Method, device, and system for transmitting and receiving data and control channels in a 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, and more particularly to a wireless communication method, apparatus and system for transmitting and receiving data and control channels. [Background technology]

[0002] The 3GPP NR (3rd Generation Partnership Project New Radio) system improves the spectrum efficiency of the network, allowing operators to provide more data and voice services with a given bandwidth. Thus, the 3GPP NR system is designed to meet the demand for high-speed data and media transmission in addition to large-capacity voice support. The advantages of the NR system are that it has a simple architecture and low operating costs, such as high throughput, low latency, support for Frequency Division Duplex (FDD) and Time Division Duplex (TDD), and improved end user environment on the same platform.

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

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

[0005] The technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Means for solving the problem]

[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 a preempted resource and transmits the preemption indicator to a terminal of the wireless communication system based on a periodicity specified in advance. In this case, the resource indicated by the preemption indicator does not include an orthogonal frequency divisional multiplexing (OFDM) symbol set as an uplink (UL) symbol by a radio resource control (RRC) signal.

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

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

[0009] The number of the plurality of groups is specified in advance. If the number of the groups is N and 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 groups the remaining N-mod(S,N) groups to include floor(S / N) OFDM symbols, where mod(a,b) is a-floor(a / b)*b, floor(x) is the largest integer less than or equal to x, and ceil(x) is the smallest integer less than or equal to x.

[0010] The preemption indicator is monitored by the terminal every integer number of slots. The number of OFDM symbols during the predetermined period is N_symb*T_INT*2 (μ-μ_INT) The N_symb is the number of OFDM symbols included in a slot, the T_INT is a period during which the terminal monitors the preemption indicator, and μ_INT is a subcarrier interval of the carrier on which the preemption indicator is transmitted, which is 15*2 μ_INT KHz, and μ is the subcarrier spacing of the carrier that indicates the preemption information by the preemption indicator. μ The processor is configured to convert the N_symb*T_INT*2 (μ-μ_INT) The values ​​of T_INT, μ, and μ_INT are set so that is a natural number.

[0011] The preemption indicator indicates the entire bandwidth of a BWP (bandwidth part) used by the terminal. The BWP is a frequency band in which the terminal transmits and receives data with a bandwidth smaller than or equal to the bandwidth of a 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 for controlling the communication module. The processor periodically monitors a preemption indicator indicating a preempted resource from a base station of the wireless communication system, and when the processor receives the preemption indicator, determines that the resource indicated by the preemption indicator does not include an OFDM symbol set as an uplink symbol by an RRC signal, determines a resource in which a transmission from the base station to the terminal occurs among resources scheduled for the terminal based on the preemption indicator, and decodes data received from the base station based on the determination of the resource in which a transmission from the base station to the terminal occurs.

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

[0014] The RRC signal is a cell-common RRC signal commonly applied to cells. The preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups, and the processor determines, 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.

[0015] The number of the plurality of groups is specified in advance. If the number of the 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, where mod(a,b) is a-floor(a / b)*b, floor(x) is the largest integer less than or equal to x, and ceil(x) is the smallest integer less than or equal to x. The processor monitors the preemption indicator in units of an integer number of slots.

[0016] The number of OFDM symbols during the period for monitoring the preemption indicator is N_symb*T_INT*2 (μ-μ_INT) The N_symb is the number of OFDM symbols included in a slot, the T_INT is a monitoring period of the preemption indicator, and μ_INT is a subcarrier interval of the carrier in which the preemption indicator is transmitted, which is 15*2 μ_INT KHz, and μ is the subcarrier spacing of the carrier that indicates the preemption information by the preemption indicator. μ The processor is configured to convert the N_symb*T_INT*2 (μ-μ_INT) We expect the values ​​of T_INT, μ, and μ_INT to be natural numbers.

[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 data with a bandwidth smaller than or equal to the bandwidth of the carrier configured for the terminal.

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

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

[0020] The preemption indicator divides a plurality of OFDM symbols indicated by the preemption indicator into a plurality of groups, and the step of determining resources in which transmission from the base station to the terminal occurs includes the step of 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. Effect of the Invention

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

[0022] The effects obtained by the present invention are not limited to those described above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a diagram illustrating an example of a radio frame structure used in a wireless communication system. [Diagram 2] 1 is a diagram illustrating an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. [Diagram 3] A diagram to explain the physical channels used in the 3GPP system and a general signal transmission method using the physical channels. [Figure 4] FIG. 1 is a diagram of an SS / PBCH block for initial cell connection in a 3GPP NR system. [Diagram 5] FIG. 1A is a diagram relating to a control information transmission procedure in a 3GPP NR system, and FIG. 1B is a diagram relating to CCE aggregation of PDCCH and multiplexing of PDCCH. [Figure 6] A diagram showing a CORESET (control resource set) in which a PDCCH is transmitted in a 3GPP NR system. [Figure 7] A diagram showing search space allocation per CCE aggregation for a common search space and a UE specific (or Terminal specific) search space. [Figure 8] FIG. 1 is a conceptual diagram explaining carrier aggregation. [Figure 9] FIG. 1 is a diagram for explaining single carrier communication and multi-carrier communication. [Figure 10] A diagram showing an example in which a cross-carrier scheduling technique is applied. [Figure 11]2 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention. [Figure 12] A diagram showing an example of a CORESET according to an embodiment of the present invention in an NR system. [Figure 13] FIG. 13 is a diagram showing an example of a BWP set in a terminal according to an embodiment of the present invention. [Figure 14] A diagram showing an example of a BWP set in a terminal according to an embodiment of the present invention and a CORESET for the BWP. [Figure 15] 13 is a diagram illustrating a method in 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. [Figure 16] 13 is a diagram illustrating a method in which a terminal monitors a preemption indicator based on a CORESET corresponding to a BWP in which a PDSCH is scheduled according to an embodiment of the present invention. [Figure 17] 13 is a diagram illustrating a method of monitoring a preemption indicator based on a CORESET corresponding to a BWP in which a PDSCH is scheduled when multiple BWPs configured in a terminal overlap according to an embodiment of the present invention. [Figure 18] 13 is a diagram illustrating a method in which a terminal monitors a preemption indicator based on a pre-specified BWP according to an embodiment of the present invention. [Figure 19] 13 is a diagram illustrating a method in which a terminal monitors a preemption indicator based on a pre-specified BWP according to an embodiment of the present invention. [Figure 20] 13 is a diagram illustrating a method for a terminal to monitor a preemption indicator in a CORESET in which a PDCCH for scheduling a PDSCH is transmitted according to an embodiment of the present invention. [Figure 21] FIG. 11 is a diagram showing an example of setting OFDM symbols included in a slot if TDD is used in a wireless communication system according to an embodiment of the present invention. [Figure 22] FIG. 2 is a diagram showing OFDM symbols indicated by a preemption indicator according to an embodiment of the present invention. [Diagram 23] FIG. 2 is a diagram showing OFDM symbols indicated by a preemption indicator according to an embodiment of the present invention. [Figure 24] A diagram showing OFDM symbols indicated by a preemption indicator according to an embodiment of the present invention with respect to reserved resources. [Diagram 25] A diagram showing OFDM symbols indicated by a preemption indicator according to an embodiment of the present invention with respect to reserved resources. [Figure 26] A diagram showing OFDM symbols indicated by a preemption indicator according to an embodiment of the present invention with respect to reserved resources. [Figure 27] 1 is a diagram showing OFDM symbols in which a bitmap of a preemption indicator indicates whether preemption is possible or not according to an embodiment of the present invention. [Figure 28] FIG. 11 is a diagram showing OFDM symbols in which a bitmap of a preemption indicator indicates whether preemption is possible according to another embodiment of the present invention. [Figure 29] FIG. 11 is a diagram showing OFDM symbols in which a preemption indicator bitmap indicates whether preemption is possible according to still another embodiment of the present invention. [Diagram 30] This figure shows that if a terminal according to an embodiment of the present invention is configured to use CA, the terminal monitors a preemption indicator on one of the carriers, which indicates information regarding preemption occurring on another carrier. [Diagram 31] A diagram illustrating an operation method of a base station and a terminal according to an embodiment of the present invention. [Diagram 32] A diagram illustrating an operation method of a base station and a terminal according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The terms used in this specification are selected as common terms currently widely used as much as possible in consideration of the functions in the present invention, but this may vary depending on the intentions, customs, or the emergence of new technologies of the engineers in this field. In addition, in certain cases, the applicant may arbitrarily select some terms, and in this case, the meaning will be described in the description of the relevant invention. Therefore, it is clear that the terms used in this specification should be analyzed based on the substantial meaning of the terms and the contents of this specification as a whole, rather than simply the names of the terms.

[0025] Throughout the specification, when a certain component is "connected" to another component, this includes not only "direct connection" but also "electrical connection" through other components in between. Furthermore, when a certain component is "included" in a certain component, this does not mean excluding other components, but further includes other components, unless otherwise specified to the contrary. In addition, limitations such as "more than" or "less than" based on a specific threshold may be appropriately replaced with "more than" or "less than", respectively, depending on the embodiment.

[0026] The following technologies are used in various wireless access systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. CDMA is implemented in radio technologies such as Universal Terrestrial Radio Access (UTRA) and CDMA2000. TDMA is implemented in radio technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA is implemented in radio technologies such as IEEE802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802-20, Evolved UTRA (E-UTRA), etc. UTRA is a part of the Universal Mobile Telecommunication System (UMTS). 3GPP LTE (Long term evolution) is a part of E-UMTS (Evolved UMTS) using 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 clarity of explanation, the following description will focus on 3GPP NR, but the technical idea of ​​the present invention is not limited thereto.

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

[0028] This application claims priority from Korean Patent Application Nos. 10-2017-0076934 (2017-06-16), 10-2017-0127516 (2017-09-29), 10-2017-0129707 (2017-10-11), 10-2017-0149933 (2017-11-10), 10-2018-0018903 (2018-02-17), and 10-2018-0040134 (2018-04-06), and the examples and descriptions in each of the above applications which are the basis of priority are incorporated herein by reference in their entirety.

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

[0030] FIG. 1 is a diagram illustrating an example of a radio frame structure used in a wireless communication system. Referring to FIG. 1, the radio frame used in the 3GPP NR system is 10 ms (Δf max N f / 100)*T c ) and the radio frame consists of 10 equally sized subframes (SF). Here, Δf max =480*10 3 HZ, N f =4096, T c =1 / (Δf ref *N f、ref ), Δf ref =15*10 3 Hz, N f、ref= 2048. The 10 subframes in one radio frame are numbered from 0 to 9. Each subframe has a length of 1 ms and consists of one or more slots depending on the subcarrier spacing. More specifically, the subcarrier spacing that can be used in the 3GPP NR system is 15*2 μ kHz, and μ is a subcarrier spacing configuration factor, μ=0, 1, 2, 3, 4. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz are used as the subcarrier spacing. One subframe having a length of 1 ms is 2 μ slots, each of which is 2 -μ ms. μ The slots range from 0 to 2 μ The slots in one subframe are numbered from 0 to 10*2. μ The time resources are numbered from -1 to -1. The time resources are divided by at least one of a radio frame number (or a radio frame index), a subframe number (or a subframe number), and a slot number (or a slot index).

[0031] 2 is a diagram illustrating an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system, in particular, a resource grid structure of a 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 period. Unless otherwise specified, an OFDM symbol may simply be referred to as a symbol. Referring to FIG. 2, a signal transmitted from each slot is N size、μ grid、x *N RB SC subcarriers and N slot Symb It is represented by a resource lattice consisting of OFDM symbols, where x=DL for the downlink resource lattice and x=UL for the uplink resource lattice. size、μ grid、x indicates the number of resource blocks (RBs) depending on the subcarrier spacing factor μ (downlink or uplink depending on x), and N slot Symb N denotes the number of OFDM symbols in a slot. RB SC is the number of subcarriers that make up one RB, and N RB SC= 12. Depending on the multiple access method, the OFDM symbol is called a cyclic shift OFDM (CP-OFDM) symbol or a Discrete Fourier transform spreading OFDM (DFT-s-OFDM) symbol. The number of OFDM symbols included in one slot may vary depending on the length of the cyclic prefix (CP). For example, in a normal CP, one slot includes 14 OFDM symbols, while in an extended CP, one slot includes 12 OFDM symbols. In a specific embodiment, the extended CP is used only with a subcarrier spacing of 60 kHz. For convenience of explanation, FIG. 2 illustrates a slot consisting of 14 OFDM symbols, but the embodiment of the present invention is also applicable to slots having a different number of OFDM symbols in the same manner. Referring to FIG. 2, each OFDM symbol is represented by N size、μ grid、x *N RB SC The subcarriers are classified 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] RB is N in the time domain. slot Symb is defined as N (e.g., 14) consecutive OFDM symbols in the frequency domain. RB SC A RB is defined by N (e.g., 12) consecutive subcarriers. 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 SCEach resource element in the resource lattice is uniquely defined by an index pair (k, l) within one slot, where k ranges from 0 to N in the frequency domain. size、μ grid、x *N RB SC is an index given from -1 to l in the time domain from 0 to N slot Symb This is an index up to -1.

[0034] Meanwhile, one RB is mapped to one physical resource block (PRB) and one virtual resource block (VRB). A PRB is N slot Symb A PRB is defined as N consecutive OFDM symbols (e.g., 14 symbols) in the frequency domain. RB SC A PRB is defined by N (e.g., 12) consecutive subcarriers. RB SC *N slot Symb It consists of resource elements.

