Method and apparatus for performing sidelink communication in wireless communication system

Abstract

A method and an apparatus for performing sidelink communication in a wireless communication system are disclosed. A method for a first terminal to perform sidelink communication according to an embodiment disclosed herein comprises the steps of: receiving DCI for allocating an SL grant from a base station, the DCI not including information indicating CAPC; and performing LBT for transmitting the specific TB using a first CAPC selected based on the specific TB corresponding to the SL grant, in which a first condition including only SL MAC CE based on the specific TB is satisfied, the first CAPC is a CAPC having the highest priority, and a second condition including SCCH based on the specific TB is satisfied, the first CAPC is a CAPC having the highest priority.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for performing sidelink 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 mobile communication system 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, a variety of technologies such as dual connectivity, massive multiple-input multiple-output (massive MIMO), in-band full-duplex, non-orthogonal multiple access (NOMA), ultra-wideband support, and device networking have been studied. Summary of the invention

[0004] Technical issues

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

[0006] The technical problem of the present disclosure is to provide a method and apparatus for configuring a transport block (TB) for side link resource transmission determined by a channel access method based on a channel access priority level (CAPC).

[0007] The technical problems to be achieved by the present disclosure are not limited to the above-mentioned technical problems, and those skilled in the art may clearly understand other technical problems not described herein through the following description.

[0008] Technical Solution

[0009] According to one embodiment of the present disclosure, a method for performing sidelink (SL) communication by a first user equipment (UE) in a wireless communication system may include receiving downlink control information (DCI) for allocating SL authorization from a base station, wherein the DCI does not include information indicating a channel access priority category (CAPC); and using a first CAPC selected based on a specific transport block (TB) corresponding to the SL authorization, performing listen-before-talk (LBT) for the transmission of a specific TB, and based on a first condition that the specific TB only includes an SL medium access control (MAC) control element (CE) is satisfied, the first CAPC may be a CAPC with the highest priority, and based on a second condition that the specific TB includes a sidelink control channel (SCCH) is satisfied, the first CAPC may be a CAPC with the highest priority sidelink control.

[0010] According to one embodiment of the present disclosure, a method for performing sidelink (SL) communication by a second user equipment (UE) in a wireless communication system may include receiving a physical sidelink shared channel (PSSCH) from a first UE, which includes a specific TB based on a first channel access priority category (CAPC) selected by a specific transport block (TB) corresponding to a SL authorization; and sending a physical sidelink feedback channel to the first UE, which includes hybrid automatic repeat request (HARQ)-acknowledgement (ACK) information for the PSSCH, and downlink control information (DCI) for allocating the SL authorization may be sent from a base station to the first UE, and the DCI does not include information indicating a channel access priority category (CAPC), and based on a first condition that the specific TB only includes an SL medium access control (MAC) control element (CE) is satisfied, the first CAPC may be a CAPC with the highest priority, and based on a second condition that the specific TB includes a sidelink control channel SCCH is satisfied, the first CAPC may be a CAPC with the highest priority.

[0011] Technical Effects

[0012] According to one embodiment of the present disclosure, a method and apparatus for performing sidelink communication in a wireless communication system may be provided.

[0013] As one embodiment of the present disclosure, a method and apparatus for configuring a transport block (TB) for side link resource transmission determined by a channel access method based on a channel access priority level (CAPC) may be provided.

[0014] 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

[0015] 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.

[0016] Figure 1 The structure of a wireless communication system to which the present disclosure can be applied is illustrated.

[0017] Figure 2 The frame structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0018] Figure 3 A resource grid in a wireless communication system to which the present disclosure can be applied is illustrated.

[0019] Figure 4 The physical resource blocks in a wireless communication system to which the present disclosure can be applied are illustrated.

[0020] Figure 5 The time slot structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0021] 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.

[0022] Figure 7 A process of performing V2X or SL communication according to a transmission mode in a wireless communication system to which the present disclosure can be applied is illustrated.

[0023] Figure 8 The broadcast types used for V2X or SL communication in a wireless communication system to which the present disclosure can be applied are illustrated.

[0024] Fig. 9 is a diagram for explaining a process in which a first UE performs communication according to an embodiment of the present disclosure.

[0025] Fig.10 It is a diagram for explaining a process in which a second UE performs communication according to an embodiment of the present disclosure.

[0026] Fig.11 is a diagram for explaining a signaling procedure of a base station, a first UE, and a second UE according to an embodiment of the present disclosure.

[0027] Fig.12 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description 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 know that the present disclosure can be implemented without these specific details.

[0029] 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 in the concepts of the present disclosure.

[0030] 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.

[0031] In the present disclosure, 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 elements, etc. 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.

[0032] 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 this disclosure has the same meaning as "and / or".

[0033] The present disclosure describes a wireless communication network or a wireless communication system, and operations performed in the wireless communication network can 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 can 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.

[0034] 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.

[0035] In the following, 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 part of a base station, and the receiver may be part of a terminal. In the uplink, the transmitter may be part of a terminal, and the receiver may be 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 can be fixed or mobile, and can 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.

[0036] The following description can be used for various radio access systems, such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, etc. CDMA can be implemented by UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA can be implemented by radio technologies such as GSM (Global System for Mobile Communications) / GPRS (General Packet Radio Service) / EDGE (Data Rate Enhanced GSM Evolution). OFDMA can 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.

[0037] 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 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. 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.

[0038] 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).

[0039] 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).

[0040] Abbreviations of terms that may be used in the present disclosure are defined as follows.

[0041] -BM: Beam Management

[0042] -CQI: Channel Quality Indicator

[0043] -CRI: Channel State Information-Reference Signal Resource Indicator

[0044] -CSI: Channel State Information

[0045] -CSI-IM: Channel State Information-Interference Measurement

[0046] -CSI-RS: Channel State Information-Reference Signal

[0047] -DMRS: Demodulation Reference Signal

[0048] -FDM: Frequency Division Multiplexing

[0049] -FFT: Fast Fourier Transform

[0050] -IFDMA: Interleaved Frequency Division Multiple Access

[0051] -IFFT: Inverse Fast Fourier Transform

[0052] -L1-RSRP: Layer 1 reference signal received power

[0053] -L1-RSRQ: Layer 1 reference signal reception quality

[0054] -MAC: Media Access Control

[0055] -NZP: Non-Zero Power

[0056] -OFDM: Orthogonal Frequency Division Multiplexing

[0057] -PDCCH: Physical Downlink Control Channel

[0058] -PDSCH: Physical Downlink Shared Channel

[0059] -PMI: Precoding Matrix Indicator

[0060] -RE: Resource Element

[0061] -RI: Rank Indicator

[0062] -RRC: Radio Resource Control

[0063] -RSSI: Received Signal Strength Indicator

[0064] -Rx: Receive

[0065] -QCL: Quasi-Co-located

[0066] -SINR: Signal to Interference and Noise Ratio

[0067] -SSB (or SS / PBCH block): synchronization signal block (including PSS (primary synchronization signal), SSS (secondary synchronization signal) and PBCH (physical broadcast channel))

[0068] -TDM: Time Division Multiplexing

[0069] -TRP: Transmit and Receive Point

[0070] -TRS: Tracking Reference Signal

[0071] -Tx: Send

[0072] -UE: User Equipment

[0073] -ZP: Zero Power

[0074] Overall system

[0075] 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.

[0076] 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, a cell may support multiple parameter sets. In other words, terminals operating according to different parameter sets may coexist in one cell.

[0077] 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.

[0078] Figure 1 The structure of a wireless communication system to which the present disclosure can be applied is illustrated.

[0079] Reference 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.

[0080] Figure 2 The frame structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0081] 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.

[0082] 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.

[0083] [Table 1]

[0084] μ <![CDATA[Δf=2 μ ·15[kHz]]]> CP 0 15 normal 1 30 normal 2 60 Normal, Extended 3 120 normal 4 240 normal

[0085] 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 of frequency ranges (FR1, FR2). FR1 and FR2 can be configured as shown in Table 2 below. In addition, FR2 can mean millimeter wave (mmW).

