Method and apparatus for performing sidelink communications over unlicensed spectrum

Abstract

A first wireless user device (WUE) operating in a sidelink unlicensed band in a wireless communication system includes at least one antenna for transmitting and receiving one or more wireless signals, at least one processor, and a memory for storing instructions for the wireless user device when executed by the at least one processor, wherein operations of the wireless user device include: transmitting SL data to a second wireless user device (WUE) via a PSFCH; receiving SL HARQ-ACK information for the PSSCH based on a PSFCH ROC associated with the PSSCH; generating SL HARQ feedback information based on the SL HARQ-ACK information and reporting it to a base station; and wherein the PSSCH can be associated with a PSFCH ROC set including a plurality of PSFCH ROCs based on the unlicensed band.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for reporting sidelink (SL) hybrid automatic repeat request (HARQ) information to a base station via an uplink in a sidelink unlicensed (SL-U) band in a wireless communication system. [Background technology]

[0002] The International Telecommunication Union (ITU) is developing the International Mobile Telecommunication (IMT) framework and standards, and recently discussions for fifth-generation (5G) communications have been underway through a program called "IMT for 2020 and beyond."

[0003] To meet the requirements set out in "IMT for 2020 and beyond," the 3GPP (registered trademark) 3rd Generation Partnership Project (NR) New Radio (NR) system is currently discussing the support of various numerologies for time-frequency resource unit standards, taking into account various scenarios, service requirements, potential system compatibility, etc.

[0004] In addition, discussions are underway on how to support seamless communication services at the service level for mobile terminals (e.g., vehicles, trains, ship-type terminals, and personally owned smartphones) using not only terrestrial networks (TR) but also non-terrestrial networks (NON) in new communication systems. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention relates to a method and apparatus for operating a terminal in SL-U of a wireless communication system.

[0006] The present invention relates to a method and apparatus for a terminal to report SL HARQ feedback information to a base station through an uplink in SL-U.

[0007] The present invention relates to a method and apparatus for determining SL HARQ feedback information that a terminal reports to a base station in SL-U. [Means for solving the problem]

[0008] According to one embodiment, a first wireless user device (UE) operating in a sidelink unlicensed band in a wireless communication system includes at least one antenna for transmitting and receiving one or more wireless signals, at least one processor, and a memory for storing instructions for the wireless user device, when executed by the at least one processor, wherein operations of the wireless user device include: transmitting sidelink (SL) data to a second wireless user device via a physical sidelink shared channel (PSSCH); receiving SL hybrid automatic repeat request (HARQ)-ACK information for the PSSCH based on a physical sidelink feedback channel (PSFCH) reception occasion (ROC) associated with the PSSCH; generating and reporting SL HARQ feedback information to a base station based on the SL HARQ-ACK information; and, based on the unlicensed band, the PSSCH can be associated with a PSFCH ROC set including a plurality of PSFCH ROCs.

[0009] Additionally, in accordance with one embodiment, the first wireless user equipment may perform SL communications with the second wireless user equipment based on SL unicast.

[0010] Furthermore, according to one embodiment, the SL HARQ-ACK information may be determined based on a last PSFCH ROC set in the time domain among at least one PSFCH ROC set associated with the PSSCH, and the SL HARQ-ACK information may be generated based on a last received PSFCH among at least one PSFCH received in the last PSFCH ROC set in the time domain.

[0011] Furthermore, according to an embodiment, if the PSFCH cannot be received in the last PSFCH ROC set in the time domain among at least one PSFCH ROC set associated with the PSSCH, and the PSFCH is not received in a PSFCH ROC set before the last PSFCH ROC set, the SL HARQ-ACK information may be generated as a NACK.

[0012] Furthermore, according to an embodiment, when at least one PSFCH ROC set associated with a PSSCH is located in different resource block sets (RBSs) and there are multiple last PSFCH ROC sets, if multiple PSFCHs are received in the multiple last PSFCH ROC sets, the SL HARQ feedback information may be generated based on PSFCH information with the lowest RBS index among the multiple received PSFCHs.

[0013] Furthermore, according to an embodiment, when a first wireless user equipment performs SL communication in which the first wireless user equipment receives SL HARQ-ACK information from all second wireless user equipments in a group in an SL groupcast manner, the SL HARQ feedback information may be determined as an ACK when the first wireless user equipment receives SL HARQ-ACK information for the SL groupcast PSSCH transmission in at least one PSFCH ROC among a plurality of PSFCH ROCs in the PSFCH ROC set.

[0014] Furthermore, according to an embodiment, when a first wireless user equipment performs SL communication in a manner of receiving SL HARQ-ACK information from a second wireless user equipment that transmits a NACK within a group in an SL groupcast manner, the SL HARQ feedback information may be determined in an ACK based on whether or not a PSFCH is received on a PSFCH ROC in all PSFCH ROC sets corresponding to the PSSCH transmission. [Effects of the Invention]

[0015] According to the present disclosure, a method for operating a terminal in the SL-U of a wireless communication system can be provided.

[0016] According to the present disclosure, a method can be provided in SL-U where a terminal reports SL HARQ feedback information to a base station via an uplink.

[0017] According to the present disclosure, it is possible to provide a method for determining SL HARQ feedback information that a terminal reports to a base station in SL-U.

[0018] The present disclosure is not limited to the above-mentioned effects, and other effects not mentioned herein will be clearly understood by those skilled in the art to which the present disclosure pertains from the following description. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram for explaining an NR frame structure to which the present disclosure can be applied. [Figure 2] FIG. 2 is a diagram illustrating an NR resource structure to which the present disclosure may be applied. [Figure 3] FIG. 3 is a diagram illustrating an NR sidelink slot structure to which the present disclosure can be applied. [Figure 4] FIG. 4 is a diagram illustrating NR sidelink frequencies to which the present disclosure can be applied. [Figure 5] FIG. 5 is a diagram illustrating an NR sidelink resource pool configuration to which the present disclosure can be applied. [Figure 6] FIG. 6 is a diagram illustrating unlicensed bands by region for NR sidelink communication to which the present disclosure can be applied. [Figure 7] FIG. 7 is a diagram illustrating 5 GHz unlicensed band usage to which the present disclosure may be applied. [Figure 8] FIG. 8 illustrates a method for increasing bandwidth taking into account PSD limitations to which the present disclosure may be applied. [Figure 9] FIG. 9 is a diagram showing a method for setting a guard band in consideration of a shared band within an intra-cell to which the present disclosure can be applied. [Figure 10] FIG. 10 is a diagram illustrating an interlace-based RB resource allocation method to which the present disclosure can be applied. [Figure 11] FIG. 11 is a diagram illustrating a method for performing a listen before talk (LBT) procedure in an unlicensed spectrum to which the present disclosure may be applied. [Figure 12] FIG. 12 is a diagram illustrating COT sharing and discovery burst transmission to which the present disclosure can be applied. [Figure 13] FIG. 13 is a diagram illustrating a method for applying a CP extension to an uplink when performing COT sharing between a downlink and an uplink to which the present disclosure may be applied. [Figure 14] FIG. 14 is a diagram illustrating a semi-static channel connection procedure to which the present disclosure can be applied. [Figure 15] FIG. 15 is a diagram illustrating a method for performing channel occupation to which the present disclosure may be applied. [Figure 16] FIG. 16 illustrates a method for configuring RBS with BWP and resource pool in a sidelink unlicensed band to which the present disclosure may be applied. [Figure 17] FIG. 17 is a diagram illustrating a method for configuring a resource pool for a sidelink unlicensed band to which the present disclosure can be applied. [Figure 18] FIG. 18 illustrates a frequency resource-based sidelink unlicensed band resource pool configuration using interlace allocation to which the present disclosure can be applied. [Figure 19]FIG. 19 illustrates a sidelink unlicensed band resource pool configuration method to which the present disclosure can be applied. [Figure 20] FIG. 20 is a diagram illustrating the relationship between the PSSCH and the PSFCH ROC set to which the present disclosure can be applied. [Figure 21] FIG. 21 illustrates a method for generating SL HARQ-ACK information using a PSFCH ROC set in a single RBS-based unicast environment to which the present disclosure may be applied. [Figure 22] FIG. 22 illustrates a method for generating SL HARQ-ACK information using a PSFCH ROC set in multi-RBS based unicast to which the present disclosure can be applied. [Figure 23] FIG. 23 is a diagram illustrating a method for generating and reporting SL HARQ feedback information to a base station to which the present disclosure can be applied. [Figure 24] FIG. 24 is a diagram showing a base station apparatus and a terminal apparatus to which the present disclosure can be applied. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present disclosure will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein.

[0021] In describing embodiments of the present disclosure, if it is determined that a detailed description of a known configuration or function would obscure the gist of the present disclosure, the detailed description will be omitted. In addition, in the drawings, parts that are not related to the description of the present disclosure will be omitted, and similar parts will be designated by similar reference numerals.

[0022] In this disclosure, when a component is said to be "coupled," "coupled," or "connected" to another component, this refers not only to a direct connection, but also to an indirect connection where there is another component between them. Furthermore, when a component is said to "include" or "have" another component, this does not exclude the other component, but means that the component may further include the other component, unless otherwise specified.

[0023] In this disclosure, terms such as first and second are used only to distinguish one component from another, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0024] In this disclosure, components that are distinguished from one another are used to clearly describe the characteristics of each component and do not necessarily mean that the components are separate. That is, multiple components may be integrated into a single hardware or software unit, or a single component may be distributed into multiple hardware or software units. Therefore, even if not otherwise specified, such integrated or distributed embodiments are also included within the scope of this disclosure.

[0025] In this disclosure, the components described in various embodiments are not necessarily essential components, and some may be optional components. Therefore, an embodiment consisting of a subset of the components described in one embodiment is also included in the scope of this disclosure. Note that an embodiment including other components in addition to the components described in various embodiments is also included in the scope of this disclosure.

[0026] The present disclosure describes a wireless communication network, and operations performed in the wireless communication network may be performed in a process of controlling the network and transmitting or receiving signals by a system (e.g., a base station) that manages the wireless communication network, or in a process of transmitting or receiving signals by a terminal coupled to the wireless network.

[0027] It is apparent that various operations performed for communication with a terminal in a network consisting of multiple network nodes including a base station may be performed by the base station or other network nodes other than the base station. The term "base station (BS)" may be replaced with terms such as fixed station, Node B, eNodeB (eNB), ng-eNB, gNodeB (gNB), access point (AP), etc. Furthermore, the term "terminal" may be replaced with terms such as user equipment (UE), mobile station (MS), mobile subscriber station (MSS), subscriber station (SS), non-AP station (non-AP STA), etc.

[0028] In this disclosure, transmitting or receiving a channel includes transmitting or receiving information or signals through the channel. For example, transmitting a control channel means transmitting control information or signals through the control channel. Similarly, transmitting a data channel means transmitting data information or signals through the data channel.

[0029] In the following description, the term NR (New Radio) system is used to distinguish the system to which various examples of the present disclosure are applied from existing systems, but the scope of the present disclosure is not limited by these terms.

[0030] The NR system supports various subcarrier spacings (SCS) taking into account various scenarios, service requirements, and potential system compatibility. The NR system can also support the transmission of physical signals / channels through multiple beams to overcome adverse channel conditions such as high path loss, phase noise, and frequency offset that occur at high carrier frequencies. This allows the NR system to support applications such as enhanced Mobile Broadband (eMBB), massive Machine Type Communications (mMTC) / ultra Machine Type Communications (uMTC), and Ultra Reliable and Low Latency Communications (URLLC).

[0031] Hereinafter, 5G mobile communication technology may be defined to include not only the NR system but also the existing LTE-A (Long Term Evolution-Advanced) and LTE (Long Term Evolution) systems. That is, 5G communication may include not only the newly defined NR system but also technologies that operate in consideration of backward compatibility with previous systems. Therefore, the 5G mobile communication described below may include technologies that operate based on the NR system and technologies that operate based on previous systems (e.g., LTE-A, LTE), and is not limited to a specific system.

[0032] First, a brief description will be given of the physical resource structure of the NR system to which the present invention is applied.

[0033] FIG. 1 is a diagram for explaining an NR frame structure to which the present disclosure can be applied.

[0034] The basic unit of time domain in NR is T c =1 / (Δf max N f ) and Δf max =480 10 3 and N f = 4096, whereas the time domain base unit in LTE is Ts = 1 / (Δf ref N f,ref ) and Δf ref =15 10 3 and N f,ref = 2048. The constant for the multiple relationship between the base unit of NR time and the base unit of LTE time is κ = T s / T c =64.

[0035] Referring to FIG. 1, the time structure of a frame for downlink / uplink (DL / UL) transmission is T f =(Δf max N f / 100)·T s = 10 ms, where one frame is T sf =(Δf max N f / 1000)·T s The number of consecutive OFDM symbols in each subframe is N subframe,u symb =N slot symb N subframe,u slot Also, each frame can be divided into two half frames of the same size, with half frame 1 consisting of subframes 0 to 4 and half frame 2 consisting of subframes 5 to 9.

