Method and apparatus for sidelink communication in shared COT

Abstract

Methods and apparatus for sidelink communication in a shared COT are disclosed. The method performed by a first UE comprises the steps of: receiving a first SL transmission from a second UE; determining, on the basis of one or more conditions, whether to perform a second SL transmission in COT initiated by a second UE; and if it is determined that the second SL transmission is to be performed, performing the second SL transmission in the initiated COT.

Description

Technical Field

[0001] The present invention relates to a sidelink communication technology in an unlicensed band, and more particularly, to a sidelink communication technology in a shared channel occupancy time (COT). Background Art

[0002] Communication networks (e.g., 5G communication networks or 6G communication networks) are being developed to provide enhanced communication services compared to existing communication networks (e.g., long term evolution (LTE), LTE-Advanced (LTE-Advanced)), etc.). 5G communication networks (e.g., New Radio (NR) communication networks) can support frequency bands below 6 GHz and frequency bands above 6 GHz. In other words, 5G communication networks can support frequency region 1 (FR1) bands and / or FR2 bands. Compared with LTE communication networks, 5G communication networks can support various communication services and scenarios. For example, usage scenarios of 5G communication networks may include enhanced Mobile BroadBand (eMBB), ultra-reliable low latency communication (URLLC), massive machine type communication (mMTC), etc.

[0003] Compared to 5G communication networks, 6G communication networks can support a wide variety of communication services and scenarios. They can meet requirements for ultra-performance, ultra-bandwidth, ultra-space, ultra-precision, ultra-intelligence, and / or ultra-reliability. They can support multiple broadband frequencies and be applied to a variety of use cases, such as terrestrial communications, non-terrestrial communications, and sidelink communications.

[0004] On the other hand, in order to improve sidelink communication, carrier aggregation (CA) operation, unlicensed band operation, FR2 band operation, and / or operation for coexistence between LTE and NR may be considered. In particular, when sidelink communication is performed in an unlicensed band, a method for supporting sidelink communication may be required. For operation in an unlicensed band, a method for initiating channel occupancy time (COT), a method for sharing COT, and / or a method for sidelink communication in a shared COT may be required. Summary of the Invention

[0005] Technical issues

[0006] In order to solve the above problems, an object of the present invention is to provide a method and apparatus for sidelink communication in a shared channel occupation time (COT).

[0007] Technical Solution

[0008] A method of a first user equipment (UE) according to an embodiment of the present invention for achieving the above-mentioned purpose includes: receiving a first side link (SL) transmission from a second UE, determining whether to perform a second SL transmission in a channel occupancy time (COT) initiated by the second UE based on one or more conditions, and performing the second SL transmission in the initiated COT when it is determined to perform the second SL transmission.

[0009] When the first UE is the reception target of the first SL transmission, the second SL transmission may be performed in the initiated COT.

[0010] When the reception target of the second SL transmission is the second UE, the second SL transmission may be performed in the initiated COT.

[0011] When the second SL transmission is a physical sidelink feedback channel (PSFCH) transmission, the second SL transmission may be performed in the initiated COT.

[0012] When the second SL transmission is a sidelink synchronization signal block (S-SSB) transmission, the second SL transmission can be performed in the initiated COT.

[0013] When the first SL transmission is a signal including a COT initiation signal or COT shared information, the second SL transmission may be performed in the initiated COT.

[0014] The second SL transmission may be performed in the initiated COT when the channel access priority class (CAPC) of the second SL transmission is the same as the CAPC of the initiated COT or the CAPC of the second SL transmission has a higher priority than the CAPC of the initiated COT.

[0015] The first SL transmission may include COT sharing information, and the COT sharing information may include at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, frequency domain information of a resource block (RB) set of the COT, an additional ID, or an associated cast type.

[0016] The source ID of the second SL transmission may match the destination ID included in the COT shared information, and the destination ID of the second SL transmission may match the source ID included in the COT shared information.

[0017] The second SL transmission may be performed in the RB set indicated by the frequency domain information included in the COT shared information.

[0018] The second SL transmission may be performed based on a broadcast type indicated by an associated broadcast type included in the COT shared information, and the broadcast type is unicast, groupcast, or broadcast.

[0019] Performing the second SL transmission may include performing a type 2 SL channel access procedure in the initiated COT, and performing the second SL transmission when the type 2 SL channel access procedure is successful.

[0020] The COT initiated by the second UE may be a shared COT.

[0021] A first user equipment (UE) according to an embodiment of the present invention for achieving the above-mentioned object includes at least one processor. The at least one processor causes the first UE to receive a first sidelink (SL) transmission from a second UE, determine based on one or more conditions whether to perform a second SL transmission in a channel occupancy time (COT) initiated by the second UE, and perform the second SL transmission in the initiated COT when it is determined that the second SL transmission is to be performed.

[0022] When the first UE is the reception target of the first SL transmission, the second SL transmission may be performed in the initiated COT.

[0023] When the reception target of the second SL transmission is the second UE, the second SL transmission may be performed in the initiated COT.

[0024] When the second SL transmission is a physical sidelink feedback channel (PSFCH) transmission, the second SL transmission may be performed in the initiated COT.

[0025] When the second SL transmission is a sidelink synchronization signal block (S-SSB) transmission, the second SL transmission can be performed in the initiated COT.

[0026] The second SL transmission may be performed in the initiated COT when the channel access priority class (CAPC) of the second SL transmission is the same as the CAPC of the initiated COT or the CAPC of the second SL transmission has a higher priority than the CAPC of the initiated COT.

[0027] The first SL transmission may include COT sharing information, and the COT sharing information may include at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, frequency domain information of a resource block (RB) set of the COT, an additional ID, or an associated broadcast type.

[0028] Beneficial effects

[0029] According to the present invention, a Channel Occupancy Time (COT) initiating UE (user equipment) can transmit COT shared information to an RX-UE. The RX-UE can receive the COT shared information from the COT initiating UE and perform sidelink (SL) transmission within the shared COT based on information elements included in the COT shared information. When predefined conditions are met, the RX-UE can perform SL transmission within the shared COT. This allows for efficient SL transmission in unlicensed bands and improves communication system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a conceptual diagram showing a scenario of vehicle-to-everything (V2X) communication.

[0031] Figure 2 is a conceptual diagram illustrating a first exemplary embodiment of a communication system.

[0032] Figure 3 is a conceptual diagram illustrating an exemplary embodiment of communication nodes constituting a communication system.

[0033] Figure 4 is a block diagram illustrating an example embodiment of a communication node performing communications.

[0034] Figure 5a is a block diagram illustrating an exemplary embodiment of a transmit path.

[0035] Figure 5b is a block diagram illustrating an exemplary embodiment of a receive path.

[0036] Figure 6 is a block diagram illustrating an exemplary embodiment of a user plane protocol stack of a UE performing sidelink communications.

[0037] Figure 7 is a block diagram illustrating a first exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication.

[0038] Figure 8 is a block diagram illustrating a second exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication.

[0039] Figure 9 is a timing diagram illustrating an embodiment of a communication method in an unlicensed band.

[0040] Figure 10 is a flow chart illustrating a first embodiment of the SL-U communication method.

[0041] Figure 11 is a flow chart illustrating a second embodiment of the SL-U communication method.

[0042] Figure 12 is a flowchart illustrating a third embodiment of the SL-U communication method. DETAILED DESCRIPTION

[0043] Since the present invention is susceptible to various modifications and may have a variety of forms, specific exemplary embodiments will be shown in the drawings and described in detail in the detailed description. However, it should be understood that it is not intended to limit the present invention to specific exemplary embodiments, but on the contrary, the present invention covers all modifications and alternative forms that fall within the spirit and scope of the present invention.

[0044] Relational terms such as first, second, etc. can be used to describe various elements, but these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present invention, a first component can be named a second component, and a second component can be similarly named a first component. The term "and / or" means any one or combination of multiple related and described matters.

[0045] In the present invention, “at least one of A and B” may mean “at least one of A or B” or “at least one of a combination of one or more of A and B”. In addition, “one or more of A and B” may mean “one or more of A or B” or “one or more of a combination of one or more of A and B”.

[0046] In the present invention, "(re)transmission" may refer to "transmission", "retransmission" or "transmission and retransmission", "(re)configuration" may refer to "configuration", "reconfiguration" or "configuration and reconfiguration", "(re)connection" may refer to "connection", "reconnection" or "connection and reconnection", and "(re)access" may refer to "access", "reaccess" or "access and reaccess".

[0047] When it is mentioned that a certain component is “coupled” or “connected” to another component, it should be understood that the certain component is directly “coupled” or “connected” to the other component, or another component may be provided therebetween. Conversely, when it is mentioned that a certain component is “directly coupled” or “directly connected” to another component, it should be understood that no other component is provided therebetween.

[0048] The terms used in the present invention are only used to describe specific exemplary embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as "including" or "having" are intended to indicate the presence of features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, but it should be understood that these terms do not exclude the presence or addition of one or more features, quantities, steps, operations, components, parts, or combinations thereof.

[0049] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. Terms commonly used in dictionaries and already in dictionaries should be interpreted as having meanings that match the contextual meanings in the art. In this specification, unless explicitly defined, terms are not necessarily interpreted as having formal meanings.

[0050] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate a comprehensive understanding of the present invention, the same reference numerals refer to the same elements throughout the description of the accompanying drawings, and repeated descriptions thereof will be omitted. Operations according to the exemplary embodiments explicitly described in the present invention, as well as combinations of the exemplary embodiments, extensions of the exemplary embodiments, and / or variations of the exemplary embodiments may be performed. Some operations may be omitted, and the sequence of operations may be changed.

[0051] Even when describing a method (e.g., signal transmission or reception) performed at a first communication node among the communication nodes in the exemplary embodiment, the corresponding second communication node may also perform a method (e.g., signal reception or transmission) corresponding to the method performed at the first communication node. In other words, when describing the operation of a user equipment (UE), the corresponding base station may perform an operation corresponding to the operation of the UE. Conversely, when describing the operation of a base station, the corresponding UE may perform an operation corresponding to the operation of the base station.

