Method and apparatus for performing sidelink communication in wireless communication system

Abstract

A method and apparatus for performing communication in a wireless communication system are disclosed. According to an embodiment of the present invention, a method implemented by a first terminal comprises: receiving configuration information related to one or more resource block (RB) sets for sidelink (SL) transmission from a base station; and based on detecting a consistent SL Listen Before Talk (LBT) failure for a particular RB set among the one or more RB sets, transmitting a Media Access Control (MAC) Control Element (CE) related to the consistent SL LBT failure to the base station, where the MAC CE may include information indicating that the consistent SL LBT failure has been detected for the particular RB set.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for performing uplink communication in a wireless communication system. Background Art

[0002] A mobile communication system has been developed to provide voice services while ensuring user mobility. However, the mobile communication system has been extended to data services as well as voice services, and currently, the explosive growth of services has led to resource shortages, and users have demanded faster services, thus requiring more advanced mobile communication systems.

[0003] The overall requirement for the next generation of mobile communication systems should be able to support the accommodation of explosive data services, a significant increase in the transmission rate per user, the accommodation of a significantly increased number of connected devices, very low end-to-end latency and high energy efficiency. To this end, various technologies have been studied, including dual connectivity, massive multiple-input multiple-output (massive MIMO), in-band full-duplex, non-orthogonal multiple access (NOMA), ultra-wideband support, and device networking. Summary of the invention

[0004] Technical issues

[0005] The technical problem of the present disclosure is to provide a method and apparatus for performing side link communication in a wireless communication system.

[0006] The technical problem of the present disclosure is to provide a method and device for detecting SL LBT in units of SL resource pools or / and RB sets.

[0007] The technical problem of the present disclosure is to provide a method and apparatus for reporting information related to a consistent SL LBT failure when a consistent SL LBT failure is triggered.

[0008] Technical problems achieved by the present disclosure are not limited to the above-mentioned technical purposes, and other technical problems not described herein will be clearly understood by those skilled in the relevant art from the following description.

[0009] Technical Solution

[0010] According to one embodiment of the present disclosure, a method performed by a first user equipment (UE) in a wireless communication system may include: receiving configuration information related to at least one resource block (RB) set for sidelink (SL) transmission from a base station; and based on detecting a consistent SL LBT (listen before talk) failure for a specific RB set among the at least one RB set, sending a MAC (media access control) CE (control element) related to the consistent SL LBT failure to the base station, and the MAC CE may include information indicating that a consistent SL LBT failure has been detected for the specific RB set.

[0011] According to one embodiment of the present disclosure, a method performed by a base station in a wireless communication system may include: sending configuration information related to at least one resource block (RB) set for sidelink (SL) transmission to a first user equipment (UE); and based on detecting a consistent SL LBT (listen before talk) failure for a specific RB set among the at least one RB set, receiving a MAC (media access control) CE (control element) related to the consistent SL LBT failure from the first UE, and the MAC CE may include information indicating that a consistent SL LBT failure has been detected for the specific RB set.

[0012] Beneficial Effects

[0013] According to one embodiment of the present disclosure, a method and apparatus for performing sidelink communication in a wireless communication system may be provided.

[0014] According to an embodiment of the present disclosure, a method and device for detecting SL LBT in units of SL resource pools or / and RB sets may be provided.

[0015] According to one embodiment of the present disclosure, a method and apparatus for reporting information related to a consistent SL LBT failure when a consistent SL LBT failure is triggered may be provided.

[0016] According to one embodiment of the present disclosure, by reporting a MAC CE indicating a resource pool / RB set that detects / triggering an SL LBT failure to the base station, the base station is able to identify the resources where the SL LBT failure occurs in more detail.

[0017] Effects achievable by the present disclosure are not limited to the above-described effects, and other effects not described herein may be clearly understood by those skilled in the art through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are included as a part of the detailed description for understanding the present disclosure, provide embodiments of the present disclosure and describe technical features of the present disclosure through the detailed description.

[0019] Figure 1 The diagram shows a structure of a wireless communication system to which the present disclosure can be applied.

[0020] Figure 2 The figure illustrates a frame structure in a wireless communication system to which the present disclosure can be applied.

[0021] Figure 3 The diagram illustrates a resource grid in a wireless communication system to which the present disclosure may be applied.

[0022] Figure 4The figure illustrates physical resource blocks in a wireless communication system to which the present disclosure can be applied.

[0023] Figure 5 The diagram illustrates a time slot structure in a wireless communication system to which the present disclosure can be applied.

[0024] Figure 6 Physical channels used in a wireless communication system to which the present disclosure can be applied and a general signal transmission and reception method using the physical channels are illustrated.

[0025] Figure 7 The diagram illustrates a process for performing V2X or SL communication according to a transmission mode in a wireless communication system to which the present disclosure can be applied.

[0026] Figure 8 Illustration of broadcast types used for V2X or SL communication in a wireless communication system to which the present disclosure can be applied.

[0027] Fig. 9 is a diagram for explaining a process in which a first UE performs communication according to an embodiment of the present disclosure.

[0028] Fig.10 is a diagram for explaining a process in which a base station performs communication according to an embodiment of the present disclosure.

[0029] Fig.11 is a diagram for explaining signaling procedures of a base station, a first UE, and a second UE according to an embodiment of the present disclosure.

[0030] Fig.12 is a diagram for explaining a (SL) LBT failure MAC CE structure according to an embodiment of the present disclosure.

[0031] Fig.13 is a block diagram for explaining a wireless communication system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description to be disclosed by the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, rather than to represent the only embodiment in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art will appreciate that the present disclosure can be implemented without these specific details.

[0033] In some cases, well-known structures and devices may be omitted, or may be shown in the form of a block diagram based on the core functions of each structure and device in order to prevent ambiguity of the concepts of the present disclosure.

[0034] In the present disclosure, when an element is referred to as being "connected", "combined" or "linked" to another element, it may include an indirect connection relationship between another element and a direct connection relationship. In addition, in the present disclosure, the term "comprising" or "having" specifies the presence of the mentioned features, steps, operations, components and / or elements, but does not exclude the presence or addition of one or more other features, stages, operations, components, elements and / or groups thereof.

[0035] In the present invention, terms such as "first", "second", etc. are only used to distinguish one element from another element and are not used to limit the elements, and unless otherwise specified, they do not limit the order or importance between the elements. Therefore, within the scope of the present disclosure, the first element in an embodiment may be referred to as the second element in another embodiment, and similarly, the second element in an embodiment may be referred to as the first element in another embodiment.

[0036] The terms used in this disclosure are intended to describe specific embodiments rather than to limit the claims. As used in the description of the embodiments and the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term "and / or" used in this disclosure may refer to one of the related enumerated items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise stated, the " / " between words in the present invention has the same meaning as "and / or".

[0037] The present disclosure describes a wireless communication network or a wireless communication system, and operations performed in the wireless communication network may be performed in a process in which a device (e.g., a base station) controlling the corresponding wireless communication network controls the network and sends or receives signals, or may be performed in a process in which a terminal associated with the corresponding wireless network sends or receives signals between the network or the terminal.

[0038] In the present disclosure, sending or receiving a channel includes the meaning of sending or receiving information or signals through the corresponding channel. For example, sending a control channel means sending control information or control signals through the control channel. Similarly, sending a data channel means sending data information or data signals through the data channel.

[0039] Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In the downlink, the transmitter may be a part of a base station, and the receiver may be a part of a terminal. In the uplink, the transmitter may be a part of a terminal, and the receiver may be a part of a base station. The base station may be expressed as a first communication device, and the terminal may be expressed as a second communication device. The base station (BS) may be replaced by terms such as a fixed station, a node B, an eNB (evolved node B), a gNB (next generation node B), a BTS (base station transceiver system), an access point (AP), a network (5G network), an AI (artificial intelligence) system / module, an RSU (roadside unit), a robot, a drone (UAV: unmanned aerial vehicle), an AR (augmented reality) device, a VR (virtual reality) device, and the like. In addition, the terminal may be fixed or mobile, and may be replaced by terms such as UE (user equipment), MS (mobile station), UT (user terminal), MSS (mobile subscriber station), SS (subscriber station), AMS (advanced mobile station), WT (wireless terminal), MTC (machine type communication) device, M2M (machine to machine) device, D2D (device to device) device, vehicle, RSU (roadside unit), robot, AI (artificial intelligence) module, drone (UAV: unmanned aerial vehicle), AR (augmented reality) device, VR (virtual reality) device, etc.

[0040] The following description may be used for various radio access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, etc. CDMA may be implemented by, for example, UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA may be implemented by radio technologies such as GSM (Global System for Mobile Communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA may be implemented by radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802-20, E-UTRA (Evolved UTRA), etc. UTRA is part of UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is part of E-UMTS (Evolved UMTS) using E-UTRA, and LTE-A (Advanced) / LTE-A pro is an advanced version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an advanced version of 3GPP LTE / LTE-A / LTE-A pro.

[0041] In order to make the description clearer, the description is based on the 3GPP communication system (e.g., LTE-A, NR), but the technical idea of ​​the present disclosure is not limited to this. LTE means the technology after 3GPP TS (Technical Specification) 36.xxx version 8. Specifically, the LTE technology in or after 3GPP TS 36.xxx version 10 is called LTE-A, and the LTE technology in or after 3GPP TS 36.xxx version 13 is called LTE-A pro. 3GPP NR means the technology in or after TS 38.xxx version 15. LTE / NR can be referred to as a 3GPP system. "xxx" means the detailed number of the standard document. LTE / NR can generally be referred to as a 3GPP system. For the background technology, terms, abbreviations, etc. used to describe the present disclosure, reference can be made to the matters described in the standard documents disclosed before the present disclosure. For example, reference can be made to the following documents.

[0042] For 3GPP LTE, reference may be made to TS 36.211 (Physical Channels and Modulation), TS 36.212 (Multiplexing and Channel Coding), TS 36.213 (Physical Layer Procedures), TS 36.300 (Overall Description), and TS 36.331 (Radio Resource Control).

[0043] For 3GPP NR, you can refer to TS 38.211 (Physical channels and modulation), TS 38.212 (Multiplexing and channel coding), TS 38.213 (Physical layer procedures for control), TS 38.214 (Physical layer procedures for data), TS 38.300 (NR and NG-RAN (Next Generation Radio Access Network) overall description), and TS 38.331 (Radio Resource Control Protocol Specification).

[0044] Abbreviations of terms that may be used in the present disclosure are defined as follows.

[0045] - BM: Beam Management

[0046] - CQI: Channel Quality Indicator

[0047] - CRI: Channel State Information-Reference Signal Resource Indicator

[0048] - CSI: Channel State Information

[0049] - CSI-IM: Channel State Information-Interference Measurement

[0050] - CSI-RS: Channel State Information-Reference Signal

[0051] - DMRS: Demodulation Reference Signal

[0052] - FDM: Frequency Division Multiplexing

[0053] - FFT: Fast Fourier Transform

[0054] - IFDMA: Interleaved Frequency Division Multiple Access

[0055] - IFFT: Inverse Fast Fourier Transform

[0056] - L1-RSRP: Layer 1 reference signal received power

[0057] - L1-RSRQ: Layer 1 reference signal reception quality

[0058] - MAC: Media Access Control

[0059] - NZP: Non Zero Power

[0060] - OFDM: Orthogonal Frequency Division Multiplexing

[0061] - PDCCH: Physical Downlink Control Channel

[0062] - PDSCH: Physical Downlink Shared Channel

[0063] - PMI: Precoding Matrix Indicator

[0064] - RE: Resource Element

[0065] - RI: Rank Indicator

[0066] - RRC: Radio Resource Control

[0067] - RSSI: Received Signal Strength Indicator

[0068] - Rx: Receive

[0069] - QCL: Quasi Co-sited

[0070] - SINR: Signal to Interference and Noise Ratio

[0071] - SSB (or SS / PBCH block): Synchronization signal block (including PSS (primary synchronization signal), SSS (secondary synchronization signal) and PBCH (physical broadcast channel))

[0072] - TDM: Time Division Multiplexing

[0073] - TRP: Transmit and Receive Point

[0074] - TRS: Tracking Reference Signal

[0075] - Tx: Send

[0076] - UE: User Equipment

[0077] - ZP: Zero Power

[0078] Overall system

[0079] As more communication devices require higher capacity, there has been a demand for improved mobile broadband communications compared to existing radio access technologies (RATs). In addition, large-scale MTC (machine type communication) that provides various services anytime and anywhere by connecting multiple devices and things is also one of the main issues to be considered in the next generation of communications. In addition, the design of communication systems considering services / terminals that are sensitive to reliability and latency is also discussed. Therefore, the introduction of next-generation RATs considering eMBB (enhanced mobile broadband communication), mMTC (massive MTC), URLLC (ultra-reliable low-latency communication), etc. is discussed, and for convenience, the corresponding technology is referred to as NR in this disclosure. NR is an expression representing an example of 5G RAT.