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

[0036] Each symbol of a radio frame operating in time division duplex (TDD) or unpaired spectrum consists of at least one of downlink symbol (DL symbol), uplink symbol (UL symbol) or flexible symbol. In frequency division duplex (FDD) or paired spectrum, a radio frame operating on a downlink carrier consists of downlink symbols or flexible symbols. A radio frame operating on an uplink carrier consists of uplink symbols or flexible symbols. A downlink symbol allows downlink transmission but not uplink transmission, and an uplink symbol allows uplink transmission but not downlink transmission. Flexible symbols are used for downlink or uplink symbols depending on different signals. Information about the type of each symbol, i.e. whether it is a downlink symbol, uplink symbol or flexible symbol, is configured in cell-specific (or common) RRC signaling. Also, information regarding the type of each symbol is additionally configured in a specific terminal (UE-specific or dedicated) RRC signal. The base station uses a cell-specific RRC signal to notify 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 that is not configured with uplink symbols and downlink symbols is a flexible symbol.If the information on the symbol type is configured in the specific terminal RRC signal, the base station signals whether the flexible symbol is a downlink symbol or an uplink symbol in the cell-specific RRC signal. In this case, the specific terminal RRC signal changes the downlink symbol or uplink symbol configured in 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 in the symbols, N slot symb The number of uplink symbols among the symbols is signaled. In this case, the downlink symbols of the slot are configured consecutively from the first symbol of the slot. Also, the uplink symbols of the slot are configured consecutively up to the last symbol of the slot. In this case, in the slot, a symbol that is not configured as an uplink symbol and a downlink symbol is a flexible symbol. The type of symbols configured by the RRC signal is called a semi-static DL / UL configuration. The flexible symbols of the semi-static DL / UL configuration previously configured by the RRC signal are indicated as downlink symbols, uplink symbols, or flexible symbols by dynamic SFI (slot format information). In this case, the downlink symbols or uplink symbols configured by the RRC signal are not changed to other symbol types. Table 1 shows an example of dynamic SFI indicated by the base station to the terminal. In Table 1, D indicates downlink symbols, U indicates uplink symbols, and X indicates flexible symbols. 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 a physical channel used in a 3GPP system (e.g., NR) and a general signal transmission method using the physical channel. When a terminal is powered on or newly enters a cell, the terminal performs an initial cell search (S301). More specifically, the terminal synchronizes with a base station through the initial cell search. To this end, 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 acquire information such as a cell ID. Then, the terminal receives a Physical Broadcast Channel from the base station to acquire broadcast information within the cell. After completing the initial cell search, the terminal receives a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Shared Channel (PDSCH) according to the information carried on the PDCCH to acquire more specific system information than the system information acquired through the initial cell search (S302). When the terminal first connects to the base station or there is no radio resource for transmitting a signal, the terminal performs a random access procedure to the base station (S303 to S306). To this end, the terminal transmits a specific sequence to a preamble via a physical random access channel (PRACH) (S303 to S305) and receives a response message to the preamble from the base station via a PDCCH and a corresponding PDSCH (S304 and S306). In the case of a contention-based RACH, a contention resolution procedure is additionally performed. After the above procedures, the terminal receives a PDCCH / PDSCH (S307) and transmits a physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) as a general uplink / downlink signal transmission procedure (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. The format of the DCI may vary depending on the purpose of use of the DCI. Control information that the terminal transmits to the base station via the uplink or that the terminal receives from the base station includes downlink / uplink ACK / NACK signals, a Channel Quality Indicator (CQI), a Precoding Matrix Index (PMI), a Rank Indicator (RI), etc. In the case of a 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 of an SS / PBCH block for initial cell connection in a 3GPP NR system. When a terminal is powered on or attempts to connect to a new cell, it acquires time and frequency synchronization with the cell and performs an initial cell search process. In the cell search process, the terminal obtains the physical cell identity N cell IDIn order to do so, the terminal receives a synchronization signal, for example, a PSS and a subsynchronization signal SSS from the base station and synchronizes with the base station. At this time, the terminal acquires information such as a cell identity (ID). The synchronization signal will be described in more detail with reference to FIG. 4(a). The synchronization signal is divided into a PSS and an SSS. The PSS is used to obtain time domain synchronization such as OFDM symbol synchronization, slot synchronization, and / or frequency domain synchronization. The SSS is used to obtain frame synchronization and a 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, 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 starting from 0. In the first OFDM symbol transmitted by the PSS, the base station does not transmit signals on the remaining subcarriers, i.e., subcarriers 0, 1, . . . 55, 183, 184, . . . 239. In the third OFDM symbol transmitted by the SSS, the base station does not transmit signals on subcarriers 48, 49, . . . 55, 183, 184, . . . 191. The base station transmits PBCH signals on the remaining REs in the SS / PBCH block excluding the above signals.

[0040] [Table 2]

[0041] The SS indicates a total of 1008 unique physical layer cell IDs through a combination of three PSSs and 336 SSs. In particular, the physical layer cell IDs are grouped into 336 physical layer cell ID groups, each group including three unique identifiers, such that each physical layer cell ID is part of only one physical layer cell ID group. Thus, the physical layer cell ID N cellID =3N (1) ID +N (2) ID is a number in the range from 0 to 335 that indicates a physical-layer cell-identifier group. (1) ID and a number N from 0 to 2 indicating said physical-layer cell-identifier within a physical-layer cell-identifier group. (2) ID The terminal detects the PSS and identifies one of the three unique physical-layer cell-identifiers. The terminal also detects the SSS and identifies one of the 336 physical-layer cell IDs associated with the physical-layer cell-identifier. The PSS signal is as follows:

[0042]

number

[0043] Where: x(i+7)=(x(i+4)+x(i))mod2 and [x(6) x(5) x(4) x(3) x(2) x(1) x(0)]=[1 1 1 0 1 1 0] The SSS is given by:

[0044]

number

[0045] Where: x0(i+7)=(x0(i+4)+x0(i))mod2 x1(i+7)=(x1(i+1)+x1(i))mod2 and [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] is given by:

[0046] A radio frame having a duration of 10 ms is divided into two half frames having a duration of 5 ms. The slots in each half frame in which the SS / PBCH block is transmitted are described with reference to FIG. 4(b). The slots in which the SS / PBCH block is transmitted are any one of Cases A, B, C, D, and E. In Case A, the subcarrier spacing is 15 kHz, and the start point of the SS / PBCH block is {2, 8}+14*n symbols. In this case, n=0, 1 for carrier frequencies below 3 GHz. In the range from 3 GHz to 6 GHz, n=0, 1, 2, 3. In Case B, the subcarrier spacing is 30 kHz, and the start point of the SS / PBCH block is {4, 8, 16, 20}+28*n. In this case, n=1 for carrier frequencies below 3 GHz. In the range from 3 GHz to 6 GHz, n=0, 1. In case C, the subcarrier spacing is 30 kHz and the start point of the SS / PBCH block is {2, 8}+14*n, where n=0, 1 for carrier frequencies below 3 GHz. For frequencies above 3 GHz and below 6 GHz, n=0, 1, 2, 3. In case D, the subcarrier spacing is 120 kHz and the start point of the SS / PBCH block is {4, 8, 16, 20}+28*n, where n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18 for carrier frequencies above 6 GHz. In case E, the subcarrier spacing is 240 kHz and the start point of the SS / PBCH block is {8, 12, 16, 20, 32, 36, 40, 44}+56*n. In this case, n=0, 1, 2, 3, 5, 6, 7, 8 for carrier frequencies of 6 GHz or higher.

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

[0048] FIG. 6 is a diagram showing a CORESET in which a PDCCH is transmitted in a 3GPP NR system. CORESET is a time-frequency resource in which PDCCH, which is a control signal for a terminal, is transmitted. Referring to FIG. 6, a terminal does not receive all frequency bands and attempt to decode PDCCH, but receives only time-frequency resources defined as CORESET and decodes PDCCH mapped in CORESET. A base station configures one or more CORESETs for each cell in a terminal. A CORESET is composed of up to three consecutive symbols on the time axis. Also, a CORESET is configured consecutively or discontinuously in units of 6 PRBs on the frequency axis. In the embodiment of FIG. 5, CORESET#1 is composed of consecutive PRBs, and CORESET#2 and CORESET#3 are composed of discontinuous PRBs. A CORESET may be located at any symbol in a slot. For example, CORESET#1 in FIG. 5 starts from the first symbol of a slot, CORESET#2 starts from the fifth symbol of a slot, and CORESET#9 starts from the ninth symbol of a slot.

[0049] FIG. 7 is a diagram related to the setting of a PDCCH search space in a 3GPP NR system. In order to transmit a PDCCH to a terminal, at least one search space exists in each CORESET. In the present invention, the search space is a set of all time-frequency resources (hereinafter, PDCCH candidates) in which the PDCCH of the terminal can be transmitted. The search space includes a common search space that 3GPP NR terminals 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 a PDCCH that is set to be commonly searched by all terminals in a cell belonging to the same base station, and the terminal-specific search space is set for each terminal to monitor a PDCCH assigned to each terminal at different search space positions according to the terminal. The terminal-specific search space may be assigned with a partial overlap between terminal search spaces due to a limited control region that may be assigned to the PDCCH. Monitoring the PDCCH includes blind decoding PDCCH candidates in the search space. If the blind decoding is successful, the PDCCH is said to be (successfully) detected / received, and if the blind decoding is unsuccessful, the PDCCH is said to be undetected / unreceived or not successfully detected / received.

[0050] For ease of explanation, a PDCCH scrambled with a group common (GC) RNTI (or common control RNTI, CC-RNTI) already known to transmit uplink scheduling information or downlink scheduling information to one or more terminals is referred to as a (UE) group common (GC) PDCCH or a common PDCCH. Also, a PDCCH scrambled with a terminal-specific RNTI already known by a specific terminal to transmit uplink scheduling information or downlink scheduling information to one specific terminal is referred to as a user-specific (US) PDCCH.

[0051] The PDCCH informs each terminal or a terminal group of at least one of information on resource allocation (DL Grant) of the transmission channels PCH (Paging channel) and DL-SCH (Downlink-shared channel), resource allocation (Uplink Grant) of the UL-SCH, and HARQ information. The base station transmits PCH transport blocks and DL-SCH transport blocks via the PDSCH. The base station transmits data excluding specific control information or specific service data via the PDSCH. In addition, the terminal receives data excluding specific control information or specific service data via the PDSCH.

[0052] The base station transmits information about which terminal (one or more terminals) the PDSCH data is transmitted to and how the corresponding terminal should receive and decode the PDSCH by including it in the PDCCH. For example, assume that a specific PDCCH is CRC masked with RNTI "A", and information about data to be transmitted using radio resource "B" (e.g., frequency location) and DCI format "C", i.e., transmission format information (e.g., transmission block size, modulation method, coding information), is transmitted through a specific subframe. In this case, a terminal in a cell monitors the PDCCH using its own RNTI information, and if there is one or more terminals with RNTI "A", the corresponding terminal receives the PDCCH and receives the PDSCH indicated by "B" and "C" through the received PDCCH information. Table 2 relates to a physical uplink control channel (PUCCH) 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: A response to a PDCCH (indicating DL SPS release) and / or a response to a downlink data packet on a PDSCH. It indicates whether the PDCCH or PDSCH has been successfully received. The HARQ-ACK response includes a positive ACK (simply ACK), a negative ACK (hereinafter, NACK), DTX (Discontinuous Transmission), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ ACK / NACK and ACK / NACK. In general, ACK is expressed as 1, and NACK is expressed as 0.

[0056] -CSI (Channel State Information): Feedback information for a downlink channel. It is generated by a terminal based on CSI-RS (Reference Signal) transmitted by a base station. MIMO (Multiple Input Multiple 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 that carries 1 or 2 bits of HARQ-ACK information. PUCCH format0 is transmitted using 1 or 2 OFDM symbols on the time axis and 1 PRB on the frequency axis. If PUCCH format0 is transmitted using 2 OFDM symbols, the same sequence is transmitted using different PRBs for two symbols. Through this, the terminal obtains frequency diversity gain. More specifically, the terminal bit bits UCI(Mbit =1 or 2) to determine the cyclic shift value m cs Determine the base sequence of length 12 and divide it by the determined value m cs The sequence cyclically shifted by is mapped to 12REs of 1 PRB of 1 OFDM symbol and transmitted. The number of cyclic shifts available to the terminal is 12, and M bit If M = 1, when the terminal transmits UCI0 and UCI1, the terminal sets the difference between the two cyclic shift values ​​to 6. bit If = 2 and the terminal transmits UCI00, UCI01, UCI11, and UCI10, the terminal sets the difference between the four cyclic shift values ​​to 3.

[0059] PUCCH format1 carries 1-bit or 2-bit HARQ-ACK information. PUCCH format1 is transmitted in consecutive OFDM symbols on the time axis and in one PRB on the frequency 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. bit =1 UCI is BPSK modulated. bit =2 UCI is modulated with quadrature phase shift keying (QPSK) to generate complex valued symbol d(0), which is then multiplied with a sequence of length 12 to obtain a signal. The terminal transmits the resulting signal by spreading it with a time-domain orthogonal cover code (OCC) on the even-numbered OFDM symbol to which PUCCH format1 is assigned. For PUCCH format1, the maximum number of different terminals that can be multiplexed onto the same PRB is determined according to the length of the OCC used. The Demodulation RS (DMRS) is spread onto the OCC and mapped onto the resulting OFDM symbol of PUCCH format1.

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

[0061] PUCCH format 3 or PUCCH format 4 carries UCI exceeding 2 bits. PUCCH format 3 or PUCCH format 4 is transmitted via consecutive OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 is one of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14. bit bits UCI(M bit >2) with π / 2-BPSK (Binary Phase Keying) or QPSK to generate complex symbols d(0), , d(M symb The terminal generates a PUCCH format 3 subcarrier (1RB-1-1) for PUCCH format 3. 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 PreDFT-OCC of length-12 so that PUCCH format 4 has a multiplexing capacity of 2 or 4. The terminal performs transmit precoding (or DFT-precoding) on ​​the spread signal, maps it to each RE, and transmits the spread signal.

[0062] In this case, the number of PRBs occupied by PUCCH format2, PUCCH format3, or PUCCH format4 is determined according to the length of UCI transmitted by the terminal and the maximum code rate. If the terminal uses PUCCH format2, the terminal transmits both HARQ-ACK information and CSI information via PUCCH. If the number of PRBs that the terminal can transmit is greater than the maximum number of PRBs that PUCCH format2, PUCCH format3, or PUCCH format4 can use, 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 format1, PUCCH format3, or PUCCH format4 is configured via RRC signaling to indicate frequency hopping within a slot. When frequency hopping is configured, the PRB index for frequency hopping is configured via RRC signaling. If PUCCH format1, PUCCH format3, or PUCCH format4 is transmitted over 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 format1, PUCCH format3, or PUCCH format4 is configured to be repeatedly transmitted in multiple slots. In this case, the number K of slots in which the PUCCH is repeatedly transmitted is configured by an RRC signal. The repeatedly transmitted PUCCH should start from the same OFDM symbol position in each slot and have the same length. If the RRC signal indicates that another OFDM symbol in the slot in which the UE should transmit the PUCCH is a DL symbol, the UE does not transmit the PUCCH in the corresponding slot, but extends it to the next slot for transmission.

[0065] In a 3GPP NR system, a terminal transmits and receives using a bandwidth smaller than or equal to the bandwidth of a carrier (or cell). To this end, the terminal is configured with a Bandwidth part (BWP) consisting of a continuous portion of the carrier's bandwidth. A terminal operating according to TDD or in an unpaired spectrum is configured with up to four DL / UL BWP pairs for one carrier (or cell). The terminal also activates one DL / UL BWP pair. A terminal operating according to FDD or in a paired spectrum is configured with up to four DL BWPs for a downlink carrier (or cell) and up to four UL BWPs for an 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 sample time-frequency resources other than the activated BWP. The activated BWP is called an active BWP.

[0066] The base station uses DCI to indicate that the terminal moves from one BWP to another BWP. The terminal moves from one BWP to another BWP, which indicates that the terminal deactivates the BWP used by the terminal and activates a new BWP. In a carrier (or cell) operating in TDD, the base station includes a BPI (Bandwidth part indicator) indicating the activated BWP in DCI for scheduling PDSCH or PUSCH to change the DL / UL BWP pair of the terminal. The terminal receives the DCI for scheduling PDSCH or PUSCH and identifies the activated DL / UL BWP pair based on the BPI. In the case of a downlink carrier (or cell) operating in FDD, the base station includes a BPI indicating the activated BWP in 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 indicating the activated BWP in DCI for scheduling PDSCH to change the UL BWP of the terminal. The carrier aggregation technique will be described below. Figure 6 is a conceptual diagram illustrating carrier aggregation.

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

[0068] Referring to FIG. 8, as an example of a 3GPP NR system, the entire system band includes a maximum of 16 component carriers, each of which has a maximum bandwidth of 400 MHz. The component carrier includes one or more physically contiguous subcarriers. Although FIG. 8 shows each component carrier having the same bandwidth, this is merely an example, and each component carrier may have a different bandwidth. Also, although each component carrier is shown adjacent to each other on the frequency axis, the figure is shown in a logical external view, and each component carrier may be physically adjacent to each other or separated from each other.

[0069] A different center carrier (conter frequency) is used in each component carrier. Also, a common center carrier is used in physically adjacent component carriers. In the embodiment of FIG. 8, if it is assumed that all component carriers are physically adjacent, center carrier A is used for all component carriers. Also, if it is assumed that each component carrier is not physically adjacent, center carrier A and center carrier B are used for each component carrier.

