The above-described setting operation (eg, setting operation of the PDCCH monitoring resource pool) may be performed by the RRC signaling procedure. Specific CORESET(s) may include CORESET #0. A specific search space set may include only the USS set. That is, multiple TRP-based PDCCH transmission may be performed only for DCI transmission for scheduling unicast and/or groupcast transmission. Alternatively, the specific search space set may include both the USS set and the CSS set without distinction. The specific search space set is a search space set configured to monitor a specific DCI format (eg, DCI formats 1_1, 1_2) and/or a specific RNTI (eg, C-RNTI, MCS-C-RNTI, CS-RNTI). may include. In this case, a plurality of search space sets or a plurality of CORESETs may be configured as a PDCCH monitoring resource pool, and a plurality of search space sets or a plurality of CORESETs may be connected to (or combined with) each other. In addition, a plurality of PDCCH candidates each belonging to a plurality of search space sets or a plurality of CORESETs may be connected to (or combined with) each other. The UE may monitor PDCCHs repeatedly transmitted on search space sets or CORESETs connected to each other. Details regarding the connection of PDCCH candidates will be described later.

Alternatively, the PDCCH monitoring resource pool may be a predefined resource set or a set of PDCCH candidate(s). For example, the PDCCH monitoring resource pool may include all CORESET(s) (or PDCCH candidate(s) belonging thereto) configured in the UE. Alternatively, the PDCCH monitoring resource pool may include the remaining CORESET(s) except for a specific CORESET (eg, CORESET #0) among the CORESET(s) configured in the terminal. Alternatively, the PDCCH monitoring resource pool may include all USS set(s) belonging to CORESET(s).

In some embodiments, each PDCCH monitoring resource pool may include M PDCCH candidates. Here, M may mean the maximum number of repeated transmissions of the PDCCH. M may be a natural number. For example, when M=2, the UE may perform blind decoding on each PDCCH candidate pair. When both PDCCHs are successfully received, the UE may consider that the two PDCCHs are repeatedly transmitted or are PDCCHs scheduling the same TB(s), and may perform a PDCCH reception procedure. According to this, the UE can perform a soft combining operation on repetitively transmitted DCIs with low complexity.

Together with or separately from the above-described operation, the PDCCH monitoring resource pool may occupy a predetermined time interval. Alternatively, the PDCCH monitoring resource pool may belong to a predetermined time interval. For example, the UE may check whether repeated transmission or scheduling of the same TB(s) for a plurality of (eg, two) PDCCHs or DCIs received within a predetermined time interval. A predetermined time period may be referred to as a PDCCH monitoring window. The PDCCH monitoring window may be configured in units of time of the above-described frame structure. For example, the PDCCH monitoring window may be configured based on one or a combination of two or more of one or more slot(s), one or more subslot(s), and one or more monitoring span(s). Here, the span may be composed of consecutive symbol(s), and 0, 1, or a plurality of span(s) may be arranged in one slot. For example, the PDCCH monitoring window may be one slot. That is, the PDCCH monitoring resource pool may occupy one slot. In this case, the UE may check whether the PDCCH is repeatedly transmitted by the method described above in each slot, and may perform a PDCCH reception procedure based on the checked result.

Alternatively, the PDCCH monitoring window (or PDCCH monitoring resource pool) may be determined based on the transmission timing of a specific signal. For example, the PDCCH monitoring window may be determined as a predetermined time interval starting from a point in time at which a DCI is received (ie, one symbol of the PDCCH (eg, the first symbol, the last symbol)). Together with or separately from the above-described operation, the PDCCH monitoring window may be a predetermined time interval ahead of the HARQ feedback transmission time (ie, one symbol of PUCCH or PUSCH (eg, the first symbol)). A given time interval may have a length based on one or a combination of two or more of contiguous symbol(s), slot(s), subslot(s), and monitoring span(s). In this case, the PDCCH monitoring window may be applied to each transmission serving as a reference time. For example, the UE may set a PDCCH monitoring window for each of the successfully received DCIs, and may check whether a DCI repeatedly transmitted for each of the successfully received DCIs is received within the PDCCH monitoring window.

[Connection of search space sets]

According to the above-described method, in the case of repeated multi-TRP-based PDDCH transmission, PDCCH candidates in which PDCCHs constituting repetitive transmission are transmitted may be associated (or linked). In addition, search space sets corresponding to PDCCH candidates may be combined (or concatenated) with each other. This operation will be described in the embodiments.

7 is a conceptual diagram illustrating a first embodiment of a method for concatenating a PDCCH search space set for repeated PDCCH transmission.

Referring to FIG. 7 , the terminal may receive configuration information of first and second search space sets (eg, first and second SS sets) from the base station. A first search space (eg, a first set of search spaces) may be interconnected to a first CORESET, and a second search space (eg, a second set of search spaces) may be interconnected to a second CORESET. The TCI state and/or QCL of the first and second CORESETs may be individually set or determined. For example, PDCCH transmission in the first and second CORESETs may be performed from different TRPs, and the TCI state and/or QCL source of the first and second CORESETs may be different from each other. Alternatively, the first CORESET and the second CORESET may be the same. For example, the first CORESET and the second CORESET may have the same CORESET ID. In this case, the repeatedly transmitted PDCCHs may be monitored or received based on the same TCI state and/or QCL source.

In this case, the first and second search space sets may be connected to each other. In search space sets connected to each other, the PDCCH may be repeatedly transmitted. For example, for scheduling a PDSCH or a PUSCH, a PDCCH may be repeatedly transmitted, and the repeatedly transmitted PDCCH may include first and second PDCCHs. In this case, the first PDCCH may be transmitted in the first search space set, and the second PDCCH may be transmitted in the second search space set. In addition, the PDCCH candidate(s) belonging to the first search space set and the PDCCH candidate(s) belonging to the second search space set may be connected to each other. In the embodiment of FIG. 7 , PDCCH candidate #0 (or PDCCH candidate having index 0) belonging to the first search space set is PDCCH candidate #0 (or PDCCH candidate having index 0) belonging to the second search space set. and PDCCH candidate #1 (or PDCCH candidate having an index of 1) belonging to the first search space set is connected to PDCCH candidate #1 (or PDCCH candidate having an index of 1) belonging to the second search space set. can In PDCCH candidates connected to each other, the PDCCH may be repeatedly transmitted. For example, the first PDCCH may be transmitted on PDCCH candidate #0 of the first search space set, and the second PDCCH may be transmitted on PDCCH candidate #0 of the second search space set. Alternatively, the first PDCCH may be transmitted in PDCCH candidate #1 of the first search space set, and the second PDCCH may be transmitted in PDCCH candidate #1 of the second search space set. The UE may receive information about the connection (or mutual combination) of search space sets or PDCCH candidates through signaling (eg, RRC signaling, MAC CE, and/or DCI signaling) from the base station.

A connection relationship of PDCCH candidates on the concatenated search space sets may be determined based on a PDCCH candidate index. For example, as in the above-described embodiment, PDCCH candidates having the same index between the first and second search space sets may be connected to each other. In addition, the connection relationship of PDCCH candidates between the connected search space sets may be determined based on an aggregation level. For example, PDCCH candidates having the same aggregation level between the first and second search space sets may be connected to each other. Alternatively, PDCCH candidates having the same aggregation level and the same PDCCH candidate index between the first and second search space sets may be connected to each other. When a PDCCH candidate having a specific aggregation level and/or a specific PDCCH candidate index exists in only one search space set among the first and second search space sets connected to each other, the corresponding PDCCH candidate may not be connected to another PDCCH candidate, , the corresponding PDCCH candidate may not be used for repeated PDCCH transmission.

[Settings of linked navigation space sets]

The interconnected search space sets (or monitoring occasions corresponding to the interconnected search space sets) may be set to have the same monitoring cycle. Also, the search space sets connected to each other (or monitoring occasions corresponding to the search space sets connected to each other) may be arranged in the same slot. For example, the slot offsets of the search space sets may be set to the same value. Alternatively, as a method for increasing scheduling freedom, it may be allowed to arrange the search space sets connected to each other in different slots. Considering the number of TRPs participating in multi-TRP transmission, a maximum of X search space sets may be connected to each other. X may be a natural number greater than one. For example, X=2. Also, search space sets connected to each other may be set to the same search space set type. For example, the search space sets connected to each other may be USS sets. For another example, the search space sets connected to each other may be CSS sets.

The same aggregation level(s) may be configured in search space sets connected to each other, and the same number of PDCCH candidate(s) may be configured for each aggregation level. In this case, the search space sets may include the same number of PDCCH candidate(s), and the PDCCH candidates may have a one-to-one correspondence between the search space sets.

8A is a conceptual diagram illustrating a second embodiment of a method of concatenating a PDCCH search space set for repeated PDCCH transmission.

Referring to FIG. 8A , the first and second search space sets may be connected to each other for repeated PDCCH transmission, and may be configured with the same aggregation level(s) and the same number of PDCCH candidates. For example, each of the first and second search space sets includes PDCCH candidates #0 and #1 (ie, PDCCH candidates having indices 0 and 1) for aggregation level 1 and PDCCH candidates #0 to #0 through aggregation level 2, respectively. #3 (ie, PDCCH candidates having indices 0 to 3) may be included. The PDCCH candidate of the first search space set and the PDCCH candidate of the second search space set may be connected by the above-described method. For example, PDCCH candidates having the same aggregation level and the same PDCCH candidate index (or number) between the first and second search space sets may be connected to each other.

