Method and apparatus for performing sidelink communication in a wireless communication system - Patents.com

Abstract

A method and an apparatus for performing sidelink communication in a wireless communication system are disclosed. A method for performing sidelink communication by a first terminal according to an embodiment of the present disclosure may include selecting a destination based on a channel access priority class (CAPC) value corresponding to a specific selected SL grant, selecting at least one logical channel for the selected destination, configuring at least one transport block (TB) based on the selected at least one logical channel, and transmitting the at least one TB to at least one other terminal corresponding to the destination via the one or more transceivers.

Description

[Technical field]

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

[0002] Mobile communication systems were developed to provide voice services while ensuring user activity. However, the scope of mobile communication systems has expanded beyond voice to data services, and currently, resource shortages are occurring due to the explosive increase in traffic, and users are demanding faster services, so there is a demand for more advanced mobile communication systems.

[0003] The requirements for the next generation mobile communication system are to accommodate large and explosive data traffic, dramatically increase the transmission rate per user, accommodate a significantly increased number of connected devices, and support very low end-to-end latency and high energy efficiency. To this end, various technologies such as Dual Connectivity, Massive Multiple Input Multiple Output (MAMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), super wideband support, and Device Networking are being researched. Summary of the Invention [Problem to be solved by the invention]

[0004] A technical problem of the present disclosure is to provide a method and apparatus for performing sidelink communication in a wireless communication system.

[0005] The technical problem of the present disclosure is to provide a method and apparatus for configuring a transport block (TB) for transmission of sidelink resources determined by a channel access scheme based on channel access priority class (CAPC).

[0006] The technical problems to be achieved by the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Means for solving the problem]

[0007] As one embodiment of the present disclosure, a method for a first terminal performing sidelink communication in a wireless communication system may include a step of selecting a destination based on a channel access priority class (CAPC) value corresponding to a specific selected SL grant, a step of selecting at least one logical channel for the selected destination, a step of constructing at least one transmission block (transport block, TB) based on the selected at least one logical channel, and a step of transmitting the at least one TB to at least one other terminal corresponding to the destination.

[0008] As another embodiment of the present disclosure, a method for a second terminal performing sidelink communication in a wireless communication system may include a step of establishing an SL unicast connection with a first terminal device, a step of receiving from the first terminal device at least one TB generated based on at least one logical channel corresponding to a destination associated with a CAPC value corresponding to a specific selected SL grant, and a step of transmitting HARQ-ACK information for the at least one TB to the first terminal on a physical sidelink feedback channel. Effect of the Invention

[0009] According to an embodiment of the present disclosure, a method and apparatus for performing sidelink communication in a wireless communication system may be provided.

[0010] As one embodiment of the present disclosure, a method and apparatus for configuring a transport block (TB) for transmitting sidelink resources determined by a channel access scheme based on a channel access priority class (CAPC) may be provided.

[0011] The effects obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief description of the drawings]

[0012] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide examples of the present disclosure and, together with the detailed description, explain the technical features of the present disclosure.

[0013] [Figure 1] FIG. 1 is a diagram illustrating the structure of a wireless communication system to which the present disclosure can be applied. [Diagram 2] FIG. 1 illustrates a frame structure in a wireless communication system to which the present disclosure can be applied. [Diagram 3] FIG. 1 illustrates a resource grid in a wireless communication system to which the present disclosure can be applied. [Figure 4] FIG. 1 is a diagram illustrating a physical resource block in a wireless communication system to which the present disclosure can be applied. [Diagram 5] FIG. 1 illustrates a slot structure in a wireless communication system to which the present disclosure can be applied. [Figure 6] 1 is a diagram illustrating physical channels used in a wireless communication system to which the present disclosure can be applied and a general signal transmission / reception method using the physical channels. [Figure 7]FIG. 1 is a diagram showing a procedure for performing V2X or SL communication in a transmission mode in a wireless communication system to which the present disclosure can be applied. [Figure 8] FIG. 11 is a diagram illustrating a cast type for V2X or SL communication in a wireless communication system to which the present disclosure can be applied. [Figure 9] FIG. 2 is a diagram for explaining a process in which a first terminal performs communication according to an embodiment of the present disclosure. [Figure 10] FIG. 13 is a diagram for explaining a process in which a base station performs communication according to one embodiment of the present disclosure. [Figure 11] A diagram for explaining a signaling procedure between a base station, a first terminal, and a second terminal according to one embodiment of the present disclosure. [Figure 12] 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, and is not intended to show the only embodiment in which the present disclosure can be implemented. The detailed description below includes specific details to provide a complete understanding of the present disclosure. However, it is understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0015] In some cases, in order to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or may be shown in the form of a block diagram focusing on the core functions of each structure and device.

[0016] In this disclosure, when an element is "coupled," "coupled," or "connected" to another element, this can include a direct connection as well as an indirect connection where there is still another element between them. Also, in this disclosure, the terms "including" or "having" specify the presence of a stated feature, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0017] In this disclosure, terms such as "first" and "second" are used only to distinguish one component from another component, and are not used to limit the components, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0018] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the scope of 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 dictates otherwise. The term "and / or" used in this disclosure means that one of the associated listed items may be included, or any and all possible combinations of two or more of them. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0019] The present disclosure is described with respect to a wireless communication network or wireless communication system, and operations performed in the wireless communication network may be performed in a process in which a device (e.g., a base station) that manages the wireless communication network controls the network and transmits or receives signals, or in a process in which a terminal coupled to the wireless network transmits or receives signals to or between the network.

[0020] In this disclosure, transmitting or receiving a channel includes transmitting or receiving information or signals on that channel. For example, transmitting a control channel means transmitting control information or signals on the control channel. Similarly, transmitting a data channel means transmitting data information or signals on the data channel.

[0021] 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, a transmitter may be a part of the base station, and a receiver may be a part of the terminal. In the uplink, a transmitter may be a part of the terminal, and a receiver may be a part of the base station. The base station may be expressed as a first communication device, and the terminal may be expressed as a second communication device. A base station (BS) may be replaced with terms such as a fixed station, Node B, eNB (evolved-NodeB), gNB (Next Generation NodeB), BTS (base transceiver system), access point (AP), network (5G network), AI (Artificial Intelligence) system / module, RSU (road side unit), robot, drone (UAV: Unmanned Aerial Vehicle), AR (Augmented Reality) device, VR (Virtual Reality) device, etc. In addition, a terminal may be fixed or mobile, and may be replaced with terms such as User Equipment (UE), Mobile Station (MS), user terminal (UT), Mobile Subscriber Station (MSS), Subscriber Station (SS), Advanced Mobile Station (AMS), Wireless terminal (WT), Machine-Type Communication (MTC) device, Machine-to-Machine (M2M) device, Device-to-Device (D2D) device, vehicle, road side unit (RSU), robot, Artificial Intelligence (AI) module, drone (UAV: Unmanned Aerial Vehicle), Augmented Reality (AR) device, Virtual Reality (VR) device, etc.

[0022] The following technologies may be used for various wireless access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, etc. CDMA may be implemented by radio technologies such as Universal Terrestrial Radio Access (UTRA) and CDMA2000. TDMA may be implemented by radio technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented by radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), etc. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (registered trademark) (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-A (Advanced) / LTE-A pro is an evolved version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A / LTE-A pro.

[0023] For clarity of explanation, the following description will be based on a 3GPP communication system (e.g., LTE-A, NR), but the technical idea of ​​the present disclosure is not limited thereto. LTE refers to technology after 3GPP TS (Technical Specification) 36.xxx Release 8. In detail, LTE technology after 3GPP TS 36.xxx Release 10 is called LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 is called LTE-A pro. 3GPP NR refers to technology after TS 38.xxx Release 15. LTE / NR may be called a 3GPP system. "xxx" refers to a standard document detail number. LTE / NR may be called a 3GPP system. For background technology, terms, abbreviations, etc. used in the description of the present disclosure, reference may be made to matters described in standard documents published before the present disclosure. For example, the following documents may be referenced.

[0024] In 3GPP LTE, reference can 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 (general description), and TS 36.331 (radio resource control).

[0025] For 3GPP NR, reference can be made 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 (General description of NR and NG-RAN (New Generation-Radio Access Network)), and TS 38.331 (Radio resource control protocol standard).

[0026] The following terminology abbreviations may be used in this disclosure:

[0027] - BM: Beam management

[0028] - CQI: channel quality indicator

[0029] - CRI: channel state information- reference signal resource indicator

[0030] - CSI: channel state information

[0031] - CSI-IM: channel state information-interference measurement

[0032] - CSI-RS: Channel state information-reference signal

[0033] - DMRS: Demodulation Reference Signal

[0034] - FDM: Frequency division multiplexing

[0035] - FFT: Fast Fourier transform

[0036] - IFDMA: Interleaved frequency division multiple access

[0037] - IFFT: inverse fast Fourier transform

[0038] - L1-RSRP: Layer 1 reference signal received power

[0039] - L1-RSRQ: Layer 1 reference signal received quality

[0040] - MAC: medium access control

[0041] - NZP: non-zero power

[0042] - OFDM: Orthogonal frequency division multiplexing

[0043] - PDCCH: physical downlink control channel

[0044] - PDSCH: physical downlink shared channel

[0045] - PMI: Precoding matrix indicator

[0046] - RE: resource element

[0047] - RI: Rank indicator

[0048] - RRC: Radio resource control

[0049] - RSSI: received signal strength indicator

[0050] - Rx: Reception

[0051] - QCL: quasi co-location

[0052] - SINR: signal to interference and noise ratio

[0053] - SSB (or SS / PBCH block): Synchronization signal block (including primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH))

[0054] - TDM: time division multiplexing

[0055] - TRP: transmission and reception point

[0056] - TRS: Tracking reference signal

[0057] - Tx: transmission

[0058] - UE: User Equipment

[0059] - ZP: Zero power

[0060] System in general

[0061] As more communication devices require larger communication capacity, the need for improved mobile broadband communication compared to existing radio access technology (RAT) is emerging. Massive MTC (Machine Type Communications), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues considered in next-generation communication. In addition, communication system design considering reliability and latency-sensitive services / terminals is also being discussed. Thus, the introduction of next-generation RATs considering eMBB (enhanced mobile broadband communication), Mmtc (massive MTC), URLLC (Ultra-Reliable and Low Latency Communication), etc. is being discussed, and for convenience in this disclosure, the technology is referred to as NR. NR is an expression representing an example of 5G RAT.

