WO2024225885A1 - Method for receiving downlink channel, user equipment and storage medium, and method for transmitting downlink channel, and base station - Google Patents

Abstract

In some embodiments of the present specification, a CORESET comprises: one or more RB sets each including a plurality of consecutive RBs in a frequency domain; and one or more OFDM symbols in a time domain, wherein: a PDCCH has one or more CCEs in the CORESET; and each CCE in the CORESET can be defined to be the same as one interlace during an OFDM symbol in an RB set for the CORESET.

Description

Method for receiving a downlink channel, user device and storage medium, and method for transmitting a downlink channel and base station

This specification relates to wireless communication systems.

Various devices and technologies such as machine-to-machine (M2M) communication, machine type communication (MTC), and smart phones and tablet PCs (Personal Computers) that require high data transmission rates are emerging and becoming widespread. Accordingly, the amount of data required to be processed in cellular networks is increasing very rapidly. In order to satisfy this rapidly increasing demand for data processing, carrier aggregation technology and cognitive radio technology for efficient use of more frequency bands, multi-antenna technology for increasing the data capacity transmitted within a limited frequency, and multi-base station (BS) cooperation technology are being developed.

A wireless communication system supports communication of user equipment (UEs) by utilizing available system resources (e.g., bandwidth, transmission power, etc.). With the introduction of new wireless communication technologies, not only the number of UEs to which a base station (BS) must provide services in a given resource area increases, but also the amount of data and control information transmitted/received by the BS to/from the UEs it provides services to also increases. Since the amount of radio resources that the BS can use for communication with the UE(s) is finite, a new method is required for the BS to efficiently receive/transmit uplink/downlink data and/or uplink/downlink control information from/to the UE(s) by utilizing the finite radio resources. In other words, as the density of nodes and/or the density of UEs increases, a method is required for efficiently utilizing a high density of nodes or a high density of UEs for communication.

Considering the rapidly increasing volume of communications, there has been discussion about utilizing shared spectrum, which is unlicensed spectrum that is not licensed to a specific network operator and can be freely used by multiple network operators.

There are some aspects in which operations in a licensed spectrum, which is licensed to a specific network operator and can be used exclusively or preferentially by the network operator, are difficult to apply as is to shared spectrum, which is an unlicensed spectrum that can be freely used by multiple network operators. Considering the unique characteristics of shared spectrum or considering the possibility that operations considering shared spectrum can be applied to unshared spectrum, wireless communication technologies suitable for or considering shared spectrum operations need to be specified.

The technical problems to be solved by this specification are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art related to this specification from the detailed description below.

In one aspect of the present specification, a method for a user equipment to receive a downlink channel in a wireless communication system is provided. The method includes: receiving a configuration regarding a control resource set (CORESET); and monitoring a set of physical downlink control channel (PDCCH) candidates based on the configuration; and detecting a downlink control information (DCI) format within the set of PDCCH candidates. The CORESET comprises N ^CORESET _RB-set RB sets, each of which comprises a plurality of contiguous resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain, and each PDCCH candidate within the CORESET comprises one or more control channel elements (CCEs), and each CCE within the CORESET is identical to one interlace during an OFDM symbol within the RB set for the CORESET.

In another aspect of the present disclosure, a user equipment for receiving a downlink channel in a wireless communication system is provided. The user equipment includes: at least one transceiver; at least one processor; and at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The operations include: receiving a configuration regarding a control resource set (CORESET); and monitoring a set of physical downlink control channel (PDCCH) candidates based on the configuration; and detecting a downlink control information (DCI) format within the set of PDCCH candidates. The CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes a plurality of consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain, and each PDCCH candidate in the CORESET is composed of one or more control channel elements (CCEs), and each CCE in the CORESET is equivalent to one interlace during an OFDM symbol in the RB set for the CORESET.

In another aspect of the present disclosure, a processing device is provided. The processing device includes: at least one processor; and at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The operations include: receiving a configuration regarding a control resource set (CORESET); and monitoring a set of physical downlink control channel (PDCCH) candidates based on the configuration; and detecting a downlink control information (DCI) format within the set of PDCCH candidates. The CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes a plurality of consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain, and each PDCCH candidate in the CORESET is composed of one or more control channel elements (CCEs), and each CCE in the CORESET is equivalent to one interlace during an OFDM symbol in the RB set for the CORESET.

In another aspect of the present disclosure, a computer-readable non-transitory storage medium is provided comprising at least one computer program causing at least one processor to perform operations. The operations include: receiving a configuration regarding a control resource set (CORESET); and monitoring a set of physical downlink control channel (PDCCH) candidates based on the configuration; and detecting a downlink control information (DCI) format within the set of PDCCH candidates. The CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes a plurality of consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain, and each PDCCH candidate in the CORESET is composed of one or more control channel elements (CCEs), and each CCE in the CORESET is equivalent to one interlace during an OFDM symbol in the RB set for the CORESET.

In another aspect of the present specification, a method for transmitting a downlink channel by a base station in a wireless communication system is provided. The method includes: transmitting a configuration regarding a control resource set (CORESET); and transmitting a downlink control information (DCI) format within a set of physical downlink control channel (PDCCH) candidates based on the configuration. The CORESET includes N ^CORESET _RB-set RB sets, each of which includes a plurality of contiguous resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain, and each PDCCH candidate in the CORESET includes one or more control channel elements (CCEs), and each CCE in the CORESET is identical to one interlace during an OFDM symbol in the RB set for the CORESET.

In another aspect of the present disclosure, a base station for transmitting a downlink channel in a wireless communication system is provided. The base station includes: at least one transceiver; at least one processor; and at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The operations include: transmitting a configuration regarding a control resource set (CORESET); and transmitting a downlink control information (DCI) format within a set of physical downlink control channel (PDCCH) candidates based on the configuration. The CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes a plurality of consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain, and each PDCCH candidate in the CORESET is composed of one or more control channel elements (CCEs), and each CCE in the CORESET is equivalent to one interlace during an OFDM symbol in the RB set for the CORESET.

In each aspect of this specification, each of said one or more interlaces may be composed of a plurality of non-contiguous RBs.

For each aspect of this specification, the CCEs within the CORESET may be numbered in increasing order in a frequency-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered interlace within the CORESET.

For each aspect of this specification, the CCEs within the CORESET may be numbered in increasing order in a time-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered interlace within the CORESET.

In each aspect of this specification, the configuration may include the number of PDCCH candidates per aggregation level L. Each PDCCH candidate of the aggregation level L may include L CCEs in the COREST.

In each aspect of this specification, each PDCCH candidate within the CORESET may be composed of CCEs from one RB set.

In each aspect of this specification, each PDCCH candidate within the CORESET may be composed of CCEs from multiple RB sets.

In each aspect of this specification, two adjacent RB sets among the N ^CORESET _RB-set RB sets in the CORESET may have a guard band between the two adjacent RB sets.

In each aspect of this specification, each CCE within the CORESET may not be mapped to an interlace where some of the RBs are included in the guard band.

In each aspect of this specification, the CORESET may include CCEs mapped to interlaces where some of the RBs are included in the guard band.

The above problem solving methods are only some of the examples of this specification, and various examples reflecting the technical features of this specification can be derived and understood by a person having ordinary knowledge in the relevant technical field based on the detailed description below.

According to some implementation(s) of this specification, wireless communication signals can be transmitted/received efficiently. Accordingly, the overall throughput of the wireless communication system can be increased.

Some implementations of this specification enable efficient wireless communications over shared spectrum, which is an unlicensed spectrum that is not licensed to a specific network operator and can be freely used by multiple network operators.

Some implementations of this specification may enable more efficient use of radio resources on shared spectrum.

According to some implementations of this specification, the transmission/reception performance of a physical downlink control channel can be improved for operations involving shared spectrum channel access.

According to some implementations of this specification, the transmission/reception performance of a physical downlink control channel can be improved in a cell or frequency band where interlace-based transmission is applied.

The effects according to this specification are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art related to this specification from the detailed description below.

FIG. 1 is an example of a communication system 1 to which implementations of the present specification can be applied;

FIG. 2 is a block diagram illustrating examples of communication devices capable of performing a method according to the present specification;

Figure 3 illustrates an example of a frame structure available in a 3GPP-based wireless communication system;

Figure 4 illustrates a resource grid of slots;

FIG. 5 illustrates an example of a physical downlink control channel (PDCCH) structure used in a 3GPP-based wireless communication system;

Figure 6 illustrates mapping methods between control channel elements (CCEs) and resource element groups (REGs);

Figure 7 illustrates a resource block (RB) interlace;

Figure 8 illustrates interlaced RB-based uplink resource allocation in a shared spectrum;

FIGS. 9 and 10 are diagrams illustrating the basic concept of an interlace-based PDCCH structure according to some implementations of the present specification;

FIG. 11 illustrates examples of interlace-to-control channel element (CCE) mapping for interlace-based PDCCH according to some implementations of the present specification;

Figures 12 and 13 illustrate examples of control channel element (CCE) aggregation according to some implementations of the present specification.