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

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

[0072] Referring to FIG. 9(a), a general wireless communication system transmits or receives data through one DL band and one corresponding UL band (in the case of frequency division duplex (FDD) mode). In another specific embodiment, the wireless communication system divides a radio frame into an uplink time unit and a downlink time unit in the time domain, and transmits or receives data through the uplink / downlink time unit (in the case of time division duplex (TDD) mode). Referring to FIG. 9(b), three 20 MHz CCs are aggregated in each of the UL and DL to support a bandwidth of 60 MHz. The respective CCs are adjacent or non-adjacent to each other in the frequency domain. Although FIG. 9(b) illustrates a case in which the bandwidth of the UL CC and the bandwidth of the DL CC are the same and symmetrical for convenience, the bandwidth of each CC may be determined independently. Also, asymmetric carrier aggregation in which the number of UL CCs and the number of DL CCs are different is possible. A DL / UL CC assigned to a specific UE via RRC is called a configured serving UL / DL CC in a specific UL.

[0073] The base station activates some or all of the serving CCs configured in the terminal, or deactivates some of the CCs to be used for communication with the terminal. The base station changes the CCs to be activated / deactivated and the number of CCs to be activated / deactivated. When the base station allocates CCs available to the terminal to cell-specific or terminal-specific, at least one of the CCs once allocated is not deactivated unless the CC allocation to the terminal is completely reconfigured or the terminal is handed over. A CC that is not deactivated by the terminal is called a Primary CC (PCC), and a CC that the base station activates / deactivates freely is called a Secondary CC (SCC). PCCs and SCCs may be distinguished based on control information. For example, specific control information is set to be transmitted and received only through a specific CC, and such a specific CC may be called a PCC and the remaining CC(s) may be called SCC(s).

[0074] Meanwhile, 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), i.e., 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 DL resources (or DL ​​CC) and the carrier frequency of UL resources (or UL CC) is indicated by system information. For a UE in RRC_CONNECTED state but with no carrier aggregation configured or that does not support carrier aggregation, there is only one serving cell configured with only a PCell.

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

[0076] Figure 10 is a diagram showing an example in which the cross-carrier scheduling technique is applied. In particular, in Figure 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 (i.e., Primary Cell, PCell), and the remaining component carriers #1 and #2 are secondary component carriers (i.e., Secondary Cell, SCell).

[0077] The present invention proposes an effective management method of uplink resources for a primary component carrier (or Primary Cell or PCell) or a secondary component carrier (or SCell) during carrier aggregation operation of a terminal. In the following, a case where a terminal operates by aggregating two component carriers will be described, but it is obvious that the method can also be applied to a case where three or more component carriers are aggregated.

[0078] 9 to 10 are mainly illustrated with respect to 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] In the following description of the present invention, in order to facilitate understanding, each content will be described separately as an embodiment, but each embodiment may be used in combination with each other.

[0080] FIG. 11 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention. As shown, 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 commands or programs to process data within the terminal 100. The processor 100 also controls the overall operation of the terminal 100 including each unit, 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 slot configuration based thereon, 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 and 122 and a wireless LAN interface card 123, either built-in or external. In the drawings, the communication module 120 is shown as an integrated module, but the network interface cards may be arranged independently depending on the circuit configuration or application, unlike the drawings.

[0083] The cellular communication interface card 121 transmits and receives wireless signals to and from at least one of the base station 200, an external device, and a server through a mobile communication network, and provides a cellular communication service in a first frequency band based on an instruction from the processor 110. Here, the wireless signals include various types of data or information, such as a voice call signal, a video call signal, and / or an email / multimedia message. The cellular communication interface card 121 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 base station 200, an external device, and a server according to a 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 to and from at least one of the base station 200, an external device, and a server through a mobile communication network, and provides a cellular communication service in the second frequency band based on instructions from the processor 110. The cellular communication interface card 122 includes at least one NIC module that uses an LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a 2.4 GHz or 5 GHz band.

[0085] The WLAN interface card 123 transmits and receives wireless signals to and from at least one of the base station 200, the external device, and the server via a WLAN connection, and provides a WLAN service in a second frequency band based on instructions from the processor 110. The WLAN interface card 123 includes at least one NIC module that utilizes a WLAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as the 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, the external device, and the server according to a WLAN standard or protocol of the frequency band supported by the corresponding NIC module.

[0086] Next, the memory 130 stores a control program and various data associated therewith used by the terminal 100. Such a control program includes a predetermined program required 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 types of input / output means provided in the terminal 100. That is, the user interface unit 140 receives user input using various input means, and the processor 110 controls the terminal 100 based on the received user input. Also, the user interface 140 performs output based on a command from the processor 110 using various output means.

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

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

[0090] First, the processor 210 executes various commands or programs to process data within the base station 200. The processor 210 also controls the overall operation of the base station 200 including each unit, and controls 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, either built-in or external. In the drawings, the communication module 220 is shown as an integrated module, but the network interface cards may be arranged independently depending on the circuit configuration or application, unlike the drawings.

[0092] The cellular communication interface card 221 transmits and receives wireless signals to and from at least one of the terminal 100, the external device, and the server using a mobile communication network, and provides a cellular communication service through a first frequency band based on an instruction from the processor 210. Here, the wireless signals include various types of data or information, such as a voice call signal, a video call signal, and / or an e-mail / multimedia message. The cellular communication interface card 221 includes at least one NIC module using 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 a 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 to and from 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 of the processor 210. The cellular communication interface card 222 includes at least one NIC module using 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, the 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 WLAN interface card 223 transmits and receives wireless signals to and from at least one of the terminal 100, an external device, and a server via a WLAN connection, and provides a WLAN service in a second frequency band based on instructions from the processor 210. The WLAN interface card 223 includes at least one NIC module that uses a WLAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as the 2.4 GHz or 5 GHz band. The 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 WLAN standard or protocol of the frequency band supported by the corresponding NIC module.

[0095] The terminal 100 and base station 200 shown in FIG. 11 are block diagrams according to an embodiment of the present invention, and the separate blocks are illustrated to logically distinguish the elements of the devices. Thus, the above-mentioned device elements may be mounted on one chip or multiple chips depending on the design of the device. Also, some components of the terminal 100, such as the user interface 140 and the display unit 150, may be selectively provided in the terminal 100. Also, the user interface 140 and the display unit 150 may be additionally provided in the base station 200 as necessary.

[0096] In this specification, the term "configure" refers to a configuration by a base station. In particular, the base station transmits a channel or a signal to the terminal and configures the operation of the terminal or the value of a parameter used in the wireless 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 a time-frequency resource in which the PDCCH, which is a control signal for the terminal, is transmitted. Also, a search space is mapped to one CORESET. Therefore, the terminal does not monitor all frequency bands to receive the PDCCH, but monitors a time-frequency region designated as the CORESET and decodes the PDCCH mapped to the CORESET.

[0098] In a specific embodiment, there is one CORESET per cell. In this case, a terminal connected to the corresponding cell receives a PDCCH from one CORESET. In another specific embodiment, as shown in FIG. 12, multiple CORESETs may exist in one cell. In this case, a terminal connected to the corresponding cell monitors one or multiple CORESETs. In particular, a terminal connected to a cell is configured by a base station to monitor one or multiple CORESETs. In addition, multiple CORESETs allocated to one terminal are configured to overlap with each other in time-frequency resources.

[0099] The terminal determines the time-frequency region occupied by the CORESET assigned to the terminal by the base station in the current slot. However, the terminal may not be able to determine the time-frequency region occupied by the CORESET not assigned to the terminal by the base station 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 resource occupied by the PDSCH dynamically assigned in the CORESET of a later time slot than the current one assigned to the terminal by the base station.

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

[0101] FIG. 14 is a diagram showing an example of a BWP set in a terminal according to an embodiment of the present invention and a CORESET for the BWP. When multiple BWPs are configured in a terminal, each of multiple CORESETs for each of the multiple BWPs is located in the time-frequency resource region occupied by the corresponding BWP. When multiple BWPs are configured in a terminal, at least one CORESET is configured in the terminal from each of the multiple BWPs. When multiple BWPs are configured to not overlap with each other and when multiple BWPs are configured to overlap with each other, the CORESET for each of the multiple BWPs exists in the PRB occupied by the corresponding BWP. Also, when multiple BWPs are configured to overlap with each other, the PRB occupied by the CORESET for each 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 each other. The first CORESET (CORESET #1) corresponding to the first BWP (Bandwidth part #1) exists in the PRB occupied by the first BWP (Bandwidth part #1). The second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2) exists in the PRB 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 in the PRB 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 PRB occupied by the second BWP (Bandwidth part #2). In this case, the PRB occupied by the second CORESET (CORESET #2) overlaps with the PRB occupied by the first BWP (Bandwidth part #1).

[0103] In order to implement various functions in the NR system, the base station uses a time-frequency resource region scheduled for one terminal for another purpose and indicates that the time-frequency resource region has been used for another purpose. The base station's use of a time-frequency resource region scheduled for one terminal for another purpose is called preemption. A terminal to which the scheduled time-frequency resource is punctured is called an impacted terminal. A terminal to which the time-frequency resource is assigned for another purpose is called a preempting terminal. A base station according to an embodiment of the present invention performs a preemption operation as follows.

[0104] In detail, the base station multiplexes delay-insensitive data and delay-sensitive data for the same or different terminals, and transmits the multiplexed data. The delay-insensitive data is data for the eMBB service described above. The delay-sensitive data is data for the URLLC service described above. The base station schedules the delay-insensitive data on a slot basis. In this case, the base station schedules the delay-sensitive data in a time interval unit having a duration shorter than the duration of the slot. A time interval having a duration shorter than the duration of the slot is called a mini-slot. The number of OFDM symbols assigned to one slot may vary depending on the subcarrier spacing. If 15 kHz is used as the reference subcarrier spacing, one slot includes 7 or 14 OFDM symbols. If 30 kHz is used as the reference subcarrier spacing, one slot includes 14 OFDM symbols. Since the duration of a mini-slot is smaller than the duration of a slot as described above, a mini-slot includes one OFDM symbol less than the number of OFDM symbols included in the slot. In a specific embodiment, the base station schedules delay-sensitive data in units of two OFDM symbols or units of four OFDM symbols. In another specific embodiment, the base station schedules delay-sensitive data in units of seven OFDM symbols in consideration of the duration of the slot. This is because the payload size of delay-insensitive data is relatively large, and the longer the required delay time, the less immediate scheduling is required. Also, the payload size of delay-sensitive data is relatively small, and the shorter the required delay time, the more immediate scheduling is required. In this embodiment, the base station dynamically allocates time-frequency resources for delay-sensitive services and time-frequency resources for non-delay-sensitive services to increase frequency efficiency and reduce delay time. Thus, the base station performs preemption.

[0105] When the base station performs preemption, the impacted terminal scheduled earlier transmits other data through preemption to some of the resources that the terminal is supposed to receive. Therefore, the resources actually transmitted by the base station to the impacted terminal may differ from the data in the resources that the terminal is supposed to receive. The impacted terminal receives and decodes data corrupted by the data transmitted by the base station through preemption. As a result, the terminal's decoding performance may deteriorate, causing a serious degradation in the performance of the impacted terminal. To prevent this, the base station signals the impacted terminal which time-frequency resources have been preempted.

[0106] The terminal decodes data intended to be transmitted from the base station to the terminal based on the signaling for preemption. More specifically, the terminal assumes whether or not data intended to be transmitted from the base station to the terminal is to be transmitted based on the signaling for preemption. In this case, the terminal decodes data received from the base station on a corresponding resource based on a resource for which the base station assumes transmission of data intended to the terminal and a resource for which no data intended to the terminal is to be transmitted. In this case, the data includes at least one of a data channel and a control channel.

[0107] A method of transmitting preemption signaling from a base station to a terminal will be described in detail with reference to Figures 15 to 30. Also, a method of monitoring a group common PDCCH or a terminal specific PDCCH for acquiring a preemption indicator in a terminal will be described in detail with reference to Figures 15 to 20.

[0108] FIG. 15 is a diagram illustrating a method in 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 indicating which time-frequency resource has been preempted to the terminal using a control channel. The preemption indicator described in this specification refers to a DCI format CRC-scrambled with the INT-RNTI. The control channel is the above-mentioned PDCCH. In particular, the control channel is a group common PDCCH or a UE specific PDCCH. If the base station transmits the preemption indicator using the group common PDCCH, the base station scrambles the group common PDCCH to the group common RNTI. In this case, the group common RNTI is a value shared by multiple terminals monitoring the corresponding group common PDCCH. If the preemption indicator is transmitted in a specific-terminal PDCCH, the specific-terminal PDCCH is scrambled to the specific-terminal RNTI, and this specific-terminal RNTI is a value specific to the terminal monitoring the corresponding specific-terminal PDCCH. In a specific embodiment, the terminal applies preemption-related information indicated by a preemption indicator included in the group common PDCCH only to the BWP corresponding to the CORESET in which the PDCCH is transmitted. For example, the terminal may blind decode the group common PDCCH corresponding to a specific BWP to obtain a preemption indicator, and determine whether a data channel or a control channel transmitted from the corresponding BWP is affected by preemption based on the obtained preemption indicator. If the terminal does not need to check whether a data channel or a control channel transmitted from a specific BWP is affected by preemption, the terminal does not need to blind decode the group common PDCCH to obtain a preemption indicator in the CORESET corresponding to the corresponding BWP. In such an embodiment, the terminal can prevent power waste caused 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 FIG. 15(a) and FIG. 15(b), the base station transmits a group-common PDCCH including a preemption indicator signaling 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). It is assumed that the terminal transmits a group common PDCCH or a terminal specific PDCCH including a preemption indicator for signaling information on a preemption operation performed in the first BWP (BW part #1) in a first CORESET (CORESET #1) corresponding to a first BWP (BW part #1). The terminal monitors the group common PDCCH or the terminal specific PDCCH in the first CORESET (CORESET #1) to acquire the preemption indicator for signaling information on a preemption operation performed in the first BWP (BW part #1). In addition, the base station transmits a group common PDCCH or a terminal specific PDCCH including a preemption indicator for signaling information on a preemption operation performed in the second BWP (BW part #2) in a second CORESET (CORESET #2) corresponding to a second BWP (BW part #2). It is assumed that in the second CORESET (CORESET #2) corresponding to the second BWP (BW part #2), the terminal transmits a group common PDCCH or a terminal specific PDCCH including a preemption indicator signaling information regarding the preemption operation performed in the second BWP (BW part #2).The terminal monitors a group common PDCCH or a terminal specific PDCCH in a second CORESET (CORESET #2) to acquire a preemption indicator signaling information about a preemption operation performed in a second BWP (BW part #2).

[0110] In the embodiment of FIG. 15, it has been described that the base station transmits a preemption indicator in the slot next to where preemption occurs. However, the time when the base station transmits the preemption indicator is not limited to the slot next to where preemption occurs. In particular, if preemption occurs in the nth slot (Slot #n), the base station transmits a preemption indicator in the same slot, that is, the nth slot (Slot #n), after preemption occurs. Also, if preemption occurs in the nth slot (Slot #n), the base station may transmit a preemption indicator in the n+1th slot (Slot #n+1) after preemption occurs. If preemption occurs in the nth slot (Slot #n), the base station may transmit a preemption indicator in the n+kth slot (Slot #n+k) after preemption occurs. In this case, k is a natural number equal to or greater than 1. The description regarding the time when the base station transmits the preemption indicator also applies to other embodiments described later, unless otherwise specified.

