Method and apparatus for requesting retransmission resources in NR V2X

Abstract

A method for a first device to perform wireless communication and an apparatus for supporting the method are provided. The method may include the following steps: receiving information related to a first sublink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station; sending a medium access control packet data unit (MAC PDU) to a second device by using the first SL resource, wherein the MAC PDU includes a packet related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and the MAC PDU does not include a packet related to a logical channel for which HARQ feedback is enabled; determining that the MAC PDU needs to be retransmitted; and sending NACK information to the base station by using the first PUCCH resource based on the absence of SL authorization available for retransmitting the MAC PDU.

Description

Technical Field

[0001] The present disclosure relates to wireless communication systems. Background Art

[0002] Side Link (SL) communication is a communication scheme in which a direct link is established between User Equipments (UEs) and the UEs exchange voice and data directly with each other without intervention of an evolved Node B (eNB). SL communication is being considered as a solution to eNB overhead caused by the rapid growth of data traffic.

[0003] V2X (Vehicle-to-Everything) refers to the communication technology used by vehicles to exchange information with other vehicles, pedestrians, and infrastructure-equipped objects. V2X can be categorized into four types: V2V (Vehicle-to-Vehicle), V2I (Vehicle-to-Infrastructure), V2N (Vehicle-to-Network), and V2P (Vehicle-to-Pedestrian). V2X communication can be provided via the PC5 interface and / or the Uu interface.

[0004] In addition, as more and more communication devices require larger communication capacity, there is a need for enhanced mobile broadband communication compared to traditional radio access technologies (RATs). Therefore, the design of communication systems that take into account UEs or services that are sensitive to reliability and latency has also been discussed, and the next generation of radio access technologies that take into account enhanced mobile broadband communication, massive MTC, and ultra-reliable low-latency communication (URLLC) can be referred to as new RATs (radio access technologies) or NRs (new radios).

[0005] Figure 1 This diagram describes NR-based V2X communication compared to V2X communication based on RATs used before NR. Figure 1 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0006] Regarding V2X communication, when discussing RATs used prior to NR, the focus is on solutions that provide safety services based on V2X messages such as BSM (Basic Safety Message), CAM (Cooperation Awareness Message), and DENM (Decentralized Environment Notification Message). V2X messages may include location information, dynamic information, attribute information, etc. For example, a UE may send a periodic CAM message type and / or an event-triggered DENM message type to another UE.

[0007] For example, a CAM can include dynamic vehicle status information such as direction and speed, static vehicle data such as size, and basic vehicle information such as exterior lighting status and route details. For example, a UE can broadcast a CAM, and the latency of the CAM can be less than 100ms. For example, a UE can generate a DENM and transmit it to another UE in unexpected situations such as vehicle breakdown or accidents. For example, all vehicles within the UE's transmission range can receive the CAM and / or DENM. In this case, the DENM can take precedence over the CAM.

[0008] Since then, various V2X scenarios have been proposed for NR regarding V2X communications, including vehicle platooning, advanced driving, extended sensors, and remote driving.

[0009] For example, based on a vehicle platoon, vehicles can be dynamically formed into groups to move together. For example, to perform platooning operations based on a vehicle platoon, vehicles in the group can receive periodic data from a lead vehicle. For example, vehicles in the group can use the periodic data to reduce or increase the spacing between vehicles.

[0010] For example, based on advanced driving, vehicles can be semi-autonomous or fully autonomous. For example, each vehicle can adjust its trajectory or maneuver based on data obtained from local sensors of nearby vehicles and / or nearby logical entities. In addition, for example, each vehicle can share driving intentions with nearby vehicles.

[0011] For example, based on the extended sensors, raw data, processed data, or real-time video data obtained through local sensors can be exchanged between vehicles, logical entities, pedestrian UEs, and / or V2X application servers. This allows the vehicle to recognize a further improved environment compared to the environment detected using its own sensors, for example.

[0012] For example, remote driving can enable a person or remote vehicle in a dangerous environment to operate or control a remote vehicle, using a remote driver or V2X application. For example, if the route is predictable (e.g., public transportation), cloud-based driving can be used to operate or control the remote vehicle. Furthermore, remote driving can be achieved by accessing a cloud-based backend service platform.

[0013] In addition, schemes for specifying service requirements for various V2X scenarios such as vehicle platooning, advanced driving, extended sensors, remote driving, etc. are discussed in NR-based V2X communication. Summary of the Invention

[0014] Technical Purpose

[0015] Furthermore, if the base station schedules / allocates SL resources to the TX UE using an SL grant, the TX UE can use the SL resources to transmit a HARQ-enabled MAC PDU or a HARQ-disabled MAC PDU to the RX UE. Furthermore, the TX UE can request SL resources from the base station for additional retransmissions. In this case, it is necessary to provide a method for the TX UE to efficiently request SL resources from the base station for additional retransmissions and a device supporting this method.

[0016] Technical Solution

[0017] In one embodiment, a method for performing wireless communication by a first device is provided. The method may include the following steps: receiving information related to a first sublink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station; sending a medium access control (MAC) packet data unit (PDU) to a second device by using the first SL resource, wherein the MAC PDU includes a packet related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and wherein the MAC PDU does not include a packet related to a logical channel for which HARQ feedback is enabled; determining that the MAC PDU needs to be retransmitted; and sending NACK information to the base station by using the first PUCCH resource based on the lack of SL authorization available for retransmitting the MAC PDU.

[0018] In one embodiment, a first device configured to perform wireless communication is provided. The first device may include: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute instructions to: receive information related to a first sublink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station; send a medium access control (MAC) packet data unit (PDU) to a second device by using the first SL resource, wherein the MAC PDU includes a packet related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and wherein the MAC PDU does not include a packet related to a logical channel for which HARQ feedback is enabled; determine that the MAC PDU needs to be retransmitted; and based on the absence of an SL grant available for retransmitting the MAC PDU, send NACK information to the base station by using the first PUCCH resource.

[0019] Effects of the present disclosure

[0020] The user equipment (UE) can efficiently perform SL communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This diagram describes NR-based V2X communication compared to V2X communication based on RATs used before NR.

[0022] Figure 2 The structure of the NR system according to an embodiment of the present disclosure is shown.

[0023] Figure 3 The functional division between NG-RAN and 5GC according to an embodiment of the present disclosure is shown.

[0024] Figure 4 A radio protocol architecture according to an embodiment of the present disclosure is shown.

[0025] Figure 5 The structure of the NR system according to an embodiment of the present disclosure is shown.

[0026] Figure 6 The structure of the time slot of the NR frame according to an embodiment of the present disclosure is shown.

[0027] Figure 7 An example of a BWP according to an embodiment of the present disclosure is shown.

[0028] Figure 8 A radio protocol architecture for SL communication according to an embodiment of the present disclosure is shown.

[0029] Figure 9 A UE performing V2X or SL communication according to an embodiment of the present disclosure is shown.

[0030] Figure 10 A process of performing V2X or SL communication by a UE based on a transmission mode according to an embodiment of the present disclosure is shown.

[0031] Figure 11 Three broadcast types are shown according to embodiments of the present disclosure.

[0032] Figure 12 A process in which a TX UE requests retransmission resources when a base station allocates SL resources and PUCCH resources to the TX UE according to an embodiment of the present disclosure is shown.

[0033] Figure 13 A process in which a TX UE requests retransmission resources when a base station allocates SL resources and PUCCH resources to the TX UE according to an embodiment of the present disclosure is shown.

[0034] Figure 14 A process in which a TX UE requests retransmission resources when a base station allocates SL resources and PUCCH resources to the TX UE according to an embodiment of the present disclosure is shown.

[0035] Figure 15 A method for performing wireless communication by a first device according to an embodiment of the present disclosure is shown.

[0036] Figure 16 A communication system 1 according to an embodiment of the present disclosure is shown.

[0037] Figure 17 A wireless device according to an embodiment of the present disclosure is shown.

[0038] Figure 18 A signal processing circuit for transmitting a signal according to an embodiment of the present disclosure is shown.

[0039] Figure 19 Another example of a wireless device according to an embodiment of the present disclosure is shown.

[0040] Figure 20 A handheld device according to an embodiment of the present disclosure is shown.

[0041] Figure 21 A vehicle or autonomous vehicle according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0042] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, in the present disclosure, "A or B" may be interpreted as "A and / or B". For example, in the present disclosure, "A, B or C" may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0043] As used in this disclosure, a slash ( / ) or a comma may mean "and / or". For example, "A / B" may mean "A and / or B". Thus, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

[0044] In the present disclosure, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, in the present disclosure, the expression “at least one of A or B” or “at least one of A and / or B” may be interpreted as “at least one of A and B”.

[0045] In addition, in the present disclosure, “at least one of A, B, and C” may mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.” In addition, “at least one of A, B, or C” or “at least one of A, B, and / or C” may mean “at least one of A, B, and C.”

[0046] In addition, the brackets used in the present disclosure may mean "for example". Specifically, when it is indicated as "control information (PDCCH)", this may mean that "PDCCH" is proposed as an example of "control information". In other words, the "control information" of the present disclosure is not limited to "PDCCH", and "PDDCH" may be proposed as an example of "control information". Specifically, when it is indicated as "control information (i.e., PDCCH)", this may also mean that "PDCCH" is proposed as an example of "control information".

[0047] The technical features described in each of the drawings in the present disclosure may be implemented separately or simultaneously.

[0048] The techniques described below can be used in various wireless communication systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. CDMA can be implemented using radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA-2000. TDMA can be implemented using radio technologies such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented using radio technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Evolved UTRA (E-UTRA), etc. IEEE 802.16m is an evolved version of IEEE 802.16e and provides backward compatibility for systems based on IEEE 802.16e. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) that uses E-UTRA. 3GPP LTE uses OFDMA in the downlink and SC-FDMA in the uplink. LTE-Advanced (LTE-A) is an evolution of LTE.

[0049] 5G NR is a successor technology to LTE-A, a new mobile communication system with high performance, low latency, and high availability. 5G NR can use all available spectrum resources, including low-frequency bands below 1 GHz, intermediate frequency bands from 1 GHz to 10 GHz, and high-frequency bands (millimeter waves) above 24 GHz.

[0050] For clarity of description, the following description will mainly focus on LTE-A or 5G NR. However, the technical features according to the embodiments of the present disclosure are not limited thereto.

[0051] Figure 2 The structure of the NR system according to an embodiment of the present disclosure is shown. Figure 2 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0052] Reference Figure 2 , the next generation radio access network (NG-RAN) may include a BS 20 that provides user plane and control plane protocol terminations for the UE 10. For example, the BS 20 may include a next generation Node B (gNB) and / or an evolved Node B (eNB). For example, the UE 10 may be fixed or mobile and may be referred to by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a mobile terminal (MT), a wireless device, etc. For example, the BS may be referred to as a fixed station that communicates with the UE 10 and may be referred to by other terms such as a base transceiver system (BTS), an access point (AP), etc.

[0053] Figure 2 The embodiment of the present invention illustrates a case where only gNBs are included. BSs 20 may be connected to each other via an Xn interface. BSs 20 may be connected to each other via a fifth-generation (5G) core network (5GC) and an NG interface. More specifically, BSs 20 may be connected to an access and mobility management function (AMF) 30 via an NG-C interface, and may be connected to a user plane function (UPF) 30 via an NG-U interface.

[0054] Figure 3 The functional division between NG-RAN and 5GC according to an embodiment of the present disclosure is shown.

[0055] Reference Figure 3 The gNB can provide functions such as inter-cell radio resource management (inter-cell RRM), radio bearer (RB) control, connection mobility control, radio admission control, measurement configuration and provisioning, dynamic resource allocation, etc. The AMF can provide functions such as non-access stratum (NAS) security and idle state mobility processing. The UPF can provide functions such as mobility anchoring and protocol data unit (PDU) processing. The session management function (SMF) can provide functions such as user equipment (UE) Internet Protocol (IP) address allocation and PDU session control.

