Method and apparatus for performing sidelink retransmission in a wireless communication system

Abstract

A method for performing wireless communication by a first device is proposed. The method may include the following steps: the first device performs at least one sidelink transmission to a second device; receives negative acknowledgement (NACK) information related to the at least one sidelink transmission from the second device; and determines whether to transmit a message for requesting retransmission resources based on a remaining waiting time budget related to the at least one sidelink transmission and a preset waiting time threshold.

Description

Technical Field

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

[0002] Sidelink (SL) communication is a communication scheme in which a direct link is established between user equipments (UEs) and the UEs directly exchange voice and data 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 objects equipped with infrastructure. V2X can be divided into four types such as V2V (Vehicle to Vehicle), V2I (Vehicle to Infrastructure), V2N (Vehicle to Network), and V2P (Vehicle to Pedestrian). V2X communication can be provided through the PC5 interface and / or the Uu interface.

[0004] In addition, as more and more communication devices require larger communication capacity, mobile broadband communication enhanced relative to traditional radio access technology (RAT) is required. Therefore, the design of communication systems taking into account UEs or services that are sensitive to reliability and latency has also been discussed, and the next generation radio access technology taking into account enhanced mobile broadband communication, massive MTC, and ultra-reliable low-latency communication (URLLC) can be referred to as a new RAT (radio access technology) or NR (new radio).

[0005] Figure 1 is a diagram for describing NR-based V2X communication compared with V2X communication based on a RAT 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 the RAT used before NR, the focus is on the scheme of providing safety services based on V2X messages such as BSM (Basic Safety Message), CAM (Cooperative Awareness Message) and DENM (Decentralized Environment Notification Message). V2X messages may include location information, dynamic information, attribute information, etc. For example, a UE may transmit a periodic message type CAM and / or an event-triggered message type DENM to another UE.

[0007] For example, CAM may include dynamic state information of the vehicle such as direction and speed, static data of the vehicle such as size, and basic vehicle information such as external lighting status, route details, etc. For example, UE may broadcast CAM, and the latency of CAM may be less than 100ms. For example, UE may generate DENM and transmit it to another UE in unexpected situations such as vehicle failure, accident, etc. For example, all vehicles within the transmission range of UE can receive CAM and / or DENM. In this case, DENM may have a higher priority than CAM.

[0008] Since then, various V2X scenarios have been proposed in NR regarding V2X communication, such as vehicle platooning, advanced driving, extended sensors, remote driving, etc.

[0009] For example, based on the vehicle queuing, the vehicles can move together by dynamically forming a group. For example, in order to perform a queuing operation based on the vehicle queuing, the vehicles belonging to the group can receive periodic data from the leading vehicle. For example, the vehicles belonging to the group can reduce or increase the interval between the vehicles by using the periodic data.

[0010] For example, based on advanced driving, the vehicles can be semi-autonomous or fully autonomous. For example, each vehicle can adjust 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 by local sensors can be exchanged between the vehicle, the logical entity, the pedestrian UE and / or the V2X application server, so that, for example, the vehicle can recognize a further improved environment compared to the environment detected using its own sensors.

[0012] For example, based on remote driving, for a person or remote vehicle that cannot drive in a dangerous environment, a remote driver or V2X application can operate or control the remote vehicle. For example, if the route is predictable (such as public transportation), cloud computing-based driving can be used for the operation or control of the remote vehicle. In addition, for example, access to a cloud-based backend service platform can be considered for remote driving.

[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 communications. Summary of the invention

[0014] Technical issues

[0015] Meanwhile, in the case of a side link in the next communication system, at least two side link modes may be defined. For example, in the case of NR side link mode 1, the base station may schedule side link resources to be used by the UE for side link transmission. For example, in the case of NR side link mode 2, the UE may determine the side link transmission resources within the side link resources configured by the base station / network or the pre-configured side link resources. The configured side link resources or the pre-configured side link resources may be a resource / resource pool. At this point, when the UE performs a side link retransmission to another UE, the side link retransmission may be delayed due to a scheduling request and / or a buffer status report for receiving resource allocation from the base station.

[0016] Technical Solution

[0017] In an embodiment, a method of performing wireless communication by a first apparatus 100 is provided. The method may include performing at least one sidelink transmission to a second device, receiving negative acknowledgement (NACK) information related to the at least one sidelink transmission from the second device, and determining whether to transmit a message for requesting retransmission resources based on a remaining wait time budget related to the at least one sidelink transmission and a preconfigured delay time threshold.

[0018] Effects of the Invention

[0019] A user equipment (UE) can efficiently perform sidelink communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a diagram for describing NR-based V2X communication compared with V2X communication based on a RAT used before NR.

[0021] Figure 2 The structure of the NR system according to an embodiment of the present disclosure is shown.

[0022] Figure 3 The functional division between NG-RAN and 5GC according to an embodiment of the present disclosure is shown.

[0023] Figure 4 A radio protocol architecture according to an embodiment of the present disclosure is shown.

[0024] Figure 5 The structure of the NR system according to an embodiment of the present disclosure is shown.

[0025] Figure 6 The structure of the time slot of the NR frame according to an embodiment of the present disclosure is shown.

[0026] Figure 7 An example of a BWP according to an embodiment of the present disclosure is shown.

[0027] Figure 8 A radio protocol architecture for SL communication according to an embodiment of the present disclosure is shown.

[0028] Fig. 9 A UE performing V2X or SL communication according to an embodiment of the present disclosure is shown.

[0029] Fig.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.

[0030] Fig.11 Three cast types are shown according to an embodiment of the present disclosure.

[0031] Fig.12 A process in which a UE performs sidelink retransmission based on retransmission resources according to an embodiment of the present disclosure is shown.

[0032] Fig.13 The process of UE stopping sidelink retransmission according to an embodiment of the present disclosure is shown.

[0033] Fig.14 It shows a process in which the UE continues to perform sidelink retransmission according to an embodiment of the present disclosure.

[0034] Fig.15 A process for performing sidelink communication by a UE configured with both sidelink resource allocation mode 1 and sidelink resource allocation mode 2 according to an embodiment of the present disclosure is shown.

[0035] Fig.16 A method for a first device 100 to perform sidelink retransmission to a second device 200 according to an embodiment of the present disclosure is shown.

[0036] Fig.17 A method for the first device 100 to stop sidelink retransmission to the second device 200 according to an embodiment of the present disclosure is shown.

[0037] Fig.18 A communication system 1 according to an embodiment of the present disclosure is shown.

[0038] Fig.19 A wireless device according to an embodiment of the present disclosure is shown.

[0039] Fig. 20 A signal processing circuit for transmitting a signal according to an embodiment of the present disclosure is shown.

[0040] Fig.21 A wireless device according to an embodiment of the present disclosure is shown.

[0041] Fig. 22 A handheld device according to an embodiment of the present disclosure is shown.

[0042] Fig.23 An automobile or autonomous vehicle according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0043] In this specification, "A or B" may mean "only A", "only B", or "both A and B". In other words, in this specification, "A or B" may be interpreted as "A and / or B". For example, in this specification, "A, B or C" may mean "only A", "only B", "only C", or "any combination of A, B, C".

[0044] A slash ( / ) or a comma used in this specification 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".

[0045] In the present specification, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, in the present specification, 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".

[0046] In addition, in the present specification, "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".

[0047] In addition, brackets used in this specification may mean "for example". Specifically, when 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 this specification is not limited to "PDCCH", and "PDDCH" may be proposed as an example of "control information". Specifically, when indicated as "control information (ie, PDCCH)", this may also mean that "PDCCH" is proposed as an example of "control information".

[0048] The technical features described in each of the drawings in this specification may be implemented separately or simultaneously.

[0049] 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 Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE uses OFDMA in the downlink and SC-FDMA in the uplink. LTE-Advanced (LTE-A) is an evolution of LTE.

[0050] 5G NR is a subsequent technology of LTE-A corresponding to a new mobile communication system with high performance, low latency, high availability, etc. 5G NR can use all available spectrum resources including low frequency bands less than 1 GHz, intermediate frequency bands from 1 GHz to 10 GHz, and high frequency (millimeter wave) above 24 GHz.

[0051] For the sake of clarity, the following description will mainly focus on LTE-A or 5G NR. However, the technical features of the embodiments of the present disclosure will not be limited thereto.

[0052] 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.

[0053] 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 to 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 as 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 as other terms such as a base transceiver system (BTS), an access point (AP), etc.

[0054] Figure 2 The embodiment of the present invention illustrates a case where only gNB is included. The BSs 20 may be connected to each other via an Xn interface. The BSs 20 may be connected to each other via a fifth generation (5G) core network (5GC) and an NG interface. More specifically, the 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.

[0055] Figure 3 The functional division between NG-RAN and 5GC according to an embodiment of the present disclosure is shown.

[0056] Reference Figure 3 , 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 provision, dynamic resource allocation, etc. AMF can provide functions such as non-access stratum (NAS) security, idle state mobility processing, etc. UPF can provide functions such as mobility anchoring, protocol data unit (PDU) processing, etc. Session management function (SMF) can provide functions such as user equipment (UE) Internet protocol (IP) address allocation, PDU session control, etc.

[0057] The radio interface protocol layer between the UE and the network can be classified into the first layer (L1), the second layer (L2), and the third layer (L3) based on the lower three layers of the open system interconnection (OSI) model known in the communication system. Here, the physical (PHY) layer belonging to the first layer provides an information transmission service using a physical channel, and the radio resource control (RRC) layer located at the third layer controls radio resources between the UE and the network. To this end, the RRC layer exchanges RRC messages between the UE and the BS layer.

[0058] Figure 4 A radio protocol architecture according to an embodiment of the present disclosure is shown. Figure 4The 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.

[0059] Reference Figure 4 , the physical layer provides information transfer services to the upper layer through the physical channel. The physical layer is connected to the medium access control (MAC) layer, which is the upper layer of the physical layer, through the transport channel. Data is transferred between the MAC layer and the physical layer through the transport channel. The transport channel is classified according to how the data is transmitted through the radio interface and what characteristics of the data it transmits.