Alternatively, the aggregation level(s) set for each search space set and/or the number of PDCCH candidates for each aggregation level may not necessarily coincide with each other. For example, some PDCCH candidate(s) in a certain search space set may be used for repeated PDCCH transmission in connection with PDCCH candidate(s) of another search space set, and some other PDCCH candidate(s) may be used in another search space set It can be used for single PDCCH transmission without connection with the PDCCH candidate(s) of The base station may perform both repeated PDCCH transmission and single PDCCH transmission using one search space set. That is, dynamic switching may be performed between repeated PDCCH transmission and single PDCCH transmission.

8B is a conceptual diagram illustrating a third embodiment of a method of concatenating a PDCCH search space set for repeated PDCCH transmission.

Referring to FIG. 8B , the first and second search space sets may be connected to each other for repeated PDCCH transmission, and may consist of different numbers of PDCCH candidates. For example, the first search space set may include two PDCCH candidates for aggregation level 1 and two PDCCH candidates for aggregation level 2. That is, the first search space set may include four PDCCH candidates. The second search space set may include one PDCCH candidate for aggregation level 1 and four PDCCH candidates for aggregation level 2. That is, the second search space set may include 5 PDCCH candidates. The PDCCH candidate of the first search space set and the PDCCH candidate of the second search space set may be connected by the above-described method. For example, PDCCH candidates having the same aggregation level and the same PDCCH candidate index (or number) between the first and second search space sets may be connected to each other. According to the above rule, some PDCCH candidates (eg, PDCCH candidate #1 for aggregation level 1 in the first search space set (or PDCCH candidates having an index of 1)) and for aggregation level 2 in the second search space set PDCCH candidates #2 and #3 (or PDCCH candidates having indices 2 and 3) may not be connected. Unconnected PDCCH candidates may be used for single PDCCH transmission.

PDCCH mapping rule of "connected search space sets" and/or "CORESETs corresponding to interconnected search space sets" (eg, mapping between CCE and REG, REG bundling, whether interleaving is applied, DM-RS setting ), beam-related operations (eg, TCI state), whether cross-carrier scheduling is applied, etc. may be set independently of each other (eg, the same as or different from each other). On the other hand, a specific setting parameter may be identically set between "search space sets connected to each other" and/or "CORESETs corresponding to search space sets connected to each other". For example, whether DCI scheduled from CORESET includes TCI state information (or QCL information, beam indication information, etc.) of PDSCH is determined by CORESETs (eg, first and The same can be set for the second CORESETs). The above-described configuration may be performed by RRC signaling (eg, RRC parameter 'TCIPresenceInDCI'). Accordingly, the UE can expect that the TCI state information of the PDSCH is included in all of the repeatedly transmitted DCIs. Alternatively, the UE may expect that the TCI status information of the PDSCH is not included in all of the repeatedly transmitted DCIs. As a result, the payload (eg, payload of DCI formats transmitted from search space sets (eg, first and second search space sets) connected to each other corresponding to the first and second CORESETs) A set of constituting fields, a size of each field, an interpretation method of each field, etc.) may match, and the UE may improve PDCCH decoding performance by performing a soft combining operation on a plurality of received DCIs.

Meanwhile, a CORESET mutually combined with a search space set for repeated PDCCH transmission may be mutually combined with another search space set (eg, a search space set not used for repeated PDCCH transmission). Therefore, in some cases, it may be difficult to equally set whether the DCI includes PDSCH TCI status information between the first CORESET and the second CORESET. In this case, when the DCI is set to include the TCI status information of the PDSCH for at least one CORESET, the UE is transmitted in all connected search space sets (eg, first and second search space sets) to DCI. It may be considered that the TCI state information of the PDSCH is included, and PDCCH and PDSCH reception operations may be performed based on the considered result. The DCIs may include TCI status information of the same PDSCH. Alternatively, when DCI is configured not to include TCI state information of PDSCH for at least one CORESET, the UE transmits in all connected search space sets (eg, first and second search space sets). It may be considered that the DCI does not include TCI state information of the PDSCH, and PDCCH and PDSCH reception operations may be performed based on the considered result. That is, even if it is configured to monitor a DCI that does not include the TCI state information of the PDSCH in a certain search space set (or CORESET corresponding to the search space set), the UE may use at least some DCIs of the corresponding search space set (for example, , DCI for repeated PDCCH transmission, and DCI transmitted in a connected PDCCH candidate) may be regarded as including TCI state information. Alternatively, even if monitoring of the DCI including the TCI state information of the PDSCH in a certain search space set (or CORESET corresponding to the search space set) is configured, the UE may use at least some DCI of the corresponding search space set (e.g., DCI for repeated PDCCH transmission and DCI transmitted from a connected PDCCH candidate) may be regarded as not including TCI state information. In this case, the PDSCH DM-RS may be considered to be QCL with the PDCCH DM-RS scheduling the PDSCH. Alternatively, the PDSCH DM-RS may be considered to be QCL with any downlink signal (eg, DM-RS of a certain CORESET, SS/PBCH block, CSI-RS, TRS, etc.) according to a predetermined rule.

[Monitoring of connected PDCCH candidates]

_{The maximum value (hereinafter, referred to as “N BD} ”) and processing of the number of times of PDCCH blind decoding that the UE can perform during each reference time (eg, each slot, each span, and each Z consecutive slots) The maximum value of the number of possible CCEs (hereinafter referred to as "N _CCEs ") may be set in the terminal from the base station. Alternatively, N _BD and N _CCE may be predefined in the technical standard. The terminal sets the search space set within the reference time "until the total number of PDCCH candidates does _{not exceed N BD} for each reference time described above" and/or "until the total number of _{CCEs does not exceed N CCE" (for example,} , PDCCH candidates belonging to the search space set) may be sequentially mapped. The UE may perform a blind decoding operation on a PDCCH candidate belonging to a mapped search space set, and may omit a blind decoding operation on a PDCCH candidate belonging to an unmapped search space set. In this case, the CSS set may be mapped preferentially over the USS set, and the terminal may not expect that the CSS set is not mapped. That is, all PDCCH candidates belonging to the CSS set may always be monitored by the UE. In addition, the search space set may be sequentially mapped based on the ID of the search space set (eg, in the order of the lowest ID of the search space set). For example, the mapping operation based on the ID of the search space set may be performed on the USS set(s) after all CSS set(s) are mapped. The above-described method may be performed for each serving cell. When cross-carrier scheduling is used, the above-described method may be applied to scheduling cell(s) (eg, cell(s) to which scheduling DCI is transmitted).

In this case, the first and second search space sets connected to each other may or may not be all mapped. That is, the terminal may not expect that only one search space set among the first search space set and the second search space set is mapped. In this case, the terminal may monitor both the first search space set and the second search space set, or may not monitor both. That is, the UE may monitor both the first PDCCH candidate and the second PDCCH candidate connected to each other between the first search space set and the second search space set, or may not monitor both. This may be referred to as (method 120). Alternatively, "an operation in which both the interconnected first search space set and the second search space set are mapped", "an operation in which neither the interconnected first search space set and the second search space set are mapped"; An operation in which only one search space set from among the first search space set and the second search space set is mapped" may be permitted. When only one search space set is mapped, the terminal may monitor only one search space set among the first search space set and the second search space set connected to each other. That is, the UE may monitor only one PDCCH candidate among the first PDCCH candidate and the second PDCCH candidate connected to each other between the first search space set and the second search space set. This may be referred to as (Method 130). In this case, the first and second search space sets may belong to the same reference time (eg, the same slot or the same span). Alternatively, the first and second search space sets may belong to different reference times (eg, different slots or different spans).

The number of blind decodings for two PDCCH candidates connected to each other belonging to the first and second search space sets may be counted a total of Y times. For example, Y=2 may be fixed. Alternatively, Y=3 may be fixed. The Y value can be defined in the technical standard. In addition, the Y value may be defined as the capability of the terminal. The terminal may report the Y value supported by the terminal to the base station, and the base station may set the Y value applied to counting the number of times of blind decoding to the terminal with reference to the Y value supported by the terminal. The method described above can be applied when (Method 120) is used. In addition, in the above-described method, even when only one PDCCH candidate among the two PDCCH candidates connected to each other is monitored, the number of blind decodings may be counted a total of Y times. Accordingly, the above-described method can be applied even when (method 130) is used.

Alternatively, blind decoding may be counted once for each of two PDCCH candidates connected to each other belonging to the first and second search space sets. Accordingly, when "only one PDCCH candidate among two PDCCH candidates is mapped" or "in case the terminal monitors only one PDCCH candidate among two PDCCH candidates", blind decoding may be counted once in total. In the case of "when all two PDCCH candidates are mapped" or "when the terminal monitors all two PDCCH candidates", blind decoding may be counted twice in total. Alternatively, when "only one candidate among two PDCCH candidates connected to each other is mapped" or "when a terminal monitors only one candidate among two PDCCH candidates connected to each other", blind decoding may be counted, respectively. In this case, blind decoding may be counted once. In the case of "when all two PDCCH candidates connected to each other are mapped" or "when the terminal monitors all two PDCCH candidates connected to each other", blind decoding may be counted Y times by the above-described method. Meanwhile, in addition to blind decoding for each PDCCH candidate, the UE may perform blind decoding once more by performing a soft combining operation of DCIs for two PDCCH candidates. In this case, among two PDCCH candidates connected to each other belonging to the first and second search space sets, blind decoding for the first PDCCH candidate may be counted once, and blind decoding for the second PDCCH candidate may be counted twice. can Here, the first and second PDCCH candidates (eg, a search space set to which each of the first and second PDCCH candidates belong, mapping resources of the first and second PDCCH candidates, etc.) may be determined through configuration from the base station. . Alternatively, the first and second PDCCH candidates (eg, a search space set to which each of the first and second PDCCH candidates belong, mapping resources of the first and second PDCCH candidates, etc.) may be determined by the blind decoding order of the UE. have. The above-described method can be applied when (Method 130) is used.