[0111] FIG. 16 is a diagram illustrating a method in which a UE monitors a preemption indicator based on a CORESET corresponding to a BWP in which a PDSCH is scheduled according to an embodiment of the present invention. The base station transmits a control channel including a preemption indicator signaling information about preemption occurring in the BWP in the CORESET corresponding to the BWP in which the data channel is scheduled. If multiple BWPs are configured in the terminal so that they do not overlap with each other, the terminal assumes that a control channel including a preemption indicator signaling information about preemption occurring in the BWP in which the data channel is scheduled is transmitted from the CORESET corresponding to the BWP. Therefore, if multiple BWPs are configured in the terminal so that they do not overlap with each other, the terminal monitors a control channel in the CORESET corresponding to the BWP in order to obtain a preemption indicator signaling information about preemption occurring in the BWP in which the data channel is scheduled. Also, if multiple BWPs are configured in the terminal so that they do not overlap with each other, the terminal does not need to monitor a control channel in a CORESET other than the CORESET corresponding to the BWP in order to obtain a preemption indicator signaling information about preemption occurring in the BWP in which the data channel is scheduled. In this embodiment, the control channel is a group-common PDCCH or a terminal-specific PDCCH, and 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 configured in 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 in the first BWP (Bandwidth part #1) of the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2). In this case, it is assumed that the group common PDCCH or terminal specific PDCCH including a preemption indicator is transmitted only in the first CORESET (CORESET #1) corresponding to the first BWP (Bandwidth part #1). Therefore, the terminal monitors a group-common PDCCH or a terminal-specific PDCCH in a first CORESET (CORESET #1) to acquire a preemption indicator signaling information on a preemption operation performed in a first BWP (BW part #1). Also, the terminal assumes that a group-common PDCCH or a terminal-specific PDCCH including a preemption indicator signaling information on a preemption operation performed in a first BWP (BW part #1) is transmitted in a second CORESET (CORESET #2) in which a PDSCH is not scheduled. Therefore, even if the terminal is configured to monitor the second CORESET (CORESET #2), the terminal does not need to monitor a group-common PDCCH or a terminal-specific PDCCH to acquire a preemption indicator signaling information on a preemption operation performed in a first BWP (BW part #1) in the second CORESET (CORESET #2).

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

[0114] In the embodiment of FIG. 16(c), the PDSCH is scheduled in the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2), respectively. In this case, the terminal assumes that the group common PDCCH or the terminal specific PDCCH including the preemption indicator is transmitted only in 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 in the first CORESET (CORESET #1) to acquire a preemption indicator that signals information about the preemption operation performed in the first BWP (Bandwidth part #1). In addition, the terminal assumes that the group common PDCCH or the terminal specific PDCCH including the preemption indicator is transmitted only in the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2). Therefore, the terminal monitors a group-common PDCCH or a terminal-specific PDCCH in a second CORESET (CORESET #2) to acquire a preemption indicator that signals information about a preemption operation performed in a second BWP (Bandwidth part #2).

[0115] If multiple BWPs are configured to overlap in a terminal, it may be difficult for the terminal to determine which BWP is scheduled for PDSCH. Therefore, if multiple BWPs are configured to overlap in a terminal, a method is required to determine a CORESET that the terminal monitors to obtain a preemption indicator. This will be described with reference to FIG.

[0116] FIG. 17 illustrates a method for monitoring a preemption indicator based on a CORESET corresponding to a BWP in which a PDSCH is scheduled when multiple BWPs configured in a UE overlap according to an embodiment of the present invention.

[0117] If multiple BWPs set in the terminal overlap, the base station transmits a control channel including a preemption indicator signaling information regarding preemption occurring in the transmission of the corresponding data channel in the CORESET corresponding to the smallest BWP among the BWPs including all frequency domains in which the data channel is scheduled. If multiple BWPs set in the terminal overlap, the terminal assumes that a control channel including a preemption indicator signaling information regarding preemption occurring in the transmission of the corresponding data channel is transmitted from the CORESET corresponding to the smallest BWP among the BWPs including all frequency domains in which the data channel is scheduled. Therefore, if multiple BWPs set in the terminal overlap, the terminal monitors the control channel in the CORESET corresponding to the smallest BWP among the BWPs including all frequency domains in which the data channel is scheduled to obtain a preemption indicator signaling information regarding preemption occurring in the transmission of the corresponding data channel. In addition, if multiple BWPs set in the terminal overlap, the terminal may not monitor the control channel in a CORESET other than the CORESET corresponding to the smallest BWP among all the BWPs including the frequency domain in which the data channel is scheduled in order to obtain a preemption indicator that signals information regarding preemption generated from the transmission of the corresponding data channel. In this embodiment, the control channel is a group common PDCCH or a terminal specific PDCCH. In this 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 configured in the terminal. The second BWP (Bandwidth part #2) includes the first BWP (Bandwidth part #1). For convenience of explanation, a preemption indicator for signaling information regarding preemption for PDSCH transmission is described as a preemption indicator in the embodiment of FIG. 17. In the embodiment of FIG. 17(a), the 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 in which the PDSCH is scheduled, it is assumed that the terminal transmits a group-common PDCCH or a terminal-specific PDCCH that includes a preemption indicator only in the first CORESET (CORESET #1) that corresponds to the first BWP (Bandwidth part #1). Therefore, the terminal monitors a group common PDCCH or a terminal specific PDCCH in the first CORESET (CORESET #1) to acquire a preemption indicator. Also, the terminal assumes that a group common PDCCH or a terminal specific PDCCH including a preemption indicator is not transmitted in a second CORESET (CORESET #2) in which a PDSCH is not scheduled. Therefore, even if the terminal is configured to monitor the second CORESET (CORESET #2), the terminal does not need to monitor the group common PDCCH or the terminal specific PDCCH to acquire a preemption indicator in the second CORESET (CORESET #2).

[0119] In the embodiment of FIG. 17(b), the PDSCH is scheduled in a frequency region that includes only the second BWP (Bandwidth part #2) of 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 that include all the frequency regions in which the PDSCH is scheduled, the terminal assumes that the group common PDCCH or the terminal specific PDCCH including the preemption indicator is transmitted only in the second CORESET (CORESET #2) that corresponds to the second BWP (Bandwidth part #2). Therefore, the terminal monitors the group common PDCCH or the terminal specific PDCCH in the second CORESET (CORESET #2) to acquire the preemption indicator. In addition, the terminal assumes that the group common PDCCH or the terminal specific PDCCH including the preemption indicator is not transmitted in the first CORESET (CORESET #1) in which the PDSCH is not scheduled. Therefore, even if the terminal is configured to monitor the first CORESET (CORESET #1), the terminal does not need to monitor the group-common PDCCH or the terminal-specific PDCCH to acquire a preemption indicator in 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 domain where the PDSCH is scheduled, and the second BWP (Bandwidth part #2) includes the whole frequency domain where the PDSCH is scheduled. Since the first BWP (Bandwidth part #1) does not include the whole frequency domain where the PDSCH is scheduled, and the second BWP (Bandwidth part #2) includes the whole frequency domain where the PDSCH is scheduled, the terminal assumes that the group common PDCCH or terminal specific PDCCH including the preemption indicator is transmitted only in the second CORESET (CORESET #2) corresponding to the second BWP (Bandwidth part #2). Therefore, the terminal monitors the group common PDCCH or the specific terminal PDCCH in the second CORESET (CORESET #2) to acquire the preemption indicator. Also, the UE assumes that a group common PDCCH or a UE specific PDCCH including a preemption indicator is not transmitted in a first CORESET (CORESET #1) in which a PDSCH is not scheduled. Therefore, even if the UE is configured to monitor the first CORESET (CORESET #1), the UE does not need to monitor the group common PDCCH or the UE specific PDCCH to acquire a preemption indicator in the first CORESET (CORESET #1).

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

[0122] As described above, the base station transmits a specific terminal PDCCH or a group common PDCCH including a preemption indicator through a pre-designated BWP regardless of the BWP in which the PDSCH is scheduled. Therefore, it is assumed that the terminal receives a specific terminal PDCCH or a group common PDCCH including a preemption indicator through a pre-designated BWP. The terminal monitors the specific terminal PDCCH or the group common PDCCH including a preemption indicator in the pre-designated BWP 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 configured in 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 in the first BWP (Bandwidth part #1) 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 in the second BWP (Bandwidth part #2) 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 in the first BWP (Bandwidth part #1) and the second BWP (Bandwidth part #2), respectively.

[0124] In the embodiment of FIG. 19, a first BWP (Bandwidth part #1) and a second BWP (Bandwidth part #2) are configured in the terminal. The second BWP (Bandwidth #2) includes the first BWP (Bandwidth part #1). In the embodiment of FIG. 19(a), the PDSCH is scheduled in a frequency region that includes 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 a frequency region that includes only the second BWP (Bandwidth part #2) of 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 the entire frequency region in which the PDSCH is scheduled.

[0125] For convenience of explanation, in the embodiment of Fig. 18 to Fig. 19, a preemption indicator for signaling information on preemption for PDSCH transmission is described as a preemption indicator. In the embodiment of Fig. 18 to Fig. 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 a terminal specific PDCCH or a group common PDCCH including a preemption indicator is transmitted only in a first CORESET (CORESET #1) corresponding to a pre-specified first BWP (Bandwidth part #1). The terminal monitors a specific terminal PDCCH or a group common PDCCH in the first CORESET (CORESET #1) to acquire a preemption indicator. Also, the terminal does not need to monitor a specific terminal PDCCH or a group common PDCCH in the second CORESET (CORESET #2) to acquire a 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 performs blind decoding of the specific terminal PDCCH or the group common PDCCH according to 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 a specific terminal PDCCH or a group common PDCCH including a preemption indicator may vary according to the number of BWPs in which the PDSCH is transmitted. For example, the length of the DCI payload of the PDCCH when the frequency domain 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 the frequency domain in which the PDSCH is transmitted is included in k BWPs. In this case, n and k are both natural numbers, and n is greater than k. In particular, the length of the DCI payload of the PDCCH when the frequency domain 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 the frequency domain in which the PDSCH is transmitted is included in one BWP. According to this embodiment, the base station sets the length of the DCI payload of the PDCCH including a preemption indicator based on the number of BWPs in which the PDSCH is transmitted. According to this embodiment, the terminal also determines the length of the DCI payload of the PDCCH including a preemption indicator based on the number of BWPs in which the PDSCH is transmitted.

[0128] In another specific embodiment, the length of the DCI payload of a specific terminal PDCCH or a group common PDCCH including a preemption indicator may vary depending on the number of PRBs occupied by the PDSCH. In particular, 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. In particular, the length of the DCI payload of the PDCCH including a preemption indicator is ceil(k*X) bits. In this case, k is a number between 0 and 1, and ceil(a) is the smallest natural number that is equal to or larger than a. Unless otherwise specified in this specification, ceil(a) indicates the smallest natural number that is equal to or larger than a. According to this embodiment, the base station sets the length of the DCI payload of the PDCCH including a preemption indicator based on the number of PRBs occupied by the PDSCH. According to this embodiment, the terminal determines the length of the DCI payload of the PDCCH including a preemption indicator based on the number of PRBs occupied by the PDSCH.

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

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

[0131] In a specific embodiment, the base station transmits a control channel including a preemption indicator signaling information regarding preemption occurring in the transmission of the corresponding data channel in a CORESET in which a control channel for scheduling a data channel is transmitted in a frequency domain in which the data channel is scheduled. It is assumed that the control channel including the preemption indicator signaling information regarding preemption occurring in the transmission of the corresponding data channel is transmitted from a CORESET in which a control channel for scheduling a data channel is transmitted in a frequency domain in which the data channel is scheduled. Thus, the terminal monitors the control channel in a CORESET in which a control channel for scheduling a data channel is transmitted in a frequency domain in which the data channel is scheduled in order to obtain a preemption indicator signaling information regarding preemption occurring in the transmission of the corresponding data channel. In addition, the terminal does not need to monitor a control channel in a CORESET other than a CORESET in which a control channel for scheduling a data channel is transmitted in a frequency domain in which the data channel is scheduled in order to obtain a preemption indicator signaling information regarding preemption occurring in the transmission of the corresponding data channel. In some embodiments, the control channel is a group-common PDCCH or a terminal-specific PDCCH, and in some embodiments, 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 configured in the terminal. Also, the second BWP (Bandwidth part #2) includes the first BWP (Bandwidth part #1). In the embodiment of FIG. 20(a), the PDSCH is scheduled in a frequency region that includes 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 a frequency region that includes only the second BWP (Bandwidth part #2) of 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 the entire frequency region in which the PDSCH is scheduled.

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

[0134] A preemption indication method of the preemption indicator will be described in detail with reference to Figures 21 to 30. In order to explain the OFDM symbol for which the preemption indicator indicates whether or not preemption occurs, the OFDM symbol configuration included in the slot will be described first.

[0135] FIG. 21 is a diagram illustrating an example of setting OFDM symbols included in a slot if TDD is used in a wireless communication system according to an embodiment of the present invention. When TDD is used in the wireless communication system according to the embodiment of the present invention, the symbols included in a slot are classified into DL symbols, UL symbols, and flexible symbols. DL symbols are symbols for scheduling DL transmission. UL symbols are symbols for scheduling UL transmission. Flexible symbols are symbols that do not correspond to DL symbols and UL symbols. Flexible symbols are also called unknown symbols. Flexible symbols are also 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 symbol configurations included in one slot. In the embodiment of FIG. 21, one slot includes 14 symbols. Also, in the figure, N DL denotes the number of DL symbols, and N FL denotes the number of flexible symbols, and N UL denotes the number of UL symbols. In the embodiment of Figure 21, any one slot includes 7 DL symbols, 3 flexible symbols, and 4 UL symbols.

[0136] The base station uses the RRC configuration to signal the slot format to the terminal. In this case, the base station uses at least one of a cell-specific RRC signal and a specific terminal RRC signal. In particular, the base station uses the RRC configuration to signal whether each symbol of the slot corresponds to one of DL symbols, UL symbols, and flexible symbols. In particular, the base station uses the RRC configuration to signal a symbol that explicitly corresponds to a DL symbol and a symbol that explicitly corresponds to a UL symbol among a plurality of OFDM symbols included in the slot. In a specific embodiment, the terminal determines a symbol designated as a DL slot and a DL symbol by the cell-specific RRC signal as a DL symbol, determines a symbol designated as a UL slot and a UL symbol by the cell-specific RRC signal as a UL symbol, and determines a symbol designated as a flexible symbol by the cell-specific RRC signal as a flexible symbol. Alternatively, the terminal determines a symbol that is not designated as a DL slot and a DL symbol and is not designated as a UL slot and a UL symbol by the cell-specific RRC signal as a flexible symbol.

[0137] Also, the base station signals that the remaining symbols, excluding the symbols corresponding to DL symbols and UL symbols, among the multiple OFDM symbols included in the slot, correspond to flexible symbols. Therefore, the terminal determines the symbols included in the slot as one of DL symbols, UL symbols, and flexible symbols based on the RRC configuration. In detail, the terminal determines the symbols designated as DL symbols by the RRC configuration as DL symbols, and determines the symbols designated as UL symbols by the RRC configuration as UL symbols. Also, the terminal determines the symbols not designated as DL symbols or UL symbols by the RRC configuration as flexible symbols. In a specific embodiment, the terminal determines the symbols designated as DL symbols by a cell-specific RRC signal as DL symbols, determines the symbols designated as UL symbols by the cell-specific RRC signal as UL symbols, and determines the symbols not designated as DL symbols or UL symbols by the cell-specific RRC signal as flexible symbols. In this case, the base station sets the flexible symbols using a specific terminal RRC signal. Therefore, the terminal determines whether the OFDM symbol designated as a flexible symbol by the cell-specific RRC signal is a DL symbol, a UL symbol, or a flexible symbol based on the specific terminal RRC signal. In particular, if the specific terminal RRC signal designates the OFDM symbol designated as a flexible symbol by the cell-specific RRC signal as a DL symbol, the terminal determines the corresponding OFDM symbol as a DL symbol. Also, if the specific terminal RRC signal designates the OFDM symbol designated as a flexible symbol by the cell-specific RRC signal as a UL symbol, the terminal determines the corresponding OFDM symbol as a UL symbol. Also, if the specific terminal RRC signal does not designate the OFDM symbol designated as a 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 specific terminal RRC signal designates the OFDM symbol designated as a flexible symbol by the cell-specific RRC signal as a flexible symbol, the terminal determines the corresponding OFDM symbol as a flexible symbol.

