Method for transmitting physical downlink control channel in wireless communication system and apparatus therefor

Abstract

A method performed by a terminal for receiving a physical downlink control channel (PDCCH) in a wireless communication system includes the following steps: receiving configuration information about a first control resource set (CORESET) from a base station; receiving configuration information about a second CORESET from the base station; receiving a first PDCCH transmitted on the first CORESET from the base station; and receiving a second PDCCH transmitted on the second CORESET from the base station.

Description

[0001] This application is a divisional application of patent application No. 202180055033.4 (International Application No. PCT / KR2021 / 009291), filed on March 7, 2023, with an international application date of July 19, 2021, entitled "Method and Apparatus for Transmitting a Physical Downlink Control Channel in a Wireless Communication System". Technical Field

[0002] This specification relates to a wireless communication system, and more specifically, to a method and apparatus for transmitting a physical downlink control channel. Background Technology

[0003] Following the commercialization of fourth-generation (4G) communication systems, efforts are underway to develop new fifth-generation (5G) communication systems to meet the increasing demand for wireless data services. 5G communication systems are also referred to as post-4G network communication systems, post-LTE systems, or new radio (NR) systems. To achieve high data transmission rates, 5G communication systems include systems operating in millimeter-wave (mmWave) frequency bands of 6 GHz or higher, and systems operating in frequency bands of 6 GHz or lower are also considered to ensure coverage. The implementation methods in base stations and terminals are being considered.

[0004] The 3GPP (3rd Generation Partnership Project) NR system improves network spectral efficiency and enables communication providers to offer more data and voice services on a given bandwidth. Therefore, the 3GPP NR system is designed to meet the demand for high-speed data and media transmission in addition to supporting a large volume of voice traffic. The advantages of the NR system include higher throughput and lower latency on the same platform, support for Frequency Division Duplex (FDD) and Time Division Duplex (TDD), and lower operating costs due to the enhanced end-user environment and simpler architecture. For more efficient data processing, the NR system's dynamic TDD can use methods to change the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be used in the uplink and downlink based on the data traffic direction of the cell's users. For example, when downlink traffic in a cell is greater than uplink traffic, the base station can allocate multiple downlink OFDM symbols to time slots (or subframes). Information regarding the time slot configuration should be sent to the terminal.

[0005] To mitigate path loss and increase transmission distance in the mmWave band, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, hybrid beamforming combining analog and digital beamforming, and massive MIMO technologies are discussed in 5G communication systems. Furthermore, for network improvements, technologies related to evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, wireless backhaul, non-terrestrial network communication (NTN), mobile networks, cooperative communication, coordinated multipoint (CoMP), and interference cancellation are being developed in 5G communication systems. Additionally, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) are being developed as advanced coding and modulation (ACM) schemes, while filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) are being developed as advanced connectivity technologies.

[0006] Simultaneously, within the human-centric network of information generation and consumption, the Internet has evolved into the Internet of Things (IoT) network, which exchanges information between distributed components such as objects. The Internet of Everything (IoE) technology, combining IoT with big data processing through connections to cloud servers, is also emerging. Realizing IoT requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology. This has led to the research in recent years into technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) to connect objects. In the IoT environment, intelligent Internet of Things (IT) services can be provided, collecting and analyzing data generated from connected objects to create new value in human life. Through the integration and hybridization of existing information technology (IT) with various industries, IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0007] Therefore, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) are implemented using techniques such as beamforming, MIMO, and array antennas. The application of cloud RAN, as a big data processing technology, is an example of the convergence of 5G and IoT technologies. Typically, mobile communication systems are developed to provide voice services while ensuring user activity.

[0008] However, mobile communication systems are not only expanding their voice services but also their data services, and have now evolved to the point of providing high-speed data services. However, due to resource shortages and users' demands for high-speed services, more advanced mobile communication systems are needed within the current mobile communication systems providing services. Summary of the Invention

[0009] Technical issues

[0010] This specification is intended to provide a method and apparatus for transmitting a physical downlink channel in a wireless communication system.

[0011] Technical solution

[0012] This specification provides a method for transmitting a physical downlink channel in a wireless communication system.

[0013] This specification relates to a method for receiving a physical downlink control channel (PDCCH) in a wireless communication system, the method being performed by a terminal and comprising: receiving configuration information about a first control resource set (CORESET) from a base station; receiving configuration information about a second CORESET from the base station; receiving a first PDCCH transmitted on the first CORESET from the base station; and receiving a second PDCCH transmitted on the second CORESET from the base station, wherein the first PDCCH and the second PDCCH are each repeatedly transmitted from the base station, and the first downlink control information (DCI) included in the first PDCCH and the second DCI included in the second PDCCH are identical to each other.

[0014] Furthermore, in this specification, the method performed by the terminal further includes: receiving configuration information about a first search space from a base station; and receiving configuration information about a second search space from a base station, wherein the first search space is associated with a first CORESET, and the second search space is associated with a second CORESET, the first search space and the second search space are resources in different time domains, and the first PDCCH is received in the first search space, and the second PDCCH is received in the second search space.

[0015] Furthermore, in this specification, the method performed by the terminal further includes: sending HARQ-ACK information to the base station regarding one of the first PDCCH and the second PDCCH, wherein the HARQ-ACK information corresponds to HARQ-ACK information of the PDCCH sent on the search space of the lower index of the first search space and the second search space.

[0016] Furthermore, in this specification, the method performed by the terminal further includes: receiving a third PDCCH from the base station in a third search space; and sending HARQ-ACK information to the base station regarding one of the first PDCCH, the second PDCCH, and the third PDCCH, wherein the third PDCCH includes a third DCI different from the first DCI and the second DCI, and when the third search space overlaps with one of the first search space and the second search space, the HARQ-ACK information is HARQ-ACK information regarding the PDCCH sent in the search space with the lowest index among the indices of the overlapping search spaces.

[0017] Additionally, in this specification, a terminal for receiving a Physical Downlink Control Channel (PDCCH) in a wireless communication system includes: a transceiver; and a processor configured to control the transceiver, wherein the processor is configured to: receive configuration information about a first control resource set (CORESET) from a base station; receive configuration information about a second CORESET from the base station; receive a first PDCCH transmitted on the first CORESET from the base station; and receive a second PDCCH transmitted on the second CORESET from the base station, wherein the first PDCCH and the second PDCCH are each repeatedly transmitted from the base station, and the first downlink control information (DCI) included in the first PDCCH and the second DCI included in the second PDCCH are identical to each other.

[0018] Additionally, in this specification, the processor is configured to: receive configuration information about a first search space from a base station; and receive configuration information about a second search space from a base station, wherein the first search space is associated with a first CORESET, and the second search space is associated with a second CORESET, the first search space and the second search space are resources in different time domains, and the first PDCCH is received in the first search space, and the second PDCCH is received in the second search space.

[0019] In addition, in this specification, the first PDCCH and the second PDCCH are configured with the same polymerization level (AL).

[0020] In addition, in this specification, the first CORESET and the second CORESET are resources in different frequency domains.

[0021] In addition, in this specification, the first CORESET and the second CORESET are resources in the same time-frequency domain.

[0022] In addition, in this specification, the first PDCCH and the second PDCCH are included in the same time slot and are repeatedly transmitted.

[0023] In addition, in this specification, the first PDCCH and the second PDCCH are repeatedly transmitted in different time slots.

[0024] In addition, in this specification, the first DCI and the second DCI are each decoded independently.

[0025] In addition, in this specification, the first DCI and the second DCI are combined with each other and decoded.

[0026] In addition, in this specification, the configuration information for the first search space includes information about the period of the first search space, and the configuration information for the second search space includes information about the period of the second search space, and the periods of the first search space and the second search space are the same as each other.

[0027] In addition, in this specification, the types of the first search space and the second search space are the same as each other, and the types of the first search space and the second search space are one of the common search space and the UE-specific search space.

[0028] Additionally, this specification relates to a method for transmitting a physical downlink control channel (PDCCH) in a wireless communication system, the method being performed by a base station and comprising: transmitting configuration information about a first control resource set (CORESET) to a terminal; transmitting configuration information about a second CORESET to the terminal; transmitting a first PDCCH to the terminal on the first CORESET; and transmitting a second PDCCH to the terminal on the second CORESET, wherein the first PDCCH and the second PDCCH are each repeatedly transmitted to the terminal, and the first downlink control information (DCI) included in the first PDCCH and the second DCI included in the second PDCCH are identical to each other.

[0029] Beneficial effects

[0030] This specification is intended to improve the reliability of PDCCH reception by allowing terminals to receive the same DCI through multiple PDCCHs.

[0031] The beneficial effects that can be obtained from this specification are not limited to those mentioned above, and other beneficial effects not mentioned herein can be clearly understood by those skilled in the art from the following description. Attached Figure Description

[0032] Figure 1 This diagram illustrates an example of a wireless frame structure used in a wireless communication system.

[0033] Figure 2 This diagram illustrates an example of a downlink (DL) / uplink (UL) timeslot structure in a wireless communication system.

[0034] Figure 3 This is a diagram used to illustrate the physical channels used in 3GPP systems and typical signal transmission methods using these physical channels.

[0035] Figure 4a and Figure 4b The diagram illustrates the SS / PBCH block used for initial cell access in a 3GPP NR system.

[0036] Figure 5a and Figure 5b The diagram illustrates the process of transmitting control information and control channels in a 3GPP NR system.

[0037] Figure 6 The diagram shows a control resource set (CORESET) in a 3GPP NR system that can transmit the Physical Downlink Control Channel (PDCCH).

[0038] Figure 7 The diagram illustrates a method for configuring the PDCCH search space in a 3GPP NR system.

[0039] Figure 8 This is a conceptual diagram illustrating carrier aggregation.

[0040] Figure 9 This diagram is used to illustrate signal carrier communication and multi-carrier communication.

[0041] Figure 10 This is a diagram illustrating an example of the application of cross-carrier scheduling technology.

[0042] Figure 11 This is a block diagram illustrating the configuration of a UE and a base station according to an embodiment of the present disclosure.

[0043] Figure 12 The diagram illustrates the scheduling of a physical downlink shared channel according to an embodiment of the present disclosure.

[0044] Figure 13 The diagram illustrates the scheduling of the physical uplink control channel according to an embodiment of the present disclosure.

[0045] Figure 14 The diagram illustrates the scheduling of the physical uplink shared channel and the physical uplink control channel according to an embodiment of the present disclosure.

[0046] Figure 15 The illustration shows the repeated transmission of PDCCH in different control resource sets according to embodiments of the present disclosure.

[0047] Figure 16 The illustration shows repeated transmission of PDCCH in different search spaces according to embodiments of the present disclosure.

[0048] Figure 17 The illustration shows different repeating PDCCHs overlapping in the time-frequency domain according to an embodiment of the present disclosure.

[0049] Figure 18 The illustration depicts a problem that occurs when determining the time slots in which the physical downlink shared channel is scheduled, according to an embodiment of the present disclosure.

[0050] Figure 19 The illustration depicts a problem that occurs when determining the time slots for scheduling the physical uplink shared channel and the physical uplink control channel, according to an embodiment of the present disclosure.

[0051] Figure 20 The illustration shows the determination of a time slot based on a dynamic time slot format indicator according to an embodiment of the present disclosure.

[0052] Figure 21 The illustration depicts a problem that occurs when determining a timeslot based on a dynamic timeslot format indicator, according to an embodiment of the present disclosure.

[0053] Figure 22 The illustration shows the determination of time slots based on downlink preemption indication according to an embodiment of the present disclosure.

[0054] Figure 23 The illustration depicts a problem that occurs when a time slot is determined based on a downlink preemption indication, according to an embodiment of this disclosure.

[0055] Figure 24 The illustration shows a time slot determined according to an uplink cancellation instruction, based on an embodiment of the present disclosure.

[0056] Figure 25 The diagram illustrates the problem that occurs when a timeslot is determined based on an uplink cancellation instruction.

[0057] Figure 26 The illustration shows a method for determining a reference time slot according to an embodiment of the present disclosure.

[0058] Figure 27 The illustration shows a method for determining a reference time slot according to an embodiment of the present disclosure.

[0059] Figure 28 The illustration shows the activation of the PDCCH and the reception of the repeating PDCCH according to an embodiment of the present disclosure.

[0060] Figure 29 The diagram illustrates the configuration of a control resource set according to an embodiment of the present disclosure.

[0061] Figure 30 The diagram illustrates the configuration of a control resource set according to an embodiment of the present disclosure.

[0062] Figure 31The diagram illustrates a control resource set including a basic control resource set according to an embodiment of the present disclosure.

[0063] Figure 32 The diagram illustrates a control resource set including a basic control resource set according to an embodiment of the present disclosure.

[0064] Figure 33 The diagram illustrates a method for designing a control resource set using a basic control resource set according to an embodiment of the present disclosure.

[0065] Figure 34 The diagram illustrates a method for configuring a control resource set using a basic control resource set according to an embodiment of the present disclosure.

[0066] Figure 35 The illustration shows a method for indexing CCEs in a frequency-first manner according to an embodiment of the present disclosure.

[0067] Figure 36 The illustration shows a method for indexing CCEs in a time-first manner according to an embodiment of the present disclosure.

[0068] Figure 37 The illustration shows PDCCH candidates based on CCEs indexed in a frequency-first manner, according to an embodiment of the present disclosure.

[0069] Figure 38 The illustration shows PDCCH candidates based on time-priority indexed CCEs according to an embodiment of the present disclosure.

[0070] Figure 39 The illustration shows repeated reception of PDCCH on the basic control resource set according to an embodiment of the present disclosure.

[0071] Figure 40 The illustration shows repeated reception of PDCCH candidates by a terminal through interleaving of a basic control resource set according to an embodiment of the present disclosure.

[0072] Figure 41 The illustration shows repeated transmission of PDCCH across multiple search spaces according to an embodiment of the present disclosure.

[0073] Figure 42 The illustration shows the transmission of PDCCH based on search space and repeated configuration according to an embodiment of the present disclosure.

[0074] Figure 43 The illustration shows the transmission of PDCCH based on search space and repetitive configuration according to different start symbol positions, according to an embodiment of the present disclosure.

[0075] Figure 44 The illustration shows the transmission of PDCCH on multiple control resource sets according to embodiments of the present disclosure.

[0076] Figure 45 This is a flowchart illustrating the transmission of a repeated PDCCH according to an embodiment of the present disclosure. Detailed Implementation

[0077] The terminology used in this specification adopts, as far as possible, commonly used terms that are widely used in light of the functions of this invention; however, these terms may be modified according to the intent, practice, and emergence of new technologies of those skilled in the art. Furthermore, in certain cases, there are terms arbitrarily chosen by the applicant, and in such cases, their meaning will be described in the corresponding descriptive section of this invention. Therefore, it is intended to reveal that the terminology used in this specification should not be analyzed solely based on its name, but rather on its substantive meaning within the entire specification.

[0078] Throughout the specification and subsequent claims, when an element is described as being “connected” to another element, that element may be “directly connected” to the other element or “electrically connected” to the other element via a third element. Furthermore, unless explicitly stated otherwise, the word “comprising” will be understood to imply the inclusion of the stated element without implying the exclusion of any other elements. Additionally, in some exemplary embodiments, limitations such as “greater than or equal to” or “less than or equal to” based on a specific threshold may be appropriately replaced with “greater than” or “less than”, respectively.

[0079] The following technologies can be used in various wireless access systems: such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier-FDMA (SC-FDMA). CDMA can be implemented using wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using wireless technologies such as Global System for Mobile Communications (GSM), Universal Packet Radio Service (GPRS), and Enhanced Data Rate GSM Evolution (EDGE). OFDMA can be implemented using wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) using Evolved UMTS Terrestrial Radio Access (E-UTRA), and LTE Advanced (A) is an evolved version of 3GPP LTE. 3GPP New Radio (NR) is a system designed separately from LTE / LTE-A and is intended to support Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low Latency Communication (URLLC), and Massive Machine-Type Communication (mMTC) services as required by IMT-2020. For clarity, 3GPP NR is described primarily, but the technical concept of this invention is not limited thereto.

[0080] Unless otherwise specified in this specification, a base station may refer to a next-generation node B (gNB) as defined in 3GPP NR. Furthermore, unless otherwise stated, a terminal may refer to a user equipment (UE). In the following description, for the purpose of facilitating understanding, each element is separately divided into embodiments and described, but each embodiment may be used in conjunction with each other. In this disclosure, the configuration of the UE may be instructive of the configuration by the base station. Specifically, the base station may transmit channels or signals to the UE to configure parameter values ​​used in the UE's operation or wireless communication system.

[0081] Figure 1 This diagram illustrates an example of a wireless frame structure used in a wireless communication system.

[0082] refer to Figure 1 The radio frames (or radio frames) used in 3GPP NR systems can have a duration of 10 ms (Δf). max N f / 100) T c The length of the radio frame is Δf. Furthermore, a radio frame consists of 10 equal-sized subframes (SF). Here, Δf... max=480 10 3 Hz, N f =4096, T c =1 / (Δf ref N f,ref ), Δf ref =15 10 3 Hz, and N f,ref =2048. Numbers from 0 to 9 can be assigned to the 10 subframes within a single radio frame. Each subframe is 1 ms long and can include one or more time slots depending on the subcarrier spacing. More specifically, in 3GPP NR systems, a subcarrier spacing of 15 can be used. 2 μ The subcarrier spacing can be configured with μ values ​​of 0, 1, 2, 3, and 4. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz can be used for the subcarrier spacing. A subframe of 1 ms length can include 2... μ There are 2 time slots. In this case, the length of each time slot is 2. -μ ms. This can range from 0 to 2. μ The number -1 is assigned to 2 within a subframe. μ Each time slot. Furthermore, slots from 0 to 10 can be... 2 μ The number -1 is assigned to a time slot within a radio frame. Time resources can be distinguished by at least one of the radio frame number (also known as the radio frame index), subframe number (also known as the subframe index), and time slot number (or time slot index).

[0083] Figure 2 This diagram illustrates an example of a downlink (DL) / uplink (UL) timeslot structure in a wireless communication system. Specifically, Figure 2 The structure of the resource grid of the 3GPP NR system is shown.

[0084] Each online port has a resource grid. (See reference) Figure 2 A time slot comprises multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols in the time domain and multiple Resource Blocks (RBs) in the frequency domain. An OFDM symbol also refers to a symbol interval. Unless otherwise specified, an OFDM symbol may be simply referred to as a symbol. An RB comprises 12 consecutive subcarriers in the frequency domain. (See reference) Figure 2 The signal transmitted from each time slot can be composed of N size,μ grid,x N RBsc Subcarriers and N slot symb The resource grid of OFDM symbols is used for representation. Here, x = DL when the signal is a DL signal, and x = UL when the signal is a UL signal. N size,μ grid,x This represents the number of resource blocks (RBs) based on the subcarrier spacing component μ (x is DL or UL), and N slot symb Indicates the number of OFDM symbols in the time slot. N RB sc It is the number of subcarriers that make up an RB and N RB sc = 12. OFDM symbols can be referred to as cyclic shift OFDM (CP-OFDM) symbols or discrete Fourier transform extended OFDM (DFT-s-OFDM) symbols according to the multiple access scheme.

[0085] The number of OFDM symbols included in a time slot can vary depending on the length of the cyclic prefix (CP). For example, with normal CP, a time slot includes 14 OFDM symbols, but with extended CP, a time slot can include 12 OFDM symbols. In certain embodiments, extended CP can only be used with a 60 kHz subcarrier spacing. Figure 2 For ease of description, as an example, a time slot is configured with 14 OFDM symbols; however, embodiments of this disclosure can be applied in a similar manner to time slots with different numbers of OFDM symbols. References Figure 2 Each OFDM symbol includes N in the frequency domain. size,μ grid,x N RB sc Subcarriers can be categorized into data subcarriers for data transmission, reference signal subcarriers for reference signal transmission, and guard bands. The carrier frequency is also known as the center frequency (fc).

[0086] An RB can be composed of N in the frequency domain RB sc (For example, 12) consecutive subcarriers are defined. For reference, a resource configured with one OFDM symbol and one subcarrier can be called a resource element (RE) or tone. Therefore, an RB can be configured with N slot symb N RB sc Each resource element in the resource grid can be uniquely defined by a pair of indices (k, l) in a time slot. k can be from 0 to N in the frequency domain.size,μ grid, x N RB sc – 1 is the index assigned, and l can be from 0 to N in the time domain. slot symb – 1 The index assigned.

[0087] To enable the UE to receive or transmit signals from the base station, the UE's time / frequency can be synchronized with the base station's time / frequency. This is because when the base station and the UE are synchronized, the UE can determine the necessary time and frequency parameters to demodulate the DL signal and transmit the UL signal at the correct time.

[0088] Each symbol of a radio frame used in Time Division Duplex (TDD) or unpaired spectrum can be configured with at least one of DL symbol, UL symbol, and flexible symbol. Radio frames used as DL carriers in Frequency Division Duplex (FDD) or paired spectrum can be configured with either DL symbol or flexible symbol, while radio frames used as UL carriers can be configured with either UL symbol or flexible symbol. In a DL symbol, DL transmission is possible, but UL transmission is not. In a UL symbol, UL transmission is possible, but DL transmission is not. A flexible symbol can be determined as being used as either DL or UL based on the signal.

[0089] Information regarding the type of each symbol—that is, information indicating any of DL symbols, UL symbols, and flexible symbols—can be configured using cell-specific or public Radio Resource Control (RRC) signals. Furthermore, information regarding the type of each symbol can be additionally configured using UE-specific or dedicated RRC signals. The base station uses cell-specific RRC signals to inform i) the period of the cell-specific time slot configuration, ii) the number of time slots containing only DL symbols from the beginning of the cell-specific time slot configuration period, iii) the number of DL symbols starting from the first symbol of the time slot immediately following a time slot containing only DL symbols, iv) the number of time slots containing only UL symbols from the end of the cell-specific time slot configuration period, and v) the number of UL symbols starting from the last symbol of the time slot immediately preceding a time slot containing only UL symbols. Here, a symbol not configured with either UL or DL ​​symbols is a flexible symbol.

[0090] When information about symbol type is configured using UE-specific RRC signals, the base station can use cell-specific RRC signals to signal whether a flexible symbol is a DL symbol or a UL symbol. In this case, the UE-specific RRC signals cannot change a DL symbol or UL symbol configured using cell-specific RRC signals to another symbol type. The UE-specific RRC signals can signal the corresponding N of each time slot. slotsymb The number of DL symbols among the symbols and N of the corresponding time slot slot symb The number of UL symbols among the N symbols. In this case, the DL symbols of the time slot can be continuously configured from the first symbol to the i-th symbol of the time slot. In addition, the UL symbols of the time slot can be continuously configured from the j-th symbol to the last symbol of the time slot (where i < j). In the time slot, the symbol not configured with any of the UL symbols and DL symbols is a flexible symbol.

[0091] The type of symbol configured with the above RRC signal can be called semi-static DL / UL configuration. In the semi-static DL / UL configuration previously configured with the RRC signal, the flexible symbol can be indicated as a DL symbol, a UL symbol, or a flexible symbol by the dynamic time slot format information (SFI) sent on the physical downlink control channel (PDCCH). In this case, the DL symbol or UL symbol configured with the RRC signal does not change to another symbol type. Table 1 illustrates the dynamic SFI that the base station can indicate to the UE.

[0092] [Table 1]

[0093] In Table 1, D represents a DL symbol, U represents a UL symbol, and X represents a flexible symbol. As shown in Table 1, up to two DL / UL switches can be allowed in one time slot.

[0094] Figure 3 is a diagram for explaining the physical channels used in a 3GPP system (e.g., NR) and a typical signal transmission method using the physical channel.

[0095] If the power of the UE is turned on or the UE camps on a new cell, the UE performs initial cell search (S101). Specifically, the UE can synchronize with the BS in the initial cell search. To this end, the UE can receive the primary synchronization signal (PSS) and the secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as the cell ID. Thereafter, the UE can receive the physical broadcast channel from the base station and obtain the broadcast information in the cell.

[0096] After the initial cell search is completed, the UE receives the physical downlink shared channel (PDSCH) according to the physical downlink control channel (PDCCH) and the information in the PDCCH, so that the UE can obtain more specific system information than the system information obtained through the initial cell search (S102). Here, the system information received by the UE is the cell common system information in radio resource control (RRC) for the UE to operate properly at the physical layer and is called the remaining system information (RSMI) or system information block (SIB) 1.

