Method, apparatus, and system for transmitting and receiving control channel and data channel in wireless communication system

Abstract

To provide a wireless communication method, apparatus, and system for transmitting and receiving data channels and control channels.SOLUTION: A base station of a wireless communication system is disclosed. The base station of the wireless communication includes a communication module, and a processor. The processor generates a preemption indicator indicating a preempted resource. In this case, the resource indicated by the preemption indicator does not include an Orthogonal Frequency Divisional Multiplexing (OFDM) symbol configured as an uplink (UL) symbol by a radio resource control (RRC) signal. The processor transmits the preemption indicator to a terminal of the wireless system based on a predetermined period.SELECTED DRAWING: Figure 32

Description

Technical Field

[0001] The present invention relates to a wireless communication system. More specifically, the present invention relates to a wireless communication method, apparatus, and system for transmitting and receiving data channels and control channels.

Background Art

[0002] The 3GPP (registered trademark, the same hereinafter) NR (3rd Generation Partnership Project New Radio) system improves the spectral efficiency of the network so that a communication carrier can provide more data and voice services with the given bandwidth. Therefore, the 3GPP NR system is designed to satisfy the requirements for high-speed data and media transmission in addition to large-capacity voice support. The advantages of the NR system are a simple architecture with low operating costs, such as high throughput, low latency, support for FDD (Frequency Division Duplex) and TDD (Time Division Duplex), and an improved end-user environment on the same flat platform.

[0003] For more efficient data processing, Dynamic TDD of the NR system uses a method of varying the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols used for the uplink or downlink according to the data traffic direction of the users in the cell. For example, if the downlink traffic of the cell is larger than the uplink traffic, the base station allocates a large number of downlink OFDM symbols to the slot (or subframe). Information about the slot configuration should be transmitted to the terminal.

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a method for efficiently transmitting signals in a wireless communication system, particularly a cellular wireless communication system, and an apparatus therefor. Another object of the present invention is to provide a method for transmitting and receiving a downlink control channel, an apparatus therefor, and a system therefor.

[0005] The technical problems to be solved by the present invention are not limited to the above technical problems, and other technical problems not mentioned should be clearly understood by those having ordinary knowledge in the technical field to which the present invention pertains from the following description.

Means for Solving the Problems

[0006] A base station of a wireless communication system according to an embodiment of the present invention includes a communication module and a processor for controlling the communication module. The processor generates a preemption indicator indicating pre-empted resources, and transmits the preemption indicator to a terminal of the wireless communication system based on a predetermined period. At this time, the resources indicated by the preemption indicator do not include OFDM (Orthogonal Frequency Divisional Multiplexing) symbols set as uplink (UL) symbols by an RRC (radio resource control) signal.

[0007] The configured OFDM symbols in the terminal are classified into the UL symbols for uplink transmission, the downlink (DL) symbols for downlink transmission, and flexible symbols not set as UL symbols or DL symbols.

[0008] The RRC signal is a cell-specific RRC signal commonly applied to a cell. The preamble indicator divides a plurality of OFDM symbols indicated by the preamble indicator into a plurality of groups, and indicates whether at least one of the one or more OFDM symbols included in each of the plurality of groups is preambled with an OFDM symbol for each of the plurality of groups.

[0009] The number of the plurality of groups is specified in advance. If the number of the plurality of groups is N and the number of the plurality of OFDM symbols indicated by the preamble indicator is S, the processor groups the first mod(S, N) groups of the N groups to include ceil(S / N) OFDM symbols, and the remaining N - mod(S, N) groups are grouped to include floor(S / N) OFDM symbols. The mod(a, b) is a - floor(a / b)*b, the floor(x) is the largest integer that is the same as or smaller than x, and the ceil(x) is the smallest integer that is the same as or larger than x.

[0010] The preamble indicator is monitored by the terminal in integer - slot units. The number of OFDM symbols during the pre - specified period is N_symb*T_INT*2 (μ-μ_INT) where N_symb is the number of OFDM symbols included in a slot, T_INT is the period during which the terminal monitors the preamble indicator, μ_INT is a value that satisfies that the sub - carrier spacing of the carrier on which the preamble indicator is transmitted is 15*2 μ_INT KHz, and μ is a value that satisfies that the sub - carrier spacing of the carrier on which the preamble indicator indicates information regarding preamble is 15*2 μ KHz. The processor sets the values of T_INT, μ, and μ_INT so that N_symb*T_INT*2 (μ-μ_INT) is a natural number.

[0011] The preemption indicator indicates the entire bandwidth of the BWP (bandwidth part) used by the terminal. The BWP is a frequency band in which the terminal transmits and receives with a bandwidth smaller than or equal to the bandwidth of the carrier set for the terminal.

[0012] A terminal of a wireless communication system according to an embodiment of the present invention includes a communication module and a processor that controls the communication module. The processor periodically monitors a preemption indicator that indicates resources preempted from a base station of the wireless communication system. If the preemption indicator is received, the processor determines that the resources indicated by the preemption indicator do not include OFDM symbols set as uplink symbols by an RRC signal, determines resources in which transmission from the base station to the terminal has occurred among the resources scheduled for the terminal based on the preemption indicator, and decodes data received from the base station based on the determination of the resources in which transmission from the base station to the terminal has occurred.

[0013] The OFDM symbols configured in the terminal are classified into the UL symbols for uplink transmission, downlink symbols for downlink transmission, and flexible symbols not set as UL symbols or DL symbols.

[0014] The RRC signal is a cell-common RRC signal commonly applied to a cell. The preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups, and the processor determines whether transmission from the base station to the terminal has occurred in one or more OFDM symbols included in each of the plurality of groups for each of the plurality of groups.

[0015] The number of the plurality of groups is specified in advance. If the number of the plurality of groups is N and the number of OFDM symbols indicated by the preemption indicator is S, the processor determines that the first mod(S, N) groups of the N groups include ceil(S / N) OFDM symbols, and the remaining N - mod(S, N) groups include floor(S / N) OFDM symbols. At this time, mod(a, b) is a - floor(a / b)*b, floor(x) is the largest integer that is the same as or smaller than x, and ceil(x) is the smallest integer that is the same as or larger than x. The processor monitors the preemption indicator in integer slot units.

[0016] The number of OFDM symbols during the period of monitoring the preemption indicator is N_symb*T_INT*2 (μ-μ_INT) where N_symb is the number of OFDM symbols included in a slot, T_INT is the monitoring period of the preemption indicator, μ_INT is a value that satisfies that the sub - carrier spacing of the carrier on which the preemption indicator is transmitted is 15*2 μ_INT KHz, and μ is a value that satisfies that the sub - carrier spacing of the carrier on which the preemption indicator indicates information related to preemption is 15*2 μ KHz. The processor expects values of T_INT, μ, and μ_INT such that N_symb*T_INT*2 (μ-μ_INT) is a natural number.

[0017] The preemption indicator indicates the entire bandwidth of the BWP used by the terminal, and the BWP is a frequency band in which the terminal transmits and receives with a bandwidth smaller than or the same as the bandwidth of the carrier set for the terminal.

[0018] A method for operating a terminal in a wireless communication system according to an embodiment of the present invention includes: periodically monitoring a preemption indicator for indicating preemption resources from a base station of the wireless communication system; if the preemption indicator is received, determining that the resources indicated by the preemption indicator do not include OFDM symbols set as uplink symbols by an RRC signal; if the preemption indicator is received, determining resources among the resources scheduled for the terminal based on the preemption indicator where transmission from the base station to the terminal has occurred; and decoding data received from the base station based on a determination of resources where transmission from the base station to the terminal has occurred.

[0019] The OFDM symbols configured in the terminal are classified into the UL symbols for uplink transmission, downlink symbols for downlink transmission, UL symbols, and flexible symbols not set as UL symbols or DL symbols. The RRC signal is a cell - common RRC signal commonly applied to a cell.

[0020] The preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups. The step of determining resources where transmission from the base station to the terminal has occurred includes determining, for each of the plurality of groups, whether transmission from the base station to the terminal has occurred in one or more OFDM symbols included in each of the plurality of groups.

Advantages of the Invention

[0021] A wireless communication system according to an embodiment of the present invention, particularly a cellular wireless communication system, provides a method for efficiently transmitting signals and an apparatus therefor. Further, a wireless communication system according to an embodiment of the present invention provides a wireless communication method for transmitting and receiving a downlink control channel and an apparatus therefor.

[0022] The effects obtained by the present invention are not limited to the above-described effects, and other effects not mentioned should be clearly understood by those having ordinary knowledge in the technical field to which the present invention pertains from the following description.

Brief Description of the Drawings

[0023]

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DETAILED DESCRIPTION OF THE INVENTION

[0024] The terms used in this specification are selected to be as general as currently widely used in consideration of the functions in the present invention, but this may vary depending on the intentions, conventions of those skilled in the art, or the emergence of new technologies. In some specific cases, there are also those arbitrarily selected by the applicant, and in such cases, the meaning is described in the corresponding invention description part. Therefore, it is clarified that the terms used in this specification should be analyzed based not only on the names of the terms but also on the substantial meanings they have and the content throughout this specification.

[0025] Throughout the specification, when it is stated that a certain configuration is "connected" to another configuration, this includes not only the case where it is "directly connected" but also the case where it is "electrically connected" through other intervening components. Also, when a certain configuration "includes" a specific component, this means that it further includes other components rather than excluding other components, unless otherwise stated to the contrary. In addition, the limiting terms "above" or "below" based on a specific sea area may be appropriately replaced by "more than" or "less than" respectively according to the embodiments.

[0026] The following technologies are used in various wireless connection systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access). CDMA is implemented with radio technologies such as UTRA (Universal Terrestrial Radio Access) and CDMA2000. TDMA is implemented with radio technologies such as GSM (registered trademark) (Global System for Mobile communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA is implemented with radio technologies such as IEEE802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802-20, E-UTRA (Evolved UTRA). UTRA is part of UMTS (Universal Mobile Telecommunication System). 3GPP LTE (Long term evolution) is part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-A (Advanced) is an evolved version of 3GPP LTE. 3GPP NR is a system designed separately from LTE / LTE-A and is a system for supporting eMBB (enhanced Mobile BroadBand), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive Machine Type Communication) services, which are requirements of IMT-2020. For the sake of clarity, the description will focus on 3GPP NR, but the technical idea of the present invention is not limited to this.

[0027] In this specification, unless otherwise specified, the base station refers to a gNB (next generation node B) defined in 3GPP NR. Also, unless otherwise specified, the terminal refers to a UE (user equipment).

[0028] This application claims priority based on Korean Patent Application Nos. 10-2017-0076934 (June 16, 2017), 10-2017-0127516 (September 29, 2017), 10-2017-0129707 (October 11, 2017), 10-2017-0149933 (November 10, 2017), 10-2018-0018903 (February 17, 2018), and 10-2018-0040134 (April 6, 2018), and it is assumed that the examples and descriptions described in each of the above applications serving as the basis for the priority are included in the detailed description of this application.

[0029] In this specification, unless otherwise specified, the base station is referred to as a gNB (next generation nede B) defined in 3GPP NR. Also, unless otherwise specified, the terminal is referred to as a UE (user equipment).

[0030] FIG. 1 is a diagram showing an example of a radio frame structure used in a wireless communication system. Referring to FIG. 1, a radio frame (or radio frame) used in a 3GPP NR system has a length of 10 ms (Δf max N f / 100)*T c ). Also, the radio frame consists of 10 subframes (Subframe, SF) of equal size. Here, Δf max = 480*10 3 HZ, N f = 4096, T c = 1 / (Δf ref * N f、ref ), Δf ref = 15*10 3 Hz, N f、ref= 2048. Ten sub - frames within one radio frame are each assigned numbers from 0 to 9. Each sub - frame has a length of 1 ms and consists of one or more slots depending on the sub - carrier spacing. More specifically, in the 3GPP NR system, the available sub - carrier spacings are 15 * 2 μ kHz, where μ is the sub - carrier spacing configuration factor and has values of μ = 0, 1, 2, 3, 4. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz are used as sub - carrier spacings. One sub - frame with a length of 1 ms contains 2 μ slots. At this time, the length of each slot is 2 -μ ms. The 2 μ slots within one sub - frame are each assigned numbers from 0 to 2 μ - 1. Also, the slots within one sub - frame are each assigned numbers from 0 to 10 * 2 μ - 1. The time resources are divided by at least one of the radio frame number (or radio frame index), sub - frame number (or sub - frame index), and slot number (or slot index).

[0031] Figure 2 is a diagram showing an example of the downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, Figure 2 shows the structure of the resource grid in the 3GPP NR system.

[0032] There is one resource grid per antenna port. Referring to FIG. 2, a slot includes a plurality of OFDM symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. An OFDM symbol may mean one symbol interval. Unless otherwise specified, an OFDM symbol may be simply referred to as a symbol. Referring to FIG. 2, the signal transmitted from each slot is size、μ grid、x *N RB SC composed of N slot Symb sub - carriers and a resource grid consisting of N size、μ grid、x OFDM symbols. Here, if it is a downlink resource grid, x = DL; if it is an uplink resource grid, x = UL. N slot Symb indicates the number of resource blocks (RBs) according to the sub - carrier spacing configuration factor μ (downlink or uplink according to x), and N RB SC indicates the number of OFDM symbols in a slot. N RB SCIt is 12. The OFDM symbol is referred to as a CP-OFDM (cyclic shift OFDM) symbol or a DFT-s-OFDM (Discrete Fourier transform spreading OFDM) symbol by a multiple connection method. The number of OFDM symbols included in one slot may vary depending on the length of the CP (cyclic prefix). For example, if it is a normal CP, one slot includes 14 OFDM symbols, but if it is an extended CP, one slot includes 12 OFDM symbols. In a specific embodiment, the extended CP is used only at a subcarrier interval of 60 kHz. In FIG. 2, for convenience of explanation, a slot consisting of 14 OFDM symbols is exemplified, but the embodiments of the present invention are applied in the same manner to slots having different numbers of OFDM symbols. Referring to FIG. 2, each OFDM symbol includes N size、μ grid、x *N RB SC subcarriers in the frequency domain. The types of subcarriers are divided into data subcarriers for transmitting data, reference signal subcarriers for transmitting a reference signal, and guard bands. The carrier frequency is also called the center frequency.

[0033] An RB is defined as N slot Symb consecutive OFDM symbols (for example, 14) in the time domain and is defined by N RB SC consecutive subcarriers (for example, 12) in the frequency domain. Incidentally, a resource consisting of one OFDM symbol and one subcarrier is called a resource element (RE) or a tone. Therefore, one RB is N slot Symb *N RB SCIt consists of resource elements. Each resource element within the resource grid is uniquely defined by an index pair (k, l) within one slot. k is an index given from 0 to N size、μ grid、x *N RB SC -1 in the frequency domain, and l is an index given from 0 to N slot Symb -1 in the time domain.

[0034] On the other hand, one RB is mapped to one Physical Resource Block (PRB) and one Virtual Resource Block (VRB) respectively. A PRB is defined as N slot Symb (for example, 14) consecutive OFDM symbols in the time domain. Also, a PRB is defined by N RB SC (for example, 12) consecutive subcarriers in the frequency domain. Thus, one PRB consists of N RB SC *N slot Symb resource elements.

[0035] In order for a terminal to receive signals from a base station or transmit signals to a base station, the time / frequency synchronization of the terminal should be aligned with the time / frequency synchronization of the base station. This is because if the base station and the terminal are not synchronized, the terminal cannot determine the time and frequency parameters necessary to perform demodulation of DL signals and transmission of UL signals at the correct time points.

[0036] Each symbol of a radio frame operating in TDD (time division duplex) or unpaired spectrum is composed of at least one of a downlink symbol (DL symbol), an uplink symbol (UL symbol), or a flexible symbol. In FDD (frequency division duplex) or paired spectrum, a radio frame operating on a downlink carrier is composed of downlink symbols or flexible symbols. A radio frame operating on an uplink carrier is composed of uplink symbols or flexible symbols. Downlink transmission can be performed with a downlink symbol, but uplink transmission cannot. Uplink transmission can be performed with an uplink symbol, but downlink transmission cannot. For a flexible symbol, it is determined whether it is used as a downlink symbol or an uplink symbol according to different signals. Information regarding the type of each symbol, that is, whether it is a downlink symbol, an uplink symbol, or a flexible symbol, is composed of a cell-specific (or common) RRC signal. Additionally, information regarding the type of each symbol is composed of an additional UE-specific (or dedicated) RRC signal. The base station uses the cell-specific RRC signal to inform the period of the cell-specific slot configuration, the number of slots having only downlink symbols from the beginning of the period of the cell-specific slot configuration, the number of downlink symbols from the first symbol of the slot immediately following the slot having only downlink symbols, the number of slots having only uplink symbols from the end of the period of the cell-specific slot configuration, and the number of uplink symbols from the last symbol of the slot immediately preceding the slot having only uplink symbols. Here, a symbol not composed of uplink and downlink symbols is a flexible symbol.If the information regarding the symbol type is configured by a specific terminal RRC signal, the base station signals whether the flexible symbol in the cell-specific RRC signal is a downlink symbol or an uplink symbol. At this time, the specific terminal RRC signal changes the downlink symbol or uplink symbol configured by the cell-specific RRC signal to another symbol type. The specific terminal RRC signal is N of the corresponding slot for each slot. slot symb The number of downlink symbols among the symbols, N of the slot slot symb Signals the number of uplink symbols among the symbols. At this time, the downlink symbols of the slot are continuously configured from the first symbol of the slot. Also, the uplink symbols of the slot are continuously configured up to the last symbol of the slot. At this time, in the slot, the symbols not composed of uplink symbols and downlink symbols are flexible symbols. The symbol type configured by the RRC signal is referred to as a semi-static DL / UL configuration. The flexible symbol of the semi-static DL / UL configuration configured by the RRC signal above is indicated as a downlink symbol, an uplink symbol, or a flexible symbol by dynamic SFI (slot format information). At this time, the downlink symbol or uplink symbol configured by the RRC signal is not changed to another symbol type. Table 1 exemplifies the dynamic SFI indicated by the base station to the terminal. In Table 1, D indicates a downlink symbol, U indicates an uplink symbol, and X indicates a flexible symbol. As shown in Table 1, a maximum of two DL / UL switchings are allowed in one slot.

[0037]

Table 1

[0038] FIG. 3 is a diagram for explaining physical channels used in a 3GPP system (e.g., NR) and a general signal transmission method using the physical channels. When the terminal is powered on or newly enters a cell, the terminal performs an initial cell search operation (S301). Specifically, the terminal synchronizes with the base station in the initial cell search. For this purpose, the terminal receives a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) from the base station to synchronize with the base station and obtain information such as the cell ID. Thereafter, the terminal receives a Physical Broadcast Channel from the base station and obtains in-cell broadcast information. The terminal that has completed the initial cell search receives a Physical Downlink Shared Channel (PDSCH) according to a Physical Downlink Control Channel (PDCCH) and information carried on the PDCCH, thereby obtaining more specific system information than the system information obtained through the initial cell search (S302). If the terminal first connects to the base station or there is no radio resource for signal transmission, the terminal performs a random access procedure for the base station (S303 to S306). For this purpose, the terminal transmits a specific sequence as a preamble via a Physical Random Access Channel (PRACH) (S303 to S305) and receives a response message for the preamble from the base station via the PDCCH and the corresponding PDSCH (S304 and S306). In the case of a contention-based RACH, an additional contention resolution procedure is performed. After the above-described procedure, the terminal receives PDCCH / PDSCH as a general uplink / downlink signal transmission procedure (S307), and transmits a Physical Uplink Shared Channel (PUSCH) / Physical Uplink Control Channel (PUCCH) (S308).In particular, the terminal receives downlink control information (DCI) via the PDCCH. The DCI includes control information such as resource allocation information for the terminal. Also, the DCI may have different formats depending on the purpose of use of the DCI. The control information transmitted by the terminal to the base station via the uplink or received by the terminal from the base station includes downlink / uplink ACK / NACK signals, CQI (Channel Quality Indicator), PMI (Precoding Matrix Index), RI (Rank Indicator), etc. In the case of the 3GPP NR system, the terminal transmits control information such as the above-mentioned HARQ-ACK and CSI via the PUSCH and / or PUCCH.

[0039] FIG. 4 is a diagram related to the SS / PBCH block for initial cell connection in the 3GPP NR system. When the terminal is powered on or attempts to newly connect to a cell, it acquires time and frequency synchronization with the cell and performs an initial cell search process. During the initial cell search process, the terminal determines the physical cell identity N of the cell cell IDDetect it. To do so, the terminal receives synchronization signals, such as PSS and SSS, from the base station and synchronizes with the base station. At this time, the terminal acquires information such as cell identifier (identity, ID). Referring to FIG. 4(a), the synchronization signal will be described in more detail. The synchronization signal is divided into PSS and SSS. The PSS is used to obtain time-domain synchronization such as OFDM symbol synchronization and slot synchronization, and / or frequency-domain synchronization. The SSS is used to obtain frame synchronization and cell group ID. Referring to FIG. 4(a) and Table 1, the SS / PBCH block is composed of 20 RBs (= 240 subcarriers) on the frequency axis and 4 OFDM symbols on the time axis. Here, in the SS / PBCH block, in the first OFDM symbol, the SSS is transmitted from subcarriers 56, 57, ··· 182 in the third OFDM symbol. Here, the lowest subcarrier index of the SS / PBCH block is numbered from 0. In the first OFDM symbol where the PSS is transmitted, the remaining subcarriers, that is, subcarriers 0, 1, ··· 55, 183, 184, ··· 239, are not transmitted by the base station with signals. In the third OFDM symbol where the SSS is transmitted, subcarriers 48, 49, ··· 55, 183, 184, ··· 191 are not transmitted by the base station with signals. The base station transmits the PBCH signal to the remaining REs in the SS / PBCH block except for the above signals.

