Resource allocation method for performing transmission in unlicensed band and device using same

Abstract

The present invention relates to a resource allocation method for performing transmission in an unlicensed band and a device using the same, and provides a resource allocation method for uplink transmission on an unlicensed band in a wireless communication system, particularly a cellular wireless communication system, and a method, apparatus and system for transmitting scheduling information at a base station and performing transceiving at a terminal. Further, provided are a method for efficiently transmitting a signal in a wireless communication system, particularly in a cellular wireless communication system, and a device therefor, another object of the present invention is to provide: a method for efficiently sensing a channel and transmitting a signal / channel in a specific frequency band (e.g., an unlicensed band); the invention discloses a method for receiving corresponding signals / channels and equipment thereof.

Description

[0001] This application is a divisional application of a patent application with application number 202080032655.0 (PCT / KR2020 / 095055), which was submitted to the China Patent Office on October 29, 2021, with an international application date of March 30, 2020, and the invention name is “Resource allocation method for performing transmission in an unlicensed frequency band and device using the same”. Technical Field

[0002] The present disclosure relates to a method for allocating uplink resources when using an NR-based frame structure and system in an unlicensed band, a method for transmitting resource allocation information by a base station, and a method, device, and system for receiving and transmitting by a UE. Background Art

[0003] After the commercialization of the fourth generation (4G) communication system, in order to meet the increasing demand for wireless data services, efforts are being made to develop a new fifth generation (5G) communication system. The 5G communication system is referred to as an ultra-4G network communication system, a post-LTE system, or a new radio (NR) system. In order to achieve high data transmission rates, the 5G communication system includes a system operating in a millimeter wave (mmWave) band of 6 GHz or higher, and includes a communication system operating in a band of 6 GHz or lower in terms of ensuring coverage, so that the implementation in the base station and the terminal is under consideration.

[0004] The 3rd Generation Partnership Project (3GPP) NR system improves the spectrum efficiency of the network and enables communication providers to provide more data and voice services over a given bandwidth. Therefore, the 3GPP NR system is designed to meet the demand for high-speed data and media transmission in addition to supporting a large amount of voice. The advantages of the NR system are higher throughput and lower latency on the same platform, support for frequency division duplex (FDD) and time division duplex (TDD), and low operating costs due to an enhanced end-user environment and simple architecture.

[0005] For more efficient data processing, the dynamic TDD of the NR system can use a method for changing the number of orthogonal frequency division multiplexing (OFDM) symbols that can be used in the uplink and downlink according to the data service direction of the cell user. For example, when the downlink service of the cell is greater than the uplink service, the base station can allocate multiple downlink OFDM symbols to the time slot (or subframe). Information about the time slot configuration should be sent to the terminal.

[0006] In order to reduce the path loss of radio waves and increase the transmission distance of radio waves in the mmWave band, in the 5G communication system, beamforming, massive multiple input / output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, hybrid beamforming combining analog beamforming and digital beamforming, and massive antenna technology are discussed. In addition, for the network improvement of the system, in the 5G communication system, technology development related to evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), vehicle-to-everything communication (V2X), wireless backhaul, non-terrestrial network communication (NTN), mobile networks, cooperative communication, coordinated multipoint (CoMP), interference cancellation, etc. is being carried out. In addition, in the 5G system, hybrid FSK and QAM modulation (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 connection technologies are being developed.

[0007] Meanwhile, in a human-centered connection network where humans generate and consume information, the Internet has evolved into an Internet of Things (IoT) network that exchanges information between distributed components such as objects. Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology through connection with a cloud server, is also emerging. In order to realize IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology and security technology are required, so that in recent years, technologies such as sensor networks, machine-to-machine (M2M) and machine type communication (MTC) have been studied to connect between objects. In the IoT environment, it is possible to provide intelligent Internet technology (IT) services that collect and analyze data generated from connected objects to create new value in human life. Through the integration and mixing of existing information technology (IT) and various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart home appliances and advanced medical services.

[0008] Therefore, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine type communications (MTC) are implemented through technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN, which is the above-mentioned big data processing technology, is an example of the fusion of 5G technology and IoT technology. In general, mobile communication systems are developed to provide voice services while ensuring the activities of users.

[0009] However, mobile communication systems are gradually expanding not only voice services but also data services, and have now developed to the extent of providing high-speed data services. However, in the mobile communication systems currently providing services, due to resource shortages and users' high-speed service requirements, more advanced mobile communication systems are needed.

[0010] In recent years, with the surge in mobile traffic due to the popularity of smart devices, it has become increasingly difficult to cope with the increase in data usage for providing cellular communication services using only existing licensed spectrum or licensed frequency bands.

[0011] Under such circumstances, a method of providing a cellular communication service using an unlicensed spectrum or an unlicensed frequency band (eg, a 2.4 GHz band, a 5 GHz band, or a higher frequency band, etc.) is being discussed in order to solve the problem of lack of spectrum.

[0012] Unlike in licensed bands where telecommunications operators secure exclusive use rights through auctions and other procedures, in unlicensed bands, multiple communication devices can be used simultaneously without restriction, provided that only a certain level of adjacent band protection regulations are followed. For this reason, when unlicensed bands are used for cellular communication services, it is difficult to ensure communication quality to the level provided in licensed bands, and interference with existing wireless communication devices (e.g., wireless LAN devices) using the unlicensed bands is likely to occur.

[0013] In order to use LTE and NR technologies in unlicensed bands, research on coexistence with existing devices for unlicensed bands and effective sharing of wireless channels with other wireless communication devices will be conducted in advance. That is, a robust coexistence mechanism (RCM) needs to be developed so that devices using LTE and NR technologies in unlicensed bands do not affect existing devices for unlicensed bands. Summary of the invention

[0014] Technical issues

[0015] The object of the present invention is to provide an uplink channel access method for performing broadband operation on an unlicensed frequency band in a wireless communication system (particularly a cellular wireless communication system), and a method, device and system for sending and receiving by a UE. Another object of the present invention is to provide a method for effectively sending signals in a wireless communication system (particularly a cellular wireless communication system) and a device thereof. Yet another object of the present invention is to provide a method for effectively sensing a channel in a specific frequency band (e.g., an unlicensed frequency band) and sending a signal / channel, a method for receiving a corresponding signal / channel and a device thereof.

[0016] The technical problems to be solved by the present disclosure may not be limited to the above-mentioned technical problems, and those skilled in the art will clearly understand other technical problems not mentioned through the following description.

[0017] Technical Solution

[0018] A UE in a wireless communication system according to an embodiment of the present disclosure includes: a communication module; and a processor, the processor being configured to control the communication module. The processor is configured to: receive downlink control information (DCI) for allocating at least one subband and a plurality of resource blocks from a base station, the at least one subband and the plurality of resource blocks being used to transmit a PUSCH (physical uplink shared channel); and transmit the PUSCH to the base station through the plurality of resource blocks received via the DCI, wherein the DCI includes first resource allocation information related to the position of the at least one subband and second resource allocation information related to the position of the plurality of resource blocks, based on the first resource allocation information, the at least one subband is included in an activated bandwidth part (BWP), and based on the second resource allocation information, the plurality of resource blocks have an interleaved structure, wherein the resource blocks are continuously allocated to the activated BWP at regular intervals.

[0019] In the present disclosure, based on the first resource allocation information, the at least one subband is continuously allocated in the activated BWP.

[0020] In the present disclosure, the first resource allocation information related to the location of the at least one subband is included in the DCI through a RIV (Resource Indication Value) scheme.

[0021] In the present disclosure, the second resource allocation information related to the locations of the plurality of resource blocks is included in the DCI through a bitmap scheme or a RIV (Resource Indication Value) scheme according to a subcarrier spacing.

[0022] In the present disclosure, when the subcarrier spacing is 30kHz, the second resource allocation information related to the positions of the multiple resource blocks is included in the DCI through the bitmap scheme, and based on the bitmap scheme, the positions of the multiple resource blocks are indicated by each bit value included in the second resource allocation information.

[0023] In the present disclosure, when the subcarrier spacing is 15kHz, the second resource allocation information related to the positions of the multiple resource blocks is included in the DCI through the RIV scheme, and the second resource allocation information includes the starting index of the multiple resource blocks and the number of the multiple resource blocks based on the RIV scheme.

[0024] In the present disclosure, the first resource allocation information includes a starting position and a number of the at least one subband.

[0025] In the present disclosure, the first resource allocation information and the second resource allocation information are encoded together and included in the DCI.

[0026] In the present disclosure, the indication information that the first resource allocation information and the second resource allocation information are encoded together is calculated sequentially in ascending order by giving priority to one of the number of the at least one subband or the start index of the plurality of resource blocks.

[0027] In the present disclosure, the plurality of resource blocks have an interleaved structure on the at least one subband in which an LBT (Listen Before Talk) operation for channel access in an unlicensed band is performed.

[0028] The present disclosure provides a method, comprising: receiving downlink control information (DCI) for allocating at least one subband and multiple resource blocks from a base station, the at least one subband and the multiple resource blocks being used to send a PUSCH (physical uplink shared channel); and sending the PUSCH to the base station through the multiple resource blocks received via the DCI, wherein the DCI includes first resource allocation information related to the position of the at least one subband and second resource allocation information related to the positions of the multiple resource blocks, based on the first resource allocation information, the at least one subband is included in an activated bandwidth part (BWP), and based on the second resource allocation information, the multiple resource blocks have an interleaved structure, wherein the resource blocks are continuously allocated to the activated BWP at regular intervals.

[0029] The present disclosure provides a base station, comprising: a communication module; and a processor, the processor being configured to control the communication module, wherein the processor is configured to send downlink control information (DCI) for allocating at least one subband and multiple resource blocks to a UE, the at least one subband and the multiple resource blocks being used to send a PUSCH (physical uplink shared channel); and receive the PUSCH sent from the terminal through the multiple resource blocks sent via the DCI, the DCI comprising first resource allocation information related to the position of the at least one subband and second resource allocation information related to the positions of the multiple resource blocks, based on the first resource allocation information, the at least one subband is included in an activated bandwidth part (BWP), and based on the second resource allocation information, the multiple resource blocks have an interleaved structure, wherein the resource blocks are continuously allocated to the activated BWP at regular intervals.

[0030] Effects of the Invention

[0031] According to various embodiments of the present disclosure, a method and apparatus for receiving and transmitting when resource allocation for uplink transmission is performed in a wireless communication system (particularly a cellular wireless communication system) is provided. In addition, a method and apparatus for accessing a channel in a specific frequency band (e.g., an unlicensed frequency band) and effectively transmitting a signal are provided.

[0032] Effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above can be clearly understood by a person of ordinary skill in the art from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 An example of a radio frame structure used in a wireless communication system is illustrated.

[0034] Figure 2 An example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system is illustrated.

[0035] Figure 3 A diagram for explaining physical channels used in a 3GPP system and a typical signal transmission method using the physical channels.

[0036] Figure 4 Illustration of SS / PBCH blocks used for initial cell access in a 3GPP NR system.

[0037] Figure 5 Illustration of a process for transmitting control information and a control channel in a 3GPP NR system.

[0038] Figure 6 Illustration of a control resource set (CORESET) in which a physical downlink control channel (PUCCH) can be transmitted in a 3GPP NR system.

[0039] Figure 7 A method for configuring a PDCCH search space in a 3GPP NR system is illustrated.

[0040] Figure 8 is a conceptual diagram illustrating carrier aggregation.

[0041] Fig. 9 It is a diagram for explaining signal carrier communication and multi-carrier communication.

[0042] Fig.10 is a diagram showing an example in which a cross-carrier scheduling technology is applied.

[0043] Fig.11 The diagram illustrates a code block group (CBG) configuration and its time-frequency resource mapping according to an embodiment of the present invention.

[0044] Fig.12 The diagram illustrates a process in which a base station performs TB-based transmission or CBG-based transmission according to an embodiment of the present invention, and a UE sends HARQ-ACK in response thereto.

[0045] Fig.13 Figure 1 shows a New Radio Unlicensed (NR-U) service environment.

[0046] Fig.14 An embodiment of a deployment scenario of a UE and a base station in an NR-U service environment is illustrated.

[0047] Fig.15 A communication method (eg, wireless LAN) operating in an existing unlicensed frequency band is illustrated.

[0048] Fig.16 The diagram illustrates a channel access process based on Category 4 LBT according to an embodiment of the present invention.

[0049] Fig.17 An embodiment of a method of adjusting a contention window size (CWS) based on HARQ-ACK feedback is illustrated.

[0050] Fig.18 is a block diagram illustrating the configuration of a UE and a base station according to an embodiment of the present invention.

[0051] Fig.19 is a flowchart illustrating an example of a method of transmitting uplink data in an unlicensed band according to an embodiment of the present invention.

[0052] Fig. 20 An example of a structure of resources for transmitting a PUSCH (Physical Uplink Shared Channel) according to an embodiment of the present invention is illustrated.

[0053] Fig.21 A diagram illustrating an example of an interlace structure for allocating uplink resources in LTE-LAA.

[0054] Fig. 22 An example of candidate LBT subbands and their interleaving structure for uplink PUSCH transmission in an activated bandwidth part (BWP) with multiple LBT subbands among one or more BWPs is illustrated.

[0055] Fig.23 is a flowchart illustrating an example of a method in which a UE receives resources of an unlicensed band from a base station and transmits uplink data according to another embodiment of the present disclosure.

[0056] Fig.24 is a flowchart illustrating an example of a method in which a base station allocates resources of an unlicensed band to a UE and receives uplink data according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0057] The terms used in the specification adopt the currently widely used general terms as much as possible by considering the functions in the present invention, but these terms may be changed according to the intentions, habits and emergence of new technologies of the technicians in the field. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, their meanings will be described in the corresponding description part of the present invention. Therefore, it is intended to disclose that the terms used in the specification should not be analyzed based only on the names of the terms, but should be analyzed based on the substantial meanings of the terms and contents in the entire specification.

[0058] Throughout the specification and the claims that follow, when it is described that an element is "connected" to another element, the element may be "directly connected" to the other element or "electrically connected" to the other element through a third element. In addition, unless explicitly described to the contrary, the word "comprising" will be understood to imply the inclusion of the elements without implying the exclusion of any other elements. Furthermore, in some exemplary embodiments, limitations such as "greater than or equal to" or "less than or equal to" based on a specific threshold value may be appropriately replaced with "greater than" or "less than", respectively.

[0059] The following technologies can be used in various wireless access systems: such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier-FDMA (SC-FDMA), etc. CDMA can be implemented by wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented by wireless technologies such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented by wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), etc. UTRA is part of Universal Mobile Telecommunications System (UMTS). The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using Evolved UMTS Terrestrial Radio Access (E-UTRA), and LTE Advanced (A) is an evolved version of 3GPP LTE. 3GPP New Radio (NR) is a system designed separately from LTE / LTE-A, and is a system for supporting enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine type communication (mMTC) services as requirements of IMT-2020. For the sake of clear description, 3GPP NR is mainly described, but the technical idea of ​​the present invention is not limited thereto.

[0060] Unless otherwise specified herein, the base station may include a next generation node B (gNB) defined in 3GPP NR. In addition, unless otherwise specified, the terminal may include a user equipment (UE). In the following, in order to help understand the description, each embodiment describes each content separately, but each embodiment may be used in combination with each other. In this specification, the configuration of the UE may indicate the configuration by the base station. In more detail, the base station may configure the value of a parameter used in the operation of the UE or the wireless communication system by sending a channel or a signal to the UE.

[0061] Figure 1 An example of a radio frame structure used in a wireless communication system is illustrated.

[0062] refer to Figure 1 , the radio frame (or radio frame) used in the 3GPP NR system may have a 10ms (Δf max N f / 100)*T c ) length. In addition, the wireless frame includes 10 subframes (SF) of equal size. Here, Δf max =480*10 3 Hz,N f =4096,T c =1 / (Δf ref *N f,ref ), Δf ref =15*10 3 Hz, and N f,ref =2048. Numbers from 0 to 9 can be assigned to 10 subframes in one radio frame respectively. Each subframe has a length of 1 ms and can include one or more time slots according to the subcarrier spacing. More specifically, in the 3GPP NR system, the subcarrier spacing that can be used is 15*2 μ kHz, and μ can have a value of μ=0 to 4 as a subcarrier spacing configuration. That is, 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz can be used for subcarrier spacing. One subframe with a length of 1ms may include 2 μ In this case, the length of each time slot is 2 -μ ms. It can be from 0 to 2 μ -1 are assigned to the 2 μ In addition, the time slots from 0 to 10*2 μ Numbers of -1 are respectively allocated to time slots in a radio frame. Time resources may be distinguished by at least one of a radio frame number (also referred to as a radio frame index), a subframe number (also referred to as a subframe index), and a time slot number (or a time slot index).

[0063] Figure 2 An example of a downlink (DL) / uplink (UL) time slot structure in a wireless communication system is illustrated. In particular, Figure 2 The structure of the resource grid of the 3GPP NR system is shown.

[0064] There is one resource grid per antenna port. Figure 2 , a time slot includes multiple orthogonal frequency division multiplexing (OFDM) symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. An OFDM symbol also refers to a symbol interval. Unless otherwise specified, an OFDM symbol may be referred to as a symbol. An RB includes 12 consecutive subcarriers in the frequency domain. Reference Figure 2 , the signal transmitted from each time slot can be composed of N size,μ grid,x *N RB sc subcarriers and N slot symb Here, when the signal is a DL signal, x=DL, and when the signal is a UL signal, x=UL. N size,μ grid,x represents the number of resource blocks (RBs) according to the subcarrier spacing component μ (x is DL or UL), and N slot symb N represents the number of OFDM symbols in a time slot. RB sc is the number of subcarriers constituting one RB and N RB sc = 12. The OFDM symbol may be called a cyclic shift OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol according to a multiple access scheme.