[0056] The radio interface protocol layers between the UE and the network can be categorized as Layer 1 (L1), Layer 2 (L2), and Layer 3 (L3) based on the lower three layers of the Open Systems Interconnection (OSI) model, which is well known in communication systems. The physical (PHY) layer, belonging to Layer 1, provides information transmission services using physical channels, and the radio resource control (RRC) layer, located at Layer 3, controls radio resources between the UE and the network. To this end, the RRC layer exchanges RRC messages between the UE and the base station layer.

[0057] Figure 4 A radio protocol architecture according to an embodiment of the present disclosure is shown. Figure 4 The embodiments of can be combined with various embodiments of the present disclosure. Specifically, Figure 4 (a) shows the radio protocol architecture for the user plane, and Figure 4 (b) in FIG. 4 shows a radio protocol architecture for a control plane. The user plane corresponds to a protocol stack for user data transmission, and the control plane corresponds to a protocol stack for control signal transmission.

[0058] Reference Figure 4 The physical layer provides information transfer services to upper layers via physical channels. The physical layer is connected to the media access control (MAC) layer, which is the upper layer of the physical layer, via transport channels. Data is transferred between the MAC layer and the physical layer via transport channels. Transport channels are categorized based on how data is transmitted over the radio interface and the characteristics of the data being transmitted.

[0059] Data is transmitted between different PHY layers (ie, the PHY layer of the transmitter and the PHY layer of the receiver) through a physical channel. The physical channel may be modulated using an Orthogonal Frequency Division Multiplexing (OFDM) scheme and uses time and frequency as radio resources.

[0060] The MAC layer provides services to the Radio Link Control (RLC) layer, a higher layer above the MAC layer, via logical channels. The MAC layer maps multiple logical channels to multiple transport channels. The MAC layer also provides logical channel multiplexing by mapping multiple logical channels to a single transport channel. The MAC layer provides data transmission services via logical channels.

[0061] The RLC layer performs concatenation, segmentation, and reassembly of radio link control service data units (RLC SDUs). To ensure the different quality of service (QoS) required for radio bearers (RBs), the RLC layer provides three types of operation modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). AM RLC provides error correction through automatic repeat request (ARQ).

[0062] The Radio Resource Control (RRC) layer is defined only in the control plane. The RRC layer controls physical, transport, and logical channels related to the configuration, reconfiguration, and release of radio bearers. An RB is a logical path provided by Layer 1 (i.e., the PHY layer) and Layer 2 (i.e., the MAC layer, RLC layer, and PDCP layer) to transmit data between the UE and the network.

[0063] The functions of the Packet Data Convergence Protocol (PDCP) in the user plane include transmission of user data, header compression and encryption. The functions of the Packet Data Convergence Protocol (PDCP) in the control plane include transmission and encryption / integrity protection of control plane data.

[0064] The Service Data Adaptation Protocol (SDAP) layer is defined only in the user plane. The SDAP layer performs mapping between Quality of Service (QoS) flows and Data Radio Bearers (DRBs) and QoS Flow ID (QFI) marking in both DL and UL packets.

[0065] RB configuration refers to the process of specifying radio protocol layers and channel attributes to provide a specific service and determining corresponding detailed parameters and operation methods. RBs can then be classified into two types: signaling radio bearers (SRBs) and data radio bearers (DRBs). SRBs are used as a path for transmitting RRC messages in the control plane, and DRBs are used as a path for transmitting user data in the user plane.

[0066] When an RRC connection is established between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is in the RRC connected (RRC_CONNECTED) state, otherwise the UE may be in the RRC idle (RRC_IDLE) state. In the case of NR, an RRC inactive (RRC_INACTIVE) state is additionally defined, and the UE in the RRC_INACTIVE state may maintain its connection with the core network while releasing its connection with the BS.

[0067] The downlink transport channels for sending (or transmitting) data from the network to the UE include the broadcast channel (BCH) for sending system information and the downlink shared channel (SCH) for sending other user traffic or control messages. Traffic or control messages for downlink multicast or broadcast services can be sent via the downlink SCH or can be sent via a separate downlink multicast channel (MCH). In addition, the uplink transport channels for sending (or transmitting) data from the UE to the network include the random access channel (RACH) for sending initial control messages and the uplink shared channel (SCH) for sending other user traffic or control messages.

[0068] Examples of logical channels belonging to a higher layer of a transport channel and mapped to a transport channel may include a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), a multicast traffic channel (MTCH), etc.

[0069] A physical channel is configured from multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. A subframe is configured from multiple OFDM symbols in the time domain. A resource block is configured from multiple subcarriers and multiple OFDM symbols in a resource allocation unit. In addition, each subframe can use specific subcarriers of specific OFDM symbols (e.g., the first OFDM symbol) of the corresponding subframe of the physical downlink control channel (PDCCH), i.e., the L1 / L2 control channel. The transmission time interval (TTI) refers to the unit time for subframe transmission.

[0070] Figure 5 The structure of the NR system according to an embodiment of the present disclosure is shown. Figure 5 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0071] Reference Figure 5 In NR, a radio frame can be used to perform uplink and downlink transmissions. The length of a radio frame is 10ms and can be defined as consisting of two half frames (HF). A half frame can include five 1ms subframes (SF). A subframe (SF) can be divided into one or more time slots, and the number of time slots within a subframe can be determined according to the subcarrier spacing (SCS). Each time slot can include 12 or 14 OFDM (A) symbols depending on the cyclic prefix (CP).

[0072] When using a normal CP, each time slot can include 14 symbols. When using an extended CP, each time slot can include 12 symbols. Herein, a symbol may include an OFDM symbol (or a CP-OFDM symbol) and a single carrier-FDMA (SC-FDMA) symbol (or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol).

[0073] Table 1 below shows the number of time slots (N) per symbol according to the SCS setting (μ) when a normal CP is used. slot symb ), the number of time slots per frame (N frame,μ slot ) and the number of time slots per subframe (N subframe,μ slot ).

[0074] [Table 1]

[0075] <![CDATA[SCS(15*2 μ )]]> <![CDATA[N slot symb ]]> <![CDATA[N frame,μ slot ]]> <![CDATA[N subframe,μ slot ]]> 15KHz (μ=0) 14 10 1 30KHz (μ=1) 14 20 2 60KHz (μ=2) 14 40 4 120KHz (μ=3) 14 80 8 240KHz (μ=4) 14 160 16

[0076] Table 2 shows an example of the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to the SCS in the case of using the extended CP.

[0077] [Table 2]

[0078] <![CDATA[SCS(15*2 μ )]]> <![CDATA[N slot symb ]]> <![CDATA[N frame,μ slot ]]> <![CDATA[N subframe,μ slot ]]> 60KHz (μ=2) 12 40 4

[0079] In the NR system, OFDM(A) parameter sets (e.g., SCS, CP length, etc.) may be configured differently between multiple cells integrated into one UE. Therefore, the (absolute time) duration (or interval) of a time resource (e.g., subframe, time slot, or TTI) (collectively referred to as a time unit (TU) for simplicity) consisting of the same number of symbols may be configured differently in the integrated cells.

[0080] In NR, multiple parameter sets or SCSs can be supported to support various 5G services. For example, with an SCS of 15kHz, a wide range of traditional cellular frequency bands can be supported, and with an SCS of 30kHz / 60kHz, dense urban areas, lower latency, and wider carrier bandwidths can be supported. With an SCS of 60kHz or higher, bandwidths greater than 24.25GHz can be used to overcome phase noise.

[0081] The NR frequency band can be defined as two different types of frequency ranges. The two different types of frequency ranges may be FR1 and FR2. The values ​​of the frequency ranges may be changed (or varied), for example, the two different types of frequency ranges may be as shown in Table 3 below. Among the frequency ranges used in the NR system, FR1 may mean "a range below 6 GHz", and FR2 may mean "a range above 6 GHz", and may also be referred to as millimeter wave (mmW).

[0082] [Table 3]

[0083] Frequency range specification Corresponding frequency range Subcarrier spacing (SCS) FR1 450MHz-6000MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0084] As described above, the value of the frequency range in the NR system can be changed (or varied). For example, as shown in Table 4 below, FR1 may include a bandwidth in the range of 410 MHz to 7125 MHz. More specifically, FR1 may include frequency bands of 6 GHz (or 5850, 5900, 5925 MHz, etc.) and higher. For example, the frequency bands of 6 GHz (or 5850, 5900, 5925 MHz, etc.) and higher included in FR1 may include unlicensed bands. The unlicensed bands may be used for various purposes, for example, the unlicensed bands are used for vehicle-specific communications (e.g., autonomous driving).

[0085] [Table 4]

[0086] Frequency range specification Corresponding frequency range Subcarrier spacing (SCS) FR1 410MHz-7125MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0087] Figure 6 The structure of the time slot of the NR frame according to an embodiment of the present disclosure is shown.

[0088] Reference Figure 6 A slot includes multiple symbols in the time domain. For example, in the case of normal CP, one slot may include 14 symbols. For example, in the case of extended CP, one slot may include 12 symbols. Alternatively, in the case of normal CP, one slot may include 7 symbols. However, in the case of extended CP, one slot may include 6 symbols.

[0089] A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) can be defined as multiple consecutive subcarriers in the frequency domain (e.g., 12 subcarriers). A bandwidth part (BWP) can be defined as multiple consecutive (physical) resource blocks ((P)RBs) in the frequency domain, and a BWP can correspond to a parameter set (e.g., SCS, CP length, etc.). A carrier can include up to N BWPs (e.g., 5 BWPs). Data communication can be performed via activated BWPs. Each element can be referred to as a resource element (RE) in a resource grid, and a complex symbol can be mapped to each element.

[0090] In addition, the radio interface between a UE and another UE or between a UE and a network may include an L1 layer, an L2 layer, and an L3 layer. In various embodiments of the present disclosure, the L1 layer may refer to a physical layer. In addition, for example, the L2 layer may refer to at least one of a MAC layer, an RLC layer, a PDCP layer, and an SDAP layer. In addition, for example, the L3 layer may refer to an RRC layer.

[0091] Hereinafter, the bandwidth part (BWP) and the carrier will be described in detail.

[0092] A BWP may be a contiguous set of physical resource blocks (PRBs) within a given parameter set. A PRB may be selected from a contiguous set of common resource blocks (CRBs) for a given parameter set on a given carrier.

[0093] When bandwidth adaptation (BA) is used, the reception bandwidth and transmission bandwidth of the user equipment (UE) do not need to be as wide (or large) as the bandwidth of the cell, and the reception bandwidth and transmission bandwidth of the UE can be controlled (or adjusted). For example, the UE can receive information / configuration for bandwidth control (or adjustment) from the network / base station. In this case, bandwidth control (or adjustment) can be performed based on the received information / configuration. For example, bandwidth control (or adjustment) can include reducing / expanding the bandwidth, changing the position of the bandwidth, or changing the subcarrier spacing of the bandwidth.

[0094] For example, the bandwidth can be reduced during periods of low activity to save power. For example, the bandwidth can be relocated (or moved) from the frequency domain. For example, the bandwidth can be relocated (or moved) from the frequency domain to enhance scheduling flexibility. For example, the subcarrier spacing of the bandwidth can be changed. For example, the subcarrier spacing of the bandwidth can be changed to authorize different services. A subset of the total cell bandwidth of a cell can be referred to as a bandwidth part (BWP). BA can be performed when the base station / network configures a BWP for the UE and when the base station / network notifies the UE of the currently active BWP among the BWPs.

