Methods and apparatus for performing DTX-based RLF operations in NR V2X

Abstract

An operation method for a first device (100) in a wireless communication system is proposed. The method may include the following steps: transmitting a Physical Secondary Link Control Channel (PSCCH) to a second device (200); transmitting a Physical Secondary Link Shared Channel (PSSCH) to the second device (200) based on the PSCCH; determining a Physical Secondary Link Feedback Channel (PSFCH) resource associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH; and declaring a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first device (100) and the second device (200) based on the Discontinuous Transmission (DTX) counter reaching a maximum DTX-related threshold.

Description

Technical Field

[0001] This disclosure relates to wireless communication systems. Background Technology

[0002] Secondary Link (SL) communication is a communication scheme that establishes a direct link between User Equipments (UEs) and allows UEs to directly exchange voice and data without the intervention of Evolved Node Bs (eNBs). SL communication is being considered as a solution to the eNB overhead caused by the rapid growth of data traffic.

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

[0004] Furthermore, the increasing demand for larger communication capacity from various communication devices has led to a growing need for enhanced mobile broadband communications compared to traditional radio access technologies (RATs). Consequently, the design of communication systems for UEs or services sensitive to reliability and latency is under discussion. Next-generation radio access technologies based on enhanced mobile broadband communications, massive machine-type communications (MTC), and ultra-reliable low latency communications (URLLC) can be termed novel RATs or NRs (new radio technologies). In this paper, NR can also support vehicle-to-everything (V2X) communications.

[0005] Figure 1 This is a diagram used to describe NR-based V2X communication compared to the RAT-based V2X communication previously used. Figure 1 The implementation methods can be combined with various implementation methods of this disclosure.

[0006] Regarding V2X communication, when discussing the RAT used prior to NR, the focus was on schemes that provided security services based on V2X messages such as BSM (Basic Security Message), CAM (Cooperation Awareness Message), and DENM (Distributed Environment Notification Message). V2X messages can include location information, dynamic information, attribute information, etc. For example, a UE can send periodic message type CAM and / or event-triggered message type DENM to another UE.

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

[0008] Subsequently, various V2X scenarios were proposed in NR regarding V2X communication. These scenarios could include vehicle platooning, advanced driver assistance, extended sensors, and remote driving.

[0009] For example, based on vehicle platooning, vehicles can move together by dynamically forming groups. For example, to perform platooning operations, vehicles belonging to the group can receive periodic data from the leading vehicle. For example, vehicles belonging to the group can use periodic data to decrease or increase the interval between vehicles.

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

[0011] For example, based on extended sensors, raw data, processed data, or real-time video data acquired through local sensors can be exchanged between UEs (User Equipment) and / or V2X application servers, including vehicles, logical entities, and pedestrians. Therefore, for example, vehicles can identify a further improved environment compared to environments detected using self-sensors.

[0012] For example, based on remote driving, a remote driver or V2X application can operate or control a remote vehicle in hazardous environments or for a person who cannot drive. For instance, if routes such as public transportation are predictable, cloud-based driving can be used for the operation or control of remote vehicles. Additionally, access to cloud-based backend service platforms can be considered for remote driving.

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

[0014] Technical solution

[0015] According to an embodiment, a method for operating a first device 100 in a wireless communication system is proposed. The method may include the following steps: transmitting a Physical Secondary Link Control Channel (PSCCH) to a second device 200; transmitting a Physical Secondary Link Shared Channel (PSSCH) to the second device 200 based on the PSCCH; determining a Physical Secondary Link Feedback Channel (PSFCH) resource associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH; and declaring a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first device 100 and the second device 200 based on a Discontinuous Transmission (DTX) counter reaching a maximum threshold associated with the DTX.

[0016] The effect of this disclosure

[0017] User equipment (UE) can perform SL communication efficiently. Attached Figure Description

[0018] Figure 1 This is a diagram used to describe NR-based V2X communication compared to the RAT-based V2X communication previously used.

[0019] Figure 2 The structure of an NR system according to an embodiment of the present disclosure is shown.

[0020] Figure 3 A radio protocol architecture according to an embodiment of this disclosure is shown.

[0021] Figure 4 The structure of an NR radio frame according to an embodiment of the present disclosure is shown.

[0022] Figure 5 The structure of a time slot for an NR frame according to an embodiment of the present disclosure is shown.

[0023] Figure 6 An example of a BWP according to an embodiment of this disclosure is shown.

[0024] Figure 7 A UE performing V2X or SL communication according to an embodiment of this disclosure is shown.

[0025] Figure 8 The process of a UE performing V2X or SL communication based on a transmission mode according to an embodiment of the present disclosure is illustrated.

[0026] Figure 9 Three broadcast types according to embodiments of this disclosure are shown.

[0027] Figure 10A method is shown based on an embodiment of the present disclosure for a UE that has reserved one or more transmission resources to inform another UE of the one or more transmission resources(s).

[0028] Figure 11 The process of declaring an RLF by the MAC layer of the TX UE according to an embodiment of the present disclosure is illustrated.

[0029] Figure 12 The process of initializing the DTX counter by the MAC layer of the TX UE according to an embodiment of the present disclosure is shown.

[0030] Figure 13 The process of a first device performing wireless communication according to an embodiment of the present disclosure is illustrated.

[0031] Figure 14 The process of a second device performing wireless communication according to an embodiment of the present disclosure is illustrated.

[0032] Figure 15 A communication system 1 based on an embodiment of the present disclosure is shown.

[0033] Figure 16 A wireless device based on an embodiment of the present disclosure is shown.

[0034] Figure 17 A signal processing circuit for transmitting signals based on an embodiment of the present disclosure is shown.

[0035] Figure 18 Another example of a wireless device based on an embodiment of the present disclosure is shown.

[0036] Figure 19 A handheld device based on an embodiment of the present disclosure is shown.

[0037] Figure 20 A vehicle or autonomous vehicle according to an embodiment of this disclosure is shown. Detailed Implementation

[0038] In this disclosure, "A or B" may mean "A only", "B only", or "both A and B". In other words, in this disclosure, "A or B" can be interpreted as "A and / or B". For example, in this disclosure, "A, B or C" may mean "A only", "B only", "C only", or "any combination of A, B, and C".

[0039] The forward slash ( / ) or comma used in this disclosure can mean "and / or". For example, "A / B" can mean "A and / or B". Therefore, "A / B" can mean "A only", "B only", or "both A and B". For example, "A, B, C" can mean "A, B, or C".

[0040] In this disclosure, "at least one of A and B" may mean "only A", "only B" or "both A and B". Furthermore, in this disclosure, the expression "at least one of A or B" or "at least one of A and / or B" may be interpreted as "at least one of A and B".

[0041] Additionally, in this disclosure, "at least one of A, B, and C" may mean "A only", "B only", "C only" or "any combination of A, B, and C". Furthermore, "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".

[0042] Additionally, the brackets used in this disclosure may mean "for example". Specifically, when indicated as "Control Message (PDCCH)", this may mean that "PDCCH" is cited as an example of "Control Message". In other words, "Control Message" in this disclosure is not limited to "PDCCH", and "PDDCH" may be cited as an example of "Control Message". Specifically, when indicated as "Control Message (i.e., PDCCH)", this may also mean that "PDCCH" is cited as an example of "Control Message".

[0043] The technical features described in one of the accompanying drawings in this specification may be implemented individually or simultaneously.

[0044] The technologies 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), and Single Carrier Frequency Division Multiple Access (SC-FDMA). 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 Rate GSM Evolution (EDGE). OFDMA can be implemented using radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Evolved UTRA (E-UTRA). IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with IEEE 802.16e-based systems. UTRA is part of the Universal Mobile Telecommunications System (UMTS). The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of the 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.

[0045] 5G NR is a successor technology to LTE-A, corresponding to a new type of mobile communication system with high performance, low latency, and high availability. 5G NR can use all available spectrum resources, including low-frequency bands below 1 GHz, mid-frequency bands from 1 GHz to 10 GHz, and high-frequency bands above 24 GHz (millimeter waves).

[0046] For clarity, the following description will focus primarily on LTE-A or 5G NR. However, the technical features of embodiments according to this disclosure are not limited thereto.

[0047] Figure 2 The structure of an NR system according to an embodiment of this disclosure is shown. Figure 2 The implementation methods can be combined with various implementation methods of this disclosure.

[0048] Reference Figure 2The Next Generation Radio Access Network (NG-RAN) may include a BS 20 that provides user plane and control plane protocol termination to UE 10. For example, BS 20 may include a Next Generation Node B (gNB) and / or an Evolved Node B (eNB). For example, UE 10 may be fixed or mobile and may be referred to by other terms such as mobile station (MS), user terminal (UT), subscriber station (SS), mobile terminal (MT), radio device, etc. For example, BS may be referred to as a fixed station communicating with UE 10 and may be referred to by other terms such as base transceiver system (BTS), access point (AP), etc.

[0049] Figure 2 The implementation example illustrates the case involving only the gNB. BS 20 can interconnect via the Xn interface. BS 20 can interconnect via the fifth-generation (5G) core network (5GC) and the NG interface. More specifically, BS 20 can connect to the Access and Mobility Management Function (AMF) 30 via the NG-C interface and can connect to the User Plane Function (UPF) 30 via the NG-U interface.

[0050] The radio interface protocol layer between the UE and the network can be classified into Layer 1 (L1), Layer 2 (L2), and Layer 3 (L3) based on the well-known Open Systems Interconnection (OSI) model in communication systems. The Physical (PHY) layer, belonging to Layer 1, provides information transmission services using physical channels, while the Radio Resource Control (RRC) layer, located in Layer 3, controls the radio resources between the UE and the network. For this purpose, the RRC layer exchanges RRC messages between the UE and the BS layer.

[0051] Figure 3 A radio protocol architecture based on an embodiment of this disclosure is shown. Figure 3 The implementation methods can be combined with various implementation methods of this disclosure. Specifically, Figure 3 (a) shows the radio protocol stack for the user plane used for Uu communication, and Figure 3 (b) shows the radio protocol stack for the control plane used for Uu communication. Figure 3 (c) shows the radio protocol stack for the user plane used for SL communication, and Figure 3 (d) in the diagram shows the radio protocol stack for the control plane used for SL communication.

[0052] Reference Figure 3The physical layer provides information transmission services to the upper layers through physical channels. The physical layer connects to the Media Access Control (MAC) layer, which is the upper layer, via transport channels. Data is transmitted between the MAC layer and the physical layer via transport channels. Transport channels are classified according to how data is transmitted through the radio interface and what characteristics of the data are transmitted.

[0053] Data is transmitted between different physical layers (i.e., the PHY layer of the transmitter and the PHY layer of the receiver) via a physical channel. The physical channel can be modulated using an orthogonal frequency division multiplexing (OFDM) scheme, and the physical channel uses time and frequency as radio resources.

[0054] The MAC layer provides services to the Radio Link Control (RLC) layer, which is higher than the MAC layer, via logical channels. The MAC layer provides the ability to map multiple logical channels to multiple transport channels. The MAC layer also provides logical channel multiplexing by mapping multiple logical channels to a single transport channel. The MAC layer provides data transmission services through logical channels.

[0055] The RLC layer performs concatenation, segmentation, and reassembly of Radio Link Control Service Data Units (RLC SDUs). To ensure the different Quality of Service (QoS) required by the Radio Bearer (RB), the RLC layer provides three types of operating modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provides error correction through Automatic Repeat Request (ARQ).

[0056] The Radio Resource Control (RRC) layer is defined only in the control plane. The RRC layer is used to control the configuration, reconfiguration, and release of logical, transport, and physical channels associated with RBs. RBs are logical paths for data transmission between the UE and the network, provided by Layer 1 (i.e., the Physical Layer or PHY Layer) and Layer 2 (i.e., the MAC Layer, RLC Layer, Packet Data Convergence Protocol (PDCP) Layer, and Serving Data Adaptation Protocol (SDAP) Layer).