FIGS. 14 to 18 illustrate examples of transmitting a PDCCH across multiple resource block sets according to some implementations of the present specification;

FIG. 19 illustrates part of a process by which a user device receives a downlink channel according to some implementations of this specification;

FIG. 20 illustrates part of a process by which a base station transmits a downlink channel according to some implementations of the present specification;

Figure 21 illustrates a PDCCH transmission/monitoring flow according to some implementations of this specification.

Hereinafter, implementations according to this specification will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to describe exemplary implementations of this specification and is not intended to represent the only implementation forms in which this specification may be practiced. The detailed description below includes specific details in order to provide a thorough understanding of this specification. However, one of ordinary skill in the art will appreciate that this specification may be practiced without these specific details.

In some cases, in order to avoid ambiguity in the concepts of this specification, well-known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device. In addition, the same components are described using the same drawing reference numerals throughout this specification.

The techniques, devices, and systems described below can be applied to various wireless multiple access systems.

For convenience of explanation, the following description is based on a 3rd Generation Partnership Project (3GPP)-based communication system. However, the technical features of the present specification are not limited thereto. For example, even if the detailed description below is based on a 3rd Generation Partnership Project (3GPP) LTE or 5G technology, some implementations of the present specification are applicable to any other mobile communication system and systems to be introduced in the future (e.g., 6G) except for the specifics of 3GPP LTE/5G.

For terms and technologies used in this specification that are not specifically explained, refer to 3GPP-based standard documents, such as 3GPP TS 23.304, 3GPP TS 23.285, 3GPP TS 23.287, 3GPP TS 24.587, 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.300, 3GPP TS 36.321, 3GPP 36.322, 3GPP TS 36.323, 3GPP TS and 3GPP TS 36.331, 3GPP TS 37.213, 3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.214, 3GPP TS 38.300, 3GPP TS 38.321, 3GPP TS 38.322, 3GPP TS 38.323, and 3GPP TS 38.331.

In the examples of this specification described below, the expression that a device "assumes" may mean that a subject transmitting a channel transmits the channel in a manner consistent with the "assumption." It may mean that a subject receiving the channel receives or decodes the channel in a form consistent with the "assumption," under the premise that the channel was transmitted in a manner consistent with the "assumption."

In this specification, UE may be fixed or mobile, and includes various devices that communicate with a BS (base station, BS) to transmit and/or receive user data and/or various control information. UE may be called (Terminal Equipment), MS (Mobile Station), MT (Mobile Terminal), UT (User Terminal), etc. In addition, in this specification, BS generally refers to a fixed station that communicates with UE and/or other BS, and exchanges various data and control information with UE and other BS. BS may be called by other terms such as ABS (Advanced Base Station), NB (Node-B), eNB (evolved-NodeB), gNB, BTS (Base Transceiver System), Access Point, and PS (Processing Server). For convenience of explanation, base stations are collectively referred to as BSs regardless of the type or version of communication technology.

In this specification, a node refers to a fixed point that can communicate with a UE and transmit/receive a radio signal. Various types of BSs can be used as nodes regardless of their names. At least one antenna is installed in a node. The antenna may mean a physical antenna, or may mean an antenna port, a virtual antenna, or an antenna group. A node is also called a point.

Meanwhile, 3GPP-based communication systems use the concept of cells to manage radio resources, and cells associated with radio resources are distinguished from cells of geographical areas. The "cell" of a geographical area can be understood as a coverage in which a node can provide a service using a carrier, and the "cell" of radio resources is associated with a bandwidth (BW), which is a frequency range configured by the carrier. Since the downlink coverage, which is a range in which a node can transmit a valid signal, and the uplink coverage, which is a range in which a node can receive a valid signal from a UE, depend at least in part on the carrier carrying the signal, the coverage of a node is also associated with the coverage of the "cell" of radio resources used by the node. Therefore, the term "cell" can sometimes be used to mean the coverage of a service by a node, sometimes a radio resource, and sometimes a range in which a signal using the radio resource can reach with a valid intensity.

A "cell" associated with wireless resources can be defined as a combination of downlink resources (DL resources) and uplink resources (UL resources), i.e., a combination of a DL component carrier (CC) and an UL CC. A cell can be configured with only DL resources, or a combination of DL resources and UL resources. When carrier aggregation is supported, the linkage between the carrier frequency of the DL resources (or DL CC) and the carrier frequency of the UL resources (or UL CC) can be indicated by system information. Here, the carrier frequency can be the same as or different from the center frequency of each cell or CC depending on the system configuration.

In a wireless communication system, a UE receives information from a BS via a downlink (DL), and the UE transmits information to the BS via an uplink (UL). The information transmitted and/or received by the BS and the UE includes data and various control information, and various physical channels exist depending on the type/purpose of the information they transmit and/or receive.

3GPP-based communication standards define downlink physical channels corresponding to resource elements carrying information originating from a higher layer, and downlink physical signals corresponding to resource elements used by the physical layer but not carrying information originating from a higher layer. For example, a physical downlink shared channel (PDSCH), a physical broadcast channel (PBCH), a physical downlink control channel (PDCCH), etc. are defined as downlink physical channels, and a reference signal and a synchronization signal are defined as downlink physical signals. A reference signal (RS), also referred to as a pilot, means a signal with a predefined special waveform and/or pattern known to the BS and the UE. For example, a demodulation reference signal (DMRS), a channel state information RS (CSI-RS), etc. are defined as downlink reference signals. 3GPP-based communication standards define uplink physical channels corresponding to resource elements carrying information originating from higher layers, and uplink physical signals corresponding to resource elements used by the physical layer but not carrying information originating from higher layers. For example, physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH), and physical random access channel (PRACH) are defined as uplink physical channels, and demodulation reference signal (DMRS) for uplink control/data signals and sounding reference signal (SRS) used for uplink channel measurement are defined.

In this specification, PDCCH means a set of time-frequency resources (e.g., resource elements (REs)) carrying downlink control information (DCI), and PDSCH means a set of time-frequency resources carrying downlink data. In addition, PUCCH, PUSCH, and PRACH mean sets of time-frequency resources carrying uplink control information (UCI), uplink data, and random access preamble, respectively. Hereinafter, the expression that a UE/BS transmits/receives a PUCCH/PUSCH/PRACH is used to have an equivalent meaning that it transmits/receives UCI/uplink data/random access preamble on or through the PUCCH/PUSCH/PRACH, respectively. Additionally, the expression that BS/UE transmits/receives PBCH/PDCCH/PDSCH is used with the same meaning as transmitting/receiving broadcast information/DCI/downlink data on or through PBCH/PDCCH/PDSCH, respectively.

In this specification, radio resources (e.g., time-frequency resources) scheduled or configured by the BS to the UE for transmission or reception of PUCCH/PUSCH/PDSCH are also referred to as PUCCH/PUSCH/PDSCH resources.

Since a communication device receives a physical channel and/or a physical signal in the form of radio signals on a cell, it cannot selectively receive only radio signals including only a specific physical channel or a specific physical signal through a radio frequency (RF) receiver, or selectively receive only radio signals excluding only a specific physical channel or a physical signal through an RF receiver. In actual operation, the communication device first receives radio signals on a cell through an RF receiver, converts the radio signals, which are RF band signals, into baseband signals, and decodes the physical signals and/or physical channels within the baseband signals using one or more processors. Therefore, in some implementations of the present specification, not receiving a physical signal and/or a physical channel may not actually mean that the communication device does not receive radio signals including the physical signal and/or the physical channel at all, but may mean that it does not attempt to restore the physical signal and/or the physical channel from the radio signals, for example, it does not attempt to decode the physical signal and/or the physical channel.

Figure 1 is an example of a communication system 1 to which implementations of the present specification can be applied.

Referring to Fig. 1, a communication system (1) applied to this specification includes a wireless device, a BS, and a network. Here, the wireless device may mean a device that performs communication using a wireless access technology (e.g., 5G NR (New RAT), LTE (e.g., E-UTRA), WiFi, 6G to be introduced in the future, etc.).

Although not limited thereto, the wireless devices may include a robot (100a), a vehicle (100b-1, 100b-2, 100b-3, 100b-4), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Thing) device (100f), and an AI device/server (400). For example, the vehicles may include a ground vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing communication between vehicles, etc. Here, the vehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone) and an Urban Air Mobility (UAM) (e.g., an unmanned aerial vehicle). The XR devices may include an AR (Augmented Reality)/VR (Virtual Reality)/MR (Mixed Reality) device. Portable devices may include smartphones, smart pads, wearable devices (e.g., smart watches, smart glasses), computers (e.g., laptops, etc.). Home appliances may include TVs, refrigerators, washing machines, etc.. IoT devices may include sensors, smart meters, etc. For example, BS and networks may also be implemented as wireless devices, and a specific wireless device may act as a BS/network node to other wireless devices.