[0036] N TA denotes the timing advance (TA) between the downlink (DL) and the uplink (UL), where the transmission timing of the uplink transmission frame i is determined based on the downlink reception timing at the terminal according to the following Equation 1:

[0037]

number

[0038] where N TA,offset is the TA offset value that occurs due to differences in duplex modes. TA,offset has a value of 0, but in TDD (Time Division Duplex), N is set to N in consideration of the margin for DL-UL switching time. TA,offset For example, in TDD (Time Division Duplex) in FR1 (Frequency Range 1), which is a frequency below 6 GHz, N TA,offset can be 39936Tc or 25600Tc. 39936Tc is 20.327μs, and 25600Tc is 13.030μs. Also, in FR2 (Frequency Range 2), which is a millimeter wave (mmWave) frequency, N TA,offset can be 13792Tc, where 39936Tc is 7.020μs.

[0039] FIG. 2 is a diagram illustrating an NR resource structure to which the present disclosure may be applied.

[0040] The resource elements (REs) in the resource grid can be indexed by each subcarrier spacing, where one resource grid can be generated for each antenna port and each subcarrier spacing, and uplink and downlink transmission and reception can be performed based on the resource grid.

[0041] In the frequency domain, one resource block (RB) consists of 12 REs, and an index (nPRB ) can be configured. The index for the RB can be used within a specific frequency band or system bandwidth. The index for the RB can be defined as in Equation 2 below. Here, N RB sc denotes the number of subcarriers per RB, and k denotes the subcarrier index.

[0042]

number

[0043] Various neural networks can be configured to meet the various services and requirements of the NR system. For example, an LTE / LTE-A system can support one subcarrier spacing (SCS), while an NR system can support multiple SCSs.

[0044] New pneumatics for NR systems supporting multiple SCSs can operate in frequency ranges or carriers such as below 3 GHz, 3 GHz to 6 GHz, 6 GHz to 52.6 GHz, or above 52.6 GHz, solving the problem of not being able to use wide bandwidths in frequency ranges or carriers such as 700 MHz or 2 GHz.

[0045] Table 1 below shows examples of pneumoradio supported by the NR system.

[0046] [Table 1]

[0047] Referring to Table 1, the neural network parameters can be defined based on the subcarrier spacing (SCS), cyclic prefix (CP) length, and number of OFDM symbols per slot used in an Orthogonal Frequency Division Multiplexing (OFDM) system. These values ​​can be provided to the UE through upper layer parameters DL-BWP-mu and DL-BWP-cp for the downlink and through upper layer parameters UL-BWP-mu and UL-BWP-cp for the uplink.

[0048] In Table 1, when the subcarrier spacing setting index (u) is 2, the subcarrier spacing (Δf) is 60 kHz, and normal CP and extended CP can be applied. In other cases, only normal CP can be applied.

[0049] A normal slot can be defined as a basic time unit used to transmit one piece of data and control information in an NR system. The length of a normal slot can be basically set to 14 OFDM symbols. Furthermore, unlike a slot, a subframe has an absolute time length corresponding to 1 ms in an NR system and can be used as a reference time for the length of other time intervals. Here, for coexistence or backward compatibility between LTE and NR systems, a time interval similar to an LTE subframe may be required in the NR standard.

[0050] For example, in LTE, data may be transmitted based on a transmission time interval (TTI), which is a unit of time, and the TTI may be set in units of one or more subframes. Here, in LTE, one subframe may be set to 1 ms and may include 14 OFDM symbols (or 12 OFDM symbols).

[0051] Furthermore, non-slots can be defined in NR. A non-slot may refer to a slot having a number of symbols at least one smaller than that of a normal slot. For example, when providing low latency, such as in a URLLC service, the latency can be reduced by using a non-slot having a number of symbols smaller than that of a normal slot. Here, the number of OFDM symbols included in a non-slot can be determined taking into account the frequency range. For example, in a frequency range of 6 GHz or higher, a non-slot having a length of one OFDM symbol can be considered. As a further example, the number of OFDM symbols defining a non-slot can include at least two OFDM symbols. Here, the range of the number of OFDM symbols included in a non-slot can be set as the length of a mini-slot up to a predetermined length (e.g., the normal slot length minus 1). However, as a non-slot standard, the number of OFDM symbols may be limited to, but not limited to, 2, 4, or 7 symbols.

[0052] For example, in unlicensed bands below 6 GHz, subcarrier spacing where u is 1 and 2 can be used, and in unlicensed bands above 6 GHz, subcarrier spacing where u is 3 and 4 can be used. For example, when u is 4, it can be used for SSB (Synchronization Signal Block).

[0053] [Table 2]

[0054] Table 2 shows the number of OFDM symbols per slot (N) for normal CP, depending on the subcarrier spacing setting (u). slot symb ), number of slots per frame (N frame,u slot ), the number of slots per subframe (N subframe,u slot) Table 2 shows the above values ​​based on a normal slot having 14 OFDM symbols.

[0055] [Table 3]

[0056] Table 3 shows the number of slots per frame and the number of slots per subframe when extended CP is applied (i.e., when u is 2 and the subcarrier spacing is 60 kHz), based on a normal slot with 12 OFDM symbols per slot.

[0057] As mentioned above, one subframe may correspond to 1 ms on the time axis. Furthermore, one slot may correspond to 14 symbols on the time axis. For example, one slot may correspond to 7 symbols on the time axis. Therefore, the number of slots and symbols that can be considered within 10 ms, which corresponds to one radio frame, can be set differently. Table 4 shows the number of slots and symbols according to each SCS. In Table 4, the 480 kHz SCS may not be considered, but is not limited to these examples.

[0058] [Table 4]

[0059] V2X services (e.g., LTE Rel-14 V2X) can support basic requirements for V2X services. The requirements are primarily designed with road safety services in mind. Here, V2X User Equipment (UE) can exchange status information with each other through sidelink. Furthermore, V2X UE can exchange information with infrastructure nodes and / or pedestrians.

[0060] V2X services (e.g., LTE Rel-15) can support at least one of carrier aggregation, high order modulation, latency reduction, transmit diversity, and sTTI (Transmission Time Interval) in the sidelink. To this end, new features can be applied to V2X communication. Specifically, V2X UEs can operate while taking into account coexistence with other V2X UEs. For example, V2X UEs can use the same resource pool as other V2X UEs.

[0061] As an example, considering use cases for supporting V2X services in SA (System Aspect) 1, technical features can be classified into four categories as shown in Table 5 below, but are not limited to these. In Table 5, Vehicle Platooning can be a technology in which multiple vehicles dynamically form a group and operate in a similar manner. Extended Sensors can be a technology that collects and exchanges data obtained from sensors or video footage. Advanced Driving can be a technology in which vehicles drive based on full automation or semi-automation. Remote Driving can be a technology that provides technology and applications for remote control of vehicles, and more specific details of the above can be seen in Table 5 below.

[0062] [Table 5-1] [Table 5-2]

[0063] Furthermore, SA1 is an eV2X (enhanced V2X) support technology for supporting V2X services and can support cases where it operates in various systems (e.g., LTE, NR). As an example, a case can be considered in which the NR V2X system is a first V2X system and the LTE V2X system is a second V2X system. That is, the NR V2X system and the LTE V2X system can be different V2X systems.

[0064] Hereinafter, a method for achieving low latency and high reliability required for an NR sidelink will be described based on an NR V2X system. However, the same or similar configuration may be extended and applied to an LTE V2X system, and the present invention is not limited to the following embodiments. That is, the present invention may be applied to parts that are interoperable with an LTE V2X system.

[0065] Here, NR V2X capability is not necessarily limited to supporting only V2X services, and may optionally support the use of a certain V2X RAT.

[0066] Additionally, NR V2X services can additionally consider new service requirements for public safety and commercial use cases. For example, use cases may include, but are not limited to, at least one of more advanced V2X services, public safety services, NCIS (Network Controlled Interactive Service), MONASTERYEND (Gap Analysis for Railways), REFEC (Enhanced Relays for Energy eFficiency and Extensive Coverage), and AVPROD (Audio-Visual Service Production).

[0067] For the NR V2X, physical channels, signals, a basic slot structure, and physical resources can be configured. Here, the NR Physical Sidelink Shared Channel (NR PSSCH) can be a physical layer NR Sidelink (SL) data channel. V2X terminals can exchange data and control information (e.g., 2nd SCI, CSI) through the NR PSSCH. The NR Physical Sidelink Control Channel (NR PSCCH) is a physical layer NR SL control channel. The NR PSCCH is a channel for transmitting control information (1st SCI, Sidelink Control Information) including scheduling information for the NR SL data channel and a 2nd SCI indication. That is, a V2X terminal can transmit control information for sidelink data communication to another V2X terminal through the PSCCH. The NR Physical Sidelink Feedback Channel (NR PSFCH) is a channel for transmitting physical layer NR Hybrid Automatic Repeat Request (HARQ) feedback information and for transmitting HARQ-ACK feedback information corresponding to the NR SL data channel (i.e., PSSCH). After transmitting data to another V2X terminal, a V2X terminal can receive HARQ feedback information for the data via the NR PSFCH. The NR Sidelink Synchronization Signal / Physical Sidelink Broadcast Channel block (SLSS / PSBCH block) is a channel block in which an NR sidelink synchronization signal and a broadcast channel are transmitted over a continuous time period in the physical layer. Here, the SLSS / PSBCH block may be transmitted periodically based on a set of one or more block indexes to support beam-based transmission in the NR frequency band.The synchronization signal consists of a Primary Sidelink Synchronization Signal (PSSS) and a Secondary Sidelink Synchronization Signal (SSSS). The synchronization signal is generated in a sequence based on at least one SLSSID value. The NR Physical Sidelink Broadcast Channel (PSBCH) is a channel that carries system information required for V2X sidelink communication. The NR PSBCH is transmitted together with the SLSS and is periodically transmitted in the form of an aggregate of the SLSS / PSBCH block index to support beam-based transmission.

[0068] In addition, a physical sidelink control channel (PSCCH) and a physical sidelink shared channel (PSSCH) can be defined based on NR V2X. A terminal can transmit sidelink control information (SCI) to another terminal through the PSCCH. Here, a transmitting terminal can transmit a primary SCI (1st SCI, SCI format 1-A) to a receiving terminal through the PSSCH. In this case, the primary SCI can be used to schedule the PSSCH and the secondary SCI (2nd SCI) within the PSSCH, and the primary SCI can include at least one of priority information, time / frequency resource allocation information, resource reservation information, Demodulation Reference Signal (DMRS) pattern information, secondary SCI format indication information, beta-offset indicator information as a parameter for the secondary SCI and PSSCH rate matching operation, DMRS port number information, MCS (Modulation Coding Scheme) information, additional MCS table indicator information (e.g., indicating one of 64QAM, 256QAM, or URLLC MCS tables), PSFCH overhead indication information (a parameter for the 2nd SCI and PSSCH rate matching operation), and reserved bits.

[0069] FIG. 3 is a diagram illustrating an NR sidelink slot structure to which the present disclosure can be applied.

[0070] Referring to FIG. 3, one sidelink slot (SL slot) includes one automatic gain control (AGC) symbol. One SL slot also includes one transmit-receive (Tx-Rx) switching symbol. In one SL slot, the PSSCH, which is a channel for transmitting data, is transmitted through one or more subchannels (e.g., two subchannels in the case of FIG. 3). In addition, in the time domain, the remaining orthogonal frequency division multiplexing (OFDM) symbols, excluding the AGC symbol and the Tx-Rx switching symbol, may transmit the PSCCH (1st SCI), the secondary SCI, the PSSCH (Data), and a demodulation RS (DMRS) for demodulation. Specifically, the positions of the PSCCH (1st SCI), the secondary SCI, the PSSCH (Data), and the DMRS (Demodulation RS) for demodulation are as shown in FIG. 3, but are not limited thereto. For example, in Fig. 3, the first subchannel has a PSCCH and a secondary SCI, and the PSSCH and DMRS can be allocated taking this into consideration. As another example, the second subchannel in Fig. 3 is a subchannel without a PSCCH or a secondary SCI, and the PSSCH and DMRS can be allocated as shown in Fig. 3.

[0071] Here, the number of OFDMs for the PSSCH DMRS can be set to one or more depending on the channel environment of the terminal through higher layer configuration. The PSCCH (1st SCI) is decoded and received using the DMRS of the PSCCH (i.e., the PSCCH DMRS) and is transmitted by being evenly allocated to every four resource elements within one resource block (RB). On the other hand, the 2nd SCI is decoded using the PSSCH DMRS.

[0072] For example, one resource pool related to the NR sidelink can support all of frequency division multiplexing (FDM), time division multiplexing (TDM), and spatial division multiplexing (SDM). That is, each resource in one resource pool can be divided and used based on frequency, time, and space, thereby improving resource efficiency.

[0073] 4 is a diagram illustrating NR sidelink frequencies to which the present disclosure can be applied. For example, the NR sidelink can operate based on at least one of FR1 (Frequency Range 1, sub 6 GHz) and FR2 (Frequency Range 2, i.e., up to 52.6 GHz), unlicensed ITS bands, and licensed bands. As a specific example, referring to FIG. 4, 5,855 to 5,925 MHz can be allocated for ITS services (technology neutral manner).