When _{only some of the PDCCH candidates connected to each other are mapped due to the N BD} constraint, the UE may still perform a PDCCH monitoring operation on some mapped PDCCH candidate(s). For example, when only one PDCCH candidate is mapped among two PDCCH candidates connected to each other, the UE may perform a blind decoding operation on one mapped PDCCH candidate. In this case, the PDCCH candidate may still be considered as a PDCCH candidate for repeated PDCCH transmission. That is, the PDCCH repeated transmission method described in the embodiments (eg, PDCCH reception operation, data channel transmission/reception operation, HARQ-ACK feedback operation, DCI format payload configuration, etc.) will be used for monitoring and reception of PDCCH candidates. can In addition, one PDCCH candidate (or a resource of a PDCCH candidate) among PDCCH candidates connected to each other for the above operation may be a reference PDCCH candidate (or a resource of a PDCCH candidate). In this case, the reference PDCCH candidate may be determined regardless of whether the above-described PDCCH candidate(s) are mapped. For example, a PDCCH candidate having a later end symbol (or an earlier start symbol) among the PDCCH candidates connected to each other may be considered as a reference PDCCH candidate, and a location of a time resource (eg, a start symbol) of the PDSCH, Whether to apply the default beam of the PDSCH, the HARQ-ACK codebook configuration, etc. may be determined by the reference PDCCH candidate or the resource of the reference PDCCH candidate. In this case, with respect to the PDCCH candidates connected to each other, a reference PDCCH candidate when all the connected PDCCH candidates are mapped may coincide with a reference PDCCH candidate when only some PDCCH candidates are mapped. In addition, the PDCCH candidate mapped by the above-described method may be set as a reference PDCCH candidate. Alternatively, a PDCCH candidate not mapped by the above-described method may be set as a reference PDCCH candidate.

Alternatively, in the above-described case, the PDCCH candidate may be regarded as a PDCCH candidate for single PDCCH transmission. The PDCCH repeated transmission method described in the embodiments (eg, PDCCH reception operation, data channel transmission/reception operation, HARQ-ACK feedback operation, DCI format payload configuration, etc.) may not be applied to the monitoring and reception operation of PDCCH candidates. can The location of the time resource (eg, start symbol) of the PDSCH, whether a default beam of the PDSCH is applied, the HARQ-ACK codebook configuration, etc. may be determined by the mapped PDCCH candidate or the mapped PDCCH candidate resource. Alternatively, the above-described reference PDCCH candidates may be determined according to whether PDCCH candidate(s) connected to each other are mapped. For example, a mapped PDCCH candidate among the PDCCH candidates connected to each other may be considered a reference PDCCH candidate, and an unmapped PDCCH candidate may not be considered a reference PDCCH candidate. For example, only the first PDCCH candidate among the first PDCCH candidates and the second PDCCH candidates connected to each other may be mapped. In this case, the mapped first PDCCH candidate may be regarded as a reference PDCCH candidate regardless of the above-described condition (eg, order of end symbols, etc.).

As another method, when only some PDCCH candidate(s) among PDCCH candidates connected to each other are mapped, the UE may omit a blind decoding operation for some mapped PDCCH candidate(s). In other words, when the blind decoding operation for some PDCCH candidate(s) is omitted from among the PDCCH candidates connected to each other by the counting rule for the number of times of PDCCH blind decoding, the UE may also omit the blind decoding operation for the remaining PDCCH candidate(s). have. In this case, even if the blind decoding operation of the PDCCH candidate(s) is omitted, the number of times of blind decoding for the PDCCH candidate(s) may be counted by the above-described method.

Meanwhile, the UE may omit monitoring of some PDCCH candidate(s) among PDCCH candidates connected to each other by other conditions in addition to the PDCCH blind decoding number counting rule. For example, "Some PDCCH candidate(s) among PDCCH candidates connected to each other When overlapping with a cell-specific reference signal (CRS), transmission resource of a specific uplink signal and channel, PRACH, SRS) and/or "some PDCCH candidate(s) among PDCCH candidates connected to each other are uplink symbols and/or In the case of overlapping with the flexible symbol", the UE may omit blind decoding for some PDCCH candidate(s). For another example, "resources (eg, a set of CCEs) of some PDCCH candidate(s) among PDCCH candidates connected to each other are different PDCCH candidates (eg, a third PDCCH candidate) resource (eg, CCE set) and if a predetermined condition is additionally satisfied", the UE may omit blind decoding for some PDCCH candidate(s). Predetermined conditions are "condition that some PDCCH candidate(s) are included in the USS set and the third PDCCH candidate is included in the CSS set", "Some PDCCH candidate(s) and the same DCI format in the third PDCCH candidate (for example, , fallback DCI format, DCI format 0_0, 1_0) monitored condition”, “Condition that some PDCCH candidate(s) and DCI formats monitored by the third PDCCH candidate have the same size”, “Some PDCCH candidate(s) and the second A condition in which the same scrambling is applied to 3 PDCCH candidates" and "some PDCCH candidate(s) and RNTIs in which CRCs of DCI formats monitored in the third PDCCH candidate are the same (eg, C-RNTI, CS-RNTI, MCS- C-RNTI) scrambled conditions" may include at least one condition. For another example, "Some PDCCH candidates among the PDCCH candidates connected to each other overlap the type 1 CSS set, and different QCLs (e.g., QCL type D) are applied to the search space set to which some PDCCH candidates belong and the type 1 CSS set. case", the UE may omit blind decoding for some PDCCH candidates. A DCI format (eg, DCI format 1_0) having a CRC scrambled with RA-RNTI in the Type 1 CSS set may be transmitted. The UE may perform blind decoding on the remaining PDCCH candidate(s) except for some PDCCH candidate(s) among the PDCCH candidates connected to each other according to the above-described method, or may not perform blind decoding.

Meanwhile, the PDCCH monitoring operation of the UE may be dynamically changed. The base station may explicitly or implicitly indicate to the terminal a search space set group (SSSG) monitored by the terminal through DCI, and the terminal may monitor the SSSG indicated by the base station. At this time, if the SSSG indicated to the terminal is different from the SSSG currently monitored by the terminal, the terminal may perform the SSSG switching operation to the SSSG indicated by the current SSSG. The SSSG may include one or more search space set(s). Alternatively, the SSSG may not include a search space set. When monitoring the SSSG not including the search space set is indicated, the UE may omit the PDCCH monitoring operation in the monitoring period of the corresponding SSSG. Alternatively, the UE may monitor only the search space set(s) to be monitored (eg, CSS set, type 0/0A/1/2 CSS set, etc.) regardless of SSSG switching. An SSSG that does not include a search space set may be referred to as a null SSSG, an empty SSSG, a dormant SSSG, or the like. Together with or separately from the above-described operation, the base station may instruct the terminal to omit the PDCCH monitoring operation through DCI. As described above, this operation may be performed through a specific SSSG or a separate signaling operation. For example, the DCI may include information instructing the UE to omit the PDCCH operation for a predetermined period. The above-described PDCCH monitoring change operation may be applied in units of slots. Even if the above-described method is used, the UE may monitor the same search space set(s) within one slot.

The search space sets connected to each other and/or PDCCH candidates corresponding to the search space sets connected to each other may belong to different SSSGs. Alternatively, it may be indicated to omit the PDCCH monitoring operation for some of the PDCCH candidates corresponding to the interconnected search space sets and/or the interconnected search space sets. In this case, only the monitoring operation for the interconnected search space sets and/or some of the interconnected search space sets may be effective. This operation may occur when the search space sets connected to each other belong to different slots. In this case, the UE may perform the PDCCH monitoring operation according to the above-described method on the valid search space set(s) and/or the PDCCH candidate(s) corresponding to the valid search space set(s). Alternatively, by the above-described method, the UE may omit the PDCCH monitoring operation even for the valid search space set(s) and/or the PDCCH candidate(s) corresponding to the valid search space set(s).

Meanwhile, the PDSCH may be transmitted in a resource region other than a specific resource region. In the nominal resource region to which the PDSCH is allocated, the remaining resource regions except for a specific resource region may be considered as available resources for PDSCH transmission, and the PDSCH is rate matched according to the size of the remaining resource region. ), and the rate-matched PDSCH may be transmitted. "Operation of rate matching the PDSCH in a specific resource region or around a specific resource region" may refer to the above-described operation. A specific resource region may be referred to as a rate matching resource or a reserved resource for convenience. In order to prevent collision between the PDSCH and the PDCCH, the reserved resource may include CORESET. That is, all PDCCH monitoring occasions of all search space sets constituting a certain CORESET may be set as the reserved resource, and the UE may receive the corresponding PDSCH by rate matching the PDSCH on the reserved resource. In order to support this operation, the configuration information of the reserved resource may include the ID of the CORESET for rate matching the PDSCH.