[0052] A base station may be referred to by various terms, such as Node B, evolved Node B, next generation node B (gNodeB), gNB, device, apparatus, node, communication node, base transceiver station (BTS), radio remote head (RRH), transmission reception point (TRP), radio unit (RU), roadside unit (RSU), radio transceiver, access point, access node, etc. A user equipment (UE) may be referred to by various terms, such as terminal, device, apparatus, node, communication node, end node, access terminal, mobile terminal, station, subscriber station, mobile station, portable subscriber station, on-board unit (OBU), etc.

[0053] In the present invention, signaling may be one of higher layer signaling, MAC signaling, and physical (PHY) signaling, or a combination of two or more. A message used for higher layer signaling may be referred to as a "higher layer message" or a "higher layer signaling message." A message used for MAC signaling may be referred to as a "MAC message" or a "MAC signaling message." A message used for PHY signaling may be referred to as a "PHY message" or a "PHY signaling message." Higher layer signaling may refer to the operation of sending and receiving system information (e.g., a master information block (MIB), a system information block (SIB)) and / or an RRC message. MAC signaling may refer to the operation of sending and receiving a MAC control element (CE). PHY signaling may refer to the operation of sending and receiving control information (e.g., downlink control information (DCI), uplink control information (UCI), or sidelink control information (SCI)). Signaling may be signaling between a base station and a terminal and / or signaling between multiple terminals.

[0054] In the present invention, "configuration of an operation (e.g., a sending operation)" may refer to configuration information (e.g., information elements, parameters) required for the operation and / or signaling of information indicating the execution of the operation. "Configuration of information elements (e.g., parameters)" may refer to signaling of information elements. In the present invention, "signal and / or channel" may refer to a signal, a channel, or both a signal and a channel, and "signal" may be used to mean "signal and / or channel."

[0055] The communication network to which the exemplary embodiment is applied is not limited to the communication network described below, and the exemplary embodiment can be applied to various communication networks (e.g., 4G communication network, 5G communication network and / or 6G communication network). Here, "communication network" can be used interchangeably with the term "communication system".

[0056] Figure 1 This is a conceptual diagram showing a scenario of vehicle-to-everything (V2X) communication.

[0057] like Figure 1 As shown, V2X communication can include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-network (V2N) communication, etc. V2X communication can be supported by a communication system (e.g., a communication network) 140. V2X communication supported by the communication system 140 can be referred to as "cellular-V2X (C-V2X) communication." Here, the communication system 140 can include a 4G communication system (e.g., an LTE communication system or an LTE-A communication system), a 5G communication system (e.g., a NR communication system), etc.

[0058] V2V communication may include communication between a first vehicle 100 (e.g., a communication node located in the vehicle 100) and a second vehicle 110 (e.g., a communication node located in the vehicle 110). Various driving information such as speed, heading, time, location, etc. may be exchanged between the vehicle 100 and the vehicle 110 through V2V communication. For example, autonomous driving (e.g., platooning) may be supported based on the driving information exchanged through V2V communication. V2V communication supported by the communication system 140 may be performed based on a sidelink communication technology (e.g., based on Proximity Based Services (ProSe) and Device-to-Device (D2D) communication technology, etc.). In this case, communication between the vehicle 100 and the vehicle 110 may be performed using at least one sidelink channel.

[0059] V2I communication may include communication between the first vehicle 100 and an infrastructure (e.g., a roadside unit (RSU)) 120 located on the roadside. The infrastructure 120 may include a traffic light or streetlight located on the roadside. For example, when performing V2I communication, communication may be performed between a communication node located in the first vehicle 100 and a communication node located in a traffic light. Traffic information, driving information, and the like may be exchanged between the first vehicle 100 and the infrastructure 120 through V2I communication. The V2I communication supported by the communication system 140 may be performed based on a sidelink communication technology (e.g., ProSe and D2D communication technology, etc.). In this case, communication between the vehicle 100 and the infrastructure 120 may be performed using at least one sidelink channel.

[0060] V2P communication may include communication between a first vehicle 100 (e.g., a communication node located in the vehicle 100) and a person 130 (e.g., a communication node carried by the person 130). Driving information of the first vehicle 100 and movement information of the person 130, such as speed, heading, time, and location, may be exchanged between the vehicle 100 and the person 130 via V2P communication. By determining a dangerous situation based on the obtained driving information and movement information, the communication node located in the vehicle 100 or the communication node carried by the person 130 may generate an alert indicating the danger. V2P communication supported by the communication system 140 may be performed based on sidelink communication technologies (e.g., ProSe and D2D communication technologies, etc.). In this case, communication between the communication node located in the vehicle 100 and the communication node carried by the person 130 may be performed using at least one sidelink channel.

[0061] V2N communication can be communication between the first vehicle 100 (e.g., a communication node located in the vehicle 100) and the communication system (e.g., a communication network) 140. V2N communication can be performed based on 4G communication technology (e.g., LTE or LTE-A as specified by the 3GPP standard) or 5G communication technology (e.g., NR as specified by the 3GPP standard). In addition, V2N communication can be performed based on Wireless Access in Vehicular Environments (WAVE) communication technology, Wireless Local Area Network (WLAN) communication technology defined in Institute of Electrical and Electronics Engineers (IEEE) 802.11, Wireless Personal Area Network (WPAN) communication technology defined in IEEE 802.15, and the like.

[0062] On the other hand, the communication system 140 supporting V2X communication may be configured as follows.

[0063] Figure 2 is a conceptual diagram illustrating an exemplary embodiment of a communication system.

[0064] like Figure 2 As shown, the communication system may include an access network, a core network, etc. The access network may include a base station 210, a relay station 220, user equipments (UEs) 231 to 236, etc. UEs 231 to 236 may include Figure 1 The communication nodes in the vehicle 100 and the vehicle 110 are located Figure 1 The communication nodes in the infrastructure 120 are Figure 1 When the communication system supports 4G communication technology, the core network may include a serving gateway (S-GW) 250, a packet data network (PDN) gateway (P-GW) 260, a mobility management entity (MME) 270, and the like.

[0065] When the communication system supports 5G communication technology, the core network may include a user plane function (UPF) 250, a session management function (SMF) 260, an access and mobility management function (AMF) 270, etc. Alternatively, when the communication system operates in non-standalone (NSA) mode, the core network composed of the S-GW 250, the P-GW 260, and the MME 270 may support 5G communication technology as well as 4G communication technology, and the core network composed of the UPF 250, the SMF 260, and the AMF 270 may support 4G communication technology as well as 5G communication technology.

[0066] In addition, when the communication system supports network slicing technology, the core network can be divided into multiple logical network slices. For example, network slices supporting V2X communication (e.g., V2V network slices, V2I network slices, V2P network slices, V2N network slices, etc.) can be configured, and V2X communication can be supported by the V2X network slices configured in the core network.

[0067] The communication nodes (e.g., base stations, relay stations, UEs, S-GWs, P-GWs, MMEs, UPFs, SMFs, AMFs, etc.) constituting a communication system may perform communication by utilizing at least one of the following communication technologies: code division multiple access (CDMA) technology, time division multiple access (TDMA) technology, frequency division multiple access (FDMA) technology, orthogonal frequency division multiplexing (OFDM) technology, filtered OFDM technology, orthogonal frequency division multiple access (OFDMA) technology, single carrier FDMA (SC-FDMA) technology, non-orthogonal multiple access (NOMA) technology, generalized frequency division multiplexing (GFDM) technology, filter bank multi-carrier (FBMC) technology, universal filtered multi-carrier (UFMC) technology, and space division multiple access (SDMA). access, SDMA) technology.

[0068] The communication nodes (e.g., base stations, relay stations, UE, S-GW, P-GW, MME, UPF, SMF, AMF, etc.) that constitute the communication system can be configured as follows.

[0069] Figure 3 is a conceptual diagram illustrating an exemplary embodiment of communication nodes constituting a communication system.

[0070] like Figure 3 As shown, the communication node 300 may include at least one processor 310, a memory 320, and a transceiver 330 connected to a network for performing communication. In addition, the communication node 300 may further include an input interface device 340, an output interface device 350, a storage device 360, etc. Each component included in the communication node 300 can communicate with each other when connected through a bus 370.

[0071] However, each component included in the communication node 300 may be connected to the processor 310 via a separate interface or a separate bus instead of the common bus 370. For example, the processor 310 may be connected to at least one of the memory 320, the transceiver 330, the input interface device 340, the output interface device 350, and the storage device 360 via a dedicated interface.

[0072] The processor 310 can execute at least one program instruction stored in at least one of the memory 320 and the storage device 360. The processor 310 can refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the exemplary embodiment of the present invention is executed. Each of the memory 320 and the storage device 360 can include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 320 can include at least one of a read-only memory (ROM) and a random access memory (RAM).

[0073] Reference again Figure 2 In the communication system, base station 210 may form a macro cell or a small cell and may be connected to a core network via an ideal backhaul or a non-ideal backhaul. Base station 210 may transmit signals received from the core network to UEs 231 to 236 and relay station 220, and may transmit signals received from UEs 231 to 236 and relay station 220 to the core network. UE#1 231, UE#2 232, UE#4 234, UE#5 235, and UE#6 236 may belong to the cell coverage of base station 210. UE#1 231, UE#2 232, UE#4 234, UE#5 235, and UE#6 236 may connect to base station 210 by performing a connection establishment procedure with base station 210. UE#1 231 , UE#2 232 , UE#4 234 , UE#5 235 , and UE#6 236 may communicate with the base station 210 after being connected to the base station 210 .

[0074] Relay station 220 may be connected to base station 210 and may relay communications between base station 210 and UE#3 233 and UE#4 234. Specifically, relay station 220 may transmit signals received from base station 210 to UE#3 233 and UE#4 234, and may transmit signals received from UE#3 233 and UE#4 234 to base station 210. UE#4 234 may be within both the cell coverage of base station 210 and the cell coverage of relay station 220, and UE#3 233 may be within the cell coverage of relay station 220. In other words, UE#3 233 may be outside the cell coverage of base station 210. UE#3 233 and UE#4 234 may connect to relay station 220 by performing a connection establishment procedure with relay station 220. After connecting to relay station 220, UE#3 233 and UE#4 234 may communicate with relay station 220.