[0074] Furthermore, NR V2X Quality of Service (QoS) requirements can be considered. That is, as requirements for NR V2X services, delay, reliability, and data rate must meet certain conditions. Here, the requirements can be set as shown in Table 6 below, and Table 7 can be a table showing PC5 QoS for NR V2X.

[0075] Here, to meet QoS requirements, access stratum (AS)-level QoS management may be necessary. For this purpose, HARQ and CSI feedback associated with link adaptation may be required. Furthermore, each NR V2X UE may have a different maximum bandwidth capability. In consideration of the above, NR V2X UEs may exchange AS-level information including at least one of UE capability, QoS-related information, radio bearer configuration, and physical layer configuration.

[0076] [Table 6]

[0077] [Table 7-1] [Table 7-2] [Table 7-3]

[0078] Next, the sidelink HARQ procedure will be described. Whether a V2X UE reports HARQ feedback is indicated by higher layer (e.g., RRC) configuration and SCI signaling (e.g., secondary SCI). For example, when a V2X UE performs communication based on groupcast, it can determine whether to report HARQ feedback based on the distance between the transmitting UE and the receiving UE.

[0079] When a V2X terminal performs unicast and / or groupcast, it may enable or disable sidelink HARQ feedback, where the enable / disable of HARQ feedback may be determined based on at least one of channel conditions (e.g., RSRP), the distance between the transmitting terminal and the receiving terminal, and QoS requirements.

[0080] In the case of groupcast, whether to transmit HARQ feedback can be determined depending on the physical distance between the transmitting terminal and the receiving terminal. Here, when HARQ feedback is performed based on groupcast, the receiving terminal can operate to feed back a negative acknowledgment only when PSSCH decoding fails. This can be the operation of option 1. On the other hand, when HARQ feedback is performed based on groupcast, the receiving terminal can operate to feed back a positive or negative acknowledgment depending on whether PSSCH decoding is successful, which can be the operation of option 2. In the operation of option 1, which feeds back only a negative acknowledgment to the HARQ NACK based on groupcast, feedback for the PSSCH can be performed if the physical distance between the transmitting terminal and the receiving terminal is smaller than or equal to the communication range requirement. On the other hand, if the physical distance between the transmitting terminal and the receiving terminal is larger than the communication range requirement, the V2X terminal does not need to feed back PSSCH.

[0081] At this time, the location of the transmitting terminal is indicated to the receiving terminal through the SCI associated with the PSSCH. The receiving terminal can estimate the distance to the transmitting terminal based on the information included in the SCI and its own location information and operate as described above.

[0082] In addition, when performing unicast communication based on V2X, the case where sidelink HARQ feedback is enabled can be taken into consideration. The receiving terminal can generate and transmit HARQ ACK / NACK for PSSCH based on whether the corresponding TB (Transport Block) has been successfully decoded.

[0083] Next, the NR sidelink resource allocation mode includes a mode in which the base station schedules sidelink transmission resources. Here, the mode in which the base station schedules sidelink transmission resources may be Mode 1. For example, when a V2X terminal is located within the base station coverage, the V2X terminal may receive sidelink resource information from the base station based on Mode 1. On the other hand, there is also a mode in which the V2X terminal directly determines resources for sidelink transmission from sidelink resources configured by the base station / network or pre-configured sidelink resources. Here, the mode in which the terminal directly determines sidelink transmission resources may be Mode 2.

[0084] Also, the numerology and waveform for the sidelink may be considered, and may be as shown in Table 8 below. Specifically, in relation to the PSSCH / PSCCH and PSFCH in the sidelink, the SCS and CP lengths supported by each of FR1 and FR2 may be as shown in Table 8 below. Here, the waveform may not support DFT-S-OFDM and may support only OFDM, but is not limited thereto. A sidelink-synchronization signal block (SL-SSB) may be defined independently for each frequency range, which may be similar to NR-Uu.

[0085] [Table 8]

[0086] FIG. 5 is a diagram illustrating an NR sidelink resource pool configuration to which the present disclosure can be applied. Referring to FIG. 5, a resource pool may refer to time and frequency resources used for sidelink transmission and reception. As an example, at least one resource pool may be configured within one SL BWP within one carrier. Here, the resources of the resource pool may be configured based on time resources in units of slot sets and frequency resources in units of consecutive subchannel sets. Furthermore, the resource pool may be configured separately for transmission and reception.

[0087] More specifically, the time resource for resource pool configuration provided in the NR sidelink is the time period of the resource pool, a set of sidelink slots (sl-TimeResource(length=L bitmap)), the first symbol for a set of consecutive symbols within one slot, and / or the number of consecutive symbols may be configured. The frequency resource may be configured as at least one of the bandwidth of one subchannel (e.g., sl-SubchannelSize={10, 15, 20, 25, 50, 75, and 100} RBs), the total bandwidth of a resource pool indicated by the number of consecutive subchannels (a set of consecutive subchannels (e.g., sl-NumSubchannel={1 to 27}), and the frequency domain position of the first subchannel of the resource pool (sl-StartRBsubchannel={0 to 265}). For example, resources in the time domain and the frequency domain may be configured based on higher layer parameters. In FIG. 5, the frequency resource corresponding to the excluded resource block (RB) may refer to some RBs remaining when the total available RB resources do not exactly match the subchannel size (i.e., the number of RBs does not equal one subchannel). In this case, the resource may not be used in the NR sidelink. Also, for example, reserved slots (reserved slots) may be configured. The sl-slot) can refer to the remaining slots when the length of the bitmap on the time resource (e.g., sl-TimeResource) is not a multiple of the length, and does not need to be used as an NR sidelink resource.

[0088] Next, a case where an unlicensed spectrum is used for communication between a base station and a terminal may be considered. For example, a communication scheme based on an unlicensed spectrum may occupy a channel through contention and perform communication based on the occupied channel. Communication based on an unlicensed spectrum may also be performed between a base station and a terminal. Hereinafter, an operation based on a case where an unlicensed spectrum is used for sidelink communication will be described. That is, an unlicensed spectrum may also be used in sidelink communication, which is communication between terminals. Furthermore, a sidelink resource pool needs to be configured taking into account the use of a sidelink unlicensed spectrum. More specifically, sidelink communication may be performed based on a resource pool, and if communication is performed through an unlicensed spectrum, the resource pool configuration needs to be different.

[0089] For example, the resource pool for sidelink communication may be configured on a slot-by-slot basis to determine symbols available for sidelink within a slot, as shown in Figure 5. In addition, in the frequency domain, the resource pool may be configured based on the number of consecutive subchannels, as shown in Figure 5. The sidelink resource pool configuration may be performed taking into account unlicensed band communication, as will be described later.

[0090] 6 is a diagram illustrating unlicensed bands by region for NR sidelink communication to which the present disclosure can be applied. In Table 8 above, the frequency range of R FR1 may be 450 MHz to 6 GHz, but the corresponding frequency range may be changed to 450 MHz to 7.125 GHz. The NR FR1 frequency range may be changed for the unlicensed band in the 6 GHz band, but is not limited to this.

[0091] By way of example, and without limitation, the unlicensed bands may be located below 1 GHz, 2.4 GHz, 5 GHz, 6 GHz, 37 GHz (US only), and 60 GHz. Referring to Figure 6, for example, the 5 GHz band in the system may be Band 46, defined as 5150-5925 MHz. Furthermore, by way of example, and without limitation, Band 49 (3550-3700 MHz) may be defined as a CBRS (citizens broadband radio service) band for LAA operations.

[0092] Figure 7 is a diagram illustrating the use of the 5 GHz unlicensed band to which the present disclosure can be applied. Referring to Figure 7, each band within the 5 GHz unlicensed band can be set, and the use of the unlicensed band can be set based on that band. For example, the bands can be divided into 20 MHz units for use, and each 20 MHz can be one channel.

[0093] In most areas, the low frequency band from 5150 to 5350 MHz is intended for indoor use and is regulated to have a maximum transmission power of 23 dBm. In the band above 5470 MHz, a transmission power of up to 30 dBm is permitted for outdoor use. In addition to the maximum transmission power limit, some areas may have additional requirements, such as the EIRP (effective isotropic radiated power) value shown in Table 9 below.

[0094] [Table 9]

[0095] Here, PSD (power spectral density) can mean that a device is limited to transmitting at full power within a reference bandwidth. As a specific example, European regulations may limit PSD to 10 dBm / MHz. Therefore, if the bandwidth is not 20 MHz, a device cannot transmit at a maximum transmission power of 23 dBm.

[0096] 8 is a diagram illustrating a method for increasing bandwidth in consideration of PSD limitations to which the present disclosure may be applied. As an example, consider the case of small data transmission, which requires only a small bandwidth, as shown in FIG. 8. In this case, if small data transmission is performed over a wide bandwidth, coverage can be expanded. Furthermore, transmission over a wide bandwidth can satisfy minimum bandwidth occupancy regulations. In consideration of the above, a method for transmitting small data over a wide bandwidth may be preferable.

[0097] For example, when a channel is occupied through a channel access procedure in an unlicensed band, the maximum channel occupancy time (COT), which corresponds to the maximum time that a channel can be occupied, can be set differently for each region. For example, Japan allows a maximum COT of 4 ms, while Europe allows a maximum COT of 8 ms or 10 ms. However, this is merely an example and is not limited to the above-described embodiment. For example, Europe can support Frame Based Equipment (FBE) and Load Based Equipment (LBE) rules. Here, FBE is set to High Performance Radio LAN (HiperLAN) / 2, and LBE can be adopted and applied in the Wi-Fi standard, and both can be supported in NR as a new communication system.

[0098] Further, as an example, the minimum occupied bandwidth may be a specification of a bandwidth that must be minimally occupied once a channel connection is successful. For example, the specification of the minimum occupied bandwidth may be set to occupy 80 to 90% or more of the nominal channel BW. As a specific example, when a terminal transmits a PUSCH to a base station in an unlicensed band, it may request that resources for the PUSCH be allocated to the entire band in an interlaced form with a specific bandwidth, but this may not be limited to this embodiment.

[0099] Furthermore, the dynamic frequency selection provision may be a provision to limit bandwidth usage in order to protect systems (e.g., radio) that have a high priority for using unlicensed bands. Furthermore, the transmit power control provision may be a provision to limit the use of transmit power lower than the maximum permitted transmit power value. Furthermore, the LBT (listen before talk) provision is a provision regarding procedures for channel access, and Europe can support FBE and LBE rules. At this time, FBE is Hiperlan / 2, and LBE can be adopted and applied in Wi-Fi standards, and both can be supported in NR.

[0100] For example, the 5 GHz unlicensed band can be used based on the above, but discussions regarding the use of the 6 GHz band are underway among various countries and organizations. Unlike the 5 GHz band, the 6 GHz band may be a band that has not yet been used by a mobile system. That is, unlike the 5 GHz band, which is shared by multiple mobile communication systems, the 6 GHz band can be used for a single, specific communication system. This reduces the problems and inefficiencies that arise from the coexistence of multiple different systems.

[0101] FIG. 9 is a diagram showing a method for setting a guard band in consideration of a shared band (e.g., an unlicensed band) within an intra-cell to which the present disclosure can be applied.

[0102] Referring to FIG. 9, to support wideband operation in shared spectrum access, the UE may receive an IntraCellGuardBandsPerSCS parameter for each of the uplink carrier (UL carrier) and the downlink carrier (DL carrier) from the base station based on the base station configuration. The UE may receive the IntraCellGuardBandsPerSCS parameter for each of the uplink carrier (UL carrier) and the downlink carrier (DL carrier) from the base station based on the base station configuration. 9, the UE may be provided with an intra-cell guard band of JPEG2025539703000016.jpg936. Referring to FIG. 9, the UE may be provided with higher layer signaling regarding the starting common resource block (CRB) for each guard band and the size of the number of CRBs. As an example, a CRB may be a resource block defined / set based on point A, which is the starting point of the transmission bandwidth on a carrier in the frequency domain. The UE may check information regarding point A through base station signaling and, based on the information, recognize the CRB position in the frequency domain. Here, each guard band is provided with a starting CRB. JPEG2025539703000017.jpg1326 is defined based on the parameters, and the size of the number of CRBs in each guard band is The UE may be provided with the above information through higher layer signaling based on the startCRB and nrofCRBs parameters, respectively. JPEG2025539703000019.jpg972, JPEG2025539703000020.jpg928 is the number of RB sets, and x may be set to DL or UL for downlink and uplink. The 928RB set may be configured as a resource block set (RBS) within one carrier through guard band configuration. For example, the guard band may be configured based on the IntraCellGuardBandsPerSCS parameter, thereby configuring an RBS within one carrier.

[0103] Here, each RBS frequency bandwidth may correspond to an LBT frequency bandwidth. That is, each RBS may be set to a bandwidth corresponding to an LBT procedure performed between a base station and a terminal. For example, in FIG. 9, RB set 1 (911) and RB set 2 (922) correspond to an LBT bandwidth, and if LBT is successful in that area, the band can be occupied to perform communication. That is, an RBS may correspond to an LBT bandwidth. For example, a transmitting node (e.g., a gNB or UE) can determine channel occupancy for an unlicensed band through an LBT channel access procedure performed on RBS resources corresponding to an LTE bandwidth. If the LBT procedure on one RBS is successful, the transmitting node can transmit on resources corresponding to that RBS.

