Method and apparatus for performing sidelink communications over unlicensed spectrum

Abstract

A method for a terminal to perform sidelink communication based on an unlicensed band in a wireless communication system includes the steps of: receiving sidelink resource pool configuration information from a base station based on higher layer signaling; generating an SL grant when data is generated on an LCH based on the sidelink resource pool configuration information; selecting a sidelink resource pool depending on whether HARQ feedback is set for the data generated on the LCH based on the sidelink resource pool configuration information; and selecting sidelink transmission resources from the selected sidelink resource pool to perform sidelink transmission.

Description

[Technical Field]

[0001] The present disclosure relates to a method and apparatus for performing sidelink communications over unlicensed spectrum in a wireless communication system. [Background technology]

[0002] The International Telecommunication Union (ITU) is developing the International Mobile Telecommunication (IMT) framework and standards, and has recently been discussing fifth-generation (5G) communications 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, 5G communication can support the transmission of physical signals or physical channels through multiple beams to overcome poor channel conditions such as high path loss, phase noise, and frequency offset that occur at high carrier frequencies. This enables 5G communication to support applications such as enhanced Mobile Broadband (eMBB), massive Machine Type Communications (mMTC), and Ultra Reliable and Low Latency Communication (URLLC).

[0005] V2X communication, a communication method for exchanging or sharing information such as traffic conditions while communicating with road infrastructure and other vehicles while driving, can also be considered. V2X can include vehicle-to-vehicle (V2V), which refers to Long Term Evolution (LTE) / New Radio (NR)-based communication between vehicles, vehicle-to-pedestrian (V2P), which refers to LTE / NR-based communication between vehicles and personally carried devices, and vehicle-to-infrastructure / network (V2I / N), which refers to LTE / NR-based communication between vehicles and roadside units / networks. Here, roadside units (RSUs) can be transportation infrastructure entities implemented by base stations or fixed devices. For example, they can be entities that transmit speed notifications to vehicles. Summary of the Invention [Problem to be solved by the invention]

[0006] The technical problem of the present disclosure relates to a method and apparatus for performing sidelink (SL) communication in a wireless communication system.

[0007] The technical problem of the present disclosure relates to a method and apparatus for configuring an SL resource pool on an unlicensed band.

[0008] The technical problem of the present disclosure relates to a method and apparatus for selecting an SL resource pool configured on an unlicensed band based on an LBT (listen before talk) result.

[0009] The technical problem of the present disclosure relates to a method and apparatus for selecting an SL resource pool configured on an unlicensed band based on an LBT counter.

[0010] The technical problem of the present disclosure relates to a method and apparatus for selecting an SL resource pool configured on an unlicensed band based on a CBR (channel busy ratio).

[0011] The technical problem of the present disclosure relates to a method and apparatus for selecting a specific transmission opportunity based on candidate transmission opportunities in a resource pool that includes multiple LBT bandwidths.

[0012] The technical problem of the present disclosure relates to a method and apparatus for controlling the minimum time gap between transmission opportunities taking into account the maximum channel occupation time (MCOT) of an unlicensed band.

[0013] The technical problems to be solved by the present disclosure are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Means for solving the problem]

[0014] According to one aspect of the present disclosure, a method for a terminal performing sidelink communication based on an unlicensed band in a wireless communication system includes the steps of: receiving sidelink resource pool configuration information from a base station based on higher layer signaling; generating a sidelink grant (SL grant) when data is generated on a logical channel (LCH) based on the sidelink resource pool configuration information; selecting a sidelink resource pool depending on whether hybrid automatic repeat and request (HARQ) feedback is configured for the data generated on the LCH based on the sidelink resource pool configuration information; and selecting sidelink transmission resources from the selected sidelink resource pool to perform sidelink transmission, wherein the terminal performs a listen before talk (LBT) operation on the unlicensed band during the process of selecting the sidelink resource pool, and can select the sidelink resource pool based on at least one of an LBT result, an LBT failure counter, and a CBR.

[0015] Furthermore, according to one aspect of the present disclosure, when HARQ feedback is configured in the terminal, the terminal selects a sidelink resource pool from at least one or more sidelink resource pools configured with a PSCCH (physical sidelink feedback channel), and when HARQ feedback is not configured in the terminal, the terminal can select a resource pool from at least one or more sidelink resource pools regardless of whether a PSFCH is configured.

[0016] Furthermore, according to one aspect of the present disclosure, the terminal can select a resource pool from at least one or more sidelink resource pools included in the LBT bandwidth that successfully occupies the channel based on the LBT result.

[0017] Furthermore, according to one aspect of the present disclosure, the terminal may select a sidelink resource pool from among at least one sidelink resource pool included in an LBT bandwidth whose LBT counter is smaller than a preset value based on the LBT counter.

[0018] Furthermore, according to one aspect of the present disclosure, when a first sidelink resource pool including a plurality of LBT bandwidths is configured in a terminal, at least one candidate transmission opportunity is configured in the first sidelink resource pool including the plurality of LBT bandwidths based on each LBT bandwidth, and when the first sidelink resource pool is selected based on at least one of the LBT result, the LBT failure counter, and the CBR, the terminal can select a first transmission opportunity from at least one candidate transmission opportunity in the first sidelink resource pool based on at least one of the LBT result, the LBT failure counter, and the CBR. [Effects of the Invention]

[0019] According to the present disclosure, sidelink (SL) communication can be performed in a wireless communication system.

[0020] According to the present disclosure, a method for configuring an SL resource pool on an unlicensed band can be provided.

[0021] According to the present disclosure, a method can be provided for selecting an SL resource pool configured on an unlicensed band based on an LBT result.

[0022] According to the present disclosure, a method can be provided for selecting an SL resource pool configured on an unlicensed band based on an LBT counter.

[0023] According to the present disclosure, a method for selecting an SL resource pool configured on an unlicensed band based on CBR can be provided.

[0024] According to the present disclosure, a method for selecting a particular transmission opportunity based on candidate transmission opportunities in a resource pool that includes multiple LBT bandwidths can be provided.

[0025] According to the present disclosure, a method for controlling the minimum time gap between transmission opportunities can be provided that takes into account the MCOT of the unlicensed spectrum.

[0026] The effects obtained by the present disclosure are not limited to the effects described above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief explanation of the drawings]

[0027] [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 unlicensed spectrum applicable to the present disclosure. [Figure 11]FIG. 11 is a diagram illustrating a sidelink resource pool to which the present disclosure can be applied. [Figure 12] FIG. 12 illustrates a method in which a terminal applicable to the present disclosure operates based on sidelink resource allocation mode 2. [Figure 13] FIG. 13 illustrates a sidelink HARQ entity operation method applicable to the present disclosure. [Figure 14] FIG. 1 illustrates a sidelink process applicable to the present disclosure. [Figure 15] FIG. 15 is a diagram illustrating a sidelink resource pool configured with an unlicensed single band that is applicable to the present disclosure. [Figure 16] FIG. 16 shows a SL BWP configuration that operates in a wide band. [Figure 17] FIG. 17 is a diagram illustrating a resource pool selection procedure applicable to the present disclosure. [Figure 18] FIG. 18 is a diagram illustrating a method in which a terminal applicable to the present disclosure performs resource selection taking into account the LBT result. [Figure 19] FIG. 19 illustrates a method for selecting a resource pool based on an LBT failure counter applicable to the present disclosure. [Figure 20] FIG. 20 is a diagram illustrating a method in which a terminal applicable to the present disclosure performs resource selection taking into account an LBT counter. [Figure 21] FIG. 21 illustrates a method for generating sidelink grants and selecting resources based on CBR to which the present disclosure is applicable. [Figure 22] FIG. 22 illustrates a CBR window in a sidelink unlicensed band applicable to the present disclosure. [Figure 23] FIG. 23 is a diagram illustrating a resource pool configuration in an SL BWP applicable to the present disclosure. [Figure 24] FIG. 24 is a diagram illustrating a method in which a terminal applicable to the present disclosure performs resource selection taking into account an LBT counter. [Figure 25] FIG. 25 is a diagram illustrating sidelink operation to which the present disclosure is applicable. [Figure 26] FIG. 26 is a diagram showing an SL BWP including multiple RB sets. [Figure 27] FIG. 27 illustrates a method for selecting a transmission opportunity based on candidate transmission opportunities applicable to the present disclosure. [Figure 28] FIG. 28 illustrates a method for determining transmission opportunities based on LBT operations applicable to the present disclosure. [Figure 29] FIG. 29 may be a diagram illustrating a case where a minimum time gap is guaranteed in a transmission opportunity applicable to the present disclosure. [Figure 30] FIG. 30 illustrates a method for determining transmission opportunities in consecutive slots in an unlicensed spectrum applicable to the present disclosure. [Figure 31] FIG. 31 is a flowchart illustrating a method in which a terminal to which the present disclosure may be applied performs sidelink communication. [Figure 32] FIG. 32 is a flowchart illustrating a method by which a terminal to which the present disclosure can be applied performs sidelink communication. [Figure 33] FIG. 33 is a diagram showing a base station apparatus and a terminal apparatus to which the present disclosure can be applied. BEST MODE FOR CARRYING OUT THE INVENTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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).

[0039] 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.

[0040] First, a brief description will be given of the physical resource structure of the NR system to which the present invention is applied.

[0041] FIG. 1 is a diagram for explaining an NR frame structure to which the present disclosure can be applied.

[0042] 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.

[0043] 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.

[0044] 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:

[0045]

number

[0046] 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 is 39936T c or 25600T c It can be. 39936T c is 20.327μs, and 25600T c is 13.030μs. Also, at the millimeter wave (mmWave) frequency FR2 (Frequency Range 2), N TA,offset is 13792T c At this time, 39936T c is 7.020μs.

[0047] FIG. 2 is a diagram illustrating an NR resource structure to which the present disclosure may be applied.

[0048] 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.

[0049] In the frequency domain, one resource block (RB) consists of 12 REs, and an index (n PRB ) 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.

[0050]

number

[0051] 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.

[0052] 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.

[0053] Table 1 below shows examples of pneumoradio supported by the NR system.

[0054] [Table 1]

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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).

[0059] 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.

[0060] 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).

[0061] [Table 2]

[0062] 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.

[0063] [Table 3]

[0064] 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.

[0065] 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.

[0066] [Table 4]

[0067] 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.

[0068] 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. This allows new features to 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.

[0069] 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.

[0070] [Table 5]

[0071] 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.

[0072] 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.

[0073] Here, NR V2X capability is not necessarily limited to supporting only V2X services, and may optionally support the use of a certain V2X RAT.

[0074] 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).

[0075] 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.

[0076] 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.

[0077] FIG. 3 is a diagram illustrating an NR sidelink slot structure to which the present disclosure can be applied.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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.

[0083] 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.

[0084] [Table 6]

[0085] [Table 7-1] [Table 7-2] [Table 7-3]

[0086] NOTE 1: For the standardized PQI to QoS characteristic mapping, the table will be extended or updated to support service requirements for other specific V2X services. (NOTE 1: For Standardized PQI to QoS characteristics mapping, the table will be extended / updated to support service requirements for other identified V2X services.)