If there are search space sets connected to each other among a plurality of CORESETs, repeatedly transmitted PDCCHs may be transmitted using the resources of the plurality of CORESETs. In this case, in order to prevent collision between the PDSCH and the PDCCH, the base station may set all of the plurality of CORESETs to the terminal as reserved resources. However, according to this method, all search space sets of a plurality of CORESETs (eg, all search space sets including search space set(s) not used for repeated PDCCH transmission) are set as reserved resources, Efficiency may decrease. Alternatively, the terminal may set at least one search space set (or CORESET corresponding to the at least one search space set) among the search space sets connected to each other as a reserved resource in the terminal. In this case, the UE may regard all search space sets connected to each other as reserved resources. The UE may receive the corresponding PDSCH by rate matching the PDSCH in all search space sets connected to each other (or time-frequency resources to which PDCCH monitoring occasions corresponding to all search space sets connected to each other are mapped). Alternatively, at least one PDCCH candidate (or a search space set corresponding to at least one PDCCH candidate, CORESET) among the PDCCH candidates connected to each other may be set as a reserved resource in the UE. In this case, the UE may regard all PDCCH candidates connected to each other as reserved resources. The UE may receive the corresponding PDSCH by performing PDSCH rate matching on the resources of all PDCCH candidates connected to each other. The method described above may be referred to as (method 140).

9 is a conceptual diagram illustrating a first embodiment of a PDSCH rate matching method.

Referring to FIG. 9 , the terminal may receive configuration information of the first and second CORESETs from the base station. That is, the first and second CORESETs may be set in the terminal. The first CORESET may include first to fourth search space sets, and the second CORESET may include first and second search space sets. In this case, the first search space set of the first CORESET and the first search space set of the second CORESET may be connected to each other. The first search space sets connected to each other between the first CORESET and the second CORESET may be used for repeated PDCCH transmission. The first CORESET may be set as a reserved resource in the terminal. In this case, the UE may rate-match the PDSCH in all search space sets (eg, time-frequency resources of all search space sets) included in the first CORESET. The terminal is a search space set of another CORESET (eg, a first search space set of a second CORESET (eg, a first search space set of For example, the time-frequency resource of the first search space set))) may be regarded as a reserved resource, and the PDSCH may be rate-matched in the reserved resource. Alternatively, the UE is a PDCCH candidate of another CORESET (eg, the PDCCH candidate of the first search space set) connected to the PDCCH candidate of the first CORESET (eg, the PDCCH candidate of the first search space set) by (method 140) (eg, the first search space of the second CORESET) PDCCH candidates of the set) may be considered as reserved resources. The above-described operation may be performed regardless of whether the second CORESET is set as a reserved resource. In an embodiment, even when the second CORESET is not set as a reserved resource, the UE may regard some search space sets of the second CORESET or some PDCCH candidates as reserved resources by the above-described method.

[Overlap of connected PDCCH candidates]

The interconnected search space sets (or CORESETs corresponding to the interconnected search space sets and PDCCH monitoring occasions corresponding to the interconnected search space sets) may be disposed in the same slot or different slots. In this case, the resources of the search space sets connected to each other may not overlap each other. For example, the search space sets connected to each other may be allocated to different symbol sets. Alternatively, the search space sets connected to each other may be allocated to different RE sets. Alternatively, the resources of the PDCCH candidates connected to each other may not overlap each other. PDCCH candidates connected to each other may be mapped to different CCE sets (or different REG sets, different RE sets). This may be referred to as (Method 150).

Meanwhile, at least two methods may be considered for mapping of the PDCCH DM-RS. As a first method, the PDCCH DM-RS may be mapped only to the REG (or PRB and/or symbol) through which the PDCCH is transmitted. For example, the PDCCH DM-RS may be mapped to all REGs through which the PDCCH is transmitted. In the first method, the PDCCH DM-RS may be referred to as a narrowband PDCCH DM-RS for convenience. As a second method, the PDCCH DM-RS may be mapped to all REGs constituting CORESET. Alternatively, the CORESET may be mapped to one or more frequency cluster(s), and the PDCCH DM-RS may be mapped to all REGs constituting the frequency cluster(s) in which the UE receives the PDCCH. A frequency cluster may mean a resource composed of consecutive PRBs and/or symbol(s) among PRBs constituting CORESET. In the second method, the PDCCH DM-RS may be referred to as a wideband PDCCH DM-RS for convenience. The UE may assume one PDCCH DM-RS from among the narrowband PDCCH DM-RS and the wideband PDCCH DM-RS, and may perform a PDCCH reception operation using the assumed PDCCH DM-RS. The above-mentioned assumption can be applied for each CORESET. The base station may configure the PDCCH DM-RS mapping type (eg, narrowband PDCCH DM-RS or wideband PDCCH DM-RS) for each CORESET in the terminal.

When the wideband PDCCH DM-RS is configured for the first search space set (or CORESET corresponding to the first search space set, PDCCH monitoring occasion) among the first and second search space sets connected to each other, the second search space The PDCCH candidates of the set may overlap with the PDCCH DM-RS of the first search space set. For example, even if the PDCCH candidate of the second search space set does not overlap with the PDCCH candidate of the first search space set connected thereto, the PDCCH candidate of the second search space set overlaps the PDCCH DM-RS of the first search space set. can be Along with this operation, a wideband PDCCH DM-RS may be configured for the second search space set (or CORESET corresponding to the second search space set, PDCCH monitoring occasion). In this case, the PDCCH candidate of the first search space set may overlap with the PDCCH DM-RS of the second search space set. When the above-described overlap occurs, reception performance of at least one of the PDCCH candidate and the PDCCH DM-RS may be deteriorated. Therefore, overlap between PDCCH candidate PDCCH DM-RS may be additionally considered in (Method 150). The PDCCH candidates connected to each other may not overlap each other, and at the same time, each of the PDCCH candidates connected to each other does not overlap with the PDCCH DM-RS (eg, wideband PDCCH DM-RS) of the relative search space set (or the relative PDCCH candidate). may not be The above-described method may be applied when the PDCCH DM-RS of at least one search space set (or CORESET corresponding to the at least one search space set) is configured as a wideband PDCCH DM-RS.

The wideband PDCCH DM-RS may be configured in all of the first and second search space sets connected to each other (or CORESETs corresponding to the first and second search space sets connected to each other). In this case, when the resource regions of the first and second search space sets connected to each other (or CORESETs corresponding to the first and second search space sets connected to each other) overlap, the first and second search space sets are formed. PDCCH DM-RSs transmitted for this purpose may overlap each other. According to this operation, the PDCCH reception performance may be deteriorated. To solve this problem, a frequency shift may be applied to the RE mapping of the wideband PDCCH DM-RS. For example, the positions of subcarriers to which the wideband PDCCH DM-RS are mapped in each search space set (or CORESET corresponding to each search space set) are determined in units of subcarriers (eg, L may be shifted by subcarrier(s). Different shift values (eg, L values) may be set in different CORESETs. According to this operation, wideband PDCCH DM-RSs in the first and second overlapping search space sets may not collide with each other. In a method different from the above-described method, the terminal sets the wideband PDCCH DM-RS to all of the first and second search space sets connected to each other (or CORESETs corresponding to the first and second search space sets connected to each other). You may not expect to be. As another method, the terminal may set a certain search space set (or in the search space set) among the first and second search space sets connected to each other (or CORESETs corresponding to the first and second search space sets connected to each other). It may not be expected that the wideband PDCCH DM-RS is configured in any corresponding CORESET).

[Data Channel Scheduling by Connected PDCCH Candidates]

The base station may indicate bandwidth partial switching through DCI repeatedly transmitted through PDCCH candidates connected to each other to the terminal. When partial bandwidth switching is indicated, the terminal may start transmitting/receiving operation in a new bandwidth portion from one slot (or the first symbol of the corresponding slot) after the instruction time of partial bandwidth switching. In this case, the above-described slot is a predetermined time (eg, the last symbol to which the corresponding PDCCH candidate is mapped or the slot to which the corresponding PDCCH candidate is mapped) to which one PDCCH candidate among the PDCCH candidates connected to each other is mapped. For example, it may be one slot after a predetermined number of symbols or a predetermined number of slots). In this case, PDCCH candidates (or search space sets corresponding to PDCCH candidates connected to each other) through which DCI(s) indicating bandwidth partial switching are transmitted are localized within the first Z symbols of the slot and may be mapped. . For example, the PDCCH candidates connected to each other (or search space sets corresponding to the PDCCH candidates connected to each other) may be localized and mapped within the first Z symbols of the same slot. For another example, the PDCCH candidates connected to each other (or search space sets corresponding to the PDCCH candidates connected to each other) may be localized within the first Z symbols in different slots and may be mapped. According to an embodiment, Z=3. The Z value may be defined in a technical standard and may be shared between the base station and the terminal. Alternatively, the PDCCH candidates connected to each other (or search space sets corresponding to the PDCCH candidates connected to each other) may be mapped to a resource region including other symbols in addition to the first Z symbols of the slot. The above-described mapping method may be applied regardless of whether the repetitively transmitted DCI indicates bandwidth partial switching. In addition, the above-described mapping method can be applied regardless of the subcarrier spacing of the bandwidth portion. For example, the above-described mapping method may be applied even when the subcarrier spacing of the bandwidth portion is not 15 kHz (eg, when the subcarrier spacing is 30, 60, 120, 240, 480, 960 kHz, etc.).

