Method and apparatus for channel access in a wireless communication system

Abstract

A method for a terminal in an unlicensed frequency band to perform a channel access process, comprising: receiving information about the type of the channel access process in the unlicensed frequency band from a base station; when the channel access process is a frame-based channel access process, receiving frame-based channel access process configuration information from the base station, the frame-based channel access process configuration information including at least one of fixed frame period (FFP) information, channel occupancy time (COT) information in the FFP, or fixed frame start time slot offset information; based on the received frame-based channel access process configuration information, determining whether the base station is occupying the channel; and when it is determined that the base station is occupying the channel, sending a signal to the base station and receiving a signal from the base station.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving data in a wireless communication system, and more particularly, to a channel access method and apparatus in a wireless communication system. Background Art

[0002] In order to meet the growing demand for wireless data services after the commercialization of the fourth generation (4G) communication system, a lot of efforts have been made to develop pre-fifth generation (5G) communication systems or 5G communication systems. This is one reason why "5G communication system" or "pre-5G communication system" is called "super 4G network communication system" or "post-long term evolution (LTE) system". The 5G communication system defined in 3GPP is called the New Radio (NR) system. In order to achieve high data rates, 5G communication systems are being developed to be implemented in ultra-high frequency bands (millimeter waves (mmWave)), such as 60GHz bands. In order to reduce the path loss of radio waves in such ultra-high frequency bands and increase the transmission distance of radio waves in 5G communication systems, various technologies have been discussed and applied to NR systems, such as: beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming and massive antennas. In addition, in order to improve the system network for 5G communication system, various technologies have been developed, such as evolved small cell, advanced small cell, cloud radio access network (Cloud-RAN), ultra-dense network, device-to-device communication (D2D), wireless backhaul, mobile network, cooperative communication, coordinated multi-point (CoMP), and interference cancellation. In addition, for 5G communication system, other technologies have been developed, such as hybrid frequency shift keying (FSK) and orthogonal amplitude modulation (QAM) (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access schemes.

[0003] The Internet has evolved from a human-based connection network (where humans create and consume information) to the Internet of Things (IoT), where distributed configurations such as objects exchange information with each other to process information. Internet of Everything (IoE) technology is emerging, in which technologies related to IoT are combined with technologies for processing big data, such as through connection with cloud servers. In order to realize the Internet of Things, various technical components are required, such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, security technology, etc. In recent years, the following technologies have been studied, including: sensor networks for connecting objects, machine-to-machine (M2M) communication, machine type communication (MTC), etc. In the IoT environment, smart Internet technology (IT) services can be provided to collect and analyze data obtained from objects connected to each other to create new value in human life. As existing information technology (IT) technologies and various industries merge and combine with each other, IoT can be applied to various fields, such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart appliances, high-quality medical services, etc.

[0004] In this regard, various attempts are being made to apply 5G communication systems to IoT networks. For example, 5G communications such as sensor networks, M2M communications, MTC, etc. are being implemented by using technologies such as beamforming, MIMO, array antennas, etc. The application of the above-mentioned cloud radio access network (RAN) as a big data processing technology may be an example of the fusion of 5G communication technology and IoT technology.

[0005] As described above, due to the development of mobile communication systems, various services can be provided, and thus, a method of efficiently providing such services is required. Summary of the invention

[0006] Technical issues

[0007] A method and apparatus for efficiently providing a service in a wireless communication system are provided.

[0008] Solution

[0009] According to the embodiment, the channel access method of the terminal in the wireless communication system includes: receiving information about the channel access process method in the unlicensed frequency band of the base station from the base station; receiving at least one information of the fixed frame period, offset and channel occupancy time in the fixed frame period from the base station via at least one signaling among the system information block (SIB) signaling and the radio resource control (RRC) signaling; checking the channel access of the base station by searching the physical downlink control channel (PDCCH) according to the PDCCH search period and resources configured within the fixed frame period; and when it is determined that the base station has accessed the unlicensed frequency band, performing signal sending and receiving according to the scheduling.

[0010] Advantageous Effects of the Present Disclosure

[0011] According to the embodiments, services can be effectively provided in a wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 2 is a diagram showing a transmission structure in a time-frequency domain as a radio resource region of a New Radio (NR) system.

[0013] Figure 2 is a diagram of a channel access procedure in an unlicensed band according to an embodiment.

[0014] Figure 3 is a diagram of a channel access procedure in an unlicensed band according to another embodiment.

[0015] Figure 4 is a diagram of a downlink and uplink scheduling method and a resource area in an NR system according to an embodiment.

[0016] Figure 5 is a graph of channel occupancy time according to an embodiment.

[0017] Figure 6 is a graph of remaining channel occupancy time according to an embodiment.

[0018] Figure 7 is a flow chart of the operation of a base station according to an embodiment.

[0019] Figure 8 is a flowchart of the operation of the terminal according to the embodiment.

[0020] Fig. 9 is a block diagram of an internal configuration of a base station according to an embodiment.

[0021] Fig.10 is a block diagram showing an internal configuration of a terminal according to an embodiment. DETAILED DESCRIPTION

[0022] According to an embodiment of the present disclosure, a method for a terminal in an unlicensed frequency band to perform a channel access process includes: receiving information about the type of the channel access process in the unlicensed frequency band from a base station; when the channel access process is a frame-based channel access process, receiving frame-based channel access process configuration information from the base station, the frame-based channel access process configuration information including at least one of fixed frame period (FFP) information, channel occupancy time (COT) information in the FFP, or fixed frame start time slot offset information; determining whether the base station is occupying the channel based on the received frame-based channel access process configuration information; and when it is determined that the base station is occupying the channel, sending a signal to the base station and receiving a signal from the base station.

[0023] Determining whether a base station is occupying a channel may include determining that the base station is occupying the channel when a demodulation reference signal (DMRS), downlink control information (DCI), or DCI including slot format information (SFI) sent via a physical downlink control channel (PDCCH) is received or when a preset signal is received.

[0024] The method may further include: receiving remaining channel occupancy time (RCOT) information from the base station for not sending downlink signals during the COT, wherein, when it is determined that the base station is occupying the channel, sending signals to and receiving signals from the base station may include: based on the RCOT information, sending uplink signals in the absence of scheduling regarding uplink from the base station.

[0025] Information about the type of channel access procedure in an unlicensed band can be received from a base station via at least one of the following: a master information block (MIB) sent via a physical broadcast channel (PBCH), a system information block (SIB) sent to a PDCCH or a physical downlink shared channel (PDSCH), a random access response (RAR) grant information, or a radio signaling control (RRC) signaling.

[0026] The FFP information may be received via at least one of: TDD_UL_DL_Pattern information included in the SIB, TDD_UL_DL_slotConfig information transmitted via RRC signaling, FFP information or reference time information transmitted via the SIB or RRC signaling.

[0027] Determining whether the base station is occupying the channel may include: determining the FFP through a modulo operation between a preset period and the FFP according to the FFP information; or determining the FFP based on the reference time information and the fixed frame start time slot offset information.

[0028] When it is determined that the base station is not occupying the channel, the following may not be performed: performing scheduling, or transmitting and receiving signals to and from the base station.

[0029] According to an embodiment of the present disclosure, a method for a base station in an unlicensed frequency band to perform a channel access process includes: determining the type of the channel access process in the unlicensed frequency band; when it is determined to use a frame-based channel access process, sending information about the type of the channel access process to a terminal; sending frame-based channel access process configuration information to the terminal, the frame-based channel access process configuration information including at least one of fixed frame period (FFP) information, channel occupancy time (COT) information in the FFP, or fixed frame start time slot offset information; performing a frame-based channel access process according to the frame-based channel access process configuration information; and when it is determined according to the frame-based channel access process that a channel of the unlicensed frequency band is in an idle state, sending a signal to the terminal and receiving a signal from the terminal during the COT in the FFP.

[0030] The method may further include transmitting at least one of the following to the terminal: slot format information about slots configuring the COT in the FFP or slot format information about symbols or slots not used during the COT in the FFP.

[0031] The method may further include: when it is determined according to the frame-based channel access procedure that the channel of the unlicensed frequency band is not in an idle state, performing the frame-based channel access procedure again.

[0032] According to an embodiment of the present disclosure, a terminal for performing a channel access process in an unlicensed frequency band includes: a transceiver; at least one memory storing a program and data for performing a channel access process in an unlicensed frequency band; and at least one processor configured to: receive information about the type of channel access process in the unlicensed frequency band from a base station by running the program stored in the memory; when the channel access process is a frame-based channel access process, receive frame-based channel access process configuration information including at least one of fixed frame period (FFP) information, channel occupancy time (COT) information in the FFP, or fixed frame start time slot offset information from the base station; determine whether the base station is occupying the channel based on the received frame-based channel access process configuration information; and when it is determined that the base station is occupying the channel, send a signal to the base station and receive a signal from the base station.

[0033] At least one processor may be further configured to determine that the base station is occupying the channel when a demodulation reference signal (DMRS), downlink control information (DCI), or DCI including time slot format information sent via a physical downlink control channel (PDCCH) is received or a preset signal is received.

[0034] At least one processor may be further configured to: receive remaining channel occupation time (RCOT) information from the base station for not sending downlink signals during the COT; and based on the RCOT information, send uplink signals without scheduling for uplink from the base station.

[0035] Information about the type of channel access procedure in an unlicensed band may be received from a base station via at least one of: a master information block (MIB) sent via a physical broadcast channel (PBCH), a system information block (SIB) sent to a PDCCH or a physical downlink shared channel (PDSCH), random access response (RAR) grant information, or radio resource control (RRC) signaling.

[0036] The FFP information may be received via at least one of: TDD_UL_DL_Pattern information included in the SIB, TDD_UL_DL_slotConfig information transmitted via RRC signaling, FFP information or reference time information transmitted via the SIB or RRC signaling.

[0037] The at least one processor may be further configured to: determine the FFP via a modulo operation between a preset period and the FFP according to the FFP information; or determine the FFP based on the reference time information and the fixed frame start time slot offset information.

[0038] When it is determined that the base station is not occupying the channel, the following may not be performed: performing scheduling, or sending and receiving signals to and from the base station.

[0039] According to an embodiment of the present disclosure, a base station for performing a channel access process in an unlicensed frequency band includes: a transceiver; at least one memory storing a program and data for performing a channel access process in an unlicensed frequency band; and at least one processor configured to run the program stored in the memory to: determine the type of the channel access process in the unlicensed frequency band; when it is determined to use a frame-based channel access process, send information about the type of the channel access process to a terminal; send frame-based channel access process configuration information including at least one of fixed frame period (FFP) information, channel occupancy time (COT) information in the FFP, or fixed frame start time slot offset information to the terminal; perform a frame-based channel access process according to the frame-based channel access process configuration information; and when it is determined that a channel of the unlicensed frequency band is in an idle state according to the frame-based channel access process, send a signal to the terminal and receive a signal from the terminal during the COT in the FFP.

[0040] The at least one processor may be further configured to transmit, to the terminal, at least one of slot format information about slots configuring the COT in the FFP or slot format information about symbols or slots not used during the COT in the FFP.

[0041] The at least one processor may be further configured to, when it is determined according to the frame-based channel access procedure that the channel of the unlicensed band is not in an idle state, perform the frame-based channel access procedure again.

[0042] Mode of the present disclosure

[0043] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. When describing the present disclosure, when it is considered that the relevant well-known functions or configurations may unnecessarily obscure the essence of the present disclosure, their detailed descriptions may be omitted. In addition, the terms used below are defined in consideration of the functions in the present disclosure, and may have different meanings depending on the intentions, habits, etc. of the user or operator. Therefore, the terms should be defined based on the descriptions throughout the specification.

[0044] By referring to the embodiments and drawings described in detail below, it is easier to understand the advantages and features of the present disclosure and the methods for implementing the present disclosure. In this regard, the embodiments of the present disclosure may have different forms and should not be interpreted as being limited to the descriptions set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and the concepts of the present disclosure will be fully conveyed to those of ordinary skill in the art, and the present disclosure will be defined only by the appended claims. Throughout the specification, the same reference numerals represent the same elements.

[0045] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0046] When describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure belongs and are not directly related to the present disclosure will be omitted. By omitting unnecessary descriptions, the gist of the present disclosure can be conveyed more clearly without obscuring the subject matter.

[0047] For the same reason, for the sake of clarity, components may be enlarged, omitted or schematically shown in the drawings. In addition, the size of each component does not fully reflect the actual size. In the accompanying drawings, the same reference numerals represent the same elements.

[0048] By referring to the embodiments and drawings described in detail below, it is possible to more easily understand the advantages and features of the present disclosure and the methods for realizing the present disclosure. In this regard, the embodiments of the present disclosure may have different forms and should not be interpreted as being limited to the descriptions set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and the concepts of the present disclosure will be fully conveyed to those of ordinary skill in the art, and the present disclosure will be defined only by the appended claims. Throughout the specification, the same reference numerals represent the same elements.