Wireless devices (100a to 100f) can be connected to a network through a BS (200). AI (Artificial Intelligence) technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) through a network. The wireless devices (100a to 100f) can communicate with each other through the BS (200)/network, but can also communicate directly (e.g. sidelink communication) without going through the BS/network. For example, transportation devices (100b-1, 100b-2, 100b-3, 100b-4) can communicate directly (e.g. V2V (Vehicle to Vehicle)/V2X (Vehicle to everything) communication). Additionally, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

Wireless communication/connection can be established between wireless devices (100a~100f)/BS(200) - BS(200)/wireless devices (100a~100f). Here, the wireless communication/connection can be established through uplink/downlink communication (UL/DL) and sidelink communication (SL) (or, D2D communication) via various wireless access technologies (e.g., 5G NR). Through the wireless communication/connection (UL/DL, SL), the wireless device and the BS/wireless device can transmit/receive wireless signals to/from each other. To this end, at least some of various configuration information setting processes for transmitting/receiving wireless signals, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, resource mapping/demapping, etc.), resource allocation processes, etc. can be performed based on various proposals of this specification.

FIG. 2 is a block diagram illustrating examples of communication devices that can perform a method according to the present specification. Referring to FIG. 2, a first wireless device (100) and a second wireless device (200) can transmit and/or receive wireless signals via various wireless access technologies. Here, {the first wireless device (100), the second wireless device (200)} can correspond to {the wireless device (100x), the BS (200)} and/or {the wireless device (100x), the wireless device (100x)} of FIG. 1.

Each of the first wireless device (100) and the second wireless device (200) includes one or more processors (102, 202) and one or more memories (104, 204), and may additionally include one or more transceivers (106, 206) and/or one or more antennas (108). The processor (102, 202) controls the memories (104, 204) and/or the transceivers (106, 206), and may be configured to implement the functions, procedures, and/or methods described/suggested below. For example, the processor (102, 202) may process information in the memories (104, 204) to generate first information/signal, and then transmit a wireless signal including the first information/signal via the transceivers (106, 206). In addition, the processor (102, 202) may receive a wireless signal including second information/signal through the transceiver (106, 206), and then store information obtained from signal processing of the second information/signal in the memory (104, 204). The memory (104, 204) may be connected to the processor (102, 202) and may store various information related to the operation of the processor (102, 202). For example, the memory (104, 204) may perform some or all of the processes controlled by the processor (102, 202), or store software code including commands for performing the procedures and/or methods described/suggested below. Here, the processor (102, 202) and the memory (104, 204) may be part of a communication modem/circuit/chip designed to implement wireless communication technology. A transceiver (106, 206) may be coupled to a processor (102, 202) and may transmit and/or receive wireless signals via one or more antennas (108, 208). The transceiver (106, 206) may include a transmitter and/or a receiver.

Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, the one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, a service data adaption protocol (SDAP) layer). The one or more processors (102, 202) may generate one or more protocol data units (PDUs) and/or one or more service data units (SDUs) in accordance with the functions, procedures, suggestions and/or methods disclosed in this specification. One or more processors (102, 202) may generate messages, control information, data or information according to the functions, procedures, proposals and/or methods disclosed in this specification. One or more processors (102, 202) may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and/or methods disclosed in this specification and provide them to one or more transceivers (106, 206). One or more processors (102, 202) may receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and/or methods disclosed in this document.

The one or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The one or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof, and the firmware or software may be implemented to include modules, procedures, functions, etc. The firmware or software configured to perform the functions, procedures, suggestions, and/or methods disclosed in this specification may be included in the one or more processors (102, 202) or stored in one or more memories (104, 204) and executed by the one or more processors (102, 202). The functions, procedures, suggestions, and/or methods disclosed in this specification may be implemented using firmware or software in the form of code, instructions, and/or sets of instructions.

One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions and/or commands. The one or more memories (104, 204) may be located internally and/or externally to one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to one or more processors (102, 202) via various technologies, such as wired or wireless connections.

One or more transceivers (106, 206) may transmit/receive user data, control information, wireless signals/channels, etc., referred to in the methods and/or flowcharts of this specification, to/from one or more other devices. In addition, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit/receive user data, control information, or wireless signals to/from one or more other devices. In addition, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and/or receive user data, control information, wireless signals/channels, etc., referred to in the functions, procedures, suggestions, methods, and/or flowcharts of this specification, via one or more antennas (108, 208). In this specification, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) may convert received user data, control information, wireless signals/channels, etc. from RF band signals to baseband signals for processing using one or more processors (102, 202). One or more transceivers (106, 206) may convert processed user data, control information, wireless signals/channels, etc. from baseband signals to RF band signals using one or more processors (102, 202). For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and/or a filter.

In this specification, at least one memory (104, 204) can store instructions or programs, which, when executed, cause at least one processor (102, 202) operably connected to the at least one memory to perform operations according to some embodiments or implementations of the present specification.

In this specification, a computer-readable (non-transitory) storage medium can store at least one instruction or a computer program, which when executed by at least one processor causes the at least one processor to perform operations according to some embodiments or implementations of the present specification.

Figure 3 illustrates an example of a frame structure available in a 3GPP-based wireless communication system.

The structure of the frame in Fig. 3 is only an example, and the number of subframes, the number of slots, and the number of symbols in the frame can be variously changed. In some wireless communication systems, OFDM numerologies (e.g., subcarrier spacing (SCS)) may be set differently between multiple cells aggregated to one UE. Accordingly, the (absolute time) duration of time resources (e.g., subframes, slots, or transmission time intervals (TTIs)) composed of the same number of symbols may be set differently between the aggregated cells. Here, the symbol may include an OFDM symbol (or a cyclic prefix - orthogonal frequency division multiplexing (CP-OFDM) symbol), an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol). In this specification, the terms symbol, OFDM-based symbol, OFDM symbol, CP-OFDM symbol and DFT-s-OFDM symbol are interchangeable.

Referring to FIG. 3, uplink and downlink transmissions are organized into frames. Each frame has a duration T _f = (△f _max *N _f /100)*T _c = 10 ms, where T _c = 1/(△f _max *N _f ) is the basic time unit, △f _max = 480*10 ³ Hz, and N _f =4096. For reference, the sampling time T _s = 1/(△f _ref *N _f,ref ), △f _ref = 15*10 ³ Hz, and N _f,ref =2048. T _c and T _f have a constant relationship κ = T _s /T _c = 64. A frame consists of 10 subframes, and the duration T _sf of a single subframe is 1 ms. Subframes are further divided into slots, and the number of slots in a subframe depends on the subcarrier spacing. Each slot can consist of N ^slot _symb symbols based on a cyclic prefix (CP). For example, in some scenarios, each slot consists of 14 OFDM symbols for the normal CP, and each slot consists of 12 OFDM symbols for the extended CP. The numerology depends on the exponentially scalable subcarrier spacing △f = 2 ^u *15 kHz. The following table shows the number of OFDM symbols per slot ( N ^slot _symb ), the number of slots per frame ( N ^frame,u _slot ), and the number of slots per subframe ( N ^subframe,u _slot ) for the normal CP with the subcarrier spacing △f = 2 ^u *15 kHz.

The following table shows the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per subframe according to the subcarrier spacing △f = 2 ^u *15 kHz for the extended CP.

For a subcarrier spacing setting u, slots are numbered in increasing order within a subframe as n ^u _s ∈ {0, ..., n ^subframe,u _slot - 1} and in increasing order within a frame as n ^u _s,f ∈ {0, ..., n ^frame,u _slot - 1}.

Hereinafter, implementations of the present specification are described by referring to the minimum unit of time for scheduling uplink, downlink, and sidelink transmissions as a slot; however, the minimum unit of time for scheduling may be referred to by a different term depending on the wireless communication system. For example, in an LTE-based system, the minimum unit of time for scheduling transmissions is referred to as a subframe or a transmission time interval (TTI), whereas in an NR-based system, the minimum unit of time for scheduling is referred to as a slot.

Fig. 4 illustrates a resource grid of a slot. A slot contains a plurality of (e.g., N ^slot _symb ) symbols in the time domain. For each numeral (e.g., subcarrier spacing) and carrier, a resource grid of N ^size,u _grid,x * N ^RB sc subcarriers and N subframe,u ^symb OFDM symbols is defined, starting from a common resource block (CRB) N ^start,u _grid indicated by higher layer signaling (e.g., radio resource control (RRC) signaling). Here, N ^size,u _grid,x is the number of resource blocks ( _RBs ) in the resource grid, and the subscript x is _DL for downlink and UL for uplink. N ^RB _sc is the number of subcarriers per RB, and N ^RB _sc is typically 12 in 3GPP-based wireless communication systems. For a given antenna port p , subcarrier spacing configuration u , and transmission direction (DL or UL), there is one resource grid. The carrier bandwidth N ^size,u _grid for subcarrier spacing configuration u is given to the UE by higher-layer parameters (e.g., RRC parameters) from the network. Each element in the resource grid for antenna port p and subcarrier spacing configuration u is called a resource element (RE), and one complex-valued symbol may be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l indicating the symbol position relative to a reference point in the time domain. RBs may be classified into common resource blocks (CRBs) and physical resource blocks (PRBs). The CRBs are numbered upwards from 0 in the frequency domain for subcarrier spacing configuration u . The center of subcarrier 0 of CRB 0 for a subcarrier spacing setting u coincides with 'point A', which is a common reference point for resource block grids. The PRBs for the subcarrier spacing setting u are defined in a bandwidth part (BWP) and are numbered from 0 to N ^size,u _BWP,i -1, where i is the number of the bandwidth part. The relationship between the common resource block n ^u _CRB and the physical resource block n _PRB in the bandwidth part i is as follows: n ^u _PRB = n ^u _CRB + N ^start,u _BWP,i , where N ^start,u _BWP,i is the common resource block where the bandwidth part starts relative to CRB 0. A BWP comprises a plurality of contiguous RBs in the frequency domain. For example, a BWP is a subset of contiguous CRBs defined for a given numerology u _i within BWP i on a given carrier. A carrier can contain up to N (e.g., 5) BWPs. A UE can be configured to have one or more BWPs on a given component carrier. Data communication is performed via the activated BWPs, and only a predetermined number (e.g., 1) of BWPs configured for the UE can be activated on the carrier.