[0087] Note 2: PQI can also be used for services other than V2X. (NOTE 2: The PQIs may be used for other services than V2X.)

[0088] Next, the sidelink HARQ procedure will be described. Whether a V2X terminal reports HARQ feedback is indicated by higher layer (e.g., RRC) configuration and SCI signaling (e.g., 2nd SCI). For example, when a V2X terminal performs communication based on groupcast, it can determine whether to report HARQ feedback based on the distance between the transmitting terminal and the receiving terminal.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] [Table 8]

[0096] 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.

[0097] More specifically, the time resource for resource pool configuration provided in the NR sidelink is the time period of the resource pool, the set of sidelink slots within one resource pool application period (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) may refer to the remaining slots in a situation where a multiple of the length of the bitmap on the time resource (e.g., sl-TimeResource) is not established, and may not be used as an NR sidelink resource.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] [Table 9]

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] Referring to FIG. 9, to support wideband operation in shared spectrum access, the UE may receive an IntraCellGuardBandsPerSCS parameter for each uplink carrier (UL carrier) and downlink carrier (DL carrier) from the base station based on the base station configuration. The UE may receive N subcarrier spacing indexes (μ) on one carrier. RB-set,x A terminal may be provided with an intra-cell guard band of -1. Referring to FIG. 9, the terminal 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. For 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 terminal may check information regarding point A through base station signaling and, based on the information, may recognize the CRB position in the frequency domain. Here, each guard band is provided with a starting CRB. JPEG2025532838000015.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. JPEG2025532838000017.jpg972, JPEG2025532838000018.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.

[0113] 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.

[0114] Here, each RBS can be defined as a start CRB and an end CRB. The start CRB is JPEG2025532838000020.jpg1326 and the end CRB is JPEG2025532838000021.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 JPEG2025532838000022.jpg1322 will interfere with the wireless bandwidth.

[0115] 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 JPEG2025532838000023.jpg970. That is, the RBS index s is JPEG2025532838000024.jpg may be a resource block having a size of 1323, JPEG2025532838000025.jpg1323 is the number of CRBs determined through the start CRB and end CRB based on Equation 3. Also, the start CRB and end CRB for each RBS may be as shown in Equation 4 and Equation 5.

[0116]

number

[0117]

number

[0118]

number

[0119] 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 JPEG2025532838000029.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 carrier can be assumed to be 1.

[0120] 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.

[0121] FIG. 10 is a diagram illustrating unlicensed bands applicable to the present disclosure. Referring to FIG. 10, the NR-U band, an unlicensed band for a wireless communication system (e.g., NR), may include two frequency ranges consisting of a low-frequency band below 7 GHz and a high-frequency band of 60 GHz. However, these bands are merely examples and are not limited thereto. As an example, in FIG. 10, the 2.4 GHz band is used for industrial scientific medical (ISM), the 3.5 GHz band is used for citizens broadband radio services (CBRS), and the 5 GHz to 6 GHz band is used for unlicensed national information infrastructure (UNII). The UNII (5.925 GHz to 7.125 GHz) band may include multiple bands (UNII-1, UNII-2, ..., UNII-8). The multiple bands within UNII (UNII-1, UNII-2, ..., UNII-8) may have different transmit power, indoor / outdoor operation, maximum effective isotropic radiated power (EIRP), and dynamic frequency selection (DFS) requirements for each band, but are not limited to any particular form.

[0122] The 5 GHz to 6 GHz band can be divided into non-overlapping 20 MHz channel bandwidths. Here, channels with wider bandwidths, such as 40 MHz, 80 MHz, and 160 MHz, can be configured based on the boundaries. For example, a portion of the 6 GHz band can coexist with systems using backhaul communications (UNII-5, UNII-7), satellites (UNII-5), broadcasting (UNII-6, UNII-8), and ultra-wideband (UWB) systems (UNII-6). The number of channels in the UNII-5 band (5.925 to 6.425 GHz) can be 24, 12, 6, and 4 at 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively. Furthermore, the UNII-5 band (5.925 to 6.425 GHz) can be used indoors and outside protected areas. Here, the indoor EIRP may be determined as 30 dBm (AP) and 24 dBM (UE), and the outdoor EIRP may be determined as 36 dBm (AP) and 30 dBM (UE), but this is not limited to a specific form.

[0123] The channel described below may be part of one carrier or multiple consecutive resource blocks (RBs) within a carrier. As an example, a channel access procedure may be a procedure for checking a channel based on sensing to perform transmission. When performing the channel access procedure, a base station or a terminal performs energy detection on a slot-by-slot basis, and if the energy is below a preset threshold, the base station or a terminal may determine that the channel is idle. A method for operating in an unlicensed band based on the above-mentioned operation will be described below.

[0124] FIG. 11 is a diagram illustrating a sidelink resource pool to which the present disclosure can be applied. Referring to FIG. 11, a terminal may be configured with multiple transmit (Tx) resource pools (RPs) and receive (Rx) RPs. Resource pools may be differentiated by an identification (ID) and added or removed from the terminal. Furthermore, as an example, each resource pool configuration may be different. Specifically, the PSCCH, PSSCH, and PSFCH configurations of a resource pool may be different for each resource pool. Furthermore, a resource pool may be configured with a starting position of a subchannel indicating the location of resources in the frequency aspect within a SL BWP, the number of RBs, and a subchannel size. Furthermore, a resource pool may be configured with the location of time resources in the time aspect in a bitmap format. Here, time resources are mapped excluding slots used for SSB and uplink (UL), and may be repeatedly applied for each bit configured within a system frame number (SFN).

[0125] As a specific example, referring to FIG. 11, the UE may determine resource locations in a specific resource pool within the SL BWP. The subchannel size may refer to a physical resource block (PRB), which is the smallest unit for selecting resources. Also, 'sl-StartRBsubchannel' may indicate the start RB of a subchannel within the SL BWP, 'sl-RB-Number' may indicate the number of RBs available within the SL BWP, and 'sl-SubchannelSize' may indicate the size of one subchannel. The UE may determine how many subchannels to use within the SL BWP based on the above parameters. Furthermore, as an example, time resources may be indicated in slot units via 'sl-TimeResource'. As a specific example, if the UE receives '0011111100' as a 10-bit indicator, the UE may use resources in slots indicated by 1, excluding slots including reserved slot SSBs. Furthermore, the UE may not use slots that are not included in the above-mentioned subchannel RBs within the SL BWP or that are indicated by 0 in 'sl-TimeResource'. Furthermore, as an example, up to four SL BWPs may be configured, and one of the configured BWPs may be activated and used. Also, up to eight Tx resource pools and up to 16 Rx resource pools may be configured within the SL BWP, and are not limited to a specific embodiment.

[0126] Based on the above, sidelink communication can be performed in an unlicensed band, and based on this, a listen before talk (LBT) operation can be performed. That is, before transmitting a signal in an unlicensed band, the terminal checks whether the channel is in use, and can transmit the signal if it confirms that the channel is idle. As an example, a method for the terminal to select a transmission (or retransmission) resource from a resource pool based on the above operation will be described below.

[0127] For example, the UE may perform transmission over a sidelink shared channel (SL-SCH). Specifically, the UE may receive a sidelink grant via at least one of physical downlink control channel (PDCCH) reception and radio resource control (RRC). When the UE receives a PDCCH scrambled with a sidelink configured scheduling-radio network temporary identifier (SLCS-RNTI) and with a new data indicator (NDI) indicating 1, the UE may determine that it has received a dynamic sidelink grant and perform an operation based thereon. For example, the SLCS-RNTI may be an identifier indicating configured scheduling for sidelink communication. When the UE receives DCI scrambled with the SLCS-RNTI, the UE may perform sidelink communication based on the preconfigured scheduling. As another example, the UE may automatically generate a sidelink grant in its MAC layer. That is, the UE's MAC layer may have a sidelink grant for determining PSCCH and PSSCH durations in an activated SL BWP.

[0128] As a specific example, if sidelink resource allocation mode 1 is configured in the UE, the UE may perform an operation based on a grant received in a PDCCH occasion. For example, sidelink resource allocation mode 1 may be a mode in which sidelink resources are scheduled by a base station. The base station may schedule sidelink resources to the UE through DCI of the PDCCH, and the UE may perform sidelink communication with other UEs through resources designated by the base station. For example, the UE may receive DCI scrambled with SL-RNTI (sidelink-RNTI). Here, the NDI included in the DCI may not be toggled, and not toggling the NDI may indicate a retransmission. If the NDI included in the DCI is not toggled, the UE may determine PSCCH and PSSCH durations for performing one or more retransmissions associated with a single MAC protocol data unit (PDU) through the received sidelink grant.

[0129] On the other hand, when the NDI included in the DCI is toggled (i.e., when a new transmission is performed), the UE can determine the PSCCH and PSSCH duration for performing a single MAC PDU-related transmission through the received sidelink grant. In addition, if a retransmission resource is configured, the UE can also determine a resource for performing a single MAC PDU retransmission. For example, when the UE receives a retransmission sidelink grant for a MAC PDU for which ACK has been received, the UE can remove the PSCCH and PSSCH duration configured for performing the MAC PDU retransmission.

[0130] As another example, the UE may receive DCI scrambled with the SLCS-RNTI. Here, if the DCI is activated and indicates retransmission for a specific HARQ process ID in the configured sidelink grant (CG), the UE may determine the PSCCH and PSSCH durations for single MAC PDU transmission. As another example, if the DCI indicates deactivation of type 2 CG, the UE may generate a sidelink grant confirmation for the configured sidelink grant. Specifically, the UE may generate a sidelink grant confirmation MAC CE. On the other hand, if the DCI indicates activation of type 2 CG, the UE may generate a sidelink grant confirmation for the configured sidelink grant and determine the PSCCH and PSSCH durations for multiple MAC PDU transmissions. For example, type 1 CG may be a CG type in which the UE receives a grant via RRC and performs transmission over scheduled resources without a DCI or other trigger. On the other hand, Type 2 CG may be a CG type in which, after the UE receives a grant through RRC, it activates the CG and performs transmission when it triggers the grant-based transmission through DCI.

[0131] FIG. 12 illustrates a method for a terminal applicable to the present disclosure to operate under sidelink resource allocation mode 2. For example, sidelink resource allocation mode 2 may be a mode in which the terminal directly determines resources for sidelink communication through sensing. Referring to FIG. 12, the terminal may generate sidelink resources (S1201). Specifically, the MAC layer of the terminal may select resources from a resource pool within a sidelink carrier based on sensing and random selection. For example, the physical layer of the terminal may perform an operation based on a sidelink grant received from the MAC layer of the terminal. Furthermore, for example, the MAC layer of the terminal may configure at least one logical channel (LCH), and the terminal may perform retransmissions based on the LCH. If 'sl-HARQ-FeedbackEnabled' is enabled in at least one LCH configured in the terminal, the terminal may determine that a PSFCH is configured in at least one resource pool.