[0095] For example, the BWP may be one of an activated BWP, an initial BWP, and / or a default BWP. For example, the UE cannot monitor the downlink radio link quality in DL BWPs other than the activated DL BWP within the primary cell (PCell). For example, the UE cannot receive PDCCH, PDSCH, or CSI-RS (except for RRM) from outside the activated DL BWP. For example, the UE cannot trigger channel state information (CSI) reporting for an inactivated DL BWP. For example, the UE cannot send PUCCH or PUSCH from outside an inactivated DL BWP. For example, in the downlink, the initial BWP may be given as a set of contiguous RBs for the RMSI CORESET (configured by the PBCH). For example, in the uplink, the initial BWP may be given by the SIB for the random access procedure. For example, the default BWP may be configured by higher layers. For example, the initial value of the default BWP may be the initial DL BWP. To save energy, if the UE is unable to detect DCI within a predetermined period of time, the UE may switch the UE's active BWP to the default BWP.

[0096] In addition, a BWP can be defined for SL. The same SL BWP can be used for transmission and reception. For example, a transmitting UE can send a SL channel or SL signal within a specific BWP, and a receiving UE can receive a SL channel or SL signal within the same specific BWP. In a licensed carrier, the SL BWP can be defined separately from the Uu BWP, and the SL BWP can have configuration signaling separate from the Uu BWP. For example, the UE can receive a configuration for the SL BWP from the base station / network. The SL BWP can be configured (in advance) for NR V2X UEs and RRC_IDLE UEs out of coverage. For UEs operating in RRC_CONNECTED mode, at least one SL BWP can be activated within the carrier.

[0097] Figure 7 An example of a BWP according to an embodiment of the present disclosure is shown. Figure 7 The embodiments of can be combined with various embodiments of the present disclosure. Figure 7 In an embodiment, the number of BWPs is 3.

[0098] Reference Figure 7 , Common Resource Blocks (CRBs) may be carrier resource blocks numbered from one end of the carrier frequency band to the other. Additionally, PRBs may be resource blocks numbered within each BWP. Point A may indicate a common reference point for the resource block grid.

[0099] It can be obtained by point A, the offset relative to point A (N start BWP ) and bandwidth (N size BWP ) to configure the BWP. For example, point A can be an external reference point of the PRBs of a carrier, and subcarrier 0 of all parameter sets (e.g., all parameter sets supported by the network on the corresponding carrier) is aligned in point A. For example, the offset can be the PRB distance between the lowest subcarrier in a given parameter set and point A. For example, the bandwidth can be the number of PRBs in a given parameter set.

[0100] Hereinafter, V2X or SL communication will be described.

[0101] Figure 8 A radio protocol architecture for SL communication according to an embodiment of the present disclosure is shown. Figure 8 The embodiments of can be combined with various embodiments of the present disclosure. More specifically, Figure 8 (a) in FIG. 1 shows the user plane protocol stack, and Figure 8 (b) in FIG. 5 shows the control plane protocol stack.

[0102] Next, the sub-link synchronization signal (SLSS) and the synchronization information will be described in detail.

[0103] The SLSS may include a primary sublink synchronization signal (PSSS) and a secondary sublink synchronization signal (SSSS) as SL specific sequences. The PSSS may be referred to as a secondary link primary synchronization signal (S-PSS), and the SSSS may be referred to as a secondary link secondary synchronization signal (S-SSS). For example, an M sequence of length 127 may be used for the S-PSS, and a Gold sequence of length 127 may be used for the S-SSS. For example, the UE may use the S-PSS for initial signal detection and synchronization acquisition. For example, the UE may use the S-PSS and the S-SSS for acquiring detailed synchronization and for detecting the synchronization signal ID.

[0104] The physical sidelink broadcast channel (PSBCH) can be a (broadcast) channel for transmitting default (system) information, which must be known by the UE before SL signal transmission / reception. For example, the default information can be information related to SLSS, duplex mode (DM), time division duplex (TDD) uplink / downlink (UL / DL) configuration, information related to resource pool, type of application related to SLSS, subframe offset, broadcast information, etc. For example, in order to evaluate PSBCH performance, in NR V2X, the payload size of PSBCH can be 56 bits, including a 24-bit CRC.

[0105] S-PSS, S-SSS and PSBCH can be included in a block format that supports periodic transmission (e.g., SL synchronization signal (SS) / PSBCH block, hereinafter, sublink synchronization signal block (S-SSB)). The S-SSB can have the same parameter set (i.e., SCS and CP length) as the physical sublink control channel (PSCCH) / physical sublink shared channel (PSSCH) in the carrier, and the transmission bandwidth can exist within the (pre-) configured sublink (SL) BWP. For example, the S-SSB can have a bandwidth of 11 resource blocks (SBs). For example, the PSBCH can exist across 11 RBs. In addition, the frequency position of the S-SSB can be (pre-) configured. Therefore, the UE does not have to perform hypothesis detection at the frequency to discover the S-SSB in the carrier.

[0106] Figure 9 A UE performing V2X or SL communication according to an embodiment of the present disclosure is shown. Figure 9 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0107] Reference Figure 9In V2X or SL communication, the term "UE" generally refers to a user's UE. However, if a network device such as a base station (BS) transmits and receives signals according to a communication scheme between UEs, the BS may also be considered a type of UE. For example, UE 1 may be first wireless device 100, and UE 2 may be second wireless device 200.

[0108] For example, UE 1 can select a resource unit corresponding to a specific resource from a resource pool representing a set of resources. Furthermore, UE 1 can transmit an SL signal using the resource unit. For example, a resource pool in which UE 1 can transmit a signal can be configured for UE 2, which is a receiving UE, and UE 1's signal can be detected in the resource pool.

[0109] Here, if UE 1 is within the connection range of the BS, the BS can inform UE 1 of the resource pool. Otherwise, if UE 1 is out of the connection range of the BS, another UE can inform UE 1 of the resource pool, or UE 1 can use a pre-configured resource pool.

[0110] Generally, a resource pool may be configured in units of multiple resources, and each UE may select one or more units of resources to use in its SL signaling.

[0111] Hereinafter, resource allocation in SL will be described.

[0112] Figure 10 A process of performing V2X or SL communication by a UE based on a transmission mode according to an embodiment of the present disclosure is shown. Figure 10 The embodiments of the present disclosure may be combined with the various embodiments of the present disclosure. In the various embodiments of the present disclosure, the transmission mode may be referred to as a mode or a resource allocation mode. Hereinafter, for ease of explanation, in LTE, the transmission mode may be referred to as the LTE transmission mode. In NR, the transmission mode may be referred to as the NR resource allocation mode.

[0113] For example, Figure 10 (a) in FIG. 1 shows UE operations related to LTE transmission mode 1 or LTE transmission mode 3. Alternatively, for example, Figure 10 (a) in FIG. 4 shows UE operations related to NR resource allocation mode 1. For example, LTE transmission mode 1 can be applied to conventional SL communication, and LTE transmission mode 3 can be applied to V2X communication.

[0114] For example, Figure 10 (b) in FIG. 4 shows UE operations related to LTE transmission mode 2 or LTE transmission mode 4. Alternatively, for example, Figure 10 (b) in FIG. 4 shows UE operations related to NR resource allocation mode 2.

[0115] Reference Figure 10 In (a), in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, the BS may schedule SL resources to be used by the UE for SL transmission. For example, the BS may perform resource scheduling for UE 1 via the PDCCH (more specifically, downlink control information (DCI)), and UE 1 may perform V2X or SL communication with UE 2 according to the resource scheduling. For example, UE 1 may transmit sidelink control information (SCI) to UE 2 via the physical sidelink control channel (PSCCH), and thereafter transmit data based on the SCI to UE 2 via the physical sidelink shared channel (PSSCH).

[0116] Reference Figure 10 (b) in LTE transmission mode 2, LTE transmission mode 4 or NR resource allocation mode 2, the UE can determine the SL transmission resources within the SL resources configured by the BS / network or the pre-configured SL resources. For example, the configured SL resources or the pre-configured SL resources can be a resource pool. For example, the UE can autonomously select or schedule resources for SL transmission. For example, the UE can perform SL communication by autonomously selecting resources in the configured resource pool. For example, the UE can autonomously select resources within the selection window by performing sensing and resource (re)selection processes. For example, sensing can be performed in units of subchannels. In addition, UE 1, which has autonomously selected resources in the resource pool, can send SCI to UE 2 via PSCCH, and thereafter send data based on the SCI to UE 2 via PSSCH.

[0117] Figure 11 Three broadcast types are shown in accordance with embodiments of the present disclosure. Figure 11 The embodiments of can be combined with various embodiments of the present disclosure. Specifically, Figure 11 (a) shows a broadcast type SL communication, Figure 11 (b) in FIG. 4 shows unicast type SL communication, and Figure 11 (c) in FIG. 5 shows multicast SL communication. In the case of unicast SL communication, the UE can perform one-to-one communication with another UE. In the case of multicast SL transmission, the UE can perform SL communication with one or more UEs in the group to which the UE belongs. In various embodiments of the present disclosure, SL groupcast communication can be replaced by SL multicast communication, SL one-to-many communication, etc.

[0118] Hereinafter, a hybrid automatic repeat request (HARQ) process will be described.

[0119] An error compensation scheme is used to ensure the reliability of communication. Examples of error compensation schemes may include a forward error correction (FEC) scheme and an automatic repeat request (ARQ) scheme. In the FEC scheme, errors in the receiving end can be corrected by appending an additional error correction code to the information bits. The FEC scheme has the advantages of small time delay and no additional information exchange between the transmitting and receiving ends, but also has the disadvantage of reduced system efficiency in a good channel environment. The ARQ scheme has the advantage of improving transmission reliability, but also has the disadvantage of deteriorating system efficiency and causing time delay in a poor channel environment.

[0120] A hybrid automatic repeat request (HARQ) scheme is a combination of an FEC scheme and an ARQ scheme. In the HARQ scheme, whether unrecoverable errors are included in data received by a physical layer is determined, and retransmission is requested when an error is detected, thereby improving performance.

[0121] In the case of SL unicast and multicast, HARQ feedback and HARQ combining in the physical layer can be supported. For example, when the receiving UE operates in resource allocation mode 1 or 2, the receiving UE can receive PSSCH from the transmitting UE, and the receiving UE can send HARQ feedback for PSSCH to the transmitting UE using the sidelink feedback control information (SFCI) format via the physical sidelink feedback channel (PSFCH).

[0122] For example, SL HARQ feedback can be enabled for unicast. In this case, in non-code block group (non-CBG) operation, if the receiving UE decodes the PSCCH whose target is the receiving UE, and if the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE can generate a HARQ-ACK. In addition, the receiving UE can send a HARQ-ACK to the transmitting UE. Otherwise, if the receiving UE cannot successfully decode the transport block after decoding the PSCCH whose target is the receiving UE, the receiving UE can generate a HARQ-NACK. In addition, the receiving UE can send a HARQ-NACK to the transmitting UE.

[0123] For example, SL HARQ feedback may be enabled for multicast.For example, in non-CBG operation, two HARQ feedback options may be supported for multicast.

[0124] (1) Multicast Option 1: After a receiving UE decodes a PSCCH targeted at the receiving UE, if the receiving UE fails to decode the transport block associated with the PSCCH, the receiving UE may send a HARQ-NACK to the transmitting UE via the PSFCH. Otherwise, if the receiving UE decodes the PSCCH targeted at the receiving UE and if the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE may not send a HARQ-ACK to the transmitting UE.