[0097] When a UE initially accesses a base station or does not have radio resources for signal transmission (when the UE is in RRC_IDLE mode), the UE can perform a random access procedure to the base station (operations S103 to S106). First, the UE can send a preamble via the Physical Random Access Channel (PRACH) (S103) and receive a response message for the preamble from the base station via the PDCCH and the corresponding PDSCH (S104). When the UE receives a valid random access response message, the UE sends data including the UE's identifier to the base station via the Physical Uplink Shared Channel (PUSCH) indicated by the UL grant sent from the base station via the PDCCH (S105). Next, the UE waits for the reception of the PDCCH as an indication from the base station for conflict resolution. If the UE successfully receives the PDCCH via the UE's identifier (S106), the random access procedure is terminated. During the random access procedure, the UE can obtain UE-specific system information necessary for proper operation at the physical layer at the RRC layer. When the UE obtains the UE-specific system information from the RRC layer, the UE enters RRC_CONNECTED mode.

[0098] The RRC layer is used for message generation and management to control communication between the UE and the Radio Access Network (RAN). More specifically, in the RRC layer, the base station and UE can perform broadcasting of cell system information, management of paging message delivery, mobility management and handover, measurement reporting and its control, UE capability management, and storage management, including necessary management of existing data for all UEs in the cell. Typically, because the updates of signals transmitted from the RRC layer (hereinafter referred to as RRC signals) are longer than the transmission / reception period (i.e., transmission time interval, TTI) in the physical layer, RRC signals can remain unchanged for extended periods.

[0099] Following the above process, the UE receives the PDCCH / PDSCH (S107) and transmits the Physical Uplink Shared Channel (PUSCH) / Physical Uplink Control Channel (PUCCH) (S108) as a general UL / DL signal transmission process. Specifically, the UE can receive downlink control information (DCI) via the PDCCH. The DCI may include control information for the UE, such as resource allocation information. Furthermore, the format of the DCI can vary depending on the intended purpose. The uplink control information (UCI) transmitted by the UE to the base station via the UL includes DL / UL ACK / NACK signals, Channel Quality Indicator (CQI), Precoding Matrix Index (PMI), Rank Indicator (RI), etc. Here, CQI, PMI, and RI can be included in the Channel State Information (CSI). In a 3GPP NR system, the UE can transmit control information such as the aforementioned HARQ-ACK and CSI via the PUSCH and / or PUCCH.

[0100] Figure 4a and Figure 4b The diagram illustrates the SS / PBCH block used for initial cell access in a 3GPP NR system.

[0101] When power is on or when the UE wants to connect to a new cell, it can obtain time and frequency synchronization with that cell and perform an initial cell search procedure. The UE can detect the physical cell identifier N of the cell during the cell search procedure. cell ID Therefore, the UE can receive synchronization signals from the base station, such as the primary synchronization signal (PSS) and secondary synchronization signal (SSS), and synchronize with the base station. In this case, the UE can obtain information such as the cell identifier (ID).

[0102] refer to Figure 4a This section will describe synchronization signals (SS) in more detail. Synchronization signals can be classified into PSS and SSS. PSS can be used to obtain time-domain synchronization and / or frequency-domain synchronization, such as OFDM symbol synchronization and slot synchronization. SSS can be used to obtain frame synchronization and cell group ID. (Reference) Figure 4aAccording to Table 2, the SS / PBCH block can be configured with 20 consecutive RBs (=240 subcarriers) on the frequency axis and 4 consecutive OFDM symbols on the time axis. In this case, within the SS / PBCH block, the PSS is transmitted in the first OFDM symbol via subcarriers 56 to 182, and the SSS is transmitted in the third OFDM symbol. Here, the lowest subcarrier index of the SS / PBCH block is numbered starting from 0. In the first OFDM symbol for transmitting the PSS, the base station does not transmit signals via the remaining subcarriers, i.e., subcarriers 0 to 55 and subcarriers 183 to 239. Furthermore, in the third OFDM symbol for transmitting the SSS, the base station does not transmit signals via subcarriers 48 to 55 and subcarriers 183 to 191. The base station transmits the Physical Broadcast Channel (PBCH) via the remaining REs in the SS / PBCH block, excluding the signals mentioned above.

[0103] [Table 2]

[0104] The SS allows a total of 1008 unique physical layer cell IDs to be divided into 336 physical layer cell identifier groups through a combination of three PSSs and SSSs. Each group includes three unique identifiers, specifically ensuring that each physical layer cell ID is only a part of one physical layer cell identifier group. Therefore, the physical layer cell ID N cell ID = 3N (1) ID + N (2) ID An index N, ranging from 0 to 335, can be used to indicate the physical layer cell identifier group. (1) ID and an index N indicating the range of physical layer identifiers in the physical layer cell identifier group from 0 to 2. (2) ID Uniquely defined. The UE can detect the PSS and identify one of three unique physical layer identifiers. Furthermore, the UE can detect the SSS and identify one of 336 physical layer cell IDs associated with the physical layer identifier. In this case, the sequence d of the PSS... PSS (n) is as follows.

[0105]

[0106] here, And was given as .

[0107] In addition, the sequence d of SSS SSS (n) is as follows.

[0108]

[0109] here, And was given as .

[0110] A radio frame with a length of 10 ms can be divided into two half-frames with a length of 5 ms.

[0111] refer to Figure 4b This will describe the time slots for transmitting the SS / PBCH block in each half-frame. The time slots for transmitting the SS / PBCH block can be any of cases A, B, C, D, and E. In case A, the subcarrier spacing is 15 kHz and the start time of the SS / PBCH block is ({2, 8} + 14). (n) symbols. In this case, at carrier frequencies of 3 GHz or lower, n = 0 or 1. Furthermore, at carrier frequencies above 3 GHz but below 6 GHz, n can be 0, 1, 2, or 3. In case B, the subcarrier spacing is 30 kHz and the start time of the SS / PBCH block is {4, 8, 16, 20} + 28. n. In this case, at carrier frequencies of 3 GHz or lower, n = 0. Furthermore, at carrier frequencies above 3 GHz and below 6 GHz, n can be 0 or 1. In case C, the subcarrier spacing is 30 kHz and the start time of the SS / PBCH block is ({2, 8} + 14). (n) symbols. In this case, at carrier frequencies of 3 GHz or lower, n = 0 or 1. Furthermore, at carrier frequencies above 3 GHz but below 6 GHz, n can be 0, 1, 2, or 3. In case D, the subcarrier spacing is 120 kHz and the start time of the SS / PBCH block is the ({4, 8, 16, 20} + 28)th symbol. (n) symbols. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In case E, the subcarrier spacing is 240 kHz and the start time of the SS / PBCH block is the ({8, 12, 16, 20, 32, 36, 40, 44} + 56)th symbol. (n) symbols. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0112] Figure 5a and Figure 5bThe diagram illustrates the process of transmitting control information and using the control channel in a 3GPP NR system. (Reference) Figure 5a The base station can add a Cyclic Redundancy Check (CRC) masked with a Radio Network Temporary Identifier (RNTI) (e.g., XOR operation) to the control information (e.g., downlink control information (DCI)) (S202). The base station can scramble the CRC with an RNTI value determined according to the purpose / objective of each control information. The common RNTI used by one or more UEs can include at least one of System Information RNTI (SI-RNTI), Paging RNTI (P-RNTI), Random Access RNTI (RA-RNTI), and Transmit Power Control RNTI (TPC-RNTI). In addition, UE-specific RNTIs can include at least one of Cell Temporary RNTI (C-RNTI) and CS-RNTI. Thereafter, the base station can perform rate matching according to the amount of resources used for PDCCH transmission after performing channel coding (e.g., polarity compilation) (S204) (S206). Thereafter, the base station can multiplex the DCI based on the PDCCH structure based on Control Channel Elements (CCE) (S208). Furthermore, the base station can apply additional processes such as scrambling, modulation (e.g., QPSK), interleaving, etc., to the multiplexed DCI (S210), and then map the DCI to the resources to be transmitted. CCE is the basic resource unit used for PDCCH, and a CCE can include multiple (e.g., six) Resource Element Groups (REGs). A REG can be configured with multiple (e.g., 12) REs. The number of CCEs used for a PDCCH can be defined as the aggregation level. In 3GPPNR systems, aggregation levels of 1, 2, 4, 8, or 16 can be used. Figure 5b This is a diagram relating to CCE aggregation levels and PDCCH multiplexing, illustrating the type of CCE aggregation level used for a PDCCH and the CCEs sent in the control area accordingly.

[0113] Figure 6 The diagram shows a control resource set (CORESET) in a 3GPP NR system that can transmit the Physical Downlink Control Channel (PDCCH).

[0114] A CORESET is a time-frequency resource in which PDCCH (i.e., control signals for the UE) is transmitted. Furthermore, a search space, described later, can be mapped to a CORESET. Therefore, the UE can monitor the time-frequency domain designated as a CORESET instead of all frequency bands used for PDCCH reception and decode the PDCCH mapped to the CORESET. The base station can configure one or more CORESETs for each cell for the UE. A CORESET can be configured with up to three consecutive symbols on the time axis. Additionally, a CORESET can be configured in units of six consecutive PRBs on the frequency axis. In the embodiment of Figure 5, CORESET #1 is configured with consecutive PRBs, while CORESET #2 and CORESET #3 are configured with discontinuous PRBs. A CORESET can reside in any symbol of a time slot. For example, in the embodiment of Figure 5, CORESET #1 begins at the first symbol of the time slot, CORESET #2 begins at the fifth symbol of the time slot, and CORESET #9 begins at the ninth symbol of the time slot.

[0115] Figure 7 The diagram illustrates a method for setting up the PDCCH search space in a 3GPP NR system.

[0116] To transmit PDCCH to a UE, each CORESET may have at least one search space. In embodiments of this disclosure, the search space is the set of all time-frequency resources (hereinafter referred to as PDCCH candidates) capable of being used to transmit a UE's PDCCH. The search space may include a common search space that requires UEs of 3GPP NR to search together and a terminal-specific search space or UE-specific search space that requires a specific UE to search. In the common search space, a UE may monitor a PDCCH that is configured to be searched together by all UEs belonging to the same base station cell. Furthermore, a UE-specific search space may be set for each UE, such that the UE monitors the PDCCH allocated to each UE at search space locations that differ depending on the UE. In the case of a UE-specific search space, the search spaces between UEs may partially overlap and be allocated due to the limited control area that can be allocated PDCCH. Monitoring the PDCCH includes blind decoding of PDCCH candidates in the search space. When blind decoding is successful, it can be expressed as (successfully) detecting / receiving the PDCCH, and when blind decoding fails, it can be expressed as not detecting / receiving or not successfully detecting / receiving the PDCCH.

[0117] For ease of explanation, a PDCCH scrambled with a Group Common (GC) RNTI previously known to one or more UEs to transmit DL control information to one or more UEs is called a Group Common (GC) PDCCH or a common PDCCH. Furthermore, a PDCCH scrambled with a RNTI of a specific terminal already known to a specific UE to transmit UL scheduling information or DL ​​scheduling information to that specific UE is called a UE-specific PDCCH. Common PDCCHs can be included in the common search space, and UE-specific PDCCHs can be included in either the common search space or the UE-specific PDCCH.

[0118] The base station can signal to each UE or group of UEs via the PDSCH information regarding resource allocation for the Paging Channel (PCH) and Downlink Shared Channel (DL-SCH) as transport channels (i.e., DL clearance) or resource allocation for the Uplink Shared Channel (UL-SCH) and Hybrid Automatic Repeat Request (HARQ) (i.e., UL clearance). The base station can transmit PCH transport blocks and DL-SCH transport blocks via the PDSCH. The base station can also transmit data excluding specific control information or specific service data via the PDSCH. Furthermore, the UE can receive data excluding specific control information or specific service data via the PDSCH.

[0119] The base station can include information in the PDCCH about which UE (one or more UEs) the PDSCH data is sent to and how the PDSCH data will be received and decoded by the corresponding UE, and then send the PDCCH. For example, suppose the DCI sent on a particular PDCCH is CRC masked with RNTI "A", and the DCI indicates that the PDSCH is allocated to radio resource "B" (e.g., frequency location) and indicates transmission format information "C" (e.g., transport block size, modulation scheme, coding information, etc.). The UE uses the RNTI information it possesses to monitor the PDCCH. In this case, if there is a UE performing blind decoding of the PDCCH using RNTI "A", then that UE receives the PDCCH and, based on the information in the received PDCCH, receives the PDSCH indicated by "B" and "C".

[0120] Table 3 shows an example of the Physical Uplink Control Channel (PUCCH) used in a wireless communication system.

[0121] [Table 3]

[0122] PUCCH can be used to send the following UL control information (UCI).

[0123] - Scheduling Request (SR): Information used to request UL UL-SCH resources.

[0124] - HARQ-ACK: A response to the PDCCH (indicating DL SPS release) and / or to a DL transport block (TB) on the PDSCH. HARQ-ACK indicates whether information transmitted on the PDCCH or PDSCH has been received. HARQ-ACK responses include positive ACK (simply ACK), negative ACK (NACK hereinafter), discontinuous transmission (DTX), or NACK / DTX. Here, the terms HARQ-ACK are used interchangeably with HARQ-ACK / NACK and ACK / NACK. Typically, ACK can be represented by a bit value of 1, while NACK can be represented by a bit value of 0.

[0125] - Channel State Information (CSI): Feedback information about the DL channel. The UE generates it based on the CSI-reference signal (RS) transmitted by the base station. MIMO-related feedback information includes the Rank Indicator (RI) and the Precoding Matrix Indicator (PMI). The CSI can be divided into CSI Part 1 and CSI Part 2 based on the information indicated by the CSI.

[0126] In the 3GPP NR system, five PUCCH formats can be used to support various service scenarios, channel environments, and frame structures.

[0127] PUCCH format 0 is a format capable of transmitting 1 or 2 bits of HARQ-ACK information or SR. PUCCH format 0 can be transmitted using one or two OFDM symbols on the time axis and one PRB on the frequency axis. When transmitting PUCCH format 0 in two OFDM symbols, the same sequence on both symbols can be transmitted using different RBs. In this case, the sequence can be a cyclically shifted (CS) sequence from the base sequence used for PUCCH format 0. This allows the UE to obtain frequency diversity gain. Specifically, the UE can, according to M... bit Bit UCI (M) bit = 1 or 2) to determine the cyclic shift (CS) value m cs Furthermore, the 12-length base sequence is based on a predetermined CS value m. cs The cyclically shifted sequence can be mapped to one OFDM symbol of one RB and 12 REs and transmitted. When the number of cyclic shifts available to the UE is 12 and M... bit When M = 1, 1 bit UCI0 and 1 can be mapped to two cyclic shift sequences with a difference of 6, respectively. Furthermore, when M... bitWhen = 2, the 2-bit UCI 00, 01, 11 and 10 can be mapped to four cyclic shift sequences with a difference of 3 in their cyclic shift values.

[0128] PUCCH format 1 can deliver 1 or 2 bits of HARQ-ACK information or SR. PUCCH format 1 can be transmitted using consecutive OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 can be one of 4 to 14. More specifically, it can be used for M... bit BPSK modulation is performed using a UCI of 1. The UE can then utilize Quadrature Phase Shift Keying (QPSK) to modulate the M... bit Modulation is performed using a UCI of 2. The signal is obtained by multiplying the modulated complex-valued symbol d(0) by a sequence of length 12. In this case, the sequence can be the base sequence used for PUCCH format 0. The UE transmits the obtained signal by extending the even-numbered OFDM symbols assigned to PUCCH format 1 with a time-axis orthogonal cover code (OCC). PUCCH format 1 determines the maximum number of different UEs multiplexed in an RB based on the length of the OCC to be used. The demodulation reference signal (DMRS) can be extended with the OCC and mapped to the odd-numbered OFDM symbols of PUCCH format 1.

[0129] PUCCH format 2 can deliver more than 2 bits of UCI. PUCCH format 2 can be transmitted via one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. When transmitting PUCCH format 2 in two OFDM symbols, the sequences transmitted in different RBs through the two OFDM symbols can be identical. Here, the sequence can be multiple modulated complex-valued symbols d(0), ..., d(M). symbol -1). Here, M symbol It can be M bit / 2. Through this, the UE can obtain frequency diversity gain. More specifically, for M... bit One bit of UCI (M bit >2) Perform bit-level scrambling, QPSK modulation, and map it to one or two OFDM symbols' RBs. Here, the number of RBs can be one from 1 to 16.

[0130] PUCCH format 3 or PUCCH format 4 can deliver more than 2 bits of UCI. PUCCH format 3 or PUCCH format 4 can be transmitted via consecutive OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 can be one of 4 to 14. Specifically, the UE utilizes 2 / 3 binary phase shift keying (BPSK) or QPSK to transmit M... bit One bit of UCI (M bit >2) Modulate to generate complex numerical symbols d(0) to d(M) symb -1). Here, when using π / 2-BPSK, M symb = M bit However, when using QPSK, M symb = M bit / 2. The UE may not apply block unit extension to PUCCH format 3. However, the UE may use a 12-length PreDFT-OCC to apply block unit extension to one RB (i.e., 12 subcarriers), allowing PUCCH format 4 to have two or four multiplexing capabilities. The UE performs transmit precoding (or DFT precoding) on ​​the extended signal and maps it to each RE to transmit the extended signal.

[0131] In this scenario, the number of Restricted Blocks (RBs) occupied by PUCCH Format 2, PUCCH Format 3, or PUCCH Format 4 can be determined based on the length of the UCI sent by the UE and the maximum coding rate. When the UE uses PUCCH Format 2, it can send HARQ-ACK and CSI information together via PUCCH. When the number of RBs that the UE can send exceeds the maximum number of RBs that can be used with PUCCH Format 2, PUCCH Format 3, or PUCCH Format 4, the UE can send only the remaining UCI information without sending some, based on the priority of the UCI information.

[0132] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured using the RRC signal to indicate frequency hopping in the time slot. When frequency hopping is configured, the index of the RB to be hopped can be configured using the RRC signal. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted over N OFDM symbols on the time axis, the first hop can have floor (N / 2) OFDM symbols and the second hop can have ceiling (N / 2) OFDM symbols.

[0133] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured to be repeatedly transmitted in multiple time slots. In this case, the number K of time slots in which the PUCCH is repeatedly transmitted can be configured via an RRC signal. The repeatedly transmitted PUCCH must begin at a constant position in the OFDM symbol within each time slot and have a constant length. When one of the OFDM symbols in the time slot where the UE should transmit the PUCCH is indicated as a DL symbol via an RRC signal, the UE can choose not to transmit the PUCCH in the corresponding time slot and delay the transmission of the PUCCH to the next time slot.

[0134] In 3GPP NR systems, a UE can perform transmission / reception using a bandwidth less than or equal to the carrier (or cell) bandwidth. For this purpose, the UE can be configured with a bandwidth portion (BWP) consisting of a continuous bandwidth comprising a portion of the carrier's bandwidth. A UE operating under TDD or in unpaired spectrum can receive up to four DL / UL BWP pairs for one carrier (or cell). Furthermore, a UE can activate one DL / UL BWP pair. A UE operating under FDD or in paired spectrum can receive up to four DL BWPs on a downlink carrier (or cell) and up to four UL BWPs on an uplink carrier (or cell). For each carrier (or cell), the UE can activate one DL BWP and one UL BWP. The UE may not receive or transmit in time-frequency resources other than the activated BWP. The activated BWP can be referred to as the active BWP.

[0135] The base station can indicate the active BWP among the BWPs configured by the UE via downlink control information (DCI). The BWP indicated by the DCI is activated, while other configured BWPs are deactivated. In a TDD-operated carrier (or cell), the base station can include a Bandwidth Part Indicator (BPI) indicating the active BWP in the DCI of the scheduling PDSCH or PUSCH to change the UE's DL / UL BWP pair. The UE can receive the DCI of the scheduling PDSCH or PUSCH and can identify the active DL / UL BWP pair based on the BPI. In the case of a downlink carrier (or cell) operating in FDD, the base station can include a BPI indicating the active BWP in the DCI of the scheduling PDSCH to change the UE's DL BWP. In the case of an uplink carrier (or cell) operating in FDD, the base station can include a BPI indicating the active BWP in the DCI of the scheduling PUSCH to change the UE's UL BWP.

[0136] Figure 8 This is a conceptual diagram illustrating carrier aggregation.

[0137] Carrier aggregation is a method in which a UE uses multiple frequency blocks or (in a logical sense) cells configured with UL resources (or component carriers) and / or DL ​​resources (or component carriers) as a large logical band so that the wireless communication system can use a wider bandwidth. A component carrier can also be referred to by the terms primary cell (PCell), secondary cell (SCell), or primary SCell (PScell). However, for convenience of description, the term "component carrier" will be used below.

[0138] refer to Figure 8 As an example of a 3GPP NR system, the entire system bandwidth can include up to 16 component carriers, and each component carrier can have a bandwidth of up to 400 MHz. Component carriers can include one or more physically contiguous subcarriers. Although in Figure 8 The diagram shows each component carrier with the same bandwidth, but this is merely an example, and each component carrier can have a different bandwidth. Furthermore, although each component carrier is shown as adjacent to each other on the frequency axis, the diagram is shown conceptually, and each component carrier can be physically adjacent to each other or spaced apart.

[0139] Different center frequencies can be used for each component carrier. Alternatively, a common center frequency can be used for physically adjacent component carriers. Assuming in Figure 8 In one embodiment, all component carriers are physically adjacent, so center frequency A can be used in all component carriers. Alternatively, assuming that the component carriers are not physically adjacent to each other, then center frequency A and center frequency B can be used in each component carrier.

[0140] When extending the total system bandwidth through carrier aggregation, the bandwidth used for communication with each UE can be defined on a component carrier basis. UE A can use 100 MHz as the total system bandwidth and perform communication using all five component carriers. UEs B1-B5 can perform communication using only 20 MHz bandwidth and one component carrier. UEs C1 and C2 can each use 40 MHz bandwidth and two component carriers for communication. These two component carriers can be logically / physically adjacent or non-adjacent. UE C1 represents the case of using two non-adjacent component carriers, while UE C2 represents the case of using two adjacent component carriers.

[0141] Figure 9 This is a diagram used to illustrate signal carrier communication and multi-carrier communication. Specifically, Figure 9 (a) shows the single-carrier subframe structure and Figure 9 (b) shows the multi-carrier subframe structure.

[0142] refer to Figure 9 (a) In FDD mode, a typical wireless communication system can perform data transmission or reception using a DL band and a corresponding UL band. In another specific embodiment, in TDD mode, the wireless communication system can divide radio frames into UL time units and DL time units in the time domain, and perform data transmission or reception using the UL / DL time units. (See reference...) Figure 9 (b) It is possible to aggregate three 20 MHz component carriers (CCs) into each of the UL and DL, enabling a bandwidth of 60 MHz. Each CC can be adjacent to or not adjacent to each other in the frequency domain. Figure 9 (b) illustrates a case where the bandwidth of the UL CC and the DL CC are the same and symmetrical, but the bandwidth of each CC can be determined independently. Furthermore, asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is possible. The DL / UL CCs allocated / configured to a specific UE via RRC can be referred to as the serving DL / UL CCs for that specific UE.

[0143] A base station can communicate with a UE by activating some or all of the UE's serving CCs or by deactivating some CCs. The base station can change the CCs to be activated / deactivated, and can change the number of CCs to be activated / deactivated. If the base station allocates CCs available to the UE as cell-specific or UE-specific, at least one of the allocated CCs will not be deactivated unless the CC allocation for the UE is completely reconfigured or the UE is handed over. A CC that is not deactivated by the UE is called the primary CC (PCC) or primary cell (PCell), while CCs that the base station can freely activate / deactivate are called secondary CCs (SCCs) or secondary cells (SCells).