[0075] The base station 210 and the relay station 220 can support multiple-input multiple-output (MIMO) technology (e.g., single-user (SU)-MIMO, multi-user (MU)-MIMO, massive MIMO, etc.), coordinated multipoint (COMP) communication technology, carrier aggregation (CA) communication technology, unlicensed band communication technology (e.g., Licensed Assisted Access (LAA), enhanced LAA (eLAA), etc.), sidelink communication technology (e.g., ProSe communication technology, D2D communication technology), etc. UE#1 231, UE#2 232, UE#5 235, and UE#6 236 can perform operations corresponding to the base station 210 and operations supported by the base station 210. UE#3 233 and UE#4 234 can perform operations corresponding to the relay station 220 and operations supported by the relay station 220.

[0076] Here, the base station 210 may refer to a Node B (NB), an evolved Node B (eNB), a base transceiver station (BTS), a radio remote head (RRH), a transmit / receive point (TRP), a radio unit (RU), a roadside unit (RSU), a radio transceiver, an access point, an access node, etc. The relay station 220 may refer to a small base station, a relay node, etc. Each of the UEs 231 to 236 may refer to a terminal, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, an onboard unit (OBU), etc.

[0077] On the other hand, a communication node that performs communication in a communication network may be configured as follows. Figure 4The communication nodes shown may be Figure 3 A specific exemplary embodiment of a communication node is shown.

[0078] Figure 4 is a block diagram illustrating an example embodiment of a communication node performing communications.

[0079] like Figure 4 As shown, each of the first communication node 400a and the second communication node 400b can be a base station or a UE. The first communication node 400a can send a signal to the second communication node 400b. The transmission processor 411 included in the first communication node 400a can receive data (e.g., data units) from the data source 410. The transmission processor 411 can receive control information from the controller 416. The control information may include at least one of system information, RRC configuration information (e.g., information configured by RRC signaling), MAC control information (e.g., MAC CE), or PHY control information (e.g., DCI, SCI).

[0080] The transmit processor 411 may generate data symbols by performing processing operations on data (e.g., encoding operations, symbol mapping operations, etc.). The transmit processor 411 may generate control symbols by performing processing operations on control information (e.g., encoding operations, symbol mapping operations, etc.). In addition, the transmit processor 411 may generate synchronization / reference symbols for synchronization signals and / or reference signals.

[0081] The Tx MIMO processor 412 may perform spatial processing operations (e.g., precoding operations) on data symbols, control symbols, and / or synchronization / reference symbols. The output of the Tx MIMO processor 412 (e.g., a symbol stream) may be provided to a modulator (MOD) included in transceivers 413a to 413t. The modulator may generate modulation symbols by performing processing operations on the symbol stream and may generate signals by performing additional processing operations (e.g., analog-to-analog conversion operations, amplification operations, filtering operations, upconversion operations, etc.) on the modulation symbols. The signals generated by the modulators of transceivers 413a to 413t may be transmitted via antennas 414a to 414t.

[0082] The signal transmitted by the first communication node 400a can be received at the antenna 464a to the antenna 464r of the second communication node 400b. The signal received at the antenna 464a to the antenna 464r can be provided to the demodulator (DEMOD) included in the transceiver 463a to the transceiver 463r. The demodulator (DEMOD) can obtain samples by performing processing operations on the signal (e.g., filtering operations, amplification operations, down-conversion operations, digital conversion operations, etc.). The demodulator can perform additional processing operations on the samples to obtain symbols. The MIMO detector 462 can perform MIMO detection operations on the symbols. The receiving processor 461 can perform processing operations on the symbols (e.g., deinterleaving operations, decoding operations, etc.). The output of the receiving processor 461 can be provided to the data sink. 460 and controller 466. For example, data may be provided to data sink 460, and control information may be provided to controller 466.

[0083] On the other hand, the second communication node 400b can transmit a signal to the first communication node 400a. The transmit processor 468 included in the second communication node 400b can receive data (e.g., data units) from the data source 467 and perform processing operations on the data to generate data symbols. The transmit processor 468 can receive control information from the controller 466 and perform processing operations on the control information to generate control symbols. In addition, the transmit processor 468 can generate reference symbols by performing processing operations on reference signals.

[0084] The Tx MIMO processor 469 may perform spatial processing operations (e.g., precoding operations) on data symbols, control symbols, and / or reference symbols. The output of the Tx MIMO processor 469 (e.g., a symbol stream) may be provided to a modulator (MOD) included in transceivers 463a to 463t. The modulator may generate modulation symbols by performing processing operations on the symbol stream and may generate signals by performing additional processing operations (e.g., analog-to-analog conversion operations, amplification operations, filtering operations, and up-conversion operations) on the modulation symbols. The signals generated by the modulators of transceivers 463a to 463t may be transmitted via antennas 464a to 464t.

[0085] The signal transmitted by the second communication node 400b can be received at antennas 414a to 414r of the first communication node 400a. The signals received at antennas 414a to 414r can be provided to a demodulator (DEMOD) included in transceivers 413a to 413r. The demodulator can obtain samples by performing processing operations (e.g., filtering, amplification, down-conversion, and digital conversion) on the signal. The demodulator can perform additional processing operations on the samples to obtain symbols. The MIMO detector 420 can perform MIMO detection operations on the symbols. The receive processor 419 can perform processing operations (e.g., deinterleaving, decoding, etc.) on the symbols. The output of the receive processor 419 can be provided to the data sink 418 and the controller 416. For example, data can be provided to the data sink 418, and control information can be provided to the controller 416.

[0086] Memory 415 and memory 465 may store data, control information, and / or program codes. Scheduler 417 may perform scheduling operations for communications. Figure 4 The processors 411, 412, 419, 461, 468, and 469 and the controllers 416 and 466 shown may be Figure 3 The processor 310 shown can be used to execute the methods described in the present invention.

[0087] Figure 5a is a block diagram illustrating an exemplary embodiment of a transmit path, Figure 5b is a block diagram illustrating an exemplary embodiment of a receive path.

[0088] like Figure 5a and Figure 5b As shown, a transmission path 510 may be implemented in a communication node transmitting a signal, and a reception path 520 may be implemented in a communication node receiving a signal. The transmission path 510 may include a channel coding and modulation block 511, a serial-to-parallel (S to P) block 512, an N-point inverse fast Fourier transform (N-point IFFT) block 513, a parallel-to-serial (P to S) block 514, a cyclic prefix (CP) addition block 515, and an up-converter (UC) 516. The reception path 520 may include a down-converter (DC) 521, a CP removal block 522, an S to P block 523, an N-point FFT block 524, a P to S block 525, and a channel decoding and demodulation block 526. Here, N may be a natural number.

[0089] In the transmit path 510, information bits may be input to a channel coding and modulation block 511. The channel coding and modulation block 511 may perform encoding and decoding operations (e.g., low-density parity check (LDPC) encoding and decoding operations, polar encoding and decoding operations, etc.) and modulation operations (e.g., quadrature phase shift keying (OPSK), quadrature amplitude modulation (QAM), etc.) on the information bits. The output of the channel coding and modulation block 511 may be a modulation symbol sequence.

[0090] The S-to-P block 512 may convert the frequency-domain modulation symbols into parallel symbol streams to generate N parallel symbol streams. N may be the IFFT size or the FFT size. The N-point IFFT block 513 may generate a time-domain signal by performing an IFFT operation on the N parallel symbol streams. The P-to-S block 514 may convert the output of the N-point IFFT block 513 (e.g., the parallel signal) into a serial signal to generate a serial signal.

[0091] The CP adding block 515 may insert a CP into the signal. The UC 516 may up-convert the frequency of the output of the CP adding block 515 to a radio frequency (RF) frequency. In addition, the output of the CP adding block 515 may be filtered in baseband before up-conversion.

[0092] The signal transmitted from the transmit path 510 can be input to the receive path 520. The operations in the receive path 520 can be the inverse of the operations in the transmit path 510. The DC 521 can down-convert the frequency of the received signal to the baseband frequency. The CP removal block 522 can remove the CP from the signal. The output of the CP removal block 522 can be a serial signal. The S to P block 523 can convert the serial signal into a parallel signal. The N-point FFT block 524 can generate N parallel signals by performing an FFT algorithm. The P to S block 525 can convert the parallel signals into a sequence of modulation symbols. The channel decoding and demodulation block 526 can perform a demodulation operation on the modulation symbols and can recover the data by performing a decoding operation on the result of the demodulation operation.

[0093] exist Figure 5a and Figure 5b In the present invention, discrete Fourier transform (DFT) and inverse DFT (IDFT) can be used instead of FFT and IFFT. Figure 5a and Figure 5bEach of the blocks (eg, components) in the embodiment may be implemented by at least one of hardware, software, or firmware. For example, Figure 5a and Figure 5b Some blocks in the may be implemented by software, and other blocks may be implemented by hardware or a combination of hardware and software. Figure 5a and Figure 5b In the , a block can be subdivided into multiple blocks, multiple blocks can be integrated into one block, some blocks can be omitted, and blocks that support other functions can be added.

[0094] On the other hand, the communication between UE#5 235 and UE#6 236 may be performed based on a sidelink communication technology (e.g., ProSe communication technology, D2D communication technology). The sidelink communication may be performed based on a one-to-one scheme or a one-to-many scheme. When V2V communication is performed using the sidelink communication technology, UE#5 235 may refer to a UE located at Figure 1 The communication node in the first vehicle 100, and UE#6 236 may refer to a communication node located at Figure 1 When performing V2I communication using the sidelink communication technology, UE#5 235 may refer to a communication node located in the second vehicle 110. Figure 1 The communication node in the first vehicle 100, and UE#6236 may refer to a communication node located at Figure 1 When performing V2P communication using the sidelink communication technology, UE#5 235 may refer to a communication node located in the infrastructure 120. Figure 1 The communication node in the first vehicle 100 and UE#6 236 may refer to a communication node carried by the person 130.