[0040]

Table 2

[0041] The SS indicates a total of 1008 unique physical layer cell identifiers through a combination of 3 PSSs and 336 SSSs. Specifically, the physical layer cell ID is grouped into 336 physical-layer cell-identifier groups, each group containing 3 unique identifiers, such that each physical layer cell ID is part of only one physical-layer cell-identifier group. Therefore, the physical layer cell identifier N cellID = 3N (1) ID + N (2) ID is the number N in the range from 0 to 335 indicating the physical-layer cell-identifier group (1) ID and the number N in the range from 0 to 2 indicating the physical-layer cell-identifier within the physical-layer cell-identifier group (2) ID is uniquely defined thereby. The terminal detects the PSS and identifies one of the three unique physical-layer cell-identifiers. Also, the terminal detects the SSS and identifies one of the 336 physical-layer cell IDs related to the physical-layer cell-identifier. The PSS signal is as follows.

[0042]

Number

[0043] Here x(i + 7) = (x(i + 4)+x(i))mod2 where [x(6) x(5) x(4) x(3) x(2) x(1) x(0)] = [1 1 1 0 1 1 0] is given. The SSS is as follows.

[0044]

Number

[0045] Here x0(i + 7) = (x0(i + 4)+x0(i))mod2 x1(i + 7) = (x1(i + 1)+x1(i))mod2 where [x0(6) x0(5) x0(4) x0(3) x0(2) x0(1) x0(0)] = [0 0 0 0 0 0 1] [x1(6) x1(5) x1(4) x1(3) x1(2) x1(1) x1(0)] = [0 0 0 0 0 0 1] It is given by

[0046] A wireless frame with a 10 ms duration is divided into two half - frames with a 5 ms duration. Referring to Figure 4(b), the slots in each half - frame where the SS / PBCH block is transmitted will be described. The slot where the SS / PBCH block is transmitted is one of Case A, B, C, D, or E. In Case A, the sub - carrier spacing is 15 kHz, and the starting point of the SS / PBCH block is {2, 8}+14*n symbols. At this time, for carrier frequencies below 3 GHz, n = 0, 1. For carrier frequencies above 3 GHz and below 6 GHz, n = 0, 1, 2, 3. In Case B, the sub - carrier spacing is 30 kHz, and the starting point of the SS / PBCH block is {4, 8, 16, 20}+28*n. At this time, for carrier frequencies below 3 GHz, n = 1. For carrier frequencies above 3 GHz and below 6 GHz, n = 0, 1. In Case C, the sub - carrier spacing is 30 kHz, and the starting point of the SS / PBCH block is {2, 8}+14*n. At this time, for carrier frequencies below 3 GHz, n = 0, 1. For carrier frequencies above 3 GHz and below 6 GHz, n = 0, 1, 2, 3. In Case D, the sub - carrier spacing is 120 kHz, and the starting point of the SS / PBCH block is {4, 8, 16, 20}+28*n. At this time, for carrier frequencies above 6 GHz, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In Case E, the sub - carrier spacing is 240 kHz, and the starting point of the SS / PBCH block is {8, 12, 16, 20, 32, 36, 40, 44}+56*n. At this time, for carrier frequencies above 6 GHz, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0047] FIG. 5 relates to procedures for control information and control channel transmission in a 3GPP NR system. Referring to FIG. 5(a), the base station adds a CRC (Cyclic Redundancy Check) masked (e.g., XOR operation) with an RNTI (Radio Network Temporary Identifier) to the control information (e.g., DCI) (S502). The base station scrambles the CRC with an RNTI value determined by the purpose / target of each control information. The common RNTIs used by one or more terminals include at least one of SI-RNTI (System Information RNTI), P-RNTI (Paging RNTI), RA-RNTI (Random Access RNTI), and TPC-RNTI (Transit Power Control RNTI). Also, the terminal-specific RNTIs include at least one of C-RNTI (Cell temporary RNTI), and SPS C-RNTI (Semi-Persistent Scheduling). Next, after the base station performs channel coding (e.g., polar coding) (S504), it performs rate-matching according to the amount of resource(s) used for PDCCH transmission (S506). Next, the base station multiplexes the DCI(s) based on the PDCCH structure of the CCE (Cntrol Channel Element) substrate (S508), and then applies additional processes (e.g., scrambling, modulation (e.g., QPSK), interleaving) (S910) to the multiplexed DCI(s) and then maps them to the resources to be transmitted. A CCE is the basic resource unit for the PDCCH, and one CCE consists of a plurality (e.g., 6) of REGs (Resource Element Group). One REG consists of a plurality (e.g., 12) of REs. The number of CCEs used for one PDCCH is defined as the aggregation level. In the 3GPP NR system, 1, 2, 4, 8, 16 are used.Figure 5(b) is a diagram related to the CCE aggregation level and the multiplexing of PDCCH, showing the types of CCE aggregation levels used for one PDCCH and the CCE(s) transmitted from the control region thereby.

[0048] Figure 6 is a diagram showing the CORESET in which PDCCH is transmitted in the 3GPP NR system. The CORESET is the time - frequency resource in which the PDCCH, which is a control signal of the terminal, is transmitted. Referring to Figure 6, instead of receiving all frequency bands and attempting to demultiplex the PDCCH "complex", the terminal receives only the time - frequency resources defined as the CORESET and demultiplexes the PDCCH mapped within the CORESET. The base station configures one or more CORESETs for each cell for the terminal. The CORESET consists of up to three consecutive symbols on the time axis. Also, the CORESET is configured continuously or discontinuously in units of 6 PRBs on the frequency axis. In the embodiment of Figure 5, CORESET#1 consists of consecutive PRBs, and CORESET#2 and CORESET#3 consist of discontinuous PRBs. The CORESET can be located in any symbol within the slot. For example, CORESET#1 in Figure 5 starts from the first symbol of the slot, CORESET#2 starts from the fifth symbol of the slot, and CORESET#9 starts from the ninth symbol of the slot.

[0049] FIG. 7 is a diagram related to the setting of the PDCCH search space in the 3GPP NR system. To transmit the PDCCH to the terminal, there is at least one or more search spaces in each CORESET. In the present invention, the search space is a set of all time-frequency resources (hereinafter, PDCCH candidates) where the PDCCH of the terminal can be transmitted. The search space includes a common search space that all terminals in the 3GPP NR should commonly search, and a terminal-specific or UE-specific search space that a specific terminal should search. The common search space is set to monitor the PDCCH that is set so that all terminals in the cells belonging to the same base station commonly search. The terminal-specific search space is set for each terminal to monitor the PDCCH assigned to each terminal at different search space positions according to the terminal. The terminal-specific search space may be assigned with the search spaces partially overlapping among terminals due to the limited control region that can be assigned to the PDCCH. Monitoring the PDCCH includes blindly decoding the PDCCH candidates in the search space. When the blind decoding is successful, it is expressed that the PDCCH is (successfully) detected / received, and when the blind decoding fails, it is expressed that the PDCCH is not detected / not received, or not successfully detected / received.

[0050] For the sake of convenience in description, in order to transmit uplink scheduling information or downlink scheduling information to one or more terminals, a PDCCH scrambled with a group common (GC) RNTI (or common control RNTI, CC-RNTI) that is already known is referred to as a (UE) group common (GC) PDCCH, or a common PDCCH. Also, in order to transmit uplink scheduling information or downlink scheduling information to a specific terminal, a PDCCH scrambled with a user-specific RNTI that the specific terminal already knows is referred to as a user-specific (US) PDCCH.

[0051] The PDCCH notifies each terminal or terminal group of at least one of information regarding resource allocation (DL Grant) of the PCH (Paging channel) and DL-SCH (Downlink-shared channel) which are transmission channels, resource allocation (Uplink Grant) of the UL-SCH, and HARQ information. The base station transmits the PCH transmission block and the DL-SCH transmission block via the PDSCH. The base station transmits data excluding specific control information or specific service data via the PDSCH. Also, the terminal receives data excluding specific control information or specific service data via the PDSCH.

[0052] The base station includes in the PDCCH and transmits information regarding to which terminal (one or more terminals) the PDSCH data is to be transmitted and how the corresponding terminal should receive and decode the PDSCH. For example, assume that a specific PDCCH is CRC masked with an RNTI named "A" and transmitted via a specific subframe with information regarding the data to be transmitted using a radio resource named "B" (e.g., frequency position) and a DCI format named "C", i.e., transmission format information (e.g., transmission block size, modulation method, coding information). In this case, the terminals in the cell monitor the PDCCH using the RNTI information they possess. If there is one or more terminals with the "A" RNTI, the corresponding terminals receive the PDCCH and receive the PDSCH indicated by "B" and "C" based on the information of the received PDCCH. Table 2 relates to the PUCCH (physical uplink control channel) used in a wireless communication system.

[0053]

Table 3

[0054] The PUCCH is used to transmit the following control information. - SR (Scheduling Request): Information used to request uplink UL-SCH resources.

[0055] - HARQ-ACK: Response to PDCCH (indicating DL SPS release) and / or response to downlink data packets on PDSCH. It indicates whether PDCCH or PDSCH has been successfully received. HARQ-ACK responses include positive ACK (simply ACK), negative ACK (hereinafter NACK), DTX (Discontinuous Transmission), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ ACK / NACK, ACK / NACK. Generally, ACK is represented as 1 and NACK is represented as 0 in the expression.

[0056] - CSI (Channel State Information): Feedback information for the downlink channel. It is generated by the terminal based on the CSI-RS (Reference Signal) transmitted by the base station. MIMO (Multi Input Multi Output)-related feedback information includes RI (Rank Indicator) and PMI (Precoding Matrix Indicator). CSI is divided into CSI part 1 and CSI part 2 according to the information indicated by CSI.

[0057] In the 3GPP NR system, five PUCCH formats are used to support various service scenarios, various channel environments, and frame structures.

[0058] PUCCH format0 is a format for transmitting 1-bit or 2-bit HARQ-ACK information. PUCCH format0 is transmitted via 1 OFDM symbol or 2 OFDM symbols on the time axis and 1 PRB on the frequency axis. If PUCCH format0 is transmitted in 2 OFDM symbols, the same sequence is transmitted on different PRBs in the two symbols. Through this, the terminal obtains a frequency diversity gain. More specifically, the terminal transmits M bit bits UCI (Mbit determines the value m of the cyclic shift by (m = 1 or 2), and cyclically shifts the base sequence of length 12 by the determined value m cs and maps the cyclically shifted sequence to 12 REs of 1 PRB of 1 OFDM symbol for transmission. The number of available cyclic shifts for the terminal is 12, and when M cs = 1, when the terminal transmits UCI0 and UCI1, the terminal arranges the difference between the values of the two cyclic shifts to be 6. Also, when M bit = 2 and the terminal transmits UCI00, UCI01, UCI11, UCI10, the terminal arranges the difference between the values of the four cyclic shifts to be 3. bit = 2, and if the terminal transmits UCI00, UCI01, UCI11, UCI10, the terminal arranges the difference between the values of the four cyclic shifts to be 3.

[0059] PUCCH format1 transmits 1-bit or 2-bit HARQ-ACK information. PUCCH format1 is transmitted in 1 PRB on the frequency axis and in OFDM symbols consecutive on the time axis. Here, the number of OFDM symbols occupied by PUCCH format1 is one of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14. More specifically, when M bit = 1, the UCI is BPSK modulated. The terminal when M bit = 2 modulates the UCI by QPSK (Quadrature Phase Shift Keying) to generate a complex valued symbol d(0), and multiplies the generated d(0) by a sequence of length 12 to obtain a signal. The terminal spreads the obtained signal by time-axis OCC (orthogonal cover code) on the even-numbered OFDM symbols to which PUCCH format1 is allocated and transmits it. PUCCH format1 determines the maximum number of different terminals multiplexed on the same PRB according to the length of the OCC used. On the last OFDM symbol of PUCCH format1, DMRS (Demodulation RS) is spread by OCC and mapped.

[0060] PUCCH format 2 transmits UCI (Uplink Control Information) exceeding 2 bits. PUCCH format 2 is transmitted on 1 OFDM symbol or 2 OFDM symbols on the time axis and 1 PRB on the frequency axis. If PUCCH format 2 is transmitted on two OFDM symbols, the same sequence is transmitted on different PRBs via the two OFDM symbols. Through this, the terminal obtains a frequency diversity gain. More specifically, M bit bits UCI (M bit >2) is bit-level scrambled, QPSL modulated and mapped to the PRB(s) of the OFDM symbol. Here, the number of PRBs is any one of 1, 2, ···, 16.

[0061] PUCCH format 3 or PUCCH format 4 transmits UCI exceeding 2 bits. PUCCH format 3 or PUCCH format 4 is transmitted via consecutive OFDM symbols on the time axis and 1 PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 is any one of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14. Specifically, the terminal bit bits UCI (M bit >2) is modulated with π / 2-BPSK (Binary Phase Keying) or QPSK to generate complex symbols d(0), ···, d(M symb -1). The terminal does not apply block-wise spreading to PUCCH format 3. However, the terminal applies block-wise spreading to 1 RB (12 subcarriers) using a length-12 PreDFT-OCC so that PUCCH format 4 has two or four multiplexing capacities. The terminal transmit precodes (or DFT-precodes) the spread signal, maps it to each RE, and transmits the spread signal.

[0062] At this time, the number of PRBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 is determined according to the length of UCI transmitted by the terminal and the maximum code rate. If the terminal uses PUCCH format 2, the terminal transmits both HARQ-ACK information and CSI information via the PUCCH. If the number of PRBs that the terminal can transmit is larger than the maximum number of PRBs that can be used by PUCCH format 2, PUCCH format 3, or PUCCH format 4, the terminal does not transmit some UCI information according to the priority of the UCI information and transmits only the remaining UCI information.

[0063] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured via an RRC signal so as to indicate frequency hopping within a slot. When frequency hopping is configured, the PRB indexes for frequency hopping are configured by the RRC signal. If PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted over the Nth OFDM symbol on the time axis, the first hop has floor(N / 2) OFDM symbols and the second hop has ceiling(N / 2) OFDM symbols.

[0064] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured to be repeatedly transmitted in a plurality of slots. At this time, the number of slots K in which the PUCCH is repeatedly transmitted is configured by the RRC signal. The repeatedly transmitted PUCCH should start from the OFDM symbol at the same position within each slot and have the same length. If even one of the OFDM symbols of the slot in which the terminal should transmit the PUCCH is indicated as a DL symbol by the RRC signal, the terminal does not transmit the PUCCH in the corresponding slot and extends the transmission to the next slot.

[0065] In the 3GPP NR system, the terminal performs transmission and reception using a bandwidth smaller than or the same as that of the carrier (or cell). For this purpose, the terminal constitutes a Bandwidth part (BWP) consisting of a part of the continuous bandwidth within the carrier bandwidth. A terminal operating by TDD or operating in an unpaired spectrum constitutes a maximum of 4 DL / UL BWP pairs for one carrier (or cell). Also, the terminal activates one DL / UL BWP pair. A terminal operating by FDD or operating in a paired spectrum constitutes a maximum of 4 DL BWPs for the downlink carrier (or cell) and a maximum of 4 UL BWPs for the uplink carrier (or cell). The terminal activates one DL BWP and one UL BWP for each carrier (or cell). The terminal does not receive or attempt to receive in time-frequency resources other than the activated BWP. The activated BWP is referred to as the active BWP.

[0066] The base station uses DCI to instruct the terminal to move from one BWP to another. The terminal moving from one BWP to another indicates deactivating the BWP used by the terminal and activating a new BWP. In a carrier (or cell) operating in TDD, the base station includes a BPI (Bandwidth part indicator) that indicates the BWP to be activated in the DCI for scheduling PDSCH or PUSCH in order to change the DL / UL BWP pair of the terminal. The terminal receives the DCI for scheduling PDSCH or PUSCH and identifies the DL / UL BWP pair to be activated based on the BPI. In the case of a downlink carrier (or cell) operating in FDD, the base station includes a BPI that notifies the BWP to be activated in the DCI for scheduling PDSCH to change the DL BWP of the terminal. In the case of an uplink carrier (or cell) operating in FDD, the base station includes a BPI that indicates the BWP to be activated in the DCI for scheduling PDSCH to change the UL BWP of the terminal. Hereinafter, the carrier aggregation technique will be described. FIG. 6 is a conceptual diagram for explaining carrier aggregation.

[0067] Carrier aggregation means a method in which a wireless communication system uses a frequency block composed of uplink resources (or component carriers) and / or downlink resources (or component carriers), or a plurality of cells (in a logical sense), as one large logical frequency band in order to use a wider frequency band. Hereinafter, for convenience of explanation, the term "component carrier" will be used uniformly.

[0068] Referring to FIG. 8, as an example of the 3GPP NR system, the overall system bandwidth includes up to 16 component carriers, and each component carrier has a bandwidth of up to 400 MHz. A component carrier includes one or more consecutive sub-carriers that are physically continuous. FIG. 8 shows that each component carrier has the same bandwidth, but this is only an example, and each component carrier may have a different bandwidth. Also, although each component carrier is shown as adjacent to each other on the frequency axis, the drawing is shown in a logical outer surface, and each component carrier may be physically adjacent to or separated from each other.

[0069] In each component carrier, different center frequencies are used. Also, in physically adjacent component carriers, a common center carrier is used. In the embodiment of FIG. 8, assuming that all component carriers are physically adjacent, center carrier A is used for all component carriers. Also, assuming that each component carrier is not physically adjacent, center carrier A and center carrier B are used in each component carrier.

[0070] If the overall system bandwidth is extended by carrier aggregation, the frequency band used for communication with each terminal is defined in component carrier units. Terminal A can use 100 MHz, which is the overall system bandwidth, and communicates using all five component carriers. Terminals B1 to B5 can only use a bandwidth of 20 MHz and communicate using one component carrier. Terminals C1 and C2 can only use a bandwidth of 40 MHz and communicate using two component carriers each. The two component carriers may or may not be logically / physically adjacent. Terminal C1 shows the case of using two non-adjacent component carriers, and Terminal C2 shows the case of using two adjacent component carriers.

[0071] FIG. 9 is a diagram for explaining single-carrier communication and multi-carrier communication. In particular, FIG. 9(a) shows the sub-frame structure of a terminal carrier, and FIG. 9(b) shows the sub-frame structure of a multi-carrier.

[0072] Referring to FIG. 9(a), a general wireless communication system transmits or receives data via one DL band and one corresponding UL band (in the case of the frequency division duplex (FDD) mode). In other specific embodiments, the wireless communication system divides a radio frame in the time domain into an uplink time unit and a downlink time unit, and transmits or receives data via the uplink / downlink time unit (in the case of the time division duplex (TDD) mode). Referring to FIG. 9(b), three 20 MHz CCs are aggregated in UL and DL respectively to support a bandwidth of 60 MHz. Each CC is adjacent or non-adjacent to each other in the frequency domain. FIG. 9(b) shows the case where the bandwidths of the UL CC and the DL CC are both the same and symmetric for convenience, but the bandwidth of each CC may be determined independently. Also, asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is possible. The DL / UL CCs limited to a specific UE via RRC are referred to as the configured serving UL / DL CCs in a specific UL.

[0073] The base station uses the communication with the terminal by activating some or all of the serving CCs configured in the terminal, or deactivating some of the CCs. The base station changes the CCs to be activated / deactivated and changes the number of CCs to be activated / deactivated. When the base station assigns the CCs available to the terminal on a cell-specific or terminal-specific basis, at least one of the CCs once assigned is not deactivated unless the CC assignment for the terminal is completely reconfigured or the terminal performs a handover. One CC that is not deactivated in the terminal is called the Primary CC (PCC), and the CCs that the base station can freely activate / deactivate are called the Secondary CCs (SCCs). The PCC and SCCs may be classified based on control information. For example, specific control information may be set to be transmitted and received only via a specific CC, and such a specific CC may be called the PCC, and the remaining CC(s) may be called the SCC(s).

[0074] On the other hand, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of downlink resources (DL resources) and uplink resources (UL resources), that is, a combination of DL CC and UL CC. A cell consists of DL resources alone or a combination of DL resources and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of the DL resources (or DL CC) and the carrier frequency of the UL resources (or UL CC) is indicated by the system information. For a UE in the RRC_CONNECTED state but without carrier aggregation configured or not supporting carrier aggregation, there is only one serving cell composed only of the PCell.

[0075] As described above, the term "Cell" used in carrier aggregation is distinguished from the term "Cell" that refers to a certain geographical area where communication services are provided by one base station or one antenna group. In order to distinguish between the "Cell" that refers to a certain geographical area and the "Cell" of carrier aggregation, in the present invention, the "Cell" of carrier aggregation is referred to as a CC, and the "Cell" of the geographical area is referred to as a Cell.