[0086] [Table 2]

[0087]

[0088]

[0089] 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 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 =1 ms duration. 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. 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.

[0090] [Table 3]

[0091] μ <![CDATA[N symb slot ]]> <![CDATA[N slot frame,μ ]]> <![CDATA[N slot subframe,μ ]]> 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

[0092] [Table 4]

[0093] μ <![CDATA[N symb slot ]]> <![CDATA[N slot frame,μ ]]> <![CDATA[N slot subframe,μ ]]> 2 12 40 4

[0094] Figure 2 is an example of μ=2 (SCS is 60kHz), see Table 3, 1 subframe can include 4 time slots. Figure 2 1 subframe = {1,2,4} shown in is an example, and the number of time slots that can be included in 1 subframe is defined as 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 can be applied is illustrated.

[0096] Reference Figure 3 , exemplarily describing 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 referencing 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 aliasing 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 ak,l'(p) or ak,l'. In addition, a resource block (RB) is defined as N in the frequency domain. 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 the SS / PBCH block used by the terminal for initial cell selection. Assuming a subcarrier spacing of 15kHz for FR1 and a subcarrier spacing of 60kHz 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". Common resource block number n for subcarrier spacing configuration μ in the frequency domain CRB μ The relationship between and resource element (k, l) is given as in Equation 1 below.

[0102] [Equation 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 spaced from 0 to N in a bandwidth part (BWP). BWP,i size,μ -1 numbering and i is the number of BWP. Physical resource block n in BWPi PRB and public resource block n CRB The relationship between is given by the following equation 2.

[0105] [Equation 2]

[0106]

[0107] is the common resource block where the BWP starts relative to common resource block 0.

[0108] Figure 4 The physical resource blocks in the wireless communication system to which the present disclosure can be applied are illustrated. Figure 5 The time slot structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0109] Reference 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 a 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 an activated BWP, and only one BWP may be activated for a terminal. In a resource grid, each element is called a resource element (RE) and may map a 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 a wideband CC (e.g., eMBB, URLLC, Mmtc, V2X, etc.), different parameter sets (e.g., subcarrier spacing, etc.) can 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 can instruct the terminal to operate only in part of the bandwidth instead of the full bandwidth of the wideband CC, and for convenience, the corresponding partial bandwidth is defined as a bandwidth part (BWP). The BWP can be configured with continuous RBs on the frequency axis and can 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 intermediate 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 (via 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 (via 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 establishes the RRC connection before, 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 (DLRS) 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] At the same time, when the terminal accesses the base station for the first time or there are no radio resources for signal transmission, it can perform a random access (RACH) process (S603 to S606) on the base station. For the random access process, the terminal can send a specific sequence as a preamble through a physical random access channel (PRACH) (S603 and S605), and can receive a response message to the preamble through a PDCCH and a corresponding PDSCH (S604 and S606). The contention-based RACH can additionally perform a contention resolution process.

[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 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] [Table 5]

[0122]

[0123]

[0124] 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 transport blocks (TBs) (e.g., MCS (modulation and coding 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 the scheduling of PUSCH (e.g., PUSCH power control, etc.), and the control information included in each DCI format may be predefined.

[0125] 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.

[0126] 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 a 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 CSIRNTI) or MCS-C-RNTI.

[0127] 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.

[0128] 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) request, 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] V2X (Vehicle to Everything) / Sidelink (SL) communication

[0133] Figure 7 A process of performing V2X or SL communication according to a transmission mode in a wireless communication system to which the present disclosure can be applied is illustrated.

[0134] 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, the transmission mode may be referred to as a mode or a resource allocation mode. In the following, for ease of explanation, the transmission mode in LTE may be referred to as an LTE transmission mode, and the transmission mode in NR may be referred to as an NR resource allocation mode.

[0135] 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 can be applied to general SL communication, and LTE transmission mode 3 can be applied to V2X communication.

[0136] 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 a UE associated with NR resource allocation mode 2.

[0137] Reference 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 UE to use for SL transmission (S8000). For example, the base station may send information related to SL resources and / or information related to 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.

[0138] For example, the first UE may receive information related to dynamic grant (DG) resources and / or information related to configuration 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, DG resources may be resources that the base station configures / allocates to the first UE via DCI. In the present disclosure, 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.

[0139] The first UE may send a PSCCH (eg, sidelink control information (SCI) or first-stage SCI) to the second UE based on resource scheduling (S8010).

[0140] 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).

[0141] 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) may be received from the second UE via the PSFCH.

[0142] 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 according to a pre-set rule. For example, the DCI may be a DCI for scheduling a SL. For example, the format of the DCI may be DCI format 3_0 or DCI format 3_1.

[0143] Reference Figure 7(b), in LTE transmission mode 2, LTE transmission mode 4 or NR resource allocation mode 2, the UE can determine the SL resources set by the base station / network or the SL transmission resources within the preset SL resources. For example, the set SL resources or pre-configured SL resources can be a resource pool. For example, the UE can autonomously select or schedule resources for SL transmission. For example, the UE can perform SL communication by selecting resources by itself within the configured resource pool. For example, the UE can perform a sensing and resource (re)selection process to select resources by itself within the selection window. For example, sensing can be performed on a subchannel basis.

[0144] The first UE, which has selected resources in the resource pool, may send a PSCCH (eg, SCI or first-stage SCI) to the second UE using the resources ( S8010 ).

[0145] The first UE may send a PSSCH (eg, second stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second UE (S8020).

[0146] The first UE may receive a PSFCH related to the PSCCH / PSSCH from the second UE ( S8030 ).

[0147] Reference Figure 7 (a) or Figure 7 (b), for example, the first UE may send SCI to the second UE on the PSCCH. Alternatively, for example, the first UE may send two consecutive SCIs (e.g., second-stage SCI) to the second UE on the PSCCH and / or PSSCH. In this case, the second UE may decode two consecutive SCIs (e.g., second-stage 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-stage SCI, or the first-stage SCI format, and the SCI sent on the PSSCH may be referred to as the second (second) SCI, the second SCI, the second-stage SCI, or the second-stage SCI format. For example, the first-stage SCI format may include SCI format 1-A, and the second-stage SCI format may include SCI format 2-A and / or SCI format 2-B.

[0148] Reference Figure 7 (a) or Figure 7 (b), in step S8030, the first UE may receive the PSFCH based on the following description. For example, the first UE and the second UE may determine the PSFCH resources based on the following description, and the second UE may send HARQ feedback to the first UE using the PSFCH resources.

[0149] Describes the UE procedures for reporting HARQ-ACK on the sidelink as specified in TS 38.213.

[0150] The UE may be instructed to send a PSFCH including HARQ-ACK information in response to PSSCH reception in an SCI format through scheduling PSSCH reception. The UE provides HARQ-ACK information including ACK or NACK or only NACK.

[0151] A number of time slots within a resource pool may be provided to the UE during the period of the PSFCH transmission opportunity resource indicated by sl-PSFCH-Period. If the number of time slots is 0, PSFCH transmission within the resource pool is disabled for the UE.

[0152] 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 ms according to TS 38.214, and N PSSCH PSFCH Provided by sl-PSFCH-Period.

[0153] The UE may be instructed by higher layers not to send a PSFCH containing HARQ-ACK information in response to receiving a PSSCH.

[0154] The UE provides HARQ-ACK information in a PSFCH transmission from the resource pool when the UE receives a PSSCH from the 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 sends the PSFCH in a first slot that includes PSFCH resources and corresponds to at least a number of slots provided by sl-MinTimeGapPSFCH of the resource pool after the last slot of PSSCH reception.