[0057] The Packet Data Convergence Protocol (PDCP) in the user plane performs functions including user data transmission, header compression, and encryption. The Packet Data Convergence Protocol (PDCP) in the control plane performs functions including control plane data transmission and encryption / integrity protection.

[0058] The Service Data Adaptation Protocol (SDAP) layer is defined only in the user plane. The SDAP layer performs the mapping between Quality of Service (QoS) streams and Data Radio Bearers (DRBs), as well as the QoS Stream ID (QFI) tagging in both DL and UL packets.

[0059] The configuration of an Radio Bearer (RB) refers to the processing used to specify the radio protocol layer and channel attributes to provide specific services, as well as to determine the corresponding detailed parameters and operating methods. RBs can then be classified into two types: Signaling Radio Bearers (SRBs) and Data Radio Bearers (DRBs). SRBs are used as paths for transmitting RRC messages in the control plane, while DRBs are used as paths for transmitting user data in the user plane.

[0060] When an RRC connection is established between the UE's RRC layer and the E-UTRAN's RRC layer, the UE is in the RRC connected (RRC_CONNECTED) state; otherwise, the UE can be in the RRC idle (RRC_IDLE) state. In the NR case, an additional RRC inactive (RRC_INACTIVE) state is defined, and a UE in the RRC_INACTIVE state can maintain its connection with the core network while releasing its connection with the BS.

[0061] The downlink transport channels for sending (or transmitting) data from the network to the UE include the Broadcast Channel (BCH) for transmitting system information and the Shared Downlink Channel (SCH) for transmitting other user service or control messages. Service or control messages for downlink multicast or broadcast services can be sent via the downlink SCH or via a separate downlink multicast channel (MCH). Furthermore, the uplink transport channels for sending (or transmitting) data from the UE to the network include the Random Access Channel (RACH) for transmitting initial control messages and the Shared Uplink Channel (SCH) for transmitting other user service or control messages.

[0062] Examples of logical channels that belong to a higher layer than the transport channel and are mapped to the transport channel may include the Broadcast Control Channel (BCCH), Paging Control Channel (PCCH), Common Control Channel (CCCH), Multicast Control Channel (MCCH), Multicast Service Channel (MTCH), etc.

[0063] Figure 4 The structure of an NR radio frame according to an embodiment of the present disclosure is shown. Figure 4 The implementation methods can be combined with various implementation methods of this disclosure.

[0064] Reference Figure 4 In NR, radio frames can be used to perform uplink and downlink transmissions. A radio frame is 10 ms long and can be defined as consisting of two half-frames (HF). A half-frame can include five 1 ms 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).

[0065] With normal CP, each time slot can include 14 symbols. With extended CP, each time slot can include 12 symbols. In this paper, symbols can include OFDM symbols (or CP-OFDM symbols) and single-carrier-FDMA (SC-FDMA) symbols (or Discrete Fourier Transform Extended OFDM (DFT-s-OFDM) symbols).

[0066] Table 1 below illustrates the number of time slots (N) per symbol based on the SCS setting (μ) under normal CP conditions. slot symb ), Number of time slots per frame (N) frame,μ slot ) and the number of time slots per subframe (N) subframe,μ slot ).

[0067] [Table 1]

[0068] <![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

[0069] Table 2 shows examples of the number of symbols per slot, the number of slots per frame, and the number of slots per subframe, based on SCS, when using extended CP.

[0070] [Table 2]

[0071] <![CDATA[SCS(15*2 μ )]]> <![CDATA[N slot symb ]]> <![CDATA[N frame,μ slot ]]> <![CDATA[N subframe,μ slot <!-- 5 -->]]> 60kHz (μ=2) 12 40 4

[0072] In NR systems, the OFDM(A) parameter sets (e.g., SCS, CP length, etc.) of multiple cells integrated into a UE can be configured differently. Therefore, the (absolute time) duration (or interval) of time resources (e.g., subframes, slots, or TTIs) consisting of the same number of symbols (collectively referred to as time units (TUs) for simplicity) can be configured differently in the integrated cells.

[0073] In NR, multiple parameter sets or SCSs can be supported to support various 5G services. For example, with an SCS of 15kHz, a wide range of traditional cellular bands can be supported, while with an SCS of 30kHz / 60kHz, dense urban areas, lower latency, and wider carrier bandwidth can be supported. With an SCS of 60kHz or higher, bandwidths greater than 24.25GHz can be used to overcome phase noise.

[0074] NR bands can be defined as two different types of frequency ranges. These two different types of frequency ranges can be FR1 and FR2. The values ​​of the frequency ranges can be changed (or varied), for example, the two different types of frequency ranges can be as shown in Table 3 below. In the frequency ranges used in NR systems, FR1 can mean "the range below 6 GHz," and FR2 can mean "the range above 6 GHz," and can also be referred to as millimeter wave (mmW).

[0075] [Table 3]

[0076] Frequency range specification Corresponding frequency range Subcarrier spacing (SCS) FR1 450MHz–6000MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0077] As mentioned above, the frequency range values ​​in an NR system can be changed (or varied). For example, as shown in Table 4 below, FR1 can include a bandwidth ranging from 410 MHz to 7125 MHz. More specifically, FR1 can 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 can include unlicensed frequency bands. Unlicensed frequency bands can be used for various purposes; for example, unlicensed frequency bands can be used for vehicle-specific communications (e.g., autonomous driving).

[0078] [Table 4]

[0079] Frequency range specification Corresponding frequency range Subcarrier spacing (SCS) FR1 410MHz–7125MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0080] Figure 5 The structure of a time slot for an NR frame according to an embodiment of this disclosure is shown. Figure 5 The implementation methods can be combined with various implementation methods of this disclosure.

[0081] Reference Figure 5 A time slot comprises multiple symbols in the time domain. For example, in normal CP, a time slot may include 14 symbols. In extended CP, a time slot may include 12 symbols. Alternatively, in normal CP, a time slot may include 7 symbols. However, in extended CP, a time slot may include 6 symbols.

[0082] A carrier comprises 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 portion (BWP) can be defined as multiple consecutive (physical) resource blocks ((P)RBs) in the frequency domain, and a BWP can correspond to a set of parameters (e.g., SCS, CP length, etc.). A carrier can include up to N BWPs (e.g., 5 BWPs). Data communication can be performed via active BWPs. Each element can be referred to as a resource element (RE) in the resource grid, and a complex symbol can be mapped to each element.

[0083] The bandwidth portion (BWP) and carrier will be described in detail below.

[0084] A BWP can be a contiguous set of Physical Resource Blocks (PRBs) within a given set of parameters. A PRB can be a contiguous set of Common Resource Blocks (CRBs) for a given set of parameters on a given carrier.

[0085] For example, a BWP can be at least one of an active BWP, an initial BWP, and / or a default BWP. For example, a UE may not monitor downlink radio link quality in DL BWPs other than the active DL BWP on the primary cell (PCell). For example, a UE may not receive PDCCH, Physical Downlink Shared Channel (PDSCH), or Channel State Information-Reference Signal (CSI-RS) (excluding RRM) other than the active DL BWP. For example, a UE may not trigger Channel State Information (CSI) reports for inactive DL BWPs. For example, a UE may not transmit Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH) other than the active UL BWP. For example, in the downlink case, the initial BWP can be given as a continuous set of RBs (configured by the Physical Broadcast Channel (PBCH)) for the Remaining Minimal System Information (RMSI) Control Resource Set (CORESET). For example, in the uplink case, the initial BWP can be given by the System Information Block (SIB) for the random access procedure. For example, a default BWP can be configured by a higher layer. For example, the initial value of the default BWP can be the initial DL BWP. To save energy, if the UE cannot detect downlink control information (DCI) during a specified period, the UE can switch its active BWP to the default BWP.

[0086] Furthermore, a BWP can be defined for an SL. The same SL BWP can be used for both transmission and reception. For example, a transmitting UE can transmit an SL channel or SL signal on a specific BWP, and a receiving UE can receive an SL channel or SL signal on a specific BWP. In a licensed carrier, the SL BWP can be defined separately from the Uu BWP, and the SL BWP can have separate configuration signaling from the Uu BWP. For example, a UE can receive configuration for an SL BWP from the BS / network. For example, a UE can receive configuration for a Uu BWP from the BS / network. SLBWPs are (pre-)configured on the carrier for NR V2X UEs outside coverage and RRC_IDLE UEs. For UEs in RRC_CONNECTED mode, at least one SL BWP can be activated on the carrier.

[0087] Figure 6 An example of a BWP according to an embodiment of this disclosure is shown. Figure 6 The implementation methods can be combined with various implementation methods of this disclosure. It is assumed that in... Figure 6 In this implementation, the number of BWPs is 3.

[0088] Reference Figure 6 A Common Resource Block (CRB) can be a carrier resource block numbered from one end of a carrier frequency band to the other. Alternatively, a Producer Resource Block (PRB) can be a resource block numbered within each BWP. Point A can indicate a common reference point for the resource block grid.

[0089] It can be determined by point A and the offset (N) relative to point A. start BWP ) and bandwidth (N size BWP To configure the BWP, point A can be an external reference point for the PRB of a carrier, with subcarrier 0 of all parameter sets (e.g., all parameter sets supported by the network on the corresponding carrier) aligned at point A. For example, offset can be the PRB distance between the lowest subcarrier in a given parameter set and point A. For example, bandwidth can be the number of PRBs in a given parameter set.

[0090] The following text will describe V2X or SL communication.

[0091] The secondary link synchronization signal (SLSS) can include a primary secondary link synchronization signal (PSSS) and a secondary secondary link synchronization signal (SSSS) as SL-specific sequences. The PSSS can be referred to as the secondary link primary synchronization signal (S-PSS), and the SSSS can be referred to as the secondary link secondary synchronization signal (S-SSS). For example, a 127-character M-sequence can be used for the S-PSS, and a 127-character Gold sequence can be used for the S-SSS. For example, the UE can use the S-PSS for initial signal detection and synchronization acquisition. For example, the UE can use the S-PSS and S-SSS for detailed synchronization acquisition and for detecting the synchronization signal ID.

[0092] The Physical Secondary Link Broadcast Channel (PSBCH) can be a (broadcast) channel used to transmit default (system) information that the UE must know before SL signal transmission / reception. For example, the default information could be related to SLSS, duplex mode (DM), Time Division Duplex (TDD) uplink / downlink (UL / DL) configuration, resource pool information, and application types related to SLSS, subframe offset, and broadcast information. For instance, to evaluate PSBCH performance in NR V2X, the PSBCH payload size can be 56 bits, including 24 bits of Cyclic Redundancy Check (CRC).

[0093] S-PSS, S-SSS, and PSBCH can be included in a block format that supports periodic transmission (e.g., SL synchronization signal (SS) / PSBCH block, hereinafter, secondary link synchronization signal block (S-SSB)). The S-SSB can have the same parameter set (i.e., SCS and CP lengths) as the Physical Secondary Link Control Channel (PSCCH) / Physical Secondary Link Shared Channel (PSSCH) in the carrier, and the transmission bandwidth can exist within a (pre-)configured secondary link (SL) BWP. For example, the S-SSB can have a bandwidth of 11 resource blocks (SBs). For example, the PSBCH can exist across 11 RBs. Additionally, the frequency location of the S-SSB can be (pre-)configured. Therefore, the UE does not need to perform hypothesis detection at the frequency to discover the S-SSB in the carrier.

[0094] Figure 7 A UE performing V2X or SL communication according to an embodiment of this disclosure is shown. Figure 7 The implementation methods can be combined with various implementation methods of this disclosure.

[0095] Reference Figure 7In V2X or SL communication, the term "UE" can generally refer to a user's UE. However, if a network device such as a BS transmits / receives signals according to a communication scheme between UEs, then the BS can also be considered a UE. For example, UE 1 could be a first device 100, and UE 2 could be a second device 200.