[0076] FIG. 10 is a diagram showing an example to which a cross-carrier scheduling technique is applied. In particular, in FIG. 10, the number of allocated cells (or component carriers) is three, and the cross-carrier scheduling technique is performed using the CIF as described above. Here, it is assumed that the downlink cell #0 is a downlink primary component carrier (that is, a Primary Cell, PCell), and the remaining component carriers #1 and #2 are secondary component carriers (that is, Secondary Cells, SCell).

[0077] In the present invention, a method for effectively managing uplink resources for a primary component carrier (primary component carrier or Primary Cell or PCell) or a secondary component carrier (secondary component carrier or SCell) while a terminal performs carrier aggregation operation is proposed. Hereinafter, the case where a terminal operates by combining two component carriers will be described, but it is obvious that the method is also applicable to the case where three or more component carriers are combined.

[0078] FIGS. 9 to 10 are exemplified mainly based on the subframe structure of the 3GPP LTE-A system, but are also applicable to the 3GPP NR system. In the 3GPP NR system, the subframes in FIGS. 9 to 10 may be replaced with slots.

[0079] Hereinafter, the present invention will be described. For the sake of understanding the description, each content will be separately described in examples, but each example may be used in combination with each other.

[0080] FIG. 11 is a block diagram showing the configurations of a terminal and a base station according to an embodiment of the present invention. As shown in the figure, a terminal 100 according to an embodiment of the present invention includes a processor 110, a communication unit 120, a memory 130, a user interface unit 140, and a display unit 150.

[0081] First, the processor 110 executes various instructions or programs and processes data inside the terminal 100. Also, the processor 100 controls the overall operation including each unit of the terminal 100 and controls the transmission and reception of data between the units. Here, the processor 110 is configured to perform operations according to the embodiments described in the present invention. For example, the processor 110 may receive slot configuration information, determine the configuration of the slot based on it, and perform communication according to the determined slot configuration information.

[0082] Next, the communication module 120 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN connection using a wireless LAN. For this purpose, the communication module 120 includes a plurality of network interface cards such as cellular communication interface cards 121, 122, and a wireless LAN interface card 123 in a built-in or external form. In the drawing, the communication module 120 is shown as an integrated module, but each network interface card may be arranged independently according to the circuit configuration or application, different from the drawing.

[0083] The cellular communication interface card 121 transmits and receives wireless signals with at least one of the base station 200, external device, and server via a mobile communication network, and provides a cellular communication service using a first frequency band based on the instructions of the processor 110. Here, the wireless signal includes various forms of data or information such as a voice call signal, a video call signal, or a mail / multimedia message. The cellular communication interface card 121 includes at least one NIC module that utilizes an LTE-Licensed frequency band. The at least one NIC module independently performs cellular communication with at least one of the base station 200, external device, and server according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0084] The cellular communication interface card 122 transmits and receives wireless signals with at least one of the base station 200, external device, and server via a mobile communication network, and provides a cellular communication service using a second frequency band based on the instructions of the processor 110. The cellular communication interface card 122 includes at least one NIC module that utilizes an LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a 2.4 GHz or 5 GHz band.

[0085] The wireless LAN interface card 123 transmits and receives wireless signals with at least one of the base station 200, external device, and server via a wireless LAN connection, and provides a wireless LAN service using a second frequency band based on the instructions of the processor 110. The wireless LAN interface card 123 includes at least one NIC module that utilizes a wireless LAN frequency band. For example, the wireless LAN frequency band may be an Unlicensed radio band such as a 2.4 GHz or 5 GHz band. The at least one NIC module independently performs cellular communication with at least one of the base station 200, external device, and server according to the wireless LAN standard or protocol of the frequency band supported by the corresponding NIC module.

[0086] Next, the memory 130 stores a control program used in the terminal 100 and various data thereby. Such a control program includes a predetermined program necessary for the terminal 100 to perform wireless communication with at least one of the base station 200, an external device, and a server.

[0087] Next, the user interface 140 includes various forms of input / output means provided in the terminal 100. That is, the user interface unit 140 receives a user input using various input means, and the processor 110 controls the terminal 100 based on the received user input. Further, the user interface 140 performs an output based on an instruction of the processor 110 using various output means.

[0088] Next, the display unit 150 outputs various images on the display screen. The display unit 150 outputs various display objects such as content performed by the processor 110 or a user interface based on a control instruction of the processor 110.

[0089] Also, the base station 200 according to an embodiment of the present invention includes a processor 210, a communication module 220, and a memory 230.

[0090] First, the processor 210 executes various instructions or programs and processes data inside the base station 200. Also, the processor 210 controls the overall operation including each unit of the base station 200 and controls the transmission and reception of data between the units. Here, the processor 210 is configured to perform operations according to the embodiments described in the present invention. For example, the processor 210 may signal slot configuration information and perform communication according to the signaled slot configuration information.

[0091] Next, the communication module 220 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN connection using a wireless LAN. For this purpose, the communication module 120 includes a plurality of network interface cards such as cellular communication interface cards 221 and 222, and a wireless LAN interface card 223 in a built-in or external form. In the drawings, the communication module 220 is shown as an integrated module, but each network interface card may be independently arranged according to the circuit configuration or application, different from the drawings.

[0092] The cellular communication interface card 221 transmits and receives wireless signals with at least one of the terminal 100, the external device, and the server described above using a mobile communication network, and provides a cellular communication service in a first frequency band based on an instruction from the processor 210. Here, the wireless signal includes various forms of data or information such as a voice call signal, a video call signal, or a mail / multimedia message. The cellular communication interface card 221 includes at least one NIC module that uses an LTE-Licensed frequency band. The at least one NIC module independently performs cellular communication with at least one of the terminal 100, the external device, and the server according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0093] The cellular communication interface card 222 transmits and receives wireless signals with at least one of the terminal 100, an external device, and a server via a mobile communication network, and provides a cellular communication service in a second frequency band based on an instruction from the processor 210. The cellular communication interface card 222 includes at least one NIC module that utilizes an LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a 2.4 GHz or 5 GHz band. According to an embodiment of the present invention, at least one NIC module independently performs cellular communication with at least one of the terminal 100, an external device, and a server according to a cellular communication standard or protocol of a frequency band supported by the corresponding NIC module.

[0094] The wireless LAN interface card 223 transmits and receives wireless signals with at least one of the terminal 100, an external device, and a server via a wireless LAN connection, and provides a wireless LAN service in a second frequency band based on an instruction from the processor 210. The wireless LAN interface card 223 includes at least one NIC module that utilizes a wireless LAN frequency band. For example, the wireless LAN frequency band may be an Unlicensed radio band such as a 2.4 GHz or 5 GHz band. At least one NIC module independently performs wireless communication with at least one of the terminal 100, an external device, and a server according to a wireless LAN standard or protocol of a frequency band supported by the corresponding NIC module.

[0095] The terminal 100 and the base station 200 shown in FIG. 11 are block diagrams according to an embodiment of the present invention, and the blocks shown separately are logically distinguished device elements. Therefore, the above-described device elements are attached to one chip or a plurality of chips according to the device design. In addition, some configurations of the terminal 100, for example, the user interface unit 140 and the display unit 150, etc., may be selectively provided in the terminal 100. Also, the user interface 140 and the display unit 150, etc., may be additionally provided in the base station 200 if necessary.

[0096] In this specification, configuring a terminal indicates configuration by a base station. Specifically, the base station transmits a channel or a signal to the terminal and sets the values of the parameters used in the operation of the terminal or the radio communication system.

[0097] FIG. 12 is a diagram showing an example of a CORESET according to an embodiment of the present invention in an NR system. As described above, the CORESET is the time-frequency resource in which the PDCCH, which is a control signal of the terminal, is transmitted. Also, a search space is mapped to one CORESET. Therefore, instead of monitoring all frequency bands to receive the PDCCH, the terminal monitors the time-frequency region designated by the CORESET and decodes the PDCCH mapped to the CORESET.

[0098] In a specific embodiment, there is one CORESET per cell. At this time, a terminal connected to the corresponding cell receives PDCCH from one CORESET. In other specific embodiments, as shown in FIG. 12, there may be multiple CORESETs in one cell. At this time, a terminal connected to the corresponding cell monitors one or more CORESETs. Specifically, a terminal connected to a cell is set by the base station to monitor one or more CORESETs. In addition, multiple CORESETs assigned to one terminal are set to overlap in time-frequency resources with each other.

[0099] The terminal determines the time-frequency region occupied by the CORESET assigned by the base station to the terminal in the current slot. However, the terminal may not be able to determine the time-frequency region occupied by a CORESET not assigned by the base station to the terminal in the current slot, or may not be able to determine it without additional signaling. In addition, the terminal may not be able to determine the time-frequency resources occupied by the PDSCH dynamically assigned by the CORESET in a slot at a time later than the current time assigned by the base station to the terminal.

[0100] FIG. 13 is a diagram showing an example of a BWP set for a terminal according to an embodiment of the present invention. As described above, the terminal performs reception and transmission via a BWP having a frequency bandwidth smaller than or the same as the frequency bandwidth of a carrier (or cell). In a specific embodiment, one or more BWPs are set for the terminal. If multiple BWPs are set for the terminal, the frequency bands of the multiple BWPs do not overlap with each other. Also, one or more BWPs may be set for the terminal. If multiple BWPs are set for the terminal, the multiple BWPs include a BWP that includes a frequency band overlapping with another BWP of the multiple BWPs. Fig. 13(a) shows a case where the frequency bands of multiple BWPs do not overlap with each other when multiple BWPs are set for the terminal. Fig. 13(b) shows a case where multiple BWPs include a BWP that includes a frequency band overlapping with another BWP of the multiple BWPs when multiple BWPs are set for the terminal. If multiple BWPs are set for the terminal, the terminal performs transmission and reception using one of the multiple BWPs. This will be described in detail with reference to Fig. 14.

[0101] Fig. 14 is a diagram showing a BWP set for a terminal and an example of a CORESET for the BWP according to an embodiment of the present invention. If multiple BWPs are set for the terminal, each of the multiple CORESETs for each of the multiple BWPs is located within the time-frequency resource region occupied by the corresponding BWP. If multiple BWPs are set for the terminal, at least one CORESET is set for the terminal from each of the multiple BWPs. When the multiple BWPs are set so as not to overlap with each other and when the multiple BWPs are set so as to overlap with each other, the CORESET for each of the multiple BWPs exists within the PRB occupied by the corresponding BWP. Also, when the multiple BWPs are set so as to overlap with each other, for the CORESET for each of the multiple BWPs, the PRB occupied by the CORESET corresponding to any one of the multiple BWPs overlaps with the PRB occupied by the corresponding BWP and other BWPs among the multiple BWPs.

[0102] In the embodiment of FIG. 14(a), the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2) are set so as not to overlap with each other. The first CORESET (CORESET #1) corresponding to the first BWP (Bandwidth part #1) exists within the PRBs occupied by the first BWP (Bandwidth part #1). Also, the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2) exists within the PRBs occupied by the second BWP (Bandwidth part #2). In the embodiment of FIG. 14(b), the second BWP (Bandwidth part #2) includes the entire frequency band indicated by the first BWP (Bandwidth part #1). The first CORESET (CORESET #1) corresponding to the first BWP (Bandwidth part #1) exists within the PRBs occupied by the first BWP (Bandwidth part #1). Also, the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2) exists within the PRBs occupied by the second BWP (Bandwidth part #2). At this time, the PRBs occupied by the second CORESET (CORESET #2) overlap with the PRBs occupied by the first BWP (Bandwidth part #1).

[0103] In order to implement various functions in the NR system, the base station uses the time - frequency resource region scheduled for any one terminal for other purposes and indicates that the corresponding time - frequency resource region has been used for other purposes. The base station using the time - frequency resource region scheduled for any one terminal for other purposes is called preemption. Also, the terminal whose scheduled time - frequency resource is punctured is called an impacted terminal. Also, the terminal assigned the time - frequency resource scheduled for other purposes is called a preempting terminal. The base station according to the embodiment of the present invention performs the preemption operation as follows.

[0104] Specifically, the base station multiplexes data that is not sensitive to the delay time for the same terminal or different terminals and data that is sensitive to the delay time, and transmits the multiplexed data. The data that is not sensitive to the delay time is the data for the eMBB service described above. Also, the data that is sensitive to the delay time is the data for the URLLC service described above. Further, the base station schedules the data that is not sensitive to the delay time based on slots. At this time, the base station schedules the data that is sensitive to the delay time in time intervals having a duration shorter than the duration of the slot. A time interval having a duration shorter than the duration of the slot is referred to as a mini-slot. The number of OFDM symbols assigned to one slot can vary depending on the subcarrier spacing. If 15 kHz is used for the reference subcarrier spacing, one slot includes 7 or 14 OFDM symbols. If 30 kHz is used for the reference subcarrier spacing, one slot includes 14 OFDM symbols. Since the duration of the mini-slot is smaller than the duration of the slot as described above, the mini-slot includes from 1 OFDM symbol to 1 less OFDM symbol than the number of OFDM symbols included in the slot. In a specific embodiment, the base station schedules the data that is sensitive to the delay time in units of 2 OFDM symbols or 4 OFDM symbols. In another specific embodiment, the base station schedules the data that is sensitive to the delay time in units of 7 OFDM symbols in consideration of the duration of the slot. This is because the payload size of the data that is not sensitive to the delay time is relatively large and there is less need to be scheduled immediately as the required delay time is longer. Also, this is because the payload size of the data that is sensitive to the delay time is relatively small and there is a greater need to be scheduled immediately as the required delay time is shorter. In such an embodiment, the base station dynamically allocates time-frequency resources for the service sensitive to the delay time and time-frequency resources for the service not sensitive to the delay time in order to increase the frequency efficiency and reduce the delay time. Therefore, the base station performs preemption.

[0105] When the base station performs preemption, for the impacted terminals that have been scheduled earlier, the base station transmits other data to a part of the resources that the terminals assume for reception through preemption. Therefore, the data in the resources actually transmitted by the base station to the impacted terminals may be different from the resources that the terminals assume for reception. The impacted terminals receive and decode the data corrupted by the data transmitted by the base station through preemption. Eventually, the decoding performance of the terminals deteriorates, and there is a risk of a serious decline in the performance of the impacted terminals. To prevent this, the base station signals to the impacted terminals which time-frequency resources have been preempted.

[0106] Based on the signaling for preemption, the terminal decodes the data that the base station intends to transmit to the terminal. Specifically, the terminal assumes whether the data transmission intended from the base station to the terminal is possible based on the signaling for preemption. At this time, the terminal decodes the data received from the base station in the corresponding resources based on the resources assuming the transmission of the data intended from the base station to the terminal and the resources assuming that there is no transmission of the data intended for the terminal. At this time, the data includes at least one of a data channel and a control channel.

[0107] The method of preemption signaling transmitted from the base station to the terminal will be described in detail with reference to FIGS. 15 to 30. Also, the method of monitoring the group common PDCCH or the terminal-specific PDCCH for obtaining the preemption indicator in the terminal will be described with reference to FIGS. 15 to 20.

[0108] FIG. 15 is a diagram showing a method by which a terminal monitors a preemption indicator based on a BWP and a CORESET corresponding to the BWP according to an embodiment of the present invention. The base station transmits a preemption indicator to the terminal, which indicates, using a control channel, which time-frequency resources have been preempted. The preemption indicator described in this specification refers to a DCI format that is CRC scrambled with an INT-RNTI. Also, the control channel is the PDCCH described above. Specifically, the control channel is a group common PDCCH or a UE specific PDCCH. If the base station transmits a preemption indicator using a group common PDCCH, the base station scrambles the group common PDCCH with a group common RNTI. At this time, the group common RNTI is a value shared by a plurality of terminals that monitor the corresponding group common PDCCH. If the preemption indicator is included in and transmitted by a specific-terminal PDCCH, the specific-terminal PDCCH is scrambled with a specific-terminal RNTI, and this specific-terminal RNTI is a unique value of the terminal that monitors the corresponding specific-terminal PDCCH. In a specific embodiment, the terminal applies the preemption-related information indicated by the preemption indicator included in the group common PDCCH only to the BWP corresponding to the CORESET through which the PDCCH is transmitted. For example, the terminal may blindly decode a group common PDCCH corresponding to a specific BWP to obtain a preemption indicator, and based on the obtained preemption indicator, determine whether a data channel or a control channel transmitted from the corresponding BWP has been affected by preemption. If the terminal does not need to confirm whether a data channel or a control channel transmitted from a specific BWP has been affected by preemption, the terminal does not need to blindly decode the group common PDCCH for obtaining the preemption indicator in the CORESET corresponding to the corresponding BWP. In such an embodiment, the terminal can prevent waste of power generated by blind decoding.

[0109] In the embodiment of FIG. 15(a), the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2) are set so as not to overlap with each other. In the embodiment of FIG. 15(b), the second BWP (Bandwidth part #2) includes the entire frequency band indicated by the first BWP (Bandwidth part #1). In the embodiments of FIGS. 15(a) and 15(b), the base station transmits a group common PDCCH including a preemption indicator that signals information regarding the preemption operation performed in the first BWP (BW part #1) in the first CORESET (CORESET #1) corresponding to the first BWP (BW part #1). The terminal assumes that a group common PDCCH or a UE-specific PDCCH including a preemption indicator that signals information regarding the preemption operation performed in the first BWP (BW part #1) is transmitted in the first CORESET (CORESET #1) corresponding to the first BWP (BW part #1). The terminal monitors the group common PDCCH or the UE-specific PDCCH in the first CORESET (CORESET #1) in order to obtain a preemption indicator that signals information regarding the preemption operation performed in the first BWP (BW part #1). Further, the base station transmits a group common PDCCH or a UE-specific PDCCH including a preemption indicator that signals information regarding the preemption operation performed in the second BWP (BW part #2) in the second CORESET (CORESET #2) corresponding to the second BWP (BW part #2). The terminal assumes that a group common PDCCH or a UE-specific PDCCH including a preemption indicator that signals information regarding the preemption operation performed in the second BWP (BW part #2) is transmitted in the second CORESET (CORESET #2) corresponding to the second BWP (BW part #2).The terminal monitors the group common PDCCH or the terminal-specific PDCCH in the second CORESET (CORESET #2) to obtain a preemption indicator that signals information regarding the preemption operation performed in the second BWP (BW part #2).

[0110] In the embodiment of FIG. 15, it was described that the base station transmits the preemption indicator in the next slot in which preemption occurred. However, the timing at which the base station transmits the preemption indicator is not limited to the next slot in which preemption occurred. Specifically, if preemption occurs in the nth slot (Slot #n), the base station transmits the preemption indicator in the nth slot (Slot #n), which is the same slot, after preemption has occurred. Also, if preemption occurs in the nth slot (Slot #n), the base station may transmit the preemption indicator in the (n + 1)th slot (Slot #n + 1) after preemption has occurred. If preemption occurs in the nth slot (Slot #n), the base station may transmit the preemption indicator in the (n + k)th slot (Slot #n + k) after preemption has occurred. At this time, k is a natural number of 1 or more. The explanation regarding the timing at which the base station transmits the preemption indicator is also applied to other embodiments described later, unless otherwise specifically mentioned.

[0111] FIG. 16 is a diagram showing a method by which a terminal according to an embodiment of the present invention monitors a preemption indicator based on a CORESET corresponding to a BWP in which PDSCH is scheduled. The base station transmits a control channel including a preemption indicator that signals information regarding preemption occurring in the corresponding BWP in a CORESET corresponding to the BWP in which the data channel is scheduled. If a plurality of BWPs are set in the terminal so as not to overlap with each other, the terminal assumes that a control channel including a preemption indicator that signals information regarding preemption occurring in the BWP in which the data channel is scheduled is transmitted from the CORESET corresponding to the BWP. Therefore, if a plurality of BWPs are set in the terminal so as not to overlap with each other, the terminal monitors the control channel in the CORESET corresponding to the BWP in order to obtain a preemption indicator that signals information regarding preemption occurring in the BWP in which the data channel is scheduled. Further, if a plurality of BWPs are set in the terminal so as not to overlap with each other, the terminal does not have to monitor the control channel in a CORESET other than the CORESET corresponding to the BWP in order to obtain a preemption indicator that signals information regarding preemption occurring in the BWP in which the data channel is scheduled. In such an embodiment, the control channel is a group common PDCCH or a UE-specific PDCCH. Further, the data channel is a PDSCH.

[0112] In the embodiment of FIG. 16, a first BWP (Bandwidth part #1) and a second BWP (Bandwidth part #2) are set for the terminal, and the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2) do not overlap with each other. In the embodiment of FIG. 16(a), the PDSCH is scheduled only on the first BWP (Bandwidth part #1) among the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). At this time, it is assumed that a group common PDCCH or a terminal-specific PDCCH including a preemption indicator is transmitted only on the first CORESET (CORESET #1) corresponding to the first BWP (Bandwidth part #1). Therefore, the terminal monitors the group common PDCCH or the terminal-specific PDCCH on the first CORESET (CORESET #1) in order to obtain a preemption indicator that signals information regarding the preemption operation performed on the first BWP (Bandwidth part #1). Also, it is assumed that a group common PDCCH or a terminal-specific PDCCH including a preemption indicator that signals information regarding the preemption operation performed on the first BWP (BW part #1) is transmitted in the second CORESET (CORESET #2) where the PDSCH is not scheduled. Therefore, even if the terminal is set to monitor the second CORESET (CORESET #2), the terminal does not have to monitor the group-common PDCCH or the terminal-specific PDCCH in order to obtain a preemption indicator that signals information regarding the preemption operation performed on the first BWP (BW part #1) in the second CORESET (CORESET #2).