[0132] Referring to FIG. 12, the UE may generate a sidelink grant (S1201). Here, the UE may determine whether to configure multiple MAC PDUs based on the amount of data included in the LCH. For example, the UE may generate a sidelink grant for multiple MAC PDU transmission when data exists in a specific LCH (S1202). Here, the UE may select a resource pool depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S1203). For example, if 'sl-HARQ-FeedbackEnabled' of the LCH is enabled, the UE may select one of the configured resource pools in which a PSFCH is configured as a resource pool (S1204). On the other hand, if 'sl-HARQ-FeedbackEnabled' of the LCH is disabled, the UE may select one of the configured resource pools, regardless of whether a PSFCH is configured (S1204). Thereafter, the UE may perform resource selection (or reselection) in the selected resource pool (S1205). Further, the UE may transmit a sidelink grant to the HARQ entity (S1206). For example, the UE may decide to cancel the generation of a sidelink grant corresponding to multiple MAC PDU transmissions, or may continuously perform a transmission resource selection (or reselection) check operation until the resource pool is released by the RRC. For example, if the UE performs transmission resource reselection based on the transmission resource selection (or reselection) operation, the UE may select a possible value in the 'SL-ResourceReservePeriodList' configured by the RRC as the resource reservation interval (P RVSP_TX The UE may select a resource reservation interval (PDB) in the 'SL-ResourceReservePeriodList' that has a value greater than the remaining packet delay budget (PDB) of the sidelink data.RVSP_TX As an example, in each resource pool, the 'SL-ResourceReservePeriodList' can include up to 16 possible reservation period values. The reservation period value can indicate values ​​of 0, 1 to 99, 100, 200, 300, 400, and 1000 ms, but is not limited thereto. The terminal selects the selected resource reservation period (resource reservation interval, P RVSP_TX If the resource reservation interval (P) is greater than or equal to 100 ms, the UE may randomly select a value between [5, 15] and set it as the sidelink resource reselection counter (SL_RESOURCE_RESELECTION_COUNTER). RVSP_TX ) is less than 100ms, A value between JPEG2025532838000030.jpg22169 can be randomly selected and set as the sidelink resource reselection counter (SL_RESOURCE_RESELECTION_COUNTER).

[0133] Furthermore, the UE can select the number of HARQ retransmissions and frequency resources within the values ​​configured in the RRC parameters. The UE can randomly select time and frequency resources for one transmission opportunity from resources indicated by the physical layer according to the remaining PDB of sidelink data of the LCH and the amount of selected frequency resources. As an example, the UE may allocate the randomly selected resource to a resource reservation interval (P RVSP_TX) can be used to select periodic resources positioned by the PSFCH. Also, if the UE selects one or more HARQ retransmissions, the UE's MAC layer can randomly select resources in consideration of the minimum time gap with the PSFCH in the resource pool, the remaining PDB of sidelink data, and the number of HARQ retransmissions if there are remaining resources indicated by the physical layer. The UE can then use the randomly selected resources as a resource reservation interval (P RVSP_TX ) can be used to select periodic resources located by the resource reservation interval (P RVSP_TX ), the first transmission in the periodically configured resource may be determined as the initial transmission, and subsequent transmissions may be determined as retransmissions.

[0134] As another example, when the UE generates a sidelink grant for single MAC PDU transmission when data exists in a specific LCH (S1203), the UE may select a resource pool depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S1203). That is, when 'sl-HARQ-FeedbackEnabled' of the LCH is enabled, the UE may select one of the configured resource pools in which a PSFCH is configured. Conversely, when 'sl-HARQ-FeedbackEnabled' of the LCH is disabled, the UE may select one resource pool regardless of whether a PSFCH is configured in the configured resource pools.

[0135] As another example, when the UE detects data in a specific LCH and performs sidelink channel state information (CSI) reporting, the UE may select a resource pool depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled. If 'sl-HARQ-FeedbackEnabled' of the LCH is enabled, the UE may select one of the configured resource pools in which a PSFCH is configured as a resource pool. On the other hand, if 'sl-HARQ-FeedbackEnabled' of the LCH is disabled, the UE may select one of the configured resource pools regardless of whether a PSFCH is configured. Here, 'sl-HARQ-FeedbackEnabled' is included in 'SL-LogicalChannelConfig IE' and may be as shown in Table 10 below, but is not limited thereto.

[0136] [Table 10]

[0137] The UE may then perform resource selection (or reselection) in the selected resource pool (S1205). Furthermore, the UE may transmit a sidelink grant to the HARQ entity (S1206). For example, the UE may decide to cancel the generation of a sidelink grant corresponding to a single MAC PDU transmission, or may continuously perform a transmission resource selection (or reselection) check operation until the resource pool is released by RRC. The UE may select the number of HARQ retransmissions and frequency resources within values ​​configured in RRC parameters. Furthermore, the UE may randomly select time and frequency resources for one transmission opportunity from among resources indicated by the physical layer according to the remaining PDB of sidelink data in the LCH, the amount of selected frequency resources, and the latency requirement of SL-CSI. In addition, when one or more HARQ retransmissions are selected by the UE, the UE's MAC layer may randomly select resources, if resources indicated by the UE's physical layer remain, taking into account the minimum time gap with the PSFCH in the resource pool, the remaining PDB of sidelink data, and the number of HARQ retransmissions. For example, if the retransmission resources cannot be selected according to the resources allocated by the previous SCI, the UE may select the retransmission resources in other ways, but is not limited to a specific way.

[0138] FIG. 13 illustrates a sidelink HARQ entity operation method applicable to the present disclosure, and FIG. 14 illustrates a sidelink process. Referring to FIG. 13, a sidelink HARQ entity may receive a sidelink grant from a MAC entity (S1301). For example, the MAC entity of a terminal may perform resource pool selection and resource selection. The sidelink HARQ entity may perform MAC PDU acquisition and transmission decision and sidelink transmission information decision. Furthermore, the sidelink process may refer to instructing a transmission to a physical layer. Here, the MAC entity and the HARQ entity may be separate entities, but they may be logically separated entities and are not limited to a specific form. For convenience of explanation, the following description will be based on the operations performed by the MAC entity and the HARQ entity, but is not limited thereto.

[0139] For example, the sidelink HARQ entity may check whether the sidelink grant is for an initial transmission (S1302). If the sidelink grant is for an initial transmission (S1303), the sidelink HARQ entity may check the associated sidelink process (S1304). Here, if the sidelink HARQ entity does not receive a MAC PDU from the multiplexing and assembly entity (S1305), the sidelink HARQ entity may empty the HARQ buffer of the associated sidelink process (S1306). For example, if a sidelink grant is generated in the MAC entity and a resource pool is selected, the sidelink HARQ entity may ignore the generated sidelink grant if no MAC PDU is delivered from the multiplexing and assembly entity. For example, the UE may perform the above-described operation for periodic resource configuration taking into account a MAC PDU to be generated later, but is not limited thereto.

[0140] On the other hand, when the sidelink HARQ entity receives a MAC PDU from the multiplexing and assembly entity (S1305), it determines sidelink transmission information (S1307). Then, it delivers the MAC PDU, the sidelink grant, and the sidelink transmission information to the sidelink process (S1308). Then, the sidelink HARQ entity instructs the MAC entity of the associated sidelink process to trigger a new transmission (S1309).

[0141] On the other hand, if the sidelink grant is not for an initial connection (S1302), the sidelink HARQ entity can decide to retransmit (S1310). Here, the sidelink HARQ entity checks the associated sidelink process (S1311) and can transmit the sidelink grant to the MAC entity (S1312). The sidelink HARQ entity can then instruct the MAC entity on the associated sidelink process to trigger a new transmission (S1313).

[0142] Further, as an example, referring to FIG. 14, the MAC entity may receive a request from a sidelink HARQ entity (S1401). Here, if the request is for an initial transmission (S1402), the MAC entity may perform the initial transmission (S1403). Further, the MAC entity may store a MAC PDU and a sidelink grant (S1404). Thereafter, the MAC entity may generate a transmission (S1405). For example, the MAC entity may instruct the physical layer to transmit an SCI according to the sidelink transmission information. Furthermore, the MAC entity may instruct the physical layer to transmit the SCI and perform the transmission based on the sidelink transmission information.

[0143] On the other hand, if the request is not a request for the initial transmission (S1402), the MAC entity may perform a retransmission (S1406). Furthermore, the MAC entity may store a sidelink grant (S1407). Thereafter, the MAC entity may generate a transmission (S1405). For example, the MAC entity may instruct the physical layer to transmit an SCI according to the sidelink transmission information. The MAC entity may also instruct the physical layer to transmit the SCI and perform the transmission based on the instructed transmission.

[0144] Also, as an example, sidelink communication can be performed taking into account a situation in which a resource pool is configured for an LBT bandwidth. Specifically, multiple LBT bandwidths (RB sets) can be configured for a wideband. Here, one or more usable resource pools can be configured for each LBT bandwidth. That is, the UE may perform an LBT operation for each LBT bandwidth and select a resource pool based on the LBT operation. For example, if the UE fails an LBT, the UE cannot use the LBT bandwidth and cannot select a resource pool within the LBT bandwidth. Here, the physical layer of the UE may indicate an LBT failure to the MAC layer based on the LBT operation. For example, when the UE performs a sidelink reception and generation procedure, the MAC layer of the UE may need to select a resource pool for attempting sidelink transmission by considering whether the LBT has failed or succeeded from the physical layer of the UE. A method for this will be described below. As an example, the UE operation based on the above-mentioned sidelink resource allocation mode 2 will be described below, but is not limited thereto. That is, the following operation can also be applied to sidelink resource allocation mode 1 and is not limited to a specific embodiment.

[0145] FIG. 15 illustrates a sidelink resource pool configured in an unlicensed single band applicable to the present disclosure. Referring to FIG. 15, an SL BWP may have a 20 MHz bandwidth as a single band. Furthermore, a resource pool may be configured within the SL BWP. As a specific example, referring to FIG. 15(a), resource pools 1510 and 1520 within the SL BWP may be distinguished based on whether or not a PSFCH channel is included. Here, the resource pools 1510 and 1520 within the SL BWP indicate the same resources on the frequency axis but may be distinguished on the time axis. For example, the resource pools 1510 and 1520 within the SL BWP may be distinguished using an 'sl-TimeResource' parameter, and a resource pool 1510 including a PSFCH channel and a resource pool 1520 not including a PSFCH channel may be configured.

[0146] As another example, referring to FIG. 15(b), resource pools 1530 in an SL BWP may be configured with the same resources on the time and frequency axes. Here, resource pools 1530 in an SL BWP may be distinguished based on whether or not a PSFCH channel is present. That is, resource pools 1530 in an SL BWP having the same time and frequency resources may be distinguished based on whether or not a PSFCH channel is present. Here, when the MAC layer of the UE generates a sidelink grant, the MAC layer of the UE may select a resource pool based on whether or not a PSCFH is configured. For example, when HARQ feedback is enabled, the MAC layer of the UE may select resource pool 2 in which a PSFCH is configured. Conversely, when HARQ feedback is disabled, the MAC layer of the UE may select a resource pool regardless of whether or not a PSFCH is configured. Therefore, the UE may select either resource pool 1 or resource pool 2. Here, as an example, when LBT failures occur more than a predetermined number of times in an SL BWP of an unlicensed band, the UE may perform an LBT failure recovery operation. Specifically, the terminal can perform BWP switching in the LBT failure recovery operation. However, when the terminal operates in a single unlicensed band as shown in FIG. 15, the terminal may not be able to perform BWP switching in the LBT failure recovery operation, and the LBT failure operation may be necessary.