[0060] Data is transmitted through a physical channel between different PHY layers (ie, a PHY layer of a transmitter and a PHY layer of a receiver). The physical channel may be modulated using an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and uses time and frequency as radio resources.

[0061] The MAC layer provides services to the Radio Link Control (RLC) layer via logical channels, and the RLC layer is a higher layer of the MAC layer. The MAC layer provides a function of mapping multiple logical channels to multiple transport channels. The MAC layer also provides a function of logical channel multiplexing by mapping multiple logical channels to a single transport channel. The MAC layer provides data transmission services through logical channels.

[0062] The RLC layer performs concatenation, segmentation, and reassembly of Radio Link Control Service Data Units (RLC SDUs). In order to ensure different Quality of Service (QoS) required by Radio Bearers (RBs), the RLC layer provides three types of operation modes, namely, Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provides error correction through Automatic Repeat Request (ARQ).

[0063] The Radio Resource Control (RRC) layer is defined only in the control plane. And, the RRC layer performs functions of controlling physical channels, transport channels, and logical channels related to configuration, reconfiguration, and release of radio bearers. RB refers to a logical path provided by the first layer (i.e., the PHY layer) and the second layer (i.e., the MAC layer, the RLC layer, and the Packet Data Convergence Protocol (PDCP) layer) to transmit data between the UE and the network.

[0064] The functions of the Packet Data Convergence Protocol (PDCP) in the user plane include transmission, header compression and encryption of user data. The functions of the Packet Data Convergence Protocol (PDCP) in the control plane include transmission and encryption / integrity protection of control plane data.

[0065] 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.

[0066] Configuration of RB refers to the process for specifying radio protocol layers and channel attributes to provide a specific service and for determining corresponding detailed parameters and operation methods. RB can then be classified into two types, namely, signaling radio bearer (SRB) and data radio bearer (DRB). SRB is used as a path for transmitting RRC messages in the control plane, and DRB is used as a path for transmitting user data in the user plane.

[0067] When the 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 can be in the RRC idle (RRC_IDLE) state. In the case of NR, the RRC inactive (RRC_INACTIVE) state is additionally defined, and the UE in the RRC_INACTIVE state can maintain the connection with the core network and release its connection with the BS.

[0068] The downlink transmission channels for transmitting (or transferring) data from the network to the UE include a broadcast channel (BCH) for transmitting system information and a downlink shared channel (SCH) for transmitting other user services or control messages. The services or control messages of downlink multicast or broadcast services can be transmitted via the downlink SCH or can be transmitted via a separate downlink multicast channel (MCH). In addition, the uplink transmission channels for transmitting (or transferring) data from the UE to the network include a random access channel (RACH) for transmitting initial control messages and an uplink shared channel (SCH) for transmitting other user services or control messages.

[0069] 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.

[0070] A physical channel is configured by multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. A subframe is configured by multiple OFDM symbols in the time domain. A resource block is configured by multiple subcarriers and multiple OFDM symbols in a resource allocation unit. In addition, each subframe may use a specific subcarrier of a specific OFDM symbol (e.g., the first OFDM symbol) of a corresponding subframe of a physical downlink control channel (PDCCH), i.e., an L1 / L2 control channel. A transmission time interval (TTI) refers to the unit time of subframe transmission.

[0071] 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.

[0072] 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).

[0073] When a normal CP is used, each time slot may include 14 symbols. When an extended CP is used, each time slot may 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).

[0074] Table 1 below shows the number of time slots (N) of each symbol according to the SCS setting (μ) when the 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 ).

[0075] [Table 1]

[0076] <![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

[0077] 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.

[0078] [Table 2]

[0079] <![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

[0080] In the NR system, OFDM (A) parameter sets (e.g., SCS, CP length, etc.) between multiple cells integrated into one UE can be configured differently. Therefore, the (absolute time) duration (or interval) of time resources (e.g., subframes, time slots, or TTIs) (collectively referred to as time units (TUs) for simplicity) consisting of the same number of symbols can be configured differently in the integrated cells. In NR, multiple parameter sets or SCSs for supporting various 5G services can be supported. For example, when the SCS is 15kHz, a wide range of traditional cellular bands can be supported, and when the SCS is 30kHz / 60kHz, dense cities, lower latency, and wider carrier bandwidths can be supported. When the SCS is 60kHz or higher, in order to overcome phase noise, bandwidths greater than 24.25GHz can be used.

[0081] The NR frequency band may 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 may 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 frequency bands. Unlicensed frequency bands may be used for various purposes, for example, unlicensed frequency 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 2 shows the structure of the time slot of the NR frame according to the embodiment of the present disclosure. Figure 6, a time slot includes multiple symbols in the time domain. For example, in the case of normal CP, one time slot may include 14 symbols. For example, in the case of extended CP, one time slot may include 12 symbols. Alternatively, in the case of normal CP, one time slot may include 7 symbols. However, in the case of extended CP, one time slot may include 6 symbols.

[0088] 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 an activated BWP. 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.

[0089] In addition, the radio interface between a UE and another UE or the radio interface 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.

[0090] Hereinafter, the bandwidth part (BWP) and the carrier will be described in detail.

[0091] 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.

[0092] When bandwidth adaptation (BA) is used, the reception bandwidth and transmission bandwidth of the UE are not required to be as large as the bandwidth of the cell, and the reception bandwidth and transmission bandwidth of the BS can be adjusted. For example, the network / BS can notify the UE of the bandwidth adjustment. For example, the UE can receive information / configuration for bandwidth adjustment from the network / BS. In this case, the UE can perform bandwidth adjustment based on the received information / configuration. For example, bandwidth adjustment may include a reduction / expansion of bandwidth, a change in the position of bandwidth, or a change in the subcarrier spacing of bandwidth.

[0093] For example, the bandwidth may be reduced during a duration with little activity in order to save power. For example, the location of the bandwidth may be moved in the frequency domain. For example, the location of the bandwidth may be moved in the frequency domain in order to enhance scheduling flexibility. For example, the subcarrier spacing of the bandwidth may be changed. For example, the subcarrier spacing of the bandwidth may be changed in order to authorize different services. A subset of the total cell bandwidth of a cell may be referred to as a bandwidth part (BWP). BA may be performed when the base station / network configures a BWP for a UE and when the base station / network notifies the UE of the BWP that is currently activated among the BWPs.

[0094] 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 a DL BWP other than an activated DL BWP within a primary cell (PCell). For example, the UE cannot receive PDCCH, PDSCH, or CSI-RS (except RRM) from outside the activated DL BWP. For example, the UE cannot trigger a channel state information (CSI) report for an unactivated DL BWP. For example, the UE cannot transmit PUCCH or PUSCH from outside the unactivated DL BWP. For example, in the case of a downlink, the initial BWP may be given as a continuous RB set for an RMSI CORESET (configured by PBCH). For example, in the case of an uplink, the initial BWP may be given by the SIB for a random access procedure. For example, a default BWP may be configured by a higher layer. For example, the initial value of the default BWP may be the initial DL BWP. In order to save energy, if the UE fails to detect DCI within a predetermined time period, the UE may switch the UE's activated BWP to a default BWP.

[0095] In addition, a BWP may be defined for SL. The same SL BWP may be used for transmission and reception. For example, a transmitting UE may transmit a SL channel or a SL signal within a specific BWP, and a receiving UE may receive a SL channel or a SL signal within the same specific BWP. In a licensed carrier, the SL BWP may be defined separately from the Uu BWP, and the SL BWP may have configuration signaling separate from the Uu BWP. For example, the UE may receive a configuration for the SL BWP from the base station / network. The SL BWP may be (pre-)configured for out-of-coverage NR V2X UEs and RRC_IDLE UEs. For UEs operating in RRC_CONNECTED mode, at least one SL BWP may be activated within the carrier.

[0096] 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 implementation manner, the number of BWPs is 3.

[0097] Reference Figure 7 , a common resource block (CRB) may be a carrier resource block numbered from one end of a carrier frequency band to the other end thereof. Additionally, a PRB may be a resource block numbered within each BWP. Point A may indicate a common reference point of a resource block grid.

[0098] 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 may be an external reference point of the PRBs of the carrier, and subcarrier 0 of all parameter sets (e.g., all parameter sets supported by the network on the corresponding carrier) are aligned in point A. For example, the offset may be the PRB distance between the lowest subcarrier within a given parameter set and point A. For example, the bandwidth may be the number of PRBs within a given parameter set.

[0099] Hereinafter, V2X or SL communication will be described.

[0100] 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 a user plane protocol stack, and Figure 8 (b) in FIG. 5 shows the control plane protocol stack.

[0101] Next, the side link synchronization signal (SLSS) and the synchronization information will be described in detail.

[0102] The SLSS may include a primary side link synchronization signal (PSSS) and a secondary side link synchronization signal (SSSS) as SL specific sequences. The PSSS may be referred to as a side link primary synchronization signal (S-PSS), and the SSSS may be referred to as a side 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 a synchronization signal ID.

[0103] The physical sidelink broadcast channel (PSBCH) can be a (broadcast) channel for transmitting default (system) information, which must be known by the UE first 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 24-bit CRC.

[0104] S-PSS, S-SSS, and PSBCH may be included in a block format that supports periodic transmission (e.g., SL synchronization signal (SS) / PSBCH block, hereinafter, sidelink synchronization signal block (S-SSB)). The S-SSB may have the same parameter set (i.e., SCS and CP length) as the physical sidelink control channel (PSCCH) / physical sidelink shared channel (PSSCH) in the carrier, and the transmission bandwidth may exist within a (pre-) configured sidelink (SL) BWP. For example, the S-SSB may have a bandwidth of 11 resource blocks (SBs). For example, the PSBCH may exist across 11 RBs. In addition, the frequency position of the S-SSB may be (pre-) configured. Therefore, the UE does not have to perform hypothesis detection at the frequency to discover the S-SSB in the carrier.

