Channel access method and device in unlicensed frequency band communication

Abstract

The invention discloses a channel access method and device in unlicensed frequency band communication. The method for a first terminal comprises the steps of: receiving, from a second terminal, sharing information of COT initiated by the second terminal; determining whether SL transmission of the first terminal can be performed in the COT based on the shared information; and if the SL transmission can be performed in the COT, performing the SL transmission in the COT shared by the second terminal.

Description

Technical Field

[0001] The present disclosure relates to a channel access technology in a communication system, and more particularly, to a channel access technology in a communication system using an unlicensed frequency band. Background Art

[0002] With the advancement of information and communication technology, various wireless communication technologies are being developed. Representative wireless communication technologies may be Long Term Evolution (LTE), Advanced LTE (LTE-A), New Radio (NR), etc., which are designated as the Third Generation Partnership Project (3GPP) standards. LTE and / or LTE-A may be fourth generation (4G) communication technologies. NR may be fifth generation (5G) communication technologies.

[0003] After the commercialization of 4G communication systems (e.g., communication systems supporting LTE and / or LTE-A), 5G communication systems (e.g., communication systems supporting NR) using a higher frequency band (e.g., a frequency band of 6 GHz or more) than the frequency band of the 4G communication system (e.g., a frequency band of 6 GHz or less) are being considered to handle the surge in wireless data. The 5G communication system may support enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and / or massive machine type communication (mMTC).

[0004] The 5G communication system may support sidelink communication. In sidelink communication, communication may be performed between terminals. For example, a first terminal may transmit a signal, information, and / or data to a second terminal, and the second terminal may receive a signal, information, and / or data from the first terminal. The channel used for sidelink communication may be a physical sidelink broadcast channel (PSBCH), a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), and / or a physical sidelink feedback channel (PSFCH).

[0005] The communication system may support communication in an unlicensed band. The unlicensed band communication may require a channel access procedure. In sidelink communication between terminals, the efficiency of the communication system may be improved according to the channel access procedure of the terminal. Therefore, the channel access procedure of the terminal is required in the unlicensed band communication.

[0006] Furthermore, the above-mentioned technologies are described to enhance the understanding of the background of the present disclosure, and they may include non-prior technologies that are not known to those of ordinary skill in the art. Summary of the invention

[0007]

Technical issues

[0008] The present disclosure is intended to provide a method and apparatus for channel access in unlicensed band communications.

[0009]

Technical solution

[0010] According to an exemplary embodiment of the present disclosure for achieving the above-mentioned purpose, a method of a first terminal may include: receiving shared information of a channel occupancy time (COT) initiated by the second terminal from a second terminal; determining whether sidelink (SL) transmission of the first terminal can be performed within the COT based on the shared information; and in response to determining that SL communication can be performed within the COT, performing SL transmission within the COT shared by the second terminal.

[0011] The shared information may include at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, or frequency domain information of the COT.

[0012] COT can be initiated by a type 1 listen-before-talk (LBT) operation of the second terminal, and the SL transmission of the first terminal within the COT can be performed based on a type 2 LBT operation. The type 1 LBT operation can be performed within a variable time period, while the type 2 LBT operation can be performed within a fixed time period.

[0013] When the SL transmission is unicast SL transmission, the source of the unicast SL transmission is equal to the destination of the transmission of the second terminal, and the destination of the unicast SL transmission is equal to the source of the transmission of the second terminal, and the unicast SL transmission can be performed within the COT shared by the second terminal.

[0014] When the SL transmission is multicast SL transmission and the destination of the multicast SL transmission is equal to the destination of the transmission of the second terminal, the multicast SL transmission may be performed within the COT shared by the second terminal.

[0015] When the SL transmission is a broadcast SL transmission and a destination of the broadcast SL transmission is equal to a destination of the transmission of the second terminal, the broadcast SL transmission may be performed within the COT shared by the second terminal.

[0016] The execution of SL transmission may include: transmitting a sidelink synchronization signal block (S-SSB) within the COT.

[0017] When the SL transmission is a physical sidelink feedback channel (PSFCH) transmission and the PSFCH transmission includes a hybrid automatic repeat request (HARQ) feedback transmission for the second terminal, the PSFCH transmission may be performed within a COT shared by the second terminal.

[0018] When resources used for SL transmission belong to resources of COT, SL transmission can be performed within the COT.

[0019] According to an exemplary embodiment of the present disclosure for achieving the above-mentioned purpose, a first terminal may include: at least one processor, and the at least one processor may enable the first terminal to execute: receiving shared information of a channel occupancy time (COT) initiated by the second terminal from a second terminal; determining whether a side link (SL) transmission of the first terminal can be performed within the COT based on the shared information; and in response to determining that SL communication can be performed within the COT, performing SL transmission within the COT shared by the second terminal.

[0020] The shared information may include at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, or frequency domain information of the COT.