[0065] The number of OFDM symbols included in one slot may vary depending on the length of the cyclic prefix (CP). For example, in the case of a normal CP, one slot includes 14 OFDM symbols, but in the case of an extended CP, one slot may include 12 OFDM symbols. In a specific embodiment, the extended CP may be used only at a 60kHz subcarrier spacing. Figure 2 In the embodiment, for the convenience of description, one time slot is configured with 14 OFDM symbols as an example, but the embodiments of the present disclosure can be applied to time slots with different numbers of OFDM symbols in a similar manner. Figure 2 , each OFDM symbol includes N size,μ grid,x *N RB scsubcarriers. The types of subcarriers can be divided into data subcarriers for data transmission, reference signal subcarriers for transmission of reference signals, and guard bands. The carrier frequency is also called the center frequency (fc).

[0066] An RB can be composed of N RB sc For reference, a resource configured with one OFDM symbol and one subcarrier may be referred to as a resource element (RE) or tone. Thus, one RB can be configured with N slot symb *N RB sc resource elements. Each resource element in the resource grid can be uniquely defined by a pair of indices (k, l) in a time slot. k can be a random number from 0 to N in the frequency domain. size,μ grid,x *N RB sc –1 is the assigned index, and l can be from 0 to N in the time domain slot symb –1 The assigned index.

[0067] In order for a UE to receive or send signals from or to a base station, the UE's time / frequency may be synchronized with that of the base station. This is because when the base station and the UE are synchronized, the UE is able to determine the time and frequency parameters necessary to demodulate the DL signal and send the UL signal at the correct time.

[0068] Each symbol of a radio frame used in a time division duplex (TDD) or unpaired spectrum may be configured with at least one of a DL symbol, a UL symbol, and a flexible symbol. A radio frame used as a DL carrier in a frequency division duplex (FDD) or paired spectrum may be configured with a DL symbol or a flexible symbol, and a radio frame used as a UL carrier may be configured with a UL symbol or a flexible symbol. In a DL symbol, DL transmission is possible, but UL transmission is unavailable. In a UL symbol, UL transmission is possible, but DL transmission is unavailable. A flexible symbol may be determined to be used as DL or UL according to a signal.

[0069] Information on the type of each symbol, i.e., information indicating any one of a DL symbol, a UL symbol, and a flexible symbol, may be configured by a cell-specific or common Radio Resource Control (RRC) signal. Additionally, information on the type of each symbol may be additionally configured by a UE-specific or dedicated RRC signal. The base station notifies, by using a cell-specific RRC signal, i) the period of a cell-specific slot configuration, ii) the number of slots having only DL symbols from the beginning of the period of the cell-specific slot configuration, iii) the number of DL symbols starting from the first symbol of the slot immediately following the slot having only DL symbols, iv) the number of slots having only UL symbols from the end of the period of the cell-specific slot configuration, and v) the number of UL symbols starting from the last symbol of the slot immediately preceding the slot having only UL symbols. Here, a symbol not configured with any one of a UL symbol and a DL symbol is a flexible symbol.

[0070] When the information on the symbol type is configured by a UE-specific RRC signal, the base station may signal, by a cell-specific RRC signal, whether the flexible symbol is a DL symbol or a UL symbol. In this case, the UE-specific RRC signal cannot change a DL symbol or a UL symbol configured by the cell-specific RRC signal into another symbol type. The UE-specific RRC signal may signal the number of DL symbols among the N slot symb symbols of the corresponding slot of each slot and the number of UL symbols among the N slot symb symbols of the corresponding slot. In this case, the DL symbols of a slot may be continuously configured from the first symbol to the i-th symbol of the slot. Additionally, the UL symbols of a slot may be continuously configured from the j-th symbol to the last symbol of the slot (where i < j). In a slot, a symbol not configured with any one of a UL symbol and a DL symbol is a flexible symbol.

[0071] The type of the symbol configured by the above RRC signal may be referred to as a semi-static DL / UL configuration. In a previously configured semi-static DL / UL configuration by an RRC signal, a flexible symbol may be indicated as a DL symbol, a UL symbol indication, or a flexible symbol by dynamic slot format information (SFI) transmitted on a Physical DL Control Channel (PDCCH). In this case, a DL symbol or a UL symbol configured by an RRC signal is not changed into another symbol type. Table 1 illustrates the dynamic SFI that the base station can indicate to the UE.

[0072] [Table 1]

[0073]

[0074] In Table 1, D represents a DL symbol, U represents a UL symbol, and X represents a flexible symbol. As shown in Table 1, a maximum of two DL / UL switchings may be allowed in one slot.

[0075] Figure 3 A diagram for explaining physical channels used in a 3GPP system (e.g., NR) and a typical signal transmission method using the physical channels.

[0076] If the power of the UE is turned on or the UE resides in a new cell, the UE performs an initial cell search (step S101). Specifically, the UE can synchronize with the BS in the initial cell search. To this end, the UE can receive a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as a cell ID. Thereafter, the UE can receive a physical broadcast channel from the base station and obtain broadcast information in the cell.

[0077] After the initial cell search is completed, the UE receives a physical downlink shared channel (PDSCH) based on the physical downlink control channel (PDCCH) and the information in the PDCCH, so that the UE can obtain more specific system information than the system information obtained through the initial cell search (S102). Here, the system information received by the UE is the cell common system information used for the normal operation of the UE in the physical layer in the radio resource control (RRC), and is called the remaining system information, or is called the system information block (SIB) 1.

[0078] When the UE initially accesses the base station or does not have radio resources for signal transmission (i.e., the UE is in RRC_idle mode), the UE can perform a random access procedure on the base station (step operations S103 to S106). First, the UE can send a preamble through a physical random access channel (PRACH) (step S103) and receive a response message for the preamble from the base station through a PDCCH and a corresponding PDSCH (step S104). When the UE receives a valid random access response message, the UE sends data including an identifier of the UE, etc. to the base station through a physical uplink shared channel (PUSCH) indicated by a UL grant sent from the base station through the PDCCH (step S105). Next, the UE waits for the reception of the PDCCH as an indication of the base station for conflict resolution. If the UE successfully receives the PDCCH through the UE's identifier (step S106), the random access procedure is terminated. The UE can obtain UE-specific system information for normal operation of the UE in the physical layer in the RRC layer during the random access procedure. When the UE obtains the UE-specific system information, the UE enters the RRC connection mode (RRC_connection mode).

[0079] The RRC layer is used to generate or manage messages for controlling the connection between the UE and the radio access network (RAN). In more detail, in the RRC layer, the base station and the UE can perform broadcasting cell system information required for each UE in the cell, management of mobility and switching, measurement reporting of the UE, storage management including UE capability management and device management. Generally, because the update period of the signal transmitted in the RRC layer is longer than the transmission time interval (TTI) in the physical layer, the RRC signal is not changed and maintained for a relatively long interval.

[0080] After the above procedure, the UE receives PDCCH / PDSCH (step S107) and sends a physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) (step S108) as a general UL / DL signal transmission procedure. In particular, the UE can receive downlink control information (DCI) through the PDCCH. The DCI may include control information such as resource allocation information for the UE. In addition, the format of the DCI may vary according to the intended use. The uplink control information (UCI) sent by the UE to the base station through the UL includes DL / UL ACK / NACK signals, channel quality indicators (CQI), precoding matrix indexes (PMI), rank indicators (RI), etc. Here, CQI, PMI and RI may be included in the channel state information (CSI). In the 3GPP NR system, the UE can send control information such as the above-mentioned HARQ-ACK and CSI through PUSCH and / or PUCCH.

[0081] Figure 4 Illustration of SS / PBCH blocks used for initial cell access in a 3GPP NR system.

[0082] When the power is turned on or when you want to access a new cell, the UE can obtain time and frequency synchronization with the cell and perform an initial cell search process. The UE can detect the physical cell identifier NcellID of the cell during the cell search process. To this end, the UE can receive synchronization signals from the base station, such as the primary synchronization signal (PSS) and the secondary synchronization signal (SSS), and synchronize with the base station. In this case, the UE is able to obtain information such as a cell identifier (ID).

[0083] refer to Figure 4 (a), the synchronization signal (SS) will be described in more detail. The synchronization signal can be classified into PSS and SSS. PSS can be used to obtain time domain synchronization and / or frequency domain synchronization, such as OFDM symbol synchronization and time slot synchronization. SSS can be used to obtain frame synchronization and cell group ID. Figure 4(a) and Table 2, the SS / PBCH block can be configured with 20 consecutive RBs (=240 subcarriers) on the frequency axis, and can be configured with 4 consecutive OFDM symbols on the time axis. In this case, in the SS / PBCH block, the PSS is sent in the first OFDM symbol and the SSS is sent in the third OFDM symbol through the 56th to 182nd subcarriers. Here, the lowest subcarrier index of the SS / PBCH block is numbered from 0. In the first OFDM symbol in which the PSS is sent, the base station does not send signals through the remaining subcarriers, i.e., the 0th to 55th subcarriers and the 183rd to 239th subcarriers. In addition, in the third OFDM symbol in which the SSS is sent, the base station does not send signals through the 48th to 55th subcarriers and the 183rd to 191st subcarriers. The base station sends the physical broadcast channel (PBCH) through the remaining REs in the SS / PBCH block except for the above signals.

[0084] [Table 2]

[0085]

[0086] The SS allows a total of 1008 unique physical layer cell IDs to be grouped into 336 physical layer cell identifier groups, each group including three unique identifiers, through a combination of three PSS and SSS, specifically so that each physical layer cell ID will be part of only one physical layer cell identifier group. cell ID =3N (1) ID +N (2) ID The physical layer cell identifier group can be indicated by an index N ranging from 0 to 335. (1) ID and an index N ranging from 0 to 2 indicating a physical layer identifier in the physical layer cell identifier group (2) ID The UE can detect the PSS and identify one of the three unique physical layer identifiers. In addition, the UE can detect the SSS and identify one of the 336 physical layer cell IDs associated with the physical layer identifier. In this case, the sequence d of the PSS PSS (n) are as follows.

[0087] d PSS (n) = 1-2x(m)

[0088]

[0089] 0≤n<127

[0090] Here, x(i+7)=(x(i+4)+x(i))mod2 and is given as

[0091] [x(6) x(5) x(4) x(3) x(2) x(1) x(0)]=[1 1 1 0 1 1 0].

[0092] In addition, the sequence d of SSS SSS (n) are as follows.

[0093] d SSS (n)=[1-2x0((n+m0)mod127)I1-2x1((n+m1)mod127)]

[0094]

[0095] 0≤n<127

[0096] here, and is given as

[0097] [x0(6) x0(5) x0(4) x0(3) x0(2) x0(1) x0(0)]=[0 0 0 0 0 0 1]

[0098] [x1(6) x1(5) x1(4) x1(3) x1(2) x1(1) x1(0)]=[0 0 0 0 0 0 1].

[0099] A radio frame having a length of 10 ms may be divided into two half frames having a length of 5 ms. Figure 4(b) The time slot in which the SS / PBCH block is sent in each half frame will be described. The time slot in which the SS / PBCH block is sent may be any one of cases A, B, C, D, and E. In case A, the subcarrier spacing is 15kHz and the starting time point of the SS / PBCH block is the ({2,8}+14*n)th symbol. In this case, at a carrier frequency of 3GHz or lower, n=0 or 1. In addition, at a carrier frequency higher than 3GHz and lower than 6GHz, it may be n=0, 1, 2, 3. In case B, the subcarrier spacing is 30kHz and the starting time point of the SS / PBCH block is {4,8,16,20}+28*n. In this case, at a carrier frequency of 3GHz or lower, n=0. In addition, at a carrier frequency higher than 3GHz and lower than 6GHz, it may be n=0, 1. In case C, the subcarrier spacing is 30kHz and the starting time point of the SS / PBCH block is the ({2,8}+14*n)th symbol. In this case, at a carrier frequency of 3 GHz or lower, n=0 or 1. In addition, at a carrier frequency higher than 3 GHz and lower than 6 GHz, it can be n=0, 1, 2, 3. In case D, the subcarrier spacing is 120 kHz and the starting time point of the SS / PBCH block is the ({4, 8, 16, 20} + 28*n)th symbol. In this case, at a carrier frequency of 6 GHz or higher, n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In case E, the subcarrier spacing is 240 kHz and the starting time point of the SS / PBCH block is the ({8, 12, 16, 20, 32, 36, 40, 44} + 56*n)th symbol. In this case, at a carrier frequency of 6 GHz or higher, n=0, 1, 2, 3, 5, 6, 7, 8.

[0100] Figure 5 This figure shows the process of sending control information and control channels in the 3GPP NR system. Figure 5(a), the base station may add a cyclic redundancy check (CRC) masked (e.g., XORed) with a radio network temporary identifier (RNTI) to control information (e.g., downlink control information (DCI)) (step S202). The base station may scramble the CRC with an RNTI value determined according to the purpose / target of each control information. The common RNTI used by one or more UEs can include at least one of a system information RNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI), and a transmit power control RNTI (TPC-RNTI). In addition, the UE-specific RNTI may include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, the base station may perform rate matching according to the amount of resources used for PDCCH transmission after performing channel coding (e.g., polarity coding) (step S204) (step S206). Thereafter, the base station may multiplex DCI based on a PDCCH structure based on a control channel element (CCE) (step S208). In addition, the base station may apply additional processes such as scrambling, modulation (e.g., QPSK), interleaving, etc. to the multiplexed DCI (step S210), and then map the DCI to the resource to be transmitted. CCE is a basic resource unit for PDCCH, and one CCE may include multiple (e.g., six) resource element groups (REGs). One REG may be configured with multiple (e.g., 12) REs. The number of CCEs used for one PDCCH may be defined as an aggregation level. In a 3GPP NR system, an aggregation level of 1, 2, 4, 8, or 16 may be used. Figure 5 (b) is a diagram related to multiplexing of a CCE aggregation level and a PDCCH, and illustrates the type of CCE aggregation level for one PDCCH and CCEs transmitted in the control region accordingly.

[0101] Figure 6 Illustration of a control resource set (CORESET) in which a physical downlink control channel (PUCCH) can be transmitted in a 3GPP NR system.

[0102] CORESET is a time-frequency resource in which PDCCH (i.e., a control signal for UE) is transmitted. In addition, the search space to be described later can be mapped to one CORESET. Therefore, the UE can monitor the time-frequency domain designated as the CORESET instead of monitoring all frequency bands for PDCCH reception, and decode the PDCCH mapped to the CORESET. The base station can configure one or more CORESETs for each cell to the UE. The CORESET can be configured with a maximum of three consecutive symbols on the time axis. In addition, the CORESET can be configured in units of six consecutive PRBs on the frequency axis. Figure 5 In the embodiment of FIG. 1 , CORESET#1 is configured with continuous PRBs, while CORESET#2 and CORESET#3 are configured with discontinuous PRBs. A CORESET can be located in any symbol in a time slot. For example, in Figure 5 In an embodiment of the present invention, CORESET#1 starts at the first symbol of the time slot, CORESET#2 starts at the fifth symbol of the time slot, and CORESET#9 starts at the ninth symbol of the time slot.

[0103] Figure 7 A method for setting a PUCCH search space in a 3GPP NR system is illustrated.

[0104] In order to send the PDCCH to the UE, each CORESET may have at least one search space. In an embodiment of the present disclosure, the search space is a set of all time-frequency resources (hereinafter referred to as PDCCH candidates) that can be used to send the PDCCH of the UE. The search space may include a common search space that requires UEs of 3GPP NR to search together and a terminal-specific search space or a UE-specific search space that requires a specific UE to search. In the common search space, the UE may monitor the PDCCH that is set so that all UEs in the cell belonging to the same base station search together. In addition, a UE-specific search space may be set for each UE so that the UE monitors the PDCCH assigned to each UE at a search space position that is different according to the UE. In the case of a UE-specific search space, since the limited control region to which the PDCCH can be allocated can be allocated, the search space between the UEs may partially overlap and be allocated. Monitoring the PDCCH includes blind decoding of the PDCCH candidates in the search space. When the blind decoding is successful, it can be expressed as (successfully) detecting / receiving the PDCCH, and when the blind decoding fails, it can be expressed as not detecting / not receiving or not successfully detecting / receiving the PDCCH.

[0105] For convenience of explanation, a PDCCH that is scrambled with a group common (GC) RNTI previously known to one or more UEs in order to send DL control information to one or more UEs is referred to as a group common (GC) PDCCH or a common PDCCH. In addition, a PDCCH that is scrambled with an RNTI of a specific terminal that is already known to a specific UE in order to send UL scheduling information or DL ​​scheduling information to a specific UE is referred to as a PDCCH of a specific UE. A common PDCCH may be included in a common search space, and a UE-specific PDCCH may be included in a common search space or a UE-specific PDCCH.

[0106] The base station may signal each UE or UE group through the PDCCH about information related to resource allocation of the paging channel (PCH) and the downlink shared channel (DL-SCH) as transmission channels (i.e., DL grant) or information related to resource allocation of the uplink shared channel (UL-SCH) and the hybrid automatic repeat request (HARQ) (i.e., UL grant). The base station may send the PCH transport block and the DL-SCH transport block through the PDSCH. The base station may send data excluding specific control information or specific service data through the PDSCH. In addition, the UE may receive data excluding specific control information or specific service data through the PDSCH.