[0105] Fig. 9 A UE performing V2X or SL communication according to an embodiment of the present disclosure is shown. Fig. 9 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0106] Reference Fig. 9 In V2X or SL communication, the term "UE" may generally refer to a user's UE. However, if a network device such as a BS transmits / receives a signal according to a communication scheme between UEs, the BS may also be regarded as a type of UE. For example, UE 1 may be a first device 100, and UE 2 may be a second device 200.

[0107] For example, UE 1 may select a resource unit corresponding to a specific resource in a resource pool meaning a set of resource series. In addition, UE 1 may transmit an SL signal by using the resource unit. For example, a resource pool in which UE 1 can transmit a signal may be configured to UE 2 as a receiving UE, and a signal of UE 1 may be detected in the resource pool.

[0108] Herein, if UE 1 is within the connection range of the BS, the BS may inform the resource pool to UE 1. Otherwise, if UE 1 is out of the connection range of the BS, another UE may inform UE 1 of the resource pool, or UE 1 may use a pre-configured resource pool.

[0109] 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 signal transmission.

[0110] Hereinafter, resource allocation in SL will be described.

[0111] Fig.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. Fig.10 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure. In various embodiments of the present disclosure, the transmission mode may be referred to as a mode or a resource allocation mode. Hereinafter, for ease of explanation, in LTE, the transmission mode may be referred to as an LTE transmission mode. In NR, the transmission mode may be referred to as an NR resource allocation mode.

[0112] For example, Fig.10 (a) in FIG. 1 shows UE operations related to LTE transmission mode 1 or LTE transmission mode 3. Alternatively, for example, Fig.10 (a) in FIG. 1 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.

[0113] For example, Fig.10 (b) in FIG. 4 shows UE operations related to LTE transmission mode 2 or LTE transmission mode 4. Alternatively, for example, Fig.10 (b) in FIG. 1 shows UE operation related to NR resource allocation mode 2.

[0114] Reference Fig.10 (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 through PDCCH (more specifically, downlink control information (DCI)), and UE 1 may perform V2X or SL communication for UE 2 according to the resource scheduling. For example, UE 1 may transmit sidelink control information (SCI) to UE 2 through a physical sidelink control channel (PSCCH), and thereafter, transmit data based on the SCI to UE 2 through a physical sidelink shared channel (PSSCH).

[0115] Reference Fig.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 may be a resource pool. For example, the UE may autonomously select or schedule resources for SL transmission. For example, the UE may perform SL communication by autonomously selecting resources in the configured resource pool. For example, the UE may autonomously select resources within a selection window by performing a sensing and resource (re)selection process. For example, sensing may be performed in units of subchannels. In addition, UE 1, which has autonomously selected resources within the resource pool, may transmit SCI to UE2 via PSCCH, and thereafter may transmit data based on the SCI to UE2 via PSSCH.

[0116] Fig.11 Three playback types according to an embodiment of the present disclosure are shown. Fig.11 The embodiments of can be combined with various embodiments of the present disclosure. Specifically, Fig.11 (a) shows a broadcast type SL communication, Fig.11 (b) shows unicast type SL communication, and Fig.11 (c) shows a multicast type SL communication. In the case of a unicast type SL communication, the UE can perform a one-to-one communication with another UE. In the case of a multicast type 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 with SL multicast communication, SL one-to-many communication, etc.

[0117] At the same time, in the next generation communication system, various use cases can be supported. For example, a service for communication such as autonomous vehicles, smart cars, or connected cars can be considered. For this service, each vehicle can transmit and receive information as a communication terminal, select resources for communication with or without the help of a base station according to the situation, and send and receive messages between terminals.

[0118] Meanwhile, in the case of a side link in the next communication system, at least two side link modes may be defined. For example, in the case of NR side link mode 1, the base station may schedule side link resources to be used by the UE for side link transmission. For example, in the case of NR side link mode 2, the UE may determine the side link transmission resources within the side link resources configured by the base station / network or the pre-configured side link resources. The configured side link resources or the pre-configured side link resources may be resources / resource pools.

[0119] For example, when there is uplink data to be transmitted by the UE, the scheduling request for uplink communication of the UE may be a signal for the UE to request scheduling from the base station. In addition, for example, when there is sidelink data to be transmitted by the UE, the scheduling request for performing NR sidelink mode 1 communication of the UE may be a signal for the UE to request scheduling from the base station. For example, a base station receiving a scheduling request for uplink communication transmitted by the UE may transmit an uplink (UL) grant including uplink scheduling information to the UE via PDCCH. A base station receiving a scheduling request for performing NR sidelink mode 1 communication transmitted by the UE may transmit a sidelink resource including sidelink scheduling information to the UE via PDCCH. For example, a UE receiving an uplink grant from a base station may transmit a PUSCH using an uplink grant. A UE receiving a sidelink resource from a base station may perform sidelink communication using the sidelink resource. At this time, when a buffer status report (BSR) for uplink communication or a buffer status report for transmission of NR sidelink mode 1 communication is triggered, the base station may transmit an uplink grant for transmitting each buffer status report to the UE. A UE that receives an uplink grant for transmitting a buffer status report may transmit the buffer status report using the uplink grant.

[0120] Hereinafter, a method for a sidelink UE to perform retransmission and a device supporting the method will be described.

[0121] For example, a transmitting UE performing NR sidelink mode 1 communication may transmit data to a receiving UE. The transmitting UE may receive sidelink HARQ feedback information (e.g., ACK, NACK, etc.) for the data from the receiving UE. The transmitting UE may determine whether to retransmit based on the received sidelink HARQ feedback information. When the transmitting UE receives a NACK from the receiving UE, the transmitting UE may request resource allocation for retransmission from the base station through a scheduling request and / or a buffer status report transmission. For the above purpose, the scheduling request and buffer status report may be preconfigured.

[0122] According to an embodiment of the present disclosure, the base station may allocate initial resources (IN_RSC) and N retransmission resources (RE_RSC) to a transmission UE performing NR side link mode 1 communication. Resource allocation may be performed by predefined signaling. In this case, the transmission UE may perform a data transmission operation or a retransmission operation according to various embodiments of the present disclosure. As an example, even when the sum of the number of initial transmission resources and the number of retransmission resources allocated to the transmission UE by the base station is N, the embodiment may be extended.

[0123] Fig.12 A process in which a UE performs sidelink retransmission based on retransmission resources according to an embodiment of the present disclosure is shown. Fig.12The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0124] refer to Fig.12 , in step S1210, IN_RSC and RE_RSC may be allocated from the base station to the first UE. For example, the first UE may receive information related to initial transmission resources and information related to retransmission resources from the base station. For example, the first UE may be a transmitting UE that performs NR sidelink mode 1 communication, and the second UE may be a receiving UE that performs sidelink communication with the first UE. For example, when sidelink data to be transmitted from the first UE to the second UE is generated and a buffer status report (BSR) is triggered for the first UE, the first UE may transmit a scheduling request for data transmission to the base station. For example, the second UE may be a receiving UE that receives sidelink data from other UEs. Subsequently, for example, resources for the BSR may be allocated from the base station to the first UE, the first UE may transmit the BSR from the base station, and resources for data transmission may be allocated from the base station to the first UE. For example, resources for data transmission may include IN_RSC and RE_RSC.

[0125] In step S1220, the first UE may transmit sidelink data to the second UE based on IN_RSC. For example, the first UE may transmit sidelink data to the second UE based on information related to the initial transmission resource. For example, the sidelink data may be included in the sidelink information. For example, the sidelink information may include at least one of a sidelink message, a sidelink packet, a sidelink service, a sidelink data, a sidelink control information and / or a sidelink transport block (TB).

[0126] In step S1230, the first UE may receive NACK information related to the sidelink data from the second UE. For example, the first UE may receive HARQ feedback information related to the sidelink data from the second UE. For example, the HARQ feedback information may include HARQ ACK or HARQ NACK.

[0127] In step S1240, the first UE may transmit sidelink data to the second UE based on RE_RSC. For example, the first UE does not transmit a scheduling request and / or a buffer status report to the base station, and the first UE may transmit sidelink data to the second UE based on RE_RSC.

[0128] For example, the first UE does not transmit a scheduling request and / or a buffer status report to the base station, and the first UE may use N RE_RSCs for retransmission purposes. For example, it may be applicable when the first UE receives a NACK from the receiving UE. In this document, for example, the N value may be a value reported by the first UE to the base station through predefined signaling (option #1) based on at least one of the sidelink channel state information, interference level information, congestion level information, sidelink reference signal received power (RSRP), sidelink reference signal received quality (RSRQ) and / or sidelink received signal strength indicator (RSSI). For example, the predefined signaling may include signaling through PUCCH / PUSCH, signaling through SR / BSR, signaling through MAC / RRC messages, and signaling based on UE auxiliary information.

[0129] Alternatively, for example, the N value is a value derived / calculated by the base station based on at least one of the sidelink RSRP, sidelink RSRQ, sidelink RSSI and / or sidelink channel state information reported from the first UE (option #2).

[0130] For example, an operation may be defined in which the first UE reports to the base station a maximum number of retransmissions (MAX_RETXNUM) associated with the sidelink communication. For example, the value of MAX_RETXNUM may be the maximum possible or maximum required number of retransmissions. In this context, the sum of the number of transmissions including the initial transmission, N retransmissions, and N subsequent retransmissions must be less than or equal to the value of MAX_RETXNUM+1, and it must satisfy the latency budget requirement associated with the sidelink communication.

[0131] For example, the maximum N value that the base station can configure or the UE can request or the maximum value of MAX_RETXNUM can be configured or limited differently according to the service type, service priority, service requirements (e.g., waiting time, reliability), congestion level and / or interference level of the resource pool. For example, the minimum N value that the base station can configure or the UE can request or the minimum value of MAX_RETXNUM can be configured or limited differently according to the service type, service priority, service requirements (e.g., waiting time, reliability), congestion level and / or interference level of the resource pool.