[0125] (2) Multicast Option 2: After a receiving UE decodes a PSCCH targeted for the receiving UE, if the receiving UE fails to decode the transport block associated with the PSCCH, the receiving UE may send a HARQ-NACK to the transmitting UE via the PSFCH. Alternatively, if the receiving UE decodes a PSCCH targeted for the receiving UE and successfully decodes the transport block associated with the PSCCH, the receiving UE may send a HARQ-ACK to the transmitting UE via the PSFCH.

[0126] For example, if multicast option 1 is used for SL HARQ feedback, all UEs performing multicast communication can share PSFCH resources. For example, UEs belonging to the same group can send HARQ feedback by using the same PSFCH resources.

[0127] For example, if multicast option 2 is used for SL HARQ feedback, each UE performing multicast communication may use a different PSFCH resource for HARQ feedback transmission. For example, UEs belonging to the same group may send HARQ feedback by using different PSFCH resources.

[0128] For example, when SL HARQ feedback is enabled for multicast, the receiving UE may determine whether to send HARQ feedback to the transmitting UE based on transmit-receive (TX-RX) distance and / or RSRP.

[0129] For example, in multicast option 1, in the case of HARQ feedback based on TX-RX distance, if the TX-RX distance is less than or equal to the communication range requirement, the receiving UE may send HARQ feedback for the PSSCH to the transmitting UE. Otherwise, if the TX-RX distance is greater than the communication range requirement, the receiving UE may not send HARQ feedback for the PSSCH to the transmitting UE. For example, the transmitting UE may inform the receiving UE of the location of the transmitting UE via the SCI associated with the PSSCH. For example, the SCI associated with the PSSCH may be a second SCI. For example, the receiving UE may estimate or obtain the TX-RX distance based on the location of the receiving UE and the location of the transmitting UE. For example, the receiving UE may decode the SCI associated with the PSSCH and therefore may know the communication range requirement for the PSSCH.

[0130] For example, in the case of resource allocation mode 1, the time (offset) between PSFCH and PSSCH can be configured or pre-configured. In the case of unicast and multicast, if retransmission is necessary on SL, it can be indicated to the BS by the UE within the coverage using PUCCH. The sending UE can send an indication to the serving BS of the sending UE in the form of a scheduling request (SR) / buffer status report (BSR) rather than a HARQ ACK / NACK. In addition, even if the BS does not receive the indication, the BS can schedule SL retransmission resources for the UE. For example, in the case of resource allocation mode 2, the time (offset) between PSFCH and PSSCH can be configured or pre-configured.

[0131] For example, from the perspective of UE transmission in a carrier, TDM between PSCCH / PSSCH and PSFCH can allow PSFCH formats for SL in a time slot. For example, a sequence-based PSFCH format with a single symbol can be supported. In this article, the single symbol may not be the AGC duration. For example, the sequence-based PSFCH format can be applied to unicast and multicast.

[0132] For example, in a time slot associated with a resource pool, the PSFCH resource may be periodically configured to have a duration of N time slots, or may be pre-configured. For example, N may be configured to be one or more values ​​greater than or equal to 1. For example, N may be 1, 2, or 4. For example, HARQ feedback for transmissions in a specific resource pool may be sent via the PSFCH only on that specific resource pool.

[0133] For example, if a transmitting UE transmits a PSSCH to a receiving UE across time slot #X to time slot #N, the receiving UE may transmit HARQ feedback for the PSSCH to the transmitting UE in time slot #(N+A). For example, time slot #(N+A) may include PSFCH resources. Herein, for example, A may be a minimum integer greater than or equal to K. For example, K may be the number of logical time slots. In this case, K may be the number of time slots in a resource pool. Alternatively, for example, K may be the number of physical time slots. In this case, K may be the number of time slots inside or outside the resource pool.

[0134] For example, if a receiving UE sends HARQ feedback on a PSFCH resource in response to a PSSCH sent by a transmitting UE to a receiving UE, the receiving UE may determine the frequency domain and / or code domain of the PSFCH resource based on an implicit mechanism in a configured resource pool. For example, the receiving UE may determine the frequency domain and / or code domain of the PSFCH resource based on at least one of a slot index associated with the PSCCH / PSSCH / PSFCH, a subchannel associated with the PSCCH / PSSCH, or an identifier for each receiving UE in a group for HARQ feedback based on multicast option 2. Additionally / alternatively, for example, the receiving UE may determine the frequency domain and / or code domain of the PSFCH resource based on at least one of SL RSRP, SINR, L1 source ID, and / or location information.

[0135] For example, if HARQ feedback transmission via the UE's PSFCH overlaps with HARQ feedback reception via the PSFCH, the UE may select either HARQ feedback transmission via the PSFCH or HARQ feedback reception via the PSFCH based on a priority rule. For example, the priority rule may be based on at least a priority indication of the related PSCCH / PSSCH.

[0136] For example, if HARQ feedback transmissions to multiple UEs via PSFCH overlap, the UE may select a specific HARQ feedback transmission based on a priority rule. For example, the priority rule may be based on at least a priority indication of the related PSCCH / PSSCH.

[0137] In addition, in the present disclosure, for example, a transmitting UE (TX UE) may be a UE that transmits data to a (target) receiving UE (RX UE). For example, the TX UE may be a UE that performs PSCCH transmission and / or PSSCH transmission. Additionally / alternatively, for example, the TX UE may be a UE that transmits an SL CSI-RS and / or an SL CSI report request indicator to a (target) RX UE. Additionally / alternatively, for example, the TX UE may be a UE that transmits a (control) channel (e.g., PSCCH, PSSCH, etc.) and / or a reference signal (e.g., DM-RS, CSI-RS, etc.) on the (control) channel for SL RLM operation and / or SL RLF operation of the (target) RX UE.

[0138] In addition, in the present disclosure, for example, a receiving UE (RX UE) may be a UE that sends SL HARQ feedback to a transmitting UE (TX UE) based on whether decoding of data received from the TX UE is successful and / or whether detection / decoding of a PSCCH (related to PSSCH scheduling) sent by the TX UE is successful. Additionally / alternatively, for example, the RX UE may be a UE that performs SL CSI transmission to the TX UE based on an SL CSI-RS and / or an SL CSI report request indicator received from the TX UE. Additionally / alternatively, for example, the RX UE may be a UE that sends an SL (L1) reference signal received power (RSRP) measurement value measured based on a (predefined) reference signal and / or an SL (L1) reference signal received power (RSRP) report request indicator received from the TX UE to the TX UE. Additionally / alternatively, for example, the RX UE may be a UE that sends data of the RX UE to the TX UE. Additionally / alternatively, for example, the RX UE may be a UE that performs SLRLM operation and / or SL RLF operation based on a (pre-configured) (control) channel and / or a reference signal on the (control) channel received from the TX UE.

[0139] In addition, in the present disclosure, for example, when the RX UE sends SL HARQ feedback information for the PSSCH and / or PSCCH received from the TX UE, the following options or some of the following options may be considered. Herein, for example, the following options or some of the following options may be restrictedly applied only when the RX UE successfully decodes / detects the PSCCH that schedules the PSSCH.

[0140] (1) Multicast HARQ feedback option 1: NACK information can be sent to the TX UE only if the RX UE fails to decode / receive the PSSCH received from the TX UE.

[0141] (2) Multicast HARQ feedback option 2: If the RX UE successfully decodes / receives the PSSCH received from the TX UE, ACK information may be sent to the TX UE, and if the RX UE fails to decode / receive the PSSCH, NACK information may be sent to the TX UE.

[0142] In addition, in the present disclosure, for example, the TX UE may transmit the following information or some of the following information to the RX UE through the SCI. Herein, for example, the TX UE may transmit some or all of the following information to the RX UE through the first SCI and / or the second SCI.

[0143] -PSSCH (and / or PSCCH) related resource allocation information (e.g., location / number of time / frequency resources, resource reservation information (e.g., period))

[0144] -SL CSI report request indicator or SL (L1) reference signal received power (RSRP) (and / or SL (L1) reference signal received quality (RSRQ) and / or SL (L1) reference signal strength indicator (RSSI)) report request indicator

[0145] -SLCSI transmission indicator (on PSSCH) (or SL(L1) RSRP (and / or SL(L1) RSRQ and / or SL(L1) RSSI) information transmission indicator)

[0146] - Modulation and Coding Scheme (MCS) information

[0147] -TX power information

[0148] - L1 destination ID information and / or L1 source ID information

[0149] -SL HARQ process ID information

[0150] -New Data Indicator (NDI) information

[0151] - Redundancy Version (RV) information

[0152] -QoS information (for example, priority information) (related to the transmission service / packet)

[0153] - Information on the number of antenna ports used for (transmitting) SL CSI-RS or SL CSI-RS transmission indicator

[0154] - Target RX UE location (or distance range) information or TX UE location information (for which SL HARQ feedback is requested)

[0155] Reference signal (e.g., DM-RS, etc.) information related to decoding (and / or channel estimation) of data transmitted via the PSSCH. For example, information related to the (time-frequency) mapping pattern of the DM-RS, rank information, antenna port index information, information about the number of antenna ports, etc.

[0156] In addition, in the present disclosure, for example, since the TX UE can transmit the SCI, the first SCI, and / or the second SCI to the RX UE via the PSCCH, the PSCCH can be replaced / replaced with the SCI and / or the first SCI and / or the second SCI. Additionally / alternatively, the SCI can be replaced / replaced with the PSCCH and / or the first SCI and / or the second SCI. Additionally / alternatively, for example, since the TX UE can transmit the second SCI to the RX UE via the PSSCH, the PSSCH can be replaced / replaced with the second SCI.

[0157] In addition, in the present disclosure, for example, if the SCI configuration field is divided into two groups considering the (relatively) high SCI payload size, the first SCI including the first SCI configuration field group may be referred to as the first SCI, and the second SCI including the second SCI configuration field group may be referred to as the second SCI. In addition, for example, the first SCI may be transmitted to the receiving UE via the PSCCH. In addition, for example, the second SCI may be transmitted to the receiving UE via a (separate) PSCCH, or may be piggybacked on the PSSCH and transmitted together with the data.

[0158] In addition, in the present disclosure, for example, the term "configured / configured" or the term "defined / defined" may refer to (pre-) configuration from a base station or network (for each resource pool) (through predefined signaling (e.g., SIB, MAC, RRC, etc.)).

[0159] Furthermore, in the present disclosure, for example, a packet or a service may be changed / replaced by a transport block (TB) or a medium access control (MAC) packet data unit (PDU) based on a transmission layer.

[0160] In addition, in the present disclosure, for example, the operation of the sending UE reserving / selecting / determining retransmission resources may include: the operation of the sending UE reserving / selecting / determining potential retransmission resources whose actual use will be determined based on the SL HARQ feedback information received from the receiving UE.

[0161] In addition, in the present disclosure, SL MODE 1 may refer to a resource allocation method or a communication method in which a base station directly schedules SL transmission resources for a TX UE through predefined signaling (e.g., DCI or RRC message). For example, SL MODE 2 may refer to a resource allocation method or a communication method in which a UE independently selects SL transmission resources from a resource pool pre-configured or configured from a base station or a network. For example, a UE that performs SL communication based on SL MODE 1 may be referred to as a MODE 1UE or a MODE 1TXUE, and a UE that performs SL communication based on SL MODE 2 may be referred to as a MODE 2UE or a MODE 2TX UE.

[0162] In addition, in the present disclosure, for example, a dynamic grant (DG) may be replaced / replaced by a configuration grant (CG) and / or a semi-persistent scheduling (SPS) grant, and vice versa. For example, a DG may be replaced / replaced by a combination of a CG and an SPS grant, and vice versa. In the present disclosure, a CG may include at least one of a configuration grant (CG) type 1 and / or a configuration grant (CG) type 2. For example, in CG type 1, the grant may be provided by RRC signaling and may be stored as a configuration grant. For example, in CG type 2, the grant may be provided by PDCCH and may be stored or deleted as a configuration grant based on L1 signaling indicating the enabling or disabling of the grant.