[0107] The base station can include information in the PDCCH about which UE (one or more UEs) the PDSCH data is sent to and how the PDSCH data will be received and decoded by the corresponding UE, and send the PDCCH. For example, assume that the DCI sent on a specific PDCCH is CRC-masked with RNTI "A", and the DCI indicates that the PDSCH is allocated to radio resources "B" (e.g., frequency position) and indicates transmission format information "C" (e.g., transport block size, modulation scheme, coding information, etc.). The UE monitors the PDCCH using the RNTI information that the UE has. In this case, if there is a UE that performs blind decoding on the PDCCH using the "A" RNTI, the UE receives the PDCCH and receives the PDSCH indicated by "B" and "C" through the information of the received PDCCH.

[0108] Table 3 shows an embodiment of a physical uplink control channel (PUCCH) used in a wireless communication system.

[0109] [Table 3]

[0110] PUCCH format OFDM symbol length Number of bits 0 1-2 ≤2 1 4-14 ≤2 2 1-2 ＞2 3 4-14 ＞2 4 4-14 ＞2

[0111] PUCCH can be used to transmit the following UL control information (UCI).

[0112] - Scheduling Request (SR): information for requesting UL UL-SCH resources.

[0113] -HARQ-ACK: A response to the PDCCH (indicating a DL SPS release) and / or a response to a DL transport block (TB) on the PDSCH. HARQ-ACK indicates whether the information successfully sent on the PDCCH or PDSCH is received. The HARQ-ACK response includes a positive ACK (abbreviated as ACK), a negative ACK (hereinafter referred to as NACK), a discontinuous transmission (DTX), or NACK / DTX. Here, the term HARQ-ACK is used in a mixed manner with HARQ-ACK / NACK and ACK / NACK. Generally, ACK can be represented by a bit value of 1, while NACK can be represented by a bit value of 0.

[0114] - Channel State Information (CSI): Feedback information about the DL channel. The UE generates it based on the CSI-Reference Signal (RS) sent by the base station. Multiple Input Multiple Output (MIMO) related feedback information includes Rank Indicator (RI) and Precoding Matrix Indicator (PMI). The CSI can be divided into CSI Part 1 and CSI Part 2 according to the information indicated by the CSI.

[0115] In the 3GPP NR system, five PUCCH formats can be used to support various service scenarios, various channel environments, and frame structures.

[0116] PUCCH format 0 is a format capable of delivering 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 can be transmitted through one or two OFDM symbols on the time axis and one PRB on the frequency axis. When PUCCH format 0 is transmitted in two OFDM symbols, the same sequence on the two symbols can be transmitted through different RBs. In this case, the sequence can be a sequence that is cyclically shifted (CS) from the base sequence used in PUCCH format 0. As a result, the UE can obtain frequency diversity gain. In more detail, the UE can obtain frequency diversity gain based on M bit BitUCI(M bit =1 or 2) to determine the cyclic shift (CS) value m cs In addition, the CS value m can be calculated by cs The cyclic shift sequence is mapped to one OFDM symbol and 12 REs of one RB to transmit a basic sequence of length 12. When the number of cyclic shifts available to the UE is 12 and M bit =1, 1-bit UCI 0 and 1 can be mapped to two cyclic shift sequences respectively, and the cyclic shift values ​​of the two cyclic shift sequences have a difference of 6. In addition, when M bit=2, 2-bit UCI 00, 01, 11 and 10 may be mapped to four cyclic shift sequences having a difference of 3 in cyclic shift value, respectively.

[0117] PUCCH format 1 can deliver 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 can be transmitted through continuous OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 can be one of 4 to 14. More specifically, M bit =1 UCI is BPSK modulated. The UE can use quadrature phase shift keying (QPSK) to modulate M bit =2 for UCI. The signal is obtained by multiplying the modulated complex-valued symbol d(0) by a sequence of length 12. In this case, the sequence may be the base sequence for PUCCH format 0. The UE extends the even-numbered OFDM symbols to which PUCCH format 1 is allocated by a time axis orthogonal cover code (OCC) to send the obtained signal. PUCCH format 1 determines the maximum number of different UEs multiplexed in one RB according to the length of the OCC to be used. The demodulation reference signal (DMRS) may be extended with the OCC and mapped to the odd-numbered OFDM symbols of PUCCH format 1.

[0118] PUCCH format 2 can deliver more than 2 bits of UCI. PUCCH format 2 can be sent through one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. When PUCCH format 2 is sent in two OFDM symbols, the sequences sent in different RBs through the two OFDM symbols can be the same as each other. Here, the sequence can be a plurality of modulated complex-valued symbols d(0), ..., d(M symbol -1). Here, M symbol It can be M bit / 2. Through this, the UE can obtain frequency diversity gain. More specifically, for M bit UCI(M bit >2) Perform bit-level scrambling, QPSK modulation, and map it to RBs of one or two OFDM symbols. Here, the number of RBs can be one of 1 to 16.

[0119] PUCCH format 3 or PUCCH format 4 can deliver more than 2 bits of UCI. PUCCH format 3 or PUCCH format 4 can be transmitted through continuous OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 can be one of 4 to 14. Specifically, the UE uses π / 2-binary phase shift keying (BPSK) or QPSK to transmit the OFDM symbol. bit bits UCI (Mbit>2) are modulated to generate complex-valued symbols d(0) to d(M symb -1). Here, when π / 2-BPSK is used, M symb =M bit , and when using QPSK, M symb =M bit / 2. The UE may not apply block unit extension to PUCCH format 3. However, the UE may apply block unit extension to one RB (i.e., 12 subcarriers) using a PreDFT-OCC of length 12, so that PUCCH format 4 may have two or four multiplexing capabilities. The UE performs transmit precoding (or DFT precoding) on ​​the extended signal and maps it to each RE to transmit the extended signal.

[0120] In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 may be determined according to the length of UCI transmitted by the UE and the maximum coding rate. When the UE uses PUCCH format 2, the UE may transmit HARQ-ACK information and CSI information together through the PUCCH. When the number of RBs that the UE may transmit is greater than the maximum number of RBs that may be used by PUCCH format 2, PUCCH format 3, or PUCCH format 4, the UE may not transmit some UCI information according to the priority of the UCI information, but may transmit only the remaining UCI information.

[0121] PUCCH format 1, PUCCH format 3, or PUCCH format 4 may be configured by RRC signaling to indicate frequency hopping in a time slot. When frequency hopping is configured, the index of the RB to be frequency hopped may be configured by RRC signaling. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted by N OFDM symbols of the time axis, the first hop may have floor(N / 2) OFDM symbols and the second hop may have ceiling(N / 2) OFDM symbols.

[0122] PUCCH format 1, PUCCH format 3 or PUCCH format 4 can be configured to be repeatedly transmitted in multiple time slots. In this case, the number K of time slots in which PUCCH is repeatedly transmitted can be configured by RRC signal. The repeatedly transmitted PUCCH must start at an OFDM symbol at a constant position in each time slot and have a constant length. When one OFDM symbol among the OFDM symbols of the time slot in which the UE should transmit the PUCCH is indicated as a DL symbol by RRC signal, the UE may not transmit the PUCCH in the corresponding time slot and delay the transmission of the PUCCH to the next time slot to transmit the PUCCH.

[0123] Meanwhile, in the 3GPP NR system, the UE can perform transmission / reception using a bandwidth equal to or less than the bandwidth of the carrier (or cell). To this end, the UE can receive a bandwidth portion (BWP) of a continuous bandwidth configured with some bandwidths in the carrier bandwidth. A UE operating according to TDD operation or in an unpaired spectrum can receive up to four DL / UL BWP pairs in one carrier (or cell). In addition, the UE can activate one DL / UL BWP pair. A UE operating according to FDD operation or in paired spectrum operation can receive up to four DL BWPs on a DL carrier (or cell) and up to four ULBWPs on a UL carrier (or cell). The UE can activate one DL BWP and one UL BWP for each carrier (or cell). The UE may not perform reception or transmission in time-frequency resources other than the activated BWP. The activated BWP may be referred to as an active BWP.

[0124] The base station may indicate the activated BWP among the BWPs configured by the UE through downlink control information (DCI). The BWP indicated by the DCI is activated, and the other configured BWPs are deactivated. In a carrier (or cell) operating with TDD, the base station may include a bandwidth part indicator (BPI) in the DCI for scheduling PDSCH or PUSCH, which indicates the BWP to be activated to change the DL / UL BWP pair of the UE. The UE may receive the DCI for scheduling PDSCH or PUSCH, and may identify the DL / UL BWP pair activated based on the BPI. For a DL carrier (or cell) operating with FDD, the base station may include a BPI indicating the BWP to be activated in the DCI for scheduling PDSCH to change the DL BWP of the UE. For a UL carrier (or cell) operating with FDD, the base station may include a BPI indicating the BWP to be activated in the DCI for scheduling PUSCH to change the UL BWP of the UE.

[0125] Figure 8 is a conceptual diagram illustrating carrier aggregation.

[0126] Carrier aggregation is a method in which a UE uses multiple frequency blocks or cells (in a logical sense) configured with UL resources (or component carriers) and / or DL ​​resources (or component carriers) as one large logical frequency band so that a wireless communication system uses a wider frequency band. One component carrier may also be referred to as a primary cell (PCell) or a secondary cell (SCell) or a primary SCell (PScell). However, hereinafter, for the convenience of description, the term "component carrier" is used.

[0127] refer to Figure 8 As an example of a 3GPP NR system, the entire system band may include up to 16 component carriers, and each component carrier may have a bandwidth of up to 400 MHz. A component carrier may include one or more physically contiguous subcarriers. Figure 8 In the figure, each component carrier is shown to have the same bandwidth, but this is only an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other on the frequency axis, the drawings are shown in a logical concept, and each component carrier may be physically adjacent to each other, or may be spaced apart.

[0128] A different center frequency may be used for each component carrier. Alternatively, a common center frequency may be used in physically adjacent component carriers. Figure 8 In the embodiment of the present invention, all component carriers are physically adjacent, then the center frequency A can be used in all component carriers. In addition, assuming that the respective component carriers are not physically adjacent to each other, the center frequency A and the center frequency B can be used in each component carrier.

[0129] When the total system frequency band is extended by carrier aggregation, the frequency band used to communicate with each UE can be defined in units of component carriers. UE A can use 100MHz as the total system frequency band and use all five component carriers to perform communication. UE B1~B5 can use only 20MHz bandwidth and use one component carrier to perform communication. UE C1 and C2 can use 40MHz bandwidth and use two component carriers to perform communication respectively. The two component carriers can be logically / physically adjacent or non-adjacent. UE C1 represents the case of using two non-adjacent component carriers, and UE C2 represents the case of using two adjacent component carriers.

[0130] Fig. 9 is a diagram for explaining single carrier communication and multi-carrier communication. In particular, Fig. 9 (a) shows a single carrier subframe structure and Fig. 9 (b) shows a multi-carrier subframe structure.

[0131] refer to Fig. 9 (a), in FDD mode, a general wireless communication system can perform data transmission or reception through a DL frequency band and a UL frequency band corresponding thereto. In another specific embodiment, in TDD mode, a wireless communication system can divide a radio frame into a UL time unit and a DL time unit in the time domain, and perform data transmission or reception through the UL / DL time unit. Fig. 9 (b), three 20MHz component carriers (CCs) can be aggregated into each of UL and DL, so that a bandwidth of 60MHz can be supported. Each CC may be adjacent or non-adjacent to each other in the frequency domain. Fig. 9 (b) shows the case where the bandwidth of the ULCC and the bandwidth of the DL CC are the same and symmetrical, but the bandwidth of each CC can be determined independently. In addition, asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is possible. The DL / UL CC allocated / configured to a specific UE through RRC may be referred to as a serving DL / UL CC for the specific UE.

[0132] The base station can perform communication with the UE by activating some or all of the UE's serving CCs or deactivating some CCs. The base station is able to change the CCs to be activated / deactivated and change the number of CCs to be activated / deactivated. If the base station allocates CCs available to the UE as cell-specific or UE-specific, at least one of the allocated CCs will not be deactivated unless the CC allocation for the UE is completely reconfigured or the UE is switched. One CC that is not deactivated by the UE is called a primary CC (PCC) or a primary cell (PCell), and a CC that the base station can freely activate / deactivate is called a secondary CC (SCC) or a secondary cell (SCell).

[0133] At the same time, 3GPP NR uses the concept of cells to manage radio resources. A cell is defined as a combination of DL resources and UL resources, that is, a combination of DL CCs and UL CCs. A cell may be configured with DL resources alone, or may be configured with a combination of DL resources and UL resources. When carrier aggregation is supported, the link between the carrier frequency of the DL resources (or DL ​​CC) and the carrier frequency of the UL resources (or UL CC) may be indicated by system information. The carrier frequency refers to the center frequency of each cell or CC. The cell corresponding to the PCC is called the PCell, and the cell corresponding to the SCC is called the SCell. The carrier corresponding to the PCell in the DL is the DL PCC, and the carrier corresponding to the PCell in the UL is the UL PCC. Similarly, the carrier corresponding to the SCell in the DL is the DL SCC, and the carrier corresponding to the SCell in the UL is the UL SCC. Depending on the UE capabilities, the serving cell may be configured with one PCell and zero or more SCells. In the case of a UE that is in the RRC_CONNECTED state but is not configured for carrier aggregation or does not support carrier aggregation, only one serving cell is configured with only the PCell.

[0134] As described above, the term "cell" used in carrier aggregation is distinguished from the term "cell" referring to a certain geographical area where communication services are provided by one base station or one antenna group. That is, one component carrier may also be referred to as a scheduling cell, a scheduled cell, a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, in order to distinguish between a cell representing a certain geographical area and a cell of carrier aggregation, in the present disclosure, a cell of carrier aggregation is referred to as a CC, and a cell of a geographical area is referred to as a cell.

[0135] Fig.10 is a diagram showing an example in which cross-carrier scheduling technology is applied. When cross-carrier scheduling is set, the control channel sent through the first CC can use the carrier indicator field (CIF) to schedule the data channel sent through the first CC or the second CC. The CIF is included in the DCI. In other words, a scheduling cell is set, and the DL grant / UL grant sent in the PDCCH area of ​​the scheduling cell schedules the PDSCH / PUSCH of the scheduled cell. That is, there is a search area for multiple component carriers in the PDCCH area of ​​the scheduling cell. The PCell can basically be a scheduling cell, and a specific SCell can be designated as a scheduling cell by an upper layer.

[0136] exist Fig.10In the embodiment of the present invention, it is assumed that three DL CCs are merged. Here, it is assumed that DL component carrier #0 is DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are DL SCC (or SCell). In addition, it is assumed that DL PCC is set as a PDCCH monitoring CC. When cross-carrier scheduling is not configured by UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is disabled, and each DL CC is able to send only the PDCCH for scheduling its PDSCH without CIF according to the NR PDCCH rule (non-cross-carrier scheduling, self-carrier scheduling). At the same time, if cross-carrier scheduling is configured by UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is enabled, and a specific CC (e.g., DL PCC) can use CIF to send not only the PDCCH for scheduling the PDSCH of DL CC A but also the PDCCH for scheduling the PDSCH of another CC (cross-carrier scheduling). On the other hand, PDCCH is not sent in another DL CC. Therefore, the UE monitors a PDCCH not including a CIF to receive a PDSCH scheduled by a self-carrier, or monitors a PDCCH including a CIF to receive a PDSCH scheduled by a cross-carrier, according to whether cross-carrier scheduling is configured for the UE.

[0137] on the other hand, Fig. 9 and Fig.10 The subframe structure of the 3GPP LTE-A system is shown in the figure, and the same or similar configuration can be applied to the 3GPP NR system. However, in the 3GPP NR system, Fig. 9 and Fig.10 The subframes may be replaced by time slots.

[0138] Fig.11 The diagram illustrates the code block group (CBG) configuration and its time-frequency resource mapping according to an embodiment of the present invention. More specifically, Fig.11 (a) illustrates an embodiment of a CBG configuration included in one transport block (TB), and Fig.11 (b) illustrates the time-frequency resource mapping of the CBG configuration.

[0139] The channel code defines the maximum supported length. For example, the maximum supported length of the turbo code used in 3GPP LTE(-A) is 6144 bits. However, the length of the transport block (TB) sent on the PDSCH may be longer than 6144 bits. If the length of the TB is greater than the maximum supported length, the TB can be divided into code blocks (CBs) with a maximum length of 6144 bits. Each CB is a unit in which channel coding is performed. In addition, for efficient retransmission, several CBs can be grouped to configure one CBG. The UE and the base station need information on how to configure the CBG.

[0140] The CBGs and CBs within a TB may be configured according to various embodiments. According to an embodiment, the number of available CBGs may be determined as a fixed value, or may be configured with RRC configuration information between a base station and a UE. In this case, the number of CBs is determined by the length of the TB, and the CBG may be configured depending on information of the determined number. According to another embodiment, the number of CBs to be included in one CBG may be determined as a fixed value, or may be configured with RRC configuration information between a base station and a UE. In this case, if the number of CBs is determined by the length of the TB, the number of CBGs may be configured depending on information about the number of CBs for each CBG.

[0141] refer to Fig.11 (a) Embodiment, a TB can be divided into eight CBs. The eight CBs can be grouped into four CBGs again. The mapping relationship (or CBG configuration) between the CB and the CBG can be statically configured between the base station and the UE, or can be semi-statically established using RRC configuration information. According to another embodiment, the mapping relationship can be configured by dynamic signaling. When the UE receives the PDCCH sent by the base station, the UE can directly or indirectly identify the mapping relationship (or CBG configuration) between the CB and the CBG through explicit information and / or implicit information. A CBG may contain only one CB, or may include all CBs constituting a TB. For reference, the techniques presented in the embodiments of the present invention can be applied regardless of the configuration of the CB and the CBG.