[0096] For example, UE 1 can select a resource element corresponding to a specific resource from a resource pool that represents a set of resource families. Additionally, UE 1 can transmit SL signals using resource elements. For instance, the resource pool in which UE 1 can transmit signals can be configured for UE 2, acting as a receiving UE, and UE 1's signals can be detected within that resource pool.

[0097] In this document, if UE 1 is within the connection range of the BS, the BS can inform UE 1 of the resource pool. Otherwise, if UE 1 is outside the connection range of the BS, another UE can inform UE 1 of the resource pool, or UE 1 can use a pre-configured resource pool.

[0098] Typically, resource pools can be configured in units of multiple resources, and each UE can select one or more units of resources to use in its SL signal transmission.

[0099] The following section describes resource allocation in SL.

[0100] Figure 8 The process of a UE performing V2X or SL communication based on a transmission mode according to an embodiment of this disclosure is illustrated. Figure 8 The implementation methods can be combined with various implementation methods of this disclosure. In various implementation methods of this disclosure, the transmission mode can be referred to as a mode or resource allocation mode. Hereinafter, for ease of explanation, in LTE, the transmission mode can be referred to as the LTE transmission mode. In NR, the transmission mode can be referred to as the NR resource allocation mode.

[0101] For example, Figure 8 (a) illustrates UE operation associated with LTE transmission mode 1 or LTE transmission mode 3. Alternatively, for example, Figure 8 (a) illustrates UE operations associated with NR resource allocation mode 1. For example, LTE transmission mode 1 can be applied to regular SL communication, and LTE transmission mode 3 can be applied to V2X communication.

[0102] For example, Figure 8 (b) illustrates UE operation associated with LTE transmission mode 2 or LTE transmission mode 4. Alternatively, for example, Figure 8 (b) shows the UE operation associated with NR resource allocation mode 2.

[0103] Reference Figure 8 In (a) of this document, in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, the BS can schedule SL resources for the UE to use for SL transmission. For example, the BS can perform resource scheduling for UE 1 via PDCCH (e.g., Downlink Control Information (DCI)) or RRC signaling (e.g., Configuration Grant Type 1 or Configuration Grant Type 2), and UE 1 can perform V2X or SL communication against UE 2 based on the resource scheduling. For example, UE 1 can send SCI to UE 2 via the Physical Secondary Link Control Channel (PSCCH), and subsequently send SCI-based data to UE 2 via the Physical Secondary Link Shared Channel (PSSCH).

[0104] Reference Figure 8 In (b) of this document, under LTE transmission mode 2, LTE transmission mode 4, or NR resource allocation mode 2, the UE can determine the SL transmission resource within the SL resources configured by the BS / network or the pre-configured SL resources. For example, the configured SL resources or the pre-configured SL resources can be a resource pool. For example, the UE can autonomously select or schedule resources for SL transmission. For example, the UE can perform SL communication by autonomously selecting resources from the configured resource pool. For example, the UE can autonomously select resources within a selection window by performing a sensing and resource (re)selection process. For example, sensing can be performed on a sub-channel basis. Furthermore, UE 1, which has autonomously selected resources from the resource pool, can send SCI to UE 2 via PSCCH, and subsequently send SCI-based data to UE 2 via PSSCH.

[0105] Figure 9 Three broadcast types according to embodiments of this disclosure are shown. Figure 9 The implementation methods can be combined with various implementation methods of this disclosure. Specifically, Figure 9 (a) shows broadcast SL communication. Figure 9 (b) shows unicast SL communication, and Figure 9 (c) illustrates multicast SL communication. In the case of unicast SL communication, a UE can perform one-to-one communication with another UE. In the case of multicast SL transmission, a UE can perform SL communication with one or more UEs in a group to which it belongs. In various embodiments of this disclosure, SL multicast communication can be replaced by SL multicast communication, SL one-to-many communication, etc.

[0106] The Hybrid Automatic Repeat Request (HARQ) process will be described below.

[0107] Error compensation schemes are used to ensure communication reliability. Examples of error compensation schemes include Forward Error Correction (FEC) and Automatic Repeat Request (ARQ). In FEC, errors at the receiver are corrected by appending additional error correction codes to the information bits. FEC has the advantage of low time delay and no additional information exchange between the sender and receiver; however, it also has the disadvantage of decreased system efficiency in good channel conditions. ARQ improves transmission reliability, but it also introduces time delay and decreases system efficiency in poor channel conditions.

[0108] The Hybrid Automatic Repeat Request (HARQ) scheme is a combination of the FEC and ARQ schemes. In the HARQ scheme, it is determined whether the data received by the physical layer contains unrecoverable errors, and a retransmission is requested after an error is detected, thereby improving performance.

[0109] In both SL unicast and SL multicast scenarios, HARQ feedback and HARQ combination in the physical layer can be supported. For example, when the receiving UE is operating in resource allocation mode 1 or 2, the receiving UE can receive the PSSCH from the sending UE, and the receiving UE can send HARQ feedback corresponding to the PSSCH to the sending UE using the secondary link feedback control information (SFCI) format via the physical secondary link feedback channel (PSFCH).

[0110] For example, SL HARQ feedback can be enabled for unicast. In this case, in a non-block group (non-CBG), the receiving UE can decode the PSCCH targeted at the receiving UE, and when the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE can generate a HARQ-ACK. The receiving UE can then send the HARQ-ACK to the sending UE. Conversely, if the receiving UE fails to successfully decode the transport block associated with the PSCCH after decoding the PSCCH targeted at the receiving UE, the receiving UE can generate a HARQ-NACK, and the receiving UE can send the HARQ-NACK to the sending UE.

[0111] For example, SL HARQ feedback can be enabled for multicast. For example, during non-CBG periods, two different types of HARQ feedback options can be supported for multicast.

[0112] (1) Multicast Option 1: After decoding the PSCCH targeted at the receiving UE, if the receiving UE fails to decode the transport block associated with the PSCCH, the receiving UE may send a HARQ-NACK to the sending UE via the PSFCH. Conversely, when the receiving UE decodes the PSCCH targeted at the receiving UE, and when the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE will not send a HARQ-ACK to the sending UE.

[0113] (2) Multicast Option 2: After decoding the PSCCH targeted at the receiving UE, if the receiving UE fails to decode the transport block associated with the PSCCH, the receiving UE may send a HARQ-NACK to the sending UE via the PSFCH. Furthermore, when the receiving UE decodes the PSCCH targeted at the receiving UE, and when the receiving UE successfully decodes the transport block associated with the PSCCH, the receiving UE may send a HARQ-ACK to the sending UE via the PSFCH.

[0114] For example, if multicast option 1 is used for SL HARQ feedback, all UEs performing multicast communication can share the PSFCH resource. For instance, UEs belonging to the same group can send HARQ feedback using the same PSFCH resource.

[0115] For example, if multicast option 2 is used for SL HARQ feedback, each UE performing multicast communication can use different PSFCH resources for HARQ feedback transmission. For instance, UEs belonging to the same group can send HARQ feedback using different PSFCH resources.

[0116] For example, when SL HARQ feedback is enabled for multicast, the receiving UE can determine whether to send HARQ feedback to the transmitting UE based on the transmit-receive (TX-RX) distance and / or the reference signal received power (RSRP).

[0117] For example, in multicast option 1, in the case of HARQ feedback based on TX-RX distance, if the TX-RX distance is less than or equal to the communication range requirement, the receiving UE may send the HARQ feedback in response to the PSSCH to the sending UE. Otherwise, if the TX-RX distance is greater than the communication range requirement, the receiving UE may not send the HARQ feedback in response to the PSSCH to the sending UE. For example, the sending UE may inform the receiving UE of its location via the SCI associated with the PSSCH. For example, the SCI associated with the PSSCH may be a second SCI. For example, the receiving UE may estimate or obtain the TX-RX distance based on the locations of the receiving UE and the sending UE. For example, the receiving UE may decode the SCI associated with the PSSCH, thus knowing the communication range requirement for the PSSCH.

[0118] For example, in resource allocation mode 1, the time (offset) between PSFCH and PSSCH can be configured or pre-configured. In unicast and multicast scenarios, if a retransmission is required on the SL, it can be indicated to the BS by a UE within the coverage area using PUCCH. The sending UE can send the indication to the serving BS in the form of a Scheduling Request (SR) / Buffer Status Report (BSR) instead of HARQACK / NACK. Furthermore, even if the BS does not receive this indication, it can still schedule SL retransmission resources for the UE. For example, in resource allocation mode 2, the time (offset) between PSFCH and PSSCH can be configured or pre-configured.

[0119] For example, from the perspective of UE transmission in a carrier, TDM between PSCCH / PSSCH and PSFCH can be allowed for the PSFCH format used for SL in a time slot. For example, a sequence-based PSFCH format with a single symbol can be supported. In this document, this single symbol may not be an AGC duration. For example, the sequence-based PSFCH format can be applied to both unicast and multicast.

[0120] For example, within a time slot associated with a resource pool, the PSFCH resource can be periodically configured for N time slot durations, or it can be pre-configured. For example, N can be configured to one or more values ​​greater than or equal to 1. For example, N can be 1, 2, or 4. For example, HARQ feedback for transmissions within a specific resource pool can be sent via PSFCH only on that specific resource pool.

[0121] For example, when a sending UE transmits a PSSCH to a receiving UE across time slots #X to #N, the receiving UE can send a HARQ feedback in response to the PSSCH to the sending UE in time slot #(N+A). For example, time slot #(N+A) may include PSFCH resources. In this document, for example, A may be the smallest integer greater than or equal to K. For example, K may be the number of logical time slots. In this case, K may be the number of time slots in the resource pool. Alternatively, for example, K may be the number of physical time slots. In this case, K may be the number of time slots inside or outside the resource pool.

[0122] For example, when a receiving UE sends a HARQ feedback on a PSFCH resource in response to a PSSCH sent by a transmitting UE to the receiving UE, the receiving UE can determine the frequency domain and / or code domain of the PSFCH resource based on implicit mechanisms in the configured resource pool. For example, the receiving UE can determine the frequency domain and / or code domain of the PSFCH resource based on at least one of the slot index associated with the PSCCH / PSSCH / PSFCH, the sub-channel associated with the PSCCH / PSSCH, or the identifier of each receiving UE in the group used to identify HARQ feedback based on multicast option 2. Alternatively / in addition, for example, the receiving UE can determine the frequency domain and / or code domain of the PSFCH resource based on at least one of SL RSRP, SINR, L1 source ID, and / or location information.

[0123] For example, when HARQ feedback transmission via the UE's PSFCH overlaps with HARQ feedback reception via the PSFCH, the UE can select either HARQ feedback transmission via the PSFCH or HARQ feedback reception via the PSFCH based on priority rules. For example, the priority rules can be based at least on the priority indication of the relevant PSCCH / PSSCH.

[0124] For example, when HARQ feedback transmissions via PSFCH overlap for multiple UEs, the UE can select a specific HARQ feedback transmission based on priority rules. For instance, the priority rules could be based on the lowest priority indication of the relevant PSCCH / PSSCH.

[0125] Furthermore, in various embodiments of this disclosure, the transmitting UE (i.e., the TX UE) can be a UE that transmits data to (one or more) (target) receiving UEs (i.e., (one or more) RX UEs). For example, the TX UE can be a UE that performs PSCCH transmission and / or PSSCH transmission. For example, the TX UE can be a UE that transmits (one or more) SLCSI-RS and / or SL CSI report request indications to (one or more) (target) RX UEs. For example, the TX UE can be a UE that sends (one or more) (predefined) reference signals (e.g., PSSCH demodulation reference signals (DM-RS)) and / or SL(L1) RSRP report request indications for SL(L1) RSRP measurements to (one or more) (target) RX UEs. For example, a TX UE may be a UE that transmits (control) channels (e.g., PSCCH, PSSCH, etc.) and / or transmits (one or more) reference signals (e.g., (one or more) DM-RS, (one or more) CSI-RS, etc.) for (one or more) SL radio link monitoring (RLM) operations and / or (one or more) SL radio link fault (RLF) operations for (one or more) target RX UEs via (control) channels.