For each BWP, the UE may be provided with at least one of the following parameters for the serving cell: i) subcarrier spacing, ii) cyclic prefix, iii) CRB N ^start _BWP = O carrier + RB start and the number of contiguous RBs N _{size BWP} = L _RB , and O _carrier provided by the RRC parameter offsetToCarrier for subcarrier spacing, provided by the RRC parameter locationAndBandwidth indicating offset RB _set and ^length L _RB as resource indicator value (RIV) with assumption that N ^start _BWP = 275; an _index within the set of DL BWPs or of UL BWPs; a set of BWP-common parameters and a set of BWP-specific parameters.

Virtual resource blocks (VRBs) are defined within a bandwidth part and numbered from 0 to N ^size,u _BWP,i -1, where i is the number of the bandwidth part. A UE may assume that VRBs are mapped to PRBs according to a mapping scheme indicated to the UE (e.g., non-interleaved or interleaved mapping). If no mapping scheme is indicated, the UE assumes non-interleaved mapping. In the case of non-interleaved VRB-to-PRB mapping, VRB n may be mapped to PRB n. In the case of interleaved VRB-to-PRB mapping, VRBs may be distributed and mapped to PRBs according to predefined rules.

Figure 5 illustrates an example of a physical downlink control channel (PDCCH) structure used in a 3GPP-based wireless communication system.

In 3GPP-based wireless communication systems, transmission of downlink control channels is defined by resource element groups (REGs) and/or control channel elements (CCEs).

In some scenarios (e.g., NR), a REG corresponds to 1 OFDM symbol in the time domain and 1 RB in the frequency domain. In other words, a REG is equivalent to 1 RB during 1 OFDM symbol.

CCE can mean the minimum unit for control channel transmission. That is, the minimum PDCCH size can correspond to 1 CCE. According to the aggregation level (AL) L, the BS can transmit one PDCCH by aggregating L CCEs. For example, in the case of AL 4, the PDCCH consists of 4 CCEs.

A set of radio resources on which PDCCHs can be located is called a control resource set (CORESET). A control resource set (CORESET), which is a set of time-frequency resources on which a UE can monitor PDCCHs, can be defined and/or configured. One or more CORESETs can be configured for a UE. In some implementations, a CORESET consists of a set of physical resource blocks (PRBs) with a time duration of 1, 2, or 3 OFDM symbols. The PRBs constituting the CORESET and the CORESET duration can be provided to the UE via higher layer (e.g., RRC) signaling. A set of PDCCH candidates within the configured CORESET(s) is monitored according to the corresponding search space sets. In this specification, monitoring imply decoding (so-called blind decoding) each PDCCH candidate according to the monitored DCI formats. The following are examples of DCI formats that a PDCCH can carry.

The set of PDCCH candidates monitored by the UE is defined in terms of PDCCH search space sets. The search space set can be a common search space (CSS) set or a UE-specific search space (USS) set. Each CORESET configuration is associated with one or more search space sets, and each search space set is associated with one CORESET configuration. For example, the search space set s can be determined based on the following parameters provided to the UE by the BS.

- controlResourceSetId : An identifier that identifies the CORESET p associated with the search space set s.

- monitoringSlotPeriodicityAndOffset : PDCCH monitoring periodicity of k _s slots and PDCCH monitoring offset of o _s slots to set slots for PDCCH monitoring.

- duration : The duration of T _s < k _s slots, which indicates the number of slots in which the search space set s exists.

- monitoringSymbolsWithinSlot : PDCCH monitoring pattern within a slot, indicating the first symbol(s) of the CORESET within the slot for PDCCH monitoring.

- nrofCandidates : Number of PDCCH candidates per CCE aggregation level.

- searchSpaceType : Indicates whether the search space set s is a CSS set or a USS set.

The parameter monitoringSymbolsWithinSlot represents, for example, the first symbol(s) for PDCCH monitoring within the slots configured for PDCCH monitoring (e.g., see parameters monitoringSlotPeriodicityAndOffset and duration ). For example, if monitoringSymbolsWithinSlot is 14-bit, the most significant (left) bit represents the first OFDM symbol within the slot, the second most significant (left) bit represents the second OFDM symbol within the slot, and so on, such that the bits of monitoringSymbolsWithinSlot can represent (respectively) the 14 OFDM symbols of the slot. For example, the bit(s) in monitoringSymbolsWithinSlot that are set to 1 identify the first symbol(s) of the CORESET within the slot.

In some scenarios, for a search space set s associated with a CORSET p, the CCE indices for the aggregation level L corresponding to the PDCCH candidate m _{s,n_CI} of the search space set in slot n ^u _s,f for the serving cell corresponding to the carrier aggregation field value n_CI can be given by:

; USS의 경우,

, Y_p,-1=n_RNTI≠0 (여기서, n_RNTI를 위해 사용되는 RNTI 값은 셀 무선 네트워크 임시 식별자(cell radio network temporary Identifier, C-RNTI)이다), p mod 3 = 0에 대해 A_p = 39827, p mod 3 = 1에 대해 A_p = 39829, p mod 3 = 2에 대해 A_p = 39839, 및 D = 65537; i = 0, ..., L-1; N_CCE,p는 CORESET p 내 그리고, 있다면, RB 세트당, 0부터 N_CCE,p - 1까지 번호 매겨진, CCE들의 개수이며; 동일 서빙 셀로부터 상기 서빙 셀의 스케줄링을 위한 경우(이 경우, n_CI = 0)를 제외하고 n_CI는 PDCCH 모니터되는 서빙 셀에 대해 크로스 반송파 스케줄링 설정에 의해 반송파 지시자 필드를 가지고 설정되면 반송파 지시자 필드 값이며; m^(L) _{s,n_CI} = 0, ..., M^(L) _{s,n_CI} - 1, 여기서 M^(L) _{s,n_CI}는 n_CI에 대응하는 서빙 셀에 대해 탐색 공간 세트 s의 집성 레벨 L에 대해 모니터하도록 설정된 PDCCH 후보들의 개수이고; 임의의(any) CSS의 경우, M^(L) _s,max = M^(L) _s,o; USS의 경우, M^(L) _s,max는 탐색 공간 세트 s의 CCE 집성 레벨 L에 대해 모든 설정된 n_CI 값들에 대해 M^(L) _{s,n_CI}의 최대치(maximum)이다.Here, for any CSS,

; For USS,

, Y _p,-1 = n _RNTI ≠0 (where the RNTI value used for n _RNTI is a cell radio network temporary Identifier (C-RNTI)), A _p = 39827 for p mod 3 = 0, A p = 39829 for p mod 3 = 1, A _p = 39839 for p mod 3 = 2, and D = 65537; i = 0, ..., L-1; N _CCE,p is the number of CCEs in _CORESET p and, if any, per RB set, numbered from 0 to N _CCE,p - 1; Except for the case of scheduling of the serving cell from the same serving cell (in this case, n_CI = 0), n_CI is a carrier indicator field value if it is set with a cross-carrier scheduling configuration for the serving cell being PDCCH monitored; m ^(L) _{s,n_CI} = 0, ..., M ^(L) _{s,n_CI} - 1, where M ^(L) _{s,n_CI} is the number of PDCCH candidates that are set to be monitored for the aggregation level L of the search space set s for the serving cell corresponding to n_CI; for any CSS, M ^(L) _s,max = M ^(L) _s,o ; for USS, M ^(L) _s,max is a maximum of M ^(L) _{s,n_CI} for all set n_CI values for the CCE aggregation level L of the search space set s.

Figure 6 illustrates mapping methods between control channel elements (CCEs) and resource element groups (REGs).