[0080] The new RAT system including NR uses an OFDM transmission method or a transmission method similar thereto. The new RAT system may follow OFDM parameters different from those of LTE. Alternatively, the new RAT system follows the parameters of the existing LTE / LTE-A as is, but may support a wider system bandwidth (e.g., 100 MHz). Alternatively, one cell may support multiple parameter sets. In other words, terminals operating according to different parameter sets may coexist in one cell.

[0081] A parameter set corresponds to one subcarrier spacing in the frequency domain. As the reference subcarrier spacing is scaled by an integer N, different parameter sets can be defined.

[0082] Figure 1 The diagram illustrates a structure of a wireless communication system to which the present disclosure can be applied.

[0083] refer to Figure 1 , NG-RAN is configured with gNBs that provide the control plane (RRC) protocol side for the NG-RA (NG Radio Access) user plane (i.e., the new AS (Access Stratum) sublayer / PDCP (Packet Data Convergence Protocol) / RLC (Radio Link Control) / MAC / PHY) and the UE. The gNBs are interconnected through the Xn interface. In addition, the gNBs are connected to the NGC (Next Generation Core) through the NG interface. More specifically, the gNB is connected to the AMF (Access and Mobility Management Power) through the N2 interface, and to the UPF (User Plane Function) through the N3 interface.

[0084] Figure 2 The diagram illustrates a frame structure in a wireless communication system to which the present disclosure may be applied.

[0085] The NR system may support multiple parameter sets. Here, the parameter set may be defined by subcarrier spacing and cyclic prefix (CP) overhead. Here, multiple subcarrier spacings may be derived by scaling the basic (reference) subcarrier spacing by an integer N (or, μ). In addition, although it is assumed that very low subcarrier spacings are not used in very high carrier frequencies, the parameter set used may be selected independently of the frequency band. In addition, various frame structures according to multiple parameter sets may be supported in the NR system.

[0086] In the following, OFDM parameter sets and frame structures that can be considered in the NR system are described. Multiple OFDM parameter sets supported in the NR system can be defined as shown in Table 1 below.

[0087]

[0088] NR supports multiple parameter sets (or subcarrier spacing (SCS)) for supporting various 5G services. For example, when the SCS is 15kHz, the wide area of ​​the traditional cellular band is supported; and when the SCS is 30kHz / 60kHz, dense cities, lower latency, and wider carrier bandwidth are supported; and when the SCS is 60kHz or higher, bandwidths exceeding 24.25GHz are supported to overcome phase noise. The NR band is defined as two types (FR1, FR2) of frequency ranges. FR1, FR2 can be configured as shown in Table 2 below. In addition, FR2 can mean millimeter wave (mmW).

[0089]

[0090] Regarding the frame structure in the NR system, the sizes of various fields in the time domain are expressed as T c =1 / (Δf max ·N f ) is a multiple of the time unit. Here, Δf max i is 480·10 3 Hz, and N f is 4096. Downlink and uplink transmissions are configured (organized) to have duration T f= 1 / (Δf max N f / 100)·T c =10ms radio frame. Here, the radio frame is configured with 10 subframes, each of which has T sf =(Δf max N f / 1000)·T c In this case, there may be one frame set for the uplink and one frame set for the downlink. Furthermore, the transmission in the i-th uplink frame from the terminal should start T earlier than the corresponding downlink frame in the corresponding terminal.TA =(N TA +N TA,offset )T c For subcarrier spacing configuration μ, the time slots are arranged in n subframes. s μ ∈{0,..., N slot subframe,μ -1} and in the radio frame the number is incremented by n s,f μ ∈{0,..., N slot frame,μ -1}. A time slot is configured with N symb slot consecutive OFDM symbols, and N symb slot Determined according to CP. Time slot n in a subframe s μ The beginning of the OFDM symbol n in the same subframe s μ N symb slot All terminals may not perform transmission and reception at the same time, which means that all OFDM symbols of a downlink time slot or an uplink time slot may not be used.

[0091] Table 3 shows the number of OFDM symbols per time slot in a normal CP (N symb slot ), the number of time slots per radio frame (N slot frame,μ ) and the number of time slots per subframe (N slot subframe,μ ), and Table 4 represents the number of OFDM symbols per slot, the number of slots per radio frame, and the number of slots per subframe in the extended CP.

[0092]

[0093]

[0094] Figure 2 This is an example of μ=2 (SCS is 60kHz), see Table 3, 1 subframe can include 4 time slots. Figure 21 subframe = {1,2,4} shown in is an example, and the number of time slots that can be included in 1 subframe is defined in Table 3 or Table 4. In addition, a micro-time slot may include 2, 4 or 7 symbols or more or less symbols. Regarding the physical resources in the NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, etc. can be considered. In the following, the physical resources that can be considered in the NR system will be described in detail. First, with respect to antenna ports, antenna ports are defined so that the channel carrying the symbols in the antenna port can be inferred from the channel carrying other symbols in the same antenna port. When the large-scale properties of the channel on which the symbols in one antenna port are carried can be inferred from the channel carrying the symbols of another antenna port, it can be said that the two antenna ports are in a QC / QCL (quasi-co-located or quasi-co-located) relationship. In this case, the large-scale properties include at least one of delay spread, Doppler spread, frequency shift, average received power, and receive timing.

[0095] Figure 3 A resource grid in a wireless communication system to which the present disclosure may be applied is illustrated.

[0096] refer to Figure 3 , which graphically depicts a resource grid configuration with N in the frequency domain RB μ N sc RB subcarriers, and one subframe is configured with 14·2 μ OFDM symbols, but not limited to this. In the NR system, the transmitted signal consists of 2 μ N symb （μ） OFDM symbols and N RB μ N sc RB Here, N RB μ ≤ N RB max,μ . N RB max,μ represents the maximum transmission bandwidth, which may differ between uplink and downlink and between parameter sets. In this case, one resource grid can be configured for each μ and antenna port p. Each element of the resource grid for μ and antenna port p is called a resource element and is uniquely identified by an index pair (k, l'). Here, k = 0, ..., N RB μ N sc RB -1 is the index in the frequency domain, and l'=0,...,2 μ N symb （μ）-1 refers to the symbol position in the subframe. When referring to a resource element in a slot, an index pair (k, l) is used.

[0097] Here, l=0,..., N symb μ -1. The resource element (k, l') for μ and antenna port p corresponds to the complex value a k,l' （p,μ） When there is no risk of confusion or when no specific antenna port or parameter set is specified, the indices p and μ may be dropped and the complex value may be a k,l' （p） or a k,l' In addition, a resource block (RB) is defined as N sc RB =12 consecutive subcarriers.

[0098] Point A serves as a common reference point for the resource block grid and is obtained as follows.

[0099] -OffsetToPointA for the primary cell (PCell) downlink represents the frequency offset between point A and the lowest subcarrier of the lowest resource block overlapping with the SS / PBCH block used by the terminal for initial cell selection. Assuming a subcarrier spacing of 15 kHz for FR1 and a subcarrier spacing of 60 kHz for FR2, it is expressed in resource blocks.

[0100] - absoluteFrequencyPointA represents the frequency position of point A, expressed in ARFCN (Absolute Radio Frequency Channel Number).

[0101] For subcarrier spacing configuration μ, the common resource blocks are numbered from 0 upwards in the frequency domain. The center of subcarrier 0 of common resource block 0 for subcarrier spacing configuration μ is the same as "point A. The common resource block number n for subcarrier spacing configuration μ in the frequency domain CRB μ The relationship between and resource elements (k, l) is given by the following equation 1.

[0102] [Formula 1]

[0103]

[0104] In Equation 1, k is defined relative to point A, so that k = 0 corresponds to a subcarrier centered at point A. Physical resource blocks are numbered from 0 to N in a bandwidth part (BWP). BWP,i size,μ -1 numbering and i is the number of the BWP. Physical resource block n in BWP i PRB and public resource block n CRBThe relationship between is given by the following formula 2.

[0105] [Formula 2]

[0106]

[0107] N BWP,i start,μ is the common resource block where the BWP starts relative to common resource block 0.

[0108] Figure 4 The figure illustrates a physical resource block in a wireless communication system to which the present disclosure can be applied. Figure 5 The diagram illustrates a time slot structure in a wireless communication system to which the present disclosure may be applied.

[0109] refer to Figure 4 and Figure 5 , a slot includes a plurality of symbols in the time domain. For example, for a normal CP, 1 slot includes 7 symbols, but for an extended CP, 1 slot includes 6 symbols.

[0110] A carrier includes multiple subcarriers in the frequency domain. An RB (resource block) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A BWP (bandwidth part) is defined as multiple consecutive (physical) resource blocks in the frequency domain and may correspond to one parameter set (e.g., SCS, CP length, etc.). A carrier may include up to N (e.g., 5) BWPs. Data communication may be performed through activated BWPs, and only one BWP may be activated for one terminal. In a resource grid, each element is called a resource element (RE) and may map one complex symbol.

[0111] In the NR system, each component carrier (CC) can support up to 400MHz. If a terminal operating in such a wideband CC always operates to turn on the radio frequency (FR) chip for the entire CC, the terminal battery consumption may increase. Alternatively, when considering multiple application scenarios operating in one wideband CC (e.g., eMBB, URLLC, Mmtc, V2X, etc.), different parameter sets (e.g., subcarrier spacing, etc.) may be supported in each frequency band in the corresponding CC. Alternatively, each terminal may have different capabilities for the maximum bandwidth. Taking this into account, the base station may instruct the terminal to operate only in part of the bandwidth, rather than in the full bandwidth of the wideband CC, and for convenience, the corresponding part of the bandwidth is defined as a bandwidth part (BWP). The BWP may be configured with continuous RBs on the frequency axis and may correspond to a parameter set (e.g., subcarrier spacing, CP length, slot / microslot duration).

[0112] At the same time, even in one CC configured to the terminal, the base station can configure multiple BWPs. For example, a BWP occupying a relatively small frequency domain can be configured in the PDCCH monitoring time slot, and the PDSCH indicated by the PDCCH can be scheduled in a larger BWP. Alternatively, when the UE is congested in a specific BWP, other BWPs can be configured for some terminals for load balancing. Alternatively, considering the frequency domain inter-cell interference elimination between adjacent cells, etc., some full-bandwidth middle spectrums can be excluded, and BWPs on two edges can be configured in the same time slot. In other words, the base station can configure at least one DL / UL BWP to a terminal associated with a broadband CC. The base station can activate at least one DL / UL BWP in the configured DL / UL BWP at a specific time (through L1 signaling or MAC CE (control element) or RRC signaling, etc.). In addition, the base station can indicate switching to other configured DL / UL BWPs (through L1 signaling or MAC CE or RRC signaling, etc.). Alternatively, based on a timer, when the timer value expires, it can switch to a determined DL / UL BWP. Here, the activated DL / UL BWP is defined as the active DL / UL BWP. However, when the terminal performs the initial access procedure or sets up the RRC connection, the configuration on the DL / UL BWP may not be received, so the DL / UL BWP assumed by the terminal in these cases is defined as the initial active DL / UL BWP.

[0113] Figure 6 Physical channels used in a wireless communication system to which the present disclosure can be applied and a general signal transmission and reception method using the physical channels are illustrated.

[0114] In a wireless communication system, a terminal receives information from a base station through a downlink and transmits information to the base station through an uplink. The information sent and received by the base station and the terminal includes data and various control information, and there are various physical channels according to the type / purpose of the information they send and receive.

[0115] When the terminal is turned on or newly enters a cell, it performs an initial cell search including synchronization with a base station (S601). For the initial cell search, the terminal can synchronize with the base station by receiving a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station, and obtain information such as a cell identifier (ID). Then, the terminal can obtain broadcast information in the cell by receiving a physical broadcast channel (PBCH) from the base station. At the same time, the terminal can check the downlink channel status by receiving a downlink reference signal (DL RS) in the initial cell search phase.

[0116] The terminal that has completed the initial cell search may obtain more detailed system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) according to information carried in the PDCCH (S602).

[0117] Meanwhile, when the terminal accesses the base station for the first time or has no radio resources for signal transmission, it may perform a random access (RACH) procedure on the base station (S603 to S606). For the random access procedure, the terminal may send a specific sequence as a preamble through a physical random access channel (PRACH) (S603 and S605), and may receive a response message to the preamble through a PDCCH and a corresponding PDSCH (S604 and S606). The contention-based RACH may additionally perform a contention resolution procedure.