[0144] Meanwhile, 3GPP NR uses the concept of cells to manage radio resources. A cell is defined as a combination of DL resources and UL resources, i.e., a combination of DL CC and UL CC. A cell can be configured with DL resources alone, or it can be configured with a combination of DL resources and UL resources. When carrier aggregation is supported, the link between the carrier frequencies of DL resources (or DL ​​CC) and UL resources (or UL CC) can be indicated by system information. The carrier frequency refers to the center frequency of each cell or CC. The cell corresponding to a PCC is called a PCell, and the cell corresponding to an SCC is called an SCell. The carrier corresponding to a PCell in DL is the DL PCC, and the carrier corresponding to a PCell in UL is the UL PCC. Similarly, the carrier corresponding to an SCell in DL is the DL SCC, and the carrier corresponding to an SCell in UL is the UL SCC. Depending on the UE's capabilities, a serving cell can be configured with one PCell and zero or more SCells. In the case of a UE in the RRC_CONNECTED state but not configured for carrier aggregation or not supporting carrier aggregation, only one serving cell is configured with only a PCell.

[0145] As mentioned above, the term "cell" used in carrier aggregation is distinguished from the term "cell" referring to a geographical area that provides communication services through a base station or an antenna array. That is, a component carrier can also be referred to as a scheduled cell, a scheduled cell, a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, to distinguish between cells representing a geographical area and cells in carrier aggregation, in this disclosure, cells in carrier aggregation are referred to as CCs, and cells representing a geographical area are referred to as cells.

[0146] Figure 10 This diagram illustrates an example of cross-carrier scheduling technology. When cross-carrier scheduling is set up, the control channel transmitted via the first CC can use the Carrier Indicator Field (CIF) to schedule the data channel transmitted via either the first CC or the second CC. The CIF is included in the DCI. In other words, a scheduling cell is set up, and the DL license / UL license transmitted in the PDCCH area of ​​that scheduling cell schedules the PDSCH / PUSCH of the scheduled cell. That is, there is a search area for multiple component carriers in the PDCCH area of ​​the scheduling cell. A PCell can essentially be a scheduling cell, and a specific SCell can be designated as a scheduling cell by a higher layer.

[0147] exist Figure 10In the embodiments described, it is assumed that three DL CCs are combined. Here, it is assumed that DL component carrier #0 is a DLPCC (or PCell), and DL component carriers #1 and #2 are DL SCCs (or SCells). Furthermore, it is assumed that the DLPCC is configured as a PDCCH monitoring CC. When cross-carrier scheduling is not configured via UE-specific (or UE group-specific or cell-specific) higher-layer signaling, CIF is disabled, and each DL CC can transmit only the PDCCH for scheduling its PDSCH according to the NR PDCCH rules without CIF (non-cross-carrier scheduling, self-carrier scheduling). Meanwhile, if cross-carrier scheduling is configured via UE-specific (or UE group-specific or cell-specific) higher-layer signaling, CIF is enabled, and a specific CC (e.g., DL PCC) can use CIF to transmit not only the PDCCH for scheduling DL CC A but also the PDCCH for scheduling another CC (cross-carrier scheduling). On the other hand, no PDCCH is transmitted in another DL CC. Therefore, the UE monitors the PDCCH excluding CIF to receive the PDSCH of self-carrier scheduling depending on whether cross-carrier scheduling is configured for the UE, or monitors the PDCCH including CIF to receive the PDSCH of cross-carrier scheduling.

[0148] on the other hand, Figure 9 and Figure 10 The diagram illustrates the subframe structure of a 3GPP LTE-A system, and the same or similar configuration can be applied to a 3GPP NR system. However, in a 3GPP NR system, Figure 9 and Figure 10 Subframes can be replaced with time slots.

[0149] Figure 11 This is a block diagram illustrating the configuration of a UE and a base station according to an embodiment of the present disclosure.

[0150] In embodiments of this disclosure, the UE can be implemented using various types of wireless communication devices or computing devices that are guaranteed to be portable and mobile. The UE can be referred to as User Equipment (UE), Station (STA), Mobile Subscriber (MS), etc. Furthermore, in embodiments of this disclosure, the base station controls and manages cells (e.g., macro cells, femtocells, picocells, etc.) corresponding to the service area, and performs functions such as signal transmission, channel designation, channel monitoring, self-diagnosis, and relaying. The base station can be referred to as Next Generation Node B (gNB) or Access Point (AP).

[0151] As shown in the accompanying drawings, the UE 100 according to an embodiment of the present disclosure may include a processor 110, a communication module 120, a memory 130, a user interface 140, and a display unit 150.

[0152] First, the processor 110 can execute various instructions or procedures and process data within the UE 100. Furthermore, the processor 110 can control the overall operation of each unit including the UE 100 and can control the transmission / reception of data between the units. Here, the processor 110 can be configured to perform operations according to the embodiments described in this disclosure. For example, the processor 110 can receive time slot configuration information, determine a time slot configuration based on the time slot configuration information, and perform communication according to the determined time slot configuration.

[0153] Next, the communication module 120 can be an integrated module that uses a wireless communication network to perform wireless communication and uses a wireless LAN to perform wireless LAN access. For this purpose, the communication module 120 can include multiple network interface cards (NICs), such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123, either internally or externally. In the accompanying drawings, the communication module 120 is shown as a monolithic integrated module; however, unlike the drawings, each network interface card can be arranged independently depending on the circuit configuration or usage.

[0154] Cellular communication interface card 121 can transmit or receive radio signals with at least one of base station 200, external device, and server using a mobile communication network and provide cellular communication services in a first frequency band based on instructions from processor 110. According to an embodiment, cellular communication interface card 121 may include at least one NIC module using a frequency band less than 6 GHz. At least one NIC module of cellular communication interface card 121 can independently perform cellular communication with at least one of base station 200, external device, and server in accordance with cellular communication standards or protocols in the sub-6 GHz frequency band supported by the corresponding NIC module.

[0155] Cellular communication interface card 122 can transmit or receive radio signals with at least one of base station 200, external device, and server using a mobile communication network and provide cellular communication services in a second frequency band based on instructions from processor 110. According to an embodiment, cellular communication interface card 122 may include at least one NIC module using a frequency band greater than 6 GHz. At least one NIC module of cellular communication interface card 122 can independently perform cellular communication with at least one of base station 200, external device, and server in accordance with cellular communication standards or protocols in a frequency band above 6 GHz supported by the corresponding NIC module.

[0156] The unlicensed frequency band communication interface card 123 transmits or receives radio signals with at least one of the base station 200, external devices, and servers by using a third frequency band that is an unlicensed frequency band, and provides unlicensed frequency band communication services based on instructions from the processor 110. The unlicensed frequency band communication interface card 123 may include at least one NIC module using an unlicensed frequency band. For example, the unlicensed frequency band may be a band of 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or a band higher than 52.6 GHz. At least one NIC module of the unlicensed frequency band communication interface card 123 may independently or dependently perform wireless communication with at least one of the base station 200, external devices, and servers according to the unlicensed frequency band communication standard or protocol supported by the corresponding NIC module.

[0157] The memory 130 stores the control program used in the UE 100 and various data used therein. Such a control program may include a prescribed program required to perform wireless communication with at least one of the base station 200, external devices, and servers.

[0158] Next, the user interface 140 includes various input / output means provided in the UE 100. In other words, the user interface 140 can use various input means to receive user input, and the processor 110 can control the UE 100 based on the received user input. Furthermore, the user interface 140 can use various output means to execute output based on instructions from the processor 110.

[0159] Next, the display unit 150 outputs various images on the display screen. The display unit 150 can output various display objects, such as content executed by the processor 110 or a user interface, based on control instructions from the processor 110.

[0160] Furthermore, the base station 200 according to embodiments of the present disclosure may include a processor 210, a communication module 220, and a memory 230.

[0161] First, the processor 210 can execute various instructions or programs and process the internal data of the base station 200. Furthermore, the processor 210 can control the overall operation of each unit in the base station 200 and control the transmission and reception of data between the units. Here, the processor 210 can be configured to perform operations according to the embodiments described in this disclosure. For example, the processor 210 can notify time slot configurations with signals and perform communication based on the time slot configurations notified by the used signals.

[0162] Next, the communication module 220 can be an integrated module that uses a wireless communication network to perform wireless communication and uses a wireless LAN to perform wireless LAN access. For this purpose, the communication module 220 can include multiple network interface cards, such as cellular communication interface cards 221 and 222 and an unlicensed frequency band communication interface card 223, either internally or externally. In the accompanying drawings, the communication module 220 is shown as a monolithic integrated module; however, unlike the drawings, each network interface card can be arranged independently depending on the circuit configuration or usage.

[0163] Cellular communication interface card 221 can transmit or receive radio signals with at least one of base station 100, external device, and server using a mobile communication network and provide cellular communication services in a first frequency band based on instructions from processor 210. According to an embodiment, cellular communication interface card 221 may include at least one NIC module using a frequency band less than 6 GHz. At least one NIC module of cellular communication interface card 221 can independently perform cellular communication with at least one of base station 100, external device, and server in accordance with cellular communication standards or protocols in a frequency band less than 6 GHz supported by the corresponding NIC module.

[0164] Cellular communication interface card 222 can transmit or receive radio signals with at least one of base station 100, external device, and server using a mobile communication network and provide cellular communication services in a second frequency band based on instructions from processor 210. According to an embodiment, cellular communication interface card 222 may include at least one NIC module using a frequency band of 6 GHz or higher. At least one NIC module of cellular communication interface card 222 can independently perform cellular communication with at least one of base station 100, external device, and server in accordance with cellular communication standards or protocols in a frequency band of 6 GHz or higher supported by the corresponding NIC module.

[0165] The unlicensed frequency band communication interface card 223 transmits or receives radio signals with at least one of the base station 100, external devices, and servers by using a third frequency band that is an unlicensed frequency band, and provides unlicensed frequency band communication services based on instructions from the processor 210. The unlicensed frequency band communication interface card 223 may include at least one NIC module using an unlicensed frequency band. For example, the unlicensed frequency band may be a band of 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or a band higher than 52.6 GHz. At least one NIC module of the unlicensed frequency band communication interface card 223 can independently or dependently perform wireless communication with at least one of the base station 100, external devices, and servers in accordance with the unlicensed frequency band communication standards or protocols of the frequency band supported by the corresponding NIC module.

[0166] Figure 11This is a block diagram illustrating a UE 100 and a base station 200 according to an embodiment of the present disclosure, and the blocks shown individually are logically divided elements of the device. Therefore, the aforementioned elements of the device can be installed in a single chip or multiple chips depending on the device design. Furthermore, a portion of the configuration of the UE 100, such as a user interface 140, a display unit 150, etc., may be selectively provided in the UE 100. Additionally, the user interface 140, display unit 150, etc., may be additionally provided in the base station 200 if necessary.

[0167] The UE can receive the Physical Downlink Control Channel (PDCCH) transmitted from the base station. The UE can receive information such as the Control Resource Set (CORESET) or search space from the base station to receive the downlink control channel.

[0168] The control resource set may include frequency domain information about where the physical downlink control channel should be received. Specifically, the base station may provide the UE with information about the control resource set. Here, the information about the control resource set may include the index and number of consecutive symbols of the physical resource block (PRB) or set of PRBs from which the UE should receive the physical downlink control channel. Here, the number of consecutive symbols may be one of 1, 2, and 3.

[0169] The search space may include timing information for receiving a set of PRBs indicated by the control resource set. Specifically, the base station may provide the UE with information about the search space. Here, the information about the search space may include at least one of period and offset. Here, the period and offset may be configured in units of time slots, sub-time slots, symbols, or symbol sets, or time slot sets. The information about the search space may include the CCE aggregation level (AL) received by the UE, the number of PDCCHs monitored by the UE for each CCE aggregation level, the search space type, the DCI format monitored by the UE, and RNTI information.

[0170] The CCE aggregation level can have at least one of 1, 2, 4, 8, and 16. The UE can monitor the PDCCH in the same number of CCEs as the CCE aggregation level value.

[0171] The search space can be divided into two types. Specifically, the search space can be divided into a common search space (CSS) and a UE-specific search space. The common search space can be a search space where all UEs in the cell or some UEs in the cell jointly monitor the PDCCH. A UE can be configured to monitor PDCCH candidates broadcast to all UEs in the cell or some UEs in the cell (e.g., PDCCHs for transmitting DCIs with a CRC scrambled by at least one of the following RNTIs: SI-RNTI, RA-RNTI, MsgB-RNTI, P-RNTI, TC-RNTI, INT-RNTI, SFI-RNTI, TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, TPC-SRS-RNTI, CI-RNTI, C-RNTI, MCS-C-RNTI, CS-RNTI, or PS-RNTI) in the common search space and be configured to receive PDCCHs. The UE-specific search space can be a search space where a specific UE monitors the PDCCH. A specific UE can be configured to monitor PDCCH candidates sent to that specific UE in its UE-specific search space (e.g., PDCCH for transmitting a DCI with a CRC scrambled by at least one of the following RNTIs: C-RNTI, MCS-C-RNTI, SP-CSI-RNTI, CS-RNTI, SL-RNTI, SL-CS-RNTI, or SL-L-CS-RNTI), and is configured to receive PDCCHs. Additionally, the UE can receive PDCCHs in both the common search space and the UE-specific search space that include DCIs indicating reception of the Physical Downlink Shared Channel, transmission of the Physical Uplink Control Channel, or transmission of the Physical Uplink Shared Channel.

[0172] The DCI format monitored by the UE for scheduling PUSCH transmission and PDSCH reception received from the base station can be DCI formats 0_0, 0_1, 0_2, 1_0, 1_1, and 1_2. In the cases of DCI formats 0_0, 0_1, 0_2, 1_0, 1_1, and 1_2, the RNTI information can include at least one of CS-RNTI, MCS-C-RNTI, and C-RNTI. Here, CS-RNTI can be used to activate / release semi-persistent scheduling (SPS) PDSCH or configuration-granted (CG) PUSCH. Additionally, CS-RNTI can be used to schedule retransmissions of SPSPDSCH or CG PUSCH. Here, MCS-C-RNTI can be used to schedule PDSCH or PUSCH using a modulation and coding scheme (MCS) with high reliability. C-RNTI can be used to schedule PDSCH or PUSCH.

[0173] The DCI format that can be included in the PDCCH monitored by the UE can further include the following information.

[0174] DCI format 2_0 may include information about the dynamic slot format indicator (SFI) indicating the direction of the symbols constituting the slot. Here, the direction of the symbol can be uplink, downlink, or flexible. In this case, symbols with an uplink direction can be used for uplink transmission, symbols with a downlink direction can be used for downlink reception, and symbols with a flexible direction can be used for both uplink transmission and downlink reception. The RNTI used for DCI format 2_0 can be an SFI-RNTI.

[0175] DCI format 2_1 may include an indication that a downlink (DL) preemption indication or interruption indication is not present in the PRB and symbols transmitted by the base station to the UE. The RNTI used for DCI format 2_1 may be an INT-RNTI.

[0176] DCI format 2_4 may include an uplink (UL) cancellation indication that indicates the cancellation of an uplink transmission performed by the UE to the base station on the PRB. The RNTI used for DCI format 2_4 may be a CI-RNTI.

[0177] The UE can determine PDCCH candidates for receiving PDCCH based on the configured control resource set and information about the search space. After detecting a PDCCH candidate and checking the CRC based on the RNTI value, the UE can determine whether the correct PDCCH has been received. The RNTI value can include SFI-RNTI, INT-RNTI, and CI-RNTI values, as well as at least C-RNTI, MCS-C-RNTI, and CS-RNTI.

[0178] When the UE receives the PDCCH, it can perform the operation indicated by the DCI by decoding the information about the control resource set and search space based on the DCI included in the PDCCH. Here, the format of the DCI included in the PDCCH received by the UE can be one of DCI formats 0_0, 0_1, and 0_2 used for scheduling PUSCH. Additionally, the format of the DCI included in the PDCCH received by the UE can be one of DCI formats 1_0, 1_1, and 1_2 used for scheduling PDSCH. Furthermore, the format of the DCI included in the PDCCH received by the UE can be one of DCI formats 1_0, 1_1, and 1_2 used for scheduling PUCCH. Here, the PUCCH may include HARQ-ACK information. Additionally, the format of the DCI included in the PDCCH received by the UE can be one of DCI formats 2_0, 2_1, and 2_4.

[0179] When the UE receives DCI formats 1_0, 1_1, and 1_2 for scheduling PDSCH, the UE can receive the PDSCH scheduled by the DCI. For this purpose, the UE should determine the time slot in which the PDSCH is scheduled, as well as the start index and length (number of symbols) of the symbols in that time slot, based on the received DCI. The Time Domain Resource Assignment (TDRA) field of the DCI formats 1_0, 1_1, and 1_2 received by the UE can indicate the value of K0 corresponding to the timing information of the scheduling time slot, the index of the start symbol in the time slot, and the start length indicator value (SLIV value) corresponding to its length. Here, the value of K0 can be a non-negative integer value. Here, SLIV can be a value obtained by jointly encoding the index (S) and length (L) values ​​of the start symbol in the time slot. The index (S) and length (L) values ​​of the start symbol in the time slot can be values ​​transmitted separately. Here, in the case of normal CP, S can have one of 0, 1, ..., 13. In this case, L can be one of the natural numbers that satisfy the condition, and here, the value of (S+L) is equal to or less than 14. In the case of extended CP, S can be one of 0, 1, ..., and 11. In this case, L can be one of the natural numbers that satisfy the condition, and here, the value of (S+L) is equal to or less than 12.

[0180] The UE can determine the time slot in which it should receive PDSCH based on the K0 value. Specifically, the UE can determine the time slot in which it should receive PDSCH based on the K0 value and the index of the time slot in which DCI is received, the subcarrier spacing (SCS) of the DL BWP receiving DCI, and the subcarrier spacing of the DL BWP receiving the scheduled PDSCH.

[0181] For example, there might be a situation where the subcarrier spacing of the DL BWP receiving DCI is the same as the subcarrier spacing of the DL BWP receiving the scheduled PDSCH, and the DCI is received in downlink time slot n. Here, the UE can receive the PDSCH in downlink time slot (n+K0). In this specification, time slot x can represent the time slot with index x or the x-th time slot.

[0182] For example, the subcarrier spacing of the DL BWP receiving DCI is 15 kHz. 2^mu_PDCCH, the subcarrier spacing of the DL BWP receiving the scheduled PDSCH is 15kHz. 2^mu_PDSCH, and the UE can receive DCI in downlink time slot n. The index of downlink time slot n can be the index of the subcarrier spacing of the DL BWP through which the UE receives DCI. Here, the UE can receive DCI in time slot floor(n). The PDSCH is received in (2^mu_PDSCH / 2^mu_PDCCH)+K0. Here, floor(n) 2^mu_PDSCH / 2^mu_PDCCH)+K0 can be an index determined based on the subcarrier spacing of the DL BWP through which the PDSCH is transmitted. mu_PDCCH and mu_PDSCH can have values ​​of 0, 1, 2, and 3.

[0183] Figure 12 The diagram illustrates the scheduling of a physical downlink shared channel according to an embodiment of the present disclosure.

[0184] refer to Figure 12 The UE can receive the PDCCH that schedules the PDSCH in downlink time slot (DL time slot) n. The DCI included in the PDCCH can indicate the value of K0 as 3 (K0=3). Here, if the subcarrier spacing of the DL BWP that transmits the PDCCH through it is the same as the subcarrier spacing of the DL BWP that schedules the PDSCH, the UE can be configured to determine that the PDSCH has been scheduled in downlink time slot (n+K0), i.e., time slot (n+3).

[0185] The UE can be configured to determine the time slot for receiving PDSCH using the K0 value, and to determine the symbols from which to transmit PDSCH using the index (S) and length (L) of the starting symbol in the time slot for receiving PDSCH. Within the time slot calculated based on the K0 value, the range of symbols from which to transmit PDSCH can be from symbol S to symbol S+L-1. Symbols from S to S+L-1 can be configured as L consecutive symbols.

[0186] The UE may additionally receive downlink slot aggregation configured from the base station. Here, the downlink slot aggregation can have values ​​of 2, 4, and 8. When the UE receives the configured downlink slot aggregation, the UE can receive PDSCH in consecutive slots based on the slot obtained from the value of K0, according to the slot aggregation value.

[0187] When the UE receives DCI formats 1_0, 1_1, and 1_2 as the DCI used for scheduling PUCCH, the UE can send the PUCCH scheduled by the DCI to the base station. Here, the PUCCH may include HARQ-ACK information. The "PDSCH-to-HARQ_feedback timing indicator" field included in DCI formats 1_0, 1_1, and 1_2 can indicate a K1 value, which is information about the time slot in which the scheduled PUCCH can be sent. K1 can have a non-negative integer value. DCI format 1_0 can indicate one of {0, 1, 2, 3, 4, 5, 6, 7} as the K1 value. The K1 value that can be indicated in DCI formats 1_1 and 1_2 can be configured by a higher layer, or the configured K1 value can be received by a higher layer. The HARQ-ACK information can correspond to HARQ-ACK information indicating whether the reception of two types of channels was successful. When the UE receives a PDSCH schedule via DCI formats 1_0, 1_1, and 1_2, the first type of HARQ-ACK information can correspond to HARQ-ACK information regarding whether the UE has successfully received the PDSCH. When the DCI received by the UE in DCI formats 1_0, 1_1, and 1_2 indicates the release of the SPS PDSCH, the second type of HARQ-ACK information can correspond to HARQ-ACK information regarding whether the UE has received the DCI indicating the release of the SPS PDSCH.

[0188] The UE can be configured to determine the uplink slot in which to transmit PUCCH including HARQ-ACK information of the first type. The UE can determine the slot for transmitting PUCCH based on the uplink slot that overlaps with the last symbol of the PDSCH from which the HARQ-ACK information is transmitted. For example, if the index of the uplink slot is m, the index of the uplink slot in which the UE transmits PUCCH including HARQ-ACK information could be m+K1. The index of the uplink slot can be a value determined based on the subcarrier spacing of the BWP through which the PUCCH is transmitted. When the UE is configured with downlink slot aggregation, the last symbol of the PDSCH from which it is transmitted can correspond to the last symbol of the PDSCH scheduled from the last slot in the slot from which the PDSCH is received.

[0189] Figure 13 The diagram illustrates the scheduling of the physical uplink control channel according to an embodiment of the present disclosure.

[0190] refer to Figure 13The UE can receive the PDCCH for scheduling the PDSCH in downlink time slot n. In this case, the DCI included in the PDCCH can indicate the value of K0 as 3 and the value of K1 as 2. Furthermore, the subcarrier spacing of the DL BWP for receiving the PDCCH, the subcarrier spacing of the DL BWP for scheduling the PDSCH, and the subcarrier spacing of the UL BWP for transmitting the PUCCH can be the same. Here, the UE can receive the PDSCH in downlink time slot (n+K0), i.e., downlink time slot (n+3). The UE can determine the uplink time slot that overlaps with the last symbol of the PDSCH scheduled in downlink time slot (n+3). Here, the last symbol of the PDSCH scheduled in downlink time slot (n+3) overlaps with the uplink time slot (n+3). Therefore, the UE can transmit the PUCCH including the first type of HARQ-ACK information in uplink time slot (n+3) + K1, i.e., time slot (n+5).

[0191] Additionally, the UE can determine the time slot in which to transmit the PUCCH including the second type of HARQ-ACK information as follows: The UE can determine the uplink time slot that overlaps with the last symbol of the PDCCH corresponding to the second type of HARQ-ACK information transmitted therein as the time slot for transmitting the second type of HARQ-ACK information. When the index of the uplink time slot is m, the UE can transmit the PUCCH including the second type of HARQ-ACK information on the uplink time slot m+K1. Here, the index of the uplink time slot can be determined based on the subcarrier spacing of the UL BWP through which the PUCCH is transmitted.

[0192] Figure 14 The diagram illustrates the scheduling of the physical uplink shared channel and the physical uplink control channel according to an embodiment of the present disclosure.

[0193] refer to Figure 14 The UE can receive a DCI indicating the release of the SPS PDSCH in downlink slot n. Here, the DCI can indicate a value of 3 for K1. The subcarrier spacing of the DL BWP that receives the PDCCH and the subcarrier spacing of the ULBWP that transmits the PUCCH can be the same. Here, the UE can determine the uplink slot that overlaps with the last symbol of the PDCCH received in slot n. The UE can be configured to schedule the PUCCH, including the HARQ-ACK information of the DCI indicating the release of the SPS PDSCH, in uplink slot (n+K1), i.e., slot (n+3).