Within a CORESET, REGs and CCEs are numbered. The REGs within a CORESET, which consists of N ^CORESET _RB RBs in the frequency domain and N ^CORESET _symb symbols in the time domain, are numbered in increasing order in a time-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered RB within the CORESET. Multiple CORESETs may be configured for a UE, and for each CORESET, the CCE-to-REG mapping may be interleaved CCE-to-REG mapping or non-interleaved CCE-to-REG mapping. In some scenarios, the CCE-to-REG mapping may be described by the following REG bundles:

- REG bundle i is defined as REGs {iL,iL+1,...,iL+L-1}, where L is the REG bundle size, i=0,1,...,N ^CORESET _REG /L-1, and N ^CORESET _REG = N ^CORESET _RB *N ^CORESET _symb is the number of REGs in the CORESET,

- CCE j consists of REG bundles {f(6j/L), f(6j/L+1),...,f(6j/L + 6/L-1)}, where f(·) is an interleaver.

For non-interleaved CCE-to-REG mapping, L = 6 and f(x) = x. Referring to Fig. 6(a), for non-interleaved CCE-to-REG mapping, six REGs are grouped to form a REG bundle for a given CCE, and all REGs in a given CCE are consecutive, and one REG bundle is equivalent to one CCE.

For interleaving CCE-to-REG mapping, L∈{2,6} for N ^CORESET _symb = 1 and L∈{N ^CORESET _symb ,6} for N ^CORESET _symb ∈ {2,3}. The interleaver can be defined by

Here, R∈{2,3,6}. Referring to FIG. 6(b), for a given CCE, 2 or 3 or 6 consecutive REGs are grouped to form one REG bundle, and the REG bundles are interleaved within the CORESET. One REG bundle consists of 2 or 6 REGs for a CORESET with N ^CORESET _symb = 1, 2 or 6 REGs for a CORESET with N ^CORESET _symb = 2, and 3 or 6 REGs for a CORESET with N ^CORESET _symb = 3. The REG bundle size can be configured per CORESET. For a CORESET configured by higher layer signaling (e.g., RRC signaling): N ^CORESET _RBs and N ^CORESET _symbs can be provided to the UE by higher layer signaling (e.g., RRC signaling); Interleaved or non-interleaved mapping can be provided to the UE by higher layer signaling (e.g., RRC signaling) as CCE-to-REG mapping type; L can be provided to the UE by higher layer signaling (e.g., RRC signaling) for non-interleaved mapping; and if n _shift ∈ {0,1,...,274} is provided to the UE by higher layer signaling (e.g., RRC signaling) or not provided by higher layer signaling, then n _shift = N ^cell _ID , where N ^cell _ID is a cell-layer cell identifier determined by a synchronization signal of the cell.

Considering the rapidly increasing amount of communication, a method of utilizing shared spectrum, which is an unlicensed spectrum that is not licensed to a specific network operator and can be freely used by multiple network operators, has been discussed. Hereinafter, among 3GPP-based communication technologies, technologies applied to uplink communication and/or downlink communication between UE and BS in shared spectrum are described.

Unless otherwise stated, the following definitions apply to terms relating to shared spectrum in this specification:

- Channel: Consists of consecutive RBs on which a channel access process is performed in a shared spectrum, and may refer to a carrier or a part of a carrier.

- Channel access procedure (CAP): This refers to the process of evaluating channel availability based on sensing to determine whether other communication devices(s) are using the channel before signal transmission. When a BS or UE senses a channel during a sensing slot period, and the detected power is less than an energy detection threshold for at least a certain period of time within the sensing slot period, the sensing slot period is considered as an idle or free state, otherwise the sensing slot period is considered as a busy state. CAP may be referred to as LBT (Listen-Before-Talk).

- Channel occupancy: refers to the corresponding transmission(s) on the channel(s) by the BS/UE after the execution of CAP.

- Channel occupancy time (COT): refers to the total time that the BS/UE and any BS/UE(s) sharing the channel occupancy can perform transmission(s) on the channel after the BS/UE performs CAP. COT can be shared for transmissions between the BS and corresponding UE(s).

Since the shared spectrum is not dedicated to a specific network operator, the BS and UE may apply Listen-Before-Talk (LBT) before performing transmission on a cell configured with shared spectrum channel access. When LBT is applied, the transmitter listens/senses the channel to determine whether the channel is free or busy, and performs transmission only if the channel is deemed free. In other words, for shared spectrum, a communication device must determine whether the channel is occupied by other communication device(s) before transmitting a signal.

In a shared spectrum, the size of the time interval and/or the frequency occupied region of the signal/channel transmitted by the UE and/or the power spectral density (PSD) may be required to be above a certain level, respectively, with respect to channel occupancy. For example, a communication device may be required to perform transmission in the shared spectrum with the size of the time interval and/or the frequency occupied region of the signal/channel and/or with the PSD above a certain level. Considering such occupied channel bandwidth (OCB) and power spectral density regulations for the shared spectrum, a set of (equally spaced) non-contiguous RBs on the frequency may be defined as a resource unit used for physical channel/signal transmission. Hereinafter, such a set of non-contiguous RBs is called an interlaced RB, an RB interlace, or an interlace.

Figure 7 illustrates a resource block (RB) interlace. Referring to Figure 7, multiple interlaces of RBs can be defined in the frequency domain. An interlace m∈{0, 1, ..., M-1} can be composed of (common) RBs {m, M+m, 2M+m, 3M+m, ...}, where M represents the number of interlaced RBs. That is, each interlace can be composed of multiple non-contiguous RBs. In some implementations, M can be given as follows.

An interlaced RB n ^u _IRB,m ∈{0, 1, ...} within BWP i and interlace m and a CRB n ^u _CRB can be given by: n ^u _CRB = M*n ^u _IRB,m + N ^start,u _BWP,i + ((m - N ^start,u _BWP,i ) mod M).

A communication device (e.g., UE) can transmit a signal/channel using one or more interlaced RBs.

For example, in a 3GPP based system, the resource block assignment information in the DCI carried by the PDCCH informs the UE of a set of up to M interlace indices, and a set of up to N ^BWP _{RB-set, UL contiguous} RB sets (for DCI format 0_0 and for DCI format 0_1 monitored in ^a UE-specific search space). An RB set consists of a plurality of contiguous RBs. DCI format 0_0 and DCI format 0_1 are DCI formats used to schedule the PUSCH. In some implementations, an RB set may correspond to a frequency resource on which a channel access procedure (CAP) is individually performed in a shared spectrum. For operation with shared spectrum channel access, uplink transmission subcarriers are mapped to one or more RB interlaces.

In some scenarios, the UE may determine RB(s) corresponding to the intersection of i) the indicated interlace and ii) the indicated RB set(s) and, if any, the union of guard bands between the indicated RB set(s) as the frequency resource for PUSCH transmission.

Figure 8 illustrates an interlaced RB-based uplink resource allocation in a shared spectrum. Figure 8(a) illustrates a case where one RB set is indicated through resource allocation information for PUSCH, and Figure 8(b) illustrates a case where contiguous RB sets are indicated through resource allocation information for PUSCH.

Referring to Fig. 8(a), based on the resource allocation (RA) information for PUSCH indicating {interlace #2, RB set #1}, RBs belonging to interlace #2 in RB set #1 can be determined to be PUSCH resources. That is, RBs corresponding to the intersection of {interlace #2, RB set #1} can be determined as PUSCH resources. Referring to Fig. 8(b), based on the resource allocation information for PUSCH indicating {interlace #2, RB set #1/#2}, RBs belonging to interlace #2 in RB sets #1 and #2 can be determined to be PUSCH resources. In this case, a guard band (i.e., GB #1) between RB set #1 and RB set #2 can also be used as a PUSCH transmission resource. That is, in some implementations, RBs corresponding to the intersection of {interlace #2, RB set #1 + RB set #2 + GB #1} can be determined as PUSCH resources. In this case, the guard band (i.e., GB #0) that is not between RB set #1 and RB set #2 even if it is adjacent to RB sets #1 and #2 is not used as a PUSCH transmission resource.

For shared spectrum operation, multiple RB sets can be configured, and an RB set corresponds to approximately 20 MHz. In addition, interlaces can be configured for shared spectrum operation. For example, an RB set with a 15 kHz subcarrier spacing can include 10 interlaces, and each interlace corresponds to 10 RBs. As another example, an RB set with a 30 kHz subcarrier spacing can include 5 interlaces, and each interlace corresponds to 10 RBs. A guard band is configured between adjacent RB sets, so that some of the RBs on the shared spectrum cannot be used for transmission. Interlaced RB-based transmission has been applied to uplink transmission so far. However, since an increase in the number of UEs participating in communication causes an increase in not only uplink transmission volume but also downlink transmission volume, it is desirable to allow interlaced RB-based transmission for downlink control/data transmission as well. When interlaced RB-based transmission is applied to downlink, especially when interlaced RB-based transmission is applied to PDCCH transmission, it is difficult to apply the PDCCH structure (hereinafter, REG-based PDCCH) described in FIGS. 5 and 6 as is. This is because according to the PDCCH structure described in FIGS. 5 and 6, since one CCE is composed of six RBs, it is difficult to align the number of RBs per interlace. In addition, in the case of the interleaved PDCCH structure, the interleaving space is not aligned with the interlace. In addition, since some RBs cannot be used on a shared spectrum, when a CORESET is configured on a shared spectrum, some CCEs within the CORESET may not be used for PDCCH transmission.