[0095] The scenarios in which side link communication is applied can be classified according to the locations of the UEs (e.g., UE#5 235 and UE#6 236) participating in the side link communication, as shown in Table 1 below. For example, Figure 2 The sidelink communication scenario shown between UE#5 235 and UE#6 236 may be sidelink communication scenario #C.

[0096] [Table 1]

[0097] Sidelink communication scenario UE#5 235 location Location of UE#6 236 #A Outside the coverage of base station 210 Outside the coverage of base station 210 #B Within the coverage area of base station 210 Outside the coverage of base station 210 #C Within the coverage area of base station 210 Within the coverage area of base station 210 #D Within the coverage area of base station 210 Within the coverage area of other base stations

[0098] On the other hand, the user plane protocol stack of the UEs (eg, UE#5 235 and UE#6 236) performing sidelink communication may be configured as follows.

[0099] Figure 6 is a block diagram illustrating an exemplary embodiment of a user plane protocol stack of a UE performing sidelink communications.

[0100] like Figure 6As shown, UE#5 235 can be Figure 2 UE#5 235 is shown, and UE#6 236 may be Figure 2 UE#6 236 is shown. The sidelink communication scenario between UE#5 235 and UE#6 236 can be one of the sidelink communication scenarios #A to #D in Table 1. The user plane protocol stack of each of UE#5 235 and UE#6 236 can include a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer.

[0101] Sidelink communication between UE#5 235 and UE#6 236 may be performed using a PC5 interface (e.g., a PC5-U interface). A Layer 2 identifier (ID) (e.g., a source Layer 2 ID, a destination Layer 2 ID) may be used for sidelink communication, and the Layer 2 ID may be an ID configured for V2X communication. Furthermore, in sidelink communication, hybrid automatic repeat request (HARQ) feedback operation may be supported, and RLC acknowledged mode (AM) or RLC unacknowledged mode (UM) may be supported.

[0102] On the other hand, the control plane protocol stack of the UEs (eg, UE#5 235 and UE#6 236) performing sidelink communication may be configured as follows.

[0103] Figure 7 is a block diagram illustrating a first exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication, Figure 8 is a block diagram illustrating a second exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication.

[0104] like Figure 7 and Figure 8 As shown, UE#5 235 can be Figure 2 UE#5 235 is shown, and UE#6 236 may be Figure 2 UE#6 236 is shown. The sidelink communication scenario between UE#5 235 and UE#6 236 can be one of the sidelink communication scenarios #A to #D in Table 1. Figure 7The control plane protocol stack shown may be a control plane protocol stack for sending and receiving broadcast information (eg, Physical Sidelink Broadcast Channel (PSBCH)).

[0105] Figure 7 The control plane protocol stack shown may include a PHY layer, a MAC layer, an RLC layer, and a radio resource control (RRC) layer. Sidelink communication between UE#5 235 and UE#6 236 may be performed using a PC5 interface (eg, a PC5-C interface). Figure 8 The control plane protocol stack shown may be a control plane protocol stack for one-to-one sidelink communication. Figure 8 The control plane protocol stack shown may include a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and a PC5 signaling protocol layer.

[0106] On the other hand, channels utilized in sidelink communications between UE#5 235 and UE#6 236 may include a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), a physical sidelink discovery channel (PSDCH), a physical sidelink broadcast channel (PSBCH), and a physical sidelink feedback channel (PSFCH). The PSSCH may be used to transmit and receive sidelink data and may be configured in the UE (e.g., UE#5 235 or UE#6 236) through higher layer signaling. The PSCCH may be used to transmit and receive sidelink control information (SCI) and may also be configured in the UE (e.g., UE#5 235 or UE#6 236) through higher layer signaling.

[0107] The PSDCH may be used for the discovery process. For example, a discovery signal may be transmitted via the PSDCH. The PSBCH may be used to send and receive broadcast information (e.g., system information). In addition, a demodulation reference signal (DM-RS), synchronization signal, etc. may be utilized in the sidelink communication between UE#5 235 and UE#6 236. The synchronization signal may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS).

[0108] On the other hand, the sidelink transmission modes (TM) can be divided into sidelink TM#1 to TM#4, as shown in Table 2 below.

[0109] [Table 2]

[0110] SidelinkTM illustrate #1 Transmission using resources scheduled by the base station #2 UE automatic transmission without base station scheduling #3 Transmission using resources scheduled by base stations in V2X communications #4 UE automatic transmission without base station scheduling in V2X communication

[0111] When sidelink TM#3 or TM#4 is supported, each of UE#5 235 and UE#6 236 may perform sidelink communication using a resource pool configured by base station 210. A resource pool may be configured for each of sidelink control information and sidelink data.

[0112] The resource pool for sidelink control information can be configured based on an RRC signaling process (e.g., a dedicated RRC signaling process, a broadcast RRC signaling process). The resource pool for receiving sidelink control information can be configured through a broadcast RRC signaling process. When sidelink TM#3 is supported, the resource pool for transmitting sidelink control information can be configured through a dedicated RRC signaling process. In this case, the sidelink control information can be transmitted via resources scheduled by the base station 210 within the resource pool configured through the dedicated RRC signaling process. When sidelink TM#4 is supported, the resource pool for transmitting sidelink control information can be configured through a dedicated RRC signaling process or a broadcast RRC signaling process. In this case, the sidelink control information can be transmitted via resources automatically selected by the UE (e.g., UE#5 235 or UE#6 236) within the resource pool configured through the dedicated RRC signaling process or the broadcast RRC signaling process.

[0113] When sidelink TM#3 is supported, a resource pool for transmitting and receiving sidelink data may not be configured. In this case, sidelink data may be transmitted and received using resources scheduled by base station 210. When sidelink TM#4 is supported, a resource pool for transmitting and receiving sidelink data may be configured using a dedicated RRC signaling procedure or a broadcast RRC signaling procedure. In this case, sidelink data may be transmitted and received using resources automatically selected by a UE (e.g., UE#5 235 or UE#6 236) within a resource pool configured using a dedicated RRC signaling procedure or a broadcast RRC signaling procedure.

[0114] In the following, the side link communication method will be described. Even when describing a method performed at a first communication node in a communication node (e.g., sending or receiving a signal), the corresponding second communication node may also perform a method corresponding to the method performed at the first communication node (e.g., receiving or sending a signal). That is, when describing the operation of UE#1 (e.g., vehicle #1), the corresponding UE#2 (e.g., vehicle #2) may perform an operation corresponding to the operation of UE#1. Conversely, when describing the operation of UE#2, the corresponding UE#1 may perform an operation corresponding to the operation of UE#2. In the exemplary embodiment described below, the operation of the vehicle may be the operation of a communication node located in the vehicle.

[0115] The sidelink signal may be a synchronization signal and a reference signal used for sidelink communication. For example, the synchronization signal may be a synchronization signal / physical broadcast channel (SS / PBCH) block, a sidelink synchronization signal (SLSS), a primary sidelink synchronization signal (PSSS), a secondary sidelink synchronization signal (SSSS), etc. The reference signal may be a channel state information-reference signal (CSI-RS), a DM-RS, a phase tracking-reference signal (PT-RS), a cell specific reference signal (CRS), a sounding reference signal (SRS), a discovery reference signal (DRS), etc.

[0116] The sidelink channel may be a PSSCH, PSCCH, PSDCH, PSBCH, physical sidelink feedback channel (PSFCH), etc. In addition, the sidelink channel may refer to a sidelink channel including a sidelink signal mapped to specific resources in the corresponding sidelink channel. Sidelink communication may support broadcast services, multicast services, groupcast services, and unicast services.

[0117] The base station may transmit system information (e.g., SIB12, SIB13, SIB14) and RRC messages including configuration information for sidelink communication (i.e., sidelink configuration information) to the UE. The UE may receive the system information and RRC messages from the base station, identify the sidelink configuration information included in the system information and RRC messages, and perform sidelink communication based on the sidelink configuration information. SIB12 may include sidelink communication / discovery configuration information. SIB13 and SIB14 may include configuration information for V2X sidelink communication.

[0118] Sidelink communications can be performed within the SL bandwidth part (BWP). The base station can configure the SL BWP for the UE using higher-layer signaling. The higher-layer signaling can include SL-BWP-Config and / or SL-BWP-ConfigCommon. SL-BWP-Config can be used to configure the SL BWP for UE-specific sidelink communications. SL-BWP-ConfigCommon can be used to configure cell-specific configuration information.

[0119] In addition, the base station may configure a resource pool for the UE using higher-layer signaling. The higher-layer signaling may include SL-BWP-PoolConfig, SL-BWP-PoolConfigCommon, SL-BWP-DiscPoolConfig, and / or SL-BWP-DiscPoolConfigCommon. SL-BWP-PoolConfig may be used to configure a sidelink communication resource pool. SL-BWP-PoolConfigCommon may be used to configure a cell-specific sidelink communication resource pool. SL-BWP-DiscPoolConfig may be used to configure a resource pool dedicated to UE-specific sidelink discovery. SL-BWP-DiscPoolConfigCommon may be used to configure a resource pool dedicated to cell-specific sidelink discovery. The UE may perform sidelink communication within the resource pool configured by the base station.

[0120] Sidelink communication can support SL discontinuous reception (DRX) operation. The base station can send a higher layer message (e.g., SL-DRX-Config) including parameters related to SL DRX to the UE. The UE can perform SL DRX operation based on the SL-DRX-Config received from the base station. Sidelink communication can support inter-UE coordination operation. The base station can send a higher layer message (e.g., SL-InterUE-CoordinationConfig) including inter-UE coordination parameters to the UE. The UE can perform inter-UE coordination operation based on the SL-InterUE-CoordinationConfig received from the base station.