[0194] When the UE has received DCI formats 0_0, 0_1, and 0_2 as DCIs used for scheduling PUSCH, the UE can send the scheduled PUSCH to the base station. For this purpose, the UE should use the DCI to determine the time slot in which the PUSCH is scheduled, as well as the start index and length (number of symbols) of the symbols within the time slot. The Time Domain Resource Assignment (TDRA) field of DCI formats 0_0, 0_1, and 0_2 can indicate a K2 value as information about the time slot in which the PUSCH is scheduled, and a Start Length Indicator value (SLIV) as information about the index and length of the start symbol in the time slot. Here, K2 can have a non-negative integer value. Here, SLIV can be a value obtained by jointly encoding the values ​​of the index (S) and length (L) of the start symbol in the time slot. Alternatively, SLIV can indicate the values ​​of the index (S) and length (L) of the start symbol in the time slot separately. Here, in the case of normal CP, S can have one of the values ​​0, 1, ..., 13, and L can be one of the natural numbers that satisfy the condition, and here, the value of (S+L) is equal to or less than 14. In the case of extended CP, S can have one of the values ​​0, 1, ..., 11, and L can be one of the natural numbers that satisfy the condition, and here, the value of (S+L) is equal to or less than 12.

[0195] The UE can determine the time slot in which to transmit PUSCH based on the K2 value. Specifically, the UE can determine the time slot in which to transmit PUSCH based on the index of the time slot in which the K2 value and DCI are transmitted, the subcarrier spacing of the DL BWP through which the DCI is transmitted, and the subcarrier spacing of the ULBWP through which the PUSCH is transmitted.

[0196] For example, when the subcarrier spacing of the DL BWP that transmits DCI and the subcarrier spacing of the ULBWP that transmits scheduled PUSCH are the same, and the UE receives DCI in downlink slot n, the UE can transmit PUSCH in uplink slot (n+K2).

[0197] For example, the subcarrier spacing of the DL BWP that transmits DCI is 15 kHz. The subcarrier spacing of the UL BWP that transmits the scheduled PUSCH via the 2^mu_PDCCH is 15kHz. 2^mu_PUSCH, and the UE can receive DCI in downlink time slot n. Here, the index of downlink time slot n can be determined based on the subcarrier spacing of the DL BWP through which DCI is transmitted. Here, the UE can receive DCI in time slot floor(n). PUSCH is transmitted in (2^mu_PUSCH / 2^mu_PDCCH)+K2. The uplink slot index floor(n) can be determined based on the subcarrier spacing of the UL BWP transmitting the PUSCH. 2^mu_PUSCH / 2^mu_PDCCH)+K2. mu_PDCCH and mu_PUSCH can have values ​​of 0, 1, 2, and 3.

[0198] refer to Figure 14 The UE can receive the PDCCH for scheduling the PUSCH in downlink time slot n. The DCI included in the PDCCH can indicate the value of K2 as 3. The subcarrier spacing of the DL BWP that transmits the PDCCH through it and the subcarrier spacing of the UL BWP that transmits the PUSCH through it can be the same. Here, the UE can be configured to determine whether to schedule the PUSCH in uplink time slot (n+K2) or time slot (n+3).

[0199] The UE can determine the time slot for transmitting PUSCH based on the K2 value, and can use the index (S) and length (L) of the starting symbol in the determined time slot to determine the symbols from which PUSCH can be transmitted. Specifically, the symbols from which PUSCH is transmitted in the time slot determined based on the K2 value can correspond to symbols S to S+L-1. Symbols S to S+L-1 can correspond to L consecutive symbols.

[0200] Additionally, the UE can receive uplink slot aggregation configured from the base station. The uplink slot aggregation value can be 2, 4, or 8. When the UE receives the configured uplink slot aggregation, the UE can transmit PUSCH in consecutive slots corresponding to the slot aggregation value, starting from the slot determined based on the K2 value.

[0201] refer to Figures 12 to 14 The UE can use the values ​​of K0, K1, and K2 to determine the time slot in which it transmits scheduled PDSCH, the time slot in which it transmits PUCCH, and the time slot in which it transmits PUSCH. In this specification, the time slot determined when the values ​​of K0, K1, and K2 are 0 can be described as a reference point or reference time slot. That is, in Figure 12 In this context, the reference time slot corresponds to the downlink time slot n in which the PDCCH is received; Figure 13 In the context of the reference slot, the reference slot corresponds to the uplink slot (n+3) that overlaps with the last symbol from which the PDSCH is transmitted; while in the context of the reference slot, the reference slot corresponds to the uplink slot (n+3) that overlaps with the last symbol of the uplink slot from which the PDSCH is transmitted. Figure 14 In this context, the reference time slot can correspond to the uplink time slot n, which overlaps with the last symbol of the PDCCH transmitted from it.

[0202] In this specification, uplink time slots and downlink time slots may be referred to simply as time slots, without distinguishing between them separately. In the following text, it is assumed that the subcarrier spacing of the DL BWP transmitting PDSCH and PDCCH through it, and the subcarrier spacing of the UL BWP transmitting PUSCH and PUCCH through it, are the same.

[0203] To improve the reliability of PDCCH reception, the UE can be configured to receive PDCCH repeatedly from the base station. The reliability of PDCCH reception can be based on the CCE aggregation level (AL) used for PDCCH. For example, the UE can have higher reliability when receiving PDCCH at CCE aggregation level 8 or 16 instead of at CCE aggregation level 1 or 2. In this specification, reception reliability can represent the probability that the UE successfully receives PDCCH.

[0204] The base station can configure the CCE aggregation level and the number of PDCCH candidates monitored by the UE per CCE aggregation level using the UE's control resource set and search space information for receiving PDCCHs. UEs in certain situations, such as those located at the cell edge, may require a high CCE aggregation level for PDCCH reception. However, there may be situations where the control resource set configured by the base station for the UE cannot provide the CCE aggregation level required for PDCCH reception. For example, to support CCE aggregation level 16 for PDCCH reception, the UE's control resource set requires 16 CCEs, i.e., 96 Resource Element Groups (REGs). Here, if the control resource set includes 2 symbols, it can include 96 REGs when at least 48 RBs are allocated on resources in the frequency domain. However, the control resource set may not support CCE aggregation level 16 when the frequency domain bandwidth supported by the UE is narrow, or when the base station configures the UE to use only narrow bandwidth for channel reception. In situations where configuring a high CCE aggregation level is difficult, the base station can configure the UE to repeatedly receive PDCCHs.

[0205] In this specification, PDCCH 1A, PDCCH 1B, etc., can refer to the PDCCH received by the UE by monitoring PDCCH #1A candidates, PDCCH #1B candidates, etc. Furthermore, in this specification, (repeated) PDCCH candidates and (repeated) PDCCH can be described interchangeably.

[0206] In the following text, reference will be made to Figures 15 to 17 This describes in detail the method by which the base station configures the UE to repeatedly receive PDCCH.

[0207] Figure 15 The illustration shows the repeated transmission of PDCCH in different control resource sets according to embodiments of the present disclosure.

[0208] refer to Figure 15 The UE can assume that the PDCCH transmitted in multiple different control resource sets includes the same DCI. Specifically, the UE can do so through the first time slot ( Figure 15 The UE can receive PDCCH 1A by performing monitoring in CORESET A (time slot n) and can receive PDCCH 1A through the second time slot ( Figure 15 The UE receives PDCCH 1B by monitoring in CORESET B (slot (n+1)). Here, the UE can receive a configuration of PDCCHs where PDCCH 1A and PDCCH 1B are PDCCHs that include the same DCI from the base station in advance. The UE can obtain DCI information by independently decoding each of PDCCH 1A and PDCCH 1B. However, if obtaining DCI information fails even after independently decoding PDCCH 1A and PDCCH 1B, the UE can obtain DCI information by combining and decoding PDCCH 1A and PDCCH 1B. In addition to PDCCH 1A and PDCCH 1B as described above, the UE can also receive PDCCH 1C via CORESET C and PDCCH 1D via CORESET D. Furthermore, although in Figure 15 The document already describes how the same DCI can be included in PDCCHs of CORESETs in different time slots (e.g., time slot n and time slot (n+1)). However, multiple CORESETs can be configured in one time slot, and the UE can receive PDCCHs through these multiple CORESETs, with the received PDCCHs potentially including the same DCI. In other words, the first and second time slots can be different time slots or the same time slot. Furthermore, PDCCHs including the same DCI can have the same CCE aggregation level.

[0209] Figure 16 The illustration shows repeated transmission of PDCCH in different search spaces according to embodiments of the present disclosure.

[0210] refer to Figure 16 The base station can be in a CORESET ( Figure 16 In CORESET A, multiple search spaces can be configured for the UE. That is, although a CORESET is configured in the same resource domain for each time slot, the search space for each time slot can be configured in different time resource domains. The UE can assume that the PDCCH transmitted in multiple search spaces includes the same DCI. Since a CORESET corresponds to the same resource domain for each time slot, the length (number of symbols) of the frequency domain and time domain for transmitting the PDCCH in it is the same. The UE can configure multiple search spaces in the first time slot (CORESET A). Figure 16PDCCH 1A is received by monitoring in the search space A of CORESET A in time slot n), and can be received in the second time slot ( Figure 16 The UE receives PDCCH 1B by monitoring in search space B of CORESET A in time slot (n+1). The base station can pre-configure for the UE that the DCI included in PDCCH 1A and PDCCH 1B is the same. The UE can obtain DCI information by decoding each of PDCCH 1A and PDCCH 1B independently. However, when obtaining DCI information fails even after decoding PDCCH 1A and PDCCH 1B independently, DCI information can be obtained by combining and decoding PDCCH 1A and PDCCH 1B. In addition to PDCCH 1A and PDCCH 1B, the UE can also receive PDCCH 1C in search space C and PDCCH 1D in search space D. Furthermore, although in Figure 16 The previous description already outlined how the same DCI can be included in PDCCHs transmitted through search spaces in different time slots (e.g., time slot n and time slot (n+1)). However, multiple search spaces can be configured within a single time slot, allowing the UE to receive PDCCHs through multiple search spaces, and the received PDCCHs can include the same DCI. In other words, the first and second time slots can be different time slots or the same time slot. Furthermore, PDCCHs including the same DCI can have the same CCE aggregation level.

[0211] In this specification, for ease of explanation, a PDCCH containing the same DCI information may be described as a duplicate PDCCH. Additionally, a PDCCH that is sent only once may be included in a duplicate PDCCH. For example, Figure 15 and Figure 16 The PDCCH in the PDCCH is one of which is repeated four times and can be configured as PDCCH 1A, PDCCH 1B, PDCCH 1C and PDCCH 1D.

[0212] When a UE is configured to receive repeated PDCCHs from a base station, the UE can monitor PDCCH candidates that are configured to be received repeatedly and include the same DCI information (e.g., Figure 15 and Figure 16The UE receives PDCCHs (PDCCH #1A, PDCCH #1B, PDCCH #1C, and PDCCH #1D candidates) and can determine whether the DCI included in the received PDCCH has been properly received. The UE can determine whether one, more, or all of the repeated PDCCHs have been successfully received. For example, if a PDCCH is configured to be transmitted four times repeatedly, the UE can perform monitoring only on PDCCH #1A candidate to successfully receive the DCI included in the corresponding PDCCH. Alternatively, the UE can successfully receive the DCI included in the corresponding PDCCH by monitoring PDCCH #1B and PDCCH #1C candidates. Furthermore, the UE can successfully receive the DCI included in the corresponding PDCCH by monitoring PDCCH #1A, PDCCH #1B, PDCCH #1C, and PDCCH #1D candidates.

[0213] Figure 17 The illustration shows different repeating PDCCHs overlapping in the time-frequency domain according to an embodiment of the present disclosure.

[0214] The base station can configure the UE to receive the first repeated PDCCH by monitoring the first repeated PDCCH candidate in the first CORESET and search space. Similarly, the base station can configure the UE to receive the second repeated PDCCH, the third repeated PDCCH, and the fourth repeated PDCCH by monitoring the second repeated PDCCH candidate, the third repeated PDCCH candidate, and the fourth repeated PDCCH candidate in the second CORESET and search space, the third repeated PDCCH candidate, and the fourth repeated PDCCH candidate, respectively.

[0215] refer to Figure 17The UE can receive the first repeated PDCCH by monitoring repeated PDCCH#1 candidates (first repeated PDCCH candidates) in the first CORESET and search space. The first repeated PDCCH can be configured to be transmitted four times. The four repeated PDCCHs can correspond to the PDCCHs transmitted on PDCCH#1A candidates in slot n, PDCCH#1B candidates in slot (n+1), PDCCH#1C candidates in slot (n+2), and PDCCH#1D candidates in slot (n+3). The UE can receive the second repeated PDCCH by monitoring repeated PDCCH#2 candidates (second repeated PDCCH candidates) in the second CORESET and search space. The second repeated PDCCH can be configured to be transmitted twice. The PDCCHs transmitted twice can be the PDCCHs transmitted on PDCCH#2A candidates in slot (n+1) and PDCCH#2B candidates in slot (n+2). The UE can receive the third repeated PDCCH by monitoring repeated PDCCH#3 candidates (third repeated PDCCH candidates) in the third CORESET and search space. The third repeated PDCCH can be configured to be received non-repeatingly in time slot (n+2). Here, the received PDCCH may include a DCI in a DCI format with a CRC scrambled by C-RNTI, MCS-C-RNTI, CS-RNTI, SFI-RNTI, INT-RNTI, or CI-RNTI. Here, the received DCI format may include DCI formats 0_0, 0_1, 0_2, 1_0, 1_1, 1_2, 2_0, 2_1 to 2_4.

[0216] refer to Figure 17There may be resource overlap in the PDCCHs transmitted in different CORESETs and search spaces that the UE receives from the base station in its configuration. Specifically, the base station can configure the UE to repeatedly monitor repeating PDCCH#1 candidates (first repeating PDCCH candidates) in time slots n, n+1, n+2, and n+3. The base station can configure the UE to repeatedly monitor repeating PDCCH#2 candidates (second repeating PDCCH candidates) in time slots n+1 and n+2. That is, the UE should monitor repeating PDCCH#1 candidates and repeating PDCCH#2 candidates in time slots n+1 and n+2, and receive the corresponding PDCCHs. Here, when the time-frequency resource fields of time slots (n+1) and (n+2) in which PDCCH#1 is transmitted overlap with the resources for transmitting PDCCH#2, the UE can be configured not to distinguish whether the PDCCH received in time slots n+1 and n+2 after performing its monitoring is a repeating PDCCH#1 or a repeating PDCCH#2. Therefore, even if the UE has successfully received a duplicate PDCCH, a question may arise regarding whether the received PDCCH should be identified as a duplicate PDCCH#1 or a duplicate PDCCH#2 when decoding the DCI information included in the received duplicate PDCCH. Alternatively, the base station can configure the UE to monitor for non-duplicate duplicate PDCCH#3 candidates (third duplicate PDCCH candidates) in time slot (n+2) to receive the corresponding PDCCH. Here, the UE can monitor duplicate PDCCH#1 candidates, duplicate PDCCH#2 candidates, and PDCCH#3 candidates in time slot (n+2) and receive the corresponding PDCCH. When the time-frequency resource fields of time slot (n+2) in which PDCCH#1, PDCCH#2, and PDCCH#3 are transmitted overlap, the UE can be configured not to distinguish whether the PDCCH received in time slot (n+2) is a duplicate PDCCH#1, a duplicate PDCCH#2, or a duplicate PDCCH#3. Therefore, even if the UE has successfully received a duplicate PDCCH, a question may arise regarding whether the UE should identify the received PDCCH as duplicate PDCCH#1, duplicate PDCCH#2, or duplicate PDCCH#3 when decoding the DCI information included in the received duplicate PDCCH. The aforementioned overlap of time-frequency resource fields can include cases where the resource fields in which PDCCHs are transmitted completely overlap. In other words, this situation can include cases where the CCEs in which each PDCCH is transmitted completely overlap.

[0217] The following section describes a situation where the UE cannot determine whether the received PDCCH corresponds to a duplicate PDCCH due to the overlap of time and frequency resource domains, i.e., the ambiguity of the PDCCH.

[0218] Figure 18The illustration depicts a problem that occurs when determining the time slots in which the physical downlink shared channel is scheduled, according to an embodiment of the present disclosure.

[0219] Figure 18 The diagram illustrates the issue regarding the value of K0 mentioned above. (Reference) Figure 18 (a) When the DCI successfully received by the UE is included in the first repeated PDCCH (configured to be transmitted repeatedly four times), the UE can be configured to regard the time slot (n+3) in which the last repeated PDCCH of the first repeated PDCCH is transmitted as the reference time slot, and apply the value of K0 from that reference time slot. That is, the UE can be configured to determine that the PDSCH is scheduled to be transmitted in time slot (n+3) + K0(n+3+3), i.e., time slot (n+6). Figure 18 In (b), when the DCI successfully received by the UE is included in the second repeated PDCCH (configured to be transmitted twice), the UE can be configured to consider the time slot (n+2) in which the last repeated PDCCH in which the second PDCCH is transmitted as the reference time slot, and apply the value of K0 from that reference time slot. That is, the UE can be configured to determine that the PDSCH is scheduled to be transmitted in time slot (n+5), which is time slot (n+2) + K0(n+2+3). Therefore, different results may occur depending on which repeated PDCCH the DCI successfully received by the UE belongs to.

[0220] Figure 19 The illustration depicts a problem that occurs when determining the time slots for scheduling the physical uplink shared channel and the physical uplink control channel, according to an embodiment of the present disclosure.

[0221] Figure 19 The diagram illustrates the issue regarding the values ​​of K1 and K2 mentioned above.

[0222] First, refer to Figure 19 Describe the question regarding the value of K1. Figure 19 The PUCCH may include HARQ-ACK information for the DCI used to indicate the release of SPSPDSCH. (See reference) Figure 19 (a) When the DCI successfully received by the UE is included in the first repeated PDCCH (configured to be transmitted repeatedly four times), the UE can be configured to regard the time slot (n+3) in which the last repeated PDCCH of the first repeated PDCCH is transmitted as the reference time slot, and apply the K1 value from that reference time slot. That is, the UE can be configured to determine that the PUCCH is scheduled to be transmitted in time slot (n+5) as time slot (n+3) + K1(n+3+2). Reference Figure 19(b) When the DCI successfully received by the UE is included in the second repeated PDCCH (configured to be transmitted twice), the UE can be configured to regard the time slot (n+2) in which the last repeated PDCCH in which the second repeated PDCCH is transmitted as the reference time slot, and can apply the K1 value from that reference time slot. That is, the UE can be configured to determine that the PUCCH is scheduled to be transmitted in the time slot (n+4) which is time slot (n+2) + K2(n+2+2). Therefore, different results may occur depending on which repeated PDCCH the DCI successfully received by the UE belongs to.

[0223] Next, we will refer to Figure 19 Describe the question regarding the value of K2. (Reference) Figure 19 (a) When the DCI successfully received by the UE is included in the first repeated PDCCH (configured to be transmitted repeatedly four times), the UE can be configured to regard the time slot (n+3) in which the last repeated PDCCH in which the first PDCCH is transmitted as the reference time slot, and apply the K2 value from that reference time slot. That is, the UE can be configured to determine that the PUSCH is scheduled to be transmitted in time slot (n+3) + K2(n+3+2), i.e., time slot (n+5). Reference Figure 19 In (b), when the DCI successfully received by the UE is included in the second repeated PDCCH (configured to be transmitted twice), the UE can be configured to consider the time slot (n+2) in which the last repeated PDCCH in which the second repeated PDCCH is transmitted as the reference time slot, and apply the K2 value from that reference time slot. That is, the UE can be configured to determine that the PUSCH is scheduled to be transmitted in time slot (n+4), which is time slot (n+2) + K2(n+2+2). Therefore, different results may occur depending on which repeated PDCCH the DCI successfully received by the UE belongs to.

[0224] Figure 20 The illustration shows time slot determination based on a dynamic time slot format indicator according to an embodiment of the present disclosure.

[0225] Figure 20 The diagram illustrates the problem that occurs when applying a slot indicated by a Dynamic Slot Format Indicator (SFI) and the symbol configuration (uplink, downlink, or flexible) of the indicated slot.

[0226] The DCI format 2_0 included in the first repeated PDCCH transmitted by the base station may include a dynamic SFI. The UE may determine the time slot and its symbol configuration based on the dynamic SFI. Here, the time slot indicated by the dynamic SFI may be a specific number of time slots starting from the last time slot among the time slots in which repeated PDCCHs are transmitted. Here, the specific number may be configured by RRC. For example, refer to Figure 20 The base station can configure the UE to repeatedly receive the first repeated PDCCH in time slots n, (n+1), (n+2), and (n+3). The UE can be configured to apply symbol configurations indicated by dynamic SFI to the four time slots starting from time slot (n+3), where time slot (n+3) is the last time slot in which the first repeated PDCCH is transmitted. Figure 20 The text describes applying a time slot configuration indicated by a dynamic SFI starting from the last time slot in which the first duplicate PDCCH is transmitted. However, the application of the time slot configuration indicated by a dynamic SFI can also start from the first time slot in which the first duplicate PDCCH is transmitted, from a time slot after the first time slot configured by a higher layer, or from a time slot after the last time slot configured by a higher layer.

[0227] Figure 21 The illustration depicts a problem that occurs when determining a timeslot based on a dynamic timeslot format indicator, according to an embodiment of the present disclosure.

[0228] Figure 21 The diagram illustrates a problem that occurs when applying a timeslot indicated by a dynamic SFI and the symbol configuration of the indicated timeslot. (Reference) Figure 21 (a) When the DCI of format 2_0, which has been successfully received by the UE, is included in the first repeated PDCCH (configured to be transmitted repeatedly four times), the UE can be configured to apply the symbol configuration indicated by the dynamic SFI starting from time slot (n+3), which is the last time slot among the time slots in which the first repeated PDCCH is transmitted. (See reference) Figure 21 (b) When the DCI of format 2_0 successfully received by the UE is included in the second repeated PDCCH (configured to be transmitted twice), the UE can be configured to apply the symbol configuration indicated by the dynamic SFI starting from time slot (n+2), which is the last time slot among the time slots in which the second repeated PDCCH is transmitted. Therefore, the time slot for applying the symbol configuration indicated by the dynamic SFI can vary depending on which repeated PDCCH the DCI successfully received by the UE belongs to.

[0229] Figure 22 The illustration shows the determination of time slots based on downlink preemption indication according to an embodiment of the present disclosure.

[0230] Figure 22 The diagram illustrates a problem concerning resources in the time-frequency domain indicated by the downlink (DL) preemption indication.

[0231] The base station may include a DCI format 2_1 in the first repeated PDCCH and send it to the UE. The DCI format 2_1 includes a DL preemption indication. The UE may determine reference DL resources to determine the resources in the time-frequency domain indicated by the DL preemption indication. The DL preemption indication may indicate some reference DL resources in the time-frequency domain.

[0232] In the following text, reference will be made to Figure 22 This describes a method for the UE to determine a reference DL resource. Here, the transmission period of the first repeated PDCCH, including the DL preemption indication, can be 8 time slots. Additionally, for ease of explanation, the first repeated transmission ( Figure 22 The transmission of repeated PDCCHs in time slots n to n+3 is described as the transmission during the first period, while the second repeated transmission ( Figure 22 The transmission of repeated PDCCHs in time slots n+8 to n+11 is described as the transmission during the second period. That is, the first period can correspond to time slots n to n+3, while the second period can correspond to time slots (n+8) to n+11.

[0233] refer to Figure 22 (a) When the UE receives the first repeated PDCCH including the DL preemption indication transmitted during the second cycle, the reference DL resource for the DL preemption indication may include the resource preceding the first symbol of the first repeated PDCCH within the first repeated PDCCH of the second cycle (i.e., in...). Figure 22 (a) The first symbol of the first repeated PDCCH in the first repeated PDCCH of the first cycle, which is exactly before the first symbol of the first repeated PDCCH in the first time slot (n+7) of the first time slot (n+8). Figure 22 (a) The first symbol of time slot n) Figure 22 (a) Slots n to (n+7)). In other words, the reference DL resource for DL ​​preemption indication may include P slots or P slots exactly before the first symbol of the first repeated PDCCH in the first repeated PDCCH of the second cycle. N slot symb N symbols. P is the transmission period of the first repeated PDCCH, and P can be 8. slot symb Indicates the number of symbols that make up a time slot. According to Figure 22(a) The reference DL resource corresponds to a resource that is a predetermined time interval away from the last slot in which the first repeated PDCCH is transmitted. Therefore, rapid transmission of the DL preemption indication may not be possible.