[0142] refer to Fig.11 (b) Map the CBGs constituting one TB to the time-frequency resources scheduled by the PDSCH. According to an embodiment, each CBG may be first allocated on the frequency axis and then extended on the time axis. When a PDSCH consisting of one TB including four CBGs is allocated to seven OFDM symbols, CBG0 may be sent on the first and second OFDM symbols, CBG1 may be sent on the second, third and fourth OFDM symbols, CBG2 may be sent on the fourth, fifth, and sixth OFDM symbols, and CBG3 may be sent on the sixth and seventh OFDM symbols. The time-frequency mapping relationship allocated by CBG and PDSCH may be determined between the base station and the UE. However, Fig.11 The mapping relationship illustrated in (b) is used to describe an embodiment of the present invention, and the techniques presented in the embodiments of the present invention can be applied regardless of the time-frequency mapping relationship of CBG.

[0143] Fig.12 The figure illustrates a process in which a base station performs TB-based transmission or CBG-based transmission, and a UE sends a HARQ-ACK in response thereto. Fig.12, the base station can configure a transmission scheme suitable for the UE for TB-based transmission and CBG-based transmission. The UE can send HARQ-ACK information bits through PUCCH or PUSCH according to the transmission scheme configured by the base station. The base station can configure the PDCCH to schedule the PDSCH to be sent to the UE. The PDCCH can schedule TB-based transmission and / or CBG-based transmission. For example, one TB or two TBs can be scheduled on the PDCCH. If one TB is scheduled, the UE must feedback 1-bit HARQ-ACK. If two TBs are scheduled, a 2-bit HARQ-ACK must be fed back for each of the two TBs. In order to eliminate ambiguity between the base station and the UE, there may be a predetermined order between each information bit of the 2-bit HARQ-ACK and the two TBs. For reference, when the MIMO transmission rank or layer is low, one TB can be sent on one PDSCH, and when the MIMO transmission rank or layer is high, two TBs can be sent on one PDSCH.

[0144] The UE may send a 1-bit TB-based HARQ-ACK for each TB to inform the base station whether the reception of each TB is successful. In order to generate a HARQ-ACK for one TB, the UE may check the reception error of the TB through the TB-CRC. When the TB-CRC for the TB is successfully checked, the UE generates an ACK for the HARQ-ACK for the TB. However, if a TB-CRC error occurs for the TB, the UE generates a NACK for the HARQ-ACK for the TB. The UE sends the TB-based HARQ-ACK generated as described above to the base station. The base station resends the TB that was responded with a NACK in the TB-based HARQ-ACK received from the UE.

[0145] In addition, the UE may send a 1-bit CBG-based HARQ-ACK for each CBG to inform the base station whether the reception of each CBG is successful. In order to generate a HARQ-ACK for one CBG, the UE may decode all CBs included in the CBG and check the reception error of each CB through the CB-CRC. When the UE successfully receives all CBs constituting a CBG (ie, when all CB-CRCs are successfully checked), the UE generates an ACK for the HARQ-ACK of the CBG. However, when the UE does not successfully receive at least one of the CBs constituting a CBG (ie, when at least one CB-CRC error occurs), the UE generates a NACK for the HARQ-ACK of the CBG. The UE sends the CBG-based HARQ-ACK generated as described above to the base station. The base station retransmits the CBG that was responded to with a NACK among the CBG-based HARQ-ACK received from the UE. According to an embodiment, the CB configuration of the retransmitted CBG may be the same as the CB configuration of the previously transmitted CBG. The length of the CBG-based HARQ-ACK information bits sent by the UE to the base station can be determined based on the number of CBGs sent through the PDSCH or the maximum number of CBGs configured with the RRC signal.

[0146] On the other hand, even when the UE successfully receives all CBGs included in the TB, a TB-CRC error may occur for the TB. In this case, the UE can perform a flip of the CBG-based HARQ-ACK to request retransmission for the TB. That is, even if all CBGs included in the TB are successfully received, the UE can generate all CBG-based HARQ-ACK information bits as NACK. Upon receiving CBG-based HARQ-ACK feedback in which all HARQ-ACK information bits are NACK, the base station resends all CBGs of the TB.

[0147] According to an embodiment of the present invention, CBG-based HARQ-ACK feedback can be used for successful transmission of a TB. The base station may instruct the UE to send a CBG-based HARQ-ACK. In this case, a retransmission technique based on the CBG-based HARQ-ACK may be used. The CBG-based HARQ-ACK may be sent via the PUCCH. In addition, when the UCI is configured to be sent via the PUSCH, the CBG-based HARQ-ACK may be sent via the PUSCH. In the PUCCH, the configuration of the HARQ-ACK resources may be configured via an RRC signal. In addition, the HARQ-ACK resources actually sent may be indicated by the PDCCH that schedules the PDSCH sent based on the CBG. The UE may send a HARQ-ACK for whether the sent CBG is successfully received through a PUCCH resource indicated by the PDCCH among the PUCCH resources configured with the RRC.

[0148] The base station can identify whether the UE has successfully received the CBG sent to the UE through the UE's CBG-based HARQ-ACK feedback. That is, through the HARQ-ACK for each CBG received from the UE, the base station can identify the CBG that the UE has successfully received and the CBG that the UE has failed to receive. The base station can perform CBG retransmission based on the received CBG-based HARQ-ACK. More specifically, the base station can bundle and retransmit only the CBG in response to the failed HARQ-ACK in one TB. In this case, the CBG in response to the successfully received HARQ-ACK is excluded from the retransmission. The base station can schedule the retransmitted CBG as a PDSCH and send it to the UE.

[0149] <Communication Method in Unlicensed Band>

[0150] Fig.13 Figure 1 shows the service environment of New Radio Unlicensed (NR-U).

[0151] refer to Fig.13 , a service environment of NR technology 11 in the existing licensed band and unlicensed NR (NR-U) (i.e., NR technology 12 in the unlicensed band) can be provided to users. For example, in the NR-U environment, technologies such as carrier aggregation can be used to integrate NR technology 11 in the licensed band and NR technology 12 in the unlicensed band, which can contribute to the expansion of network capacity. In addition, in an asymmetric service structure with more downlink data than uplink data, NR-U can provide NR services optimized for various needs or environments. For convenience, the NR technology in the licensed band is referred to as NR-L (licensed NR), and the NR technology in the unlicensed band is referred to as NR-U (unlicensed NR).

[0152] Fig.14 The figure shows the deployment scenario of user equipment and base stations in the NR-U service environment. Due to the high frequency characteristics, the radio communication range of the frequency band targeted by the NR-U service environment is short. Taking this into account, in an environment where the existing NR-L service and NR-U service coexist, the deployment scenario of the user equipment and base station can be a coverage model or a co-location model.

[0153] In the coverage model, the macro base station can perform wireless communication with X UE and X'UE in the macro area (32) by using a licensed carrier, and connect with multiple radio remote heads (RRHs) through an X2 interface. Each RRH can perform wireless communication with X UE or X'UE in a predetermined area (31) by using an unlicensed carrier. The frequency bands of the macro base station and the RRH are different from each other to avoid mutual interference, but data needs to be quickly exchanged between the macro base station and the RRH through the X2 interface in order to use the NR-U service as an auxiliary downlink channel for the NR-L service through carrier aggregation.

[0154] In the co-location model, the pico / femto base station can perform wireless communication with the YUE by using both licensed carriers and unlicensed carriers. However, it may be limited by the pico / femto base station using both NR-L service and NR-U service for downlink transmission. The coverage range (33) of the NR-L service and the coverage range (34) of the NR-U service may be different according to the frequency band, transmission power, etc.

[0155] When NR communication is performed in an unlicensed band, a legacy device (e.g., a wireless LAN (Wi-Fi) device) that performs communication in the corresponding unlicensed band may not demodulate the NR-U message or data. Therefore, the legacy device determines the NR-U message or data as a type of energy to perform interference avoidance operations through energy detection technology. That is, when the energy corresponding to the NR-U message or data is lower than -62dBm or a certain energy detection (ED) threshold, the wireless LAN device can perform communication by ignoring the corresponding message or data. As a result, user equipment performing NR communication in an unlicensed band may often be interfered with by wireless LAN devices.

[0156] Therefore, it is necessary to allocate or reserve a specific frequency band at a specific time in order to effectively implement NR-U technology / services. However, because peripheral devices that perform communication through unlicensed bands attempt to access based on energy detection technology, there is a problem that it is difficult to perform efficient NR-U services. Therefore, in order to solve the NR-U technology, it is necessary to give priority to studying coexistence schemes with traditional unlicensed band devices and schemes for effectively sharing radio channels. That is, it is necessary to develop a robust coexistence mechanism in which NR-U devices do not affect traditional unlicensed band devices.

[0157] Fig.15 A conventional communication scheme (eg, wireless LAN) operating in an unlicensed band is illustrated. Since most devices operating in an unlicensed band operate based on "listen before talk" (LBT), a clear communication channel assessment (CCA) technique of sensing a channel before data transmission is performed.

[0158] refer to Fig.15 , a wireless LAN device (e.g., an AP or STA) checks whether a channel is busy by performing carrier sensing before sending data. When a radio signal of a predetermined strength or higher is sensed in a channel to send data, it is determined that the corresponding channel is busy, and the wireless LAN device delays access to the corresponding channel. Such a process is called clear channel assessment, and the signal level used to decide whether a signal is sensed is called a CCA threshold. At the same time, when no radio signal is sensed in the corresponding channel or when a radio signal with a strength less than the CCA threshold is sensed, the channel is determined to be idle.

[0159] When it is determined that the channel is idle, the terminal with data to be sent performs a backoff process after a deferral duration (e.g., arbitration interframe space (AIFS), PCF IFS (PIFS), etc.). The deferral duration indicates the shortest time the terminal needs to wait after the channel is idle. The backoff process allows the terminal to further wait for a predetermined time after the deferral duration. For example, the terminal prepares while reducing the time slot time corresponding to the random number allocated to the terminal during the channel idle period in the contention window (CW), and the terminal that completely exhausts the time slot time can attempt to access the corresponding channel.

[0160] When the terminal successfully accesses the channel, the terminal can send data through the channel. After the data is successfully sent, the CW size (CWS) will be reset to the initial value (CWmin). On the contrary, when the data is not successfully sent, the CWS is increased by two times. As a result, a new random number is assigned to the terminal within a range that is twice larger than the previous random number range to perform a fallback process in the next CW. In a wireless LAN, only ACK is defined as receiving response information to data transmission. Therefore, when ACK is received with respect to data transmission, CWS is reset to the initial value, and when no feedback information is received with respect to data transmission, CWS is increased by two times.

[0161] As mentioned above, since existing communications in unlicensed bands are mainly operated based on LBT, channel access in the NR-U system also performs LBT to coexist with existing devices. Specifically, according to the presence / absence / application method of LBT, channel access methods on unlicensed bands in NR can be classified into the following four categories.

[0162] ●Category 1: No LBT

[0163] - The Tx entity does not perform the LBT procedure for transmission.

[0164] ●Category 2: LBT without random fallback

[0165] -The Tx entity senses whether the channel is idle during the first interval to perform transmission without random backoff. That is, the Tx entity may perform transmission through the channel immediately after sensing that the channel is idle during the first interval. The first interval is an interval of a predetermined length immediately before the Tx entity performs transmission. According to an embodiment, the first interval may be an interval of 25 μs in length, but the present invention is not limited thereto.

[0166] ● Category 3: LBT with random backoff using fixed-size CW

[0167] -The Tx entity obtains a random value within the fixed size CW, sets it as the initial value N of the backoff counter (or backoff timer), and performs backoff by using the set backoff counter N. In the backoff process, whenever the channel is detected to be in an idle state within a predetermined time slot period, the Tx entity reduces the backoff counter by 1. Here, the predetermined time slot period may be 9 μs, but the present invention is not limited thereto. The backoff counter N is reduced by 1 from the initial value, and when the value of the backoff counter N reaches 0, the Tx entity may perform transmission. At the same time, in order to perform backoff, the Tx entity first senses the first time interval (i.e., the delay duration T d ) during the second interval. According to an embodiment of the present invention, the Tx entity can sense (determine) whether the channel is idle during the second interval based on whether the channel is idle in at least some time periods (e.g., a time slot period) within the second interval. The second interval can be set based on the channel access priority level of the Tx entity and consists of a period of 16μs and m consecutive time slot periods. Here, m is a value set according to the channel access priority category. When the channel is sensed to be idle during the second interval, the Tx entity performs channel sensing to reduce the backoff counter. On the other hand, when the channel is sensed to be busy during the backoff process, the backoff process stops. After stopping the backoff process, when it is sensed that the channel is idle in the additional second interval, the Tx entity can resume the backoff. In this way, in addition to the second interval, the Tx entity can also perform transmission when the channel is idle during the time slot period of the backoff counter N. In this case, the initial value of the backoff counter N is obtained within a CW of a fixed size.

[0168] ● Category 4: LBT performs random backoff by using variable-sized CWs

[0169] -The Tx entity obtains a random value within a variable-sized CW, sets the random value as an initial value of a backoff counter (or backoff timer) N, and performs backoff by using the set backoff counter N. More specifically, the Tx entity may adjust the size of the CW based on the HARQ-ACK information for the previous transmission, and obtain the initial value of the backoff counter N within the CW of the adjusted size. The specific process of performing backoff by the Tx entity is as described in Category 3. In addition to the second interval, the Tx entity may perform transmission when the channel is idle during the time slot period of the backoff counter N. In this case, the initial value of the backoff counter N is obtained within the variable-sized CW.

[0170] In the above categories 1 to 4, the Tx entity may be a base station or a UE. According to an embodiment of the present invention, the first type of channel access may refer to category 4 channel access, and the second type of channel access may refer to category 2 channel access.

[0171] Fig.16 The diagram illustrates a channel access process based on Category 4 LBT according to an embodiment of the present invention.

[0172] To perform channel access, first, the Tx entity defers for a duration T d Channel sensing is performed within the delay time T (step S302). d The delay duration T in step S302 is performed by channel sensing within at least a portion of d For example, the channel sensing for the postponement duration Td may be performed by channel sensing during a time slot period within the postponement duration Td. d The Tx entity performs channel sensing within the delay duration T d The channel is sensed to check whether the channel is idle (step S304). d If the channel is idle within the delay time T, the Tx entity proceeds to step S306. d If the channel is not sensed to be idle (i.e., busy) within the delay time T, the Tx entity returns to step S302. The Tx entity repeats steps S302 to S304 until the delay time T is reached. d The delay duration T can be set based on the channel access priority level of the Tx entity. d , and the delay duration is T d It consists of a 16 μs period and m consecutive time slot periods. Here, m is a value set according to the channel access priority level.

[0173] Next, the Tx entity obtains a random value within a predetermined CW, sets the random value as the initial value N of the backoff counter (or backoff timer) (step S306), and proceeds to step S308. The initial value of the backoff counter N is randomly selected from a value between 0 and CW. The Tx entity performs the backoff process by using the set backoff counter N. That is, the Tx entity performs the backoff process by repeating steps S308 to S316 until the value of the backoff counter N reaches 0. Fig.16 The figure shows that the channel is sensed after a delay of duration T d Step S306 is performed after the channel is idle for a period of time T, but the present invention is not limited thereto. That is, step S306 can be performed independently of steps S302 to S304, and can be performed before steps S302 to S304. When step S306 is performed before steps S302 to S304, if the channel is sensed by steps S302 to S304 to be idle for a period of time T, then the channel is idle for a period of time T. d If the Tx entity is idle, it proceeds to step S308.

[0174] In step S308, the Tx entity checks whether the value of the backoff counter N is 0. If the value of the backoff counter N is 0, the Tx entity proceeds to step S320 to perform transmission. If the value of the backoff counter N is not 0, the Tx entity proceeds to step S310. In step S310, the Tx entity reduces the value of the backoff counter N by 1. According to an embodiment, the Tx entity may selectively reduce the value of the backoff counter by 1 during the channel sensing process of each time slot. In this case, step S310 may be skipped at least once by the selection of the Tx entity. Next, the Tx entity performs channel sensing on the additional time slot period (step S312). The Tx entity checks whether the channel is idle by channel sensing within the additional time slot period (step S314). If it is sensed that the channel is idle within the additional time slot period, the Tx entity returns to step S308. In this way, whenever the channel is sensed to be idle within a predetermined time slot period, the Tx entity may reduce the backoff counter by 1. Here, the predetermined time slot period may be 9 μs, but the present invention is not limited thereto.

[0175] In step S314, if the channel is not sensed to be idle (ie, sensed to be busy) during the additional time slot period, the Tx entity proceeds to step S316. In step S316, the Tx entity checks whether the channel is idle during the additional deferral duration T d According to an embodiment of the present invention, the channel sensing in step S316 may be performed in units of time slots. That is, the Tx entity checks whether the additional delay duration T d Whether the channel is sensed to be idle during all time slot periods. dWhen a busy time slot is detected within the additional delay time T, the Tx entity immediately restarts step S316. d When the channel is sensed to be idle during all time slot periods, the Tx entity returns to step S308.

[0176] On the other hand, if the value of the backoff counter N is 0 in the check of step S308, the Tx entity performs the transmission (step S320). The Tx entity receives the HARQ-ACK feedback corresponding to the transmission (step S322). The Tx entity can check whether the previous transmission is successful through the received HARQ-ACK feedback. Next, the Tx entity adjusts the CW size for the next transmission based on the received HARQ-ACK feedback (step S324).

[0177] As mentioned above, after sensing the channel for a delay duration T d After being idle for N additional time slots, the Tx entity may perform transmission when the channel is idle for N additional time slots. As described above, the Tx entity may be a base station or a UE, and Fig.16 The channel access procedure may be used for downlink transmission of a base station and / or uplink transmission of a UE.