[0049] Here, it will be understood that the combination of blocks in the flowchart or process flow diagram can be performed by computer program instructions. Because these computer program instructions can be loaded into a processor of a general-purpose computer, a special-purpose computer, or another programmable data processing device, the instructions executed by the processor of the computer or another programmable data processing device create units for performing the functions described in the flowchart blocks. The computer program instructions can be stored in a computer-usable or computer-readable memory that can direct the computer or another programmable data processing device to implement the functions in a specific manner, and therefore, the instructions stored in the computer-usable or computer-readable memory can also produce a manufacturing item (item) containing the instruction unit, which is used to perform the functions described in the flowchart blocks. The computer program instructions can also be loaded into a computer or another programmable data processing device, and therefore, when a series of operations are performed in the computer or another programmable data processing device, the instructions for operating the computer or another programmable data processing device by generating a computer-executed process can provide operations for performing the functions described in the flowchart blocks.

[0050] In addition, each block can represent a part of a module, segment or code, which includes one or more executable instructions for performing a specified logical function. It should also be noted that in some alternative implementations, the functions mentioned in the frame may not occur in order. For example, the two frames shown continuously can actually be performed substantially simultaneously, or sometimes the frame can be performed in reverse order according to the relatively corresponding function.

[0051] Here, the term "unit" in the embodiment means a software component or hardware component such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and performs a specific function. However, the term "unit" is not limited to software or hardware. The "unit" can be formed in an addressable storage medium, or can be formed to operate one or more processors. Therefore, for example, the term "unit" can refer to a component (such as a software component, an object-oriented software component, a class component, and a task component), and can include a process, a function, an attribute, a process, a subroutine, a program code segment, a driver, a firmware, a microcode, a circuit, data, a database, a data structure, a table, an array, or a variable. The function provided by the component and the "unit" can be associated with a smaller number of components and "units", or can be divided into additional components and "units". In addition, the component and the "unit" can be embodied as one or more central processing units (CPUs) in a reproduction device or a security multimedia card. In addition, in an embodiment, the "unit" can include at least one processor.

[0052] Compared with the existing 4G system, the fifth generation (5G) system takes into account resources related to various services. For example, the most representative services of the 5G system include enhanced mobile broadband (eMBB) service, ultra-reliable and low-latency communication (URLLC) service, massive machine type communication (mMTC) service, and evolved multimedia broadcast / multicast service (eMBMS). However, the present disclosure is not limited to the above examples. In addition, a system providing URLLC services may be referred to as a URLLC system, and a system providing eMBB services may be referred to as an eMBB system. Here, the terms "service" and "system" may be used interchangeably.

[0053] In this way, a variety of services can be provided to users in a communication system, and a method for providing each service in the same section according to characteristics and an apparatus using the method are required to provide the variety of services to users.

[0054] A wireless communication system, such as a Long Term Evolution (LTE) or an Advanced Long Term Evolution (LTE-A) system or a 5G New Radio (NR) system, may be configured such that a terminal receives at least one downlink signal in downlink control information (DCI) (e.g., channel state information reference signal (CSI-RS), physical broadcast channel (PBCH), or physical downlink shared channel (PDSCH)) sent by a base station to the terminal via a physical downlink control channel (PDCCH), the DCI including resource allocation information in which the downlink signal is sent.

[0055] For example, the base station transmits DCI indicating that the terminal is to receive the PDSCH in the subframe n via the PDCCH in the subframe n, and when the terminal receives the DCI, it receives the PDSCH in the subframe n according to the received DCI.

[0056] In addition, the LTE, LTE-A or NR system can be configured so that the terminal sends at least one of the following uplink signals to the base station: uplink control information (e.g., sounding reference signal (SRS), uplink control information (UCI), physical random access channel (PRACH) or physical uplink shared channel (PUSCH)) sent by the base station to the terminal via PDCCH, the DCI including uplink resource allocation information.

[0057] For example, when uplink transmission configuration information (or uplink DCI or uplink grant) is received from the base station via the PDCCH in subframe n, the terminal can perform PUSCH transmission according to a predefined time (e.g., n+4), a time set via a higher-layer signal (e.g., n+k), or an uplink signal transmission time indication information (e.g., n+k) included in the uplink transmission configuration information.

[0058] When a configured downlink transmission is sent from a base station to a terminal via an unlicensed frequency band, or a configured uplink transmission is sent from a terminal to a base station via an unlicensed frequency band, a transmitting device (base station or terminal) may perform a channel access procedure (or listen-before-talk (LBT)) on the unlicensed frequency band configured for signal transmission before or immediately before a configured signal transmission start time point, and when it is determined based on a result of performing the channel access procedure that the unlicensed frequency band is in an idle state, the transmitting device may perform the configured signal transmission by accessing the unlicensed frequency band.

[0059] When it is determined that the unlicensed band is not in an idle state or that the unlicensed band is in an occupied state according to a channel access process performed by a transmitting device, the transmitting device cannot access the unlicensed band and, therefore, may not be able to perform configured signal transmission. In the channel access process in an unlicensed band configured for signal transmission, the transmitting device generally receives a signal in the unlicensed band for a specific time period or a time calculated according to a predefined rule (for example, a time calculated via a random value selected by at least a base station or a terminal), and the idle state of the unlicensed band may be determined by comparing the strength of the received signal with a threshold value predefined or calculated according to a function including at least one of the following variables: a channel bandwidth or a signal bandwidth in which a signal to be transmitted is transmitted, the strength of the transmission power, and the beam width of the transmitted signal.

[0060] For example, when the strength of the signal received by the transmitting device for 25 microseconds (us) is less than a predefined threshold (-72dBm), the transmitting device can determine that the unlicensed band is in an idle state and perform the configured signal transmission. Here, the maximum possible time for signal transmission may be limited according to the following: the maximum channel occupancy time in the unlicensed band defined for each country or region or the type of transmitting device (e.g., base station or terminal, or master or slave). For example, in Japan, after performing a channel access process in an unlicensed band of 5GHz, a base station or terminal can transmit a signal while occupying the channel without having to perform an additional channel access process with a maximum time of 4 milliseconds. When the signal strength received for 25 microseconds is greater than a predefined threshold of -72dBm, the base station determines that the unlicensed band is not in an idle state and does not transmit a signal.

[0061] In the 5G communication system, various technologies will be introduced to provide various services and support high data rates: such as retransmission in units of code block groups, technology for sending uplink signals without uplink scheduling information, etc. Therefore, when 5G communication is to be performed via an unlicensed band, an effective channel access process that considers various variables is required.

[0062] Wireless communication systems have evolved from wireless communication systems that provided voice-centric services in the early stages toward broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards of 3GPP's High Speed ​​Packet Access (HSPA), Long Term Evolution (LTE or Evolved Universal Terrestrial Radio Access (E-UTRA)), Advanced LTE (LTE-A) and LTE-Pro, 3GPP2's High Rate Packet Data (HRPD) and Ultra Mobile Broadband (UMB), IEEE 802.16e, etc. In addition, 5G or NR communication standards are being developed together with 5G wireless communication systems.

[0063] In a 5G wireless communication system, at least one service among eMBB, mMTC and URLLC may be provided to a terminal. The above services may be provided to the same terminal in the same time period. In an embodiment, eMBB may be a service for high-speed transmission of large-capacity data, mMTC may be a service for terminal power minimization and multi-terminal connection, and URLLC may be a service for high reliability and low latency, but is not limited thereto. These three services may be important scenarios in an LTE system or a 5G / NR system after LTE, but the embodiment is not limited thereto.

[0064] In the following, a base station is an entity that allocates resources of a terminal, and may be at least one of an eNode B (eNB), a Node B (NB), a base station (BS), a wireless access unit, a BS controller, and a node on a network. Examples of terminals may include user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, a multimedia system capable of performing a communication function, and the like. In the present disclosure, a downlink (DL) is a wireless transmission path for a signal sent from a base station to a terminal, and an uplink (UL) is a wireless transmission path for a signal sent from a terminal to a base station. In addition, in the following, an embodiment of the present disclosure is described by taking an LTE or LTE-A system as an example, and in order to describe the method and apparatus proposed in the present disclosure, a general term such as a physical channel or a signal in an LTE or LTE-A system may be used. The embodiments of the present disclosure may be applied to other communication systems having a technical background or channel type similar to the mobile communication system described in the present disclosure. For example, a 5G mobile communication technology (5G or NR) developed after LTE-A may be included. In addition, it will be understood by those skilled in the art that the embodiments of the present disclosure may be applied to other communication systems by some modifications without departing from the scope of the present disclosure.

[0065] As a representative example of a broadband wireless communication system, the NR system adopts an orthogonal frequency division multiplexing (OFDM) scheme in DL, and adopts both OFDM and single carrier frequency division multiple access (SC-FDMA) schemes in UL. The multiple access scheme generally allocates and operates time-frequency resources including data or control information to be transmitted for each user to prevent the time-frequency resources from overlapping each other, that is, to establish orthogonality, thereby distinguishing the data or control information of each user.

[0066] The NR system adopts a hybrid automatic repeat request (HARQ) scheme, in which the physical layer resends data when a decoding failure occurs in the initial transmission. In the HARQ scheme, when the receiver cannot accurately decode the data, the receiver sends information indicating the decoding failure (negative acknowledgment (NACK)) to the transmitter so that the transmitter can resend the corresponding data in the physical layer. The receiver combines the data resent by the transmitter with the data that failed to be decoded previously to improve data reception performance. In addition, when the receiver accurately decodes the data, information indicating successful decoding (acknowledgment (ACK)) is sent to the transmitter so that the transmitter can send new data.

[0067] In the present disclosure hereinafter, a channel access process and method in an unlicensed band, and a method and apparatus for sending and receiving signals in an unlicensed band will be described. In detail, the following will be described: in a wireless communication system, specifically, in a system including a node that receives a DL signal in an unlicensed band or a node that is to send a UL signal, a method for performing a frame-based channel access process and a method for sending and receiving signals in an unlicensed band accessed via a frame-based channel access process. The present disclosure proposes the following method: when a node that sends a DL signal in an unlicensed band or a node that is to send a UL performs a frame-based channel access process, the channel occupancy time of the transmitting device and the time slot structure in the channel occupancy time are transmitted via a time slot format indicator, and the UL signal is transmitted by determining the channel occupancy time and the time slot structure by the node that receives the time slot format indicator.

[0068] Figure 1 This is a diagram showing a transmission structure in the time-frequency domain as a radio resource area of ​​the NR system.

[0069] exist Figure 1 In the example, the horizontal axis represents the time domain in the radio resource region, and the vertical axis represents the frequency domain in the radio resource region. In the time domain, the minimum transmission unit may be an OFDM or discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol, and N symb The OFDM symbol 101 or the DFT-s-OFDM symbol may be aggregated to form one time slot 102. According to an embodiment, the OFDM symbol is a symbol for the case of transmitting or receiving a signal by using the OFDM scheme, and the DFT-s-OFDM symbol may include a symbol for the case of transmitting or receiving a signal by using the DFT-s-OFDM or SC-FDMA multiplexing scheme. Hereinafter, for the convenience of description, the present disclosure will be described by indiscriminately referring to the OFDM symbol and the DFT-s-OFDM symbol as an OFDM symbol, and the present disclosure will be described based on DL signal transmission and reception, but the present disclosure is applicable to UL signal transmission and reception.

[0070] When the subcarrier spacing is 15 kHz, one time slot 102 configures one subframe 103, and the lengths of the time slot 102 and the subframe 103 may each be 1 millisecond. According to an embodiment, the number of time slots 102 configuring one subframe 103 and the length of the time slot 102 may vary according to the subcarrier spacing. For example, when the subcarrier spacing is 30 kHz, four time slots 102 may be aggregated to configure one subframe 103. Here, the length of the time slot 102 is 0.5 milliseconds, and the length of the subframe 103 is 1 millisecond. In addition, the radio frame 104 may be a time domain interval configured by 10 subframes 103. The minimum transmission unit in the frequency domain is a subcarrier, and the transmission bandwidth of the entire system is composed of a total of N subframes 103.sc BW 105 subcarriers are configured.

[0071] However, specific values ​​such as the subcarrier spacing, the number of time slots 102 included in the subframe 103, the length of the time slot 102, and the length of the subframe 103 may be variably applied. For example, in the LTE system, the subcarrier spacing is 15 kHz, but two time slots 102 are aggregated to configure one subframe 103, wherein the length of the time slot 102 is 0.5 milliseconds, and the length of the subframe 103 is 1 millisecond.

[0072] In the time-frequency domain, the basic unit of resources is a resource element (RE) 106 and can be indicated as an OFDM symbol index and a subcarrier index. A resource block (RB) 107 or a physical resource block (PRB) is defined as N in the time domain. symb consecutive OFDM symbols 101 and N in the frequency domain SC RB 108. Therefore, one RB 107 in one time slot 102 may include N symb ×N SC RB RE 106. Usually, the minimum frequency domain allocation unit of data is RB 107. In the NR system, usually N symb =14 and N SC RB =12, and the number of RB 107 (N RB ) can be changed according to the bandwidth of the system transmission band. In the LTE system, usually N symb =7 and N SC RB =12, and N RB Can be changed according to the bandwidth of the system transmission band.