[0132] For example, in option #1, the N value reported by the first UE to the base station can be defined as the number of transmissions that can meet the target success probability of the sidelink service or the average number of transmission attempts until the transmission is successful. For example, the N value can be the number of transmissions that can meet the target success probability of the sidelink service. For example, the N value can be the average number of transmission attempts until the transmission is successful that can meet the target success probability of the sidelink service. For example, if the N value defining the number of transmissions that can meet the target success probability of the sidelink service is 4, it may mean that a target reliability of 99% can be achieved when transmitting 4 times.

[0133] Fig.13 The process of UE stopping sidelink retransmission according to an embodiment of the present disclosure is shown. Fig.13 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0134] refer to Fig.13 In step S1310, IN_RSC and RE_RSC may be allocated from the base station to the first UE. For example, the first UE may receive information related to initial transmission resources and information related to retransmission resources from the base station.

[0135] In step S1320, the first UE may transmit sidelink data to the second UE based on IN_RSC. For example, the first UE may transmit sidelink data to the second UE based on information related to the initial transmission resource. In step S1330, the first UE may receive NACK information related to the sidelink data from the second UE. In step S1340, the first UE may transmit sidelink data to the second UE based on RE_RSC. In step S1350, the first UE may receive ACK information from the second UE. For example, the ACK information may be ACK information received after the first UE performs retransmission using a number of RE_RSCs less than N.

[0136] In step S1360, the first UE may transmit a release request message to the base station. For example, the first UE may transmit a release request message to the base station based on the ACK information received from the second UE. For example, the first UE performs retransmission using a number of RE_RSCs less than N, and the first UE may transmit a release request message to the base station based on receiving an ACK from the second UE. For example, the release request message may be a message for releasing the retransmission process of the remaining RE_RSC. For example, the remaining RE_RSC may be a value obtained by subtracting the number of retransmissions performed for the second UE before the first UE receives the ACK information from the RE_RSC allocated to the first UE. For example, the release request message may be transmitted by predefined signaling. That is, the first UE performs retransmission using a number of RE_RSCs less than N, and the first UE may transmit a release request message to the base station by predefined signaling based on receiving an ACK from the second UE. For example, the first UE performs retransmission using a number of RE_RSCs less than N, and the first UE may omit or not retransmit the retransmission operation of the remaining RE_RSC based on receiving an ACK from the second UE.

[0137] Fig.14 It shows a process in which the UE continues to perform sidelink retransmission according to an embodiment of the present disclosure. Fig.14 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0138] refer to Fig.14 In step S1410, IN_RSC and RE_RSC may be allocated from the base station to the first UE. For example, the first UE may receive information related to initial transmission resources and information related to retransmission resources from the base station.

[0139] In step S1420, the first UE may transmit sidelink data to the second UE based on IN_RSC. For example, the first UE may transmit sidelink data to the second UE based on information related to the initial transmission resource. In step S1430, the first UE may receive NACK information related to the sidelink data from the second UE. In step S1440, the first UE may transmit sidelink data to the second UE based on RE_RSC. In step S1450, the first UE may receive NACK information from the second UE. For example, the NACK information may be NACK information received after the first UE performs retransmission using N RE_RSCs.

[0140] In step S1460, the first UE may determine whether to transmit a scheduling request to the base station based on a predefined condition. In step S1470, the first UE may transmit a scheduling request to the base station. For example, if the first UE satisfies the predefined condition, the first UE may request additional retransmission resource allocation through a scheduling request and / or a buffer status report transmission. For example, if the waiting time budget is greater than the delay required to request and allocate retransmission resources through a scheduling request and / or a buffer status report transmission, the predefined condition is met. For example, if the remaining waiting time budget associated with the sidelink data / packet / service is greater than the delay required to request and allocate retransmission resources through a scheduling request and / or a buffer status report transmission, the predefined condition is met. For example, if the remaining waiting time budget associated with the sidelink data / packet / service is greater than the pre-configured maximum delay required to request and allocate retransmission resources through a scheduling request and / or a buffer status report transmission, the predefined condition is met. For example, the remaining waiting time budget associated with the sidelink data / packet / service can be obtained by excluding the time between the time when the first UE performs initial sidelink data transmission and the time when NACK information is received from the second UE from the total waiting time budget associated with the sidelink data transmission of the first UE. For example, the first UE can transmit a scheduling request to the base station based on the remaining waiting time budget associated with the sidelink data being equal to or greater than a preconfigured delay time. For example, the first UE can transmit a scheduling request to the base station based on the remaining waiting time budget associated with the sidelink data being greater than the preconfigured delay time. For example, the preconfigured delay time may include the delay time required to request and allocate retransmission resources through a scheduling request and / or buffer status report transmission for the sidelink data.

[0141] For example, if the predefined condition is not met, the first UE may stop or omit the retransmission operation. For example, if the predefined condition is not met, the first UE may perform the retransmission operation based on NR sidelink mode 2. Alternatively, for example, based on receiving NACK information from the second UE, the first UE may perform the retransmission operation based on NR sidelink mode 2.

[0142] Alternatively, for example, based on receiving NACK information from the second UE, it can be assumed that the HARQ operation in the MAC layer of the first UE is terminated, and the ARQ operation in the RLC layer is performed / started. Alternatively, based on receiving NACK information from the second UE, the HARQ operation in the MAC layer of the first UE can be terminated, and the ARQ operation in the RLC layer can be performed / started. For example, based on receiving NACK information from the second UE, it can be assumed that the HARQ operation related to sidelink data transmission in the MAC layer of the first UE is terminated, and the ARQ operation in the RLC layer is performed / started. Alternatively, based on receiving NACK information from the second UE, the HARQ operation related to sidelink data transmission in the MAC layer of the first UE can be terminated, and the ARQ operation in the RLC layer can be performed / started.

[0143] According to an embodiment of the present disclosure, the above-mentioned retransmission operation based on the NR side link mode 2 of the first UE can be performed or allowed only when all or part of the following conditions are met. For example, if all or part of the following conditions are not met, the retransmission operation based on the NR side link mode 2 of the first UE can be omitted, not performed or not allowed. In this article, for example, the thresholds related to the following conditions can be configured or defined differently based on at least one of the service type, service priority, service requirements (e.g., waiting time, reliability), congestion level of the resource pool and / or interference level.

[0144] For example, if the channel busy rate (CBR) measurement value is less than a preconfigured threshold, the first UE can perform a retransmission operation based on NR sidelink mode 2. For example, if the CBR measurement value associated with the sidelink data transmission is less than a preconfigured threshold, the first UE can allocate resources associated with the sidelink transmission to the second UE, and the first UE can retransmit the sidelink data to the second UE through the allocated resources.

[0145] For example, when the remaining channel occupancy (CR) measurement value associated with NR sidelink mode 2 is greater than a preconfigured threshold, the first UE may perform a retransmission operation based on NR sidelink mode 2. For example, if the remaining CR measurement value associated with sidelink data transmission is greater than a preconfigured threshold, the first UE may allocate resources associated with sidelink transmission to the second UE, and the first UE may retransmit the sidelink data to the second UE through the allocated resources.

[0146] For example, when the sidelink RSRP measurement value is greater than a preconfigured threshold, the first UE may perform a retransmission operation based on NR sidelink mode 2. For example, if the RSRP measurement value associated with the sidelink data is greater than a preconfigured threshold, the first UE may allocate resources associated with the sidelink transmission to the second UE, and the first UE may retransmit the sidelink data to the second UE through the allocated resources.

[0147] For example, when the sidelink RSRQ measurement value is greater than a preconfigured threshold, the first UE may perform a retransmission operation based on NR sidelink mode 2. For example, if the RSRQ measurement value associated with the sidelink data is greater than a preconfigured threshold, the first UE may allocate resources associated with the sidelink transmission to the second UE, and the first UE may retransmit the sidelink data to the second UE through the allocated resources.

[0148] For example, when the sidelink CSI measurement value or the sidelink CSI report value is greater than a preconfigured threshold, the first UE may perform a retransmission operation based on NR sidelink mode 2. For example, if the CSI measurement value associated with the sidelink data or the CSI report value associated with the sidelink data is greater than a preconfigured threshold, the first UE may allocate resources associated with the sidelink transmission to the second UE, and the first UE may retransmit the sidelink data to the second UE through the allocated resources.

[0149] For example, when the sidelink RSSI measurement value is less than a preconfigured threshold, the first UE may perform a retransmission operation based on NR sidelink mode 2. For example, if the RSSI measurement value associated with the sidelink data is less than a preconfigured threshold, the first UE may allocate resources associated with the sidelink transmission to the second UE, and the first UE may retransmit the sidelink data to the second UE through the allocated resources.

[0150] For example, when the sidelink interference measurement value is less than a preconfigured threshold, the first UE may perform a retransmission operation based on NR sidelink mode 2. For example, if the interference measurement value associated with the sidelink data is less than a preconfigured threshold, the first UE may allocate resources associated with the sidelink transmission to the second UE, and the first UE may retransmit the sidelink data to the second UE through the allocated resources.

[0151] According to an embodiment of the present disclosure, the transmission power parameters / values ​​in INI_RSC and N RE_RSCs (e.g., PO related to OLPC (open-loop power control), alpha related to OLPC, maximum allowable power, or minimum allowable power value) may be configured differently from the transmission power parameters / values ​​in the retransmission resources after INI_RSC and RE_RSC. For example, in order to improve the data transmission success rate during the initial transmission and N retransmissions, the transmission power parameters / values ​​in INI_RSC and N RE_RSCs may be configured to be relatively higher than the transmission power parameters / values ​​in the retransmission resources after INI_RSC and RE_RSC. For example, the transmission scheme in INI_RSC and N RE_RSCs (e.g., transmission diversity / closed-loop MIMO technology, beamforming, etc.) may be configured differently from the transmission scheme in the retransmission resources after INI_RSC and RE_RSC.