[0147] Also, as an example, FIG. 16 illustrates a SL BWP configuration operating in a wideband. Referring to FIG. 16, the SL BWP may have a 40 MHz bandwidth as a wideband. However, this is merely an example and is not limited to this. A resource pool may be configured within the SL BWP. As an example, referring to FIG. 16(a), resource pools 1610, 1620, 1630, 1640, and 1650 may be configured and indicated for each LBT bandwidth (or RB set) within a 40 MHz SL BWP. Here, the presence or absence of a PSFCH channel may be configured differently for each of the resource pools 1610, 1620, 1630, 1640, and 1650. As another example, referring to FIG. 16(b), resource pool 1660 may be configured across two LBT bandwidths (or RB sets) and is not limited to a specific form.

[0148] Furthermore, as an example, resource pools may be configured for each quality of service (QoS) in a specific sidelink communication (e.g., Rel-12 ProSe sidelink). Therefore, a specific QoS can use a specific resource pool. Conversely, resource pools can support all QoS levels allowed in other sidelink communication (e.g., LTE V2X sidelink, NR V2X sidelink). In other words, the QoS of a specific service type can be satisfied in any resource pool regardless of the resource pool selection. Considering the above, one or more resource pools may be configured in a SL BWP, and multiple resource pools may not necessarily be required. Furthermore, as an example, a service type requiring a specific QoS based on a higher layer configuration in other sidelink communication (e.g., LTE V2X sidelink, NR V2X sidelink) may be associated with one or more carrier frequencies.

[0149] For example, when a carrier is selected based on carrier aggregation in other sidelink communications (e.g., LTE V2X Sidelink, NR V2X Sidelink), multiple carriers may be selected as candidate carriers based on packet per packet priority (PPPP). Here, the carrier that is finally selected may be determined as the carrier with the lowest channel busy ratio (CBR) among the candidate carriers. That is, the carrier that is finally selected may be determined as the carrier with the least resource occupancy in the resource pool among the candidate carriers, thereby providing high QoS.

[0150] Referring to FIG. 16, the LBT procedure in unlicensed broadband operation may be performed in units of LBT bandwidths (or RB sets). Here, at least one resource pool may be configured with LBT bandwidths (or RB sets). For example, a terminal may not be able to recognize which LBT bandwidth will result in successful LBT. Therefore, resource pools may be configured to be set and selected for each LBT bandwidth. For example, since access for non-3GPP (e.g., Wi-Fi) coexists in unlicensed bands, channel conditions may vary for each LBT bandwidth.

[0151] Referring to Table 11 below for an existing communication system, the UE can perform resource pool selection by considering only the 'sl-HARQ-FeedbackEnabled' parameter without considering sidelink unlicensed band operation. However, when the UE performs resource pool selection based on the sidelink unlicensed band, the UE needs to perform resource pool selection by considering whether or not an LBT failure has occurred. Specifically, if the UE selects a resource pool in an RB set in which an LBT failure has occurred, the UE cannot occupy the channel, which may result in PSCCH and PSSCH transmission being impossible.

[0152] [Table 11]

[0153] As an example, in FIG. 16(b) above, if the UE succeeds in the LBT only in RB set 0, the UE may not be able to select resource pool 0 (1660) and resource pool 2 (1680). That is, the UE may not select a resource pool in the RB set where the LBT failed, and may need to perform an operation based on that. Therefore, when the UE performs resource pool selection, the UE may take into consideration the matters in Table 12 below. Specifically, the UE may perform resource pool selection based on the LBT result, which will be described later. As another example, the UE may perform resource pool selection based on the LBT failure counter, which will be described later. As another example, the UE may perform RB set and resource pool selection taking CBR into consideration, which will be described later. As another example, the UE may perform resource pool selection taking both the LBT failure counter and CBR into consideration, which will be described later. That is, the UE may select a resource pool taking the LBT result and CBR into consideration.

[0154] [Table 12]

[0155] For example, when the UE MAC layer generates a sidelink grant, the UE MAC layer may select a resource pool taking into account the LBT result or LBT failure counter for each LBT bandwidth (or RB set) configured in the SL BWP. Specifically, FIG. 17 illustrates a resource pool selection procedure applicable to the present disclosure. Referring to FIG. 17, when LCH data requiring HARQ feedback occurs, the UE MAC layer 1710 may perform a procedure for generating a sidelink grant. Here, the UE MAC layer 1710 may instruct the UE physical layer 1720 to perform an LBT check for resource pool selection. The UE physical layer 1720 may perform an LBT operation for each LBT bandwidth (or RB set) configured in the SL BWP and report LBT execution result information to the UE MAC layer 1710.

[0156] As a specific example, when the UE MAC layer 1710 instructs the UE physical layer 1720 to perform an LBT check, the UE MAC layer 1710 may instruct the UE physical layer 1720 to perform an LBT on an LBT bandwidth (or RB set). As another example, the UE MAC layer 1710 may instruct the UE physical layer 1720 to perform an LBT on the entire SL BWP. Furthermore, the LBT result report for each LBT bandwidth (or RB set) reported by the UE physical layer 1720 to the UE MAC layer 1710 may include information on the LBT bandwidth (or RB set) in which an LBT failure occurred. As another example, the LBT result report for each LBT bandwidth (or RB set) may include information on the LBT bandwidth (or RB set) in which an LBT failure does not occur, and is not limited to a specific embodiment.

[0157] As a specific example, when an SL BWP and a resource pool are configured in a UE as shown in FIG. 16(a), data may be generated in an LCH requiring HARQ feedback in the UE. Here, the UE MAC layer 1710 may instruct the UE physical layer 1720 to perform an LBT check for the LBT bandwidth (or RB set) in the SL BWP. The UE physical layer 1720 may report to the UE MAC layer 1710 whether or not an LBT has failed for the LBT bandwidth (or RB set). Here, if an LBT failure occurs in RB set 0, the UE physical layer 1720 may transmit information about RB set 0 in which the LBT failure has occurred to the UE MAC layer 1710. As another example, the UE physical layer 1720 may transmit information about RB set 1 in which no LBT failure occurs to the UE MAC layer 1710, and this is not limited to a specific embodiment. Based on the terminal's physical layer 1710 report, the terminal's MAC layer 1710 can select resource pool 0 (1610) in which the PSFCH is configured in RB set 1, excluding the resource pool in RB set 0 in which the LBT failure occurred.

[0158] Also, as an example, when resource pool selection is performed in the MAC layer of the terminal and HARQ feedback for a specific logical channel is activated, the MAC layer of the terminal may select a resource pool in which a PSFCH is configured, including an LBT bandwidth (or RB set) in which no LBT failure occurs within the configured resource pool.

[0159] As another example, when resource pool selection is performed in the MAC layer of the UE and HARQ feedback for a specific logical channel is activated, the MAC layer of the UE may select a resource pool in which a PSFCH is configured, including an LBT bandwidth (or RB set) in which an LBT failure does not occur within the configured resource pool.As another example, when resource pool selection is performed in the MAC layer of the UE and a specific logical channel is generated by SL-CSI rather than sidelink data, the MAC layer of the UE may select a resource pool in which a PSFCH is configured, including an LBT bandwidth (or RB set) in which an LBT failure does not occur within the configured resource pool.

[0160] That is, the MAC layer of the terminal is associated with multiple configured resource pools and can select a resource pool in which no LBT failure occurs for all LBT bandwidths (or RB sets) in each resource pool.

[0161] Further, as a specific example, the MAC layer of the terminal may instruct the physical layer to perform an LBT operation based on previous sidelink transmissions and other operations to obtain an LBT result. That is, the MAC layer of the terminal may continuously check the LBT result, but is not limited to this. The MAC layer of the terminal may select a resource pool in which no LBT failure occurs among all LBT bandwidths (or RB sets) in each configured resource pool based on the LBT result.

[0162] FIG. 18 illustrates a method for a UE applicable to the present disclosure to perform resource selection taking into account an LBT result. For example, the UE may operate in sidelink resource allocation mode 2, in which the UE directly determines resources for performing sidelink communication through sensing. Referring to FIG. 18, the UE may generate sidelink resources (S1801). For example, when a sidelink grant is received from the UE's MAC layer, the UE's physical layer may perform an operation based on the sidelink grant. The UE's MAC layer may configure at least one LCH, and the LCH may be a unit for performing retransmission. Here, the UE's MAC layer may instruct the UE's physical layer to perform an LBT check for the SL BWP. Referring to FIG. 18, the UE may configure multiple MAC PDUs for data present on the LCH.

[0163] Specifically, when data exists in a specific LCH and the UE generates a sidelink grant for transmitting multiple MAC PDUs (S1802), the UE may select a resource pool depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S1803). For example, when 'sl-HARQ-FeedbackEnabled' of the LCH is enabled, the UE may be associated with an LBT bandwidth (RB set) in which no LBT failure occurs among the configured resource pools, or may select one of the resource pools in which a PSFCH is configured (S1804). On the other hand, when 'sl-HARQ-FeedbackEnabled' of the LCH is disabled, the UE may be associated with an LBT bandwidth (RB set) in which no LBT failure occurs among the configured resource pools, or may select one of the resource pools regardless of whether a PSFCH is configured (S1804). That is, the UE may select a resource pool in an LBT bandwidth (or RB set) in which an LBT failure occurs, taking into account whether HARQ feedback is configured. The UE may then perform resource selection (or reselection) in the selected resource pool (S1805). Furthermore, the UE may transmit a sidelink grant to the HARQ entity (S1806). For example, the UE may decide to cancel the sidelink grant generation corresponding to multiple MAC PDU transmissions, or may continuously perform the transmission resource selection (or reselection) check operation until the resource pool is released by the RRC. For example, when the UE performs transmission resource reselection based on the transmission resource selection (or reselection) operation, the UE may select a possible value in the 'SL-ResourceReservePeriodList' configured by the RRC as the resource reservation interval (P RVSP_TXThe UE may select a resource reservation interval (PDB) in the 'SL-ResourceReservePeriodList' that has a value greater than the remaining packet delay budget (PDB) of the sidelink data. RVSP_TX As an example, in each resource pool, the 'SL-ResourceReservePeriodList' can include up to 16 possible reservation period values. The reservation period value can indicate values ​​of 0, 1 to 99, 100, 200, 300, 400, and 1000 ms, but is not limited thereto. The terminal selects the selected resource reservation period (resource reservation interval, P RVSP_TX If the resource reservation interval (P) is greater than or equal to 100 ms, the UE may randomly select a value between [5, 15] and set it as the sidelink resource reselection counter (SL_RESOURCE_RESELECTION_COUNTER). RVSP_TX ) is less than 100ms, A value between JPEG2025532838000034.jpg19145 can be randomly selected and set as the sidelink resource reselection counter (SL_RESOURCE_RESELECTION_COUNTER).