According to the above method, the UE can expect to receive one or two PDCCH(s) for scheduling of the same TB(s). The base station may arbitrarily determine the number (eg, one or two) of PDCCHs to be transmitted for each scheduling. A single PDCCH transmission method and a multiple PDCCH transmission method (eg, a PDCCH repeated transmission method) may be dynamically switched to each other. Accordingly, the scheduling freedom for the PDCCH of the base station may be increased. Alternatively, even if the above-described method is used, the terminal may receive configuration information of the number of PDCCHs that the terminal can expect to receive (eg, the maximum number of PDCCHs) from the base station for each scheduling. The setting of the maximum number of PDCCHs may be independently applied to downlink scheduling and uplink scheduling. For example, the terminal can expect to receive up to two PDCCHs for each downlink TB scheduling based on the configuration from the base station, and can expect to receive up to one PDCCH for each uplink TB scheduling. . The setting of the maximum number of PDCCHs may be applied for each PDCCH monitoring resource pool, CORSET(s), or search space set(s).

The above-described method may be applied when the PDSCH is scheduled by the PDSCH mapping type B. When the PDSCH is scheduled by the PDSCH mapping type B, the relative distance between the start symbol of the PDSCH and the symbol (eg, the start symbol) in which the PDCCH scheduling the PDSCH is transmitted may be limited. When (Method 100) is used, since the same PDSCH is scheduled by a plurality of PDCCHs, the resource allocation of the PDSCH may be performed so that the start symbol of the PDSCH does not precede the start symbol of any PDCCH scheduling the PDSCH. That is, when the first symbol of the earliest PDCCH among PDCCH(s) scheduling a certain PDSCH is later than the first symbol of the PDSCH, the UE may not receive the corresponding PDSCH. In addition, as described above, when (Method 100) is used, the start symbol (ie, S) of the PDSCH indicated by the DCI is a plurality of PDCCHs scheduling the PDSCH (or each other corresponding to the plurality of PDCCHs). One PDCCH (or a PDCCH candidate corresponding to one PDCCH) among the connected PDCCH candidates) may be interpreted as a symbol offset from a transmitted symbol.

One PDCCH (or a PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate having the lowest or highest ID of a corresponding search space set (or CORESET). Alternatively, one PDCCH (or a PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate having a later start symbol (or an end symbol) among PDCCH candidates connected to each other. Alternatively, one PDCCH (or PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate having an earlier start symbol (or an end symbol) among PDCCH candidates connected to each other. At this time, if the start symbol (or end symbol) of the PDCCH candidates connected to each other is the same, the UE may regard any PDCCH among the PDCCH candidates connected to each other as a reference PDCCH candidate, and based on the considered reference PDCCH candidate, the PDSCH It is possible to check the resource location and receive the PDSCH from the confirmed resource location. Alternatively, when the start symbols (or end symbols) of the PDCCH candidates connected to each other are the same, the UE may determine a reference PDCCH candidate based on an additional rule. For example, the additional rule may be a rule for selecting a PDCCH candidate having the lowest or highest ID of a search space set (or CORESET) corresponding to the PDCCH. Through the above-described method, even when PDSCH mapping type B is used, the same PDSCH (or the same PDSCHs, the same PDSCH instance(s) constituting repeated transmission) may be scheduled by a plurality of repeatedly transmitted PDCCHs. . When the above-described method is used, the symbol offset between the PDSCH start symbol and the PDCCH symbol (eg, the start symbol of the reference PDCCH candidate) may be an integer of 0 or more. That is, the symbol offset may not have a negative value.

As described above, (Method 100) can be applied even when a plurality of repeatedly transmitted PDCCHs are transmitted in different slots. In this case, in the slot in which the PDSCH is transmitted, one PDCCH (or a PDCCH candidate corresponding to one PDCCH) is transmitted among a plurality of PDCCHs for scheduling the PDSCH (or PDCCH candidates connected to each other corresponding to the plurality of PDCCHs). It may be determined based on the slot to be used. For example, slot offset information (eg, slot offset) may be configured in the UE of the PDSCH through scheduling DCI or RRC signaling. The slot offset may be interpreted as a slot distance between a slot in which a PDSCH is transmitted and a slot in which one PDCCH is transmitted.

One PDCCH (or a PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate having the lowest or highest ID of a search space set (or CORESET) corresponding to the corresponding PDCCH. Alternatively, one PDCCH (or a PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate transmitted later (eg, transmitted in a late transmission slot) among PDCCH candidates connected to each other. Alternatively, one PDCCH (or a PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate transmitted first (eg, transmitted in an early transmission slot) among PDCCH candidates connected to each other. Together with or separately from the above-described operation, the reference PDCCH candidate may be determined based on the positions of symbols in which the PDCCH candidates are transmitted. For example, one PDCCH (or a PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate located in a late start symbol (or a late end symbol) among PDCCH candidates connected to each other. Alternatively, one PDCCH (or a PDCCH candidate corresponding to one PDCCH) used as a reference view may be a PDCCH candidate located at an early start symbol (or an early end symbol) among PDCCH candidates connected to each other.

In the above-described case, the UE receives PDSCH time domain resource allocation information (eg, PDSCH start symbol, PDSCH slot offset) indicated by DCI (eg, DCI received through a PDCCH candidate not used as a reference view). etc.), the feedback timing of the HARQ-ACK corresponding to the PDSCH, the mapping order of the HARQ-ACK corresponding to the PDSCH in the HARQ-ACK codebook, etc., to a PDCCH candidate other than the resource of the PDCCH candidate from which the DCI was received (for example, , can be interpreted based on the resource (e.g., the slot and / or symbol in which the reference PDCCH candidate is transmitted) of the PDCCH candidate used as the reference view among the PDCCH candidate(s) connected to the PDCCH candidate in which the corresponding DCI is received. . The UE may identify a time resource to which the PDSCH is mapped based on the above-described interpretation, and may perform a PDSCH reception operation on the identified time resource.

(Method 100) may be applied when the PDSCH is scheduled by PDSCH mapping type A. In this case, all PDCCHs scheduling the PDSCH may be transmitted only in the first L symbol(s) of the slot. Here, L may be a natural number. If all PDCCH(s) scheduling the PDSCH are not received only within the first L symbol(s) of the slot, the UE may not receive the corresponding PDSCH. For example, L may be 3. As another example, L may be defined (or set) to a value greater than 3. Together with or separately from the above-described operation, the terminal may obtain the L value from the base station. The L value may be limitedly used when the above-described methods (eg, a multi-TRP-based PDCCH transmission method) are used. For example, the L value may be limitedly applied to search space sets connected to each other (or PDCCH candidates corresponding to search space sets connected to each other).

10A is a conceptual diagram illustrating a first embodiment of a PDCCH and PDSCH resource allocation method, FIG. 10B is a conceptual diagram illustrating a second embodiment of a PDCCH and PDSCH resource allocation method, and FIG. 10C is a PDCCH and PDSCH resource allocation method It is a conceptual diagram showing the third embodiment.

10A to 10C , the embodiments of FIGS. 10A to 10C may be implemented by (Method 100). The UE may receive DCI(s) in a plurality of PDCCHs (eg, first and second PDCCHs) or a plurality of PDCCH candidates (eg, first and second PDCCH candidates), and the received Scheduling information of the PDSCH (eg, the first PDSCH) may be obtained from the DCI(s). According to the above-described method, a plurality of PDCCH candidates (eg, first and second PDCCH candidates) may be connected to each other.

T1 may mean a time offset from the first PDCCH (or the first PDCCH candidate). T2 may mean a time offset from the second PDCCH (or the second PDCCH candidate). Each time offset may mean a time corresponding to the reception processing time of the first and second PDCCHs performed in the terminal (or the number of symbols corresponding to the time, the number of slots, etc.). According to an embodiment, T1 may be the same as T2. In the embodiment of FIG. 10A , the first PDSCH may be allocated after T1 (or T1 symbols) from the end time of the first PDCCH candidate. In addition, the first PDSCH may be allocated after T2 (or T2 symbols) from the end time of the second PDCCH candidate. The UE may decode DCI during times T1 and T2, and may obtain information about the TCI state (eg, spatial QCL) of the first PDSCH. The UE may form a reception beam for the first PDSCH based on TCI state (eg, spatial QCL) information, and may perform a reception operation of the first PDSCH based on the reception beam. In this case, by the above-described method, each DCI received (or monitored) through the first and second PDCCH candidates may include a TCI field (or information about TCI). Alternatively, one DCI among DCIs received through the first and second PDCCH candidates may include a TCI field (or information about TCI). The UE may receive configuration information of CORESET (hereinafter referred to as "first CORESET") through which the first PDCCH is transmitted and configuration information of CORESET through which the second PDCCH is transmitted (hereinafter referred to as "second CORESET"). . The UE may consider that each DCI received through the first and second PDCCHs includes a TCI field based on configuration information of the first and second CORESETs. Alternatively, the UE may consider that one DCI among DCIs received through the first and second PDCCHs includes the TCI field based on configuration information of the first and second CORESETs.