[0104] Here, each RBS can be defined as a start CRB and an end CRB. The start CRB is JPEG2025539703000022.jpg1326 and the end CRB is JPEG2025539703000023.jpg1320. Here, the size of the guard band 913 may be nrofCRBs. As an example, the size of the guard band 913, nrofCRB, is determined by the subcarrier spacing μ and the carrier size It is not necessary to expect the size to be set to be smaller than the number of applicable intracell guard bands defined taking into consideration requirements regarding whether or not interference with wireless bandwidth is permitted by JPEG2025539703000024.jpg1322.

[0105] At this time, the start CRB and the end CRB for each RBS 911, 912 can be determined based on the RBS index s, and the RBS index s is JPEG2025539703000025.jpg971. That is, the RBS index s is JPEG2025539703000026.jpg may be a resource block having a size of 1323, JPEG2025539703000027.jpg1323 is the number of CRBs determined through the start CRB and end CRB based on the following Equation 3. Also, the start CRB and end CRB for each RBS may be as shown in Equation 4 and Equation 5.

[0106]

number

[0107]

number

[0108]

number

[0109] For example, if the UE is not provided with the IntraCellGuardBandsPerSCS parameter setting, the μ and carrier size of the carrier The CRB index for the nominal intra-cell guard band and RBS pattern based on JPEG2025539703000031.jpg1321 can be determined according to the requirements of the RF standard. Also, as an example, if the nominal intra-cell guard band and RBS pattern do not include the intra-cell guard band, the RBS of the corresponding carrier can be assumed to be 1.

[0110] For example, in FIG. 9, two LBT BWs (RBS0, RBS1) may be configured within one BWP 922 within one carrier bandwidth. In this case, one guard band 913 may be configured between the two RBSs 911, 913. The positions of the two RBSs 911, 913 may be determined as shown in FIG. 9 based on the above-mentioned higher layer parameters. Also, for example, when multiple BWPs 921, 923 are configured within one carrier bandwidth, the RBS associated with each BWP may be identified. Here, the RBSs corresponding to the first RBS (=s0, 912) and the last RBS (=s1, 911) of each BWP among the RBSs 911, 912 within the carrier may be indexed using the s0 and s1 indexes.

[0111] FIG. 10 illustrates an interlace-based RB resource allocation method applied to the present disclosure. PUCCH / PUSCH transmission can be performed using RB resources allocated on an interlace basis in an unlicensed band. Here, the reference point for the RB resources allocated on an interlace basis may be point A1010. The terminal may obtain information about point A1010 through base station signaling, as described above. Furthermore, CRBs may be resource blocks defined / configured with reference to point A1010, which is the starting point of the transmission bandwidth on a carrier. That is, when PUCCH / PUSCH transmission is performed on interlace-based RB resources, the interlaces can all be used on the carrier based on the same configuration with reference to reference point A1010 and CRBs. As an example, existing wireless communication systems (e.g., LTE LAA) and wireless communication systems (e.g., NR) can perform PUCCH / PUSCH transmission on interlace-based RB resources as described above, but are not limited thereto.

[0112] For example, in the case of a 15 kHz SCS, M=10 interlaces can be defined for all bandwidths. In the case of a 30 kHz SCS, M=5 interlaces can be defined for all bandwidths. Furthermore, X bits can be provided for interlace allocation in frequency resource allocation-related signaling. As a specific example, in the case of a 30 kHz SCS, if X is 5, the X bits can indicate all possible interlace combinations. As another example, in the case of a 15 kHz SCS, if X is 6, the X bits can indicate the starting interlace index and the number of consecutive interlaces. For example, 55 values ​​may be required based on the combination of the starting interlace index and the number of consecutive interlaces. Therefore, when indicated by 6 bits, there can be 9 remaining RIV values, and the 9 remaining RIV values ​​can indicate specific pre-defined interlace combinations.

[0113] Furthermore, Y bits can be provided for RB set allocation in frequency resource allocation-related signaling. The RB set allocation can be a start and end RB set based on the RIV format. Here, the RB sets can always be consecutive. Furthermore, as an example, when two adjacent RB sets are allocated, a guard band between the RB sets can be allocated and can be used as a frequency resource.

[0114] For example, in unlicensed bands, a method may be needed to allow various wireless access technologies / systems (e.g., Wi-Fi, LAA, NR-U, etc.) to use channels fairly and closely. For example, regulations (e.g., ETSI rules) for channel access may be provided, focusing on the above-mentioned 5 GHz and 6 GHz frequency bands, and items such as those shown in Table 10 below may be specified, but are not limited thereto.

[0115] [Table 10]

[0116] Here, the FBE (Frame Based Equipment) and LBE (Load Based Equipment) rules can be supported as channel access methods based on Table 10. As an example, the LBE channel access rule can take into account the factors in Table 11 below. Channel access can be performed by determining whether or not a channel is occupied based on CCA measurement. In addition, transmission based on an occupied channel can be performed after determining the transmission power based on the channel occupation.

[0117] [Table 11]

[0118] In addition, a channel access priority class (CANC) can be set for channel access, which may be similar to Table 12 below. Here, the priority class can define a priority based on a specific traffic type and quality of service (QoS) requirements. As an example, four priority classes can be defined in Table 12. Here, a different priority counter (p) value can be defined for each priority class. In this case, the higher the priority class, the lower the priority counter value.

[0119] Further, as an example, the channel occupancy time (CONT) may be a transmission burst interval. Here, the maximum COT limit may be determined differently for each priority class, and a higher priority class may have a shorter maximum COT interval. That is, the higher the priority class, the lower the priority counter value may be and the shorter the maximum COT interval may be.

[0120] Furthermore, as an example, the contention window (CW) may be a window used to select a counter value for performing a backoff procedure for channel access, where the contention window may be different for each priority class, which may be similar to Table 12 below.

[0121] [Table 12]

[0122] FIG. 11 is a diagram illustrating a method for performing a listen before talk (LBT) procedure in an unlicensed band to which the present disclosure can be applied. As an example, a Type 1 LBT procedure (LBT category 4) can be considered based on the LBE described above. The LBT procedure can be configured based on Category 1 to Category 4, which will be described later. Referring to FIG. 11, a transmitting node can wait for a defer period to determine whether a channel is available (S1110). Here, the defer period can be determined based on the priority class in Table 13 below. As an example, the defer period can measure whether a channel is available for at least 25 us. Here, it can be considered that feedback information regarding data transmission is transmitted within a maximum of 16 us. Taking the above into consideration, the defer period can measure whether a channel is available for at least 25 us.

[0123] Thereafter, if the node determines that the channel is available during the deferral period, it can perform a backoff procedure. At this time, the backoff counter N can be initialized to any value between 0 and the CW value (S1120). That is, any value between 0 and CW can be used as the backoff counter. Here, it is possible to count whether the channel is available based on 9us slots, and perform backoff by the backoff count value. Here, a larger average backoff value can be set based on a larger contention window, which can reduce the collision probability.

[0124] Thereafter, it is determined whether the backoff counter value is 0 (S1130). If the backoff counter value is 0, the node can perform transmission. The node can use the channel for transmission up to the maximum COT that can be occupied based on the priority class. On the other hand, if the backoff counter value is not 0, the backoff counter value can be decremented (S1140). Then, it is determined whether the next 9 us slot is idle (S1150). At this time, if the 9 us slot is idle, it checks again whether the backoff counter value is 0. If the backoff counter value is not 0, it repeats the operation of decrementing the backoff counter value. When the backoff counter value becomes 0, the above-mentioned transmission can be performed.

[0125] On the other hand, if the channel is not idle in the 9 us slot, the node waits again for the deferral interval and then checks whether the channel is available based on the backoff counter value (S1160). Based on the above, the node can occupy the unlicensed band and perform transmission. Furthermore, as an example, the deferral interval, possible contention window value, and maximum COT for the downlink / uplink based on the priority class may be the same as those in Table 13 below.

[0126] [Table 13]

[0127] Here, as an example, the size of the contention window may be adjusted based on HARQ feedback. Specifically, if the HARQ feedback received for the first transmission performed by the node within the COT is a NACK, the size of the contention window may be increased by up to twice to account for retransmission. On the other hand, if the HARQ feedback received for each transmission is an ACK, the size of the contention window may be reset to the CW min value. In this case, adjusting the size of the contention window for the first transmission within the COT may cause a collision in the first transmission after the node occupies the channel, and in such cases, it is necessary to update the size of the contention window. On the other hand, receiving a NACK for a transmission after the first transmission within the COT may be more likely to occur due to poor channel conditions or other reasons than a collision. Therefore, the size of the contention window may be adjusted based on the feedback of the first transmission within the COT, as described above.

[0128] As another example, the contention window adjustment for configured grant-based downlink / uplink (DL / UL) transmission may be performed based on feedback information on the downlink / uplink, respectively. Furthermore, as another example, when there is no downlink feedback transmission in uplink grant (UL grant-based uplink transmission), the contention window adjustment may be performed through a new data indicator (NDI), but is not limited to a specific embodiment.

[0129] Further, as an example, the energy detection (ED) threshold (TL) may be determined based on parameters, channel bandwidth, and other values. As another example, the ED threshold may be determined based on whether the carrier frequency is shared with other wireless access technologies (e.g., Wi-Fi) or whether the installation method ensures the use of only a specific wireless communication system (e.g., NR). As a specific example, the maximum threshold in the 5 GHz band coexisting with other systems may be set to −72 dBm for a 20 MHz carrier. Here, −72 dBm may be a value determined in comparison with other wireless communication systems (e.g., Wi-Fi systems), but is not limited to a specific embodiment. As another example, when the carrier frequency is used exclusively with a specific wireless communication system (e.g., NR), the maximum threshold may be −62 dBm for a 20 MHz carrier, and the threshold for uplink transmission may be set through RRC signaling based on regulations, but is not limited to a specific embodiment.

[0130] Next, FIG. 12 illustrates COT sharing and discovery burst transmissions applied to the present disclosure. Referring to FIG. 12, when a channel is occupied based on the aforementioned Type 1 LBT procedure, transmission can be performed within the COT. Here, Type 2 transmission can have three options based on the gap duration within the COT, as shown in Table 14 below. For example, Type 2A (LBT cat2) transmission sets the COT gap to 25 us or more and can be used for discovery burst transmission. For example, Type 2A can be considered for SSB transmission, but is not limited thereto. For another example, Type 2B transmission can apply a COT gap of 16 us. Furthermore, Type 2C transmission can apply a COT gap of 16 us or less. For example, if the next transmission is at most 16 us, idle sensing may not be required, and Type 2C can be applied.

[0131] [Table 14]

[0132] Here, due to the above-mentioned COT sharing, the gap may be smaller than the OFDM symbol duration. This is because the OFDM symbol-based resource allocation method may be insufficient, and a method of indicating CP extension can be applied taking the above-mentioned issue into consideration. That is, it is possible to indicate that the CP is extended earlier than the OFDM symbol boundary, and one of the following Table 15 can be indicated.

[0133] [Table 15]

[0134] As an example, Figure 13 is a diagram illustrating a method for applying a CP extension to an uplink when COT sharing is performed between a downlink and an uplink, which is applicable to the present disclosure. Figure 13 may illustrate, but is not limited to, a case in which a 16 us gap is present based on COT sharing and C2 is set to 1. Referring to Figure 13, a TA value can be considered to ensure a 16 us gap between the downlink and the uplink in a base station. As an example, the C value can be set through RRC signaling. Furthermore, a CP extension for uplink transmission can be indicated in an uplink grant.

[0135] As another example, a case where channel access is performed based on the FBE method can be considered. FBE may be a channel occupation method applicable to areas where the absence of other systems is guaranteed by regulation (e.g., a specific building or factory). Here, when channel access is performed based on the FBE method, transmission can start at a specific time. As a specific example, FIG. 14 illustrates a semi-static channel access procedure applicable to the present disclosure. Referring to FIG. 14, one COT can be started every Tx ms. At this time, the channel can be occupied if it is idle for at least 9 us before the COT. Here, Tx ms can be set to a value between 1 ms and 10 ms. Furthermore, the gap can be at least 5% of Tx. Here, COT sharing can be used similarly to LBE, and the gap can be at most 16 us.

[0136] As an example, Figure 15 illustrates a method for performing channel occupation applicable to the present disclosure. Referring to Figure 15, before performing transmission on an operating channel, a device may perform a CCA check based on energy detection with a CCA observation period of no less than 20 us. Furthermore, as an example, when transmitting a control frame (e.g., ACK, Block ACK) in consideration of multicast, the transmission may skip the CCA procedure and be performed immediately after packet reception. That is, the terminal may perform control frame transmission without a new CCA procedure, but may not exceed the maximum COT.

[0137] For example, if a device transmits an ACK / NACK signal after receiving data, the device can skip CCA, but this must be within the maximum COT. Also, for example, in short control signaling, a signal having a maximum duty cycle of 5% or less of 50 ms in the observation period can be transmitted without CCA, but this is not limited to a specific form.