[0152] According to an embodiment of the present disclosure, for up to N retransmissions, the first UE may request the base station to allocate retransmission resources through a scheduling request and / or a buffer status report transmission, and for retransmissions after N times, the first UE may request the base station to allocate retransmission resources through a scheduling request and / or a buffer status report transmission. Thereafter, the base station may additionally allocate K retransmission resources, and the first UE does not transmit a scheduling request and / or a buffer status report, and the first UE may use K retransmission resources to perform retransmission. For example, the maximum value of N, the minimum value of N, or the value of K may be configured differently according to the service type, the priority of the service, the service requirements (e.g., waiting time, reliability), the congestion level and / or interference level of the resource pool, etc. For example, K retransmission resources may be configured within the remaining waiting time budget associated with the sidelink service.

[0153] According to an embodiment of the present disclosure, when a first UE performs initial transmission and, in the case of receiving NACK from a second UE, the first UE needs to perform serving cell switching before performing retransmission, the first UE may perform retransmission based on NR sidelink mode 2.

[0154] In the present disclosure, retransmission based on NR sidelink mode 2 may refer to a retransmission operation associated with a specific transport block (TB) through a resource after the transmitting UE reserves / selects a resource with relatively low interference measured through a sensing operation (the UE operates independently in a resource pool).

[0155] Hereinafter, according to an embodiment of the present disclosure, a method for performing sidelink communication by a UE that simultaneously receives sidelink mode 1 operation and sidelink mode 2 operation and an apparatus supporting the method will be described.

[0156] According to an embodiment of the present disclosure, when a UE is configured to operate in sidelink (SL) mode 1 / 2 at the same time, for efficient operation of SL mode 1 / 2 resources and / or efficient sharing of SL mode 1 / 2 resources for packet transmission associated with a specific service, it can be performed or defined based on all or part of the embodiments proposed below. For example, sidelink mode 1 operation may refer to a situation where a base station directly schedules resources related to the sidelink transmission of the UE through predefined signaling (e.g., DCI). For example, sidelink mode 2 operation may refer to a situation where a UE independently selects resources related to the sidelink transmission from a preconfigured resource pool. In this document, for example, a preconfigured resource pool may be a resource pool preconfigured from a base station or a network. For example, in the present disclosure, a UE configured to operate in sidelink mode 1 / 2 (hereinafter, M1 / 2_UE) may refer to a UE configured by a base station or a network to operate in sidelink mode 1 and sidelink mode 2 at the same time. For example, simultaneous configuration of sidelink mode 1 / 2 operation may be performed / specified for the same resource pool and / or carrier.

[0157] Fig.15 A process for performing sidelink communication by a UE configured with both sidelink resource allocation mode 1 and sidelink resource allocation mode 2 according to an embodiment of the present disclosure is shown. Fig.15 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0158] refer to Fig.15 In step S1510, the M1 / 2_UE may receive information related to the sidelink mode 1 from the base station. For example, the M1 / 2_UE may receive information related to the sidelink mode 1 from the base station before being allocated resources from the base station in the sidelink mode 1. For example, the information related to the sidelink mode 1 may include at least one of the following: time interval information for maintaining the sidelink mode 1 resources, timer information for maintaining the sidelink mode 1 resources, information about the number of sidelink mode 1 resources (e.g., information about how many times the sidelink mode 1 resources are maintained / repeated based on a specific period), and priority information of the sidelink mode 1 resources.

[0159] According to an embodiment of the present disclosure, the base station may transmit at least one of the following to the M1 / 2_UE through predefined signaling: time interval information for maintaining side link mode 1 resources, timer information for maintaining side link mode 1 resources, information about the number of side link mode 1 resources (e.g., information about how many times the side link mode 1 resources are maintained / repeated based on a specific period), or priority information of the side link mode 1 resources. For example, the side link mode 1 resources may be included in the side link mode 1, resources scheduled by the base station for the M1 / 2_UE. In this document, for example, the M1 / 2_UE receiving the above information may determine how long the base station maintains the side link mode 1 resources in the time domain. In addition, when performing sensing operations related to side link mode 2 and / or when selecting / reserving resources related to side link mode 2, the M1 / 2_UE may avoid overlapping with the side link mode 1 resources in the time resource domain and / or the frequency resource domain. Alternatively, for example, the M1 / 2_UE assumes that the sidelink mode 1 resources are maintained for an infinite period of time or the number of sidelink mode 1 resources is infinite, and the M1 / 2_UE may perform a sensing operation and / or a sidelink mode 2 resource selection / reservation operation related to sidelink mode 2. For example, the sidelink mode 2 resources may include resources allocated by the M1 / 2_UE to perform sidelink communication with another UE in sidelink mode 2.

[0160] In step S1520, the M1 / 2_UE may determine whether a predefined condition is met, and switch the resource allocation mode according to the determination. For example, the M1 / 2_UE may determine whether a predefined condition is met based on information related to side link mode 1. For example, the M1 / 2_UE may switch the resource allocation mode based on a predefined condition. For example, it may be determined whether the predefined condition is met based on at least one of the priority of packets transmitted through side link mode 1 resources, the priority of packets transmitted through side link mode 2 resources, requirements related to transmission packets on side link mode 1 resources, requirements related to transmission packets on side link mode 2 resources, a waiting time budget for packets transmitted through side link mode 1 resources, or a congestion / interference level on a resource pool. In Fig.15 In the example, it is assumed that M1 / 2_UE switches from sidelink mode 1 to sidelink mode 2 based on predefined conditions.

[0161] In step S1530, the M1 / 2_UE may transmit information related to the sidelink mode 2 to the base station. For example, the M1 / 2_UE may transmit information related to the sidelink mode 2 to the base station based on the switching resource allocation mode. For example, the information related to the sidelink mode 2 may include at least one of the following: priority information related to resources allocated to the sidelink mode 2, priority information of transmission services / packets related to resources allocated to the sidelink mode 2, counter information, reserved period information, subframe offset information, transmission power value information, or resource information related to the preferred sidelink mode 1 from the perspective of the M1 / 2_UE. In step S1540, the M1 / 2_UE may allocate resources in the sidelink mode 2, and the M1 / 2_UE may transmit sidelink data to another UE through the allocated resources.

[0162] According to an embodiment of the present disclosure, M1 / 2_UE may report all or part of the following information to the base station via a predefined signal. For example, as a result of sensing, M1 / 2_UE may transmit at least one of the following to the base station: priority information related to resources allocated to side link mode 2, priority information of transmission services / packets related to resources allocated to side link mode 2, counter information, reserved period information, subframe offset information, transmission power value information, or resource information related to preferred side link mode 1 from the perspective of M1 / 2_UE. For example, the counter information may include counter information selected when reserving / selecting side link mode 2 resources. For example, as a result of M1 / 2_UE sensing resources, resource information related to side link mode 1 that is preferred from the perspective of M1 / 2_UE may be determined based on the time / frequency position of the reserved / selected side link mode 2 resources.

[0163] For example, the base station receiving the sensing result from the M1 / 2_UE may select / reserve resources with relatively small interference as side link mode 1 resources. In addition, for example, the base station may avoid the side link mode 2 resources selected / reserved by the M1 / 2_UE in the time resource domain and / or the frequency resource domain, and may select / reserve the side link mode 1 resources.

[0164] Herein, for example, it may be assumed that the sidelink mode 2 resource reserved / selected by the M1 / 2_UE performing the sensing operation is maintained for a pre-selected counter or number of times. Alternatively, for example, it may be assumed that the sidelink mode 2 resource is maintained for a time interval configured by the base station / network or a configured timer.

[0165] Alternatively, for example, it may be assumed that the sidelink Mode 2 resources are maintained for an infinite period of time. Or, for example, it may be assumed that the number of reserved / selected sidelink Mode 2 resources is infinite for the sidelink Mode 2 resources.

[0166] For example, a probabilistic determination for determining whether to perform reselection / reservation for side link mode 2 resources can be performed in advance. That is, M1 / 2_UE can perform probabilistic determination in advance to determine whether to perform reselection / reservation of side link mode 2 resources. For example, after M1 / 2_UE selects a random value (e.g., a real value) between 0 and 1, if the selected value is greater than a pre-configured threshold, M1 / 2_UE can perform reselection / reservation for side link mode 2 resources. For example, if it is determined to perform reselection / reservation of side link mode 2 resources, it can be assumed that the reserved / selected side link mode 2 resources are maintained by a pre-selected counter or number of times. For example, the pre-selected counter or number of times can be a counter or number of times selected during the reservation / selection of the previous side link mode 2 resources. For example, if it is not determined to perform reselection / reservation of side link mode 2 resources, it can be assumed that the reserved / selected side link mode 2 resources are maintained until it is determined to perform resource reselection / reservation of side link mode 2 resources.

[0167] For example, the M1 / 2_UE may perform / apply a sensing operation on resources among the reserved / selected side link mode 2 resources that are actually not used due to a transmission operation using the side link mode 1 resources. Alternatively, for example, the M1 / 2_UE may not perform / apply a sensing operation on resources among the reserved / selected side link mode 2 resources that are actually not used due to a transmission operation using the side link mode 1 resources.

[0168] According to an embodiment of the present disclosure, when specific conditions are met, M1 / 2_UE may transmit packets of specific service priority and / or packets of specific service requirements transmitted through sidelink mode 1 resources through sidelink mode 2 resources.