[0234] refer to Figure 22 (b) When the UE receives the first repeated PDCCH including the DL preemption indication transmitted during the second cycle, the reference DL resource for the DL preemption indication may include the resource preceding the first symbol of the last repeated PDCCH within the first repeated PDCCH of the second cycle (i.e., in...). Figure 22 In (b), the first symbol of the last repeated PDCCH in the first repeated PDCCH of the first cycle is located exactly before the first symbol of the first repeated PDCCH in the first repeated PDCCH of the first cycle (n+11). Figure 22 (b) First symbol of time slot (n+3) Figure 22 (b) Slots (n+3) to (n+10)). In other words, the reference DL resource for DL ​​preemption indication may include P slots or P slots preceding the first symbol of the last repetition of the PDCCH in the first repetition of the second cycle. N slot symb N symbols. P is the transmission period of the first repeated PDCCH, and P can be 8. slot symb Indicates the number of symbols that make up a time slot. According to Figure 22 (a) and Figure 22 (b) The reference DL resource includes the slot or symbol in which the UE receives repeated PDCCH (i.e., Figure 22 In (a), time slots n to (n+3), and Figure 22 (b) in time slots (n+3) and (n+8) to (n+10). When the UE fails to receive both PDCCH and PDSCH simultaneously through a symbol, the UE can be configured to exclude the symbol or time slot in the reference downlink resource from transmitting duplicate PDCCH.

[0235] refer to Figure 22 (c) When the UE receives the first repeated PDCCH including the DL preemption indication transmitted during the second cycle, the reference DL resources for the DL preemption indication may include Q time slots, Q N slot symb Q symbols, or exactly Q symbols preceding the first symbol of the first repeated PDCCH in the first repeated PDCCH of the second cycle. Q can indicate the difference between the transmission period of the repeated PDCCH including the DL preemption indication and the time slot used for repeated transmission, or a value configured by the base station through a higher layer. Reference Figure 22 (c) The transmission period of the repeated PDCCH corresponds to 8 time slots and the number of time slots used for repeated transmission is 4, so Q can have a value of 4 (8-4). N slot symb Indicates the number of symbols included in a time slot. According to Figure 22 (c) can exclude, for example Figure 22 As shown in (a) and (b), the reference DL resource includes slots or symbols configured for repeated transmission of PDCCH.

[0236] Figure 23 The illustration depicts a problem that occurs when a time slot is determined according to a DL preemption instruction, according to an embodiment of the present disclosure.

[0237] In the following text, reference will be made to Figure 23 This describes a problem that occurs when the UE determines a resource in the time-frequency domain indicated by the DL preemption indication. For ease of explanation, it is assumed that the reference DL resource is as follows: Figure 22 As described in (a).

[0238] refer to Figure 23 In (a), the first repeated PDCCH, including DCI format 2_1, sent from the base station to the UE, can be configured to be sent repeatedly four times. In this case, as referenced... Figure 22 As described in (a), the reference DL resource may include symbols for slots n to n+7. Figure 23 In (b), the second repeated PDCCH, which includes DCI format 2_1, sent from the base station to the UE, can be configured to be transmitted twice. Here, the UE can determine the reference DL resource based on the second repeated reception time slot (n+9) configured with the second repeated PDCCH. The number of time slots or symbols included in the reference DL resource can be determined based on the transmission period of the second repeated PDCCH. That is, the reference DL resource can include symbols from time slots n+1 to n+8 (see [reference]). Figure 22 (a) Therefore, it is possible that the reference DL resource may be determined differently depending on which repeating PDCCH the DCI successfully received by the UE belongs to.

[0239] Figure 24 The illustration shows a time slot determined according to an uplink cancellation instruction, based on an embodiment of the present disclosure.

[0240] refer to Figure 24The first repeated PDCCH sent by the base station to the UE may include a DCI of DCI format 2_4, which includes an uplink (UL) cancellation indication. The UE can determine reference uplink (UL) resources to determine the resources in the time-frequency domain indicated by the UL preemption indication. The UL cancellation indication may indicate some resources in the time-frequency domain of reference UL resources.

[0241] refer to Figure 24 It can be based on the last symbol of the last PDCCH in the first repeated transmission of the first repeated PDCCH, including the UL cancellation indication. Figure 24 The reference UL resource is determined by the time slot (n+3) in the time slot. Specifically, the reference UL resource may include Y symbols following the last symbol after Tproc + X symbols. Here, Tproc can be a value determined based on the processing time, and X can be a value configured by a higher layer. Y can be a value configured by a higher layer or a value determined based on the transmission cycle of the first repeated PDCCH. Figure 24 Tproc=2, X=1, and Y=4, and here, the units of Tproc, X, and Y values ​​can correspond to symbolic units.

[0242] Figure 25 The diagram illustrates the problem that occurs when a timeslot is determined based on an uplink cancellation instruction.

[0243] Figure 25 The diagram illustrates the problem that occurs when the UE interprets the resource in the time-frequency domain indicated by the UL cancellation instruction.

[0244] refer to Figure 25 (a), as referenced Figure 24 As described, the reference UL resource (time slots (n+7) to (n+10)) can be determined. That is, the last symbol of the last PDCCH of the first repeated transmission configured with the first repeated PDCCH is the symbol of time slot (n+3). Therefore, the Y symbols following the Tproc+X symbols starting from the last symbol of time slot (n+3) can be determined as the reference UL resource. Figure 25(b) The second repeated PDCCH sent by the base station to the UE may include a DCI of DCI format 2_4, which includes a UL cancellation indication. Here, the second repeated PDCCH may be configured to repeat twice. The UE may determine the reference UL resource based on the last symbol of the last repeated PDCCH in the first repeated interval region configured to send the second repeated PDCCH. That is, the last symbol of the last repeated PDCCH in the first repeated interval region of the second repeated PDCCH is the symbol of time slot (n+2). Therefore, the UE may determine the Y symbols following Tproc+X symbols starting from the last symbol of time slot (n+2) as the reference UL resource. Therefore, it is possible that the reference UL resource may be determined differently depending on which repeated PDCCH the DCI successfully received by the UE belongs to.

[0245] The following describes a method for resolving the aforementioned PDCCH ambiguity. Specifically, it describes a method for determining which of several different repeated PDCCHs a DCI received by the UE belongs to. Furthermore, the UE can determine which repeated PDCCH the received DCI is included in and send a HARQ-ACK to that PDCCH to the base station. That is, the UE can send a HARQ-ACK to the base station for the PDCCH determined according to the method described later. Here, the HARQ-ACK sent by the UE to the base station can be the first type HARQ-ACK and / or the second type HARQ-ACK described above.

[0246] i) First Method

[0247] To distinguish between different repeating PDCCHs, the base station can add the necessary information for differentiation to the DCI and transmit this information. Upon successfully receiving a repeating PDCCH, the UE can determine which repeating PDCCH was successfully received based on the information added to the DCI. In this case, the information used to distinguish between different repeating PDCCHs may include at least one of the following:

[0248] The DCI can include information about the number of times the repeated PDCCH has been sent as primary information. In other words, the DCI can include a value indicating how many times the repeated PDCCH has been sent.

[0249] For example, when the number of retransmissions of the repeated PDCCH sent by the base station to the UE is 4, the DCI may include information (value) indicating the number of retransmissions (4 times) or information (value) that can infer the number of retransmissions.

[0250] As another example, when the first repeated PDCCH received by the UE is configured to be transmitted four times and the second repeated PDCCH is configured to be transmitted twice, it is possible that the first and second repeated PDCCHs completely overlap in the time-frequency domain resources of a predetermined time slot. Here, the DCI may include an indicator for distinguishing the first and second repeated PDCCHs. When there are L types of repeated PDCCHs, the DCI can use ceil(log2(L)) bits to indicate the type of repeated PDCCH. ceil(x) is a function representing the smallest integer not less than x. Specifically, when the repeated PDCCHs correspond to two types of repeated PDCCHs, namely the first and second repeated PDCCHs, the information included in the DCI for distinguishing the repeated PDCCHs can correspond to an indicator of size ceil(log2(2)) bits (i.e., 1 bit). A 1-bit indicator value of "0" indicates a second repeated PDCCH that is transmitted twice, while a 1-bit indicator value of "1" indicates a first repeated PDCCH that is transmitted four times. Generally, the UE can obtain the number of completely overlapping repeated PDCCHs in the time-frequency domain resources within a predetermined timeslot. If the number of overlapping repeated PDCCHs is X, the required information can be represented by a size of ceil(log2(X)). Each code point of ceil(log2(X)) bits indicates the number of times the overlapping repeated PDCCHs are transmitted. For example, the lowest code point value can indicate the number of times the PDCCH with the lowest number of repetitions among the repeated PDCCHs configured for the UE is transmitted. Here, the code point values ​​can indicate the number of times the repeated PDCCHs are transmitted in ascending order.

[0251] The second information included in the DCI may be information (a value) indicating the ID of the CORESET corresponding to the repeating PDCCH. For example, when a first repeating PDCCH is transmitted in a first CORESET and a second repeating PDCCH is transmitted in a second CORESET, it is possible that the first and second repeating PDCCHs completely overlap in the time-frequency resource domain within a predetermined time slot. Here, the DCI may include an indicator for distinguishing between the first and second repeating PDCCHs. Specifically, when the repeating PDCCH is of two types, namely a first repeating PDCCH and a second repeating PDCCH, the DCI may include an indicator of size 1 bit to distinguish between the first and second repeating PDCCHs. If the value of the 1-bit indicator is "0", it can indicate the first repeating PDCCH transmitted in the first CORESET, and if the value of the 1-bit indicator is "1", it can indicate the second repeating PDCCH transmitted in the second CORESET. Generally, the UE can obtain the number of CORESETs corresponding to repeating PDCCHs that completely overlap in the time-frequency domain resources within a predetermined time slot. If the number of overlapping repeated PDCCHs is X, the information included in the DCI can be ceil(log2(X)) bits in size. Each code point indicated by ceil(log2(X)) bits can indicate the CORESET ID corresponding to the overlapping repeated PDCCH. For example, the lowest value of the code point can indicate the lowest ID among the CORESET IDs corresponding to the overlapping repeated PDCCHs. The values ​​of the code points can indicate the CORESET IDs in ascending order. The CORESET ID is a value configured by a higher layer, and the base station can send CORESET information including the CORESET ID to the UE.

[0252] The third information included in the DCI can be information (value) indicating the search space ID corresponding to the repeating PDCCH. For example, when a first repeating PDCCH is transmitted in a first search space and a second repeating PDCCH is transmitted in a second search space, it is possible that the first and second repeating PDCCHs completely overlap in the time-frequency resource domain of a predetermined time slot. Here, the DCI can include an indicator for distinguishing between the first and second repeating PDCCHs. When repeating PDCCHs are configured with two types of PDCCHs, namely the first and second repeating PDCCHs, the DCI can include an indicator of size 1 bit to distinguish between the first and second repeating PDCCHs. Specifically, if the value indicated by the 1-bit indicator is "0", it can indicate the first repeating PDCCH corresponding to the first search space, and if the value of the indicator is "1", it can indicate the second repeating PDCCH corresponding to the second search space. Generally, the UE can obtain the number of search spaces corresponding to repeating PDCCHs that completely overlap in the time-frequency domain resources of a predetermined time slot. If the number of search spaces corresponding to overlapping repeated PDCCHs is X, then the information included in the DCI can have a size of ceil(log2(X)) bits. Each code point indicated by ceil(log2(X)) bits can indicate the search space ID corresponding to the overlapping repeated PDCCH. For example, the lowest value of the code point can indicate the lowest ID among the search space IDs corresponding to the overlapping repeated PDCCHs. The values ​​of the code points can represent the search space IDs in ascending order. The search space ID is a value configured by a higher layer, and the base station can send search space information including the search space ID to the UE.

[0253] The fourth information included in the DCI can be information (value) indicating the repeated PDCCH ID corresponding to the repeated PDCCH. For example, when the first repeated PDCCH has a first repeated PDCCH ID and the second repeated PDCCH has a second repeated PDCCH ID, it is possible that the first and second repeated PDCCHs completely overlap in the time-frequency resources of a predetermined time slot. Here, the DCI can include an indicator for distinguishing between the first and second repeated PDCCHs. When repeated PDCCHs are configured with two types of PDCCHs, namely the first and second repeated PDCCHs, the DCI can include an indicator of size 1 bit to distinguish between the first and second repeated PDCCHs. Specifically, if the value indicated by the 1-bit indicator is "0", it can indicate the first repeated PDCCH corresponding to the first search space, and if the value of the indicator is "1", it can indicate the second repeated PDCCH corresponding to the second search space. Generally, the UE can obtain the number of repeated PDCCH IDs corresponding to repeated PDCCHs that completely overlap in the time-frequency domain resources of a predetermined time slot. If the number of duplicate PDCCH IDs corresponding to overlapping duplicate PDCCHs is X, then the information included in the DCI can have a size of ceil(log2(X)) bits. Each code point indicated by ceil(log2(X)) bits can indicate the duplicate PDCCH ID corresponding to the overlapping duplicate PDCCHs. The lowest value of the code point can indicate the duplicate PDCCH ID among the IDs of the overlapping duplicate PDCCHs. The values ​​of the code points can represent the duplicate PDCCH IDs in ascending order. The duplicate PDCCH ID can be a value configured through higher layers. For example, based on search space information sent from the base station to the UE, the aggregation level and the number of duplicate PDCCH candidates monitored by the UE per CCE aggregation level can be configured. In addition, a unique duplicate PDCCH ID can be configured for each duplicate PDCCH candidate monitored by the UE. The duplicate PDCCH ID can be a value obtained by the UE based on CORESET information and / or search space information received from the base station. For example, based on search space information, a CCE aggregation level and the number of duplicate PDCCH candidates monitored by the UE per CCE aggregation level are configured, and a lower CCE aggregation level can be mapped to the lowest duplicate PDCCH ID. Furthermore, CCE aggregation levels and duplicate PDCCH IDs can be mapped sequentially to each other. If the base station configures the UE to monitor multiple duplicate PDCCH candidates at the same CCE aggregation level, the duplicate PDCCH ID can be determined based on at least one value of the CCE index, REG index, or PRB index to which the duplicate PDCCH is mapped.A duplicate PDCCH ID can correspond to at least one of the CCE, REG, and PRB indexes to which the PDCCH is mapped, and can be mapped in ascending order. A duplicate PDCCH ID can also correspond to a search space ID and can be mapped in ascending order. Additionally, a duplicate PDCCH ID can correspond to a CORESETID and can be mapped in ascending order.

[0254] The fifth information included in the DCI can be an index (value) indicating the time slot or symbol from which the transmission of the repeating PDCCH begins. For example, a first repeating PDCCH can be transmitted from time slot n, and a second repeating PDCCH can be transmitted from time slot (n+1). Since the transmission of the first and second repeating PDCCHs begins in different time slots, the fifth information can be the index of the time slot from which the transmission of the first and second repeating PDCCHs begins. A first repeating PDCCH can be transmitted from symbol m of a specific time slot, and a second repeating PDCCH can be transmitted from symbol m+1 of the specific time slot. Since the transmission of the first and second repeating PDCCHs begins in different symbols, the fifth information can be the index of the symbol from which the transmission of the first and second repeating PDCCHs begins.

[0255] The sixth information included in the DCI can be an index (value) indicating the time slot or symbol at which the transmission of the repeated PDCCH ends. For example, the transmission of the first repeated PDCCH can start in time slot n and end in time slot (n+3), while the transmission of the second repeated PDCCH can start in time slot (n+1) and end in time slot (n+2). Since the transmissions of the first and second repeated PDCCHs end in different time slots, the sixth information can be the index of the time slot at which the transmissions of the first and second repeated PDCCHs end. The transmission of the first repeated PDCCH can start in symbol m of a specific time slot and end in symbol m+3 of that specific time slot, while the transmission of the second repeated PDCCH can start in symbol m+1 of a specific time slot and end in symbol m+2 of that specific time slot. Since the transmissions of the first and second repeated PDCCHs end in different symbols, the sixth information can be the index of the symbol at which the transmissions of the first and second repeated PDCCHs end.

[0256] Since the size of the bits representing the fifth and sixth information may be finite, the index of the slot or symbol indicated by the fifth and sixth information can be information (values) obtained after performing a modulo operation. For example, if the finite bit size is N bits, the remainder obtained by dividing the slot index by 2^N (slot index mod 2^N) can be included in the DCI. The method for determining N is as follows. In cases where the UE should distinguish between different repeated PDCCHs, the UE can obtain the number of slots in which the transmission of different repeated PDCCHs begins. For example, when the transmission of the first repeated PDCCH begins in slot n, the transmission of the second repeated PDCCH begins in slot (n+1), and the first and second repeated PDCCHs completely overlap in the resources of a predetermined time-frequency domain of a slot, the UE can be configured to determine that the number (X) of slots in which the repeated PDCCHs begin is two. In this case, N can be obtained by calculating N = ceil(log2(X)).

[0257] In multiple different repeating PDCCHs, overlapping time slots may occur depending on the monitoring period and offset. In this case, adding a separate field to the DCI to address the problem caused by overlapping time slots may increase overhead. As mentioned above, using repeating PDCCHs and thus increasing DCI overhead is inefficient when radio channel conditions are poor (such as cell-edge UEs). Therefore, a method for solving this problem will be described below.

[0258] ii) Second method

[0259] The second method involves obtaining information for distinguishing overlapping duplicate PDCCHs by reinterpreting one or more fields included in an existing DCI. When a UE needs to distinguish a successfully received duplicate PDCCH from different duplicate PDCCHs, the UE can distinguish the duplicate PDCCH by reinterpreting one or more fields included in the successfully received PDCCH's DCI.

[0260] The field used for reinterpretation can be the Redundancy Version (RV) field. That is, the UE can obtain the information needed to distinguish a duplicate PDCCH from different duplicate PDCCHs from the RV field of the DCI. Specifically, the UE can distinguish different duplicate PDCCHs by assuming that the value of the RV field is a specific value (e.g., 0).

[0261] The field used for reinterpretation can be the field used to send the TPC command. That is, the UE can obtain the information needed to distinguish a repeating PDCCH from different repeating PDCCHs from the field used to send the TPC command. Specifically, the UE can distinguish different repeating PDCCHs by assuming that the value of the TPC command field is a specific value (e.g., 0 dB).

[0262] The field used for reinterpretation can be the Downlink Assignment Index (DAI) field. That is, the UE can obtain the information needed to distinguish a repeating PDCCH from different repeating PDCCHs from the DAI field. Specifically, the UE can distinguish different repeating PDCCHs by assuming a specific DAI value as a specific value. For example, since the UE cannot know the DAI value, it can assume the DAI value to be the lowest or highest value. Furthermore, since the UE cannot know the DAI value, it may not perform HARQ-ACK multiplexing based on the DAI.

[0263] Clearly, fields other than those mentioned above can be used to distinguish different repeating PDCCHs. In this case, the fields used to distinguish different repeating PDCCHs can be configured at a higher level. Furthermore, only some bits of this field can be used for reinterpretation, while the remaining bits can be used for their existing purpose. In this case, some bits can correspond to the most significant bit (MSB).

[0264] iii) Third method

[0265] The third method corresponds to the method of distinguishing different repeating PDCCHs by using CRC instead of adding a separate field to the DCI or reinterpreting the existing DCI field as described in the first and second methods above. That is, information for distinguishing different repeating PDCCHs can be delivered to the UE using a DCI scrambled with different CRC values. Specifically, the DCI can be scrambled using a specific RNTI value as the CRC, depending on the purpose. The UE can determine whether DCI reception was successful based on the RNTI value and the CRC value of the DCI. Therefore, the base station can generate a separate RNTI (hereinafter referred to as the first RNTI) based on the RNTI value and the information for distinguishing different repeating PDCCHs, and then use the first RNTI as the CRC of the DCI. The UE can compare the CRC value of the received DCI with the first RNTI value to determine whether DCI reception was successful and obtain the information for distinguishing different repeating PDCCHs. For example, if the information for distinguishing different repeating PDCCHs is X bits in size, the base station can generate the first RNTI value by performing an XOR operation on the X bits of the RNTI. Here, the X bits of the RNTI can be either the most significant bit (MSB) or the least significant bit (LSB) of the RNTI. Additionally, the UE can calculate the available first RNTI value. If the information used to distinguish different repeating PDCCHs has a size of X bits, the number of combinations that can be used as the first RNTI corresponds to 0 to 2^X-1 and can have 2^X RNTI values. The UE can compare the CRC of the received DCI with the 2^X first RNTI values ​​to determine the first RNTI value that matches it. If a matching first RNTI value exists, the UE can be configured to identify the information corresponding to the first RNTI value; that is, the information used to distinguish different repeating PDCCHs is included in the DCI.

[0266] iv) Fourth method

[0267] The fourth method corresponds to the method in which the information used to distinguish different repeated PDCCHs is pre-configured in the UE to a specific value. Specifically, the specific value can be the lowest or highest value configured for the UE among the values ​​indicated by the information used to distinguish different repeated PDCCHs.

[0268] The information used to distinguish different repeated PDCCHs can be a value corresponding to the number of times the repeated PDCCH is transmitted. Therefore, when the specific value configured for the UE is the minimum value, the UE can assume that the repeated PDCCH with the lowest number of repetitions among the different repeated PDCCHs is received. When the specific value configured for the UE is the maximum value, the UE can assume that the repeated PDCCH with the highest number of repetitions among the different repeated PDCCHs is received.

[0269] The information used to distinguish different repeating PDCCHs can be the CORESET ID corresponding to the repeating PDCCH. Therefore, when the specific value configured for the UE is the lowest value, the UE can assume that the repeating PDCCH was received on the CORESET with the lowest ID among the CORESETs corresponding to different repeating PDCCHs. When the specific value configured for the UE is the highest value, the UE can assume that the repeating PDCCH was received on the CORESET with the highest ID among the CORESETs corresponding to different repeating PDCCHs.

[0270] The information used to distinguish different repeating PDCCHs can be the search space ID corresponding to the repeating PDCCH. Therefore, when the specific value configured for the UE is the lowest value, the UE can assume that the repeating PDCCH is received in the search space with the lowest ID among the search space IDs corresponding to different repeating PDCCHs. When the specific value configured for the UE is the highest value, the UE can assume that the repeating PDCCH is received in the search space with the highest ID among the search space IDs corresponding to different repeating PDCCHs.

[0271] The information used to distinguish different repeating PDCCHs can be the repeating PDCCH ID corresponding to the repeating PDCCH. Therefore, when the specific value configured for the UE is the lowest value, the UE can assume that the repeating PDCCH with the lowest ID among the repeating PDCCH IDs corresponding to different repeating PDCCHs is received. If the specific value configured for the UE is the highest value, the UE can assume that the repeating PDCCH with the highest ID among the repeating PDCCH IDs corresponding to different repeating PDCCHs is received.

[0272] v) Fifth Method

[0273] The fifth method is for the UE to distinguish different repeated PDCCHs using search space types. Specifically, there may be cases where the first repeated PDCCH corresponds to a first type of search space, the second repeated PDCCH corresponds to a second type of search space, and the first and second types are different from each other. Here, the UE can be configured to determine that a repeated PDCCH has been received in one of the first search space and the second search space. The UE can determine a search space as follows: If the first search space type is a cell common search space and the second search space type is a specific UE search space, then the UE can be configured to determine that a repeated PDCCH has been received in the first search space of the cell common search space type. 。

[0274] Duplicate PDCCHs transmitted in the cell common search space can include system information and paging information, and can schedule PDSCH, PUCCH, and PUSCH. Additionally, duplicate PDCCHs transmitted in the cell common search space can include dynamic SFI, DL preemption indication, and UL cancellation indication that can be sent to a specific UE or a specific UE group. Therefore, duplicate PDCCHs transmitted in the cell common search space can take precedence over duplicate PDCCHs transmitted in a specific UE search space. Furthermore, since duplicate PDCCHs transmitted in the cell common search space can be received by multiple UEs in the cell, each UE can perform different actions when interpreting the DCI by assuming the received duplicate PDCCH as a UE-specific search space. Therefore, to prevent different operations by multiple corresponding terminals, duplicate PDCCHs transmitted in the common cell search space can be given priority.