[0073] DCI can be sent within the first N OFDM symbols in a subframe. Typically, N = {1, 2, 3}, and the terminal can be configured with the number of symbols in which DCI can be sent from the base station via a high-layer signal. In addition, the base station can change the number of symbols in which DCI can be sent from the time slot for each time slot, depending on the amount of control information to be sent from the current time slot, and send information about the number of symbols to the terminal via a separate DL control channel.

[0074] In the NR or LTE system, scheduling information about DL data or UL data can be sent from the base station to the terminal through DCI. According to an embodiment, DCI can be defined according to various formats, and can depend on each format to indicate whether DCI is scheduling information for UL data (UL grant) or scheduling information for DL ​​data (DL grant), whether DCI is a compact DCI with control information of a small size, whether DCI is a fallback DCI, whether spatial multiplexing using multiple antennas is applied, and whether DCI is a power control DCI. For example, a DCI format (e.g., DCI format 1_0 of NR) as scheduling control information (DL grant) for DL ​​data may include one of the following control information.

[0075] -DCI format identifier: Identifier that identifies the received DCI format

[0076] - Frequency domain resource allocation: indicates the RBs allocated for data transmission

[0077] -Time domain resource allocation: indicates the time slots and symbols allocated for data transmission

[0078] - Virtual Resource Block (VRB) to PRB mapping: Indicates whether VRB mapping is applied

[0079] - Modulation and Coding Scheme (MCS): Indicates the modulation scheme used for data transmission and the size of the transport block (TB) which is the data to be sent

[0080] - New data indicator: Indicates whether the HARQ transmission is an initial transmission or a retransmission.

[0081] - Redundancy version: indicates the redundancy version of HARQ.

[0082] -HARQ process number: indicates the HARQ process number.

[0083] -PDSCH allocation information (downlink allocation index): indicates the number of PDSCH reception results (e.g., the number of HARQ-ACKs) to be reported to the base station by the terminal

[0084] - Transmit Power Control (TPC) Command for Physical UL Control Channel (PUCCH): Indicates the transmit power control command for PUCCH as the UL control channel

[0085] -PUCCH resource indicator: indicates the PUCCH resource used for HARQ-ACK reporting, including the reception result of the PDSCH configured via the corresponding DCI

[0086] -PUCCH transmission timing indicator (PDSCH-to-HARQ_feedback timing indicator): indicates the time slot or symbol information in which the PUCCH for HARQ-ACK reporting will be transmitted, including the reception result of the PDSCH configured via the corresponding DCI

[0087] After channel coding and modulation processing, DCI can be sent through PDCCH (or control information, hereinafter, used interchangeably) or enhanced PDCCH (EPDCCH) (or enhanced control information, hereinafter, used interchangeably). Hereinafter, the description of sending or receiving PDCCH or EPDCCH can be understood as the sending or receiving of DCI on PDCCH or EPDCCH, and PDSCH sending or receiving can be understood as DL data sending or receiving on PDSCH.

[0088] Typically, DCI is scrambled independently for each terminal, by a specific radio network temporary identifier (RNTI) (or terminal identifier (C-RNTI)), a cyclic redundancy check (CRC) is added, channel coded, and then configured as an independent PDCCH to be transmitted. In the time domain, the PDCCH is mapped and transmitted for the control channel transmission interval. The mapping position of the PDCCH in the frequency domain is determined by the identifier (ID) of each terminal, and the PDCCH can be transmitted through the transmission band of the entire system.

[0089] DL data may be transmitted through the PDSCH which is a physical channel for transmitting DL data. The PDSCH may be transmitted after a control channel transmission interval, and scheduling information such as a concrete mapping position or a modulation scheme in a frequency domain may be determined based on DCI to be transmitted through the PDCCH.

[0090] The base station notifies the terminal of the modulation scheme applied to the PDSCH to be transmitted and the size of the data to be transmitted (transport block size (TBS)) by configuring the modulation coding scheme (MCS) in the control information of the DCI. According to the embodiment, the MCS may consist of 5 bits, or may consist of bits less than or greater than 5 bits. The TBS corresponds to the size before the channel coding for error correction is applied to the data (transport block (TB)) to be transmitted by the base station.

[0091] The modulation schemes supported in the NR system are quadrature phase shift keying (QPSK), 16 quadrature amplitude modulation (QAM), 64QAM or 256QAM, and the corresponding modulation order (Qm) corresponds to 2, 4, 6 and 8. In other words, 2 bits per symbol can be transmitted in QPSK, 4 bits per symbol can be transmitted in 16QAM, 6 bits per symbol can be transmitted in 64QAM, and 8 bits per symbol can be transmitted in 256QAM. In addition, according to system modification, a modulation scheme of 256QAM or higher can be used.

[0092] In the NR system, UL / DL HARQ adopts an asynchronous HARQ method in which the data retransmission time is not fixed. Referring to DL, when HARQ NACK is fed back from the terminal regarding the data initially transmitted by the base station, the base station can freely determine the transmission time of the retransmitted data through a scheduling operation. The terminal buffers the data determined to be erroneous as a result of decoding the data received for the HARQ operation, and can then perform a combination with the data retransmitted from the base station. The HARQ ACK / NACK information of the PDSCH transmitted in the subframe nk can be transmitted from the terminal to the base station via the PUCCH or PUSCH in the subframe n.

[0093] According to an embodiment, in a 5G communication system such as NR, the value of k may be sent by being included in a DCI indicating or scheduling the reception of a PDSCH sent in a subframe nk, or may be configured to the terminal via a high-level signal. Here, the base station may configure one or more values ​​of k via a high-level signal, or may indicate a specific value of k via a DCI. The value of k may be determined depending on the HARQ-ACK processing capability of the terminal, that is, the minimum time required for the terminal to receive the PDSCH and generate and report the HARQ-ACK for the PDSCH. In addition, the terminal may be a predefined value or a default value until the value of k is configured.

[0094] The wireless communication system, method, and apparatus proposed in the embodiments of the present disclosure have been described based on the NR system, but the content of the present disclosure is not limited to the NR system and can be applied to various communication systems such as LTE, LTE-A, LTE-A-Pro, and 5G systems. In addition, the present disclosure is described based on a system and an apparatus for transmitting or receiving a signal by using an unlicensed frequency band, but the content of the present disclosure can also be applied to a system operating in a licensed frequency band.

[0095] Hereinafter, the high-layer signaling or high-layer signal in the present disclosure may be a method of transmitting a signal from a base station to a terminal by using a DL data channel of a physical layer or from a terminal to a base station by using an UL data channel of a physical layer, and may include a method of transmitting a signal via a radio resource control (RRC) signaling, a packet data convergence protocol (PDCP) signaling, or a medium access control (MAC) control element (CE). In addition, the high-layer signaling or high-layer signal may include system information commonly transmitted to multiple terminals, for example, a system information block (SIB).

[0096] In a system that performs communication in an unlicensed frequency band, a transmitting device (base station or terminal) that is to transmit a signal via the unlicensed frequency band may perform a channel access procedure (or LBT) for the unlicensed frequency band before transmitting the signal for performing communication, and according to the channel access procedure, when it is determined that the unlicensed frequency band is in an idle state, perform signal transmission by accessing the unlicensed frequency band. When it is determined that the unlicensed frequency band is not in an idle state according to the performed channel access procedure, the transmitting device cannot perform signal transmission.

[0097] The channel access process in the unlicensed band can be roughly divided into two types depending on whether the start time of the channel access process is fixed (frame-based equipment (FBE)) or variable (load-based equipment (LBE)). Here, in addition to the start time of the channel access process, FBE or LBE can also be determined based on whether the transmit / receive structure of the transmitting device has a cycle or does not have a cycle. The fixed start time of the channel access process may mean that the channel access process of the transmitting device can be periodically initiated according to a predefined cycle or a cycle declared or configured by the transmitting device. Another meaning may be that the transmit / receive structure of the transmitting device may have a cycle. The variable start time of the channel access process may mean that the start time of the channel access process of the transmitting device may be initiated at any time when the transmitting device wants to send a signal via the unlicensed band. Another meaning may be that the transmit / receive structure of the transmitting device may be configured not to have a cycle when necessary.

[0098] Hereinafter, a channel access procedure when a start time of a channel access procedure of a transmitting device is variable (LBE) (hereinafter, a service-based channel access procedure or a channel access procedure) will be described.

[0099] During the channel access process of an unlicensed band, the transmitting device can measure the signal received via the unlicensed band for a fixed time period or for a time calculated according to a predefined rule (for example, a time calculated via a random value selected at least by a base station or a terminal), and determine the idle state of the unlicensed band by comparing the strength of the received signal with a threshold value calculated in advance or according to a function for determining the magnitude of the received signal strength, a function including at least one variable including the channel bandwidth in which the signal to be transmitted is sent or the signal bandwidth and the strength of the transmission power.

[0100] For example, the transmitting device may measure the signal strength X microseconds (e.g., 25 microseconds) immediately before the time of transmitting the signal, and when the strength of the measured signal is less than a predefined or calculated threshold value T (e.g., -72 dBm), determine that the unlicensed band is in an idle state, and transmit the configured signal. Here, after the channel access process, the maximum possible time for continuous signal transmission may be limited according to the following: the maximum channel occupancy time defined for each country, region, and frequency band according to each unlicensed band; and may also be limited according to the type of transmitting device (e.g., base station or terminal, or master or slave). For example, in Japan, with respect to an unlicensed band determined to be in an idle state after performing a channel access process, a base station or terminal can occupy a channel in a 5 GHz unlicensed band and transmit a signal without having to perform an additional channel access process of a maximum time of 4 milliseconds.

[0101] In detail, when a base station or a terminal is to transmit a DL or UL signal in an unlicensed band, a channel access procedure that may be performed by the base station or the terminal may be divided into the following types.

[0102] - Type 1: After performing a channel access procedure for a variable time, a UL / DL signal is transmitted

[0103] - Type 2: After performing a channel access procedure for a fixed time, a UL / DL signal is transmitted

[0104] - Type 3: Transmitting UL / DL signals without performing a channel access procedure

[0105] A transmitting node (hereinafter, a base station or a terminal) that is to transmit a signal in an unlicensed band can determine a channel access procedure according to the type of the signal to be transmitted. In the following, for the convenience of description, it will be assumed that the transmitting node is a base station and the transmitting node and the base station can be used interchangeably to describe the present disclosure.

[0106] For example, when the base station is to transmit a DL signal including a DL data channel in an unlicensed frequency band, the base station may perform a channel access procedure of type 1. When the base station is to transmit a DL signal not including a DL data channel in an unlicensed frequency band, for example, when transmitting a synchronization signal or a DL control channel, the base station may perform a channel access procedure of type 2 and transmit the DL signal.

[0107] Here, the type of channel access procedure can be determined according to the transmission length of the signal to be sent in the unlicensed band or the length of the time or section used by occupying the unlicensed band. Generally, type 1 may require a longer time to perform the channel access procedure than performing the channel access procedure of type 2. Therefore, when a signal is to be sent for a time equal to or less than a short time period or reference time (e.g., X milliseconds or Y symbols), a channel access procedure of type 2 can be performed. On the other hand, when a signal is to be sent for a time equal to or greater than a long time period or reference time (e.g., X milliseconds or Y symbols), a channel access procedure of type 1 can be performed. In other words, different types of channel access procedures can be performed according to the time of using the unlicensed band.

[0108] When performing a channel access procedure of type 1 according to the above-mentioned at least one reference, the transmitting node may determine a channel access priority class according to a quality of service class identifier (QCI) of a signal to be transmitted in an unlicensed band, and perform the channel access procedure by using at least one of the configuration values ​​predefined for the channel access priority class as determined in Table 1. The following Table 1 is a table showing a mapping relationship between a channel access priority class and a QCI.

[0109] For example, QCI 1, 2, and 4 represent QCI values ​​for services of conversational voice, conversational video (real-time stream), and non-conversational video (buffered stream), respectively. When a signal for a service that is not mapped to a QCI in Table 1 is to be transmitted in an unlicensed band, the transmitting node may select a service and a QCI that is closest to the QCI of Table 1, and select a channel access priority class for this purpose.

[0110] [Table 1]

[0111] Channel access priority QCI 1 1，3，5，65，66，69，70 2 2，7 3 4，6，8，9 4 -

[0112] According to an embodiment, the deferment period (deferduration) according to the determined channel access priority p, the group CW_p of the value or size of the contention window, the minimum value CW_min,p and the maximum value CW_max,p of the contention window, and the maximum channel occupancy possible interval T_mcot,p can be determined via Table 2. Table 2 shows the above values ​​according to the channel access priority category in DL.