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

[0139] In addition, if the additional signaling other than the RRC configuration does not specify the flexible symbol as a DL symbol or a UL symbol, the terminal transmits to the base station using the flexible symbol or does not assume reception from the base station. If the additional signaling other than the RRC configuration specifies the flexible symbol as a DL symbol or a UL symbol, the terminal assumes the flexible symbol is a DL symbol or a UL symbol as specified by the additional signaling. Therefore, if the additional signaling specifies that the flexible symbol is a DL symbol, the terminal assumes reception from the base station using the corresponding symbol. In addition, if the additional signaling specifies that the flexible symbol is a UL symbol, the terminal transmits to the base station using the corresponding symbol.

[0140] In addition, in this specification, unless otherwise specified, the RRC signal for slot configuration indicates a cell-specific RRC signal in system information. The base station names the cell-specific RRC signal Slot-assignmnetSIB1. Also, the terminal-specific RRC signal names the Slot-assignmnet. FIG. 22 is a diagram illustrating an OFDM symbol indicated by a 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. In addition, the base station transmits a control channel including a preemption indicator for one or more slots. The terminal monitors the control channel including a preemption indicator for one or more slots. In this case, the terminal determines a period of the CORESET for monitoring the preemption indicator based on the RRC signal. The duration of the reference DL resource is determined by a period during which the base station transmits a control channel including a preemption indicator. In addition, the duration of the reference DL resource is determined by a period during which the terminal monitors the control channel including a preemption indicator.

[0142] If the terminal monitors a control channel including a preemption indicator every x slots, the preemption indicator acquired by the terminal from the control channel transmitted from the nth slot indicates information regarding preemption occurring from the nxth slot, the n-x+1th slot, ..., the n-1th slot. Therefore, if the terminal acquires a preemption indicator from the control channel transmitted from the nth slot, the terminal determines preemption occurring from the nxth slot, the n-x+1th slot, ..., the n-1th slot based on the acquired preemption indicator. The time period corresponding to the reference DL resource is from the next symbol of the CORESET where the control channel including the preemption indicator immediately before the corresponding preemption indicator is received to the last symbol of the CORESET where the control channel including the corresponding preemption indicator is received. Alternatively, the time interval corresponding to the reference DL resource indicates the period from the start symbol of the CORESET configured to monitor a control channel including a preemption indicator immediately before the received preemption indicator to just 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 a preemption indicator instructing preemption generated from the reference DL resource is transmitted. In another specific embodiment, the frequency band corresponding to the reference DL resource is a specific frequency band indicated by the RRC configuration of the base station. In this case, the specific frequency band is a contiguous frequency band. In a specific embodiment, the specific frequency band is a non-contiguous frequency band.

[0144] In addition, the preemption indicator indicates a preempted (or punctured) resource in the time domain and the frequency domain, and includes information indicating a preempted (or punctured) resource in the frequency domain.

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

[0146] The preemption indicator includes information on which of the DL resources allocated to a specific terminal has been preempted. Therefore, the preemption indicator includes information required for a terminal to which DL resources have been allocated. In addition, a terminal to which UL resources have been allocated needs to monitor the preemption indicator. The preemption indicator indicates information on the remaining OFDM symbols excluding some symbols among the OFDM symbols included in the slot corresponding to the preemption indicator. This will be described with reference to Figures 23 to 26.

[0147] FIG. 23 is a diagram illustrating an OFDM symbol indicated by a preemption indicator according to an embodiment of the present invention. Some symbols are determined by an RRC signal indicating the use of the corresponding symbol. In particular, the preemption indicator indicates only information about 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 determines the OFDM symbols for which the preemption indicator indicates information about preemption according to the following embodiment.

[0148] In a specific embodiment, the base station explicitly indicates the reference DL resource corresponding to the preemption indicator using the RRC configuration. It is assumed that the terminal performs preemption only in the OFDM symbol that the RRC configuration indicates for the DL slot and DL symbol. It is also assumed that the terminal indicates information regarding preemption generated from the OFDM symbol that the preemption indicator indicates in 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 the RRC signal. At this time, each bit of the bitmap indicates whether the OFDM symbol corresponding to each bit corresponds to the 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 the RRC signal to indicate the OFDM symbol corresponding to the reference DL resource. The terminal obtains a bitmap from the RRC signal and determines the OFDM symbol that corresponds to the reference DL resource.

[0149] In another specific embodiment, the terminal determines the OFDM symbol corresponding to the reference DL resource based on the slot format set in the RRC signal. Specifically, the terminal determines that the OFDM symbol set as the UL symbol by the RRC configuration is not included in the reference DL resource. This is because the terminal always assumes that the OFDM symbol set as the UL symbol by the RRC configuration is a UL symbol. The terminal assumes that the base station does not preempt the OFDM symbol set as the UL symbol by the RRC configuration. In a specific embodiment, the terminal determines that the reference DL resource includes only the new symbols indicated as DL symbols or flexible symbols in the RRC configuration. Specifically, the base station sets the remaining OFDM symbols, excluding the OFDM symbol set as the UL symbol by the RRC signal, among the OFDM symbols within the preemption indicator transmission period, as the reference DL resource. In this case, the base station sets a preemption indicator based on information on preemption for the corresponding reference DL resource, and signals the preemption indicator to the terminal via a control channel. Also, the terminal determines that the OFDM symbol set as the UL symbol by the RRC signal is not included in the reference DL resource. The terminal determines, among the OFDM symbols during the preemption indicator monitoring period, the OFDM symbol set as the DL symbol by the RRC signal and the symbol set as the flexible symbol by the RRC signal as the reference DL resource. 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. In this case, 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 resource.

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

[0151] In this embodiment, the RRC signal may include not only a cell-specific RRC signal but also a specific terminal RRC signal. Therefore, 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 terminal-specific RRC signal are not included in the reference DL resource. The terminal determines 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 terminal-specific RRC signal, among the OFDM symbols during the preemption indicator monitoring period, as the reference DL resource. If the terminal does not receive a specific terminal RRC signal or the corresponding specific terminal RRC signal is not configured in 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 consecutively located before the UL symbol in the reference DL resource. In particular, the base station sets the remaining OFDM symbols, excluding the OFDM symbols set as UL symbols by the RRC signal among the OFDM symbols in the preemption indicator transmission period, and the n flexible symbols consecutively located immediately before the OFDM symbols set as UL symbols by the RRC signal, as the reference DL resource, and sets the preemption indicator based on the preemption information for the corresponding reference DL resource. In this case, the base station signals the preemption indicator to the terminal via a control channel. This is because a time interval (gap) is required for base change between DL transmission and UL transmission, and therefore there may be flexible symbols that cannot be used for UL transmission or DL ​​transmission. In particular, the n flexible symbols consecutively located immediately before the UL symbol may fall into a guard period for DL-UL switching, or may potentially be assigned to UL symbols, but may not potentially be assigned to DL symbols. Also, the terminal determines that the OFDM symbol set as the UL symbol by the RRC signal and the n flexible symbols consecutively 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 that the OFDM symbol set as the DL symbol by the RRC signal and the n flexible symbols consecutively located immediately before the UL symbol are included in the reference DL resource from among the OFDM symbols during the preemption indicator monitoring period, except for the n symbols set as the flexible symbol by the RRC signal and consecutively located immediately before the UL symbol. In this case, n is 1. Also, n is 2 or more. Also, the base station signals the value of n using the RRC signal. In this case, 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 a cell-specific RRC signal and does not include a specific terminal RRC signal.In another specific embodiment, in "OFDM symbols set as UL symbols by an RRC signal among OFDM symbols within a preemption indicator transmission period", the RRC signal includes both a cell-specific RRC signal and a terminal-specific RRC signal.

[0153] The NR system reserves some resources for forward compatibility or backward compatibility. Such resources are called reserved resources. The reserved resources are used for DL ​​transmission or UL transmission. Therefore, the reference DL resource is set taking the reserved resources into consideration. This will be described with reference to Figures 24 to 26.

[0154] 24 to 26 are diagrams illustrating OFDM symbols indicated by preemption indicators according to embodiments of the present invention with respect to reserved resources. In the above embodiment, the terminal excludes symbols mapped to reserved resources from the reference DL resource, specifically, the terminal excludes OFDM symbols in which all PRBs of the OFDM symbol are set as reserved resources from the reference DL resource.

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

[0156] In another specific embodiment, the terminal excludes symbols mapped to the reserved resources from the reference DL resources based on the frequency domain to which the reserved resources are mapped. In particular, the reference DL resources are divided in the frequency domain according to the frequency domain granularity used in the preemption indicator. If the reference DL resources are divided in the frequency domain, the terminal excludes Of, in which all PRBs are set as reserved resources according to the divided frequency domain, from the reference DL resources.

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

[0158] In another specific embodiment, the terminal determines that the OFDM symbol is the reference DL resource regardless of whether all the PRBs of the OFDM symbol are set as reserved resources. In particular, the terminal excludes the OFDM symbol set as the reserved resource from the reference DL resource. The PRB set as the reserved resource is set by a cell-specific RRC signal.

[0159] In a 3GPP NR system, a terminal uses a PRACH to perform random access. The terminal determines a reference DL resource in relation to a PRACH transmission. The following description will describe a method for a terminal to determine a reference DL resource in relation to a PRACH transmission.

[0160] The PRACH for the terminal is configured by the base station. The terminal acquires information on the PRACH configuration for the terminal from remaining minimum system information (RMSI). The information on the PRACH configuration includes information on the PRACH transmission parameter configuration. In particular, the information on the PRACH transmission parameter configuration includes at least one of a PRACH preamble format configuration, a time resource configuration in which the PRACH is transmitted, and a frequency resource configuration in which the PRACH is transmitted. In addition, the information on the PRACH configuration includes information on the configuration of a root sequence and a cyclic shift value of the PRACH preamble.

[0161] In addition, the condition for the terminal to transmit the PRACH may differ depending on whether the terminal transmits the PRACH from a carrier (or cell) having a frequency band of 60 GHz or more. A carrier using a frequency band of 60 GHz or less is called an FR1 carrier, and a carrier using a frequency band of 60 GHz or more is called an FR2 carrier. A terminal configured with a semi-static DL / UL configuration transmits the PRACH only from UL symbols in the FR1 carrier (or cell). If the time resource configuration of the PRACH overlaps with the DL symbol or the flexible symbol, the terminal configured with the semi-static DL / UL configuration cannot transmit the corresponding PRACH from the FR1 carrier (or cell). A terminal configured with a semi-static DL / UL configuration transmits the PRACH only from UL symbols and flexible symbols in the FR2 carrier (or cell). If the time resource configuration of the PRACH overlaps with the DL symbol, the terminal configured with the semi-static DL / UL configuration cannot transmit the corresponding PRACH from the FR1 carrier (or cell). Also, if the PRACH exists before the SS / PBCH block in the FR2 carrier (or cell), the terminal cannot transmit the PRACH.

[0162] In 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 in the PRACH transmission. In this case, the terminal acquires information on the OFDM symbol configured in the PRACH transmission based on the above-mentioned RMSI. In particular, the terminal acquires PRACHConfigurationIndex, which is a cell-specific RRC signal, from the RMSI.

[0163] In another specific embodiment, 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 in the PRACH transmission. In this case, the terminal obtains information on the OFDM symbol configured in the PRACH transmission based on the above-mentioned RMSI. In particular, the terminal obtains PRACHConfigurationIndex, which is a cell-specific RRC signal, from the RMSI.

[0164] In a 3GPP NR system, information required for a terminal to receive an SS / PBCH block is set by a base station. The terminal determines a reference DL resource associated with the SS / PBCH block. The following description will describe how the terminal determines a reference DL resource associated with the SS / PBCH block.

[0165] The information required to receive the SS / PBCH block is set by a cell-specific RRC signal. More specifically, the information required to receive the SS / PBCH block is set by SSB-transmitted-SIB1 of the cell-specific RRC signal. Also, the information required to receive the SS / PBCH block is set by a specific terminal RRC signal. More specifically, the information required to receive the SS / PBCH block is set by SSB-transmitted of the specific terminal RRC signal. If the terminal cannot acquire the information required to receive the SS / PBCH block from the cell-specific RRC signal and the specific terminal RRC signal, the terminal monitors a predetermined SS / PBCH block. If the terminal acquires SSB-transmitted-SIB1 but cannot acquire SSB-transmitted, the terminal monitors the SS / PBCH block set in SSB-transmitted-SIB1. If the terminal acquires SSB-transmitted, the terminal monitors the SS / PBCH block set in SSB-transmitted.

[0166] The terminal adds the OFDM symbol set as the DL SS / PBCH block to the reference DL resource. As described above, the symbol set as the DL SS / PBCH block is set by at least one of the cell-specific RRC signal SSB-transmitted-SIB1 and the specific terminal RRC signal SSB-transmitted. In more detail, the terminal adds the symbol set as 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 is not set as an SS / PBCH block but does not include an OFDM symbol set as an UL symbol by a cell-specific RRC signal. The terminal determines that the OFDM symbol set as an SS / PBCH block is a reference DL resource among the OFDM symbols during a preemption monitoring period, the DL symbol set by the cell-specific RRC signal, the flexible symbol set by the cell-specific RRC signal, and the UL symbol set by the cell-specific RRC signal.

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

[0169] In this embodiment, the terminal determines that the reference DL resource is not set as the SS / PBCH block but does not include a symbol set as the PRACH. In particular, the terminal determines that the reference DL resource includes the DL symbol set by the cell-specific RRC signal, the flexible symbol set by the cell-specific RRC signal except for the OFDM symbol set as the 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 set by the RRC signal overlaps with the OFDM symbol set as the PRACH, the terminal regards the corresponding OFDM symbol as the DL symbol. Thus, if the OFDM symbol set as the SS / PBCH block set by the RRC signal overlaps with the OFDM symbol set as the PRACH, the terminal determines that the reference DL resource includes the corresponding OFDM symbol.

[0170] In the above embodiment, the terminal determines the DL resource based on the OFDM symbol for "actual PRACH transmission" that is not the OFDM symbol configured as PRACH. In particular, the terminal determines that the reference DL resource does not include the OFDM symbol configured as the OFDM symbol for actual PRACH transmission while not configured as the SS / PBCH block. In a specific embodiment, the terminal determines the DL symbol configured by the cell-specific RRC signal, the flexible symbol configured by the cell-specific RRC signal except for the OFDM symbol configured for actual PRACH transmission, and the OFDM symbol configured as the SS / PBCH block as the reference DL resource among the OFDM symbols during the preemption monitoring period.

[0171] In the above three embodiments, it is described that the terminal determines the reference DL resource in FR2, but the terminal may determine the reference DL resource not only in FR2 but also in FR1 according to the above three embodiments.

[0172] The base station signals a reference DL resource for each preemption indicator using a preemption indicator monitoring period and an offset. The terminal determines a reference DL resource for each preemption indicator based on the preemption indicator monitoring period and offset. In particular, the terminal determines an index of an OFDM symbol corresponding to the reference DL resource using the following formula: {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.offset is the offset. The offsets are 0, 14, and T INT The offset can be one of the following values: Also, the offset is configured by the RRC signal.