[0021] COT can be initiated by a type 1 listen-before-talk (LBT) operation of the second terminal, and the SL transmission of the first terminal within the COT can be performed based on a type 2 LBT operation. The type 1 LBT operation can be performed within a variable time period, while the type 2 LBT operation can be performed within a fixed time period.

[0022] When the SL transmission is unicast SL transmission, the source of the unicast SL transmission is equal to the destination of the transmission of the second terminal, and the destination of the unicast SL transmission is equal to the transmission source of the second terminal, and the unicast SL transmission can be performed within the COT shared by the second terminal.

[0023] When the SL transmission is multicast SL transmission and the destination of the multicast SL transmission is equal to the destination of the transmission of the second terminal, the multicast SL transmission may be performed within the COT shared by the second terminal.

[0024] When the SL transmission is a broadcast SL transmission and a destination of the broadcast SL transmission is equal to a destination of the transmission of the second terminal, the broadcast SL transmission may be performed within the COT shared by the second terminal.

[0025] In the execution of the SL transmission, the at least one processor may further cause the first terminal to execute: transmitting a sidelink synchronization signal block (S-SSB) within the COT.

[0026] When the SL transmission is a physical sidelink feedback channel (PSFCH) transmission and the PSFCH transmission includes a hybrid automatic repeat request (HARQ) feedback transmission for the second terminal, the PSFCH transmission may be performed within a COT shared by the second terminal.

[0027] When resources used for SL transmission belong to resources of COT, SL transmission can be performed within the COT.

[0028]

Technical Effect

[0029] According to the present disclosure, a first terminal may initiate a channel occupation time (COT) and share the COT with a second terminal. When a specific condition is met, the second terminal may perform a sidelink transmission within the COT shared by the first terminal. According to the above operation, the channel access efficiency of the terminal in unlicensed band communication may be improved. Therefore, the performance of the communication system may be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a conceptual diagram illustrating a first exemplary embodiment of a communication network.

[0031] Figure 2 is a block diagram showing a first exemplary embodiment of communication nodes constituting a communication network.

[0032] Figure 3 is a conceptual diagram illustrating a first exemplary embodiment of a system frame in a communication network.

[0033] Figure 4 is a conceptual diagram illustrating a first exemplary embodiment of a subframe in a communication network.

[0034] Figure 5 is a conceptual diagram illustrating a first exemplary embodiment of time slots in a communication network.

[0035] Figure 6 is a conceptual diagram illustrating a first exemplary embodiment of time-frequency resources in a communication network.

[0036] Figure 7 is a conceptual diagram of a first exemplary embodiment showing a configuration of a resource pool, a SL signal, and a SL channel within a SL bandwidth part (BWP).

[0037] Figure 8 is a conceptual diagram illustrating a first exemplary embodiment of an SL resource.

[0038] Fig. 9 is a sequence diagram showing a first exemplary embodiment of a communication method in an unlicensed band.

[0039] Fig.10 is a flow chart illustrating a second exemplary embodiment of a communication method in an unlicensed band.

[0040] Fig.11 is a flow chart illustrating a third exemplary embodiment of a communication method in an unlicensed band.

[0041] Fig.12 is a flow chart illustrating a fourth exemplary embodiment of a communication method in an unlicensed band. DETAILED DESCRIPTION

[0042] Although the present disclosure is capable of various modifications and alternative forms, its specific embodiments are shown in the accompanying drawings by way of example and will be described in detail herein. However, it should be understood that the present disclosure is not intended to limit the present disclosure to the specific forms disclosed, but on the contrary, the present disclosure is intended to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the present disclosure. In the entire description of the drawings, the same numbers refer to the same elements.

[0043] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, without departing from the scope of the present disclosure, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more related listed items.

[0044] In an exemplary embodiment of the present disclosure, “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”. Furthermore, in an exemplary embodiment of the present disclosure, “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”.

[0045] In exemplary embodiments of the present disclosure, "(re)transmission" may mean "transmission", "retransmission" or "transmission and retransmission", "(re)configuration" may mean "configuration", "reconfiguration" or "configuration and reconfiguration", "(re)connection" may mean "connection", "reconnection" or "connection and reconnection", and "(re)access" may mean "access", "reaccess" or "access and reaccess".

[0046] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Other words used to describe the relationship between elements should be interpreted in a similar manner (i.e., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

[0047] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "one", "an" and "the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include", "comprise", "include" and / or "comprises" specify the presence of the features, integers, steps, operations, elements and / or parts when used herein, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups.

[0048] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with the meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0049] Hereinafter, preferred exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. In order to facilitate overall understanding when describing the present disclosure, the same components in the drawings are represented by the same reference numerals, and their repeated description will be omitted.

[0050] A communication network to which an exemplary embodiment according to the present disclosure is applied will be described. The communication network to which an exemplary embodiment according to the present disclosure is applied is not limited to the content described below, and can be applied to various communication networks according to the exemplary embodiment of the present disclosure. Here, a communication network can be used in the same sense as a communication system. A communication network can refer to a wireless communication network, and a communication system can refer to a wireless communication system.