[0062] New RAT systems including NR use an OFDM transmission scheme or a similar transmission scheme. The new RAT system may follow OFDM parameters different from those of LTE. Or, the new RAT system may follow the existing LTE / LTE-A numerology but support a larger system bandwidth (e.g., 100 MHz). Or, one cell may support multiple numerologies. That is, terminals operating with different numerologies may coexist in one cell.

[0063] A numerology corresponds to a subcarrier spacing in the frequency domain. Different numerologies can be defined by scaling the reference subcarrier spacing by an integer N.

[0064] FIG. 1 illustrates the structure of a wireless communication system to which the present disclosure can be applied.

[0065] Referring to FIG. 1, the NG-RAN is composed of gNBs that provide an NG-Radio Access (NG-RA) user plane (i.e., a new access stratum (AS) sublayer / Packet Data Convergence Protocol (PDCP) / Radio Link Control (RLC) / MAC / PHY) and control plane (RRC) protocol termination for the UE. The gNBs are interconnected via an Xn interface. The gNBs are also connected to a New Generation Core (NGC) via an NG interface. More specifically, the gNBs are connected to an Access and Mobility Management Function (AMF) via an N2 interface and to a User Plane Function (UPF) via an N3 interface.

[0066] FIG. 2 illustrates a frame structure in a wireless communication system to which the present disclosure can be applied.

[0067] The NR system can support multiple numerologies, where the numerology may be defined by subcarrier spacing and cyclic prefix (CP) overhead. In this case, the multiple subcarrier spacing may be derived by scaling the base (reference) subcarrier spacing by an integer N (or μ). In addition, the numerology used may be selected independently of the frequency band, although it is assumed that very low subcarrier spacing is not used at very high carrier frequencies. In addition, various frame structures with multiple numerologies may be supported in the NR system.

[0068] The following describes OFDM numerologies and frame structures that can be considered in the NR system. Multiple OFDM numerologies supported in the NR system may be defined as shown in Table 1 below.

[0069] [Table 1]

[0070] NR supports multiple numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports a wide area in a traditional cellular band, when the SCS is 30 kHz / 60 kHz, it supports dense urban areas, lower latency, and wider carrier bandwidth, and when the SCS is 60 kHz or higher, it supports a bandwidth larger than 24.25 GHz to overcome phase noise. The NR frequency band is defined as two types of frequency ranges (FR1, FR2). FR1 and FR2 may be configured as shown in Table 2 below. Also, FR2 can mean millimeter wave (mmW).

[0071] [Table 2]

[0072] In relation to the frame structure in the NR system, the sizes of the various fields in the time domain are T c =1 / (Δf max N f ) where Δf max =480 10 3 Hz and N f= 4096. Downlink and uplink transmissions are f =1 / (Δf max N f / 100)·T c The radio frame is organized into radio frames each having a duration of T sf =(Δf max N f / 1000)·T c In this case, there may be one set of frames for the uplink and one set of frames for the downlink. Also, the transmission from the terminal in the uplink frame number i starts T TA =(N TA +N TA,offset )T c For a subcarrier spacing configuration μ, a slot is allocated within a subframe. s μ ∈{0,...,N slot subframe,μ -1}, and n s,f μ ∈{0,...,N slot frame,μ -1}. A slot is numbered in increasing order. symb slot It consists of N consecutive OFDM symbols. symb slot is determined by the CP. s μ The start of OFDM symbol n s μ N symb slotNot all terminals can transmit and receive at the same time, which means that not all OFDM symbols in a downlink slot or uplink slot can be used. Table 3 shows the number of OFDM symbols per slot (N symb slot ), the number of slots per radio frame (N slot frame,μ ), the number of slots per subframe (N slot subframe,μ ), and Table 4 shows 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.

[0073] [Table 3]

[0074] [Table 4]

[0075] FIG. 2 is an example when μ=2 (SCS is 60 kHz), and referring to Table 3, one subframe can include four slots. One subframe={1, 2, 4} slots shown in FIG. 2 is an example, and the number of slots that can be included in one subframe is defined as shown in Table 3 or Table 4. Also, a mini-slot can include 2, 4, or 7 symbols, or more or less symbols. In relation to physical resources in an NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, and the like may be considered.

[0076] The physical resources that can be considered in the NR system will be specifically described below. First, in relation to antenna ports, the antenna ports are defined such that a channel on which a symbol on an antenna port is carried can be inferred from a channel on which another symbol on the same antenna port is carried. If the large-scale property of a channel on which a symbol on one antenna port is carried can be inferred from a channel on which a symbol on the other antenna port is carried, the two antenna ports are said to be in a quasi co-located (QC / QCL) relationship. Here, the large-scale property includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

[0077] FIG. 3 illustrates a resource grid in a wireless communication system to which the present disclosure can be applied.

[0078] Referring to FIG. 3, the resource grid is divided into N RB μ N sc RB Each subframe consists of 14·2 subcarriers. μ In the present embodiment, the OFDM symbol is used as an example, but is not limited to, an OFDM symbol. RB μ N sc RB One or more resource grids consisting of subcarriers and two μ N symb (μ) OFDM symbols, where N RB μ ≦N RB max,μ The above NRB max,μ represents the maximum transmission bandwidth, which may vary not only with numerology but also between uplink and downlink. In this case, one resource grid may be set for μ and antenna port p. Each element of the resource grid for μ and antenna port p is called a resource element, and is represented by an index pair: JPEG2025514962000006.jpg617, where k=0,...,N RB μ N sc RB -1 is the index in the frequency domain, JPEG2025514962000007.jpg677 represents the position of the symbol within a subframe. When indicating a resource element in a slot, the index pair (k,l) is used.

[0079] where l=0,...,N symb μ μ and the resource element for antenna port p. JPEG2025514962000008.jpg617 is a complex value JPEG2025514962000009.jpg811. If there is no risk of confusion or if a specific antenna port or numerology is not specified, the indexes p and μ may be dropped, so that the complex value is JPEG2025514962000010.jpg1130. Also, a resource block (RB) is N sc RB = 12 consecutive subcarriers.

[0080] Point A serves as a common reference point for the resource block grid and is obtained as follows:

[0081] - offsetToPointA for the primary cell (PCell) downlink indicates the frequency offset between point A and the lowest subcarrier of the lowest resource block that overlaps with the SS / PBCH block used by the terminal for initial cell selection. It is expressed in resource block units assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2.

[0082] - absoluteFrequencyPointA indicates the frequency-location of point A expressed as in ARFCN (absolute radio-frequency channel number).

[0083] Common resource blocks are numbered from 0 upwards in the frequency domain for a subcarrier spacing setting μ. The center of subcarrier 0 of common resource block 0 for a subcarrier spacing setting μ coincides with 'point A'. Common resource block number n CRB μ The relationship between k, l and the resource element (k, l) for the subcarrier spacing setting μ is given by the following Equation 1.

[0084]

number

[0085] In Equation 1, k is defined relative to point A such that k=0 corresponds to the subcarrier centered at point A. A physical resource block is a number ranging from 0 to N within a bandwidth part (BWP). BWP,i size,μ The numbering is from -1 to i, where i is the number of the BWP. PRB and common resource block n CRB The relationship between is given by Equation 2 below.

[0086]

number

[0087] N BWP,i start,μ is the common resource block where the BWP starts relative to common resource block 0.

[0088] Fig. 4 illustrates a physical resource block in a wireless communication system to which the present disclosure can be applied, and Fig. 5 illustrates a slot structure in a wireless communication system to which the present disclosure can be applied.

[0089] 4 and 5, a slot includes a number of symbols in the time domain. For example, in the general CP, one slot includes seven symbols, while in the extended CP, one slot includes six symbols.

[0090] A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) is defined as multiple consecutive (physical) resource blocks in the frequency domain and may correspond to one numerology (e.g., SCS, CP length, etc.). A carrier may include up to N (e.g., 5) BWPs. Data communication is performed in the activated BWPs, and only one BWP may be activated for one terminal. Each element in the resource grid is called a resource element (RE), and one complex symbol may be mapped to it.

[0091] The NR system may support up to 400 MHz per component carrier (CC). If a terminal operating in such a wideband CC always operates with the radio frequency (RF) chip for the entire CC turned on, the terminal battery consumption may increase. Alternatively, considering various use cases (e.g., eMBB, URLLC, Mmtc, V2X, etc.) operating in one wideband CC, different numerologies (e.g., subcarrier spacing, etc.) may be supported for each frequency band in the CC. Alternatively, the capability for maximum bandwidth may differ for each terminal. In consideration of this, the base station may instruct the terminal to operate only in a part of the bandwidth rather than the entire bandwidth of the wideband CC, and the part of the bandwidth is defined as a bandwidth part (BWP) for convenience. The BWP may be composed of continuous RBs on the frequency axis and may correspond to one numerology (e.g., subcarrier spacing, CP length, slot / minislot interval).

[0092] Meanwhile, the base station can set multiple BWPs even within one CC set in the terminal. For example, a BWP occupying a relatively small frequency region can be set in the PDCCH monitoring slot, and the PDSCH indicated by the PDCCH can be scheduled on a larger BWP. Alternatively, when UEs are concentrated in a specific BWP, other BWPs can be set in some terminals for load balancing. Alternatively, in consideration of frequency domain inter-cell interference cancellation between adjacent cells, a part of the spectrum of the entire bandwidth can be excluded and both BWPs can be set in the same slot. That is, the base station can set at least one DL / UL BWP in the terminal associated with the wideband CC. The base station can activate at least one DL / UL BWP among the DL / UL BWPs set at a specific time (by L1 signaling, MAC CE (Control Element), RRC signaling, etc.). Also, the base station may instruct switching to another configured DL / UL BWP (by L1 signaling, MAC CE, RRC signaling, etc.). Or, the base station may switch to a predetermined DL / UL BWP when a timer value expires on a timer basis. In this case, the activated DL / UL BWP is defined as an active DL / UL BWP. However, in a situation where the UE is performing an initial access process or before an RRC connection is set up, the UE may not be able to receive the configuration for the DL / UL BWP. In such a situation, the DL / UL BWP assumed by the UE is defined as an initially active DL / UL BWP.