[0118] The terminal that subsequently performs the above process may perform PDCCH / PDSCH reception (S607) and PUSCH (Physical Uplink Shared Channel) / PUCCH (Physical Uplink Control Channel) transmission (S608) as a general uplink / downlink signal transmission process. Specifically, the terminal receives downlink control information (DCI) through the PDCCH. Here, DCI includes control information such as resource allocation information for the terminal, and the format varies according to its purpose of use.

[0119] At the same time, the control information sent by the terminal to the base station through the uplink or received by the terminal from the base station includes downlink / uplink ACK / NACK (acknowledgement / non-acknowledgement) signal, CQI (channel instruction indicator), PMI (precoding matrix indicator), RI (rank indicator), etc. For the 3GPP LTE system, the terminal can send the above-mentioned CQI / PMI / RI and other control information through PUSCH and / or PUCCH.

[0120] Table 5 shows an example of the DCI format in the NR system.

[0121]

[0122] Referring to Table 5, DCI formats 0_0, 0_1, and 0_2 may include resource information (e.g., UL / SUL (supplementary UL), frequency resource allocation, time resource allocation, frequency hopping, etc.), information related to a transport block (TB) (e.g., MCS (modulation coding and scheme), NDI (new data indicator), RV (redundancy version), etc.), information related to HARQ (hybrid-automatic repeat and request) (e.g., process number, DAI (downlink assignment index), PDSCH-HARQ feedback timing, etc.), information related to multiple antennas (e.g., DMRS sequence initialization information, antenna port, CSI request, etc.), power control information related to scheduling of PUSCH (e.g., PUSCH power control, etc.), and control information included in each DCI format may be predefined.

[0123] DCI format 0_0 is used to schedule PUSCH in one cell. Information included in DCI format 0_0 is CRC (Cyclic Redundancy Check) scrambled by C-RNTI (Cell Radio Network Temporary Identifier) ​​or CS-RNTI (Configured Scheduling RNTI) or MCS-C-RNTI (Modulation Coding Scheme Cell RNTI) and transmitted.

[0124] DCI format 0_1 ​​is used to indicate the scheduling of one or more PUSCHs or to configure grant (CG) downlink feedback information to a terminal in one cell. The information included in DCI format 0_1 ​​is scrambled and transmitted by C-RNTI or CS-RNTI or SP-CSI-RNTI (semi-persistent CSI RNTI) or MCS-C-RNTI.

[0125] DCI format 0_2 is used to schedule PUSCH in one cell. Information included in DCI format 0_2 is scrambled and transmitted by C-RNTI, CS-RNTI, SP-CSI-RNTI, or MCS-C-RNTI.

[0126] Next, DCI formats 1_0, 1_1 and 1_2 may include resource information (e.g., frequency resource allocation, time resource allocation, VRB (virtual resource block) -PRB (physical resource block) mapping, etc.), information related to transport blocks (TBs) (e.g., MCS, NDI, RV, etc.), information related to HARQ (e.g., process number, DAI, PDSCH-HARQ feedback timing, etc.), information related to multiple antennas (e.g., antenna ports, TCI (transmission configuration indicator), SRS (sounding reference signal) requests, etc.), information related to PUCCH scheduling regarding PDSCH (e.g., PUCCH power control, PUCCH resource indicator, etc.), and the control information included in each DCI format may be predefined.

[0127] DCI format 1_0 is used to schedule PDSCH in one DL cell. Information included in DCI format 1_0 is CRC scrambled and transmitted by C-RNTI or CS-RNTI or MCS-C-RNTI.

[0128] DCI format 1_1 is used to schedule PDSCH in one cell. Information included in DCI format 1_1 is CRC scrambled and transmitted by C-RNTI or CS-RNTI or MCS-C-RNTI.

[0129] DCI format 1_2 is used to schedule PDSCH in one cell. Information included in DCI format 1_2 is CRC scrambled and transmitted by C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0130] V2X (Vehicle-to-Everything) / Sidelink (SL: Sidelink) communication

[0131] Figure 7 Illustration of a process for performing V2X or SL communication according to a transmission mode in a wireless communication system to which the present disclosure can be applied.

[0132] Figure 7 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure. In various embodiments of the present disclosure, a transmission mode may be referred to as a mode or a resource allocation mode. Hereinafter, for convenience of explanation, a transmission mode in LTE may be referred to as an LTE transmission mode, and a transmission mode in NR may be referred to as an NR resource allocation mode.

[0133] For example, Figure 7 (a) illustrates the operation of the UE related to LTE transmission mode 1 or LTE transmission mode 3. Alternatively, for example, Figure 7 (a) illustrates the operation of the UE related to NR resource allocation mode 1. For example, LTE transmission mode 1 may be applied to general SL communication, and LTE transmission mode 3 may be applied to V2X communication.

[0134] For example, Figure 7 (b) illustrates the operation of a UE associated with LTE transmission mode 2 or LTE transmission mode 4. Alternatively, for example, Figure 7 (b) illustrates the operation of the UE associated with NR resource allocation mode 2.

[0135] refer to Figure 7(a), in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, the base station may schedule SL resources for the UE to use for SL transmission (S8000). For example, the base station may send information related to the SL resources and / or information related to the UL resources to the first UE. For example, the UL resources may include PUCCH resources and / or PUSCH resources. For example, the UL resources may be resources for reporting SL HARQ feedback to the base station.

[0136] For example, the first UE may receive information related to dynamic grant (DG) resources and / or information related to configured grant (CG) resources from the base station. For example, the CG resources may include CG type 1 resources or CG type 2 resources. In the present disclosure, the DG resources may be resources that the base station configures / allocates to the first UE via DCI. In the present disclosure, the CG resources may be (periodic) resources that the base station configures / allocates to the first UE via DCI and / or RRC messages. For example, in the case of CG type 1 resources, the base station may send an RRC message including information related to the CG resources to the first UE. For example, in the case of CG type 2 resources, the base station may send an RRC message including information related to the CG resources to the first UE, and the base station may send a DCI related to the activation or release of the CG resources to the first UE.

[0137] The first UE may transmit a PSCCH (eg, sidelink control information (SCI) or first-stage SCI) to the second UE based on resource scheduling ( S8010 ).

[0138] The first UE may transmit a PSSCH (eg, a second stage SCI, a MAC protocol data unit (PDU), data, etc.) related to the PSCCH to the second UE ( S8020 ).

[0139] The first UE may receive a PSFCH related to the PSCCH / PSSCH from the second UE (S8030). For example, HARQ feedback information (eg, NACK information or ACK information) can be received from the second UE via the PSFCH.

[0140] The first UE may send / report HARQ feedback information to the base station via PUCCH or PUSCH (S8040). For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on the HARQ feedback information received from the second UE. For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on a pre-set rule. For example, the DCI may be DCI for SL scheduling. For example, the format of the DCI may be DCI format 3_0 or DCI format 3_1.

[0141] refer to Figure 7(b), in LTE transmission mode 2, LTE transmission mode 4 or NR resource allocation mode 2, the UE may determine the SL transmission resources within the SL resources set by the base station / network or the preset SL resources. For example, the set SL resources or the pre-configured SL resources may be a resource pool. For example, the UE may autonomously select or schedule resources for SL transmission. For example, the UE may perform SL communication by autonomously selecting resources within a configured resource pool. For example, the UE may perform a sensing and resource (re)selection process to autonomously select resources within a selection window. For example, sensing may be performed based on subchannels.

[0142] The first UE that has selected a resource in the resource pool may use the resource to send a PSCCH (eg, SCI or first-stage SCI) to a second UE ( S8010 ).

[0143] The first UE may transmit a PSSCH (eg, second stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second UE ( S8020 ).

[0144] The first UE may receive a PSFCH related to the PSCCH / PSSCH from the second UE ( S8030 ).

[0145] refer to Figure 7 (a) or Figure 7 (b), for example, the first UE may send SCI to the second UE on the PSCCH. Or, for example, the first UE may send two consecutive SCIs (e.g., 2-phase SCI) to the second UE on the PSCCH and / or PSSCH. In such a case, the second UE may decode two consecutive SCIs (e.g., 2-phase SCI) to receive the PSSCH from the first UE. In the present disclosure, the SCI sent on the PSCCH may be referred to as the first (first) SCI, the first SCI, the first phase SCI, or the first phase SCI format, and the SCI sent on the PSSCH may be referred to as the second (second) SCI, the second SCI, the second phase SCI, or the second phase SCI format. For example, the first phase SCI format may include SCI format 1-A, and the second phase SCI format may include SCI format 2-A and / or SCI format 2-B.

[0146] refer to Figure 7 (a) or Figure 7 (b), in step S8030, the first UE may receive the PSFCH based on the description to be described below. For example, the first UE and the second UE may determine the PSFCH resources based on the description to be described below, and the second UE may send HARQ feedback to the first UE using the PSFCH resources.

[0147] The UE procedure for reporting HARQ-ACK on the sidelink is described, as specified in TS 38.213.

[0148] The SCI format for scheduling PSSCH reception may instruct the UE to send a PSFCH including HARQ-ACK information in response to PSSCH reception. The UE provides HARQ-ACK information including ACK or NACK or only NACK.

[0149] The number of timeslots in the resource pool during the period of PSFCH transmission opportunity resources may be provided to the UE via sl-PSFCH-Period. If the number of timeslots is 0, PSFCH transmissions in the resource pool for the UE are disabled.

[0150] If k mod N PSSCH PSFCH = 0, then the UE expects time slot t' k SL (0≤k <T' max ) includes PSFCH transmission opportunity resources, where t' k SL Defined in TS 38.214, T' max is the number of time slots belonging to the resource pool within 10240 milliseconds according to TS 38.214, and N PSSCH PSFCH Provided by sl-PSFCH-Period.

[0151] Higher layers may instruct the UE not to send a PSFCH containing HARQ-ACK information corresponding to receiving a PSSCH.

[0152] The UE provides HARQ-ACK information in a PSFCH transmission from a resource pool when the UE receives a PSSCH from a resource pool and the HARQ Feedback Enable / Disable Indicator field of the associated SCI format 2-A / 2-B / 2-C has a value of 1. The UE transmits the PSFCH in the first slot of the resource pool that includes PSFCH resources and corresponds to at least the number of slots provided by sl-MinTimeGapPSFCH after the last slot of PSSCH reception.

[0153] sl-PSFCH-RB-Set can be used to provide the UE with M in the resource pool PRB,set PSFCH A set of PRBs for PSFCH transmission including HARQ-ACK information in the physical resource blocks (PRBs) of the resource pool. The UE can be provided with M in the resource pool through sl-RB-SetPSFCH. PRB,set PSFCHA set of N PRBs for PSFCH transmission including contention information in the PRBs of the resource pool. The UE expects different PRBs to be (pre-)set for contention information and HARQ-ACK information. For the resource pool N provided by sl-NumSubchannel SUBCH The number of subchannels and the number of PSSCH time slots associated with the PSFCH time slot is less than or equal to N PSSCH PSFCH , the UE receives M of the PSFCH slots and PSSCH slots associated with subchannel j to slot i PRB,set PSFCH PRBs are allocated [(i+jN PSSCH PSFCH ) M subch,slot' PSFCH (i+1+j N PSSCH PSFCH ) M subch,slot PSFCH -1] PRB. Here, M subch,slot PSFCH =M PRB,set PSFCH / (N subch N PSSCH PSFCH ), 0≤i <N PSSCH PSFCH , 0≤j <N subch , and the allocation starts in ascending order from i and continues in ascending order from j. PRB,set PSFCH YesN subch ·N PSSCH PSFCH multiples of.

[0154] The UE determines the number of PSFCH resources used for HARQ-ACK or contention information in the multiplexed PSFCH transmission based on the indication of sl-PSFCH-CandidateResourceType as R PRB,CS PSFCH =N type PSFCH ·M subch,slot PSFCH ·N CS PSFCH , where N CS PSFCH The number of cyclic shift pairs in the resource pool provided for sl-NumMuxCS-Pair.

[0155] - When sl-PSFCH-CandidateResourceType is set to startSubCH, N type PSFCH=1, and M subch,slot PSFCH PRBs are associated with the starting subchannel of the corresponding PSSCH.

[0156] - When sl-PSFCH-CandidateResourceType is set to allocSubCH, N type PSFCH =N subch PSSCH , and N subch PSSCH ·M subch,slot PSFCH PRBs and corresponding PSSCH N subch PSSCH sub-channels are associated.

[0157] - For conflicting information, determine the corresponding PSSCH based on sl-PSFCH-Occasion.

