Method and apparatus for performing sidelink communication in unlicensed band

Abstract

A method of performing sidelink communication in an unlicensed frequency band may include: determining an entire resource element (RE) for a physical sidelink shared channel (PSSCH); and determining a transport block size (TBS) based on the entire RE.

Description

Technical Field

[0001] The present disclosure proposes a rate matching method for New Radio (NR) sidelink-unlicensed (SL-U) data channel transmission and reception in an unlicensed band. Background Art

[0003] The International Telecommunication Union (ITU) has developed the International Mobile Telecommunications (IMT) framework and standards. Likewise, ongoing discussions on 5th generation (5G) communications are ongoing through a process called “IMT for 2020 and beyond”.

[0004] In order to meet the requirements requested by "IMT for 2020 and beyond", various proposals have been made to support various numerologies regarding time-frequency resource unit standards by considering various scenarios, service requirements, and potential system compatibility in the 3rd Generation Partnership Project (3GPP) New Radio (NR) system.

[0005] In addition, to overcome the adverse channel environment such as high path loss, phase noise and frequency offset that occurs at high carrier frequencies, the NR system can support the transmission of physical signals / channels through multiple beams. In this way, the NR system can support a variety of applications, such as enhanced mobile broadband (eMBB), massive machine type communication (mMTC) / ultra-machine type communication (uMTC), and ultra-reliable and low-latency communication (URLLC).

[0006] In addition, vehicle-to-everything (V2X) communication may be considered, i.e., a communication method for exchanging or sharing road infrastructure and information (e.g., traffic conditions) by communicating with other vehicles during driving. V2X may include, for example, vehicle-to-vehicle (V2V) (which may refer to Long Term Evolution (LTE)-based / New Radio (NR)-based communication between vehicles), vehicle-to-pedestrian (V2P) (which may refer to LTE-based / NR-based communication between a vehicle and a user equipment (UE) carried by a user), and vehicle-to-infrastructure / network (V2I / N) (which may refer to LTE-based / NR-based communication between a vehicle and a roadside unit (RSU) / network). The RSU may be a transportation infrastructure entity configured by a base station or a fixed UE, such as an entity that sends speed notifications to a vehicle. Summary of the invention Technical Topics

[0008] The present disclosure relates to rate matching methods and apparatus for New Radio (NR) Sidelink-Unlicensed (SL-U) data channel transmission and reception in unlicensed bands. The present disclosure relates to methods and apparatus for determining a transport block size (TBS) of a physical sidelink shared channel (PSSCH) within an NR SL-U system in an unlicensed band.

[0009] Technical Solution

[0010] A method of performing sidelink communication in an unlicensed band may include: determining entire resource elements (REs) for a physical sidelink shared channel (PSSCH); and determining a transport block size (TBS) based on the entire REs.

[0011] Technical Effects

[0012] The present disclosure may provide a rate matching method for New Radio (NR) Side Link-Unlicensed (SL-U) data channel transmission and reception in an unlicensed band.

[0013] The present disclosure may provide a method for determining a transport block size (TBS) of a physical sidelink shared channel (PSSCH) within an NR SL-U system in an unlicensed band. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 An example of describing a New Radio (NR) frame structure to which the present disclosure is applicable is shown.

[0016] Figure 2 The NR resource structure to which the present disclosure is applicable is shown.

[0017] Figure 3 The NR side link time slot structure to which the present disclosure is applicable is shown.

[0018] Figure 4 NR side link frequencies to which the present disclosure can be applied are shown.

[0019] Figure 5 The NR side link resource pool configuration to which the present disclosure can be applied is shown.

[0020] Figure 6 An unlicensed frequency band for each area used for NR sidelink communication to which the present disclosure is applicable is shown.

[0021] Figure 7 The use of a 5 gigahertz (GHz) unlicensed frequency band to which the present disclosure may be applied is shown.

[0022] Figure 8 A method of increasing bandwidth in consideration of power spectral density (PSD) limitations to which the present disclosure may be applied is shown.

[0023] Fig. 9 A method of configuring a guard band in consideration of a shared frequency band within a cell to which the present disclosure can be applied is shown.

[0024] Fig.10 An interleaving-based resource block (RB) resource assignment method to which the present disclosure can be applied is shown.

[0025] Fig.11 A method of performing a listen-before-talk (LBT) procedure in an unlicensed band to which the present disclosure may be applied is shown.

[0026] Fig.12 Channel Occupancy Time (COT) sharing and discovery burst transmission to which the present disclosure may be applied are shown.

[0027] Fig.13 A method of applying cyclic prefix (CP) extension to an uplink when COT sharing is performed between a downlink and an uplink, to which the present disclosure may be applied, is shown.

[0028] Fig.14 A semi-static channel access procedure to which the present disclosure can be applied is shown.

[0029] Fig.15 A method of performing channel occupation to which the present disclosure can be applied is shown.

[0030] Fig.16 A method of configuring a bandwidth part (BWP) in a sidelink unlicensed band and a resource block set (RBS) in a resource pool, to which the present disclosure can be applied, is shown.

[0031] Fig.17 A resource pool configuration method for a side link unlicensed band to which the present disclosure can be applied is shown.

[0032] Fig.18 A frequency resource-based sidelink unlicensed band resource pool configuration using interlace assignment to which the present disclosure can be applied is shown.

[0033] Fig.19 A side link unlicensed band resource pool configuration method to which the present disclosure can be applied is shown.

[0034] Fig. 20 It may be applicable to CPE and PSSCH RM operation of the sidelink unlicensed band of the present disclosure.

[0035] Fig.21PSSCH assignments and automatic gain control (AGC) / gap existence states in various sidelink unlicensed (SL-U) scheduling and channel occupancy scenarios applicable to the present disclosure are shown.

[0036] Fig. 22 A PSSCH suitable for use in the present disclosure is shown.

[0037] Fig.23 PSSCH DMRS overhead control considering multi-time transmission interval (TTI) scheduling in SL-U applicable to the present disclosure is shown.

[0038] Fig.24 A PSCCH duplication assigned to an RBS and transmitted, applicable to the present disclosure, is shown.

[0039] Fig.25 An SL-SSB suitable for use in the present disclosure is shown.

[0040] Fig.26 Devices to which the present disclosure can be applied are shown. DETAILED DESCRIPTION

[0042] Various examples of the present disclosure will be described more fully below with reference to the accompanying drawings so that those skilled in the art to which the present disclosure pertains can easily implement these examples. However, the present disclosure may be implemented in various forms and is not limited to the examples described herein.

[0043] When describing examples of the present disclosure, detailed descriptions of known configurations or functions may be omitted for clarity and conciseness. Throughout the drawings and detailed description, unless otherwise specified, the same reference numerals are understood to refer to the same elements, features, and structures.

[0044] It will be understood that when an element is referred to as being "connected to," "coupled to," or "accessed to" another element, it may be directly connected, coupled to, or accessed to the other element, or intervening elements may be present. Furthermore, it will be understood that when an element is described as "including / comprising" or "having" another element, it specifies the presence of the other element, but does not preclude the presence of the other element described in other ways.

[0045] In addition, terms such as first, second, etc. can be used to describe the elements in the description herein. These terms are used to distinguish an element from another element. Therefore, the terms do not limit the elements, arrangement order, or sequence, etc. Therefore, the first element in one example can be referred to as the second element in another example. Likewise, the second element in one example can be referred to as the first element in another example.

[0046] Here, providing distinguishing elements is only for the purpose of clearly explaining each feature, and does not mean that the elements must be separated from each other. That is, multiple elements can be integrated into a single hardware or software unit. Moreover, a single element can be distributed to multiple hardware or software units. Therefore, unless otherwise described, integrated or distributed examples are also included in the scope of this disclosure.

[0047] Here, the elements described in various examples may not necessarily be necessary and may be partially optional. Therefore, examples including a partial set of elements described in the examples are also included in the scope of this disclosure. In addition, examples including another element other than the elements described in various examples are also included in the scope of this disclosure.

[0048] The description described herein relates to a wireless communication network, and operations performed in the wireless communication network may be performed in a process in which a system (eg, base station) controlling the wireless network controls the network and transmits data, or may be performed in a user equipment.

[0049] Obviously, in a network including a base station and a plurality of network nodes, various operations performed for communicating with a UE may be performed by the base station or other network nodes other than the base station. Here, the term "base station (BS)" may be used interchangeably with other terms, such as a fixed station, a Node B, an eNodeB (eNB), a gNodeB (gNB), and an access point (AP). In addition, the term "terminal" may be used interchangeably with other terms, such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), a subscriber station (SS), and a non-AP station (non-AP STA).

[0050] Here, sending or receiving a channel includes the meaning of sending or receiving information or signals through the corresponding channel. For example, sending a control channel means sending control information or signals through the control channel. Similarly, sending a data channel means sending data information or signals through the data channel.

[0051] In the following description, although the term “New Radio (NR) system” is used to distinguish a system according to various examples of the present disclosure from an existing system, the scope of the present disclosure is not limited thereto.

[0052] The New Radio (NR) system supports various subcarrier spacings (SCS) by considering various scenarios, service requirements, potential system compatibility, etc. In addition, in order to overcome the adverse channel environment such as high path loss, phase noise, and frequency offset that occur at high carrier frequencies, the NR system can support the transmission of physical signals / channels through multiple beams. In this way, the NR system can support a variety of applications, such as enhanced mobile broadband (eMBB), massive machine type communication (mMTC) / ultra machine type communication (uMTC), and ultra-reliable and low-latency communication (URLLC).

[0053] Here, 5G mobile communication technology can be defined by including the existing advanced long term evolution (LTE-A) system and the above-mentioned NR system. That is, 5G mobile communication technology can be operated by considering backward compatibility with previous systems and newly defined NR systems. Therefore, subsequent 5G mobile communication may include technologies based on NR system operation and technologies based on previous systems (e.g., LTE-A, LTE), but is not limited to a specific system.

[0054] First, the physical resource structure of the NR system to which the present disclosure is applied will be briefly described.

[0055] Figure 1 An example of an NR frame structure according to an example of the present invention is shown.

[0056] In NR, the basic unit of time domain can be T c =1 / (Δf max ·N f ). Here, Δf max =480·10 3 And N f =4096. In addition, κ = T s / T c =64 may be a constant related to the multiple relationship between the NR time unit and the LTE time unit. In LTE, T s =1 / (Δf ref ·N f，ref ), Δf ref =15·10 3 And N f，ref = 2048 can be defined as a reference time unit. The constant of the multiple relationship between the NR time basic unit and the LTE time basic unit can be defined as k = T s / T c =64.

[0057] Reference Figure 1 , which may include a time structure of a frame for downlink / uplink (DL / UL) transmission, which may include T f =(Δfmax N f / 100)·T s = 10 ms. Here, a single frame may include a time period corresponding to T sf =(Δf max N f / 1000)·T s = 10 subframes of 1 ms. The number of consecutive OFDM symbols per subframe can be In addition, each frame may be divided into two half frames, and the half frame may include subframes 0 to 4 and subframes 5 to 9. Here, half frame 1 may include subframes 0 to 4, and half frame 2 may include subframes 5 to 9.

[0058] N TA Denotes the timing advance (TA) between downlink (DL) and uplink (UL). Here, according to the following equation 1, the transmission timing of the uplink transmission frame i is determined based on the downlink reception timing at the UE.

[0059] [Equation 1]

[0060] T TA =(N TA +N TA,offset )T c

[0061] N TA,offset Indicates the TA offset value due to duplex mode differences, etc. Basically, in frequency division duplex (FDD), N TA，offset = 0. In time division duplex (TDD), N can be defined by considering the margin of DL-UL switching time. TA，offset For example, in TDD (Time Division Duplex) of RF1 (Frequency Range 1) (which is a frequency below 6 GHz or lower), N TA,offse t can be 39936T C or 2600T C .39936T C =20.327μs and 25600T C =13.030μs. In addition, in FR2 (frequency range 2) of millimeter wave (mmWave), N TA,offset It can be 13792T C At this time, 39936T C =7.020μs.

[0062] Figure 2 An NR resource structure to which the present disclosure is applicable is shown.

[0063] Resource elements within a resource grid may be indexed based on each subcarrier spacing. Here, a single resource grid may be generated for each antenna port and each subcarrier spacing. Uplink / downlink transmission and reception may be performed based on the corresponding resource grid.