[0093] FIG. 6 illustrates examples of physical channels used in a wireless communication system to which the present disclosure can be applied, and a general signal transmission / reception method using the physical channels.

[0094] 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. Information transmitted and received between the base station and the terminal includes data and various control information, and various physical channels exist depending on the type / purpose of the information they transmit and receive.

[0095] When a terminal is powered on or newly enters a cell, the terminal performs an initial cell search operation such as synchronizing with a base station (S601). To this end, the terminal receives a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as a cell identifier (ID). After that, the terminal receives a physical broadcast channel (PBCH) from the base station to obtain broadcast information within the cell. Meanwhile, the terminal can receive a downlink reference signal (DL RS) during the initial cell search stage to check the downlink channel state.

[0096] After completing the initial cell search, the terminal receives a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) based on the information carried on the PDCCH, and can obtain more specific system information (S602).

[0097] Meanwhile, when the terminal first connects to the base station or has no radio resources for signal transmission, the terminal can perform a random access procedure (RACH: Random Access Procedure) to the base station (steps S603 to S606). To this end, the terminal can transmit a specific sequence as a preamble on a physical random access channel (PRACH: Physical Random Access Channel) (S603 and S605) and receive a response message to the preamble on a PDCCH and a corresponding PDSCH (S604 and S606). In the case of a contention-based RACH, a contention resolution procedure can also be performed.

[0098] After performing the above-mentioned procedures, the terminal can then perform PDCCH / PDSCH reception (S607) and Physical Uplink Shared Channel (PUSCH) / Physical Uplink Control Channel (PUCCH) transmission (S608) as a general uplink / downlink signal transmission procedure. In particular, the terminal receives Downlink Control Information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and has different formats depending on its purpose.

[0099] Meanwhile, control information that a terminal transmits to a base station in an uplink or that the terminal receives from a base station includes downlink / uplink ACK / NACK (Acknowledgement / Non-Acknowledgement) signals, CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indicator), etc. In a 3GPP LTE system, a terminal can transmit the above-mentioned control information such as CQI / PMI / RI in a PUSCH and / or a PUCCH.

[0100] Table 5 shows an example of a DCI format in an NR system.

[0101] [Table 5]

[0102] Referring to Table 5, DCI formats 0_0, 0_1, and 0_2 may include resource information related to PUSCH scheduling (e.g., UL / SUL (Supplementary UL), frequency resource allocation, time resource allocation, frequency hopping, etc.), transport block (TB) related information (e.g., MCS (Modulation Coding and Scheme), NDI (New Data Indicator), RV (Redundancy Version), etc.), HARQ (Hybrid- Automatic Repeat and request) related information (e.g., process number, DAI (Downlink Assignment Index), PDSCH-HARQ feedback timing, etc.), multiple antenna related information (e.g., DMRS sequence initialization information, antenna port, CSI request, etc.), and power control information (e.g., PUSCH power control, etc.), and the control information included in each of the DCI formats may be predefined.

[0103] DCI format 0_0 is used for scheduling PUSCH in one cell. Information included in DCI format 0_0 is CRC (cyclic redundancy check) scrambled by C-RNTI (Cell RNTI: Cell Radio Network Temporary Identifier), CS-RNTI (Configured Scheduling RNTI), or MCS-C-RNTI (Modulation Coding Scheme Cell RNTI) and transmitted.

[0104] DCI format 0_1 ​​is used to indicate to a terminal the scheduling of one or more PUSCHs in one cell or downlink feedback information of a configured grant (CG). Information included in DCI format 0_1 ​​is CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI (Semi-Persistent CSI RNTI), or MCS-C-RNTI and transmitted.

[0105] DCI format 0_2 is used for scheduling the PUSCH in one cell. Information included in DCI format 0_2 is CRC scrambled by the C-RNTI, CS-RNTI, SP-CSI-RNTI, or MCS-C-RNTI and transmitted.

[0106] Next, DCI formats 1_0, 1_1, and 1_2 may include resource information related to PDSCH scheduling (e.g., frequency resource allocation, time resource allocation, VRB (virtual resource block)-PRB (physical resource block) mapping, etc.), transmission block (TB) related information (e.g., MCS, NDI, RV, etc.), HARQ related information (e.g., process number, DAI, PDSCH-HARQ feedback timing, etc.), multiple antenna related information (e.g., antenna port, TCI (transmission configuration indicator), SRS (sounding reference signal) request, etc.), PUCCH related information (e.g., PUCCH power control, PUCCH resource indicator, etc.), and the control information included in each of the DCI formats may be pre-defined.

[0107] DCI format 1_0 is used for scheduling the PDSCH in one DL cell. Information included in DCI format 1_0 is CRC scrambled by the C-RNTI, CS-RNTI, or MCS-C-RNTI and transmitted.

[0108] DCI format 1_1 is used for scheduling the PDSCH in one cell. Information included in DCI format 1_1 is CRC scrambled by the C-RNTI, CS-RNTI, or MCS-C-RNTI and transmitted.

[0109] DCI format 1_2 is used for scheduling the PDSCH in one cell. Information included in DCI format 1_2 is CRC scrambled by the C-RNTI, CS-RNTI, or MCS-C-RNTI and transmitted.

[0110] V2X (vehicle-to-everything) / Sidelink (SL) communication

[0111] FIG. 7 shows a procedure for performing V2X or SL communication in a transmission mode in a wireless communication system to which the present disclosure can be applied.

[0112] The embodiment of Fig. 7 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. Hereinafter, for convenience of description, 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.

[0113] For example, Fig. 7(a) illustrates a UE operation associated with LTE transmission mode 1 or LTE transmission mode 3. Or, for example, Fig. 7(a) illustrates a UE operation associated with NR resource allocation mode 1. For example, LTE transmission mode 1 may be applied to general SL communication, and LTE transmission mode 3 may be applied to V2X communication.

[0114] For example, FIG. 7(b) illustrates UE operation associated with LTE transmission mode 2 or LTE transmission mode 4. Or, for example, FIG. 7(b) illustrates UE operation associated with NR resource allocation mode 2.

[0115] Referring to Figure 7 (a), in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, a base station may schedule SL resources to be used by a UE for SL transmission (S8000). For example, the base station may transmit information related to SL resources and / or information related to UL resources to a 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.

[0116] For example, the first UE may receive information related to dynamic grant (DG) resources and / or information related to configured grant (CG) resources from the base station. For example, the CG resources may include CG type 1 resources or CG type 2 resources. In the present disclosure, the DG resources may be resources that the base station configures / assigns to the first UE using DCI. In the present disclosure, the CG resources may be (periodic) resources that the base station configures / assigns to the first UE using 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 activation or release of the CG resources to the first UE.

[0117] The first UE may transmit a PSCCH (eg, Sidelink Control Information (SCI) or 1st-stage SCI) to the second UE based on the resource scheduling (S8010).

[0118] The first UE may transmit a PSSCH (eg, a 2nd-stage SCI, a MAC protocol data unit (PDU), data, etc.) associated with the PSCCH to the second UE (S8020).

[0119] The first UE may receive a PSFCH associated with the PSCCH / PSSCH from the second UE (S8030). For example, HARQ feedback information (e.g., NACK information or ACK information) may be received from the second UE on the PSFCH.

[0120] The first UE may transmit / report HARQ feedback information to the base station on a PUCCH or a PUSCH (S8040). For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on HARQ feedback information received from the second UE. For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on a pre-configured rule. For example, the DCI may be DCI for SL scheduling. For example, the format of the DCI may be DCI format 3_0 or DCI format 3_1.

[0121] Referring to FIG. 7(b), in LTE transmission mode 2, LTE transmission mode 4, or NR resource allocation mode 2, the UE can determine SL transmission resources from SL resources configured by the base station / network or preconfigured SL resources. For example, the configured SL resources or preconfigured SL resources may be a resource pool. For example, the UE can autonomously select or schedule resources for SL transmission. For example, the UE can select resources by itself from a configured resource pool to perform SL communication. For example, the UE can perform sensing and resource (re)selection procedures and select resources by itself within a selection window. For example, the sensing may be performed on a sub-channel basis.

[0122] The first UE that has selected a resource from the resource pool may transmit a PSCCH (eg, an SCI or a 1st-stage SCI) to the second UE using the resource (S8010).

[0123] The first UE may transmit a PSSCH (eg, a 2nd-stage SCI, a MAC PDU, data, etc.) associated with the PSCCH to the second terminal (S8020).

[0124] The first UE may receive a PSFCH associated with the PSCCH / PSSCH from the second UE (S8030).

[0125] 7(a) or 7(b), for example, the first UE may transmit an SCI to the second UE on a PSCCH. Or, for example, the first UE may transmit two consecutive SCIs (e.g., 2-stage SCIs) to the second UE on a PSCCH and / or a PSSCH. In this case, the second UE may decode the two consecutive SCIs (e.g., 2-stage SCIs) to receive the PSSCH from the first UE. In the present disclosure, the SCI transmitted on the PSCCH may be referred to as a first SCI, a first SCI, a first-stage SCI, or a 1st-stage SCI format, and the SCI transmitted on the PSSCH may be referred to as a second SCI, a second SCI, a second-stage SCI, or a 2nd-stage SCI format. For example, the 1st-stage SCI format may include SCI format 1-A, and the 2nd-stage SCI format may include SCI format 2-A and / or SCI format 2-B.

[0126] 7(a) or 7(b), in step S8030, the first UE may receive a PSFCH based on the description to be described later. For example, the first UE may determine a PSFCH resource based on the description to be described later, and the second UE may transmit HARQ feedback to the first UE on the PSFCH resource.

[0127] This document describes the UE procedures for reporting HARQ-ACK on the sidelink as specified in TS 38.213.