[0163] Furthermore, in the present disclosure, a channel may be replaced / replaced by a signal, and vice versa. For example, the transmission / reception of a channel may include the transmission / reception of a signal. For example, the transmission / reception of a signal may include the transmission / reception of a channel.

[0164] Furthermore, in the present disclosure, a broadcast may be replaced by at least one of unicast, multicast, and / or broadcast, and vice versa. For example, a broadcast type may be replaced by at least one of unicast, multicast, and / or broadcast, and vice versa. For example, a broadcast or broadcast type may include unicast, multicast, and / or broadcast.

[0165] Furthermore, in the present disclosure, a resource may be exchanged / replaced by a time slot or a symbol, and vice versa. For example, a resource may include a time slot and / or a symbol.

[0166] Furthermore, in the present disclosure, priority may be replaced / replaced by at least one of logical channel priority (LCP), latency, reliability, minimum required communication range, PPPP, side link radio bearer (SLRB), QoS profile, QoS parameters and / or requirements, and vice versa.

[0167] Furthermore, in the present disclosure, for example, for convenience of description, a (physical) channel used when an RX UE transmits at least one of the following information to a TX UE may be referred to as a PSFCH.

[0168] -SL HARQ feedback, SL CSI, SL (L1) RSRP

[0169] In addition, in the present disclosure, a Uu channel may include an UL channel and / or a DL channel. For example, an UL channel may include a PUSCH, a PUCCH, etc. For example, a DL channel may include a PDCCH, a PDSCH, etc. For example, a SL channel may include a PSCCH, a PSSCH, a PSFCH, a PSBCH, etc.

[0170] In addition, in the present disclosure, the side link information may include at least one of a side link message, a side link packet, a side link service, a side link data, a side link control information and / or a side link transport block (TB). For example, the side link information may be sent via PSSCH and / or PSCCH.

[0171] In addition, in NR SL or NR V2X, HARQ feedback between the TX UE and the RX UE can be supported. In addition, the TX UE can report the SL HARQ feedback received from the RX UE to the base station. For example, in order to request the base station to allocate additional (re)transmission resources, the TX UE can report the SL HARQ feedback received from the RX UE to the base station.

[0172] For example, SL HARQ feedback reporting may be supported as shown in Table 5.

[0173] [Table 5]

[0174]

[0175] Referring to Table 5, for example, if the base station schedules / allocates SL resources to the TX UE through DG or CG, the base station may additionally schedule / allocate PUCCH resources related to the SL resources to the TX UE. Alternatively, for example, if the base station schedules / allocates SL resources to the TX UE through DG or CG, the base station may not schedule / allocate PUCCH resources related to the SL resources to the TX UE. For example, if the base station schedules / allocates PUCCH resources related to SL resources to the TX UE, the TX UE may report the SL HARQ feedback received from the RX UE to the base station by using the PUCCH resources. For example, if the base station does not schedule / allocate PUCCH resources related to SL resources to the TX UE, the TX UE may not report the SL HARQ feedback received from the RX UE to the base station. For example, the SL resources may include at least one of PSSCH resources, PSCCH resources and / or PSFCH resources.

[0176] In addition, in NR SL or NR V2X, the TX UE can perform Logical Channel Prioritization (LCP) to obtain MAC PDUs. In addition, as shown in Table 6, HARQ enabling and / or HARQ disabling can be included in the LCP restriction.

[0177] [Table 6]

[0178]

[0179] Referring to Table 6, enabling or disabling HARQ feedback may be considered in the LCP. For example, in the case where the TX UE obtains a MAC PDU, the TX UE may obtain the MAC PDU by multiplexing only the packets for which HARQ feedback is enabled. For example, in the case where the TX UE obtains a MAC PDU, the TX UE may obtain the MAC PDU by multiplexing only the logical channels configured to enable HARQ feedback. For example, in the case where the TX UE obtains a MAC PDU, the TX UE may obtain the MAC PDU by multiplexing only the packets for which HARQ feedback is disabled. For example, in the case where the TX UE obtains a MAC PDU, the TX UE may obtain the MAC PDU by multiplexing only the logical channels configured to disable HARQ feedback. For example, the TX UE may not obtain the MAC PDU by multiplexing the packets for which HARQ feedback is disabled and the packets for which HARQ feedback is enabled. For ease of description, a MAC PDU that includes only packets for which HARQ feedback is enabled may be referred to as a HARQ-enabled MAC PDU, and a MAC PDU that includes only packets for which HARQ feedback is disabled may be referred to as a HARQ-disabled MAC PDU. For example, a HARQ-enabled MAC PDU may include logical channels configured to enable HARQ feedback, but may not include logical channels configured to disable HARQ feedback. For example, a HARQ-disabled MAC PDU may include logical channels configured to disable HARQ feedback, but may not include logical channels configured to enable HARQ feedback.

[0180] In addition, according to the current NR V2X state, in resource allocation mode 1, the base station can schedule / allocate SL resources to the TX UE through DG and / or CG. For the sake of convenience of description, the DG and / or CG used to schedule / allocate SL resources may be referred to as SL authorization. For example, if the base station schedules / allocates SL resources to the TX UE through SL authorization, the TX UE may send a HARQ-enabled MAC PDU or a HARQ-disabled MAC PDU to the RX UE by using the SL resources. For example, if the base station schedules / allocates SL resources to the TX UE through SL authorization, the TX UE may send a HARQ-enabled MAC PDU or a HARQ-disabled MAC PDU to the RX UE by using the SL resources, regardless of whether the base station schedules / allocates PUCCH resources related to the SL resources to the TX UE. That is, since there is no HARQ restriction in a specific SL authorization, the TX UE may send not only a HARQ-enabled MAC PDU or may send not only a HARQ-disabled MAC PDU by using the SL resources allocated through the SL authorization. Therefore, for example, if there are PUCCH resources associated with SL grant, the TX UE can send HARQ disabled MAC PDU to the RX UE by using the SL resources allocated by the SL grant, and the TX UE can also send SL HARQ feedback to the base station by using the PUCCH resources.

[0181] Hereinafter, based on various embodiments of the present disclosure, when the base station allocates SL resources to the TX UE through SL authorization, a method for the TX UE to send MAC PDU based on whether there are PUCCH resources related to the SL authorization and a device supporting the method will be described.

[0182] For example, the base station can schedule / allocate SL resources to the TX UE through SL authorization (e.g., DCI). For example, the TX UE can send a MAC PDU to the RX UE by using the SL resources. For example, if the MAC PDU is a HARQ-enabled MAC PDU, the TX UE can receive SL HARQ feedback related to the MAC PDU from the RX UE. For example, the TX UE can report the SL HARQ feedback to the base station by using the PUCCH resources indicated / notified through the SL authorization. Herein, for example, indicating / notifying the PUCCH resources through the SL authorization may refer to the base station indicating / notifying the TX UE of a specific configuration among the PUCCH configurations configured to the TX UE through RRC signaling through the SL authorization. For example, in the case of SL configured authorization (CG), the base station may configure / allocate PUCCH resources to the TX UE through RRC signaling. For ease of description, for example, the case where the base station allocates SL resources and PUCCH resources related to the SL resources to the TX UE through SL authorization may be referred to as case A. For example, the case where the base station allocates only SL resources to the TX UE through SL authorization but does not allocate PUCCH resources related to the SL resources to the TX UE may be referred to as case B.

[0183] 1. Scenario A

[0184] Based on the embodiments of the present disclosure, the base station can schedule / allocate SL resources and PUCCH resources related to the SL resources to the TX UE. In this case, the TX UE can send HARQ-enabled MAC PDUs and HARQ-disabled MAC PDUs to the RX UE by using the SL resources allocated from the base station through the SL grant.

[0185] For example, if the TX UE transmits a HARQ-enabled MAC PDU to the RX UE, the TX UE may not be able to successfully transmit the HARQ-enabled MAC PDU to the RX UE using the initial transmission resources and / or retransmission resources scheduled / allocated by the SL grant. In this case, the TX UE may transmit a HARQ NACK to the base station using the PUCCH resources associated with the resources scheduled / allocated by the SL grant. Accordingly, the TX UE may request resources from the base station for retransmitting the HARQ-enabled MAC PDU.

[0186] Figure 12 A process in which a TX UE requests retransmission resources when a base station allocates SL resources and PUCCH resources to the TX UE according to an embodiment of the present disclosure is shown. Figure 12 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0187] Reference Figure 12 In step S1210, the base station may send information related to SL resources and information related to PUCCH resources to the TX UE. For example, the base station may send information related to SL resources to the TX UE via SL DG (e.g., DCI). For example, the base station may send information related to PUCCH resources to the TX UE via DCI and / or RRC message.

[0188] In step S1220, the TX UE may acquire / generate a HARQ-disabled MAC PDU. For example, if the TX UE transmits a HARQ-disabled MAC PDU to the RX UE, the TX UE may transmit the HARQ-disabled MAC PDU to the RX UE using initial transmission resources and / or retransmission resources scheduled / allocated via the SL DG. For example, the base station may schedule / allocate one initial transmission resource and two retransmission resources to the TX UE via one SL DG. For example, the TX UE may perform one initial transmission and two blind retransmissions of the HARQ-disabled MAC PDU.

[0189] In step S1230, the TX UE may determine that additional retransmissions are required. In this case, for example, the TX UE may not be able to perform the necessary retransmissions by using the initial transmission resources and / or retransmission resources scheduled by the base station through one SL DG. Alternatively, for example, the TX UE may not be able to perform retransmissions for the maximum number of retransmissions by using the initial transmission resources and / or retransmission resources scheduled by the base station through one SL DG. Alternatively, for example, the TX UE may determine that there is no SL grant available for retransmissions.

[0190] In this case, in step S1240, the TX UE may transmit a HARQ NACK to the base station using PUCCH resources associated with the resources scheduled / allocated by the SL DG. Accordingly, the TX UE may request the base station for resources for retransmitting the HARQ-disabled MAC PDU. Through this operation, if the TX UE, which is performing blind retransmission of the HARQ-disabled MAC PDU, is unable to perform all necessary retransmissions, the TX UE may request the base station to allocate additional retransmission resources using PUCCH resources.

[0191] Figure 13 A process in which a TX UE requests retransmission resources when a base station allocates SL resources and PUCCH resources to the TX UE according to an embodiment of the present disclosure is shown. Figure 13 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0192] Reference Figure 13In step S1310, the base station may send information related to SL resources and information related to PUCCH resources to the TX UE. For example, the base station may send information related to SL resources to the TX UE via SL CG (e.g., DCI and / or RRC message). For example, the base station may send information related to PUCCH resources to the TX UE via DCI and / or RRC message.

[0193] In step S1320, the TX UE may acquire / generate a HARQ disabled MAC PDU. For example, if the TX UE transmits a HARQ disabled MAC PDU to the RX UE, the TX UE may transmit the HARQ disabled MAC PDU to the RX UE using initial transmission resources and / or retransmission resources scheduled / allocated by the SL CG. For example, the TX UE may perform initial transmission and blind retransmission of the HARQ disabled MAC PDU.

[0194] In step S1330, the TX UE may determine that additional retransmission is required. In this case, for example, the TX UE may not be able to perform the necessary retransmission by using the initial transmission resources and / or retransmission resources scheduled by the base station through the SL CG. Alternatively, for example, the TX UE may not be able to perform retransmission for the maximum number of retransmissions by using the initial transmission resources and / or retransmission resources scheduled by the base station through the SL CG. Alternatively, for example, if the TX UE performs retransmission by using the resources in the next cycle scheduled by the base station through the SL CG, the TX UE may determine that the TX UE did not successfully complete the SL transmission within the packet delay budget (PDB). Alternatively, for example, the TX UE may determine that there is no SL grant available for retransmission.