[0158] PSFCH resources are firstly type PSFCH ·M subch,slot PSFCH The PRBs are indexed in ascending order starting with N PRBs and then CS PSFCH The cyclic shift pairs are indexed starting with the cyclic shift pair in ascending order of the cyclic shift pair indices.

[0159] The UE determines the index of the PSFCH resource (corresponding to the reserved resource) for transmitting the PSFCH including the HARQ-ACK information or the contention information in response to the PSSCH reception as (P ID +M ID )mod RPRB,CS PSFCH Here, PID is the physical layer source identifier provided by SCI format 2-A / 2-B / 2-C that schedules PSSCH reception or SCI format 2-A / 2-B / 2-C that reserves resources for conflict information provided by other UEs. For HARQ-ACK information, if the UE detects SCI format 2-A with a broadcast type indicator field value of "01", M ID The identifier of the UE receiving the PSSCH indicated by the upper layer, otherwise M ID is 0. For conflicting information, M ID is 0.

[0160] For PSFCH transmissions including HARQ-ACK information or contention information, the UE uses the following Table 6 to obtain the cyclic shift pair index corresponding to the PSFCH resource index and the N CS PSFCHThe value m0 is determined to calculate the value α of the cyclic shift.

[0161] Table 6 illustrates a set of cyclic shift pairs.

[0162]

Table 6

[0163]

[0164] For PSFCH transmission including HARQ-ACK information, if the UE detects SCI format 2-A or SCI format 2-C with a broadcast type indicator field value of "01" or "10", the UE determines m as shown in Table 7 below. cs The value is used to calculate the value of the cyclic shift α, and if the UE detects SCI format 2-B or 2-A with a broadcast type indicator field value of "11", the UE determines m as shown in the following Table 8 cs For PSFCH transmission including collision information, the UE determines m as shown in Table 9 below cs The UE applies one cyclic shift from the cyclic shift pair to the sequence for PSFCH transmission. Table 7 illustrates the mapping of the cyclic shift of the sequence for PSFCH transmission from the cyclic shift pair to the HARQ-ACK information bit value when the HARQ-ACK information includes ACK or NACK.

[0165]

Table 7

[0166]

[0167] Table 8 illustrates the mapping of sequences from cyclic shift pairs for PSFCH transmission and HARQ-ACK information bit values ​​when the HARQ-ACK information contains only NACK.

[0168]

Table 8

[0169]

[0170] Table 9 illustrates the mapping of cyclic shifts of a sequence used for PSFCH transmission and conflicting information bit values ​​from cyclic shift pairs.

[0171]

Table 9

[0172]

[0173] Figure 8 The diagram illustrates broadcast types used for V2X or SL communication in a wireless communication system to which the present disclosure can be applied. Figure 8 The embodiments of can be combined with various embodiments of the present disclosure. Figure 8 , Figure 8 (a) indicates broadcast type SL communication, Figure 8 (b) represents unicast type SL communication, and Figure 8 (c) represents a multicast type SL communication. In the case of a unicast type SL communication, a UE is able to perform one-to-one communication with another UE. In the case of a multicast type SL communication, a UE can perform SL communication with one or more UEs in the group to which it belongs. In various embodiments of the present disclosure, SL groupcast communication may be referred to as SL multicast communication, SL one-to-many communication, etc.

[0174] Hereinafter, a HARQ (Hybrid Automatic Repeat Request) process will be described.

[0175] For example, SL HARQ feedback may be enabled for unicast. In this case, in non-code block group (CBG) operation, if the receiving UE decodes the PSCCH for the receiving UE and the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE may generate an ACK. The receiving UE may then send the HARQ-ACK to the transmitting UE. On the other hand, if the receiving UE fails to successfully decode the transport block associated with the PSCCH after decoding the PSCCH for the receiving UE, the receiving UE may generate a NACK. The receiving UE may then send the NACK to the transmitting UE.

[0176] In addition, for example, SL HARQ feedback may be enabled for multicast. For example, in non-CBG operation, two HARQ feedback options may be supported for multicast.

[0177] (1) Multicast Option 1: If the receiving UE fails to decode the transport block associated with the PSCCH after decoding the PSCCH for the receiving UE, the receiving UE may send a NACK to the transmitting UE via the PSFCH. On the other hand, if the receiving UE decodes the PSCCH for the receiving UE and the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE may not send an ACK to the transmitting UE.

[0178] (2) Multicast Option 2: If the receiving UE fails to decode the transport block associated with the PSCCH after decoding the PSCCH for the receiving UE, the receiving UE may send a NACK to the transmitting UE via the PSFCH. Then, if the receiving UE decodes the PSCCH for the receiving UE and the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE may send an ACK to the transmitting UE via the PSFCH.

[0179] For example, if multicast option 1 is used for SL HARQ feedback, all UEs performing multicast communication may share PSFCH resources. For example, UEs belonging to the same group may use the same PSFCH resources to send HARQ feedback.

[0180] For example, if multicast option 2 is used for SL HARQ feedback, each UE performing multicast communication may use different PSFCH resources for HARQ feedback transmission. For example, UEs belonging to the same group may use different PSFCH resources to send HARQ feedback.

[0181] In the present disclosure, ACK may be referred to as HARQ-ACK, ACK information, or positive ACK information, and NACK may be referred to as HARQ-NACK, NACK information, or negative ACK information.

[0182] The sidelink grant may be semi-persistently configured by RRC or dynamically received on PDCCH, which is selected autonomously by the MAC entity. The MAC entity may have a sidelink grant on an active SL BWP to determine the set of PSCCH periods in which SCI transmissions occur and the set of PSSCH periods in which SL-SCH transmissions associated with SCI occur.

[0183] When the MAC entity is configured for sidelink resource allocation mode 1, the MAC entity may perform actions based on each PDCCH opportunity and each grant received for that PDCCH opportunity.

[0184] UE / base station behavior for consistent LBT failure in SL transmission

[0185] NR Unlicensed (NR-U) refers to a mode that provides cellular operators with the necessary technology to integrate unlicensed spectrum into their wireless communication systems. NR-U can enable both uplink and downlink operations in unlicensed spectrum.

[0186] In NR-U, channel access to uplink and downlink relies on LBT functionality. The UE and / or base station may first sense the communication channel to determine if there is no communication before transmission. If the communication channel is a broadband unlicensed carrier, the channel sensing process of NR-U may rely on sensing the energy levels in multiple subbands of the communication channel. The base station may configure LBT parameters (e.g., type / duration, clear channel assessment parameters, etc.) for the UE.

[0187] In NR-U, the UE can determine the time and location of transmission and reception based on the indication of the COT (channel occupancy time) structure. The COT consists of multiple time slots, and each time slot can consist of downlink resources, uplink resources, or flexible resources.

[0188] In the NR-U system, both continuous and interleaved uplink resource allocation can be supported while complying with the rules. In interleaved uplink resource allocation, the basic unit of resource allocation for the NR unlicensed channel can be an interlace. For example, a single interlace can consist of ten equidistant resource blocks within a 20MHz frequency bandwidth with a 15kHz subcarrier spacing.

[0189] For NR-U, the physical layer may perform an LBT process. The LBT process means a process in which transmission is not performed when it is determined that the channel is occupied. If the channel is identified as occupied according to the LBT process, the physical layer may not perform transmission. If the physical layer performs an LBT process before transmission and does not perform transmission, the physical layer may send an LBT failure indication to the MAC entity.

[0190] Unless otherwise specified, when performing an LBT procedure for a transmission, the operations specified in this disclosure may be performed regardless of whether an LBT failure indication is received from the physical layer. If the physical layer does not perform LBT, an LBT failure indication may not be received from the physical layer. An SR (scheduling request) may be triggered by an LBT (listen before talk) failure in a UL transmission.

[0191] SR (Scheduling Request) can be triggered by LBT (Listen Before Talk) failure in UL transmission.

[0192] Here, the MAC entity can:

[0193] 1> If the triggering of a consistent LBT in SpCell fails and is not cancelled; and

[0194] 1> If UL-SCH resources are available for new transmissions in the SpCell and as a result of logical channel priority, these UL-SCH resources are able to accommodate the LBT Failure MAC CE and its subheaders:

[0195] 2> Indicates the multiplexing and assembly process to generate the LBT failure MAC CE.

[0196] 1> If the triggering of consistent LBT fails in at least one SCell and is not cancelled:

[0197] 2> If UL-SCH resources are available for new transmissions in the serving cell where a consistent LBT failure is not triggered, and as a result of logical channel priority, these UL-SCH resources are able to accommodate the LBT failure MAC CE and its subheader:

[0198] 3> Indicates that the multiplexing and assembly process to generate LBT failed MAC CE

[0199] 2> Otherwise:

[0200] 3> Trigger scheduling request for LBT failed MAC CE.

[0201] When SL transmission is supported in an unlicensed band, the UE can perform LBT on the SL transmission. Here, LBT failure can occur not only in UL transmission but also in SL transmission. Therefore, when SL mode 1 is configured, the gNB may need to know whether LBT failure occurs for SL transmission. However, there is a problem that the basic wireless communication system does not support LBT failure reporting for SL transmission.

[0202] Hereinafter, a method in which a UE reports an LBT failure to a base station when a consistent LBT failure occurs for SL transmission in an unlicensed band is described.

[0203] exist Fig. 9 In the present invention, for convenience of explanation, the sidelink Tx (transmitting) UE is referred to as the first UE, and the sidelink Rx (receiving) UE is referred to as the second UE. Fig. 9 In the embodiment, the sidelink operation between the first UE and the second UE can be operated in an unlicensed band / spectrum or a shared spectrum.

[0204] Fig. 9 is a diagram for explaining a process in which a first UE performs communication according to one embodiment of the present disclosure.

[0205] A first user equipment (UE) may receive configuration information related to at least one resource block (RB) set for side link (SL) transmission from a base station (S910).

[0206] For example, the configuration information associated with at least one RB set may include the number of RBs in at least one resource pool (configured by the base station), the lowest RB index of the lowest index subchannel in the resource pool, the number of RBs in each RB set, etc.

[0207] Additionally or alternatively, the first UE may receive configuration information related to the SL resource allocation mode, configuration information related to one or more SL resource pools, configuration information related to the SL RLC bearer, etc. from the base station.

[0208] For example, the configuration information sent to the first UE may be included in upper layer signaling (eg, RRC, SIB, etc.).

[0209] Based on detecting a consistent SL LBT failure for a specific RB set within the at least one RB set, the first UE may send a MAC CE related to the consistent SL LBT failure to the base station ( S920 ).

[0210] Additionally or alternatively, based on detecting a consistent SL LBT failure for a specific resource pool among at least one resource pool, the first UE may send a MAC CE related to the consistent SL LBT failure to the base station.

[0211] Specifically, the first UE may detect / trigger an LBT failure for a specific RB set or a specific resource pool among at least one resource pool / RB set. Therefore, the first UE may report a (SL LBT failure) MAC CE to the base station. The (SL LBT failure) MAC CE may include information indicating that a consistent SL LBT failure has been detected for a specific RB set / specific resource pool.

[0212] Additionally or alternatively, the (SL LBT Failure) MAC CE may include information indicating at least one of a cell or a SL BWP in which a consistent SL LBT failure is detected.

[0213] For example, the first UE may send information to the base station for a separate SL LBT failure report for the RB set, SLBWP, resource pool or / and cell where a (consistent) SL LBT failure occurs. Each of the LBT failure MAC CE in the uplink and the new SLLBT failure MAC CE may be distinguished by a different LCID value in the subheader of the MAC PDU containing the corresponding MAC CE.

[0214] That is, the LCID of the subheader corresponding to the MAC PDU including the MAC CE associated with the consistent SL LBT failure may have a different LCID value from the subheader corresponding to the MAC PDU including the MAC CE associated with the LBT failure in the uplink.

[0215] The SL LBT failure reported to the base station may be associated with the SR resource. For example, if N or more SL LBT failures are detected, the first UE may report this to the base station.

[0216] Additionally or alternatively, upon detecting SL LBT failure, the first UE may trigger an LBT failure MAC CE reporting UL LBT failure. At this time, the LBT failure MAC CE may report the LBT failure of the cell where the UL or SL LBT failure occurs (regardless of SL or UL).

[0217] Additionally or alternatively, based on detecting a consistent SL LBT failure for a particular RB set among at least one RB set, the first UE may send a physical uplink control channel (PUCCH) to the base station, which includes SL HARQ-ACK information indicating a negative acknowledgement (NACK) and information indicating that the NACK is generated / caused by the consistent SL LBT.