[0128] The UE may be instructed by an SCI format that schedules PSSCH reception to transmit a PSFCH including HARQ-ACK information in response to the PSSCH reception. The UE provides HARQ-ACK information including an ACK or a NACK or only a NACK.

[0129] The UE may be provided with the number of slots in a resource pool during a PSFCH transmission occasion resource period by the sl-PSFCH-Period. If the number of slots is 0, the UE's PSFCH transmission is disabled in the resource pool.

[0130] The UE is k mod N PSSCH PSFCH = 0, then slot t' k SL (0≦k <T’ max ) contains the PSFCH transmission opportunity resource, where t' k SL is defined in TS 38.214, and T' max is the number of slots belonging to the resource pool within 10240 msec based on TS 38.214, and N PSSCH PSFCH is provided by sl-PSFCH-Period.

[0131] The UE may be instructed by higher layers not to transmit a PSFCH containing HARQ-ACK information in response to receiving a PSSCH.

[0132] The UE provides HARQ-ACK information in a PSFCH transmission in the resource pool if the UE receives a PSSCH in the resource pool and the HARQ feedback enabled / disabled indicator field in the associated SCI format 2-A / 2-B / 2-C has value 1. The UE transmits the PSFCH in the first slot of the resource pool after the last slot of the PSSCH reception that includes a PSFCH resource and that corresponds to at least a number of slots provided by sl-MinTimeGapPSFCH.

[0133] The UE selects M DMA channels in the resource pool for transmission of the PSFCH including the HARQ-ACK information in the physical resource block (PRB) of the resource pool. PRB,set PSFCH A set of PRBs is provided by sl-PSFCH-RB-Set. The UE selects M PRBs in the resource pool for PSFCH transmission including conflict information in the PRBs of the resource pool. PRB,set PSFCH A set of PRBs may be provided by sl-RB-SetPSFCH. The UE expects that different PRBs are configured (pre-configured) for collision information and HARQ-ACK information. SUBCH Number of subchannels and N PSSCH PSFCH For a number of PSSCH slots associated with the PSFCH slot that is less than or equal to the number of PSSCH slots associated with the PSFCH slot, the UE may select M PRB,set PSFCH PRB to [(i+j N PSSCH PSFCH )·M subch,slot’ PSFCH (i+1+j N PSSCH PSFCH )·M subch,slot PSFCH -1] PRBs are assigned to slot i, where subch,slot PSFCH =M PRB,set PSFCH / (N subch N PSSCH PSFCH ), 0≦i <N PSSCH PSFCH , 0≦j <N subch where the allocation starts with increasing i and continues with increasing j. The UE PRB,set PSFCH is N subch N PSSCH PSFCH is expected to be a multiple of .

[0134] The UE shall determine the number of PSFCH resources that can be used for multiplexing HARQ-ACK or collision information in a PSFCH transmission based on the indication by sl-PSFCH-CandidateResourceType as follows: PRB,CS PSFCH =N type PSFCH M subch,slot PSFCH N CS PSFCH Here, N CS PSFCH is the number of cyclic shift pairs for the resource pool provided by sl-NumMuxCS-Pair.

[0135] - If sl-PSFCH-CandidateResourceType is set to startSubCH, N type PSFCH = 1, and M subch,slot PSFCH This PRB is associated with the starting subchannel of the PSSCH.

[0136] - If sl-PSFCH-CandidateResourceType is set to allocSubCH, N type PSFCH =N subch PSSCH and N subch PSSCH M subch,slot PSFCH PRBs are N subch PSSCH associated with sub-channels.

[0137] - For collision information, the PSSCH is determined based on sl-PSFCH-Occasion.

[0138] The PSFCH resource is N type PSFCH M subch,slot PSFCH PRBs, first in ascending order of PRB index, then N CS PSFCHThe cyclic shift pairs are indexed in ascending order of the cyclic shift pair indexes.

[0139] The UE determines whether the PSFCH resource index for transmitting the PSFCH including HARQ-ACK information or collision information in response to the PSSCH reception is (P ID +M ID )modR PRB,CS PSFCH Here, P ID is a physical layer source ID provided by SCI format 2-A / 2-B / 2-C for scheduling PSSCH reception or reserving resources for collision information provided by other UEs. If the UE detects SCI format 2-A with a cast type indicator field value of '01' for HARQ-ACK information, M ID is the identity of the UE receiving the PSSCH indicated by the higher layer, otherwise, M ID is 0. For collision information, M ID is 0.

[0140] For a PSFCH transmission including HARQ-ACK information or collision information, the UE calculates a cyclic shift value α from the cyclic shift pair index corresponding to the PSFCH resource index using Table 6 below and N CS PSFCH From this, the m0 value is determined.

[0141] Table 6 illustrates a set of cyclic shift pairs.

[0142] [Table 6]

[0143] For a PSFCH transmission including HARQ-ACK information, if the UE detects SCI format 2-A or SCI format 2-C having a cast type indicator field value of '01' or '10', the UE calculates the cyclic shift value α as shown in Table 7 below. cs If the UE detects SCI format 2-B or 2-A having a cast type indicator field value of '11', m is set as shown in Table 8 below. cs For a PSFCH transmission that includes collision information, the UE determines the value of m cs The UE determines a cyclic shift from the cyclic shift pair to a sequence used for PSFCH transmission. Table 7 illustrates a 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 an ACK or NACK.

[0144] [Table 7]

[0145] Table 8 illustrates a mapping of cyclic shifts of sequences and HARQ-ACK information bit values ​​for PSFCH transmission from a cyclic shift pair when the HARQ-ACK information includes only NACK.

[0146] [Table 8]

[0147] Table 9 illustrates a mapping from cyclic shift pairs to cyclic shifts of sequences and collision information bit values ​​for PSFCH transmission.

[0148] [Table 9]

[0149] FIG. 8 illustrates a cast type for V2X or SL communication in a wireless communication system to which the present disclosure can be applied. The embodiment of FIG. 8 may be combined with various embodiments of the present disclosure. Referring to FIG. 8, FIG. 8(a) illustrates a broadcast type SL communication, FIG. 8(b) illustrates a unicast type SL communication, and FIG. 8(c) illustrates a group-cast type SL communication. In the case of the unicast type SL communication, a UE can perform one-to-one communication with another UE. In the case of the group-cast type SL communication, a UE can perform SL communication with one or more UEs in a group to which the UE belongs. In various embodiments of the present disclosure, the SL group-cast communication may be referred to as SL multicast communication, SL one-to-many communication, etc.

[0150] The Hybrid Automatic Repeat Request (HARQ) procedure will be described below.

[0151] For example, SL HARQ feedback may be enabled for unicast. In this case, in a non-Code Block Group (non-CBG) operation, if a 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 transmit a HARQ-ACK to the transmitting UE. On the other hand, if the receiving UE decodes a PSCCH targeted to the receiving UE but fails to successfully decode a transport block associated with the PSCCH, the receiving UE may generate a NACK. The receiving UE may then transmit a NACK to the transmitting UE.

[0152] Also, for example, SL HARQ feedback may be enabled for groupcast. For example, in non-CBG operation, two HARQ feedback options may be supported for groupcast.

[0153] (1) Groupcast Option 1: After a receiving UE decodes a PSCCH targeted to the receiving UE, if the receiving UE fails to decode a transport associated with the PSCCH, the receiving UE can send a NACK to the transmitting UE on a PSFCH. On the other hand, 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 does not need to send an ACK to the transmitting UE.

[0154] (2) Groupcast Option 2: After a receiving UE decodes a PSCCH targeted to the receiving UE, if the receiving UE fails to decode a transmission block associated with the PSCCH, the receiving UE can send a NACK to the transmitting UE on the PSFCH. And, if the receiving UE decodes a PSCCH targeted to the receiving UE and the receiving UE successfully decodes a transmission block associated with the PSCCH, the receiving UE can send an ACK to the transmitting UE on the PSFCH.

[0155] For example, when groupcast option 1 is used for SL HARQ feedback, all UEs performing groupcast communication can share the PSFCH resource, e.g., UEs belonging to the same group can use the same PSFCH resource to transmit HARQ feedback.

[0156] For example, when groupcast option 2 is used for SL HARQ feedback, each UE performing groupcast communication can use different PSFCH resources for HARQ feedback transmission, for example, UEs belonging to the same group can transmit HARQ feedback using different PSFCH resources.

[0157] In this disclosure, an ACK may be referred to as a HARQ-ACK, ACK information, or positive-ACK information, and a NACK may be referred to as a HARQ-NACK, NACK information, or negative-ACK information.

[0158] The sidelink grant may be configured semi-persistently by the RRC or dynamically received from the PDCCH selected autonomously by the MAC entity, which may have a sidelink grant in the active SL BWP to determine the set of PSCCH periods in which the SCI transmissions occur and the set of PSSCH periods in which the SL-SCH transmissions associated with the SCI occur.

[0159] When the MAC entity is configured in sidelink resource allocation mode 1, it may take action based on each PDCCH opportunity and on each grant received for that PDCCH opportunity.

[0160] Terminal / base station behavior for consecutive LBT failures in SL transmission

[0161] NR Unlicensed Spectrum (NR-U) refers to a mode that provides the technology necessary for cellular operators to integrate unlicensed spectrum into their wireless communication systems. NR-U enables full uplink and downlink operation in unlicensed spectrum.

[0162] In NR-U, uplink and downlink channel access depends on the LBT function. The terminal and / or base station may first sense the communication channel to determine whether there is any communication before transmitting. If the communication channel is a wideband unlicensed carrier, the NR-U channel sensing procedure may rely on sensing energy levels in multiple sub-bands of the communication channel. The base station may configure LBT parameters (e.g., type / duration, clear channel assessment parameters, etc.) for the terminal.

[0163] In NR-U, a terminal can determine when and where to transmit and receive based on the instructions of a channel occupancy time (COT) structure. The COT is composed of multiple slots, and each slot may be composed of a downlink resource, an uplink resource, or a flexible resource.

[0164] In an NR-U system, both contiguous and interlaced uplink resource allocations may be supported while observing regulations. In interlaced uplink resource allocation, the basic unit of resource allocation for NR unlicensed channels may be an interlace. For example, a single interlace may consist of 10 equally spaced resource blocks within a 20 MHz frequency bandwidth for 15 kHz subcarrier spacing.