[0155] The UE may be provided with a physical resource block (PRB) in the resource pool indicated by sl-PSFCH-RB-Set. PRB,set PSFCH A set of PRBs in a resource pool indicated by sl-RB-SetPSFCH may be provided to the UE. PRB,setPSFCH A set of PRBs for PSFCH transmission including contention information. The UE expects to (pre)set different PRBs for contention information and HARQ-ACK information. For the resource pool N provided by sl-NumSubchannel SUBCH The number of subchannels and less than or equal to N PSSCH PSFCH The number of PSSCH time slots associated with the PSFCH time slots, the UE allocates the PSFCH time slots and PSSCH time slots associated with subchannel j to time slot i from M PRB,set PSFCH PRB [(i+j N 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 of i and continues in ascending order of j. The UE expects M PRB，set PSFCH N subch ·N PSSCH PSFCH multiples of.

[0156] The UE determines the number of available PSFCH resources for multiplexing HARQ-ACK or conflicting information in PSFCH transmission as R based on the indication of sl-PSFCH-CandidateResourceType. PRB,CS PSFCH =N type PSFCH ·M subch,slot PSFCH ·N CS PSFCH , where N CS PSFCH is the number of cyclic shift pairs in the resource pool provided by sl-NumMuxCS-Pair.

[0157] -When sl-PSFCH-CandidateResourceType is set to startSubCH, N typePSFCH =1, and M subch,slot PSFCH The PRBs are associated with the starting subchannel of the corresponding PSSCH.

[0158] -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.

[0159] -For conflicting information, the corresponding PSSCH is determined based on sl-PSFCH-Occasion.

[0160] PSFCH resources are first allocated in ascending order of PRB index from N type PSFCH ·M subch,slot PSFCH PRB indices, and then in ascending order of cyclic shift indexes from N CS PSFCH Rotate the pair index.

[0161] The UE determines the index of the PSFCH 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 , which corresponds to the reserved resources. Here, P ID The physical layer source identifier provided by SCI format 2-A / 2-B / 2-C for scheduling PSSCH reception or SCI format 2-A / 2-B / 2-C for reserving resources for conflicting information to be provided from 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 M is the identifier of the UE receiving the PSSCH indicated by the upper layer, otherwise ID is 0. For conflicting information, M ID is 0.

[0162] For PSFCH transmissions including HARQ-ACK information or contention information, the UE uses the following Table 6 to obtain the cyclic shift pair index and N corresponding to the PSFCH resource index: CS PSFCHThe value m0 is determined to calculate the value α of the cyclic shift.

[0163] Table 6 illustrates a set of cyclic shift pairs.

[0164] [Table 6]

[0165]

[0166] 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" to calculate the value of the cyclic shift α, the UE determines m as shown in Table 7 below cs value, 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.

[0167] [Table 7]

[0168] HARQ-ACK value 0(NACK) 1(ACK) Sequential cyclic shift 0 6

[0169] Table 8 illustrates the mapping of cyclic shifts of a sequence for PSFCH transmission from a cyclic shift pair to HARQ-ACK information bit values ​​when the HARQ-ACK information contains only NACK.

[0170] [Table 8]

[0171] HARQ-ACK value 0(NACK) 1(ACK) Sequential cyclic shift 0 N / A

[0172] Table 9 illustrates the mapping of cyclic shifts and collision information bit values ​​of sequences for PSFCH transmission from cyclic shift pairs.

[0173] [Table 9]

[0174] Conflicting Information Conflict information of the next reserved resource in SCI Sequence cyclic shift 0

[0175] Figure 8 The broadcast types used for V2X or SL communication in a wireless communication system to which the present disclosure can be applied are illustrated. 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) indicates unicast type SL communication, Figure 8 (c) represents multicast type SL communication. In the case of unicast type SL communication, the UE can communicate one-to-one with another UE. In the case of multicast type SL communication, the 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 multicast communication may be referred to as SL multicast communication, SL one-to-many communication, etc. In the following, the HARQ (Hybrid Automatic Repeat Request) process is described.

[0176] 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 a PSCCH targeted to the receiving UE and the receiving UE successfully decodes a transport block associated with the PSCCH, the receiving UE may generate an ACK. The receiving UE may then send a HARQ-ACK to the transmitting UE. On the other hand, if the receiving UE fails to successfully decode a transport block associated with the PSCCH after decoding the PSCCH targeted to the receiving UE, the receiving UE may generate a NACK. The receiving UE may then send a NACK to the transmitting UE.

[0177] 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.

[0178] (1) Multicast Option 1: If the receiving UE fails to decode the transmission associated with the PSCCH after decoding the PSCCH targeted at 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 targeted at 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.

[0179] (2) Multicast Option 2: If the receiving UE fails to decode the transport block associated with the PSCCH after decoding the PSCCH targeted to the receiving UE, the receiving UE may send a NACK to the sending UE via the PSFCH. Then, if the receiving UE decodes the PSCCH targeted to 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 sending UE via the PSFCH.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] The sidelink grant may be semi-persistently configured by RRC or dynamically received on PDCCH, which is autonomously selected 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.

[0184] 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.

[0185] UE / base station behavior for consistent LBT failure in SL transmission

[0186] NR Unlicensed (NR-U) refers to a mode that provides the technology required by cellular operators to integrate unlicensed spectrum into their wireless communication systems. NR-U enables uplink and downlink operations in unlicensed spectrum.

[0187] In NR-U, channel access for uplink and downlink relies on LBT functionality. The UE and / or base station may first sense the communication channel before transmission to determine whether there is no communication. If the communication channel is a broadband unlicensed carrier, the channel sensing process of NR-U may rely on sensing energy levels in multiple subbands of the communication channel. The base station may configure LBT parameters (e.g., type / duration, idle channel assessment parameters, etc.) for the UE.

[0188] 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.

[0189] In the NR-U system, both continuous uplink resource allocation and interleaved uplink resource allocation can be supported while complying with regulations. In interleaved uplink resource allocation, the basic unit of resource allocation for NR unlicensed channels can be an interlace. For example, a single interlace can consist of ten equally spaced resource blocks within a 20 MHz frequency bandwidth for a 15 kHz subcarrier spacing.

[0190] The base station can operate in dynamic or semi-static channel access mode. In dual channel access mode, the base station and the UE can apply LBT (Listen Before Talk) before performing transmission in a cell configured with shared spectrum channel access. When LBT is applied, the transmitter can monitor / detect the channel to determine whether the channel is idle or busy, and can perform transmission only when idle is detected on the channel.

[0191] NR radio access operating with shared spectrum channel access may operate in various modes, where a PCell, PSCell or SCell may operate in the shared spectrum and the SCell may or may not be configured for uplink.

[0192] The UE may monitor / detect consistent (or continuous) uplink LBT failures. If the physical layer performs an LBT procedure before transmission and reception are performed, an LBT failure indication may be sent from the physical layer to the MAC entity. LBT failure detection is performed per BWP, and LBT failure detection may be performed based on all uplink transmissions within the corresponding BWP. If a persistent uplink LBT failure is detected on an SCell, the UE may report the detected LBT failure to the corresponding gNB (e.g., MN in the case of MCG and SN in the case of SCG) via MACCE in a serving cell other than the SCell where the failure was detected.

[0193] If there are no resources available to send a MAC CE, the UE may send a Scheduling Request (SR) (to the base station). If a persistent uplink LBT failure is detected in the SpCell, the UE may initiate a RACH by switching to another UL BWP with RACH resources configured in that cell and report the LBT failure via a MAC CE. If multiple UL BWPs are available for switching, which UL BWP the UE selects may depend on the UE implementation.

[0194] For PSCell, if persistent uplink LBT failure is detected in all UL BWPs with configured RACH resources, the UE may declare SCG RLF and report the failure to the MN via 'SCGFailureInformation'. For PCell, if persistent uplink LBT failure is detected in all UL BWPs with configured RACH resources, the UE may declare Radio Link Failure (RLF).