[0138] Further, as an example, LBT categories can be considered, including category 1, which performs transmission immediately after a short switching gap, category 2, which performs LBT without random backoff, category 3, which performs a fixed-size contention window and random backoff, and category 4, which performs a variable-size contention window and random backoff.

[0139] Specifically, Category 1 may be a scheme in which transmission is performed immediately after a short switching gap. In this case, Category 1 can be used to perform transmission immediately after a switching gap within one COT. The switching gap from receive to transmit within one COT may include the transceiver switching time and may not be longer than 16 μs. Furthermore, as an example, Category 2 may be an operation in which LBT is performed without random backoff. For example, when performing LBT, initial CCA may be performed, and if the channel is idle, the channel is occupied and data is transmitted over an unlicensed channel. Here, random backoff counting may not be performed. On the other hand, Category 3 may be an LBT scheme in which a contention window of a fixed size is used and random backoff is performed. When LBT is performed based on Category 3, if initial CCA is performed and the channel is idle, random backoff may be performed within a fixed contention window (e.g., a fixed “q” value, where q is a value that determines the contention window size by selecting a random N counter between 0 and q). As an example, the random backoff operation may involve randomly selecting a counter value within the contention window, decrementing the count depending on whether the channel is idle for each ECCA slot, and occupying the channel when the value is 0.

[0140] As another example, Category 4 may be an LBT scheme with a variable-sized contention window and random backoff. Category 4 may differ from Category 3 in that it has a variable contention window. However, the operation of applying the N value based on the random backoff value to occupy a channel may be similar. That is, Category 4 may be the same as Category 3 except that the contention window size may vary based on time or events, and may be used in multiple wireless communication systems (e.g., LAA, NR-U, WiFi). This is not limited to a specific embodiment. Here, as an example, different channel access categories (e.g., LBT categories) may be defined and used for transmission of different channels / signals within one COT. Furthermore, as an example, in a new wireless communication system (e.g., NR-U), Category 4 LBT and Category 2 may be used within a COT, which may be similar to Table 16 below. Category 2 LBT may be used for discovery burst transmission when there is no unicast transmission and its transmission characteristics are constrained transmission, with a transmission time of 1 ms or less and a duty cycle of 5% or less, but is not limited to a specific form.

[0141] [Table 16]

[0142] The following describes a method for allocating frequency resources so that sidelink communication in a wireless communication system (e.g., NR) can operate on an unlicensed frequency band. For example, the size of an RB set included in 20 MHz in an unlicensed band (e.g., NR-U) of a current wireless communication system may vary depending on the SCS. For example, in the case of a 15 kHz SCS, the size of the RB set may be 100 to 110 PRBs. Furthermore, in the case of a 30 kHz SCS, the size of the RB set may be 50 to 55 PRBs. In this case, for example, when allocating RB resources based on interlaces, some interlaces may include 11 PRBs, while the remaining interlaces may include only 10 PRBs.

[0143] Here, as an example, a case where subchannel sizes are different to use the entire bandwidth in the sidelink may be considered. That is, a case where the number of PRBs included in each subchannel is set to be different may be considered. However, if different subchannel sizes are set, it may be difficult to ensure transmission when retransmissions are performed after the initial transmission of TBs having the same transport block size (TBS). In consideration of the above, the subchannel size (i.e., the number of PRBs) may be set to the same for each subchannel, but is not limited thereto. However, if the subchannel size is set to the same for each subchannel, some of the subchannels may not be used in one interlace based on interlace-based RB resource configuration.

[0144] 16 is a diagram illustrating a method for configuring RBSs in a BWP and a resource pool in a sidelink unlicensed band to which the present disclosure is applicable. The frequency domain resource structure of a sidelink unlicensed band wireless communication system (e.g., NR SL-U) may consider a BWP (bandwidth part), a RP (resource pool), interlaced RBs, and an RBS (RB set). For example, an RBS may also be considered in an unlicensed band wireless communication system (e.g., NR U), and is not limited to a specific embodiment.

[0145] Referring to Figure 16, one sidelink unlicensed band (SL-U) BWP 1610 may be configured in a sidelink terminal, one SL-U RP 1620 may be configured in the SL-UBWP 1610, and two RBSs 1631 and 1632 may be configured in the SL-U RP 1620. However, this is merely an example for convenience of explanation and is not limited to the above-mentioned embodiment. Here, as an example, an interlaced structure may be considered in an SL-U system to satisfy the OCB and PSD requirements required in the unlicensed band. That is, in an SL-U system, CRB indexing may be performed based on point A, which is a reference frequency point of one carrier, and a sidelink interlaced structure may be applied. In Figure 16, a frequency domain corresponding to CBR index 47 to CRB index 90 can be configured in the SL-U BWP 1610 based on the SL-U BWP 1610 configuration, and frequency resources including two RBSs 1631 and 1632 can be configured based on the SL-U RP 1620 configuration, but this is only an example and is not limited thereto. Hereinafter, a method for configuring frequency domain resources for an SL-U system as shown in Figure 16 and a method for allocating resources for actual SL-U data transmission based thereon will be described.

[0146] For example, the channel access procedure of a sidelink unlicensed band wireless communication system (e.g., NR SL-U) can apply the above-described Type 1 channel access procedure and Type 2 channel access procedure. Also, for example, UE-to-UE COT sharing can be applied between terminals operating in a sidelink unlicensed band. That is, a transmitting terminal can share a portion of unlicensed resources acquired through the LBT procedure with a receiving terminal or another terminal.

[0147] For example, in a sidelink unlicensed band wireless communication system (e.g., NR SL-U), frequency resources can be configured based on subchannels, as in an existing sidelink wireless communication system (NR SL). That is, the term "subchannel" can be used in NR SL-U as in NR SL. However, the names of subchannels can be configured differently in a sidelink unlicensed band wireless communication system (e.g., NR SL-U) and are not limited to a specific embodiment. For convenience of explanation, the following description will be based on subchannels.

[0148] As an example, an interlace-based RB structure for satisfying the requirements of the unlicensed spectrum described above may be defined with M RBs in the frequency domain. Here, the interlace-based RB structure may be defined as RBs spaced apart by a uniform number of RBs. As another example, the interlace-based RB structure may also be set to RBs spaced apart by a non-uniform number of RBs, and is not limited to a specific embodiment.

[0149] Here, the interlace-based RB structure may be pre-configured commonly for NR SL UEs, cell-specific or carrier-specific, based on bandwidth / pneumatics. As another example, the interlace-based RB structure may be configured specific to a physical link between UEs through higher layer configuration, and is not limited to a specific embodiment. In this case, the interlace-based RB structure may be applied to all interlaces regardless of carrier bandwidth. Therefore, the interlace-based RB structure may be configured by a CRB defined based on point A, a specific reference point in the frequency domain. Here, one sub-channel may be pre-defined to have k interlaces. As another example, one sub-channel may be configured with k interlaces through higher layer signaling. k may be the number of interlaces per sub-channel. The number of interlaces per sub-channel may have a fractional (or decimal) or integer value, as will be described later. Furthermore, as an example, when multiple RBSs are configured in one SL BWP, the frequency resource allocation instruction may include RBS allocation information and sub-channel or interlace-based RB frequency resource allocation information.

[0150] As another example, in a sidelink unlicensed spectrum system (e.g., NR SL-U), resource allocation can be performed based on interlace-based RB units rather than "subchannel" units. In this case, the frequency resource allocation unit can be an interlace-based RB unit rather than the existing subchannel, but this is merely an example and is not limited to a specific embodiment.

[0151] Hereinafter, both subchannel units and interlace-based RB units can be considered as resource allocation units in the frequency domain. Herein, a subchannel can be configured with k interlaces or a number of consecutive RBs. However, for convenience of explanation, a "subchannel unit" based on an interlace structure will be described as a unit of frequency resource allocation. However, frequency resource allocation can also be configured in interlace-based RB units rather than in subchannel units by applying the proposed method, and is not limited to a specific form.

[0152] Here, as an example, FIG. 17 illustrates a method for configuring a sidelink unlicensed band resource pool based on contiguous frequency resources to which the present disclosure is applied. Referring to FIG. 17, the sidelink unlicensed band resource pool 1710 may also be configured based on contiguous frequency resources. In this case, the sidelink unlicensed band resource pool 1710 may be indicated only by an RBS index. More specifically, referring to FIG. 17, a case may be considered in which only one RBS 1720 is configured in the sidelink unlicensed band resource pool 1710 in consideration of the LBT procedure for the unlicensed band. Here, the sidelink unlicensed band resource pool configuration may be instructed to the UE based on contiguous frequency resources from a frequency domain perspective (hereinafter, referred to as Case 1). As an example, to satisfy the above-mentioned requirements such as OCB and PSD on the unlicensed band, most frequency resources (e.g., >80%) in at least one LBT BW (RBS 1720) may be configured in one resource pool. Considering the above-mentioned provisions, there may be a limit to configuring more than one resource pool for one RBS in one SL BWP. That is, since only one resource pool exists in one RBS, it can be configured to include most of the frequency resources, thereby satisfying the above-mentioned regulations. In this case, for example, sidelink transmission can be performed by selecting resources to be used for actual transmission through interlace-based frequency resource allocation in a resource pool configured on a contiguous frequency resource basis.

[0153] On the other hand, Figure 18 illustrates frequency resource-based sidelink unlicensed band resource pool configuration using interlace allocation to which the present disclosure is applied. Referring to Figure 18, in order to satisfy the regulations on frequency utilization in the unlicensed band, a resource pool can be configured using new interlace RBs or interlace RB-based subchannels from the initial resource pool configuration step. That is, interlace RBs or interlace RB-based subchannels can be used from the resource pool configuration. As an example, referring to Figure 18, when configuring a frequency resource-based sidelink unlicensed band resource pool using interlace allocation, frequency resources for the resource pool configuration can be indicated based on a combination of RBSs and interlace / subchannel indexes (hereinafter referred to as Case 2).

[0154] That is, in Figure 18, resource pools 1821 and 1822 can be configured using interlaced RBs or interlaced RB-based subchannels from the initial resource pool configuration step to satisfy requirements such as OCB and PSD. Therefore, the sidelink unlicensed band resource pools 1821 and 1822 do not need to have contiguous subchannels or PRB structures. That is, the sidelink unlicensed band resource pools 1821 and 1822 can be configured with non-contiguous PRBs based on interlaced allocation, thereby satisfying requirements such as OCB and PSD. Furthermore, unlike Case 1 (Figure 17), multiple sidelink unlicensed band resource pools can be configured within one RBS, thereby providing flexibility in resource configuration.

[0155] Here, the resource pool configuration methods corresponding to the above-mentioned Case 1 and Case 2 can both consider an interlace-based frequency resource allocation method. However, there may be a difference in whether the frequency resources are configured as contiguous frequency resources similar to the existing NR SL in the step of configuring one resource pool (Case 1), or whether a discontinuous resource pool is configured taking into account the interlace structure from the resource pool configuration step (Case 2). Based on the above, an RBS-based sidelink unlicensed band resource pool configuration method will be described below.

[0156] FIG. 19 illustrates a sidelink unlicensed band resource pool configuration method applicable to the present disclosure.

[0157] The sidelink unlicensed band resource pool can be configured based on the RBS. For example, the sidelink resource pool can be configured based on consecutive subchannels through the resource pool start point and the number of subchannels in the resource pool. For example, as described above, the sidelink unlicensed band pool can also be configured as a resource pool corresponding to an LBT BW through the resource pool start point and the number of subchannels in the resource pool based on consecutive subchannels. However, to efficiently configure the sidelink unlicensed band resource pool, the RBS setting and index can be taken into consideration. That is, the sidelink unlicensed band resource pool can be configured as one resource pool by indicating the RBS setting / index in resource pool configuration signaling.

[0158] As a specific example, a resource pool can be configured with one or more RBSs. Therefore, a specific resource pool can be configured with consecutive RBS indexes associated with the resource pool, allowing for frequency configuration for the resource pool. Here, when the frequency configuration of a resource pool is performed based on consecutive RBS indexes, the resource pool can utilize gap band resources between RBSs, thereby maximizing frequency resource efficiency. Consider the case where four RBSs are configured within one sidelink BWP. Here, a gap band can be configured between each RBS, allowing for three gap band configurations to be configured. In this case, the resource pool of the sidelink unlicensed band can be configured with consecutive RBS indexes based on the LBT BW. Specifically, frequency domain resource configuration for one resource pool configuration can be provided through RBS index information. For example, frequency domain resource configuration for one resource pool configuration can be provided through a starting RBS index and consecutive RBS number information.