[0165] A base station can operate in dynamic or semi-static channel access modes. In both channel access modes, the base station and terminals can apply Listen-Before-Talk (LBT) before transmitting in cells configured with shared spectrum channel access. When LBT is applied, the transmitter can listen / sense the channel and determine if the channel is free or busy, and can transmit only if it senses free on the channel.

[0166] NR radio access operating as a shared spectrum channel access can operate in various modes where a PCell, PSCell, or SCell can operate in the shared spectrum and the SCell may or may not be configured as an uplink.

[0167] The UE may detect / detect a consistent (or continuous) uplink LBT failure. If the physical layer performs an LBT procedure before transmission and reception, an LBT failure indication may be transmitted from the physical layer to a MAC entity. LBT failure detection may be performed for each BWP and may be performed based on all uplink transmissions within the BWP. When a consistent uplink LBT failure is detected in an SCell, the UE may report the detected LBT failure to the gNB (e.g., MN in the case of MCG, SN in the case of SCG) using a MAC CE in a serving cell different from the SCell in which the failure was detected.

[0168] If there are no resources available for transmitting the MAC CE, the UE may transmit a scheduling request (SR) (to the base station). If a sustained uplink LBT failure is detected in the SpCell, the UE may switch to another UL BWP with RACH resources configured in the cell, initiate RACH, and report the LBT failure using the MAC CE. If multiple UL BWPs are available for switching, which UL BWP the UE selects may depend on the UE implementation.

[0169] In the case of a PSCell, if a sustained uplink LBT failure is detected in all UL BWPs with configured RACH resources, the UE may declare an SCG RLF and report the failure to the MN using 'SCGFailureInformation'. In the case of a PCell, if an uplink LBT failure is detected in all UL BWPs with configured RACH resources, the UE may declare an RLF (radio link failure).

[0170] The channel access priority classes (CAPC) of the radio bearer and MAC CE may be fixed or configurable:

[0171] - Padding BSR and Recommended Bit Rate fixed as lowest priority for MAC CE;

[0172] - Fixed as highest priority for SRB(signaling radio bearer)0, SRB1, SRB3 and other MAC CEs;

[0173] - It may be set by the base station for SRB2 and DRB (data radio bearer).

[0174] When selecting CAPC for a DRB, the base station may take into consideration the 5QIs of all QoS flows multiplexed in the DRB, as well as fairness between various traffic types and transmissions.

[0175] Table 10 below can indicate which CAPC should be used for a certain standardized 5 QI (QoS identifier), i.e., which CAPC should be used for a given QoS flow. In Table 10, a lower CAPC value can mean a higher priority.

[0176] [Table 10]

[0177] Here, 5 QI may refer to a value used to identify the QoS requirements of a particular service or traffic flow. The 5 QI parameter may be used together with the CAP parameter to determine the priority level of a particular service or traffic flow. When performing Type 1 LBT for uplink TB transmission and when CAPC is not indicated in DCI, the terminal may select CAPC in the following manner:

[0178] - if only a MAC CE is included in the TB, the highest priority CAPC of that MAC CE is used;

[0179] - if a common control channel (CCCH) SDU (service data unit) is included in the TB, the CAPC with the highest priority is used;

[0180] - if a dedicated control channel (DCCH) SDU is included in the TB, the highest priority CAPC of the DCCH is used;

[0181] - Otherwise, the lowest priority CAPC of a logical channel whose MAC SDUs are multiplexed into the TB may be used.

[0182] If SL transmission is supported in an unlicensed band, the terminal may perform LBT for SL transmission. In a basic wireless communication system, the CAPC is not mapped to the next SL radio bearer and MAC CE. Therefore, there is a problem in that it is unclear how the terminal should perform a channel access procedure for SL transmission.

[0183] A sidelink signaling radio bearer (SL-SRB) for PC5-S messages (e.g., direct link establishment request) that are not protected for unicast of NR sidelink communication may be named SL-SRB0.

[0184] The SL-SRB of PC5-S messages that set PC5-S security (e.g., Direct Link Security Mode Command and Direct Link Security Mode Complete) may be named SL-SRB1.

[0185] The SL-SRB of a protected PC5-S message other than direct link security mode completion may be named SL-SRB2.

[0186] In the case of an NR sidelink U2N (UE-to-Network) relay, the sidelink signaling radio bearer for NR sidelink U2N relay-related discovery messages (e.g., announcement messages, request messages, and response messages) may be named SL-SRB4.

[0187] 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 name of the PC5 relay RLC channel for the remote UE's SRB0 message transmission may be SL-RLC0.

[0188] The sidelink RLC bearer for SRB1 RRC messages of a remote UE, such as “RRCResume”, “RRCReestablishment” and “RRCReconfigurationComplete” messages (in response to an “RRCReconfiguration” message containing “reconfigureWithSync” indicating reroute to an L2 U2N relay UE), may be named SL-RLC1.

[0189] 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.

[0190] For each unicast PC5-RRC connection, one sidelink SRB (i.e., SL-SRB0) may be used to transmit PC5-S messages before PC5-S security is configured. One sidelink SRB (i.e., SL-SRB1) may be used to transmit PC5-S messages to configure PC5-S security. One sidelink SRB (i.e., SL-SRB2) may be used to transmit PC5-S messages after protected PC5-S security is configured. One sidelink SRB (i.e., SL-SRB3) may be used to transmit protected PC5-RRC signals and may be transmitted only after PC5-S security is configured. For U2N relay operation, one sidelink SRB (i.e., SL-SRB4) may be used to transmit and receive NR sidelink discovery messages.

[0191] For unicast NR sidelink communications, AS security may be configured as integrity protection of PC5 signaling (SL-SRB1, SL-SRB2, and SL-SRB3) and user data (SL-DRB), and encryption of PC5 signaling (e.g., SL-SRB1, SL-SRB2, and SL-SRB3 for direct link security mode complete messages only) and user data (SL-DRB). Encryption and integrity protection algorithms and parameters for the PC5 unicast link may be exchanged by higher layer PC5-S messages and applied to the corresponding PC5-RRC connection in the AS.

[0192] When AS security is activated for an upper layer PC5 unicast link, all messages in SL-SRB2 and SL-SRB3 and / or user data in the SL-DRB of the PC5-RRC connection may be integrity protected and / or encrypted by PDCP.

[0193] When a key change is indicated at a higher layer for unicast NR sidelink communication, the terminal can reconfigure the PDCP entities of SL-SRB1, SL-SRB2, SL-SRB3 and SL-DRB in the PC5-RRC connection.

[0194] The following describes the operation of a terminal / base station when successive LBT failures occur for SL transmission.

[0195] The terminal can perform logical channel prioritization based on the CAPC value.

[0196] As an example, in the case of SL transmission for an SL grant with a CPAC value of 1, the terminal can select a destination for the logical channel to be mapped to, configure a TB, and transmit the TB using the SL grant.

[0197] As an example, when a terminal is configured with SL mode 1 (or SL resource allocation mode 1), the terminal can receive an SL grant in DCI format 3_0. In this case, the base station can indicate the CAPC value of the SL grant in DCI format 3_0.

[0198] As yet another example, when SL mode 2 (or SL resource allocation mode 2) is configured for a terminal, the CAPC value may be mapped based on each of the resource pools and / or logical channels.

[0199] When a resource pool and a CAPC value are mapped, the terminal can configure a TB by selecting a destination where a logical channel for the mapped CAPC can be set for the selected sidelink grant generated in the resource pool.

[0200] As yet another example, the CAPC value may be configured based on the logical channel. When a selected sidelink grant for a particular logical channel is generated, the terminal may apply the CAPC mapped to the selected sidelink grant. For the selected sidelink grant, the terminal may select a destination to which the logical channel for the mapped CAPC can be configured to configure a TB.

[0201] The CAPC for a logical channel may be mapped to the MAC CE type that the logical channel transmits, or the PQI value of the SL data, PC5-S message, PC5-RRC message, logical channel priority, and the like.

[0202] For convenience of explanation, a sidelink Tx (transmission) terminal is referred to as a first terminal, and a sidelink Rx (reception) terminal is referred to as a second terminal / third terminal in Fig. 9. Also, in Fig. 9, sidelink operation between the first terminal and the second terminal / third terminal can operate in an unlicensed band / spectrum or a shared spectrum.

[0203] FIG. 9 is a diagram illustrating a process in which a first terminal performs sidelink communication according to an embodiment of the present disclosure.

[0204] The first terminal may select a destination based on a channel access priority class (CAPC) value corresponding to a particular selected SL grant (S910), and may select at least one logical channel for the selected destination (S920).

[0205] As an example, based on the SL resource allocation mode 1 being configured, the first terminal may receive a selected SL grant in a DCI, and the first terminal may receive a CAPC value from the base station by the DCI including the specific selected SL grant.

[0206] As yet another example, based on SL resource allocation mode 2 being configured, the first terminal can generate a selected SL grant based on at least one SL resource pool configured from the base station (i.e., configuration information associated with at least one SL resource pool received from the base station).

[0207] Here, the CAPC value may be determined based on a logical channel corresponding to a particular selected SL grant. As yet another example, the CAPC value may correspond / map to a particular SL resource pool among at least one SL resource pool.

[0208] The first terminal can then select at least one logical channel based on the determined CAPC value for the particular selected SL grant.

[0209] Additionally or alternatively, the CAPC value may be indicated by sidelink control information (SCI) that triggers SL MAC CE or SL data to be transmitted on at least one logical channel.

[0210] And, based on the SL communication being a broadcast communication, the destination may include a specific service, based on the SL communication being a groupcast communication, the destination may include a specific terminal group, and based on the SL communication being a unicast communication, the destination may include a target terminal.

[0211] Information associated with the SL MAC CE or SL data transmitted on the at least one logical channel (eg, a PQI value of the SL data, etc.) may be mapped to a CAPC value corresponding to the at least one logical channel.

[0212] The first terminal may transmit at least one TB to at least one other terminal (eg, a target terminal or / and a terminal group) based on the selected at least one logical channel (S930).