[0064] A resource block (RB) in the frequency domain is configured with 12 REs, and for every 12 REs, an RB index (n PRB ). The index of the RB may be used within a specific frequency band or system bandwidth. The index of the RB may be defined as shown in the following equation 2. Here, N RB sc represents the number of subcarriers in each RB, and k represents the subcarrier index.

[0065] [Equation 2]

[0066]

[0068] The digital parameter configuration can be configured differently to meet various services and requirements of the NR system. For example, one subcarrier spacing (SCS) can be supported in the LTE / LTE-A system, but multiple SCSs can also be supported in the NR system.

[0069] The new digital parameter configuration of the NR system supporting multiple SCSs can operate in a frequency range or carrier such as 3 GHz or less, 3 GHz-6 GHz, 6 GHz-52.6 GHz or more to solve the problem that a wide bandwidth cannot be obtained in a frequency range or carrier such as 700 MHz or 2 GHz.

[0070] Table 1 below shows an example of digital parameters supported by the NR system.

[0071] [Table 1]

[0072] μ <![CDATA[Δf=2 μ ·15[kHz]]]> Cyclic prefix 0 15 Normal 1 30 Normal 2 60 Normal, extended 3 120 Normal 4 240 Normal

[0073] Referring to Table 1 above, the digital parameter configuration may be defined based on the SCS used in the OFDM system, the cyclic prefix (CP) length, and the number of OFDM symbols per time slot. The above values ​​may be provided to the UE through higher layer parameters DL-BWP-mu and DL-BWP-cp for the downlink, and through higher layer parameters UL-BWP-mu and UL-BWP-cp for the uplink.

[0074] In the above Table 1, if μ=2 and SCS=60 kHz, normal CP and extended CP may be applied. In other frequency bands, only normal CP may be applied.

[0075] Here, a normal slot may be defined as a basic time unit for sending a single piece of data and control information in an NR system. The length of a normal slot may basically include 14 OFDM symbols. In addition, unlike a slot, a subframe may have an absolute time length corresponding to 1ms in an NR system and may be used as a reference time for the length of another time segment. Here, for the coexistence and backward compatibility of LTE and NR systems, the NR standard may require a time segment such as an LTE subframe.

[0076] For example, in LTE, data may be transmitted based on a transmission time interval (TTI) as a unit time. TTI may include at least one subframe unit. Here, even in LTE, a single subframe may be set to 1 ms and may include 14 OFDM symbols (or 12 OFDM symbols).

[0077] In addition, in the NR system, non-slots can be defined. Non-slots may refer to slots having at least one less symbol than the number of symbols of ordinary slots. For example, in the case of providing low latency such as ultra-reliable and low-latency communication (URLLC) services, latency can be reduced by non-slots having a smaller number of slots than the number of slots of ordinary slots. Here, the number of OFDM symbols included in the non-slots can be determined based on the frequency range. For example, non-slots having a length of 1 OFDM symbol in a frequency range of 6 GHz or higher can be considered. As another example, the number of symbols used to define a non-slot may include at least two OFDM symbols. Here, the number range of OFDM symbols included in the non-slots can be configured to have a micro-slot length of up to (ordinary slot length) -1. Here, although the number of OFDM symbols can be limited to 2, 4 or 7 as a non-slot standard, it is provided only as an example.

[0078] In addition, for example, SCS corresponding to μ = 1 and 2 can be used in unlicensed bands of 6 GHz or less, and SCS corresponding to μ = 3 and 4 can be used in unlicensed bands above 6 GHz. Here, for example, if μ = 4, it can be used for synchronization signal blocks (SSBs).

[0079] [Table 2]

[0080]

[0081] Table 2 shows the number of OFDM symbols per time slot for a normal CP set by subcarrier spacing. The number of time slots per frame and the number of time slots per subframe In Table 2, the values ​​are based on a normal slot with 14 OFDM symbols.

[0082] [Table 3]

[0083]

[0084] In Table 3, in the case where extended CP is applied (ie, μ=2 and SCS=60 kHz), the number of slots per frame and the number of slots per subframe based on normal slots where the number of OFDM symbols per slot is 12 are shown.

[0085] As described above, a single subframe may correspond to 1 ms on the time axis. Moreover, a single time slot may correspond to 14 symbols on the time axis. For example, a single time slot may correspond to 7 symbols on the time axis. Therefore, the number of time slots and the number of symbols that may be considered may be set differently within 10 ms corresponding to a single radio frame. Table 4 may show the number of time slots and the number of symbols according to each SCS. Although an SCS of 480 kHz may not be considered in Table 4, the present disclosure is not limited to such an example.

[0086] [Table 4]

[0087]

[0089] The V2X service may support a set of basic requirements for V2X services. These requirements are basically designed with full consideration of road safety services. Here, the V2X UE may exchange autonomous state information via the SL. The V2X UE may also exchange information with infrastructure nodes and / or pedestrians.

[0090] The V2X service (e.g., LTE Rel-15) may support at least one of: carrier aggregation in SL, high order modulation, latency reduction, transmit (Tx) diversity, and sTTI (transmission time interval). To this end, new features may be applied to V2X communication. More specifically, a V2X UE may operate in consideration of coexistence with other V2X UEs. For example, a V2X UE may use the same resource pool as other V2X UEs.

[0091] For example, by considering the use case for supporting V2X services as system aspect (SA) 1, the technical features can be classified mainly based on the four categories represented by Table 5 below, but not limited thereto. In Table 5, "vehicle platooning" may be a technology that enables multiple vehicles to dynamically form a group and operate similarly. "Extended sensor" may be a technology that enables the exchange of data collected from sensors or video images. "Advanced driving" may be a technology that enables a vehicle to drive based on semi-automation or fully automation. "Remote driving" may be a technology for remotely controlling a vehicle and a technology for providing an application. Based on this, further description related thereto is given through Table 5 below.

[0092] [Table 5]

[0093]

[0094] In addition, SA1 can support the case of operating in various systems (such as LTE and NR) because enhanced V2X (eV2X) supports technology for supporting the V2X service. For example, the NR V2X system can be the first V2X system. In addition, the LTE V2X system can be the second V2X system. That is, the NR V2X system and the LTE V2X system can be different V2X systems.

[0095] The following describes a method for satisfying the low latency and high reliability required in the NR SL based on the NR V2X system. However, the same or similar composition can be extended and applied to the LTE V2X system, and includes but is not limited to the following examples. That is, in the LTE V2X system, the present disclosure can be applied to the interactive part.

[0096] Here, the NR V2X capability may not be limited to basically supporting only V2X services, and the V2X RAT to be used may be selected.

[0097] In addition, new service requirements for public safety and commercial use cases of NR V2X services may be further considered. For example, the use cases may include, but are not limited to, at least one of the following: more advanced V2X services, public safety services, network control interactive services (NCIS), railway gap analysis (MONASTERYEND), enhanced relay for energy efficient and extensive coverage (REFEC), and audio-visual service production (AVPROD) certification.

[0098] Physical channels, signals, basic time slot structures and physical resources may be configured for NR V2X. Here, the NR physical SL shared channel (NR PSSCH) may be a physical layer NR SL data channel. V2X UEs may exchange data and control information (e.g., 2nd SCI, CSI) through the NR PSSCH. The NR physical SL control channel (NR PSCCH) may be a physical layer NR SL control channel. NRPSCCH refers to a channel for sending scheduling information of the NR SL data channel and control information (1st SL control information (SCI)) including the 2nd SCI indication. That is, the V2X UE may send control information for SL data communication to another V2X UE through the PSCCH. The NR physical SL feedback channel (NR PSFCH) refers to a channel for sending physical layer NR hybrid automatic repeat request (HARQ) feedback information and a channel for sending HARQ-ACK feedback information corresponding to the NR SL data channel (i.e., PSSCH). A V2X UE may send data to another V2X UE and may then receive HARQ feedback information of the corresponding data through the NR PSFCH. NRSL synchronization signal / physical SL broadcast channel (SLSS / PSBCH) block refers to a channel block that sends NR SL synchronization signal and broadcast channel in a single continuous time. Here, SLSS / PSBCH blocks can be periodically sent based on a set of one or more block indexes to support beam-based transmission in the NR band. The synchronization signal includes a primary SL synchronization signal (PSSS) and a secondary SL synchronization signal (SSSS). The synchronization signal is generated based on at least one SLSSID value. NR physical SL broadcast channel (PSBCH) refers to a channel used to send system information required to perform V2X SL communication. NR PSBCH is sent together with SLSS and is periodically sent based on a set of SLS / PSBCH block indices to support beam-based transmission.

[0099] In addition, PSCCH and PSSCH may be defined to support NR V2X. A UE may send SCI to another UE via PSCCH. Here, a Tx UE may send a first SCI (1st SCI, SCI format 1-A) to an Rx UE via PSCCH. The 1st SCI may be used to schedule PSSCH and auxiliary SCI (2nd SCI) within the PSSCH, and the 1st SCI may include priority information, time / frequency resource allocation information, resource reservation information, demodulation reference signal (DMRS) mode information, 2nd SCI format indicator information, 2nd beta-offset indicator information as a parameter for SCI and PSSCH rate matching operation, DMRS port count information, modulation and coding scheme (MCS) information, additional MCS table indicator information (e.g., indicating 64QAM, or 256OAM or one of the URMCSLLC tables), PSFCH overhead indicator information (a parameter for PSSCH rate matching operation with the 2nd SCI), and at least one reserved bit.

[0100] Figure 3 The NR SL time slot structure to which the present disclosure can be applied is shown.

[0101] refer to Figure 3 , a single SL slot (SL slot) includes a single automatic gain control (AGC) symbol. Moreover, a single SL slot includes a single Tx-Rx switching symbol. In a single SL slot, the PSSCH is a channel through which data is transmitted, which is transmitted through at least one subchannel (e.g., Figure 3 In addition, in the time domain, the PSCCH (1st SCI), the 2nd SCI, the PSSCH (data), and the demodulation RS (DMRS) for demodulation may be transmitted to the remaining OFDM symbols except the AGC symbol and the Tx-Rx switching symbol. In detail, the positions of the PSCCH (1st SCI), the 2nd SCI, the PSSCH (data), and the DMRS for demodulation may be the same as Figure 3 The same as in, but not limited to this. For example, in Figure 3 In the example, the PSCCH and the second SCI exist in the first subchannel, and considering this, the PSSCH and the DMRS can be allocated. As another example, the second subchannel refers to a subchannel in which the PSCCH and the second SCI do not exist, and the PSSCH and the DMRS can be allocated as follows: Figure 3 is allocated as in.

[0102] Here, the number of PSSCH DMRS can be configured according to the higher layer configuration, and one or more PSSCH DMRS can be configured according to the channel environment of the UE. PSCCH (1st SCI) uses the DMRS of PSCCH (ie, PSCCH DMRS) for reception and demodulation, and every four resource elements (REs) are equally allocated and transmitted within a single resource block (RB). In contrast, PSSCH DMRS is used to decode the 2nd SCI.

[0103] In addition, for example, a single resource pool associated with NR SL can support frequency division multiplexing (FDM), time division multiplexing (TDM), and space division multiplexing (SDM). This means that each resource in a single resource pool can be divided and used based on frequency, time, and space, which can improve resource efficiency.

[0104] Figure 4 NR SL frequencies to which the present disclosure can be applied are shown. For example, NR SL can operate based on at least one of the following: frequency range 1 (FR1) (below 6 GHz) and frequency range 2 (FR2) (i.e., up to 52.6 GHz), unlicensed ITS bands, and licensed bands. In detail, for example, refer to Figure 4 , 5,855 to 5,925 MHz can be allocated for ITS services (technology neutral manner).

[0105] In addition, NR V2X quality of service (QoS) requirements may be considered. That is, latency, reliability, and data rate may need to be met by predetermined conditions related to the requirements of the NR V2X service. Here, these requirements may be configured as shown in Table 6 below, and Table 7 may show PC5 QoS for NR V2X.

[0106] Here, in order to meet the QoS requirements, access stratum (AS) level QoS management may be required. To this end, HARQ and CSI feedback associated with link adaptation may be required. In addition, each of the NR V2X UEs may have a different maximum bandwidth capability (maximum BW capability). Taking this into account, AS-level information may be exchanged between NR V2X UEs, the AS-level information including at least one of the following: UE capabilities, QoS related information, radio bearer configuration, and physical layer configuration.