[0159] Referring to FIG. 19, configuration 0 (1910) can set a resource pool to four consecutive RBSs, from RBS#0 to RBS#3. Here, configuration 0 (1910) can specify a resource pool configuration by specifying a starting RBS index, RBS#0, and the number of consecutive RBSs, four. As another example, configuration 1 (1920) can specify two consecutive RBSs, with RBS#0 and RBS#1 set to sidelink resource pool#0 and RBS#2 and RBS#3 set to sidelink resource pool#1. Here, configuration 1 can specify a resource pool configuration by specifying a starting RBS index, RBS#0 and RBS#2, and the number of consecutive RBSs, two, for each resource pool. As another example, configuration 2 (1930) can set sidelink resource pool #0 for RBS #0, sidelink resource pool #1 for RBS #1, sidelink resource pool #2 for RBS #2, and sidelink resource pool #3 for RBS #3. In this case, since each resource pool corresponds to a respective RBS, the corresponding RBS index and RBS number 1 can be indicated. As another example, configuration 3 (1940) can set sidelink resource pool #0 for RBS #0, sidelink resource pool #1 for RBS #1 and RBS #2, and sidelink resource pool #2 for RBS #3. Here, the starting RBS index and RBS number corresponding to each sidelink resource pool can be indicated, thereby indicating the configuration for each resource pool. As another example, in configuration 4 (1950), sidelink resource pool #0 can be configured for RBS #0, RBS #1, and RBS #2, and sidelink resource pool #1 can be configured for RBS #3. Here, the starting RBS index and the number of RBSs corresponding to each sidelink resource pool can be specified, thereby specifying the configuration for each resource pool.However, the resource pool configuration in FIG. 19 is merely an example and is not limited to the above-described embodiment.

[0160] In this case, as an example, if multiple RBSs are configured in the SL BWP, frequency resource information for configuring a resource pool of the sidelink unlicensed band can be indicated to the terminal through at least one of interlace / subchannel-based configuration information and RBS configuration information.

[0161] Here, when both interlace / subchannel-based configuration information and RBS configuration information are provided, frequency resource configuration information for one resource pool can be provided to a UE through intersecting frequency resource information. Also, when an intra-cell guard band (GB) existing between consecutive RBSs is configured in one resource pool, the frequency resource corresponding to the GB can also be used for sidelink unlicensed band communication as part of the resource pool.

[0162] Based on the above, a method for allocating frequency resources for sidelink unlicensed band data transmission / reception in the frequency domain will be described below. The following description is applicable to the methods for configuring a resource pool for at least one of the interlace / subchannel-based configuration information and the RBS configuration information, and is not limited to a specific embodiment.

[0163] Also, as an example, the following matters can be applied to both the case where consecutive frequency resources are configured in one resource pool (Case 1) and the case where a resource pool is configured based on discontinuous frequency resources (Case 2) in the above description. However, for convenience of explanation, the following will be described based on the case where one resource pool is configured based on consecutive frequency resources (Case 1), but the following matters can also be applied interchangeably to the case where a resource pool is configured on discontinuous frequency resources (Case 2), and are not limited to a specific form.

[0164] For example, the frequency resource configuration of the sidelink unlicensed band may be configured based on consecutive frequency resources according to starting subchannel information and the number of consecutive subchannels. Also, the time resource configuration of the sidelink unlicensed band may be configured by excluding SSB transmission slots, reserved slots, and / or TDD UL-DL configuration, and then applying a bitmap to the remaining slots to configure a resource pool, and the present invention is not limited to a specific embodiment.

[0165] However, the following description will focus on frequency resource configuration for the sidelink unlicensed band. For example, the instruction for the sidelink resource set (SL RBS) index (i.e., bit size) may be configured taking into account the total number of SL RBSs included in one SL BWP. In this case, the instruction for the SL RBS index may indicate one or more SL RBS indexes. For example, the SL RBSs may be configured contiguously in the frequency domain, but this is not a limitation. However, for convenience of explanation, the following description will be based on SL RBSs configured contiguously in the frequency domain.

[0166] Further, as an example, frequency resource reservation may be indicated via a physical sidelink control channel (PSCCH). In this case, the frequency resource reservation indication may be performed in the second slot or the second / third slot based on the PSCCH received in the lowest interlace index among the interlace indexes defined within one carrier bandwidth. The interlace structure may be set to 10 interlaces (i.e., M=10) for 15 kHz SCS and 5 interlaces (i.e., M=5) for 30 kHz SCS based on the LBT BW considered in the unlicensed band, as described above. Specifically, the interlace structure may be set as described above, taking into account that the number of RBs for constituting one RBS is 100 to 110 RBs for 15 kHz SCS and 50 to 55 RBs for 30 kHz SCS based on the LBT BW.

[0167] That is, in the case of a 15 kHz SCS, a partial resource (i.e., RB) of the same interlace may exist for every 10 RBs. However, the interlace value may be configured as another value based on at least one of another RBS size (LBT BW), SCS, and the number of RBs constituting one interlace, and is not limited to a specific embodiment.

[0168] For example, the sidelink unlicensed (SL-U) band of a current wireless communication system (e.g., NR) differs from existing wireless communication systems in that it must be configured taking into account various regulations required on unlicensed channels and the unlicensed band channel environment. The SL-U may consider various slot structures (e.g., slot, non-slot) for efficient operation in the unlicensed band. As another example, the SL-U may apply an interlaced-RB-based transmission as a channel transmission method. As another example, the SL-U may apply a new resource allocation method, a channel access procedure considering LBT, a dynamic PSFCH resource structure, and other physical channel structures, and is not limited to a specific form.

[0169] Here, there is a need to perform a HARQ procedure that takes into account additional slot structures, new channel access procedures, and additional transmission methods and resource allocation methods to meet other unlicensed band regulations. As a specific example, a transmitting terminal may receive SL HARQ-ACK information from a receiving terminal via a PSFCH and then report it to a base station (gNB) via an uplink channel (Uu link, PUCCH or PUSCH). A method for this will be described below.

[0170] A transmitting terminal performing sidelink communication may receive sidelink HARQ (SL HARQ) feedback information (ACK or NACK) corresponding to PSSCH / PSCCH transmission from a receiving terminal via a PSFCH channel. As another example, the transmitting terminal may determine SL HARQ feedback information based on whether or not the PSFCH is received within a PSFCH occasion as a PSFCH reception slot. As a specific example, the transmitting terminal may transmit PSCCH / PSSCH to multiple receiving terminals via sidelink communication based on a groupcast type. Here, the receiving terminal may transmit only a NACK based on groupcast option 1. As an example, groupcast option 1 may optionally operate to feed back a negative acknowledgement only when the receiving terminal fails to decode the PSSCH. That is, if the receiving terminal successfully decodes the PSSCH, the receiving terminal does not need to transmit a separate feedback response to the transmitting terminal, and the transmitting terminal may recognize that the receiving terminal has received the PSSCH if it does not receive a separate feedback response from the receiving terminal. Conversely, when the transmitting terminal receives a feedback response from the receiving terminal, it can recognize that the receiving terminal has failed to decode the PSSCH. That is, the transmitting terminal can recognize a NACK based on whether or not it has received the PSFCH.

[0171] The transmitting terminal may obtain SL feedback information from the receiving terminal in different manners depending on the SL HARQ feedback transmission method and the cast type of sidelink communication. The transmitting terminal may report the SL HARQ feedback information received from the receiving terminal to the base station. As an example, but not limited to, the transmitting terminal may operate based on sidelink resource allocation mode 1 in which sidelink communication resources are allocated from the base station. The transmitting terminal may monitor physical downlink control information (PDCCH) scrambled with a sidelink radio network temporary identifier (SL-RNTI) or SL configured scheduling (CS)-RNTI to detect downlink control information (DCI) format 3_0. Here, DCI format 3_0 may be a DCI format that carries grant information related to sidelink communication. As an example, the terminal can report SL HARQ feedback information to the base station via a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) on a primary cell (PCell) or a UL PCell in a PUCCH group including a cell to which the PDCCH is transmitted.

[0172] The transmitting terminal may report SL HARQ feedback information associated with SL configured grant Type 1 or Type 2 PSSCH transmissions within one time period determined based on the Sl-PeriodCG parameter to the base station. Specifically, the transmitting terminal may transmit SL HARQ feedback information related to PSSCH transmissions on PUCCH occasions that exist after the last time resource in the set of time resources within one time period based on the Sl-PeriodCG parameter to the base station.

[0173] At this time, for example, when a transmitting terminal performs SL HARQ reporting to a base station, the transmitting terminal may report ACK or NACK to the base station as SL HARQ feedback information. Here, a method for determining SL HARQ-ACK information may be required, and a method for doing so will be described below.

[0174] When a receiving terminal transmits a PSFCH to a transmitting terminal, the transmitting terminal may not be able to obtain SL HARQ feedback information due to an LBT failure in the SL-U unlicensed band. In consideration of the above, the SL-U may be configured to have one or more PSFCH reception occasions (hereinafter referred to as ROCs) corresponding to one PSSCH transmission, taking into account LBT failure. When the transmitting terminal reports SL HARQ feedback to the base station, the SL HARQ feedback reporting method may be performed in different ways depending on the scheduling transmission method for sidelink transmission (e.g., dynamic grant, configured grant type 1 or type 2), cast type, HARQ-ACK feedback option (e.g., unicast, groupcast option 1 and option 2), uplink PUCCH resource configuration, and other configurations. As an example, the following description will be given based on a case where multiple PSFCH ROCs corresponding to one PSSCH are configured in the SL-U, taking into account LBT (listen-and-before-talk, channel access procedure) failure. However, the present invention is not limited to this.

[0175] When multiple PSFCH ROCs corresponding to one PSSCH are configured, the transmitting terminal may generate HARQ-ACK information to report SL HARQ feedback information. The transmitting terminal may transmit the generated HARQ-ACK information to the base station via an uplink channel. As an example, one PSFCH ROC associated with one PSSCH transmission in an existing SL system may be implicitly determined. However, the following description will be given based on a case where multiple PSFCH ROCs associated with one PSSCH transmission are provided in consideration of the LBT characteristics of the SL-U system. The multiple PSFCH ROCs corresponding to one PSSCH transmission may configure resources based on at least one of the time, frequency, space, and code domains. The terminal may be configured or instructed of the configured resource information in advance based on higher layer signaling.

[0176] As an example, a value indicating the minimum time gap between the PSSCH and the PSFCH (PSSCH-to-PSFCH minimum time gap) may be set by a higher layer parameter. The value of the minimum time gap between the PSSCH and the PSFCH (PSSCH-to-PSFCH minimum time gap) is the minimum time required for a receiving terminal to perform PSFCH transmission after receiving the PSSCH, and may be determined in slot units. As a specific example, if the value of the minimum time gap between the PSSCH and the PSFCH (PSSCH-to-PSFCH minimum time gap) is set to one slot, the receiving terminal may perform PSFCH transmission in the earliest PSFCH slot that exists one slot or later after receiving the PSSCH. Here, the value of the minimum time gap between the PSSCH and the PSFCH (PSSCH-to-PSFCH minimum time gap) may be set to multiple values ​​based on higher layer signaling. When multiple minimum time gap values ​​between PSSCH and PSFCH (PSSCH-to-PSFCH minimum time gap) are configured, the receiving terminal can perform SL HARQ feedback transmission based on multiple PSFCH ROCs associated with SL HARQ feedback for one PSSCH reception. Specifically, after receiving the PSSCH, when the minimum time gap value between PSSCH and PSFCH (PSSCH-to-PSFCH minimum time gap) is reached, the receiving terminal can perform SL HARQ feedback transmission on the earliest PSFCH. The receiving terminal can perform SL HARQ feedback transmission on each PSFCH corresponding to each minimum time gap value between PSFCHs (PSSCH-to-PSFCH minimum time gap).

[0177] FIG. 20 is a diagram illustrating the relationship between the PSSCH and PSFCH ROC sets applied to the present disclosure.

[0178] Referring to FIG. 20, there may be PSFCH ROCs 2020 and 2030 associated with the reception of one PSSCH 2010. When a receiving terminal receives a PSSCH from a transmitting terminal in SL-U, the receiving terminal performs LBT to occupy the channel and then transmits SL HARQ feedback information over the PSFCH. As an example, in FIG. 20, the two PSFCH ROCs 2020 and 2030 may be set to multiple values ​​in consideration of a case where the channel cannot be occupied when the above-described channel access procedure (e.g., channel access procedure type 1 or type 2) is performed. That is, the terminal may be provided with multiple minimum time gap setting information based on one PSSCH transmission time point and may be provided with multiple PSFCH ROCs in the time domain based on this information. Hereinafter, for convenience of explanation, a set of PSFCH ROCs associated with one PSSCH reception will be referred to as a PSFCH ROC set. However, this is merely an example for convenience of explanation, and other names may be used and are not limited to a specific form.

[0179] Furthermore, as an example, one or more PSFCH ROCs associated with one PSSCH HARQ feedback can be configured from the frequency perspective, and multiple PSFCH ROC resources in the frequency domain may be configured within one RB set (RBS) or across multiple RBSs, and are not limited to a specific form.

[0180] As another example, from the viewpoint of coding, one or more PSFCH ROCs associated with one PSSCH may be provided using multiple ID values ​​or other indicator information for one PSSCH, i.e., one or more PSFCH ROCs associated with one PSSCH may be provided using not only frequency domain resources but also code domain resources.

[0181] As another example, a new PSFCH format based on DMRS (Demodulation Reference Signal) can be considered, where one or more PSFCH antenna ports for one PSFCH can provide multiple PSFCH ROCs, i.e., multiple PSFCH ROCs can be provided from a spatial perspective.