[0195] In this case, in step S1340, the TX UE can transmit a HARQ NACK to the base station using PUCCH resources associated with the resources scheduled / allocated by the SL CG. Accordingly, the TX UE can request resources from the base station for retransmitting the HARQ-disabled MAC PDU. Through this operation, if the TX UE, which is performing blind retransmission of the HARQ-disabled MAC PDU, is unable to perform all necessary retransmissions, the TX UE can request the base station to allocate additional retransmission resources using PUCCH resources.

[0196] Figure 14 A process in which a TX UE requests retransmission resources when a base station allocates SL resources and PUCCH resources to the TX UE according to an embodiment of the present disclosure is shown. Figure 14 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0197] Reference Figure 14 In step S1410, the base station may transmit information related to SL resources and information related to PUCCH resources to the TX UE. For example, the base station may transmit information related to SL resources and information related to PUCCH resources to the TX UE via a DG (e.g., DCI). For example, the base station may transmit information related to SL resources and information related to PUCCH resources to the TX UE via a CG (e.g., an RRC message and / or DCI).

[0198] In step S1420, the TX UE may obtain a MAC PDU. For example, the MAC PDU may include a logical channel configured to disable HARQ feedback, but may not include a logical channel configured to enable HARQ feedback. For example, the MAC PDU may include a packet related to a logical channel configured to disable HARQ feedback, but may not include a packet related to a logical channel configured to enable HARQ feedback.

[0199] In step S1430, the TX UE may transmit the PSCCH to the RX UE using the SL resources. In step S1440, the TX UE may transmit the PSSCH associated with the PSCCH to the RX UE using the SL resources. For example, the transmitting UE may transmit the obtained MAC PDU via the PSSCH.

[0200] In step S1450, the TX UE may determine that i) the MAC PDU needs to be retransmitted and ii) there are no SL resources / grants available for retransmitting the MAC PDU. For example, the TX UE may determine that SL HARQ feedback is disabled for the logical channel in the MAC PDU that needs to be retransmitted and that there are no sublink grants available for retransmitting the MAC PDU. In this case, in step S1460, the TX UE may send NACK information to the base station using PUCCH resources. Therefore, the base station may allocate additional retransmission resources to the TX UE based on the NACK information.

[0201] Based on the embodiments of the present disclosure, in the case where the TX UE sends a HARQ disabled MAC PDU to the RX UE, the TX UE can request the base station to allocate retransmission resources in advance by using pre-configured PUCCH resources. Herein, for example, the pre-configured PUCCH resources may be PUCCH resources that are unrelated to the resources scheduled by the base station through SL authorization. For example, the pre-configured PUCCH resources may be PUCCH resources allocated to the TX UE from the base station before the base station schedules SL resources to the TX UE through SL authorization. For example, pre-configured PUCCH resources for other purposes (for example, purposes other than SL HARQ feedback reporting purposes) have been allocated to the TX UE from the base station, but the TX UE may not have used the pre-configured PUCCH resources yet. Alternatively, for example, the TX UE is going to use the pre-configured PUCCH resources for other purposes, but the TX UE can use the pre-configured PUCCH resources to ensure retransmission resources in advance. For example, in order for the TX UE to perform the above operations, the TX UE can request the base station to retransmit resources by using any PUCCH resources located after the time when the SL authorization is received from the base station. That is, the TX UE can request retransmission resources from the base station by using any PUCCH resources available after receiving the SL grant from the base station. In this case, for example, the TX UE may determine / anticipate that the TX UE cannot perform all retransmissions or as many retransmissions as the maximum number of retransmissions using the SL resources allocated from the base station via the SL grant. Alternatively, for example, the TX UE may perform the above operation only when the maximum number of retransmissions configured for the MAC PDU to be transmitted by the TX UE is equal to or greater than a specific number.

[0202] For example, in the case where the TX UE sends a HARQ-enabled MAC PDU or a HARQ-disabled MAC PDU to the RX UE, the TX UE may report the SL HARQ feedback to the base station by using the PUCCH resources associated with the SL grant (e.g., the PUCCH resources indicated by the SL grant). In this case, the TX UE may send the SL HARQ feedback to the base station by using the PUCCH, taking into account the packet delay budget (PDB) of the HARQ-enabled MAC PDU or the HARQ-disabled MAC PDU. For example, if the TX UE that intends to request additional retransmission resources through the PUCCH determines that the TX UE cannot send SL information within the PDB by using the additional retransmission resources allocated from the base station, the TX UE may not report the SL HARQ feedback to the base station. For example, if the TX UE that intends to request additional retransmission resources through the PUCCH determines that the TX UE is able to send SL information within the PDB by using the additional retransmission resources allocated from the base station, the TX UE may report the SL HARQ feedback to the base station by using the PUCCH resources. In addition, the base station may allocate additional retransmission resources to the TX UE based on SL HARQ feedback (eg, HARQ NACK).

[0203] 2. Scenario B

[0204] Based on the embodiments of the present disclosure, the base station may schedule / allocate only SL resources to the TX UE. On the other hand, the base station may not schedule / allocate PUCCH resources related to the SL resources to the TX UE. In this case, the TX UE can send HARQ-enabled MAC PDUs and HARQ-disabled MAC PDUs to the RX UE by using the SL resources allocated from the base station through the SL grant.

[0205] In this case, for example, if the TX UE sends a HARQ-enabled MAC PDU and / or a HARQ-disabled MAC PDU to the RX UE, the TX UE may not be able to request additional retransmission resources from the base station. For example, if the maximum number of retransmissions of the TX UE is 10, if the base station allocates a maximum of 3 resources to the TX UE through the SL DG, the TX UE may not be able to perform the remaining 7 transmissions. Naturally, the TX UE and the base station know the maximum number of retransmissions each other, and the TX UE can expect to receive multiple SL DGs from the base station to meet all the maximum number of retransmissions. However, due to the resource scheduling burden of the base station, the base station may not be able to send multiple SL DGs to the TX UE. In this case, the TX UE may have to find a way to request additional resources. If the TX UE cannot request additional resources, the TX UE may not be able to perform additional retransmissions. Therefore, in case B, a method for the TX UE to request additional retransmission resources from the base station and a device supporting the method or an optimization method of the UE and a device supporting the method are proposed.

[0206] First, a restriction is proposed that allows a TX UE to use a SL grant that does not indicate PUCCH resources. For example, the TX UE may perform SL transmission using SL resources allocated using a SL grant that does not indicate PUCCH resources only when the maximum number of retransmissions of the MAC PDU to be transmitted by the TX UE or the number of retransmissions configured by the TX UE is less than a specific number or a specific threshold. In this case, since the base station does not allocate PUCCH resources related to the SL resources to the TX UE, the TX UE may not be able to report SL HARQ feedback to the base station.

[0207] For example, the SL DG (e.g., DCI) sent by the base station to the TX UE in resource allocation mode 1 can schedule resources associated with one initial transmission and resources associated with two retransmissions to the TX UE at most. That is, the SL DG can schedule resources associated with a total of three transmissions to the TX UE. Therefore, if the number of retransmissions of the MAC PDU to be sent by the TX UE is less than three, the TX UE can perform SL transmission by using SL resources allocated by SL grant that does not indicate PUCCH resources. Naturally, the above-mentioned limit can be fixedly set to two retransmissions, but can be set differently according to the channel conditions or congestion level of the TX UE. By the above-mentioned limit, the problem that the TX UE cannot further request additional retransmission resources from the base station by using PUCCH resources can be prevented.

[0208] Alternatively, for example, it is assumed that the base station sends a SL grant that does not indicate PUCCH resources to the TX UE, and the TX UE sends a MAC PDU to the RX UE by using the SL resources allocated by the SL grant. In addition, it is assumed that even if the TX UE has used all the SL resources allocated by the SL grant, the TX UE requires additional retransmission resources. For example, it is assumed that even if all the SL resources allocated by the SL grant have been used, the TX UE cannot reach the maximum number of retransmissions of the TX UE, and therefore, the TX UE requires additional retransmission resources. Therefore, the TX UE can trigger a new scheduling request (SR) and / or buffer status report (BSR) process. For example, the TX UE can send the SR and / or BSR to the base station.

[0209] In the above situation, the TX UE may send a new SR to the base station, but may not send a BSR to the base station. For example, since the BSR may be replaced by the BSR performed in the previous initial transmission, the TX UE may send a new SR to the base station, but may not send a BSR to the base station. In other words, the TX UE may not repeatedly send a BSR to the base station to request additional retransmission resources for the initial transmission. In addition, for example, the base station may allocate resources to the TX UE based on the BSR previously sent by the TX UE.

[0210] According to various embodiments of the present disclosure, if a UE cannot perform SL retransmission using resources allocated from a base station, the UE may request retransmission resources from the base station to perform additional SL retransmission. Specifically, if PUCCH resources are allocated to the UE from the base station, even if the UE has transmitted an HARQ-disabled MAC PDU, if the UE determines that there is no SL grant available for retransmission, the UE may send NACK information to the base station via the PUCCH. Therefore, there may be an effect that additional retransmission resources can be allocated from the base station to the UE.

[0211] Figure 15 A method for performing wireless communication by a first device according to an embodiment of the present disclosure is shown. Figure 15 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0212] Reference Figure 15, in step S1510, the first device may receive information related to a first sublink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station. In step S1520, the first device may send a medium access control (MAC) packet data unit (PDU) to the second device by using the first SL resource. For example, the MAC PDU may include packets related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and the MAC PDU may not include packets related to a logical channel for which HARQ feedback is enabled. In step S1530, the first device may determine that the MAC PDU needs to be retransmitted. In step S1540, the first device may send NACK information to the base station by using the first PUCCH resource based on the absence of SL authorization available for retransmitting the MAC PDU.

[0213] For example, the first PUCCH resource may be a resource associated with the first SL resource. For example, NACK information may be sent to request resources for retransmitting the MAC PDU from the base station. Furthermore, for example, the first device may receive information associated with the second SL resource from the base station in response to the NACK information. Furthermore, for example, the first device may retransmit the MAC PDU to the second device using the second SL resource.

[0214] For example, a logical channel for which HARQ feedback is disabled and a logical channel for which HARQ feedback is enabled cannot be multiplexed in a MAC PDU at the same time.

[0215] Additionally, for example, based on transmitting the MAC PDU to the second device, the first device may transmit information related to the request for retransmission resources to the base station using a second PUCCH resource. For example, the second PUCCH resource may be a resource unrelated to the first SL resource. For example, before the first device determines that the MAC PDU needs to be retransmitted, the information related to the request for retransmission resources may be transmitted to the base station.

[0216] For example, the first SL resource may include a PSCCH resource and a PSSCH resource. For example, the first SL resource may include at least one of a resource for initial transmission and a resource for retransmission. For example, information related to the first SL resource may be received via an SL grant. For example, the SL grant may be a dynamic grant or a configured grant.

[0217] The proposed method can be applied to the following devices. First, the processor 102 of the first device 100 can control the transceiver 106 to receive information related to a first sublink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station. In addition, the processor 102 of the first device 100 can control the transceiver 106 to send a medium access control (MAC) packet data unit (PDU) to the second device by using the first SL resource. For example, the MAC PDU may include packets related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and the MAC PDU may not include packets related to a logical channel for which HARQ feedback is enabled. In addition, the processor 102 of the first device 100 may determine that the MAC PDU needs to be retransmitted. In addition, the processor 102 of the first device 100 may control the transceiver 106 to send NACK information to the base station by using the first PUCCH resource based on the absence of SL authorization available for retransmitting the MAC PDU.