[0213] That is, the first terminal can configure at least one TB based on the selected at least one logical channel, and transmit the at least one TB to at least one other terminal corresponding to the destination.

[0214] Specifically, the first terminal can generate at least one TB based on SL data corresponding to the selected at least one logical channel, and the first terminal can transmit the at least one TB to at least one other terminal by using a channel access procedure based on a CAPC value corresponding to the selected SL grant.

[0215] When an SL unicast connection (or a PC5-S direct connection for unicast or / and a PC5-S direct connection for groupcast) is established with a second terminal among at least one other terminal, the first terminal can transmit at least one TB to the second terminal via a PSSCH.

[0216] The method performed by the first terminal described in the example of FIG. 9 may be performed by the first device 100 of FIG.

[0217] For example, the one or more processors 102 of the first device 100 of FIG. 13 may be configured to select a destination based on a CAPC value corresponding to a particular selected SL grant. The one or more processors 102 may be configured to select at least one logical channel for the selected destination. The one or more processors 102 may transmit at least one TB to at least one other terminal via the one or more transceivers 106 based on the selected at least one logical channel.

[0218] Additionally, the one or more memories 104 of the first device 100 may store instructions for performing the method described in the example of FIG. 9 when executed by the one or more processors 102 .

[0219] FIG. 10 is a diagram for explaining a process in which a second terminal performs sidelink communication according to one embodiment of the present disclosure.

[0220] The second terminal can set up an SL unicast connection or an SL groupcast connection with the first terminal (S1010).

[0221] For example, the second terminal may transmit a message for an SL unicast connection (e.g., a message for a PC5-S direct connection for unicast) to the first terminal or receive the message from the first terminal, thereby allowing the second terminal to set up an SL unicast connection with the first terminal.

[0222] Additionally or alternatively, the second terminal can set up a groupcast connection with the first terminal. The second terminal can send a message for SL groupcast connection (e.g., a message for PC5-S direct connection to groupcast) to the first terminal or receive the message from the first terminal. This allows the second terminal to set up an SL groupcast connection with the first terminal.

[0223] The second terminal may receive at least one TB from the first terminal generated based on at least one logical channel corresponding to a destination associated with a CAPC value corresponding to a particular selected SL grant (S1020).

[0224] This allows the second terminal to transmit HARQ-ACK information for at least one TB to the first terminal via the physical sidelink feedback channel (S1030).

[0225] The method performed by the second terminal described in the example of FIG. 10 may be performed by the second device 200 of FIG.

[0226] For example, the one or more processors 202 of the second device 200 of FIG. 13 may establish an SL unicast or groupcast connection with the first terminal. The one or more processors 202 may be configured to receive from the first terminal, via the one or more transceivers 206, at least one TB generated based on at least one logical channel corresponding to a destination associated with a CAPC value corresponding to a particular selected SL grant. The one or more processors 202 may transmit HARQ-ACK information for the at least one TB to the first terminal on a PSFCH via the one or more transceivers 206.

[0227] Additionally, the one or more memories 204 of the second device 200 may store instructions for performing the method described in the example of FIG. 10 when executed by the one or more processors 202 .

[0228] In the following, with reference to FIG. 11, a SL transmission method using a channel access procedure based on CAPC according to one embodiment of the present disclosure will be described.

[0229] UE #1 may receive an RRC message for setting up a CAPC for an SL radio bearer and an SL MAC CE (S1110).

[0230] The CAPC of the SL radio bearer and the MAC CE may be fixed or configurable.

[0231] As an example, data on a sidelink control channel (SCCH) may be fixed as the highest priority (or the lowest priority) (e.g., depending on what signaling is carried on the SCCH) or may be set by an RRC message.

[0232] As an example, the SL CSI reporting MAC CE may be fixed as the highest priority (or the lowest priority) or configurable by an RRC message.

[0233] As an example, the SL Inter-UE Coordination Request MAC CE and the SL Inter-UE Coordination Reporting MAC CE may be fixed as the highest priority (or the lowest priority) or may be configurable by an RRC message.

[0234] As an example, the SL DRX Command MAC CE may be fixed as the highest priority (or the lowest priority) or configurable by an RRC message.

[0235] As an example, all sidelink traffic channel (STCH) data may be configurable via RRC messages.

[0236] As an example, padding may be fixed as the lowest priority.

[0237] An example of how CAPC values ​​are mapped to SL logical channels or SL MAC CEs for SL transmission may be as 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 set to 1.

[0238] [Table 11]

[0239] In the case of configurable CAPC, a terminal in RRC_IDLE or RRC_INACTIVE state may receive system information to configure CAPC for SL radio bearers and SL MAC CEs. As yet another example, in the case of configurable CAPC, a terminal in RRC_CONNECTED state may receive a dedicated RRC message to configure CAPC for SL radio bearers and SL MAC CEs. When out of network coverage, the terminal may use SL pre-configuration to determine CAPC for SL transmission. The system information, dedicated RRC message, or SL pre-configuration may configure CAPC for SL radio bearers and SL MAC CEs as shown in the table below.

[0240] As an example of the present disclosure, CAPC may be configured for each "SL-LogicalChannelConfig" (i.e., for each SL logical channel configuration). "SL-LogicalChannelConfig" is an RRC parameter (i.e., information element) used to configure SL logical channel parameters, and may be configured as shown in Table 12.

[0241] [Table 12]

[0242] As an example of the present disclosure, CAPC may be configured for each "SL-RLC-ChannelConfig" (i.e., for each "sl-RLC-ChannelID"). The "SL-RLC-ChannelConfig" may specify SL RLC bearer configuration information for a PC5 relay RLC channel between a L2 U2N (UE-to-Network) relay terminal and a L2 U2N remote UE, and may be configured as shown in Table 13.

[0243] [Table 13]

[0244] As an example of the present disclosure, CAPC may be set for each "sl-LogicalChannelIdentity" (i.e., for each logical channel ID). As shown in Table 14 below, "sl-LogicalChannelIdentity" may be included in "SL-LogicalChannelConfigPC5".

[0245] [Table 14]

[0246] As an example of the present disclosure, the CAPC may be set for each SL-PQFI (i.e., for each PC5 QoS flow identifier (PQFI)). As shown in Table 15, the SL-PQFI information may be included in the SL-PQFI setting information.

[0247] [Table 15]

[0248] As an example of the present disclosure, CAPC may be set for each period of "sl-LogicalChannelIdentiy." The "sl-LogicalChannelIdentiy" information may be configured as shown in Table 16.

[0249] [Table 16]

[0250] As an example of the present disclosure, CAPC may be configured per resource pool. As yet another example, CAPC may be configured per L2 (layer 2) destination ID or source ID and destination ID target. If system information, dedicated RRC message, or SL pre-configuration does not configure CAPC for an SL radio bearer, CAPC may be determined based on the PQI of the SL radio bearer. The PQI may be a special 5 QI. The PQI may be used as a reference for parameters that control QoS delivery for packets with PC5 QoS characteristics (i.e., PC5 reference point). Standardized PQI values ​​may be one-to-one mapped to standardized combinations of PC5 QoS characteristics.

[0251] For example, the mapping of one or more PQI values ​​to a particular CAPC may be specified according to the scheme described below.

[0252] When selecting the CAPC for a SLRB (SL Radio Bearer), the base station may take into account the PQIs of all QoS flows multiplexed in the DRB, as well as various traffic types and fairness among transmissions.

[0253] Table 17 below can indicate what CAPC should be used for a standardized PQI, i.e., what CAPC should be used for a given QoS flow, where a lower CAPC RKQT can mean a higher priority.

[0254] [Table 17]

[0255] If SL mode 1 is configured for the terminal, the terminal may receive DCI format 3_0 or DCI format 3_x, which may indicate a CAPC for the SL grant. The terminal that has received the DCI may perform SL transmission using Type 1 or Type 2 channel access procedure with the indicated CAPC. If SL mode 2 is configured for the terminal, when the terminal generates a selected sidelink grant for a logical channel having SL data or SL MAC CE, the terminal may select a resource pool that may be mapped to the logical channel of the SL data or SL MAC CE and determine a CAPC for SL transmission for the selected sidelink grant in the selected resource pool.

[0256] In this case, as an example, a CAPC or a SL MAC CE mapped to the SL data may be associated with the selected sidelink grant, or as yet another example, a CAPC mapped to the selected resource pool may be associated with the selected sidelink grant.

[0257] If SL mode 1 is configured for the terminal, when the terminal performs a type 1 LBT for SL transmission of TB on SL resources and no CAPC is indicated in the DCI to allocate SL resources; or

[0258] If SL mode 2 is configured for the terminal, when the terminal 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 CAPC for SL mode 2 is not indicated by the base station:

[0259] A terminal can select CAPC as follows:

[0260] If only SL MAC CE is included in the TB, the highest priority CAPC of that MAC CE is used;

[0261] If an SCCH SDU carrying PC5-S signaling is included in the TB, the highest priority CAPC is used; or

[0262] If an SCCH SDU carrying a PC5-RRC message is included in the TB, the highest priority CAPC of the SCCH carrying the PC5-RRC message is used;

[0263] If an SCCH or STCH SDU carrying an RRC message in SL-RLC0 is included in the TB, the highest priority CAPC of the SCCH or STCH carrying an RRC message in SL-RLC0 is used;

[0264] If the TB contains an SCCH or STCH SDU carrying an RRC message in SL-RLC1, the CAPC with the highest priority of the SCCH or STCH carrying an RRC message in SL-RLC1 is used; or

[0265] Otherwise, the lowest priority CAPC of the SL logical channel having MAC SDUs multiplexed in the TB may be used.

[0266] One or more of the above-mentioned methods for determining the CAPC for SL transmission may be used in the following steps.

[0267] In step S1120, UE #1 can perform LBT with the determined CAPC and establish a direct link with UE #2 for unicast services by exchanging PC5-S signaling with UE #2.

[0268] UE #1 can transmit the SCCH carrying the PC5-S message using Type 1 or Type 2 channel access procedure, together with the CAPC corresponding to the SCCH carrying the PC5-S message, which may also be used by UE #1 to transmit the SCI for scheduling the SCCH.