[0275] The first to fifth methods described above illustrate methods for determining which repeated PDCCH a DCI received by the UE belongs to among different repeated PDCCHs. Below, methods for resolving PDCCH ambiguity will be described without determining whether the DCI received by the UE is included in which repeated PDCCH and without determining whether the DCI correctly received by the UE has been transmitted via repeated PDCCH. Specifically, methods for explicitly or implicitly determining the methods used in the above references will be described. Figures 18 to 20 The method for describing the time points (i.e., reference time slots) of the values ​​of K0, K1, and K2.

[0276] vi) Sixth Method

[0277] The sixth method is for the base station to indicate the index of the time slot or symbol for which the values ​​of K0, K1, and K2 are applied via the DCI. For example, if the index of the time slot or symbol for which the values ​​of K0, K1, and K2 are applied is "n", the base station can include information about "n" in the DCI and send it to the UE. If the information about the index of the time slot or symbol for which the values ​​of K0, K1, and K2 are applied has a size of N bits, the information about "n" can be included in the DCI as a value obtained by performing a modulo operation. Specifically, the information about "n" is the remainder obtained by dividing the index n by 2^N (n mod 2^N) and can be included in the DCI.

[0278] The UE determines the index of the reference time slot or symbol for which the values ​​of K0, K1, and K2 are applied based on the information included in the DCI as follows. A repeated PDCCH successfully received by the UE can be configured to be transmitted in time slot a, time slot a+1, ..., time slot (a+b-1). In this case, "a" is a non-negative integer, and "b" is an integer greater than 0. The UE may assume that PDSCH, PUCCH, and PUSCH cannot be scheduled before the time point at which the last part of the repeated PDCCH is received. That is, the UE may assume that PDSCH, PUCCH, and PUSCH may not be scheduled before time slot (a+b-1), which is the last time slot among the time slots configured to transmit the repeated PDCCH. Therefore, the UE may assume that the time slot preceding time slot (a+b-1) cannot be used as the time point (reference time slot) for applying the values ​​of K0, K1, and K2.

[0279] The DCI sent by the base station to the UE can include a specific value, and the UE can determine the time point that can be used as a reference time slot based on this specific value. For example, if the specific value is "c", the UE can use time slot n+0. 2^N+c, time slot n+1 2^N+c, time slot n+2 2^N+c, ..., time slot n+i 2^N+c is determined as a candidate for a reference time slot that can apply the values ​​of K0, K1, and K2. Here, "c" can be one of 0, 1, ..., 2^N-1. In this case, N can be the bit size of the information indicating a specific value c. The method for selecting one of the multiple candidate reference time slots is as follows. As mentioned above, since the time slot before time slot (a+b-1) cannot be a reference time slot, the UE can determine any of the time slots after time slot (a+b-1) as the reference time slot. For example, among the candidates for reference time slots, the earliest time slot among the subsequent time slots including time slot (a+b-1) can be determined as the reference time slot.

[0280] In the following text, reference will be made to Figure 26 The method for determining the reference time slot is described in detail.

[0281] Figure 26 The illustration shows a method for determining a reference time slot according to an embodiment of the present disclosure.

[0282] refer to Figure 26 (a) N is 2 bits, and the UE receives an indication as a specific value of "c" via DCI, where the value of "c" can be 0. Therefore, the UE can determine the slot candidates that can be used as a reference slot as slot n, slot (n+4), slot (n+8), ..., etc. In this case, since the UE has received the DCI included in the repeated PDCCH transmitted in slots (n+1) and (n+2), the UE can determine slot (n+4) as the reference slot, which is the earliest slot among the subsequent slots including slots (n+1) and (n+2) in the slot candidates. Furthermore, the UE can be configured to apply the values ​​of K0, K1, and K2 based on the determined reference slot.

[0283] refer to Figure 26 (b) N is 3 bits, and the UE receives an indication as a specific value of "c" via DCI, where the value of "c" can be 0. Therefore, the UE can determine the available time slot candidates as time slot n, time slot (n+8), time slot (n+16), ..., etc. In this case, since the UE has received the DCI included in the repeated PDCCH transmitted in time slots (n+1) and (n+2), the UE can determine time slot (n+8) as the earliest time slot among the subsequent time slots including time slots (n+1) and (n+2) in the time slot candidates as the reference time slot. Furthermore, the UE can be configured to apply the values ​​of K0, K1, and K2 based on the determined reference time slot.

[0284] The UE has determined a candidate reference slot based on specific values ​​included in the DCI. However, including information about these specific values ​​in the DCI can be costly. To address this, information about individual specific values ​​might not be included in the DCI. For example, the UE could select slot 0... M+c, Slot 1 M+c, Time Slot 2 M+c, ..., time slot i M+c, ..., etc., are identified as reference slot candidates. In this case, M and c, which are values ​​configured by higher layers, can be non-negative integer values, and in particular, c can be 0.

[0285] vii) Seventh Method

[0286] When a UE needs to determine whether a successfully received repeated PDCCH is the first or second repeated PDCCH, the UE can determine the last time slot of the repeated PDCCH that ends later in time between the first and second repeated PDCCHs as the reference time slot to which the values ​​of K0, K1, and K2 can be applied. The UE can also determine the time slot of the last PDCCH among repeated PDCCHs configured to be transmitted overlapping in the time-frequency resource domain as the reference time slot. In this case, since repeated PDCCHs are transmitted repeatedly according to the transmission period, the last PDCCH can imply the last PDCCH among repeated PDCCHs within a period. In the following text, the reference time slot will be... Figure 27 This will be described in detail.

[0287] Figure 27 The illustration shows a method for determining a reference time slot according to an embodiment of the present disclosure.

[0288] refer to Figure 27 The UE can determine the last time slot in which the first repeated PDCCH is transmitted and the last time slot in which the second repeated PDCCH is transmitted using the CORESET information and search space information configured by the base station. The first repeated PDCCH can be configured to be transmitted in time slots n, (n+1), (n+2), and (n+3) within a cycle. The second repeated PDCCH can be configured to be transmitted in time slots (n+1) and (n+2) within a cycle. The UE can determine the time slot that ends later in time among the time slots in which the first repeated PDCCH is transmitted and the time slots in which the second repeated PDCCH is transmitted as the reference time slot. For example, the first repeated PDCCH is last transmitted in time slot (n+3) within a cycle, while the second repeated PDCCH is last transmitted in time slot (n+2) within a cycle. Therefore, the UE can determine the reference time slot based on time slot (n+3).

[0289] The sixth and seventh methods described above can be applied to the reference. Figures 20 to 25 The description of PDCCH ambiguity. For example, when determining the time slot for applying dynamic SFI or when determining reference uplink resources, the UE needs location information of the time slot or symbol from which the last PDCCH, including the recurring PDCCH from which the successfully received DCI is transmitted, is sent. Here, a method similar to the sixth or seventh method described above can be used to determine the location of the time slot or symbol from which the last PDCCH is sent.

[0290] Specifically, according to the sixth method, the UE can determine a set of candidate time slots or symbols with a predetermined period. Such a set of candidate time slots or symbols can be indicated by the DCI or determined by a higher layer. The UE can determine a time slot or symbol from the set of candidate time slots or symbols with a predetermined period based on the last time slot or symbol from which repeated PDCCHs are transmitted. For example, the UE can select the earliest candidate time slot or symbol from the set of candidate time slots or symbols that include the last time slot or symbol from which repeated PDCCHs are transmitted. The UE can then determine the time slot for applying dynamic SFI or reference uplink resources from the selected time slot or symbol.

[0291] According to the seventh method, the UE can obtain the index of the last time slot or symbol from which the first repeated PDCCH was transmitted and the index of the last time slot or symbol from which the second repeated PDCCH was transmitted. The time slot for applying dynamic SFI or the reference uplink resource can be determined based on the later time slot / symbol from which the first repeated PDCCH was transmitted and the last time slot / symbol from which the second repeated PDCCH was transmitted. As another example, the time slot for applying dynamic SFI or the reference uplink resource can be determined based on the earliest time slot / symbol from which the first repeated PDCCH was transmitted and the last time slot / symbol from which the second repeated PDCCH was transmitted.

[0292] To determine the reference DL resource, the UE needs to transmit the slot or symbol of the first PDCCH from which a repeating PDCCH containing a successfully received DCI is transmitted. Here, a method similar to the sixth or seventh method described above can be used to determine the slot or symbol from which the first PDCCH is transmitted.

[0293] Specifically, similar to the sixth method, the UE can determine a set of candidate time slots or symbols with a predetermined period. The candidate time slots and symbol sets can be indicated by the DCI or determined by a higher layer. The UE can select a time slot or a set of candidate time slots or symbols based on the first time slot or symbol from which repeated PDCCHs are transmitted. For example, the UE can select the last time slot or symbol from the previous time slot or symbol in the candidate time slot or symbol set from which repeated PDCCHs are transmitted. Alternatively, the UE can select a time slot or symbol from the candidate time slot or symbol set preceding the first time slot or symbol from which repeated PDCCHs are transmitted. The UE can determine a reference DL resource based on the selected time slot or symbol.

[0294] Similar to method seven, the UE can obtain the index of the first time slot or symbol from which the first repeated PDCCH is transmitted and the index of the first time slot or symbol from which the second repeated PDCCH is transmitted. Here, the reference DL resource can be determined based on the earliest time slot / symbol from which the first repeated PDCCH is transmitted and the earliest time slot / symbol from which the second repeated PDCCH is transmitted. As another example, the reference DL resource can be determined based on the last time slot / symbol from which the first repeated PDCCH is transmitted and the latest time slot / symbol from which the second repeated PDCCH is transmitted.

[0295] viii) Eighth Method

[0296] The eighth method is a method of sending information about the repeated transmission of a repeated PDCCH by using a specific PDCCH configured for the repeated PDCCH.

[0297] When a UE is configured to receive repeated PDCCHs from a base station, the UE can be configured to monitor and receive specific PDCCHs to explicitly receive information about the repeated transmission of the repeated PDCCHs. Here, the information about the repeated transmission of PDCCHs may include the first time slot (or symbol) in which the transmission of the repeated PDCCH begins and the number of time slots (or symbols) used for the repeated transmission.

[0298] Information regarding the retransmission of PDCCHs can be explicitly included in the DCI included in a particular PDCCH. In this case, the particular PDCCH can be expressed as the active PDCCH, and for ease of explanation, it is described in this specification as the first active PDCCH.

[0299] Information regarding the retransmission of PDCCH can be explicitly included in the DCI included in the first PDCCH from which the retransmission of PDCCH begins. Here, the first PDCCH can be expressed as the active PDCCH, and for ease of explanation, it is described in this specification as the second active PDCCH.

[0300] Information regarding the retransmission of PDCCHs can be explicitly included in the DCI included in the first PDCCH from which the retransmission of PDCCHs begins and in a specific number of retransmissions. Here, the first PDCCH and the specific number of retransmissions can be expressed as active retransmissions of PDCCHs. The first PDCCH and the specific number of retransmissions of PDCCHs can be consecutive retransmissions of PDCCHs.

[0301] The UE can obtain information about the repeated transmission of the aforementioned repeated PDCCH by reinterpreting existing fields that constitute the DCI. In this case, the DCI can schedule PDSCH, PUCCH, and PUSCH. Existing fields may include the TDRA field. For example, the SLIV value indicated by the TDRA field can be reinterpreted. By reinterpreting the SLIV value, the UE can obtain resource information about repeated PDCCHs that are repeatedly transmitted after the first active PDCCH, the second active PDCCH, and the active repeated PDCCH.

[0302] Specifically, the TDRA field of the DCI included in the repeated PDCCH transmitted after the first activated PDCCH, the second activated PDCCH, and the active repeated PDCCH may include the SLIV value used for scheduling PDSCH, PUCCH, and PUSCH. In other words, the UE can obtain the resource information of the repeated PDCCH, as well as the resource information of PDSCH, PUCCH, and PUSCH, based on the TDRA field of the DCI included in the repeated PDCCH transmitted after the first activated PDCCH, the second activated PDCCH, and the active repeated PDCCH. The TDRA fields described in this specification are shown in Table 4.

[0303] [Table 4]

[0304] Figure 28 The illustration shows the activation of the PDCCH and the reception of the repeating PDCCH according to an embodiment of the present disclosure.

[0305] refer to Figure 28 When a UE receives the active PDCCH#1 in time slot n, the UE can expect to transmit PDSCH, PUCCH, and PUSCH in time slot (n+5). Additionally, the UE can expect repeated transmission of the PDCCH for three time slots starting from time slot (n+1). A UE that has received PDCCH#1A in time slot (n+1), PDCCH#1B in time slot (n+2), and PDCCH#1C in time slot (n+3) can obtain SLIV values ​​for the PDSCH, PUCCH, and PUSCH expected to be transmitted in time slot (n+5).

[0306] When the search spaces for different types of UEs completely overlap in the time-frequency resource domain, the UE can perform blind decoding to receive PDCCH in the search space configured for the UE by receiving information about repeated transmissions of repeated PDCCH.

[0307] The base station can send information about the CORESET and information about the search space to the UE. Information about the CORESET will be described below. In this specification, the resources constituting the CORESET may have the same meaning as the resources included in the CORESET.

[0308] The first piece of information about the CORESET can be an index of the PRB or PRB set that constitutes the CORESET from which PDCCH is transmitted. The PRB set can be six consecutive PRBs. The index of the PRB or PRB set can be configured in the form of a bitmap. For example, if the bit value is 1, the PRB or PRB set may correspond to the CORESET used for receiving PDCCH. If the bit value is 0, the PRB or PRB set may not correspond to the CORESET used for receiving PDCCH. The second piece of information about the CORESET can be the number of symbols from which PDCCH is transmitted. Here, the number of symbols can be 1, 2, or 3, and the symbols can be consecutive symbols. The UE can determine the resources through which to transmit PDCCH by receiving information about the CORESET from the base station.

[0309] Specifically, the first information about CORESET can be configured with the PRB index as PRB#(6 n), PRB#(6 n+1), PRB#(6 n+2) and PRB#(6 n+3), PRB#(6 n+4) and PRB#(6 The base station can configure the indices of P PRBs as PRB#0, PRB#1, ..., PRB#(P-1), where P can be a multiple of 6. The PRBs can be continuous or non-contiguous in the frequency domain. The second information about CORESET can correspond to the number (S) of symbols used to transmit the PDCCH, where S can be one of 1, 2, or 3. In other words, the UE can receive resources for PDCCH transmission based on the first and second information configured from the base station.

[0310] The resources corresponding to the P PRBs and S symbols that make up a CORESET can be configured as a Resource Element Group (REG). A REG can include one PRB and one symbol. That is, P P PRBs and S symbols can be configured as P... S REGs. Two, three, or six adjacent REGs can be bundled to form a REG bundle. The method of bundling 2, 3, or 6 REGs can be determined based on the length of the CORESET (number of symbols) and the mapping method (interleaved mapping / non-interleaved mapping).

[0311] When using a non-interleaved mapping method and the length of the CORESET corresponds to one symbol, a REG bundle can be generated by bundling six consecutive REGs in the frequency domain. When using a non-interleaved mapping method and the length of the CORESET corresponds to two symbols, three REGs can be bundled in each symbol, resulting in a total of six REGs (three REGs per symbol). A REG bundle can be generated using 2 symbols. For convenience, when each of the 1 symbols in the 2 symbols is referred to as symbol A and symbol B, the three REGs in symbol A can be consecutive in the frequency domain, and the three REGs in symbol B can also be consecutive in the frequency domain. Furthermore, the three REGs in symbol A and the three REGs in symbol B can reside in the same frequency domain. When using a non-interleaved mapping method and the length of the CORESET corresponds to 3 symbols, it is possible to bundle 2 REGs in each symbol, resulting in a total of 6 REGs (2 REGs per symbol). A REG bundle is generated using 3 symbols. For convenience, when each of the 3 symbols is referred to as symbol C, symbol D, and symbol E, the two REGs in symbol D can be consecutive in the frequency domain, and the two REGs in symbol E can also be consecutive in the frequency domain. Furthermore, the two REGs in symbol C, the two REGs in symbol D, and the two REGs in symbol E can lie in the same frequency domain.

[0312] When using a non-interleaved mapping method and the length of the CORESET corresponds to one symbol, i) REG bundles can be generated by bundling six consecutive REGs in the frequency domain. ii) REG bundles can be generated by bundling two consecutive REGs in the frequency domain. When using an interleaved mapping method and the length of the CORESET corresponds to two symbols, REG bundles can be generated by bundling one REG for each symbol. In this case, one REG for each symbol can be located in the same frequency domain. When using an interleaved mapping method and the length of the CORESET corresponds to three symbols, REG bundles can be generated by bundling one REG for each symbol. In this case, one REG for each symbol can be located in the same frequency domain.

[0313] A CCE can be generated by bundling REG bundles produced using the method described above. Here, a CCE can include 6 REGs. That is, since the generated REG bundles include 2, 3, or 6 REGs, a CCE can include 3, 2, or 1 REG bundles. For non-interleaved mappings, REG bundles always include 6 REGs regardless of the length of the CORESET. Here, a CCE can include one REG bundle.

[0314] In the following sections of this specification, a new CORESET, different from the existing CORESET, is proposed. The new CORESET may include at least one of the REGs, REG bundles, and CCEs that are different from those of the existing CORESET. The method for configuring the new CORESET will be described below.

[0315] i) Method A

[0316] The new coreset can be configured to include at least six consecutive symbols. The base station can send information about the coreset to the UE and configure a coreset including six consecutive symbols. Here, the information about the coreset can include information about the starting symbol and the symbol length (number) used to configure the new coreset. The UE can determine the structure of REG, REG bundles, and CCE based on the coreset including six symbols configured from the base station. For ease of explanation, the six consecutive symbols are represented as symbol #0, symbol #1, symbol #2, symbol #3, symbol #4, and symbol #5.

[0317] Figure 29 The diagram illustrates the configuration of a control resource set according to an embodiment of the present disclosure.

[0318] refer to Figure 29 REG, REG bundles, and CCE can be configured as follows.

[0319] i) A REG may include 12 REs contained in one PRB for each of the 6 symbols. ii) A REG bundle may include 6 REGs for the 6 symbols. That is, a REG bundle may include the REG corresponding to symbol #0, the REG corresponding to symbol #1, ..., and the REG corresponding to symbol #5. Since one REG includes 12 REs, a REG bundle including 6 REGs may include 72 REs. iii) A CCE may include one REG bundle. (See reference) Figure 29 The number of REGs constituting a REG bundle is the same as the number of symbols constituting a CORESET. However, when... Figure 29When the CCE is configured as shown, the UE cannot obtain frequency diversity because each REG bundle constituting the CCE is located in the same PRB. Therefore, when the UE detects a CCE, a problem of PDCCH reception performance degradation may occur.

[0320] Figure 30 The diagram illustrates the configuration of a control resource set according to an embodiment of the present disclosure.

[0321] refer to Figure 30 REG, REG bundles, and CCE can be configured as follows.

[0322] i) A REG may include the 12 REs included in one PRB for each symbol. ii) A REG bundle may include S REGs corresponding to S consecutive symbols. The method for determining the S consecutive symbols will be described later. A REG bundle may include the REs included in the S symbols of one PRB (i.e., 12 REs). S REs). Here, the value of "S" can correspond to one of 1, 2, or 3, and can be a value configured at a higher level. The six consecutive symbols constituting the CORESET can be divided into 6 / S symbol sets. In this case, each symbol set can include S consecutive symbols. For example, the first symbol set of the 6 / S symbol sets can include symbol #0, symbol #1, ..., and symbol #(S-1), while the second symbol set can include symbol #S, symbol #(S+1), ..., and symbol #(2S-1). S-1). Subsequent symbol sets may include S consecutive symbols. iii) CCE may include 6 / S REG bundles. Here, CCE may include one REG bundle selected from each symbol set. The index of the REG bundle can be configured for each symbol set. Alternatively, the UE can configure CCE by selecting REG bundles with the same index in each symbol set. In each symbol set, the index of the REG bundle can be interleaved. Simultaneously, an index can be configured for all REG bundles constituting the CORESET. CCE may include 6 / S consecutive REG bundles in the configured indexed REG bundle. That is, CCE x may include REG bundle #(6 / S) x), REG bundled#(6 / S) x+1) and REG bundled #(6 / S (x+6 / S-1). The method for configuring the index of REG bundles is as follows. Indexing can begin with the REG bundle corresponding to the earliest time-dependent symbol among the six symbols constituting the CORESET. Within the PRBs constituting the CORESET, REG bundles constituting the PRB located in the lowest frequency domain can be indexed based on the time domain, and then REG bundles included in the PRB located in the next lowest frequency domain can be indexed in the time domain. Here, the indexes being indexed can be interleaved.

[0323] ii Method B

[0324] A new core set can include multiple base core sets. A base core set can include 1 to 3 consecutive symbols. That is, the base station can send information about the new core set to the UE, and here, the information about the new core set includes information about the number of base core sets that constitute the new core set and information about the number of symbols (1 to 3 consecutive symbols) that constitute the base core set.

[0325] Figure 31 The diagram illustrates a control resource set including a basic control resource set according to an embodiment of the present disclosure.

[0326] refer to Figure 31 Each of the four basic cores (cores #0, #1, #2, and #3) can include two symbols. A new core can include all four basic cores. Figure 31 In the diagram, four basic cores are shown as being configured with the same length (number of symbols) and frequency band, but basic cores can be configured with different lengths and frequency bands. Furthermore, although each basic core is located contiguously on a time-domain resource, this is not a limitation and they can be non-contiguous.

[0327] The following describes a method for determining a plurality of basic CORESETs and the arrangement of symbols constituting the plurality of basic CORESETs.

[0328] The symbols constituting multiple basic cores can be consecutive in the time domain. Simultaneously, the UE can receive the start symbol indexes of multiple basic cores from the base station. For example, the UE can receive a bitmap with a size (length) of 14 bits. Here, the MSB of the bitmap can indicate the first symbol of the time slot as the start symbol index, while the LSB of the bitmap can indicate the last symbol of the time slot as the start symbol index.

[0329] Figure 32The diagram illustrates a control resource set including a basic control resource set according to an embodiment of the present disclosure.

[0330] refer to Figure 32 A 14-bit bitmap can be [10010000101000]. Here, the index of the symbol corresponding to 1 in the bitmap can be 0, 3, 8, or 10. Therefore, the basic control resource set can be configured to start at symbols 0, 3, 8, and 10.

[0331] The UE can receive 14 from the base station A bitmap of size N bits. The bitmap can indicate the start symbol index of N time slots. Specifically, the bitmap can be divided into bundles of 14 bits, where each 14-bit bundle's MSB indicates the first symbol of the time slot as the start symbol index, and the LSB indicates the last symbol of the time slot as the start symbol index.

[0332] Figure 33 The diagram illustrates a method for designing a control resource set using a basic control resource set according to an embodiment of the present disclosure.

[0333] refer to Figure 33 The base station can send a 28-bit bitmap to the UE. Here, the first 14 bits indicate the position of the starting symbol of the basic CORESET in the first time slot, and the next 14 bits indicate the position of the starting symbol of the basic CORESET in the second time slot. Since the first 14 bits are [10010000000000], the basic CORESET can be configured starting from symbols 0 and 3 of the first time slot. Since the next 14 bits are [10100000000000], the basic CORESET can be configured starting from symbols 0 and 2 of the second time slot.

[0334] Each of the multiple basic cores can be configured with a different symbol length (number). The base station can send the position and length of the start symbol of the configured basic core in a time slot to the UE. Here, the position and length of the start symbol can be configured in pairs. In addition, the frequency domains of the multiple basic cores can all be the same.

[0335] Figure 34 The diagram illustrates a method for configuring a control resource set using a basic control resource set according to an embodiment of the present disclosure.

[0336] Furthermore, the frequency domains of multiple basic cores can be different from each other. (Reference) Figure 34A new coreset can include four basic coresets. Here, multiple basic coresets can be configured with resources in different frequency domains. For example, the first basic coreset (coreset #0) can include all remaining PRBs in the frequency domain except for the lowest 6 PRBs. The second basic coreset (coreset #1) can include all remaining PRBs in the frequency domain except for the highest 6 PRBs. The third basic coreset (coreset #2) and the fourth basic coreset (coreset #3) can include all remaining PRBs except for the middle 6 PRBs. As described above, this method is advantageous in terms of frequency diversity because the basic coresets are configured with resources in different frequency domains.