[0169] For example, when the M1 / 2_UE performs a sensing operation to reserve / select sidelink mode 2 resources, if the assumed priority is equal to or higher than the priority of the packet transmitted through the sidelink mode 1 resources, the M1 / 2_UE may transmit the packet transmitted through the sidelink mode 1 resources through the sidelink mode 2 resources. For example, when the M1 / 2_UE performs a sensing operation to reserve / select sidelink mode 2 resources, if the assumed service priority is equal to or higher than a preconfigured threshold, the M1 / 2_UE may transmit the packet transmitted through the sidelink mode 1 resources through the sidelink mode 2 resources. For example, if the priority of the resources reserved / selected by the M1 / 2_UE in sidelink mode 2 is equal to or higher than the priority of the packet transmitted through the sidelink mode 1 resources, the M1 / 2_UE may transmit the sidelink information transmitted through the sidelink mode 1 resources to another UE through the sidelink mode 2 resources.

[0170] For example, when the requirements related to transmission packets on the sidelink Mode 2 resources (e.g., waiting time budget, reliability, priority) are the same as or more stringent than the requirements related to transmission packets on the sidelink Mode 1 resources, the M1 / 2_UE may transmit packets transmitted through the sidelink Mode 1 resources through the sidelink Mode 2 resources. For example, when the requirements related to transmission packets on the sidelink Mode 2 resources (e.g., waiting time budget, reliability, priority) are the same as or more stringent than the pre-configured values / levels, the M1 / 2_UE may transmit packets transmitted through the sidelink Mode 1 resources through the sidelink Mode 2 resources.

[0171] For example, if the sidelink mode 2 resources are within the waiting time budget of the packets transmitted through the sidelink mode 1 resources, the M1 / 2_UE may transmit the packets transmitted through the sidelink mode 1 resources through the sidelink mode 2 resources. For example, if there are reserved / selected sidelink mode 2 resources within the remaining waiting time budget of the packets transmitted through the sidelink mode 1 resources, the M1 / 2_UE may transmit the packets transmitted through the sidelink mode 1 resources through the sidelink mode 2 resources.

[0172] For example, when the congestion / interference level on the resource pool is lower than a pre-configured threshold, the M1 / 2_UE may transmit packets that were transmitted via the sidelink Mode 1 resources via the sidelink Mode 2 resources.

[0173] According to an embodiment of the present disclosure, there may not be a reserved / selected side link mode 2 resource that satisfies the above-mentioned specific conditions for transmitting a packet of a specific service priority and / or a packet of a specific service requirement transmitted through a side link mode 1 resource through a side link mode 2 resource. For example, when the M1 / 2_UE cannot transmit a packet of a specific service priority and / or a packet of a specific service requirement transmitted through a side link mode 1 resource through a previously reserved / selected side link mode 2 resource, the M1 / 2_UE may re-reserve / select a side link mode 2 resource. Alternatively, for example, when the M1 / 2_UE cannot transmit a packet of a specific service priority and / or a packet of a specific service requirement transmitted through a side link mode 1 resource through a previously reserved / selected side link mode 2 resource, the M1 / 2_UE may transmit an indicator to the base station to cause a re-reservation / selection of the side link mode 1 resource. In this article, for example, when the M1 / 2_UE performs sensing to re-reserve / select a side link mode 2 resource, the M1 / 2_UE may perform sensing based on the service priority associated with the packet transmitted through the side link mode 1 resource. For example, when the M1 / 2_UE performs sensing to re-reserve / select the side link mode 2 resource, the M1 / 2_UE may perform sensing based on a higher priority of a service priority associated with a packet transmitted through the previously reserved / selected side link mode 2 resource and a service priority associated with a packet transmitted through the side link mode 1 resource. For example, when the M1 / 2_UE performs sensing to re-reserve / select the side link mode 2 resource, the M1 / 2_UE may perform sensing based on a pre-configured service priority. For example, the pre-configured service priority may be a pre-configured service priority from the base station / network.

[0174] In the various embodiments of the present disclosure described above, only retransmissions of packets transmitted through sidelink mode 1 resources may be transmitted through the reserved / selected sidelink mode 2 resources. For example, in order to retransmit packets transmitted through sidelink mode 1 resources through sidelink mode 2 resources, M1 / 2_UE may switch resource allocation modes.

[0175] According to an embodiment of the present disclosure, the side link mode 1 resources scheduled by the base station and the side link mode 2 resources selected / reserved by the UE may not overlap in the frequency resource domain, and all or some may overlap in the time resource domain (for example, when FDM is applied). Or, for example, the side link mode 1 resources scheduled by the base station and the side link mode 2 resources selected / reserved by the UE may overlap in whole or in part in the time resource domain / frequency resource domain. In this case, for example, the M1 / 2_UE may be configured to give priority to the use of the side link mode 1 resources. Or, for example, the M1 / 2_UE may be configured to give priority to the use of the side link mode 2 resources. For example, assuming that the resources on the non-priority mode are invalid, the M1 / 2_UE may omit the packet transmission through the resources in the non-priority mode. Or, for example, the M1 / 2_UE may be configured to give priority to the use of the resources on the pre-signaled mode. For example, the pre-signaled mode may be a pre-signaled resource allocation mode from the base station / network. Or, for example, the M1 / 2_UE may be configured to give priority to the use of the resources on which the packet transmission with a relatively high service priority is performed. For example, the M1 / 2_UE may be configured to preferentially use resources on which packet transmissions with relatively strict service requirements (e.g., low latency budget, high reliability and / or priority) are performed. For example, the M1 / 2_UE may be pre-configured from the base station / network with a service priority or service requirement value associated with resources at a time point when there is no packet transmission.

[0176] Fig.16 A method for a first device 100 to perform sidelink retransmission to a second device 200 according to an embodiment of the present disclosure is shown. Fig.16 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0177] refer to Fig.16 , in step S1610, the first device 100 may perform at least one side link transmission to the second device 200. In step S1620, the first device 100 may receive negative acknowledgement (NACK) information related to the at least one side link transmission from the second device 200. In step S1630, the first device 100 may transmit a scheduling request to the base station based on the remaining waiting time budget related to the at least one side link transmission and the preconfigured delay time threshold. For example, the preconfigured delay time may include a preconfigured delay time threshold. For example, a message for requesting a retransmission resource may include a scheduling request. For example, the first device 100 may determine whether to transmit a message for requesting a retransmission resource based on the remaining waiting time budget related to the at least one side link transmission and the preconfigured delay time threshold.

[0178] For example, the remaining waiting time budget associated with at least one side link transmission may be greater than a preconfigured delay time threshold. For example, the remaining waiting time budget associated with at least one side link transmission may be equal to or greater than a preconfigured delay time threshold. For example, based on the remaining waiting time budget associated with at least one side link transmission being greater than the preconfigured delay time threshold, the first device 100 may transmit a message to the base station for requesting retransmission resources. For example, based on the remaining waiting time budget associated with at least one side link transmission being equal to or greater than the preconfigured delay time threshold, the first device 100 may transmit a message to the base station for requesting retransmission resources. For example, the preconfigured delay time threshold includes the minimum delay time required for requesting retransmission resources and allocating retransmission resources.

[0179] For example, the remaining wait time budget associated with at least one side link transmission may be less than a preconfigured delay time threshold. For example, the remaining wait time budget associated with at least one side link transmission may be equal to or less than a preconfigured delay time threshold. For example, based on the remaining wait time budget associated with at least one side link transmission being less than a preconfigured delay time threshold, at least one side link transmission may be stopped. For example, based on the remaining wait time budget associated with at least one side link transmission being equal to or less than a preconfigured delay time threshold, at least one side link transmission may be stopped. In this case, for example, the first device 100 may determine not to transmit a message for requesting retransmission resources.

[0180] For example, based on the remaining waiting time budget associated with at least one side link transmission being equal to or less than a preconfigured threshold, the first device 100 may perform retransmission based on mode 2. For example, based on the remaining waiting time budget associated with at least one side link transmission being less than a preconfigured threshold, the first device 100 may perform retransmission based on mode 2. For example, based on the resources allocated to the second device 200 by the first device 100 for the side link transmission, retransmission based on mode 2 is performed. For example, based on the CBR measurement value associated with at least one side link transmission being less than a preconfigured threshold, retransmission based on mode 2 may be performed. For example, based on the CBR measurement value associated with at least one side link transmission being equal to or less than a preconfigured threshold, retransmission based on mode 2 may be performed. For example, based on the channel quality value associated with at least one side link transmission being greater than a preconfigured threshold, retransmission based on mode 2 may be performed. For example, based on the channel quality value associated with at least one side link transmission being equal to or greater than a preconfigured threshold, retransmission based on mode 2 may be performed. For example, the channel quality value may include at least one of the following: a reference signal received power (RSRP) associated with at least one side link transmission, a reference signal received quality (RSRQ) associated with at least one side link transmission, a received signal strength indicator (RSSI) associated with at least one side link transmission, a channel state information report value associated with at least one side link transmission, and / or a channel state information measurement value associated with at least one side link transmission. For example, based on the channel quality value associated with at least one side link transmission being less than a preconfigured threshold, retransmission based on mode 2 may be stopped. For example, based on the channel quality value associated with at least one side link transmission being equal to or less than a preconfigured threshold, retransmission based on mode 2 may be stopped. For example, the message for requesting retransmission resources may be any one of a scheduling request or a hybrid automatic repeat request (HARQ) NACK information received from the second device 200.

[0181] For example, the first device 100 may transmit first information related to retransmission to the base station. For example, the first information may include at least one of side link channel state information, interference level information, congestion level information, RSRP information related to side link transmission, RSRQ information related to side link transmission, or RSSI information related to side link transmission. For example, the first device 100 may receive information related to initial transmission resources and second information related to retransmission resources from the base station. For example, the first device 100 may perform at least one side link transmission based on the information related to the initial transmission resources and the second information related to the retransmission resources. For example, the second information may include the number of retransmission resources determined based on the first information.

[0182] Alternatively, for example, the first device 100 may transmit the number of retransmission resources determined based on the first information related to the retransmission to the base station. For example, the first information may include at least one of side link channel state information, interference level information, congestion level information, RSRP information related to the side link transmission, RSRQ information related to the side link transmission, or RSSI information related to the side link transmission. For example, the first device 100 may receive information related to the initial transmission resources and second information related to the retransmission resources from the base station. For example, the first device 100 may perform at least one side link transmission based on the information related to the initial transmission resources and the second information related to the retransmission resources.