[0164] Furthermore, the UE can select the number of HARQ retransmissions and frequency resources within the values ​​configured in the RRC parameters. The UE can randomly select time and frequency resources for one transmission opportunity from resources indicated by the physical layer according to the remaining PDB of sidelink data of the LCH and the amount of selected frequency resources. As an example, the UE may allocate the randomly selected resource to a resource reservation interval (P RVSP_TX) can be used to select periodic resources positioned by the PSFCH. Also, if the UE selects one or more HARQ retransmissions, the UE's MAC layer can randomly select resources in consideration of the minimum time gap with the PSFCH in the resource pool, the remaining PDB of sidelink data, and the number of HARQ retransmissions if there are remaining resources indicated by the physical layer. The UE can then use the randomly selected resources as a resource reservation interval (P RVSP_TX ) can be used to select periodic resources located by the resource reservation interval (P RVSP_TX ), the first transmission in the periodically configured resource may be determined as the initial transmission, and subsequent transmissions may be determined as retransmissions.

[0165] As another example, when the terminal generates a sidelink grant for a single MAC PDU transmission when data exists in a specific LCH (S1807), the terminal can select a resource pool associated with an LBT bandwidth (or RB set) in which no LBT failure occurs among the resource pools configured depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S1808).

[0166] For example, when the UE reports sidelink channel state information (CSI) when data exists in a specific LCH, the UE may be associated with an LBT bandwidth (or RB set) in which no LBT failure occurs within a configured resource pool, and may select any of the configured resource pools regardless of whether a PSFCH is configured. The UE then performs resource selection (or reselection) in the selected resource pool (S1805). Furthermore, the UE may transmit a sidelink grant to the HARQ entity (S1806). For example, the UE may decide to cancel the generation of a sidelink grant corresponding to a single MAC PDU transmission, or may continuously perform a transmission resource selection (or reselection) check operation until the resource pool is released by RRC. The UE may select the number of HARQ retransmissions and frequency resources within values ​​configured in RRC parameters. Furthermore, the UE may randomly select time and frequency resources for one transmission opportunity from among resources indicated by the physical layer according to the remaining PDB of sidelink data in the LCH, the amount of selected frequency resources, and the latency requirement of SL-CSI. In addition, when one or more HARQ retransmissions are selected by the UE, the UE's MAC layer may randomly select resources, if resources indicated by the physical layer remain, taking into account the minimum time gap with the PSFCH in the resource pool, the remaining PDB of sidelink data, and the number of HARQ retransmissions. For example, if the retransmission resources cannot be selected according to the resources allocated by the previous SCI, the UE may select the retransmission resources in other ways, but is not limited to a specific way.

[0167] Further, as an example, referring to FIG. 18, a sidelink resource pool may be released or added for each SL BWP based on an identifier (ID). Here, the UE may derive the size of the sidelink resource pool based on the starting RB position of a subchannel in a resource pool configuration associated with the identifier. Furthermore, if the 'intraCellguardBand' parameter is configured in the UE, the UE may determine that multiple RB sets are configured. Therefore, the MAC layer of the UE may receive a report on the presence or absence of LBT failures for multiple RB sets from the physical layer of the UE. Here, the physical layer of the UE may recognize resource pools included in RB sets in which no LBT failure occurs. That is, the physical layer of the UE may implicitly confirm the resource pool configuration without a separate instruction. As another example, the UE may explicitly recognize the association relationship between RB sets associated with a resource pool. As a specific example, when RRC parameters for an SL BWP are configured in the UE, the UE may receive, but is not limited to, an instruction on an associated RB set index in the resource pool configuration.

[0168] 19 is a diagram illustrating a method for selecting a resource pool based on an LBT failure counter applicable to the present disclosure. Referring to FIG. 19, when LCH data requiring HARQ feedback occurs in a UE MAC layer 1910, the UE MAC layer 1910 may generate a sidelink grant and perform resource pool selection. Here, the UE MAC layer 1910 may receive and count LBT results from a UE physical layer 1920 for resource pool selection. As an example, the LBT result may be reported per LBT bandwidth (or RB set) or per resource pool. As another example, the UE physical layer 1920 may report an LBT failure count value to the UE MAC layer 1910 for each LBT bandwidth (or RB set) or per resource pool.

[0169] Further, as an example, the information included in the LBT result report may be information indicating that the LBT failure count does not exceed a preset threshold for each LBT bandwidth (or RB set) or resource pool. That is, if the LBT failure count does not exceed a preset threshold, the UE MAC layer 1910 may receive the LBT result report for each RB set or resource pool from the UE physical layer 1920. As a specific example, a resource pool selection procedure based on the LBT counter may be performed in the procedure for generating a sidelink grant, as shown in FIG. 20. For example, FIG. 20 illustrates a method in which a UE applicable to the present disclosure performs resource selection taking the LBT counter into consideration. The UE may operate in sidelink resource allocation mode 2, in which the UE directly determines resources for performing sidelink communication through sensing. Referring to FIG. 20, the UE may generate sidelink resources (S2001). For example, the UE physical layer may perform an operation based on the sidelink grant received from the UE MAC layer. Further, as an example, the UE MAC layer may configure at least one LCH, and the LCH may be a unit for performing retransmission. Here, the MAC layer of the terminal can instruct the physical layer of the terminal to perform an LBT check for the SL BWP.

[0170] Referring to FIG. 20, the UE may determine whether to configure multiple MAC PDUs by considering data on the LCH. When the UE generates a sidelink grant for transmitting multiple MAC PDUs when data exists on a specific LCH (S2002), the UE may select a resource pool depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S2003). Furthermore, the UE may select a resource pool by comparing the LBT failure counter value with a preset value (or threshold). For example, when 'sl-HARQ-FeedbackEnabled' of the LCH is enabled, the UE may select a resource pool in which a PSFCH is configured from among resource pools or LBT bandwidths (RB sets) having an LBT failure counter value smaller than a preset value (or threshold), and select one of the resource pools. As another example, the UE may select a resource pool in which a PSFCH is configured from among resource pools or LBT bandwidths (RB sets) having an LBT failure counter value smaller than a preset value (or threshold). As another example, if there are multiple resource pools or LBT bandwidths (RB sets) whose LBT failure counters are smaller than a preset value (or threshold), the terminal may select a resource pool or LBT bandwidth (RB set) in different ways, and this is not limited to a specific embodiment (S2004).

[0171] On the other hand, if 'sl-HARQ-FeedbackEnabled' of the corresponding LCH is disabled, the terminal may select one of the resource pools or LBT bandwidths (RB sets) having an LBT failure counter value smaller than a preset value (or threshold), regardless of whether a PSFCH is configured. As another example, the terminal may select one of the resource pools or LBT bandwidths (RB sets) having the smallest LBT failure counter value, regardless of whether a PSFCH is configured, among the resource pools or LBT bandwidths (RB sets) having an LBT failure counter value smaller than a preset value (or threshold). As another example, if there are multiple resource pools or LBT bandwidths (RB sets) having an LBT failure counter smaller than a preset value (or threshold), the terminal may select a resource pool or LBT bandwidth (RB set) in different methods, and the method is not limited to a specific embodiment (S2004).

[0172] The UE may then perform resource selection (or reselection) in the selected resource pool (S2005). Furthermore, the UE may transmit a sidelink grant to the HARQ entity (S2006). For example, the UE may decide to cancel the generation of a sidelink grant corresponding to multiple MAC PDU transmissions, or may continuously perform a transmission resource selection (or reselection) check operation until the resource pool is released by the RRC. For example, when the UE performs transmission resource reselection based on the transmission resource selection (or reselection) operation, the UE may select a possible value in the 'SL-ResourceReservePeriodList' configured by the RRC as the resource reservation interval (P RVSP_TX The UE may select a resource reservation interval (PDB) in the 'SL-ResourceReservePeriodList' that has a value greater than the remaining packet delay budget (PDB) of the sidelink data. RVSP_TXAs an example, in each resource pool, 'SL-ResourceReservePeriodList' can include up to 16 possible reservation period values. The reservation period value can indicate values ​​of 0, 1 to 99, 100, 200, 300, 400, and 1000 ms, but is not limited thereto. The terminal selects the selected resource reservation period (resource reservation interval, P RVSP_TX If the resource reservation interval (P) is greater than or equal to 100 ms, the UE may randomly select a value between [5, 15] and set it as the sidelink resource reselection counter (SL_RESOURCE_RESELECTION_COUNTER). RVSP_TX ) is less than 100ms, A value between JPEG2025532838000035.jpg19145 can be randomly selected and set as the sidelink resource reselection counter (SL_RESOURCE_RESELECTION_COUNTER).

[0173] Furthermore, the UE can select the number of HARQ retransmissions and frequency resources within the values ​​configured in the RRC parameters. The UE can randomly select time and frequency resources for one transmission opportunity from resources indicated by the physical layer according to the remaining PDB of sidelink data of the LCH and the amount of selected frequency resources. As an example, the UE may allocate the randomly selected resource to a resource reservation interval (P RVSP_TX) can be used to select periodic resources positioned by the PSFCH. Also, if the UE selects one or more HARQ retransmissions, the UE's MAC layer can randomly select resources in consideration of the minimum time gap with the PSFCH in the resource pool, the remaining PDB of sidelink data, and the number of HARQ retransmissions if there are remaining resources indicated by the physical layer. The UE can then use the randomly selected resources as a resource reservation interval (P RVSP_TX ) can be used to select periodic resources located by the resource reservation interval (P RVSP_TX ), the first transmission in the periodically configured resource may be determined as the initial transmission, and subsequent transmissions may be determined as retransmissions.

[0174] As another example, when the terminal generates a sidelink grant for a single MAC PDU transmission when data exists in a specific LCH (S2007), the terminal can select a resource pool associated with an LBT bandwidth (or RB set) whose LBT counter is not higher than a threshold among the resource pools configured depending on whether or not 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S2008).

[0175] For example, when the UE reports sidelink channel state information (CSI) when data exists in a specific LCH, the UE may be associated with an RB set in which no LBT failure occurs within a configured resource pool and may select one of the RB sets as the resource pool regardless of whether a PSFCH is configured. The UE then performs resource selection (or reselection) in the selected resource pool (S2005). Furthermore, the UE may transmit a sidelink grant to the HARQ entity (S2006). For example, the UE may decide to cancel the generation of a sidelink grant corresponding to a single MAC PDU transmission, or may continuously perform a transmission resource selection (or reselection) check operation until the resource pool is released by RRC. The UE may select the number of HARQ retransmissions and frequency resources within values ​​configured in RRC parameters. Furthermore, the UE may randomly select time and frequency resources for one transmission opportunity from among resources indicated by the physical layer according to the remaining PDB of sidelink data in the LCH, the amount of selected frequency resources, and the latency requirement of SL-CSI. In addition, when one or more HARQ retransmissions are selected by the UE, the UE's MAC layer may randomly select resources, if resources indicated by the physical layer remain, taking into account the minimum time gap with the PSFCH in the resource pool, the remaining PDB of sidelink data, and the number of HARQ retransmissions. For example, if the retransmission resources cannot be selected according to the resources allocated by the previous SCI, the UE may select the retransmission resources in other ways, but is not limited to a specific way.