[0113] In other words, a base station that is to send a DL signal in an unlicensed band performs a channel access procedure on an unlicensed band for a time of at least T_f+m_p*T_sl. When a base station is to perform a channel access procedure of channel access priority category 3 (p=3), the size of the postponement period T_f+m_p*T_sl required to perform the channel access procedure can be configured by using m_p=3. Here, T_f is a value fixed to 16 microseconds, the first T_sl time should be in an idle state, and the base station may not perform the channel access procedure for the remaining time T_f-T_sl after the time T_sl in the time T_f. Here, even when the base station performs the channel access procedure for the remaining time T_f-T_sl, the result of the channel access procedure is not used. In other words, time T_f-T_sl is the time when the base station postpones performing the channel access procedure.

[0114] When it is determined that the unlicensed band is in an idle state for the entire time of m_p*T_sl, N=N-1. Here, when performing the channel access process, N is selected as any integer value between 0 and the value of the contention window CW_p. In channel access priority category 3, the minimum contention window value and the maximum contention window value are 15 and 63, respectively. When it is determined that the unlicensed band is in an idle state during the postponement period and the additional channel access process execution period, the base station can send a signal via the unlicensed band for time T_mcot,p (8 milliseconds). At the same time, Table 2 shows the channel access priority categories in DL. For convenience of description, the present disclosure will be described by using DL channel access priority categories, and the channel access priority categories of Table 2 can be reused for UL, or channel access priority categories for UL transmission can be defined for use.

[0115] [Table 2]

[0116]

[0117] The initial contention window value CW_p is the minimum value CW_min,p of the contention window. When the value N is selected, the base station performs a channel access procedure in the T_sl interval, and when it is determined via the channel access procedure performed in the T_sl interval that the unlicensed band is in an idle state, the value is changed to N=N-1. When N=0, the base station can send a signal via the unlicensed band for a maximum time T_mcot,p. When it is determined via the channel access procedure in the T-s1 interval that the unlicensed band is not in an idle state, the value of N does not change and the channel access procedure can be performed again.

[0118] The value of the contention window CW_p may be changed or maintained according to the ratio Z of NACK in the reception result (ACK / NACK) for DL ​​data transmitted or reported to the base station (received in the reference subframe or reference time slot) by at least one terminal receiving DL data transmitted via a DL data channel from a reference subframe or a reference time slot. Here, the reference subframe or the reference time slot may be determined as the DL signal transmission interval (or MCOT) most recently transmitted by the base station via the unlicensed band at the time when the base station initiates the channel access procedure, at the time when the base station selects the value of N to perform the channel access procedure, or immediately before the above two times.

[0119] Figure 2 is a diagram of a channel access procedure in an unlicensed band according to an embodiment.

[0120] refer to Figure 2 , at the time 270 when the base station initiates the channel access procedure, or at the time when the base station selects the value of N to perform the channel access procedure, or immediately before the above two times, the first time slot or subframe 240 of the channel occupation time (COT) 230 most recently transmitted by the base station via the unlicensed band may be defined as a reference time slot or reference subframe. Specifically, a subframe including at least the first time slot or subframe in which a signal is transmitted in the entire time slot or subframe in the COT 230 may be defined as a reference time slot or reference subframe. When the COT 230 starts after the first symbol of the time slot or subframe, the first subframe in which a signal is transmitted in the time slot or subframe and the entire subframe in which DL signal transmission starts may be defined as a reference time slot or reference subframe. When the proportion of NACKs in the reception results for DL ​​data sent or reported to the base station by at least one terminal receiving DL data sent via the DL data channel in a reference time slot or a reference subframe is equal to or greater than Z, the base station can perform the channel access process by determining the value or size of the contention window for the channel access process of the corresponding base station as a next contention window larger than the contention window used for the previous channel access process, that is, by increasing the contention window size.

[0121] When the base station is unable to receive a report on the reception result of the DL data channel sent from the first time slot or subframe, for example, when the time interval between the first subframe and the time 270 when the base station initiates the channel access process is equal to or less than n time slots or subframes (i.e., when the base station initiates the channel access process before the terminal is able to report the reception result of the DL data channel of the first subframe), the first frame of the most recent COT sent before COT230 becomes the reference subframe.

[0122] In other words, when the base station cannot receive the reception result for the DL data sent from the subframe 240 from the terminal at the time 270 when the base station initiates the channel access process, or at the time when the base station selects the value of N to perform the channel access process, or immediately before the above two times, the base station can determine the first subframe of the most recently transmitted COT as the reference subframe from the reception result of the pre-received DL data channel from the terminal. In addition, by using the reception result of the DL data received from the terminal regarding the DL data sent via the DL data channel in the reference subframe, the base station can determine the size of the contention window for the channel access process 270.

[0123] For example, when at least 80% of the reception results of the terminal for DL ​​data sent to the terminal via the DL data channel in the first subframe in the DL signal sent through the unlicensed frequency band are determined as NACK, the base station that sends the DL signal through a channel access process (for example, CW_p=15) configured via channel access priority category 3 (p=3) can increase the contention window from the initial value (CW_p=15) to the next contention window value (CW_p-=31).

[0124] When at least 80% of the reception results of the terminal are not determined as NACK, the base station can maintain the value of the contention window as the existing value, or change the value of the contention window to the initial value of the contention window. Here, the change of the contention window can be applied publicly to all channel access priority categories, or only to the channel access priority category used in the channel access process. From the reception result for determining the change in the size of the contention window (the reception result for DL ​​data sent or reported by the terminal to the base station regarding DL data sent via a DL data channel from a reference subframe or a reference time slot), a method for determining the reception result effective in determining the change in the size of the contention window, that is, a method for determining the Z value, is as follows.

[0125] In the case where the base station sends at least one codeword or TB to at least one terminal from a reference subframe or a reference time slot, the base station may determine the value of Z as the proportion of NACK in the reception result sent or reported by the terminal regarding the TB received from the reference subframe or the reference time slot. For example, when two codewords or two TBs are sent to one terminal from a reference subframe or a reference time slot, the base station receives or is reported the reception result of the DL data signal for the two TBs from the terminal. When the proportion of NACK in the two reception results (Z) is equal to or greater than a threshold value (e.g., Z=80%) predefined or configured between the base station or the terminal, the base station may change or increase the size of the contention window.

[0126] Here, when the terminal bundles the reception results of DL data of one or more subframes (e.g., M subframes) including the reference subframe or the reference time slot and reports or sends them to the base station, the base station can determine that the terminal has sent M reception results. Then, the base station can determine the value of Z as the ratio of NACK in the M reception results, and change, maintain or initialize the size of the contention window.

[0127] When the reference subframe is the reception result of the second time slot of two time slots configuring a subframe, the value of Z can be determined as the proportion of NACK in the reception results sent or reported by the terminal to the base station for the DL data received in the reference subframe (i.e., the second time slot) and the next subframe.

[0128] In addition, in the case where scheduling information or DCI for a DL data channel sent by a base station is sent in the same cell or frequency band as the cell or frequency band in which the DL data channel is sent, or in the case where scheduling information or DCI for a DL data channel sent by a base station is sent via an unlicensed band or in a cell or frequency band different from the cell in which the DL data channel is sent, when it is determined that the terminal does not send a reception result for the DL data received from a reference subframe or a reference time slot and when it is determined that the reception result for the DL data sent by the terminal is discontinuous transmission (DTX), NACK / DTX, or at least one of any states, the base station can determine the value of Z by determining the reception result of the terminal as NACK.

[0129] In addition, in the case of transmitting scheduling information or DCI for a DL data channel transmitted by the base station via a licensed frequency band, when determining that the reception result for the DL data transmitted by the terminal is at least one of DTX, NACK / DTX, or any state, the base station may not include the reception result of the terminal into the value of Z, that is, the reference value for changing the contention window. In other words, the base station may determine the value of Z while ignoring the reception result of the terminal.

[0130] In addition, in the case where the base station sends scheduling information or DCI for a DL data channel via a licensed frequency band, the base station can determine the value of Z while ignoring the reception results for DL ​​data for a reference subframe or reference time slot sent or reported by the terminal to the base station, and the reception results for DL ​​data when the base station does not actually send DL data (no transmission).

[0131] In the following, we will use Figure 3 A channel access procedure when a start time of a channel access procedure of a transmitting device is fixed (FBE) (hereinafter, a frame-based channel access procedure or a channel access procedure) is described.

[0132] Figure 3is a diagram of a channel access procedure in an unlicensed band according to another embodiment.

[0133] A device that performs a frame-based channel access process can periodically send or receive a signal according to a fixed frame period (FFP). Here, the FFP 300 can be declared or configured by a transmitting device (e.g., a base station) and can be configured from 1 millisecond to 10 milliseconds. Here, a channel access process (or clear channel access (CCA) 330, 333, and 336) for an unlicensed band can be performed immediately before the start of each frame period and for a fixed time or an observation time slot (such as the channel access process type 2 described above). When it is determined that the unlicensed band is in an idle state or an idle channel according to the result of the channel access process, the transmitting device can send or receive a signal for a maximum of 95% of the time of the FFP 300 (hereinafter, COT 310) without performing a separate channel access process. Here, the minimum 5% of the time of the FFP 300 is an idle period 320 in which a signal cannot be sent or received, and the channel access process can be performed within the idle period 320.

[0134] Compared with the service-based channel access process, the frame-based channel access process is relatively simple in performing the channel access process and can perform channel access in an unlicensed band. However, because the start time of the channel access process is fixed, the possibility of accessing an unlicensed band may be low compared with the service-based channel access process.

[0135] In the 5G system, it is necessary to flexibly define and operate the frame structure taking into account various services and requirements. For example, based on the requirements, the service can have different subcarrier spacings. The following equation 1 can be used to determine the method of supporting multiple subcarrier spacings in the current 5G communication system.

[0136] [Equation 1]

[0137] Δf=f 0 2 m

[0138] Here, f0 indicates the base subcarrier spacing of the system, and m represents a scaling factor of an integer. For example, when f0 is 15kHz, the subcarrier spacing set of the 5G communication system may include 3.75kHz, 7.5kHz, 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, and 480kHz. The available subcarrier spacing set may vary depending on the frequency band. For example, 3.75kHz, 7.5kHz, 15kHz, 30kHz, and 60kHz may be used in a frequency band less than or equal to 6GHz, and 60kHz, 120kHz, and 240kHz may be used in a frequency band equal to or greater than 6GHz.

[0139] According to an embodiment, the length of an OFDM symbol may vary according to the subcarrier spacing constituting the OFDM symbol. This is because the subcarrier spacing and the length of an OFDM symbol have an inverse relationship with each other. For example, when the subcarrier spacing is doubled, the symbol length is shortened by half; and when the subcarrier spacing is reduced by 1 / 2, the symbol length is doubled.

[0140] Figure 4 is a diagram of a DL and UL scheduling method and resource areas in an NR system according to an embodiment.

[0141] refer to Figure 4 , showing a resource region for transmitting a data channel in a 5G or NR communication system. The terminal monitors or searches for PDCCH 410 in a DL control channel (hereinafter, PDCCH) region (hereinafter, control resource set (CORESET) or search space (SS)) configured by a base station via a high-level signal. Here, the DL control channel region includes time resources 414 and frequency resources 412, wherein the time resources 414 may be configured in symbol units, and the frequency resources 412 may be configured in RB units or in groups of RBs.

[0142] When the terminal detects the PDCCH 410 in the time slot i 400, the terminal obtains the DCI transmitted via the detected PDCCH 410. Through the received DCI, the terminal can obtain scheduling information about the DL data channel or the UL data channel. In other words, the DCI may include at least resource region (or PDSCH transmission region) information for receiving the DL data channel (hereinafter, PDSCH) transmitted from the base station by the terminal, or resource region information allocated from the base station to the terminal to transmit the UL data channel (PUSCH).

[0143] An example in which a terminal is scheduled with UL data channel (PUSCH) transmission will be described. Upon receiving DCI, the terminal may obtain a slot index or offset information K for receiving PUSCH via DCI, and determine the PUSCH transmission slot index. For example, the terminal may determine that PUSCH is scheduled to be sent in slot i+K 405 based on slot i 400 in which PDCCH 410 is received, through the received offset information K. Here, the terminal may determine the PUSCH start symbol or time in slot i+K 405 or slot i+K 405 based on the CORESET in which PDCCH 410 is received, through the received offset information K.

[0144] In addition, the terminal may obtain information about the PUSCH transmission time-frequency resource region 440 in the PUSCH transmission time slot 405 from the DCI. The PUSCH transmission frequency resource region information 430 may include physical resource blocks (PRBs) or group unit information of PRBs. At the same time, the PUSCH transmission frequency resource region information 430 may be a region including an initial UL bandwidth (BW) or an initial UL bandwidth part (BWP) determined or configured by the terminal via an initial access procedure. When the terminal is configured with a UL BW or UL BWP via a higher layer signal, the PUSCH transmission frequency resource region information 430 may be a region included in the UL BW or UL BWP configured via the higher layer signal.