[0107] [Table 6]

[0108]

[0109] [Table 7]

[0110] NOTE 1: For standardized PQI to QoS characteristics mapping, this table may be extended / updated to support service requirements of other identified V2X services. Note 2: PQI can be used for services other than V2X.

[0112] In the following, the SL HARQ process is described. Whether the V2X UE is to report HARQ feedback is indicated by a higher layer (e.g., RRC) configuration and SCI signaling (e.g., 2nd SCI). For example, if the V2X UE performs SL communication based on multicast, it can be determined whether to report HARQ feedback based on the distance between the Tx UE and the Rx UE.

[0113] When the V2X UE performs at least one of unicast and multicast transmission, SL HARQ feedback may be enabled or disabled. Here, enabling / disabling HARQ feedback may be determined based on at least one of channel conditions (e.g., RSRP), the distance between the Tx UE and the Rx UE, and QoS requirements.

[0114] In the case of multicast, whether to send HARQ feedback can be determined based on the physical distance between the Tx UE and the Rx UE. Here, when HARQ feedback is performed for multicast transmission via PSSCH, the Rx UE can send a negative response only when the received PSSCH decoding fails. It can be referred to as Option 1 operation. In addition, when HARQ feedback is performed for multicast transmission via PSSCH, the Rx UE can feedback a positive response or a negative response based on whether the PSSCH decoding is successful, and this can be referred to as Option 2 operation. In Option 1 operation where only a negative response is fed back as only NACK HARQ feedback, if the physical distance between the Tx UE and the Rx UE is less than or equal to the communication range requirement, HARQ feedback corresponding to PSSCH reception can be performed. On the contrary, if the physical distance between the Tx UE and the Rx UE is greater than the communication range requirement, the V2X UE may not perform HARQ feedback corresponding to PSSCH reception.

[0115] Here, the location of the Tx UE is indicated to the Rx UE through SCI signaling associated with the PSSCH. The Rx UE may estimate the distance from the Tx UE based on both the information fragment included in the received SCI and its location information, and may operate as described above.

[0116] In addition, when unicast communication is performed based on V2X, the case where SL HARQ feedback is enabled can be considered. The Rx UE can generate and send HARQ ACK / NACK corresponding to the PSSCH according to whether the decoding of the corresponding transport block (TB) is successful.

[0117] Then, the NR SL resource allocation mode refers to a mode in which the base station schedules SL transmission resources. Here, the mode in which the base station schedules SL transmission resources may be mode 1. For example, when the V2X UE is within the coverage of the base station, the V2X UE may receive SL resource information from the base station. On the contrary, there is a mode in which the V2X UE directly determines the resources for SL transmission on the SL resources configured by the base station / network or the pre-configured SL resources. Here, the mode in which the UE directly determines the SL transmission resources may be mode 2.

[0118] In addition, a digital parameter configuration and waveform for the side link may be considered, which may be as shown in Table 8 below. In detail, regarding PSSCH / PSCCH and PSFCH in the side link, the SCS and CP length supported in each of FR1 and FR2 may be as shown in Table 8 below. Here, the waveform may support only OFDM without supporting DFT-S-OFDM, but may not be limited thereto. A side link synchronization signal block (SL-SSB) may be independently defined for each frequency range, which may be similar to NR-Uu.

[0119] [Table 8]

[0120]

[0122] Figure 5 The NR side link (SL) resource pool configuration is shown. Figure 5 , the resource pool may represent resources in time and frequency for sidelink transmission and reception. For example, at least one resource pool may be configured within a single SLBWP within a single carrier. Here, the resources of the resource pool may be configured based on the time resources of a time slot set unit and the frequency resources of a continuous subchannel set unit. In addition, the resource pool may be configured for each of transmission and reception.

[0123] In more detail, as a time resource for resource pool configuration provided in the NR side link, at least one of the following may be configured: a resource pool period (period), a side link time slot set (sl-TimeResource (length = L) within a single resource pool application period, bitmap)), and the first symbol and the number of consecutive symbols in a set of consecutive symbols within a single time slot. As frequency resources, at least one of the following can be configured: the bandwidth of at least one subchannel (for example, sl-SubchannelSize = {10, 15, 20, 25, 50, 75 and 100} RB), the entire bandwidth of the resource pool indicated by the number of consecutive subchannels (a set of consecutive subchannels (for example, sl-NumSubchannel = {1 to 27})), and the position of the first subchannel of the resource pool in the frequency domain (sl-StartRBsubChannel = {0 to 265}). For example, resources in the time domain and frequency domain can be configured based on higher layer parameters. In Figure 5 In the case where the total available RB resources do not completely match the subchannel size (i.e., if it does not reach the number of RBs constituting a single subchannel), the frequency resources corresponding to the excluded resource blocks (RBs) may indicate some remaining RBs. Here, the corresponding resources may not be used in the NR side link. In addition, for example, in the case where multiple units of the length of the bitmap on the time resource (e.g., sl-TimeResource) are not established and cannot be used as NR side link resources, the reserved time slots may indicate the remaining time slots.

[0124] Next, a case where an unlicensed band (unlicensed spectrum) is used for communication between a base station and a UE may be considered. For example, a communication scheme based on an unlicensed band may be a scheme in which communication is performed by competing for an occupied channel and based on the occupied channel. Even for communication between a base station and a UE, communication based on an unlicensed band may be performed. Below, operations based on a case in which an unlicensed band is used for sidelink communication are described. That is, even for sidelink communication as communication between UEs, an unlicensed band may be used. In addition, it is necessary to consider configuring a sidelink resource pool using a sidelink unlicensed band. In more detail, sidelink communication may be performed based on a resource pool. In the case of performing communication via an unlicensed band, the resource pool configuration needs to be configured differently.

[0125] For example, a resource pool for side link communication may be configured based on a time slot unit, and symbols that can be used for the side link within a time slot may be determined, which is similar to Figure 5 In addition, as mentioned above, Figure 5 As described, in the frequency domain, it can be configured based on the number of consecutive subchannels. The above sidelink resource pool configuration can be configured in consideration of unlicensed band communications, which will be described below.

[0126] Figure 6The unlicensed frequency band of each area of ​​NR side link communication to which the present disclosure is applicable is shown. In the above Table 8, the frequency range of NR FR1 may be from 450 MHz to 6 GHz, but the corresponding frequency range may vary from 450 MHz to 7.125 GHz. The frequency range of NR FR1 may be changed for the unlicensed frequency band of the 6 GHz band, but may not be limited thereto.

[0127] For example, the unlicensed frequency band may be located below 1 GHz, 2.4 GHz, 5 GHz, 6 GHz, 37 GHz (US only), and 60 GHz, but may not be limited thereto. Figure 6 For example, in the system, the 5 GHz band may be Band 46 defined as 5150 to 5925 MHz. In addition, for example, for LAA operation, Band 49 (3550-3700 MHz) may be defined as Citizens Broadband Radio Service (CBRS), but is not limited thereto.

[0128] Figure 7 The use of the 5 GHz unlicensed frequency band to which the present disclosure can be applied is shown. Figure 7 , each frequency band within the 5GHz unlicensed frequency band can be set, and based on this, the use of the unlicensed frequency band can be set. For example, it can be divided into 20MHz units, and each 20MHz can be a single channel.

[0129] Here, the low frequency band of 5150 to 5350 MHz within the above frequency band is specified in most areas to have a maximum transmission power of 23 dBm for indoor use. Also, in the frequency band of 5470 MHz or higher, it is used in areas with a transmission power of up to 30 dBm, and is used for outdoor use in most areas. Here, for example, there may be additional requirements in some areas, which are given as effective isotropic radiated power (EIRP) values ​​based on the following Table 9, and the maximum transmission power is limited.

[0130] [Table 9]

[0131]

[0133] Here, the power spectral density (PSD) may indicate that the device is limited to performing full power transmission within the reference bandwidth. As a detailed example, European regulations may limit the PSD to 10dBm / MHz. Therefore, in a non-20MHz bandwidth, the device may not perform transmission at the maximum transmit power of 23dBm.

[0134] Figure 8 The present disclosure is applicable to increase the bandwidth by taking into account the PSD limitation. Figure 8As shown, a small data transmission situation that only requires a small bandwidth can be considered. Here, in the case of performing small data transmission through a wide bandwidth, the coverage can be extended. In addition, the minimum bandwidth occupancy control can be satisfied by transmission with the help of a wide bandwidth. In view of this, for small data, a method of performing transmission in a wide bandwidth may be preferred.

[0135] In addition, for example, in the case of occupying a channel through a channel access process in an unlicensed band, a maximum channel occupancy time (COT) corresponding to the maximum allowable occupation time may be set differently for each region. For example, Japan allows a maximum COT of up to 4 ms, while Europe allows a maximum COT of up to 8 ms or 10 ms. However, this is merely an example and is not limited to the above embodiments. In addition, for example, Europe may support framework base equipment (FBE) and load base equipment (LBE) rules. Here, FBE may be set to high performance radio (LAN HiperLAN) / 2, and LBE may be adopted and applied according to Wi-Fi standard specifications, and both may be supported in NR as a new communication system.

[0136] In addition, for example, the minimum occupied bandwidth may be a bandwidth control that requires minimum occupancy when channel access is successful once. For example, the minimum occupied bandwidth control may be configured to occupy 80% to 90% or more of the nominal channel BW. As a detailed example, when the UE transmits a PUSCH to the base station in an unlicensed band, it may request that resources for the PUSCH be allocated in an interleaved form in a specific bandwidth, but may not be limited to the corresponding embodiments.

[0137] In addition, regulation on dynamic frequency selection may be regulation that limits bandwidth usage for the purpose of protecting a system (e.g., radio) with a high priority for using an unlicensed band. In addition, transmit power control regulation may be regulation that limits transmit power to a value much lower than the maximum transmit power value allowed for use. In addition, listen-before-talk (LBT) regulation may be regulation on a channel access procedure, and Europe may support FBE and LBE rules. Here, FBE may be Hiperlan / 2, and LBE may be adopted and applied from Wi-Fi standard specifications, and both may be supported in NR.

[0138] In addition, for example, the 5 GHz unlicensed band can be used based on the above description, but the use of the 6 GHz band is being discussed in each country and organization. Here, the 6 GHz band may be a band that is different from 5 GHz and is not used in a mobile system. That is, unlike the 5 GHz band shared by multiple mobile communication systems, the 6 GHz band can be used for a single designated communication system. Therefore, problems or inefficiencies caused by the coexistence of different systems can be reduced.

[0139] Fig. 9 A method of configuring a guard band in consideration of a shared frequency band (eg, an unlicensed frequency band) within a cell, to which the present disclosure may be applied, is shown.

[0140] Reference Fig. 9 To support broadband operation in shared spectrum access, the UE may receive the IntraCellGuardBandsPerSCS parameter for each of the UL carrier and the DL carrier from the base station based on the base station configuration. N subcarriers may be provided to the UE in a single carrier (subcarrier spacing index = μ). RB-set,x -1 cell protection band. Fig. 9 , the UE may receive higher layer signaling for the number of common resource blocks (CRBs) for each guard band and the starting CRB. For example, a CRB may be a resource block defined / configured based on point A, which is the starting position of the transmission bandwidth in the carrier in the frequency domain. The UE may verify the information about point A through base station signaling, and based on this, may identify the CRB position in the frequency domain. Here, each guard band may be based on The parameter is defined as the starting CRB, and in each guard band, the number of CRBs can be based on The UE may receive the aforementioned information through higher layer signaling based on each of the startCRB and nrofCRB parameters. Here, s∈{0,1,…,N RB-set,x -2}, N RB-set,x N represents the number of RB sets, and x can be configured as DL or UL for downlink and uplink. RB-set,x The RB sets may be configured as a resource block set (RBS) within a single carrier through a guard band configuration. For example, the guard band may be configured based on an IntraCellGuardBandsPerSCS parameter, and the RBS may be configured within a single carrier accordingly.