[0178] In the following, a method for adaptively adjusting CWS when accessing a channel in an unlicensed band is proposed. The CWS may be adjusted based on UE (user equipment) feedback, and the UE feedback for CWS adjustment may include HARQ-ACK feedback and CQI / PMI / RI. In the present invention, a method for adaptively adjusting CWS based on HARQ-ACK feedback is proposed. The HARQ-ACK feedback includes at least one of ACK, NACK, DTX, and NACK / DTX.

[0179] As described above, even in wireless LAN systems, CWS is adjusted based on ACK. When ACK feedback is received, CWS is reset to the minimum value (CWmin), and when ACK feedback is not received, CWS is increased. However, in cellular systems, a CWS adjustment method that considers multiple access is required.

[0180] First, in order to describe the present invention, terms are defined as follows.

[0181] -A set of HARQ-ACK feedback values ​​(i.e., a HARQ-ACK feedback set): refers to a HARQ-ACK feedback value used for CWS update / adjustment. The HARQ-ACK feedback set is decoded when determining the CWS and corresponds to an available HARQ-ACK feedback value. The HARQ-ACK feedback set includes HARQ-ACK feedback values ​​for one or more DL (channel) transmissions (e.g., PDSCH) on an unlicensed band carrier (e.g., Scell, NR-U cell). The HARQ-ACK feedback set may include HARQ-ACK feedback values ​​for DL ​​(channel) transmissions (e.g., PDSCH), for example, multiple HARQ-ACK feedback values ​​fed back from multiple UEs. The HARQ-ACK feedback value may indicate reception response information for a code block group (CBG) or a transport block (TB), and may indicate any of ACK, NACK, DTX, or NACK / DTX. Depending on the context, the HARQ-ACK feedback value may be mixed with terms such as HARQ-ACK value, HARQ-ACK information bit, and HARQ-ACK response.

[0182] - Reference window: refers to the time interval during which DL transmission (e.g., PDSCH) corresponding to the HARQ-ACK feedback set is performed in an unlicensed carrier (e.g., Scell, NR-U cell). According to an embodiment, the reference window may be defined in units of time slots or subframes. The reference window may indicate one or more specific time slots (or subframes). According to an embodiment of the present invention, a specific time slot (or reference time slot) may include the start time slot of the most recent DL transmission burst, where at least some HARQ-ACK feedback is expected to be available.

[0183] Fig.17 An embodiment of a method for adjusting the contention window size (CWS) based on HARQ-ACK feedback is illustrated. Fig.17 In the embodiment of the present invention, the Tx entity may be a base station, and the Rx entity may be a UE, but the present invention is not limited thereto. Fig.17 The embodiments assume a channel access procedure for DL ​​transmission of a base station, but at least some configurations may be applied to a channel access procedure for UL transmission of a UE.

[0184] refer to Fig.17 , the Tx entity sends an nth DL transmission burst on an unlicensed band carrier (e.g., Scell, NR-U cell) (step S402), and then, if additional DL transmission is required, the Tx entity may send an (n+1)th DL transmission burst based on LBT channel access (step S412). Here, the transmission burst indicates transmission through one or more adjacent time slots (or subframes). Fig.17The figure illustrates a channel access process and a CWS adjustment method based on the above-mentioned first type of channel access (ie, category 4 channel access).

[0185] First, the Tx entity receives HARQ-ACK feedback corresponding to PDSCH transmission on an unlicensed band carrier (e.g., Scell, NR-U cell) (step S404). The HARQ-ACK feedback for CWS adjustment includes HARQ-ACK feedback corresponding to the most recent DL transmission burst (i.e., the nth DL transmission burst) on the unlicensed band carrier. More specifically, the HARQ-ACK feedback for CWS adjustment includes HARQ-ACK feedback corresponding to the PDSCH transmission on the reference window within the most recent DL transmission burst. The reference window may indicate one or more specific time slots (or subframes). According to an embodiment of the present invention, a specific time slot (or reference time slot) includes the starting time slot of the most recent DL transmission burst, where at least some HARQ-ACK feedback is expected to be available.

[0186] When HARQ-ACK feedback is received, a HARQ-ACK value is obtained for each transport block (TB). The HARQ-ACK feedback includes at least one of a HARQ-ACK bit sequence based on the TB and a HARQ-ACK based on the CBG. When the HARQ-ACK feedback is a HARQ-ACK bit sequence based on the TB, one HARQ-ACK information bit is obtained for each TB. On the other hand, when the HARQ-ACK feedback is a HARQ-ACK bit sequence based on the CBG, N HARQ-ACK information bits are obtained for each TB. Here, N is the maximum number of CBGs per TB configured in the Rx entity of the PDSCH transmission. According to an embodiment of the present invention, the HARQ-ACK value of each TB can be determined using the HARQ-ACK information bit of each TB of the HARQ-ACK feedback determined by the CWS. More specifically, when the HARQ-ACK feedback is a HARQ-ACK bit sequence based on the TB, one HARQ-ACK information bit of the TB is determined as the HARQ-ACK value. However, when the HARQ-ACK feedback is a HARQ-ACK bit sequence based on the CBG, a HARQ-ACK value may be determined based on N HARQ-ACK information bits corresponding to the CBG included in the TB.

[0187] Next, the Tx entity adjusts the CWS based on the HARQ-ACK value determined in step S404 (step S406). That is, the Tx entity determines the CWS based on the HARQ-ACK value determined using the HARQ-ACK information bit for each TB of HARQ-ACK feedback. More specifically, the CWS can be adjusted based on the ratio of NACKs among the HARQ-ACK values. First, the variables can be defined as follows.

[0188] -p: priority level value

[0189] -CW_min_p: The predetermined minimum CWS value for priority level p

[0190] -CW_max_p: the predetermined CWS maximum value for priority level p

[0191] - CW_p: CWS used to transmit priority level p. CW_p is set to any one of a plurality of CWS values ​​between CW_min_p and CW_max_p included in the allowed CWS set for priority level p.

[0192] According to an embodiment of the present invention, the CWS may be determined according to the following steps.

[0193] Step A-1) For each priority level p, set CW_p to CW_min_p. In this case, priority levels p include {1, 2, 3, 4}.

[0194] Step A-2) When the ratio of NACK among the HARQ-ACK values ​​of the PDSCH transmission of the reference window k is Z% or higher, for each priority level p, CW_p is increased to the next highest allowed value (further, remain in step A-2). Otherwise, step A proceeds to step A-1. Here, Z is a predetermined integer in the range of 0≤Z≤100, and according to an embodiment, it can be set to one of {30, 50, 70, 80, 100}.

[0195] Here, reference window k includes the start timeslot (or subframe) of the most recent transmission by the Tx entity. In addition, reference window k is the timeslot (or subframe) in which at least some HARQ-ACK feedback expectations are possible. If CW_p = CW_max_p, then the next highest allowed value for CW_p adjustment is CW_max_p.

[0196] Next, the Tx entity selects a random value within the CWS determined in step S406 and sets the random value as the initial value of the backoff counter N (step S408). The Tx entity performs backoff by using the set backoff counter N (step S410). That is, for each time slot period in which the channel is sensed to be idle, the Tx entity may reduce the backoff counter by 1. When the value of the backoff counter reaches 0, the Tx entity may send the (n+1)th DL transmission burst in the channel (step S412).

[0197] Meanwhile, in the above-mentioned CWS adjustment process, it has to be determined whether not only ACK and NACK but also DTX or NACK / DTX are considered in the HARQ-ACK feedback. According to an embodiment of the present invention, depending on whether the transmission in the unlicensed band is based on self-carrier scheduling or cross-carrier scheduling, it can be determined whether DTX or NACK / DTX is considered together in the CWS adjustment process.

[0198] In self-carrier scheduling, DL transmission (e.g., PDSCH) on an unlicensed band carrier is scheduled by a control channel (e.g., (E)PDCCH) sent on the same unlicensed band carrier. Here, because DTX indicates that DL transmission by a hidden node or the like in an unlicensed band carrier has failed, it can be used together with NACK for CWS adjustment. In addition, DTX is one of the methods in which the UE notifies the base station that the UE has failed to decode the control channel even though the base station has sent a control channel including scheduling information (e.g., (E)PDCCH) to the UE. DTX can be determined only by the HARQ-ACK feedback value, or can be determined by considering the HARQ-ACK feedback value and the actual scheduling situation. According to an embodiment of the present invention, in the case of self-carrier scheduling, DTX and NACK / DTX can be counted as NACKs for CWS adjustment. That is, when the ratio of the sum of NACK, DTX, and NACK / DTX among the HARQ-ACK values ​​for PDSCH transmission of reference window k is equal to or greater than Z%, CWS increases to the next highest allowed value. Otherwise, CWS will be reset to the minimum value.

[0199] In cross-carrier scheduling, DL transmission (e.g., PDSCH) on an unlicensed band carrier can be scheduled by a control channel (e.g., (E)PDCCH) sent on a licensed band carrier. In this case, because DTX feedback is used to determine the decoding of the UE for the control channel sent on the licensed band carrier, it is not helpful to adaptively adjust the CWS for channel access in the unlicensed band. Therefore, according to an embodiment of the present invention, in the case of cross-carrier scheduling from the licensed band, DTX can be ignored for CWS determination. That is, for CWS adjustment, among the HARQ-ACK values, only ACK and NACK can be considered to calculate the ratio of NACK, or only ACK, NACK and NACK / DTX can be considered to calculate the ratio of NACK. Therefore, when calculating the ratio of NACK, DTX can be excluded.

[0200] Fig.18is a block diagram showing the configuration of a UE and a base station according to an embodiment of the present invention. In an embodiment of the present disclosure, the UE can be implemented using various types of wireless communication devices or computing devices that ensure portability and mobility. The UE may be referred to as a user equipment (UE), a station (STA), a mobile subscriber (MS), and the like. In addition, in an embodiment of the present invention, the base station controls and manages cells (e.g., macro cells, femto cells, micro cells, etc.) corresponding to a service area, and performs functions such as signal transmission, channel designation, channel monitoring, self-diagnosis, relaying, and the like. The base station may be referred to as a next generation Node B (gNB) or an access point (AP).

[0201] As shown in the drawings, the UE 100 according to an embodiment of the present disclosure may include a processor 110 , a communication module 120 , a memory 130 , a user interface 140 , and a display unit 150 .

[0202] First, the processor 100 may execute various instructions or programs within the UE 100 and process data. In addition, the processor 110 may control the entire operation of each unit including the UE 100, and may control the transmission / reception of data between the units. Here, the processor 110 may be configured to perform operations according to the embodiments described in the present invention. For example, the processor 110 may receive time slot configuration information, determine the time slot configuration based on the time slot configuration information, and perform communication according to the determined time slot configuration.

[0203] Next, the communication module 120 may be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 120 may include a plurality of network interface cards (NICs) such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123 in an internal or external form. In the drawings, the communication module 120 is shown as an integrally integrated module, but unlike the drawings, each network interface card can be independently arranged according to a circuit configuration or usage.

[0204] The cellular communication interface card 121 may send or receive a radio signal with at least one of the base station 200, the external device, and the server by using a mobile communication network and provide a cellular communication service in a first frequency band based on an instruction from the processor 110. According to an embodiment, the cellular communication interface card 121 may include at least one NIC module using a frequency band less than 6 GHz. At least one NIC module of the cellular communication interface card 121 may independently perform cellular communication with at least one of the base station 200, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band below 6 GHz supported by the corresponding NIC module.

[0205] The cellular communication interface card 122 may send or receive a radio signal with at least one of the base station 200, the external device, and the server by using a mobile communication network and provide a cellular communication service in the second frequency band based on an instruction from the processor 110. According to an embodiment, the cellular communication interface card 122 may include at least one NIC module using a frequency band greater than 6 GHz. At least one NIC module of the cellular communication interface card 122 may independently perform cellular communication with at least one of the base station 200, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band greater than 6 GHz supported by the corresponding NIC module.

[0206] The unlicensed band communication interface card 123 transmits or receives a radio signal with at least one of the base station 200, the external device, and the server by using the third frequency band as the unlicensed frequency band, and provides an unlicensed frequency band communication service based on an instruction from the processor 110. The unlicensed band communication interface card 123 may include at least one NIC module using the unlicensed frequency band. For example, the unlicensed frequency band may be a frequency band above 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or 52.6 GHz. At least one NIC module of the unlicensed band communication interface card 123 may independently or non-independently perform wireless communication with at least one of the base station 200, the external device, and the server according to the unlicensed frequency band communication standard or protocol of the frequency band supported by the corresponding NIC module.

[0207] The memory 130 stores a control program and various data thereof used in the UE 100. Such a control program may include a prescribed program required to perform wireless communication with at least one of the base station 200, an external device, and a server.

[0208] Next, the user interface 140 includes various input / output means provided in the UE 100. In other words, the user interface 140 may receive user input using various input means, and the processor 110 may control the UE 100 based on the received user input. In addition, the user interface 140 may perform output based on instructions from the processor 110 using various output means.

[0209] Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects such as content or a user interface executed by the processor 110 based on a control instruction from the processor 110.

[0210] In addition, the base station 200 according to the embodiment of the present invention may include a processor 210 , a communication module 220 , and a memory 230 .

[0211] First, the processor 210 may execute various instructions or programs and process the internal data of the base station 200. In addition, the processor 210 may control the entire operation of each unit in the base station 200 and control the transmission and reception of data between the units. Here, the processor 210 may be configured to perform the operations according to the embodiments described in the present invention. For example, the processor 210 may signal a time slot configuration and perform communication according to the time slot configuration notified by the signal.

[0212] Next, the communication module 220 may be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 220 may include a plurality of network interface cards such as cellular communication interface cards 221 and 222 and an unlicensed band communication interface card 223 in an internal or external form. In the drawings, the communication module 220 is shown as an integrally integrated module, but unlike the drawings, each network interface card can be independently arranged according to a circuit configuration or usage.

[0213] The cellular communication interface card 221 may send or receive a radio signal with at least one of the UE 100, the external device, and the server by using a mobile communication network and provide a cellular communication service in a first frequency band based on an instruction from the processor 210. According to an embodiment, the cellular communication interface card 221 may include at least one NIC module using a frequency band less than 6 GHz. At least one NIC module of the cellular communication interface card 221 may independently perform cellular communication with at least one of the UE 100, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band less than 6 GHz supported by the corresponding NIC module.

[0214] The cellular communication interface card 222 may send or receive a radio signal with at least one of the UE 100, the external device, and the server by using a mobile communication network and provide a cellular communication service in the second frequency band based on an instruction from the processor 210. According to an embodiment, the cellular communication interface card 222 may include at least one NIC module using a frequency band of 6 GHz or higher. At least one NIC module of the cellular communication interface card 222 may independently perform cellular communication with at least one of the UE 100, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band of 6 GHz or higher supported by the corresponding NIC module.

[0215] The unlicensed band communication interface card 223 transmits or receives a radio signal with at least one of the UE 100, the external device, and the server by using a third frequency band as an unlicensed frequency band, and provides an unlicensed frequency band communication service based on an instruction from the processor 210. The unlicensed band communication interface card 223 may include at least one NIC module using an unlicensed frequency band. For example, the unlicensed frequency band may be a frequency band above 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or 52.6 GHz. At least one NIC module of the unlicensed band communication interface card 223 may independently or dependently perform wireless communication with at least one of the UE 100, the external device, and the server in accordance with an unlicensed frequency band communication standard or protocol of a frequency band supported by the corresponding NIC module.

[0216] Fig.18 1 is a block diagram illustrating a UE 100 and a base station 200 according to an embodiment of the present invention, and the blocks shown separately are logically divided elements of the device. Therefore, the aforementioned elements of the device can be installed in a single chip or multiple chips according to the design of the device. In addition, a part of the configuration of the UE 100, for example, a user interface 140, a display unit 150, etc., can be selectively provided in the UE 100. In addition, the user interface 140, the display unit 150, etc. can be additionally provided in the base station 200 when necessary.

[0217] Fig.19 is a flowchart illustrating an example of a method of transmitting uplink data in an unlicensed band according to an embodiment of the present invention.

[0218] refer to Fig.19 , the UE performs channel sensing in a BWP activated to transmit a physical uplink shared channel (PUSCH) in an unlicensed band, and when the sensed channel is in an idle state, transmits the PUSCH to the base station in the channel in the idle state.

[0219] Specifically, in S19010, the UE receives an RRC configuration (Radio Resource Control Configuration) including information for receiving downlink control information and information for PUSCH transmission from the base station.

[0220] At S19020, the UE may receive downlink control information (DCI) based on the information included in the received RRC configuration.

[0221] The DCI may include resource allocation information related to resources allocated for PUSCH transmission, configuration information related to a reference signal, and the like.

[0222] In addition, when there are multiple BWPs, the DCI may further include an indicator indicating a BWP that is activated to transmit a PUSCH by the UE and information related to a subband in which the reference signaling is performed when uplink data is transmitted in an unlicensed band. Fig.15 The LBT operation of the channel sensing is described.

[0223] At this time, subbands may be continuously allocated, and information on the continuously allocated subbands may be included in the DCI through a RIV (Resource Information Value) scheme.

[0224] In addition, PRBs as resource blocks (RBs) included in the activated BWP can be included in the BWP in an interleaved structure, where mapping is performed at regular intervals, and resource allocation information related to the PRBs as allocated resources can be included in the DCI through RIV or a bitmap scheme.

[0225] The RIV scheme refers to a method of inserting the start index of the allocated resources and the length information of the allocated resources into the DCI and notifying the UE so that the UE recognizes the allocated resources, and the bitmap scheme refers to a method of indicating the detailed location of the allocated resources through bits.

[0226] In the following, reference will be made to Figure 20 to Figure 22 , describes in detail a method of inserting information related to subbands and allocated resources into DCI.