[0182] As an example, the UE may generate SL HARQ feedback information to report to a base station (e.g., a gNB) through PUCCH or PUSCH transmission based on multiple PSFCH ROCs, as will be described below.

[0183] The terminal may receive an indication of one of the SL HARQ feedback modes based on one sidelink control information (SCI) format. For example, the terminal may generate one SL HARQ-ACK codeword containing HARQ-ACK information. Furthermore, the terminal may prep Based on the value, the base station can expect to receive PUCCH resources or PUSCH resources. prep The value may refer to a time value at which the UE considers that a PUCCH resource or a PUSCH resource is not provided after the end of the last OFDM symbol of the last PSFCH ROC associated for generating HARQ-ACK information reported through the PUCCH or PUSCH. That is, the UE considers that a PUCCH resource or a PUSCH resource is not provided after the end of the last OFDM symbol of the last PSFCH ROC associated for generating HARQ-ACK information reported through the PUCCH or PUSCH. prep Only the PSFCH ROC before the value can be considered, and the PUCCH resource or PUSCH resource starting symbol from T prep The PSFCH ROC in the value does not need to be considered.

[0184] As a specific example, SL HARQ-ACK feedback information for unicast may be considered. The unicast type may be a unicast type indicated by one SCI format. Here, one or more PSFCH ROC sets associated with the indication may be configured. The transmitting terminal may generate HARQ-ACK information as a value such as HARQ-ACK information determined from the last PSFCH ROC set in the time domain, and the HARQ-ACK information may be SL HARQ feedback information reported by the transmitting terminal to the base station. More specifically, if the transmitting terminal has received a PSFCH at least once in the last PSFCH ROC set, the transmitting terminal may generate HARQ-ACK information associated with the PSFCH ROC set based on the last received PSFCH among the received PSFCHs. On the other hand, if the transmitting terminal has not received a PSFCH in the last PSFCH ROC set and has not received an ACK in the previous PSFCH ROC set, the transmitting terminal may generate a NACK.

[0185] As another example, if the transmitting terminal does not receive a PSFCH in the last PSFCH ROC set but receives a PSFCH at least once in the previous PSFCH ROC set, the transmitting terminal may generate HARQ-ACK information associated with the PSFCH ROC set based on the last received PSFCH in the PSFCH ROC set. Here, all PSFCH ROC sets are generated based on the PUCCH occasion. prep As an example, a particular PSFCH ROC may exist before time T prep If the PSFCH ROC is located at a later time, the PSFCH ROC may not be considered in the PUCCH occasion. prep may determine the last PSFCH ROC considered in a PUCCH occasion.

[0186] FIG. 21 illustrates a method for generating SL HARQ-ACK information using a PSFCH ROC set in a single RBS-based unicast transmission according to the present disclosure. Referring to FIG. 21, unicast PSSCH transmission may be indicated by one SCI. When unicast PSSCH transmission is indicated by one SCI, the transmitting terminal may generate SL HARQ feedback information based on multiple PSFCH ROCs 2130, 2140 in the PSFCH ROC set associated with the PSSCH. As an example, the terminal may receive one sidelink grant information configuration from the base station via a PDCCH (e.g., DCI format 3_0 or DCI format 3_1). In FIG. 21, the terminal may be assigned two PSSCH transmission slots 2110, 2120 from the base station, but this is not intended to be limiting. As another example, the terminal may be provided with two PSSCH slot resources within one configured grant (CG) transmission period based on a configured grant (CG) configuration, but this is not intended to be limiting.

[0187] Referring to FIG. 21 , multiple PSFCH ROCs 2130, 2140 corresponding to each PSSCH transmission slot 2110, 2120 may be set at different times. However, this is merely an example for convenience of explanation and is not limiting. In FIG. 21 , two PSFCH ROCs may be associated with each PSSCH 2110, 2120 in consideration of LBT failure. The UE may transmit SL HARQ feedback information to the base station over an uplink channel on the earliest PUCCH transmission occasion after a processing delay time between the PSFCH and the PUCCH. As an example, the SL HARQ feedback information that the UE must report to the base station over an uplink channel may be generated for the SL HARQ report based on whether the PSFCH is received in the last PSFCH ROC 2140 of the two PSFCH ROCs 2130, 2140.

[0188] As another example, the HARQ-ACK information may be generated by considering at least one of the frequency domain, the code domain, and the spatial domain in addition to the time domain. For example, a terminal may be configured with one or more RB sets in a resource pool, and the associated PSFCH ROCs may be located in different RBSs. In the above case, there may be one or more last PSFCH ROCs. Here, if the terminal has received a PSFCH at least once in the last PSFCH ROC set, the terminal may determine the HARQ-ACK information from the last received PSFCH corresponding to at least one of the lowest RBS index, interlace index, RB index, subchannel index, and PSFCH resource index of the last received PSFCH. On the other hand, if the terminal is unable to receive a PSFCH in the last PSFCH ROC set and has not received any ACK in the previous PSFCH ROC set, the terminal may generate a NACK and report it to the base station.

[0189] 22 is a diagram illustrating a method for generating SL HARQ-ACK information using a PSFCH ROC set in multi-RBS-based unicast according to the present disclosure. Referring to FIG. 22, multiple PSFCH ROCs 2230, 2240, 2250, and 2260 associated with PSSCHs 2210 and 2220 transmitted over multiple RBSs can be considered. Here, the multiple PSFCH ROCs 2230, 2240, 2250, and 2260 may exist over multiple RBSs. Referring to FIG. 22, if a terminal performs the last PSFCH reception over two RBSs, the terminal needs to determine HARQ-ACK information for SL HARQ reporting.

[0190] For example, in FIG. 22, the HARQ-ACK information may be determined based on the lowest RBS index, but is not limited thereto. A UE can receive data on PSSCH 2210, 2220 resources on two RBSs provided by one sidelink grant. Referring to FIG. 22, the UE may generate SL HARQ feedback information by considering the last received PSFCH 2240, 2260 among multiple PSFCH ROCs 2230, 2240, 2250, 2260 associated with the PSSCH 2210, 2220 on the two RBSs, respectively. For example, in FIG. 22, the UE may generate HARQ-ACK information corresponding to the PSFCH 2260 of RBS #0, which has the lowest RBS index among the last received PSFCHs 2240, 2260, as SL HARQ feedback information to be reported to the base station. For example, in FIG. 22, T prep can determine the last PSFCH ROC considered in a PUCCH occasion, as described above.

[0191] As another example, HARQ-ACK feedback for groupcast option 2 may be considered. For example, the terminal may consider HARQ-ACK feedback for groupcast option 2 based on SCI format 2-A in which the cast type indication field value is '01'. For example, when HARQ feedback is performed based on groupcast, all receiving terminals may operate to feed back a positive acknowledgment or a negative acknowledgment based on whether PSSCH decoding is successful, which may be an Option 2 operation. Here, a terminal operating in SL-U may receive ACK, which is HARQ feedback information for the corresponding groupcast PSSCH transmission, in at least one PSFCH ROC among a plurality of PSFCH ROCs. If the terminal receives ACK for the corresponding groupcast PSSCH transmission in at least one PSFCH ROC among a plurality of PSFCH ROCs, the terminal may determine that the SL HARQ feedback information to report to the base station is an ACK. Otherwise, the terminal may determine that the SL HARQ feedback information to report to the base station is a NACK.

[0192] As another example, HARQ-ACK feedback for groupcast option 1 may be considered. For example, a terminal may consider HARQ-ACK feedback for groupcast option 1 based on SCI format 2-A in which the cast type indication field value is '11'. For example, when HARQ feedback is performed based on groupcast, a receiving terminal may operate to feed back a negative acknowledgement only when PSSCH decoding fails, which may be an option 1 operation. For example, in the existing groupcast option 1, if a terminal in a group receives a PSSCH transmission and determines it to be an ACK, it does not perform PSFCH transmission in the associated PSFCH ROC, but performs PSFCH transmission only if it determines it to be a NACK. On the other hand, in SL-U, channel occupancy may fail due to an LBT failure. The transmitting terminal may be unable to determine whether a terminal in the group has determined it to be an ACK and has not performed PSFCH transmission, or whether it has failed to transmit a NACK due to an LBT failure, and may need to perform an operation to do so.

[0193] As a specific example, HARQ-ACK feedback can be performed in the same manner as in Groupcast Option 2. That is, even when Groupcast Option 1 is indicated by the SCI, all receiving terminals can operate to feed back a positive or negative acknowledgement based on whether PSSCH decoding is successful. When a terminal operating in an unlicensed band receives an ACK, which is HARQ feedback information for the corresponding groupcast PSSCH transmission, in at least one PSFCH ROC among multiple PSFCH ROCs, the terminal can determine and generate SL HARQ feedback information for the corresponding PSSCH (groupcast) as an ACK. Otherwise, it generates a NACK. Here, as an example, when Groupcast Option 1 considers ACK / NACK transmission and reception to adjust the contention window size (CWS), it can determine HARQ-ACK information taking CWS adjustment into account.

[0194] As another example, when groupcast option 1 is indicated by the SCI, a terminal operating in an unlicensed band may determine and generate SL HARQ feedback information as an ACK if there is no PSFCH reception on a PSFCH ROC in all of a plurality of PSFCH ROC sets. That is, a terminal operating in an unlicensed band may determine that PSSCH reception has been performed only if there is no PSFCH reception, and may otherwise generate a NACK.

[0195] As another example, when Groupcast Option 1 is indicated by the SCI, a terminal operating in an unlicensed band may determine and generate SL HARQ feedback information as an ACK if the number of times PSFCH reception on a PSFCH ROC in a plurality of PSFCH ROC sets is absent is greater than a specific threshold.A terminal operating in an unlicensed band may determine and generate NACK if the number of times PSFCH reception on a PSFCH ROC in a plurality of PSFCH ROC sets is absent is less than a specific threshold.

[0196] As another example, when Groupcast Option 1 is indicated by the SCI, a terminal operating in an unlicensed band may determine and generate HARQ-ACK information as an ACK if there is no PSFCH reception on the last PSFCH ROC in all PSFCH ROC sets corresponding to PSSCH transmission. A terminal operating in an unlicensed band may generate a NACK in any other case.

[0197] As another example, new sidelink status information indicating an LBT failure (e.g., an LBT failure indicator) may be configured in addition to the HARQ-ACK information. For example, if the UE receives additional LBT failure indicator information through at least one PSFCH ROC, the UE may determine and generate the HARQ-ACK information as a NACK. A UE operating in an unlicensed band may generate an ACK in any other case.

[0198] Furthermore, the above-described matters may be applied under specific conditions. As a specific example, the above-described matters may be applied based on at least one of Table 17 below. That is, the above-described matters may be applied when COT sharing is indicated by a PSSCH transmitting terminal or when the information is shared. As another example, the above-described matters may be applied when only Type 2 channel access is applied to all of multiple PSFCH ROCs associated with PSSCH transmission. As another example, the above-described matters may be applied when there is no channel access procedure based on a short control signal provision or when PSFCH transmission is performed by applying a Type 2-A channel access procedure, but are not limited thereto.

[0199] [Table 17]

[0200] As another example, the UE may perform LBT in SL-U, and if the LBT is successful and the channel is occupied, the UE may perform PSCCH / PSSCH transmission. Here, if the UE fails the LBT, the PSCCH / PSSCH may not be transmitted on the provided resources. The UE receives a PDCCH (DCI format 3_0 or DCI format 3_1) from the base station and is allocated resources for sidelink communication through a dynamic grant or a configured grant. Here, the UE may perform a procedure of reporting SL HARQ feedback information to the base station in consideration of a case where the UE does not receive the PSCCH / PSSCH due to an LBT failure.

[0201] As a specific example, if the transmitting terminal does not perform PSSCH transmission in any of the resources provided by DCI format 3_0 due to an LBT failure, the terminal may generate an ACK for the PSSCH. Here, the priority value of the ACK may be the same as the priority value of the PSSCH that could not be transmitted due to an LBT failure. As another example, if the transmitting terminal does not perform PSSCH transmission in any of the periodic resources for one CG due to an LBT failure, the terminal may generate an ACK for the PSSCH. Here, the priority value of the ACK may be the same as the priority value of the PSSCH that could not be transmitted due to an LBT failure. Although the transmitting terminal was unable to transmit the PSCCH / PSSCH in the provided resources due to an LBT failure, the transmitting terminal may perform the procedure for determining SL HARQ feedback information as described above in order to report SL HARQ feedback information to the base station.

[0202] Furthermore, if the transmitting terminal does not perform PSSCH transmission in any of the resources provided by DCI format 3_0 due to an LBT failure, the terminal may generate a NACK for the PSSCH. Here, the priority value of the NACK may be the same as the priority value of the PSSCH that could not be transmitted due to an LBT failure. As another example, if the transmitting terminal does not perform PSSCH transmission in any of the periodic resources for one CG due to an LBT failure, the terminal may generate a NACK for the PSSCH. Here, the priority value of the NACK may be the same as the priority value of the PSSCH that could not be transmitted due to an LBT failure. Although the transmitting terminal was unable to transmit the PSCCH / PSSCH in the provided resources due to an LBT failure, the transmitting terminal may perform the procedure for determining SL HARQ feedback information as described above in order to report SL HARQ feedback information to the base station.