On the other hand, when each DCI received (or monitored) through the first and second PDCCHs does not include a TCI field, the UE indicates that the first PDSCH has a QCL relationship with at least one CORESET among the first and second CORESETs. can be assumed to have For example, the UE may assume that the first PDSCH has a QCL relationship with the CORESET having a lower or higher ID among the first and second CORESETs. Alternatively, the UE may assume that the first PDSCH has a QCL relationship with CORESET corresponding to a search space set having a low or high ID among search space sets to which the first and second PDCCHs belong. Alternatively, when the first PDSCH precedes the start symbol or the end symbol of the preceding CORESET (eg, PDCCH (or PDCCH candidate) among the first and second CORESETs), the PDCCH (or PDCCH candidate) associated with it CORESET) or a late CORESET (eg, when the start symbol or the end symbol of the PDCCH (or PDCCH candidate) is late, it may be assumed to have a QCL relationship with the CORESET associated with the corresponding PDCCH (or PDCCH candidate)). On the other hand, when only one DCI among DCIs received (or monitored) through the first and second PDCCHs includes TCI status information of the PDSCH, the UE indicates that the first PDSCH includes a PDCCH candidate corresponding to the DCI. It can be assumed to have a relationship between CORESET and QCL. Alternatively, in the above case, the UE may assume that the first PDSCH has a QCL relationship with CORESET satisfying a predetermined condition. For example, a CORESET satisfying a predetermined condition may be a CORESET having the lowest ID (or the highest ID) in the latest slot in which the CORESET(s) exist. A CORESET satisfying a predetermined condition may coincide with the first CORESET or the second CORESET. Alternatively, a CORESET satisfying a predetermined condition may not match the first CORESET or the second CORESET.

In the embodiment of FIG. 10C , the first PDSCH may be allocated before the time after T1 (or T1 symbols) from the reception end time of the first PDCCH (or the first PDCCH candidate). In addition, the first PDSCH may be allocated before a time point after T2 (or T2 symbols) from a reception end time of the second PDCCH (or a second PDCCH candidate). As described above, T1 and T2 may coincide. That is, the first PDSCH may be allocated before the time after T2 (=T1) (or T2 (=T1) symbols) from the end time (eg, end symbol) of the second PDCCH candidate. In this case, it may be difficult for the UE to complete decoding of the first and second PDCCHs before the reception of the first PDSCH. As a result, it may be difficult for the UE to obtain TCI state information for reception of the first PDSCH. In this case, the UE may determine a CORESET having a QCL relationship with the first PDSCH according to a predetermined criterion. For example, the UE has a QCL relationship with the CORESET having the lowest ID (or the highest ID) among the CORESET(s) in the most recent slot in which the first PDSCH CORESET(s) exists. can be assumed. Here, the CORESET(s) may be all CORESET(s) configured in the terminal (eg, all CORESET(s) configured on a carrier or active bandwidth part). Alternatively, the CORESET(s) may be CORESETs (eg, a first CORESET and a second CORESET) corresponding to search space sets connected to each other. The most recent slot may be a slot satisfying the above-described condition among slots before the slot to which the first and second PDCCH candidates (or the first and second PDSCHs) are mapped. Alternatively, the most recent slot may be a slot to which the first and second PDCCH candidates (or the first and second PDSCHs) are mapped and a slot satisfying the above-described condition among slots before the corresponding slot. If "a first PDCCH candidate is mapped to a first slot, a second PDCCH candidate is mapped to a second slot, and the first slot precedes the second slot", the most recent slot is greater than the first slot and the first slot. It may be a slot that satisfies the above-described condition among the above slots. Alternatively, the most recent slot may be a slot satisfying the above-described condition among the second slot and slots preceding the second slot. As another example of the predetermined criterion, the terminal is one of the TCI state (s) of the PDSCH configured (or activated) in the first PDSCH (eg, the TCI state corresponding to the lowest index) is applied. can be considered as

In the embodiment of FIG. 10B , the first PDSCH may be allocated after T1 (or T1 symbols) from the reception end time of the first PDCCH (or the first PDCCH candidate). In addition, the first PDSCH may be allocated before the time point after T2 (or T2 symbols) from the reception end time of the second PDCCH (or the second PDCCH candidate). As described above, T1 and T2 may coincide. In this case, the UE may complete the decoding of the first PDCCH before the reception of the first PDSCH, but it may be difficult to complete the decoding of the second PDCCH. Accordingly, the UE may acquire TCI state information (eg, QCL information) of the first PDSCH only when the first PDCCH is received. In this case, when DCI is successfully received through the first PDCCH candidate, the UE receives for the first PDSCH based on the TCI state information (eg, spatial QCL information) of the first PDSCH obtained from the received DCI. A beam may be formed, and a reception operation of the first PDSCH may be performed based on the reception beam. In addition, when the DCI received through the first PDCCH does not include the TCI field, the UE may assume that the first PDSCH has a QCL relationship with the CORESET through which the first PDCCH is transmitted. The first PDCCH may be generalized to "at least one PDCCH among PDCCH(s) in which a PDCCH reception processing time is secured before a PDSCH reception time". Alternatively, even in the above-described case, the QCL relationship of the first PDSCH may be determined by the method described in the first embodiment of FIG. 10A or the third embodiment of FIG. 10C.

[HARQ-ACK timing indication method]

The UE may report HARQ-ACK information to the base station in response to the reception of the PDSCH. The HARQ-ACK information may be ACK, negative-acknowledgement (NACK), or discontinuous transmission (DTX). HARQ-ACK information may be transmitted through an uplink channel (eg, PUCCH, PUSCH). The base station may set or instruct a feedback timing (eg, transmission timing) of HARQ-ACK to the terminal. The HARQ-ACK transmission timing of the UE (hereinafter referred to as “HARQ-ACK timing”) may be determined based on the PDSCH reception timing. For example, when the PDSCH is received in the nth slot, the nth symbol, or the nth subslot, in the (n+k)th slot, the (n+k)th symbol, or the (n+k)th subslot Transmission of the HARQ-ACK may be indicated or configured to the terminal. Here, each of n and k may be a natural number. The terminal may obtain the k value from the base station. That is, the value of k may be indicated or set to the terminal. Alternatively, the value of k may be predefined in the technical standard, and may be shared between the base station and the terminal.

According to (Method 110), the UE may schedule different PDSCHs through a plurality of PDCCHs, and the plurality of PDSCHs may include the same TB(s). Also, a plurality of PDSCHs may be received in different time resources. Meanwhile, the UE may acquire one HARQ-ACK timing from DCI (eg, DCI payload) received through PDCCHs. The UE may apply the HARQ-ACK timing to each of the plurality of PDSCHs, and may derive the HARQ-ACK timing corresponding to each of the plurality of PDSCHs. HARQ-ACK timings corresponding to each of the plurality of PDSCHs may be different from each other.

11A is a conceptual diagram illustrating a first embodiment of a HARQ-ACK transmission method for the same TB and a plurality of PDSCHs, and FIG. 11B is a second embodiment of a HARQ-ACK transmission method for the same TB and a plurality of PDSCHs. is a conceptual diagram showing

11A and 11B , the embodiments of FIGS. 11A and 11B may be implemented by (method 110). For example, the UE may receive scheduling information of a plurality of PDSCHs (eg, first and second PDSCHs) through a plurality of PDCCHs (eg, first and second PDCCHs). . A plurality of PDSCHs (eg, first and second PDSCHs) may include the same TB(s). A plurality of PDSCHs (eg, first and second PDSCHs) may be received on different time resources. In the embodiment of FIG. 11A , the first PDSCH may be received in slot n, and the second PDSCH may be received in slot n+1. In the embodiment of FIG. 11B , the first PDSCH may be received in a first subslot of slot n, and the second PDSCH may be received in a second subslot of slot n. Here, n may be an integer of 0 or more.

The UE may acquire one HARQ-ACK transmission timing from DCI (eg, DCI payload) received through PDCCHs (eg, first and second PDCCHs). The UE may apply the HARQ-ACK transmission timing to each of a plurality of PDSCHs (eg, first and second PDSCHs), and may derive a HARQ-ACK transmission timing corresponding to each of the plurality of PDSCHs. . HARQ-ACK transmission timings (eg, first and second HARQ-ACK transmission timings) corresponding to the plurality of PDSCHs may be different from each other. In the embodiment of FIG. 11A , the first HARQ-ACK transmission timing may be slot n+2, and the second HARQ-ACK transmission timing may be slot n+3. The UE may transmit the HARQ-ACK through the first PUCCH in slot n+2 and may transmit the HARQ-ACK through the second PUCCH in the slot n+3. In the embodiment of FIG. 11B , the first HARQ-ACK transmission timing may be a first subslot within slot n+1, and the second HARQ-ACK transmission timing may be a second subslot within slot n+1. The UE may transmit the HARQ-ACK through the first PUCCH in the first subslot within the slot n+1, and may transmit the HARQ-ACK through the second PUCCH in the second subslot within the slot n+1.

As in the above-described embodiments, when the UE repeatedly transmits HARQ-ACKs at a plurality of timings for the same downlink TB(s), uplink resource efficiency may decrease. In addition, the base station may perform blind decoding (eg, blind decoding on PUCCH or PUSCH) at a plurality of timings for HARQ-ACK reception. According to this operation, the reception complexity of the base station can be increased.

As a method for solving the above-described problem, a new HARQ-ACK transmission timing indication method may be used. According to the proposed method, the HARQ-ACK transmission timing of the UE may be determined based on a new time point rather than the PDSCH reception timing. For example, the HARQ-ACK transmission timing may be defined as an absolute time within the HARQ frame (eg, a slot, subslot, symbol, or index thereof within the HARQ frame). Here, "index" may be used interchangeably with the meaning of "number". The HARQ frame may be a frame in which HARQ-ACK is transmitted. The terminal receives information about an absolute viewpoint within the HARQ frame from the base station (eg, a specific slot, a specific subslot, a specific symbol, or an index thereof within the HARQ frame) and/or information about the HARQ frame (eg, A specific HARQ frame, or an index thereof) may be received, and HARQ-ACK transmission timing may be derived based on the received information. For example, the above-described information may be included in the scheduling DCI, and the scheduling DCI may be transmitted to the UE through the PDCCH. Here, the “HARQ frame” may be merely a term for referring to a reference time interval for determining the HARQ-ACK transmission timing of the UE. The concept of the HARQ frame may also be referred to by other terms. The method described above may be referred to as (method 200).