[0227] Thereafter, at S19030, the UE performs a channel sensing operation and determines whether the allocated subband is idle. If the allocated subband is not idle, the UE may refer to Fig.15 The described method senses the subband again. However, if the allocated subband is idle, at S19040, the UE may transmit a PUSCH to the base station through a PRB included in the allocated subband.

[0228] Fig. 20 An example of a resource structure for transmitting a PUSCH (Physical Uplink Shared Channel) according to an embodiment of the present disclosure is illustrated.

[0229] refer to Fig. 20 , among one or more BWPs allocated to the UE, a candidate LBT subband for transmitting the uplink PUSCH may exist in an activated BWP having multiple LBT subbands.

[0230] Specifically, the channel access method in the uplink for performing a BWP-based operation in one carrier for NR-U may consider the following four methods.

[0231] First, the base station configures one or more BWPs for uplink transmission for the UE and activates at least one BWP. When uplink channel access is successful in one or more of the one or more BWPs, the UE can send PUSCH in the one or more BWPs in which the channel access is successful.

[0232] At this time, the base station may inform the UE, through implicit or explicit signaling, of information about one or more activated BWPs among the activated BWPs for which the base station intends the UE to perform uplink transmission.

[0233] Therefore, it is possible to prevent unnecessary channel access from being performed in one or more activated BWPs that are not intended for transmission by the UE. That is, the base station may inform the UE of information about one or more activated BWPs intended for uplink transmission among at least one activated BWP through implicit or explicit signaling.

[0234] For example, the UE may implicitly or explicitly receive information on the activated BWP for performing uplink transmission through DCI transmitted from the base station, thereby recognizing the activated BWP to perform uplink transmission.

[0235] Since the base station notifies the UE of at least one BWP in which uplink transmission will be performed through implicit or explicit signaling, the UE can prevent an unnecessary operation of performing channel access in an activated BWP that is not allocated for uplink transmission.

[0236] Further, the base station may explicitly or implicitly notify the UE whether to perform uplink scheduling in units of LBT subbands included in the activated BWP for uplink transmission of the UE. For example, whether to perform uplink scheduling in units of LBT subbands may be inserted into the DCI and sent to the UE.

[0237] Therefore, even when a plurality of LBT subbands are included in one activated BWP, channel access may be performed only in at least one LBT subband scheduled and allocated for PUSCH transmission among the plurality of LBT subbands.

[0238] The UE may determine whether to send the PUSCH based on whether the channel access is successful.

[0239] In order to explicitly send information about one or more activated BWPs to the UE, the base station can insert the information into the UL grant and send the UL grant, and in order to send information about the LBT subbands scheduled and allocated for PUSCH transmission in an activated BWP to the UE through explicit signaling, the information can be inserted into the UL grant and the UL grant can be sent.

[0240] That is, the base station may send the activated BWP for uplink transmission and the LBT subbands scheduled and allocated for uplink transmission within the BWP to the UE through an indicator (indication).

[0241] For example, the activated BWP for PUSCH transmission and the LBT subband allocated through scheduling for PUSCH transmission may be indicated to the UE through an indicator included in the DCI.

[0242] Further, the activated BWP for PUSCH transmission and the LBT subbands allocated by scheduling for PUSCH transmission may be indicated to the UE through a bitmap scheme, or the base station may indicate each case of allocating LBT subbands to the UE so as to continuously allocate LBT subbands, such as Fig. 20 For example, the base station may send an indicator including a start index and the length of a continuously allocated subband to the UE, and the UE may identify the continuously allocated LBT subband according to the start index and the length of the subband included in the indicator sent from the base station. When the UE performs an LBT operation in the identified subband and channel access is successful, the UE may send a PUSCH.

[0243] Secondly, the base station configures one or more BWPs for uplink transmission to the UE and activates some or all BWPs. When uplink channel access succeeds in one or more BWPs in the activated BWPs, the UE can send PUSCH in one of the one or more BWPs in which the channel access succeeds.

[0244] At this time, the base station can notify the UE of information about one or more activated BWPs among the activated BWPs for which the base station intends the UE to perform uplink transmission through implicit or explicit signaling. Therefore, it is possible to prevent unnecessary channel access from being performed in one or more activated BWPs that are not intended for transmission by the UE. That is, the base station can notify the UE of information about one or more activated BWPs among at least one activated BWP for which uplink transmission is intended through implicit or explicit signaling.

[0245] For example, the UE may implicitly or explicitly receive information on the activated BWP for performing uplink transmission through DCI transmitted from the base station, thereby recognizing the activated BWP to perform uplink transmission.

[0246] Since the base station notifies the UE of a BWP in which uplink transmission will be performed through implicit or explicit signaling, the UE can prevent an unnecessary operation of performing channel access in an activated BWP that is not allocated for uplink transmission.

[0247] Further, the base station may explicitly or implicitly notify the UE whether to perform uplink scheduling in units of LBT subbands included in the activated BWP for uplink transmission of the UE. For example, whether to perform uplink scheduling in units of LBT subbands may be inserted into the DCI and sent to the UE.

[0248] Therefore, even when a plurality of LBT subbands are included in one activated BWP, channel access may be performed only in at least one LBT subband scheduled and allocated for PUSCH transmission among the plurality of LBT subbands.

[0249] The UE may determine whether to send the PUSCH based on whether the channel access is successful.

[0250] The base station may use a UL grant to explicitly send information about one or more activated BWPs to the UE, and may use a UL grant to send information about LBT subbands scheduled and allocated for PUSCH transmission in one activated BWP to the UE through explicit signaling.

[0251] That is, the base station may send the activated BWP for uplink transmission and the LBT subbands scheduled and allocated for uplink transmission within the BWP to the UE through an indicator (indication).

[0252] For example, the activated BWP for PUSCH transmission and the LBT subband allocated through scheduling for PUSCH transmission may be indicated to the UE through an indicator included in the DCI.

[0253] Further, the activated BWP for PUSCH transmission and the LBT subbands allocated by scheduling for PUSCH transmission may be indicated to the UE through a bitmap scheme, or the base station may indicate each case of allocating LBT subbands to the UE so as to continuously allocate LBT subbands, such as Fig. 20 For example, the base station may send an indicator including a start index and a length of a continuously allocated subband to the UE, and the UE may identify the continuously allocated LBT subband according to the start index and the length of the subband included in the indicator sent from the base station. When the UE performs an LBT operation in the identified subband and channel access is successful, the UE may perform uplink transmission.

[0254] Third, the base station configures one or more BWPs for uplink transmission to the UE and activates one of the BWPs. When channel access is successful in all one or more LBT subbands configured and included in an activated BWP, the UE can send a PUSCH to the base station in the corresponding BWP.

[0255] At this time, the base station can notify the UE of information about the activated BWP in which the base station intends the UE to perform uplink transmission through implicit or explicit signaling. Further, the base station can explicitly or implicitly notify the UE whether to perform uplink scheduling in units of LBT subbands included in the activated BWP for uplink transmission of the UE. Therefore, since the UE performs channel access only in the LBT subbands scheduled and allocated for PUSCH transmission among multiple LBT subbands included in an activated BWP, a method for determining whether to send PUSCH can be used based on whether channel access in one or more LBTs allocated to each UE in the BWP is successful.

[0256] In order to explicitly send information about the activated BWP to the UE, the base station can insert the information into the UL grant and send the UL grant, and in order to send information about the LBT subband scheduled and allocated for PUSCH transmission in an activated BWP to the UE through explicit signaling, the information can be inserted into the UL grant and the UL grant can be sent.

[0257] That is, the base station may send the activated BWP for uplink transmission and the LBT subbands scheduled and allocated for uplink transmission within the BWP to the UE through an indicator (indication).

[0258] For example, the activated BWP for PUSCH transmission and the LBT subband allocated through scheduling for PUSCH transmission may be indicated to the UE through an indicator included in the DCI.

[0259] Further, the activated BWP for PUSCH transmission and the LBT subbands allocated by scheduling for PUSCH transmission may be indicated to the UE through a bitmap scheme, or the base station may indicate each case of allocating LBT subbands to the UE so as to continuously allocate LBT subbands, such as Fig. 20 For example, the base station may send an indicator including a start index and a length of a continuously allocated subband to the UE, and the UE may identify the continuously allocated LBT subband according to the start index and the length of the subband included in the indicator sent from the base station. When the UE performs an LBT operation in the identified subband and channel access is successful, the UE may perform uplink transmission.

[0260] -When the bandwidth (BW) of a single BWP is greater than 20 MHz, which is a basic unit for performing LBT operations, it can be determined whether channel access is successful in the activated BWP based on the configuration of the BWP and whether CCA is successful in the LBT subband.

[0261] Specifically, when the BWP includes one or more LBT subbands, and CCA in one or more LBT subbands allocated for PUSCH transmission through UL permission is all successful, it can be determined that the CCA in the BWP for PUSCH transmission has been successful, and the UE can perform PUSCH transmission in the LBT subbands included in the BWP where the CCA is successful.

[0262] However, in the case where CCA is determined to be successful in BWP only when CCA is successful in all LBT subbands, even if channel access is successful in some LBT subbands and the channel is in an idle state, PUSCH transmission may not be achieved if CCA fails in the remaining LBT subbands.

[0263] That is, even if, among the one or more LBT subbands allocated to the UE by the base station through the UL grant for PUSCH transmission in the activated BWP, channel access in some LBT subband units is successful and thus the channel is in an idle state, if channel access in the remaining other LBT subbands included in the activated BWP fails, PUSCH transmission may not be achieved in all activated BWPs. In this case, uplink spectrum efficiency may be reduced, and the bandwidth size in the frequency unit of the BWP may become larger. When multiple LBT subbands are allocated for PUSCH transmission, more multiple channel accesses are required to succeed in channels in units of 20 MHz as LBT subband units, thereby possibly reducing the success probability of channel access in the corresponding activated BWP and reducing the transmission probability in the activated BWP.

[0264] However, when there is no separate mechanism to determine (or identify) which LBT subband among the LBT subbands allocated by the base station to the UE for PUSCH transmission successfully performs uplink channel access, the base station can only determine (or identify) whether the UE successfully performs LBT for PUSCH transmission by detecting in the LBT subband corresponding to the resources allocated by the base station to the UE for PUSCH transmission.

[0265] However, the base station cannot determine or identify whether DTX is performed in the case where LBT succeeds and then PUSCH transmission is performed and in the case where LBT fails and PUSCH transmission is not performed. Therefore, when the UE sends PUSCH, the base station can detect the front-loaded UL (uplink) DMRS (dedicated demodulation reference signal), thereby identifying (or determining) the LBT subband in which the UE successfully performs channel access among the LBT subbands allocated for PUSCH transmission, and also determine whether the UE performs transmission after LBT succeeds and whether DTX is performed in the case where LBT fails and PUSCH transmission is not performed.

[0266] - Further, when UL transmission is performed through the configured grant, the base station cannot send an indicator for indicating the LBT subband within the BWP to the UE through the UL grant. Therefore, in this case, when the UE successfully performs uplink channel access in an LBT subband among the LBT subbands in the activated BWP configured in the UE in the time resource configured through RRC, the UE can be configured to perform UL transmission according to the configured grant through the corresponding LBT subband.

[0267] However, in order to perform transmission in LBT subband units in the case of performing UL transmission through the configured grant, frequency resources should be configured in units of LBT subbands, and channel access should succeed in at least one of one or more LBT subbands included in one activated BWP.

[0268] At this time, when channel access succeeds only in the LBT subband allocated to UL transmission by the UL grant, UL transmission according to the UL grant is prioritized, so UL transmission according to the configured grant may not be performed. The base station may determine whether to send the configured grant by performing detection not only in the LBT subband allocated to UL transmission according to the UL grant, but also in the LBT subband to which UL transmission according to the UL grant is not allocated within the activated BWP, by detecting the frontload UL DM-RS.

[0269] Fourth, the base station configures one or more BWPs for uplink transmission to the UE and activates one of the BWPs. When channel access is successful in all or part of the LBT subbands configured and included in an activated BWP, the UE can send PUSCH to the base station in the corresponding BWP.

[0270] At this time, the base station can notify the UE of information about the activated BWP in which the base station intends the UE to perform uplink transmission through implicit or explicit signaling. Further, the base station can explicitly or implicitly notify the UE whether to perform uplink scheduling in units of LBT subbands included in the activated BWP for uplink transmission of the UE. Therefore, since the UE performs channel access only in the LBT subband scheduled and allocated for PUSCH transmission among multiple LBT subbands included in an activated BWP, a method of determining whether to send PUSCH based on whether channel access in one or more LBTs allocated to each UE in the BWP is successful can be used.

[0271] In order to explicitly send information about an activated BWP to the UE, the base station can insert the information into the UL grant and send the UL grant, and in order to send information about the LBT subband scheduled and allocated for PUSCH transmission in an activated BWP to the UE through explicit signaling, the information can be inserted into the UL grant and the UL grant can be sent.

[0272] That is, the base station may send the activated BWP for uplink transmission and the subbands scheduled and allocated for uplink transmission within the BWP to the UE through an indicator (indication).

[0273] For example, the activated BWP for PUSCH transmission and the LBT subband allocated through scheduling for PUSCH transmission may be indicated to the UE through an indicator included in the DCI.

[0274] Further, the activated BWP for PUSCH transmission and the LBT subbands allocated by scheduling for PUSCH transmission may be indicated to the UE through a bitmap scheme, or the base station may indicate each case of allocating LBT subbands to the UE so as to continuously allocate LBT subbands, such as Fig. 20 For example, the base station may send an indicator including a start index and a length of a continuously allocated subband to the UE, and the UE may identify the continuously allocated LBT subband according to the start index and the length of the subband included in the indicator sent from the base station. When the UE performs an LBT operation in the identified subband and channel access is successful, the UE may perform uplink transmission.

[0275] -When the bandwidth (BW) of a single BWP is greater than 20 MHz, which is a basic unit for performing LBT operations, it can be determined whether channel access is successful in the activated BWP based on the configuration of the BWP and whether CCA is successful in the LBT subband.

[0276] Specifically, when the BWP includes one or more LBT subbands, and CCA is fully or partially successful in one or more LBT subbands allocated for PUSCH transmission through UL grant, it can be determined that the CCA in the BWP for PUSCH transmission has been successful, and the UE can perform PUSCH transmission in the LBT subbands included in the BWP where the CCA is successful.

[0277] Further, when in an activated BWP, channel access in some LBT subband units is successful in one or more LBT subbands allocated for PUSCH transmission to the UE by the base station through UL permission, so that the channel is in an idle state, PUSCH transmission can be performed in some LBT subbands in which channel access allocated for PUSCH transmission has been successful.

[0278] However, the UE may fail to access the channel in some LBT subbands allocated for PUSCH transmission, and thus may not be able to perform PUSCH transmission therein. Accordingly, the base station may configure the resources to be allocated for PUSCH transmission in units of LBT subbands, so that PUSCH is sent from the UE only in some LBT subbands, and even if PUSCH is sent only in some LBT subbands, the base station can receive PUSCH sent in the corresponding LBT subband.

[0279] However, when there is no separate mechanism for determining which LBT subband among the LBT subbands for PUSCH transmission allocated by the base station to the UE is successful in uplink channel access, the base station can determine whether the LBT for the UE's PUSCH transmission is successful simply by performing detection on the LBT subband corresponding to the resources for PUSCH transmission allocated by the base station to the UE.

[0280] At this time, the base station cannot determine or identify whether DTX is performed in the case where LBT succeeds and then PUSCH transmission is performed and in the case where LBT fails and PUSCH transmission is not performed. Therefore, when the UE sends PUSCH, the base station can detect the front-loaded UL (uplink) DMRS (dedicated demodulation reference signal), thereby identifying (or determining) the LBT subband in which the UE successfully performs channel access in the LBT subband allocated for PUSCH transmission, and also determine whether the UE performs DTX in the case where LBT succeeds and then transmission is performed and in the case where LBT fails and PUSCH transmission is not performed.

[0281] - Further, when UL transmission is performed through the configured grant, the base station cannot send an indicator for indicating the LBT subband within the BWP to the UE through the UL grant. Therefore, in this case, when the UE successfully performs uplink channel access in an LBT subband among the LBT subbands in the activated BWP configured in the UE in the time resource configured through RRC, the UE can be configured to perform UL transmission according to the configured grant through the corresponding LBT subband.

[0282] However, in order to perform transmission in LBT subband units in the case of performing UL transmission through the configured grant, frequency resources should be configured in units of LBT subbands, and channel access should succeed in at least one of one or more LBT subbands included in one activated BWP.

[0283] At this time, when channel access succeeds only in the LBT subband allocated to UL transmission by the UL grant, UL transmission according to the UL grant is prioritized, so UL transmission according to the configured grant may not be performed. The base station may determine whether to send the configured grant by performing detection not only in the LBT subband allocated to UL transmission according to the UL grant, but also in the LBT subband to which UL transmission according to the UL grant is not allocated within the activated BWP, by detecting the frontload UL DM-RS.

[0284] <Resource Allocation Method When One or More LBT Subbands Are Included in One BWP>

[0285] Fig.21 An example of an interleaving structure for allocating uplink resources in LTE-LAA is illustrated.

[0286] refer to Fig.21 In NR-U operation, a BWP may include one or more LBT subbands (or LBT units, subbands) to perform LBT operation for channel access.

[0287] Specifically, in order to use the unlicensed band in case of uplink transmission, the OCBB (Occupied Channel Bandwidth) requirement defined and required in the corresponding unlicensed band should be met.

[0288] For example, uplink transmission has a condition that it should meet 80% of the nominal channel bandwidth. In order to meet this condition, Fig.21 As shown, in LTE-LAA, PRBs can be configured to be uniformly extended to the entire bandwidth with the same PRB spacing.