[0218] Here, based on the SL resource allocation mode 1 configured for the first UE, the first UE may send a PUCCH to the base station, which includes a NACK and information indicating that the NACK is generated / caused by a consistent SL LBT. Here, the NACK may be for a specific TB. That is, the first UE may report the SL HARQ-ACK to the base station via the PUCCH only for a specific TB.

[0219] PUCCH with SL HARQ-HARQ may include information indicating whether the reported NACK is caused by LBT failure (i.e., information indicating whether PUSCCH transmission is not performed due to LBT failure), and / or information indicating N consecutive LBT failures detected for SL transmission.

[0220] For example, based on the collision of PUCCH and SL transmission, the first UE may discard SL transmission and send PUCCH to the base station. Then, based on the SR (scheduling request) to the triggered MAC CE, the first UE may send the PUCCH allocated for SR to the base station.

[0221] Additionally or alternatively, the UE may receive an RRC (Radio Resource Control) reconfiguration message from the base station to configure a new RB set / resource pool. Thus, the first UE may change the RB set / resource pool used for SL communication from a specific RB set / specific resource pool to a new RB set / new resource pool.

[0222] Additionally or alternatively, upon receiving a DCI (e.g., DCI format 3_x (where x is an integer greater than or equal to 0)) and / or a MAC CE indicating a new RB set / new resource pool from the base station, the first UE may change the RB set / resource pool used for SL communication from a specific RB set / specific resource pool to a new RB set / specific resource pool.

[0223] Additionally or alternatively, the first UE may autonomously change the RB set / resource pool used for SL communication from a specific RB set / specific resource pool to a new RB set / new resource pool. For example, the first UE may change the RB set used for SL communication from a specific RB set to a default RB set configured by the base station, or to a SL RB set of an initial SL BWP associated with an initial UL BWP.

[0224] Fig. 9 The method performed by the first UE described in the example may be performed by Fig.13 The first device (100) executes.

[0225] For example, Fig.13The one or more processors (102) of the first device (100) may be configured to receive configuration information related to at least one RB set for SL transmission from a base station through one or more transceivers (106). The one or more processors (102) may be configured to send a MAC CE related to a consistent SL LBT failure to the base station through the one or more transceivers (106) based on detecting a consistent SL LBT failure for a specific RB set among the at least one RB set.

[0226] In addition, the one or more memories (104) of the first device (100) may store instructions for executing, when executed by the one or more processors (102), Fig. 9 The method described in the example.

[0227] Fig.10 is a diagram for explaining a process in which a base station performs communication according to one embodiment of the present disclosure.

[0228] The base station may transmit configuration information related to at least one resource block (RB) set for SL transmission to the first UE (S1010).

[0229] Already referenced Fig. 9 The configuration information transmitted from the base station to the first UE is described in detail, and thus any redundant description will be omitted.

[0230] Based on detecting a consistent SL LBT failure for a specific RB set among the at least one RB set, the base station may receive a MAC CE related to the consistent SL LBT failure from the first UE ( S1020 ).

[0231] Additionally or alternatively, based on detecting a consistent SL LBT failure for a specific resource pool within the at least one resource pool, the base station may receive a MAC CE related to the consistent SL LBT failure from the first terminal.

[0232] The base station can detect / trigger SL LBT failure for a specific RB set / specific resource pool through a MAC CE associated with a consistent SL LBT failure. The base station can send an RRC reconfiguration message / DCI / DL MAC CE to the first UE so that the first UE can perform SL communication by changing from a specific RB set / specific resource pool to a new RB set / new resource pool.

[0233] Fig.10 The method performed by the base station described in the example can be performed by Fig.13 The second device (200) executes.

[0234] For example, Fig.13The one or more processors (202) of the second device (200) may be configured to send configuration information related to at least one resource block (RB) set for SL transmission to the first terminal via one or more transceivers (206). The one or more processors (202) may be configured to receive a MAC CE related to a consistent SL LBT failure from the first terminal via the one or more transceivers (206) based on the detection of a consistent SL LBT failure of a specific RB set among the at least one RB set.

[0235] In addition, the one or more memories (204) of the second device (200) may store instructions for executing when executed by the one or more processors (202) Fig.10 The method described in the example.

[0236] Fig.11 is a diagram illustrating a method for reporting consistent SL LBT failure according to one embodiment of the present disclosure.

[0237] Fig.11 The examples are for the convenience of explanation and do not limit the scope of the present disclosure. Fig.11 Some of the steps illustrated in the figure may be omitted depending on the situation and / or setting. Fig.11 The Tx terminal / Rx terminal / base station 11 in the figure is only an example and can be used as follows Fig.13 The device implementation shown in the figure.

[0238] For example, Fig.13 The processor (102 / 202) can control to use the transceiver (106 / 206) to send and receive channels / signals / data / information, etc. In addition, Fig.13 The processor (102 / 202) can control to store the channel / signal / data / information etc. to be transmitted in the memory (104 / 204), and can also control to store the channel / signal / data / information etc. received in the memory (104 / 204).

[0239] The base station may send configuration information to the transmitting UE via an RRC message (S1010). Here, the configuration information may include information related to PUCCH resources for (SL) LBT failure, information related to SL resource allocation mode, and / or information related to SL resource pool.

[0240] For sidelink resource allocation mode 2, the transmitting UE may reserve sidelink resources (S1020). The transmitting UE may perform sidelink transmission using the reserved resources.

[0241] In case of sidelink resource allocation mode 1, the transmitting UE may monitor the PDCCH (S1030). If a DCI of a CRC scrambled by the SL-RNTI or SLCS-RNTI is received from the base station through the PDCCH, the transmitting UE may allocate sidelink resources according to the DCI. The transmitting UE may perform SL transmission using one of the resources received in the SL BWP of the cell. The transmitting UE may perform UL transmission on the UL BWP of the same cell. The SL BWP and the UL BWP may overlap in frequency but not in time in the same cell.

[0242] That is, the transmitting UE may selectively perform the operation according to step S1020 and the operation according to step S1030 depending on the sidelink resource allocation mode.

[0243] For sidelink transmission in the unlicensed band, the physical layer (i.e., L1) of the transmitting UE may perform a channel access procedure. The transmitting UE may access the channel on which SL or UL transmission is performed according to a Type 1 or Type 2 UL channel access procedure. During the channel access procedure, if the physical layer of the transmitting terminal fails to access the channel before making an expected UL or SL transmission to the base station, the physical layer may notify the MAC layer of the channel access failure (i.e., LBT failure).

[0244] For SL (re)transmission of a TB on SL resources according to SL mode 1 (or SL mode 2), if the physical layer of the sending UE notifies the MAC layer that the LBT of the SL transmission of the TB has failed, and if the PUCCH resources are configured with SL mode 1, the sending UE can send "NACK" to the base station through PUCCH to report the SL HARQ-ACK information.

[0245] That is, if the transmitting UE fails to send SL (re)transmission of a TB, even if the UE does not receive SL HARQ feedback, it may send “NACK” to the base station via PUCCH using PUCCH resources allocated for reporting SL HARQ-ACK information.

[0246] The PUCCH resources may be associated with the SL resources used for SL transmission of the TB (eg, in terms of the HARQ process ID of the TB). The UCI of the PUCCH may indicate whether the reported NACK is caused by an LBT failure (ie, the PSSCH was not sent due to an LBT failure).

[0247] For example, two bits on PUCCH format 0 or PUCCH format 1 may respectively indicate: a first HARQ-ACK bit indicating a NACK and a second HARQ-ACK bit indicating that the reported NACK is caused by an LBT failure.

[0248] Additionally or alternatively, the transmitting UE may report the HARQ process ID (and the NDI value of the TB) and the NACK in the UCI of the PUCCH. The reported HARQ process ID may be the HARQ process ID used by the base station for scheduling SL resources (e.g., in the DCI) or the HARQ process ID indicated in the SCI for scheduling SL resources.

[0249] Additionally or alternatively, the PUCCH may include CG-UCI information including COT sharing that the base station may use.

[0250] Additionally or alternatively, if the sending UE fails to send a SL (re)transmission of a TB (e.g., because the maximum number of TBs has been reached) or if the sending UE fails to send a TB, then the sending UE may send a PUCCH to the base station by triggering an SR if the base station may configure dedicated SR PUCCH resources for this purpose.

[0251] Additionally or alternatively, if the transmitting terminal fails to send a SL (re)transmission of a TB with enabled SL HARQ feedback and the SL transmission of the TB fails due to LBT failure, the options described below may be applied.

[0252] Option 1: Transmitting The UE may not transmit the PUCCH allocated to report SL HARQ feedback to the TB. The base station may detect DTX in the PUCCH transmission. DTX may indicate no TX (ie, no transmission performed) due to LBT error.

[0253] Option 2: The transmitting UE may send NACK through the allocated PUCCH to report the SL HARQ feedback to the TB for SL transmission failure due to LBT failure.

[0254] Option 3: Transmitting UE may indicate "LBT Failure" on the PUCCH allocated to report SL HARQ feedback to the TB.

[0255] The sending UE may trigger a consistent LBT failure and trigger an SR by detecting an LBT failure ( S1040 ).

[0256] Specifically, RRC may establish a consistent LBT failure recovery procedure for the MAC entity of the sending UE. If the physical layer of the sending UE fails to access the channel before the UL or SL transmission expected by the base station, the physical layer may notify the MAC layer of the channel access failure (i.e., LBT failure). The sending UE may detect consistent LBT failure on a per SL BWP, per UL BWP, or per serving cell basis by counting LBT failure indications for all SL transmissions and / or all UL transmissions from the physical layer to the MAC entity based on one of the embodiments described below.

[0257] Hereinafter, unless otherwise specified, the term terminal may mean a transmitting terminal.

[0258] Example 1: Integrated UL / SL LBT failure detection and recovery process

[0259] The UE may count LBT_COUNTER based on LBT failures for both UL transmission via UL BWP and SL transmission via SL BWP for each serving cell. LBT failure MAC CE may be generated and shared for LBT failures in both UL and SL. SR (Scheduling Request) may be triggered and shared for LBT failures in both UL and SL. SR configuration and resources may be common for both UL LBT failure reporting and SL LBT failure reporting. Parameters of "lbt-FailureRecoveryConfig" (e.g., "lbt-FailureInstanceMaxCount" and "lbt-FailureDetectionTimer") may be shared between UL and SL and may be configured by RRC.

[0260] RRC can establish a consistent LBT failure recovery process for the MAC entity of the UE. Consistent LBT failure for each UL BWP, each SL BWP, or each BWP of overlapping UL BWP and SLBWP can be detected by counting LBT failure indications for all UL transmissions and / or all SL transmissions from the lower layer (i.e., physical layer) to the MAC entity.

[0261] LBT_COUNTER (per serving cell) can be used for consistent LBT failure detection process. LBT_COUNTER is a counter for LBT failure indications, which is initially set to 0. For each serving cell, LBT_COUNTER can be used to count only LBT failure indications for UL transmissions of the UL BWP of the serving cell, or only LBT failure indications for SL transmissions of the SL BWP of the serving cell, or both LBT failure indications for UL transmissions and LBT failure indications for SL transmissions of both UL BWP and SL BWP of the serving cell.

[0262] For each activated serving cell configured with "lbt-FailureRecoveryConfig", the UE's MAC entity may perform the following actions:

[0263] 1> If an LBT failure indication has been received from the lower layer:

[0264] 2> Start or restart lbt-FailureDetectionTimer;

[0265] 2> LBT_COUNTER is incremented by 1;

[0266] 2> If LBT_COUNTER >= lbt-FailureInstanceMaxCount:

[0267] 3>Consistent LBT failure of the active UL BWP on the serving cell is triggered;

[0268] 3>Consistent LBT failure of the active SL BWP on the triggering serving cell;

[0269] 3> If the serving cell is SpCell:

[0270] 4> If consistent LBT fails to be triggered on all UL BWPs set as PRACH opportunities on the same carrier of the serving cell; or

[0271] 4> If consistent LBT fails to be triggered on the corresponding SL BWP and PRACH opportunity is configured on the UL BWP of the same carrier as the SLBWP in the corresponding serving cell:

[0272] 5> Indicate consistent LBT failure to higher layers (ie, RRC layer).

[0273] 4> Otherwise:

[0274] 5> Stop the ongoing random access process on the serving cell;

[0275] 5> Switch the active UL BWP to the (target) UL BWP on the same carrier of the serving cell that is configured with a PRACH opportunity and has not triggered a consistent LBT failure;

[0276] 5> Switch the active SL BWP to a (target) SL BWP on the same carrier of the serving cell that is configured with a PRACH opportunity and has not triggered a consistent LBT failure, where the target SL BWP is associated with or overlaps the target UL BWP.