[0218] Based on an embodiment of the present disclosure, a first device configured to perform wireless communication may be provided. For example, the first device may include: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: receive information related to a first secondary link (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station; send a medium access control (MAC) packet data unit (PDU) to a second device by using the first SL resource, wherein the MAC PDU includes a packet related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and wherein the MAC PDU does not include a packet related to a logical channel for which HARQ feedback is enabled; determine that the MAC PDU needs to be retransmitted; and based on the absence of an SL grant available for retransmitting the MAC PDU, send NACK information to the base station by using the first PUCCH resource.

[0219] Based on an embodiment of the present disclosure, a device configured to control a first user equipment (UE) performing wireless communication may be provided. For example, the device may include: one or more processors; and one or more memories, the one or more memories being operably connected to the one or more processors and storing instructions. For example, the one or more processors may execute the instructions to: receive information related to a first sublink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station; send a medium access control (MAC) packet data unit (PDU) to a second UE by using the first SL resource, wherein the MAC PDU includes a packet related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and wherein the MAC PDU does not include a packet related to a logical channel for which HARQ feedback is enabled; determine that the MAC PDU needs to be resent; and based on the absence of an SL grant available for resending the MAC PDU, send NACK information to the base station by using the first PUCCH resource.

[0220] Based on an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be provided. For example, when the instructions are executed, a first device may cause the first device to: receive information related to a first sublink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource from a base station; send a medium access control (MAC) packet data unit (PDU) to a second UE by using the first SL resource, wherein the MAC PDU includes a packet related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and wherein the MAC PDU does not include a packet related to a logical channel for which HARQ feedback is enabled; determine that the MAC PDU needs to be resent; and based on the absence of an SL authorization available for resending the MAC PDU, send NACK information to the base station by using the first PUCCH resource.

[0221] Various embodiments of the present disclosure may be combined with each other.

[0222] Hereinafter, devices to which various embodiments of the present disclosure can be applied will be described.

[0223] The various descriptions, functions, processes, proposals, methods and / or operational flows of the present disclosure described in this document may be applied to, but not limited to, various fields requiring wireless communication / connection between devices (e.g., 5G).

[0224] Hereinafter, a more detailed description will be given with reference to the accompanying drawings. In the following drawings / descriptions, unless otherwise described, the same reference numerals may represent the same or corresponding hardware blocks, software blocks or functional blocks.

[0225] Figure 16 A communication system (1) according to an embodiment of the present disclosure is shown.

[0226] Reference Figure 16 , a communication system (1) to which various embodiments of the present disclosure are applied includes a wireless device, a base station (BS), and a network. Herein, a wireless device refers to a device that performs communication using a radio access technology (RAT) (e.g., 5G New RAT (NR) or Long Term Evolution (LTE)), and may be referred to as a communication / radio / 5G device. The wireless device may include, but is not limited to, a robot (100a), a vehicle (100b-1, 100b-2), an extended reality (XR) device (100c), a handheld device (100d), a home appliance (100e), an Internet of Things (IoT) device (100f), and an artificial intelligence (AI) device / server (400). For example, a vehicle may include a vehicle with a wireless communication function, an autonomous vehicle, and a vehicle capable of performing inter-vehicle communication. Herein, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. Handheld devices may include smartphones, smart boards, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., notebooks). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters. For example, a BS and a network may be implemented as wireless devices, and a specific wireless device (200a) may operate as a BS / network node relative to other wireless devices.

[0227] Wireless devices 100a to 100f can be connected to a network 300 via a BS 200. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can be connected to an AI server 400 via the network 300. The network 300 can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although wireless devices 100a to 100f can communicate with each other via the BS 200 / network 300, wireless devices 100a to 100f can perform direct communication (e.g., sidelink communication) with each other without going through the BS / network. For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0228] Wireless communication / connection 150a, 150b, or 150c can be established between wireless devices 100a to 100f / BS 200 or BS 200 / BS 200. Here, the wireless communication / connection can be established via various RATs (e.g., 5G NR), such as uplink / downlink communication 150a, sidelink communication 150b (or D2D communication), or inter-BS communication (e.g., relay, integrated access backhaul (IAB)). The wireless device and the BS / wireless device can send / receive radio signals to / from each other via wireless communication / connection 150a and 150b. For example, wireless communication / connection 150a and 150b can send / receive signals via various physical channels. To this end, various configuration information configuration processes for transmitting / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of the resource allocation process can be performed based on various proposals of the present disclosure.

[0229] Figure 17 A wireless device according to an embodiment of the present disclosure is shown.

[0230] Reference Figure 17 , the first wireless device (100) and the second wireless device (200) can transmit radio signals through various RATs (e.g., LTE and NR). Herein, {the first wireless device (100) and the second wireless device (200)} may correspond to Figure 16 {wireless device (100x) and BS (200)} and / or {wireless device (100x) and wireless device (100x)} in.

[0231] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and may additionally further include one or more transceivers 106 and / or one or more antennas 108. The processor(s) 102 may control the memory(s) 104 and / or the transceiver(s) 106, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed herein. For example, the processor(s) 102 may process information in the memory(s) 104 to generate first information / signals, and then transmit a radio signal including the first information / signals through the transceiver(s) 106. The processor(s) 102 may receive a radio signal including second information / signals through the transceiver 106, and then store information obtained by processing the second information / signals in the memory(s) 104. The memory(s) 104 may be connected to the processor(s) 102 and may store various information related to the operation of the processor(s) 102. For example, the memory(s) 104 may store software code including instructions for executing part or all of the processing controlled by the processor(s) 102 or for executing the descriptions, functions, procedures, proposals, methods, and / or operational flows disclosed in this document. Here, the processor(s) 102 and the memory(s) 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver(s) 106 may be connected to the processor(s) 102 and transmit and / or receive radio signals via the antenna(s) 108. Each transceiver 106 may include a transmitter and / or a receiver. The transceiver(s) 106 may be used interchangeably with the radio frequency (RF) unit(s). In the present disclosure, a wireless device may represent a communication modem / circuit / chip.

[0232] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and may additionally further include one or more transceivers 206 and / or one or more antennas 208. The processor(s) 202 may control the memory(s) 204 and / or the transceiver(s) 206, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed herein. For example, the processor(s) 202 may process information in the memory(s) 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver(s) 206. The processor(s) 202 may receive a radio signal including fourth information / signals through the transceiver(s) 106, and then store information obtained by processing the fourth information / signals in the memory(s) 204. The memory(s) 204 may be connected to the processor(s) 202 and may store various information related to the operation of the processor(s) 202. For example, the memory(s) 204 may store software code including instructions for executing part or all of the processing controlled by the processor(s) 202 or for executing the descriptions, functions, procedures, proposals, methods, and / or operational flows disclosed in this document. Here, the processor(s) 202 and the memory(s) 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver(s) 206 may be connected to the processor(s) 202 and transmit and / or receive radio signals via the antenna(s) 208. Each transceiver 206 may include a transmitter and / or a receiver. The transceiver(s) 206 may be used interchangeably with the RF unit(s). In the present disclosure, a wireless device may represent a communication modem / circuit / chip.

[0233] The hardware elements of wireless devices 100 and 200 will be described in more detail below. One or more protocol layers may be, but are not limited to, implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). One or more processors 102 and 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, proposals, methods, and / or operational flows disclosed herein. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flows disclosed herein. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flows disclosed herein, and provide the generated signals to one or more transceivers 106 and 206. One or more processors 102 and 202 can receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document.

[0234] The one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For 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 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. The firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document may be included in the one or more processors 102 and 202 or stored in one or more memories 104 and 204, thereby being driven by the one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document may be implemented using software or firmware in the form of code, commands, and / or command sets.

[0235] One or more memories 104 and 204 can be connected to one or more processors 102 and 202 and can store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 can be composed of read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard drive, registers, cash memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 can be located internally and / or externally to one or more processors 102 and 202. One or more memories 104 and 204 can be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0236] One or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels described in the methods and / or operational flows of this document to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels described in the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and may transmit and receive radio signals. For example, one or more processors 102 and 202 may control the one or more transceivers 106 and 206 to transmit user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may control the one or more transceivers 106 and 206 to receive user data, control information, or radio signals from one or more other devices. One or more transceivers 106 and 206 can be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 can be configured to transmit and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document via one or more antennas 108 and 208. In this document, one or more antennas can be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 can convert received radio signals / channels, etc. from RF band signals to baseband signals so that the received user data, control information, radio signals / channels, etc. can be processed by one or more processors 102 and 202. One or more transceivers 106 and 206 can convert the user data, control information, radio signals / channels, etc. processed by one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more transceivers 106 and 206 can include (analog) oscillators and / or filters.

[0237] Figure 18 A signal processing circuit for transmitting a signal according to an embodiment of the present disclosure is shown.

[0238] Reference Figure 18 , the signal processing circuit (1000) may include a scrambler (1010), a modulator (1020), a layer mapper (1030), a precoder (1040), a resource mapper (1050) and a signal generator (1060). Figure 18 operations / functions, not limited to Figure 17 The processor (102, 202) and / or transceiver (106, 206) of Figure 17The processor (102, 202) and / or transceiver (106, 206) are implemented Figure 18 For example, you can Figure 17 Alternatively, the processor (102, 202) can implement blocks 1010 to 1060. Figure 17 The processor (102, 202) implements blocks 1010 to 1050 and can be implemented by Figure 17 The transceiver (106, 206) is used to implement block 1060.

[0239] Can be passed Figure 18 The signal processing circuit (1000) converts the codeword into a radio signal. In this article, the codeword is a coded bit sequence of an information block. The information block may include a transport block (e.g., UL-SCH transport block, DL-SCH transport block). The radio signal may be transmitted via various physical channels (e.g., PUSCH and PDSCH).

[0240] Specifically, the codeword can be converted into a scrambled bit sequence by the scrambler 1010. The scrambling sequence for scrambling can be generated based on an initial value, and the initial value can include the ID information of the wireless device. The scrambled bit sequence can be modulated into a modulation symbol sequence by the modulator 1020. The modulation scheme may include pi / 2-binary phase shift keying (pi / 2-BPSK), m-phase shift keying (m-PSK), and m-quadrature amplitude modulation (m-QAM). The complex modulation symbol sequence can be mapped to one or more transmission layers by the layer mapper 1030. The modulation symbol of each transmission layer can be mapped (precoded) to (one or more) corresponding antenna ports by the precoder 1040. The output z of the precoder 1040 can be obtained by multiplying the output y of the layer mapper 1030 with the N*M precoding matrix W. Here, N is the number of antenna ports and M is the number of transmission layers. The precoder 1040 can perform precoding after performing transform precoding (e.g., DFT) on the complex modulation symbols. Alternatively, the precoder 1040 may perform precoding without performing transform precoding.

[0241] The resource mapper 1050 can map the modulation symbols of each antenna port to time-frequency resources. The time-frequency resources may include multiple symbols in the time domain (e.g., CP-OFDMA symbols and DFT-s-OFDMA symbols) and multiple subcarriers in the frequency domain. The signal generator 1060 can generate a radio signal from the mapped modulation symbols, and the generated radio signal can be sent to other devices through each antenna. To this end, the signal generator 1060 may include an inverse fast Fourier transform (IFFT) module, a cyclic prefix (CP) inserter, a digital-to-analog converter (DAC), and an upconverter.