[0195] The channel access priority class (CAPC) for radio bearers and MAC CE can be fixed or configurable:

[0196] - For filling BSR and recommended bit rate MAC, it is fixed as the lowest priority;

[0197] - For signaling radio bearer (SRB) 0, SRB1, SRB3 and other MAC CEs, fixed as the highest priority;

[0198] - For SRB2 and Data Radio Bearer (DRB), it can be configured by the base station.

[0199] When selecting a CAPC for a DRB, the base station may consider the 5QIs of all multiplexed QoS flows in the DRB, while also considering fairness between different service types and transmissions.

[0200] Table 10 below may indicate which CAPC should be used for which standardized 5QI (QoS Identifier), ie, which CAPC should be used for a given QoS flow. In Table 10, a lower CAPC value may mean a higher priority.

[0201] [Table 10]

[0202] CAPC 5Q 1 1、3、5、65、66、67、69、70、79、80、82、83、84、85 2 2、7、71 3 4、6、8、9、72、73、74、76 4 -

[0203] Here, 5QI may represent a value used to identify the QoS requirement of a specific service or business flow. The 5QI parameter may be used together with the CAP parameter to determine the priority of a specific service or business flow. When type 1 LBT is performed for uplink TB transmission and CAPC is not indicated in the DCI, the terminal may select CAPC according to the following method:

[0204] - If only MAC CE is included in the TB, the highest priority CAPC of the MAC CE is used;

[0205] - If a common control channel (CCCH) service data unit is included in the TB, the highest priority CAPC is used;

[0206] - If a dedicated control channel (DCCH) SDU is included in the TB, the highest priority CAPC of the DCCH is used;

[0207] - Otherwise, the lowest priority CAPC of the logical channel that multiplexes the MAC SDU in the TB may be used.

[0208] If SL transmission is supported in an unlicensed band, the UE can perform LBT for SL transmission. In a basic wireless communication system, CAPC is not mapped to the next SL radio bearer and MAC CE. Therefore, there is a problem that it is unclear how the UE should perform the channel access procedure for SL transmission.

[0209] The sidelink signaling radio bearer (SL-SRB) for an unprotected PC5-S message (e.g., direct link establishment request) for unicast NR sidelink communication may be referred to as SL-SRB0.

[0210] The SL-SRB of the PC5-S message that sets PC5-S security (eg, Direct Link Security Mode Command and Direct Link Security Mode Complete) may be referred to as SL-SRB1.

[0211] Except for Direct Link Security Mode Complete, the SL-SRB of the protected PC5-S message may be referred to as SL-SRB2.

[0212] For NR sidelink U2N (UE to network) relay, the sidelink signaling radio bearer for NR sidelink U2N relay related discovery messages (e.g., notification messages, request messages, and response messages) can be called SL-SRB4.

[0213] For NR sidelink L2 U2N relay operation, a PC5 relay RLC channel may be defined between the L2 U2N relay terminal and the L2 U2N remote UE. The PC5 relay RLC channel used to send SRB0 messages for the remote UE may be referred to as SL-RLC0.

[0214] (In response to the 'RRCReconfiguration' message including 'reconfigureWithSync' indicating path switching to L2 U2N relay UE) The sidelink RLC bearer of the SRB1 RRC messages of the remote UE (e.g., 'RRCResume', 'RRCReestablishment' and 'RRCReconfigurationComplete' messages) may be referred to as SL-RLC1.

[0215] In the RRC message, 'sl-RLC-ChannelID' may be used to indicate the PC5 relay RLC channel on the link between the L2 U2N relay UE and the L2 U2N remote UE.

[0216] For each PC5-RRC connection in unicast, one sidelink SRB (i.e., SL-SRB0) can be used to send PC5-S messages before PC5-S security is established. One sidelink SRB (i.e., SL-SRB1) can be used to send PC5-S messages to establish PC5-S security. One sidelink SRB (i.e., SL-SRB2) can be used to send PC5-S messages after protected PC5-S security is established. One sidelink SRB (i.e., SL-SRB3) is used to send protected PC5-RRC signaling, which can be sent only after PC5-S security is established. For U2N relay operation, one sidelink SRB (i.e., SL-SRB4) can be used to send and receive NR sidelink discovery messages.

[0217] For unicast NR sidelink communications, AS security is configured as integrity protection for PC5 signaling (SL-SRB1, SL-SRB2, and SL-SRB3) and user data (SL-DRB), and can be configured as encryption for PC5 signaling (e.g., SL-SRB1, SL-SRB2, and SL-SRB3 for direct link security mode complete messages only) and user data (SL-DRB). The encryption and integrity protection algorithms and parameters for PC5 unicast links are exchanged via upper layer PC5-S messages and can be applied to the corresponding PC5-RRC connection of the AS.

[0218] When AS security is enabled for the higher-layer PC5 unicast link, all messages in SL-SRB2 and SL-SRB3 and / or user data in SL-DRB corresponding to the PC5-RRC connection may be integrity protected and / or encrypted by PDCP.

[0219] When a key change for unicast for NR sidelink communication is indicated from higher layers, the UE may reconfigure the PDCP entities for SL-SRB1, SL-SRB2, SL-SRB3 and SL-DRB in the corresponding PC5-RRC connection.

[0220] Hereinafter, the operation of the terminal / base station when consecutive LBT failures occur for SL transmission may be described.

[0221] The UE may perform logical channel prioritization based on the CAPC value.

[0222] For example, in case of SL transmission for a SL grant in which the CPAC value is indicated as 1, the UE may select a possible destination for the mapped logical channel, configure a TB, and send the TB using the SL grant.

[0223] For example, when SL mode 1 (or SL resource allocation mode 1) is configured for the UE, the UE may receive the SL grant through DCI format 3_0. At this time, the base station may indicate the CAPC value of the SL grant through DCI format 3_0.

[0224] As another example, when SL mode 2 (or SL resource allocation mode 2) is configured for the UE, the CAPC value may be mapped on a per-resource pool and / or logical channel basis.

[0225] When the resource pool and the CAPC value are mapped, the UE may configure the TB by selecting a destination of a logical channel that may set the mapped CAPC for the selected sidelink grant generated from the resource pool.

[0226] As another example, the CAPC value may be configured based on the logical channel. When generating the selected sidelink grant for a particular logical channel, the UE may apply the CAPC mapped to the logical channel to the selected sidelink grant. For the selected sidelink grant, a destination of the logical channel to which the mapped CAPC may be set may be selected.

[0227] The CAPC of a logical channel can be mapped to the type of MAC CE sent by the logical channel, or the PQI value of SL data, PC5-S message, PC5-RRC message, logical channel priority, etc.

[0228] exist Fig. 9 In the example, for ease of explanation, the side link Tx (transmitting) UE is referred to as the first UE, and the side link Rx (receiving) UE is referred to as the second UE / second terminal. Fig. 9 In the present invention, the sidelink operation between the first UE and the second UE / third UE can be operated in an unlicensed band / spectrum or a shared spectrum.

[0229] Fig. 9 It is a diagram for explaining a process in which a first terminal performs communication according to one embodiment of the present disclosure.

[0230] The first UE may receive downlink control information (DCI) allocating a SL grant from a base station ( S910 ).

[0231] As an example of the present disclosure, the first UE may receive an RRC message from the base station for configuring SL resource allocation mode 1. After configuring SL resource allocation mode 1, the first UE may receive a DCI including SL grant from the base station. Here, the DCI may not include information indicating a channel access priority category (CAPC).

[0232] However, the operation of the first UE described below can also be applied when the first UE receives an RRC message from the base station for setting SL resource allocation mode 2. That is, since the first UE configured with SL resource allocation mode 2 does not receive the DCI including information indicating CAPC, the operation of the first terminal described below can be effectively applied.

[0233] The first UE may perform listen-before-talk (LBT) for at least one transport block (TB) transmission using a first CAPC selected based on a specific transport block (TB) corresponding to the SL grant ( S920 ).