[0121] The side link communication can be performed based on a single SCI scheme or a multi-SCI scheme. When the single SCI scheme is used, the side link communication can be performed based on one SCI (e.g., the first phase SCI (1 st -stage SCI)) to perform data transmission (e.g., sidelink data transmission, sidelink shared channel (SL-SCH) transmission). When a multi-SCI scheme is used, two SCIs (e.g., first-stage SCI and second-stage SCI (2 nd-stage SCI)) to perform data transmission. SCI can be transmitted on PSCCH and / or PSSCH. When a single SCI scheme is utilized, SCI (e.g., first-stage SCI) can be transmitted on PSCCH. When a multi-SCI scheme is utilized, first-stage SCI can be transmitted on PSCCH, and second-stage SCI can be transmitted on PSCCH or PSSCH. The first-stage SCI can be referred to as "first-stage SCI (first-stage SCI)", and the second-stage SCI can be referred to as "second-stage SCI (second-stage SCI)". The format of the first-stage SCI may include SCI format 1-A, and the format of the second-stage SCI may include SCI format 2-A, SCI format 2-B, and SCI format 2-C.

[0122] SCI format 1-A can be used to schedule PSSCH and second-stage SCI. SCI format 1-A may include at least one of priority information, frequency resource allocation information, time resource allocation information, resource reservation period information, demodulation reference signal (DMRS) pattern information, second-stage SCI format information, beta_offset indicator, number of DMRS ports, modulation and coding scheme (MCS) information, additional MCS table indicator, PSFCH overhead indicator, or conflicting information receiver flag.

[0123] SCI format 2-A can be used for decoding PSSCH. SCI format 2-A can include the HARQ process number At least one of a new data indicator (NDI), a redundancy version (RV), a source ID, a destination ID, a HARQ feedback enable / disable indicator, a cast type indicator, or a CSI request.

[0124] SCI format 2-B may be used for decoding of PSSCH. SCI format 2-B may include at least one of a HARQ process number, NDI, RV, source ID, destination ID, HARQ feedback enable / disable indicator, zone ID, or communication range requirement.

[0125] SCI format 2-C can be used for decoding the PSSCH. In addition, SCI format 2-C can be used to provide or request inter-UE coordination information. SCI format 2-C may include at least one of a HARQ process number, NDI, RV, source ID, destination ID, HARQ feedback enable / disable indicator, CSI request, or provide / request indicator.

[0126] When the value of the provision / request indicator is set to 0, this may indicate that SCI format 2-C is used to provide inter-UE coordination information. In this case, SCI format 2-C may include at least one of a resource combination, a first resource position, a reference time slot position, a resource set type, or a lowest subchannel index.

[0127] When the value of the offer / request indicator is set to 1, this may indicate that SCI format 2-C is used to request inter-UE coordination information. In this case, SCI format 2-C may include at least one of a priority, a number of subchannels, a resource reservation period, a resource selection window position, a resource set type, or a padding bit.

[0128] On the other hand, sidelink communication can be performed in a licensed band and / or an unlicensed band. Sidelink communication performed in an unlicensed band can be referred to as sidelink-unlicensed band (SL-U) communication or unlicensed band-sidelink (U-SL) communication. In SL-U communication, the first terminal can perform communication with the second terminal according to mode 1 or mode 2. When using mode 1, the first terminal can perform communication with the second terminal based on the scheduling of the base station. When using mode 2, the first terminal can perform communication with the second terminal without the scheduling of the base station. Mode 1 can be the sidelink TM#1 or TM#3 disclosed in Table 2 above. Mode 2 can be the sidelink TM#2 or TM#4 disclosed in Table 2 above.

[0129] Figure 9 is a timing diagram illustrating an embodiment of a communication method in an unlicensed band.

[0130] refer to Figure 9, the base station may perform a listen before talk (LBT) operation to perform downlink (DL) transmission, and if the result of the LBT operation is an idle state (e.g., a clean state) of the channel, the base station may perform DL transmission. The terminal may perform an LBT operation to perform uplink (UL) transmission, and if the result of the LBT operation is an idle state of the channel, the terminal may perform UL transmission. If the result of the LBT operation is a busy state of the channel, DL transmission and / or UL transmission may not be performed. DL transmission and / or UL transmission may be performed within the channel occupancy time (COT). The COT may be initiated by the base station or the terminal. The LBT operation may be performed based on the categories disclosed in Table 3 below.

[0131] [Table 3]

[0132]

[0133] LBT operation may mean clear channel assessment (CCA) operation. The CCA operation may be performed during the CCA period. When performing the CCA operation, the communication node (e.g., a base station and / or a terminal) may check the channel state based on an energy detection (ED) method. In other words, the communication node may check whether there is another signal in the channel. If the energy detected during the CCA period is less than a threshold value (e.g., an ED threshold value), the communication node may determine that the channel state is an idle state. In other words, the communication node may determine that there are no other signals in the channel. If the channel state is an idle state, the communication node may access a channel within the COT. If the energy detected during the CCA period is greater than or equal to a threshold value, the communication node may determine that the channel state is a busy state. In other words, the communication node may determine that there is another signal in the channel. If the channel state is a busy state, the communication node will not access a channel within the COT.

[0134] In an unlicensed band, a communication node may perform an LBT operation and transmit data when the result of the LBT operation is an idle state of the channel. In this case, the base station may transmit a DL transmission burst within the COT, and the terminal may transmit an UL transmission burst within the COT. The COT may be set within the maximum COT (maximum COT, MCOT). The time slot duration of the CCA may be 5μs to 9μs. The duration of the MCOT may be 8ms. The base station may initiate and / or configure the COT based on a higher layer parameter SemiStaticChannelAccessConfig. SemiStaticChannelAccessConfig may include period information of the COT. The terminal may identify the COT initiated by the base station based on the SemiStaticChannelAccessConfig.

[0135] The terminal may initiate and / or configure COT based on a higher-layer parameter SemiStaticChannelAccessConfigUE. SemiStaticChannelAccessConfigUE may include period information and offset information of COT. The terminal may identify COT initiated by the terminal based on SemiStaticChannelAccessConfigUE.

[0136] The terminal can initiate and / or configure COT based on SemiStaticChannelAccessConfigUE in the unlicensed band. Alternatively, the base station can signal the terminal SemiStaticChannelAccessConfigSL-U of the COT for SL-U communication. The COT for SL-U communication can be called sidelink (SL)-COT. SemiStaticChannelAccessConfigSL-U may include period information and offset information of SL-COT. The terminal can configure SL-COT based on SemiStaticChannelAccessConfigSL-U. Other terminals can recognize the COT initiated based on SemiStaticChannelAccessConfigSL-U.

[0137] In an unlicensed band, a terminal may perform an LBT operation before SL communication (e.g., transmission of SL data) to enable SL communication. If the LBT operation is successful, a COT may be initiated in the unlicensed band, and SL communication may be performed within the COT. "Successful LBT operation" may mean that "the result of the LBT operation is an idle state."

[0138] In an unlicensed band, a channel access procedure may be classified into a DL channel access procedure and a UL channel access procedure. The DL channel access procedure may be classified into a Type 1 DL channel access procedure and a Type 2 DL channel access procedure. A Type 1 DL channel access procedure may be performed for initiation of a COT. A Type 2 DL channel access procedure may be performed for transmission within a COT (e.g., a shared COT). The channel access procedure may imply an LBT operation. A Type 1 DL channel access procedure may be performed for "at least one of a physical downlink shared channel (PDSCH) transmission, a physical downlink control channel (PDCCH) transmission, and an enhanced PDCCH (EPDCCH) transmission initiated by an eNB" and / or "any transmission initiated by a gNB." An eNB may mean a base station in a 4G communication system, and a gNB may mean a base station in a 5G communication system.

[0139] A Type 2 DL channel access procedure may be performed for "at least one of an eNB-initiated discovery burst transmission or a transmission not including a PDSCH" and / or "a gNB-initiated discovery burst transmission or a discovery transmission multiplexed with non-unicast information." The Type 2 DL channel access procedure may be categorized as a Type 2A DL channel access procedure, a Type 2B DL channel access procedure, and a Type 2C DL channel access procedure. The length of the sensing period (e.g., sensing interval) in each of the Type 2A DL channel access procedure, the Type 2B DL channel access procedure, and the Type 2C DL channel access procedure may differ. The length of the sensing interval in the Type 2A DL channel access procedure may be 25 μs. The length of the sensing interval in the Type 2B DL channel access procedure may be 16 μs. No sensing operation may be performed in the Type 2C DL channel access procedure.

[0140] The UL channel access procedure can be categorized as a Type 1 UL channel access procedure and a Type 2 UL channel access procedure. The Type 1 UL channel access procedure can be performed for initiating a Coordinated Transmission (COT). The Type 2 UL channel access procedure can be performed for transmissions within a Coordinated Transmission (COT) (e.g., a shared COT). The Type 1 UL channel access procedure can be performed for "at least one of a physical uplink shared channel (PUSCH) transmission or a sounding reference signal (SRS) transmission scheduled or configured by the eNB," "at least one of a PUSCH transmission or an SRS transmission scheduled or configured by the gNB," "PUCCH transmission scheduled or configured by the gNB," and / or "transmissions related to a random access (RA) procedure."

[0141] The Type 2 UL channel access procedure can be classified into a Type 2A UL channel access procedure, a Type 2B UL channel access procedure, and a Type 2C UL channel access procedure. The length of the sensing period (e.g., sensing interval) in each of the Type 2A UL channel access procedure, the Type 2B UL channel access procedure, and the Type 2C UL channel access procedure may be different. The length of the sensing period in the Type 2A UL channel access procedure may be 25 μs. The length of the sensing period in the Type 2B UL channel access procedure may be 16 μs. No sensing operation may be performed in the Type 2C UL channel access procedure.