[0183] The above embodiments may be applied to various devices to be described below. First, for example, the processor 102 of the first device 100 may control the transceiver 106 to perform at least one sidelink transmission to the second device 200. Furthermore, the processor 102 of the first device 100 may control the transceiver 106 to receive negative acknowledgement (NACK) information related to at least one sidelink transmission from the second device 200. Furthermore, the processor 102 of the first device 100 may control the transceiver 106 to transmit a scheduling request to the base station based on a preconfigured delay time threshold and a remaining waiting time budget related to at least one sidelink transmission.

[0184] According to 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, one or more processors may execute instructions to: perform at least one side link transmission to a second device, receive negative acknowledgment (NACK) information related to the at least one side link transmission from the second device, and determine whether to transmit a message for requesting retransmission resources based on a remaining wait time budget related to at least one side link transmission and a preconfigured delay time threshold.

[0185] According to an embodiment of the present disclosure, a device configured to control a first user equipment (UE) may be provided. For example, the device may include: one or more processors; and one or more memories operably connected to the one or more processors and storing instructions. For example, one or more processors may execute instructions to: perform at least one sidelink transmission to a second UE, receive negative acknowledgment (NACK) information related to at least one sidelink transmission from the second UE, and determine whether to transmit a message for requesting retransmission resources based on a remaining waiting time budget related to at least one sidelink transmission and a preconfigured delay time threshold.

[0186] According to an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be provided. For example, when these instructions are executed, a first device: performs at least one side link transmission to a second device, receives negative acknowledgement (NACK) information related to at least one side link transmission from the second device, and determines whether to transmit a message for requesting retransmission resources based on a remaining waiting time budget related to at least one side link transmission and a preconfigured delay time threshold.

[0187] Fig.17 A method for the first device 100 to stop sidelink retransmission to the second device 200 according to an embodiment of the present disclosure is shown. Fig.17 The embodiments of the present disclosure may be combined with various embodiments of the present disclosure.

[0188] refer to Fig.17 In step S1710, the first device 100 may receive information related to initial transmission resources and information related to retransmission resources from a base station. In step S1720, the first device 100 may perform at least one sidelink transmission based on the information related to the initial transmission resources and the information related to the retransmission resources. In step S1730, after performing at least one sidelink transmission using a number less than the number of retransmission resources included in the information related to the retransmission resources, the first device 100 may receive acknowledgment (ACK) information related to at least one sidelink transmission from the second device 200.

[0189] In step S1740, the first device 100 may transmit a release request message for at least one side link transmission to the base station based on the ACK information. For example, at least one side link transmission related to the remaining retransmission resources based on the ACK information may be stopped. For example, the first device 100 may transmit a release request message for at least one side link transmission related to the remaining retransmission resources to the base station based on the ACK information. For example, the first device 100 may refresh a buffer of the first device 100 for a transmission block related to the remaining retransmission resources based on the ACK information.

[0190] The above-mentioned embodiments can be applied to various devices to be described below. First, for example, the processor 102 of the first device 100 can control the transceiver 106 to receive information related to the initial transmission resource and information related to the retransmission resource from the base station. And, the processor 102 of the first device 100 can control the transceiver 106 to perform at least one side link transmission based on the information related to the initial transmission resource and the information related to the retransmission resource. And, the processor 102 of the first device 100 can control the transceiver 106 to perform at least one side link transmission after performing at least one side link transmission using a number less than the number of retransmission resources included in the information related to the retransmission resource, and receive the acknowledgement (ACK) information related to at least one side link transmission from the second device 200. And, the processor 102 of the first device 100 can control the transceiver 106 to transmit a release request message for at least one side link transmission to the base station based on the ACK information.

[0191] According to 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, one or more processors may execute instructions to: receive information related to initial transmission resources and information related to retransmission resources from a base station, perform at least one side link transmission based on the information related to the initial transmission resources and the information related to the retransmission resources, and after performing at least one side link transmission using a number less than the number of retransmission resources included in the information related to the retransmission resources, receive acknowledgment (ACK) information related to at least one side link transmission from a second device. For example, stop at least one side link transmission related to the remaining retransmission resources based on the ACK information.

[0192] Since the examples of the above-mentioned proposed methods can also be included as one of the implementation methods of the present disclosure, it is obvious that they can be considered as a proposed method. In addition, the above-mentioned proposed methods can be implemented independently, but can also be implemented in the form of a combination (or merger) of some proposed methods. Rules can be defined so that information about whether to apply the proposed method (or information about the rules of the proposed method) is notified to the UE by the base station through a predefined signal (e.g., a physical layer signal or a higher layer signal) or notified to the receiving terminal by the transmitting UE.

[0193] Various embodiments of the present disclosure can be applied not only to vehicle-to-vehicle communication, but also to vehicle-to-pedestrian communication, vehicle-to-base station communication, or vehicle-to-fixed node communication. For example, in communication with a base station, the position and speed of the corresponding receiver can be considered fixed.

[0194] Hereinafter, devices to which various embodiments of the present disclosure can be applied will be described.

[0195] The various descriptions, functions, processes, proposals, methods and / or operational flowcharts 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).

[0196] Hereinafter, a description will be given in more detail 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.

[0197] Fig.18 A communication system (1) according to an embodiment of the present disclosure is shown.

[0198] Reference Fig.18 , 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 head mounted devices (HMD), head up displays (HUD) installed in vehicles, televisions, smart phones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Handheld devices may include smart phones, 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.

[0199] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without going through the BS / network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0200] Wireless communication / connection 150a, 150b or 150c can be established between wireless devices 100a to 100f / BS 200 or BS200 / BS 200. Here, the wireless communication / connection can be established through 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 transmit / receive radio signals to / from each other through wireless communication / connection 150a and 150b. For example, wireless communication / connection 150a and 150b can transmit / receive signals through 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.

[0201] Fig.19 A wireless device according to an embodiment of the present disclosure is shown.

[0202] Reference Fig.19 , the first wireless device (100) and the second wireless device (200) may transmit radio signals via various RATs (e.g., LTE and NR). Herein, {the first wireless device (100) and the second wireless device (200)} may correspond to Fig.18 {wireless device (100x) and BS (200)} and / or {wireless device (100x) and wireless device (100x)}.

[0203] 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 (one or more) processors 102 may control the (one or more) memories 104 and / or the (one or more) transceivers 106, and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operation flows disclosed in this document. For example, the (one or more) processors 102 may process the information in the (one or more) memories 104 to generate first information / signals, and then transmit a radio signal including the first information / signals through the (one or more) transceivers 106. The (one or more) processors 102 may receive a radio signal including a second information / signal through the transceiver 106, and then store the information obtained by processing the second information / signals in the (one or more) memories 104. The (one or more) memories 104 may be connected to the (one or more) processors 102, and may store various information related to the operation of the (one or more) processors 102. For example, (one or more) memories 104 may store software code including commands for executing part or all of the processing controlled by (one or more) processors 102 or for executing the descriptions, functions, processes, proposals, methods and / or operational flows disclosed in this document. Here, (one or more) processors 102 and (one or more) memories 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). (One or more) transceivers 106 may be connected to (one or more) processors 102 and transmit and / or receive radio signals through (one or more) antennas 108. Each transceiver 106 may include a transmitter and / or a receiver. (One or more) transceivers 106 may be used interchangeably with (one or more) radio frequency (RF) units. In the present disclosure, a wireless device may represent a communication modem / circuit / chip.

[0204] 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 (one or more) processors 202 may control the (one or more) memories 204 and / or the (one or more) transceivers 206, and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operation flows disclosed in this document. For example, the (one or more) processors 202 may process the information in the (one or more) memories 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the (one or more) transceivers 206. The (one or more) processors 202 may receive a radio signal including fourth information / signals through the (one or more) transceivers 106, and then store the information obtained by processing the fourth information / signals in the (one or more) memories 204. The (one or more) memories 204 may be connected to the (one or more) processors 202, and may store various information related to the operation of the (one or more) processors 202. For example, (one or more) memories 204 may store software code including commands for executing part or all of the processing controlled by (one or more) processors 202 or for executing the descriptions, functions, processes, proposals, methods and / or operational flows disclosed in this document. Here, (one or more) processors 202 and (one or more) memories 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). (One or more) transceivers 206 may be connected to (one or more) processors 202 and transmit and / or receive radio signals through (one or more) antennas 208. Each transceiver 206 may include a transmitter and / or a receiver. (One or more) transceivers 206 may be used interchangeably with (one or more) RF units. In the present disclosure, a wireless device may represent a communication modem / circuit / chip.

[0205] Below, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but are not limited to, 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 description, function, process, proposal, method, and / or operation flow disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the description, function, process, proposal, method, and / or operation flow disclosed in this document. 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 description, function, process, proposal, method, and / or operation flow disclosed in this document, 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 operating procedures disclosed in this document.

[0206] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. 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 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. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document may be included in one or more processors 102 and 202 or stored in one or more memories 104 and 204, thereby being driven by 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.

[0207] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and may store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 may 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 may be located inside and / or outside one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0208] One or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels mentioned in the method and / or operation flow 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 mentioned in the description, function, process, proposal, method, and / or operation flow 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 perform control so that one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information and / or radio signals / channels mentioned in the description, functions, processes, proposals, methods and / or operation flows disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received radio signals / channels, etc. from RF band signals to baseband signals to process received user data, control information, radio signals / channels, etc. using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0209] Fig. 20 A signal processing circuit for transmitting a signal according to an embodiment of the present disclosure is shown.

[0210] Reference Fig. 20 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). Fig. 20 Operation / function, not limited to Fig.19 The processor (102, 202) and / or the transceiver (106, 206) may be Fig.19The processor (102, 202) and / or the transceiver (106, 206) are implemented Fig. 20 For example, you can Fig.19 The processor (102, 202) implements blocks 1010 to 1060. Alternatively, Fig.19 The processor (102, 202) implements blocks 1010 to 1050 and can be implemented by Fig.19 The transceiver (106, 206) is used to implement box 1060.