[0337] The following text describes how to configure each base CORESET when it is configured with resources in different frequency domains.

[0338] The base station can configure the frequency resources of the basic core set using different bitmaps. For example, there exists a bitmap corresponding to each of the multiple basic core sets, and each bitmap can indicate whether six bundled PRBs constitute a basic core set. Here, the number of PRBs constituting each basic core set can be the same.

[0339] A base station can configure frequency domain resources using two different bitmaps. The first bitmap indicates the frequency domain resources for odd-numbered base cores, and the second bitmap indicates the frequency domain resources for even-numbered base cores. To summarize this method, the base station can indicate the frequency domain resources of a base core to the UE using B different bitmaps. In this case, if n mod B is 0, the first bitmap indicates the frequency domain resources of base core n, and if n mod B is 1, the second bitmap indicates the frequency domain resources of base core n. In other words, if n mod B is k, the (k+1)th bit of the bitmap indicates the frequency domain resources of the base core. In this case, n can be indexed from 0 to the index of the base core.

[0340] The base station can send PRB offset values ​​between base cores to the UE. For example, a bitmap can be used to indicate the frequency domain resources of the odd-numbered base cores among multiple base cores. Here, the bitmap can indicate whether the bundled 6 PRBs are included in the odd-numbered base cores. Additionally, the base station can send PRB offsets to the UE. The PRB offset can be in units of 6 PRBs. The PRBs included in the even-numbered base cores can be the PRBs corresponding to the index value obtained by adding the PRB offset to the index of the PRBs included in the odd-numbered base cores.

[0341] When a base station configures a new CORESET for a UE, the UE can receive PDCCH from each basic CORESET. The method for receiving PDCCH by the UE is described below.

[0342] The CCEs of the base CORESET can be indexed in a frequency-first manner. That is, among the base CORESETs that constitute a new CORESET, the CCEs included in the earliest base CORESET in the time domain can be selected first, and the selected CCEs can be indexed in ascending order in the frequency resource domain. In this case, if the number of the first CCEs included in the earliest base CORESET in the time domain is N_CCE0, then the first CCEs can be indexed in ascending order in the frequency domain as 0, 1, ..., N_CCE0-1. The second CCEs included in the base CORESET preceding the second CCE in the time domain can be indexed in ascending order in the frequency domain. The index of the second CCE can be used in the time domain with the value after the last index of the first CCE. If the number of CCEs included in the second CCE is N_CCE1, then the second CCEs can be indexed in ascending order in the frequency domain as N_CCE0, N_CCE0+1, ..., N_CCE0+N_CCE1-1. In the same method, the CCE of the base CORESET that constitutes the new CORESET can be indexed.

[0343] Simultaneously, the CCEs of the base CORESET constituting the new CORESET can be indexed in a time-priority manner. For example, in the base CORESET constituting the new CORESET, the CCEs constituting the lowest frequency domain PRB can be selected first, and the selected CCEs can be indexed in ascending order in the time domain. Here, if the number of the first CCEs constituting the lowest frequency domain PRB is N_CCE0, then the first CCEs can be indexed in ascending order in the time domain as 0, 1, ..., N_CCE0-1. The second CCEs constituting the second lowest frequency domain PRB can be indexed in ascending order in the time domain. The index of the second CCE can be used in the frequency domain with the value after the last index of the first CCE. If the number of the second CCEs is N_CCE1, then the second CCEs can be indexed in ascending order in the time domain as N_CCE0, N_CCE0+1, ..., N_CCE0+N_CCE1-1. The CCEs of the base CORESET constituting the new CORESET can be indexed in the same way.

[0344] Figure 35 The illustration shows a method for indexing CCEs in a frequency-first manner according to an embodiment of the present disclosure.

[0345] refer to Figure 35 Each base core set constituting the new core set can include 8 core components (CCEs). In this case, the CCEs corresponding to the first base core set (base core set #0) located in symbols 0 and 1 can be indexed in frequency priority as 0, 1, 2, 3, 4, 5, 6, and 7. The CCEs corresponding to the second base core set (base core set #1) located in symbols 2 and 3 can be indexed in frequency priority as 8, 9, 10, 11, 12, 13, 14, and 15. The CCEs of the remaining base core sets constituting the new core set can be indexed in the same manner.

[0346] Figure 36 The illustration shows a method for indexing CCEs in a time-first manner according to an embodiment of the present disclosure.

[0347] refer to Figure 36 Each PRB included in the new CORESET can include four CCEs. In this case, the CCEs in the lowest frequency domain can be indexed as 0, 1, 2, and 3 in a time-first manner. The CCEs in the second lowest frequency domain can be indexed as 4, 5, 6, and 7 in a time-first manner. The CCEs of the remaining base CORESETs that constitute the new CORESET can be indexed in the same manner.

[0348] The UE can receive PDCCHs with an aggregation level of L from L CCEs that constitute the basic CORESET. In this case, i) L can be a power of 2. For example, L can be 1, 2, 4, 8, 16, 32, etc. Alternatively, ii) L can be 2^k. The value of C. “k” is a natural number, and “C” is the number of the base cores, which can be a natural number. For example, if the new core includes three base cores, then L can have a value such as 1. 3, 2 3, 4 3, 8 3, 16 3, 32 The value of 3, etc.

[0349] Figure 37 The illustration shows PDCCH candidates based on CCEs indexed in a frequency-first manner, according to an embodiment of this disclosure. Figure 38 The illustration shows PDCCH candidates based on time-priority indexed CCEs according to an embodiment of the present disclosure.

[0350] refer to Figure 37 The CCEs constituting a new CORESET can be indexed in a frequency-priority manner. Here, the area where the UE monitors PDCCH candidates can be CCE 12 to CCE 23 (12 CCEs). The UE can recognize that the CCEs used for monitoring PDCCH candidates based on CCE indexing correspond to the 4 CCEs included in the second basic CORESET (basic CORESET #1) and all CCEs included in the third basic CORESET (basic CORESET #2).

[0351] refer to Figure 38 The CCEs constituting a new CORESET can be indexed in a time-priority manner. Here, the area where the UE monitors PDCCH candidates can be CCE 12 to CCE 23 (12 CCEs). The UE can recognize that the CCEs used for monitoring PDCCH candidates based on CCE indexing correspond to 3 CCEs in each of the 4 basic CORESETs.

[0352] The CCEs of the base CORESET constituting the new CORESET can be independently indexed. For example, if the number of CCEs constituting the first base CORESET in the base CORESET constituting the new CORESET is N_CCE0, then the CCEs constituting the first base CORESET can be indexed as one of the values ​​0, 1, ..., N_CCE0-1. Similarly, if the number of CCEs constituting the second base CORESET in the base CORESET constituting the new CORESET is N_CCE0, then the CCEs constituting the second base CORESET can be indexed as one of the values ​​0, 1, ..., N_CCE0-1. Here, the UE can determine the CCEs for receiving PDCCH on the first base CORESET. The UE can receive PDCCH with aggregation level L from L CCEs constituting the first base CORESET. The UE can receive PDCCH with aggregation level L from L CCEs constituting the second CORESET. Here, the PDCCH received on the first CORESET and the PDCCH received on the second CORESET can include the same DCI. That is, the UE can repeatedly receive PDCCH on different base CORESETs that constitute a new CORESET. Here, L can be a value that is a power of 2. For example, L can have values ​​of 1, 2, 4, 8, 16, 32, etc.

[0353] Figure 39 The illustration shows repeated reception of PDCCH on the basic control resource set according to an embodiment of the present disclosure.

[0354] refer to Figure 39The UE can independently index the CCEs of the base CORESET that constitute a new CORESET. The UE can receive a first PDCCH with aggregation level 4 on the first base CORESET (base CORESET #0). Here, the area monitored by the UE for receiving PDCCHs with aggregation level 4 can correspond to CCE2, CCE3, CCE4, and CCE5 included in the first base CORESET (base CORESET #0). The UE can receive a second PDCCH with aggregation level 4 on the second base CORESET (base CORESET #1). Here, the area monitored by the UE for receiving PDCCHs with aggregation level 4 can correspond to CCE2, CCE3, CCE4, and CCE5 included in the second base CORESET (base CORESET #1). Similarly, the UE can receive a third PDCCH and a fourth PDCCH on the third base CORESET (base CORESET #2) and the fourth base CORESET (base CORESET #3), respectively. In this scenario, each DCI included in the first, second, third, and fourth PDCCHs can be identical to each other. That is, the UE can monitor and receive PDCCHs containing the same DCIs through 16 CCEs.

[0355] When REGs are bundled to form CCEs, interleaving can be applied differently to each basic core set. This is to distribute the CCEs included in each basic core set to different frequency bands. Therefore, multiplexing between a basic core set and another basic core set that overlaps with it can be straightforward.

[0356] The following describes how to apply interleaving to each base CORESET. First, if the index of the REG bundle that makes up the base CORESET is x, then the index of the interleaved REG bundle can be f(x). f(x) is expressed as in Equation 1.

[0357] [Equation 1]

[0358] In equation 1, N REG CORESET L can be the number of REGs that make up the base CORESET, and L can be the number of REGs that make up the REG bundle. Therefore, N REG CORESET / L can correspond to the number of REG bundles in the base CORESET. R can be one of 2, 3, or 6. shiftThis can be a shift value applied when interleaving is performed on the indexes of the REG bundles that make up each base CORESET. Based on n shift REG-bound indexes can be interleaved differently. shift It can be a value configured by the base station to the UE or the cell ID.

[0359] The base station can be configured differently for each basic core set, applying n to each basic core set. shift Values ​​are used to interleave indices of different REG bundles from different base CORESETs. The UE can be based on n configured in each base CORESET. shift The values ​​are used to interweave the REG bound indexes.

[0360] The base station can configure a value (n) in the UE. shift,0 Here, the UE can be configured to apply n differently for each base CORESET. shift,0 Value. For example, the UE can use n shift,0 The multiple of the value is determined as n shift The value is used to interleave the index of REG bundles. Additionally, the UE can add the value based on the number of REG bundles to n. shift,0 The value determines n shift Value. For example, n can be... shift The value is determined to be n shift,0 + N REG CORESET / L / N n. Here, N is the number of base cores that constitute a new core, and n is the index of the base core and can have values ​​of 0, 1, ..., N-1. If n shift,0 +N REG CORESET / L / N If the value of n is not an integer, the UE can determine n as an integer value obtained by applying one of the ceil, floor, and round operations. shift,0 +N REG CORESET / L / N The value of n. This is the CCE index, which is configured equally according to the number of REG bundles, differing by n. shift The method of value.

[0361] Figure 40 The illustration shows repeated reception of PDCCH candidates by a terminal through interleaving of a basic control resource set according to an embodiment of the present disclosure.

[0362] Figure 40The illustration shows an example of a method for determining the index of the CCE constituting each base core set by using different interleaving for each base core set when the CCEs of the base core set constituting the new core set are independently indexed as described above. Reference Figure 40 n shift,0 +N REG CORESET / L / N 0 can be used as n for the first base CORESET (base CORESET #0) shift Value, n shift,0 +N REG CORESET / L / N 1 can be used as n for the second base CORESET (base CORESET #1) shift Value, n shift,0 +N REG CORESET / L / N 2 can be used as n for the third base CORESET (base CORESET #2). shift Value, and n shift,0 +N REG CORESET / L / N 3 can be used as n for the fourth base CORESET (base CORESET #3). shift Value. In this case, L can be 6, N can be 4, N REG CORESET It can be 48, R can be 2, and n shift,0 It can be 0. Because different n shift The values ​​are applied to different base cores, so interleaving can be performed differently for each base core. Furthermore, the CCE0 of each base core can be located in the lowest frequency domain in the first base core (base core #0), in the frequency domain corresponding to 1 / 4 of the entire band in the second base core (base core #1), in the frequency domain corresponding to 2 / 4 of the entire band in the third base core (base core #2), and in the frequency domain corresponding to 3 / 4 of the entire band in the fourth base core. Therefore, the CCE0 of each base core can be evenly distributed across the frequency band.

[0363] refer to Figure 40The UE can receive PDCCHs with aggregation level 4 on the first base core set (base core set #0). Here, the area monitored by the UE to receive PDCCHs with aggregation level 4 can correspond to CCE2, CCE3, CCE4, and CCE5 of the first base core set. Similarly, the UE can receive PDCCHs with aggregation level 4 by monitoring CCE2, CCE3, CCE4, and CCE5 of each of the second, third, and fourth base core sets. In this case, the PDCCHs with aggregation level 4 received on each of the first, second, third, and fourth base core sets can include the same DCI. Since different interleaving is applied to each base core set, CCE2, CCE3, CCE4, and CCE5 of each base core set can be distributed and set in the frequency domain. Therefore, this method is effective in terms of frequency diversity.

[0364] The method for receiving PDCCH by the UE will be described below. Here, PDCCH can be sent on a CORESET, and the CORESET can correspond to an existing CORESET or the new CORESET described above.

[0365] iii) Method C

[0366] The base station can send information to the UE about a CORESET and information about multiple search spaces corresponding to a CORESET. Each of the multiple search spaces can have a period and an offset. Here, the period and offset can be configured on a time slot basis. The information about the multiple search spaces can include information about the index of the start symbol for which the UE performs monitoring in order to receive PDCCH in a time slot. The UE can monitor and receive PDCCH in the area determined based on the period and offset of each of the multiple search spaces received from the base station and the index of the start symbol. That is, the UE can receive PDCCH in each of the multiple search spaces corresponding to a CORESET. In this case, the DCI included in the PDCCH received in each of the multiple search spaces can be the same as each other. Therefore, PDCCH can be transmitted repeatedly.

[0367] The base station can configure an index in each of multiple search spaces to send PDCCHs containing the same DCI to the UE across multiple search spaces. That is, the UE can identify the indexed search spaces configured by the base station to send the same DCI. For example, the UE receives search spaces 1 and 2 configured by the base station, and the UE can identify that the DCIs included in the PDCCHs repeatedly sent in search spaces 1 and 2 are the same. Here, the period of search space 1 and the period of search space 2 can be the same. In other words, the base station can configure the same period for multiple search spaces to send the same DCI, so the UE can determine the interval (resource domain) in which the PDCCHs are repeatedly sent. For example, if the period of search space 1 and the period of search space 2 are equal to P, then the UE can index its time slot as P. n, P n+1, ..., P The time slot n+P-1 is determined as the interval in which PDCCH is repeatedly transmitted, and PDCCHs including the same DCI can be repeatedly transmitted in multiple search spaces included in the determined interval. In this case, n can have values ​​of 0, 1, 2, ..., etc.

[0368] Figure 41 The illustration shows repeated transmission of PDCCH in multiple search spaces according to embodiments of the present disclosure.

[0369] refer to Figure 41 Two search spaces can be configured within a single CORESET. The period of the first search space (search space #A) can be 4 time slots, and the offset can be 0 time slots. Therefore, the UE can perform monitoring to receive PDCCHs in the first search space (search space #A) for time slots 0, 4, and 8. The period of the second search space (search space #B) can be 4 time slots, and the offset can be 1 time slot. Therefore, the UE can perform monitoring to receive PDCCHs in the second search space (search space #B) for time slots 1, 5, and 9. When the UE is configured to repeatedly receive PDCCHs containing the same DCI in multiple search spaces, the UE can receive repeated PDCCHs containing the same DCI in the search spaces of time slots 0, 1, 2, and 3 based on a common period (the period of the first and second search spaces). Additionally, the UE can receive repeated PDCCHs transmitting the same DCI in the search spaces of time slots 4, 5, 6, and 7 based on a common period.

[0370] Meanwhile, the periods of the first search space and the second search space can be different from each other. In this case, it is necessary to define the resource domain (interval) in which PDCCH is repeatedly transmitted. The period in which PDCCH is repeatedly transmitted can be determined based on the least common multiple of the periods of the first and second search spaces. The period in which PDCCH is repeatedly transmitted can be determined based on the greatest common divisor of the periods of the first and second search spaces. The period in which PDCCH is repeatedly transmitted can be determined based on the larger period between the periods of the first and second search spaces. The period in which PDCCH is repeatedly transmitted can be determined based on the smaller period between the periods of the first and second search spaces. The base station can send (configured in the UE) the period of the interval in which PDCCH is repeatedly transmitted to the UE.

[0371] The base station can send (configured in the UE) multiple periods and offset values ​​for a search space to the UE. Additionally, the base station can send (configure) the UE to perform monitoring to receive the start symbol of the PDCCH in multiple time slots. The UE can receive repeated PDCCHs including the same DCI based on the multiple periods, offset values, and start symbol indices.

[0372] To transmit PDCCHs containing the same DCI within the search space, the base station can send (configured in the UE) a search space period and offset value. Additionally, the base station can send (configured in the UE) the index of the starting symbol to be monitored for receiving PDCCHs within a time slot. Furthermore, the base station can indicate the number (K) of time slots configured with the search space repeatedly monitored by the UE. The number of time slots (K) can be a natural number less than the period of the search space. Specifically, the search space in which the UE performs monitoring to receive PDCCHs can be configured based on the period. The search space can be configured based on the index of the starting symbol in the time slot indicated by the base station. In other words, the search space can be configured starting from the starting symbol indicated by the index. Additionally, the base station can indicate the number (K) of time slots used to configure the search space repeatedly monitored by the UE. For example, if the base station indicates a value of 2 for K, the search space can be configured equally in time slot n and time slot (n+1). Here, the index of the symbol in which the search space begins and the time slot index are equal to "n". Therefore, the search space for time slot n and time slot (n+1) can be configured starting from the symbol n of each time slot.

[0373] Figure 42 The illustration shows the transmission of PDCCH based on search space and repeated configuration according to an embodiment of the present disclosure.

[0374] refer to Figure 42The search space period can be configured with 4 time slots, and the offset can be configured with 0 time slots. Therefore, the search space can be configured in time slots 0, 4, 8, ..., etc. Additionally, the UE can receive an indication of the number of time slots (K) for repeatedly monitoring the search space, where K is 2. Here, the UE can be configured to monitor the search space for repeated PDCCHs in the subsequent time slots (time slot 1, time slot 5, time slot 9, ...) following the time slots configured with the first search space (time slot 0, time slot 4, time slot 8, ...).

[0375] The base station can send (configured in the UE) a search space period and offset value. Additionally, the base station can send (configured) K indices of the starting symbol for the UE to perform PDCCH monitoring in a time slot. Specifically, the UE can perform monitoring based on the first index of the symbol for which monitoring begins to receive PDCCH in time slot n. For example, if the first index is 0, the search space is configured starting from the first symbol of time slot n, and the UE can perform monitoring in the search space of time slot n for PDCCH reception. The UE can also perform monitoring based on the second index of the symbol for which monitoring begins to receive PDCCH in time slot (n+1). For example, if the second index is 2, the search space is configured starting from the third symbol of time slot (n+1), and the UE can perform monitoring in the search space of time slot (n+1) for PDCCH reception.

[0376] Figure 43 The illustration shows the transmission of PDCCH based on search space and repetitive configuration according to different start symbol positions, according to an embodiment of the present disclosure.

[0377] refer to Figure 43 The search space can be configured with a period of 4 time slots and an offset of 0 time slots. Therefore, the search space can be configured in time slots 0, 4, 8, ..., etc. Additionally, the base station can configure 0 and 7 as the starting symbol indexes for the search space. Therefore, the search space can be configured starting from symbol 0 in time slots 0, 4, 8, ..., and the repeated search space can be configured starting from symbol 7 in time slots 1, 5, 9, ..., corresponding to its next time slot.

[0378] A base station can configure multiple search spaces within a CORESET configured in a single time slot. For this purpose, the base station can indicate the starting symbol number (K) of the search space to the UE. For example, if the value of K is 2, then the number of search spaces configured in time slot n can be two. Specifically, a first search space can be configured starting from the first symbol of time slot n, and a second search space can be configured starting from the symbol immediately following the last symbol of the first search space.

[0379] A base station can configure multiple search spaces within a CORESET configured in a single time slot. For this purpose, the base station can indicate K indices of the starting symbol of the search space to the UE. For example, if the value of K is 2, the starting symbol indices indicated by the base station can be a first index and a second index, and two search spaces can exist. In this case, if the value of the first index is 0, the first search space can be configured starting from the first symbol of time slot n, while if the value of the second index is 2, the second search space can be configured starting from the third symbol of time slot n.

[0380] In method C described above, since the area in which the PDCCH is transmitted corresponds to a CORESET, the resources in the frequency domain are fixed in some frequency bands, and the number of symbols in the CORESET is fixed. A CORESET in this specification can refer to the same time-frequency domain resources configured for each time slot. Therefore, method C may be disadvantageous in terms of frequency diversity and may not adjust the number of symbols according to the time slot configuration. Methods to address these problems will be described below.

[0381] iv) Method D

[0382] A base station can be configured with multiple cores within a single DL BWP. Resources in the time-frequency domain of each core can be configured independently. Furthermore, one or more search spaces can be configured on each core. Specifically, multiple search spaces can be mapped to corresponding cores based on indicators that specify the cores.

[0383] For example, different search spaces can be configured in each of the multiple cores. The base station can send an indicator to the UE indicating that the PDCCH is repeatedly transmitted on the multiple cores. Specifically, the base station can send an indicator to the UE indicating that the PDCCH is repeatedly transmitted on the first core and the second core. In this case, if the value of the indicator is "1", the repeated PDCCH is transmitted in the first search space corresponding to the first core, and if the value of the indicator is "2", the repeated PDCCH is transmitted in the second search space corresponding to the second core. In this case, the DCIs included in the PDCCHs repeatedly transmitted on the multiple cores can be the same as each other.

[0384] For example, a base station can configure a search space with multiple cores. Specifically, the UE can receive from the base station an indicator that a search space is mapped to which core among the multiple cores. Additionally, the UE can receive (configure) the period, offset, and start symbol index of the search space from the base station. The search space determined based on the period, offset, and start symbol index can be sequentially mapped to multiple cores. In this case, the DCI included in the PDCCH transmitted on multiple cores can be the same. Since DCI can be transmitted on multiple cores, frequency diversity can be achieved.

[0385] Figure 44 The illustration shows the transmission of PDCCH on multiple control resource sets according to embodiments of the present disclosure.

[0386] refer to Figure 44 The search space period can be 2 time slots, and the offset can be 0 time slots. Therefore, search spaces can be configured in time slots 0, 2, 4, 6, 8, ... . Each search space configured in time slots 0, 2, 4, 6, 8, ... can be mapped to one of two CORESETs (CORESET#A, CORESET#B). Odd-numbered search spaces (i.e., those configured in time slots 0, 4, and 8) can be mapped to CORESET#A, while even-numbered search spaces (i.e., those configured in time slots 2 and 6) can be mapped to CORESET#B. Here, the interval for transmitting PDCCH resources can be equal to the value obtained by multiplying the search space period by the number of CORESETs. That is, 4, obtained by multiplying 2 (the search space period) by 2 (the number of CORESETs), can be the interval for transmitting PDCCH resources, and the unit of this interval can be a time slot. The UE can receive PDCCH during the intervals of time slots 0, 1, 2, and 3. Additionally, the UE can receive PDCCH during the intervals of time slots 4, 5, 6, and 7.

[0387] The search space can be configured based on multiple indices of periods, offsets, and start symbols configured by the base station. Since multiple search spaces correspond to multiple CORESETs, the number of search spaces and the number of CORESETs can be the same. In other words, the number of sets of configuration values ​​for each search space can be the same as the number of CORESETs. Here, this set can include multiple indices of periods, offsets, and start symbols. For example, a search space determined based on the indices of a first period, offset, and start symbol can be mapped to a first CORESET, while a search space determined based on the indices of a second period, offset, and start symbol can be mapped to a second CORESET.

[0388] Alternatively, the search space can be configured based on the number of time slots (K) in which the search space is repeated. In this case, K can be the same as the number of CORESETs, so K can be configured without separate signaling. For example, if K has a value of 2, time slot n is determined based on the period and offset, the search space determined based on the start symbol index in time slot n can be mapped to the first CORESET, and the search space determined based on the start symbol index in time slot (n+1) can be mapped to the second CORESET.