[0289] For example, 10 different interleaving indices may be configured using 10 interleaving structures at 10 PRBs in the system bandwidth, and the respective PRBs may be configured to perform allocation over the entire channel bandwidth for each allocated index.

[0290] This PRB structure may be referred to as an interleaved structure, and the interleaved structure may be used to meet OCB requirements in NR-U operations using unlicensed bands based on NR.

[0291] Therefore, when the requirements are not met, uplink or downlink data transmission may not be performed using the unlicensed frequency band.

[0292] Therefore, the present disclosure proposes a method for transmitting and receiving data through an unlicensed band while satisfying NR-based OCB requirements.

[0293] That is, when one BWP includes one or more LBT subbands (or LBT units) in an NR-U based operation of transmitting uplink data or downlink data using an NR based unlicensed band, a method of allocating resources for uplink data transmission is proposed.

[0294] Fig. 22 An example of candidate LBT subbands and their interleaving structure for uplink PUSCH transmission in a bandwidth part (BWP) with activation of multiple LBT (Listen Before Talk) subbands in one or more BWPs is illustrated.

[0295] refer to Fig. 22 In order to satisfy the OCB as a requirement of the unlicensed band to use the unlicensed band, the base station may allocate LBT subbands and PRBs included in the activated BWP at regular intervals and notify the UE of the locations of the allocated LBT subbands and PRBs.

[0296] Specifically, Fig. 20 As shown, the size of the BWP configured for each UE may be different, and the PRBs allocated to each UE may be allocated within the activated BWP at regular intervals.

[0297] For example, Fig. 22 As shown, the number of LBT subbands included in one BWP may be defined as N, and the interval between different RBs having an interleaving structure within an LBT subband in the frequency domain in one interleaving structure may be defined as M. At this time, depending on different subcarrier spacing (SCS) values, M may be the same or different. For example, when different SCS values ​​15kHz and 30kHz are used, for 15kHz, 10 or 11 may be used as M, and for 30kHz, 5 may be used as M.

[0298] First, in the case of uplink data transmission, the UE may receive resource allocation information of frequency resources for uplink data transmission from the base station. In this case, the base station may allocate uplink frequency resources to the UE and allocate resources for uplink transmission by using an interleaving structure only in the continuously allocated LBT subbands. Alternatively, the base station may allocate resources for uplink transmission to the UE by using an interleaving structure in each LBT subband in the allocated LBT subbands, regardless of whether the LBT subbands are continuously allocated or non-continuously allocated.

[0299] When one BWP includes one or more LBT subbands for NR-U operation, and due to the flexibility of scheduling of the base station in the uplink transmission of the UE and the failure of LBT for channel access in a specific LBT subband for the UE, both the non-contiguous LBT subband allocation scheme and the continuous LBT subband allocation scheme can be used. In this case, the base station can notify the UE of the allocation information of the non-contiguous LBT subband or the allocation information of the continuous LBT subband for uplink transmission.

[0300] At this time, the base station may send an indicator (indication) indicating the allocated LBT subband and the interleaving structure of the LBT subband to the UE, and the LBT subband and the interleaving structure may be encoded together or separately and sent to the UE.

[0301] The bitmap scheme or the RIV scheme may be used as an indicator for notifying the UE of the LBT subband and the interleaving structure. For example, the base station may notify the detailed position of each LBT subband in the LBT subband through the indicator, and use the bitmap scheme to notify the interleaving structure in the LBT subband through each bit. Alternatively, the base station may notify the UE of the starting position and length of the LBT subband through the indicator, and notify the UE of the starting interleaving index and length through the interleaving structure.

[0302] That is, the base station can notify the UE of the positions of the consecutively allocated LBT subbands and the indexes (or positions) of the PRBs with an interleaved structure through a bitmap scheme or a RIV scheme.

[0303] Specifically, the base station may allocate continuous LBT subbands allocated to perform LBT operation to allow the UE to perform uplink transmission in the unlicensed band and allocate PRBs in each LTE subband to have an interleaving structure at regular intervals.

[0304] The base station may encode information related to the position of the consecutively allocated LBT subbands and information related to the PRB with an interleaved structure (e.g., index, etc.) together or separately, and send it to the UE. At this time, the information encoded together or separately may be sent through DCI. At this time, the DCI may further include an indicator indicating whether the PRB of the BWP has an interleaved structure.

[0305] The base station can send information related to the location of consecutively allocated LBT subbands and information related to PRBs with an interleaved structure (e.g., indexes, etc.) to the UE through DCI by using a bitmap scheme or a RIV scheme, and can selectively use the RIV or bitmap scheme according to specific conditions.

[0306] For example, when the specific condition is the subcarrier spacing, the bitmap scheme or the RIV scheme may be selectively used according to the value of the subcarrier spacing.

[0307] For example, when the subcarrier spacing is 15 kHz, the base station can encode the positions of the consecutively allocated LBT subbands and the indexes of the PRBs with an interleaved structure together or separately through the RIV scheme, and send them to the UE through DCI.

[0308] That is, the base station can encode the starting position of the continuously allocated LBT subband and the length (or position) of the continuously allocated LBT subband, and send it to the UE through DCI. In addition, the base station can encode the information indicating the starting index of the PRB with an interleaved structure and the length index of the continuously allocated PRB separately from the information related to the position of the continuously allocated LBT subband, and insert it into the DCI, or can encode the information together with the information related to the position of the continuously allocated LBT subband, insert it into the DCI, and send the DCI to the UE.

[0309] Alternatively, when the subcarrier spacing is 15 kHz, the base station may encode the positions of the consecutively allocated LBT subbands and the indexes of the PRBs having an interleaved structure together or separately through a bitmap scheme, and send them to the UE through DCI.

[0310] That is, the base station can encode the starting position of the continuously allocated LBT subband and the length (or position) of the continuously allocated LBT subband, and send it to the UE through DCI. In addition, the base station can encode the information indicating the starting index of the PRB with an interleaved structure and the length index of the continuously allocated PRB separately from the information related to the position of the continuously allocated LBT subband, and insert it into the DCI, or can encode the information together with the information related to the position of the continuously allocated LBT subband, insert it into the DCI, and send the DCI to the UE.

[0311] Alternatively, when the subcarrier spacing is 30kHz, the base station can indicate the starting position and length of the continuously allocated LBT subbands through the RIV scheme, and can encode the indexes of the PRBs with an interleaved structure individually or together through a bitmap scheme to have full flexibility, and send the encoded information to the UE through DCI.

[0312] That is, the base station can encode the starting position and length of the continuously allocated LBT subband through the RIV scheme, insert it into the DCI, and send the DCI to the UE. In addition, the base station can indicate the index of the PRB with an interleaved structure allocated to the UE through a specific bit. The specific bit of the index of the PRB with an interleaved structure can be encoded separately from the position information of the LBT subband encoded by the RIV scheme, inserted into the DCI, and sent to the UE.

[0313] Alternatively, when the subcarrier spacing is 30kHz, the base station can indicate the starting position and length of the continuously allocated LBT subbands through the RIV scheme, and can encode the indexes of PRBs with an interleaved structure separately or together through the RIV scheme, and send the encoded information to the UE through DCI.

[0314] That is, the base station can encode the starting position and length of the continuously allocated LBT subband through the RIV scheme, insert it into the DCI, and send the DCI to the UE. In addition, the base station can indicate the index of the PRB with an interleaved structure allocated to the UE through the RIV, and encode a specific bit separately from the position information of the LBT subband encoded by the RIV scheme, insert it into the DCI, and send the DCI to the UE.

[0315] Alternatively, when the subcarrier spacing is 30 kHz, the base station may encode the positions of the consecutively allocated LBT subbands and the indexes of the PRBs having an interleaved structure together or separately through a bitmap scheme and send them to the UE through DCI.

[0316] That is, the base station can indicate the position of the LBT subbands allocated continuously using bits of a specific size through a bitmap scheme, and can insert the bits of the specific size into the DCI and send it to the UE. In addition, the base station can indicate the index of the PRB with an interleaved structure allocated to the UE through a specific bit, and can encode the specific bit separately, insert it into the DCI, and send the DCI to the UE.

[0317] Alternatively, the position of the LBT subband and the index of the PRB having an interleaved structure may be mapped to each other and defined as a bit value, and each mapped bit value may be inserted into the DCI and sent to the UE.

[0318] When receiving a DCI including information related to an LBT subband and a PRB having an interleaved structure, the UE can identify the LBT subband to perform an LBT operation, and after performing the LBT operation in the identified LBT subband, can send uplink data to the base station in the PRB included in the LBT subband in which the LBT operation has been successful.

[0319] When the location of the LBT subband is notified by a bitmap scheme, the UE can be notified of the number of N allocated LBT subbands and the allocated LBT subbands using a bitmap of length N in the scheduling information through DCI. In addition, M(M+1) / 2 states may be required to allocate interleaving indices associated with one or more consecutive PRBs in the interleaving structure of each subband. In order to indicate the state for allocating interleaving indices by bits, log2{M(M+1) / 2} bits or more may be required. Therefore, floor(log2{M(M+1) / 2}) or ceiling(log2{M(M+1) / 2}) bits may be required to indicate the interleaving index of the PRB.

[0320] When non-contiguous LBT subband allocations are allocated, N bits + ceiling (log2{M(M+1) / 2}) (or floor (log2{M(M+1) / 2})) bits may be required to allocate resources for uplink transmission.

[0321] For NR-U operation, one BWP may include one or more LBT subbands, and the base station may allocate resources for uplink transmission based on the interleaving structure in consecutive LBT subbands so that the UE receives uplink frequency resources from the base station and the UE may receive resources through it.

[0322] When uplink frequency resources are allocated only through consecutive LBT subbands, the base station may indicate the allocated resources to the UE through the method for the above-mentioned scheme allowing allocation of resources of non-consecutive subbands.

[0323] That is, when the position of the LBT subband is notified through a bitmap scheme, the UE can be notified of the number of N allocated LBT subbands and the allocated LBT subbands using a bitmap of length N in the scheduling information through DCI. In addition, M(M+1) / 2 states may be required to allocate interleaving indices associated with one or more consecutive PRBs in the interleaving structure of each subband. In order to indicate the state for allocating interleaving indices by bits, log2{M(M+1) / 2} bits or more may be required. Therefore, floor(log2{M(M+1) / 2}) or ceiling(log2{M(M+1) / 2}) bits may be required to indicate the interleaving index of the PRB.

[0324] When an interleaving structure is used only in consecutive LBT subbands to allocate resources for uplink transmission, if the indexes of the interleaving structure of the LBT subbands and PRBs are individually indicated to the UE, the number of LBT subbands included in one BWP is larger and the value of M in the interleaving structure of the subbands is larger, so the number of states for uplink resource allocation may become larger.

[0325] Therefore, since the number of bits of the RA (resource allocation) field used to allocate uplink resources increases, if resources for uplink transmission are allocated only in consecutive LBT subbands using an interleaving structure and scheduled to the UE, the allocation information and index of the allocated LBT subbands according to the interleaving structure can be encoded together and scheduled to the UE through an indicator.

[0326] The UE can identify the location of one or more LBT subbands and the resource information of the PRB in the interleaving structure within the corresponding LBT subband by the value of an RA field (for resource allocation information) included in the scheduling information (or DCI) sent from the base station.

[0327] The UE may perform LBT for channel access for each of the identified LBT subbands, and when channel access has succeeded according to the LBT operation, perform uplink transmission to the base station through corresponding resources. Hereinafter, a detailed method is described.

[0328] (Method 1)

[0329] like Fig. 20 and Fig. 22 As shown, when only consecutive LBT subbands are allocated, if the number of LBT subbands is N, the number of combinations of LBT subbands that can be consecutively allocated can be calculated by the following Equation 1.

[0330] [Equation 1]

[0331]

[0332] In addition, the number of states for allocating interleaving indices for one or more consecutive PRBs in an interleaving structure may be M(M+1) / 2. When M(M+1) / 2 states are configured, if the PRB indices for one or more consecutive LBT subbands and one or more consecutive interleaving structures are encoded together and indicated to the UE, the number of states for the PRBs for one or more consecutive LBT subbands and one or more consecutive interleaving structures may be configured as shown in Equation 2 below.

[0333] [Equation 2]

[0334]

[0335] exist Fig. 22 In the embodiment, since the number of combinations of LBT subbands that can be continuously allocated is 10 when the value of N is 4, and the value of M is 10 when the subcarrier spacing is 15 kHz, the total number of states for one or more continuous LBT subbands and one or more continuous interleaving structures can be 550.

[0336] In this case, compared with the case where the position of the allocated LBT subband is allocated separately from the index of the PRB allocated in the interleaved structure through a bitmap, that is, 9 reserved states are reserved in 4 bits + 6 bits (55 states) = 10 bits, so only 9 states can be allocated in the interleaved structure for the additional predetermined mapping method, the number of bits of the RA field used for resource allocation can be the same as 10 bits. However, compared with the separate encoding method, the simultaneous encoding method based on the bit size of the same RA field may have 474 remaining states. That is, compared with the separate encoding method, the simultaneous encoding method can further map 474 states.

[0337] Therefore, the method in which the base station allocates resources according to a preset mapping scheme can have the effect of increasing the flexibility of resource allocation. In addition, compared with the method of encoding the LBT subband separately and indicating the LBT subband to the UE, the method of encoding one or more consecutive LBT subbands (the number of LBT subbands is greater than or equal to 5) and PRBs with one or more consecutive interleaving structures together and mapping them can reduce the number of bits used for resource allocation.

[0338] [Table 4]

[0339]

[0340] refer to Fig. 20 , one or more consecutive LBT subbands and consecutive interleaving structures for cases 1) to 10) may be sequentially mapped in ascending order and calculated and / or configured, and the calculated and / or configured information may be sent to the UE through an indicator. At this time, the indicator may be sent while being inserted into DCI, which is downlink control information for sending uplink scheduling information.

[0341] For example, in Fig. 20 In the case of, one or more consecutive LBT subbands and PRB indexes with one or more consecutive interleaving structures can be sequentially mapped in the order of case 1) →→ case 2) →…→ case 10) and sent to the UE through an indicator.

[0342] Alternatively, the information may be mapped sequentially in ascending order by giving priority to the number of LBT subbands, and calculated and / or configured, and the calculated and / or configured information may be sent to the UE through an indicator. At this time, the indicator may be sent while being inserted into the DCI, which is downlink control information for sending uplink scheduling information.

[0343] For example, in Fig. 20In this case, the information can be mapped in ascending order of case 1) -> case 5) -> case 8) -> case 10) -> case 2) -> case 6) -> case 9) -> case 3) -> case 7) -> case 4) by giving priority to the number of LBT subbands and sent to the UE through an indicator.

[0344] The base station can calculate corresponding information based on the value of M determined by the number of LBT subbands included in the BWP and the subcarrier spacing, allocate resources for uplink transmission to the UE, and send DCI including resource allocation information related to the allocated resources to the UE.

[0345] The UE may receive the DCI including resource allocation information and perform uplink transmission using one or more LBT subbands allocated to the UE and PRBs having one or more consecutive interleaving structures.

[0346] (Method 2)

[0347] The RIV scheme can be used to allocate resources having one or more interleaved structures according to a scheme used in LTE-AAA for each LBT subband in one or more LBT subbands, and a mapping mode that is a predetermined resource mapping mode used in LTE-AAA can be used for RIV having a value greater than or equal to M(M+1) / 2.

[0348] For example, the resource mapping pattern shown in Table 5 below may be used.

[0349] [Table 5]

[0350] RIV-N(N+1) / 2 <![CDATA[RB START ]]> l 0 0 {0,5} 1 0 {0,1,5,6} 2 1 {0,5} 3 1 {0,1,2,3,5,6,7,8} 4 2 {0,5} 5 2 {0,1,2,5,6,7} 6 3 {0,5} 7 4 {0,5}

[0351] In Table 5, RB START represents a start index of consecutively allocated RBs having an interleaving structure, and l indicates an index of consecutively allocated RBs having an interleaving structure.

[0352] M corresponding to an interval between different RBs in the frequency domain of one interleaving structure may be described as N=M, but is not limited thereto and may have various values.

[0353] In the following, N may indicate the interval between different RBs in the frequency domain of an interleaving structure and does not mean Figures 19 to 22 That is, when the uplink resource allocation type 3 used in LTE-AAA is also applied to NR-U, a predetermined resource mapping method as shown in [Table 5] can be used based on the index of a PRB having a continuous interleaving structure (for example, 10 interleaving structures with a subcarrier spacing of 15 kHz in an LBT subband unit with a bandwidth of 20 MHz).

[0354] Alternatively, in addition to the M(M+1) / 2 states for indicating the total continuous interleaving structure, X (eg, X is 8 when M=10 in the case of SCS of 15 kHz) states may be used.

[0355] The number of Xs used for the predetermined resource mapping additionally configured according to the subcarrier spacing may have the same value or different values. Method 2 proposes a method of encoding and indicating the LBT subband while also using this method.

[0356] For example, Equation 1 is applied, but Equation 2 may be modified into the following Equation 3, and Equation 3 may be applied.

[0357] [Equation 3]

[0358]

[0359] refer to Fig. 20 In method 2, as in method 1, one or more consecutive LBT subbands and consecutive interleaving structures for cases 1) to 10) may be sequentially mapped in ascending order and calculated and / or configured, and the calculated and / or configured information may be sent to the UE through an indicator. At this time, the indicator may be included in the DCI as downlink control information and sent.

[0360] For example, in Fig. 20 In the case of, one or more consecutive LBT subbands and PRB indexes with one or more consecutive interleaving structures can be sequentially mapped in the order of case 1) →→ case 2) →…→ case 10) and sent to the UE through an indicator.