[0145] According to an embodiment, the PUSCH transmission time resource region information 425 may be information of a symbol or a group unit of a symbol, or may be information indicating absolute time information. The PUSCH transmission time resource region information 425 may be included in the DCI as a field or value by representing it in combination with the PUSCH transmission start time or symbol and the PUSCH length or the PUSCH end time or symbol. Here, the PUSCH transmission time resource region information 425 may be included in the DCI as a field or value representing each of the PUSCH transmission start time or symbol and the PUSCH length or the PUSCH end time or symbol. The terminal may send PUSCH from the PUSCH transmission resource region 440 determined via the DCI.

[0146] In a 5G communication system, it is possible to indicate via a slot format indicator (SFI) whether each of the OFDM symbols configuring a slot is a DL symbol, a UL symbol, or a flexible symbol, so as to dynamically change the DL signal transmission and the UL signal transmission parts in a time division duplex (TDD) system. Here, a symbol indicated as a flexible symbol represents a symbol that is neither a DL symbol nor a UL symbol, or a symbol that can be changed to a DL or UL symbol according to terminal-specific control information or scheduling information. Here, a flexible symbol may include gap protection required for a switching process from DL to UL.

[0147] The SFI is sent to multiple terminals simultaneously via a terminal group (or cell) common control channel. In other words, the SFI is CRC-scrambled by another identifier (e.g., SFI-RNTI) different from the C-RNTI, and then sent via the PDCCH. According to an embodiment, the SFI may include information about N time slots, wherein the value of N may be an integer or a natural number greater than 0, or may be a value in a set of predefined values ​​(such as 1, 2, 5, 10, and 20) configured by the base station to the terminal via a high-level signal. In addition, the size of the SFI may be configured by the base station to the terminal via a high-level signal. An example of a time slot format that the SFI may indicate is shown in Table 3.

[0148] [Table 3]

[0149]

[0150] In Table 3, D represents DL, U represents UL, and X represents flexible symbols. The total number of slot formats that can be supported in Table 3 is 256. In the current NR system, the maximum size of the SFI information bit is 128 bits, and the SFI information bit can be a value that can be configured by the base station to the terminal via a higher layer signal (e.g., dci_PayloadSize).

[0151] According to an embodiment, the SFI information may include time slot formats for multiple service cells and may be distinguished via a service cell ID. In addition, with respect to each service cell, a combination of SFIs for one or more time slots (time slot format combination) may be included. For example, when the size of the SFI information bit is 3 bits and is configured by an SFI for one service cell, the 3-bit SFI information may configure a total of 8 SFIs or SFI combinations (hereinafter, SFIs), and the base station may indicate one of the 8 SFIs via terminal group common control information (group common DCI, referred to as SFI information).

[0152] According to an embodiment, at least one of the 8 SFIs may be configured by SFIs for a plurality of time slots. For example, Table 4 shows an example of 3-bit SFI information configured by the time slot format of Table 3. Five pieces of information (slot format combination IDs 0, 1, 2, 3, and 4) of the SFI information are SFIs for one time slot, and the remaining three pieces of information are information about SFIs for four time slots (slot format combination IDs 5, 6, and 7), which are sequentially applied to the four time slots.

[0153] [Table 4]

[0154] Slot format combination ID Time slot format 0 0 1 1 2 2 3 19 4 9 5 0 0 0 0 6 1 1 1 1 7 2 2 2 2

[0155] The terminal receives configuration information for detecting SFI information on the PDCCH via a high-layer signal, and detects SFI according to the configuration. For example, the terminal is configured with a CORESET configuration for detecting SFI information, a search space configuration, RNTI information for CRC scrambling of the DCI in which the SFI information is sent, and a period and offset information of the search space via a high-layer signal.

[0156] Figure 5 is a graph of channel occupancy time according to an embodiment.

[0157] Figure 5 A case is shown in which the terminal needs to detect PDCCH regions 520, 522, and 524 of SFI information, and in which the period of the PDCCH regions 520, 522, and 524 is 2 time slots. In other words, the terminal detects the DCI scrambled by the SFI identifier (hereinafter, SFI-RNTI) CRC from the PDCCH regions 520, 522, and 524 in time slots n 500, n+2502, and n+4 504 according to the configured PDCCH regions 520, 522, and 524 and their periods, and can obtain the SFI for two time slots via the detected DCI. Here, the detected DCI may include SFI information for two or more time slots, and the number of time slots in the SFI may be configured via a high-level signal. Configuration information about the number of time slots in the SFI may be included in the same high-level signal as the high-level signal that configures the SFI information. For example, in Figure 5 , the terminal obtains SFI information 510 and 511 for slots n 500 and n+1 501 in the PDCCH region 520 of slot n 500. Here, SFI information 510, 511, 512, 513, and 514 represent the format of Table 3.

[0158] When the SFI information is transmitted in an unlicensed band, specifically, when the SFI information includes SFIs for a plurality of time slots, the base station may not be able to determine the SFI information for at least one time slot according to channel access of the unlicensed band. Figure 5 In the present invention, when the base station performs a channel access procedure on the unlicensed band before time slot n 500 and occupies and uses the channel from time slot n 500 to time slot n+4 504 by determining an idle channel through the channel access procedure, the base station cannot determine the SFI of time slot n+5 505 because the result of the channel access procedure in the unlicensed band in time slot n+5 505 is unpredictable. In other words, when the SFI information 514 and 515 for time slot n+4 504 and time slot n+5 505 are transmitted in the PDDCH 524, the base station needs a method of determining the SFI information of time slot n+5 505.

[0159] In addition, the terminal needs a method for determining whether the base station is a base station that performs a frame-based channel access procedure or a base station that performs a service-based channel access procedure. In addition, when the base station is a base station that performs a frame-based channel access procedure, the terminal needs to additionally receive information about FFP, COT, etc. declared or configured by the base station from the base station. Therefore, in the present disclosure, a method for determining information such as COT via SFI in an unlicensed band, and a method for sending or receiving a signal via the determined SFI information will be described.

[0160] In the present disclosure below, the case where the base station sends a DL signal to the terminal via an unlicensed band and the case where the terminal sends a UL signal to the base station via an unlicensed band will be described together. However, the content proposed in the present disclosure can be applied identically or partially modified to the case where the terminal sends a UL signal to the base station via an unlicensed band or the case where the base station sends a DL signal to the terminal via an unlicensed band. Therefore, a detailed description of the sending and receiving of DL signals will be omitted. In addition, in the present disclosure, a case where a DL data information (codeword or TB) or UL data information is sent or received between a base station and a terminal will be described. However, the content proposed in the present disclosure can also be applied to the case where the base station sends a DL signal to multiple terminals or the case where multiple codewords or TBs are sent or received between a base station and a terminal. In addition, the content proposed in the present disclosure can also be applied to the following case: wherein the base station or the terminal sends or receives a signal in units of code block groups by grouping one or more code blocks configuring a TB.

[0161] The methods and apparatus proposed in the following embodiments of the present disclosure are not applied to each embodiment in a limited manner, but can be used for methods and apparatus for determining SFI information by using a combination of all or some of the embodiments proposed in the present disclosure. In addition, in the embodiments of the present disclosure, a case where a base station sends SFI information to a terminal via DCI and the terminal uses the received SFI information will be described, but the embodiment can also be applied to a case where the terminal sends SFI information to a base station via uplink control information (UCI) and the base station uses the received SFI information. In addition, in the embodiments of the present disclosure, a base station and a terminal operating in an unlicensed band will be described, but the methods and apparatus proposed in the embodiments of the present disclosure can also be applied to base stations and terminals operating not only in an unlicensed band but also in a licensed band or a shared spectrum.

[0162] In addition, the SFI information described below in the embodiments of the present disclosure is assumed to be SFI information sent to a specific terminal or a terminal in a specific group via PDCCH, but SFI information (or UL-DL configuration information) sent to the terminal via a high-layer signal may also be used.

[0163] In addition, in the following embodiments of the present disclosure, the case where the terminal receives a DL data channel (PDSCH) from the base station will be mainly described, but the embodiments proposed in the present disclosure can also be applied to the case where the terminal sends a UL data channel (PUSCH) to the base station. In addition, the case where SFI for multiple time slots is sent simultaneously will be described, but the embodiments proposed in the present disclosure can also be applied to the case where SFI for one time slot is sent.

[0164] In addition, in the following embodiments of the present disclosure, the SFI indicating whether the symbol included in one or more time slots is a UL symbol, a DL symbol, or a flexible symbol can be used interchangeably with the SFI or time slot configuration information. In addition, since the unlicensed band channel occupancy time of the base station or terminal can be notified via the SFI, the SFI can also be referred to as channel occupancy time information.

[0165] [First embodiment]

[0166] According to an embodiment, a method in a base station and a terminal operating in an unlicensed frequency band, by which the terminal determines whether a channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure.

[0167] A base station using a frame-based channel access procedure can notify the terminal that the channel access procedure of the base station is a frame-based channel access procedure via the following method. Here, when the terminal does not receive information about the channel access procedure of the base station from the base station, the terminal can determine that the base station is using a service-based channel access procedure.

[0168] Method 1-1: Send via the Master Information Block (MIB) of PBCH

[0169] Method 1-1 will now be described in detail. The base station may transmit to the terminal via the MIB transmitted through the PBCH whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure.

[0170]

[0171] For example, the terminal can be notified whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure by adding a 1-bit indicator to the MIB or by using one of the existing MIB bit strings. The terminal can then determine the channel access procedure of the base station and perform DL signal reception or UL signal transmission according to the determined channel access procedure. For example, when it is determined that the channel access procedure of the base station is a frame-based channel access procedure, the terminal can send a UL signal (e.g., PRACH) by using the channel access procedure used in the frame-based channel access procedure (e.g., channel access procedure type 2). Here, the terminal can determine whether UL signal transmission is possible.

[0172] Method 1-2: Send via System Information Block (SIB)

[0173] Method 1-2 will now be described in detail. The base station can send to the terminal via system information that is commonly sent to multiple terminals whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure. In other words, the terminal can be notified of whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure via the PDSCH sent by the DCI scrambled by the system information RNTI (SI-RNTI). Here, the channel access procedure of the base station can be sent via SIB1 (or RMSI) that is sent first or via SIBx (here, x is a natural number other than 1) that includes configuration information related to unlicensed band transmission / reception.

[0174] For example, whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure can be transmitted to the terminal via an additional field for SIB1 as follows.

[0175]

[0176] As another example, whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure can be sent to the terminal via the following additional field for SIB1. According to an embodiment, when the value of this field is true, the channel access procedure of the base station is a frame-based channel access procedure; and when the value is false, the channel access procedure of the base station is a service-based channel access procedure.

[0177]

[0178] As another example, whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure can be sent to the terminal via the following additional field for SIB1. According to an embodiment, when the value of this field is enabled, the channel access procedure of the base station is a frame-based channel access procedure; and when the value is false, the channel access procedure of the base station is a service-based channel access procedure.

[0179]

[0180] Then, the terminal can determine the channel access procedure of the base station, and perform DL signal reception or UL signal transmission according to the determined channel access procedure. For example, when it is determined that the channel access procedure of the base station is a frame-based channel access procedure, the terminal can send a UL signal (e.g., PRACH) by using the channel access procedure used in the frame-based channel access procedure (e.g., channel access procedure type 2). Here, the terminal can determine whether UL signal transmission is possible.

[0181] Method 1-3: Transmission via Random Access Response (RAR) Grant

[0182] Methods 1-3 will now be described in detail. The base station may send to the terminal whether its channel access procedure is a frame-based channel access procedure or a service-based channel access procedure through a RAR grant that schedules msg3 PUSCH transmission as one of the response messages regarding the initial access procedure of the terminal.

[0183] Table 5 shows the RAR grant field information and its size. For example, as shown in Table 5, the base station may send to the terminal via an additional field for the RAR grant whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure.

[0184] [Table 5]

[0185] RAR Permission Field Number of bits Frequency Hopping Flag 1 Msg3 PUSCH frequency resource allocation 14 Msg3 PUSCH time resource allocation 4 MCS 4 TPC command for Msg3 PUSCH 3 CSI Request 1 Channel access scheme 1

[0186] After receiving the RAR grant, the terminal can determine the channel access procedure of the base station and perform DL signal reception or UL signal transmission according to the determined channel access procedure. For example, when it is determined that the channel access procedure of the base station is a frame-based channel access procedure, the terminal can send a UL signal (e.g., Msg3 PUSCH) by using the channel access procedure used in the frame-based channel access procedure (e.g., channel access procedure type 2). Here, the terminal can determine whether UL signal transmission is possible.

[0187] Method 1-4: Send via RRC signaling

[0188] Methods 1-4 will now be described in detail. The base station may send to the terminal via a high-layer signal whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure. For example, the base station may send a 1-bit field to the terminal by adding a 1-bit field to a high-layer signal including configuration information related to unlicensed band transmission / reception as in method 1-2.