[0389] Alternatively, the search space can be determined based on the number of indices of the start symbols. Here, the number of indices of the start symbols and the number of CORESETs can be the same. For example, if the index of the start symbol is two, the search space determined based on the index of the first start symbol in slot n can be mapped to the first CORESET, while the search space determined based on the index of the second start symbol in slot (n+1) can be mapped to the second CORESET.

[0390] v) Method E

[0391] A method for receiving DM-RS that includes repeated PDCCHs of the same DCI sent from the base station to the UE will be described.

[0392] A wideband reference signal (RS) can be configured. The UE can determine the REG assuming the same precoder based on whether a wideband RS is configured.

[0393] If a wideband RS is not configured, the UE can assume that the same precoder is applied to the REGs that constitute the REG bundle. That is, the UE can use the DM-RS of the REGs included in the REG bundle to perform channel estimation. The UE can then compensate for the phase of signals received from REs included in the REG bundle based on the channel estimation results.

[0394] When wideband RS is configured, the UE can assume that the same precoder is applied to adjacent REGs in the time-frequency domain. The UE can assume that the same precoder is applied to adjacent REGs in the time-frequency domain among REGs mapped to multiple CORESETs. In this case, each of the multiple CORESETs can correspond to an area in which the same DCI is transmitted. Additionally, the UE can assume that the same precoder is applied to adjacent REGs in the time-frequency domain among REGs corresponding to multiple search spaces. In this case, PDCCHs including the same DCI can be transmitted in the search space. The UE can assume that the same precoder is applied to adjacent REGs in the time-frequency domain among REGs included in a CORESET. In other words, even if REGs of different CORESETs are adjacent to each other in the time-frequency domain, the UE does not assume the application of the same precoder. Different CORESETs can include CORESETs in which the same DCI is repeatedly transmitted. On the other hand, CORESETs in which the same DCI is repeatedly transmitted can be excluded from different CORESETs. The UE can assume that the same precoder is applied to adjacent REGs in the time-frequency domain among REGs corresponding to a search space. In other words, even if adjacent REGs in the time-frequency domain are included in the same CORESET, the UE does not assume the application of the same precoder when adjacent REGs correspond to different search spaces. Different search spaces can include search spaces in which the same DCI is transmitted. On the other hand, search spaces in which the same DCI is transmitted can be excluded from different search spaces.

[0395] The UE can assume that the same precoder has been applied to REGs (multiple base CORESETs constituting a CORESET, multiple search spaces corresponding to a CORESET, or multiple CORESETs) in which PDCCHs are repeatedly transmitted. The regions in which PDCCHs are repeatedly transmitted do not necessarily need to be adjacent in the time-frequency domain. That is, the UE can assume that the same precoder has been applied to REGs in non-adjacent regions included in the time-frequency domain. Therefore, the UE can assume that the same precoder has been applied to non-adjacent regions in the time-frequency domain, thus improving the performance of channel estimation using DM-RS.

[0396] REs on some symbols of the resources used by the base station to transmit duplicate PDCCHs containing the same DCI to the UE can be used to transmit the DCI instead of the DM-RS. For example, if duplicate PDCCHs containing the same DCI are configured to be transmitted on adjacent symbols, the base station can be configured not to allocate DM-RS to REs on all symbols for the transmission of duplicate PDCCHs. In this case, all or some symbols not allocated DM-RS can be used to transmit the DCI. Each duplicate PDCCH can be an adjacent PDCCH on a resource domain. The detailed method for allocating DM-RS will be described below.

[0397] i) The base station may not include DM-RS in some or all REs corresponding to the symbols of the PDCCHs that correspond to multiples of k in each round from which repeated PDCCHs are transmitted. For example, when k has a value of 2, the base station may be configured not to assign DM-RS to some or all symbols of the PDCCHs that correspond to multiples of 2 (i.e., even symbols) in each round from which repeated PDCCHs are transmitted. ii) The base station may be configured not to assign DM-RS to some or all REs corresponding to the symbols of the PDCCHs that are repeatedly assigned and transmitted to multiples of k in each round of repeated PDCCHs. For example, when k has a value of 2, the base station may be configured not to assign DM-RS to some or all REs corresponding to the symbols of each round of repeated PDCCHs that correspond to multiples of 2 (i.e., even symbols). iii) The base station may assign DM-RS to the RE corresponding to the k-th symbol of each repeated PDCCH, and may be configured not to assign DM-RS to the REs corresponding to the remaining symbols other than the k-th symbol. For example, if k has a value of 1, DM-RS may be assigned to the RE corresponding to the first symbol of each repeated PDCCH, and may not be mapped to REs corresponding to symbols other than the first symbol. iv) The base station may be configured to assign DM-RS to the REs corresponding to the first through k-th symbols of each repeated PDCCH, but not to all or some of the REs corresponding to the remaining symbols other than the first through k-th symbols. For example, if k has a value of 2, the base station may be configured to assign DM-RS to the REs corresponding to the first and second symbols of each repeated PDCCH, but not to all or some of the REs other than those corresponding to the first and second symbols. In iii) and iv) above, the value of k may be determined based on the number of symbols of the PDCCH transmitted. For example, k may be determined as ceil(PDCCH_length / 2). PDCCH_length is the number of symbols of the PDCCH transmitted by it. In other words, if the number of symbols transmitted via the PDCCH is 1 or 2, then k has a value of 1, and if the number of symbols is 3, then k has a value of 2. Here, the value of k can be a value configured by the base station.

[0398] vi) Method F

[0399] The same sequence can be used to assign DM-RS to repeated PDCCHs that include the same DCI. That is, the UE can be configured to determine that the DCIs included in repeated PDCCHs are identical, assuming that the same sequence is used for the DM-RS assigned to the repeated PDCCHs. Additionally, the UE can perform phase compensation by using or comparing the DM-RS assigned to repeated PDCCHs. The DCIs included in repeated PDCCHs can be the same.

[0400] More specifically, the allocation to time slot n can be determined as in Equation 2. s,f μ The sequence of DM-RS with symbol l.

[0401] [Equation 2]

[0402] In Equation 2, the initial value of the pseudo-random sequence c(i) can be calculated as in Equation 3 below.

[0403] [Equation 3]

[0404] In equation 3, n s,f μ It can be the index of a time slot in a subframe, l can be the index of a symbol in a time slot, and N ID It can be one of the values ​​0, 1, ..., 65535 or the same value as the cell ID.

[0405] The following section describes a method for applying the same sequence to DM-RS assigned to repeating PDCCHs.

[0406] i) The DM-RS sequence used for assigning to the repeating PDCCH can have the same initial value. The initial value can be determined using the symbol index and the index of the slot in which the first PDCCH is transmitted within the repeating PDCCH. The determined initial value can be used for each symbol in each slot in which the repeating PDCCH is transmitted. For example, the first PDCCH in the repeating PDCCH can be transmitted in symbols i and (i+1) of slot n1, and the second PDCCH in the repeating PDCCH can be transmitted in symbols j and (j+1) of slot n2. Here, the initial value of the DM-RS sequence for the second PDCCH can use the initial value of the DM-RS sequence for the first PDCCH. That is, the initial value of the DM-RS sequence used for assigning to the first symbol of the second PDCCH can correspond to c. init (n1, i), while the initial value of the DM-RS sequence used to assign the second symbol of the second PDCCH can correspond to c. init(n1, i+1). ii) When a repeated PDCCH is transmitted in a time slot, the symbols of the resource fields in which the repeated PDCCH is transmitted can be configured to have the same index value of 1. For example, when a repeated PDCCH is transmitted four times in a time slot, specifically, the first repeated PDCCH can be transmitted via symbols 0 to 2, the second repeated PDCCH via symbols 3 to 5, the third repeated PDCCH via symbols 6 to 8, and the fourth repeated PDCCH via symbols 9 to 11. Here, the index value I of the first symbol (i.e., symbols 0, 3, 6, and 9) in the region used to transmit each repeated PDCCH can be configured to 0, and the index value I of the second symbol (i.e., symbols 1, 4, 7, and 11) can be configured to 1. As another example, the symbol of the first PDCCH in the repeated PDCCH can be configured to have an index value of 1. That is, the index value of the symbol of the remaining PDCCHs other than the first PDCCH in the repeated PDCCH can be 1. iii) If repeated PDCCHs are sent in different time slots, the time slot index value n in the initial value of DM-RS will be... s,f μ They can all have the same value. For example, n in the first time slot in which PDCCH is repeatedly sent can be... s,f μ Configured to 0, and the n of the second time slot can be... s,f μ Configured to 1. As another example, n s,f μ It can be the index of the time slot in which the first PDCCH in a series of repeated PDCCHs is sent. That is, n is the index of the remaining PDCCHs besides the first PDCCH. s,f μ It can be the same as the index of the time slot in which the first PDCCH is sent.

[0407] iv)n s,f μ This can also be applied to N time slots. For example, n can be... s,f μ Determined as c init (floor(n s,f μ / N) N, l). Floor(x) is a function that returns the largest integer among those equal to or less than x. N can be a value configured by the base station. N can be a value determined based on the number of slots in which repeated PDCCHs are transmitted. N can be equal to the number of slots in which repeated PDCCHs are transmitted. v)n s,f μThis can also be applied to N time slots based on a specific time slot (e.g., time slot n0). For example, n can be... s,f μ Determined as c init (floor((n s,f μ - n0) / N) N, l). N can be a value configured by the base station. N can be a value determined based on the number of slots in which repeated PDCCHs are transmitted. N can be equal to the number of slots in which repeated PDCCHs are transmitted. n0 can be the index of the slot in which the first PDCCH is transmitted. n0 can be configured by the base station.

[0408] The CCE corresponding to the PDCCH candidate in the first search space of the first CORSET and the PDCCH candidate in the second search space of the second CORSET, which transmits duplicate PDCCHs including the same DCI, can be determined based on a hash function. The number of blind decodes and the number of non-overlapping CCEs used to monitor and receive duplicate PDCCH candidates in the first search space can be different from the number of blind decodes and the number of non-overlapping CCEs used to monitor and receive duplicate PDCCH candidates in the second search space. That is, the maximum number of blind decodes and the maximum number of non-overlapping CCEs per time slot (or during a specific time interval) can be different between the first and second search spaces. Therefore, the UE may receive duplicate PDCCHs in the first search space (i.e., when the condition of the maximum number of blind decodes and the maximum number of non-overlapping CCEs is met), but may not receive duplicate PDCCHs in the second search space. Therefore, it is difficult to extend coverage by repeatedly receiving duplicate PDCCHs. In the following, a method for applying a hash function to extend coverage will be described.

[0409] vii) Method G

[0410] The same hash function can be applied to regions in which repeated PDCCHs containing the same DCI are sent repeatedly (multiple base CORESETs constituting a CORESET, multiple search spaces corresponding to a CORESET, or multiple CORESETs).

[0411] Specifically, the time slots n constituting the search space s included in CORESET p can be determined by a hash function such as Equation 4. s,f μ PDCCH candidates The CCE. Here, the aggregation level of the PDCCH candidate can be L.

[0412] [Equation 4]

[0413] If the search space s is a public search space, then It can have a value of 0. If the search space s is a UE-specific search space, then equal ,and equal And it is not zero. Additionally, when p mod 3 is 0... This corresponds to 39827, when p mod 3 equals 1. This can correspond to 39829, while when p mod 3 is 2. This can correspond to 39839. D can correspond to 65537. n RNTI It can have a C-RNTI value.

[0414] If up to 5 CORESETs in which repeated PDCCHs can be sent are configurable, then p can have values ​​from 0 to 4. If the search space s is a UE-specific search space, then equal ,and equal And it is not zero. Additionally, when p mod 5 is 0... This corresponds to 39827, when p mod 5 equals 1. This can correspond to 39829, when p mod 5 equals 2. This can correspond to 39839, when p mod 5 equals 3. This can correspond to 39841, while when p mod 5 is 4... It can correspond to 39847. D can correspond to 65537.

[0415] It can be the number of CCEs that make up the CORESET. It can be the number of repeated PDCCH candidates with an aggregation level of L, which are monitored by the UE. It can be the value indicated by the carrier indicator field.

[0416] If the search space s is a public search space, then It can have a value of 0 regardless of the time slot. Therefore, if If the values ​​are the same, the hash function outputs the same value. Therefore, the CORESET corresponding to the search space in which repeated PDCCHs are sent can include the same number of CCEs. On the other hand, if the CORESET is not configured with the same number of CCEs, the UE needs to compute the hash function under the assumption of a specific number of CCEs.

[0417] The methods for determining a specific number are described below. When the number of CCEs constituting multiple CORESETs differs, the specific number can be determined based on the CORESET that includes the minimum number of CCEs. Alternatively, the specific number can be determined based on the CORESET that includes the maximum number of CCEs. Alternatively, the specific number can be determined based on the CORESET that sent the first PDCCH in a repeated PDCCH. Alternatively, the specific number can be determined based on the CORESET with the lowest index among the multiple CORESETs. Alternatively, the specific number can be determined based on the CORESET with the highest index among the multiple CORESETs.

[0418] If the search space s is a UE-specific search space, it can be determined differently for each time slot. Therefore, in order to output the same value in the hash function, you can... Fixed to a specific value. The method used to determine this will be described below. The method i) can ignore the time slot index. How will it all be? To determine a specific value. For example, it can be... It is determined to be a specific value that is different from the value used when the search space s is a common search space (i.e., 0). It can be based on N CCE,p A specific, definite value. Specifically, it can be based on N. CCE,p Determined by half For example, it can be based on floor(N) CCE,p / 2), ceil(N) CCE,p / 2) and round(N CCE,p / 2) to determine Round(x) is a function that returns the value obtained by rounding x. When based on N... CCE,p Determined by half At that time, half of the resources constituting the CORESET can be used as a common search space, while the other half can be used as a UE-specific search space. ii) It has a specific value for a predetermined time unit and can be changed for each predetermined time unit. The predetermined time unit can be a time slot unit and can be configured by the base station. Furthermore, the predetermined time unit can be the same as the number of times the PDCCH is repeatedly transmitted. For example, It can have a specific value during N time slots (for a predetermined unit of time). Specifically, if by using n s,f μ If the remainder after dividing by N is not zero, then equal However, if n s,f μ If the remainder when divided by N is 0, then It can be As another example, during N time slots, It is determined to be a fixed, specific value, and can be updated via offset M. M can have values ​​from 0 to N-1. If n s,f μ If the remainder when divided by N is not M, then equal However, if n s,f μ If the remainder when divided by N is M, then It can be M can be a value configured by the base station. As another example, the offset M can be determined based on the index S of the slot in which the first PDCCH in the repeated PDCCHs is transmitted. Specifically, M can be determined as S mod N. During the time slots in which repeated PDCCHs are sent, the same value can be used. iii) When repeated PDCCHs are sent on different CORESETs, since there are several values ​​of p as the CORESET index, the values ​​of p can be determined differently. Therefore, the p value can be fixed to a specific value. For example, the p value can be fixed to 0. As another example, the p value can be determined based on the index of the CORESET in which the first PDCCH in the repeated PDCCHs are sent. As yet another example, the p value can be determined based on the lowest or highest index in the configuration index of the CORESET.

[0419] Figure 45 This is a flowchart illustrating the transmission of a repeated PDCCH according to an embodiment of the present disclosure.

[0420] refer to Figure 45 The description has been referenced above. Figures 1 to 44 The method described is for sending duplicate PDCCHs that include the same DCI.

[0421] The UE can receive configuration information about the first CORESET from the base station, and can also receive configuration information about the second CORESET from the base station (S4510, S4520).

[0422] The UE can receive the first PDCCH sent on the first CORESET from the base station, and can also receive the second PDCCH (S4530, S4540) sent on the second CORESET.

[0423] Here, the first PDCCH and the second PDCCH can be repeatedly transmitted from the base station.

[0424] The first DCI included in the first PDCCH and the second DCI included in the second PDCCH can be the same as each other.

[0425] The first PDCCH and the second PDCCH can be configured with the same aggregation level (AL).

[0426] The first CORESET and the second CORESET can be resources in different time-frequency domains, and the first CORESET and the second CORESET can be resources in the same time-frequency domain.

[0427] The first PDCCH and the second PDCCH can be repeatedly transmitted while being included in the same time slot, and the first PDCCH and the second PDCCH can be repeatedly transmitted in different time slots.

[0428] The first DCI and the second DCI can be decoded independently, and the first DCI and the second DCI can be combined and decoded. In this case, when the UE fails to decode the first DCI and the second DCI independently, the UE can combine and decode the first DCI and the second DCI.

[0429] The UE can receive configuration information about a first search space from the base station and can also receive configuration information about a second search space. The first search space can be associated with a first core set, and the second search space can be associated with a second core set. Here, the first search space and the second search space can be resources in different time domains. Furthermore, the first PDCCH can be received in the first search space, and the second PDCCH can be received in the second search space.

[0430] The configuration information for the first search space may include information about its period, while the configuration information for the second search space may include information about its period. Here, the periods of the first and second search spaces can be the same.

[0431] The UE can send HARQ-ACK information to the base station for one of the first PDCCH and the second PDCCH. Here, the HARQ-ACK information can be HARQ-ACK information for the PDCCH sent on the search space of the lower index of the first search space index and the second search space index.

[0432] The UE can receive a third PDCCH from the base station in the third search space. The UE can send HARQ-ACK information to the base station for any one of the first, second, and third PDCCHs. Here, the third PDCCH may include a third DCI different from the first and second DCIs. When the third search space overlaps with the first or second search space, the HARQ-ACK information may be HARQ-ACK information for the PDCCH sent through the search space with the lowest index among the indices of the overlapping search spaces.

[0433] The types of the first search space and the second search space can be the same. Here, the types of the first search space and the second search space can be either a common search space or a UE-specific search space.

[0434] Execution Reference Figure 45 The UE described in the method can be referenced. Figure 11 The UE described herein. Specifically, the UE may include a communication module for transmitting and receiving radio signals, and a processor configured to control the communication module. Here, the UE's processor may be configured to perform the method for receiving repeated PDCCHs described in this specification.

[0435] Additionally, the base station described in this specification for transmitting repeated PDCCHs may include a communication module for transmitting and receiving radio signals, and a processor configured to control the communication module. Here, the base station may be a reference... Figure 11 The base station is described. Here, the base station's processor can be configured to perform the method for sending repeated PDCCHs described in this specification.

[0436] Although the methods and systems of this disclosure have been described in conjunction with specific embodiments, some or all of their components or operations may be implemented using a computing system with a general-purpose hardware architecture.

[0437] The above description of this disclosure is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be readily modified without altering the technical spirit or essential characteristics of this disclosure. Therefore, it should be understood that the above embodiments are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0438] The scope of this disclosure is indicated by the claims, which will be described later rather than in detail, and all variations or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included within the scope of this invention.

Claims

1. A user equipment (UE) configured to operate in a wireless communication system, the UE comprising: transceiver; as well as A processor configured to control the transceiver. The processor is configured as follows: Receive first configuration information related to multiple control resource sets (CORESET). Receive second configuration information associated with multiple search spaces, each search space being associated with each of the multiple CORESETs. The first downlink control information (DCI), which is included in the first physical downlink control channel (PDCCH), is received in the first search space among the plurality of search spaces. The second DCI, which is included in the second PDCCH, is received in the second search space among the plurality of search spaces. The second configuration information includes link information used to link the first search space and the second search space. The first search space and the second search space are configured in the same time slot. Wherein, the first DCI and the second DCI are identical to each other. On the resource, transmit the Physical Uplink Control Channel (PUCCH) carrying Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) information, and The resource is determined based on the PDCCH in the search space that has a lower search space index in the first search space and the second search space, among the first PDCCH and the second PDCCH.

2. The UE according to claim 1, in, The first PDCCH and the second PDCCH have the same polymerization grade AL.

3. The UE according to claim 1, in, The first CORESET associated with the first search space and the second CORESET associated with the second search space are different time-frequency resources. The first CORESET and the second CORESET are included in the plurality of CORESETs.

4. The UE according to claim 1, in, The period of the first search space and the period of the second search space are the same.

5. The UE according to claim 1, in, The types of the first search space and the second search space are the same, and The types of the first search space and the second search space are either a public search space or a UE-specific search space.

6. A method performed by a user equipment (UE) configured to operate in a wireless communication system, comprising: Receive first configuration information related to multiple control resource sets (CORESET); Receive second configuration information related to multiple search spaces, each search space being associated with each of the multiple CORESETs; Receive first downlink control information (DCI) included in the first physical downlink control channel (PDCCH) in the first search space among the plurality of search spaces; The second DCI, which is included in the second PDCCH, is received in the second search space among the plurality of search spaces. The second configuration information includes link information used to link the first search space and the second search space. The first search space and the second search space are configured in the same time slot. Wherein, the first DCI and the second DCI are identical to each other; On the resource, transmit the Physical Uplink Control Channel (PUCCH) carrying Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) information, and The resource is determined based on the PDCCH in the search space that has a lower search space index in the first search space and the second search space, among the first PDCCH and the second PDCCH.

7. The method according to claim 6, in, The first PDCCH and the second PDCCH have the same polymerization grade AL.

8. The method according to claim 6, in, The first CORESET associated with the first search space and the second CORESET associated with the second search space are different time-frequency resources. The first CORESET and the second CORESET are included in the plurality of CORESETs.

9. The method according to claim 6, in, The period of the first search space and the period of the second search space are the same.

10. The method according to claim 6, in, The types of the first search space and the second search space are the same, and The types of the first search space and the second search space are either a public search space or a UE-specific search space.

11. A base station (BS) configured to operate in a wireless communication system, the BS comprising: transceiver; as well as A processor configured to control the transceiver. The processor is configured as follows: Send the first configuration information related to multiple control resource sets (CORESET). Send second configuration information associated with multiple search spaces, each search space being associated with each of the multiple CORESETs. The first downlink control information (DCI), which is included in the first physical downlink control channel (PDCCH), is transmitted in the first search space among the plurality of search spaces. The second DCI, which is included in the second PDCCH, is transmitted in the second search space among the plurality of search spaces. The second configuration information includes link information used to link the first search space and the second search space. The first search space and the second search space are configured in the same time slot. Wherein, the first DCI and the second DCI are identical to each other. On the resource side, receive the physical uplink control channel PUCCH carrying hybrid automatic repeat request-acknowledge (HARQ-ACK) information, and The resource is determined based on the PDCCH in the search space that has a lower search space index in the first search space and the second search space, among the first PDCCH and the second PDCCH.

12. The BS according to claim 11, in, The first PDCCH and the second PDCCH have the same polymerization grade AL.

13. The BS according to claim 11, in, The first CORESET associated with the first search space and the second CORESET associated with the second search space are different time-frequency resources. The first CORESET and the second CORESET are included in the plurality of CORESETs.

14. The BS according to claim 11, in, The period of the first search space and the period of the second search space are the same.

15. The BS according to claim 11, in, The types of the first search space and the second search space are the same, and The types of the first search space and the second search space are either a public search space or a UE-specific search space.

16. A method performed by a base station (BS) configured to operate in a wireless communication system, the method comprising: Send the first configuration information related to multiple control resource sets (CORESET); Send second configuration information associated with multiple search spaces, each search space being associated with each of the multiple CORESETs; Transmit the first downlink control information (DCI) included in the first physical downlink control channel (PDCCH) in the first search space among the plurality of search spaces; The second DCI, which is included in the second PDCCH, is transmitted in the second search space among the plurality of search spaces. The second configuration information includes link information used to link the first search space and the second search space. The first search space and the second search space are configured in the same time slot. Wherein, the first DCI and the second DCI are identical to each other; On the resource side, receive the physical uplink control channel PUCCH carrying hybrid automatic repeat request-acknowledge (HARQ-ACK) information, and The resource is determined based on the PDCCH in the search space that has a lower search space index in the first search space and the second search space, among the first PDCCH and the second PDCCH.

17. The method according to claim 16, in, The first PDCCH and the second PDCCH have the same polymerization grade AL.

18. The method according to claim 16, in, The first CORESET associated with the first search space and the second CORESET associated with the second search space are different time-frequency resources. The first CORESET and the second CORESET are included in the plurality of CORESETs.

19. The method according to claim 16, in, The period of the first search space and the period of the second search space are the same.

20. The method according to claim 16, in, The types of the first search space and the second search space are the same, and The types of the first search space and the second search space are either a public search space or a UE-specific search space.

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