[0113] In the embodiment of FIG. 16(b), PDSCH is scheduled only on the second BWP (Bandwidth part #2) out of the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). At this time, it is assumed that a group-common PDCCH or a UE-specific PDCCH including a preemption indicator is transmitted only on the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2). Therefore, the UE monitors the group-common PDCCH or the UE-specific PDCCH on the second CORESET (CORESET #2) in order to acquire a preemption indicator that signals information regarding the preemption operation performed on the second BWP (Bandwidth part #2). Also, the UE assumes that a group-common PDCCH or a UE-specific PDCCH including a preemption indicator that signals information regarding the preemption operation performed on the second BWP (BW part #2) is transmitted in the first CORESET (CORESET #1) on which PDSCH is not scheduled. Therefore, even if the UE is configured to monitor the first CORESET (CORESET #1), the UE does not have to monitor the group-common PDCCH or the UE-specific PDCCH in order to acquire a preemption indicator that signals information regarding the preemption operation performed on the second BWP (BW part #2) in the first CORESET (CORESET #1).

[0114] In the embodiment of FIG. 16(c), the PDSCH is scheduled by the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2), respectively. At this time, it is assumed that the group-common PDCCH or the UE-specific PDCCH including the preemption indicator is transmitted only in the first CORESET (CORESET #1) corresponding to the first BWP (Bandwidth part #1). Therefore, in order for the UE to obtain the preemption indicator that signals information about the preemption operation performed in the first BWP (Bandwidth part #1), the UE monitors the group-common PDCCH or the UE-specific PDCCH in the first CORESET (CORESET #1). Also, it is assumed that the group-common PDCCH or the UE-specific PDCCH including the preemption indicator is transmitted only in the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2). Therefore, in order for the UE to obtain the preemption indicator that signals information about the preemption operation performed in the second BWP (Bandwidth part #2), the UE monitors the group-common PDCCH or the UE-specific PDCCH in the second CORESET (CORESET #2).

[0115] If a plurality of BWPs are set to overlap in the UE, the UE may have difficulty determining which BWP the BWP for which the PDSCH is scheduled is. Therefore, if a plurality of BWPs are set to overlap in the UE, a method for the UE to determine the CORESET to be monitored in order to obtain the preemption indicator is required. This will be described with reference to FIG. 17.

[0116] FIG. 17 is a diagram showing a method of monitoring a preemption indicator based on the CORESET corresponding to the BWP for which the PDSCH is scheduled if a plurality of BWPs set in the UE according to an embodiment of the present invention overlap.

[0117] If multiple BWPs configured at the terminal overlap, the base station transmits a control channel including a preemption indicator that signals information regarding preemption occurring in the transmission of the corresponding data channel, using a CORESET corresponding to the smallest BWP among the BWPs that include all the frequency regions in which the data channel is scheduled. If multiple BWPs configured at the terminal overlap, the terminal assumes that a control channel including a preemption indicator that signals information regarding preemption occurring in the transmission of the corresponding data channel is transmitted from a CORESET corresponding to the smallest BWP among the BWPs that include all the frequency regions in which the data channel is scheduled. Therefore, if multiple BWPs configured at the terminal overlap, the terminal monitors the control channel using a CORESET corresponding to the smallest BWP among the BWPs that include all the frequency regions in which the data channel is scheduled, in order to obtain a preemption indicator that signals information regarding preemption occurring in the transmission of the corresponding data channel. Also, if multiple BWPs configured at the terminal overlap, the terminal does not necessarily need to monitor the control channel using a CORESET other than the CORESET corresponding to the smallest BWP among the BWPs that include all the frequency regions in which the data channel is scheduled, in order to obtain a preemption indicator that signals information regarding preemption occurring in the transmission of the corresponding data channel. In such an embodiment, the control channel is a group common PDCCH or a UE-specific PDCCH. Also, in such an embodiment, the data channel is a PDSCH.

[0118] In the embodiment of FIG. 17, a first BWP (Bandwidth part #1) and a second BWP (Bandwidth part #2) are set for the terminal. Also, the second BWP (Bandwidth #2) includes the first BWP (Bandwidth part #1). For convenience of explanation, regarding the embodiment of FIG. 17, a preemption indicator that signals information regarding preemption for PDSCH transmission is referred to as a preemption indicator. In the embodiment of FIG. 17(a), PDSCH is scheduled in a frequency region that includes both the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). Since the first BWP (Bandwidth part #1) is the smallest among the BWPs that include all the frequency regions where PDSCH is scheduled, it is assumed that a group-common PDCCH or a UE-specific PDCCH including a preemption indicator is transmitted only on the first CORESET (CORESET #1) corresponding to the first BWP (Bandwidth part #1). Therefore, the terminal monitors the group-common PDCCH or the UE-specific PDCCH on the first CORESET (CORESET #1) to obtain the preemption indicator. Also, it is assumed that a group-common PDCCH or a UE-specific PDCCH including a preemption indicator is not transmitted in the second CORESET (CORESET #2) where PDSCH is not scheduled. Therefore, even if the terminal is set to monitor the second CORESET (CORESET #2), the terminal does not have to monitor the group-common PDCCH or the UE-specific PDCCH to obtain the preemption indicator on the second CORESET (CORESET #2).

[0119] In the embodiment of FIG. 17(b), the PDSCH is scheduled in the frequency region included only in the second BWP (Bandwidth part #2) among the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). Since the second BWP (Bandwidth part #2) is the smallest among the BWPs including all the frequency regions where the PDSCH is scheduled, it is assumed that the group common PDCCH or the UE-specific PDCCH including the preemption indicator is transmitted only by the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2). Therefore, the UE monitors the group common PDCCH or the UE-specific PDCCH by the second CORESET (CORESET #2) in order to acquire the preemption indicator. Also, it is assumed that the group common PDCCH or the UE-specific PDCCH including the preemption indicator is not transmitted in the first CORESET (CORESET #1) where the PDSCH is not scheduled. Therefore, even if the UE is set to monitor the first CORESET (CORESET #1), the UE does not have to monitor the group common PDCCH or the UE-specific PDCCH in order to acquire the preemption indicator by the first CORESET (CORESET #1).

[0120] In the embodiment of FIG. 17(c), the first BWP (Bandwidth part #1) includes a part of the frequency region where PDSCH is scheduled, and the second BWP (Bandwidth part #2) includes all of the frequency region where PDSCH is scheduled. Since the first BWP (Bandwidth part #1) does not include all of the frequency region where PDSCH is scheduled and the second BWP (Bandwidth part #2) includes all of the frequency region where PDSCH is scheduled, it is assumed that the group common PDCCH or the UE-specific PDCCH including the preemption indicator is transmitted only on the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2). Therefore, the UE monitors the group common PDCCH or the UE-specific PDCCH on the second CORESET (CORESET #2) to acquire the preemption indicator. Also, it is assumed that the group common PDCCH or the UE-specific PDCCH including the preemption indicator is not transmitted in the first CORESET (CORESET #1) where PDSCH is not scheduled. Therefore, even if the UE is set to monitor the first CORESET (CORESET #1), the UE does not have to monitor the group common PDCCH or the UE-specific PDCCH to acquire the preemption indicator in the first CORESET (CORESET #1).

[0121] The base station transmits the preemption indicator using the UE-specific PDCCH or the group common PDCCH. At this time, regardless of the BWP where PDSCH is scheduled, the base station transmits the UE-specific PDCCH or the group common PDCCH including the preemption indicator via a pre-specified BWP. This will be described with reference to FIGS. 18 to 19. FIGS. 18 and 19 are diagrams showing a method by which a UE monitors a preemption indicator based on a pre-specified BWP according to an embodiment of the present invention.

[0122] As described above, regardless of the BWP for which the PDSCH is scheduled, the base station transmits a specific terminal PDCCH or a group common PDCCH including a preemption indicator via a pre-specified BWP. Therefore, it is assumed that the terminal receives a specific terminal PDCCH or a group common PDCCH including a preemption indicator via the pre-specified BWP. The terminal monitors a specific terminal PDCCH or a group common PDCCH including a preemption indicator in the pre-specified BWP in order to acquire the preemption indicator.

[0123] In the embodiment of FIG. 18, a first BWP (Bandwidth part #1) and a second BWP (Bandwidth part #2) are set for the terminal, and the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2) do not overlap with each other. In the embodiment of FIG. 18(a), the PDSCH is scheduled only for the first BWP (Bandwidth part #1) out of the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). In the embodiment of FIG. 18(b), the PDSCH is scheduled only for the second BWP (Bandwidth part #2) out of the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). In the embodiment of FIG. 18(c), the PDSCH is scheduled for each of the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2).

[0124] In the embodiment of FIG. 19, a first BWP (Bandwidth part #1) and a second BWP (Bandwidth part #2) are configured for the terminal. Also, the second BWP (Bandwidth #2) includes the first BWP (Bandwidth part #1). In the embodiment of FIG. 19(a), the PDSCH is scheduled in the frequency region including both the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). In the embodiment of FIG. 19(b), the PDSCH is scheduled in the frequency region including only the second BWP (Bandwidth part #2) among the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). In the embodiment of FIG. 19(c), the first BWP (Bandwidth part #1) includes a part of the frequency region in which the PDSCH is scheduled, and the second BWP (Bandwidth part #2) includes all of the frequency region in which the PDSCH is scheduled.

[0125] For convenience of explanation, regarding the embodiments of FIGS. 18 to 19, a preemption indicator for signaling information regarding preemption for PDSCH transmission is referred to as a preemption indicator. In the embodiments of FIGS. 18 to 19, the base station transmits a specific terminal PDSCH or a group common PDCCH including a preemption indicator only in a first CORESET (CORESET #1) corresponding to a pre-specified first BWP (Bandwidth part #1). Therefore, it is assumed that the terminal-specific PDCCH or the group common PDCCH including a preemption indicator is transmitted only in the first CORESET (CORESET #1) corresponding to the pre-specified first BWP (Bandwidth part #1). The terminal monitors the terminal-specific PDCCH or the group common PDCCH in the first CORESET (CORESET #1) to obtain the preemption indicator. Also, the terminal does not need to monitor the terminal-specific PDCCH or the group common PDCCH in the second CORESET (CORESET #2) to obtain the preemption indicator.

[0126] The DCI payload of the specific terminal PDCCH or the group common PDCCH includes a preemption indicator. At this time, the length of the DCI payload of the specific terminal PDCCH or the group common PDCCH is variable. Therefore, the terminal determines the length of the DCI payload of the specific terminal PDCCH or the group common PDCCH, and blindly decodes the specific terminal PDCCH or the group common PDCCH based on the determined length of the DCI payload of the specific terminal PDCCH or the group common PDCCH.

[0127] In a specific embodiment, the length of the DCI payload of the specific terminal PDCCH or the group common PDCCH including the preemption indicator may vary depending on the number of BWPs in which the PDSCH is transmitted. For example, the length of the DCI payload of the PDCCH when the frequency region in which the PDSCH is transmitted is included in n BWPs may be longer than the length of the DCI payload of the PDCCH when it is included in k BWPs. At this time, both n and k are natural numbers, and n is greater than k. Specifically, the length of the DCI payload of the PDCCH when the frequency region in which the PDSCH is transmitted is included in two BWPs may be longer than the length of the DCI payload of the PDCCH when it is included in one BWP. The base station sets the length of the DCI payload of the PDCCH including the preemption indicator based on the number of BWPs in which the PDSCH is transmitted according to such an embodiment. Also, the terminal determines the length of the DCI payload of the PDCCH including the preemption indicator based on the number of BWPs in which the PDSCH is transmitted according to such an embodiment.

[0128] In other specific embodiments, the length of the DCI payload of the specific terminal PDCCH or the group common PDCCH including the preemption indicator may vary depending on the number of PRBs occupied by the PDSCH. Specifically, if the number of PRBs occupied by the PDSCH is X, the length of the DCI payload of the PDCCH increases or decreases in proportion to X. Specifically, the length of the DCI payload of the PDCCH including the preemption indicator is ceil(k*X) bits. At this time, k is a number between 0 and 1, and ceil(a) is the smallest natural number that is the same as or greater than a. In this specification, unless specifically mentioned otherwise, ceil(a) indicates the smallest natural number that is the same as or greater than a. The base station sets the length of the DCI payload of the PDCCH including the preemption indicator based on the number of PRBs occupied by the PDSCH according to such an embodiment. Also, the terminal determines the length of the DCI payload of the PDCCH including the preemption indicator based on the number of PRBs occupied by the PDSCH according to such an embodiment.

[0129] In other specific embodiments of the present invention, the base station transmits a control channel including a preemption indicator based on the CORESET on which the control channel for scheduling the data channel is transmitted. This will be described in detail with reference to FIG. 20.

[0130] FIG. 20 is a diagram showing a method for a terminal according to an embodiment of the present invention to monitor a preemption indicator in a CORESET on which a PDCCH for scheduling a PDSCH is transmitted.

[0131] In a specific embodiment, the base station transmits a control channel including a preemption indicator for signaling information regarding preemption occurring in the transmission of a corresponding data channel, where the frequency region in which the data channel is scheduled is a CORESET in which a control channel for scheduling the data channel is transmitted. The terminal assumes that a control channel including a preemption indicator for signaling information regarding preemption occurring from the transmission of the data channel is transmitted from a CORESET in which the control channel for scheduling the data channel is transmitted in the frequency region in which the data channel is scheduled. Therefore, in order for the terminal to obtain a preemption indicator for signaling information regarding preemption occurring from the transmission of the corresponding data channel, the terminal monitors the control channel in the CORESET in which the control channel for scheduling the data channel is transmitted in the frequency region in which the data channel is scheduled. Also, in order for the terminal to obtain a preemption indicator for signaling information regarding preemption occurring from the transmission of the corresponding data channel, the terminal does not have to monitor the control channel in a CORESET other than the CORESET in which the control channel for scheduling the data channel is transmitted in the frequency region in which the data channel is scheduled. In such an embodiment, the control channel is a group common PDCCH or a terminal specific PDCCH. Also, in such an embodiment, the data channel is a PDSCH.

[0132] In the embodiment of FIG. 20, a first BWP (Bandwidth part #1) and a second BWP (Bandwidth part #2) are set in the terminal. Also, the second BWP (Bandwidth #2) includes the first BWP (Bandwidth part #1). In the embodiment of FIG. 20(a), the PDSCH is scheduled in the frequency region including both the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). In the embodiment of FIG. 20(b), the PDSCH is scheduled in the frequency region including only the second BWP (Bandwidth part #2) among the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). In the embodiment of FIG. 20(c), the first BWP (Bandwidth part #1) includes a part of the frequency region in which the PDSCH is scheduled, and the second BWP (Bandwidth part #2) includes all of the frequency region in which the PDSCH is scheduled.

[0133] For the sake of convenience of explanation, regarding the embodiment of FIG. 20, a preemption indicator that signals information regarding preemption for PDSCH transmission is referred to as a preemption indicator. In the embodiments of FIGS. 20(a) to 20(b), all PDCCHs that schedule PDSCH are transmitted from the first CORESET (CORESET #1). Therefore, the base station transmits a UE-specific PDCCH or a group-common PDCCH including a preemption indicator only in the first CORESET (CORESET #1) corresponding to the pre-specified first BWP (Bandwidth part #1). Therefore, it is assumed that the UE-specific PDCCH or the group-common PDCCH including the preemption indicator is transmitted only in the first CORESET (CORESET #1) corresponding to the pre-specified first BWP (Bandwidth part #1). The UE monitors the UE-specific PDCCH or the group-common PDCCH in the first CORESET (CORESET #1) to acquire the preemption indicator. Also, the UE does not necessarily need to monitor the UE-specific PDCCH or the group-common PDCCH in the second CORESET (CORESET #2) to acquire the preemption indicator.

[0134] Through FIGS. 21 to 30, the preemption indication method of the preemption indicator will be described in detail. To explain the OFDM symbol for which the preemption indicator indicates the occurrence or non-occurrence of preemption, first, the OFDM symbol configuration included in the slot will be described.

[0135] FIG. 21 is a diagram showing an example of setting the OFDM symbols included in a slot if TDD is used in a wireless communication system according to an embodiment of the present invention. In the wireless communication system according to the embodiment of the present invention, if TDD is used, the symbols included in a slot are classified into DL symbols, UL symbols, and flexible symbols. A DL symbol is a symbol for scheduling DL transmission. Also, a UL symbol is a symbol for scheduling UL transmission. A flexible symbol is a symbol that does not fall into DL symbols and UL symbols. A flexible symbol is referred to as an Unknown symbol. Also, a flexible symbol is used for a time gap required for switching between DL transmission and UL transmission. A slot has various symbol configurations. FIG. 21 shows an example of the symbol configuration included in a certain slot. In the embodiment of FIG. 21, one slot includes 14 symbols. Also, in the drawing, N DL indicates the number of DL symbols, and N FL indicates the number of flexible symbols, and N UL indicates the number of UL symbols. In the embodiment of FIG. 21, any one slot includes 7 DL symbols, 3 flexible symbols, and 4 UL symbols.

[0136] The base station uses RRC configuration to signal the slot format to the terminal. At this time, the base station uses at least one of the cell-specific RRC signal and the specific-terminal RRC signal. Specifically, the base station uses RRC configuration to signal which symbol among the symbols of each slot corresponds to either a DL symbol, a UL symbol, or a flexible symbol. Specifically, the base station uses RRC configuration to signal the symbols that explicitly correspond to DL symbols and the symbols that correspond to UL symbols among the multiple OFDM symbols included in the slot. In a specific embodiment, the terminal determines that the symbols indicated as DL slots and DL symbols by the cell-specific RRC signal are DL symbols, determines that the symbols indicated as UL slots and UL symbols by the cell-specific RRC signal are UL symbols, and determines that the symbols indicated as flexible symbols by the cell-specific RRC signal are flexible symbols. Alternatively, the terminal determines that the symbols not indicated as DL slots and DL symbols and not indicated as UL slots and UL symbols by the cell-specific RRC signal are flexible symbols.

[0137] In addition, the base station signals in a table-of-contents manner that, among the multiple OFDM symbols included in a slot, the symbols other than the symbols corresponding to DL symbols and the symbols corresponding to UL symbols correspond to flexible symbols. Therefore, based on the RRC configuration, the terminal determines which one of the DL symbol, UL symbol, and flexible symbol the symbol included in the slot is. Specifically, the terminal determines the symbol indicated as the DL symbol by the RRC configuration as the DL symbol, and determines the symbol indicated as the UL symbol by the RRC configuration as the UL symbol. Also, the terminal determines a symbol that is not indicated as a DL symbol or a UL symbol by the RRC configuration as a flexible symbol. In a specific embodiment, the terminal determines the symbol indicated as the DL symbol by the cell-specific RRC signal as the DL symbol, determines the symbol indicated as the UL symbol by the cell-specific RRC signal as the UL symbol, and determines a symbol that is not indicated as a DL symbol or a UL symbol by the cell-specific RRC signal as a flexible symbol. At this time, the base station sets the flexible symbol using the per-terminal RRC signal. Therefore, based on the per-terminal RRC signal, the terminal determines whether the OFDM symbol indicated as the flexible symbol by the cell-specific RRC signal is a DL symbol, a UL symbol, or a flexible symbol. Specifically, if the per-terminal RRC signal indicates the OFDM symbol indicated as the flexible symbol by the cell-specific RRC signal as the DL symbol, the terminal determines the corresponding OFDM symbol as the DL symbol. Also, if the per-terminal RRC signal indicates the OFDM symbol indicated as the flexible symbol by the cell-specific RRC signal as the UL symbol, the terminal determines the corresponding OFDM symbol as the UL symbol. Also, if the per-terminal RRC signal does not indicate the OFDM symbol indicated as the flexible symbol by the cell-specific RRC signal as a UL symbol or a DL symbol, the terminal determines the corresponding OFDM symbol as a flexible symbol. In another specific embodiment, if the per-terminal RRC signal indicates the OFDM symbol indicated as the flexible symbol by the cell-specific RRC signal as the flexible symbol, the terminal determines the corresponding OFDM symbol as the flexible symbol.

[0138] The terminal always assumes that the symbol configured as a DL symbol by RRC configuration is a DL symbol. Also, the terminal always assumes that the symbol configured as a UL symbol by RRC configuration is a UL symbol. As described above, the flexible symbol is referred to as an unknown symbol. This is because the base station can additionally indicate the information that the flexible symbol is used via additional signaling. Specifically, the base station indicates (indicates) the flexible symbol as a DL symbol or a UL symbol via additional signaling other than RRC configuration. The additional signaling other than RRC configuration includes at least one of control information, a control signal, and a control channel. The control channel includes PDCCH. At this time, the PDCCH includes a group common PDCCH that indicates information to a plurality of terminals. Also, the PDCCH includes a specific terminal PDCCH that indicates information to any one terminal. The control channel includes DCI. For example, the additional signaling other than RRC may be a UE-specific DCI that includes PDSCH or PUSCH scheduling information. Also, the additional signaling other than RRC is a dynamic SFI of the L1-signal that indicates information regarding slot configuration. At this time, the dynamic SFI is transmitted via the group common PDCCH, and the dynamic SFI uses a DCI format having a CRC scrambled by the SFI-RNTI.