[0203] Here, as an example, if the transmitting terminal does not perform PSSCH transmission in any of the resources provided by DCI format 3_0 due to an LBT failure, the terminal may report LBT failure indicator information to the base station through an uplink channel. As an example, the terminal may transmit the LBT failure indicator information to the base station together with SL HARQ feedback information including an ACK or SL HARQ feedback information including a NACK, and this is not limited to a specific embodiment.

[0204] FIG. 23 illustrates a method for generating and reporting SL HARQ feedback information to a base station to which the present disclosure may be applied. Referring to FIG. 23, a first wireless user equipment may transmit a PSSCH to a second wireless user equipment (S2310). Here, the first wireless user equipment may be a transmitting terminal, and the second wireless user equipment may be a receiving terminal, but is not limited thereto. The first wireless user equipment may then receive SL HARQ-ACK information for the PSSCH based on a PSFCH ROC associated with the PSSCH (S2320). The first wireless user equipment may generate SL HARQ feedback information based on the SL HARQ-ACK information (S2330) and report the generated SL HARQ feedback information to the base station (S2340). Here, the PSSCH may be associated with a PSFCH ROC set including multiple PSFCH ROCs based on an unlicensed band.

[0205] Also, as an example, consider a case where a first radio user equipment performs SL communication with a second radio user equipment based on SL unicast. As an example, the SL HARQ-ACK information may be determined based on the last PSFCH ROC set in the time domain among at least one PSFCH ROC set associated with the PSSCH. Specifically, the SL HARQ-ACK information may be generated based on the last received PSFCH among at least one PSFCH received in the last PSFCH ROC set in the time domain, as described above. On the other hand, if a PSFCH cannot be received in the last PSFCH ROC set in the time domain among at least one PSFCH ROC set associated with the PSSCH and a PSFCH is not received in a PSFCH ROC set before the last PSFCH ROC set, the SL HARQ-ACK information may be generated as a NACK. As another example, when at least one PSFCH ROC set associated with a PSSCH is located in different RBSs and there are multiple last PSFCH ROC sets, if multiple PSFCHs are received within the multiple last PSFCH ROC sets, the SL HARQ feedback information may be generated based on the PSFCH with the lowest RBS index among the multiple received PSFCHs.

[0206] As another example, a case may be considered in which a first wireless user equipment performs SL communication in which the first wireless user equipment receives SL HARQ ACK information from all second wireless user equipments in a group using the SL groupcast scheme, and if the first wireless user equipment receives SL HARQ-ACK information related to the SL groupcast PSSCH transmission in at least one PSFCH ROC among a plurality of PSFCH ROCs in the PSFCH ROC set, the SL HARQ feedback information may be determined as an ACK.

[0207] As another example, a case may be considered in which a first wireless user equipment performs SL communication by receiving SL HARQ ACK information from a second wireless user equipment that transmits a NACK within a group using the SL groupcast method, in which the first wireless user equipment may determine the SL HARQ feedback information as an ACK based on whether or not a PSFCH has been received on a PSFCH ROC within all PSFCH ROC sets corresponding to the PSSCH transmission.

[0208] FIG. 24 is a diagram showing an apparatus configuration to which the present disclosure can be applied.

[0209] 24, a first device 2400 and a second device 2450 may communicate with each other. In this case, as an example, the first device 2400 may be a base station device, and the second device 2450 may be a terminal device. As another example, both the first device 2400 and the second device 2450 may be terminal devices. That is, the first device 2400 and the second device 2450 may be devices that communicate with each other based on NR-based communication.

[0210] As an example, consider a case where the first device 2400 is a base station device and the second device 2450 is a terminal device. In this case, the base station device 2400 may include a processor 2420, an antenna unit 2412, a transceiver 2414, and a memory 2416. The processor 2420 performs baseband-related signal processing and may include an upper layer processing unit 2430 and a physical layer processing unit 2440. The upper layer processing unit 2430 may process operations of a Medium Access Control (MAC) layer, a Radio Resource Control (RRC) layer, or higher layers. The physical layer processing unit 2440 may process operations of a physical (PHY) layer (e.g., uplink receive signal processing, downlink transmit signal processing). In addition to performing baseband-related signal processing, the processor 2420 may control the overall operation of the base station device 2400. The antenna unit 2412 may include one or more physical antennas. When multiple antennas are included, MIMO (Multiple Input Multiple Output) transmission and reception may be supported. The base station device 2400 may also support beamforming. The memory 2416 may store information processed by the processor 2420, software associated with the operation of the base station device 2400, an operating system, applications, etc., and may include components such as buffers. The processor 2420 of the base station device 2400 may be configured to implement the operation of a base station in the embodiments described herein.

[0211] The terminal device 2450 may include a processor 2470, an antenna unit 2462, a transceiver 2464, and a memory 2466. As an example, in the present invention, the terminal device 2450 may communicate with the base station device 2400. As another example, in the present invention, the terminal device 2450 may perform sidelink communication with another terminal device. That is, the terminal device 2450 of the present invention refers to a device capable of communicating with at least one of the base station device 2400 and another terminal device, and is not limited to communication with a specific device. The processor 2470 performs baseband-related signal processing and may include an upper layer processing unit 2480 and a physical layer processing unit 2490. The upper layer processing unit 2480 may process operations of the MAC layer, the RRC layer, or higher layers. The physical layer processing unit 2490 may process operations of the PHY layer (e.g., downlink receive signal processing, uplink transmit signal processing, sidelink signal processing). In addition to performing baseband-related signal processing, the processor 2470 may control the overall operation of the terminal device 2450. The antenna unit 2462 may include one or more physical antennas, and when multiple antennas are included, MIMO transmission and reception may be supported. Beamforming may also be supported. The memory 2466 may store information processed by the processor 2470, software associated with the operation of the terminal device 2450, an operating system, applications, etc., and may include components such as a buffer. The terminal device 2450 according to an example of the present invention may be associated with a vehicle. For example, the terminal device 2450 may be incorporated into, located in, or located on the vehicle. The terminal device 2450 according to the present invention may also be the vehicle itself. The terminal device 2450 according to the present invention may be at least one of a wearable terminal, an AV / VR terminal, an IoT terminal, a robot terminal, and a public safety terminal.The terminal device 2450 to which the present invention can be applied may include any of various types of communication devices that support interactive services using a sidelink for services such as Internet connection, service execution, navigation, real-time information, autonomous driving, safety, and risk diagnosis, etc. It may also include any type of communication device that can perform a sidelink operation, such as an AR / VR device, or a sensor that performs a relay operation.

[0212] Here, vehicles / terminals to which the present invention is applied may include autonomous vehicles / terminals, semi-autonomous vehicles / terminals, non-autonomous vehicles / terminals, etc. Meanwhile, although the terminal device 2450 according to an example of the present invention is described as being associated with a vehicle, one or more of the UEs may not be associated with a vehicle. This is merely an example, and the application of the present invention should not be interpreted as being limited by the described example. Furthermore, the terminal device 2450 according to an example of the present invention may transmit a PSSCH to another terminal device. Here, the terminal device 2450 may be a transmitting terminal, and the other terminal device may be a receiving terminal, but is not limited thereto. Thereafter, the terminal device 2450 may receive SL HARQ-ACK information for the PSSCH based on the PSFCH ROC associated with the PSSCH. The terminal device 2450 may generate SL HARQ feedback information based on the SL HARQ-ACK information and report the generated SL HARQ feedback information to the base station device 2400. Here, the PSSCH may be associated with a PSFCH ROC set including multiple PSFCH ROCs based on the unlicensed band.

[0213] Also, as an example, a case may be considered in which the terminal device 2450 performs SL communication with another terminal device based on SL unicast. As an example, the SL HARQ-ACK information may be determined based on the last PSFCH ROC set in the time domain among at least one PSFCH ROC set associated with the PSSCH. Specifically, the SL HARQ-ACK information may be generated based on the last received PSFCH among at least one PSFCH received in the last PSFCH ROC set in the time domain, as described above. On the other hand, if a PSFCH cannot be received in the last PSFCH ROC set in the time domain among at least one PSFCH ROC set associated with the PSSCH and a PSFCH is not received in a PSFCH ROC set before the last PSFCH ROC set, the SL HARQ-ACK information may be generated as a NACK. As another example, when at least one PSFCH ROC set associated with a PSSCH is located in different RBSs and there are multiple last PSFCH ROC sets, if multiple PSFCHs are received within the multiple last PSFCH ROC sets, the SL HARQ feedback information may be generated based on the PSFCH with the lowest RBS index among the multiple received PSFCHs.

[0214] As another example, consider a case where the terminal device 2450 performs SL communication in which the terminal device 2450 receives SL HARQ ACK information from all other terminal devices in a group through an SL groupcast scheme. Here, if the terminal device 2450 receives SL HARQ-ACK information related to the SL groupcast PSSCH transmission in at least one PSFCH ROC among a plurality of PSFCH ROCs in a PSFCH ROC set, the SL HARQ feedback information may be determined as an ACK.

[0215] As another example, a case can be considered in which the terminal device 2450 performs SL communication by receiving SL HARQ-ACK information from other terminal devices that transmit NACKs within a group using the SL groupcast method. Here, the SL HARQ feedback information may be determined as an ACK based on whether or not a PSFCH is received on a PSFCH ROC within all PSFCH ROC sets corresponding to PSSCH transmission.

[0216] Furthermore, various embodiments of the present disclosure may be implemented using hardware, firmware, software, or a combination thereof, etc. In the case of a hardware implementation, the implementation may be using one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), general processors, controllers, microcontrollers, microprocessors, etc.

[0217] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause the operations of the methods of the various embodiments to be performed on a device or computer, as well as non-transitory computer-readable media on which such software or instructions are stored and which can be executed on a device or computer.

[0218] The various embodiments of the present disclosure do not enumerate all possible combinations, but are intended to describe representative aspects of the present disclosure, and the matters described in the various embodiments may be applied independently or in combination of two or more. [Industrial Applicability]

[0219] The above may also be applied to other systems.

Claims

1. 1. A first wireless user equipment (UE) operating in a sidelink unlicensed spectrum in a wireless communication system, comprising: at least one antenna for transmitting and receiving one or more radio signals; at least one processor; and a memory that stores instructions for the wireless user device when executed by the at least one processor; The operation of the wireless user equipment is to: Transmitting sidelink (SL) data to a second wireless user equipment via a physical sidelink shared channel (PSSCH); receiving SL hybrid automatic repeat request (HARQ)-ACK information for the PSSCH based on a physical sidelink feedback channel (PSFCH) reception occasion (ROC) associated with the PSSCH; generating SL HARQ feedback information based on the SL HARQ-ACK information and reporting the SL HARQ feedback information to the base station; The first wireless user equipment, wherein the PSFCH is associated with a PSFCH ROC set including a plurality of the PSFCH ROCs based on the unlicensed band.

2. The first wireless user equipment (10) of claim 1, wherein the first wireless user equipment (10) performs SL communication with the second wireless user equipment (10) based on SL unicast.

3. The SL HARQ-ACK information is determined based on a last PSFCH ROC set in a time domain among the at least one PSFCH ROC set associated with the PSSCH; 3. The first wireless user equipment of claim 2, wherein the SL HARQ-ACK information is generated based on a last received PSFCH among at least one PSFCH received in a last PSFCH ROC set on the time domain.

4. 4. The first wireless user equipment according to claim 3, wherein, when a PSFCH cannot be received in a last PSFCH ROC set on the time domain among the at least one PSFCH ROC set associated with the PSSCH and a PSFCH has not been received in a PSFCH ROC set prior to the last PSFCH ROC set, the first wireless user equipment generates the SL HARQ-ACK information as a NACK.

5. 3. The first wireless user equipment according to claim 2, wherein, when at least one PSFCH ROC set associated with the PSSCH is located in a different resource block set (RBS) and there are a plurality of last PSFCH ROC sets, if a plurality of PSFCHs are received within the plurality of last PSFCH ROC sets, the first wireless user equipment generates the SL HARQ feedback information based on a PSFCH having a lowest RBS index among the plurality of received PSFCHs.

6. 2. The first wireless user equipment according to claim 1, wherein, when the first wireless user equipment performs SL communication in which SL HARQ-ACK information is received from all of the second wireless user equipments in a group via an SL groupcast method, the SL HARQ feedback information is determined as ACK if the first wireless user equipment receives the SL HARQ-ACK information for SL groupcast PSSCH transmission in at least one PSFCH ROC among a plurality of PSFCH ROCs in a PSFCH ROC set.

7. 2. The first wireless user equipment according to claim 1, wherein, when the first wireless user equipment performs SL communication in a manner of receiving SL HARQ-ACK information from the second wireless user equipment that transmits a NACK within a group in a SL groupcast manner, the SL HARQ feedback information is determined as an ACK based on whether or not a PSFCH on a PSFCH ROC is received in all PSFCH ROC sets corresponding to a PSSCH transmission.

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