[0277] 5> Initiate random access process.

[0278] 1> If all triggered consistent LBT failures on the serving cell are cancelled; or

[0279] 1> If lbt-FailureDetectionTimer expires; or

[0280] 1> If lbt-FailureDetectionTimer or lbt-FailureInstanceMaxCount is reconfigured by higher layers:

[0281] 2> Set LBT_COUNTER to 0.

[0282] The UE's MAC entity shall:

[0283] 1> If the triggering of consistent LBT in SpCell fails and is not cancelled; and

[0284] 1> If UL-SCH resources are available for new transmissions in the SpCell and as a result of logical channel priority, the UL-SCH resources can accommodate the LBT failure MAC CE and its subheader:

[0285] 2> Indicates the multiplexing and assembly process to generate the LBT failure MAC CE.

[0286] 1> If the consistent LBT triggering fails on at least one SCell and is not cancelled:

[0287] 2> If UL-SCH resources are available for new transmissions in the serving cell where a consistent LBT failure has not been triggered and due to logical channel priority, the UL-SCH resources are able to accommodate the LBT failure MAC CE and its subheader:

[0288] 3> Indicates the multiplexing and assembly process to generate the LBT failure MAC CE.

[0289] 2> Otherwise:

[0290] 3>Trigger scheduling request for LBT failed MAC CE.

[0291] 1> When a MAC PDU has been sent and no LBT failure indication has been received from the lower layers and the PDU contains an LBT failure MAC CE:

[0292] 2> Cancel all consistent LBT failures triggered on the SCell indicated by the sent LBT failure MAC CE.

[0293] 1> If the triggering of a consistent LBT in SpCell fails and is not cancelled; and

[0294] 1> If the random access process is considered to have been successfully completed in SpCell:

[0295] 2> Cancel all consistent LBT errors triggered in SpCell.

[0296] 1> If the upper layer reconfigures lbt-FailureRecoveryConfig for the serving cell:

[0297] 2> Cancel all consistent LBT failures triggered on this serving cell.

[0298] Example 1-1

[0299] Embodiment 1-1 relates to the LBT failure MAC CE used in Embodiment 1.

[0300] An octet LBT Failure MAC CE can be identified by a MAC subheader with a specific LCID (e.g., an LCID mapped to index / codepoint 43 or / and 49). Fig.12 As illustrated in (a), the size of an octet LBT failure MACCE is fixed and may consist of a single octet including eight C fields.

[0301] The 4-octet LBT Failure MAC CE may be identified by a MAC subheader with a specific LCID (e.g., an LCID mapped to index / codepoint 42 or / and 48). Fig.12 As illustrated in (b), the size of the 4-octet LBT Failure MAC CE is fixed and may consist of 4 octets containing 32 C fields.

[0302] If the highest "ServCellIndex" of the serving cell of the MAC entity detecting the LBT failure is less than 8, the single octet format is used, otherwise the four octet format can be used.

[0303] If in Fig.12 If (a) and (b) exist, a serving cell is configured for the MAC entity with "ServCellIndex" i, and a consistent LBT failure is triggered across UL and SL and the consistent LBT failure on the serving cell is not canceled, Ci may be set to 1. Otherwise, Ci may be set to 0.

[0304] Example 2: SL-specific LBT failure detection and recovery process

[0305] That is, Embodiment 2 involves separate LBT failure detection and recovery procedures for SL LBT failure and UL LBT failure, and may involve interaction between SL LBT failure and UL LBT failure.

[0306] The UE may count an existing LBT_COUNTER based on LBT failure for UL transmission in UL BWP and a new LBT_COUNTER_SL based on LBT failure for SL transmission in SL BWP, respectively, for each serving cell.

[0307] The existing LBT failure MAC CE and the new LBT failure MAC CE may be generated separately for the LBT failure of UL and the LBT failure of SL, respectively. SR configuration and resources may be configured and allocated separately for the UL LBT failure and SL LBT failure reports.

[0308] Parameters of "lbt-FailureRecoveryConfig" (eg, "lbt-FailureInstanceMaxCount" and "lbt-FailureDetectionTimer") may be configured separately for UL LBT failure and SL LBT failure via RRC.

[0309] Additionally or alternatively, as embodiment 2, the existing LBT failure MAC CE may be reused for SL LBT failure reporting and UL LBT failure reporting. That is, the same MAC CE format may be used to indicate SL LBT failure or UL LBT failure based on different LC (Logical Channel) ID values.

[0310] Parameters in "lbt-FailureRecoveryConfig" (for example, "lbt-FailureInstanceMaxCount" and "lbt-FailureDetectionTimer") can be reused for SL LBT failure detection and UL LBT failure detection. That is, "lbt-FailureInstanceMaxCount" or "lbt-FailureDetectionTimer" can operate based on the configuration of the same corresponding parameter in "lbt-FailureRecoveryConfig".

[0311] Here, the SR configuration and resources may be common to both UL LBT failure reporting and SL LBT failure reporting.

[0312] Because the BWP can be composed of one or more RB sets (i.e., 20 MHz LBT bandwidth) on which the UE performs LBT, the UE can perform LBT failure detection and recovery procedures for SL or UL specific RB sets instead of SL BWP or UL BWP. In this case, the BWP can be replaced with an RB set in each embodiment.

[0313] The MAC entity of the UE may be configured with a consistent LBT failure recovery procedure by RRC. Consistent LBT failure of each UL BWP, each SL BWP, or each BWP of overlapping UL BWP and SL BWP may be detected by counting LBT failure indications for all UL transmissions or all SL transmissions from lower layers to the MAC entity.

[0314] RRC can configure the following parameters in "lbt-FailureRecoveryConfig" for UL LBT failure detection.

[0315] - lbt-FailureInstanceMaxCount for consistent LBT failure detection in UL

[0316] - lbt-FailureDetectionTimer for consistent LBT failure detection in UL

[0317] RRC can configure the following parameters in "lbt-FailureRecoveryConfigSL" to detect SL LBT failure.

[0318] - "lbt-FailureInstanceMaxCountSL" for consistent LBT failure detection in SL

[0319] - "lbt-FailureDetectionTimerSL" for consistent LBT error detection in SL

[0320] The following UE parameters may be used for a consistent LBT failure detection procedure for UL LBT failure.

[0321] - LBT_COUNTER (per serving cell): Counter of LBT failure indications, initially set to 0 for UL.

[0322] The following UE parameters may be used for a consistent LBT failure detection procedure for SL LBT failure.

[0323] - LBT_COUNTER_SL (per serving cell): Counter for LBT failure indications, initially set to 0 for SL.

[0324] For each activated serving cell set to "lbt-FailureRecoveryConfig", the UE's MAC entity may detect UL LBT failure:

[0325] 1> If an LBT failure indication for UL transmission is received from lower layers:

[0326] 2> Start or restart lbt-FailureDetectionTimer;

[0327] 2> LBT_COUNTER is incremented by 1;

[0328] 2> If LBT_COUNTER >= lbt-FailureInstanceMaxCount:

[0329] 3>Consistent LBT failure of the active UL BWP on the serving cell is triggered;

[0330] 3> If the serving cell is SpCell:

[0331] 4> If consistent LBT fails to be triggered in all UL BWPs configured as PRACH opportunities on the same carrier of the serving cell:

[0332] 5> Indicate consistent LBT failure to the upper layer (ie, RRC layer).

[0333] 4> Otherwise:

[0334] 5> Stop the ongoing random access process on the serving cell;

[0335] 5> Switch the active UL BWP to the (target) UL BWP configured with PRACH opportunities on the same carrier of the serving cell and without triggering a consistent LBT failure;

[0336] 5> Handover of the active SL BWP to a (target) SLBWP on the same carrier of the serving cell without triggering a consistent LBT failure, where the target SL BWP is associated with or overlaps the target UL BWP;

[0337] 5> Initiate random access process.

[0338] 1> Set LBT_COUNTER_SL to 0 if LBT fails for SL; or

[0339] 1> if all consistent LBT failures triggered in SL transmission are cancelled on the serving cell; or

[0340] 1> If lbt-FailureDetectionTimerSL expires; or

[0341] 1> If lbt-FailureDetectionTimerSL or lbt-FailureInstanceMaxCountSL is reconfigured by the upper layer; or

[0342] 1> If all consistent LBT failures triggered on the serving cell are cancelled; or

[0343] 1> If lbt-FailureDetectionTimer expires; or

[0344] 1> If lbt-FailureDetectionTimer or lbt-FailureInstanceMaxCount is reconfigured by the upper layer:

[0345] 2> Set LBT_COUNTER to 0.

[0346] For each activated serving cell configured with lbt-FailureRecoveryConfigSL, the UE's MAC entity can detect SL LBT failure.

[0347] 1> If an LBT failure indication for SL transmission is received from the lower layer:

[0348] 2> Start or restart lbt-FailureDetectionTimerSL;

[0349] 2> LBT_COUNTER_SL is incremented by 1;

[0350] 2> If LBT_COUNTER_SL >= lbt-FailureInstanceMaxCountSL:

[0351] 3> trigger consistent LBT failure for active SL BWP on the serving cell;

[0352] 3> If the serving cell is SpCell:

[0353] 4> If consistent LBT failure is triggered on all SL BWPs and PRACH triggering is configured on the UL BWP of the same carrier as the SL BWP in the serving cell:

[0354] 5> Indicate consistent LBT failure to the upper layer (i.e., RRC layer).

[0355] 4> Otherwise;

[0356] 5> Stop any random access process in progress in the serving cell;

[0357] 5> Switch the active SL BWP to the (target) SL BWP on the same carrier of the serving cell, where the UL BWP is configured with a PRACH opportunity and no consistent LBT failure is triggered in the UL or SL.

[0358] 5> Switching the active UL BWP to a (target) UL BWP on the same carrier of the serving cell, where a consistent LBT failure is not triggered, where the target UL BWP is associated with or overlaps the target SL BWP;

[0359] 5> Initiate random access process.

[0360] 1> if LBT_COUNTER is set to 0 for UL LBT failure; or

[0361] 1> If lbt-FailureDetectionTimer expires for UL LBT failure; or

[0362] 1> If lbt-FailureDetectionTimer or lbt-FailureInstanceMaxCount is reconfigured by the upper layer when UL LBT fails;

[0363] 1> if all consistent LBT failures triggered in UL transmissions are cancelled on the serving cell; or

[0364] 1> If all consistent LBT failures triggered in SL transmissions are cancelled on the serving cell; or

[0365] 1> If lbt-FailureDetectionTimerSL expires; or

[0366] 1> If lbt-FailureDetectionTimerSL or lbt-FailureInstanceMaxCountSL is reconfigured by the upper layer:

[0367] 2> Set LBT_COUNTER_SL to 0.

[0368] To report UL LBT failure, the MAC entity of the terminal can perform the following operations:

[0369] 1> If a consistent LBT failure is triggered in SpCell and is not cancelled for UL; and

[0370] 1> If UL-SCH resources in the SpCell are available for new transmissions and as a result of logical channel priority, these UL-SCH resources can accommodate the LBT failure MAC CE and its subheaders:

[0371] 2> Indicates the multiplexing and assembly process to generate the LBT failure MAC CE.

[0372] 1> If the triggering of consistent LBT on at least one SCell for UL fails and is not cancelled:

[0373] 2> If UL-SCH resources are available for new transmissions in the serving cell where a consistent LBT failure for UL or SL has not been triggered, and if as a result of logical channel priority, these UL-SCH resources can accommodate the LBT failure MAC CE and its subheader:

[0374] 3> Indicates the multiplexing and assembly process to generate the LBT failure MAC CE.

[0375] 2> Otherwise:

[0376] 3>Trigger scheduling request for LBT failed MAC CE.

[0377] 1> When a MAC PDU is transmitted and no LBT failure indication is received from lower layers and the PDU includes an LBT failure MAC CE:

[0378] 2> Cancel all consistent LBT failures triggered on the SCell, which indicates consistent LBT failures in the sent LBT Failure MAC CE.

[0379] 1> If triggering consistent LBT for UL fails and there is no cancellation in SpCell; and

[0380] 1> If the random access process in SpCell is considered to have been successfully completed:

[0381] 2> (Alt 1-1) Cancel all consistent LBT failures triggered on UL in SpCell except SL.

[0382] 2> (Alt 1-2) Cancel all consistent LBT failures triggered in SpCell on both UL and SL.

[0383] 1> If the upper layer of the serving cell reconfigures lbt-FailureRecoveryConfig:

[0384] 2> Cancel all consistent LBT failures triggered for UL on the serving cell.

[0385] 2> Cancel all consistent LBT failures triggered for SL on the serving cell.