[0176] Further, as an example, referring to FIG. 20, a sidelink resource pool may be released or added for each SL BWP based on an identifier (ID). Here, the UE may derive the size of the sidelink resource pool based on the starting RB position of a subchannel in a resource pool configuration associated with the identifier. Also, if the 'intraCellguardBand' parameter is configured in the UE, the UE may determine that multiple LBT bandwidths (RB sets) are configured. Therefore, the MAC layer of the UE may receive a report on the presence or absence of LBT failures for multiple LBT bandwidths (RB sets) from the physical layer of the UE. Here, the physical layer of the UE may recognize resource pools included in LBT bandwidths (RB sets) where no LBT failure occurs. That is, the physical layer of the UE may implicitly confirm the resource pool configuration without a separate instruction. As another example, the UE may explicitly recognize the association of LBT bandwidths (RB sets) associated with a resource pool. As a specific example, when configuring RRC parameters for BWP in a terminal, the terminal may receive an indication of the associated LBT bandwidth (RB set) index in the resource pool configuration, but is not limited to this.

[0177] FIG. 21 illustrates a method for generating a sidelink grant and selecting resources based on a CBR to which the present disclosure is applicable. Referring to FIG. 21, data may be generated at time n. The UE may generate a sidelink grant and perform resource selection for the generated data transmission. For example, when the UE generates a sidelink grant, the UE may select a CR limit, the number of retransmission resources, the number of selectable subchannels, the range of selectable modulation coding scheme (MCS) levels, and the transmission power based on the CBR range. The UE may generate the sidelink grant by taking the above parameters into consideration. That is, the UE may perform RB set and resource pool selection by taking the above parameters into consideration, thereby generating the sidelink grant without additional delay.

[0178] FIG. 22 illustrates a CBR window in a sidelink unlicensed band applicable to the present disclosure. Referring to FIG. 22, CBR windows 2210 and 2220 may be configured for each resource pool. As an example, in FIG. 22, CBR windows 2210 and 2220 may be configured for each RB set in the sidelink unlicensed band. Specifically, CBR window 1 (2210) may be configured corresponding to resource pool 0 and resource pool 1 (RP0, RP1, 2230, 2240). Furthermore, CBR window 2 (2220) may be configured corresponding to resource pool 2 and resource pool 3 (RP2, RP3, 2250, 2260). As an example, in FIG. 22, the CBR window is expressed as the same in resource pools located in the same LBT bandwidth (RB set), but this is not limited to an example. That is, the CBR window may be configured differently for each resource pool. As a specific example, the CBR window size may be configured to be the same for resource pools included in the same LBT bandwidth (RB set), but the RSSI thresholds may be set to be different. As another example, the CBR window size may be configured to be different for each resource pool in consideration of the characteristics of the sidelink unlicensed band, and is not limited to a specific form.

[0179] As an example, when sidelink data occurs on an LCH with 'sl-HARQ-FeedbackEnabled' enabled, the UE may determine resource pool 0 (2230) and resource pool 2 (2250) in which a PSFCH is configured in the SL BWP as candidate resource pools. The UE may check the CBRs for resource pool 0 (2230) and resource pool 2 (2250), which are candidate resource pools, and may select a resource pool having a smaller CBR than a preset value (or threshold) as the final resource pool. As another example, the UE may check the CBRs for resource pool 0 (2230) and resource pool 2 (2250), which are candidate resource pools, and may compare the CBRs to select a resource pool having a smaller CBR as the final resource pool.

[0180] On the other hand, when sidelink data occurs on an LCH for which 'sl-HARQ-FeedbackEnabled' is disabled, the UE may determine resource pool 0 (2220), resource pool 1 (2230), resource pool 2 (2240), and resource pool 3 (2250) as candidate resource pools from all resource pools, regardless of whether a PSFCH is configured in the SL BWP. The UE may check the CBR for each of the candidate resource pools, resource pool 0 (2220), resource pool 1 (2230), resource pool 2 (2240), and resource pool 3 (2250), and select a resource pool having a CBR smaller than a preset value (or threshold) as the final resource pool. As another example, the UE may check the CBR for each of the candidate resource pools, resource pool 0 (2220), resource pool 1 (2230), resource pool 2 (2240), and resource pool 3 (2250), and compare the CBRs to select the resource pool having the smallest CBR as the final resource pool. As another example, a terminal may configure multiple final resource pools, and is not limited to a specific form.

[0181] Further, as an example, a sidelink resource pool may be released or added for each SL BWP based on an identifier (ID). Here, the UE may derive the size of the sidelink resource pool based on the starting RB position of a subchannel in a resource pool configuration associated with the identifier. Also, if the 'intraCellguardBand' parameter is configured in the UE, the UE may determine that multiple LBT bandwidths (RB sets) are configured. Therefore, the MAC layer of the UE may receive a report on the presence or absence of LBT failures for multiple LBT bandwidths (RB sets) from the physical layer of the UE. Here, the physical layer of the UE may recognize a resource pool included in an LBT bandwidth (RB set) where no LBT failure occurs. That is, the physical layer of the UE may implicitly confirm the resource pool configuration without a separate instruction. As another example, the UE may explicitly recognize the association relationship with the RB set associated with the resource pool. As a specific example, when the UE configures RRC parameters for the BWP, the UE may receive, but is not limited to, an instruction on an associated RB set index in the resource pool configuration.

[0182] As another example, the terminal may select a final resource pool taking into consideration both the LBT failure counter and the CBR. Specifically, the terminal may select a resource pool whose CBR is smaller than a preset value (or threshold). Here, if there are multiple resource pools selected by the terminal, the terminal may select a final resource pool based on the LBT failure counter. As another example, the terminal may select a resource pool whose LBT failure counter is smaller than a preset value (or threshold). Here, if there are multiple resource pools selected by the terminal, the terminal may select a final resource pool according to the CBR.

[0183] For example, as described above, when the MAC layer of the UE generates a sidelink grant, the MAC layer of the UE may instruct the physical layer of the UE to perform an LBT check. The physical layer of the UE may perform the LBT and report the result to the MAC layer of the UE. Here, the time when the LBT result is confirmed for resource pool selection may differ from the time when the actual SCI and data are transmitted. Therefore, the physical layer of the UE may need to perform additional operations when performing an additional LBT procedure. As another example, the UE may select one resource pool taking into account at least one of the LBT failure counter value and the CBR, as described above. However, there is a possibility that the LBT may fail when the UE transmits the SCI and data, which may result in a transmission failure.

[0184] Considering the above, the UE may select one or more candidate resource pools. The UE may perform resource selection in one or more resource pools and perform SCI and data transmission through the selected resources. As a specific example, the UE's MAC layer may determine a resource pool included in an RB set where LBT was successful among the candidate resource pools as the final resource pool and instruct the UE's physical layer to perform transmission. As an example, FIG. 23 illustrates a resource pool configuration in an SL BWP applicable to the present disclosure. Referring to FIG. 23, an SL BWP of an unlicensed band may be configured in the UE. Here, the SL BWP may include one or more LBT bandwidths (or RB sets) for wideband operation, and one or more resource pools may be configured for the LBT bandwidth (or RB set). As an example, in FIG. 23, each of the resource pools 2310, 2320, 2330, and 2340 may be differentiated by index and configured in the UE. Furthermore, each of the resource pools 2310, 2320, 2330, and 2340 may differ in whether or not resources for HARQ feedback are configured. For example, a resource pool in which resources for HARQ feedback are configured may be represented as w / PSFCH (with PSFCH), and a resource pool in which resources for HARQ feedback are not configured may be represented as w / o PSFCH (without PSFCH). Here, the PSFCH resource may be periodically configured with logical sidelink slots. As a specific example, if the PSFCH resource period is configured with four slots, the PSFCH resource may be configured with the slot of "Sidelink slot index mod 4=0" based on the logical sidelink slot. The UE may select one or more candidate resource pools instead of one resource pool, thereby operating while taking into account LBT failure. For example, the UE may select a resource pool in which PSFCH resources for data transmission are configured on an LCH in which HARQ feedback is activated as a candidate resource pool. Here, the UE may select one or more candidate resource pools for each LBT bandwidth (or RB set).23, when HARQ feedback is enabled, the candidate resource pools may be resource pool 0 (2310), resource pool 2 (2330), and resource pool 3 (2340). On the other hand, when HARQ feedback is disabled, the candidate resource pools may be resource pool 0 (2310), resource pool 1 (2320), resource pool 2 (2330), and resource pool 3 (2340). That is, when HARQ feedback is disabled, the terminal can select a resource pool regardless of whether a PSFCH is configured or not.

[0185] Here, when the UE configures one or more resource pools in units of LBT bandwidth (or RB set), the following may be shown in Table 13. Specifically, when HARQ feedback is enabled, the UE may select resource pool 2 (2330) as a candidate resource pool for RB set 0, select resource pool 0 (2310) as a candidate resource pool for RB set 1, and select resource pool 3 as a candidate resource pool for RB sets 0 and 1. On the other hand, when HARQ feedback is disabled, the UE may select resource pool 2 (2330) as a candidate resource pool for RB set 0, select resource pool 0 (2310) or resource pool 1 (2320) as a candidate resource pool for RB set 1, and select resource pool 3 (2340) as a candidate resource pool for RB sets 0 and 1.

[0186] [Table 13]

[0187] For example, in FIG. 23, the resource pool configured for RB set 0 is resource pool 2 (2330) in which HARQ feedback resources are configured, so resource pool 2 (2330) can be selected regardless of whether HARQ feedback for the LCH is enabled or disabled. On the other hand, resource pools configured for RB set 1 may include resource pool 0 (2310) in which HARQ feedback resources are configured and resource pool 1 (2320) in which HARQ feedback resources are not configured. Therefore, if HARQ feedback for the LCH is enabled, the UE may select resource pool 0 (2310) as a candidate resource pool. On the other hand, if HARQ feedback for the LCH is disabled, the UE may select resource pool 0 (2310) or resource pool 1 (2320) as a candidate resource pool. Furthermore, if the UE succeeds in LBT in both RB set 0 and RB set 1 and channel occupancy is possible, the UE may select resource pool 32340 configured for wideband operation as a candidate resource pool.

[0188] FIG. 24 illustrates a method for a UE applicable to the present disclosure to perform resource selection taking into account an LBT counter. For example, the UE may operate in sidelink resource allocation mode 2, in which the UE directly determines resources for performing sidelink communication through sensing. Referring to FIG. 24, the UE may generate sidelink resources (S2401). For example, when a sidelink grant is received from the UE's MAC layer, the UE's physical layer may perform an operation based on the sidelink grant. Further, for example, the UE's MAC layer may configure at least one LCH, and the LCH may be a unit for performing retransmissions. Here, the UE's MAC layer may instruct the UE's physical layer to perform an LBT check for the SL BWP.