[0234] Here, the specific TB corresponding to the SL authorization may be one, but is not limited thereto. Hereinafter, it is assumed that the number of specific TBs corresponding to the SL authorization is one, but even when the number of specific TBs is plural, the operation of the present disclosure may be applied.

[0235] For example, based on the first condition that the specific TB includes only SL MAC CE being satisfied, the first CAPC may be the CAPC with the highest priority. That is, if the specific TB includes only SL MAC CE, the first CAPC may be the CAPC with the highest priority.

[0236] Additionally or alternatively, based on the second condition that at least one TB includes a sidelink control channel (SCCH) being satisfied, the first CAPC may be the CAPC with the highest priority. That is, based on the specific TB including the SCCH, the first CAPC may be the CAPC with the highest priority.

[0237] Additionally or alternatively, based on the failure to satisfy the first condition and the second condition, the first CAPC may be a CAPC with the lowest priority having a logical channel of a MAC SDU multiplexed onto at least one TB.

[0238] For example, if the TB includes SL MAC CE and STCH data, the first CAPC may be a CAPC with the lowest priority for a logical channel having a MAC SDU multiplexed onto at least one TB.

[0239] In addition, the first CAPC can be used to send first sidelink control information (SCI) to schedule the SCCH or the first physical sidelink shared channel (PSSCH).

[0240] The first UE may establish a direct link with the second terminal by exchanging PC5-S messages with the second UE. The first UE may send a PC5-RRC message to the second UE to establish a SL radio bearer and a SL MAC CE. Here, the PC5-RRC message may include an SCCH.

[0241] The first UE may transmit a first SCI scheduling a first PSSCH including a specific TB to the second UE. The first UE may receive a first physical sidelink feedback channel (PSFCH) including HARQ-ACK information for the first PSSCH from the second UE.

[0242] As an example of the present disclosure, based on receiving a second SCI including information indicating a second CPAC and a second PSSCH scheduled by the second SCI from a second UE, the first UE can send a second PSFCH including HARQ-ACK information for the second PSSCH to the second UE based on the second CAPC using LBT.

[0243] In another example of the present disclosure, based on receiving a second SCI from a second UE that does not include information indicating a second CAPC and a second PSSCH scheduled by the second SCI, the first UE may send a second PSFCH including HARQ-ACK information for the second PSSCH to the second UE using LBT based on a CAPC corresponding to i) an RRC message received from the second UE or the base station or ii) at least one of at least one resource pool configured by the base station.

[0244] exist Fig. 9 The method performed by the first UE described in the example can be performed by the first device (100) of Figure 13.

[0245] For example, one or more processors (102) of the first device (100) of Figure 13 can be configured to receive a DCI allocating a SL grant from a base station via one or more transceivers (106). The one or more processors (102) can be configured to perform LBT for at least one TB transmission using a first CAPC selected based on a specific TB corresponding to the SL grant.

[0246] 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.

[0247] Fig.10 is a diagram for explaining a process in which a second UE performs communication according to one embodiment of the present disclosure.

[0248] The second UE may receive a PSSCH including at least one transport block from the first UE based on the first CAPC selected through a specific TB corresponding to the SL grant ( S1010 ).

[0249] Here, a DCI for allocating SL grant may be sent from the base station to the first UE. And, the DCI may not include information indicating the CAPC.

[0250] The second UE may transmit a physical sidelink feedback channel (PSFCH) including HARQ-ACK information for the PSSCH to the first UE (S1020).

[0251] Here, based on the first condition that the specific TB includes only SL MAC CE being satisfied, the first CAPC may be the CAPC with the highest priority. Based on the second condition that the specific TB includes SCCH being satisfied, the first CAPC may be the CAPC with the highest priority.

[0252] exist Fig.10 The method performed by the second UE described in the example can be performed by the second device (200) of Figure 13.

[0253] For example, one or more processors (202) of the second device (200) of Figure 13 can be configured to receive a PSSCH including at least one transport block from a first UE through one or more transceivers (206) based on a first CAPC selected through a specific TB corresponding to an SL grant. The one or more processors (202) can be configured to send a PSFCH including HARQ-ACK information for the PSSCH to the first UE through one or more transceivers (206).

[0254] 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.

[0255] In the following, reference will be made to Fig.11 A SL transmission method based on a CAPC using a channel access procedure according to one embodiment of the present disclosure is described.

[0256] UE#1 may receive an RRC message to configure CAPC for the SL radio bearer and SL MAC CE (S1110).

[0257] The CAPC for SL radio bearers and MAC CE can be fixed or configurable.

[0258] For example, data on the Sidelink Control Channel (SCCH) may be fixed as the highest priority (or lowest priority) (eg, depending on what signaling is carried on the SCCH), or may be configured by an RRC message.

[0259] For example, the SL CSI reporting MAC CE may be fixed as the highest priority (or the lowest priority) or may be configured using an RRC message.

[0260] For example, the inter-SL UE coordination request MAC CE and the inter-SL UE matching report MAC CE may be fixed to the highest priority (or the lowest priority), or may be configured by an RRC message.

[0261] For example, the SL DRX command MAC CE may be fixed as the highest priority (or the lowest priority), or may be configured using an RRC message.

[0262] For example, all STCH (Sidelink Traffic Channel) data may be configured as RRC messages.

[0263] For example, padding may be fixed to the lowest priority.

[0264] An example of how CAPC values ​​are mapped to SL logical channels or SL MAC CEs for SL transmission may be shown in Table 11 below. A lower CAPC value may mean a higher priority. The lowest priority CAPC may be set to 4, and the highest priority CAPC may be configured to 1.

[0265] [Table 11]

[0266]

[0267] For configurable CAPC, a UE in RRC_IDLE or RRC_INACTIVE state can receive system information to configure the CAPC for SL radio bearers and SL MAC CE. As another example, for configurable CAPC, a UE in RRC_CONNECTED state can receive a dedicated RRC message to configure the CAPC for SL radio bearers and SL MAC CE. When out of network coverage, the UE can use SL pre-configuration to determine the CAPC for SL transmission. System information, dedicated RRC message, or SL pre-configuration can configure the CAPC for SL radio bearers and SL MAC CE, as shown in the following table.

[0268] As an example of the present disclosure, CAPC may be configured per 'SL-LogicalChannelConfig' (ie, per SL logical channel configuration). 'SL-LogicalChannelConfig' is an RRC parameter (ie, information element) for setting SL logical channel parameters and may be configured as shown in Table 12.

[0269] [Table 12]

[0270]

[0271]

[0272] As an example of the present disclosure, CAPC may be configured per 'SL-RLC-ChannelConfig' (i.e., per 'sl-RLC-ChannelID'). 'SL-RLC-ChannelConfig' may specify SL RLC bearer configuration information for a PC5 relay RLC channel between an L2 U2N (UE to network) relay UE and an L2U2N remote UE, and may be configured as shown in Table 13.

[0273] [Table 13]

[0274]

[0275] As an example of the present disclosure, CAPC may be set per 'sl-LogicalChannelIdentity' (ie, per logical channel ID). As shown in Table 14 below, 'sl-LogicalChannelIdentity' may be included in 'SL-LogicalChannelConfigPC5'.

[0276] [Table 14]

[0277]

[0278] As an example of the present disclosure, CAPC may be configured per SL-PQFI, ie, per PC5 QoS flow identifier (PQFI). As disclosed in Table 15, SL-PQFI information may be included in the SL-PQFI configuration information.

[0279] [Table 15]

[0280]

[0281] As an example of the present disclosure, CAPC may be configured per cycle of 'sl-LogicalChannelIdentiy'. As disclosed in Table 16, 'sl-LogicalChannelIdentiy' information may be configured.