[0386] To report SL LBT failure, the terminal's MAC entity can perform the following actions:

[0387] 1> If the triggering of a consistent LBT in SpCell for the SL fails and has not been cancelled; and

[0388] 1> If UL-SCH resources are available for new transmission in the SpCell and due to logical channel priority, the UL-SCH resources can accommodate the SL LBT Failure MAC CE and its subheader:

[0389] 2> Indicates that the multiplexing and assembly process to generate SL LBT failed MAC CE

[0390] 1> If a consistent LBT failure has been triggered for SL on at least one SCell and has not been canceled:

[0391] 2> if UL-SCH resources are available for new transmissions in the serving cell, where a consistent LBT failure has not been triggered for UL or SL, and due to logical channel priority, the UL-SCH resources can accommodate the SL LBT failure MAC CE and its subheader;

[0392] 3> Indicates the multiplexing and assembly process to generate the SL LBT failure MAC CE.

[0393] 2> Otherwise:

[0394] 3>Trigger scheduling request for SL LBT failed MAC CE.

[0395] 1> If a MAC PDU is sent and no SL LBT Failure indication is received from lower layers, and the PDU includes a SLLBT Failure MAC CE:

[0396] 2> Cancel all consistent LBT failures triggered on the SCell, which indicates consistent LBT failures in the sent LBT Failure MAC CE.

[0397] 1> If the consistent LBT trigger for SL fails and is not cancelled in SpCell; and

[0398] 1> If the random access process is considered to have been successfully completed in SpCell:

[0399] 2> (Alt 2-1) Cancel all consistent LBT failures triggered in SpCell for SLs other than UL.

[0400] 2> (Alt 2-2) Cancel all consistent LBT failures triggered in SpCell for both UL and SL.

[0401] 1> If the upper layer reconfigures lbt-FailureRecoveryConfigSL for the serving cell:

[0402] 2> Cancel all consistent LBT failures triggered for SL on the serving cell

[0403] 2> Cancel all consistent LBT failures triggered for UL on the serving cell

[0404] Example 2-1

[0405] Example 2-1 relates to the LBT failure MAC CE and SL LBT failure MAC CE used in Example 1.

[0406] An octet LBT Failure MAC CE and SL LBT Failure MAC CE may be identified by a MAC subheader with a specific LCID. Fig.12 As illustrated in (a), the size of an octet LBT Failure MAC CE is fixed and may consist of a single octet including eight C fields.

[0407] The 4-octet LBT Failure MAC CE and SL LBT Failure MAC CE can be identified by the MAC subheader with a specific LCID. Fig.12 As shown in (b), the size of the 4-octet LBT Failure MAC CE is fixed and can be composed of 4 octets including 32 C fields.

[0408] The UCID value of UL-SCH can be defined as shown in Table 10 below.

[0409]

Table 10

[0410]

[0411] If the highest "ServCellIndex" of the serving cell of the MAC entity detecting the LBT failure is less than 8, then the single octet format is used, otherwise the four octet format may be used. Fig.12 In (a) and (b), if there is a serving cell configured for the MAC entity with "ServCellIndex" i and a consistent LBT failure is triggered across UL and SL and the consistent LBT failure is not canceled in the serving cell, Ci may be set to 1. Otherwise, Ci may be set to 0.

[0412] Whether to use Embodiment 1 or Embodiment 2 may depend on the SL mode or the serving cell performing SL transmission. For example, Embodiment 1 may be used in SL mode 1, while Embodiment 2 may be used in SL mode 2. Embodiment 1 may be used in a serving cell that allows both UL and SL transmissions, while Embodiment 2 may be used in a serving cell. In this case, only SL transmission may be allowed, while UL transmission may not be allowed.

[0413] When the UE triggers a scheduling request for an LBT failure MAC CE or an SL LBT failure MAC CE according to one of the above embodiments, the UE may send a PUCCH allocated for SR or trigger a RACH.

[0414] Upon receiving an SR or RACH transmission, the base station may allocate an UL grant, i.e., a UL-SCH resource, to the UE. If the UL-SCH resource is available for new transmission of the SpCell and the UL-SCH resource is able to accommodate the corresponding subheader as a result of the LBT failure MAC CE or SL LBT failure MAC CE and the logical channel priority, the UE may instruct the multiplexing and assembly process to generate the LBT failure MAC CE or SL LBT failure MAC CE, as described in one of the above embodiments.

[0415] Therefore, the UE can use the UL-SCH resources to send LBT failure MAC CE or SL LBT failure MAC CE to the base station in UL.

[0416] When receiving the SR and / or MAC CE, the base station may execute one of the following alternatives.

[0417] Alternative A: An existing SL resource pool that detects consecutive LBT failures can be replaced with a new SL resource pool for SL transmission.

[0418] For example, the previous SL resource pool that reported the LBT failure in the aforementioned steps may be changed to a new SL resource pool in the RRC reset.

[0419] Additionally or alternatively, the base station may indicate a new SL resource pool via DCI format 3_0, DCI format 3_x, or DL ​​MAC CE. The UE receiving the indication may change the existing SL resource pool to the new SL resource pool.

[0420] Here, DCI format 3_0 or DCI format 3_x may include a SL resource pool index set for a new SL resource pool. Different SL resource pools of a cell may be configured with different SL resource pool indexes specific to the cell or UE.

[0421] Additionally or alternatively, the UE may autonomously change the old SL resource pool to the new SL resource pool just after SR, RACH transmission, or MAC CE transmission or just after detecting consecutive LBT failures.

[0422] The new SL resource pool may be a default SL resource pool configured by the base station or a SL resource pool of an initial SL BWP associated with an initial UL BWP.

[0423] Alternative B: An existing SL BWP that detects consecutive LBT failures may be changed to a new SLBWP for SL transport.

[0424] For example, the previous SL BWP that reported the LBT failure in the above steps may be changed to a new SL BWP in the RRC reconfiguration.

[0425] Additionally or alternatively, the base station may indicate a new SLBWP via DCI format 3_0, DCI format 3_x, or DL ​​MAC CE. The terminal receiving the indication may change the previous SL BWP to the new SL BWP.

[0426] DCI format 3_0 or 3_x may include a SL BWP indicator set for a new SL BWP. Different SLBWPs in a cell may be configured with different SL BWP indicator values ​​specific to the cell or UE.

[0427] Additionally or alternatively, the UE may autonomously change the previous SL BWP to a new SL BWP just after SR, RACH transmission, or MAC CE transmission or just after detecting consecutive LBT failures.

[0428] Here, the new SL BWP may be a default SL BWP configured by the base station or a SLBWP linked to the initial UL BWP.

[0429] Alternative C: An existing RB set where consecutive LBT failures are detected may be changed to a new RB set for SL transmission.

[0430] For example, the previous SL RB set reporting LBT failure in the aforementioned steps may be changed to a new SL RB set in RRC reconfiguration.

[0431] Additionally or alternatively, the base station may indicate a new SL RB set via DCI format 3_0, DCI format 3_x, or DL ​​MAC CE. The terminal receiving the indication may change the previous SL RB set to the new SL RB set.

[0432] DCI format 3_0 or DCI format 3_x may include an RB set index configured for a new SL RB set. Different RB sets of a cell may be configured with different RB set indexes specific to the cell or UE.

[0433] Additionally or alternatively, the UE may autonomously change a previous SL RB set to a new SL RB set just after SR, RACH transmission, or MAC CE transmission or just after detecting consecutive LBT failures.

[0434] The new SL RB set may be a default SL RB set configured by the base station, or a SL RB set of an initial SL BWP associated with an initial UL BWP.

[0435] Alternative D: An existing cell that detects consecutive LBT failures for SL transmissions may be changed to a new cell.

[0436] For example, the previous cell reporting the LBT failure in the aforementioned steps may be changed to a new cell in the RRC reconfiguration.

[0437] Additionally or alternatively, the base station may indicate the new cell via DCI format 3_0, DCI format 3_x, or DL ​​MAC CE. The terminal receiving the indication may change the existing cell to the new cell.

[0438] DCI format 3_0 or 3_x may include a cell index set for a new cell.

[0439] Additionally or alternatively, the UE may autonomously change the existing cell to a new cell just after SR, RACH transmission or MAC CE transmission or just after detecting consecutive LBT failures. Here, the new cell may be a default cell configured by the base station or a cell of the initial SL BWP associated with the initial UL BWP.

[0440] In the above alternatives, "lbt-FailureInstanceMaxCount" for consistent LBT failure detection may be configured with different values ​​for different alternatives.

[0441] Additionally or alternatively, the "lbt-FailureDetectionTimer" for consistent LBT failure detection may be configured with different values ​​for different alternatives.

[0442] For example, the base station may configure different "lbt-FailureInstanceMaxCount" values ​​for different alternatives. For example, the "lbt-FailureInstanceMaxCount" value of alternative A may be lower than the "lbt-FailureInstanceMaxCount" value of alternative B.

[0443] Alternatively, the base station may configure different “lbt-FailureDetectionTimer” values ​​for different alternatives, such that the “lbt-FailureDetectionTimer” value of alternative D may be lower than the “lbt-FailureDetectionTimer” value of alternative B.

[0444] 'lbt-FailureInstanceMaxCount' for consistent LBT failure detection and 'lbt-FailureDetectionTimer' for consistent LBT failure detection may be configured with different values ​​for SL mode 1 (ie, SL resource allocation mode 1) and SL mode 2 (ie, SL resource allocation mode 2), respectively.

[0445] For SL Mode 1, the above parameters may be used for SR reporting. For SL Mode 2, the above parameters may be used for resource reselection. Additionally or alternatively, SR may be triggered due to consistent LBT errors in the above steps for both SL Mode 1 and SL Mode 2.

[0446] The UE may detect a collision between PUCCH transmission for a triggered SR and a sidelink transmission ( S1050 ).

[0447] If the following conditions are met, the UE may prioritize PUCCH transmission of SR over sidelink transmission ( S1060 ).

[0448] - if the PUCCH resources used for the SR transmission do not overlap with the PUSCH duration of the uplink grant received in the random access response or the MSGA payload; and

[0449] - if the physical layer can signal the SR on a valid PUCCH resource for SR; and

[0450] - If the SL-SCH resources overlap with the PUCCH resources used for the SR transmission opportunity for the pending SR triggered by the LBT Failure MAC CE or SL LBT Failure MAC CE, and the MAC entity cannot perform the SR transmission simultaneously with the transmission of the SL-SCH resources,

[0451] The UE may prioritize PUCCH transmissions for SR over sidelink transmissions according to the method described below.

[0452] - When consistent LBT failure is triggered for UL and SL LBT failure on a first cell / carrier and a sidelink transmission occurs on a second cell / carrier, the UE may prioritize PUCCH transmission for SR over the sidelink transmission.

[0453] - When consistent LBT failure is triggered for UL LBT failure on a first cell / carrier and sidelink transmission occurs on the first cell / carrier, the UE may prioritize PUCCH transmission for SR over sidelink transmission.

[0454] - When consistent LBT failure is triggered for SL LBT failure on a first cell / carrier and sidelink transmission occurs on the first cell / carrier, the UE may prioritize PUCCH transmission for SR over sidelink transmission.

[0455] Additionally or alternatively, the base station may indicate to the UE whether an SR triggered for an LBT failure may take precedence over a sidelink transmission.

[0456] If an SR is not triggered for LBT failure MAC CE or SL LBT failure MAC CE, the UE may lower the priority of PUCCH transmission for other SRs over sidelink transmission.

[0457] If the UE prioritizes PUCCH transmission for SR over sidelink transmission, the UE may discard the sidelink transmission. Also, if the sidelink transmission does not conflict with any SR, the UE may perform the sidelink transmission using the reserved resources or the received resources.

[0458] like Fig.10 As illustrated in , when the UE performs SR PUCCH transmission to the base station at step S1070 , the base station may send a CRC-scrambled PDCCH with a C-RNTI for a UL grant to the UE, and the UE may send a (SL) LBT Failure MAC CE to the base station.

[0459] The base station may send a PDCCH including a new cell index, an SL BWP indicator, etc. to the UE as described above (S1075). The UE may change the SL BWP or cell based on the PDCCH (S1080). The base station may send a PDCCH CRC scrambled by the SL-RNTI or SLCS-RNTI to the terminal (S1085). The UE may perform PSCCH / PSCCH transmission with the receiving UE based on the PDCCH (S1090).

[0460] Additionally or alternatively, the UE may prioritize the PUSCH carrying the LBT Failure MAC CE or the SL LBT Failure MAC CE in the logical channel prioritization of the MAC entity for sending the MAC CE in a MAC PDU in the uplink, as described below.