[0174] If the preemption indicator indicates whether preemption has occurred for one OFDM symbol per bit, the overhead of the preemption indicator may become excessively large. In a specific embodiment, it is assumed that a slot includes 14 OFDM symbols, and the preemption indicator indicates whether preemption has occurred for the OFDM symbols included in four slots. In this case, if the preemption indicator indicates whether preemption has occurred for one OFDM symbol per bit, the preemption indicator should use a total of 56 bits. The base station sets the preemption indicator such that one bit of the preemption indicator indicates whether preemption has occurred for one or more OFDM symbols. For example, one bit of the preemption indicator may indicate whether preemption has occurred for four OFDM symbols. Assuming that a slot includes 14 OFDM symbols and the preemption indicator indicates whether preemption has occurred in the OFDM symbols included in four slots, the preemption indicator requires 14 bits. The preemption indicator divides all OFDM symbols corresponding to the reference DL resource into a plurality of groups, each of which indicates one or more OFDM symbols, and indicates whether preemption has occurred in each group with one bit. In this case, 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 preemption 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 preemption indicator. A method of dividing all OFDM symbols corresponding to the reference DL resource into a plurality of groups, each of which indicates one or more OFDM symbols, using the preemption indicator will be described with reference to FIG. 27 to FIG. 29.

[0175] FIG. 27 is a diagram illustrating OFDM symbols in which a bitmap of a preemption indicator indicates whether preemption is possible or not according to an embodiment of the present invention. When the reference DL resource includes S OFDM symbols and the preemption indicator has a length of N bits, the S OFDM symbols are divided into N groups, and a method of indicating preemption for the S OFDM symbols by N bits is described. In this case, the terminal determines whether transmission from the base station to the terminal has occurred in all OFDM symbols belonging to the group corresponding to the corresponding bit according to the value of each bit of the N bits of the preemption indicator. In particular, if any one bit of the N bits of the preemption indicator is a first value, the terminal determines that transmission from the base station to the terminal has occurred in all one or more OFDM symbols belonging to the group corresponding to the corresponding bit. Also, if any one bit of the N bits of the preemption indicator is a second value, the terminal determines that transmission from the base station to the terminal has not occurred in all one or more OFDM symbols belonging to the group corresponding to the corresponding bit. Therefore, the terminal additionally receives a preemption indicator in the scheduled resource from the base station, and performs decoding on the resource scheduled from the base station depending on whether transmission from the base station to the terminal has occurred due to preemption. In particular, the terminal determines that transmission from the base station to the terminal has occurred in the OFDM symbol 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 resource. Also, the terminal determines that transmission from the base station to the terminal has not occurred due to preemption in all OFDM symbols of the 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 resource.

[0176] When the preemption indicator includes a bitmap indicating whether or not the OFDM symbol group corresponding to each bit is preempted, the base station uses an RRC signal to explicitly signal the index of the OFDM symbol indicated by each bit of the bitmap. The terminal obtains the index of the OFDM symbol indicated by each bit of the bitmap included in the preemption indicator based on the RRC signal. In another specific embodiment, the terminal determines the OFDM symbol indicated by each bit of the bitmap included in the preemption indicator according to a prespecified rule.

[0177] In addition, the base station divides S OFDM symbols into N groups according to the following method and indicates whether preemption is possible for each of the N groups. In this case, the terminal determines whether preemption is possible for each of the N groups based on the preemption indicator. In this case, the S OFDM symbols corresponding to the DL reference resource are grouped into N groups of C symbols in time order. In this case, C is determined by the following formula. C=ceil(S / N)

[0178] If the S OFDM symbols are displayed as indexed in time order from 1 to N, the N OFDM symbols can be shown to be grouped as follows: the first group is {1, 2, ..., C}, the second group is {C+1, C+2, ..., 2*C}, ..., the N-1th group is {(N-2)*C+1, (N-2)*C+2, ..., (N-1)*C}, and the Nth group is {(N-1)*C, (N-1)*C+1, ..., S}.

[0179] In another specific embodiment, the difference between the number of OFDM symbols contained in each group is at most 1. Of the N groups, the mod(S,N) group contains ceil(S / N) OFDM symbols, and the remaining (N-mod(S,N)) group contains floor(S / N) OFDM symbols. In this case, mod(a,b) indicates the remainder when a is divided by b. In this specification, unless otherwise specified, mod(a,b) indicates the remainder when a is divided by b. Floor(x) indicates the largest integer that is equal to or smaller than x. In this specification, unless otherwise specified, floor(x) indicates the largest integer that is equal to or smaller than x.

[0180] As described above, the OFDM symbols included in the reference DL resource are consecutive. In this case, the S OFDM symbols included in the reference DL resource are indexed in time order as if they were consecutive, and the S OFDM symbols are divided into N groups according to the above two embodiments. However, in such an embodiment, a plurality of non-consecutive OFDM symbols are classified into one group. Also, the probability that a plurality of non-consecutive OFDM symbols are simultaneously punctured by preemption is low. Nevertheless, whether or not preemption is possible is signaled for one group.

[0181] In another embodiment, the S OFDM symbols included in the reference DL resource are grouped into N groups each including consecutive OFDM symbols. In particular, each group only includes consecutive OFDM symbols. For convenience of explanation, the number of OFDM symbols included in each group is denoted as S1, S2, ..., S M The number of bits of the preemption indicator for each group is expressed as N1, N2, ..., N M In this case, N1+N2+…+N M=N. The number of bits of the preemption indicator for each group is determined based on the number of OFDM symbols each group contains. In particular, the number of bits of the preemption indicator for each group is proportional to the number of OFDM symbols each group contains. In particular, for the remaining groups except the last group, the number of bits of the preemption indicator for each group is determined by the following formula: N i =round(NM)*S i / S)+1 In this case, i indicates the index of each group. Also, round(x) indicates the integer closest to x. In this specification, unless otherwise specified, round(x) indicates the integer closest to x. Also, round(x) may be changed to floor(x) indicating a descending operation or ceil(x) indicating an ascending operation. For the last group, the following formula determines the number of preemption indicator bits for the last group: N M =N-(N1+N2+…+N M-1 ).

[0182] In another embodiment, for the remaining groups except the last group, the number of bits of the preemption indicator for each group is determined by the following formula: N i =round(N*S i / S) In this case, 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 descending operation or ceil(x) indicating an ascending operation. The number of bits in the last group of preemption indicators is determined by the following formula: N M =N-(N1+N2+…+N M-1 ).

[0183] In the above embodiment, each group includes consecutive OFDM symbols. However, OFDM symbols included in different slots are included in one group. For example, the last OFDM symbol in the n-3th slot and the first OFDM symbol in the n-2th slot are included in one group. Different transport blocks (TB) are assigned to the 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 regard the OFDM symbols included in different slots as discontinuous in relation to the grouping of the preemption indicator.

[0184] In the above embodiment, the order of group indexes is determined according to the time order of the OFDM symbols contained in the group. Thus, the first group is located at the earliest position in the reference DL resource and includes S1 consecutive OFDM symbols. The last group is located at the latest position in the reference DL resource and includes S1 consecutive OFDM symbols. M OFDM symbols. In another specific embodiment, the order of group indexes is determined in ascending order in the time order of OFDM symbols included in each group. Thus, the first group includes the smallest number of OFDM symbols, and the last group includes the largest number of OFDM symbols. In another specific embodiment, the order of group indexes is determined in descending order in the time order of OFDM symbols included in each group. Thus, 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 earlier group includes the OFDM symbol located earlier in the time domain. Some of the above-mentioned 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. Thus, the preemption indicator transmitted from the n-th slot indicates whether DL resources are punctured by preemption from the n-2-th slot and the n-1-th slot. In FIG. 27, if the preemption indicator corresponds to the first type (Type #1), the preemption indicator indicates all OFDM symbols including the slot. Thus, the preemption indicator divides a total of 28 OFDM symbols into N groups, and the difference in the number of OFDM symbols included in each group is allowed to be only one. If N is 4, the preemption indicator indicates 4 groups including 7 OFDM symbols. In this case, 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-2th slot has been punctured by preemption. 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-2th slot has been punctured by preemption. 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-1th slot has been punctured by preemption. Also, the fourth bit of the preemption indicator indicates whether at least one of the OFDM symbols from the 8th OFDM symbol to the 14th OFDM symbol in the n-1th slot is punctured by preemption, since the 8th OFDM symbol to the 14th OFDM symbol in the n-1th slot 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 the second type (Type #2) or the third type (Type #3), the preemption indicator indicates only OFDM symbols that can be preempted among the OFDM symbols included in the slot. In this case, the terminal determines the reference DL resource based on the setting of the OFDM symbols included in the slot and the RRC signal. The first OFDM symbol to the tenth OFDM symbol of the n-2th slot and the first OFDM symbol to the second 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 the second type (Type #2), multiple OFDM symbols that correspond to the reference DL resource are grouped regardless of whether the OFDM symbols included in one group are consecutive. In addition, the difference in the number of OFDM symbols included in each group is at most one. In particular, the 12 OFDM symbols indicate four groups each including three OFDM symbols. In detail, the first bit of the preemption indicator bitmap indicates whether at least one of the OFDM symbols from the first OFDM symbol to the third OFDM symbol in the n-2th slot has been punctured by preemption, the second bit of the preemption indicator bitmap indicates whether at least one of the OFDM symbols from the fourth OFDM symbol to the sixth OFDM symbol in the n-2th slot has been punctured by preemption, and the third bit of the preemption indicator bitmap indicates whether at least one of the OFDM symbols from the seventh OFDM symbol to the ninth OFDM symbol in 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 tenth OFDM symbol of the n-2th slot and the first OFDM symbol of the n-1th slot to the second OFDM symbol of the n-1th slot is punctured by preemption. In the embodiment of FIG. 27, if the preemption indicator corresponds to the second type (Type #2), the preemption indicator does not indicate unnecessary information, unlike the case where the preemption indicator corresponds to the first type (Type #1). However, the fourth group includes OFDM symbols included in different slots. Therefore, the preemption indicator indicates whether or not the OFDM symbols included in different slots are preempted with one bit. This second type (Type #2) method transmits a preemption indicator for resources that may actually be preempted, thereby preventing a decrease in transmission rate that occurs when a terminal decodes and combines resources that may not be unnecessarily preempted under the assumption that no transmission will occur from the base station.

[0187] If the preemption indicator is of the third type (Type #3), a plurality of OFDM symbols corresponding to the reference DL resource are grouped on the premise that all OFDM symbols included in one group are consecutive. In the embodiment of FIG. 27, they are divided into 10 consecutive OFDM symbols and 2 OFDM symbols. In this case, the number of bits (N1) of the preemption indicator indicating 10 consecutive OFDM symbols is obtained according to the following formula: N1=round((N-2)*S1 / S)+1 In this case, S is the total number of OFDM symbols corresponding to DL reference resources. S1 is the number of first consecutive OFDM symbols. N is the total number of bits of the preemption indicator. Therefore, if the preemption 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. In detail, the first bit of the preemption indicator bitmap indicates whether at least one of the OFDM symbols from the first OFDM symbol to the fourth OFDM symbol of the n-2th slot is punctured by preemption. The second bit of the preemption indicator bitmap indicates whether at least one of the OFDM symbols from the fifth OFDM symbol to the seventh OFDM symbol of the n-2th slot is punctured by preemption. Also, the third bit of the preemption indicator bitmap indicates whether at least one of the OFDM symbols from the 8th OFDM symbol to the 10th OFDM symbol of the n-2th slot is punctured by preemption. Also, the fourth bit of the preemption indicator bitmap indicates whether at least one of the OFDM symbols from the 1st OFDM symbol of the n-1th slot to the 2nd OFDM symbol of the n-1th slot is punctured by preemption. If the preemption indicator corresponds to the third type (Type #3), unlike the case where the preemption indicator corresponds to the second type (Type #2), OFDM symbols included in different slots are not indicated in one bit. This second type (Type #3) method transmits a preemption indicator for resources that may actually be preempted, thereby preventing a decrease in transmission rate that occurs when a terminal decodes and combines resources that may not be unnecessarily preempted under the assumption that no transmission will occur from the base station.In addition, when transmissions for TB occur simultaneously in different slots, the possibility of non-consecutive preemption occurring in different slots is low. Therefore, when the base station uses this embodiment, it can more accurately indicate to the terminal the resources that may be preempted.

[0188] FIG. 28 is a diagram illustrating OFDM symbols in which a bitmap of a preemption indicator indicates whether preemption is possible according to another embodiment of the present invention. In another specific embodiment of the present invention, the base station divides the reference DL resource into a plurality of sub-reference DL resources, divides the sub-reference DL resource into a plurality of groups, and indicates whether preemption is possible. In particular, the preemption indicator indicates one of the sub-reference DL resources included in the reference DL resource, and indicates whether preemption is possible for each of the plurality of groups including the sub-reference DL resource. In this case, the preemption indicator includes a first field indicating one of the plurality of sub-reference DL resources, and a second field indicating whether preemption is possible for the plurality of groups included in the indicated sub-reference DL resource. In this case, the second field is set according to the method of setting the bitmap of the preemption indicator described in the above embodiment. The terminal determines the sub-reference DL resource indicated by the preemption indicator based on the preemption indicator, and determines whether preemption is possible for the plurality of groups included in the sub-reference DL resource based on the preemption indicator. In detail, the terminal determines the sub-reference DL resource indicated by the preemption indicator based on the first field, and determines whether to preempt a plurality of groups included in the sub-reference DL resource based on the second field. The sub-reference DL resource includes a designated number of OFDM symbols. In this case, the designated number is the number of OFDM symbols included in one slot. In addition, the sub-reference DL resource is limited to include only consecutive OFDM symbols.

[0189] In the embodiment of FIG. 28, the first bit of the preemption indicator indicates the sub-reference DL resource in which preemption has occurred, and the second bit is a bitmap indicating whether preemption has occurred in each of a plurality of groups included in the sub-reference DL resource. In this case, the first sub-reference DL resource is a set of OFDM symbols located in the n-2th slot of the reference DL resource. Also, the second sub-reference DL resource is a set of OFDM symbols located in the n-1th slot of the reference DL resource. 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-2th slot has been 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 6th OFDM symbol to the 10th OFDM symbol of the n-2th slot is 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 of the n-1th slot is punctured by preemption. Also, if the preemption indicator indicates the second sub-reference DL resource, the second bit of the bitmap of the two bits of the preemption indicator indicates whether the second OFDM symbol of the n-1th slot is punctured by preemption.

[0190] In the embodiment of Figure 28, the terminal receives the first and second bits as a preemption indicator from the resource scheduled from the base station and determines whether preemption has occurred for each of a plurality of groups including the sub-reference DL resource indicated by the base station. In this case, the terminal performs decoding for the scheduled resource according to the determination of whether transmission from the base station to the terminal has occurred.

[0191] FIG. 29 is a diagram illustrating OFDM symbols in which a bitmap of a preemption indicator indicates whether preemption is possible according to still another embodiment of the present invention. The base station signals, using RRC configuration, to the terminal how many OFDM symbols out of the group indicated via the preemption indicator are to be grouped into one group. Specifically, the base station signals to the terminal the time-domain OFDM symbol granularity using RRC configuration. The terminal determines, using RRC configuration, how many OFDM symbols the preemption indicator groups into one group. Also, 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 groups 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 sequentially indicates S OFDM symbols. 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 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 i = ceil(S / C), the terminal determines that the i-th bit of the preemption indicator indicates whether 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. Also, 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 in the n-2th slot and the first OFDM symbol to the second OFDM symbol in the n-1th slot correspond to the reference DL resource. In this case, 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 in the n-2th slot is punctured by preemption. 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 in the n-2th slot is punctured by preemption. Also, the third bit of the bitmap indicates whether at least one of the OFDM symbols from the 7th OFDM symbol to the 9th OFDM symbol in the n-2th slot is punctured by preemption, and the fourth bit of the bitmap indicates whether at least one of the OFDM symbols from the 10th OFDM symbol in the n-2th slot and the 1st OFDM symbol and the 2nd OFDM symbol in the n-1th slot is punctured by preemption.