[0361] Alternatively, the information may be mapped sequentially in ascending order by giving priority to the number of LBT subbands, and calculated and / or configured, and the calculated and / or configured information may be sent to the UE through an indicator. At this time, the indicator may be included in the DCI as downlink control information and sent.

[0362] For example, in Fig. 20 In this case, the information can be mapped in ascending order of case 1) -> case 5) -> case 8) -> case 10) -> case 2) -> case 6) -> case 9) -> case 3) -> case 7) -> case 4) by giving priority to the number of LBT subbands and sent to the UE through an indicator.

[0363] In this case, compared with method 1), the states included in the case of method 2 may include X states in addition to M(M+1) / 2 states, for indicating the total continuous interleaving structure to the UE.

[0364] Uplink resource allocation type 3

[0365] The uplink resource allocation type 3 applied to the SCell of LAA can be applied to NR-U. The resource allocation information for uplink resource allocation type 3 can indicate the resource block set RB allocated to the scheduled UE. START +l+i·N. The value N is shown in equation 4:

[0366] [Equation 4]

[0367]

[0368] When the number of uplink RBs When 100, the resource allocation field of the scheduling grant may include RIV. is 100 and 0≤RIV<N(N+1) / 2, l=0, 1, ...L-1, and RIV may correspond to the starting resource block (RB START ) and L (L ≥ 1). RIV can be defined as shown in the following equation 5.

[0369] [Equation 5]

[0370] if but

[0371] RIV=N(L-1)+RB START

[0372] otherwise

[0373] RIV=N(N-L+1)+(N-1-RB START )

[0374] when When RIV is 100 and RIV ≥ N(N+1) / 2, RIV may correspond to the starting resource block of RB (RB START ) and Table 4.

[0375] In reference Figures 19 to 22 In the method described, when DFT-spread OFDM is excluded from the uplink transmission scheme, it can be achieved by referring to Figures 19 to 22 The described method indexes and indicates to the UE the indices allocated at intervals of 7 RBs and having an interleaved structure.

[0376] However, when the UE is configured to use DFT-spread OFDM, the index of the RBs allocated at intervals of 7 RBs and having an interleaving structure may be configured as a reserved index.

[0377] When a BWP includes one or more LBT subbands, the present disclosure has the effect of reducing the number of states for indicating resource allocation information related to resources allocated for PUSCH transmission according to an increase in the number of LBT subbands or an increase in the interval between different RBs in the frequency domain of the interleaved structure (i.e., the positions of one or more LBT subbands and resource allocation information of PRBs allocated within the corresponding LBT subbands in an interleaved structure), compared to an indicator indicating LBT subbands independently allocated for PUSCH transmission and a method of configuring and allocating PRBs in an interleaved structure.

[0378] Fig.23 is a flowchart illustrating an example of a method in which a UE receives resources of an unlicensed band from a base station and transmits uplink data according to another embodiment of the present disclosure.

[0379] refer to Fig.23 The UE can receive allocation information indicating continuous LBT subbands and allocation information indicating PRBs with an interleaved structure from the base station through downlink control information, so as to send uplink data through the unlicensed frequency band, and send uplink data to the base station through the allocated LBT subbands and PRBs with an interleaved structure.

[0380] Specifically, in S23010, the UE may receive downlink control information (DCI) for allocating at least one subband for transmitting a PUSCH (Physical Uplink Shared Channel) and a plurality of resource blocks included in each of the at least one subband from the base station.

[0381] The UE may receive RRC configuration information including parameters for receiving DCI before receiving DCI from the base station.

[0382] Can be like in reference Figure 20 to Figure 22 In the method described in the present invention, a plurality of resource blocks are allocated within the system bandwidth as described in the present invention. For example, a plurality of resource blocks may be referred to as PRBs and may be allocated in an interleaved structure in which allocation is performed at regular intervals to occupy a predetermined portion (e.g., 80%) of the system bandwidth. A plurality of PRBs having an interleaved structure may be included in the allocated LBT subband.

[0383] At this time, the at least one allocated subband may be included in a bandwidth part (BWP) activated based on the first resource allocation information, and at least one subband allocated for uplink transmission in one BWP may be continuously allocated.

[0384] Furthermore, the plurality of allocated resource blocks may be included in an interleaving structure in which the resource blocks are continuously allocated at regular intervals in the activated BWP based on the second resource allocation information.

[0385] The DCI may include first resource allocation information associated with the location of at least one allocated subband and second resource allocation information associated with the locations of a plurality of allocated resource blocks, as described in reference Figure 20 to Figure 22 described in the method.

[0386] For example, the DCI may include second resource allocation information related to the positions of multiple resource blocks with an interleaved structure and first resource allocation information related to the positions of the allocated LBT subbands, and the second resource allocation information of the multiple resource blocks with an interleaved structure and the first resource allocation information related to the positions of the allocated LBT subbands may be encoded separately or together and included in the DCI.

[0387] At this point, you can refer to Figure 20 to Figure 22 The described bitmap scheme or RIV scheme transmits second resource allocation information of a plurality of resource blocks having an interleaved structure and first resource allocation information related to the position of the allocated LBT subband to the UE through an indicator.

[0388] For example, the second resource allocation information of a plurality of resource blocks having an interleaved structure and the first resource allocation information related to the position of the allocated LBT subband may be indicated according to a specific condition through a bitmap scheme or a RIV scheme.

[0389] At this time, in the example of specific conditions, with the help of a bitmap scheme or a RIV scheme, second resource allocation information of multiple resource blocks with an interleaved structure and first resource allocation information related to the position of the allocated LBT subband can be sent to the UE through an indicator according to the value of the subcarrier spacing.

[0390] For example, when the subcarrier spacing is 15 kHz, according to the RIV scheme, second resource allocation information of a plurality of resource blocks having an interleaved structure and first resource allocation information of the allocated LBT subband may be included in the DCI.

[0391] That is, the starting indexes of multiple resource blocks with an interleaved structure, the values ​​related to the indices of consecutively allocated resource blocks, the starting indexes of consecutively allocated LBT subbands, and the indices of consecutively allocated LBT subbands may be encoded separately or together and included in the DCI.

[0392] In addition, when the subcarrier spacing is 15kHz, the second resource allocation information of multiple resource blocks with an interleaved structure and the first resource allocation information of the allocated LBT subband can be sent to the UE through an indicator according to a bitmap scheme.

[0393] That is, the detailed positions of a plurality of resource blocks having an interleaved structure and consecutively allocated LBT subbands may be encoded individually or together by a value of each bit having a specific size and included in the DCI.

[0394] Alternatively, when the subcarrier spacing is 30kHz, first resource allocation information of consecutively allocated LBT subbands may be included in the DCI according to the RIV scheme, and second resource allocation information of multiple resource blocks with an interleaved structure may be included in the DCI through an indicator and sent to the UE.

[0395] That is, the starting indexes of multiple resource blocks with an interleaved structure, the values ​​related to the indices of consecutively allocated resource blocks, the starting indexes of consecutively allocated LBT subbands, and the indices of consecutively allocated LBT subbands may be encoded separately or together and included in the DCI.

[0396] Alternatively, when the subcarrier spacing is 30 kHz, second resource allocation information of a plurality of resource blocks having an interleaved structure and first resource allocation information of the allocated LBT subband may be sent to the UE through an indicator according to a bitmap scheme.

[0397] That is, the detailed positions of a plurality of resource blocks having an interleaved structure and consecutively allocated LBT subbands may be encoded individually or together by a value of each bit having a specific size and included in the DCI.

[0398] When the detailed positions of multiple resource blocks with an interleaved structure and continuously allocated LBT subbands are encoded together and sent to the UE through an indicator, the information can be mapped to an indicator indicating the indexes of multiple resource blocks with an interleaved structure and continuously allocated LBT subbands, and an indicator indicating each mapping state can be included in the DCI and sent to the UE.

[0399] Thereafter, the UE may perform channel access as LBT operation in consecutive LBT subbands indicated by the DCI.

[0400] When the UE successfully accesses the channel in the allocated continuous LBT subband, in S23020, the UE can send PUSCH to the base station via first resource allocation information indicating the continuous LBT subband via DCI and second resource allocation information of multiple resource blocks allocated in an interleaved structure within the LBT subband.

[0401] When the UE fails to access the channel in the allocated continuous LBT subband, the UE may not send the PUSCH to the base station. Fig.24 is a flowchart illustrating an example of a method in which a base station allocates resources of an unlicensed band to a UE and receives uplink data according to another embodiment of the present disclosure.

[0402] refer to Fig.24 The base station can indicate allocation information indicating continuous LBT subbands and allocation information indicating PRBs with an interleaved structure to the UE through downlink control information, so as to receive uplink data through the unlicensed frequency band, and receive uplink data from the UE through the allocated LBT subbands and PRBs with an interleaved structure.

[0403] Specifically, in S24010, the base station may transmit, to the UE, downlink control information (DCI) for allocating at least one subband for transmitting a PUSCH (Physical Uplink Shared Channel) and a plurality of resource blocks included in each of the at least one subband.

[0404] The base station may transmit RRC configuration information including parameters for receiving DCI to the UE before receiving the DCI.

[0405] Can be like in reference Figure 20 to Figure 22 In the method described in the present invention, a plurality of resource blocks are allocated within the system bandwidth as described in the present invention. For example, a plurality of resource blocks may be referred to as PRBs and may be allocated in an interleaved structure in which allocation is performed at regular intervals to occupy a predetermined portion (e.g., 80%) of the system bandwidth. A plurality of PRBs having an interleaved structure may be included in the allocated LBT subband.

[0406] At this time, the at least one allocated subband may be included in a bandwidth part (BWP) activated based on the first resource allocation information, and at least one subband allocated for uplink transmission in one BWP may be continuously allocated.

[0407] In addition, the plurality of allocated resource blocks may be included in an interleaved structure in which the resource blocks are continuously allocated at regular intervals in the activated BWP based on the second resource allocation information. The DCI may include first resource allocation information associated with the location of at least one allocated subband and second resource allocation information associated with the locations of the plurality of allocated resource blocks, as described in reference Figure 20 to Figure 22 described in the method.

[0408] For example, the DCI may include second resource allocation information related to the positions of multiple resource blocks with an interleaved structure and first resource allocation information related to the positions of the allocated LBT subbands, and the second resource allocation information of the multiple resource blocks with an interleaved structure and the first resource allocation information related to the positions of the allocated LBT subbands may be encoded separately or together and included in the DCI.

[0409] At this point, you can refer to Figure 20 to Figure 22The described bitmap scheme or RIV scheme transmits second resource allocation information of a plurality of resource blocks having an interleaved structure and first resource allocation information related to the position of the allocated LBT subband to the UE through an indicator.

[0410] For example, the second resource allocation information of a plurality of resource blocks having an interleaved structure and the first resource allocation information related to the position of the allocated LBT subband may be indicated according to a specific condition through a bitmap scheme or a RIV scheme.

[0411] At this time, in the example of specific conditions, with the help of a bitmap scheme or a RIV scheme, second resource allocation information of multiple resource blocks with an interleaved structure and first resource allocation information related to the position of the allocated LBT subband can be sent to the UE through an indicator according to the value of the subcarrier spacing.

[0412] For example, when the subcarrier spacing is 15 kHz, according to the RIV scheme, second resource allocation information of a plurality of resource blocks having an interleaved structure and first resource allocation information of the allocated LBT subband may be included in the DCI.

[0413] That is, the starting indexes of multiple resource blocks with an interleaved structure, the values ​​related to the indices of consecutively allocated resource blocks, the starting indexes of consecutively allocated LBT subbands, and the indices of consecutively allocated LBT subbands may be encoded separately or together and included in the DCI.

[0414] In addition, when the subcarrier spacing is 15 kHz, second resource allocation information of a plurality of resource blocks having an interleaved structure and first resource allocation information of the allocated LBT subband are sent to the UE through an indicator.

[0415] That is, the detailed positions of a plurality of resource blocks having an interleaved structure and consecutively allocated LBT subbands may be encoded individually or together by a value of each bit having a specific size and included in the DCI.

[0416] Alternatively, when the subcarrier spacing is 30kHz, first resource allocation information of consecutively allocated LBT subbands may be included in the DCI according to the RIV scheme, and second resource allocation information of multiple resource blocks with an interleaved structure may be included in the DCI through an indicator and sent to the UE.

[0417] That is, the starting indexes of multiple resource blocks with an interleaved structure, the values ​​related to the indices of consecutively allocated resource blocks, the starting indexes of consecutively allocated LBT subbands, and the indices of consecutively allocated LBT subbands may be encoded separately or together and included in the DCI.

[0418] Alternatively, when the subcarrier spacing is 30 kHz, second resource allocation information of a plurality of resource blocks having an interleaved structure and first resource allocation information of the allocated LBT subband may be sent to the UE through an indicator according to a bitmap scheme.

[0419] That is, the detailed positions of a plurality of resource blocks and continuous LBT subbands having an interleaved structure may be encoded individually or together by a value of each bit having a specific size and included in the DCI.

[0420] When the detailed positions of multiple resource blocks with an interleaved structure and continuously allocated LBT subbands are encoded together and sent to the UE through an indicator, the information can be mapped to an indicator indicating the indexes of multiple resource blocks with an interleaved structure and continuously allocated LBT subbands, and an indicator indicating each mapping state can be included in the DCI and sent to the UE.

[0421] Thereafter, in S24020, the base station may receive a PUSCH from the UE through an LBT subband continuously allocated to the UE via DCI and a plurality of resource blocks allocated in an interleaved structure.

[0422] The description according to the present disclosure is only for example, and those skilled in the art will appreciate that, without departing from the technical concept or essential features of the present disclosure, the embodiments of the present disclosure can be easily changed into other detailed forms. Therefore, the embodiments should be understood as examples rather than limiting in all aspects. For example, each element mentioned in singular form can be implemented in a distributed manner, and the elements mentioned in a distributed form can also be implemented in a combined form.

[0423] The scope of the present disclosure is defined by the appended claims rather than the detailed description, and the meaning and scope of the claims and all modifications or modified forms derived from the concept of equivalents thereof should be construed as being included in the scope of the present disclosure.

Claims

1. A terminal in a wireless communication system, the terminal include: Communication module; as well as a processor configured to control the communication module, Wherein, the processor is configured to: Receive downlink control information DCI used to schedule a physical uplink shared channel PUSCH from a base station, The DCI includes first resource allocation information for indicating at least one interlace included in the interlace allocation of a plurality of resource blocks included in at least one resource block set, and sending the PUSCH to the base station through the multiple resource blocks, The first resource allocation information indicates the at least one interlace using different schemes based on the subcarrier spacing SCS configured to the active bandwidth part BWP.

2. The terminal according to claim 1, in, The different schemes include a bitmap scheme and a resource indication value (RIV) scheme.

3. The terminal according to claim 1, in, The number of bits of the first resource allocation information varies depending on the SCS configured to the active BWP.

4. The terminal according to claim 3, in, When the SCS is 30 kHz, each of the at least one interlace is represented by a corresponding bit value included in the first resource allocation information based on the bitmap scheme.

5. The terminal according to claim 3, in, When the SCS is 15 kHz, the first resource allocation information indicates a starting index of the at least one interlace based on the RIV scheme and the number of the at least one interlace.

6. The terminal according to claim 1, in, The DCI further includes second resource allocation information for allocating the at least one resource block set including the plurality of resource blocks, and The second resource allocation information is related to the starting index and quantity of the at least one resource block set.

7. The terminal according to claim 6, in, The second resource allocation information is used to allocate the at least one resource block set included in the active BWP.

8. The terminal according to claim 7, in, At least one resource block included in each of the at least one interlace is arranged at specific intervals in the active BWP, and The at least one resource block set is continuously allocated within the active BWP based on the second allocation information.

9. The terminal according to claim 6, in, The first resource allocation information and the second resource allocation information are encoded together and included in the DCI.

10. The terminal according to claim 1, in, The plurality of resource blocks have an interleaved structure on the at least one resource block set in which an operation for channel access is performed.

11. A method for operating a terminal in a wireless communication system, the method include: Receive downlink control information DCI used to schedule a physical uplink shared channel PUSCH from a base station, The DCI includes first resource allocation information for indicating at least one interlace included in the interlace allocation of a plurality of resource blocks included in at least one resource block set; and sending the PUSCH to the base station through the multiple resource blocks, The first resource allocation information indicates the at least one interlace using different schemes based on the subcarrier spacing SCS configured to the active bandwidth part BWP.

12. The terminal according to claim 11, in, The different schemes include a bitmap scheme and a resource indication value (RIV) scheme.

13. The method according to claim 11, in, The number of bits of the first resource allocation information varies depending on the SCS configured to the active BWP.

14. The method according to claim 13, in, When the SCS is 30 kHz, each of the at least one interlace is represented by a corresponding bit value included in the first resource allocation information based on the bitmap scheme.

15. The method according to claim 13, in, When the SCS is 15 kHz, the first resource allocation information indicates a starting index of the at least one interlace based on the RIV scheme and the number of the at least one interlace.

16. The method according to claim 11, in, The DCI further includes second resource allocation information for allocating the at least one resource block set including the plurality of resource blocks, and The second resource allocation information is related to the starting index and quantity of the at least one resource block set.

17. The method according to claim 16, in, The second resource allocation information is used to allocate the at least one resource block set included in the active BWP.

18. The method according to claim 17, in, At least one resource block included in each of the at least one interlace is arranged at specific intervals in the active BWP, and The at least one resource block set is continuously allocated within the active BWP based on the second allocation information.

19. The method according to claim 16, in, The first resource allocation information and the second resource allocation information are encoded together and included in the DCI.

20. The method according to claim 11, in, The plurality of resource blocks have an interleaved structure on the at least one resource block set in which an operation for channel access is performed.

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