[0189] Referring to FIG. 24, the UE may determine whether to construct multiple MAC PDUs based on data of an LCH. When the UE generates a sidelink grant for transmitting multiple MAC PDUs when data exists in a specific LCH (S2402), the UE may select a resource pool depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S2403). Furthermore, the UE may perform resource pool selection in consideration of candidate resource pools. For example, if 'sl-HARQ-FeedbackEnabled' of the LCH is enabled, the UE may select candidate resource pools based on whether HARQ feedback is enabled (S2404) and perform transmission resource selection in each candidate resource pool (S2405). On the other hand, if 'sl-HARQ-FeedbackEnabled' of the LCH is disabled, the UE may select candidate resource pools based on whether HARQ feedback is disabled (S2404) and perform transmission resource selection in each candidate resource pool (S2405). Furthermore, the terminal may transmit a sidelink grant to the HARQ entity (S2406).

[0190] For example, if the UE generates a sidelink grant for a single MAC PDU transmission when data exists in a specific LCH (S2407), the UE may select a resource pool depending on whether 'sl-HARQ-FeedbackEnabled' of the LCH is enabled (S2408). For example, if 'sl-HARQ-FeedbackEnabled' of the LCH is enabled, the UE may select candidate resource pools based on HARQ feedback enable and perform transmission resource selection in each candidate resource pool (S2405). Conversely, if 'sl-HARQ-FeedbackEnabled' of the LCH is disabled, the UE may select candidate resource pools based on HARQ feedback disable and perform transmission resource selection in each candidate resource pool (S2405). Furthermore, the UE may transmit the sidelink grant to the HARQ entity (S2406).

[0191] FIG. 25 illustrates a sidelink operation to which the present disclosure can be applied. The UE MAC layer may select a final resource pool excluding a resource pool within the LBT bandwidth (or RB set) where an LBT failure occurs. That is, the MAC layer may select a resource pool within the LBT bandwidth (or RB set) where the LBT was successful. Then, the UE MAC layer may instruct the UE physical layer to transmit SCI and data through the selected resource pool. For example, if an LBT failure does not occur only in RB set 0, the UE MAC layer may select one of the resource pools included in RB set 0. Conversely, if an LBT failure does not occur only in RB set 1, the UE MAC layer may select one of the resource pools included in RB set 1. As another example, if an LBT failure does not occur in both RB set 0 and RB set 1, the UE MAC layer may select one of all candidate resource pools. As a specific example, referring to FIG. 25, the UE MAC layer may receive a transmission request from a sidelink HARQ entity (S2501). Here, the MAC layer of the terminal may determine whether the requested transmission is an initial transmission (S2502). For example, if the requested transmission is an initial transmission (S2503), the MAC layer of the terminal may store the MAC PDU and the sidelink grant (S2504) and perform an LBT check in the SL BWP (S2505). Then, the MAC layer of the terminal may select a resource pool within the LBT bandwidth (or RB set) where the LBT was successful (S2506) and perform transmission (S2507). Here, the MAC layer of the terminal may instruct the physical layer of the terminal to transmit an SCI based on the sidelink transmission information. Furthermore, the MAC layer of the terminal may instruct the physical layer of the terminal to generate a transmission.

[0192] On the other hand, if the requested transmission is not an initial transmission (S2508), the UE MAC layer may perform retransmission (S2508). Then, the UE MAC layer stores the sidelink grant (S2509) and may perform an LBT check in the SL BWP (S2510). Then, the UE MAC layer may perform transmission based on the success of the LBT (S2507). Here, the UE MAC layer may instruct the UE physical layer to transmit an SCI based on the sidelink transmission information. Furthermore, the UE MAC layer may instruct the UE physical layer to generate a transmission.

[0193] As another example, FIG. 26 illustrates an SL BWP including multiple RB sets. Referring to FIG. 26, a resource pool configuration in the SL BWP may be configured to always include multiple LBT bandwidths (or RB sets). However, this is merely an example and is not limiting. For example, even when the resource pool 2610 includes multiple LBT bandwidths (or RB sets), the UE may select a resource pool based on whether HARQ feedback for the LCH is enabled / disabled, as described above. However, when the resource pool 2610 includes multiple LBT bandwidths (or RB sets), the UE's operation of selecting a transmission opportunity for initial transmission (or retransmission) may become problematic. Specifically, after selecting a resource pool, the UE may randomly select a transmission opportunity for initial transmission (or retransmission) from among resource sets (or resources) indicated by the UE's physical layer. For example, the UE may implicitly recognize which LBT bandwidth (or RB set) the resource belongs to, but may select a transmission opportunity without considering whether the LBT is successful. Therefore, if the UE randomly selects resources on which the LBT is not successful, the UE cannot perform transmission even if it randomly selects resources in the resource pool. As a specific example, in FIG. 26, resource pool 0 (2610) may include two LBT bandwidths (or RB sets). The UE may select resource pool 0 (2610) and randomly select resource sets (or resources) included in the two LBT bandwidths (or RB sets). Here, if the UE selects resource pool 0 (2610) and randomly selects resources included in RB set 0 to determine a transmission opportunity, the UE cannot perform transmission unless the LBT is successful in RB set 0. As an example, if the LBT fails in RB set 0 but is successful in RB set 1, the UE needs to select resources in RB set 1 rather than RB set 0 to perform transmission. That is, the UE needs to perform transmission opportunity selection taking into account LBT-related information.Specifically, the UE can perform transmission opportunity selection by taking into account the LBT result, the LBT counter, and candidate transmission opportunities for each RB set (or LBT bandwidth), which will now be described.

[0194] As an example, FIG. 27 illustrates a method for selecting a transmission opportunity based on candidate transmission opportunities applicable to the present disclosure. Referring to FIG. 27, when a terminal selects a transmission opportunity, the terminal may select available candidate resources 2710 and 2720 for each LBT bandwidth (or RB set). As a specific example, when the terminal performs SCI and data transmission, the terminal's MAC layer may receive an LBT result report from the terminal's physical layer and determine which of the candidate resources to use for actual transmission. As an example, in FIG. 27, if the LBT fails in RB set 1 but is successful in RB set 0, the terminal may determine candidate transmission resource 1 (2710) as a transmission opportunity. Conversely, if the LBT fails in RB set 0 but is successful in RB set 1, the terminal may determine candidate transmission resource 2 (2720) as a transmission opportunity. As another example, if the LBT is successful in both RB set 0 and RB set 1, the terminal may determine either candidate transmission resource 1 (2710) or candidate transmission resource 2 (2720) as a transmission opportunity.

[0195] That is, if the UE succeeds in LBT in only one LBT bandwidth (or RB set), the UE may determine a candidate resource in the RB set where the LBT was successful as a transmission opportunity. Conversely, if the UE succeeds in LBT in multiple LBT bandwidths (or RB sets), the UE may determine one of the candidate resources as a transmission opportunity. Here, as an example, if the UE can check the LBT counter value in the LBT bandwidth (or RB set), the UE may select a resource in the RB set with a small LBT counter value, but this is not limiting.

[0196] As another example, the UE may set candidate resources for an LBT bandwidth (or RB set). As described above, candidate resources may be determined for each LBT bandwidth (or RB set), or candidate resources for multiple LBT bandwidths (or RB sets) may also be determined. If the UE succeeds in LBT for all of the multiple LBT bandwidths (or RB sets), the UE may determine candidate resources for the multiple LBT bandwidths (or RB sets) as transmission opportunities, but this is not limiting.

[0197] FIG. 28 is a diagram illustrating a method for determining a transmission opportunity based on an LBT operation applicable to the present disclosure. Referring to FIG. 28, a UE may determine a transmission opportunity based on an LBT. As a specific example, referring to FIG. 28(a), a UE MAC layer 2810 may select a transmission opportunity based on an LBT result. The UE MAC layer 2810 may request an LBT check from the UE physical layer 2820 and may receive a report of the LBT result for each RB set based on the LBT check. Here, the UE MAC layer 2810 may select resources within an LBT bandwidth (or RB set) in which the LBT was successful. For example, as shown in FIG. 26, when a UE is configured with a single resource pool in an SL BWP including multiple LBT bandwidths (or RB sets), when selecting a transmission opportunity, the UE MAC layer may perform transmission opportunity selection based on the LBT result reported by the UE physical layer. For example, if an LBT success is reported for RB set 0 and an LBT failure is reported for RB set 1, the UE MAC layer 2810 may select a transmission opportunity within RB set 0.

[0198] Further, as an example, referring to FIG. 28(b), the UE MAC layer 2810 may select a transmission opportunity based on an LBT counter value. For example, the UE physical layer 2820 may continuously report an LBT result for each LBT bandwidth (or RB set) to the UE MAC layer 2810. Here, the UE MAC layer 2810 may select a transmission opportunity based on the LBT counter value reported for each LBT bandwidth (or RB set). For example, as shown in FIG. 26, when a UE selects a transmission opportunity in a case where one resource pool is configured in an SL BWP including multiple RB sets, the UE MAC layer may perform transmission opportunity selection based on the LBT result reported from the UE physical layer through an LBT failure counter value. For example, if the LBT counter value for RB set 0 is smaller than the LBT counter value for RB set 1, the UE MAC layer 2810 may select a transmission opportunity within RB set 0.

[0199] As another example, the UE may select a HARQ retransmission resource from a resource pool in which a PSFCH resource is configured. Here, the UE may need to ensure a minimum time gap between the two selected resources to take into account the processing time for HARQ feedback transmission and reception. As an example, the minimum time gap may be as shown in Table 14 below. Here, a maximum channel occupancy time (MCOT) restriction may be set for the sidelink unlicensed band. That is, the UE may perform sidelink communication based on the MCOT within a limited time period considering the use of the unlicensed band. Here, the UE may not be able to perform HARQ feedback transmission and reception due to the MCOT restriction, and therefore may need to schedule consecutive sidelink slots taking this into account. In consideration of the above, the UE may select resources without considering the minimum time gap, which will be described below.

[0200] [Table 14]

[0201] For example, the UE MAC layer may select one or more HARQ retransmission counts. Here, if there are available resources remaining in the resource pool among the resources indicated by the UE physical layer, the UE MAC layer may select resources taking into consideration the destination UE's sidelink DRX activation time (destination UE SL DRX active time), the amount of frequency resources, the number of retransmission resources, the remaining PDB of LCH data, and the SL-SCI latency requirement. For example, when the UE MAC layer selects resources, the aforementioned minimum time gap between two selected resources may be guaranteed, as shown in FIG. 29. For example, FIG. 29 may be a diagram illustrating a case where a minimum time gap is guaranteed in a transmission opportunity applicable to the present disclosure. Referring to FIG. 29, a minimum time gap may be set between each transmission opportunity 2910, 2920, and 2930, taking into consideration the processing time for transmission and reception. Here, the selected resources may be determined as transmission opportunities. For example, the first resource may be determined as an initial transmission opportunity, and the remaining resources may be determined as retransmission opportunities. Furthermore, all transmission opportunities may be determined as selected sidelink grants. For example, if an inter-UE coordination function is activated in the UE, the UE MAC layer may select resources within the preferred resource set and the resource set indicated by the physical layer.