[0193] In the above-described embodiments, each group is limited to including only consecutive OFDM symbols. At this time, based on the premise that each group includes only consecutive OFDM symbols, the terminal determines the OFDM symbol groups indicated by each bit of the bitmap of the preemption indicator. For example, it may be assumed that the reference DL resource includes S OFDM symbols, and among the S OFDM symbols, S1 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 in 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 the second case (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 first OFDM symbol to the third OFDM symbol in the n-2th slot has been punctured by preemption. 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 in the n-2th slot has been punctured by preemption. 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 in the n-2th slot has been punctured by preemption. Also, the fourth bit of the bitmap indicates whether the 10th OFDM symbol of the n-2th slot is punctured by preemption. Also, the fifth bit of the bitmap indicates whether at least one of the first and second OFDM symbols of the n-1th slot is punctured by preemption. In this second case (case #2), a preemption indicator is transmitted for resources that may be preempted. Thus, in this second case (case #2), the base station prevents a decrease in data transmission rate that occurs when the terminal decodes and combines resources that may not be unnecessarily preempted under the assumption that no transmission occurs from the base station. Also, when transmissions for TBs occur simultaneously in different slots, it is unlikely that non-sequential preemption occurs in different slots. Therefore, in this embodiment, the base station can more accurately indicate resources that may be preempted to the terminal.

[0195] In the same OFDM symbol configuration, the terminal determines the OFDM symbol group indicated by each bit of the bitmap of the preemption indicator according to the following embodiment: S1 OFDM symbols are divided into N1=ceil(S1 / C) groups. Among the ceil(S1 / C) groups, the first mod(S1, N1) groups each include C OFDM symbols, and the remaining N1-mod(S1, N1) groups each include C-1 OFDM symbols. Also, S2 OFDM symbols are divided into N2=ceil(S2 / C) groups. Among the ceil(S2 / C) groups, the first mod(S2, N2) groups each include C OFDM symbols, and the remaining N2-mod(S2, N2) groups each include C-1 OFDM symbols.

[0196] In the third case (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 first OFDM symbol to the third OFDM symbol of the n-2th slot is punctured by preemption. 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-2th slot is punctured by preemption. The third bit of the bitmap indicates whether at least one of the OFDM symbols from the seventh OFDM symbol to the eighth OFDM symbol of the n-2th slot is punctured by preemption. Also, the fourth bit of the bitmap indicates whether at least one of the 9th and 10th OFDM symbols of the n-2th slot is punctured by preemption. Also, the fifth bit of the bitmap indicates whether at least one of the 1st and 2nd OFDM symbols of the n-1th slot is punctured by preemption. In this third case (case #3), a preemption indicator is transmitted to indicate resources that may be preempted. Thus, the base station prevents a decrease in data transmission rate that occurs when the terminal decodes and combines resources that may not be preempted under the assumption that no transmission occurs from the base station. Also, when transmissions for TBs occur simultaneously in different slots, it is unlikely that non-sequential preemption occurs in different slots. Thus, the base station can more accurately indicate resources that may be preempted to the terminal.In this embodiment, the base station further divides resources in which preemption may occur even in the same slot as evenly as possible in units of OFDM symbols, i.e., the difference in the length of OFDM symbols in each group is allowed to be at least 1. Thus, the base station can maximally prevent a decrease in data transmission rate even when the smallest number of preemptions occur in units of OFDM symbols.

[0197] In the embodiment of Figure 29, the terminal additionally receives a preemption indicator from the scheduled resource from the base station and determines whether preemption has occurred for each of a plurality of groups including the sub-reference DL resource indicated by the base station. The terminal performs decoding for the scheduled resource in response to the determination of 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. In particular, 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 a part of a redundant value to the payload of the preemption indicator, and adjusts the size of the payload of the preemption indicator and the size of the payload indicated by the RRC signal. The redundant value is 0. In another specific embodiment, the redundant value is 1.

[0199] The reference DL resource is partitioned into multiple groups not only in the time domain but also in the frequency domain. A related embodiment will now be described. If the reference DL resource includes S OFDM symbols and 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. Thus, 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 the reference DL resource to which each of the NxF bits corresponds. In a specific embodiment, N=14 and F=1. Alternatively, N=7 and F=2 may be used. The base station sets the values ​​of N and F using an RRC signal. The terminal acquires the values ​​of N and F based on the RRC signal.

[0200] If N=14 and F=1, the terminal divides B PRBs into one group. If N=7 and F=2, the terminal divides ceil(B / 2) PRBs out of 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) PRBs out of 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 pre - emption indicator indicates whether pre - emption has occurred in each group. At this time, the base station pads the remaining (N - S)×F bits of the pre - emption indicator with unnecessary values to make the size of the pre - emption 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] Divide the S OFDM symbols 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 non-consecutive OFDM symbols in the time domain, the S OFDM symbols are partitioned into N groups according to the following embodiment. The S OFDM symbols are partitioned into M groups including consecutive OFDM symbols in the time domain. Let the number of OFDM symbols included in each group be S1, S2, ..., S M The M groups are further divided into a number of subgroups. The number of subgroups contained in each of the M groups is N1, N2, ..., N M In this case, N1+N2+…+N M Satisfy N.

[0204] The i-th group is N i The OFDM symbols contained in the i-th group are C i =floor(S i / N i ) OFDM symbols i It is divided into subgroups. i If we index the OFDM symbols in time order starting from 1, then N i The subgroups are denoted as follows: The first group is {1, 2, …, C i}, the second group is {C i +1, C i +2, …, 2*C i}, N i - The first group is {(N-2)*C i +1, (N i -2)*C i +2, …, (N i -1)*C i}, N i The th group is {(N i -1)*C i , (N i -1)*C i +1, ..., S}. In this case, N i Group C i It contains more than one OFDM symbol.

[0205] In this case, N in the i-th group iThe number of OFDM symbols included in each of the subgroups is determined as in the following embodiment. In particular, the difference between the number of OFDM symbols included in each of the subgroups included in the i-th group is at most one. i If we index the OFDM symbols in time order starting from 1, then N i The subgroups are divided as follows: i The first mod(S i , N i ) groups are ceil(S i / N i ) OFDM symbols, and the remaining N i -mod(S i , N i ) groups are floor(S i / N i ) OFDM symbols.

[0206] If the OFDM symbol corresponding to the reference DL resource is included in two or more slots, the OFDM symbol corresponding to the reference DL resource is classified into N groups according to the following embodiment. 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 The M groups are further divided into a number of subgroups. The number of subgroups contained in each of the M groups is N1, N2, ..., N M In this case, N1+N2+…+N M Satisfy N.

[0207] The i-th group is N i The OFDM symbols contained in the i-th group are C i =floor(S i / N i ) OFDM symbols i It is divided into subgroups. i If we index the OFDM symbols in time order starting from 1, then N iThe subgroups are denoted as follows: The first group is {1, 2, …, C i}, the second group is {C i +1, C i +2, …, 2*C i}, N i - The first group is {(N-2)*C i +1, (N i -2)*C i +2, …, (N i -1)*C i}, N i The th group is {(N i -1)*C i , (N i -1)*C i +1, ..., S}. In this case, N i Group C i It contains more than one OFDM symbol.

[0208] In this case, N in the i-th group i The number of OFDM symbols included in each of the subgroups is determined as in the following embodiment. In particular, the difference between the number of OFDM symbols included in each of the subgroups included in the i-th group is at most one. i If we index the OFDM symbols in time order starting from 1, then N i The subgroups are divided as follows: i The first mod(S i , N i ) groups are ceil(S i / N i ) OFDM symbols, and the remaining N i -mod(S i , N i ) groups are 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 resource include discontinuous OFDM symbols in the time domain, the OFDM symbols corresponding to the reference DL resource are classified into N groups according to the following embodiment. 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 The M groups are further divided into a number of subgroups. The number of subgroups contained in each of the M groups is N1, N2, ..., N M In this case, N1+N2+…+N M Satisfy N.

[0210] The i-th group is N i The OFDM symbols contained in the i-th group are C i =floor(S i / N i ) OFDM symbols i It is divided into subgroups. i If we index the OFDM symbols in time order starting from 1, then N i The subgroups are denoted as follows: The first group is {1, 2, …, C i}, the second group is {C i +1, C i +2, …, …, 2*C i}, N i - The first group is {(N-2)*C i +1, (N i -2)*C i +2, …, (N i -1)*C i}, N i The th group is {(N i -1)*C i , (N i -1)*C i +1, ..., S}. In this case, N i Group C i It contains more than one OFDM symbol.

[0211] In this case, N in the i-th group i The number of OFDM symbols included in each of the subgroups is determined as in the following embodiment. In particular, the difference between the number of OFDM symbols included in each of the subgroups included in the i-th group is at most one. i If we index the OFDM symbols in time order starting from 1, then N i The subgroups are divided as follows: i The first mod(S i , N i ) groups are ceil(S i / N i ) OFDM symbols, and the remaining N i -mod(S i , N i ) groups are 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. More 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. More specifically, the numbers of subgroups included in each of the M groups, N1, N2, ..., N M is then determined by the formula: N1 = round(NM) * S1 / S) + 1, N2 = round(NM) * S2 / S) + 1, …, N M-1 =round(NM)*S M-1 / S)+1, N M =N-(N1+N2+…+N M-1 ) In the above formula, the rounding operation round(x) may be replaced with floor(x+0.5) indicating a descending operation or ceil(x-0.5) indicating an ascending operation. In another embodiment, the number of subgroups included in each of the M groups is N1, N2, ..., N M is then determined by the formula: 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 formula, the rounding operation round(x) may be replaced with floor(x+0.5) indicating a descending operation or ceil(x-0.5) indicating an ascending operation.

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

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

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

[0216]

number

[0217] In the above formula, ceil(x) denotes the ascending operation.

[0218] In another embodiment, if the number of OFDM symbols included in the subgroups included in each of the M groups is limited to a number smaller than C, the number of subgroups N1, N2, ..., N 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 , In this case, C

[0219]

number

[0220] In the above formula, ceil(x) indicates an ascending operation. Also, in the above formula, a i The value of is determined by the following formula:

[0221]

number

[0222] The indexing of the M groups is set to satisfy the following equation: S1 ≥ S2 ≥ … ≥ S M

[0223] In this case, if the groups include the same number of OFDM symbols, 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 limited to a number smaller than C, and the number of OFDM symbols included in the subgroups of a group that includes more OFDM symbols is made lower. In another specific embodiment, the indexing of the M groups is set to satisfy the following formula: S1 / ceil(S1 / C)≧S2 / ceil(S2 / C)≧…≧S M =ceil(S M / C) In this case, if the groups include the same number of OFDM symbols, 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 limited to a number smaller than C, and the number of OFDM symbols included in the subgroups of a group that includes more OFDM symbols is made lower.

[0224] In another specific embodiment, the indexing of the M groups is set to satisfy the following formula: ceil(S1 / C)≦ceil(S2 / C)≦…≦ceil(S M / C) In this case, if the groups include the same number of OFDM symbols, 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 limited to a number smaller than C, and the number of OFDM symbols included in the subgroups of a group that includes more OFDM symbols is made lower.

[0225] In another specific embodiment, the indexing of the M groups is set to satisfy the following formula: ceil(S1 / C)≧ceil(S2 / C)≧…≧ceil(S M / C) In this case, if the groups include the same number of OFDM symbols, 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 limited to a number smaller than C, and the number of OFDM symbols included in the subgroups of a group that includes more OFDM symbols is made lower. In the above formula, the rounding operation round(x) may be replaced with floor(x+0.5) indicating a descending operation or ceil(x-0.5) indicating an ascending operation.

[0226] As described above, the reference DL resource indicated by the preemption indicator includes all PRBs of the BWP. The preemption indicator divides the reference DL resource into 14 parts and indicates whether preemption has occurred in the 14 parts using a bitmap having 14 bits. 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 the UE to monitor the preemption indicator is one of 1 slot, 2 slots, and 4 slots.

[0227] If the terminal is configured to perform Carrier Aggregation (CA) to aggregate multiple component carriers (cells), the terminal monitors a preemption indicator indicating preemption information of one carrier to another carrier. In this case, the preemption indicator is called a cross-carrier DL preemption indicator. The transmission period of the preemption indicator will be described in detail with reference to FIG. 30.

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

[0229] The embodiments of Figures 30(a) and 30(b) relate to a case where a terminal is configured to monitor a preemption indicator in a cell with a subcarrier spacing of 60 KHz, and the preemption indicator is configured to indicate information about preemption occurring in a cell with a subcarrier spacing of 15 KHz. In a cell with a subcarrier spacing of 60 KHz, the OFDM symbols corresponding to the reference DL resource are three or four OFDM symbols depending on the relationship between the OFDM symbol position of the CORESET for monitoring the preemption indicator and the OFDM symbol position of the cell with a subcarrier spacing of 15 KHz. In particular, 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 the cell with a subcarrier spacing of 15 KHz, the OFDM symbols corresponding to the reference DL resource are four OFDM symbols. Also, if the symbol position of CORESET for monitoring the preemption indicator in a cell with a subcarrier spacing of 60KHz starts from the third or fourth OFDM symbol position of a cell with a subcarrier spacing of 15KHz, the OFDM symbols corresponding to the reference DL resource are three OFDM symbols. Thus, in a cell with a subcarrier spacing of 60KHz, the number of OFDM symbols corresponding to the reference DL resource may vary depending on the relationship between the OFDM symbol position of CORESET for monitoring the preemption indicator and the OFDM symbol position of the cell with a subcarrier spacing of 15KHz. Also, the number of OFDM symbols during the monitoring period of the preemption indicator is N_symb*T_INT*2 (μ-μ_INT)In this case, N_symb is the number of OFDM symbols that the slot contains. If a normal cyclic prefix (CP) is used, N_symb is 14. If an extended CP is used, N_symb is 12. Also, T_INT is the monitoring period of the preemption indicator. T_INT can be one of 1, 2, and 4. μ_INT is the subcarrier interval of the carrier that transmits the DL preemption indicator, which is 15*2 μ_INT μ is a value that satisfies that the subcarrier spacing of the carrier that the preemption indicator indicates information about preemption is 15*2 μ This value satisfies the requirement of KHz.

[0230] The base station signals a preemption indicator in an integer number of slot periods. The terminal monitors the preemption indicator in an integer number of slot periods. The base station monitors the preemption indicator in an integer number of slot periods. (μ-μ_INT) The terminal sets the values ​​of T_INT and μ_INT such that T_INT*2 is a natural number, and signals the corresponding values ​​to the terminal. (μ-μ_INT) The terminal expects the values ​​of T_INT, μ, and μ_INT such that T_INT*2 (μ-μ_INT) It is not expected that the value of T_INT, the value of μ, and the value of μ_INT will be a fraction. (μ-μ_INT) If the value of T_INT is a fraction, the terminal shall ignore the value of T_INT. Alternatively, the terminal shall (μ-μ_INT) If the terminal receives the T_INT value, μ value, and μ_INT value that make the value of T_INT*2 a decimal point, the terminal determines that the corresponding setting from the base station is an error case. In this case, the terminal does not need to perform any operation. Alternatively, the terminal may determine that the T_INT value, μ value, and μ_INT value are a decimal point. (μ-μ_INT)If the terminal receives values ​​of T_INT, μ, and μ_INT such that the value of T_INT*2 is a decimal, the terminal does not need to monitor to receive a preemption indicator from the base station. In particular, 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 does not expect T_INT*2 (μ-μ_INT) The values ​​of T_INT, μ, and μ_INT are set so that is a natural number.