[0142] A Type 1 DL channel access procedure, a Type 2 DL channel access procedure, a Type 1 UL channel access procedure, and / or a Type 2 UL channel access procedure may be used for SL-U communication. In this case, in the description of the Type 1 DL channel access procedure, the Type 2 DL channel access procedure, the Type 1 UL channel access procedure, and / or the Type 2 UL channel access procedure, the downlink channel and / or the uplink channel may be interpreted as a sidelink channel. The LBT operation may be interpreted as a Type 1 DL channel access procedure, a Type 2 DL channel access procedure, a new DL channel access procedure, a Type 1 UL channel access procedure, a Type 2 UL channel access procedure, and / or a new UL channel access procedure.

[0143] The UE may perform a SL channel access procedure. The SL channel access procedure may be performed to access a channel in an unlicensed frequency band. The SL channel access procedure may be classified into a type 1 SL channel access procedure and a type 2 SL channel access procedure. The type 2 SL channel access procedure may be classified into a type 2A SL channel access procedure, a type 2B SL channel access procedure, and a type 2C SL channel access procedure. The type 1 SL channel access procedure may be performed to initiate a COT. The type 2 SL channel access procedure may be performed for SL transmission within a COT (e.g., a shared COT, an initiated COT). In the type 1 SL channel access procedure, the UE may perform a random backoff operation. In the type 2 SL channel access procedure, the UE may perform a channel sensing operation. The channel sensing operation may be performed within a sensing period. In the type 2A DL channel access procedure, the length of the sensing period may be 25 μs. In the type 2B DL channel access procedure, the length of the sensing interval may be 16 μs. In the type 2C DL channel access procedure, no sensing operation may be performed.

[0144] The UE may initiate COT. COT may stand for channel occupancy (CO). The UE that initiates COT may be referred to as a COT initiating UE or an initiating UE. The signal initially sent by the COT initiating UE for initiating COT may be referred to as a COT initiating signal. The COT initiation signal may include a PSCCH, a PSSCH, a sidelink (S)-synchronization signal block (SSB) and / or a reference signal. The COT initiation signal may include COT shared information. Alternatively, the COT shared information may be sent independently of the COT initiation signal. The COT shared information (e.g., a COT initiation signal including COT shared information) may be sent to the UE via signaling. In the present invention, the signaling may be at least one of higher layer signaling (e.g., transmission of an RRC message), MAC signaling (e.g., transmission of a MAC CE), or PHY signaling (e.g., transmission of an SCI).

[0145] The COT sharing information may include a source identifier (ID) (e.g., a Layer 1 source ID), a destination ID (e.g., a Layer 1 destination ID), a channel access priority class (CAPC) (e.g., a CAPC level), a remaining COT duration, a total COT duration, a maximum COT, frequency domain information of a resource block (RB) set (e.g., an applicable RB set) for the COT, additional IDs (e.g., additional source IDs, additional destination IDs), or at least one of an associated broadcast type. The remaining COT duration and the total COT duration may each be indicated in units of time slots or milliseconds (ms). The additional IDs may include a pair of a Layer 1 source ID and a Layer 1 destination ID. The source ID (e.g., a Layer 1 source ID) may be set to the source ID of the UE initiating the COT for unicast. The source ID (e.g., a Layer 1 source ID) may be set to a reserved bit for multicast and broadcast.

[0146] The destination ID of SL transmissions performed in a COT shared by COT sharing information may match the source ID (e.g., additional source ID) included in the COT sharing information, and the source ID of SL transmissions performed in a COT shared by COT sharing information may match the destination ID (e.g., additional destination ID) included in the COT sharing information. SL transmissions in a COT shared by COT sharing information may be performed within the frequency resources (e.g., RB set) indicated by the "frequency domain information for RB set" included in the COT sharing information. SL transmissions having the same CAPC as the CAPC included in the COT sharing information may be performed in a COT shared by COT sharing information. Alternatively, SL transmissions associated with a CAPC having a higher priority than the CAPC included in the COT sharing information may be performed in a COT shared by COT sharing information. SL transmissions in a COT shared by COT sharing information may be performed based on the broadcast type (e.g., unicast, multicast, and / or broadcast) indicated by the "associated broadcast type" included in the COT sharing information.

[0147] A target RX-UE may refer to an RX-UE that is a reception target (e.g., destination) of a transmission signal (e.g., SL transmission) for a TX-UE. A non-target RX-UE may refer to an RX-UE that attempts (e.g., can attempt) to receive the transmission signal of the TX-UE in a UE other than the reception target of the transmission signal of the TX-UE. In other words, the non-target RX-UE is not a reception target of the transmission signal of the TX-UE, but can decode the transmission signal of the TX-UE.

[0148] An operating method for COT sharing in SL-U will be proposed. COT sharing can be operated based on modifications, extensions and / or combinations of the embodiments proposed in the present invention. In the present invention, the first UE can initiate a COT and send COT sharing information of the initiated COT to the second UE. The second UE can receive the COT sharing information from the first UE and check the shared COT based on the COT sharing information. The second UE can perform SL transmission based on the information elements in the COT sharing information included in the shared COT. For example, when a predefined condition is met, the second UE can determine that SL transmission is possible within the shared COT and perform SL transmission within the shared COT.

[0149] [Implementation 1] Only the target RX-UE for the COT initiating UE can use the shared COT.

[0150] Within the shared COT, the UE may receive the SL transmission of the COT-initiating UE. When receiving the SL transmission of the COT-initiating UE, the UE may perform the SL transmission after performing a type 1 SL channel access procedure or a type 2 SL channel access procedure within the shared COT. A UE that has received the SL transmission of the COT-initiating UE (e.g., a UE that performs SL transmission within the shared COT) may be restricted to be a target RX-UE for the COT-initiating UE. In other words, a target RX-UE that has successfully decoded the SL transmission of the COT-initiating UE may use the shared COT, and a non-target RX-UE that has successfully decoded the SL transmission of the COT-initiating UE may not use the shared COT. The SL transmission of the COT-initiating UE may include COT sharing information.

[0151] In the present invention, SL transmission may refer to the transmission of SL channels and / or SL signals. SL channels may be PSSCH, PSCCH, PSDCH, PSBCH, and / or PSFCH. SL signals may be S-SSBs and / or reference signals.

[0152] (Implementation Plan 1-1)

[0153] The UEs that can attempt channel access in the shared COT can be limited to the target RX-UEs that receive the COT initiation signal (or COT shared information). If the UEs that can attempt channel access in the shared COT are limited to the target RX-UEs that receive the COT initiation signal (or COT shared information), the non-target RX-UEs may not be able to perform the channel access process in the shared COT. Accordingly, the number of UEs that attempt channel access in the shared COT can be limited, and the occurrence of conflicts due to the channel access processes of multiple UEs can be reduced. In this case, the target RX-UE can successfully perform the channel access process and can stably perform SL transmission.

[0154] Figure 10 is a flow chart illustrating a first embodiment of the SL-U communication method.

[0155] refer to Figure 10 , a COT initiating UE may initiate a COT. The COT initiating UE may perform SL transmission (S1001) during the COT (e.g., COT duration). The SL transmission may be a transmission of a PSCCH and / or a PSSCH. The SL transmission may be a transmission of a COT initiating signal. The SL transmission may include COT shared information. At S1001, a reception target (e.g., a destination) of the SL transmission may be a target RX-UE. A non-target RX-UE may not be a reception target of the SL transmission.

[0156] The target RX-UE can receive SL transmission (e.g., PSCCH, PSSCH, COT initiation signal, COT shared information) from the COT initiating UE. The target RX-UE can perform SL transmission in the COT initiated by the COT initiating UE (e.g., shared COT). The non-target RX-UE can receive SL transmission (e.g., PSCCH, PSSCH, COT initiation signal, COT shared information) from the COT initiating UE. Even if the decoding of the SL transmission of the COT initiating UE is successful, the non-target RX-UE may not perform SL transmission in the COT initiated by the COT initiating UE (e.g., shared COT). In other words, the non-target RX-UE may not be allowed to perform the channel access process in the COT initiated by the COT initiating UE (e.g., shared COT).

[0157] Figure 11 is a flow chart illustrating a second embodiment of the SL-U communication method.

[0158] refer to Figure 11, the COT initiating UE can initiate COT. The COT initiating UE can perform SL transmission #1 (S1101) in the COT (e.g., COT duration). SL transmission #1 can be a transmission of PSCCH and / or PSSCH. SL transmission #1 can be a transmission of a COT initiation signal. SL transmission #1 can include COT shared information. The reception target of SL transmission #1 in S1101 can be the target RX-UE #1. The COT initiating UE can perform SL transmission #2 (S1102) in the COT (e.g., COT duration). SL transmission #2 can be a transmission of PSCCH and / or PSSCH. SL transmission #2 may not be a transmission of a COT initiation signal. The reception target of SL transmission #2 in S1102 can be the target RX-UE #2.

[0159] Target RX-UE#1 can receive SL transmission #1 and SL transmission #2. Target RX-UE#2 can receive SL transmission #1 and SL transmission #2. Since the reception target of SL transmission #1 (e.g., COT initiation signal, COT shared information) is target RX-UE#1, target RX-UE#1 can perform SL transmission in the COT initiated by the COT initiating UE (e.g., shared COT). Target RX-UE#2 is the reception target of SL transmission #2, but is not the reception target of SL transmission #1 as the COT initiation signal (or COT shared information), and target RX-UE#2 may not perform SL transmission in the COT initiated by the COT initiating UE (e.g., shared COT). In other words, target RX-UE#2 may not be allowed to perform the channel access procedure in the COT initiated by the COT initiating UE (e.g., shared COT).

[0160] exist Figure 10 and / or Figure 11 In an embodiment of the present invention, if a channel access procedure is allowed for a UE (e.g., RX-UE) in a COT (e.g., a shared COT), the UE may send a SL transmission to another UE by performing a channel access procedure in the COT (e.g., a shared COT). In other words, if Figure 10 and / or Figure 11 In an embodiment of the present invention, if a predefined condition is satisfied, the UE may perform SL transmission in a shared COT (e.g., a COT initiated by another UE). "If a target RX-UE is allowed to perform a channel access procedure in a COT initiated by a COT initiating UE (e.g., a shared COT), and the receiving target of the SL transmission for the target RX-UE is the COT initiating UE", the target RX-UE may send SL transmission to the COT initiating UE in the COT initiated by the COT initiating UE (e.g., a shared COT).