[0139] Also, in additional signaling other than RRC configuration, if the flexible symbol is not indicated as a DL symbol or a UL symbol, the terminal does not assume transmission to the base station or reception from the base station using the flexible symbol. In additional signaling other than RRC configuration, if the flexible symbol is indicated as a DL symbol or a UL symbol, the terminal assumes the flexible symbol as a DL symbol or a UL symbol as indicated by the additional signaling. Therefore, if the additional signaling indicates that the flexible symbol is a DL symbol, the terminal assumes reception from the base station using the corresponding symbol. Also, if the additional signaling indicates that the flexible symbol is a UL symbol, the terminal performs transmission to the base station using the corresponding symbol.

[0140] Also, in this specification, unless otherwise explicitly stated, the RRC signal for slot configuration indicates the cell-specific RRC signal in system information. The base station indicates that the name of the cell-specific RRC signal is Slot-assignmnetSIB1. Also, the name of the specific terminal RRC signal is Slot-assignmnet. FIG. 22 is a diagram showing the OFDM symbol indicated by the preemption indicator according to an embodiment of the present invention.

[0141] The preemption indicator indicates information regarding preemption of a plurality of OFDM symbols. For convenience of explanation, the OFDM symbol indicated by the preemption indicator is referred to as a reference DL resource. Also, the base station transmits a control channel including a preemption indicator for each one or more slots. The terminal monitors a control channel including a preemption indicator for each one or more slots. At this time, the terminal determines the period of the CORESET for monitoring the preemption indicator based on the RRC signal. The duration of the reference DL resource is determined by the period in which the base station transmits a control channel including a preemption indicator. Also, the duration of the reference DL resource is determined by the period in which the terminal monitors a control channel including a preemption indicator.

[0142] If the terminal monitors a control channel including a preemption indicator for every x slots, the preemption indicator obtained by the terminal from the control channel transmitted from the n-th slot indicates information about the preemption that occurred from the (n - x)-th slot, the (n - x + 1)-th slot, …, the (n - 1)-th slot. Therefore, if the terminal obtains a preemption indicator from the control channel transmitted from the n-th slot, the terminal determines the preemption that occurred from the (n - x)-th slot, the (n - x + 1)-th slot, …, the (n - 1)-th slot based on the obtained preemption indicator. The time interval corresponding to the reference DL resource is from the next symbol of the CORESET in which the control channel including the preemption indicator immediately before the corresponding preemption indicator is received to the last symbol of the CORESET in which the control channel including the corresponding preemption indicator is received. Alternatively, the time interval corresponding to the reference DL resource indicates from the start symbol of the CORESET set to monitor the control channel including the preemption indicator immediately before the received preemption indicator to before the first symbol of the CORESET in which the control channel including the corresponding preemption indicator is received.

[0143] The frequency band corresponding to the reference DL resource is the entire frequency band of the BWP in which the preemption indicator indicating the preemption generated from the corresponding reference DL resource is transmitted. In other specific embodiments, the frequency band corresponding to the reference DL resource is a specific frequency band indicated by the RRC configuration of the base station. At this time, the specific frequency band is a continuous frequency band. In a specific embodiment, the specific frequency band is a discontinuous frequency band.

[0144] Also, the preemption indicator indicates resources pre-empted (or punctured) in the time domain and the frequency domain. At this time, the preemption indicator includes information indicating resources pre-empted (or punctured) in the frequency domain.

[0145] In the embodiment of FIG. 22, the base station receives a control channel including a preemption indicator every four slots. Also, the terminal monitors a control channel including a preemption indicator every four slots. Therefore, if the control channel including the preemption indicator is transmitted from the nth slot, the corresponding preemption indicator indicates which DL resource among the DL resources included in the reference DL resource has preemption occurred from the (n - 4)th slot to the (n - 1)th slot.

[0146] The dedicated preemption indicator includes information regarding which resource among the DL resources allocated to a specific terminal has been preempted. Therefore, the preemption indicator includes information necessary for the terminal to which the DL resource is allocated. Also, the terminal to which the UL resource is allocated needs to monitor the preemption indicator. The preemption indicator indicates information regarding the remaining OFDM symbols excluding some of the OFDM symbols included in the slot corresponding to the preemption indicator. This will be described with reference to FIGS. 23 to 26.

[0147] FIG. 23 is a diagram showing the OFDM symbols indicated by the preemption indicator according to an embodiment of the present invention. Some symbols are determined by the RRC signal indicating the use of the corresponding symbol. Specifically, the preemption indicator indicates only information regarding resources corresponding to DL symbols or flexible symbols that can become DL symbols. In such an embodiment, the reference DL resources are discontinuous. The terminal then determines the OFDM symbols for which the preemption indicator indicates information regarding preemption according to the following embodiment.

[0148] In a specific embodiment, the base station explicitly indicates a reference DL resource corresponding to a preemption indicator using an RRC configuration. The terminal assumes that preemption is performed only in the OFDM symbols indicated by the RRC configuration in the DL slot and DL symbol. Further, the terminal assumes that the preemption indicator indicates information regarding preemption generated from the OFDM symbol indicated by the reference DL resource corresponding to the preemption indicator. For example, the base station transmits a bitmap indicating the OFDM symbol corresponding to the reference DL resource to the terminal using an RRC signal. At this time, each bit of the bitmap indicates whether the OFDM symbol corresponding to each bit is a preemption indicator. In the embodiment of FIG. 23, the base station transmits a control channel including a preemption indicator every four slots. At this time, each slot includes 14 OFDM symbols. The base station transmits a bitmap having a length of 56 bits using an RRC signal to indicate the OFDM symbol corresponding to the reference DL resource. The terminal acquires the bitmap from the RRC signal and determines the OFDM symbol corresponding to the reference DL resource.

[0149] In other specific embodiments, the terminal determines the OFDM symbols corresponding to the reference DL resources based on the slot format set in the RRC signal. Specifically, the terminal determines that the OFDM symbols set as UL symbols by the RRC configuration are not included in the reference DL resources. This is because the terminal always assumes that the OFDM symbols set as UL symbols by the RRC configuration are UL symbols. The terminal assumes that the base station does not preempt the OFDM symbols set as UL symbols by the RRC configuration. In a specific embodiment, the terminal determines that the reference DL resources include only the new symbols indicated as DL symbols or flexible symbols in the RRC configuration. Specifically, the base station sets the remaining OFDM symbols among the OFDM symbols within the preemption indicator transmission period, excluding the OFDM symbols set as UL symbols by the RRC signal, as the reference DL resources. At this time, the base station sets the preemption indicator based on the information regarding the preemption for the corresponding reference DL resources, and signals the preemption indicator to the terminal via the control channel. Also, the terminal determines that the OFDM symbols set as UL symbols by the RRC signal are not included in the reference DL resources. The terminal determines the OFDM symbols set as DL symbols by the RRC signal and the symbols set as flexible symbols by the RRC signal among the OFDM symbols during the preemption indicator monitoring period as the reference DL resources. For example, it may be assumed that the OFDM symbols during the preemption indicator monitoring period are set as A DL symbols set by the RRC signal, C flexible symbols set by the RRC signal, and B UL symbols set by the RRC signal. At this time, the terminal determines the A DL symbols set by the RRC signal and the C flexible symbols set by the cell-specific signal as the reference DL resources.

[0150] In such an embodiment, the RRC signal includes a cell-specific RRC signal and does not include a specific-terminal RRC signal. Specifically, the base station sets the remaining OFDM symbols except for the OFDM symbols set as UL symbols by the cell-specific RRC signal among the OFDM symbols within the preemption indicator transmission period as reference DL resources, and sets a preemption indicator based on information regarding preemption for the corresponding reference DL resources. At this time, the base station signals the preemption indicator to the terminal via a control channel. Also, the terminal determines that the OFDM symbols set as UL symbols by the cell-specific RRC signal are not included in the reference DL resources. The terminal determines the OFDM symbols set as DL symbols by the cell-specific RRC signal and the symbols set as flexible symbols by the cell-specific RRC signal among the OFDM symbols during the preemption indicator monitoring period as reference DL resources. For example, it may be assumed that the OFDM symbols during the preemption indicator monitoring period are set as A DL symbols set by the cell-specific RRC signal, C flexible symbols set by the cell-specific RRC signal, and B UL symbols set by the cell-specific RRC signal. At this time, the terminal determines the A DL symbols set by the cell-specific RRC signal and the C flexible symbols set by the cell-specific signal as reference DL resources.

[0151] In such an embodiment, the RRC signal may include not only the cell-specific RRC signal but also the specific-terminal RRC signal. Thus, the terminal determines that the OFDM symbol set as the UL symbol by the cell-specific RRC signal and the OFDM symbol set as the UL symbol by the specific-terminal RRC signal are not included in the reference DL resource. The terminal determines that, among the OFDM symbols during the preemption indicator monitoring period, the remaining symbols excluding the OFDM symbol set as the DL symbol by the cell-specific RRC signal and the OFDM symbol set as the DL symbol by the specific-terminal RRC signal are the reference DL resource. If the terminal does not receive the specific-terminal RRC signal or the corresponding specific-terminal RRC signal is not configured for the terminal, the terminal determines the reference DL resource based only on the cell-specific RRC signal.

[0152] Also, the terminal excludes n flexible symbols that are continuously located before the UL symbol in the reference DL resource. Specifically, the base station takes the OFDM symbol set as the UL symbol by the RRC signal among the OFDM symbols within the preemption indicator transmission period, and excludes the n flexible symbols that are continuously located immediately before the OFDM symbol set as the UL symbol by the RRC signal, and sets the remaining OFDM symbols as the reference DL resource, and sets the preemption indicator based on the information regarding preemption for the corresponding reference DL resource. At this time, the base station signals the preemption indicator to the terminal via the control channel. This is because a time interval (gap) for base change between DL transmission and UL transmission is required, and thus there may be flexible symbols that cannot be used for UL transmission or DL transmission. Specifically, the n flexible symbols that are continuously located immediately before the UL symbol correspond to the guard period for DL-UL switching, and although they may potentially be assigned to the UL symbol, they cannot potentially be assigned to the DL symbol. Also, the terminal determines that the OFDM symbol set as the UL symbol by the RRC signal and the n flexible symbols that are continuously located immediately before the OFDM symbol set as the UL symbol by the RRC signal are not included in the reference DL resource. The terminal determines as the reference DL resource the OFDM symbols within the preemption indicator monitoring period, excluding the n symbols that are set as flexible symbols by the RRC signal and are continuously located immediately before the UL symbol, from among the OFDM symbols set as DL symbols by the RRC signal and the flexible symbols. At this time, n is 1. Also, n is 2 or more. Also, the base station signals the value of n using the RRC signal. At this time, the terminal determines the value of n using the RRC signal. Also, in the "OFDM symbol set as the UL symbol by the RRC signal among the OFDM symbols within the preemption indicator transmission period", the RRC signal includes the cell-specific RRC signal and does not include the specific terminal RRC signal.In a specific embodiment of the present invention, in the "OFDM symbol set as a UL symbol by an RRC signal among the OFDM symbols within a preemption indicator transmission period", the RRC signal includes both a cell-specific RRC signal and a specific-terminal RRC signal.

[0153] The NR system reserves some resources for forward compatibility or back compatibility. Such resources are referred to as reserved resources. The reserved resources are used for DL transmission or UL transmission. Therefore, the reference DL resources are set in consideration of the reserved resources. This will be described with reference to FIGS. 24 to 26.

[0154] FIGS. 24 to 26 are diagrams showing OFDM symbols indicated by a preemption indicator according to an embodiment of the present invention with respect to reserved resources. In the above-described embodiment, the terminal excludes symbols mapped from the reference DL resources to the reserved resources. Specifically, the terminal excludes from the reference DL resources an OFDM symbol in which all PRBs of the OFDM symbol are set as reserved resources.

[0155] In FIG. 24, some PRBs of some symbols among the OFDM symbols within a preemption indicator transmission period are set as reserved resources. Therefore, the terminal determines that the reference DL resources include the corresponding symbol. In FIG. 25, all PRBs of some symbols among the OFDM symbols within a preemption indicator transmission period are set as reserved resources. Therefore, the terminal determines that the reference DL resources do not include the corresponding symbol.

[0156] In other specific embodiments, the terminal excludes symbols mapped from the reference DL resource to the reserved resource based on the frequency domain where the reserved resource is mapped. Specifically, according to the frequency domain granularity used for the preamble indicator, the reference DL resource is divided from the frequency domain. If the reference DL resource is divided from the frequency domain, the terminal excludes all PRBs set as reserved resources from the reference DL resource for each divided frequency domain.

[0157] In FIG. 26, the frequency domain granularity is half of the PRBs occupied by the reference DL resource. Thus, the reference DL resource is divided into two regions along the dotted line. When the preamble indicator corresponds to the reference DL resource above the dotted line among the OFDM symbols in the transmission period, there is an OFDM symbol in which all PRBs are set as reserved resources. Therefore, the terminal excludes the corresponding symbol from the reference DL resource. When the preamble indicator corresponds to the reference DL resource below the dotted line among the OFDM symbols in the transmission period, there is no OFDM symbol in which all PRBs are set as reserved resources. However, when the preamble indicator corresponds to the reference DL resource below the dotted line among the OFDM symbols in the transmission period, there is an OFDM symbol in which all PRBs are set as reserved resources. Therefore, the terminal does not exclude the corresponding symbol from the reference DL resource in the DL resource.

[0158] In other specific embodiments, the terminal determines the reference DL resource regardless of whether all PRBs of the OFDM symbol are set as reserved resources. Specifically, the terminal excludes the OFDM symbol set as the reserved resource for the terminal from the reference DL resource. The PRBs set as the reserved resources are set by the cell-specific RRC signal.

[0159] In the 3GPP NR system, the terminal performs random access using the PRACH. The terminal determines the reference DL resource related to the PRACH transmission. Through the following description, a method for the terminal to determine the reference DL resource related to the PRACH transmission will be described.

[0160] The PRACH for the terminal is set by the base station. The terminal obtains information regarding the PRACH configuration for the terminal from the RMSI (remaining minimum system information). The information regarding the PRACH configuration includes information regarding the PRACH transmission parameter configuration. Specifically, the information regarding the PRACH transmission parameter configuration includes at least one of the PRACH preamble format configuration, the time resource configuration in which the PRACH is transmitted, and the frequency resource configuration in which the PRACH is transmitted. Also, the information regarding the PRACH configuration includes information regarding the configuration of the root sequence and the cyclic shift value of the PRACH preamble.

[0161] Also, depending on whether the terminal transmits the PRACH from a carrier (or cell) in a frequency band of 60 GHz or higher, the conditions for the terminal to transmit the PRACH may be different. A carrier using a frequency band of 60 GHz or lower is referred to as an FR1 carrier, and a carrier using a frequency band of 60 GHz or higher is referred to as an FR2 carrier. A terminal with a semi-static DL / UL configuration set transmits the PRACH only from UL symbols in an FR1 carrier (or cell). If the time resource setting of the PRACH overlaps with a DL symbol or a flexible symbol, a terminal with a semi-static DL / UL configuration set cannot transmit the corresponding PRACH from an FR1 carrier (or cell). A terminal with a semi-static DL / UL configuration set transmits the PRACH only from UL symbols and flexible symbols in an FR2 carrier (or cell). If the time resource setting of the PRACH overlaps with a DL symbol, a terminal with a semi-static DL / UL configuration set cannot transmit the corresponding PRACH from an FR1 carrier (or cell). Also, if the PRACH exists before the SS / PBCH block in an FR2 carrier (or cell), the terminal cannot transmit the PRACH.

[0162] In an FR2 carrier (or cell), when the terminal determines the reference DL resource indicated by the preemption indicator, the terminal determines that the reference DL resource does not include the OFDM symbol configured for PRACH transmission. At this time, based on the RMSI described above, the terminal obtains information regarding the OFDM symbol configured for PRACH transmission. Specifically, the terminal obtains the PRACHConfigurationIndex, which is a cell-specific RRC signal, from the RMSI.

[0163] In other specific embodiments, in the FR1 carrier (or cell) and the FR2 carrier (or cell), when the terminal determines the reference DL resource indicated by the preemption indicator, the terminal determines that the reference DL resource does not include the OFDM symbol configured for PRACH transmission. At this time, based on the above-mentioned RMSI, the terminal obtains information regarding the OFDM symbol configured for PRACH transmission. Specifically, the terminal obtains the PRACHConfigurationIndex, which is a cell-specific RRC signal, from the RMSI.

[0164] In the 3GPP NR system, the information required for the terminal to receive the SS / PBCH block is set by the base station. The terminal determines the reference DL resource related to the SS / PBCH block. Through the following description, a method for the terminal to determine the reference DL resource related to the SS / PBCH block will be described.

[0165] The information required to receive the SS / PBCH block is set by the cell-specific RRC signal. Specifically, the information required to receive the SS / PBCH block is set by the SSB-transmitted-SIB1 of the cell-specific RRC signal. Also, the information required to receive the SS / PBCH block is set by the specific-terminal RRC signal. Specifically, the information required to receive the SS / PBCH block is set by the SSB-transmitted of the specific-terminal RRC signal. If the terminal cannot obtain the information required to receive the SS / PBCH block from the cell-specific RRC signal and the specific-terminal RRC signal, the terminal monitors the pre-determined SS / PBCH block. If the terminal obtains the SSB-transmitted-SIB1 and cannot obtain the SSB-transmitted, the terminal monitors the SS / PBCH block set by the SSB-transmitted-SIB1. If the terminal obtains the SSB-transmitted, the terminal monitors the SS / PBCH block set by the SSB-transmitted.

[0166] The terminal adds the DL SS / PBCH block and the set OFDM symbol to the reference DL resource. As described above, the DL SS / PBCH block and the set symbol are set by at least one of the SSB-transmitted-SIB1, which is a cell-specific RRC signal, and the SSB-transmitted, which is a specific-terminal RRC signal. Specifically, the terminal adds the symbol set with the SS / PBCH block by the cell-specific RRC signal among the OFDM symbols not included in the reference DL resource to the reference DL resource.

[0167] In a specific embodiment, in a cell (or carrier) of FR1, the terminal determines that the reference DL resource does not include the OFDM symbol set with the UL symbol by the cell-specific RRC signal while not setting the SS / PBCH block. The terminal determines the OFDM symbol set with the SS / PBCH block among the DL symbols set by the cell-specific RRC signal, the flexible symbols installed by the cell-specific RRC signal, and the UL symbols set by the cell-specific RRC signal among the OFDM symbols during the preemption monitoring period as the reference DL resource.

[0168] In the cell (or carrier) of FR2, the terminal determines that the reference DL resource does not include the OFDM symbol set as the UL symbol by the cell-specific RRC signal. The terminal determines that the reference DL resource does not include the OFDM symbol for "actual PRACH transmission" among the OFDM symbols set as PRACH. In this specification, "actual PRACH transmission" means the PRACH that the terminal actually transmits according to the above-mentioned PRACH transmission conditions among the PRACHs set for the terminal. Also, as described above, the OFDM symbol is set as PRACH by the cell-specific RRC signal. At this time, the cell-specific RRC signal is RMSI. Specifically, the terminal determines as the reference DL resource the flexible symbol set by the cell-specific RRC signal among the OFDM symbols during the preemption monitoring period, excluding the DL symbol and the OFDM symbol for actual PRACH transmission by the cell-specific RRC signal.

[0169] In such an embodiment, the terminal determines that the reference DL resource does not include the symbol set as PRACH while not being set as the SS / PBCH block. Specifically, the terminal determines as the reference DL resource the DL symbol set by the cell-specific RRC signal, the flexible symbol set by the cell-specific RRC signal excluding the OFDM symbol set as PRACH, and the OFDM symbol set as the SS / PBCH block among the OFDM symbols during the preemption monitoring period. If the OFDM symbol set as the SS / PBCH block by the RRC signal and the OFDM symbol set as PRACH overlap, the terminal regards the corresponding OFDM symbol as the DL symbol. Therefore, if the OFDM symbol set as the SS / PBCH block by the RRC signal and the OFDM symbol set as PRACH overlap, the terminal determines that the reference DL resource includes the corresponding OFDM symbol.

[0170] In the above embodiments, the terminal determines the DL resources based on the OFDM symbols for "actual PRACH transmission" that are not the set OFDM symbols for PRACH. Specifically, the terminal determines that the reference DL resources are not set for the SS / PBCH block and do not include the OFDM symbols for actual PRACH transmission and the set OFDM symbols. In a specific embodiment, the terminal determines as the reference DL resources the DL symbols set by the cell-specific RRC signal among the OFDM symbols during the preemption monitoring period, the flexible symbols set by the cell-specific RRC signal excluding the OFDM symbols arranged for actual PRACH transmission, and the OFDM symbols set for the SS / PBCH block.