[0126] Furthermore, in various embodiments of this disclosure, the receiving UE (i.e., the RX UE) can be a UE that sends SLHARQ feedback to (one or more) TX UEs based on whether data sent by (one or more) sending UEs (i.e., (one or more) TX UEs) has been successfully decoded and / or whether PSCCH (related to PSSCH scheduling) sent by (one or more) TX UEs has been successfully detected / decoded. For example, the RX UE can be a UE that performs SL CSI transmission to (one or more) TX UEs based on (one or more) SL CSI-RS and / or SL CSI report request indications received from (one or more) TX UEs. For example, the RX UE can be a UE that sends SL(L1) RSRP measurements to (one or more) TX UEs based on SL(L1) RSRP report request indications and / or (one or more) (predefined) reference signals received from (one or more) TX UEs. For example, the RX UE can be a UE that sends its own data to (one or more) TX UEs. For example, an RX UE can be a UE that performs one or more SL RLM operations and / or one or more SL RLF operations based on (pre-configured) (control) channels and / or through (control) channels on (one or more) reference signals received from (one or more) TX UEs.

[0127] Furthermore, in various embodiments of this disclosure, when the receiving UE sends SL HARQ feedback information for the PSSCH and / or PSCCH received from the sending UE, the following methods may be considered or partially considered. Here, for example, the corresponding scheme or some schemes may be applied only with restrictions when the receiving UE successfully decodes / detects the PSCCH used for scheduling the PSSCH.

[0128] Option 1: Send NACK message only when PSSCH decoding / reception fails.

[0129] Option 2: Send an ACK message when PSSCH decoding / reception is successful, or send a NACK message when it fails.

[0130] Furthermore, in various embodiments of this disclosure, for example, the TX UE can send at least one of the following information to the RX UE via the SCI. Here, for example, the TX UE can send at least one of the following information to the RX UE via a first SCI and / or a second SCI.

[0131] - PSSCH (and / or PSCCH) related resource allocation information (e.g., location / number of time / frequency resources, resource reservation information (e.g., time period)).

[0132] -SL CSI Report Request Indicator or SL(L1)RSRP (and / or SL(L1)RSRQ and / or SL(L1)RSSI) Report Request Indicator

[0133] - (on PSSCH) SL CSI send indicator (or SL(L1)RSRP (and / or SL(L1)RSRQ and / or SL(L1)RSSI) message send indicator)

[0134] Modulation and coding scheme (MCS) information

[0135] - Transmit power information

[0136] -L1 Destination ID information and / or L1 Source ID information

[0137] -SL HARQ process ID information

[0138] - New Data Indicator (NDI) information

[0139] -Redundant Version (RV) Information

[0140] - (Send service / packet related) QoS information (e.g., priority information)

[0141] - SL CSI-RS transmit indicator or the number of (transmitted) SL CSI-RS antenna port information

[0142] -TX UE location information or (as requested by SL HARQ) target RX UE location (or distance area information)

[0143] - Information regarding the decoding of data transmitted via PSSCH and / or reference signals (e.g., DM-RS, etc.) related to channel estimation. For example, information about the reference signals could be information related to the pattern of the (time-frequency) mapping resources of the DM-RS, rank information, antenna port index information, etc.

[0144] Furthermore, in various embodiments of this disclosure, for example, the PSCCH can be replaced / substituted by at least one of the SCI, the first SCI (first-level SCI), and / or the second SCI (second-level SCI), or vice versa. For example, the SCI can be replaced / substituted by at least one of the PSCCH, the first SCI, and / or the second SCI, or vice versa. For example, since the transmitting UE can send the second SCI to the receiving UE via the PSSCH, the PSSCH can be replaced / substituted by the second SCI and / or the PSCCH, or vice versa. For example, if the SCI configuration fields are divided into two groups considering the (relatively) high SCI payload size, the SCI including the first SCI configuration field group can be referred to as the first SCI or the first SCI, and the SCI including the second SCI configuration field group can be referred to as the second SCI or the second SCI. For example, the first SCI and the second SCI can be transmitted via different channels. For example, the transmitting UE can send the first SCI to the receiving UE via the PSCCH. For example, the second SCI can be sent to the receiving UE via (separate) PSCCH, or it can be sent via PSSCH along with the data in a piggyback manner.

[0145] On the other hand, in various embodiments of this disclosure, for example, "configuration" or "definition" can mean (via predefined signaling (e.g., SIB, MAC, RRC, etc.)) a (resource pool-specific) (pre)configuration from a base station or network. For example, "A is configured as" can mean "the base station / network sends information related to A to the UE." Or, for example, "A is configured as" can mean "A is specified via predefined signaling (e.g., PC5RRC) between UEs."

[0146] Furthermore, in various embodiments of this disclosure, for example, "RLF" can be interpreted as mutually extending to at least one of asynchronous (OOS) and synchronous (IS). Furthermore, in various embodiments of this disclosure, for example, a resource block (RB) can be replaced / replaced by a subcarrier, or vice versa. For example, packets or traffic can be replaced / replaced by a transport block (TB) or a Media Access Control Protocol Data Unit (MAC PDU) according to the transmission layer, or vice versa. For example, a code block group (CBG) can be replaced / replaced by a TB, or vice versa. For example, a source ID can be replaced / replaced by a destination ID, or vice versa. For example, an L1 ID can be replaced / replaced by an L2 ID, or vice versa. For example, an L1 ID can be an L1 source ID or an L1 destination ID. For example, an L2 ID can be an L2 source ID or an L2 destination ID.

[0147] Furthermore, in various embodiments of this disclosure, for example, the operation of the TX UE reserving / selecting / determining one or more retransmission resources may include: the operation of the TX UE reserving / selecting / determining one or more potential retransmission resources, wherein the actual use is determined based on SL HARQ feedback information received from one or more RX UEs.

[0148] Furthermore, in various embodiments of this disclosure, the sub-selection window may be replaced / replaced by the selection window and / or by a pre-configured number of resources configured within the selection window, or vice versa.

[0149] Furthermore, in various embodiments of this disclosure, SL MODE 1 can refer to a resource allocation method or communication method in which the base station directly schedules one or more SL transmission resources for the TX UE via predefined signaling (e.g., DCI or RRC messages). For example, SL MODE 2 can refer to a resource allocation method or communication method in which the UE independently selects one or more SL transmission resources from a resource pool configured or pre-configured by the base station or network. For example, a UE performing SL communication based on SL MODE 1 can be referred to as MODE 1 UE or MODE 1 TX UE, and a UE performing SL communication based on SL MODE 2 can be referred to as MODE 2 UE or MODE 2 TX UE.

[0150] Furthermore, in this disclosure, for example, a Dynamic Grant (DG) can be replaced / replaced by a Configurable Grant (CG) and / or a Semi-Permanent Scheduled (SPS) Grant, or vice versa. For example, a DG can be replaced / replaced by a combination of CG and SPS Grants, or vice versa. For example, a CG can include at least one of Configurable Grant (CG) Type 1 and / or Configurable Grant (CG) Type 2.

[0151] Furthermore, in various embodiments of this disclosure, the channel can be replaced by a signal, or vice versa. For example, transmitting / receiving the channel may include transmitting / receiving a signal. For example, transmitting / receiving a signal may include transmitting / receiving the channel. For example, broadcasting may be replaced by at least one of unicast, multicast, and / or broadcast, or vice versa. For example, the broadcast type may be replaced by at least one of unicast, multicast, and / or broadcast, or vice versa.

[0152] Furthermore, in various embodiments of this disclosure, resources may be replaced / alternated by time slots or symbols, or vice versa. For example, resources may include time slots and / or symbols.

[0153] Furthermore, in various embodiments of this disclosure, the priority can be replaced / substituted by at least one of Logical Channel Priority (LCP), latency, reliability, minimum required communication range, Priority Per Packet (PPPP), Sublink Radio Bearer (SLRB), QoS profile, QoS parameters and / or requirements, or vice versa.

[0154] Furthermore, in various embodiments of this disclosure, for example, for ease of description, the (physical) channel used when the RX UE sends at least one of the following information to the TX UE may be referred to as PSFCH.

[0155] -SL HARQ feedback, SL CSI, SL(L1)RSRP

[0156] Furthermore, when performing secondary link communication, the method by which the sending UE reserves or predetermines one or more transmission resources for one or more receiving UEs can be represented as follows.

[0157] For example, the transmitting UE can perform the reservation of one or more transmitting resources based on a chain. Specifically, for example, if the transmitting UE reserves K transmitting resources, the transmitting UE can send location information of fewer than K transmitting resources to one or more receiving UEs at any (or specific) transmitting time or time resource via an SCI sent to one or more receiving UEs. That is, for example, the SCI can include location information of fewer than K transmitting resources. Alternatively, for example, if the transmitting UE reserves K transmitting resources associated with a specific TB, the transmitting UE can send location information of fewer than K transmitting resources to one or more receiving UEs at any (or specific) transmitting time or time resource via an SCI sent to one or more receiving UEs. That is, the SCI can include location information of fewer than K transmitting resources. In this case, for example, performance degradation due to excessive SCI payload can be prevented by signaling the location information of fewer than K transmitting resources to one or more receiving UEs via an SCI sent by the transmitting UE at any (or specific) transmitting time or time resource.

[0158] Figure 10 A method is shown based on an embodiment of the present disclosure in which a UE that has reserved one or more transmission resources informs another UE of one or more transmission resources. Figure 10 The implementation methods can be combined with various implementation methods of this disclosure.

[0159] Specifically, for example, Figure 10 (a) illustrates a chain-based resource reservation method performed by the transmitting UE, when the value of K is equal to 4, by notifying (up to) the location information of up to two transmitting resources to (one or more) receiving UEs via an SCI. For example, Figure 10 (b) illustrates a chain-based resource reservation method performed by the transmitting UE to notify (up to) the location information of up to three transmitting resources via a single SCI to one or more receiving UEs when the value of K is equal to 4. For example, see reference Figure 10 In (a) and (b), the transmitting UE can notify the receiving UE(s) of the location information of the fourth transmission-related resources by sending / signaling the fourth transmission-related PSCCH to (one or more) receiving UEs only. For example, refer to Figure 10 In (a), the transmitting UE may additionally transmit / signal the location information of the fourth transmission-related resource to (one or more) receiving UEs via a fourth (or last) transmission-related PSCCH, and also transmit / signal the location information of the third transmission-related resource. For example, refer to Figure 10(b) The transmitting UE may additionally transmit / signal the location information of the fourth transmission-related resource to (one or more) receiving UEs via the fourth (or last) transmission-related PSCCH, and also transmit / signal the location information of the second and third transmission-related resources. In this case, for example, in Figure 10 In (a) and (b), if the transmitting UE can notify the receiving UE(s) of the location information of the fourth transmission-related resources by transmitting / signaling only the fourth (or last) transmission-related PSCCH, then the transmitting UE can configure or specify the fields / bits of the location information of the unused or remaining transmission resources(s) to a pre-configured value (e.g., 0). For example, in Figure 10 In (a) and (b), if the transmitting UE can send / signal to (one or more) receiving UEs only the location information of the fourth transmission-related resources via the fourth (or last) transmission-related PSCCH, then the transmitting UE can configure or specify the field / bit of the location information of (one or more) unused or remaining transmission resources as a pre-configured status / bit value indicating / representing the last transmission (out of the four transmissions).