[0202] For example, the retransmission resource may be indicated through a time resource assignment in the 1st SCI, and may be represented by 5 bits if sl-MaxNumperReserve, an upper layer parameter indicating the number of retransmission resources, is 2. For example, if sl-MaxNumperReserve, an upper layer parameter indicating the number of retransmission resources, is 3, the retransmission resource may be represented by 9 bits. For example, if sl-MaxNumperReserve is 3, up to 3 transmission opportunities may be configured, and the logical sidelink slot position and subchannel position starting from each transmission opportunity may be determined and indicated by the TRIV indicated in the time resource assignment and the FRIV indicated in the frequency resource assignment.

[0203] On the other hand, the aforementioned MCOT may exist in an unlicensed band. For example, if there are two selected resources, the two resources may be limited to be selected while ensuring a minimum time gap within the MCOT. In consideration of the above, transmission opportunities for the two selected resources may be determined as consecutive slots. Specifically, FIG. 30 illustrates a method for determining transmission opportunities for consecutive slots in an unlicensed band, which is applicable to the present disclosure. Referring to FIG. 30, transmission opportunities 3010, 3020, and 3030 may be determined as consecutive slots. A terminal may select one or more retransmissions and may select available resources from among resources indicated by the physical layer when selecting each resource. Here, the terminal may not guarantee a minimum time gap between the two selected resources. For example, the first resource selected by the terminal may be determined as an initial transmission opportunity, and the remaining resources may be determined as retransmission opportunities. Furthermore, for example, the selected resources may be limited to resources within the MCOT. That is, when a terminal occupies a channel through an LBT procedure, the terminal may select a transmission opportunity taking into account the maximum time it can occupy the channel (MCOT). As described above, even in a resource pool in which PSFCH resources are configured, retransmission resources can be selected without satisfying the minimum time gap.

[0204] FIG. 31 is a flowchart showing a method for a terminal to which the present disclosure can be applied to perform sidelink communication. Referring to FIG. 31, the terminal may receive sidelink resource pool configuration information from a base station based on higher layer signaling. Here, the terminal may generate a sidelink grant when data is generated on an LCH based on the sidelink resource pool configuration information (S3110). Here, if HARQ feedback is configured for the data generated on the LCH based on the sidelink resource pool configuration information (S3120), the terminal may select a sidelink resource pool in which a PSFCH is configured based on at least one of an LBT result, an LBT failure counter, and a CBR (S3130). The terminal then selects sidelink resources from the selected sidelink resource pool to perform sidelink transmission (S3140). On the other hand, if HARQ feedback is not configured for the data generated on the LCH based on the sidelink resource pool configuration information (S3120), the terminal may select a sidelink resource pool regardless of the PSFCH configuration based on at least one of an LBT result, an LBT failure counter, and a CBR (S3150). Then, the terminal selects a sidelink resource from the selected sidelink resource pool and performs sidelink transmission (S3140).

[0205] Here, as an example, the UE may select a resource pool from at least one sidelink resource pool included in an LBT bandwidth in which the LBT succeeds and occupies a channel based on the LBT result, as described above. As another example, the UE may select a sidelink resource pool from at least one sidelink resource pool included in an LBT bandwidth in which the LBT counter is smaller than a preset value based on the LBT counter, as described above.

[0206] FIG. 32 illustrates a method for a terminal applicable to the present disclosure to perform sidelink communication. Referring to FIG. 32, the terminal may generate a sidelink grant based on data generated in an LCH (S3210). For example, if a sidelink resource pool including multiple LBT bandwidths is configured in the terminal based on sidelink resource pool configuration information (S3220), the terminal may configure candidate transmission opportunities within the sidelink resource pool based on the LBT bandwidths (S3230). For example, but not limited to, candidate transmission opportunities may be configured for each LBT bandwidth. The terminal may then select a sidelink resource pool including multiple LBT bandwidths based on at least one of an LBT result, an LBT failure counter, and a CBR. Here, the terminal may select a specific transmission opportunity from the candidate transmission opportunities based on at least one of the LBT result, the LBT failure counter, and a CBR (S3240). On the other hand, if a sidelink resource pool including one LBT bandwidth is configured in the terminal (S3220), the terminal can select a sidelink resource pool based on at least one of the LBT result, the LBT failure counter, and the CBR, and randomly select a transmission opportunity from the selected sidelink resource pool, as described above (S3250).

[0207] FIG. 33 is a diagram showing a base station apparatus and a terminal apparatus to which the present disclosure can be applied.

[0208] The base station device 3300 may include a processor 3320 , an antenna unit 3312 , a transceiver 3214 , and a memory 3316 .

[0209] The processor 3320 performs baseband-related signal processing and may include an upper layer processing unit 3330 and a physical layer processing unit 3340. The upper layer processing unit 3330 may process operations of a Medium Access Control (MAC) layer, a Radio Resource Control (RRC) layer, or higher layers. The physical layer processing unit 3340 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 3320 may control the overall operation of the base station device 3300.

[0210] The antenna unit 3312 may include one or more physical antennas, and when multiple antennas are included, it may support MIMO (Multiple Input Multiple Output) transmission and reception, and may also support beamforming.

[0211] The memory 3316 can store information processed by the processor 3320, software associated with the operation of the base station device 3300, an operating system, applications, etc., and can include components such as buffers.

[0212] The processor 3320 of the base station device 3300 may be configured to perform the operations of the base station in the embodiments described herein.

[0213] The terminal device 3350 may include a processor 3370, an antenna unit 3362, a transceiver 3364, and a memory 3366. As an example, in the present invention, the terminal device 3350 can communicate with the base station device 3300. As another example, in the present invention, the terminal device 3350 can perform sidelink communication with another terminal device. That is, the terminal device 3350 of the present invention refers to a device that can communicate with at least one of the base station device 3300 and another terminal device, and is not limited to communication with a specific device.

[0214] The processor 3370 performs baseband-related signal processing and may include an upper layer processing unit 3380 and a physical layer processing unit 3390. The upper layer processing unit 3380 may process operations of the MAC layer, the RRC layer, or higher layers. The physical layer processing unit 3390 may process operations of the PHY layer (e.g., downlink receive signal processing, uplink transmit signal processing). In addition to performing baseband-related signal processing, the processor 3370 may control the overall operation of the terminal device 3350.

[0215] The antenna unit 3362 may include one or more physical antennas, and when multiple antennas are included, may support MIMO transmission and reception, and may also support beamforming.

[0216] The memory 3366 can store information processed by the processor 3370, software associated with the operation of the terminal device 3350, an operating system, applications, etc., and can include components such as buffers.

[0217] A terminal device 3350 according to an embodiment of the present invention may be associated with a vehicle. For example, the terminal device 3350 may be built into, located in, or located on the vehicle. The terminal device 3350 according to the present invention may be the vehicle itself. The terminal device 3350 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 3350 to which the present invention is applicable 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 hazard diagnosis. The terminal device 3350 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.

[0218] Here, vehicles to which the present invention is applied may include autonomous vehicles, semi-autonomous vehicles, non-autonomous vehicles, etc. Meanwhile, although the terminal device 3350 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 construed as being limited by the described example.

[0219] In addition, the terminal device 3350 according to an embodiment of the present invention may include various types of communication devices that can cooperate to support an interactive service using a sidelink. That is, the terminal device 3350 can be used not only to directly support an interactive service using a sidelink, but also as a cooperating device to support an interactive service using a sidelink.

[0220] As an example, the terminal device 3350 may receive sidelink resource pool configuration information from the base station device 3300 based on higher layer signaling. Here, the terminal device 3350 may generate a sidelink grant when data is generated on the LCH based on the sidelink resource pool configuration information. Here, if HARQ feedback is configured for the data generated on the LCH based on the sidelink resource pool configuration information, the terminal device 3350 may select a sidelink resource pool in which a PSFCH is configured based on at least one of the LBT result, the LBT failure counter, and the CBR. Then, the terminal device 3350 may select sidelink resources from the selected sidelink resource pool to perform sidelink transmission. On the other hand, if HARQ feedback is not configured for the data generated on the LCH based on the sidelink resource pool configuration information, the terminal device 3350 may select a sidelink resource pool regardless of the PSFCH configuration based on at least one of the LBT result, the LBT failure counter, and the CBR. Then, the terminal device 3350 may select sidelink resources from the selected sidelink resource pool to perform sidelink transmission. Also, as an example, if a sidelink resource pool including multiple LBT bandwidths is configured in the terminal device 3350 based on the sidelink resource pool configuration information, the terminal device 3350 can configure candidate transmission opportunities in the sidelink resource pool based on the LBT bandwidth. Then, the terminal device 3350 can select a sidelink resource pool including multiple LBT bandwidths based on at least one of the LBT result, the LBT failure counter, and the CBR. Here, the terminal can select a specific transmission opportunity from the candidate transmission opportunities based on at least one of the LBT result, the LBT failure counter, and the CBR.

[0221] 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.

[0222] 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.

[0223] 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]

[0224] The above may also be applied to other systems.

Claims

1. A method for a terminal to perform unlicensed spectrum sidelink communication in a wireless communication system, comprising: receiving sidelink resource pool configuration information from the base station based on higher layer signaling by the terminal; generating a sidelink grant (SL grant) when data is generated on a logical channel (LCH) based on the sidelink resource pool configuration information; selecting a sidelink resource pool depending on whether hybrid automatic repeat and request (HARQ) feedback is configured for data generated on the LCH based on the sidelink resource pool configuration information; and selecting sidelink resources from the selected sidelink resource pool to perform sidelink transmission; The terminal performs a listen before talk (LBT) operation of the unlicensed band during the process of selecting the sidelink resource pool, The sidelink resource pool selection is performed based on at least one of an LBT result, an LBT failure counter, and a CBR (channel busy ratio).

2. If the HARQ feedback is configured in the terminal, the terminal selects the sidelink resource pool from at least one sidelink resource pool in which a physical sidelink feedback channel (PSFCH) is configured; 2. The sidelink communication method of claim 1, wherein, if the HARQ feedback is not configured in the terminal, the terminal selects the sidelink resource pool from at least one sidelink resource pool regardless of whether a PSFCH configuration is present.

3. The sidelink communication method according to claim 2, wherein the terminal selects the resource pool from among at least one resource pool included in an LBT bandwidth in which the LBT was successful based on the LBT result.

4. The sidelink communication method according to claim 3, wherein the terminal selects the resource pool from among at least one resource pool included in an LBT bandwidth whose LBT counter is smaller than a preset value based on the LBT counter.

5. When a first sidelink resource pool including a plurality of LBT bandwidths is configured in the terminal, at least one candidate transmission opportunity is configured in the first sidelink resource pool including the plurality of LBT bandwidths based on each LBT bandwidth; 2. The sidelink communication method according to claim 1, wherein, when the first sidelink resource pool is selected based on at least one of the LBT result, the LBT failure counter, and the CBR, the terminal selects a first transmission opportunity from among the at least one candidate transmission opportunity in the first sidelink resource pool based on at least one of the LBT result, the LBT failure counter, and the CBR.

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