[0141] Here, each RBS frequency bandwidth may correspond to an LBT frequency bandwidth. That is, each RBS may be set to a bandwidth corresponding to the LBT process performed by the base station and the UE. Fig. 9In the example, if LBT is successful in the corresponding area corresponding to the LBT bandwidth, RB set 1 911 and RB set 2 912 may occupy the corresponding frequency band and may perform communication. That is, the RBS may correspond to the LBT bandwidth. For example, a Tx node (e.g., a gNB or a UE) may determine the channel occupancy of the unlicensed band by performing an LBT channel access procedure on an RBS resource corresponding to the LTE bandwidth. When the LBT procedure is successful in a single RBS, the Tx node may perform transmission on the resources corresponding to the RBS.

[0142] Here, each RBS can be defined as a start CRB and an end CRB. The start CRB can be End CRB can be Here, the size of the guard band 913 may be nrofCRB. For example, according to the subcarrier spacing μ and the carrier size It may not be desirable to set the size nrofCRB of guard band 913 to a size smaller than the number of applicable intra-cell guard bands defined in consideration of requirements regarding interference status of a wireless bandwidth.

[0143] Here, the start CRB and the end CRB of each RBS (911, 912) may be determined based on the RBS index, and the RBS index may be s∈{0,1,...,N RB-set,x -1}. That is, the RBS index s can be resource blocks of size, and represents the number of CRBs determined by the start CRB and the end CRB based on the following Equation 3. Also, in each RBS, the start CRB and the end CRB may be as shown in the following Equations 4 and 5.

[0144] [Equation 3]

[0145]

[0146] [Equation 4]

[0147]

[0148] [Equation 5]

[0149]

[0151] For example, if the UE is not provided with the IntraCellGuardBandsPerSCS parameter configuration, the UE can determine the carrier μ and carrier size based on the requirements of the RF standard. In addition, for example, if the above nominal intra-cell guard band and RBS pattern do not include an intra-cell guard band, it can be assumed that the RBS of the corresponding carrier is 1.

[0152] For example, in Fig. 9 In the embodiment, two LBT BWs (RBS 0, RBS 1) can be configured in a single BWP 922 within a single carrier bandwidth. Here, a single guard band 913 can be configured between the two RBSs 911 and 913. The location of each of the two RBSs 911 and 913 can be as follows: Fig. 9 As shown, it is determined based on the above-mentioned higher layer parameters. In addition, for example, when multiple BWPs 921 and 923 are configured within a single carrier bandwidth, the RBS associated with each BWP can be verified. Here, the RBSs corresponding to the first RBS (= s0, 912) and the last RBS (= s1, 911) of each BWP in the RBSs 911 and 912 within the carrier can be indexed by s0 and s1 indexes.

[0153] Fig.10 An interleaving-based RB resource assignment method applied to the present disclosure is shown. PUCCH / PUSCH transmission can be performed by RB resources allocated based on interleaving. Here, the reference point of the RB resources allocated based on interleaving can be point A1010. The UE can obtain information about point A 1010 through base station signaling, as described above. In addition, a common resource block (CRB) can be a resource block defined / configured based on point A 1010 as a starting position point of the transmission bandwidth on the carrier. That is, when physical uplink control channel (PUCCH) / physical uplink shared channel (PUSCH) transmission is performed using interleaving-based RB resources, all interleavings can be used based on the same configuration on the carrier based on reference point A 1010 and CRB. For example, as described above, an existing wireless communication system (e.g., LTE LAA) and a wireless communication system (e.g., NR) can perform PUCCH / PUSCH transmission using interleaving-based RB resources, but may not be limited thereto.

[0154] For example, in the case of a 15kHz SCS, an interleave of M=10 may be defined for the entire bandwidth. In the case of a 30kHz SCS, an interleave of M=5 may be defined for the entire bandwidth. In addition, X bits may be provided for interleave assignments via signaling associated with frequency resource assignments. As a detailed example, if X=5 for a 30kHz SCS, then X bits may indicate all possible interleave combinations. As another example, if X=6 for a 15kHz SCS, then X bits may indicate a starting interleave index and a number of consecutive interleaves. For example, based on a combination of a starting interleave index and a number of consecutive interleaves, a value of 55 may be required. Therefore, when indicated with 6 bits, there may be 9 remaining RIV values, and the 9 remaining RIV values ​​may indicate a specific predefined interleave combination.

[0155] In addition, through the signaling related to the frequency resource assignment, Y bits can be provided for the RB set assignment. The RB set assignment can be a start and end RB set based on the RIV format. Here, the RB set can be continuous at all times. In addition, for example, when two adjacent RB sets are assigned, a guard band between the RB sets can also be assigned, and the guard band can be used as a frequency resource.

[0156] In addition, for example, a method may be required to fairly access and use channels between various wireless access technologies / systems (e.g., Wi-Fi, LAA, NR-U, etc.) in unlicensed bands. For example, channel access rules (e.g., ETSI rules) based on the above-mentioned 5 GHz and 6 GHz bands may be provided, and matters as shown in Table 10 below may be specified, but may not be limited thereto.

[0157] [Table 10]

[0158]

[0159] Here, as a channel access method based on Table 10, frame-based equipment (FBE) and load-based equipment (LBE) rules may be supported. For example, the LBE access rule may consider the factors of Table 11 below. Channel access may be performed by determining the channel occupancy state based on a clear channel assessment (CCA) measurement. In addition, transmission based on an occupied channel may be performed after determining a transmit power based on channel occupancy.

[0160] [Table 11]

[0161]

[0163] Channel access priority classes (CAPCs) may be set for channel access, which may be shown in Table 12. Here, priority classes may specify priorities based on specific traffic types and quality of service (QoS) requirements. For example, in Table 12, four priority classes may be defined. Here, different priority counter (p) values ​​may be specified for each priority. Here, the higher the priority class, the lower the priority counter value may be.

[0164] In addition, for example, the channel occupancy time (COT) can be the transmission burst duration. Here, the maximum COT limit can be determined differently for each different priority class. A higher priority class can have a shorter maximum COT duration. That is, a higher priority class can have a lower priority counter value and a shorter maximum COT duration.

[0165] In addition, for example, the contention window (CW) may be a window for selecting a counter value to perform a backoff procedure for channel access. Here, the contention window may be different for each priority class, which may be shown in Table 12 below.

[0166] [Table 12]

[0167]

[0169] Fig.11 A method for performing a listen-before-talk (LBT) process in an unlicensed band to which the present disclosure can be applied is shown. For example, based on the aforementioned LBE, a type 1 LBT process (LBT category 4) can be considered. The LBT process can be set based on category 1 to category 4, which will be described below. Fig.11 , the Tx node may wait to verify whether the channel is available for a defer period (defer period) (S1110). Here, the defer period may be determined based on the priority category of Table 13 below. For example, the defer period may measure whether the channel is available for at least 25us. Here, it may be considered to send feedback information about data transmission within a maximum of 16us. In view of the above, the defer period may measure whether the channel is available for at least 25us.

[0170] When it is determined that the channel is available during the postponement period, the corresponding node may perform a backoff process. Here, the backoff counter N may be initialized to a random value between 0 and the CW value (S1120). That is, a random value between 0 and the CW value may be used as a backoff counter. Here, whether the channel is available may be counted based on a 9us time slot, and as many backoffs as the backoff counter value may be performed. Here, a larger backoff value may be set based on a larger contention window, and the probability of conflict may be reduced accordingly.

[0171] Then, it can be determined whether the backoff counter value is 0 (S1130). If the backoff counter value is 0, the corresponding node can perform the transmission. The corresponding node can use the channel based on the priority of the transmission until the maximum COT allowed to be occupied. On the contrary, if the backoff counter value is not 0, the backoff counter value can be decremented, that is, reduced (S1140). Then, it can be determined whether the channel is idle in the next 9us time slot (S1150). Here, if the channel is idle in the 9us time slot, it can be verified again whether the backoff counter value is 0. If the backoff counter value is not 0, the operation of reducing the backoff counter value can be repeated. Thus, if the backoff counter value becomes 0, the above-mentioned transmission can be performed.

[0172] On the contrary, if the channel is not idle in the 9us time slot, the corresponding node can wait again for the amount of time corresponding to the postponement period, and then verify whether the channel is available based on the backoff counter value (S1160). Based on the above, the corresponding node can occupy the unlicensed band and can perform transmission. In addition, for example, the postponement period of the downlink / uplink based on the priority class, the possible contention value and the maximum COT can be as shown in Table 13 below.

[0173] [Table 13]

[0174]

[0176] Here, for example, the contention window size can be adjusted based on HARQ feedback. In detail, if the HARQ feedback received for the first transmission performed by the corresponding node within the COT is NACK, the contention window size can be doubled in consideration of retransmission. On the contrary, if the HARQ feedback received for each transmission is ACK, the contention window size can be reset to the CW minimum value. Here, adjusting the contention window size by the first transmission within the COT may result in a conflict in the first transmission after the node occupies the channel. In the above case, it is necessary to update the contention window size. On the other hand, based on a poor channel environment or other reasons for non-conflict occurrence, it is likely that a NACK will be received for a transmission after the first transmission within the COT. Therefore, as described above, the contention window size can be adjusted based on feedback from the first transmission within the COT.

[0177] As another example, contention window adjustment for downlink (DL) / uplink (UL) transmission based on the configured grant may be performed based on feedback information in the downlink / feedback information in the uplink, respectively. In addition, for example, when there is no downlink feedback transmission in the uplink transmission based on the uplink grant, contention window adjustment may be performed by a new data indicator (NDI), but is not limited to a specific embodiment.

[0178] In addition, for example, an energy detection (ED) threshold (TL) can be determined based on parameters, channel bandwidth, and other values. As another example, the ED threshold may be determined based on whether the carrier frequency is shared with other wireless access technologies (e.g., WiFi) or whether the installation method ensures that only a specific wireless communication system (e.g., NR) is used. As a detailed example, in a 5GHz band coexisting with other systems, for a 20MHz carrier, the maximum threshold may be set to -72dBm. Here, -72dBm may be a value determined by comparison with other wireless communication systems (e.g., WiFi systems), but may not be limited to a specific embodiment. As another example, if only a specific wireless communication system (e.g., NR) uses the carrier frequency, then, for a 20MHz carrier, the maximum threshold may be used as -62dBm, and the threshold for uplink transmission may be set by RRC signaling, but may not be limited to a specific embodiment.

[0179] Then, Fig.12 COT sharing and discovery burst transmission applied to the present disclosure are shown. Fig.12 , in the case of an occupied channel, the above-mentioned type 1 LBT process, transmission can be performed within the COT. Here, type 2 transmission can have three options based on the gap portion within the COT, which can be shown in Table 14 below. For example, type 2A (LBT cat 2) transmission can set the COT gap to 25us or more, and it can be used to discover burst transmissions. For example, type 2A may be considered for SSB transmission, but is not limited to this. As another example, type 2B transmission may be a type that applies a COT gap of 16us. In addition, type 2C transmission may be a type that applies a COT gap of 16us or less. For example, if the next transmission is at most 16us, idle sensing may not be required and type 2C may be applied.

[0180] [Table 14]

[0181]

[0183] Here, for the aforementioned COT sharing, the gap may be smaller than the OFDM symbol interval. This is because the resource assignment method based on OFDM symbols may not be sufficient, and a method for indicating CP extension may be applied by considering the above problem. That is, it may be indicated to extend the CP faster than the OFDM symbol boundary, and one of the following Table 15 may be indicated.

[0184] [Table 15]

[0185]

[0187] For example, Fig.13 A method of applying CP extension to an uplink when COT sharing is performed between a downlink and an uplink, which is applicable to the present disclosure, is shown. Fig.13 The following example shows a situation where C2 is set to 1 based on COT sharing, with a 16us gap, but is not limited thereto. Fig.13 , the TA value may be considered to ensure a 16us gap between downlink and uplink in the base station. For example, the C value may be set via RRC signaling. In addition, the CP extension for uplink transmission may be indicated in the uplink grant.

[0188] As another example, a case where channel access is performed based on the FBE method can be considered. The FBE method can be a channel occupation method applicable to an area (e.g., a specific building, a factory) where no other system is ensured by rules. Here, in the case where channel access is performed based on the FBE method, transmission can be started at a specific time point. As a detailed example, Fig.14 The semi-static channel access process applicable to the present disclosure is shown. Fig.14 , a single COT may start once every Tx ms. Here, a channel may be occupied when the channel is idle for at least 9us before the COT. Here, Tx ms may be set to one of the values ​​from 1ms to 10ms. Also, the gap may be at least 5% of Tx. Here, COT sharing may be used in a similar manner to LBE, and the gap may be at most 16us.