[0160] Furthermore, for example, the transmitting UE can perform the reservation of (one or more) transmission resources on a block-by-block basis. Specifically, for example, if the transmitting UE reserves K transmission resources, the transmitting UE can send the location information of the K transmission resources to (one or more) receiving UEs at any (or specific) transmission time or time resource via an SCI sent to (one or more) receiving UEs. That is, the SCI can include the location information of the K transmission resources. For example, if the transmitting UE reserves K transmission resources associated with a specific TB, the transmitting UE can send the location information of the K transmission resources to (one or more) receiving UEs at any (or specific) transmission time or time resource via an SCI sent to (one or more) receiving UEs. That is, the SCI can include the location information of the K transmission resources. For example, Figure 10 (c) illustrates a method for block-based resource reservation by the transmitting UE to signal the location information of four transmitting resources to one or more receiving UEs via an SCI when the value of K is equal to 4.

[0161] According to existing technology, for example, on the TX UE side, when performing an SL RLF announcement operation based on DTX counter counting, it may be necessary to define a method for the TX UE's physical layer to report the DTX occurrence status to the Media Access Control (MAC) layer. For example, in this disclosure, the PHY layer may refer to the physical layer. Here, for example, DTX may include: the RX UE being unable to perform SCI decoding received from the TX UE and unable to send HARQ feedback information based on PSFCH to the TX UE; the TX UE not performing PSFCH reception / monitoring operations related to the MAC PDU sent by the TX UE according to priority rules; and / or the TX UE performing PSFCH reception / monitoring operations related to its sent MAC PDU but ultimately failing to detect them. For example, priority rules may include rules related to priorities between UL and SL, between LTE SL and NR SL, between multiple PSFCH TXs, and / or between PSFCH TX and PSFCH RX.

[0162] According to the embodiments of this disclosure, when the aforementioned DTX situation occurs, the physical layer of the TX UE cannot perform the operation of reporting SLHARQ information to the MAC layer. Here, the MAC layer implicitly interprets it as a DTX situation and may increment the DTX count value associated with the SL RLF declaration.

[0163] According to this disclosure, in order to support SL RLF operation, no additional information is generated that is exchanged between the PHY layer and the MAC layer, thereby reducing the complexity of UE implementation.

[0164] According to embodiments of this disclosure, for example, for each of a plurality of PSFCH reception opportunities, the UE can generate HARQ-ACK information to report to a higher layer. To generate HARQ-ACK information, the UE can be instructed to perform the following operations from the SCI format. When the broadcast type indication field value is "10", if the UE receives a PSFCH associated with SCI format 2-A, the UE can report HARQ-ACK information having the same value as the HARQ-ACK information determined by the UE from the reception of the PSFCH to a higher layer.

[0165] According to an embodiment of this disclosure, for each PSFCH reception timing associated with PSSCH transmission, when there is no PSFCH reception in the PSFCH reception timing, the sublink HARQ entity may have to increment numConsecutiveDTX by 1.

[0166] According to embodiments of this disclosure, UEs performing secondary link (SL) communication (e.g., unicast) can be configured to perform radio link failure (RLF) (and / or radio link monitoring; RLM) operations based on discontinuous transmission (DTX). Here, for example, DTX can be interpreted as a situation where the TX UE is unable to receive the Physical Secondary Link Shared Channel (PSSCH) (and / or Physical Secondary Link Control Channel (PSCCH)) and its associated Physical Secondary Link Feedback Channel (PSFCH) transmitted by the TX UE, and / or is unable to perform a PSFCH reception attempt.

[0167] For example, the DTX may include i) a situation where the RX UE is unable to decode the PSCCH sent by the TX UE and does not perform PSFCH transmission, and / or a situation where the RX UE does not perform (as expected by the TX UE) PSFCH transmission because it cannot perform PSCCH reception operation due to transmission of relatively high-priority uplink (UL) / SL channels / signals. This situation could be interpreted, for example, as a half-duplex problem and / or a problem related to UL / SL prioritization.

[0168] And / or, for example, DTX may include ii) the RX UE performing a PSFCH transmission related to a PSSCH (and / or PSCCH) sent by the TX UE, and the TX UE attempting to receive it, but failing (e.g., due to reasons such as degradation of the SL channel), and / or iii) the TX UE being unable to perform a PSFCH reception operation (sent by the RX UE) due to its own transmission operations. For example, the TX UE's transmission operations may include PSFCH transmissions related to relatively high-priority SL packets, relatively high-priority SL channel / signal transmissions, and / or relatively high-priority UL channel / signal transmissions. For example, this situation can be interpreted as a half-duplex problem and / or a problem related to UL / SL prioritization.

[0169] And / or, for example, DTX can be at least one of i) to iv), where iv) is a case where the RX UE omits the PSFCH transmission operation due to the transmission of a relatively high priority UL / SL channel / signal and / or the transmission of a relatively high priority SL packet-related PSFCH. The PSFCH may include the PSFCH associated with the PSSCH (and / or PSCCH) received from the TX UE. For example, this situation can be interpreted as a UL / SL prioritization problem.

[0170] According to embodiments of this disclosure, when consecutive DTXs occur due to a pre-configured (maximum) counting threshold (DTXNUM_TD), an RLF can be declared for the relevant session and / or PC5 link. For example, DTXNUM_TD can be configured specifically for (unicast) sessions and / or PC5 links.

[0171] For example, during DTX-based RLF (and / or RLM) operation, the TX UE can be configured to apply the following rules(s). Here, for example, a portion of the method / rule-related parameters proposed in this disclosure (e.g., whether DTXNUM_TD and / or whether it is applied to DTXNUM_TD) can be configured / limited differently (or independently) for service priority / type, (service) QoS requirements, (resource pool) congestion level (e.g., CBR; channel busy ratio), resource pool, broadcast type, Hybrid Automatic Repeat Request (HARQ) feedback scheme, SL operation mode (e.g., mode 1, mode 2), and / or HARQ feedback enabling (or disabling) Media Access Control (MAC) Protocol Data Units (PDUs) (and / or TBs; transport blocks). For example, service QoS requirements may include latency and reliability. For example, broadcast type may include unicast, multicast, and / or broadcast. For example, HARQ feedback scheme may include positive acknowledgment (ACK) / negative acknowledgment (NACK) feedback and / or NACK only (NACK ONLY) feedback. For example, in this disclosure, the MAC layer can be interpreted as an upper layer that extends to the physical (PHY) layer (e.g., the RRC layer).

[0172] According to embodiments of this disclosure, the PHY layer of the TX UE can be configured to report ACK or NACK information corresponding to the transmitted PSSCH and / or PSCCH to the MAC layer only when ACK or NACK information corresponding to the transmitted PSSCH and / or PSCCH is obtained. For example, when the PHY layer of the TX UE attempts a PSFCH reception operation and obtains ACK or NACK information based on successful PSFCH detection, it can be configured to report ACK or NACK information to the MAC layer. Alternatively, for example, when the PHY layer of the TX UE attempts to receive PSFCH but cannot detect PSFCH, it can be configured to report NACK information, DTX information, or pre-configured specific information / indicators to the MAC layer.

[0173] Here, for example, if the rules apply, when the PHY layer of the TX UE is unable to perform a PSFCH reception operation due to some of the reasons mentioned above (e.g., half-duplex issues and / or UL / SL priority issues) (and / or attempts to receive PSFCH but failure), this can be interpreted as not reporting SL HARQ-related information to the MAC layer. For example, SL HARQ-related information may include NACK, DTX (occurrence) information, and / or RLF-related information. For example, the situation where the PHY layer of the TX UE is unable to perform a PSFCH reception operation due to some of the reasons mentioned above (and / or attempts to receive PSFCH but failure) and does not report SL HARQ-related information to the MAC layer can take the same form as a blind retransmission operation disabled based on HARQ feedback. In this case, for example, even if the PHY layer does not report the aforementioned SL HARQ-related information, the MAC layer can still trigger / execute a retransmission operation against the PHY layer. For example, the triggering / execution of the retransmission operation could be due to the absence of ACK information related to the transmitted MAC PDU from the PHY layer.

[0174] Additionally, for example, in the aforementioned situations (e.g., when the PHY layer of the TX UE does not report SL HARQ-related information to the MAC layer), the MAC layer may count this as / treat it as a DTX occurrence and reflect it in whether to declare an RLF. Alternatively, for example, the MAC layer may not reflect this in whether to declare an RLF (considering that NACK information has been received). For example, it can be interpreted that the MAC layer only reflects the DTX information in the RLF declaration-related count when the PHY layer directly reports the DTX information.

[0175] For example, it can be configured to not report SL HARQ related information to the MAC layer if the service / packet priority (and / or reliability requirements) is higher or lower than a pre-configured threshold level, the latency requirement associated with the service / packet is shorter or longer than a pre-configured threshold, and / or when the (resource pool) congestion level is higher or lower than a pre-configured threshold level, or when the PHY layer of the TX UE is unable to perform PSFCH reception operation due to (some) of the above reasons (e.g., half-duplex issues and / or UL / SL priority issues) (and / or when attempting PSFCH reception but failing). Otherwise, it can be configured to report NACK information, DTX information, or pre-configured specific information / indicators.

[0176] According to embodiments of this disclosure, when the PHY layer of the TX UE is unable to perform PSFCH reception operation due to the aforementioned reasons (e.g., half-duplex issues and / or UL / SL priority issues) (and / or when attempting to receive PSFCH but failing), the PHY layer of the TX UE may report NACK information, DTX information, or pre-configured specific information / indicators to the MAC layer. Here, for example, when this rule applies, the content of the information reported to the MAC layer (and / or whether information is reported to the MAC layer) can be interpreted as different between the case where the PHY layer of the TX UE attempts to receive PSFCH but cannot detect PSFCH (e.g., the PHY layer of the TX UE reports DTX information, NACK information, or pre-configured specific information / indicators to the MAC layer, and / or the PHY layer of the TX UE does not report SL HARQ related information to the MAC layer) and the case where the PHY layer of the TX UE cannot perform PSFCH reception operation (e.g., when the PHY layer of the TX UE reports NACK information, DTX information, or pre-configured specific information / indicators to the MAC layer). In the above cases, for example, since the MAC layer has received NACK information, DTX information, or pre-configured specific information / indicators from the PHY layer, it triggers / executes a retransmission operation to the PHY layer, and it cannot be included in the DTX occurrence count associated with the RLF announcement.

[0177] According to embodiments of this disclosure, when the PHY layer of the TX UE is unable to perform PSFCH reception operation due to the aforementioned reasons (e.g., half-duplex issues and / or UL / SL priority issues) (and / or when attempting to receive PSFCH but failing), the PHY layer of the TX UE may report NACK information, DTX information, or pre-configured specific information / indicators to the MAC layer. Here, for example, when this rule applies, the content of the information reported to the MAC layer (and / or whether information is reported to the MAC layer) can be interpreted as different between the case where the PHY layer of the TX UE attempts to receive PSFCH but cannot detect PSFCH (e.g., the PHY layer of the TX UE reports DTX information, NACK information, or pre-configured specific information / indicators to the MAC layer, and / or the PHY layer of the TX UE does not report SL HARQ related information to the MAC layer) and the case where the PHY layer of the TX UE cannot perform PSFCH reception operation (e.g., when the PHY layer of the TX UE reports NACK information, DTX information, or pre-configured specific information / indicators to the MAC layer). In the above scenario, for example, since the MAC layer has received NACK information, DTX information, or pre-configured specific information / indicators from the PHY layer, it triggers / executes a retransmission operation to the PHY layer, and this can be included in the DTX occurrence count associated with the RLF announcement.