As the types of services that wireless communication systems must support are diversifying and traffic is rapidly increasing, the utilization of shared spectrum is becoming increasingly important. A method for efficiently transmitting PDCCH on shared spectrum supporting interlace-based transmission is required. Below, some implementations of this specification regarding PDCCH structure are described.

FIGS. 9 and 10 are diagrams illustrating the basic concept of an interlace-based PDCCH structure according to some implementations of the present specification.

In some implementations of this specification, for a cell or BWP configured for interlaced RB-based transmission (or interlaced RB-based resource allocation) or for a cell or BWP within a shared spectrum, the PDCCH structure may be defined/configured as follows.

- A CORESET consists of N ^CORESET _RB-set (>=1) RB sets in the frequency domain, and one CCE consists of one interlace (including DM-RS) within an OFDM symbol within the RB set. A CORESET may consist of N ^CORESET _symb OFDM symbols in the time domain, similarly to the non-shared spectrum. N ^CORESET _RB-set and N ^CORESET _symb may be predefined, or configured by the BS to the UE via higher layer signaling (RRC signaling). In some implementations, it may further be considered that one CCE consists of 0.5 interlace. - In some implementations, CCEs in a CORESET may be numbered in a frequency-first manner (hereinafter, frequency-first CCE indexing or frequency-first CCE numbering). For example, frequency-first interlace-to-CCE mapping may be applied. FIG. 9 illustrates examples of transmission of PDCCHs according to aggregation level (AL) in a situation where CCEs are numbered in frequency-first order. Referring to FIG. 9(b), one PDCCH (e.g., PDCCH#1) can be transmitted using CCEs of interlace #0 and CCEs of interlace #1 within an RB set during the 1 ^st OFDM symbol of a CORESET. Similarly, PDCCH#2 can be transmitted using CCEs of interlace #2 and CCEs of interlace #3 within an RB set during the 2 ^nd OFDM symbol of the CORESET. As a result, PDCCH#1 and PDCCH#2 can be transmitted in different OFDM symbols, respectively. In some implementations, if a CORESET consists of multiple RB sets in the frequency domain, the frequency-first CCE indexing can be performed across the multiple RB sets (e.g., see CCE indices of FIG. 14). In this case, CCEs on different RB sets are assigned different CCE indices. Alternatively, frequency-first indexing may be performed per RB set. For example, frequency-first CCE indexing may be performed starting from the RB set with the lowest index for N ^CORESET _symb OFDM symbol(s) in an RB set, and then frequency-first CCE indexing may be performed for the starting CCE of the next RB set starting from the CCE index following the largest CCE index assigned to the RB set, such that the CCE indices in the CORESET are assigned (e.g., see CCE indices in FIG. 15). Alternatively, in some implementations, frequency-first CCE indexing may be performed in a way that CCE indices are initialized per RB set (e.g., see CCE indices in FIG. 16). In this case, CCEs belonging to different RB sets may have the same CCE index. When frequency indexing is reset per RB set, CCEs belonging to different RB sets are considered as different CCEs even if they have the same CCE index.

- In some implementations, CCEs in a CORESET may be numbered in a time-first manner (hereinafter, referred to as time-first CCE indexing or time-first CCE numbering). For example, time-first interlace-to-CCE mapping may be applied. Fig. 10 illustrates an example of transmission of PDCCHs according to AL in a situation where CCEs are numbered in a time-first manner. As an example, in case of AL=2 and time-first CCE mapping, referring to Fig. 10(b), in a CORESET with N ^CORESET _symb =2, each PDCCH may be transmitted using both the 1 ^st OFDM symbol and the 2nd OFDM symbol. In some implementations, when a CORESET consists of multiple RB sets in the frequency domain, time-first CCE indexing may be performed across the multiple RB sets (e.g., see CCE indices in Fig. 17). In this case, CCEs on different RB sets may be assigned different CCE indices. Alternatively, in some implementations, time-first indexing may be performed in a way that the CCE index is initialized for each RB set. In this case, CCEs belonging to different RB sets may have the same CCE index (e.g., see CCE indices in Fig. 18). If frequency-indexing is reset for each RB set, CCEs belonging to different RB sets are considered as different CCEs even if they have the same CCE index.

- In some implementations, aggregation level L may be defined as L interlaces. For example, for aggregation level L, one PDCCH may be transmitted across L interlaces. If one CCE is defined as equal to one interlace in an OFDM symbol, a PDCCH of aggregation level L may be expressed as consisting of L CCE(s), as illustrated in FIGS. 9 and 10.

- Alternatively, in some implementations, the aggregation level L can be defined as K*L interlaces, where K is the number of interlaces per CCE.

- The number of PDCCH candidates per search space can be configured.

- Partial CCEs can be used for high aggregation levels.

According to some implementations of this specification, if CORESET is defined/set on an interlace basis, PDCCH can be transmitted on an interlace basis, thus increasing resource utilization efficiency.

Figure 11 illustrates examples of interlace-to-CCE mapping for interlace-based PDCCH according to some implementations of the present specification. In the examples of Figure 11, a CORESET with N ^CORESET _RB-set = 1 and N ^CORESET _symb = 2 is assumed.

Referring to Fig. 11(a), in some implementations, frequency-first interlace-to-CCE mapping may be applied for interlace-based PDCCH. When interlace-to-CCE mapping is performed in a frequency-first manner, since there is a high possibility that a PDCCH will be transmitted on consecutive interlaces within one symbol, a UE may perform an early termination operation during PDCCH blind decoding, thereby achieving UE power saving.

Referring to Fig. 11(b), in some implementations, time-first interlace-to-CCE mapping may be applied for interlace-based PDCCH. When interlace-to-CCE mapping is performed in a time-first manner, PDCCH reception quality may be improved since PDCCH is more likely to be transmitted across multiple symbols of a CORESET.

Figures 12 and 13 illustrate examples of control channel element (CCE) aggregation according to some implementations of the present specification.

In the example of Fig. 12(a), frequency-first interlace-to-CCE mapping and mapping of PDCCH to contiguous or consecutive CCEs are assumed. Referring to Fig. 12(a), in some implementations, CCEs may be aggregated first in the frequency domain. For example, when AL = 4, a PDCCH may be composed of four consecutive CCEs in the frequency domain (CCE#0 to CCE#3 in the case of Fig. 12(a)). As another example, when AL = 8, a PDCCH may be composed of eight consecutive CCEs (CCE#0 to CCE#7 in the case of Fig. 12(a)).

In the example of Fig. 12(b), time-first interlace-to-CCE mapping and mapping of PDCCH to non-contiguous or non-consecutive CCEs are assumed. Referring to Fig. 12(b), in some implementations, CCEs may be aggregated first in the time domain. For example, when AL = 4, in a CORESET with N ^CORESET _symb = 2, four CCEs (CCE#0, CCE#1, CCE#5 and CCE#6 in Fig. 12(b)), each consisting of two consecutive interlaces in the frequency domain and two OFDM symbols in the time domain, may be used for transmission of the PDCCH. As another example, when AL = 8, in a CORESET with N ^CORESET _symb = 2, eight CCEs (CCE#0, CCE#5, CCE#1, CCE#6, CCE#2, CCE#7, CCE#3, and CCE#8 in Fig. 12(b)) consisting of four consecutive interlaces in the frequency domain and two OFDM symbols in the time domain can be used for transmission of the PDCCH.

In the example of Fig. 13(a), time-first interlace-to-CCE mapping and mapping of PDCCH to non-contiguous or non-consecutive CCEs are assumed. Referring to Fig. 13(a), in some implementations, CCEs may be aggregated first in the frequency domain. For example, when AL = 4, a PDCCH may be composed of four consecutive CCEs in the frequency domain (CCE#0, CCE#2, CCE#4, and CCE#6 in the case of Fig. 13(a)). As another example, when AL = 8, a PDCCH may be composed of eight CCEs (CCE#0, CCE#2, CCE#4, CCE#6, CCE#8, CCE#1, CCE#3, and CCE#5 in the case of Fig. 13(a)).

In the example of Fig. 13(b), time-first interlace-to-CCE mapping and mapping of PDCCH to contiguous or consecutive CCEs are assumed. Referring to Fig. 13(b), in some implementations, CCEs may be aggregated first in the time domain. For example, when AL = 4, in a CORESET with N ^CORESET _symb = 2, four CCEs (CCE#0 to CCE#3 in Fig. 13(b)), each consisting of two consecutive interlaces in the frequency domain and two OFDM symbols in the time domain, may be used for transmission of the PDCCH. ^As another example, when AL = 8, 8 CCEs (CCE# ₀ to CCE#7 in Fig. 12(b)) consisting of 4 consecutive interlaces in the frequency domain and 2 OFDM symbols in the time domain can be used for transmission of the PDCCH in a CORESET with N CORESET symb = 2.