[0269] In step S1130, UE #1 can perform LBT with the determined CAPC and transmit PC5-S signaling to UE #2 and UE #3 for groupcast service (or broadcast service).

[0270] UE #1 can transmit a PSSCH carrying groupcast (or broadcast) signaling or data using a Type 1 or Type 2 channel access procedure together with a CAPC corresponding to a groupcast SL transmission (or broadcast SL transmission) (i.e., a CAPC corresponding to the cast-type).

[0271] Alternatively, in the case of SL transmission, the CAPC may be determined by the groupcast (or broadcast) destination. That is, the CAPC may correspond to the groupcast (or broadcast) target ID set by the system information, a dedicated RRC message, or pre-configuration. If the destination is not set by the RRC message, a default CAPC may be determined for the SL transmission. The CAPC may also be used for UE #1 to transmit the SCI that schedules the PSSCH.

[0272] A PC5-RRC connection may be established between UE #1 and UE #2 (S1140). UE #1 may perform LBT with the determined CAPC (S1150).

[0273] UE #1 may send a PC5-RRC message to UE #2 to configure a SL radio bearer and a MAC CE (S1160). In the PC5-RRC message, the CAPC may be configured for a specific SL radio bearer or a specific SL MAC CE.

[0274] Specifically, UE #1 can transmit the SCCH carrying the PC5-RRC message using a Type 1 or Type 2 channel access procedure, together with a CAPC corresponding to the SCCH carrying the PC5-RRC message, which may also be used by UE #1 to transmit the SCI for scheduling the SCCH.

[0275] UE #2 can perform LBT with CAPC determined based on the RRC message received from UE #1 (S1165). In step S1170, UE #2 can transmit a PSSCH carrying SL data of the SL-DRB to UE #1 after transmitting an SCI to UE #1.

[0276] UE #1 receives the SCI and PSSCH from UE #2, and can transmit an SL HARQ-ACK in response to the PSCCH transmission of the SL data of the SL-DRB to UE #2 (S1175).

[0277] Specifically, UE #2 can transmit to UE #1 a PSSCH carrying an SCI and SL data of an SL-DRB. UE #2 can transmit an SCI and a PSSCH carrying a TB including an STCH carrying SL data of an SL-DRB by using a Type 1 or Type 2 channel access procedure together with a CAPC corresponding to an STCH based on the CAPC set by UE #1 or the CAPC instructed / set by the gNB in ​​the above-mentioned step.

[0278] UE #2 can use the CAPC instructed / 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 may be instructed by DCI and PSSCH that allocates SL resources of SCI. In this case, UE #2 can use the CAPC instructed by the base station in DCI.

[0279] If UE #2 is configured as SL mode 2 (i.e., SL resource allocation mode 2), the CAPC may be configured by the base station via an RRC message (e.g., for the STCH of the SL-DRB). If the CAPC configured by the base station is not available, UE #2 may use the CAPC configured by UE #2.

[0280] If UE #2 cannot use the CAPC set by the base station and the CAPC set by UE #1, UE #2 can use the CAPC mapped to the PQI of the SL-DRB in Table 17 or the CAPC set by SL pre-configuration.

[0281] SCI Scheduling of SL data TB may indicate CAPC for PSFCH transmission carrying HARQ-ACK for TB or RLC ACK for SL data.

[0282] In step S1170, UE #1 can transmit a PSFCH carrying a HARQ-ACK using a Type 1 or Type 2 channel access procedure together with the CAPC indicated by the SCI received from UE #2.

[0283] As an example, if the SCI does not indicate a CAPC for HARQ-ACK transmission, UE #1 can transmit a PSFCH carrying the HARQ-ACK using a Type 1 or Type 2 channel access procedure with CAPC according to one of the following options:

[0284] Option 1: Fixed CAPC for SL HARQ-ACK

[0285] Option 2: CAPC set for the destination indicated by the received SCI and PSSCH

[0286] Option 3: CAPC configured for the resource pool, carrier or cell where the SL HARQ-ACK is transmitted

[0287] Option 4: CAPC associated with the selected sidelink grant for which the SL HARQ-ACK is sent

[0288] Option 5: Default CAPC

[0289] Option 6: CAPC configured in RRC message by UE#2 for the above mentioned purposes

[0290] Option 7: CAPC configured by the base station in an RRC message for the above mentioned purposes

[0291] UE #1 may perform LBT with the determined CAPC (S1180). In step S1185, UE #1 may transmit a PSCCH carrying an SCI and a SL MAC CE to UE #2 and / or UE #3. UE #2 and / or UE #3 may transmit a PSFCH including a NACK-only based SL HARQ-ACK to UE #1 (S1190).

[0292] UE #1 can transmit SCI and PSSCH using Type 1 or Type 2 channel access procedure with fixed CAPC for SL MAC CE.

[0293] Or, if the SL MAC CE (e.g., SL CSI reporting MAC CE) is triggered by the SCI transmitted by UE #2, the CAPC indicated by UE #2 (i.e., by the SCI) may be used for type 1 or type 2 channel access procedure.

[0294] If the SCI does not indicate CAPC, UE #1 can transmit the SCI and PSCCH using Type 1 or Type 2 channel access procedure with CAPC according to one of the following options:

[0295] Option 1: Fixed CAPC for SL HARQ-ACK

[0296] Option 2: CAPC set for the destination indicated by the received SCI and PSSCH

[0297] Option 3: CAPC configured for the resource pool, carrier or cell where the SL HARQ-ACK is transmitted

[0298] Option 4: CAPC associated with the selected sidelink grant for which the SL HARQ-ACK is sent

[0299] Option 5: Default CAPC

[0300] Option 6: CAPC configured in RRC message by UE#2 for the above mentioned purposes

[0301] Option 7: CAPC configured by the base station in an RRC message for the above mentioned purposes

[0302] At the above-mentioned stage, the MAC entity of UE #1 or UE #2 can perform a logical channel priority procedure for each SL resource (i.e., each SL grant scheduled by the SCI) and generate a MAC PDU (i.e., TB) for SL resource transmission in the manner described below.

[0303] Prioritization of logical channels in MAC

[0304] 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 unicast, groupcast and broadcast having at least one MAC CE and highest priority logical channel among the logical channels that satisfy both the following conditions and the MAC CE for the SCI and associated SL grant:

[0305] - SL data may be used for transmission; and

[0306] - SBj>0, if there exists a logical channel with SBj>0; and

[0307] - if the SL grant is of configured grant type 1, then 'sl-configuredGrantType1Allowed' (if configured) is set to 'true';

[0308] - "sl-AllowedCG-List" (if set) contains the configured grant indexes associated with SL grants;

[0309] - "sl-HARQ-FeedbackEnabled" is set as inactive if the PSFCH is not configured for the SL grant associated with the SCI;

[0310] - SL data or SL MAC CE may be mapped to a CAPC value (eg based on the PQI of the SL data or the SL logical channel of the SL data CAPC) that is less than or equal to the CAPC value indicated or configured for the SL grant.

[0311] The operation of mapping the SL data or SL MAC CE to a CAPC value less than or equal to the CAPC value indicated or configured for the SL grant may be performed if the CAPC is indicated by a DCI indicating the SL grant, if the CAPC is indicated by an SCI triggering the SL data or SL MAC CE, if the CAPC is configured by an RRC message for the SL grant or the SL grant of the SL, or if the CAPC is associated with the selected sidelink grant of the SL grant.

[0312] In the case where multiple destinations have the same highest priority and have logical channels that satisfy all the above conditions, or multiple destinations have the same priority as the MAC CE and / or the MAC CE and have logical channels that satisfy all the above conditions, the selection of a specific destination from among the above destinations may be determined by the terminal implementation.

[0313] The terminal can then select a logical channel that satisfies all of the following conditions from among the logical channels that belong to the selected destination:

[0314] - SL data may be used for transmission; and

[0315] - SBj>0, if there exists a logical channel with SBj>0; and

[0316] - if the SL grant is of configured grant type 1, then 'sl-configuredGrantType1Allowed' is set to 'true' (if configured);

[0317] - "sl-AllowedCG-List" (if set) contains the configured grant indexes associated with SL grants; and

[0318] 1> If PSFCH is configured for a sidelink grant associated with SCI:

[0319] 2> When "sl-HARQ-FeedbackEnabled" is set as active for the highest priority logical channel that satisfies the above condition, "sl-HARQ-FeedbackEnabled" is set as active; or

[0320] 2> When "sl-HARQ-FeedbackEnabled" is set as inactive for the highest priority logical channel that satisfies the above condition, "sl-HARQ-FeedbackEnabled" may be set as inactive.

[0321] 3>If not:

[0322] 4> "sl-HARQ-FeedbackEnabled" may be set as inactive.

[0323] - SL data or SL MAC CE may be mapped to a CAPC value (eg based on the PQI of the SL data or the SL logical channel of the SL data CAPC) that is less than or equal to the CAPC value indicated or configured for the SL grant.

[0324] The SL data or SL MAC CE is mapped to a CAPC value less than or equal to the CAPC value indicated or configured for the SL grant. This may be done if the CAPC is indicated by a DCI indicating the SL grant, if the CAPC is indicated by an SCI triggering the SL data or SL MAC CE, if the CAPC is configured by an RRC message for the SL grant or the SL grant of the SL, or if the CAPC is associated with the selected sidelink grant of the SL grant.

[0325] For transmission of a MAC PDU conveying 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 consistency information MAC CE, the HARQ feedback activation / deactivation indicator may be set to deactivation.

[0326] For each SCI and SL grant corresponding to a new transmission, the MAC entity may generate a MAC PDU containing SL data only on the selected logical channel for the HARQ entity. The terminal may transmit the MAC PDU (i.e., TB) using type 1 or type 2 channel access procedures with CAPC indicated or configured for the SL grant.

[0327] In the description of this disclosure, sidelink transmissions, grants and resources may be replaced with uplink transmissions, grants and resources.

[0328] According to the above-described embodiment, (when the terminal performs SL transmission in an unlicensed band), the terminal can generate transmission blocks from one or more logical channels or MAC CEs with logical channel prioritization for the SL resources using a channel access procedure together with the CAPC determined for the SL resources.