[0178] According to embodiments of this disclosure, requirements related to PSFCH detection, such as ACK-to-NACK error probability, NACK-to-ACK error probability, DTX-to-ACK probability, etc., can be defined differently (or independently) based on the HARQ feedback scheme, (packet-related) service priority / type, (packet-related) QoS requirements, (resource pool) congestion level (e.g., CBR), resource pool, broadcast type (e.g., unicast, multicast), SL operation mode (e.g., mode 1, mode 2), and / or the maximum number of retransmissions allowed. For example, the HARQ feedback scheme may include ACK / NACK feedback and / or NACK-only feedback. For example, (packet-related) QoS requirements may include latency and reliability. For example, the maximum number of retransmissions allowed may include the maximum number of retransmissions allowed related to (pre-configured) service / packet and / or LCH.

[0179] According to embodiments of this disclosure, when a Mode 1TX UE is unable to receive a PSFCH transmitted by an RX UE due to its own transmission operations, the Mode 1TX UE can be configured to report NACK information, DTX information, or pre-configured specific information / indicators via (pre-configured) PUCCH resources. For example, this situation can be interpreted as a UL / SL priority issue and / or a half-duplex issue. For instance, the Mode 1TX UE's own transmission operations may include PSFCH transmission related to relatively high-priority SL packets, relatively high-priority SL channel / signal transmission, and / or relatively high-priority UL channel / signal transmission.

[0180] Figure 11 The process of declaring an RLF by the MAC layer of the TX UE according to an embodiment of the present disclosure is illustrated. Figure 11 The implementation methods can be combined with various implementation methods of this disclosure.

[0181] Reference Figure 11The TX UE may include a MAC layer and a PHY layer. In step S1110, the TX UE may send the PSCCH to the RX UE. In step S1120, the TX UE may send the PSSCH to the RX UE based on the PSCCH. In step S1130, the TX UE may determine the PSFCH resource based on the index of the sub-channel and time slot associated with the PSSCH, and may monitor the PSSCH-related HARQ feedback from the RX UE in the PSFCH resource. In this example, it is assumed that the RX UE did not receive HARQ feedback. In step S1140, the TX UE may retransmit the PSSCH because the monitoring result in S1130 shows that no HARQ feedback was received. At this time, for example, the PHY layer of the TX UE may not pass HARQ feedback to the MAC layer, and the MAC layer of the TX UE may increment the counter associated with DTX by 1. In step S1150, the MAC layer of the TX UE may declare an RLF for SL communication with the RX UE based on the DTX-related counter reaching the maximum threshold.

[0182] Figure 12 The process of initializing the DTX counter by the MAC layer of the TX UE according to an embodiment of the present disclosure is shown. Figure 12 The implementation methods can be combined with various implementation methods of this disclosure.

[0183] Reference Figure 12 The TX UE may include a MAC layer and a PHY layer. In step S1210, the TX UE may send the PSCCH to the RX UE. In step S1220, the TX UE may send the PSSCH to the RX UE based on the PSCCH. In step S1230, ... Figure 11 Unlike S1130, the TX UE cannot perform monitoring of HARQ feedback in the PSFCH resource. For example, the TX UE may not perform monitoring of HARQ feedback due to issues related to half-duplex and / or priority issues between SL and UL. In step S1240, the PHY layer of the TX UE may pass a NACK to the MAC layer based on not performing monitoring of HARQ feedback in the PSFCH resource. In step S1250, the TX UE may perform a retransmission of the PSSCH, and the MAC layer of the TX UE may initialize the counter associated with DTX. According to another embodiment, steps S1240 and S1250 may be omitted. That is, for example, based on the TX UE not performing monitoring of HARQ feedback in the PSFCH resource, the PHY layer of the TX UE may not transmit HARQ feedback to the MAC layer, and the MAC layer may increment the counter associated with DTX by 1.

[0184] Figure 13 The process of a first device performing wireless communication according to an embodiment of the present disclosure is illustrated. Figure 13 The implementation methods can be combined with various implementation methods of this disclosure.

[0185] Reference Figure 13 In step S1310, the first device may send a Physical Secondary Link Control Channel (PSCCH) to the second device. In step S1320, the first device may send a Physical Secondary Link Shared Channel (PSSCH) to the second device based on the PSCCH. In step S1330, the first device may determine the Physical Secondary Link Feedback Channel (PSFCH) resource associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH. Furthermore, in step S1340, the first device may declare a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first and second devices based on the Discontinuous Transmission (DTX) counter reaching a maximum threshold associated with the DTX. For example, the physical layer of the first device may not transmit the HARQ feedback to the media access control (MAC) layer of the first device based on the fact that the first device has not detected a Hybrid Automatic Repeat Request (HARQ) feedback associated with the PSSCH based on the PSFCH resource, and the DTX counter may be incremented by 1 by the MAC layer based on the fact that the HARQ feedback has not been transmitted to the MAC layer of the first device.

[0186] For example, the first device's failure to detect HARQ feedback in the PSFCH resource may be related to half-duplex operation.

[0187] For example, the first device's failure to detect HARQ feedback in the PSFCH resource may be related to prioritization associated with uplink (UL) communication and SL communication.

[0188] For example, if the lack of detected HARQ feedback is due to a failure of the receiving UE's PSSCH decoding or channel state, the DTX counter can be incremented by 1.

[0189] For example, based on i) the first device performing monitoring of HARQ feedback in the PSFCH resource, and ii) the first device being unable to detect HARQ feedback in the PSFCH resource, the reporting related to HARQ feedback to the MAC layer can be omitted.

[0190] For example, based on i) the first device performing monitoring of HARQ feedback in the PSFCH resource, and ii) the first device failing to detect HARQ feedback in the PSFCH resource, the first device may perform a retransmission of the PSSCH.

[0191] For example, the first device may retransmit the PSSCH based on the fact that the first device does not perform monitoring of HARQ feedback in the PSFCH resource.

[0192] For example, based on i) the first device performing monitoring of HARQ feedback in the PSFCH resource, and ii) the first device receiving HARQ feedback based on the monitoring, the first device can transmit a report related to the HARQ feedback to the MAC layer.

[0193] For example, based on i) the first device performing monitoring of HARQ feedback in the PSFCH resource, and ii) the first device receiving HARQ feedback based on monitoring, the first device may perform retransmission of the PSSCH.

[0194] For example, the DTX counter can be initialized based on the retransmission of the PSSCH that is being performed.

[0195] For example, the MAC layer of the first device can receive a NACK from the PHY layer of the first device based on the fact that the priority of the service associated with PSSCH is lower than the priority threshold and no HARQ feedback is detected.

[0196] For example, NACK can be sent based on PUCCH resources.

[0197] For example, the maximum threshold related to DTX can be configured based on the HARQ feedback scheme, and the HARQ feedback scheme can be a NACK-only scheme or an ACK / NACK scheme.

[0198] The above-described embodiments can be applied to various devices described below. For example, the processor 102 of the first device 100 can control the transceiver 106 to transmit the Physical Secondary Link Control Channel (PSCCH) to the second device 200. Furthermore, the processor 102 of the first device 100 can control the transceiver 106 to transmit the Physical Secondary Link Shared Channel (PSSCH) to the second device 200 based on the PSCCH. Furthermore, the processor 102 of the first device 100 can determine the Physical Secondary Link Feedback Channel (PSFCH) resources associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH. Furthermore, the processor 102 of the first device 100 can declare a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first device 100 and the second device 200 based on the Discontinuous Transmission (DTX) counter reaching a maximum threshold associated with DTX. For example, the physical layer of the first device 100 may not transmit the HARQ feedback to the media access control (MAC) layer of the first device 100 based on the fact that the first device 100 has not detected a Hybrid Automatic Repeat Request (HARQ) feedback related to the PSSCH based on the PSFCH resource, and the DTX counter may be incremented by 1 by the MAC layer based on the fact that the HARQ feedback has not been transmitted to the MAC layer of the first device 100.

[0199] According to embodiments of this disclosure, a first apparatus for performing wireless communication can be provided. For example, the first apparatus may include: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: send a Physical Secondary Link Control Channel (PSCCH) to the second device; send a Physical Secondary Link Shared Channel (PSSCH) to the second device based on the PSCCH; determine a Physical Secondary Link Feedback Channel (PSFCH) resource associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH; and declare a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first device and the second device based on the Discontinuous Transmission (DTX) counter reaching a maximum threshold associated with the DTX, wherein the physical layer of the first device may not transmit the HARQ feedback to the media access control (MAC) layer of the first device based on the fact that the first device has not detected a Hybrid Automatic Repeat Request (HARQ) feedback associated with the PSSCH based on the PSFCH resource, and wherein the DTX counter may be incremented by 1 by the MAC layer based on the fact that the HARQ feedback has not been transmitted to the MAC layer of the first device.

[0200] According to embodiments of this disclosure, an apparatus suitable for controlling a first user equipment (UE) can be provided. For example, the apparatus may include: one or more processors; and one or more memories operatively connectable to the one or more processors and storing instructions. For example, the one or more processors may execute the instructions to: send a Physical Secondary Link Control Channel (PSCCH) to a second UE; send a Physical Secondary Link Shared Channel (PSSCH) to the second UE based on the PSCCH; determine a Physical Secondary Link Feedback Channel (PSFCH) resource associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH; and declare a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first UE and the second UE based on the Discontinuous Transmission (DTX) counter reaching a maximum threshold associated with the DTX, wherein the physical layer of the first UE may not transmit the HARQ feedback to the media access control (MAC) layer of the first UE based on the fact that the first UE has not detected a Hybrid Automatic Repeat Request (HARQ) feedback associated with the PSSCH based on the PSFCH resource, and wherein the DTX counter may be incremented by 1 by the MAC layer based on the fact that the HARQ feedback has not been transmitted to the MAC layer of the first UE.

[0201] According to embodiments of this disclosure, a non-transitory computer-readable storage medium storing instructions can be provided. For example, when executed, the instructions can cause a first device to: send a Physical Secondary Link Control Channel (PSCCH) to a second device; send a Physical Secondary Link Shared Channel (PSSCH) to the second device based on the PSCCH; determine a Physical Secondary Link Feedback Channel (PSFCH) resource associated with the PSSCH based on an index of a time slot and an index of a subchannel associated with the PSSCH; and declare a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first device and the second device based on a Discontinuous Transmission (DTX) counter reaching a maximum threshold associated with the DTX. The physical layer of the first device can refrain from transmitting the HARQ feedback to the media access control (MAC) layer of the first device based on the first device not detecting a Hybrid Automatic Repeat Request (HARQ) feedback associated with the PSSCH based on the PSFCH resource, and the DTX counter can be incremented by 1 by the MAC layer based on the HARQ feedback not being transmitted to the MAC layer of the first device.

[0202] Figure 14 The process of a second device performing wireless communication according to an embodiment of the present disclosure is illustrated. Figure 14The implementation methods can be combined with various implementation methods of this disclosure.

[0203] Reference Figure 14 In step S1410, the second device can receive the Physical Secondary Link Control Channel (PSCCH) from the first device. In step S1420, the second device can receive the Physical Secondary Link Shared Channel (PSSCH) from the first device based on the PSCCH. In step S1430, the second device can determine the Physical Secondary Link Feedback Channel (PSFCH) resources associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH. In step S1440, the second device can send a Hybrid Automatic Repeat Request (HARQ) feedback associated with the PSSCH to the first device based on the PSFCH resources. For example, if the Discontinuous Transmission (DTX) counter reaches the maximum threshold associated with DTX, a secondary link (SL) radio link failure (RLF) can be declared for the connection between the first device and the second device. The physical layer of the first device can refuse to transmit the HARQ feedback to the media access control (MAC) layer of the first device based on the fact that the first device has not detected a Hybrid Automatic Repeat Request (HARQ) feedback associated with PSSCH based on PSFCH resources. And based on the fact that the HARQ feedback has not been transmitted to the MAC layer of the first device, the DTX counter can be incremented by 1 by the MAC layer.

[0204] For example, the failure of the first device to detect HARQ feedback in the PSFCH resource may be related to half-duplex, or prioritization related to uplink (UL) communication and SL communication.