[0189] For example, Fig.15 A method for performing channel occupation applicable to the present disclosure is shown. Fig.15 , before performing transmission in the operating channel, the device may perform a CCA check in a CCA observation period of not less than 20us based on energy detection. In addition, for example, in the case of sending a control frame (e.g., ACK, block ACK) considering multicast, the CCA process may be skipped, and transmission may be performed immediately after receiving the packet. That is, the UE may perform control frame transmission without a new CCA process, but this will not exceed the maximum COT.

[0190] For example, when the device sends an ACK / NACK signal after receiving data, the device can skip CCA, but this needs to be within the maximum COT. In addition, for example, sending a signal with a maximum duty cycle within 5% of 50ms as an observation period through short control signaling can be performed without CCA, but it may not be limited to a specific form.

[0191] Likewise, for example, LBT categories may be considered. The LBT categories may consider the following categories: Category 1 where transmission is performed immediately after a short switching gap, Category 2 where LBT is performed without random backoff, Category 3 where a fixed-sized contention window and random backoff are performed, and Category 4 where a variable-sized contention window and random backoff are performed.

[0192] In detail, category 1 may be a method of performing transmission immediately after a short switching gap. Here, category 1 may be used to perform transmission immediately after a switching gap within one COT. The switching gap from receiving to sending within one COT may include the switching time of the transceiver and may not be longer than 16us. In addition, for example, category 2 may be an operation of performing LBT without random backoff. For example, in the case of performing LBT, category 2 may be a method of performing an initial CCA, and if the channel is idle, occupying the channel and sending data in an unlicensed channel. Here, random backoff counting may not be performed. On the other hand, category 3 may be an LBT method in which random backoff is performed using a contention window of a fixed size. As a case of performing LBT based on category 3, if the channel is idle by performing an initial CCA, a fixed contention window (e.g., a fixed "q" value, where q represents a value that determines the contention window size of a random N counter selected between 0 and q) may be used to perform random backoff. For example, by reducing the count depending on whether the channel is idle for each ECCA slot, the random backoff operation allows a counter value randomly selected within the contention window to occupy the channel when the value is 0.

[0193] As another example, category 4 may be an LBT method in which random backoff is performed with a contention window of variable size. Category 4 may be different from category 3 because category 4 has a variable contention window. On the other hand, the operation of occupying a channel by applying an N value based on a random backoff value may be the same. That is, category 4 may be the same as category 3, except that the contention window size may be different based on time or event compared to category 3, and may be used in multiple wireless communication systems (e.g., LAA, NR-U, WiFi), but is not limited to a specific embodiment. Here, for example, different channel access categories (e.g., LBT categories) may be defined and used for transmission of other channels / signals within one COT. In addition, for example, in a new wireless communication system (e.g., NR-U), category 4 LBT and category 2 may be used in the COT, which may be as shown in Table 16 below. In addition, in the absence of unicast transmission and the transmission is characterized by limited transmission with transmission within 1 ms or less and its duty cycle is 5% or less, category 2 LBT may be used to discover burst transmissions, but may not be limited to a specific form.

[0194] [Table 16]

[0195]

[0197] Hereinafter, a method for assigning frequency resources is described so that the side link communication (e.g., NR) of a wireless communication system can operate in an unlicensed band. For example, currently, based on SCS, the size of the RB set included in 20MHz in the unlicensed band (e.g., NR-U) of the wireless communication system may be different. For example, for a 15kHz SCS, the size of the RB set may be 100 to 110 PRBs. In addition, for a 30kHz SCS, the size of the RB set may be 50 to 55 PRBs. Here, for example, in the case of assigning interleaving-based RB resources, some interleavings may include 11 PRBs, but the remaining interleavings may include only 10 PRBs.

[0198] Here, for example, a case where the size of the subchannel is changed to use the entire bandwidth in the side link can be considered. That is, a case where the number of PRBs included in each subchannel is set differently can be considered. However, in the case where different subchannel sizes are set, if retransmission is performed after the initial transmission of a TB with the same transport block size (TBS), it may be difficult to guarantee the transmission. In view of the above, the subchannel size (i.e., the number of PRBs) in each subchannel may be set to the same, but may not be limited thereto. However, if the subchannel size is set to the same in each subchannel, some subchannels may not be used in a single interleaving based on the interleaved RB resource configuration.

[0199] Here, for example, Fig.16 A method for setting an RBS in a resource pool and a BWP in a side link unlicensed band to which the present disclosure can be applied is shown. The frequency domain resource structure of a wireless communication system of a side link unlicensed band (e.g., NR SL-U) can consider a bandwidth part (BWP), a resource pool (RP), an interleaved RB, and an RBS (RB set). Here, the RBS can be considered even in a wireless communication system of an unlicensed band (e.g., NR U), and it is not limited to a specific embodiment.

[0200] refer to Fig.16, a single sidelink unlicensed band (SL-U) BWP 1610 may be configured in the sidelink UE, a single SL-U RP 1620 may be configured in the SL-U BWP 1610, and two RBSs 1631 and 1632 may be configured in the SL-U RP 1620. However, this is merely an example for describing clarity and is not limited to the above embodiments. Here, for example, in the SL-U system, an interleaving structure may be considered to meet the OCB and PSD requirements required in the unlicensed band. That is, in the SL-U system, a sidelink interleaving structure may be implemented by performing CRB indexing based on point A which is a reference frequency point of a single carrier. Fig.16 In the example, the frequency domain corresponding to CBR index 47 to CRB index 90 may be configured as SL-U BWP 1610 based on the configuration of SL-U BWP 1610, and the frequency resources including two RBSs 1631 and 1632 may be configured based on the configuration of SL-URP 1620, but this is only an example and may not be limited thereto. Fig.16 The frequency domain resource configuration method of the SL-U system and the resource assignment method for actual SL-U data transmission based on the method are shown.

[0201] For example, in the channel access process of the sidelink unlicensed band wireless communication system (e.g., NR SL-U), the above-mentioned type 1 channel access process and type 2 channel access process can be applied. In addition, for example, UE-to-UE COT sharing can be applied to UEs operating in the sidelink unlicensed band. That is, a single Tx UE can share a portion of the unlicensed resources acquired through the LBT process with an Rx UE or another UE.

[0202] For example, as in the existing sidelink wireless communication system (NR SL), frequency resources can be configured based on subchannels in a wireless communication system (e.g., NR SL-U) of a sidelink unlicensed band. That is, the term "subchannel" can be used even in NR SL-U, as in NR SL. However, the name of the subchannel may be configured differently in a wireless communication system (e.g., NR SL-U) of a sidelink unlicensed band and is not limited to a specific embodiment. For clarity of description, the following description is based on subchannels.

[0203] For example, a single interleaving-based RB structure that meets the above-mentioned unlicensed band requirements can be defined as M RBs in the frequency domain. Here, the interleaving-based RB structure can be defined as RBs with intervals corresponding to a uniform number of RBs. As another example, the interleaving-based RB structure can be configured using RBs with intervals corresponding to a non-uniform number of RBs, and is not limited to a specific embodiment.

[0204] Here, the interleaving-based RB structure can be pre-configured for the NR SL UE in a cell-specific or carrier-specific manner based on the configuration based on the bandwidth / digital parameters. As another example, the interleaving-based RB structure can be specifically configured in the physical link between the UEs through a higher layer configuration, and is not limited to a specific embodiment. Here, the interleaving-based RB structure can be applied to all interleavings regardless of the carrier bandwidth. Therefore, the interleaving-based RB structure can be configured based on the CRB defined based on point A, where point A is a specific reference point in the frequency domain. Here, a single subchannel can be defined as being pre-configured with k interleavings. As another example, a single subchannel can be configured with k interleavings through higher layer signaling. K can be the number of interleavings for each subchannel. The number of interleavings for each subchannel can have a fractional (or decimal value) or an integer value, which will be described below. In addition, for example, when multiple RBSs are configured within a single SL BWP, the frequency resource assignment indication may include RBS assignment information and RB frequency resource assignment information based on subchannels or interleavings.

[0205] As another example, resource assignment can be performed based on an interleaved RB unit rather than a "subchannel" unit in a sidelink unlicensed band system (e.g., NR SL-U). Here, the frequency resource assignment unit can be based on an interleaved RB unit rather than an existing subchannel, but this is merely an example and is not limited to a specific embodiment.

[0206] In the following, both the subchannel unit and the interleaving-based RB unit can be considered as a resource allocation unit in the frequency domain. Here, the subchannel can be configured with k interleavings or can be configured with a number of continuous RBs. However, in the following, for the sake of clarity of description, the "subchannel unit" based on the interleaving structure is described as a unit of frequency resource assignment. However, by applying the proposed method, frequency resource assignment can also be configured using an interleaving-based RB unit instead of a subchannel unit, and is not limited to a specific form.

[0207] Here, for example, Fig.17 The present disclosure is applied to a method for configuring a side link unlicensed band resource pool based on continuous frequency resources. Fig.17 , the side link unlicensed band resource pool 1710 may be configured based on continuous frequency resources. Here, the side link unlicensed band resource pool 1710 may be indicated using only the RBS index. Fig.17, the case where only a single RBS 1720 is configured in the sidelink unlicensed band resource pool 1710 while the LBT process in the unlicensed band is considered. Here, the resource pool configuration of the sidelink unlicensed band can be indicated to the UE based on continuous frequency resources (hereinafter, case 1). For example, in order to meet requirements such as OCB and PSD in the aforementioned unlicensed band, most frequency resources (e.g., >80%) within at least one LBT BW (RBS 1720) can be configured to a single resource pool. In view of the above provisions, there may be limitations on configuring at least one resource pool for a single RBS within a single SL BWP. That is, only a single resource pool can be configured to exist within a single RBS and include most frequency resources. In this way, the above provisions can be met. Here, for example, resources for actual transmission can be selected from a resource pool configured based on continuous frequency resources by assigning resources based on interleaving frequency, thereby performing sidelink transmission.

[0208] on the other hand, Fig.18 The present disclosure is applied to a sidelink unlicensed band resource pool configuration based on frequency resources using interleaved assignment. Fig.18 In order to meet the regulations on frequency utilization in unlicensed bands, the resource pool can be configured using the interleaved RB-based subchannels or new interleaved RBs from the initial resource pool configuration phase. That is, the interleaved RBs or the interleaved RB-based subchannels can be used according to the resource pool configuration. For example, refer to Fig.18 , in the case of configuring a frequency resource-based sidelink unlicensed band resource pool using interlace assignment, the frequency resources used for the resource pool configuration may be indicated based on a combination of RBS and interlace / subchannel index (hereinafter, Case 2).

[0209] That is, in Fig.18 In order to meet the requirements such as the above-mentioned OCB and PSD, the resource pools 1821 and 1822 may be configured using the interleaved RB-based subchannels or interleaved RBs from the initial resource pool configuration phase. Therefore, the resource pools 1821 and 1822 of the sidelink unlicensed band may not have a continuous subchannel or PRB structure. That is, since the resource pools 1821 and 1822 of the sidelink unlicensed band may be configured in non-contiguous PRBs based on interleaved assignment, the requirements such as the above-mentioned OCB and PSD may be met. In addition, compared with case 1 ( Fig.17 ), multiple resource pools for the side link unlicensed band can be configured even in a single RBS, and thus, flexibility in resource configuration can be provided.

[0210] Here, all resource pool configuration methods corresponding to the above-mentioned cases 1 and 2 may consider the frequency resource assignment method based on interleaving. However, in the operation of configuring a single resource pool, there may be differences regarding whether the frequency resources are configured as continuous frequency resources (similar to the existing NR SL) (case 1) or whether a discontinuous resource pool is configured from the resource pool configuration stage considering the interleaving structure (case 2). Below, the RBS-based sidelink unlicensed band resource pool configuration method is described based on the above content.

[0211] Fig.19 A side link unlicensed band resource pool configuration method applicable to the present disclosure is shown.