[0211] Can be through Fig. 20 The signal processing circuit (1000) converts the codeword into a radio signal. Herein, 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 through various physical channels (e.g., PUSCH and PDSCH).

[0212] 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) for the complex modulation symbols. Alternatively, the precoder 1040 may perform precoding without performing transform precoding.

[0213] 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 transmitted 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 up-converter.

[0214] Can be used with Fig. 20 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. Fig.19 100, 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 illustrated) for receiving a signal may include a signal restorer, a resource demapper, a post-encoder, a demodulator, a descrambler, and a decoder.

[0215] Fig.21 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 Fig.18 ).

[0216] Reference Fig.21 , the wireless device (100, 200) may correspond to Fig.19 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 storage unit (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 Fig.19 One or more processors (102, 202) and / or one or more memories (104, 204) of the present invention. For example, the transceiver(s) (114) may include Fig.19The 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 storage unit (130). The control unit (120) can transmit the information stored in the storage unit (130) to the outside (e.g., other communication devices) via the communication unit (110) through a wireless / wired interface, or store the information received from the outside (e.g., other communication devices) via the communication unit (110) through a wireless / wired interface in the storage unit (130).

[0217] The additional component (140) may be configured in various ways depending on the type of the 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 ( Fig.18 100a), vehicles ( Fig.18 100b-1 and 100b-2), XR devices ( Fig.18 100c), handheld devices ( Fig.18 100d), household appliances ( Fig.18 100e), IoT devices ( Fig.18 100f), digital broadcasting terminals, hologram equipment, public safety equipment, MTC equipment, medical equipment, fintech equipment (or financial equipment), security equipment, climate / environmental equipment, AI servers / equipment ( Fig.18 400), BS( Fig.18 200), network nodes, etc. Depending on the use case / service, the wireless device can be used in a mobile or fixed place.

[0218] exist Fig.21In the wireless device (100, 200), 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 wirelessly connected 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 by wire, and the control unit (120) and the first unit (e.g., 130, 140) can be wirelessly connected 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.

[0219] Hereinafter, the implementation will be described in detail with reference to the accompanying drawings. Fig.21 .

[0220] Fig. 22 A handheld device according to an embodiment of the present disclosure is shown. The handheld device may include a smart phone, a smart pad, a wearable device (e.g., a smart watch 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).

[0221] Reference Fig. 22 The handheld device (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a storage unit (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 Fig.21 Frame 110 to 130 / 140.

[0222] The communication unit 110 may transmit and receive signals (e.g., data signals and control signals) to and from other wireless devices or BSs. The control unit 120 may perform various operations by controlling the constituent elements of the handheld device 100. The control unit 120 may include an application processor (AP). The storage unit 130 may store data / parameters / programs / codes / commands required to drive the handheld device 100. The storage unit 130 may store input / output data / information. The power supply unit 140a may supply power to the handheld device 100 and include a wired / wireless charging circuit, a battery, etc. The interface unit 140b may support the connection of the handheld device 100 to other external devices. The interface unit 140b may include various ports (e.g., audio I / O ports and video I / O ports) for connecting to external devices. The I / O unit 140c may input or output video information / signals, audio information / signals, data and / or information input by a user. The I / O unit 140c may include a camera, a microphone, a user input unit, a display unit 140d, a speaker and / or a tactile module.

[0223] 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 storage unit 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 storage unit 130, and can be output as various types (e.g., text, voice, image, video, or tactile) through the I / O unit 140.

[0224] Fig.23 A vehicle or autonomous vehicle according to an embodiment of the present disclosure is shown. The vehicle or autonomous vehicle may be implemented by a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0225] Reference Fig.23 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 Fig.21 Frame 110 / 130 / 140.

[0226] The communication unit 110 may transmit and receive signals (e.g., data signals and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. The control unit 120 may perform various operations by controlling elements of the vehicle or autonomous vehicle 100. The control unit 120 may include an electronic control unit (ECU). The drive unit 140a may 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 device, etc. The power supply unit 140b may supply power to the vehicle or autonomous vehicle 100, and may include a wired / wireless charging circuit, a battery, etc. The sensor unit 140c may acquire vehicle status, external environment information, user information, etc. The sensor unit 140c 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 position module, a vehicle forward / reverse 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 140d may implement a technology for maintaining a lane in which the vehicle is traveling, a technology for automatically adjusting a speed (e.g., adaptive cruise control), a technology for autonomously driving along a determined path, a technology for driving by automatically setting a path when a destination is set, and the like.

[0227] For example, the communication unit 110 may receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d may generate an autonomous driving path and a driving plan from the acquired data. The control unit 120 may control the drive unit 140a so that the vehicle or the autonomous driving vehicle 100 may move along the autonomous driving path according to the driving plan (e.g., speed / direction control). In the middle of autonomous driving, the communication unit 110 may aperiodically / periodically acquire the most recent traffic information data from an external server and acquire surrounding traffic information data from adjacent vehicles. In the middle of autonomous driving, the sensor unit 140c may acquire vehicle status and / or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving path and driving plan based on the newly acquired data / information. The communication unit 110 may transmit information about the vehicle position, autonomous driving path, and / or driving plan to an external server. The external server may predict traffic information data using AI technology, etc. based on information collected from the vehicle or autonomous driving vehicle, and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0228] The claims in this specification may be combined in various ways. For example, the technical features in the method claims of this specification may be combined to be implemented or performed in a device, and the technical features in the device claims may 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 may 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 may 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: performing at least one sidelink transmission to a second device; receiving negative acknowledgement (NACK) information related to the at least one sidelink transmission from the second device; determining whether to transmit a message for requesting retransmission resources based on a remaining latency budget associated with the at least one sidelink transmission and a preconfigured delay time threshold, The pre-configured delay time threshold includes a minimum delay time required for requesting a retransmission resource and allocating the retransmission resource.

2. The method according to claim 1, wherein: The remaining latency budget associated with the at least one sidelink transmission is equal to or greater than the preconfigured delay threshold.

3. The method according to claim 2, further comprising: Based on the remaining latency budget associated with the at least one sidelink transmission being equal to or greater than the preconfigured delay time threshold, a message requesting retransmission resources is transmitted to a base station.

4. The method according to claim 1, wherein: The remaining latency budget associated with the at least one sidelink transmission is less than the preconfigured delay threshold.

5. The method according to claim 4, wherein: Based on the remaining latency budget associated with the at least one sidelink transmission being less than the preconfigured delay time threshold, the first device determines not to transmit a message for requesting retransmission resources and stops the at least one sidelink transmission.

6. The method according to claim 4, further comprising: performing a mode 2 based retransmission based on the remaining latency budget associated with the at least one sidelink transmission being less than the preconfigured delay threshold, and Wherein, the mode 2-based retransmission is performed based on resources allocated by the first device for sidelink transmission to the second device.

7. The method according to claim 6, wherein: The mode 2 based retransmission is performed based on a channel busy rate (CBR) measurement associated with the at least one sidelink transmission being equal to or less than a preconfigured threshold.

8. The method according to claim 6, wherein: The mode 2 based retransmission is performed based on a channel quality value associated with the at least one sidelink transmission being greater than a preconfigured threshold.

9. The method according to claim 6, wherein: Based on a channel quality value associated with the at least one sidelink transmission being equal to or less than a preconfigured threshold, the mode 2 based retransmission is stopped.

10. The method according to claim 1, wherein: The message for requesting retransmission resources is any one of a scheduling request or Hybrid Automatic Repeat Request (HARQ) NACK information received from the second device.

11. The method according to claim 1, wherein: Performing at least one sidelink transmission to the second device includes: transmitting first information related to retransmission to a base station; receiving, from the base station, information related to initial transmission resources and second information related to retransmission resources; and performing the at least one sidelink transmission based on the information related to the initial transmission resource and the second information related to the retransmission resource, The first information includes at least one of the following: side link channel state information, interference level information, congestion level information, reference signal received power (RSRP) information related to the side link transmission, reference signal received quality (RSRQ) information related to the side link transmission, or received signal strength indicator (RSSI) information related to the side link transmission, and The second information includes the number of retransmission resources determined based on the first information.

12. The method according to claim 1, wherein: Performing at least one sidelink transmission to the second device includes: transmitting, to a base station, a number of retransmission resources determined based on first information related to retransmission; receiving, from the base station, information related to initial transmission resources and second information related to retransmission resources; and performing the at least one sidelink transmission based on the information related to the initial transmission resource and the second information related to the retransmission resource; The first information includes at least one of the following: side link channel state information, interference level information, congestion level information, reference signal received power (RSRP) information related to the side link transmission, reference signal received quality (RSRQ) information related to the side link transmission, or received signal strength indicator (RSSI) information related to the side link transmission.

13. A first device for performing 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: performing at least one sidelink transmission to a second device; receiving negative acknowledgement (NACK) information related to the at least one sidelink transmission from the second device; as well as determining whether to transmit a message for requesting retransmission resources based on a remaining latency budget associated with at least one sidelink transmission and a preconfigured delay threshold, The pre-configured delay time threshold includes a minimum delay time required for requesting a retransmission resource and allocating the retransmission resource.

14. A device configured to control a first user equipment (UE), the device comprising: one or more processors; as well as one or more memories operably connected to the one or more processors and storing instructions, wherein the one or more processors execute the instructions to: performing at least one sidelink transmission to a second UE; receiving negative acknowledgement (NACK) information related to the at least one sidelink transmission from the second UE; as well as determining whether to transmit a message for requesting retransmission resources based on a remaining latency budget associated with the at least one sidelink transmission and a preconfigured delay time threshold, The pre-configured delay time threshold includes a minimum delay time required for requesting a retransmission resource and allocating the retransmission resource.

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