[0205] The above-described embodiments can be applied to various devices described below. For example, the processor 202 of the second device 200 can control the transceiver 206 to receive the Physical Secondary Link Control Channel (PSCCH) from the first device 100. Furthermore, the processor 202 of the second device 200 can control the transceiver 206 to receive the Physical Secondary Link Shared Channel (PSSCH) from the first device 100 based on the PSCCH. Furthermore, the processor 202 of the second device 200 can determine the Physical Secondary Link Feedback Channel (PSFCH) resources associated with the PSSCH based on the index of the time slot and the index of the sub-channel associated with the PSSCH. Furthermore, the processor 202 of the second device 200 can control the transceiver 206 to send a Hybrid Automatic Repeat Request (HARQ) feedback associated with the PSSCH to the first device 100 based on the PSSCH resources. For example, if the Discontinuous Transmission (DTX) counter reaches the maximum threshold associated with DTX, a secondary link (SL) radio link failure (RLF) can be declared for the connection between the first device 100 and the second device 200. The physical layer of the first device 100 can refuse to transmit the HARQ feedback to the media access control (MAC) layer of the first device 100 based on the fact that the first device 100 has not detected a Hybrid Automatic Repeat Request (HARQ) feedback associated with PSSCH based on PSFCH resources. And based on the fact that the HARQ feedback has not been transmitted to the MAC layer of the first device 100, the DTX counter can be incremented by 1 by the MAC layer.

[0206] According to embodiments of this disclosure, a second apparatus for performing wireless communication can be proposed. For example, the second apparatus may include: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: receive a Physical Secondary Link Control Channel (PSCCH) from a first device; receive a Physical Secondary Link Shared Channel (PSSCH) from the first device based on the PSCCH; determine a Physical Secondary Link Feedback Channel (PSFCH) resource associated with the PSSCH based on an index of a timeslot and an index of a subchannel associated with the PSSCH; and send a Hybrid Automatic Repeat Request (HARQ) feedback associated with the PSSCH to the first device based on the PSFCH resource, wherein a Secondary Link (SL) Radio Link Failure (RLF) for the connection between the first device and the second device can be declared based on the Discontinuous Transmission (DTX) counter reaching a maximum threshold associated with the DTX, wherein the physical layer of the first device may not transmit the HARQ feedback to the media access control (MAC) layer of the first device based on the first device not detecting the HARQ feedback associated with the PSSCH based on the PSFCH resource, and wherein the DTX counter may be incremented by 1 by the MAC layer based on the HARQ feedback not being transmitted to the MAC layer of the first device.

[0207] For example, the failure of the first device to detect HARQ feedback in the PSFCH resource may be related to the following: half-duplex or priority associated with uplink (UL) and SL communications.

[0208] The following will describe devices to which various embodiments of the present disclosure may be applied.

[0209] The various descriptions, functions, processes, proposals, methods and / or operating procedures described in this document can be applied to, but are not limited to, various fields requiring wireless communication / connectivity between devices (e.g., 5G).

[0210] The following description will be given in more detail with reference to the accompanying drawings. In the following drawings / description, unless otherwise described, the same reference numerals may denote the same or corresponding hardware blocks, software blocks, or functional blocks.

[0211] Figure 15 A communication system (1) according to an embodiment of the present disclosure is shown.

[0212] Reference Figure 15The communication system (1) applying various embodiments of this disclosure includes a wireless device, a base station (BS), and a network. Hereinafter, 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. Wireless devices may include, but are not limited to, robots (100a), vehicles (100b-1, 100b-2), extended reality (XR) devices (100c), handheld devices (100d), home appliances (100e), Internet of Things (IoT) devices (100f), and artificial intelligence (AI) devices / servers (400). For example, a vehicle may include a vehicle with wireless communication capabilities, an autonomous vehicle, and a vehicle capable of performing inter-vehicle communication. Hereinafter, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices can include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and can take the form of head-up displays (HMDs), head-up displays (HUDs) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Handheld devices can include smartphones, smart tablets, wearable devices (e.g., smartwatches or smart glasses) and computers (e.g., laptops). Home appliances can include TVs, refrigerators, and washing machines. IoT devices can include sensors and smart meters. For example, the BS and network can be implemented as wireless devices, and a particular wireless device (200a) can operate as a BS / network node relative to other wireless devices.

[0213] In addition to LTE, NR, and 6G, the wireless communication technologies implemented in the wireless devices 100a to 100f of this disclosure may also include narrowband Internet of Things (IoT) for low-power communication. In this case, for example, NB-IoT technology may be an example of low-power wide-area network (LPWAN) technology and may be implemented as a standard such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the aforementioned names. Alternatively or additionally, the wireless communication technologies implemented in the wireless devices 100a to 100f of this disclosure may perform communication based on LTE-M technology. In this case, as an example, LTE-M technology may be an example of LPWAN and may be referred to by various names including enhanced machine-type communication (eMTC). For example, LTE-M technology may be implemented as at least one of various standards such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE machine-type communication, and / or 7) LTE M, and is not limited to the aforementioned names. Alternatively or additionally, the wireless communication technology implemented in the wireless devices 100a to 100f of this disclosure may include at least one of Bluetooth, Low Power Wide Area Network (LPWAN), and ZigBee, which takes into account low power communication, and is not limited to the names mentioned above. As an example, ZigBee technology may generate personal area networks (PANs) related to low / low power digital communication based on various standards including IEEE 802.15.4, and may be referred to by various names.

[0214] Wireless devices 100a to 100f can connect to network 300 via BS 200. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 400 via network 300. Network 300 can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although wireless devices 100a to 100f can communicate with each other via BS 200 / network 300, wireless devices 100a to 100f can perform direct communication with each other (e.g., secondary link communication) without going through the BS / network. For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0215] Wireless communication / connections 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 via various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, secondary link communication 150b (or D2D communication), or inter-BS communication (e.g., relay, access backhaul integration (IAB)). The wireless devices and BS / wireless devices can transmit / receive radio signals to / from each other via wireless communication / connections 150a and 150b. For example, wireless communication / connections 150a and 150b can transmit / receive signals via various physical channels. For this purpose, at least a portion of various configuration information configuration processes, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation processes for transmitting / receiving radio signals can be performed based on various proposals of this disclosure.

[0216] Figure 16 A wireless device according to an embodiment of the present disclosure is shown.

[0217] Reference Figure 16 The first wireless device (100) and the second wireless device (200) can transmit radio signals via various RATs (e.g., LTE and NR). In this document, {the first wireless device (100) and the second wireless device (200)} can correspond to... Figure 15 {Wireless device (100x) and BS (200)} and / or {Wireless device (100x) and Wireless device (100x)}.

[0218] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processors 102 may control the memories 104 and / or the transceivers 106, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed herein. For example, the processors 102 may process information in the memories 104 to generate a first information / signal, and then transmit a radio signal including the first information / signal via the transceivers 106. The processors 102 may receive a radio signal including a second information / signal via the transceivers 106, and then store the information obtained by processing the second information / signal in the memories 104. The memories 104 may be connected to the processors 102 and may store various information relating to the operation of the processors 102. For example, one or more memories 104 may store software code including commands for performing part or all of the processing controlled by one or more processors 102, or for performing the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed herein. Here, one or more processors 102 and one or more memories 104 may be part of a communication modem / circuit / chip designed to implement 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 via 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 this disclosure, a wireless device may represent a communication modem / circuit / chip.

[0219] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processors 202 may control the memories 204 and / or the transceivers 206, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed herein. For example, the processors 202 may process information in the memories 204 to generate a third message / signal, and subsequently transmit a radio signal including the third message / signal via the transceivers 206. The processors 202 may receive a radio signal including a fourth message / signal via the transceivers 106, and then store the information obtained by processing the fourth message / signal in the memories 204. The memories 204 may be connected to the processors 202 and may store various information relating to the operation of the processors 202. For example, one or more memories 204 may store software code including commands for performing part or all of the processing controlled by one or more processors 202, or for performing 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 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 via 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 this disclosure, a wireless device may represent a communication modem / circuit / chip.

[0220] The hardware elements of wireless devices 100 and 200 will now be described in more detail. One or more protocol layers may be implemented, but are not limited to, by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). One or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operational flows disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flows disclosed 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 descriptions, functions, procedures, proposals, methods, and / or operational flows disclosed in this document, and provide the generated signals to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 and acquire PDUs, SDUs, messages, control information, data, or information in accordance with the descriptions, functions, processes, proposals, methods, and / or operational flows disclosed in this document.

[0221] 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 such firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to perform 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.

[0222] 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, code, 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 drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 may be located internally and / or externally to 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.

[0223] One or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels mentioned in the methods and / or operating procedures 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 descriptions, functions, processes, proposals, methods, and / or operating procedures 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 such 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 such 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 descriptions, functions, processes, proposals, methods, and / or operational procedures 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 for processing using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert the processed user data, control information, radio signals / channels, etc., from baseband signals to RF band signals. For this purpose, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0224] Figure 17 A signal processing circuit for transmitting signals according to an embodiment of the present disclosure is shown.

[0225] Reference Figure 17 The signal processing circuit (1000) may include a scrambler (1010), a modulator (1020), a layer mapper (1030), a pre-encoder (1040), a resource mapper (1050), and a signal generator (1060). It can perform... Figure 17 Operations / functions, but not limited to Figure 16 The processors (102, 202) and / or transceivers (106, 206) can be used. Figure 16Implemented by processors (102, 202) and / or transceivers (106, 206) Figure 17 Hardware components. For example, it can be achieved through... Figure 16 The processors (102, 202) implement boxes 1010 to 1060. Alternatively, they can be implemented using... Figure 16 The processors (102, 202) implement boxes 1010 to 1050, and can be used to... Figure 16 The transceivers (106, 206) are used to implement the frame 1060.

[0226] Can be via Figure 17 The signal processing circuit (1000) converts the codewords into radio signals. In this document, a codeword is a sequence of encoded bits for an information block. The information block may include a transport block (e.g., a UL-SCH transport block, a DL-SCH transport block). Radio signals can be transmitted via various physical channels (e.g., PUSCH and PDSCH).

[0227] Specifically, the codeword can be converted into a scrambled bit sequence by scrambler 1010. The scrambling sequence used for scrambling can be generated based on an initial value, which may include the ID information of the wireless device. The scrambled bit sequence can be modulated into a modulation symbol sequence by 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 layer mapper 1030. The modulation symbols of each transmission layer can be mapped (precoded) to one or more corresponding antenna ports by precoder 1040. The output z of precoder 1040 can be obtained by multiplying the output y of layer mapper 1030 by an N*M precoding matrix W. Here, N is the number of antenna ports, and M is the number of transmission layers. Precoder 1040 can perform precoding after performing transform precoding (e.g., DFT) for the complex modulation symbols. Alternatively, the precoder 1040 can perform precoding without performing transform precoding.

[0228] Resource mapper 1050 maps modulation symbols for each antenna port to time-frequency resources. 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. Signal generator 1060 can generate radio signals from the mapped modulation symbols, and the generated radio signals can be transmitted to other devices via each antenna. For this purpose, 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.

[0229] Can be with Figure 17 The signal processing procedures (1010-1060) are configured in the reverse manner for the signal processing procedures used to receive signals in a wireless device. For example, a wireless device (e.g., Figure 16 The receiver (e.g., 100, 200) can receive radio signals from the outside via the antenna port / transceiver. The received radio signals can be converted into baseband signals using a signal recovery unit. For this purpose, the signal recovery unit 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 signals can be recovered into codewords through a resource demapping process, a post-encoding process, a demodulation processor, and a descrambling process. The codewords can be recovered into the original information blocks through decoding. Therefore, the signal processing circuitry (not illustrated) used for receiving signals may include a signal recovery unit, a resource demapping unit, a post-encoder, a demodulator, a descrambler, and a decoder.