[0212] The sidelink unlicensed band resource pool can be configured based on the RBS. For example, the sidelink resource pool can be configured by the resource pool starting point and the number of subchannels within the resource pool based on consecutive subchannels. For example, as described above, for the sidelink unlicensed band pool, the resource pool corresponding to the LBT BW can be configured by the resource pool starting point and the number of subchannels within the resource pool based on consecutive subchannels. In order to effectively configure the sidelink unlicensed band resource pool, RBS configuration and indexing can be considered. That is, the sidelink unlicensed band resource pool can configure a single resource pool by indicating the RBS configuration / index via resource pool configuration signaling.

[0213] In detail, for example, a single resource pool may be configured with one or more RBSs. Therefore, a specific resource pool may perform frequency configuration for the resource pool by providing a continuous RBS index configuration associated with the specific resource pool. Here, in the case where the frequency configuration of the resource pool is performed based on a continuous RBS index configuration, the resource pool may utilize the gap band resources between the RBSs to maximize the frequency resource efficiency. Consider the case where four RBSs are configured within a side link BWP. Here, since the gap bands between the RBSs can be configured, three gap bands can be configured and provided. Here, the resource pool of the side link unlicensed band may be configured by continuous RBS indexes based on the LBT BW. In detail, the frequency domain resource configuration in a single resource pool configuration may be provided by RBS index information. For example, the frequency domain resource configuration in a resource pool configuration may be provided by information about the starting RBS index and the number of continuous RBSs.

[0214] refer to Fig.19, in configuration 0 1910, the resource pool may be configured with four consecutive RBSs from RBS#0 to RBS#3. Here, configuration 0 1910 may indicate the resource pool configuration by indicating RBS#0 as the starting RBS index and the number of consecutive RBSs 4. As yet another example, in configuration 1 1920, as two consecutive RBSs, RBS#0 and RBS#1 may be configured to side link resource pool #0, and RBS#2 and RBS#3 may be configured to side link resource pool #1. Here, configuration 1 may indicate the resource pool configuration by indicating RBS#0, RBS#2 as the starting RBS index and the number of consecutive RBSs 2 for each resource pool. As yet another example, in configuration 2 1930, side link resource pool #0 may be configured to RBS#0, side link resource pool #1 may be configured to RBS#1, side link resource pool #2 may be configured to RBS#2, and side link resource pool #3 may be configured to RBS#3. Here, since each resource pool corresponds to each RBS, the corresponding RBS index and the number of RBSs 1 may be indicated. As another example, in configuration 3 1940, side link resource pool #0 may be configured to RBS#0, side link resource pool #1 may be configured to RBS#1 and RBS#2, and side link resource pool #2 may be configured to RBS#3. Here, the starting RBS index and the number of RBSs corresponding to each side link resource pool may be indicated, and through this, the configuration of each resource pool may be indicated. As another example, in configuration 4 1950, side link resource pool #0 may be configured to RBS#0, RBS#1, and RBS#2, and side link resource pool #1 may be configured to RBS#3. Here, the starting RBS index and the number of RBSs corresponding to each side link resource pool may be indicated, and through this, the configuration of each resource pool may be indicated. However, Fig.19 The resource pool configuration is merely an example and may not be limited to the above-described embodiments.

[0215] Here, for example, when a plurality of RBSs are configured in the SL BWP, frequency resource information of a resource pool configuration for a sidelink unlicensed band may be indicated to the UE through at least one of interlace / subchannel-based configuration information and RBS configuration information.

[0216] Here, when all interleaving / subchannel-based configuration information and RBS configuration information are provided, frequency resource configuration information for a single resource pool may be provided to the UE via cross-frequency resource information. In addition, when an intra-cell guard band (GB) between consecutive RBSs is configured in a single resource pool, the frequency resources corresponding to the GB may be used as part of the resource pool for sidelink unlicensed band communications.

[0217] Below, the method for assigning frequency resources for sidelink unlicensed band data transmission and reception in the frequency domain is described above. The contents described below can all be applied to the method for configuring a resource pool according to at least one of the interleaving / subchannel-based configuration information and the RBS configuration information, and are not limited to a specific embodiment.

[0218] In addition, for example, the following description may apply to all of the following cases: a case where continuous frequency resources are configured into a single resource pool (case 1) and a case where the resource pool is configured based on discontinuous frequency resources (case 2). However, although for clarity of description, the description is made based on the case where a single resource pool is configured based on continuous frequency resources (case 1), these descriptions may also be interchangeably applied to the case where the resource pool is configured based on discontinuous frequency resources (case 2), and may not be limited to a specific form.

[0219] For example, the frequency resource configuration of the sidelink unlicensed band can be performed based on the starting subchannel information and the number of continuous subchannels based on the continuous frequency resources. In addition, for the time resource configuration of the sidelink unlicensed band, the resource pool can be configured by applying a bitmap between the remaining time slots based on the SSB transmission time slot, the reserved time slot, and the TDD UL-DL configuration, and may not be limited to a specific embodiment.

[0220] However, the following description is made based on the frequency resource configuration of the side link unlicensed band. For example, the indication of the side link resource block set (SL RBS) index (i.e., the bit size) may be configured taking into account the total number of SL RBSs included in a single SL BWP. Here, the indication of the SL RBS index may indicate one or more SL RBS indexes. For example, the SL RBS may always be configured continuously in the frequency domain, but may not be limited thereto. Here, for clarity of description, the following description is made based on the SL RBSs configured continuously in the frequency domain.

[0221] In addition, for example, frequency resource reservation can be indicated by a physical sidelink control channel (PSCCH). Here, frequency resource reservation indication can be performed in the second time slot or the second time slot / third time slot based on the PSCCH received within the lowest interleaving index among the interleaving indexes defined within the single carrier bandwidth. As described above, based on the LBT BW considered in the unlicensed band, the interleaving structure can be set to 10 interleavings (ie, M=10) in 15kHz SCS, and can be set to 5 interleavings (ie, M=5) in 30kHz SCS, as described above. In detail, based on the LBT BW being 100 to 110 RBs in 15kHz SCS and 50 to 55 RBs in 30kHz SCS, a single RBS is configured by the number of RBs, and the interleaving structure can be configured as described above.

[0222] That is, in the case of 15kHz SCS, some resources (ie, RBs) of the same interlace may exist once in every 10 RBs. However, the interlace value may be configured with different values ​​based on at least one of different RBS sizes (LBT BW), SCS, and the number of RBs constituting a single interlace, and may not be limited to a specific embodiment.

[0224] <Issue 1. Proposal on TBS determination method for PSSCH in NR-SL-U system>

[0225] In an existing wireless communication system (e.g., R16 NR SL system), considering the TBS table (conventional table, URLLC destination table) configured for the PSSCH assigned by SCI, the UE operation is defined as determining which TBS value in the indicated TBS table.

[0226] On the other hand, unlike the existing SL system, in the NR SL-U system, there are many standard technologies that are newly designed taking into account the various rules required in unlicensed channels and channel environments and the characteristics in unlicensed bands. For NR SL operations in unlicensed bands, it is expected to consider new physical channel structures, such as various time slot structures, channel transmission methods, new resource assignment methods, LBT applications, mini time slot structures, and dynamic PSFCH resource structures. Therefore, it is necessary to introduce a new method to rate match PSSCH transmissions. The present invention proposes a method for determining the TBS for PSSCH transmission taking into account the new NR SL-U system.

[0227] The UE initially needs to determine the number of REs assigned for PSSCH transmission in a single time slot. Here, the UE initially needs to determine the number of REs assigned for PSSCH transmission in a single time slot (N′ RE ), which can be shown as Equation 6 below.

[0228] [Equation 6]

[0229]

[0231] For example, in Equation 6, can be 12, and It can be SL-Length Symbols-2: SL_Length_Symbols higher layer parameter. In addition, if the "PSFCH Overhead Indication" field of SCI format 1-A indicates "1", then It can be 3, otherwise it can be 0. (For sl-PSFCH-period = 2 or 4), if sl-PSFCH-period = 0, If sl-PSFCH-period = 1, then

[0232] In addition, for example, It can be the overhead given by the higher layer parameter "sl-X-Overhead". It can be determined by the higher layer parameter "sl-PSSCH-DMRS-TimePattern" as shown in Table 17 below.

[0233] [Table 17]

[0234]

[0236] The UE may determine the total number of REs assigned to the PSSCH, which may be as shown in Equation 7 below.

[0237] [Equation 7]

[0238]

[0240] Here, n PRB Indicates the total number of PRBs allocated to PSSCH, indicates the total number of REs occupied by PSCCH and PSCCH DMRS, and represents the number of coded modulation symbols generated for the 2nd SCI transmission under the assumption of γ=0, for example, in the case of 2-layer transmission, the number of symbols before duplication, but is not limited thereto.

[0241] Based on the total number of REs of the PSSCH determined above, the UE determines the TBS by performing steps 2), 3) and 4) shown in Table 18.

[0242] [Table 18]

[0243]

[0246] Basically, when determining TBS, the difference between the target coding rate indicated by the MCS and the actual coding rate (TBS ratio compared to the amount of resources actually used) needs to be minimized. In addition, in the present invention, whether the overhead that may occur in each of the multiple time slots in which a single TB is transmitted is deterministic or uncertain is also considered to be an important factor in determining TBS. From this point of view, it is necessary to design a new TBS determination method considering the newly considered operations or technologies of NR SL-U. A specific processing method is proposed below.

[0247] References to the signaling proposed below may refer to the 1st SCI or the 2nd SCI, higher layer signaling may refer to signaling from layers above the PHY layer including the MAC or RRC layer, and “pre-configuration” may also be collectively referred to as higher layer configuration.

[0249] Discussion on PSSCH TBS Determination

[0250] Basically, RAN1 does not consider the case where the UE has a different TBS between the initial transmission and the retransmission (final RAN1 #100 protocol).

[0251] In the case of Uu, the gNB can always identify the PDCCH reception status of the UE. Therefore, the gNB can ensure that the TBS remains the same between initial transmission and retransmission. That is, the base station can adjust the UE to have the same TBS using the TBS calculation equation or a method of reusing the previous TBS so that the UE can always determine the same TBS.

[0252] On the other hand, in the case of SL, the Tx UE may sometimes not be able to identify information about the PSCCH decoding status of the Rx UE. For example, in the case of blind HARQ retransmission and only NACK feedback, it is difficult for the Tx UE to verify the accurate PSCCH reception status. Therefore, in this case, in the current standard, the UE determines the TBS only through the TBS calculation equation.

[0253] In the existing SL, MCS, PSFCH presence status and SL RS (DMRS, PT-RS) can be modified in various ways between initial transmission and retransmission. Therefore, in order to determine the TBS, the number of reference REs needs to be determined. For example, the PSFCH overhead indicator, the average DMRS over the configured patterns, and the configured overhead of each resource pool are all taken into account to ensure that the same TBS is determined. On the other hand, a certain degree of flexibility in Tx parameters must be ensured.

[0254] The gamma value is usually a value considered so that the second SCI has a PRB-level mapping granularity. That is, the actual second SCI may not be an integer multiple of the PRB unit.

[0255] In some cases, it may be difficult for the Tx UE to adjust the 2nd SCI RE mapping according to the resource pool level configuration (eg, the PSFCH period affecting the time domain DMRS pattern and the corresponding 2nd SCI RE mapping).

[0256] Considering different channel conditions and speeds, the DMRS pattern in the initial transmission and the DMRS pattern of the retransmission can be different. Moreover, since the PT-RS is determined based on the DMRS pattern, it can be modified similarly. The problem with this is that it leads to different gamma values ​​and therefore different TBS. →When determining the PSSCH TBS, the gamma value is set to 0 for calculation.

[0259] Design Issue 1. Determine the operation of PSSCH TBS by considering the existence of various gaps / AGC symbols to determine the number of PSSCH transmission symbols

[0260] In the conventional NR SL system, the gap symbols used for AGC and Tx-Rx switching are always excluded from the PSSCH transmission symbols. This is because the corresponding symbols exist in all PSSCH slots (in the case of non-PSFCH slots).