12 is a conceptual diagram illustrating a first embodiment of a method for setting an HARQ frame.

Referring to FIG. 12 , one HARQ frame may mean a continuous time interval having a predetermined length or duration. The HARQ frame may appear periodically and repeatedly. HARQ frame n may be adjacent to HARQ frame n+1. Here, n may be an integer of 0 or more. The length of the HARQ frame may be the same as the periodicity of the HARQ frame. The length of the HARQ frame may be referred to as THF. In one radio frame or two consecutive radio frames, p (eg, (10/THF) or (20/THF)) HARQ frame(s) may be disposed. Alternatively, the HARQ frame may include j consecutive radio frames. Here, each of p and j may be an integer. A time offset may be applied to the HARQ frame, and the HARQ frame boundary may not be aligned with the radio frame boundary. For example, one radio frame or two consecutive radio frames may include a partial HARQ frame. Alternatively, one HARQ frame may include a partial radio frame. Each HARQ frame may include contiguous slot(s), contiguous subslot(s), and/or contiguous symbol(s). For example, one HARQ frame may include 10 slots. Indices of slots in the HARQ frame may be one of 0 to 9.

The base station may inform the terminal of the configuration information of the HARQ frame through a signaling procedure. The configuration information of the HARQ frame may include the length of the HARQ frame (ie, THF), the number of slots constituting the HARQ frame (or the number of subslots, the number of symbols), the time offset of the HARQ frame, and the like.

13 is a conceptual diagram illustrating a first embodiment of a method for indicating HARQ-ACK transmission timing according to (Method 200).

Referring to FIG. 13 , the HARQ frame may include 10 consecutive slots. The UE may receive the first PDSCH in slot #1 (or time interval corresponding to slot #1) of HARQ frame #n, and slot #2 (or time corresponding to slot #2) of HARQ frame #n interval) may receive the second PDSCH. For example, the first and second PDSCHs may be scheduled by different PDCCHs by (Method 110). In this case, the base station may indicate the transmission timing of the HARQ-ACK corresponding to the first and second PDSCHs to the terminal through DCI based on (Method 200).

For example, the base station may indicate to the terminal slot #4 (eg, the index of the corresponding slot) of the HARQ frame #n as the HARQ-ACK transmission timing corresponding to the first and second PDSCHs. To support this operation, information actually transmitted to the terminal may include only the slot index (eg, 4) in the HARQ frame. In this case, the HARQ frame to which the HARQ-ACK transmission timing of the terminal belongs is determined by the relationship with the reception timing of "first and second PDSCHs" and/or "PDCCHs corresponding to first and second PDSCHs". can For example, the UE is the earliest HARQ frame among HARQ frame(s) that satisfy "the HARQ-ACK transmission timing exists after M slots (or subslots, symbols) from the PDSCH reception time" (e.g. For example, the HARQ frame #n) may be determined as the HARQ frame in which the HARQ-ACK of the UE is transmitted. M may be a natural number. Alternatively, M may be a positive integer including 0. The M value may be predefined in the technical standard. Together with or separately from the above-described operation, the M value may be set from the base station to the terminal. When the value of M is not set in the terminal, the terminal may assume one default value for M. For example, the default value may be 0 or 1.

Alternatively, the information actually transmitted to the terminal may include a slot index (eg, 4) and a HARQ frame index (eg, n) in the HARQ frame. The terminal may transmit the HARQ-ACK corresponding to the first and second PDSCHs to the base station in slot #4 of the HARQ frame #n based on information received from the base station (eg, n, 4). The HARQ-ACK may be transmitted through a PUCCH (eg, the first PUCCH) or a PUSCH.

In the embodiment of FIG. 11 , the terminal may receive the third PDSCH in slot #9 (or time interval corresponding to slot #9) of HARQ frame #n, and slot #0 ( Alternatively, the fourth PDSCH may be received in a time interval corresponding to slot #0). For example, the third and fourth PDSCHs may be scheduled by different PDCCHs by (Method 110). In this case, the base station may indicate the transmission timing of the HARQ-ACK corresponding to the third and fourth PDSCHs to the terminal through DCI based on (Method 200).

For example, the base station may indicate to the terminal slot #2 (or the index of the corresponding slot) of the HARQ frame #n+1 as HARQ-ACK transmission timings corresponding to the third and fourth PDSCHs. To support this operation, information actually transmitted to the terminal may include only the slot index (eg, 2) in the HARQ frame. The HARQ frame to which the HARQ-ACK transmission timing of the UE belongs may be determined by a relationship with the reception timing of “third and fourth PDSCHs” and/or “PDCCHs corresponding to third and fourth PDSCHs”. Alternatively, the information actually transmitted to the UE may include a slot index (eg, 2) and a HARQ frame index (eg, n+1) in the HARQ frame. The terminal sends HARQ-ACKs corresponding to the third and fourth PDSCHs in slot #2 of the HARQ frame #n+1 to the base station based on the above-described information (eg, n+1, 2) indicated by the base station. can send The HARQ-ACK may be transmitted through a PUCCH (eg, a second PUCCH) or a PUSCH.

The above-described method of indicating HARQ-ACK transmission timing may be used for (Method 110). In addition, the above-described method of indicating the HARQ-ACK transmission timing may be used for general PDSCH transmission (eg, PDSCH transmission by (Method 100), PDSCH transmission scheduled by single PDCCH transmission, etc.).

Meanwhile, according to the above-described method, a plurality of PDCCH candidates or search space sets corresponding to the plurality of PDCCH candidates may be connected to each other for repeated PDCCH transmission. DCIs transmitted from a plurality of PDCCH candidates connected to each other may schedule different PDSCHs by (method 110). In this case, the transmission timing of the HARQ-ACK for the scheduled TB may be determined based on the location of the resource to which one of the plurality of PDSCHs is mapped. For example, the HARQ-ACK transmission timing may be determined based on the resource location of the PDSCH mapped to the latest resource.

14 is a conceptual diagram illustrating a third embodiment of a HARQ-ACK transmission method for the same TB and a plurality of PDSCHs.

Referring to FIG. 14 , the UE may monitor a first PDCCH candidate in slot n and may monitor a second PDCCH candidate in slot (n+1). DCI may be repeatedly transmitted through the first PDCCH candidate and the second PDCCH candidate, and the first PDCCH candidate and the second PDCCH candidate may be connected to each other. DCI transmitted through the first PDCCH candidate and DCI transmitted through the second PDCCH candidate may schedule each of the first PDSCH and the second PDSCH for the same TB (or TBs). The UE may transmit the HARQ-ACK for the TB (or TBs) to the base station through an uplink channel (eg, PUCCH, PUSCH). For example, the HARQ-ACK may be transmitted through the first PUCCH in slot n+3.

At this time, the transmission timing of the HARQ-ACK for the TB (or TBs) is to be determined based on the resource location of the second PDSCH scheduled for a late resource (eg, a late slot) among the first and second PDSCHs. can For example, the UE has a slot distance between the PDSCH and HARQ-ACK through DCI (eg, a slot offset between a PDSCH reception slot and a transmission slot of an uplink channel including HARQ-ACK (eg, PUCCH)). Information indicating that it is 2 may be received. The UE may consider that the slot distance (eg, slot offset) indicated by DCI is the slot distance between the HARQ-ACK from the second PDSCH, and two slots from slot n+1, which is the reception slot of the second PDSCH. HARQ-ACK may be transmitted in slot n+3 after .

The UE may successfully receive DCIs repeatedly transmitted in both the first PDCCH candidate and the second PDCCH candidate. Alternatively, the UE may receive DCI from one PDCCH candidate among the first PDCCH candidate and the second PDCCH candidate, and may not receive DCI from the other PDCCH candidate. For example, the UE may receive the first DCI in the first PDCCH candidate of slot n, and may not receive the second DCI in the second PDCCH candidate of slot n+1. However, since the first DCI and the second DCI are DCIs that are repeatedly transmitted (eg, DCI formats including the same payload), the UE uses the scheduling information of the first DCI even when the second DCI is not received. Thus, it is possible to check the resource location of the second PDSCH. That is, even when the UE does not receive the second DCI, it may be assumed that the second DCI has been received, and the resource location of the PDSCH scheduled by the second DCI may be determined. The second PDSCH and/or the second DCI may actually be transmitted. Alternatively, the second PDSCH and/or the second DCI may not be actually transmitted. Regardless of whether the second PDSCH and/or the second DCI are actually transmitted, the UE transmits the HARQ-ACK transmission timing (e.g., slot n+3) can be determined. "Even when the second DCI (eg, DCI scheduling the PDSCH, which is the derivation criterion of HARQ-ACK transmission timing) is received, and the first DCI (eg, DCI scheduling another PDSCH) is not received" , the UE may determine the HARQ-ACK transmission timing (eg, slot n+3) based on the resource location (eg, slot n+1) of the second PDSCH. The method described above may be referred to as (Method 210).