[0282] [Table 16]

[0283]

[0284]

[0285] In one example of the present disclosure, CAPC can be configured per resource pool. In another example, CAPC can be set per L2 (Layer 2) destination ID or per source ID and destination ID. If the system information, dedicated RRC message, or SL preset does not configure the CAPC for the SL radio bearer, the CAPC can be determined based on the PQI of the SL radio bearer. The PQI can be a special 5QI. The PQI can be used as a reference for parameters that control the QoS forwarding processing of packets via the PC5 QoS characteristics (i.e., the PC5 reference point). Standardized PQI values ​​can be mapped one-to-one to standardized combinations of PC5 QoS characteristics.

[0286] For example, one or more PQI values ​​may be specified to be mapped to a particular CAPC in the manner described below.

[0287] When selecting the CAPC for a SL radio bearer (SLRB), the base station may consider the PQIs of all multiplexed QoS flows corresponding to the DRB, while also considering fairness between different service types and transmissions.

[0288] Table 17 below may indicate which CAPC should be used for normalized PQI, ie, which CAPC should be used for a given QoS flow. Here, a lower CAPC RKQT may mean a higher priority.

[0289] [Table 17]

[0290] CAPC PQI 1 1,3,5 2 2,7, 3 4,6,8,9 4 -

[0291] When SL mode 1 is configured for the UE, the UE may receive DCI format 3_0 or DCI format 3_x that may indicate a CAPC for SL authorization. The UE receiving the DCI may perform SL transmission using a type 1 or type 2 channel access procedure with the indicated CAPC. When SL mode 2 is configured for the UE, when the UE generates a selected sidelink grant for a logical channel with SL data or SL MAC CE, the UE may select a resource pool of logical channels that may be mapped to the SL data or SL MAC CE, and determine a CAPC for SL transmission of the selected sidelink grant from the selected resource pool.

[0292] Here, for example, a CAPC or SL MAC CE mapped to the SL data may be associated with the selected side link grant. As another example, a CAPC mapped to the selected resource pool may be associated with the selected side link grant.

[0293] If SL Mode 1 is configured for the UE, when the UE performs Type 1 LBT for SL transmission of a TB on SL resources and CAPC is not indicated in the DCI allocating the SL resources; or

[0294] If SL Mode 2 is configured for the UE, when the UE performs Type 1 LBT for SL transmission of a TB on SL resources in the selected sidelink of a resource pool on a carrier and CAPC is not configured for the selected sidelink grant of the resource pool or carrier, or the base station does not indicate CAPC for SL Mode 2:

[0295] The UE may select the CAPC as follows:

[0296] If only SL MAC CE is included in the TB, the highest priority CAPC of the corresponding MAC CE is used;

[0297] If a SCCH SDU carrying PC5-S signaling is included in the TB, the highest priority CAPC is used; or

[0298] If the SCCH SDU carrying the PC5-RRC message is included in the TB, the highest priority CAPC of the SCCH carrying the PC5-RRC message is used;

[0299] If the SCCH or STCH SDU carrying the RRC message in SL-RLC0 is included in the TB, the highest priority CAPC of the SCC or STCH carrying the RRC message in SL-RLC0 is used;

[0300] If a SCCH or STCH SDU carrying an RRC message in SL-RLC1 is included in the TB, the highest priority CAPC of the SCCH or STCH SDU carrying an RRC message in SL-RLC1 is used; or

[0301] Otherwise, the lowest priority CAPC with the SL logical channel that multiplexes the MAC SDU in the TB may be used.

[0302] One or more of the above methods for determining the CAPC for SL transmissions are used in the following steps.

[0303] In step S1120, UE#1 performs LBT using the determined CAPC, and may establish a direct link with UE#2 for unicast service by exchanging PC5-S signaling with UE#2.

[0304] UE#1 can use the CAPC corresponding to the SCCH carrying the PC5-S message to send the SCCH carrying the PC5-S message using the type 1 or type 2 channel access procedure. UE#1 can also use the CAPC to send the SCI that schedules the SCCH.

[0305] At step S1130, UE#1 may perform LBT using the determined CAPC, and send PC5-S signaling to UE#2 and UE#3 for a multicast service (or broadcast service).

[0306] UE#1 may transmit a PSSCH carrying multicast (or broadcast) signaling or data using a type 1 or type 2 channel access procedure using a CAPC corresponding to multicast SL transmission (or broadcast SL transmission) (ie, a CAPC corresponding to a broadcast type).

[0307] Alternatively, for SL transmission, the CAPC may be determined based on the destination of the multicast (or broadcast). That is, the CAPC may correspond to the destination ID of the multicast (or broadcast) configured through system information, a dedicated RRC message, or a preset. If the destination is not configured through an RRC message, a default CAPC may be determined for the corresponding SL transmission. The CAPC may also be used by UE#1 to send the SCI that schedules the PSSCH.

[0308] A PC5-RRC connection may be established between UE#1 and UE#2 (S1140). UE#1 may perform LBT using the determined CAPC (S1150).

[0309] UE#1 may send a PC5-RRC message to UE#2 to configure the SL radio bearer and MAC CE (S1160). In the PC5-RRC message, CAPC may be configured for a specific SL radio bearer or a specific SL MAC CE.

[0310] Specifically, UE#1 may use a type 1 or type 2 channel access procedure with the CAPC corresponding to the SCCH carrying the PC5-RRC message to send the SCCH carrying the PC5-RRC message. CAPC may also be used by UE#1 to send the SCI that schedules the SCCH.

[0311] UE#2 may perform LBT using the CAPC determined based on the RRC message received from UE#1 (S1165). In step S1170, UE#2 may transmit a PSSCH carrying SL data of the SL-DRB to UE#1 after transmitting the SCI to UE#1.

[0312] UE#1 may receive SCI and PSSCH from UE#2, and send SL HARQ-ACK for PSCCH transmission of SL data of SL-DRB to UE#2 (S1175).

[0313] Specifically, UE#2 may send a PSSCH carrying SCI and SL data of SL-DRB to UE#1. In the above steps, UE#2 may use a CAPC corresponding to STCH based on the CAPC configured by UE#1 or the CAPC indicated / configured by the gNB, and use a type 1 or type 2 channel access procedure to send SCI and a PSSCH carrying a TB including the STCH carrying SL data of SL-DRB.

[0314] UE#2 can use the CAPC indicated / configured by the base station. For example, if UE#2 is configured as SL mode 1 (i.e., SL resource allocation mode 1), the CAPC can be indicated by the DCI and PSSCH of the SL resources allocated by the SCI. At this time, UE#2 can use the CAPC indicated by the base station through the DCI.

[0315] When UE#2 is configured as SL mode 2 (ie, SL resource allocation mode 2), CAPC can be configured by the base station via an RRC message (eg, corresponding STCH for SL-DRB). If the CAPC configured by the base station is not available, UE#2 can use the CAPC configured by UE#2.

[0316] If the CAPC configured by the base station and the CAPC set by UE#1 cannot be used, UE#2 can use the CAPC mapped to the PQI of SL-DRB in Table 17 or the CAPC configured by SL pre-configuration.

[0317] The SCI of a TB scheduling SL data may indicate a CAPC for PSFCH transmission of HARQ-ACK or RLC ACK carrying SL data for the TB.

[0318] At step S1170 , UE# 1 may transmit a PSFCH carrying HARQ-ACK using a Type 1 or Type 2 channel access procedure using the CAPC indicated by the SCI received from UE# 2 .

[0319] For example, if the SCI does not indicate a CAPC for HARQ-ACK transmission, UE#1 may transmit a PSFCH carrying HARQ-ACK using a Type 1 or Type 2 channel access procedure using one of the following CAPCs:

[0320] Option 1: Fixed CAPC for SL HARQ-ACK

[0321] Option 2: CAPC configured for the destination indicated by the received SCI and PSSCH

[0322] Option 3: CAPC of resource pool, carrier or cell configured to send SL HARQ-ACK

[0323] Option 4: CAPC associated with the selected sidelink grant for sending SL HARQ-ACK

[0324] Option 5: Default CAPC

[0325] Option 6: CAPC configured by UE#2 in RRC message for the above purpose

[0326] Option 7: CAPC configured by the base station in the RRC message for the above purpose

[0327] UE#1 may perform LBT using the determined CAPC (S1180). At step S1185, UE#1 may send a PSCCH carrying SCI and SL MAC CE to UE#2 and / or UE#3. UE#2 and / or UE#3 may send a PSFCH including a SL HARQ-ACK based on only NACK to UE#1 (S1190).