[0171] In the three above-described embodiments, it has been described that the terminal determines the reference DL resources in FR2. The terminal determines the reference DL resources not only in FR2 but also in FR1 according to the three above-described embodiments.

[0172] The base station signals the reference DL resources for each preemption indicator using the preemption indicator monitoring period and an offset. The terminal determines the reference DL resources for each preemption indicator based on the preemption indicator monitoring period and the offset. Specifically, the terminal uses the following formula to determine the index of the OFDM symbol corresponding to the reference DL resources. {mT INT -Δ offset ,mT INT +1-Δ offset ,...,(m + 1)T INT -1-Δ offset} At this time, {mT INT ,mT INT +1,...,(m + 1)T INT -1}

[0173] is the index of the OFDM symbol during the preemption indicator monitoring period. Also, Δoffset is an offset. The offset has any one of the values 0, 14, and T. INT Also, the offset is constituted by an RRC signal.

[0174] If the pre - emption indicator indicates the pre - emption availability for each OFDM symbol for each bit, the overhead of the pre - emption indicator may become excessively large. In a specific embodiment, assume that a slot includes 14 OFDM symbols, and the pre - emption indicator indicates whether pre - emption has occurred in the OFDM symbols included in 4 slots. At this time, if the pre - emption indicator indicates the pre - emption availability for each OFDM symbol for each bit, the pre - emption indicator should use a total of 56 bits. The base station sets the pre - emption indicator so as to indicate whether pre - emption has occurred in one or more OFDM symbols for each bit of the pre - emption indicator. For example, one bit of the pre - emption indicator may indicate whether pre - emption has occurred in 4 OFDM symbols. Assuming that a slot includes 14 OFDM symbols and the pre - emption indicator indicates whether pre - emption has occurred in the OFDM symbols included in 4 slots, the pre - emption indicator requires 14 bits. The pre - emption indicator divides all the OFDM symbols corresponding to the reference DL resources into a plurality of groups each indicating one or more OFDM symbols, and indicates whether pre - emption occurs in each part loop with one bit. At this time, the terminal determines that no transmission to the terminal has occurred from one or more OFDM symbols corresponding to the corresponding group according to the value of each bit of the pre - emption indicator. Also, the terminal determines that transmission to the terminal has occurred from one or more OFDM symbols corresponding to the corresponding group according to the value of each bit of the pre - emption indicator. A method for dividing the pre - emption indicator into a plurality of groups each indicating one or more OFDM symbols for all the OFDM symbols corresponding to the reference DL resources will be described with reference to FIGS. 27 to 29.

[0175] FIG. 27 is a diagram showing an OFDM symbol in which a bitmap of a preemption indicator according to an embodiment of the present invention indicates preemption availability. When the reference DL resource includes S OFDM symbols and the preemption indicator has a length of N bits, a method of dividing the S OFDM symbols into N groups and indicating the preemption availability in the S OFDM symbols with N bits will be described. At this time, the terminal determines whether transmission from the base station to the terminal has occurred or not in all of the OFDM symbol(s) belonging to the group corresponding to the bit according to the value of each bit among the N bits of the preemption indicator. Specifically, if any one bit among the N bits of the preemption indicator is the first value, the terminal determines that transmission from the base station to the terminal has occurred in all of the one or more OFDM symbols belonging to the group corresponding to the bit. Also, if any one bit among the N bits of the preemption indicator is the second value, the terminal determines that transmission from the base station to the terminal has not occurred in all of the one or more OFDM symbols belonging to the group corresponding to the bit. Therefore, the terminal receives an additional preemption indicator within the resources scheduled by the base station, and based on the determination as to whether transmission from the base station to the terminal has been performed by preemption, the terminal decodes the resources scheduled by the base station. Specifically, the terminal determines that transmission from the base station to the terminal has occurred in the OFDM symbols of a specific OFDM symbol group according to the preemption indicator. At this time, the terminal performs decoding and combining including the corresponding OFDM symbol group in the scheduled resources. Also, the terminal determines that transmission from the base station to the terminal has not been performed by preemption in all of the OFDM symbols of a specific OFDM symbol group according to the preemption indicator. At this time, the terminal performs decoding and combining excluding the corresponding OFDM symbol(s) in the scheduled resources.

[0176] When including a bitmap that indicates the pre - emption availability of OFDM symbol groups where the pre - emption indicator hits each bit, the base station explicitly signals the index of the OFDM symbol indicated by each bit of the bitmap using the RRC signal. The terminal acquires the index of the OFDM symbol indicated by each bit of the bitmap included in the pre - emption indicator based on the RRC signal. In other specific embodiments, the terminal determines the OFDM symbol indicated by each bit of the bitmap included in the pre - emption indicator according to a pre - specified rule.

[0177] Also, the base station divides S OFDM symbols into N groups in the following way and indicates the pre - emption availability for each of the N groups. At this time, the terminal determines the pre - emption availability for each of the N groups based on the pre - emption indicator. At this time, the S OFDM symbols corresponding to the DL reference resources are grouped into N groups with C symbols in order of time. At this time, C is determined by the following formula. C = ceil(S / N)

[0178] When indexing and displaying S OFDM symbols in order of time from 1 to N, it is shown that the N OFDM symbols are grouped as follows. The first group is {1, 2, …, C}, the second group is {C + 1, C + 2, …, 2*C}, …, the (N - 1) - th group is {(N - 2)*C + 1, (N - 2)*C + 2, …, (N - 1)*C}, and the N - th group is {(N - 1)*C, (N - 1)*C + 1, …, S}.

[0179] In other specific embodiments, the difference between the number of OFDM symbols included in each group is at most 1. Among the N groups, the group of mod(S, N) includes ceil(S / N) OFDM symbols, and the remaining (N - mod(S, N)) groups include floor(S / N) OFDM symbols. Here, mod(a, b) indicates the remainder when a is divided by b. In this specification, unless otherwise specifically mentioned, mod(a, b) indicates the remainder when a is divided by b. floor(x) indicates the largest integer among the pivots that are the same as or smaller than x. In this specification, unless otherwise specifically mentioned, floor(x) indicates the largest integer among the numbers that are the same as or smaller than x.

[0180] As described above, the OFDM symbols included in the reference DL resource are continuous. At this time, when the S OFDM symbols included in the reference DL resource are indexed in time order as if they are continuous, the S OFDM symbols are divided into N groups according to the above two embodiments. However, in such an embodiment, a plurality of non - continuous OFDM symbols are classified into one group. Also, the probability that a plurality of non - continuous OFDM symbols are simultaneously punctured by pre - emption is low. Nevertheless, the pre - emption availability is signaled for one group.

[0181] In other specific embodiments, the S OFDM symbols included in the reference DL resource are grouped into N groups including continuous OFDM symbols. Specifically, each individual group includes only continuous OFDM symbols. For the convenience of explanation, the number of OFDM symbols included in each group is represented as S1, S2, …, S M and the number of bits of the pre - emption indicator corresponding to each group is represented as N1, N2, …, N M respectively. At this time, N1 + N2 + … + N Msatisfies =N. The number of bits of the preemption indicator corresponding to each group is determined based on the number of OFDM symbols included in each group. Specifically, the number of bits of the preemption indicator corresponding to each group is proportional to the number of OFDM symbols included in each group. Specifically, for the remaining groups except the last group, the number of bits of the preemption indicator corresponding to each group is determined by the following formula. N i =round(N - M)*S i / S)+1 At this time, i indicates the index of each group. Also, round(x) indicates the integer closest to x. In this specification, unless otherwise specifically mentioned, round(x) indicates the integer closest to x. Also, round(x) may be changed to floor(x) indicating a downward operation or ceil(x) indicating an upward operation. For the last group, the number of bits of the preemption indicator corresponding to the last group is determined by the following formula. N M =N-(N1 + N2 + … + N M-1 )。

[0182] In other specific embodiments, for the remaining groups except the last group, the number of bits of the preemption indicator corresponding to each group is determined by the following formula. N i =round(N*S i / S) At this time, i indicates the index of each group. Also, round(x) indicates the integer closest to x. Also, round(x) may be changed to floor(x) indicating a downward operation or ceil(x) indicating an upward operation. The number of bits of the preemption indicator corresponding to the last group is determined by the following formula. N M =N-(N1 + N2 + … + N M-1 )。

[0183] In the above-described embodiments, each group includes consecutive OFDM symbols. However, OFDM symbols included in different slots are included in one group together. For example, the last OFDM symbol in the (n - 3)-th slot and the first OFDM symbol in the (n - 2)-th slot are included in one group. Different transport blocks (TBs) are assigned to OFDM symbols included in different slots. Therefore, in a specific embodiment, each group includes only OFDM symbols included in the same slot. For example, the terminal and the base station may consider OFDM symbols included in different slots as discontinuous in relation to the grouping of pre-emphasis indicators.

[0184] In the above-described embodiments, the order of the group indices is determined according to the time order of the OFDM symbols included in the group. Therefore, the first group is located earliest in time in the reference DL resource and includes S1 consecutive OFDM symbols. Also, the last group includes S M consecutive OFDM symbols that are located latest in time in the reference DL resource. In other specific embodiments, the order of the group indices is determined in ascending order in the time order of the OFDM symbols included in each group. Therefore, the first group includes the smallest number of OFDM symbols, and the last group includes the largest number of OFDM symbols. In other specific embodiments, the order of the group indices is determined in descending order in the time order of the OFDM symbols included in each group. Therefore, the first group includes the largest number of OFDM symbols, and the last group includes the smallest number of OFDM symbols. If the number of consecutive symbols is the same, the previous group includes the OFDM symbols located earlier in the time domain. In the above-described embodiments, some embodiments will be described in detail with reference to FIG. 27.

[0185] In the embodiment of FIG. 27, the base station receives a control channel including a preemption indicator every two slots. Each slot includes 14 OFDM symbols. Therefore, the preemption indicator transmitted from the nth slot indicates whether the DL resources from the (n - 2)th slot and the (n - 1)th slot are punctured by preemption. In FIG. 27, if the preemption indicator corresponds to the first type (Type #1), the preemption indicator indicates all the OFDM symbols including the slot. Therefore, the preemption indicator divides 28 OFDM symbols in total into N groups, allowing the difference in the number of OFDM symbols included in each group to be only one. If N is 4, the preemption indicator indicates four groups including seven OFDM symbols. At this time, the first bit of the preemption indicator indicates whether at least one of the OFDM symbols from the first OFDM symbol to the seventh OFDM symbol in the (n - 2)th slot is punctured by preemption. Also, the second bit of the preemption indicator indicates whether at least one of the OFDM symbols from the eighth OFDM symbol to the fourteenth OFDM symbol in the (n - 2)th slot is punctured by preemption. Also, the third bit of the preemption indicator indicates whether at least one of the OFDM symbols from the first OFDM symbol to the seventh OFDM symbol in the (n - 1)th slot is punctured by preemption. Also, the fourth bit of the preemption indicator indicates whether at least one of the OFDM symbols from the eighth OFDM symbol to the fourteenth OFDM symbol in the (n - 1)th slot is punctured by preemption. However, in the (n - 1)th slot, since the eighth OFDM symbol to the fourteenth OFDM symbol are not used as DL resources, the fourth bit of the preemption indicator indicates unnecessary information.

[0186] In FIG. 27, if the preemption indicator corresponds to Type #2 or Type #3, the preemption indicator indicates only the OFDM symbols among the OFDM symbols included in the slot that can be preempted. At this time, the terminal determines the reference DL resource based on the setting of the OFDM symbols included in the slot and the RRC signal. The 10th OFDM symbol from the first OFDM symbol of the n-2th slot and the 2nd OFDM symbol from the first OFDM symbol of the n-1th slot correspond to the reference DL resource. Therefore, the number of OFDM symbols that the preemption indicator should indicate is 12. If the preemption indicator corresponds to Type #2, regardless of whether the OFDM symbols included in one group are consecutive, a plurality of OFDM symbols corresponding to the reference DL resource are grouped. Also, the difference in the number of OFDM symbols included in each group is at most one. Specifically, 12 OFDM symbols indicate 4 groups each including 3 OFDM symbols. Specifically, the first bit of the bitmap of the preemption indicator indicates whether at least any one of the OFDM symbols from the 3rd OFDM symbol to the first OFDM symbol of the n-2th slot has been punctured by preemption. Also, the second bit of the bitmap of the preemption indicator indicates whether at least any one of the OFDM symbols from the 4th OFDM symbol to the 6th OFDM symbol of the n-2th slot has been punctured by preemption. Also, the third bit of the bitmap of the preemption indicator indicates whether at least any one of the OFDM symbols from the 7th OFDM symbol to the 9th OFDM symbol of the n-2th slot has been punctured by preemption.Also, the fourth bit of the bitmap of the preemption indicator indicates whether at least one of the OFDM symbols from the 10th OFDM symbol in the (n - 2)-th slot and the first OFDM symbol to the second OFDM symbol in the (n - 1)-th slot in the (n - 1)-th slot is punctured by preemption. In the embodiment of FIG. 27, when the preemption indicator corresponds to the second type (Type #2), different from the case where the preemption indicator corresponds to the first type (Type #1), the preemption indicator does not indicate unnecessary information. However, the fourth group includes OFDM symbols included in different slots. Therefore, the preemption indicator indicates the possibility of preemption of OFDM symbols included in different slots with one bit. Such a method of the second type (Type #2) is to transmit the preemption indicator in resources that may be substantially preempted, so that, under the assumption that the terminal does not receive transmissions from the base station for resources that are not likely to be preempted unnecessarily, the transmission rate generated by decoding and combining is prevented from decreasing.

[0187] When the preemption indicator corresponds to the third type (Type #3), assuming that all OFDM symbols included in one group are consecutive, a plurality of OFDM symbols corresponding to the reference DL resources are grouped. In the embodiment of FIG. 27, they are divided into 10 consecutive OFDM symbols and two OFDM symbols. At this time, the number of bits (N1) of the preemption indicator indicating 10 consecutive OFDM symbols is obtained based on the following formula. N1 = round((N - 2)*S1 / S)+1 At this time, S is the total number of OFDM symbols corresponding to the DL reference resource. Also, S1 is the number of initially consecutive OFDM symbols. Also, N is the total number of bits of the preamble indicator. Thus, if the preamble indicator corresponds to the third type (Type #3), 10 OFDM symbols are indicated by 3 bits and 2 OFDM symbols are indicated by 1-bit. Specifically, the first bit of the bitmap of the preamble indicator indicates whether at least one of the OFDM symbols from the first OFDM symbol to the fourth OFDM symbol of the n-2nd slot has been punctured by preamble. Also, the second bit of the bitmap of the preamble indicator indicates whether at least one of the OFDM symbols from the fifth OFDM symbol to the seventh OFDM symbol of the n-2nd slot has been punctured by preamble. Also, the third bit of the bitmap of the preamble indicator indicates whether at least one of the OFDM symbols from the eighth OFDM symbol to the tenth OFDM symbol of the n-2nd slot has been punctured by preamble. Also, the fourth bit of the bitmap of the preamble indicator indicates whether at least one of the OFDM symbols from the first OFDM symbol to the second OFDM symbol of the n-1st slot has been punctured by preamble. If the preamble indicator corresponds to the third type (Type #3), different from the case where the preamble indicator corresponds to the second type (Type #2), it does not indicate OFDM symbols included in different slots by one bit. Such a method of the second type (Type #3) is to transmit the preamble indicator in the resource that may be substantially preambled, so that the terminal can prevent the transmission rate generated by decoding and combining from decreasing under the assumption that the resource that cannot be unnecessarily preambled will not be transmitted from the base station.Also, when transmission to TB in different slots occurs simultaneously, the possibility of non - continuous pre - emption occurring in different slots is low. Therefore, when the base station uses such an embodiment, it can more accurately instruct the terminal about the resources that may be pre - empted.

[0188] FIG. 28 is a diagram showing an OFDM symbol in which a bitmap of a pre - emption indicator according to another embodiment of the present invention indicates whether pre - emption is possible. In another specific embodiment of the present invention, the base station divides the reference DL resource into a plurality of sub - reference DL resources, and further divides the sub - reference DL resources into a plurality of groups to indicate whether pre - emption is possible. Specifically, the pre - emption indicator indicates one of the plurality of sub - reference DL resources included in the reference DL resource, and indicates whether pre - emption is possible for each of the plurality of groups included in the sub - reference DL resource. At this time, the pre - emption indicator includes a first field that indicates one of the plurality of sub - reference DL resources and a second field that indicates whether pre - emption is possible for the plurality of groups included in the indicated sub - reference DL resource. At this time, the second field is set by the method of setting the bitmap of the pre - emption indicator described in the above - mentioned embodiment. The terminal determines the sub - reference DL resource indicated by the pre - emption indicator based on the pre - emption indicator, and determines whether pre - emption is possible for the plurality of groups included in the sub - reference DL resource based on the pre - emption indicator. Specifically, the terminal determines the sub - reference DL resource indicated by the pre - emption indicator based on the first field, and determines whether pre - emption is possible for the plurality of groups included in the sub - reference DL resource based on the second field. The sub - reference DL resource includes a specified number of OFDM symbols. At this time, the specified number is the number of OFDM symbols included in one slot. Also, the sub - reference DL resource is limited to including only consecutive OFDM symbols.

[0189] In the embodiment of FIG. 28, the first bit of the preemption indicator indicates the sub-reference DL resource where preemption occurred, and the second bit is a bitmap indicating whether preemption occurred in each of the multiple groups included in the sub-reference DL resource. At this time, the first sub-reference DL resource is a set of OFDM symbols located in the (n - 2)-th slot among the reference DL resources. Also, the second sub-reference DL resource is a set of OFDM symbols located in the (n - 1)-th slot among the reference DL resources. If the preemption indicator indicates the first sub-reference DL resource, the first bit of the bitmap of the second bit of the preemption indicator indicates whether at least one of the OFDM symbols from the first OFDM symbol to the fifth OFDM symbol in the (n - 2)-th slot was punctured by preemption. Also, if the preemption indicator indicates the first sub-reference DL resource, the second bit of the bitmap of the second bit of the preemption indicator indicates whether at least one of the OFDM symbols from the sixth OFDM symbol to the tenth OFDM symbol in the (n - 2)-th slot was punctured by preemption. Also, if the preemption indicator indicates the second sub-reference DL resource, the first bit of the bitmap of the second bit of the preemption indicator indicates whether the first OFDM symbol in the (n - 1)-th slot was punctured by preemption. Also, if the preemption indicator indicates the second sub-reference DL resource, the second bit of the 2-bit bitmap of the preemption indicator indicates whether the second OFDM symbol in the (n - 1)-th slot was punctured by preemption.

[0190] In the embodiment of FIG. 28, the terminal receives a first bit and a second bit as additional preemption indicators from within the resources scheduled by the base station, and determines whether preemption has occurred for each of a plurality of groups including the sub-reference DL resources indicated by the base station. At this time, the terminal decodes the scheduled resources according to a determination as to whether transmission to the terminal has occurred from the base station.

[0191] FIG. 29 is a diagram showing an OFDM symbol in which a bitmap of a preemption indicator according to another embodiment of the present invention indicates preemption availability. The base station signals, using RRC configuration, how many OFDM symbols out of the group indicated to the terminal via the preemption indicator are to be configured into one group. Specifically, the base station signals the time-domain OFDM symbol granularity to the terminal using RRC configuration. The terminal determines, using RRC configuration, how many OFDM symbols the preemption indicator configures into one group. Further, the terminal determines the group of OFDM symbols indicated by each bit of the bitmap of the preemption indicator based on the setting of the OFDM symbols included in the slot and how many OFDM symbols the preemption indicator configures into one group. If the reference DL resource includes S OFDM symbols and the OFDM symbol granularity is C, the terminal determines that ceil(S / C) bits are used as a bitmap by the preemption indicator. At this time, it is assumed that the preemption indicator indicates S OFDM symbols in order. At this time, if 1≦i<ceil(S / C) is satisfied, the terminal determines that the i-th bit of the bitmap of the preemption indicator indicates that at least one of the OFDM symbols from the (C*(i - 1)+1)-th OFDM symbol to the C*i-th OFDM symbol is punctured by preemption. Also, if i satisfies i = ceil(S / C), the terminal determines that the i-th bit of the preemption indicator indicates that at least one of the OFDM symbols from the (C*(i - 1)+1)-th OFDM symbol to the S-th OFDM symbol is punctured by preemption. Further, the preemption indicator includes bits indicating which PRB is punctured by preemption.

[0192] In the embodiment of FIG. 29, the OFDM symbols from the first OFDM symbol to the tenth OFDM symbol of the n-2nd slot and the first OFDM symbol to the second OFDM symbol of the n-1st slot correspond to the reference DL resources. At this time, the OFDM symbol granularity is 3. In the first case (case #1), the preemption indicator includes a 4-bit bitmap. The first bit of the bitmap of the preemption indicator indicates whether at least one of the OFDM symbols from the first OFDM symbol to the third OFDM symbol of the n-2nd slot has been punctured by preemption. Also, the second bit of the bitmap indicates whether at least one of the OFDM symbols from the fourth OFDM symbol to the sixth OFDM symbol of the n-2nd slot has been punctured by preemption. Also, the third bit of the bitmap indicates whether at least one of the OFDM symbols from the seventh OFDM symbol to the ninth OFDM symbol of the n-2nd slot has been punctured by preemption. Also, the fourth bit of the bitmap indicates whether at least one of the tenth OFDM symbol of the n-2nd slot, the first OFDM symbol and the second OFDM symbol of the n-1st slot has been punctured by preemption.