In (Method 210), a PDSCH that is a derivation criterion for HARQ-ACK transmission timing may be a PDSCH scheduled for a late resource. Specifically, a PDSCH scheduled for a late resource may be a PDSCH mapped to a late slot or a later symbol set. Alternatively, the PDSCH scheduled for a late resource may be a PDSCH having a late end symbol (or a late start symbol). Alternatively, the PDSCH, which is a derivation criterion for HARQ-ACK transmission timing, may be a PDSCH scheduled for an early resource. Specifically, a PDSCH scheduled for an early resource may be a PDSCH mapped to an early slot or an early symbol set. Alternatively, the PDSCH scheduled for an early resource may be a PDSCH having an early end symbol (or an early start symbol). As another method, the PDSCH, which is a derivation criterion for HARQ-ACK transmission timing, may be a PDSCH scheduled by a specific PDCCH candidate. For example, a specific PDCCH candidate is "a PDCCH candidate belonging to a search space set with a specific search space set ID", "a PDCCH candidate belonging to a CORESET with a specific CORESET ID", or "a search space mapped to an early resource or a late resource" PDCCH candidates belonging to the set”.

In the above-described embodiment, DCIs transmitted in the first PDCCH candidate and the second PDCCH candidate may schedule repetitively transmitted PDSCHs. For example, the first PDSCH scheduled by the first PDCCH candidate may be repeatedly transmitted, and the second PDSCH scheduled by the second PDCCH candidate may be repeatedly transmitted. In this case, the transmission timing of the HARQ-ACK for the scheduled TB may be determined based on the resource location of the last PDSCH (or PDSCH instance) constituting the first repeated PDSCH transmission or the second repeated PDSCH transmission. For example, the transmission timing (eg, transmission slot) of the HARQ-ACK for the scheduled TB is the last PDSCH (eg, the second PDSCH repeated transmission) constituting the PDSCH repeated transmission (eg, the second PDSCH repeated transmission) allocated to the late resource. , PDSCH instance) may be determined based on the resource location (eg, slot). In addition, when different PDSCH repeated transmissions are scheduled by repeatedly transmitted DCIs, each PDSCH (or each PDSCH instance) constituting one repeated PDSCH transmission (eg, the first PDSCH repeated transmission) is It may be allocated to a resource earlier than all PDSCHs (or PDSCH instances) constituting another repeated PDSCH transmission (eg, repeated second PDSCH transmission).

In the above-described embodiment, the UE may receive the same DCI (eg, the same DCI format) in the first PDCCH candidate and the second PDCCH candidate connected to each other. Alternatively, the UE may receive different DCIs (eg, DCI format) in each of the first PDCCH candidate and the second PDCCH candidate connected to each other. For example, the UE may receive DCI (eg, DCI format) for scheduling different TBs in each of a first PDCCH candidate and a second PDCCH candidate connected to each other. This operation may be performed when the resource of at least one PDCCH candidate among the first PDCCH candidate and the second PDCCH candidate completely overlaps with the resource of the PDCCH candidate belonging to another search space set (eg, another USS set). . In this case, the transmission timing of the HARQ-ACK corresponding to the scheduled TB may be determined by a method other than (Method 210). That is, (Method 210) may be used only in cases other than the above cases. For example, in the above case, the UE may determine the transmission timing (eg, slot, subslot) of the HARQ-ACK corresponding to the PDSCH scheduled from each DCI based on the resource location in which each PDSCH is scheduled. and may transmit each HARQ-ACK at the determined transmission timing.

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, and the like, 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 configuration information of a resource set for a physical downlink control channel (PDCCH) monitoring operation from the base station;
performing the PDCCH monitoring operation on the resource set;
receiving at least one downlink control information (DCI) including scheduling information of a first physical downlink shared channel (PDSCH) by the PDCCH monitoring operation; and
Receiving the first PDSCH based on the scheduling information,
The resource set includes a first search space and a second search space for repeated PDCCH transmission, the first search space is used for transmission of a first DCI, and the second search space is used for transmission of a second DCI used, wherein the at least one DCI is at least one DCI of the first DCI and the second DCI, the first DCI and the second DCI include the same payload, and the format of the first DCI is the first DCI. 2 The same as the format of DCI, the operating method of the terminal. The method according to claim 1,
The first DCI is received based on information about a quasi-co-location (QCL) of a first control resource set (CORESET) combined with the first search space, and the second DCI includes the second search space and A method of operating a terminal, which is received based on the combined information on the QCL of the second CORESET, and the information on the QCL of the first CORESET and the information on the QCL of the second CORESET are determined independently of each other. The method according to claim 1,
When the first CORESET combined with the first search space is the same as the second CORESET combined with the second search space, the first DCI and the second DCI are received based on information about the same QCL. how it works. The method according to claim 1,
The first PDSCH is received based on transmission configuration information (TCI) state information for the first PDSCH, and the configuration information of the first CORESET combined with the first search space includes the TCI state information to the first DCI. It includes first information indicating whether it is included, and the configuration information of the second CORESET combined with the second search space includes second information indicating whether the TCI state information is included in the second DCI, and The first information and the second information are the same, the operating method of the terminal. The method according to claim 1,
When the first DCI and the second DCI do not include TCI state information for the first PDSCH, the reception operation of the first PDSCH includes a first CORESET in which the first PDSCH is combined with the first search space and The method of operating a terminal, which is performed based on the assumption that the CORESET having a smaller ID and QCL are performed among the second CORESETs combined with the second search space. The method according to claim 1,
If the number of symbols between at least one end symbol of the first DCI end symbol and the second DCI end symbol and the first PDSCH start symbol is less than or equal to a reference value, the reception operation of the first PDSCH is performed when the first PDSCH is A method of operating a terminal, which is performed based on the assumption that one CORESET and QCL in the most recent slot including one or more CORESETs are performed. 7. The method of claim 6,
The one CORESET is a first CORESET combined with the first search space or a second CORESET combined with the second search space. The method according to claim 1,
and the first search space and the second search space are set to the same search space set type, and the same search space set type is a terminal-specific search space or a common search space. The method according to claim 1,
A first PDCCH including the first DCI is transmitted through a first PDCCH candidate in the first search space, and a second PDCCH including the second DCI is transmitted through a second PDCCH candidate in the second search space. and the first PDCCH candidate and the second PDCCH candidate have the same control channel element (CCE) aggregation level and the same PDCCH candidate index. 10. The method of claim 9,
The first PDCCH candidate is configured to be connected to the second PDCCH candidate for the repeated PDCCH transmission. 10. The method of claim 9,
The step of performing the PDCCH monitoring operation includes:
and performing a monitoring operation of the second PDCCH candidate without performing the monitoring operation of the first PDCCH candidate when the first PDCCH candidate satisfies a predefined condition. 12. The method of claim 11,
The predefined conditions include a condition in which the first PDCCH candidate overlaps a synchronization signal/physical broadcast channel (SS/PBCH) block, a condition in which the first PDCCH candidate overlaps a physical random access channel (PRACH) resource, and the second A method of operating a terminal, comprising at least one of a condition in which one PDCCH candidate overlaps an uplink symbol and a condition in which the first search space is excluded from mapping by a search space mapping rule. A method of operating a base station in a communication system, comprising:
transmitting configuration information of a resource set for a physical downlink control channel (PDCCH) monitoring operation to the terminal;
transmitting at least one downlink control information (DCI) including scheduling information of a first physical downlink shared channel (PDSCH) from the resource set to the terminal; and
Transmitting the first PDSCH to the terminal based on the scheduling information,
The resource set includes a first search space and a second search space for repeated PDCCH transmission, the first search space is used for transmission of a first DCI, and the second search space is used for transmission of a second DCI used, wherein the at least one DCI is at least one DCI of the first DCI and the second DCI, the first DCI and the second DCI include the same payload, and the format of the first DCI is the first DCI. 2 The same as the format of DCI, the operation method of the base station. 14. The method of claim 13,
The information on the quasi-co-location (QCL) of the first control resource set (CORESET) combined with the first search space is determined independently of the information on the QCL of the second CORESET combined with the second search space. A method of operating a base station. 14. The method of claim 13,
The configuration information of the first CORESET combined with the first search space includes first information indicating whether transmission configuration information (TCI) state information for the first PDSCH is included in the first DCI, and the second The configuration information of the second CORESET combined with the search space includes second information indicating whether the TCI state information is included in the second DCI, and the first information is the same as the second information. . 14. The method of claim 13,
When the first DCI and the second DCI do not include the TCI state information for the first PDSCH, the reception operation of the first PDSCH in the terminal is performed in which the first PDSCH is combined with the first search space. 1 CORESET and the second CORESET combined with the second search space, which is performed based on the assumption that the CORESET having a smaller ID and QCL are performed. 14. The method of claim 13,
When the number of symbols between at least one end symbol of the first DCI end symbol and the second DCI end symbol and the start symbol of the first PDSCH is less than or equal to a reference value, the reception operation of the first PDSCH in the UE is the first 1 The method of operating a base station, which is performed based on the assumption that the PDSCH is QCL with one CORESET in the most recent slot including one or more CORESETs. 14. The method of claim 13,
The method of claim 1, wherein the first search space and the second search space are set to the same search space set type, and the same search space set type is a terminal-specific search space or a common search space. 14. The method of claim 13,
A first PDCCH including the first DCI is transmitted through a first PDCCH candidate in the first search space, and a second PDCCH including the second DCI is transmitted through a second PDCCH candidate in the second search space. and the first PDCCH candidate and the second PDCCH candidate have the same control channel element (CCE) aggregation level and the same PDCCH candidate index. 20. The method of claim 19,
The method of operating a base station, wherein the first PDCCH candidate is configured to be connected to the second PDCCH candidate for the repeated PDCCH transmission.

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