[0231] Also, the terminal is N_symb*T_INT*2 (μ-μ_INT) The terminal expects the values ​​of T_INT, μ, and μ_INT such that N_symb*T_INT*2 is a natural number. (μ-μ_INT) It is not expected that the values ​​of T_INT, μ, and μ_INT will be fractional. (μ-μ_INT) If the value of T_INT is a fraction, the terminal shall ignore the value of T_INT. Alternatively, the terminal shall (μ-μ_INT) If the terminal receives a T_INT value, a μ value, and a μ_INT value that make the value of T_INT*2 a decimal point, the terminal determines that the corresponding setting is an error case. In this case, the terminal does not need to take any action. Alternatively, the terminal (μ-μ_INT) If the terminal receives values ​​of T_INT, μ, and μ_INT such that the value of N_symb is a decimal, the terminal does not need to monitor to receive a 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 does not expect N_symb*T_INT*2 (μ-μ_INT) The values ​​of T_INT, μ, and μ_INT are set so that is a natural number.

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

[0233] In Fig. 30, an example in which the terminal is configured to perform CA has been described, but the embodiment described through Fig. 30 is also applied to the case in which the terminal operates in one cell (or carrier). In particular, if multiple BWPs configured with different subcarrier settings are used in the terminal and the terminal is configured to monitor a preemption indicator in one BWP from another BWP, the above-mentioned embodiment is applied. 31 and 32 are diagrams illustrating an operation method of a base station and a terminal according to an embodiment of the present invention.

[0234] The base station generates a preemption indicator indicating preempted (or punctured) resources (S3101). The base station transmits the preemption indicator to the terminal based on a pre-specified period (S3103). More specifically, the base station transmits the preemption indicator at a time point corresponding to the pre-specified period. In this case, the base station signals the pre-specified period to the terminal.

[0235] The preemption indicator indicates information on the remaining OFDM symbols excluding some symbols among the OFDM symbols included in the slot indicated by the preemption indicator. In particular, the reference resource indicated by the preemption indicator does not include the OFDM symbol set as the UL symbol. In this case, the UL symbol is set to the RRC signal. In particular, the RRC signal is a cell-specific RRC signal. Also, the preemption indicator indicates only information on resources corresponding to DL symbols or flexible symbols that can become DL symbols. The reference resource indicated by the preemption indicator is determined according to the embodiments described with reference to FIG. 21 to FIG. 26.

[0236] Also, the preemption indicator divides the 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 to be punctured for each of the plurality of groups. In this case, the number of the plurality of groups is preset. In particular, the number of the plurality of groups is the number of bits of the bitmap included in the preemption indicator. In another specific embodiment, the number of the plurality of groups is determined according to the granularity of the OFDM symbols set by the base station.

[0237] If the number of groups is N and the number of OFDM symbols indicated by the preemption indicator is S, the base station groups the first mod(S,N) groups among the N groups to include ceil(S / N) OFDM symbols, and groups the remaining N-mod(S,N) groups to include floor(S / N) OFDM symbols. In this case, mod(a,b) is a-floor(a / b)*b, floor(x) is the largest integer number equal to or smaller than x, and ceil(x) is the smallest integer number equal to or larger than x. In a specific embodiment, the base station groups the groups indicated by the preemption indicator according to the embodiment described with reference to FIG. 27 to FIG. 29.

[0238] The terminal monitors the preemption indicator in units of an integer number of slots. Therefore, the base station transmits a preemption indicator so that the terminal monitors the preemption indicator in units of an integer number of slots. In particular, the number of OFDM symbols in a predetermined period is set to N_symb*T_INT*2 (μ-μ_INT) In this case, 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 the period when the subcarrier interval of the carrier that transmits the preemption indicator is 15*2 μ_INT In addition, μ is a value that satisfies that the subcarrier interval of the carrier in which the preemption indicator indicates information about preemption is 15*2 μ This value satisfies that the base station is N_symb*T_INT*2 (μ-μ_INT) The base station sets the values ​​of T_INT, μ, and μ_INT so that μ 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 in FIG.

[0239] Also, 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.

[0240] The terminal periodically monitors a preemption indicator indicating a preempted (or punctured) resource (S3201). If the terminal receives the preemption indicator, the terminal determines a preempted resource among resources scheduled to the terminal based on the preemption indicator (S3203). In particular, the terminal assumes that no transmission is being performed from a resource indicated by the preemption indicator among resources scheduled to the terminal. In addition, the terminal determines a resource in which preemption has occurred from the base station to the terminal according to the value of the preemption indicator by receiving the preemption indicator. Thus, the terminal determines whether transmission from the base station has occurred in a resource indicated by preemption among scheduled resources. In particular, the terminal determines that transmission from the base station to the terminal has occurred in one or more OFDM symbols corresponding to each bit based on the value of the bit included in the preemption indicator. For example, if the value of any one of the bits included in the preemption indicator is a first value, the terminal determines that transmission from the base station to the terminal has occurred in one or more OFDM symbols corresponding to the corresponding bit. Also, if the value of any one of the bits included in the preemption indicator is a second value, the terminal determines that transmission from the base station to the terminal has occurred in one or more OFDM symbols corresponding to the corresponding bit. The terminal decodes data received from the base station based on the resource from which the transmission from the base station to the terminal has occurred. In this case, the data includes at least one of a data channel and a control channel. The preemption indicator indicates information on the remaining OFDM symbols excluding some symbols among the OFDM symbols included in the slot indicated by the preemption indicator. Thus, the terminal determines that the information on the remaining OFDM symbols excluding some symbols among the OFDM symbols included in the slot indicated by the preemption indicator is indicated. In more detail, the terminal determines the resource 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 resource indicated by the preemption indicator does not include the OFDM symbol set as the UL symbol. In this case, the UL symbol is set by the RRC signal. In particular, the RRC signal is a cell-specific RRC signal. Also, the terminal determines that the preemption indicator indicates only information on the resource corresponding to the DL symbol or the flexible symbol that can become the DL symbol. In another specific embodiment, the terminal determines the resource indicated by the preemption indicator based on information on the OFDM symbol indicated through the preemption indicator. In this case, the terminal obtains information on the OFDM symbol indicated by the preemption indicator from the RRC signal. In a specific embodiment, the terminal determines the resource indicated by the preemption indicator according to the embodiment described with reference to FIG. 21 to FIG. 26.

[0241] Also, the preemption indicator divides the multiple OFDM symbols indicated by the preemption indicator into multiple groups, and indicates whether at least one of the multiple groups includes one or more OFDM symbols to be punctured or preempted for each group. In this case, the terminal determines whether or not transmission from the base station to the terminal occurs from all of the one or more OFDM symbols included in the group corresponding to any one bit. In particular, if the value of any one bit is a first value, the terminal determines that transmission from the base station to the terminal occurs from all of the one or more OFDM symbols included in the group corresponding to the corresponding bit. Also, if the value of any one bit is a second value, the terminal determines that transmission does not occur from all of the one or more OFDM symbols included in the group corresponding to the corresponding bit. Also, the number of the multiple groups is specified in advance. In particular, the number of the multiple groups is the number of bits of a bitmap included in the preemption indicator. In another specific embodiment, the number of the multiple groups is determined according to the granularity of the OFDM symbols set by the base station.

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

[0243] The terminal monitors the preemption indicator in units of an integer number of slots. In detail, the number of OFDM symbols in a pre-specified period is set to N_symb*T_INT*2 (μ-μ_INT) In this case, 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 the period when the subcarrier interval of the carrier that transmits the preemption indicator is 15*2 μ_INT In addition, μ is a value that satisfies that the subcarrier interval of the carrier in which the preemption indicator indicates information about preemption is 15*2 μ This is a value that satisfies the requirement of N_symb*T_INT*2 KHz. (μ-μ_INT) The terminal expects values ​​of T_INT, μ, and μ_INT such that N_symb*T_INT*2 is a natural number. (μ-μ_INT) The terminal may ignore values ​​of T_INT, μ, and μ_INT that cause T_INT*2 (μ-μ_INT) If the terminal receives a T_INT value, a μ value, and a μ_INT value that make the value of T_INT*2 a decimal point, the terminal determines that the corresponding setting is an error case. In this case, the terminal does not need to take any action. Alternatively, the terminal(μ-μ_INT) If the terminal receives values ​​of T_INT, μ, and μ_INT such that the value of μ_INT is a decimal, the terminal does not need to monitor to receive a preemption indicator from the base station. In a specific embodiment, the terminal expects values ​​of T_INT, μ, and μ_INT according to the embodiment described in FIG.

[0244] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and are not limiting. For example, each component described as a single form may be implemented in a distributed form, and each component described as a distributed form may be implemented in a combined form.

[0245] The scope of the present invention is indicated by the claims set forth below rather than by the above detailed description, and all modifications and variations derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0246] 100 devices 110 Processor 120 Communications Department 121 Cellular communication interface card 122 Cellular communication interface card 123 Wireless LAN Interface Card 130 Memory 140 User Interface Section 150 display units 200 base stations 210 Processor 220 Communication Module 221 Cellular communication interface card 222 Cellular communication interface card 223 Wireless LAN Interface Card 230 Memory

Claims

1. 1. A base station configured to operate in a wireless communication system, the base station comprising: A communication module; a processor configured to control the communication module; The processor, A preemption indicator is generated to indicate a preempted resource within a pre-specified period, the pre-specified period including a first plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols including one or more uplink (UL) symbols and one or more downlink (DL) symbols, or one or more flexible symbols not configured as a UL symbol or a DL symbol, and a cell-specific radio resource control (RRC) is generated to indicate a preemption indicator. A flexible symbol configured by a cell-specific (UE-specific) RRC signal is further configured as an UL symbol by a UE-specific RRC signal, and the one or more UL symbols include an UL symbol configured by the cell-specific RRC signal and the UL symbol configured by the UE-specific RRC signal; transmitting a group common physical downlink control channel (PDCCH) including the preemption indicator to a terminal of the wireless communication system based on a predetermined period; The preemption indicator indicates the preempted resource among a second plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols that are OFDM symbols included in the first plurality of OFDM symbols other than the UL symbol set by the cell-specific RRC signal, and the second plurality of OFDM symbols includes the UL symbol set by the terminal-specific RRC signal. Base station.

2. the second plurality of OFDM symbols are divided into a plurality of groups, and the preemption indicator includes a bitmap, each bit in the bitmap corresponding to each of the plurality of groups, and indicating whether at least one OFDM symbol in the group corresponding to each bit is preempted; The number of the plurality of groups is specified in advance, The number of the groups is N, the second plurality of OFDM symbols is S in number; the processor is configured to group a first mod(S,N) number of groups of the N groups such that each of the first mod(S,N) groups contains ceil(S / N) OFDM symbols and each of the remaining N-mod(S,N) groups contains floor(S / N) OFDM symbols; The mod(x, y) represents x-floor(x / y)*y, where floor(x) represents the largest integer less than or equal to x; The ceil(x) represents the smallest integer greater than or equal to x; The base station according to claim 1 .

3. The number of the first plurality of OFDM symbols is N_symb*T_INT*2 (μ－μ＿ＩＮＴ) and N_symb represents the number of OFDM symbols contained in a slot, T_INT represents a monitoring period of the preemption indicator, μ_INT is a subcarrier interval of the carrier on which the preemption indicator is transmitted, which is 15*2 μ＿ＩＮＴ KHz, μ is the subcarrier spacing of the carrier corresponding to the preemption indicator, which is 15*2 μ KHz, The processor calculates N_symb*T_INT*2 (μ－μ＿ＩＮＴ) is configured to set the values ​​of T_INT, μ, and μ_INT so that The base station according to claim 1 .

4. The processor is configured to transmit a control channel including the preemption indicator in a control resource set (CORESET) corresponding to a bandwidth part (BWP) in which a data channel is scheduled; The preemption indicator indicates the total bandwidth of the BWP used by the terminal, The BWP is narrower than or equal to the bandwidth set in the terminal, and is a frequency band in which the terminal transmits and receives signals. The base station according to claim 1 .

5. 1. A terminal configured to operate in a wireless communication system, comprising: A communication module; a processor configured to control the communication module; The processor, The group common physical downlink control channel (PDCCH) including a preemption indicator indicating a preempted resource within a pre-specified period is periodically monitored, and the pre-specified period includes a first plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols including one or more uplink (UL) symbols and one or more downlink (DL) symbols, or one or more flexible symbols that are not set as a UL symbol or a DL symbol, and a cell-specific radio resource control (RRC) is periodically monitored. A flexible symbol configured by a cell-specific (UE-specific) RRC signal is further configured as an UL symbol by a UE-specific RRC signal, and the one or more UL symbols include an UL symbol configured by the cell-specific RRC signal and the UL symbol configured by the UE-specific RRC signal; When receiving the preemption indicator, determining a second plurality of OFDM symbols in which the preemption indicator indicates the preempted resources, the second plurality of OFDM symbols being OFDM symbols included in the first plurality of OFDM symbols other than the UL symbol configured by the cell-specific RRC signal, the second plurality of OFDM symbols including the UL symbol configured by the terminal-specific RRC signal; determining, when receiving the preemption indicator, a resource corresponding to the second plurality of OFDM symbols based on the preemption indicator, on which a transmission from a base station to the terminal occurs; Decoding data received from the base station based on the determined resources. Terminal.

6. the second plurality of OFDM symbols are divided into a plurality of groups, and the preemption indicator includes a bitmap, each bit in the bitmap corresponding to each of the plurality of groups, and indicating whether at least one OFDM symbol in the group corresponding to each bit is preempted; The number of the plurality of groups is specified in advance, The number of the groups is N, the second plurality of OFDM symbols is S in number; Each of the mod(S,N) groups contains ceil(S / N) OFDM symbols, and each of the N-mod(S,N) groups contains floor(S / N) OFDM symbols; The mod(x, y) represents x-floor(x / y)*y, where floor(x) represents the largest integer less than or equal to x; The ceil(x) represents the smallest integer greater than or equal to x; The terminal according to claim 5.

7. The number of the first plurality of OFDM symbols is N_symb*T_INT*2 (μ－μ＿ＩＮＴ) and N_symb represents the number of OFDM symbols contained in a slot, T_INT represents a monitoring period of the preemption indicator, μ_INT is a subcarrier interval of the carrier on which the preemption indicator is transmitted, which is 15*2 μ＿ＩＮＴ KHz, μ is the subcarrier spacing of the carrier corresponding to the preemption indicator, which is 15*2 μ KHz, The value of T_INT, the value of μ, and the value of μ_INT are N_symb*T_INT*2 (μ－μ＿ＩＮＴ) is set to be a natural number, The terminal according to claim 5.

8. The preemption indicator indicates the entire bandwidth of a Bandwidth part (BWP) used by the terminal, The BWP is narrower than or equal to the bandwidth set in the terminal, and is a frequency band in which the terminal transmits and receives signals. The terminal according to claim 5.

9. A method for operating a terminal in a wireless communication system, comprising: a processor of the terminal periodically monitoring a group common physical downlink control channel (PDCCH) including a preemption indicator indicating a preempted resource within a prespecified period, the prespecified period including one or more uplink (UL) symbols and a first plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols including one or more downlink (DL) symbols for downlink transmission, or one or more flexible symbols not set as a UL symbol or a DL symbol, and a cell-specific radio resource control (RRC) a flexible symbol configured by a cell-specific (UE-specific) RRC signal is further configured as an UL symbol by a UE-specific RRC signal, the one or more UL symbols including an UL symbol configured by the cell-specific RRC signal and the UL symbol configured by the UE-specific RRC signal; When receiving the preemption indicator, the processor of the terminal determines a second plurality of OFDM symbols for which the preemption indicator indicates the preempted resources, the second plurality of OFDM symbols being OFDM symbols included in the first plurality of OFDM symbols other than the UL symbol configured by the cell-specific RRC signal, the second plurality of OFDM symbols including the UL symbol configured by the terminal-specific RRC signal; determining, upon receiving the preemption indicator, resources corresponding to the second plurality of OFDM symbols on which transmission from a base station to the terminal will occur based on the preemption indicator; and decoding, by the processor of the terminal, data received from the base station based on the determined resources. How it works.

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