[0193] In the above-described embodiments, each group is restricted to include only consecutive OFDM symbols. At this time, the terminal determines the OFDM symbol group indicated by each bit of the bitmap of the preemption indicator on the premise that each group includes only consecutive OFDM symbols. For example, it may be assumed that the reference DL resource includes S OFDM symbols, and S1 of the S OFDM symbols are consecutive. At this time, the granularity of the OFDM symbols signaled by the RRC signal is C. The terminal determines that ceil(S1 / C) + ceil(S2 / C) bits are used for the preemption indicator. Specifically, if 1 ≤ i < ceil(S1 / C) is satisfied, the terminal determines that the i-th bit of the bitmap of the preemption indicator indicates whether at least one of the OFDM symbols from the (C*(i - 1) + 1)-th OFDM symbol to the C*i-th OFDM symbol is punctured by preemption. Also, if i satisfies ceil(S1 / C) + 1 ≤ i < ceil(S1 / C) + ceil(S2 / C), the terminal determines that the i-th bit of the bitmap of the preemption indicator indicates whether at least one of the OFDM symbols from the (S1 + C*(i - 1) + 1)-th OFDM symbol to the (S1 + C*i)-th OFDM symbol is punctured by preemption. If i = ceil(S1 / C) + ceil(S2 / C) is satisfied, the terminal determines that the i-th bit of the bitmap of the preemption indicator indicates whether at least one of the OFDM symbols from the (S1 + C*(i - 1) + 1)-th OFDM symbol to the (S1 + S2)-th OFDM symbol is punctured by preemption.

[0194] In case #2 of the embodiment of FIG. 29, the preemption indicator includes a 5-bit bitmap. The first bit of the bitmap of the preemption indicator indicates whether at least one of the OFDM symbols from the third OFDM symbol to the first OFDM symbol in the n-2nd slot is punctured by preemption. The second bit of the bitmap indicates whether at least one of the OFDM symbols from the sixth OFDM symbol to the fourth OFDM symbol in the n-2nd slot is punctured by preemption. The third bit of the bitmap indicates whether at least one of the OFDM symbols from the ninth OFDM symbol to the seventh OFDM symbol in the n-2nd slot is punctured by preemption. The fourth bit of the bitmap indicates whether the tenth OFDM symbol in the n-2nd slot is punctured by preemption. The fifth bit of the bitmap indicates whether at least one of the OFDM symbols from the second OFDM symbol to the first OFDM symbol in the n-1st slot is punctured by preemption. Such case #2 is to transmit a preemption indicator in resources that may be substantially preempted. Therefore, in such case #2, the base station prevents a decrease in the data transmission rate that occurs by decoding and combining under the assumption that the terminal does not transmit from the base station for resources that are not likely to be unnecessarily preempted. Also, when transmissions for TBs occur in different slots simultaneously, the possibility of non-consecutive preemption occurring in different slots is low. Therefore, in such an embodiment, the base station can more accurately indicate to the terminal the resources that may be preempted.

[0195] In the setting of the same OFDM symbol, the terminal determines the OFDM symbol group indicated by each bit of the preamble indicator bitmap according to the following embodiments. S1 OFDM symbols are divided into N1 = ceil(S1 / C) groups. At this time, among the ceil(S1 / C) groups, the first mod(S1, N1) groups each contain C OFDM symbols, and the remaining N1 - mod(S1, N1) groups each contain C - 1 OFDM symbols. Also, S2 OFDM symbols are divided into N2 = ceil(S2 / C) groups. At this time, among the ceil(S2 / C) groups, the first mod(S2, N2) groups each contain C OFDM symbols, and the remaining N2 - mod(S2, N2) groups each contain C - 1 OFDM symbols.

[0196] In case #3 of the embodiment of FIG. 29, the preemption indicator includes a 5-bit bitmap. The first bit of the bitmap of the preemption indicator indicates whether at least one of the OFDM symbols from the 3rd OFDM symbol to the first OFDM symbol of the (n-2)th slot is punctured by preemption. Also, the second bit of the bitmap indicates whether at least one of the OFDM symbols from the 6th OFDM symbol to the 4th OFDM symbol of the (n-2)th slot is punctured by preemption. Also, the third bit of the bitmap indicates whether at least one of the OFDM symbols from the 8th OFDM symbol to the 7th OFDM symbol of the (n-2)th slot is punctured by preemption. Also, the fourth bit of the bitmap indicates whether at least one of the OFDM symbols of the 9th and 10th OFDM symbols of the (n-2)th slot is punctured by preemption. Also, the fifth bit of the bitmap indicates whether at least one of the OFDM symbols of the first and second OFDM symbols of the (n-1)th slot is punctured by preemption. Such case #3 transmits a preemption indicator that indicates resources that may be substantially preempted. Thus, the base station prevents a decrease in the transmission rate of data generated by decoding and combining under the assumption that the terminal does not transmit from the base station resources that are not likely to be preempted. Also, when transmissions for TBs occur in different slots at the same time, the possibility of non-continuous preemption occurring in different slots is low. Thus, the base station can more accurately indicate to the terminal resources that may be preempted.In such an embodiment, the base station divides, in the OFDM symbol unit, the resources in the same slot where preemption may additionally occur into the most equal groups, that is, divides them such that the difference in the length of the OFDM symbols in each group allows only a minimum of one. Therefore, even when the minimum number of pre-emptions occurs in the OFDM symbol unit, the base station can maximize the prevention of a decrease in the data transmission rate.

[0197] In the embodiment of FIG. 29, the terminal additionally receives a preemption indicator from within the resources scheduled by the base station, and determines whether preemption has occurred for each of a plurality of groups including the sub-reference DL resources indicated by the base station. The terminal decodes the scheduled resources according to the determination as to whether transmission from the base station to the terminal has occurred.

[0198] The terminal determines the size of the payload of the preemption indicator based on the RRC signal. Specifically, the terminal determines the size of the payload of the preemption indicator explicitly or implicitly based on the RRC signal. If the size of the payload of the preemption indicator is smaller than the size of the payload indicated by the RRC signal, the base station adds padding as some unnecessary (redundant) values to the payload of the preemption indicator, and also adjusts the size of the payload of the preemption indicator and the size of the payload indicated by the RRC signal to be the same. The unnecessary value is 0. In other specific embodiments, the unnecessary value is 1.

[0199] The reference DL resources are divided into a plurality of groups not only in the time domain but also in the frequency domain. Related embodiments will be described. If the reference DL resource includes S OFDM symbols and includes B PRBs, the reference DL resource is divided into N in the time domain and F in the frequency domain. The S OFDM symbols are divided into N groups, and the B PRBs are divided into F groups. Therefore, the reference DL resource is divided into NxF groups. The preemption indicator includes NxF bits, and the terminal determines that preemption has occurred from the group of reference DL resources where each of the NxF bits corresponds to a bit. In a specific embodiment, N = 14 and F = 1. Also, N = 7 and F = 2 may be used. Further, the base station uses the RRC signal to set the values of N and F. The terminal obtains the values of N and F based on the RRC signal.

[0200] If N = 14 and F = 1, the terminal divides the B PRBs into one group. Also, if N = 7 and F = 2, the terminal divides ceil(B / 2) of the B PRBs into one group and the remaining B - ceil(B / 2) PRBs into another group. In another specific embodiment, if N = 7 and F = 2, the terminal divides floor(B / 2) of the B PRBs into one group and the remaining B - floor(B / 2) PRBs into another group.

[0201] If the reference DL resource includes S OFDM symbols, the terminal divides the reference DL resource into N groups according to the following embodiments. If N≥S, the S OFDM symbols are divided into S groups, and each of the S×F bits of the preamble indicator indicates whether preamble occurs in each group. At this time, the base station pads the remaining (N - S)×F bits of the preamble indicator with unnecessary values to make the size of the preamble indicator N×F bits. The unnecessary value is 0. In other specific embodiments, the unnecessary value is 1. The specific embodiment when N < S is as follows. The terminal groups C = floor(S / N) OFDM symbols in sequence and divides the S OFDM symbols included in the reference DL resource into N groups. When indexing the S OFDM symbols from 1 in time order, the N groups are shown as follows. The first group is {1, 2, …, C}, the second group is {C + 1, C + 2, …, 2×C}, the (N - 1)-th group is {(N - 2)×C + 1, (N - 2)×C + 2, …, (N - 1)×C}, and the N-th group is {(N - 1)×C, (N - 1)×C + 1, …, S}. At this time, the N groups include more than C OFDM symbols.

[0202] The S OFDM symbols are divided into N groups so that the difference in the number of OFDM symbols included in each group does not exceed 1. When indexing the S OFDM symbols from 1 in time order, the N groups are divided as follows. Among the N groups, the first mod(S, N) groups include ceil(S / N) OFDM symbols, and the remaining N - mod(S, N) groups include floor(S / N) OFDM symbols. At this time, mod(S, N) is represented by S - floor(S / N)×N.

[0203] If the S OFDM symbols include OFDM symbols that are discontinuous in the time domain, the S OFDM symbols are divided into N groups according to the following embodiments. The S OFDM symbols are divided into M groups including OFDM symbols that are continuous in the time domain. Let the number of OFDM symbols included in each group be S1, S2, …, S M be referred to as. The M groups are further divided into a plurality of subgroups. The number of subgroups included in each of the M groups is N1, N2, …, N M represented by. At this time, N1 + N2 + … + N M satisfies N1 + N2 + … + N

[0204] The i-th group is divided into N i subgroups according to the following embodiments. The OFDM symbols included in the i-th group are C i = floor(S i / N i ) OFDM symbols and are divided into N i subgroups. When indexing the S i OFDM symbols in order from 1 in time, the N i subgroups are shown as follows. The first group is {1, 2, …, C i}, the second group is {C i + 1, C i + 2, …, 2 * C i}, the (N i - 1)-th group is {(N - 2) * C i + 1, (N i - 2) * C i + 2, …, (N i - 1) * C i}, and the N i -th group is {(N i - 1) * C i , (N i - 1) * C i + 1, …, S}. At this time, the N i groups include more than C i OFDM symbols.

[0205] At this time, the N iThe number of OFDM symbols included in each subgroup is determined as in the following embodiments. Specifically, the difference in the number of OFDM symbols included in each of the multiple subgroups included in the i-th group is at most one. S i When indexing the S OFDM symbols from 1 in chronological order, N i subgroups are classified as follows. N i Among the N subgroups, the first mod(S i , N i ) groups include ceil(S i / N i ) OFDM symbols, and the remaining N i - mod(S i , N i ) groups include floor(S i / N i ) OFDM symbols.

[0206] If the OFDM symbols corresponding to the reference DL resource are included in two or more slots, the OFDM symbols corresponding to the reference DL resource are classified into N groups according to the following embodiments. First, the S OFDM symbols are classified into M groups including consecutive OFDM symbols for each slot. Let the number of OFDM symbols included in each group be S1, S2,..., S M . The M groups are further classified into multiple subgroups. The number of subgroups included in each of the M groups is represented by N1, N2,..., N M . At this time, N1 + N2 +... + N M ≤ N is satisfied.

[0207] The i-th group is classified into N i subgroups according to the following embodiments. The OFDM symbols included in the i-th group are C i = floor(S i / N i ) OFDM symbols and are classified into N i subgroups. When indexing the S i OFDM symbols from 1 in chronological order, N iThe individual subgroups are shown as follows. The first group is {1, 2, …, C i}, the second group is {C i +1, C i +2, …, 2*C i}, the (N i -1)-th group is {(N-2)*C i +1, (N i -2)*C i +2, …, (N i -1)*C i}, and the N i -th group is {(N i -1)*C i , (N i -1)*C i +1, …, S}. At this time, the N i groups contain more than C i OFDM symbols.

[0208] At this time, the number of OFDM symbols included in the N i subgroups of the i-th group is determined as follows. Specifically, the difference in the number of OFDM symbols included in each of the multiple subgroups included in the i-th group is at most one. When indexing the S i OFDM symbols in order from 1 in time, the N i subgroups are divided as follows. Among the N i subgroups, the first mod(S i , N i ) groups contain ceil(S i / N i ) OFDM symbols, and the remaining N i -mod(S i , N i ) groups contain floor(S i / N i ) OFDM symbols.

[0209] If the monitoring period of the preemption indicator is one slot or more and the OFDM symbols corresponding to the reference DL resources include discontinuous OFDM symbols in the time domain, the OFDM symbols corresponding to the reference DL resources are classified into N groups according to the following example. First, S OFDM symbols are classified into M groups including consecutive OFDM symbols for each slot. The number of OFDM symbols included in each group is denoted as S1, S2, …, S M and so on. The M groups are further divided into a plurality of subgroups. The number of subgroups included in each of the M groups is denoted as N1, N2, …, N M and is represented by. At this time, N1 + N2 + … + N M satisfies N1 + N2 + … + N

[0210] The i-th group is divided into N i subgroups according to the following example. The OFDM symbols included in the i-th group are C i = floor(S i / N i ) and are divided into N i subgroups. When the S i OFDM symbols are indexed from 1 in chronological order, the N i subgroups are shown as follows. The first group is {1, 2, …, C i}, the second group is {C i + 1, C i + 2, …, …, 2 * C i}, the (N i - 1)-th group is {(N - 2) * C i + 1, (N i - 2) * C i + 2, …, (N i - 1) * C i}, and the N i -th group is {(N i - 1) * C i , (N i - 1) * C i + 1, …, S}. At this time, the N i groups include more than C i OFDM symbols.

[0211] At this time, the number of OFDM symbols included in the N i subgroups of the i-th group is determined as in the following embodiments. Specifically, the difference in the number of OFDM symbols included in each of the plurality of subgroups included in the i-th group is at most one. When indexing S i OFDM symbols from 1 in chronological order, the N i subgroups are classified as follows. The first mod(S i , N i ) of the N i subgroups contain ceil(S i / N i ) OFDM symbols, and the remaining N i -mod(S i , N i ) subgroups contain floor(S i / N i ) OFDM symbols.

[0212] The number of subgroups included in each of the M groups is determined based on the number of OFDM symbols included in each of the M groups. Specifically, the number of subgroups included in each of the M groups is determined in proportion to the number of OFDM symbols included in each of the M groups. Specifically, the numbers of subgroups N1, N2,..., N M included in each of the M groups are determined by the following equations. N1 = round((N - M) * S1 / S) + 1, N2 = round((N - M) * S2 / S) + 1,..., N M-1 = round((N - M) * S M-1 / S) + 1, N M = N - (N1 + N2 +... + N M-1 ) In the above equations, the rounding operation round(x) may be replaced by the floor(x + 0.5) indicating the downward operation or the ceil(x - 0.5) indicating the upward operation. In other specific embodiments, the number of subgroups N1, N2, …, N included in each of the M groups M is then determined by the following equations. N1 = round(N * S1 / S), N2 = round(N * S2 / S), …, N M-1 = round(N * S M-1 / S), N M = N - (N1 + N2 + … + N M-1 ) In the above equations, the rounding operation round(x) may be replaced by the floor operation floor(x + 0.5) representing a downward operation or the ceiling operation ceil(x - 0.5) representing an upward operation.

[0213] In the two embodiments described through the above equations, the order of the groups is determined by the order in the time domain of the OFDM symbols. Thus, the first group is located at the front and includes the first S1 consecutive OFDM symbols. The Mth group is located at the end and includes the consecutive S M symbols.

[0214] In a specific embodiment, in the two embodiments described through the above equations, the order of the groups is determined in ascending order in the time domain of the OFDM symbols. Thus, the first group includes the smallest number of consecutive OFDM symbols. The Mth group includes the largest number of consecutive OFDM symbols. According to a specific embodiment, in the two embodiments described through the above equations, the order of the groups is determined in descending order in the time domain of the OFDM symbols. Thus, the first group includes the largest number of consecutive OFDM symbols. The Mth group includes the smallest number of consecutive OFDM symbols. If the number of consecutive symbols is the same, the OFDM symbols located earlier in the time domain are included in the earlier group.

[0215] In other specific embodiments, if the number of OFDM symbols included in each subgroup included in each of the M groups is limited to a number smaller than C, the number of subgroups N1, N2, …, N included in each of the M groups M is determined by the following formula. N1 = ceil(S1 / C), N2 = ceil(S2 / C), …, N M = ceil(S M / C) At this time, C is

[0216]

Number

[0217] the smallest number among the integers that satisfy. In the above formula, ceil(x) represents the ceiling operation.

[0218] In other specific embodiments, if the number of OFDM symbols included in each subgroup included in each of the M groups is limited to a number smaller than C, the number of subgroups N1, N2, …, N included in each of the M groups M is determined by the following formula. N1 = ceil(S1 / C) + a1, N2 = ceil(S2 / C) + a2, …, N M = ceil(S M / C) + a M , At this time, C is

[0219]

Number

[0220] the smallest number among the integers that satisfy. In the above formula, ceil(x) represents the ceiling operation. Also, in the above formula, the value of a i is determined by the following formula.

[0221]

Number

[0222] The indexing of M groups is set to satisfy the following mathematical formula. S1≧S2≧…≧S M

[0223] At this time, if the number of OFDM symbols included in the groups is the same, a lower index is assigned to the group including the OFDM symbol located earlier in the time domain. The number of OFDM symbols included in the subgroups included in each of the M groups is restricted to a number smaller than C, and the number of OFDM symbols included in the subgroups of the group including more OFDM symbols is made lower. In other specific embodiments, the indexing of M groups is set to satisfy the following mathematical formula. S1 / ceil(S1 / C)≧S2 / ceil(S2 / C)≧…≧S M =ceil(S M / C) At this time, if the number of OFDM symbols included in the groups is the same, a lower index is assigned to the group including the OFDM symbol located earlier in the time domain. The number of OFDM symbols included in the subgroups included in each of the M groups is restricted to a number smaller than C, and the number of OFDM symbols included in the subgroups of the group including more OFDM symbols is made lower.

[0224] In other specific embodiments, the indexing of M groups is set to satisfy the following mathematical formula. ceil(S1 / C)≦ceil(S2 / C)≦…≦ceil(S M / C) At this time, if the number of OFDM symbols included in the groups is the same, a lower index is assigned to the group including the OFDM symbol located earlier in the time domain. The number of OFDM symbols included in each subgroup included in each of the M groups is limited to a number smaller than C, and the number of OFDM symbols included in the subgroup of the group including more OFDM symbols is made lower.

[0225] In other specific embodiments, the indexing of the M groups is set to satisfy the following formula. ceil(S1 / C)≧ceil(S2 / C)≧…≧ceil(S M / C) At this time, if the number of OFDM symbols included in the groups is the same, a lower index is assigned to the group including the OFDM symbol located earlier in the time domain. The number of OFDM symbols included in each subgroup included in each of the M groups is limited to a number smaller than C, and the number of OFDM symbols included in the subgroup of the group including more OFDM symbols is made lower. In the above formula, the rounding operation round(x) may be replaced with the floor(x + 0.5) indicating the downward operation or the ceil(x - 0.5) indicating the upward operation.

[0226] As described above, the reference DL resource indicated by the preemption indicator includes all the PRBs of the BWP. The preemption indicator divides the reference DL resource into 14 parts and uses a bitmap having 14 bits to indicate whether preemption has occurred in the 14 parts. As described above, the reference DL resource is divided into 14 parts in the time domain. Also, the reference DL resource is divided into 7 parts in the time domain and 2 parts in the frequency domain. Also, the period for which the terminal monitors the preemption indicator is any one of 1 slot, 2 slots, and 4 slots.

[0227] If the terminal is configured to perform carrier aggregation (CA) by aggregating a plurality of component carriers (cells), the terminal monitors a preemption indicator that indicates preemption information of another carrier from one carrier. At this time, the preemption indicator is referred to as a cross-carrier DL preemption indicator. Based on FIG. 30, the transmission period of the preemption indicator will be described in detail.

[0228] FIG. 30 is a diagram showing that if the terminal is configured with CA according to an embodiment of the present invention, the terminal monitors a preemption indicator that indicates information regarding preemption occurring in another carrier on any one carrier.