In some implementations of this specification, the frequency-first PDCCH-to-CCE mapping (FIG. 12(a) or FIG. 13(a)) and the time-first PDCCH-to-CCE mapping (FIG. 12(b) or FIG. 13(b)) may be used together. For example, when AL=L, L CCEs in a CORESET may be selected and mapped to the PDCCH based on a (pre-)configured or (pre-)defined pattern. Alternatively, in some implementations of this specification, it may be specified that the frequency-first PDCCH-to-CCE mapping is applied for the frequency-first interlace-to-CCE mapping, and the time-first PDCCH-to-CCE mapping is applied for the time-first interlace-to-CCE mapping.

In some implementations of this specification, it may be predefined between the BS and the UE which interlace-to-CCE mapping scheme is applied for a cell or BWP where interlaced RB based transmission (or interlaced RB based resource allocation) is configured, or for a cell or BWP in a shared spectrum. Alternatively, in some implementations of this specification, it may be provided to the UE by the BS via PBCH on the cell, etc., which interlace-to-CCE mapping scheme is applied for a cell or BWP where interlaced RB based transmission (or interlaced RB based resource allocation) is configured, or for a cell or BWP in a shared spectrum. A guard band may be configured between RB sets on the shared spectrum. Since interferences between transmissions occurring on the RB sets may exist in the guard band, it is not recommended to be used for control channel transmission. Due to the guard band between RB sets, there may be partial interlace(s) in which the number of RBs included in an interlace is less than the number of RBs in another interlace. In some implementations of this specification, partial interlacing may be handled as follows:

> Alt 1. Partial interlaces are excluded from the CCE count. In other words, partial interlaces are not used for PDCCH transmission. In this case, the partial interlaces may not be assigned a CCE index. Since partial interlaces are not treated as CCEs according to Alt 1, when partial CCEs are not used for PDCCH transmission, the PDCCH reception quality at the UE can be maintained evenly.

> Alt 2. Partial interlaces are included in the CCE count. In other words, partial interlaces can also be used for PDCCH transmission. In this case, a CCE index can also be assigned to the partial interlace. Since partial interlaces are treated as CCEs according to Alt 2, when partial CCEs are used for PDCCH transmission, the amount of unavailable resources in the frequency domain is reduced, so that resource utilization efficiency can be increased.

> Alt 3. Partial interlace can be used for PDCCH transmission only for higher aggregation levels (e.g., AL > 4). For high aggregation levels, even if partial CCE is used for PDCCH transmission, PDCCH reception quality can be improved by other full CCEs, so the degradation of PDCCH reception quality by partial CCE can be less compared to low aggregation levels.

FIGS. 14 to 18 illustrate examples of transmitting a PDCCH across multiple resource block sets according to some implementations of the present specification. In the examples of FIGS. 14 to 18, it is assumed that a CORESET is configured across RB set 0 and RB set 1 in the frequency domain, and that one CCE is equivalent to one interlace during an OFDM symbol within an RB set. In the examples of FIG. 14, frequency-first CCE indexing across RB sets is assumed. In the examples of FIG. 15, frequency-first CCE indexing per RB set is assumed. In the examples of FIG. 16, frequency-first CCE indexing that initializes the CCE index per RB set, i.e., starts with the same CCE index for each RB set, is assumed. In the case of frequency-first CCE indexing that initializes the CCE index per RB set, CCEs with the same CCE index belonging to different RB sets are treated as different CCEs. In the examples of Fig. 17, time-first CCE indexing across RB sets is assumed. In the examples of Fig. 18, time-first CCE indexing that initializes the CCE index per RB set is assumed.

Multiple RB sets can be configured for shared spectrum operation, and guard bands can be configured between adjacent RB sets. Hereinafter, implementations of the present specification for mapping PDCCH when multiple RB sets are configured within a shared spectrum or within one BWP are described.

Referring to FIGS. 14(a), 15(a), 16(a), 17(a), and 18(a), in some implementations of the present specification, a PDCCH candidate is mapped within an RB set. Referring to FIGS. 14(a), 15(a), 17(a), and 18(a), for AL=4, a PDCCH candidate may be composed of, for example, four CCEs, CCE#0 to CCE#3, within RB set 0. When a PDCCH candidate is mapped within an RB set, power consumption of a UE may be reduced when monitoring a PDCCH since a PDCCH transmission bandwidth does not exceed the bandwidth of the RB set. In some implementations, a search space may be defined per RB set. Alternatively, in some implementations, a search space may be defined over multiple RB sets.

Referring to FIG. 14(b), FIG. 15(b), FIG. 16(b), FIG. 17(b), and FIG. 18(b), in some implementations of the present specification, a PDCCH candidate is mapped across RB sets. Referring to FIG. 14(b), for AL=4, a PDCCH candidate may consist of, for example, four CCEs, namely CCE#0 and CCE#1 in RB set 0 and CCE#5 and CCE#6 in RB set 1. Referring to FIG. 15(b), for AL=4, a PDCCH candidate may consist of, for example, four CCEs, namely CCE#0 and CCE#1 in RB set 0 and CCE#10 and CCE#11 in RB set 1. Referring to FIG. 16(b), for AL=4, a PDCH candidate may be configured with, for example, four CCEs, CCE#0 and CCE#1 in RB set 0 and CCE#0 and CCE#1 in RB set 1. Referring to FIG. 17(b), for AL=4, a PDCH candidate may be configured with, for example, four CCEs, CCE#0 and CCE#1 in RB set 0 and CCE#5 and CCE#15 in RB set 1. Referring to FIG. 18(b), for AL=4, a PDCH candidate may be configured with, for example, four CCEs, CCE#0 and CCE#1 in RB set 0 and CCE#0 and CCE#1 in RB set 1. When PDCCH candidates are mapped across RB sets, frequency diversity gain can be obtained. In some implementations, mapping PDCCH candidates across multiple RB sets may be supported subject to higher aggregation levels (e.g., AL > 8).

FIG. 19 illustrates part of a process by which a user equipment (UE) receives a downlink channel according to some implementations of the present specification.

The UE can receive a configuration related to a CORESET to which an interlace-based PDCCH structure is applied (S1901). The CORESET-related configuration may include, according to some implementations of the present specification, information about RB set(s) in the frequency domain that constitute the CORESET and information about the number of OFDM symbols in the time domain.

The UE may monitor PDCCH on an interlace basis according to the CORESET-related settings (S1903). For example, the UE may perform PDCCH monitoring assuming that each PDCCH candidate in the search space associated with the CORESET is configured on an interlace basis according to some implementations of the present specification described above.

When the above UE detects a DCI format through PDCCH monitoring, it can perform operations according to the DCI format.

Figure 20 illustrates part of a process by which a base station (BS) transmits a downlink channel according to some implementations of the present specification.

The BS can transmit a configuration regarding a CORESET to which an interlace-based PDCCH structure is applied (S2001). The CORESET-related configuration may be an RRC configuration provided by the BS to the UE. The CORESET-related configuration may include information regarding RB sets in the frequency domain that constitute the CORESET and information regarding the number of OFDM symbols in the time domain, according to some implementations of the present specification.

The BS may perform PDCCH transmission on an interlace basis according to the CORESET-related settings (S2003). The BS may transmit a PDCCH carrying a DCI format within a search space associated with a CORESET according to the CORESET-related settings. PDCCH monitoring may be performed assuming that each PDCCH candidate monitored by the UE is configured on an interlace basis according to some implementations of the present specification described above.

The above BS may perform downlink transmission(s) and/or uplink reception(s) assuming that the UE that detected the DCI format will perform operations according to the DCI format.

Figure 21 illustrates a PDCCH transmission/monitoring flow according to some implementations of the present specification.

Interlace-based PDCCH according to some implementations of the above-mentioned specification may be applied under certain conditions. The certain conditions may include, for example:

> PDCCH transmission or PDCCH monitoring is performed in shared spectrum;

> PDCCH transmission hook is performed in a cell or BWP where PDCCH monitoring is set up for interlaced-RB based transmission;

> PDCCH transmission or PDCCH monitoring is performed in a cell or BWP where the UE is configured to use interlace-RB based frequency domain resource allocation for PUSCH or PDSCH; and/or

> PDCCH transmission or PDCCH monitoring is performed in the search space associated with the CORESET for which interlace-based transmission is configured.

In some implementations, information about whether a cell or BWP on which a PDCCH transmission or PDCCH monitoring is performed belongs to a shared spectrum may be provided to UEs via a PBCH within a synchronization signal block (SSB) transmitted on that cell or BWP.

In some implementations, interlace-RB based transmission for a cell or BWP where PDCCH transmission or PDCCH monitoring is performed may be provided to the UE via RRC signaling. In some implementations, interlace-RB based frequency domain resource allocation for PUSCH or PDSCH for a cell or BWP where PDCCH transmission or PDCCH monitoring is performed may be provided to the UE via RRC signaling.

In some implementations, the RRC configuration for a CORESET may include a configuration regarding whether that CORESET is interlace-based.

In some implementations of this specification, if the above specific condition is satisfied (S2103, Yes), an interlace-based PDCCH according to some implementations of this specification is applied for PDCCH transmission or PDCCH monitoring (S2105a), otherwise (S2103, No), a REG-based PDCCH described in FIG. 5 or FIG. 6 may be applied for PDCCH transmission or PDCCH monitoring (S2105b).