[0230] Figure 18 Another example of a wireless device according to an embodiment of this disclosure is shown. The wireless device can be implemented in various forms depending on the use case / service (see reference). Figure 15 ).

[0231] Reference Figure 18 The wireless devices (100, 200) can correspond to Figure 16 The wireless devices (100, 200) can be configured using various elements, components, units / parts, and / or modules. For example, each of the wireless devices (100, 200) may include a communication unit (110), a control unit (120), a memory 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... Figure 16 One or more processors (102, 202) and / or one or more memories (104, 204). For example, transceiver (114) may include one or more transceivers. Figure 16The device comprises one or more transceivers (106, 206) and / or one or more antennas (108, 208). The control unit (120) is electrically connected to the communication unit (110), memory (130), and add-ons (140), and controls the overall operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on programs / code / commands / information stored in the memory unit (130). The control unit (120) may transmit information stored in the memory unit (130) to an external location (e.g., another communication device) via the communication unit (110) through a wireless / wired interface, or store information received from an external location (e.g., another communication device) via the communication unit (110) through a wireless / wired interface in the memory unit (130).

[0232] The add-on component (140) can be configured in various ways depending on the type of wireless device. For example, the add-on 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 can be implemented in, but is not limited to, the following forms: robot ( Figure 15 100a), vehicles ( Figure 15 100b-1 and 100b-2), XR device ( Figure 15 100c), handheld device ( Figure 15 100d), home appliances ( Figure 15 100e), IoT devices ( Figure 15 100f), digital broadcasting terminals, holographic devices, public safety devices, MTC devices, medical devices, fintech devices (or financial devices), security devices, climate / environmental devices, AI servers / devices ( Figure 15 400), BS ( Figure 15 (e.g., 200), network nodes, etc. Depending on the use case / service, wireless devices can be used in mobile or fixed locations.

[0233] exist Figure 18In the wireless devices (100, 200), all various elements, components, units / parts, and / or modules can be connected to each other via wired interfaces, or at least partially via communication units (110). For example, in each of the wireless devices (100, 200), the control unit (120) and the communication unit (110) can be connected via a wired connection, and the control unit (120) and the first unit (e.g., 130, 140) can be wirelessly connected via the communication unit (110). Each element, component, unit / part, and / or module within the wireless devices (100, 200) may also include one or more elements. For example, the control unit (120) may be constructed using a collection of one or more processors. As an example, the control unit (120) may be constructed using a collection of communication control processors, application processors, electronic control units (ECUs), graphics processing units, and memory control processors. As another example, memory (130) can be constructed using random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), flash memory, volatile memory, non-volatile memory and / or combinations thereof.

[0234] The implementation will be described in detail below with reference to the accompanying drawings. Figure 18 Examples.

[0235] Figure 19 A handheld device according to an embodiment of the present disclosure is illustrated. The handheld device may include a smartphone, smartpad, wearable device (e.g., a smartwatch or smart glasses), or portable computer (e.g., a laptop). The handheld device may be referred to as a mobile station (MS), user terminal (UT), mobile subscriber station (MSS), subscriber station (SS), advanced mobile station (AMS), or wireless terminal (WT).

[0236] Reference Figure 19 The handheld device (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a memory 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 part of the communication unit (110). Blocks 110 to 130 / 140a to 140c correspond to respectively Figure 18 The frame is 110 to 130 / 140.

[0237] Communication unit 110 can send and receive signals (e.g., data signals and control signals) to and from other wireless devices or BSs. Control unit 120 can perform various operations by controlling the constituent elements of handheld device 100. Control unit 120 may include an application processor (AP). Memory unit 130 can store data / parameters / programs / codes / commands required to drive handheld device 100. Memory unit 130 can store input / output data / information. Power supply unit 140a can supply power to handheld device 100 and includes wired / wireless charging circuitry, a battery, etc. Interface unit 140b can support connection of handheld device 100 to other external devices. Interface unit 140b may include various ports for connecting to external devices (e.g., audio I / O ports and video I / O ports). I / O unit 140c can input or output user-input video information / signals, audio information / signals, data, and / or information. I / O unit 140c may include a camera, microphone, user input unit, display unit 140d, speaker, and / or haptic module.

[0238] For example, in the case of data communication, I / O unit 140c can acquire user input information / signals (e.g., touch, text, voice, image, or video), and the acquired information / signals can be stored in memory unit 130. Communication unit 110 can convert the information / signals stored in memory into radio signals and transmit the converted radio signals directly to other wireless devices or to the BS. Communication unit 110 can receive radio signals from other wireless devices or the BS, and then recover the received radio signals into the original information / signals. The recovered information / signals can be stored in memory unit 130 and can be output in various types (e.g., text, voice, image, video, or haptic feedback) through I / O unit 140.

[0239] Figure 20 A vehicle or autonomous vehicle according to an embodiment of this disclosure is shown. The vehicle or autonomous vehicle can be implemented using mobile robots, automobiles, trains, manned / unmanned aerial vehicles (AVs), ships, etc.

[0240] Reference Figure 20 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 part of the communication unit (110). Boxes 110 / 130 / 140a to 140d correspond to respectively Figure 18 The frame size is 110 / 130 / 140.

[0241] Communication unit 110 can send and receive signals (e.g., data signals and control signals) to and from external devices such as other vehicles, BS (e.g., gNB and roadside units), and servers. Control unit 120 can perform various operations by controlling elements of the vehicle or autonomous vehicle 100. Control unit 120 may include electronic control unit (ECU). Drive unit 140a can cause the vehicle or autonomous vehicle 100 to move on the road. Drive unit 140a may include engine, motor, transmission system, wheels, brakes, steering mechanism, etc. Power supply unit 140b can supply power to the vehicle or autonomous vehicle 100 and may include wired / wireless charging circuitry, battery, etc. Sensor unit 140c can acquire vehicle status, external environment information, user information, etc. Sensor unit 140c may include inertial measurement unit (IMU) sensors, collision sensors, wheel sensors, speed sensors, slope sensors, weight sensors, heading sensors, position modules, vehicle forward / reverse sensors, battery sensors, fuel sensors, tire sensors, steering sensors, temperature sensors, humidity sensors, ultrasonic sensors, lighting sensors, pedal position sensors, etc. Autonomous driving unit 140d can implement technologies for maintaining the vehicle's lane, technologies for automatically adjusting speed (e.g., adaptive cruise control), technologies for autonomously driving along a defined path, and technologies for automatically setting a route when a destination is set, etc.

[0242] For example, communication unit 110 can receive map data, traffic information data, etc., from an external server. Autonomous driving unit 140d can generate autonomous driving paths and driving plans from the acquired data. Control unit 120 can control drive unit 140a, enabling the vehicle or autonomous vehicle 100 to move along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, communication unit 110 can periodically or non-periodically acquire the latest traffic information data from an external server and acquire surrounding traffic information data from neighboring vehicles. During autonomous driving, sensor unit 140c can acquire vehicle status and / or surrounding environment information. Autonomous driving unit 140d can update the autonomous driving path and driving plan based on newly acquired data / information. Communication unit 110 can transmit information about vehicle location, autonomous driving path, and / or driving plan to an external server. The external server can predict traffic information data using AI technology, etc., based on information collected from the vehicle or autonomous vehicle, and provide the predicted traffic information data to the vehicle or autonomous vehicle.

[0243] The claims in this specification can be combined in various ways. For example, technical features in the method claims of this specification can be combined to implement or perform in a device, and technical features in the device claims can be combined to implement or perform in a method. Additionally, technical features in one or more method claims and one or more device claims can be combined to implement or perform in a device.

Claims

1. A method of wireless communication performed by a first apparatus, the method comprising: transmitting, to a second apparatus, a physical sidelink control channel, PSCCH; transmitting, to the second apparatus, a physical sidelink shared channel, PSSCH, based on the PSCCH; determining a physical sidelink feedback channel, PSFCH, resource related to the PSSCH based on an index of a slot and an index of a subchannel related to the PSSCH; and declaring a sidelink, SL, radio link failure, RLF, for a connection between the first apparatus and the second apparatus based on a discontinuous transmission, DTX, counter reaching a maximum threshold related to DTX, wherein a physical layer of the first apparatus does not communicate hybrid automatic repeat request, HARQ, feedback related to the PSSCH to a medium access control, MAC, layer of the first apparatus based on the first apparatus not detecting the HARQ feedback related to the PSSCH based on the PSFCH resource, and wherein the DTX counter is incremented by one by the MAC layer based on the HARQ feedback not being communicated to the MAC layer of the first apparatus.

2. The method of claim 1, wherein, the first apparatus not detecting the HARQ feedback in the PSFCH resource is related to half duplex.

3. The method of claim 1, wherein, the first apparatus not detecting the HARQ feedback in the PSFCH resource is related to prioritization related to uplink, UL, communications and SL communications.

4. The method of claim 1, wherein, the DTX counter is incremented by one based on the HARQ feedback not being detected due to PSSCH decoding failure or channel state of a receiving UE.

5. The method of claim 1, wherein, omitting reporting related to the HARQ feedback to the MAC layer based on i) the first apparatus performing monitoring for the HARQ feedback in the PSFCH resource, and ii) the first apparatus failing to detect the HARQ feedback in the PSFCH resource.

6. The method of claim 1, the method further comprising: performing retransmission of the PSSCH based on i) the first apparatus performing monitoring for the HARQ feedback in the PSFCH resource, and ii) the first apparatus failing to detect the HARQ feedback in the PSFCH resource.

7. The method of claim 1, the method further comprising: performing retransmission of the PSSCH based on the first apparatus not performing monitoring for the HARQ feedback in the PSFCH resource.

8. The method of claim 1, the method further comprising: communicating reporting related to the HARQ feedback to the MAC layer based on i) the first apparatus performing monitoring for the HARQ feedback in the PSFCH resource, and ii) the first apparatus receiving the HARQ feedback based on the monitoring.

9. The method of claim 1, the method further comprising: performing a retransmission of the PSSCH based on i) the first apparatus performing monitoring for the HARQ feedback in the PSFCH resource, and ii) the first apparatus receiving the HARQ feedback based on the monitoring.

10. The method of claim 9, wherein, the retransmission of the PSSCH is performed based on initializing the DTX counter.

11. The method of claim 1, wherein, the MAC layer of the first apparatus receives a NACK from the PHY layer of the first apparatus based on a priority of a service related to the PSSCH being lower than a priority threshold and no detection of the HARQ feedback.

12. The method of claim 1, wherein, the NACK is transmitted based on a PUCCH resource.

13. The method of claim 1, wherein, the maximum threshold related to the DTX is configured based on a HARQ feedback scheme, and wherein the HARQ feedback scheme is a NACK only scheme or an ACK / NACK scheme.

14. A first apparatus for performing wireless communication, the first apparatus comprising: 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, wherein the one or more processors execute the instructions to: transmit, to a second apparatus, a physical sidelink control channel, PSCCH, transmit, to the second apparatus, a physical sidelink shared channel, PSSCH, based on the PSCCH; determine a physical sidelink feedback channel, PSFCH, resource related to the PSSCH based on an index of a slot and an index of a subchannel related to the PSSCH; and declare a sidelink, SL, radio link failure, RLF, for a connection between the first apparatus and the second apparatus based on a discontinuous transmission, DTX, counter reaching a maximum threshold related to DTX, wherein a physical layer of the first apparatus does not communicate a hybrid automatic repeat request, HARQ, feedback related to the PSSCH to a medium access control, MAC, layer of the first apparatus based on the first apparatus not detecting the HARQ feedback related to the PSSCH based on the PSFCH resource, and wherein the DTX counter is incremented by one by the MAC layer based on the HARQ feedback not being communicated to the MAC layer of the first apparatus.

15. The first apparatus of claim 14, wherein, the first apparatus is a first UE, and wherein the first UE is controlled by an apparatus adapted to control the first apparatus.

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