[0242] Can be used with Figure 18 The signal processing process for the signal received in the wireless device is configured in a manner opposite to the signal processing process (1010-1060) of the wireless device. Figure 17 100, 200) can receive a radio signal from the outside through an antenna port / transceiver. The received radio signal can be converted into a baseband signal by a signal restorer. To this end, the signal restorer may include a frequency downlink converter, an analog-to-digital converter (ADC), a CP remover, and a fast Fourier transform (FFT) module. Next, the baseband signal can be restored to a codeword through a resource demapping process, a post-coding process, a demodulation processor, and a descrambling process. The codeword can be restored to the original information block by decoding. Therefore, a signal processing circuit (not shown) for receiving a signal may include a signal restorer, a resource demapper, a post-coding process, a demodulator, a descrambler, and a decoder.

[0243] Figure 19 Another example of a wireless device according to an embodiment of the present disclosure is shown. The wireless device can be implemented in various forms according to use cases / services (see Figure 16 ).

[0244] Reference Figure 19 , the wireless device (100, 200) may correspond to Figure 17 The wireless devices (100, 200) may be configured by various elements, components, units / portions, and / or modules. For example, each of the wireless devices (100, 200) may include a communication unit (110), a control unit (120), a memory (130), and additional components (140). The communication unit may include a communication circuit (112) and (one or more) transceivers (114). For example, the communication circuit (112) may include Figure 17 One or more processors (102, 202) and / or one or more memories (104, 204). For example, the transceiver(s) (114) may include Figure 17The control unit (120) is electrically connected to the communication unit (110), the memory (130), and the additional components (140), and controls the overall operation of the wireless device. For example, the control unit (120) can control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory (130). The control unit (120) can transmit information stored in the memory (130) to the outside (e.g., other communication devices) via the communication unit (110) through a wireless / wired interface, or store information received from the outside (e.g., other communication devices) via the communication unit (110) through a wireless / wired interface in the memory (130).

[0245] The additional component (140) may be configured in various ways depending on the type of wireless device. For example, the additional component (140) may include at least one of a power unit / battery, an input / output (I / O) unit, a drive unit, and a computing unit. The wireless device may be implemented in the following forms without limitation: a robot ( Figure 16 100a), vehicles ( Figure 16 100b-1 and 100b-2), XR devices ( Figure 16 100c), handheld device ( Figure 16 100d), household appliances ( Figure 16 100e), IoT devices ( Figure 16 100f), digital broadcasting terminal, hologram device, public safety device, MTC device, medical device, fintech device (or financial device), security device, climate / environmental device, AI server / device ( Figure 16 400), BS( Figure 16 200), network nodes, etc. Depending on the use case / service, the wireless device can be used in a mobile or fixed place.

[0246] exist Figure 19In the embodiment of the present invention, the various elements, components, units / parts and / or modules in the wireless device (100, 200) can all be connected to each other through a wired interface, or at least part of them can be connected wirelessly through the communication unit (110). For example, in each of the wireless devices (100, 200), the control unit (120) and the communication unit (110) can be connected through a wired interface, and the control unit (120) and the first unit (e.g., 130, 140) can be connected wirelessly through the communication unit (110). Each element, component, unit / part and / or module in the wireless device (100, 200) can also include one or more elements. For example, the control unit (120) can be constructed by a collection of one or more processors. As an example, the control unit (120) can be constructed by a collection of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing unit and a memory control processor. As another example, the memory ( 130 ) may be constructed by random access memory (RAM), dynamic RAM (DRAM), read only memory (ROM), flash memory, volatile memory, nonvolatile memory, and / or combinations thereof.

[0247] Hereinafter, the implementation will be described in detail with reference to the accompanying drawings. Figure 19 .

[0248] Figure 19 A handheld device according to an embodiment of the present disclosure is shown. The handheld device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or smart glasses), or a portable computer (e.g., a notebook). The handheld device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).

[0249] Reference Figure 20 The handheld device (100) may include an antenna unit (antenna) (108), a communication unit (110), a control unit (120), a memory (130), a power supply unit (140a), an interface unit (140b) and an I / O unit (140c). The antenna unit (108) may be configured as a part of the communication unit (110). Blocks 110 to 130 / 140a to 140c correspond to Figure 19 Frame 110 to 130 / 140.

[0250] The communication unit 110 can send and receive signals (e.g., data signals and control signals) to and from other wireless devices or a base station. The control unit 120 can perform various operations by controlling the components of the handheld device 100. The control unit 120 may include an application processor (AP). The memory 130 can store data / parameters / programs / codes / commands required to operate the handheld device 100. The memory 130 can store input / output data / information. The power supply unit 140a can supply power to the handheld device 100 and may include wired / wireless charging circuits, a battery, etc. The interface unit 140b can support connection between the handheld device 100 and other external devices. The interface unit 140b may include various ports for connecting to external devices (e.g., an audio I / O port and a video I / O port). The I / O unit 140c can input or output user-input video information / signals, audio information / signals, data, and / or information. The I / O unit 140c may include a camera, a microphone, a user input unit, a display unit 140d, a speaker, and / or a haptic module.

[0251] For example, in the case of data communication, the I / O unit 140c can obtain information / signals (e.g., touch, text, voice, image, or video) input by the user, and the obtained information / signals can be stored in the memory 130. The communication unit 110 can convert the information / signals stored in the memory into radio signals and transmit the converted radio signals directly to other wireless devices or to the BS. The communication unit 110 can receive radio signals from other wireless devices or BSs and then restore the received radio signals to the original information / signals. The restored information / signals can be stored in the memory 130 and can be output as various types (e.g., text, voice, image, video, or tactile) through the I / O unit 140.

[0252] Figure 21 A vehicle or autonomous vehicle according to an embodiment of the present disclosure is shown. The vehicle or autonomous vehicle can be implemented by a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0253] Reference Figure 21 , the vehicle or autonomous vehicle (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a drive unit (140a), a power supply unit (140b), a sensor unit (140c) and an autonomous driving unit (140d). The antenna unit (108) may be configured as a part of the communication unit (110). Blocks 110 / 130 / 140a to 140d correspond to Figure 19 Box 110 / 130 / 140.

[0254] The communication unit 110 can send and receive signals (e.g., data signals and control signals) to and from external devices such as other vehicles, base stations (e.g., gNBs and roadside units), and servers. The control unit 120 can perform various operations by controlling components of the vehicle or autonomous vehicle 100. The control unit 120 may include an electronic control unit (ECU). The drive unit 140a can cause the vehicle or autonomous vehicle 100 to travel on the road. The drive unit 140a may include an engine, a motor, a transmission system, wheels, brakes, a steering system, etc. The power supply unit 140b can supply power to the vehicle or autonomous vehicle 100 and may include a wired / wireless charging circuit, a battery, etc. The sensor unit 140c can obtain vehicle status, external environment information, user information, etc. The sensor unit 140 c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a location module, a vehicle forward / backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, a lighting sensor, a pedal position sensor, etc. The autonomous driving unit 140 d may implement a technology for maintaining a lane in which the vehicle is traveling, a technology for automatically adjusting the speed (e.g., adaptive cruise control), a technology for autonomously driving along a determined path, a technology for driving by automatically setting a path with a destination set, etc.

[0255] For example, the communication unit 110 can receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d can generate an autonomous driving path and driving plan based on the acquired data. The control unit 120 can control the drive unit 140a so that the vehicle or autonomous driving vehicle 100 can move along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit 110 can aperiodically / periodically acquire the latest traffic information data from the external server and acquire surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c can acquire vehicle status and / or surrounding environment information. The autonomous driving unit 140d can update the autonomous driving path and driving plan based on the newly acquired data / information. The communication unit 110 can transmit information about the vehicle's location, autonomous driving path, and / or driving plan to the external server. The external server can use AI technology, etc. based on the information collected from the vehicle or autonomous driving vehicle to predict traffic information data and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0256] The claims in this specification can be combined in various ways. For example, the technical features in the method claims of this specification can be combined to be implemented or performed in a device, and the technical features in the device claims can be combined to be implemented or performed in a method. In addition, the technical features in (one or more) method claims and (one or more) device claims can be combined to be implemented or performed in a device. In addition, the technical features in (one or more) method claims and (one or more) device claims can be combined to be implemented or performed in a method.

Claims

1. A method for performing wireless communication by a first device, the method comprising the steps of: receiving, from a base station, information related to a secondary link (SL) resource and information related to a physical uplink control channel (PUCCH) resource; constructing a medium access control MAC packet data unit PDU for which hybrid automatic repeat request HARQ feedback is disabled, wherein the MAC PDU includes one or more packets associated with one or more logical channels for which HARQ feedback is disabled and does not include any packets associated with logical channels for which HARQ feedback is enabled; sending the MAC PDU to a second device based on the SL resource; determining that retransmission of the MAC PDU is required; and Based on i) disabling HARQ feedback for the MAC PDU, and ii) no SL grant is available for the retransmission of the MAC PDU, sending a negative acknowledgement (NACK) on the PUCCH resource to the base station.

2. The method according to claim 1, wherein The PUCCH resource is a resource related to the SL resource.

3. The method according to claim 1, wherein The NACK is sent to request resources for the retransmission of the MAC PDU from the base station.

4. The method according to claim 1, further comprising the steps of: After sending the NACK to the base station, information related to additional SL resources is received from the base station.

5. The method according to claim 4, further comprising the steps of: The MAC PDU is resent to the second device by using the additional SL resources.

6. The method according to claim 1, wherein The one or more logical channels for which HARQ feedback is disabled and the one or more logical channels for which HARQ feedback is enabled are not multiplexed simultaneously in the MAC PDU.

7. The method according to claim 1, further comprising the steps of: Based on transmitting the MAC PDU to the second device, transmitting information related to a request for retransmission resources to the base station by using a PUCCH resource not related to the SL resource, Wherein, before the first device determines that the retransmission of the MAC PDU is required, the information related to the request for the retransmission resources is sent to the base station.

8. The method according to claim 1, wherein The SL resources include physical secondary link control channel PSCCH resources and physical secondary link shared channel PSSCH resources.

9. The method according to claim 1, wherein The SL resources include at least one of resources for initial transmission or resources for retransmission.

10. The method according to claim 1, wherein The information related to the SL resource is received via SL authorization, and The SL authorization is dynamic authorization or configuration authorization.

11. A first device configured to perform wireless communication, the first device comprising: one or more memories storing instructions; one or more transceivers; as well as one or more processors connected to the one or more memories and the one or more transceivers, wherein the one or more processors execute the instructions to: receiving, from a base station, information related to a secondary link (SL) resource and information related to a physical uplink control channel (PUCCH) resource; constructing a medium access control MAC packet data unit PDU for which hybrid automatic repeat request HARQ feedback is disabled, wherein the MAC PDU includes one or more packets associated with one or more logical channels for which HARQ feedback is disabled and does not include any packets associated with logical channels for which HARQ feedback is enabled; sending the MAC PDU to a second device based on the SL resource; determining that retransmission of the MAC PDU is required; and Based on i) disabling HARQ feedback for the MAC PDU, and ii) no SL grant is available for the retransmission of the MAC PDU, sending a negative acknowledgement (NACK) on the PUCCH resource to the base station.

12. A device configured to control a first user equipment (UE) performing wireless communication, the device comprising: one or more processors; as well as one or more memories operatively connected to the one or more processors and storing instructions, wherein the one or more processors execute the instructions to: receiving, from a base station, information related to a secondary link (SL) resource and information related to a physical uplink control channel (PUCCH) resource; constructing a medium access control MAC packet data unit PDU for which hybrid automatic repeat request HARQ feedback is disabled, wherein the MAC PDU includes one or more packets associated with one or more logical channels for which HARQ feedback is disabled and does not include any packets associated with logical channels for which HARQ feedback is enabled; sending the MAC PDU to a second device based on the SL resource; determining that retransmission of the MAC PDU is required; and Based on i) disabling HARQ feedback for the MAC PDU, and ii) no SL grant is available for the retransmission of the MAC PDU, sending a negative acknowledgement (NACK) on the PUCCH resource to the base station.

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