[0189] Then, the terminal can determine the channel access procedure of the base station, and perform DL signal reception or UL signal transmission according to the determined channel access procedure. For example, when it is determined that the channel access procedure of the base station is a frame-based channel access procedure, the terminal can send UL signals (e.g., PUCCH, PUSCH) by using the channel access procedure used in the frame-based channel access procedure (e.g., channel access procedure type 2). Here, the terminal can determine whether UL signal transmission is possible.

[0190] When a service-based channel access procedure is predefined with the terminal as the default channel access procedure of the base station, the base station can notify the terminal of the channel access procedure of the base station only when using the frame-based channel access procedure. Here, when the terminal does not receive information about the channel access procedure of the base station from the base station, the terminal can determine that the base station is using the service-based channel access procedure. Here, even when a service-based channel access procedure is not predefined with the terminal as the default channel access procedure of the base station, the terminal can determine that the base station is using the service-based channel access procedure when it does not receive information about the channel access procedure of the base station from the base station.

[0191] [Second embodiment]

[0192] In an embodiment, a method in a base station and a terminal operating in an unlicensed frequency band will be described, by which the base station sends frame-based channel access process configuration information including configuration information of at least one of FFP, COT and a fixed frame start time slot offset, and when the channel access process of the base station is a frame-based channel access process, the terminal that receives the configuration information determines the fixed frame structure of the base station.

[0193] First, the FFP information of the base station may be sent to the terminal via the following method.

[0194] Method 2-1: Sending FFP of a base station by using TDD UL-DL mode information

[0195] Method 2-1 will now be described in detail. Through the above-mentioned first embodiment, the base station can send to the terminal whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure. When receiving or determining that the channel access procedure of the base station is a frame-based channel access procedure, the terminal can determine the FFP of the base station via the TDD-UL-DL-Pattern information sent through SIB1 or the TDD-UL-DL-SlotConfig information sent through the RRC signal.

[0196] A method of determining the FFP of the base station via the TDD-UL-DL-Pattern information transmitted through SIB1 is as follows. An example of the TDD-UL-DL-Pattern information transmitted through SIB1 is as follows.

[0197]

[0198] When receiving or determining that the channel access procedure of the base station is a frame-based channel access procedure, the terminal may determine the value of dl-UL-TransmissionPeriodicity sent via mode 1 as FFP, which mode 1 is sent via TDD-UL-DL-Pattern information. When the TDD-UL-DL-Pattern information includes both mode 1 and mode 2, the terminal may determine the sum of dl-UL-TransmissionPeriodicity of mode 1 and dl-UL-TransmissionPeriodicity of mode 2 as FFP. Here, the value of dl-UL-TransmissionPeriodicity is an example and may vary as follows according to the value of FFP.

[0199]

[0200] A method of determining the FFP of the base station via the TDD-UL-DL-SlotConfig information transmitted through the RRC signal is as follows. An example of the TDD-UL-DL-SlotConfig information transmitted through the RRC signal is as follows.

[0201]

[0202] When receiving or determining that the channel access process of the base station is a frame-based channel access process, the terminal can determine the FFP via the time slot format information sent through the TDD-UL-DL-SlotConfig information. In detail, the TDD-UL-DL-SlotConfig information is the time slot format information about the time slot within a 10 millisecond period, that is, the terminal indicates or configures whether the corresponding time slot is a time slot configured only by DL symbols (allDownlink), a time slot configured only by UL symbols (allUplink), or a time slot configured by DL symbols and UL symbols (explicit). Here, the terminal can determine that the time slot whose time slot format is not indicated via the TDD-UL-DL-SlotConfig information is a flexible time slot.

[0203] Therefore, the base station can send the FFP information of the base station to the terminal by using the time slot format information sent via the TDD-UL-DL-SlotConfig information. For example, the base station can send the FFP information to the terminal via the TDD-UL-DL-SlotConfig information, by indicating the first time slot (or the first symbol in the first time slot) where the FFP starts - that is, the first time slot of each FFP - as a DL time slot (or indicating at least the Ath symbol (e.g., the first symbol) of the corresponding time slot as a DL symbol), and by indicating the last time slot of the FFP or the Bth symbol (e.g., the last symbol) of the last time slot as a flexible time slot or a flexible symbol.

[0204] Will refer to Figure 5 This is described in detail. Figure 5 An embodiment in which the subcarrier spacing is 15 kHz and the FFP 550 of the base station is 5 milliseconds is shown. The base station can indicate or configure the slot format of the slot index n slot and the slot index n+5 slot as the first slot of the FFP to the terminal via the TDD-UL-DL-SlotConfig information as a DL slot. Here, the base station can indicate or configure to the terminal that the first symbol 520 of the slot index n slot and the first symbol 525 of the slot index n+5 slot as the first slot of the FFP are DL symbols.

[0205] Here, the base station may indicate or configure the slot formats 511 to 514 of the slots 501 to 504 in the FFP by including the first slot of the FFP, but should not indicate the slot format of the last slot 504 of the FFP, or the slot format after the last B slot or the last slot 504 of the FFP. In other words, the base station may indicate that the slot format of at least the last symbol of the FFP is flexible, so that the terminal determines the FFP of the base station by using the slot format information. As another example, when the subcarrier spacing is 15kHz and the FFP of the base station is 10 milliseconds, the base station may indicate or configure the slot formats of the slot index 0 slot and the slot index 9 slot to the terminal via the TDD-UL-DL-SlotConfig information as DL slots and flexible slots, respectively. Here, indicating or configuring the slot format of the slot index 9 slot to the terminal as a flexible slot may indicate that the slot format information for the slot index 9 slot is not sent to the terminal.

[0206] Method 2-2: Sending FFP information via new higher layer signaling

[0207] Method 2-2 will now be described in detail. Through the above-mentioned first embodiment, the base station can send to the terminal whether the channel access procedure of the base station is a frame-based channel access procedure or a service-based channel access procedure. When receiving or determining that the channel access procedure of the base station is a frame-based channel access procedure, the terminal can receive the FFP of the base station via SIB1 (or SIBx, where x is a natural number other than 1) or RRC signaling.

[0208]

[0209] Then, the terminal can determine the FFP of the base station, and perform DL signal reception or UL signal transmission according to the determined FFP. For example, when it is determined that the channel access process of the base station is a frame-based channel access process, the terminal can transmit a UL signal (e.g., PUCCH or PUSCH) by using the channel access process used in the frame-based channel access process (e.g., channel access process type 2) during the COT of the FFP of the base station. Here, the terminal can determine whether UL signal transmission is possible.

[0210] The offset information for indicating the position of the time slot or symbol where the FFP of the base station starts may be transmitted to the terminal via the following method.

[0211] Method 2-3: Sending FFP of the base station using a fixed time period

[0212] Method 2-3 will now be described in detail. The time slot or symbol at which the FFP indicated or configured via the above method 2-1 or 2-2 starts can be determined by using a specific time period value. For example, it can be assumed that the FFP indicated or configured via method 2-1 or 2-2 starts assuming a fixed period of X milliseconds. In other words, the terminal can determine that the FFP starts from the following time slot: a time slot in which the result of the modulo operation with respect to the X period and the FFP indicated or configured via method 2-1 or 2-2 is 0, or a time slot in which the remainder between the FFP and the X period is 0.

[0213] Method 2-4: Sending FFP information via new higher layer signaling

[0214] Method 2-4 will now be described in detail. The time slot or symbol at which the FFP starts, indicated or configured via the above method 2-1 or 2-2, can be determined by using a specific reference time. Here, the reference time or offset information indicating the difference between the time slot at which the FFP starts and the reference time can be sent to the terminal via SIB or RRC signaling. The reference time or offset can be based on the system frame number (SFN) 0 or on the following time slot: in this time slot, a CORESET with the lowest CORESET index (e.g., CORESET index #0) configured to the terminal to search for PDCCH is sent; or in this time slot, a synchronization signal used by the terminal to receive a synchronization signal from the base station and obtain synchronization is sent.

[0215] The COT information in the FFP of the base station may be sent to the terminal via the following method.

[0216] Method 2-5: Determine the COT by using TDD UL-DL mode information.

[0217] Method 2-5 will now be described in detail. The base station may send the FFP of the base station to the terminal via the above-mentioned method 2-1 or 2-2. Here, the base station may send the COT of the base station to the terminal by using the time slot format information of the time slot in the FFP of the base station. For example, the base station may send the time slot format information of at least one of the DL time slot, UL time slot, or time slot configured by at least one DL or UL symbol to be used as the COT in the FFP for a time (hereinafter, symbol or time slot), and the terminal that receives the time slot format information may determine that the time slot indicated by the time slot format information of at least one of the DL time slot, UL time slot, or time slot configured by at least one DL or UL symbol in the FFP of the base station is the COT of the base station. Here, the base station sends the time slot format information of at least one of the DL time slot, UL time slot or time slot configured by at least one DL or UL symbol of the first time slot or the Ath symbol (e.g., the first symbol) of the first time slot in the symbol or time slot to be used as the COT in the FFP; and the last time slot of the COT or the Bth symbol of the last time slot (e.g., the last symbol) or the previous symbol thereof. Upon receiving the time slot format information, the terminal can determine the time slot indicated by the time slot format information of at least one of the DL time slot, UL time slot or time slot configured by at least one DL or UL symbol within the FFP of the base station, and determine the first symbol to the last symbol of the FFP in which the time slot format is indicated as the COT of the base station.

[0218] Method 2-6: Determine COT by using subcarrier spacing and FFP

[0219] Method 2-6 will now be described in detail. The base station may send the FFP of the base station to the terminal via method 2-1 or 2-2. Here, the terminal may determine the COT of the base station by using the determined FFP of the base station. For example, the terminal may determine the COT of the base station by using the ratio of the COT in the FFP predefined according to the regulation or configured by the base station. For example, when the maximum COT is limited to up to Z% of the FFP, the terminal may determine the FFP determined via method 2-1 or 2-2 according to equation 2.

[0220] [Equation 2]

[0221] COT=FFP*Z / 100[ms]

[0222] Here, the COT may be expressed in units of slots or symbols, and the maximum slot or symbol not exceeding the COT calculated according to Equation 2 may be determined as the COT. For example, when the FFP is 10 milliseconds and Z=95%, the COT may be determined to be 9.5 milliseconds via Equation 2. When the COT is converted in units of slots and / or symbols, the COT corresponds to 9 slots and 7 symbols based on a subcarrier spacing of 15 kHz. Via Equation 2, the terminal may determine the idle period of the base station by using the difference between the FFP and the COT.

[0223] By using the subcarrier spacing and FFP, the COT may be as indicated in Table 6. Here, the subcarrier spacing is the lowest subcarrier spacing among the subcarrier spacings configured to the terminal, or the subcarrier spacing configured in the channel, DL BWP, or UL BWP configured to perform a frame-based channel access procedure. Here, the subcarrier spacing used to determine the COT may be predefined between the base station and the terminal, or may be indicated or configured to the terminal by the base station via a high-layer signal, and the subcarrier spacing information may be transmitted by being included in the following high-layer signal: a high-layer signal indicating or configuring the transmission / reception configuration of the unlicensed band, or a high-layer signal indicating or configuring the channel occupancy method based on the frame structure. The subcarrier spacing information may be the subcarrier spacing information included in the TDD-UL-DL information of method 2-1 or 2-2, or the subcarrier spacing information included in the configuration information about the SFI information. Here, the number of symbols in the COT is the number of symbols that can be included in the COT starting from the first symbol of the time slot immediately after the number of time slots in the COT of Table 6. As described above, the terminal may determine the COT of the base station by using the subcarrier spacing and the FFP information via Equation 2 or Table 6.

[0224] [Table 6]

[0225]

[0226] Method 2-7: Sending FFP information via new high-level signal

[0227] Method 2-7 will now be described in detail. The COT information in the FFP indicated or configured via the above-mentioned method 2-1 or 2-2 or the slot and / or symbol information included in the COT may be transmitted to the terminal via SIB or RRC signaling.

[0228] However, the method of obtaining the COT information in the FFP of the base station is only an example and is not limited to this. The terminal can not only determine the COT information via SIB or high-layer signaling, but also determine the COT of the base station in the FFP through the SFI sent to the terminal via PDCCH. For example, by indicating the time slot format information about the symbols and / or time slots included in the COT of the base station via the SFI sent via PDCCH, via DL and / or UL symbols or time slots, the base station can notify the terminal of the COT of the base station. In other words, upon receiving the SFI information sent via PDCCH, the terminal can determine that the symbols and / or time slots indicated by the DL and / or UL symbols or time slots in the SFI information are the COT of the base station.

[0229] [Third embodiment]

[0230] In an embodiment, a method for a base station and a terminal operating in an unlicensed frequency band will be described, by which the terminal determines whether the base station occupies a channel in an FFP; or by which the terminal determines whether it is possible to initiate UL signal transmission of the terminal in the COT in the FFP of the base station when the channel access process of the base station is a frame-based channel access process.