[0328] UE#1 may send SCI and PSSCH using Type 1 or Type 2 channel access procedures with fixed CAPC for SL MAC CE.

[0329] Alternatively, if the SL MAC CE (eg, SL CSI reporting MAC CE) is triggered by the SCI sent by UE#2, the CAPC indicated by UE#2 (ie, through the SCI) may be used for the Type 1 or Type 2 channel access procedure.

[0330] If the SCI does not indicate CAPC, UE#1 may transmit the SCI and PSCCH using a Type 1 or Type 2 channel access procedure with CAPC according to one of the following options.

[0331] Option 1: Fixed CAPC for SL HARQ-ACK

[0332] Option 2: CAPC configured for the destination indicated by the received SCI and PSSCH

[0333] Option 3: CAPC of the resource pool, carrier or cell configured to send SL HARQ-ACK

[0334] Option 4: CAPC associated with the selected sidelink grant for sending SL HARQ-ACK

[0335] Option 5: Default CAPC

[0336] Option 6: CAPC set by UE#2 in RRC message for the above purpose

[0337] Option 7: CAPC set by the base station in the RRC message for the above purpose

[0338] In the above steps, the MAC entity of UE#1 or UE#2 can perform a logical channel priority process for each SL resource (i.e., each SL grant scheduled by the SCI) to generate a MAC PDU (i.e., TB) for SL resource transmission according to the method described below.

[0339] Configuring logical channel priority in MAC

[0340] For each SCI and SL grant corresponding to a new HARQ transmission from UE#1 or UE#2, the MAC entity of the UE may select a destination associated with one of the unicast, groupcast, and broadcast logical channels that has at least one MAC CE and the highest priority logical channel among the logical channels for both the MAC CEs of the SL grant associated with the SCI that satisfies the following conditions:

[0341] -SL data can be used for transmission; and

[0342] - if there is a logical channel with SBj>0, then SBj>0; and

[0343] - if the SL grant is of type 1, 'sl-configuredGrantType1Allowed' (if configured) is set to 'true';

[0344] - (if configured) 'sl-AllowedCG-List' includes the configured authorization index associated with the SL authorization;

[0345] - If PSFCH is not configured for SL grant associated with SCI, 'sl-HARQ-FeedbackEnabled' is set to disabled;

[0346] - SL data or SL MAC CE may be mapped to a CAPC value lower than or equal to the CAPC value indicated or configured for the SL grant (eg, a SL logical channel based on the SL data's PQI or the SL data CAPC).

[0347] When CAPC is indicated by a DCI indicating a SL authorization, when CAPC is indicated by an SCI triggering a SL data or SL MAC CE, when CAPC is configured by an RRC message for a SL authorization, or when CAPC is associated with a selected side link grant for a SL authorization, an operation of mapping the SL data or SL MAC CE to a CAPC value lower than or equal to a CAPC value indicated or configured for a SL authorization may be performed.

[0348] If multiple destinations have logical channels that satisfy all of the above conditions and have the same highest priority, or if multiple destinations have logical channels with the same priority and / or MAC CE as the MAC CE and satisfy all of the above conditions, the selection of a specific destination among the above destinations may be determined by the UE implementation.

[0349] The UE may then select a logical channel satisfying all of the following conditions among the logical channels belonging to the selected destination.

[0350] -SL data can be used for transmission; and

[0351] - if there is a logical channel with SBj>0, then SBj>0; and

[0352] - if the SL grant is configured grant type 1, then (if configured) 'sl-configuredGrantType1Allowed' is set to 'true';

[0353] - (if configured) 'sl-AllowedCG-List' includes the configured authorization index associated with the SL authorization; and

[0354] 1> If PSFCH is configured for a sidelink grant associated with SCI:

[0355] 2> If 'sl-HARQ-FeedbackEnabled' is set to enabled for the highest priority logical channel that meets the above conditions, then 'sl-HARQ-FeedbackEnabled' may be set to enabled; or

[0356] 2> If 'sl-HARQ-FeedbackEnabled' is set to disabled for the highest priority logical channel that meets the above conditions, 'sl-HARQ-FeedbackEnabled' may be set to disabled.

[0357] 3> Otherwise:

[0358] 4>'sl-HARQ-FeedbackEnabled' can be set to disabled.

[0359] - SL data or SL MAC CE may be mapped to a CAPC value lower than or equal to the CAPC value indicated or configured for the SL grant (eg, a SL logical channel based on the SL data's PQI or the SL data CAPC).

[0360] If the CAPC is indicated by a DCI indicating a SL grant, if the CAPC is indicated by an SCI triggering a SL data or SL MAC CE, if the CAPC is configured by an RRC message for a SL grant, or if the CAPC is a SL grant for a SL; or if the CAPC is associated with a selected sidelink grant for a SL grant, operations may be performed in which the SL data or SL MAC CE is mapped to a CAPC value that is lower than or equal to a CAPC value indicated or configured for a SL grant.

[0361] For transmission of a MAC PDU carrying only a CSI report MAC CE, a sidelink DRX command MAC CE, a sidelink inter-UE coordination request MAC CE, or a sidelink inter-UE alignment information MAC CE, the HARQ feedback enable / disable indicator may be configured to be disabled.

[0362] For each SCI and SL grant corresponding to a new transmission, the MAC entity may generate a MAC PDU including SL data only on the logical channel selected for the HARQ entity. The terminal may send a MAC PDU (i.e., TB) using a Type 1 or Type 2 channel access procedure with a CAPC indicated or set for a SL grant.

[0363] When describing the present disclosure, uplink transmissions, grants, and resources may be used to replace sidelink transmissions, grants, and resources.

[0364] Through the above-mentioned embodiment, (when the UE performs SL transmission in an unlicensed band), the UE can generate a transport block from one or more logical channels or MAC CE in the logical channel prioritization of the SL resources by utilizing the channel access procedure determined for the CAPC for the SL resources.

[0365] General devices to which the present disclosure can be applied

[0366] Fig.12 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0367] Reference Fig.12 , the first wireless device 100 and the second wireless device 200 can send and receive wireless signals through various radio access technologies (e.g., LTE, NR).

[0368] 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, suggestions, methods, and / or operational flow charts disclosed in the present disclosure.

[0369] For example, the processor 102 may process the information in the memory 104 to generate first information / signal, and then transmit a wireless signal including the first information / signal through the transceiver 106. In addition, the processor 102 may receive a wireless signal including second information / signal through the transceiver 106, and then store information obtained from the signal processing of the second information / signal in the memory 104.

[0370] 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 the processing controlled by the processor 102 or for executing the descriptions, functions, processes, suggestions, methods and / or operational flowcharts 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.

[0371] 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, suggestion, 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 the wireless signal including the fourth information / signal through the transceiver 206, and then store the information obtained by the 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 codes including commands for executing all or part of the processing controlled by the processor 202 or for executing the description, function, process, suggestion, 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.

[0372] In the following, the hardware elements of the wireless device 100, 200 will be described in more detail. Without limitation thereto, 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, suggestions, methods, and / or operational flowcharts 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, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors 102, 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide it to one or more transceivers 106, 206. One or more processors 102, 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106, 206 according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed in the present disclosure, and obtain the PDU, SDU, message, control information, data, or information.

[0373] 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. For 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 descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, and the like. Firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operational flow charts 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 descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in the present disclosure may be implemented by using firmware or software in the form of codes, commands and / or command sets.

[0374] 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, cache 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 various technologies such as wired or wireless connections.