[0161] For example, in Figure 10 In an embodiment, if the reception target of the SL transmission for the target RX-UE is a COT initiating UE, the target RX-UE may be allowed to perform a channel access procedure in a COT initiated by the COT initiating UE (eg, a shared COT). Figure 11 In an embodiment, if the reception target of the SL transmission for the target RX-UE#1 is a COT initiating UE, the target RX-UE#1 may be allowed to perform a channel access procedure in a COT initiated by the COT initiating UE (e.g., a shared COT). Figure 11 In an implementation scheme, since the target RX-UE#2 is the receiving target for SL transmission #2 after the COT initiation signal (e.g., SL transmission #1), the target RX-UE#2 may not be allowed to perform the channel access process in the COT initiated by the COT initiating UE (e.g., shared COT).

[0162] (Implementation Plan 1-2)

[0163] UEs that can attempt channel access in a shared COT may be limited to target RX-UEs that receive a COT initiation signal (or COT shared information) from a COT initiating UE, and target RX-UEs that receive another signal from a COT initiating UE (e.g., an SL transmission in addition to the COT initiation signal or COT shared information). Following transmission of the COT initiation signal, the SL transmission (e.g., PSCCH and / or PSSCH) sent by the COT initiating UE may include part or all of the COT shared information. Figure 10 In the embodiments of the present invention, since the receiving target of the SL transmission (e.g., COT initiation signal, COT shared information) is the target RX-UE, according to embodiments 1-2, the target RX-UE can perform SL transmission in the COT initiated by the COT initiating UE (e.g., shared COT). According to embodiments 1-2, non-target RX-UEs may not perform SL transmission in the COT initiated by the COT initiating UE (e.g., shared COT).

[0164] exist Figure 11 In the embodiment of the present invention, the reception target of SL transmission #1 (e.g., COT initiation signal or COT sharing information) is RX-UE #1, and the reception target of SL transmission #2 is RX-UE #2. Therefore, RX-UE #1 can perform a channel access procedure in the shared COT after receiving SL transmission #1, and RX-UE #2 can perform a channel access procedure in the shared COT after receiving SL transmission #2.

[0165] If a channel access procedure is allowed for a UE in a COT (e.g., a shared COT) initiated by a COT initiating UE, the UE may send a SL transmission to another UE by performing a channel access procedure in the initiated COT (e.g., a shared COT). Figure 10 and Figure 11 In an implementation scheme, if the target RX-UE is allowed to perform a channel access procedure in a COT initiated by a COT initiating UE (e.g., a shared COT), and the receiving target of the SL transmission of the target RX-UE is the COT initiating UE", the target RX-UE can perform SL transmission by performing a channel access procedure in a COT initiated by the COT initiating UE (e.g., a shared COT).

[0166] [Implementation 2] The target RX-UE and non-target RX-UE for the COT initiating UE may use a shared COT.

[0167] A UE (e.g., RX-UE) may receive SL transmissions (e.g., PSCCH, PSSCH) from a COT-initiating UE within a shared COT. When receiving the SL transmission of the COT-initiating UE, the UE may perform a type 1 SL channel access procedure or a type 2 SL channel access procedure within the shared COT. If the type 1 SL channel access procedure or the type 2 SL channel access procedure is successful, the UE may perform SL transmission within the shared COT. The SL transmission of the COT-initiating UE signal may be a COT-initiating signal (or COT shared information). Alternatively, the SL transmission of the COT-initiating UE may be a transmission of PSCCH and / or PSSCH following the COT-initiating signal. The UE that has received the SL transmission of the COT-initiating UE may be a target RX-UE and a non-target RX-UE for the COT-initiating UE. The SL transmission of the COT-initiating UE may include COT shared information.

[0168] (Implementation Plan 2-1)

[0169] UEs that may attempt the channel access procedure in the shared COT may be limited to target RX-UEs and non-target RX-UEs that receive a COT initiation signal (or a COT sharing signal).

[0170] Figure 12 is a flowchart illustrating a third embodiment of the SL-U communication method.

[0171] refer to Figure 12, the COT initiating UE may initiate COT. The COT initiating UE may perform SL transmission #1 (S1201) in the COT (e.g., COT duration). SL transmission #1 may be a transmission of PSCCH and / or PSSCH. SL transmission #1 may be a transmission of a COT initiating signal. SL transmission #1 may include COT shared information. The reception target of SL transmission #1 in S1201 may be the target RX-UE #1. The COT initiating UE may perform SL transmission #2 (S1202) in the COT (e.g., COT duration). SL transmission #2 may be a transmission of PSCCH and / or PSSCH. SL transmission #2 may not be a transmission of a COT initiating signal. The reception target of SL transmission #2 in S1202 may be the target RX-UE #2. The non-target RX-UE may not be able to decode SL transmission #1 and successfully decode SL transmission #2.

[0172] A UE that has received (e.g., decoded) a COT initiation signal (or COT shared information) may be allowed to perform a channel access procedure in the shared COT. In this case (e.g., when the above conditions are met), target RX-UE #1 may perform a channel access procedure in the shared COT, and target RX-UE #2 and non-target RX-UEs may not perform a channel access procedure in the shared COT.

[0173] A COT (e.g., a shared COT) may include an accessible period #1 and an accessible period #2. Accessible period #1 may be the period after SL transmission #1. Accessible period #2 may be the period after SL transmission #2. A channel access procedure may be performed in the shared COT including accessible period #1 and accessible period #2.

[0174] Target RX-UE #2 may be a non-target RX-UE for SL Transmission #1, and target RX-UE #2 may successfully decode SL Transmission #1. In this case, target RX-UE #2 may perform a channel access procedure in both accessible period #1 and accessible period #2. In other words, target RX-UE #2 may be allowed to perform a channel access procedure in a shared COT that includes accessible period #1 and accessible period #2.

[0175] The non-target RX-UE may not be able to decode the COT initiation signal (or COT shared information). Therefore, the non-target RX-UE may not perform the channel access procedure in the shared COT. If the non-target RX-UE successfully decodes the COT initiation signal (or COT shared information), the non-target RX-UE may perform the channel access procedure in the shared COT.

[0176] The target RX-UE #1 may be allowed to perform a channel access procedure in a shared COT. Therefore, the target RX-UE #1 may perform SL transmission to another UE by performing a channel access procedure in the shared COT. If the receiving destination of the SL transmission for the target RX-UE #1 is a COT-initiating UE, the target RX-UE #1 may be allowed to perform a channel access procedure in a COT initiated by the COT-initiating UE (e.g., a shared COT).

[0177] (Implementation Plan 2-2)

[0178] UEs that can attempt channel access in a shared COT may be limited to target RX-UEs and non-target RX-UEs for the COT initiating UE's COT initiation signal (or COT shared information). SL transmissions by the COT initiating UE may include information for identifying the SL transmission. For example, SL transmissions by the COT initiating UE may include COT shared information. The COT shared information may include information indicating the COT initiating UE (e.g., Layer 1 ID, Layer 1 Source ID of the COT initiating UE).

[0179] exist Figure 12 In an embodiment, the target RX-UE #1 that has received the COT initiation signal (e.g., SL transmission #1) may perform a channel access procedure in the accessible period #1 and / or the accessible period #2. In other words, the target RX-UE #1 may be allowed to perform a channel access procedure in the shared COT. If the target RX-UE #2 successfully decodes the COT initiation signal (e.g., SL transmission #1), the target RX-UE #2 may perform a channel access procedure in the accessible period #1 and / or the accessible period #2.

[0180] “If the target RX-UE#2 fails to decode the COT initiation signal (eg, SL transmission #1) and receives SL transmission #2,” the target RX-UE#2 may perform a channel access procedure in the accessible period #2.

[0181] exist Figure 12 In an embodiment of the present invention, when the non-target RX-UE receives SL transmission #2 (e.g., when the non-target RX-UE successfully decodes SL transmission #2), the non-target RX-UE may perform a channel access procedure in an accessible period #2 following SL transmission #2. Figure 12 In an embodiment, when the target RX-UE#1, the target RX-UE#2, and the non-target RX-UE are allowed to perform a channel access procedure, each of the target RX-UE#1, the target RX-UE#2, and the non-target RX-UE can perform SL transmission to another UE by performing a channel access procedure in a shared COT. Figure 12In an implementation scheme, if the RX-UE is allowed to perform a channel access procedure in a COT initiated by a COT initiating UE (e.g., a shared COT), and a reception target of the SL transmission of the RX-UE is the COT initiating UE", the RX-UE can perform SL transmission by performing a channel access procedure in a COT initiated by the COT initiating UE (e.g., a shared COT).

[0182] [Embodiment 3] COT sharing information can be used to operate COT sharing operations (e.g., shared COTs).

[0183] exist Figures 10 to 12 In an embodiment, the COT shared information may be transmitted via the PSCCH and / or PSSCH. For example, the COT shared information may be included in the SCI (e.g., SCI format 1 and / or SCI format 2). The information element (e.g., the value of the information element) included in the COT shared information may vary according to the transmission timing of the PSCCH and / or PSSCH including the COT shared information. For example, the value of the remaining COT duration included in the COT shared information may vary according to the transmission timing of the COT shared information. Figure 12 In an embodiment of the present invention, the value of the remaining COT duration included in the COT sharing information included in SL transmission #2 may be set to be smaller than the value of the remaining COT duration included in the COT sharing information included in SL transmission #1. The remaining COT duration included in the COT sharing information may be set based on the actual remaining COT duration.

[0184] The COT shared information may include a modified destination ID and / or additional ID. The COT shared information may include configuration information of UEs that can perform channel access procedures in the shared COT. The UE configuration information may be indicated by additional bit indication information included in the COT shared information.