[0231] As described above, when a frame-based channel access procedure is performed, the time to initiate the channel access procedure for the unlicensed band is fixed to immediately before the start of the FFP. In other words, when a base station that has performed a channel access procedure for an unlicensed band immediately before the start of the FFP determines that the unlicensed band is not an idle band, the base station cannot send a signal in the FFP. In this case, because the base station does not access the unlicensed band, the terminal should not send a UL signal in the FFP. In other words, the terminal can determine whether to perform UL signal transmission based on the channel access of the base station in each FFP. The terminal can determine the channel access of the base station via the following method.

[0232] Method 3-1: Whether PDCCH DMRS is received

[0233] Method 3-1 will now be described in detail. When it is indicated or determined via the above-mentioned embodiment that the base station is performing a frame-based channel access process, information such as the FFP, COT, etc. of the base station may be indicated to the terminal or the terminal may receive information such as the FFP, COT, etc. of the base station. The terminal may search for the PDCCH sent by including the first symbol in which the FFP of the base station is initiated to determine the channel access of the base station. Here, determining the channel access of the base station by searching the PDCCH means that when the terminal detects or receives the DMRS sent for channel estimation and decoding of the PDCCH, the terminal determines that the base station has accessed the channel in the FFP. In other words, when the terminal detects the DMRS of the PDCCH, the terminal determines that the base station has accessed the channel in the FFP; and when the terminal does not detect the DMRS, the terminal determines that the base station has not accessed the channel in the FFP.

[0234] When the channel access of the base station is determined by detecting the DMRS of the PDCCH as in method 3-1, the DMRS of the PDCCH sent by the CORESET with the lowest CORESET index in the CORESET where the terminal performs PDCCH detection in the currently activated BWP can be detected. Here, when the channel access of the base station is determined by detecting the DMRS of the PDCCH, the DMRS of the PDCCH sent from a specific CORESET (for example, CORESET#0) can be detected. When the terminal determines via method 3-1 that the base station cannot perform unlicensed band channel access in FFP, the terminal does not perform scheduled or configured UL signal transmission in FFP. When the terminal determines via method 3-1 that the base station has accessed an unlicensed band channel in FFP, the terminal can perform scheduled or configured UL signal transmission in FFP.

[0235] Here, when the terminal detects DCI for scheduling DL signal reception and / or UL signal transmission in the fixed frame part and DL signal reception and / or UL signal transmission are performed in the fixed frame part, the terminal can perform DL signal reception and / or UL signal transmission regardless of the DMRS detection of the PDCCH. In this case, the terminal may not perform operations other than DL signal reception and / or UL signal transmission scheduled via DCI (e.g., UL transmission without permission or configuration). In other words, in the above case, the terminal can only perform DL signal reception and / or UL signal transmission scheduled via DCI.

[0236] Via method 3-2, when the DL or UL scheduled DCI reception for determining that the base station accesses the unlicensed band in the FFP and the DL signal reception and / or UL signal transmission scheduled by the received DCI are performed within the same FFP, the terminal can determine that the base station has accessed the unlicensed band channel.

[0237] Method 3-2: Whether DCI is received

[0238] Method 3-2 will now be described in detail. When it is indicated or determined via the above-mentioned embodiment that the base station is performing a frame-based channel access process, information such as the FFP, COT, etc. of the base station may be indicated to the terminal or the terminal may receive information such as the FFP, COT, etc. of the base station. The terminal may search for a PDCCH transmitted by including a first symbol in which the FFP of the base station is initiated to determine the channel access of the base station. Here, the channel access indication of the base station is determined by searching the PDCCH, and when the terminal detects or receives a DCI indicating or scheduling DL signal reception and / or UL signal transmission, it is determined that the base station has accessed the channel in the FFP. In other words, when the terminal receives a DCI that schedules DL signal reception or UL signal transmission, the terminal determines that the base station has accessed the channel in the FFP, and when the terminal does not receive a DCI that schedules DL signal reception or UL signal transmission, the terminal can determine that the base station has not accessed the channel in the FFP.

[0239] When the terminal determines via method 3-2 that the base station cannot perform unlicensed band channel access in the FFP, the terminal does not perform scheduled or configured UL signal transmission in the FFP. When the terminal determines via method 3-2 that the base station has accessed an unlicensed band channel in the FFP, the terminal can perform scheduled or configured UL signal transmission in the FFP. Here, even when the terminal determines via method 3-2 that the base station has accessed an unlicensed band channel in the FFP, when the symbol or time slot for performing DL signal reception and / or UL signal transmission is not included in the same FFP as the symbol or time slot for detecting DCI, DL signal reception and / or UL signal transmission may not be performed. In other words, when the reception of the symbol or time slot of the DL or UL scheduled DCI received by the terminal in the FFP via method 3-2 is within the same FFP as the DL signal reception and / or UL signal transmission scheduled via DCI, the terminal can perform DL signal reception and / or UL signal transmission scheduled via DCI. Here, the terminal may not perform operations other than DL signal reception and / or UL signal transmission scheduled via DCI (eg, UL transmission without permission or configuration).

[0240] Method 3-3: Whether SFI is received

[0241] Method 3-3 will now be described in detail. When indicating or determining that the base station is performing a frame-based channel access process via the above-mentioned embodiment, information such as the FFP, COT, etc. of the base station may be indicated to the terminal or the terminal may receive information such as the FFP, COT, etc. of the base station. The terminal may search for a PDCCH transmitted by including the first symbol in which the FFP of the base station is initiated to determine the channel access of the base station. Here, determining the channel access of the base station by searching the PDCCH means that when a DCI transmitted to the terminal through its time slot format information is detected or received via the PDCCH, the terminal determines that the base station has accessed the channel in the FFP. Here, the DCI transmitted through its time slot format information may be transmitted from a symbol other than the first symbol in which the FFP of the base station is initiated, but the embodiment is not limited to including the first symbol. In other words, when the terminal receives the DCI transmitted through its time slot format information, the terminal determines that the base station has accessed the channel in the FFP; and when the terminal does not receive the DCI transmitted through its time slot format information, the terminal determines that the base station has not accessed the channel in the FFP.

[0242] When the terminal determines via method 3-3 that the base station cannot perform unlicensed band channel access in the FFP, the terminal does not perform scheduled or configured UL signal transmission in the FFP. When the terminal determines via method 3-3 that the base station has accessed an unlicensed band channel in the FFP, the terminal may perform scheduled or configured UL signal transmission in the FFP. Here, even when the terminal determines via method 3-3 that the base station has not accessed an unlicensed band channel in the FFP, when the symbol or time slot used to receive DL or UL scheduled DCI from the base station in the FFP is in the same FFP as the DL signal reception and / or UL signal transmission scheduled via DCI, the terminal may perform DL signal reception and / or UL signal transmission scheduled via DCI. Here, the terminal may not perform operations other than DL signal reception and / or UL signal transmission scheduled via DCI (e.g., UL transmission without permission or configuration).

[0243] Method 3-4: Is a predefined or configured signal detected?

[0244] Method 3-4 will now be described in detail. When indicating or determining that the base station is performing a frame-based channel access process via the above-mentioned embodiment, information such as the FFP, COT, etc. of the base station may be indicated to the terminal or the terminal may receive information such as the FFP, COT, etc. of the base station. The terminal may determine the channel access of the base station by detecting or receiving a signal periodically transmitted from a specific symbol or time slot in the FFP of the base station. For example, when a predefined or configured synchronization signal block in the FFP of the base station is detected or received, the terminal may determine that the base station has accessed the channel in the FFP. When the terminal does not detect or receive the synchronization signal block, the terminal may determine that the base station has not accessed the channel in the FFP. Here, determining the channel access of the base station by using the synchronization signal block is only an example and the embodiment is not limited thereto. For example, the terminal may determine the channel access of the base station by detecting or receiving a CSI-RS, another RS ​​(e.g., a phase tracking RS), or a preamble code predefined or configured in the FFP of the base station.

[0245] When the terminal determines via method 3-4 that the base station cannot perform unlicensed band channel access in the FFP, the terminal does not perform scheduled or configured UL signal transmission in the FFP. When the terminal determines via method 3-4 that the base station has accessed an unlicensed band channel in the FFP, the terminal may perform scheduled or configured UL signal transmission in the FFP. Here, even when the terminal determines via method 3-4 that the base station has not accessed an unlicensed band channel in the FFP, when the symbol or time slot used to receive DL or UL scheduled DCI from the base station in the FFP is in the same FFP as the DL signal reception and / or UL signal transmission scheduled via DCI, the terminal may perform DL signal reception and / or UL signal transmission scheduled via DCI. Here, the terminal may not perform operations other than DL signal reception and / or UL signal transmission scheduled via DCI (e.g., UL transmission without permission or configuration).

[0246] [Fourth embodiment]

[0247] In an embodiment, a method regarding a base station and a terminal operating in an unlicensed frequency band will be described, by which the terminal determines whether UL signal transmission can be initiated in the FFP of the base station when the channel access procedure of the base station is a frame-based channel access procedure.

[0248] Will refer to Figure 6This is described in detail. A base station that performs a frame-based channel access process may perform a channel access process 690 immediately before FFP650, and determine whether the unlicensed band is in an idle state via the performed channel access process 690. When it is determined that the unlicensed band is in an idle state, the base station may send a DL signal or receive a UL signal from the terminal by accessing the unlicensed band during COT 660. Here, the base station may send a DL signal or receive a UL signal from the terminal only during a portion of the time (or symbol or time slot) 663 of COT 660, and may receive a UL signal from the terminal during RCOT 666 without sending a DL signal. Here, the transmission of the UL signal of the terminal during RCOT 666 may be performed as follows.

[0249] Transmission method 1: UL signal transmission of a terminal, in which a UL signal is transmitted via a transmission method for transmitting a UL data channel without receiving a separate scheduling DCI from a base station (hereinafter, without granting PUSCH transmission)

[0250] Transmission method 2: UL signal transmission of the terminal, in which the UL signal is transmitted during the COT 663 via a method of transmitting a UL data channel by receiving a scheduling DCI from a base station (hereinafter, granted PUSCH or scheduled PUSCH transmission based on the grant).

[0251] Here, both transmission method 1 and transmission method 2 may be UL signal transmission.

[0252] In other words, when the base station is to send a DL signal or receive a UL signal from the terminal only during a portion of the time (or symbol or time slot) 663 of COT 660, and receives a UL signal from the terminal without a separate DL signal transmission during RCOT 666, the terminal can operate as follows during RCOT 666.

[0253] Terminal 1: A terminal that transmits a UL signal via a transmission method for transmitting a UL data channel without receiving a separate scheduling DCI from a base station (hereinafter, without granting PUSCH transmission)

[0254] Terminal 2: A terminal that transmits a UL signal during COT 663 among terminals that transmit a UL signal by receiving a scheduling DCI from a base station (hereinafter, based on a granted PUSCH or scheduled PUSCH transmission) and a terminal that transmits a UL signal

[0255] Here, both Terminal 1 and Terminal 2 can transmit UL signals.

[0256] At this time, the base station may transmit information about the RCOT 666 in which the DL signal is not transmitted among the COT 660 to the terminal via the following method.

[0257] Method 4-1: Sending RCOT information through SFI sent via PDCCH

[0258] Method 4-1 will now be described in detail. The base station may send information about the COT of the base station in the FFP to the terminal by using the slot format information of the slot in which the COT is configured. Here, the slot format information of the slot may be sent to the terminal via the SFI sent via the PDCCH. At this time, the terminal receiving the SFI may determine that the slot indicated as a flexible slot in the SFI about the received slot is the RCOT. Here, the terminal may determine that the slots and symbols that are continuously indicated as not flexible in reverse chronological order (or reverse slot index order) from the last slot in which the slot format was indicated via the SFI during COT660 are not RCOT.

[0259] refer to Figure 6 , the base station may transmit information about the COT 660 of the base station in the FFP 650 to the terminal via the slot format information 610 to 614 of the slots constituting the COT 660. The terminal may receive the slot format information, and determine the COT 663 and the RCOT 666 according to the received slot format information. In other words, the terminal may identify the slot format information from the last slot 604 in the slots indicated via the slot format information in reverse time order or reverse slot index order (604→603→602→601→600), and determine the continuous slots and symbols indicated as flexible (e.g., from the last symbol of the slot n+4 to the seventh symbol of the slot n+3) as the RCOT. In the RCOT 666, the terminal that transmits the UL signal via a transmission method for transmitting a UL data channel without separately receiving a scheduling DCI from the base station (hereinafter, without granting PUSCH transmission) may transmit the UL signal. Here, a terminal that sends a UL signal in COT 663 by a method of sending a UL data channel by receiving a scheduling DCI from a base station (hereinafter, a licensed PUSCH-based or scheduled PUSCH transmission), a terminal that sends a UL signal in COT 663 can send a UL signal in RCOT 666, or both the terminal without a licensed PUSCH and the terminal based on a licensed PUSCH transmission can send a UL signal.

[0260] In the above, a method has been described in which a base station indicates RCOT as a flexible symbol and a terminal determines RCOT when receiving the flexible symbol, but the base station is able to indicate RCOT as a UL symbol, and the terminal is able to identify the slot format information from the last slot in the slot indicated by the slot format information in reverse time order or reverse slot index order, and determine the consecutive slots and symbols indicated as UL symbols as RCOT.