[0261] On the other hand, as shown in the above figure, in the NR SL-U system, transmission needs to be maintained for a period longer than the short gap time (for example, a 16μs or 25μs gap) to avoid another transmission node taking over the unlicensed channel during the COT duration after a successful LBT. The AGC / gap symbols present in the existing SL time slot structure are provided on the first OFDM symbol and the last OFDM symbol (if there is no PSFCH). In addition, in time slots where additional PSFCH resources are present, additional overhead occurs due to PSFCH transmission. The above figure shows a case where the transmission of at least the SL RS associated with the PSCCH / 2 second SCI / PSSCH is generally performed for each time slot. In this case, since there is no SL transmission in the time corresponding to the AGC (@OFDM Symbol#0) / gap (@OFDM Symbol#13) symbol, the occupied resources of the corresponding unlicensed channel can be taken away by other transmission nodes. To prevent this, NR SL-U can apply CP extension (CEP) similar to the existing NR-U, that is, this is a method of further extending the CP length of the previous OFDM symbol and using LS transmission to fill the empty time space within the AGC or gap symbol. The left side of the above figure shows an example of applying this operation. For example, in order to maintain the resources occupied in the last gap symbol (a normal time slot with a normal CP based on OFDM symbol number 13), transmission can be performed in advance in part or all of the time of the corresponding gap symbol by extending the CP of the first OFDM symbol (OFDM#0, green symbol) of the next time slot.

[0262] In addition to this method, a method of performing SL transmission on the corresponding AGC or gap symbol is to use the PSSCH RM method. That is, in order to use the resources on the corresponding symbol more efficiently, it can be used as a resource for PSSCH transmission. This method basically assumes the transmission of side link channels / signals, such as continuous PSSCH / PSCCH / second SCI. That is, after a successful LBT, the Tx UE can maintain the transmission of the side link channel / signal in continuous time slots during the COT duration, and can avoid performing unnecessary LBT processes. Therefore, there is an advantage that the channel utilization efficiency of the entire unlicensed band is improved and a positive impact can be provided to other RAT systems. Moreover, there may be some disadvantages that the PSSCH RM operation becomes somewhat complicated. However, considering the performance improvements that can be achieved through additional regulatory modifications, these methods can be fully considered.

[0263] That is, unlike the existing SL, whether the AGC / gap symbol exists in SL-U is unstable, so the TBS can be determined by various methods, such as a method that can indicate the presence or absence of overhead or assume the presence of specific overhead.

[0264] As described above, the method of processing or utilizing AGC / gap symbols leads to structural changes in the existing PSSCH TBS determination method. Hereinafter, the present invention proposes the following specific method.

[0266] Fig. 20 It may be applicable to CPE and PSSCH RM operation of the sidelink unlicensed band of the present disclosure.

[0267] AGC / gap symbol overhead processing method:

[0268] The UE needs to determine the number of REs (N′) assigned for PSSCH transmission within a single PRB. RE ). If interlace-based resource assignment is configured or determined for PSSCH transmission, the UE may determine the number of REs assigned for PSSCH transmission based on a single PRB within an interlace, which may be as shown in Equation 8 below.

[0269] [Equation 8]

[0270]

[0272] For the methods defined in the existing SL system, a new processing method for the SL-U system is proposed as follows.

[0274] ○Method 1. On the other hand, if AGC / gap symbols are used for PSSCH transmission by PSSCH rate matching (RM) without applying CPE, whether to use the corresponding AGC / gap symbols can be semi-statically indicated / determined by dynamic or higher layer configuration through SCI signaling (1st SCI or 2nd SCI), which is different from the existing method. This signaling is actually a value for Rx UE rather than Tx UE, and is assumed to be a value known from the perspective of Tx UE as determined by Tx UE. That is, according to the dynamic or higher layer configuration, the AGC / gap symbols that are always excluded from the PSSCH transmission symbols in the existing PSSCH RM operation can be used as additional PSSCH transmission symbols through the above-mentioned SCI signaling (1st SCI or 2nd SCI), and can be applied to the PSSCH TBS determination method.

[0275] Alt1

[0276]

[0278] Alt2

[0279]

[0281] here, Refers to the value that reflects the presence or absence of AGC and / or gap symbols through the proposed signaling. If it is determined by a higher layer parameter of the UE or UE scheduler, the number of PSSCH transmission symbols can be calculated by determining whether AGC / gap exists in a single time slot according to the determined value. For example, for Of the values, one of {0, 1, 2} may be selected and indicated. Of course, if additional configurations within a single time slot (e.g., PSFCH transmission status) are considered, values ​​greater than 2 may also be applied. The value of .

[0282] Similarly, as shown in Alt 2) above, the value of the number of symbols for the AGC and gap symbol presence states ( and ) may be separately indicated and may be separately determined independently to determine the number of symbols used for sidelink transmission. For example, depending on the scheduling of the Tx UE, all, one, or none of the AGC and / or gap (Tx-Rx switching) symbols may appear in each time slot. Therefore, depending on such a scheduling method, SCI signaling for information may be required.

[0283] As another example, in case that SL transmission resources are indicated based on a configured grant, the above-mentioned AGC / gap related information may be provided based on higher layer parameters.

[0284] In case of SCI signaling, a new field corresponding to 1 bit or 2 bits may be configured and defined within the 1st SCI or 2nd SCI format.

[0285] sl-LengthSymbols: It is a higher layer parameter and the number of OFDM symbols used for SL transmission within a single slot.

[0287] ○Method 2

[0288] The Tx UE can determine the The new sl_unlicensed-LengthSymbols value reflects the AGC / slot symbol usage status and / or non-slot-based PSSCH transmission in advance to determine the PSSCH TBS. That is, the sl-LengthSymbols parameter as a higher layer parameter can be replaced by the new sl_unlicensed-LengthSymbols.

[0290] Alt 3

[0291]

[0293] ○Method 3

[0294] For a TB transmission, from the perspective of having a certain amount of overhead between the initial transmission and subsequent retransmissions, we can define the “number of reference symbols” " and applies it to the PSSCH RM operation. The number of reference symbols It is not the number of AGC or gap symbols actually used, but is determined based on the total average value or maximum / minimum value according to the time slot, SCI signaling or higher layer configuration. In this way, PSSCH RM is performed. As described above, the number of reference symbols that can be provided by the SCI signaling described here refers to the signaling for the Rx UE, and the Tx UE determines the value of the number of symbols by itself, so there is no need to receive the signaling.

[0296] -Number of reference symbols

[0297] ○ Each single COT

[0298] In this case, it can be regarded as a reference value determined based on the average overhead of the AGC / slot symbols of the time slots present in a single COT. That is, the PSSCH transmission symbol of a TB transmission can be determined by considering the overhead (number of symbols) of the reference AGC / slot symbol in the corresponding COT.

[0299] ○ Per single resource pool, per single carrier / BWP, and / or per single RBS

[0300] In this case, it may be considered as a reference value determined based on the average overhead of AGC / slot symbols of time slots existing within a single resource pool, carrier / BWP and / or RBS.

[0302] - The Tx UE may determine the number of independent reference symbols to perform PSSCH TBS determination, and may be configured by a higher layer parameter. Of course, the Tx UE performs PSSCH RM, and performs decoding based on a value indicated by the Tx UE through SCI signaling or configured by a higher layer.

[0303] Fig.21 PSSCH assignment and AGC / gap existence status for various SL-U scheduling and channel occupancy scenarios applicable to the present disclosure are shown.

[0305] Case 1) TxUE->RxUE#1 and Tx UE->Rx UE#2

[0306] After the sidelink transmission (PSSCH / PSCCH / second SCI) for Tx UE->Rx UE#1 and the LBT process performed by the Tx UE are successfully performed, the Tx UE performs sidelink transmission to Rx UE#1 on two consecutive time slots. Moreover, the Tx UE performs sidelink transmission to Rx UE#2 on two consecutive time slots. There may be no gap symbol between two consecutive time slots respectively transmitted to the Rx UE. In this case, when determining the TBS for PSSCH transmission, the lack of the corresponding gap symbol can be considered by the proposed method.

[0308] Case 2) In case of single TTI scheduling Tx UE->Rx UE#1

[0309] Similar to case 1, the Tx UE can send four PSSCHs to a single Rx UE#1 on four consecutive time slots after a successful LBT. In this case, since it can be determined whether there is an AGC and / or gap symbol within each time slot as shown in the figure, the proposed method of determining TBS taking into account these characteristics can be applied.

[0311] Case 3) TxUE with multi-TTI scheduling->Rx UE#1

[0312] Unlike case 2 above, the Tx UE can perform multiple TB transmissions to the Rx UE through one SCI signaling. In this case, as shown in the figure, after a successful LBT, although AGC is performed only in the first slot of PSSCH, the gap symbol of Tx-Rx switching can only exist in the last PSSCH transmission slot. The PSSCH TBS can be determined by the proposed method reflecting this.

[0314] A PSSCH symbol determination method considering LBT results

[0315] In addition to the PSSCH symbol determination method that takes into account the presence of dynamic AGC / gap symbols, non-slot-based PSSCH / PSCCH transmissions instead of slot-based PSSCH / PSCCH transmissions can also be considered. This is because, as shown in the following figure, whether the LBT performed for channel occupancy in an unlicensed band is successful does not always occur at the slot boundary, but can occur at any point in the middle. Therefore, PSSCH / PSCCH transmissions can be performed from a random OFDM symbol index in the middle of a slot to make it possible to occupy the channel immediately after a successful LBT.

[0316] In terms of determining TBS, this transmission method is completely different from the existing PSCCH / PSSCH assignment, so this characteristic needs to be taken into account to determine the TBS.

[0317] Fig. 22 A PSSCH suitable for use in the present disclosure is shown.

[0318] If, in addition to the PSSCH symbol determination method (which takes into account the dynamic AGC / gap symbol presence status), PSSCH transmission is also considered to consider information about the COT duration, an additional PSSCH symbol determination method can be applied. The following equation is one of the equations proposed in Topic 1, and different equations can be applied according to Topic 1. However, it is described here only as an example. If additional positions can be considered at the beginning of PSSCH transmission considering the LBT result, instead of only fixing the time slot boundaries at all times, the method proposed below can also be considered in addition. Here, a method of using sl-Length Symbols values ​​differently is proposed.

[0319]

[0321] Method 1) Use the same number of non-slot-based PSSCH transmission symbols as PSSCH#0 provided by SCI signaling The sl_length_symbols value may be determined by SCI signaling.

[0323] Method 2) Through SCI signaling, the PSSCH transmission symbols of time slot n and time slot n+1 (i.e., non-time slot-based and based The average value of the transmission of the time slot) is used for the PSSCH transmission symbol. This value can also be sent by the Tx UE to the Rx UE through SCI signaling or Configured through higher level parameters for each resource pool.

[0325] Method 3) Through SCI signaling, the PSSCH transmission symbols for time slot n and time slot n+1 (i.e., not based on time slot The maximum value of the two (and slot-based transmission) is used for the PSSCH transmission symbol. This value can also be passed from the Tx UE to the Rx UE. SCI signaling or configured through higher layer parameters for each resource pool.

[0327] Design Topic 2.PSSCH DMRS Overhead Status

[0328] In order to minimize the need for the Tx UE to perform the LBT process, a method can be considered that schedules transmissions with large data sizes and performs transmissions at times in consecutive time slots during the period of occupying the channel when one LBT is successful. In the existing SL system, it is possible to perform data transmission scheduling for only one TB transmission in multiple time slots through one SCI signaling. On the other hand, as shown in the figure, it can be considered to perform scheduling of multiple TB transmissions in multiple consecutive time slots through one SCI signaling considering the probability of opportunistic resource utilization in the unlicensed band.

[0329] That is, the Tx UE may consider a method of scheduling one or more TB transmissions in multiple time slots through one SCI signaling to the same Rx UE(s) in the SL-U system. This resource assignment method may minimize the LBT execution of the Tx UE and may open up opportunities that can improve additional spectrum efficiency.

[0330] Fig.23 PSSCH DMRS overhead control considering multi-TTI scheduling in SL-U applicable to the present disclosure is shown.

[0331] When this resource assignment method is configured and scheduling is indicated, the Tx UE can open up the opportunity to potentially remove the existing overhead sent for each time slot. From the perspective of PSSCH DMRS, when data TB transmission is performed on the same Rx UE on multiple time slots, the DMRS overhead can be reduced in some time slots. In particular, when considering the scenario of utilizing unlicensed bands, the mobility of UEs performing sidelink transmission and reception in unlicensed bands is restricted.

[0332] The UE may determine the number of REs (N′) assigned for PSSCH transmission within a single PRB. RE ), which can be shown as shown in Equation 9 below.