[0461] - LBT Failure MAC CE for UL LBT Failure reporting may have a higher priority than SLLBT Failure MAC CE in logical channel prioritization as follows.

[0462] - In logical channel prioritization for UL-SCH transmission, logical channels may be prioritized in the following order. That is, the order listed first may have higher priority.

[0463] -- C-RNTI MAC CE or UL-CCCH data;

[0464] --Configured admission confirmation MAC CE or BFR MAC CE or multiple entries of configured admission confirmation MAC CE;

[0465] --MAC CE for sidelink setup grant confirmation;

[0466] --MAC CE for LBT failure;

[0467] --MAC CE for SL LBT failure (Example 1);

[0468] --MAC CE for timing advance reporting;

[0469] --MAC CE for SL LBT failure (Example 2);

[0470] - MAC CE of SL-BSR prioritized based on predefined criteria;

[0471] -- MAC CE of BSR, excluding BSR included for padding;

[0472] - Single-entry PHR MAC CE or multiple-entry PHR MAC CE;

[0473] - MAC CE of the number of symbols required to be protected;

[0474] - MAC CE of the preempted BSR;

[0475] - MAC CE of SL-BSRs, excluding SL-BSRs included for padding and SL-BSRs prioritized according to predefined criteria;

[0476] - Data of all logical channels, excluding UL-CCCH data

[0477] - MAC CE for recommended bit rate query;

[0478] - MAC CE of the BSR included for padding;

[0479] - MAC CE of the SL-BSR included for padding.

[0480] - The MAC entity may prioritize the transmission of NR sidelink communications in MAC CEs listed in an order higher than “data on all logical channels except data on UL-CCCH”.

[0481] The UE may prioritize the PUSCH carrying the MAC PDU containing the LBT Failure MAC CE or the SL LBT Failure MAC CE over the sidelink transmission.

[0482] In the above description, sidelink transmission, license and resources can be replaced by uplink transmission, license and resources. Specifically, when the base station allocates a SL license to a UE performing SL transmission in an unlicensed band, according to the present disclosure, the UE can report a consistent LBT failure of the SL transmission to the base station.

[0483] General equipment to which the present disclosure can be applied

[0484] Fig.13 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0485] refer to Fig.13 , the first wireless device 100 and the second wireless device 200 can send and receive wireless signals through a variety of radio access technologies (e.g., LTE, NR).

[0486] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in the present disclosure.

[0487] For example, the processor 102 may transmit a wireless signal including the first information / signal through the transceiver 106 after generating the first information / signal by processing the information in the memory 104. In addition, the processor 102 may receive a wireless signal including the second information / signal through the transceiver 106, and then store information obtained by signal processing of the second information / signal in the memory 104.

[0488] The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including commands for executing all or part of a process controlled by the processor 102 or for executing the description, function, process, proposal, method and / or operation flow chart disclosed in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver 106 may be connected to the processor 102 and may send and / or receive wireless signals through one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used in conjunction with an RF (radio frequency) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0489] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the description, function, process, proposal, method and / or operation flowchart disclosed in the present disclosure. For example, the processor 202 may generate third information / signal by processing the information in the memory 204, and then transmit the wireless signal including the third information / signal through the transceiver 206. In addition, the processor 202 may receive a wireless signal including fourth information / signal through the transceiver 206, and then store the information obtained by signal processing of the fourth information / signal in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including commands for executing all or part of the process controlled by the processor 202 or for executing the description, function, process, proposal, method and / or operation flowchart disclosed in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver 206 may be connected to the processor 202 and may send and / or receive wireless signals through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in conjunction with an RF unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0490] In the following, the hardware elements of the wireless device 100, 200 will be described in more detail. It is not limited thereto, and one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors 102, 202 may generate one or more PDUs (protocol data units) and / or one or more SDUs (service data units) according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts included in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in the present disclosure. One or more processors 102, 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, processes, proposals, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106, 206. The one or more processors 102, 202 may receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in the present disclosure.

[0491] One or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. In an example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102, 202. The description, functions, processes, proposals, methods, and / or operational flowcharts disclosed in the present disclosure may be implemented by using firmware or software and the firmware or software may be implemented to include modules, processes, functions, etc. Firmware or software configured to execute the description, functions, processes, proposals, methods, and / or operational flowcharts disclosed in the present disclosure may be included in one or more processors 102, 202 or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. The description, functions, processes, proposals, methods, and / or operational flowcharts disclosed in the present disclosure may be implemented by firmware or software in the form of codes, commands, and / or command sets.

[0492] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard drive, registers, cash memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located inside and / or outside one or more processors 102, 202. In addition, one or more memories 104, 204 may be connected to one or more processors 102, 202 via a variety of technologies such as wired or wireless connections.

[0493] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operation flow charts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc. mentioned in the description, function, process, proposal, method and / or operation flow chart, etc. disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may send and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to send user data, control information or wireless signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to send and receive user data, control information, wireless signals / channels, etc. mentioned in the description, functions, processes, proposals, methods and / or operation flow charts disclosed in the present disclosure through one or more antennas 108, 208. In the present invention, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received wireless signals / channels, etc. from RF band signals to baseband signals by using one or more processors 102, 202 to process received user data, control information, wireless signals / channels, etc. One or more transceivers 106, 206 may convert user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals to RF band signals. Therefore, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0494] The above-mentioned embodiments are elements and features of the present disclosure combined in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered optional. Each element or feature can be implemented in a form that is not combined with other elements or features. In addition, the embodiments of the present disclosure may include combined partial elements and / or features. The order of the operations described in the embodiments of the present disclosure may be changed. Some elements or features of an embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. It is clear that an embodiment may include a combined claim without an explicit dependency in the claim, or may be included as a new claim by modification after application.

[0495] It is clear to those skilled in the art that the present disclosure can be implemented in other specific forms within the scope of the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted restrictively in every aspect, but should be considered as illustrative. The scope of the present invention should be determined by the reasonable interpretation of the attached claims, and all changes within the equivalent scope of the present disclosure are included in the scope of the present invention.

[0496] The scope of the present disclosure includes software or machine executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations in a device or computer according to the methods of various embodiments, and non-transitory computer-readable media that store such software or commands, etc. and can be executed in a device or computer. Commands that can be used to program a processing system that performs the features described in the present disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product that includes such a storage medium. The storage medium may include a high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices located away from the processor. The memory or, alternatively, the non-volatile memory device in the memory includes a non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any machine-readable medium to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0497] Here, the wireless communication technology implemented in the wireless devices 100 and 200 of the present disclosure may include narrowband Internet of Things for low-power communication, as well as LTE, NR and 6G. Here, for example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, which may be implemented in standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above names. In addition or alternatively, the wireless communication technology implemented in the wireless devices 100 and 200 of the present disclosure may perform communication based on LTE-M technology. Here, in the example, LTE-M technology may be an example of LPWAN technology and may be referred to as various names such as eMTC (enhanced machine type communication). For example, LTE-M technology may be implemented in at least any one of the various standards including 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-bandwidth limited), 5) LTE-MTC, 6) LTE machine type communication, and / or 7) LTE M, etc., and is not limited to the above names. Additionally or alternatively, the wireless communication technology implemented in the wireless devices 100, 200 of the present disclosure may include at least any one of ZigBee, Bluetooth, and a low power wide area network (LPWAN) considering low power communication, and it is not limited to the above names. In an example, the ZigBee technology may generate a PAN (Personal Area Network) related to small / low power digital communication based on various standards such as IEEE 802.15.4, etc., and may be referred to as various names.

[0498] [Industrial Availability]

[0499] The method proposed in the present invention is mainly described by taking the application in 3GPP LTE / LTE-A and 5G systems as an example, but can also be applied to various wireless communication systems other than 3GPP LTE / LTE-A and 5G systems.

Claims

1. A method performed by a first user equipment (UE) in a wireless communication system, the method include: receiving, from a base station, configuration information associated with at least one resource block (RB) set for sidelink (SL) transmission; as well as based on detecting a consistent SL LBT (Listen Before Talk) failure for a specific RB set among the at least one RB set, sending a MAC (Media Access Control) CE (Control Element) related to the consistent SL LBT failure to the base station, The MAC CE includes information indicating that the consistent SL LBT failure is detected for the specific RB set.

2. The method according to claim 1, in: The MAC CE includes information indicating at least one of a cell or a SL BWP (bandwidth part) in which the consistent SL LBT failure is detected.

3. The method according to claim 1, in: A logical channel identification (LCID) corresponding to a subheader of a MAC PDU (Protocol Data Unit) including the MAC CE associated with the consistent SL LBT failure is different from an LCID value corresponding to a subheader of a MAC PDU including the MAC CE associated with the LBT failure in the uplink.

4. The method according to claim 1, in: Based on configuring SL resource allocation mode 1 for the UE: Based on detecting the consistent SL LBT failure for the specific RB set among at least one of the RB sets, a physical uplink control channel (PUCCH) is sent to the base station, and the PUCCH includes SLHARQ-ACK information indicating a negative acknowledgement (NACK) and information indicating that the NACK is generated by the consistent SL LBT.

5. The method according to claim 1, in: receiving an RRC (Radio Resource Control) reconfiguration message for configuring a new RB set from the base station, and The RB set used for SL communication is changed from the specific RB set to the new RB set by the first UE.

6. The method according to claim 1, in: Based on receiving DCI (Downlink Control Information) or a Downlink (DL) MAC CE indicating a new RB set from the base station, the RB set used for SL communication is changed from the specific RB set to the new RB set by the first UE.

7. The method according to claim 1, in: The RB set used for SL communication is changed, by the first UE, from the specific RB set to a default RB set configured by the base station or a SL RB set of an initial SL BWP associated with an initial UL BWP.

8. The method according to claim 4, in: Based on the collision of the PUCCH and SL transmissions, the SL transmission is dropped and the PUCCH is sent to the base station.

9. The method according to claim 1, in: Based on triggering a SR (Scheduling Request) for the MAC CE, a PUCCH allocated for the SR is transmitted to the base station.

10. A first user equipment (UE) in a wireless communication system, the first UE include: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: receiving, by the at least one transceiver, configuration information related to at least one resource block (RB) set for sidelink (SL) transmission from a base station; and Based on detecting a consistent SL LBT (Listen Before Talk) failure for a specific RB set among the at least one RB set, sending a MAC (Media Access Control) CE (Control Element) related to the consistent SL LBT failure to the base station through the at least one transceiver, The MAC CE includes information indicating that the consistent SL LBT failure is detected for the specific RB set.

11. A method performed by a base station in a wireless communication system, the method include: sending configuration information related to at least one resource block (RB) set for sidelink (SL) transmission to a first user equipment (UE); as well as receiving, based on detecting a consistent SL LBT (Listen Before Talk) failure for a specific RB set among at least one RB set, a MAC (Media Access Control) CE (Control Element) related to the consistent SL LBT failure from the first UE, The MAC CE includes information indicating that the consistent SL LBT failure is detected for the specific RB set.

12. A base station in wireless communication, the base station include: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: transmitting, by the at least one transceiver, to a first user equipment (UE), configuration information related to at least one resource block (RB) set for sidelink (SL) transmission; and receiving, based on detecting a consistent SL LBT (Listen Before Talk) failure for a specific RB set among at least one RB set, a MAC (Media Access Control) CE (Control Element) related to the consistent SL LBT failure from the first UE through the at least one transceiver, The MAC CE includes information indicating that the consistent SL LBT failure is detected for the specific RB set.

13. A processing device configured to control a first user equipment (UE) in a wireless communication system, the processing device include: at least one processor; as well as at least one computer memory operatively coupled to the at least one processor and storing instructions for performing operations when executed by the at least one processor; The operations include: receiving, from a base station, configuration information associated with at least one resource block (RB) set for sidelink (SL) transmission; and based on detecting a consistent SL LBT (Listen Before Talk) failure for a specific RB set among the at least one RB set, sending a MAC (Media Access Control) CE (Control Element) related to the consistent SL LBT failure to the base station, The MAC CE includes information indicating that the consistent SL LBT failure is detected for the specific RB set.

14. At least one non-transitory computer-readable medium storing at least one instruction, Based on the at least one instruction being executed by at least one processor, the device in the wireless communication system controls: receiving, from a base station, configuration information associated with at least one resource block (RB) set for sidelink (SL) transmission; and based on detecting a consistent SL LBT (Listen Before Talk) failure for a specific RB set among the at least one RB set, sending a MAC (Media Access Control) CE (Control Element) related to the consistent SL LBT failure to the base station, in, The MAC CE includes information indicating that the consistent SL LBT failure is detected for the specific RB set.

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