[0375] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the method and / or operation flow chart 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, suggestion, method and / or operation flow chart 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 transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the description, functions, processes, suggestions, methods, and / or operation flow charts, etc. disclosed in the present disclosure through one or more antennas 108, 208. In the present disclosure, 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 into baseband signals to process received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. 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 into RF band signals. Thus, one or more of the transceivers 106 , 206 may include (analog) oscillators and / or filters.

[0376] The above-mentioned embodiments are to combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be regarded as 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 a combination of some 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. Obviously, the embodiments may include claims that do not have a clear reference relationship in the combined claims, or may be included as new claims by modification after application.

[0377] It is clear to those skilled in the relevant 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 disclosure 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 disclosure.

[0378] 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 enable software or commands, etc. to be stored and executable 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, for example, 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, for example, 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 this disclosure may be stored in any machine-readable medium to control the hardware of a processing system, and may be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0379] 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. Additionally 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, for 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 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 is not limited to the above names. For example, ZigBee technology can generate a PAN (Personal Area Network) related to small / low power digital communication based on various standards (e.g., IEEE 802.15.4, etc.), and can be called various names.

[0380] Industrial Applicability

[0381] The method proposed in the present disclosure is mainly described based on examples applied to 3GPP LTE / LTE-A and 5G systems, but can also be applied to various wireless communication systems other than 3GPP LTE / LTE-A and 5G systems.

Claims

1. A method for performing sidelink (SL) communication by a first user equipment (UE) in a wireless communication system, the method comprising the following steps: Receiving downlink control information DCI for allocating SL grant from a base station, wherein the DCI does not include information indicating a channel access priority class CAPC; and performing a listen-before-talk (LBT) for transmission of a specific transport block TB corresponding to the SL grant using a first CAPC selected based on the specific transport block TB corresponding to the SL grant, wherein a first condition based on that the specific TB includes only SL medium access control MAC control element CE is satisfied, the first CAPC is a CAPC with the highest priority, and Wherein, based on that the second condition that the specific TB includes a side link control channel SCCH is satisfied, the first CAPC is a CAPC with the highest priority.

2. The method according to claim 1, wherein: Based on the first condition and the second condition not being satisfied, the first CAPC is a CAPC with the lowest priority for a logical channel having a MAC SDU multiplexed with the specific TB.

3. The method according to claim 1, wherein: Based on the PC5-S message exchanged with the second UE, a direct link is established between the first UE and the second UE.

4. The method according to claim 1, wherein: The first CAPC is used to send first sidelink control information SCI for scheduling the SCCH or the first physical sidelink shared channel PSSCH.

5. The method according to claim 3, wherein: sending a PC5-RRC message for configuring a SL radio bearer and the SL MAC CE to the second UE, and The PC5-RRC message includes the SCCH.

6. The method according to claim 5, wherein: sending a first SCI scheduling a first PSSCH including the specific TB to the second UE, and A first physical sidelink feedback channel (PSFCH) including HARQ-ACK information for the first PSSCH is received from the second UE.

7. The method according to claim 3, wherein: Based on a second SCI including information indicating a second CPAC and a second PSSCH scheduled by the second SCI received from the second UE, a second PSFCH including HARQ-ACK information for the second PSSCH is sent to the second UE using LBT based on the second CAPC.

8. The method according to claim 3, wherein: Based on a second SCI received from the second UE that does not include information indicating a second CAPC and a second PSSCH scheduled by the second SCI, based on a CAPC corresponding to an RRC message received from the second UE or the base station or at least one of the at least one resource pools configured by the base station, a second PSFCH including HARQ-ACK information for the second PSSCH is sent to the second UE using LBT.

9. The method according to claim 1, wherein: An RRC message for configuring SL resource allocation mode 1 is received from the base station.

10. A first user equipment UE for performing sidelink (SL) communication in a wireless communication system, the first UE comprising: at least one transceiver; as well as at least one processor coupled to the at least one transceiver, Wherein, the at least one processor is configured to: Receiving, by the at least one transceiver, downlink control information DCI for allocating SL grant from a base station, wherein the DCI does not include information indicating a channel access priority class CAPC; and performing a listen-before-talk (LBT) for transmission of a specific transport block TB corresponding to the SL grant using a first CAPC selected based on the specific transport block TB corresponding to the SL grant, wherein a first condition based on that the specific TB includes only SL medium access control MAC control element CE is satisfied, the first CAPC is a CAPC with the highest priority, and Wherein, based on that the second condition that the specific TB includes a side link control channel SCCH is satisfied, the first CAPC is a CAPC with the highest priority.

11. A method for performing sidelink (SL) communication by a second user equipment (UE) in a wireless communication system, the method comprising the following steps: receiving a physical sidelink shared channel PSSCH from the first UE, the PSSCH comprising a specific TB based on a first channel access priority category CAPC selected by a specific transport block TB corresponding to the SL grant; and sending a physical side link feedback channel to the first UE, wherein the physical side link feedback channel includes hybrid automatic repeat request HARQ-acknowledgement ACK information for the PSSCH, wherein downlink control information DCI for allocating the SL grant is sent from the base station to the first UE, The DCI does not include information indicating a channel access priority category CAPC, wherein a first condition based on that the specific TB includes only SL medium access control MAC control element CE is satisfied, the first CAPC is a CAPC with the highest priority, and Wherein, based on that the second condition that the specific TB includes a side link control channel SCCH is satisfied, the first CAPC is a CAPC with the highest priority.

12. A second user equipment UE performing sidelink (SL) communication in a wireless communication system, the second UE comprising: at least one transceiver; as well as at least one processor coupled to the at least one transceiver, Wherein, the at least one processor is configured to: receiving, by the at least one transceiver, a physical sidelink shared channel PSSCH from the first UE, the PSSCH comprising a specific TB based on a first channel access priority category CAPC selected by a specific transport block TB corresponding to the SL grant; and Sending a physical side link feedback channel to the first UE through the at least one transceiver, wherein the physical side link feedback channel includes hybrid automatic repeat request HARQ-acknowledgement ACK information for the PSSCH, wherein downlink control information DCI for allocating the SL grant is sent from the base station to the first UE, The DCI does not include information indicating a channel access priority category CAPC, wherein a first condition based on that the specific TB includes only SL medium access control MAC control element CE is satisfied, the first CAPC is a CAPC with the highest priority, and Wherein, based on that the second condition that the specific TB includes a side link control channel SCCH is satisfied, the first CAPC is a CAPC with the highest priority.

13. A processing device, the processing device being configured to control a first user equipment UE to perform side link SL communication in a wireless communication system, the processing device comprising: 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 the following operations when executed by the at least one processor; The operations include: Receiving downlink control information DCI for allocating SL grant from a base station, wherein the DCI does not include information indicating a channel access priority class CAPC; and performing a listen-before-talk (LBT) for transmission of a specific transport block TB corresponding to the SL grant using a first CAPC selected based on the specific transport block TB corresponding to the SL grant, wherein a first condition based on that the specific TB includes only SL medium access control MAC control element CE is satisfied, the first CAPC is a CAPC with the highest priority, and Wherein, based on that the second condition that the specific TB includes a side link control channel SCCH is satisfied, the first CAPC is a CAPC with the highest priority.

14. At least one non-transitory computer-readable medium storing at least one instruction, The at least one instruction is executed by at least one processor so that the device performing side link SL communication in the wireless communication system is used to: Receive downlink control information DCI for allocating SL grant from the base station, wherein: The DCI does not include information indicating a channel access priority class CAPC; as well as performing a listen-before-talk (LBT) for transmission of a specific transport block TB corresponding to the SL grant using a first CAPC selected based on the specific transport block TB corresponding to the SL grant, wherein a first condition based on that the specific TB includes only SL medium access control MAC control element CE is satisfied, the first CAPC is a CAPC with the highest priority, and Wherein, based on that the second condition that the specific TB includes a side link control channel SCCH is satisfied, the first CAPC is a CAPC with the highest priority.

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