[0333] [Equation 9]

[0334]

[0336] For example, in Equation 9, can be 12, and It can be sl-LengthSymbols-2: sl-LengthSymbols higher layer parameters. In addition, if the "PSFCH Overhead Indication" field of SCI format 1-A indicates "1", then It can be 3, otherwise it can be 0. (For sl-PSFCH-Period = 2 or 4), if sl-PSFCH-Period = 0, then If sl-PSFCH-Period = 1, then

[0337] In addition, for example, It can be the overhead given by the higher layer parameter "sl-X-Overhead". It can be determined by the higher layer parameter "sl-PSSCH-DMRS-TimePattern" as shown in Table 19 below.

[0338] [Table 19]

[0339]

[0341] The existing PSSCH DMRS RE is considered as an overhead within a single PRB and is omitted from the number of REs of the PSSCH transmission resource. In fact, the existing SL system can also perform PSSCH scheduling for each time slot, and different DMRS mapping modes can be indicated for each time slot through each SCI signaling. However, the DMRS mapping mode is indicated differently according to the mobility or channel environment of the UE and according to its scheduling, and is therefore a stable resource when determining the TBS.

[0343] Method 1

[0344] An additional DMRS pattern is configured within the higher layer parameter sl-PSSCH-DMRS-TimePattern, which configures the DMRS as stable. At least no DMRS pattern Can be added to parameters and configured in the table above.

[0346] Method 2

[0347] The value of can be determined based on the SCI field value indicating the PSSCH DMRS pattern using the DMRS pattern actually used. That is, different PSSCH DMRS and actual DMRS overhead values ​​can be applied to determine the TBS of each time slot.

[0349] Method 3

[0350] Determine the reference DMRS pattern based on the DMRS pattern indicated by the first SCI signaling That is, the reference DMRS pattern can be indicated by SCI signaling to determine the TBS instead of the DMRS pattern used for actual PSSCH decoding. Therefore, the actual PSSCH DMRS mapping pattern and the DMRS mapping pattern considered for determining the TBS may be different. The DMRS assignment pattern considered for TBS determination is defined as the reference DMRS assignment pattern and is used to determine the TBS.

[0352] Design Issue 3.PSCCH / PSCCHDMRS Overhead Status

[0353] The UE finally considers the number of REs per RB, N′ RE, the number of scheduled RBs and the related SCI overhead determine the total number of REs assigned to the PSSCH, which can be shown in Equation 10 below.

[0354] [Equation 10]

[0355]

[0357] For example, PRB Indicates the total number of PRBs assigned to PSSCH, indicates the total number of REs occupied by PSCCH and PSCCH DMRS, and Indicated in The number of coded modulation symbols generated for the 2nd SCI transmission under the assumption of , for example, the number of symbols before duplication in the case of 2-layer transmission.

[0358] Here, the total number of REs occupied by PSCCH and PSCCH DMRS is different from the existing case, and PSCCH may not exist in all SL slots. That is, depending on the configured scheduling method, it is difficult in SL-U to always assume the same PSCCH overhead for PSSCH transmission in multiple schedulings of the same TB. For example, using Fig.18 and 19 , when multi-TTI scheduling is used, PSCCH transmission associated with one TB transmission may be performed in some of all PSSCH transmission slots or in only one slot. That is, PSCCH transmission that schedules multiple PSSCHs for transmission on multiple slots associated with one TB transmission may be performed in some of multiple slots or in only one slot. In this case, an improved technique needs to be applied to the formula for determining the PSSCH TBS.

[0359] LBT success status (RBS unit success status)-whether PSCCH exists can vary depending on whether LBT is successful for each configured RBS. Or, if LBT is successful in at least one RBS, it involves whether it exists only in one RBS or also in another RBS.

[0361] When multi-TTI scheduling is configured or indicated,

[0362] ● Method 1

[0363] PSCCH / PSCCH DMRS overhead is determined using a value calculated as an average value in the scheduled PSSCH transmission slots.

[0364] ● Method 2

[0365] PSCCH / PSCCH DMRS overhead The PSCCH / PSCCH DMRS overhead value determined by higher layer parameters is used.

[0367] If LBT is additionally successful in one or more consecutive RBSs (as shown in the figure below), additional PSCCH overhead is calculated by considering whether PSCCH duplication is applied.

[0368] ● In addition to these methods, PSCCH / PSCCH DMRS additional overhead in the frequency domain The PSCCH replication times will be increased. Therefore, it is reflected in the calculation of PSCCH / PSCCH DMRS overhead. superior.

[0369] Fig.24 A PSCCH replica assigned to an RBS and transmitted is shown, which is applicable to the present disclosure.

[0371] Design Issue 4.PSFCH Overhead Status

[0372] The UE needs to determine the number of REs (N′) assigned for PSSCH transmission within a single PRB. RE ), which can be shown as Equation 11 below.

[0373] [Equation 11]

[0374]

[0376] For example, if the "PSFCH Overhead Indication" field of SCI format 1-A indicates "1", then It can be 3, otherwise it can be 0. (For sl-PSFCH-Period = 2 or 4), if sl-PSFCH-period = 0, then If sl-PSFCH-period = 1, then

[0377] As another example, It can be 3.

[0379] Unlike the existing SL PSFCH transmission period configuration, if LBT is successful, PSFCH transmission and reception can be performed based on the SCI trigger in the SL-U. That is, instead of considering the PSFCH overhead through the SCI indication in the PSFCH resources periodically configured by the higher layer, the PSFCH transmission in a specific time slot can be considered together with the SCI trigger, and the higher layer does not perform PSFCH resource configuration, or based on the PSFCH transmission resources can be configured in a specific time slot within the COT.

[0380] In this case, unlike the existing method of accurately verifying the PSFCH overhead through higher layer parameters and SCI signaling, various types of PSFCH transmission methods can be considered according to the LBT results and the proposed PSFCH resource configuration and SCI indication method.

[0381] If at least one PSFCH transmission per time slot is performed in SL-U, it is necessary to exclude it from the number of REs assigned to PSSCH transmission by increasing the number of PSFCH transmission symbols.

[0383] Design Issue 5. SLSSB Existence Status

[0384] The existing SL does not consider SL-SSB transmission within the resource pool. On the other hand, if LBT is successful, SL-SSB transmission is also possible in SL-U, so SL-SSB transmission needs to be considered together with PSSCH transmission. In addition, in order to meet the OCB requirements, the SL-SSB sent in 11 RBs needs to be multiplexed with PSSCH instead of being sent separately. In this way, the corresponding requirements can be met. For example, after a successful LBT, SL-SSB and PSSCH can be multiplexed in the same time slot using FDM or TDM. In this case, the overhead of SL-SSB needs to be considered to determine the number of resources for PSSCH transmission.

[0385] Fig.25 An SL-SSB suitable for use in the present disclosure is shown.

[0386] Method 1

[0387] By reflecting the actual SL-SSB overhead, the total number of REs assigned to PSSCH is determined as follows.

[0388] The number of REs N′ that the UE finally considers for each RB REThe total number of REs assigned to the PSSCH is determined by the number of scheduled RBs and the related SL SSB overhead. As shown in the above figure, the TBS for the PSSCH can be determined by excluding the resources for the S-SSB from the REs assigned to the PSSCH, which can be shown in the following equation 12.

[0389] [Equation 12]

[0390]

[0392] The TBS value is calculated by excluding the REs corresponding to SL-SSB from the total number of PSSCH REs.

[0394] Method 2

[0395] The UE needs to determine the number of REs (N′) assigned for PSSCH transmission within a single PRB. RE ).

[0397] Alt1

[0398]

[0400] Alt2

[0401]

[0403] For example, when Fig.25 As shown, when S-SSB is multiplexed with PSSCH resources, the S-SSB overhead can be considered to determine the TBS.

[0404] Fig.26 is a diagram showing a base station device and a UE device to which the present disclosure can be applied.

[0405] The base station device 2600 may include a processor 2620 , an antenna unit 2612 , a transceiver 2614 , and a memory 2616 .

[0406] The processor 2620 performs baseband-related signal processing and may include a higher layer processor 2630 and a physical layer processor 2640. The higher layer processor 2630 may process the operation of the media access control (MAC) layer, the radio resource control (RRC) layer, or a higher layer thereof. The physical layer processor 2640 may process the operation of the physical (PHY) layer (e.g., uplink received signal processing, downlink transmitted signal processing). In addition, in order to perform baseband-related signal processing, the processor 2620 may also control the operation of the base station apparatus 2600 as a whole.

[0407] The antenna unit 2612 may include one or more physical antennas, and may support multiple-input multiple-output (MIMO) transmission and reception if multiple antennas are included. In addition, beamforming may be supported.

[0408] The memory 2616 may store information processed by the processor 2620 , software, operating systems, applications, etc., related to the operation of the base station device 2600 , and may include components such as a buffer.

[0409] Processor 2620 of base station 2600 may be configured to implement operations of the base station in the examples described herein.

[0410] The UE device 2650 may include a processor 2670, an antenna unit 2662, a transceiver 2664, and a memory 2666. For example, here, the UE device 2650 may perform communication with the base station device 2600. As another example, here, the UE device 2650 may perform SL communication with another UE device. That is, the UE device 2650 used herein refers to a device capable of communicating with at least one of the base station device 2600 and other UE devices, and is not limited to communicating with a specific device.

[0411] The processor 2670 performs baseband-related signal processing and may include a higher layer processor 2680 and a physical layer processor 2690. The higher layer processor 2680 may process the operation of the MAC layer, the RRC layer, or a higher layer. The physical layer processor 2690 may process the operation of the PHY layer (e.g., downlink received signal processing, uplink transmitted signal processing). In addition, in order to perform baseband-related signal processing, the processor 2670 may also control the operation of the UE device 2650 as a whole.

[0412] Antenna unit 2662 may include one or more physical antennas and may support MIMO transmission and reception if multiple antennas are included. In addition, beamforming may be supported.

[0413] The memory 2666 may store computing processing information related to the operation of the UE device 2650 of the processor 2670 , software, operating system, applications, etc., and may include components such as a buffer.

[0415] The terminal device 2650 according to the example of the present disclosure may be associated with a vehicle. For example, the terminal device 2650 may be integrated in a vehicle, may be located in a vehicle, or may be located on a vehicle. In addition, the terminal device 2650 according to the present disclosure may be the vehicle itself. In addition, the terminal device 2650 according to the present disclosure may be at least one of a wearable terminal, an AR / VR, an Internet of Things (IoT) terminal, a robot terminal, and a public safety terminal. The terminal device 2650 to which the present disclosure may be applied may include various types of communication devices that support interactive services using side links for services such as Internet access, service execution, navigation, real-time information, autonomous driving, and safety and risk diagnosis. In addition, the terminal device 2650 may include an AR / VR device capable of performing side link operations or any type of communication device capable of performing relay operations as a sensor.

[0416] Here, the vehicle to which the present disclosure is applied may include an autonomous vehicle, a semi-autonomous vehicle, and a non-autonomous vehicle. Meanwhile, although the terminal device 2650 according to the example of the present disclosure is described in association with a vehicle, at least one of the UEs may not be associated with a vehicle. However, it is provided only as an example and should not be construed as limiting the application of the present invention.

[0417] In addition, the terminal device 2650 according to the example of the present disclosure may include various types of communication devices capable of performing collaboration to support interactive services using the side link. That is, the terminal device 2650 can directly support interactive services using the side link, and can be used as a collaborative device for supporting interactive services using the side link.

[0418] In addition, various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof. In the case of hardware implementation, the embodiments may be implemented by 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 purpose processors, controllers, microcontrollers, microprocessors, etc.

[0419] The scope of the present disclosure includes software or machine-executable instructions (e.g., OS, applications, firmware, programs, etc.) so that the operations of the methods according to various embodiments can be performed on a device or computer, and non-transitory computer-readable media that stores such software or instructions for execution on a device or computer.

[0420] Various embodiments of the present disclosure are used to explain representative aspects of the present disclosure rather than to list all possible combinations described in the various embodiments, and the contents described in the various embodiments may be applied alone or in combination of two or more embodiments.

[0421] Industrial Applicability

[0422] The above content can also be applied to other systems.

Claims

1. A method for performing sidelink communication in an unlicensed frequency band, the method comprising: Determine the entire resource element (RE) used for the physical sidelink shared channel (PSSCH); as well as A transport block size (TBS) is determined based on the entire REs.

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