[0229] The embodiments of FIGS. 30(a) and 30(b) relate to the case where the terminal is set to monitor the preemption indicator in a cell with a subcarrier spacing of 60 KHz, and the preemption indicator is set to indicate information regarding preemption occurring in a cell with a subcarrier spacing of 15 KHz. In a cell with a subcarrier spacing of 60 KHz, depending on the relationship between the OFDM symbol position of the CORESET for monitoring the preemption indicator and the OFDM symbol position of a cell with a subcarrier spacing of 15 KHz, the OFDM symbols corresponding to the reference DL resources are three or four OFDM symbols. Specifically, if the symbol position of the CORESET for monitoring the preemption indicator in a cell with a subcarrier spacing of 60 KHz starts from the first OFDM symbol or the second OFDM symbol position of a cell with a subcarrier spacing of 15 KHz, the OFDM symbols corresponding to the reference DL resources are four OFDM symbols. Also, if the symbol position of the CORESET for monitoring the preemption indicator in a cell with a subcarrier spacing of 60 KHz starts from the third OFDM symbol or the fourth OFDM symbol position of a cell with a subcarrier spacing of 15 KHz, the OFDM symbols corresponding to the reference DL resources are three OFDM symbols. Thus, in a cell with a subcarrier spacing of 60 KHz, the number of OFDM symbols corresponding to the reference DL resources can be different depending on the relationship between the OFDM symbol position of the CORESET for monitoring the preemption indicator and the OFDM symbol position of a cell with a subcarrier spacing of 15 KHz. Also, the number of OFDM symbols during the monitoring period of the preemption indicator is N_symb*T_INT*2 (μ-μ_INT)It is represented by. Here, N_symb is the number of OFDM symbols included in a slot. If normal cyclic prefix (CP) is used, N_symb is 14. If extended CP is used, N_symb is 12. Also, T_INT is the monitoring period of the preamble indicator. Also, T_INT is one of 1, 2, and 4. μ_INT is a value that satisfies that the subcarrier spacing of the carrier on which the DL preamble indicator is transmitted is 15*2 μ_INT KHz. μ is a value that satisfies that the subcarrier spacing of the carrier on which the preamble indicator indicates information regarding preamble is 15*2 μ KHz.

[0230] The base station signals the preamble indicator in integer slot periods. The terminal monitors the preamble indicator in integer slot periods. The base station sets the value of T_INT and the value of μ_INT such that T_INT*2 (μ-μ_INT) is a natural number, and signals the corresponding values to the terminal. The terminal expects the value of T_INT, the value of μ, and the value of μ_INT such that T_INT*2 (μ-μ_INT) is a natural number. The terminal does not expect the value of T_INT, the value of μ, and the value of μ_INT such that T_INT*2 (μ-μ_INT) is a decimal number. In a specific embodiment, if the value of T_INT*2 (μ-μ_INT) is a decimal number, the terminal ignores the value of T_INT. Alternatively, if the terminal receives the value of T_INT, the value of μ, and the value of μ_INT such that T_INT*2 (μ-μ_INT) is a decimal number, the terminal determines the corresponding setting from the base station as an error case. At this time, the terminal does not have to perform any operation. Alternatively, if the terminal has T_INT*2 (μ-μ_INT)If the terminal receives the values of T_INT, μ, and μ_INT for which the value of becomes a decimal, the terminal does not have to perform monitoring to receive the preemption indicator from the base station. Specifically, the terminal does not expect (T_INT, μ, μ_INT) = (1, 0, 1), (T_INT, μ, μ_INT) = (1, 0, 2), or (T_INT, μ, μ_INT) = (2, 0, 2). The base station sets the values of T_INT, μ, and μ_INT such that T_INT * 2 (μ-μ_INT) becomes a natural number.

[0231] Also, the terminal expects the values of T_INT, μ, and μ_INT for which N_symb * T_INT * 2 (μ-μ_INT) becomes a natural number. The terminal does not expect the values of T_INT, μ, and μ_INT for which N_symb * T_INT * 2 (μ-μ_INT) becomes a decimal. According to a specific embodiment, if the value of N_symb * T_INT * 2T_INT * 2 (μ-μ_INT) is a decimal, the terminal ignores the value of T_INT. Alternatively, if the terminal receives the values of T_INT, μ, and μ_INT for which the value of T_INT * 2 (μ-μ_INT) becomes a decimal, the terminal determines the corresponding setting as an error case. At this time, the terminal does not have to perform any operation. Alternatively, if the terminal receives the values of T_INT, μ, and μ_INT for which the value of T_INT * 2 (μ-μ_INT) becomes a decimal, the terminal does not have to perform monitoring to receive the preemption indicator from the base station. For example, if N_symb = 14, the terminal does not expect (T_INT, μ, μ_INT) = (2, 0, 2). The base station sets the values of T_INT, μ, and μ_INT such that N_symb * T_INT * 2 (μ-μ_INT) becomes a natural number.

[0232] Also, the terminal expects that the value of μ is greater than or equal to μ_INT. Specifically, the preemption indicator is always transmitted from a carrier with a smaller subcarrier spacing than the carrier for which information regarding preemption is indicated by the preemption indicator. For example, in carriers having subcarrier spacings, a preemption indicator that indicates information regarding preemption of carriers having a subcarrier spacing of 15 kHz, carriers having a subcarrier spacing of 30 kHz, and carriers having a subcarrier spacing of 60 kHz may be transmitted. From a carrier having a subcarrier spacing of 30 kHz, a preemption indicator that indicates information regarding preemption of carriers having a subcarrier spacing of 30 kHz and carriers having a subcarrier spacing of 60 kHz is transmitted. From a carrier having a subcarrier spacing of 60 kHz, a preemption indicator that indicates information regarding preemption of carriers having a subcarrier spacing of 60 kHz is transmitted. From a carrier having a subcarrier spacing of 30 kHz, a preemption indicator that indicates information regarding preemption of carriers having a subcarrier spacing of 15 kHz is not transmitted. From a carrier having a subcarrier spacing of 60 kHz, a preemption indicator that indicates information regarding preemption of carriers having a subcarrier spacing of 15 kHz and carriers having a subcarrier spacing of 30 kHz is not transmitted.

[0233] In FIG. 30, an example in which the terminal is configured to perform CA has been described. However, the embodiment described via FIG. 30 is also applicable when the terminal operates in one cell (or carrier). Specifically, if a plurality of BWPs configured with different subcarrier settings are used in the terminal and the terminal is configured to monitor preemption indicators in one BWP for other BWPs, the above-described embodiment is applicable. FIGS. 31 to 32 are diagrams showing operation methods of a base station and a terminal according to an embodiment of the present invention.

[0234] The base station generates a preemption indicator for indicating pre-empted (or punctured) resources (S3101). The base station transmits the preemption indicator to the terminal based on a specified period in advance (S3103). Specifically, the base station transmits the preemption indicator at a time corresponding to the specified period in advance. At this time, the base station signals the specified period to the terminal.

[0235] The preemption indicator indicates information regarding the remaining OFDM symbols excluding some of the OFDM symbols included in the OFDM symbols of the slot indicated by the preemption indicator. Specifically, the reference resources indicated by the preemption indicator do not include UL symbols and the set OFDM symbols. At this time, the UL symbol is set in the RRC signal. Specifically, the RRC signal is a cell-specific RRC signal. Also, the preemption indicator indicates only information regarding resources corresponding to DL symbols or flexible symbols that can be DL symbols. The reference resources indicated by the preemption indicator are determined by the embodiments described with reference to FIGS. 21 to 26.

[0236] Also, the preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups, and indicates whether at least any one of the one or more OFDM symbols included in each of the plurality of groups is punctured for each of the plurality of groups. At this time, the number of the plurality of groups is specified in advance. Specifically, the number of the plurality of groups is the number of bits of the bitmap included in the preemption indicator. In other specific embodiments, the number of the plurality of groups is determined by the granularity of the OFDM symbols set by the base station.

[0237] If the number of multiple groups is N and the number of multiple OFDM symbols indicated by the preemption indicator is S, the base station groups the first mod(S, N) groups out of the N groups so that each group contains ceil(S / N) OFDM symbols, and groups the remaining N - mod(S, N) groups so that each group contains floor(S / N) OFDM symbols. At this time, mod(a, b) is a - floor(a / b)*b, floor(x) is the largest integer that is the same as or smaller than x, and ceil(x) is the smallest integer that is the same as or larger than x. In a specific embodiment, the base station groups the multiple groups indicated by the preemption indicator according to the embodiment described with reference to FIGS. 27 to 29.

[0238] The terminal monitors the preemption indicator in integer slot units. Therefore, the base station transmits the preemption indicator so that the terminal monitors the preemption indicator in integer slot units. Specifically, the number of OFDM symbols during a pre-specified period is represented by N_symb*T_INT*2 (μ-μ_INT) where N_symb is the number of OFDM symbols included in a slot. Also, T_INT is the period during which the terminal monitors the preemption indicator. Also, μ_INT is a value that satisfies the condition that the sub-carrier spacing of the carrier on which the preemption indicator is transmitted is 15*2 μ_INT KHz. Also, μ is a value that satisfies the condition that the sub-carrier spacing of the carrier on which the preemption indicator indicates preemption-related information is 15*2 μ KHz. Therefore, the base station sets the values of T_INT, μ, and μ_INT so that N_symb*T_INT*2 (μ-μ_INT) is a natural number. In a specific embodiment, the base station sets the values of T_INT, μ, and μ_INT according to the embodiment described with reference to FIG. 30.

[0239] In addition, the preemption indicator indicates the entire bandwidth of the BWP used by the terminal. In a specific embodiment, the base station transmits the preemption indicator according to the embodiment described with reference to FIGS. 12 to 20.

[0240] The terminal periodically monitors a preemption indicator that indicates preemption (or punctured) resources (S3201). If the terminal receives the preemption indicator, the terminal determines the preempted resources among the resources scheduled for the terminal based on the preemption indicator (S3203). Specifically, the terminal assumes that transmission is not performed from the resources indicated by the preempted resources among the resources scheduled for the terminal by the preemption indicator. Also, by receiving the preemption indicator, the terminal determines the resources for which preemption has occurred from the base station to the terminal according to the value of the preemption indicator. Therefore, the terminal determines whether transmission from the base station has occurred for the resources indicated by preemption among the scheduled resources. Specifically, the terminal determines that transmission from the base station to the terminal has occurred for one or more OFDM symbols corresponding to each bit via the value of the bits included in the preemption indicator. For example, if the value of any one bit included in the preemption indicator is the first value, the terminal determines that transmission from the base station to the terminal has occurred for one or more OFDM symbols corresponding to the corresponding bit. Also, if the value of any one bit included in the preemption indicator is the second value, the terminal determines that transmission from the base station to the terminal has occurred from one or more OFDM symbols corresponding to the corresponding bit. The terminal decodes the base station downlink data based on the resources for which transmission from the base station to the terminal has occurred. At this time, the data includes at least one of a data channel and a control channel. The preemption indicator indicates information regarding the remaining OFDM symbols excluding some of the OFDM symbols included in the slot indicated by the preemption indicator. Therefore, the terminal determines that the preemption indicator indicates information regarding the remaining OFDM symbols excluding some of the OFDM symbols included in the slot indicated by the preemption indicator. Specifically, the terminal determines the resources indicated by the preemption indicator based on the setting of the OFDM symbols included in the slot indicated by the preemption indicator.Specifically, the terminal determines that the resources indicated by the preemption indicator do not include OFDM symbols configured as UL symbols. At this time, the UL symbols are configured by the RRC signal. Specifically, the RRC signal is a cell-specific RRC signal. Also, the terminal determines that the preemption indicator only indicates information regarding resources corresponding to DL symbols or flexible symbols that can be DL symbols. In other specific embodiments, the terminal determines the resources indicated by the preemption indicator based on the information regarding the OFDM symbols indicated via the preemption indicator. At this time, the terminal obtains the information regarding the OFDM symbols indicated by the preemption indicator from the RRC signal. In a specific embodiment, the terminal determines the resources indicated by the preemption indicator according to the embodiments described with reference to FIGS. 21 to 26.

[0241] Also, the preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups, and indicates whether at least any one of the one or more OFDM symbols included in each of the plurality of groups is punctured or preempted. At this time, the terminal determines whether transmission from the base station to the terminal occurs or does not occur from all of the one or more OFDM symbols included in the group corresponding to any one bit. Specifically, if the value of any one bit is the first value, the terminal determines that transmission from the base station to the terminal has occurred from all of the one or more OFDM symbols included in the group corresponding to the relevant bit. Also, if the value of any one bit is the second value, the terminal determines that no transmission has occurred from all of the one or more OFDM symbols included in the group corresponding to the relevant bit. Also, the number of the plurality of groups is specified in advance. Specifically, the number of the plurality of groups is the number of bits of the bitmap included in the preemption indicator. In other specific embodiments, the number of the plurality of groups is determined by the granularity of the OFDM symbols configured by the base station.

[0242] If the number of multiple groups is N and the number of multiple OFDM symbols indicated by the preemption indicator is S, the terminal determines that among the N groups, the first mod(S, N) groups of the N groups are grouped to include ceil(S / N) OFDM symbols, and the remaining N - mod(S, N) groups are grouped to include floor(S / N) OFDM symbols. At this time, mod(a, b) is a - floor(a / b)*b, floor(x) is the largest integer that is the same as or smaller than x, and ceil(x) is the smallest integer that is the same as or larger than x. In a specific embodiment, the terminal determines that the multiple groups indicated by the preemption indicator are grouped according to the embodiments described with reference to FIGS. 27 to 29.

[0243] The terminal monitors the preemption indicator in integer slot units. Specifically, the number of OFDM symbols during a pre-specified period is represented by N_symb*T_INT*2 (μ-μ_INT) Here, N_symb is the number of OFDM symbols included in a slot. Also, T_INT is the period during which the terminal monitors the preemption indicator. Also, μ_INT is a value that satisfies the condition that the subcarrier spacing of the carrier on which the preemption indicator is transmitted is 15*2 μ_INT KHz. Also, μ is a value that satisfies the condition that the subcarrier spacing of the carrier on which the preemption indicator indicates information regarding preemption is 15*2 μ KHz. Therefore, the terminal expects values of T_INT, μ, and μ_INT such that N_symb*T_INT*2 (μ-μ_INT) becomes a natural number. The terminal ignores values of T_INT, μ, and μ_INT such that N_symb*T_INT*2 (μ-μ_INT) has a non-natural number value. Alternatively, if the terminal receives values of T_INT, μ, and μ_INT such that the value of T_INT*2 (μ-μ_INT) becomes a decimal, the terminal determines the corresponding setting as an error case. At this time, the terminal may not perform any operation. Alternatively, if the terminal receives values of T_INT, μ, and μ_INT such that T_INT*2(μ-μ_INT) If the terminal receives the values of T_INT, μ, and μ_INT that result in a fractional value, the terminal does not have to perform monitoring to receive a preemption indicator from the base station. In a specific embodiment, the terminal expects the values of T_INT, μ, and μ_INT according to the embodiment described with reference to FIG. 30.

[0244] The above description of the present invention is for illustrative purposes, and those of ordinary skill in the technical field to which the present invention pertains should be able to understand that the present invention can be easily changed to other specific forms without changing the technical idea and essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single form may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

[0245] The scope of the present invention is indicated by the claims described below rather than the above detailed description, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and the equivalent concept thereof are included in the scope of the present invention.

Description of Reference Numerals

[0246] 100 Terminal 110 Processor 120 Communication Unit 121 Cellular Communication Interface Card 122 Cellular Communication Interface Card 123 Wireless LAN Interface Card 130 Memory 140 User Interface Unit 150 Display Unit 200 Base Station 210 Processor 220 Communication Module 221 Cellular Communication Interface Card 222 Cellular Communication Interface Card 223 Wireless LAN Interface Card 230 Memory

Claims

1. In a base station of a wireless communication system, a communication module, and a processor for controlling the communication module, wherein the processor generates a preemption indicator for indicating pre-empted resources, transmits the preemption indicator based on a period specified in advance to a terminal of the wireless communication system, resources indicated by the preemption indicator do not include OFDM (Orthogonal Frequency Division Multiplexing) symbols set as uplink (UL) symbols by an RRC (radio resource control) signal Base station.

2. The OFDM symbols configured in the terminal are classified into the UL symbols for uplink transmission, downlink (DL) symbols for downlink transmission, and flexible symbols not set as UL symbols or DL symbols The base station according to claim 1.

3. A cell-specific RRC signal commonly applied to the RRC signal cell The base station according to claim 2.

4. The preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups, and indicates whether at least one of the one or more OFDM symbols included in each of the plurality of groups is punctured The base station according to claim 1.

5. The number of the plurality of groups is specified in advance The base station according to claim 4.

6. The number of the plurality of groups is N. If the number of OFDM symbols indicated by the preemption indicator is S, the processor groups the first mod(S, N) groups of the N groups to include ceil(S / N) OFDM symbols, and the remaining N - mod(S, N) groups are grouped to include floor(S / N) OFDM symbols, where mod(a, b) = a - floor(a / b)*b, floor(x) is the largest integer that is the same as or smaller than x, ceil(x) is the smallest integer that is the same as or larger than x The base station according to claim 4.

7. The number of OFDM symbols during the previously specified period is N_symb * T_INT * 2 (μ－μ＿ＩＮＴ) where The N_symb is the number of OFDM symbols included in a slot, the T_INT is the period in which the terminal monitors the preemption indicator, μ_INT is a value that satisfies the condition that the sub - carrier interval of the carrier on which the pre - emphasis indicator is transmitted is 15 * 2 μ＿ＩＮＴ kHz, μ is a value that satisfies that the sub-carrier interval of the carrier for which the pre-emphasis indicator indicates information regarding pre-emphasis is 15 * 2 μ kHz, the processor, the value of T_INT, the value of μ, and the value of μ_INT are set so that N_symb * T_INT * 2 (μ－μ＿ＩＮＴ) becomes a natural number the base station according to claim 1.

8. the preemption indicator, indicates the entire bandwidth of the BWP (bandwidth part) used by the terminal, the BWP is a frequency band in which the terminal transmits and receives with a bandwidth smaller than or equal to the bandwidth of the carrier set for the terminal the base station according to claim 1.

9. In a terminal of a wireless communication system, a communication module, and a processor for controlling the communication module, the processor, periodically monitors a preemption indicator indicating resources preempted by a base station of the wireless communication system, if the preemption indicator is received, determines that the resources indicated by the preemption indicator do not include OFDM symbols set as uplink symbols by an RRC signal, determines resources in which transmission from the base station to the terminal has occurred among the resources scheduled for the terminal based on the preemption indicator, and decodes data received from the base station based on the determination of the resources in which transmission from the base station to the terminal has occurred a terminal.

10. The OFDM symbols configured in the terminal are classified into the UL symbols for uplink transmission, downlink symbols for downlink transmission, UL symbols, and flexible symbols not set as UL symbols or DL symbols the terminal according to claim 9.

11. the RRC signal is a cell-common RRC signal commonly applied to a cell the terminal according to claim 10.

12. the preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups, the processor determines whether transmission from the base station to the terminal has occurred in one or more OFDM symbols included in each of the plurality of groups for each of the plurality of groups the terminal according to claim 9.

13. the number of the plurality of groups is specified in advance the terminal according to claim 12.

14. If the number of the plurality of groups is N and the number of a plurality of OFDM symbols indicated by the preemption indicator is S, the processor determines that among the N groups, the first mod(S, N) groups include ceil(S / N) OFDM symbols, and the remaining N - mod(S, N) groups include floor(S / N) OFDM symbols. The mod(a, b) is a - floor(a / b)*b. The floor(x) is the largest integer that is the same as or smaller than x. The ceil(x) is the smallest integer that is the same as or larger than x. The terminal according to claim 12.

15. The number of OFDM symbols during the period for monitoring the pre - emphasis indicator is N_symb * T_INT * 2 (μ－μ＿ＩＮＴ) where The N_symb is the number of OFDM symbols included in a slot. The T_INT is the monitoring period of the preemption indicator. μ_INT is a value that satisfies the condition that the sub-carrier interval of the carrier through which the pre-emphasis indicator is transmitted is 15 * 2 μ＿ＩＮＴ kHz, μ is a value that satisfies the condition that the sub-carrier interval of the carrier for which the pre-emphasis indicator indicates information regarding pre-emphasis is 15 * 2 μ kHz, The processor the value of T_INT, the value of μ, and the value of μ_INT for which N_symb * T_INT * 2 becomes a natural number are expected (μ－μ＿ＩＮＴ) ​ The terminal according to claim 9.

16. The preemption indicator indicates the entire bandwidth of the BWP used by the terminal, wherein the BWP is a frequency band in which the terminal performs transmission and reception with a bandwidth smaller than or equal to the bandwidth of a carrier set for the terminal. The terminal according to claim 9.

17. In a method of operating a terminal of a wireless communication system, a step of periodically monitoring a preemption indicator that indicates resources preempted from a base station of the wireless communication system; a step of, if the preemption indicator is received, determining that the resources indicated by the preemption indicator do not include uplink symbols and OFDM symbols set as RRC signals; a step of, if the preemption indicator is received, determining, based on the preemption indicator, resources in which transmission from the base station to the terminal has occurred among the resources scheduled for the terminal; and a step of decoding data received from the base station based on a determination of resources in which transmission from the base station to the terminal has occurred. Operating method.

18. The OFDM symbols configured in the terminal are classified into the UL symbols for uplink transmission, downlink symbols for downlink transmission, UL symbols, and flexible symbols not set as UL symbols or DL symbols. The operating method according to claim 17.

19. The RRC signal is a cell-common RRC signal that is commonly applied to the cell. The operation method according to claim 18.

20. The preamble indicator divides a plurality of OFDM symbols indicated by the preamble indicator into a plurality of groups. The step of determining the resource in which the transmission from the base station to the terminal has occurred is as follows. The step includes determining, for each of the plurality of groups, whether the transmission from the base station to the terminal has occurred in one or more OFDM symbols included in each of the plurality of groups. The operation method according to claim 17.

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