[0261] Method 4-2: Sending RCOT information via DCI

[0262] Another method of transmitting information about RCOT 666 to the terminal through its base station is as follows. The base station may transmit the RCOT information to the terminal by adding the RCOT information to a field of the DCI in which the SFI is transmitted or via a field of the DCI other than the DCI in which the SFI is transmitted. Here, the RCOT information may include time slot and symbol information and may be represented as in Table 6.

[0263] When a terminal that transmits a UL signal in COT 663 transmits a UL signal in RCOT 666 by a method of transmitting a UL data channel by receiving a scheduling DCI from a base station (hereinafter, based on a granted PUSCH or scheduled PUSCH transmission), the terminal can perform UL signal transmission in RCOT 666 by using the previously received scheduling DCI. For example, frequency resource region allocation information, time resource region allocation information, transport block size (TBS), MCS, etc. of the scheduling DCI are maintained, and the HARQ process ID indicated by the DCI can be increased one by one to perform UL signal transmission.

[0264] refer to Figure 6 , during RCOT 666, when a terminal that has performed a PUSCH transmission indicated by a HARQ process ID p via a scheduling DCI in time slot n+2 602 performs a PUSCH transmission in time slot n+4 604, the terminal may perform the PUSCH transmission by assuming that the PUSCH transmission in time slot N+4 604 is p+1 increased by one from the HARQ process ID p indicated by the UL scheduling information most recently received before the PUSCH transmission or the scheduling information about the PUSCH most recently sent before the PUSCH transmission.

[0265] Figure 7 is a flow chart of the operation of a base station according to an embodiment.

[0266] refer to Figure 7 At operation 700, the base station may determine whether to use a frame-based channel access procedure or a service-based channel access procedure, and send the determined channel access procedure to the terminal via at least one of PBCH, SIB, and RRC signaling. At operation 710, when the frame-based channel access procedure is used, the base station may configure at least one of FFP, offset, and COT in FFP, and send the configured information to the terminal via at least one of SIB and RRC signaling.

[0267] In operation 720, the base station performs a channel access procedure immediately before the configured FFP.

[0268] When it is determined in operation 730 that the unlicensed band is in an idle state as a result of the channel access process, the base station may perform DL signal transmission and DL signal reception during the COT of the FFP in operation 750. Here, the base station may transmit time slot format information about the time slot in which the COT is configured to the terminal. In addition, the base station may transmit time slot format information about the time (symbol or time slot) not used for DL ​​signal transmission in the COT.

[0269] When it is determined in operation 730 that the unlicensed frequency band is not in an idle state as a result of the channel access procedure, the base station may return to operation 720 and perform the channel access procedure immediately before the configured FFP.

[0270] Figure 8 is a flowchart of the operation of the terminal according to the embodiment.

[0271] refer to Figure 8 At operation 800, the terminal may receive whether a frame-based channel access procedure or a service-based channel access procedure is used as the channel access procedure of the base station via at least one of PBCH, SIB, and RRC signaling. When the base station uses the frame-based channel access procedure, at operation 810, the terminal may receive at least one of FFP, offset, and COT in FFP via at least one of SIB and RRC signaling.

[0272] At operation 820, the terminal may search for a PDCCH according to a PDCCH search period and resources configured in the FFP, and at operation 830, check channel access of a base station according to the above-described embodiment.

[0273] When it is determined in operation 830 that the base station does not access the unlicensed band, the terminal does not perform UL transmission configured via the scheduled UL signal and / or the higher layer signal regardless of the scheduling in operation 820. In this case, the terminal returns to operation 820 and searches for the PDCCH according to the PDCCH search period and resources configured in the FFP.

[0274] When it is determined in operation 830 that the base station has accessed the unlicensed band, in operation 840, the terminal may perform UL signal transmission or DL ​​signal reception configured via a scheduled UL signal and / or a higher layer signal.

[0275] Fig. 9 is a block diagram of an internal configuration of a base station according to an embodiment.

[0276] like Fig. 9As shown, the base station according to the embodiment may include a transceiver 910, a memory 920 and a processor 930. The transceiver 910, the memory 920 and the processor 930 of the base station may operate according to the communication method of the above-mentioned base station. However, the components of the base station are not limited thereto. For example, the base station may include more or less components than the above-mentioned components. In addition, the processor 930, the transceiver 910 and the memory 920 may be implemented as a single chip. In addition, the processor 930 may include at least one processor.

[0277] The transceiver 910 collectively refers to a base station receiver and a base station transmitter, and can send / receive signals to / from a terminal. The signals sent to or received from the terminal may include control information and data. The transceiver 910 may include: an RF transmitter for up-converting and amplifying the frequency of the transmitted signal; and an RF receiver for amplifying the low noise and down-converting the frequency of the received signal. However, this is only an example of the transceiver 910, and the components of the transceiver 910 are not limited to the RF transmitter and the RF receiver.

[0278] In addition, the transceiver 910 may receive a signal through a wireless channel and output it to the processor 930 , and may transmit a signal output from the processor 930 through a wireless channel.

[0279] The memory 920 may store programs and data required for the operation of the base station. In addition, the memory 920 may store control information or data included in a signal obtained by the base station. The memory 920 may be a storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0280] The processor 930 may control a series of processes so that the base station operates as described above. For example, the transceiver 910 may receive a data signal including a control signal transmitted by a terminal, and the processor 930 may determine a result of receiving the control signal and the data signal transmitted by the terminal.

[0281] Fig.10 is a block diagram showing the internal structure of a terminal according to an embodiment of the present disclosure. Fig.10 As shown, the terminal of the present disclosure may include a transceiver 1010, a memory 1020 and a processor 1030. The transceiver 1010, the memory 1020 and the processor 1030 of the terminal may operate according to the communication method of the above-mentioned terminal. However, the components of the terminal are not limited thereto. For example, the terminal may include more or less components than the above-mentioned components. In addition, the processor 1030, the transceiver 1010 and the memory 1020 may be implemented as a single chip. In addition, the processor 1030 may include at least one processor.

[0282] The transceiver 1010 collectively refers to a terminal receiver and a terminal transmitter, and can send signals to / receive signals from a base station. The signals sent to or received from the base station may include control information and data. In this regard, the transceiver 1010 may include: an RF transmitter for up-converting and amplifying the frequency of the transmitted signal; and an RF receiver for amplifying the low noise and down-converting the frequency of the received signal. However, this is only an example of the transceiver 1010, and the components of the transceiver 1010 are not limited to the RF transmitter and the RF receiver.

[0283] In addition, the transceiver 1010 may receive a signal through a wireless channel and output it to the processor 1030 , and may transmit a signal output from the processor 1030 through a wireless channel.

[0284] The memory 1020 may store programs and data required for the operation of the terminal. In addition, the memory 1020 may store control information or data included in the signal obtained by the terminal. The memory 1020 may be a storage medium such as ROM, RAM, hard disk, CD-ROM and DVD, or a combination of storage media.

[0285] The processor 1030 may control a series of processes so that the terminal operates as described above. For example, the transceiver 1010 may receive a data signal including a control signal, and the processor 1030 may determine a result of receiving the data signal.

[0286] The methods according to the embodiments described in the claims or detailed description of the present disclosure may be implemented in hardware, software, or a combination of hardware and software.

[0287] When the electronic structure and method are implemented in software, a computer-readable recording medium having one or more programs (software modules) recorded thereon may be provided. One or more programs recorded on the computer-readable recording medium are configured to be executable by one or more processors in the electronic device. One or more programs include instructions for executing the method according to the embodiments described in the claims or detailed description of the present disclosure.

[0288] The program (e.g., software module or software) may be stored in a random access memory (RAM), non-volatile memory including flash memory, a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic disk storage device, a compact disk-ROM (CD-ROM), a digital versatile disk (DVD), another type of optical storage device, or a cassette tape. Alternatively, the program may be stored in a memory system that includes a combination of some or all of the above storage devices. In addition, each memory device may include multiple.

[0289] The program may also be stored in an attachable storage device accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wireless LAN (WLAN), or a storage area network (SAN), or a combination thereof. The storage device may be connected to an apparatus according to an embodiment of the present disclosure via an external port. Additional storage devices on the communication network may also be connected to an apparatus performing an embodiment of the present disclosure.

[0290] In the foregoing embodiments of the present disclosure, the elements included in the present disclosure are represented in singular or plural form according to the embodiment. However, the singular or plural form is appropriately selected for the convenience of explanation, and the present disclosure is not limited thereto. In this way, the elements represented in plural form may also be configured as a single element, and the elements represented in singular form may also be configured as multiple elements.

[0291] At the same time, the embodiments of the present disclosure described with reference to this specification and the accompanying drawings are only illustrations of specific examples to easily facilitate the description and understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those of ordinary skill in the art that other modifications based on the technical ideas of the present disclosure are feasible. In addition, the embodiments can be combined with each other as needed. For example, the base station and the terminal can operate using some of the methods proposed in the present disclosure combined together. In addition, embodiments are proposed based on 5G or NR systems, but other modifications based on the technical ideas of the embodiments can be implemented on other systems such as LTE, LTE-A, and LTE-A-Pro systems.

Claims

1. A method for performing a channel access procedure at a terminal in an unlicensed frequency band, the method comprising: receiving information indicating a type of channel access procedure in an unlicensed frequency band from a base station; receiving a frame-based channel access procedure configuration including a fixed frame period FFP from a base station; In the case where the type of the channel access procedure is a frame-based channel access procedure, based on the FFP, determining a channel occupation time COT and a start time of the channel occupation, wherein the start time of the channel occupation is determined based on the time period and the FFP; as well as Based on the downlink signal from the base station within the COT, an uplink signal is transmitted to the base station.

2. The method according to claim 1, wherein: The downlink signal includes at least one of a Demodulation Reference Signal (DMRS), a Physical Downlink Control Channel (PDCCH), and a preset signal.

3. The method according to claim 1, wherein: The maximum COT is determined by the following equation 2, Equation 2: COT = FFP x Z / 100, where Z = 95.

4. The method according to claim 1, further comprising: receiving, from the base station, remaining channel occupancy time RCOT information for the base station not to send a downlink signal during the COT period, The sending of the uplink signal to the base station includes: based on the RCOT information, sending the uplink signal in the absence of uplink scheduling from the base station.

5. The method according to claim 1, wherein: Information indicating that a type of a channel access procedure in an unlicensed band is a frame-based channel access procedure is received from a base station via at least one of: a system information block (SIB) and a radio signaling control (RRC) signaling.

6. The method according to claim 1, wherein: When the base station is not occupying a channel within the COT, no uplink signal is transmitted.

7. A method for a base station in an unlicensed frequency band to perform a channel access procedure, the method comprising: determining a type of channel access procedure in an unlicensed frequency band; sending information indicating a type of channel access procedure in an unlicensed frequency band to a terminal; Sending a frame-based channel access procedure configuration including a fixed frame period FFP to the terminal; In case the type of the channel access procedure is a frame-based channel access procedure, determining a channel occupation time COT in the FFP; as well as receiving an uplink signal from the terminal based on the downlink signal to the terminal within the COT, The start time of channel occupation is determined based on the time period and FFP.

8. A terminal for performing a channel access procedure in an unlicensed frequency band, the terminal comprising: Transceiver; at least one memory storing a program and data for performing a channel access procedure in an unlicensed frequency band; as well as At least one processor, by running a program stored in at least one memory, is configured to: receiving, from a base station via a system information block (SIB), information indicating a type of a channel access procedure in an unlicensed band; receiving, from a base station, a frame-based channel access procedure configuration including a fixed frame period FFP; In the case where the type of the channel access procedure is a frame-based channel access procedure, determining a channel occupation time COT and a start time of the channel occupation based on the FFP, wherein the start time of the channel occupation is determined based on the time period and the FFP; as well as Based on the downlink signal from the base station within the COT, an uplink signal is transmitted to the base station.

9. The terminal according to claim 8, wherein: The downlink signal includes at least one of a Demodulation Reference Signal (DMRS), a Physical Downlink Control Channel (PDCCH), and a preset signal.

10. The terminal according to claim 8, wherein: The maximum COT is determined by the following equation 2, Equation 2: COT = FFP x Z / 100, where Z = 95.

11. The terminal according to claim 9, wherein: The at least one processor is further configured to: receiving, from the base station, remaining channel occupancy time RCOT information for the base station not to send a downlink signal during the COT period; as well as Based on the RCOT information, an uplink signal is transmitted without scheduling about the uplink from the base station.

12. The terminal according to claim 9, wherein: Information indicating that a type of a channel access procedure in an unlicensed band is a frame-based channel access procedure is received from a base station via at least one of: a system information block (SIB) and a radio resource control (RRC) signaling.

13. The terminal according to claim 9, wherein: The at least one processor is further configured to: When the base station is not occupying a channel within the COT, no uplink signal is transmitted.

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