[0329] Apparatuses to which the present disclosure can be applied

[0330] FIG. 12 illustrates a block diagram of a wireless communication device according to an embodiment of the present disclosure.

[0331] Referring to FIG. 12, a first device 100 and a second device 200 can transmit and receive wireless signals via various wireless connection technologies (e.g., LTE, NR).

[0332] The first device 100 includes 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 be configured to control the memory 104 and / or the transceiver 106 to implement the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams disclosed in the present disclosure.

[0333] For example, the processor 102 may process the information in the memory 104 to generate a first information / signal and then transmit a wireless signal including the first information / signal from the transceiver 106. The processor 102 may also receive a wireless signal including a second information / signal from the transceiver 106 and then store in the memory 104 information resulting from signal processing of the second information / signal.

[0334] The memory 104 may be coupled 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 instructions for performing a part or all of the processes controlled by the processor 102 or for executing the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams disclosed in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to embody a wireless communication technology (e.g., LTE, NR). The transceiver 106 may be coupled to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be referred to as a Radio Frequency (RF) unit. In the present disclosure, the device may mean a communication modem / circuit / chip.

[0335] The second device 200 may include one or more processors 202, 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 be configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. For example, the processor 202 may process information in the memory 204 to generate a third information / signal, and then transmit a wireless signal including the third information / signal from the transceiver 206. The processor 202 may also receive a wireless signal including a fourth information / signal from the transceiver 206, and then store information obtained from signal processing of the fourth information / signal in the memory 204. The memory 204 may be coupled to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for performing some or all of the processes controlled by the processor 202 or executing the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams disclosed in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to embody a wireless communication technology (e.g., LTE, NR). The transceiver 206 may be coupled to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be referred to as an RF unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0336] The hardware elements of the devices 100, 200 are described in more detail below. One or more protocol layers may be embodied by one or more processors 102, 202, without being limited thereto. For example, one or more processors 102, 202 may embody 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 Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. The one or more processors 102, 202 can generate and provide signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information to one or more transceivers 106, 206 according to the functions, procedures, suggestions, and / or methods disclosed in this disclosure. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure.

[0337] The one or more processors 102, 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The one or more processors 102, 202 may be embodied in hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure may be embodied using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, etc. Firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be included in one or more processors 102, 202 or stored in one or more memories 104, 204 and executed by one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be embodied in firmware or software in the form of code, instructions and / or collections of instructions.

[0338] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories 104, 204 may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories 104, 204 may be located internal and / or external to the one or more processors 102, 202. Also, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 by various techniques, such as wired or wireless coupling.

[0339] The one or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as referred to in the methods and / or operational flow diagrams of the present disclosure, to one or more other devices. The one or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams of the present disclosure, from one or more other devices. For example, the one or more transceivers 106, 206 may be coupled to one or more processors 102, 202 and may transmit and receive wireless signals. For example, the one or more processors 102, 202 may control the one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, the one or more processors 102, 202 may control the 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 coupled to one or more antennas 108, 208, and the one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, radio signals / channels, etc., as described, functions, procedures, suggestions, methods, and / or operation flow diagrams disclosed in the present disclosure, via the one or more antennas 108, 208. In the present disclosure, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 may convert the received radio signals / channels, etc., from RF band signals to baseband signals for processing the received user data, control information, radio signals / channels, etc., using one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, radio signals / channels, etc., processed using one or more processors 102, 202, from baseband signals to RF band signals. To that end, one or more of the transceivers 106, 206 may include (analog) oscillators and / or filters.

[0340] The above-described embodiments are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered as optional unless otherwise expressly stated. Each component or feature may be implemented in a form not combined with other components or features. It is also possible to combine some components and / or features to configure the embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some configurations or features of one embodiment may be included in another embodiment, or may be replaced with corresponding configurations or features of another embodiment. It is clear that claims that do not have an explicit reference relationship in the claims may be combined to configure an embodiment, or may be included as a new claim by amendment after filing.

[0341] It is obvious to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted as limiting in any respect, but should be considered as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the attached claims, and any modifications within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0342] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause a device or computer to perform operations according to the methods of various embodiments, and non-transitory computer-readable media on which such software or instructions or the like can be stored and executed on a device or computer. Instructions available for programming a processing system to perform features described in the present disclosure may be stored on / in a storage medium or computer-readable storage medium, and computer program products including such storage media may be used to embody features described in the present disclosure. The storage medium may include high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, but is not limited thereto, and may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices that are located remotely from the processor. The memory or alternatively the non-volatile memory devices in the memory include non-transitory computer-readable storage media. The features described in this disclosure may be embodied in software and / or firmware stored on any one of a number of machine-readable media and capable of controlling the hardware of a processing system and allowing the processing system to interact with other mechanisms that utilize the results of embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0343] Here, the wireless communication technology implemented in the devices 100 and 200 of the present disclosure may include LTE, NR, and 6G as well as Narrowband Internet of Things (NB-IoT) for low power communication. At this time, for example, the NB-IoT technology may be an example of a Low Power Wide Area Network (LPWAN) technology, and may be implemented according to 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 devices 100 and 200 of the present disclosure may perform communication based on the LTE-M technology. At this time, as an example, the LTE-M technology may be an example of an LPWAN technology, and may be called various names such as eMTC (enhanced Machine Type Communication). For example, the LTE-M technology may be embodied by at least one of various standards such as 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, and is not limited to the above names. Additionally or alternatively, the wireless communication technology embodied in the devices 100 and 200 of the present disclosure may include at least one of ZigBee (registered trademark), Bluetooth (registered trademark), and Low Power Wide Area Network (LPWAN), which consider low power communication, and is not limited to the above names. As an example, the ZigBee technology may generate personal area networks (PANs) related to small / low power digital communication based on various standards such as IEEE 802.15.4, and may be called various names. [Industrial Applicability]

[0344] The method proposed in this disclosure has been described mainly as being applied to 3GPP LTE / LTE-A and 5G systems, but it can be applied to various wireless communication systems other than 3GPP LTE / LTE-A and 5G systems.

Claims

1. A method for a first terminal performing sidelink (SL) communication in a wireless communication system, the method comprising: selecting a destination based on a channel access priority class (CAPC) value corresponding to a particular selected SL grant; selecting at least one logical channel for the selected destination; configuring at least one transport block (TB) based on the at least one selected logical channel; and transmitting the at least one TB to at least one other terminal corresponding to the destination.

2. 2. The method of claim 1, wherein the CAPC value is received from a base station in downlink control information (DCI) including the specific selected SL grant based on the SL resource allocation mode 1 being configured for the first terminal.

3. The method of claim 1 , wherein the CAPC value is based on a logical channel corresponding to the particular selected SL grant, based on SL resource allocation mode 2 being configured for the first terminal.

4. The method of claim 1, wherein configuration information related to at least one SL resource pool is received from a base station, and the CAPC value corresponds to a specific SL resource pool among the at least one SL resource pool based on SL resource allocation mode 2 being configured for the first terminal.

5. 2. The method of claim 1, wherein the CAPC value is indicated by a SL medium access control (MAC) control element (CE) or sidelink control information (SCI) triggering SL data transmitted on the at least one logical channel.

6. The destination includes a specific service based on the SL communication being a broadcast communication; Based on the fact that the SL communication is a groupcast communication, the destination includes a specific terminal group; The method of claim 1 , wherein the destination comprises a target terminal based on the SL communication being a unicast communication.

7. The method of claim 1 , wherein information related to SL MAC CE or SL data transmitted on the at least one logical channel is mapped to a CAPC value corresponding to the at least one logical channel.

8. The method of claim 1 , wherein the at least one logical channel is selected based on a CAPC value determined for the particular selected SL grant.

9. The at least one TB is generated based on SL data corresponding to the selected at least one logical channel; The method of claim 1 , wherein the at least one TB is transmitted by using a channel access procedure based on a CAPC value corresponding to the selected SL grant.

10. A first terminal performing sidelink (SL) communication in a wireless communication system, the first terminal comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Selecting a destination based on a channel access priority class (CAPC) value corresponding to a particular selected SL grant; selecting at least one logical channel for the selected destination; configuring at least one transport block (TB) based on the at least one selected logical channel; A first terminal configured to transmit, via the one or more transceivers, the at least one TB to at least one other terminal corresponding to the destination.

11. A method for a second terminal performing sidelink (SL) communication in a wireless communication system, the method comprising: establishing an SL unicast or groupcast connection with a first terminal; receiving from the first terminal at least one TB generated based on at least one logical channel corresponding to a destination associated with a CAPC value corresponding to a particular selected SL grant; transmitting HARQ-ACK information for the at least one TB to the first terminal on a physical sidelink feedback channel (PSFCH).

12. A second terminal performing sidelink (SL) communication in a wireless communication system, the second terminal comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Establish an SL unicast or groupcast connection with the first terminal; receiving from the first terminal via the one or more transceivers at least one TB generated based on at least one logical channel corresponding to a destination associated with a CAPC value corresponding to a particular selected SL grant; A second terminal configured to transmit HARQ-ACK information for the at least one TB to the first terminal on a physical sidelink feedback channel (PSFCH) via the one or more transceivers.

13. 1. A processing device configured to control a first terminal for sidelink (SL) communication in a wireless communication system, the processing device comprising: one or more processors; one or more computer memories operatively coupled to the one or more processors and configured to store instructions that perform operations based on being executed by the one or more processors; The operation includes: selecting a destination based on a channel access priority class (CAPC) value corresponding to a particular selected SL grant; selecting at least one logical channel for the selected destination; configuring at least one transport block (TB) based on the selected at least one logical channel; and transmitting the at least one TB via the one or more transceivers to at least one other terminal corresponding to the destination.

14. one or more non-transitory computer-readable media storing one or more instructions, The one or more instructions are executed by one or more processors, providing an apparatus for sidelink communication in a wireless communication system, comprising: Selecting a destination based on a channel access priority class (CAPC) value corresponding to a particular selected SL grant; selecting at least one logical channel for the selected destination; configuring at least one transport block (TB) based on the at least one selected logical channel; and transmitting, via the one or more transceivers, the at least one TB to at least one other terminal corresponding to the destination.

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