A UE may perform operations according to some implementations of the present disclosure in connection with receiving a PDCCH. The UE may include at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for the UE may include at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer-readable (non-transitory) storage medium may store at least one computer program comprising instructions that, when executed by the at least one processor, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer program or computer program product may be recorded on at least one computer-readable (non-transitory) storage medium and may contain instructions that, when executed, cause (at least one processor) to perform operations according to some implementations of the present specification.

A BS may perform operations according to some implementations of the present disclosure in connection with transmitting a PDCCH. The BS may include at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for the BS may include at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer-readable (non-transitory) storage medium may store at least one computer program comprising instructions that, when executed by the at least one processor, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer program or computer program product may be recorded on at least one computer-readable (non-transitory) storage medium and may contain instructions that, when executed, cause (at least one processor) to perform operations according to some implementations of the present specification.

In the UE, the processing device, the computer-readable (non-transitory) storage medium, and/or the computer program product, the operations may include: receiving a configuration regarding CORESET; and monitoring a set of PDCCH candidates based on the configuration; and detecting a DCI format within the set of PDCCH candidates. In the BS, the processing device, the computer-readable (non-transitory) storage medium, and/or the computer program product, the operations may include: transmitting a configuration regarding CORESET; and transmitting a DCI format within the set of PDCCH candidates based on the configuration.

In some implementations, the CORESET may consist of N ^CORESET _RB-set RB sets, each of which comprises a plurality of contiguous resource blocks (RBs) in the frequency domain, and N ^CORESET _symb OFDM symbols in the time domain. In some implementations, each PDCCH candidate in the CORESET may consist of one or more CCEs. In some implementations, each CCE in the CORESET may be identical to one interlace during an OFDM symbol in the RB set for the CORESET.

In some implementations, each of said one or more interlaces may consist of multiple non-contiguous RBs.

In some implementations, the CCEs within the CORESET may be numbered in increasing order in a frequency-first manner, starting with 0 for the first OFDM symbol and the lowest-numbered interlace within the CORESET.

In some implementations, the CCEs within the CORESET may be numbered in increasing order in a time-first manner, starting with 0 for the first OFDM symbol and the lowest-numbered interlace within the CORESET.

In some implementations, the configuration may include the number of PDCCH candidates per aggregation level L. Each PDCCH candidate of aggregation level L may include L CCEs in the COREST.

In some implementations, each PDCCH candidate within the CORESET may consist of CCEs from one RB set.

In some implementations, each PDCCH candidate within the CORESET may consist of CCEs from multiple RB sets.

In some implementations, two adjacent RB sets among the N ^CORESET _RB-set RB sets in the CORESET may have a guard band between the two adjacent RB sets.

In some implementations, each CCE within the CORESET may not be mapped to an interlace where some of the RBs fall within the guard band.

In some implementations, the CORESET may include CCEs mapped to interlaces where some of the RBs fall within the guard band.

As described above, the examples of the present disclosure are provided to enable a person skilled in the art to implement and practice the present disclosure. While the examples of the present disclosure have been described above with reference to the examples of the present disclosure, those skilled in the art will appreciate that various modifications and variations may be made to the examples of the present disclosure. Accordingly, the present disclosure is not intended to be limited to the examples set forth herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Implementations of this specification can be used in wireless communication systems, BSs, user equipment, or other equipment.

Claims (21)

When a user device receives a downlink channel in a wireless communication system, Receive settings regarding a control resource set (CORESET); and Monitoring a set of physical downlink control channel (PDCCH) candidates based on the above settings; and Including detecting a downlink control information (DCI) format within the set of PDCCH candidates, The above CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes multiple consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain. Each PDCCH candidate in the above CORESET consists of one or more control channel elements (CCEs). Each CCE within the CORESET is equivalent to one interlace during an OFDM symbol within the RB set for the CORESET. How to receive a downlink channel. In the first paragraph, Each of said one or more interlaces is composed of a plurality of non-contiguous RBs, How to receive a downlink channel. In the first paragraph, The CCEs within the CORESET are numbered in increasing order in a frequency-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered interlace within the CORESET. How to receive a downlink channel. In the first paragraph, The CCEs within the above CORESET are numbered in increasing order in a time-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered interlace within the above CORESET. How to receive a downlink channel. In the first paragraph, The above setting includes the number of PDCCH candidates per aggregation level L. Each PDCCH candidate of aggregation level L includes L CCEs in the COREST. How to receive a downlink channel. In the first paragraph, Each PDCCH candidate in the above CORESET consists of CCEs from one RB set. How to receive a downlink channel. In the first paragraph, Each PDCCH candidate in the above CORESET is composed of CCEs from multiple RB sets. How to receive a downlink channel. In the first paragraph, Among the N ^CORESET _RB-set RB sets in the CORESET, two adjacent RB sets have a guard band between the two adjacent RB sets, Each CCE within the above CORESET is not mapped to an interlace where some of the RBs are included in the guard band. How to receive a downlink channel. In the first paragraph, Among the N ^CORESET _RB-set RB sets in the CORESET, two adjacent RB sets have a guard band between the two adjacent RB sets, The above CORESET includes CCEs mapped to interlaces among some of the RBs included in the guard band. How to receive a downlink channel. When a user device receives a downlink channel in a wireless communication system, At least one transceiver; at least one processor; and At least one memory operably connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations, said operations comprising: Receive settings regarding a control resource set (CORESET); and Monitoring a set of physical downlink control channel (PDCCH) candidates based on the above settings; and Including detecting a downlink control information (DCI) format within the set of PDCCH candidates, The above CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes multiple consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain. Each PDCCH candidate in the above CORESET consists of one or more control channel elements (CCEs). Each CCE within the CORESET is equivalent to one interlace during an OFDM symbol within the RB set for the CORESET. User device. A computer-readable non-transitory storage medium comprising at least one computer program that causes at least one processor to perform operations, the operations comprising: Receive settings regarding a control resource set (CORESET); and Monitoring a set of physical downlink control channel (PDCCH) candidates based on the above settings; and Including detecting a downlink control information (DCI) format within the set of PDCCH candidates, The above CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes multiple consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain. Each PDCCH candidate in the above CORESET consists of one or more control channel elements (CCEs). Each CCE within the CORESET is equivalent to one interlace during an OFDM symbol within the RB set for the CORESET. Storage medium. When a base station transmits a downlink channel in a wireless communication system, Transmitting settings regarding the control resource set (CORESET); and It includes transmitting a downlink control information (DCI) format within a set of physical downlink control channel (PDCCH) candidates based on the above settings, The above CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes multiple consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain. Each PDCCH candidate in the above CORESET consists of one or more control channel elements (CCEs). Each CCE within the CORESET is equivalent to one interlace during an OFDM symbol within the RB set for the CORESET. Downlink channel transmission method. In Article 12, Each of said one or more interlaces is composed of a plurality of non-contiguous RBs, Downlink channel transmission method. In Article 12, The CCEs within the above CORESET are numbered in increasing order in a frequency-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered interlace within the above CORESET. Downlink channel transmission method. In Article 12, The CCEs within the above CORESET are numbered in increasing order in a time-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered interlace within the CORESET. Downlink channel transmission method. In Article 12, The above setting includes the number of PDCCH candidates per aggregation level L. Each PDCCH candidate of aggregation level L includes L CCEs in the COREST. Downlink channel transmission method. In Article 12, Each PDCCH candidate in the above CORESET consists of CCEs from one RB set. Downlink channel transmission method. In Article 12, Each PDCCH candidate in the above CORESET is composed of CCEs from multiple RB sets. Downlink channel transmission method. In Article 12, Among the N ^CORESET _RB-set RB sets in the CORESET, two adjacent RB sets have a guard band between the two adjacent RB sets, Each CCE within the above CORESET is not mapped to an interlace where some of the RBs are included in the guard band. Downlink channel transmission method. In Article 12, Among the N ^CORESET _RB-set RB sets in the CORESET, two adjacent RB sets have a guard band between the two adjacent RB sets, The above CORESET includes CCEs mapped to interlaces among some of the RBs included in the guard band. Downlink channel transmission method. When a base station transmits a downlink channel in a wireless communication system, At least one transceiver; at least one processor; and At least one memory operably connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations, said operations comprising: Transmitting settings regarding the control resource set (CORESET); and It includes transmitting a downlink control information (DCI) format within a set of physical downlink control channel (PDCCH) candidates based on the above settings, The above CORESET is composed of N ^CORESET _RB-set RB sets, each of which includes multiple consecutive resource blocks (RBs) in the frequency domain, and N ^CORESET _symb orthogonal frequency division multiplexing (OFDM) symbols in the time domain. Each PDCCH candidate in the above CORESET consists of one or more control channel elements (CCEs). Each CCE within the CORESET is equivalent to one interlace during an OFDM symbol within the RB set for the CORESET. Base station.

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