[0185] The COT sharing information may include information indicating that the UE is allowed to perform the channel access procedure within the shared COT (e.g., a 1-bit indicator), information indicating that SL transmission is allowed within the shared COT (e.g., a 1-bit indicator), and / or information indicating that the UE receives a signal to perform the channel access procedure within the shared COT (e.g., a 1-bit indicator). The indication bit (e.g., indicator) defined in Table 4 may indicate the UE that is allowed to perform the channel access procedure within the shared COT.

[0186] [Table 4]

[0187]

[0188]

[0189] The indication bit (eg, indicator) defined in Table 5 may indicate SL transmission allowed within the shared COT.

[0190] [Table 5]

[0191] Indicator bit SL transfers allowed within a shared COT 0 COT initiates SL transmission where UE is the receiving target 1 SL transfer for all receiving targets

[0192] The indication bit (eg, indicator) defined in Table 6 may indicate a signal received by the UE to perform a channel access procedure within the shared COT.

[0193] [Table 6]

[0194]

[0195] Some or all of the indicators defined in Tables 4 to 6 may be used. For example, a combination of two or more indicators defined in Tables 4 to 6 may be used. If the conditions according to Tables 4, 5, and / or 6 are met, the UE may perform SL transmission within the shared COT.

[0196] The COT shared information may include a CAPC (e.g., CAPC level, CAPC value), and the CAPC may vary depending on the transmission time of the COT shared information. UEs performing channel access procedures may be controlled based on the CAPC included in the COT shared information. A UE configured with a CAPC having the same priority as the CAPC of the shared COT (e.g., the CAPC indicated by the COT shared information) may perform SL transmission in the shared COT. Alternatively, a UE configured with a CAPC having a higher priority than the CAPC of the shared COT may perform SL transmission in the shared COT. For another example, SL transmission associated with a CAPC having the same priority as the CAPC of the shared COT (e.g., the CAPC indicated by the COT shared information) may be performed in the shared COT. Alternatively, SL transmission associated with a CAPC having a higher priority than the CAPC of the shared COT may be performed in the shared COT. The value (e.g., level) of the CAPC with the higher priority may be set to a lower value. The value (e.g., level) of the CAPC with the lower priority may be set to a higher value.

[0197] The CAPC value included in the COT shared information can be set to a value higher or lower than the previous CAPC value. The UE can perform a channel access procedure for SL transmission with the same priority as the CAPC included in the COT shared information in the shared COT. Alternatively, the UE can perform a channel access procedure for SL transmission with a higher priority than the CAPC included in the COT shared information in the shared COT. Based on the CAPC value included in the COT shared information, the UE that performs the channel access procedure in the shared COT can be controlled.

[0198] [Implementation 4] COT sharing operation (e.g., shared COT) can be operated based on S-SSB operation.

[0199] The S-SSB can be used as a COT initiation signal. The COT initiating UE can transmit the S-SSB to initiate the COT. Within the shared COT, the COT initiating UE can transmit the S-SSB. The S-SSB may include COT shared information. In this case, the PSBCH (e.g., the master information block (MIB)) included in the S-SSB may include the COT shared information.

[0200] The reception target of the S-SSB may be an unspecified UE. Therefore, the UE that can perform the channel access procedure within the shared COT may be a non-target RX-UE, rather than a target RX-UE. In other words, all UEs that have received an S-SSB (e.g., an S-SSB including COT shared information) as a COT initiation signal may perform the channel access procedure within the shared COT. If the UE (e.g., a non-target RX-UE) successfully decodes the PSBCH, it can be determined that the S-SSB including the PSBCH has been successfully received. If the UE (e.g., a non-target RX-UE) fails to decode the PSBCH, it can be determined that the reception of the S-SSB including the PSBCH has failed.

[0201] In embodiments 1 to 3, the COT initiation signal may be S-SSB. The above embodiments, modifications thereof, extensions thereof, and / or combinations thereof may be applied to S-SSB-based COT sharing operations.

[0202] The COT initiation signal may be included in the S-SSB. The COT initiation signal may be transmitted on the PSCCH and / or PSSCH. Depending on whether the COT initiation signal is an S-SSB or whether the COT initiation signal is transmitted on the PSCCH and / or PSSCH, the above embodiments, modifications thereof, extensions thereof, and / or combinations thereof may be applied.

[0203] In a shared COT, the UE may be allowed to perform a channel access procedure for sending a specific SL channel and / or a specific SL signal to a UE other than the COT initiating UE. For example, if the UE is allowed to perform a channel access procedure in the shared COT, the UE may send PSCCH, PSSCH, PSFCH and / or S-SSB to the COT initiating UE after performing the channel access procedure in the shared COT. If the UE is allowed to perform a channel access procedure in the shared COT, the UE may send a specific SL channel (e.g., PSFCH) and / or a specific SL signal (e.g., S-SSB) to a UE other than the COT initiating UE after performing the channel access procedure in the shared COT. In other words, if the SL transmission is a PSFCH transmission or an S-SSB transmission, the UE may perform SL transmission within the shared COT.

[0204] The operation of the method according to the exemplary embodiment of the present invention can be implemented as a computer-readable program or code in a computer-readable recording medium. The computer-readable recording medium may include all types of recording devices storing data that can be read by a computer system. In addition, the computer-readable recording medium can store and execute programs or codes, which can be distributed among computer systems connected via a network and read by computers in a distributed manner.

[0205] Computer readable recording media may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, or flash memory. Program instructions may include not only machine language codes created by a compiler, but also high-level language codes that can be executed by a computer using an interpreter.

[0206] Although some aspects of the present invention have been described in the context of an apparatus, these aspects can be indicated according to the corresponding description of the method, and a block or apparatus can correspond to the steps of the method or the features of the steps. Similarly, the aspects described in the context of the method can be represented as the features of the corresponding blocks or items or corresponding apparatus. Some or all steps of the method can be performed by (or using) a hardware device such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, one or more of the most important steps of the method can be performed by such an apparatus.

[0207] In some exemplary embodiments, a programmable logic device, such as a field programmable gate array, can be used to perform some or all of the functions of the methods described herein. In some exemplary embodiments, the field programmable gate array can be operated with a microprocessor to perform one of the methods described herein. Typically, the methods are preferably performed by specific hardware devices.

[0208] The description of the present invention is merely exemplary in nature, and therefore variations that do not depart from the essence of the present invention are intended to be within the scope of the present invention. Such variations should not be considered to depart from the spirit and scope of the present invention. Therefore, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope defined by the appended claims.

Claims

1. A method of a first user equipment (UE), the method comprising: receiving a first sidelink (SL) transmission from a second UE; determining whether to perform a second SL transmission in a channel occupancy time (COT) initiated by the second UE based on one or more conditions; and When it is determined to perform the second SL transmission, the second SL transmission is performed in the initiated COT.

2. The method according to claim 1, wherein In case the first UE is the reception target of the first SL transmission, the second SL transmission is performed in the initiated COT.

3. The method according to claim 1, wherein In case the reception target of the second SL transmission is the second UE, the second SL transmission is performed in the initiated COT.

4. The method according to claim 1, wherein In case the second SL transmission is a physical sidelink feedback channel (PSFCH) transmission, the second SL transmission is performed in the initiated COT.

5. The method according to claim 1, wherein In case the second SL transmission is a sidelink synchronization signal block (S-SSB) transmission, the second SL transmission is performed in the initiated COT.

6. The method according to claim 1, wherein In a case where the first SL transmission is a signal including a COT initiation signal or COT shared information, the second SL transmission is performed in the initiated COT.

7. The method according to claim 1, wherein In the case where a channel access priority class (CAPC) of the second SL transmission is the same as the CAPC of the initiated COT or the CAPC of the second SL transmission has a higher priority than the CAPC of the initiated COT, the second SL transmission is performed in the initiated COT.

8. The method according to claim 1, wherein The first SL transmission includes COT sharing information, and the COT sharing information includes at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, frequency domain information of a resource block (RB) set of the COT, an additional ID, or an associated broadcast type.

9. The method according to claim 8, wherein The source ID of the second SL transmission matches the destination ID included in the COT shared information, and the destination ID of the second SL transmission matches the source ID included in the COT shared information.

10. The method according to claim 8, wherein The second SL transmission is performed in an RB set indicated by frequency domain information included in the COT shared information.

11. The method according to claim 8, wherein The second SL transmission is performed based on a broadcast type indicated by an associated broadcast type included in the COT shared information, and the broadcast type is unicast, multicast, or broadcast.

12. The method according to claim 1, wherein Performing the second SL transfer includes: Performing a Type 2 SL channel access procedure in the initiated COT; and The second SL transmission is performed if the Type 2 SL channel access procedure is successful.

13. The method according to claim 1, wherein The COT initiated by the second UE is a shared COT.

14. A first user equipment (UE), comprising: at least one processor, The at least one processor causes the first UE to: receiving a first sidelink (SL) transmission from a second UE; determining whether to perform a second SL transmission in a channel occupancy time (COT) initiated by the second UE based on one or more conditions; and When it is determined to perform the second SL transmission, the second SL transmission is performed in the initiated COT.

15. The first UE according to claim 14, wherein: In case the first UE is the reception target of the first SL transmission, the second SL transmission is performed in the initiated COT. The first UE according to claim 14 , wherein: In case the reception target of the second SL transmission is the second UE, the second SL transmission is performed in the initiated COT.

17. The first UE according to claim 14, wherein: In case the second SL transmission is a physical sidelink feedback channel (PSFCH) transmission, the second SL transmission is performed in the initiated COT.

18. The first UE according to claim 14, wherein: In case the second SL transmission is a sidelink synchronization signal block (S-SSB) transmission, the second SL transmission is performed in the initiated COT.

19. The first UE according to claim 14, wherein: In the case where a channel access priority class (CAPC) of the second SL transmission is the same as the CAPC of the initiated COT or the CAPC of the second SL transmission has a higher priority than the CAPC of the initiated COT, the second SL transmission is performed in the initiated COT.

20. The first UE according to claim 14, wherein: The first SL transmission includes COT sharing information, and the COT sharing information includes at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, frequency domain information of a resource block (RB) set of the COT, an additional ID, or an associated broadcast type.

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