[0051] In the present disclosure, “an operation (e.g., a transmission operation) is configured” may mean “configuration information (e.g., an information element or parameter) for the operation and / or information indicating the execution of the operation is sent by a signal”. “Information elements (e.g., parameters) are configured” may mean “corresponding information elements are sent by a signal”. In the present disclosure, signaling may be at least one of system information (SI) signaling (e.g., transmission of system information blocks (SIBs) and / or master information blocks (MIBs)), RRC signaling (e.g., transmission of RRC parameters and / or higher layer parameters), MAC control element (CE) signaling, or PHY signaling (e.g., transmission of downlink control information (DCI), uplink control information (UCI), and / or sidelink control information (SCI)).

[0052] Figure 1 is a conceptual diagram illustrating a first exemplary embodiment of a communication network.

[0053] Reference Figure 1The base station 110 may support cellular communications (e.g., Long Term Evolution (LTE), Advanced LTE (LTE-A), LTE-A Pro, Unlicensed LTE (LTE-U), New Radio (NR), and Unlicensed NR (NR-U), which are specified as 3rd Generation Partnership Project (3GPP) standards), etc. The base station 110 may support Multiple Input Multiple Output (MIMO) (e.g., Single User MIMO (SU-MIMO), Multi-User MIMO (MU-MIMO), Massive MIMO, etc.), Coordinated Multi-Point (CoMP), Carrier Aggregation (CA), etc.).

[0054] The first terminal 120 and the second terminal 130 may perform sidelink communication. The sidelink communication may be performed based on mode 1 or mode 2. When mode 1 is used, the sidelink communication between the first terminal 120 and the second terminal 130 may be performed using resources allocated by the base station 110. When mode 2 is used, the sidelink communication between the first terminal 120 and the second terminal 130 may be performed using resources selected by the first terminal 120 or the second terminal 130.

[0055] The communication nodes (i.e., base stations, terminals, etc.) that constitute the above-mentioned communication network can support communication protocols based on code division multiple access (CDMA), communication protocols based on wideband CDMA (WCDMA), communication protocols based on time division multiple access (TDMA), communication protocols based on frequency division multiple access (FDMA), communication protocols based on single carrier FDMA (SC-FDMA), communication protocols based on orthogonal frequency division multiplexing (OFDM), communication protocols based on orthogonal frequency division multiple access (OFDMA), etc.

[0056] In the communication node, the base station may be referred to as Node B, evolved Node B, 5G Node B (gNodeB), base transceiver station (BTS), radio base station, radio transceiver, access point, access node, transmission / reception point (Tx / Rx Point), etc. In the communication node, the terminal may be referred to as user equipment (UE), access terminal, mobile terminal, station, user station, portable user station, mobile station, node, device, etc. The communication node may have the following structure.

[0057] Figure 2 is a block diagram showing a first exemplary embodiment of communication nodes constituting a communication network.

[0058] Reference Figure 2, the communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may also include an input interface device 240, an output interface device 250, a storage device 260, etc. Each component included in the communication node 200 can be connected through a bus 270 to communicate with each other.

[0059] However, each component included in the communication node 200 may not be connected to the common bus 270, but may be connected to the processor 210 via a separate interface or a separate bus. For example, the processor 210 may be connected to at least one of the memory 220, the transceiver 230, the input interface device 240, the output interface device 250, and the storage device 260 via a dedicated interface.

[0060] The processor 210 may execute a program stored in at least one of the memory 220 and the storage device 260. The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor, on which the method according to the embodiment of the present disclosure is executed. Each of the memory 220 and the storage device 260 may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may include at least one of a read-only memory (ROM) and a random access memory (RAM).

[0061] The following will describe the operation method of the communication node in the communication network. Even if the method to be performed at the first communication node in the communication node is described (e.g., the transmission or reception of a signal), the corresponding second communication node can perform a method corresponding to the method performed at the first communication node (e.g., the reception or transmission of a signal). That is, when describing the operation of the first terminal (e.g., the transmitting terminal), the corresponding second terminal (e.g., the receiving terminal) can perform an operation corresponding to the operation of the first terminal. Conversely, when describing the operation of the second terminal, the corresponding first terminal can perform an operation corresponding to the operation of the second terminal.

[0062] Figure 3 is a conceptual diagram illustrating a first exemplary embodiment of a system frame in a communication network.

[0063] Reference Figure 3 , time resources in a communication network may be divided into frames. For example, system frames each having a length of 10 milliseconds (ms) may be continuously configured in the time domain of the communication network. A system frame number (SFN) may be set to #0 to #1023. In this case, 1024 system frames may be repeated in the time domain of the communication network. For example, the SFN of a system frame after system frame #1023 may be set to #0.

[0064] One system frame may include two half frames, and the length of one half frame may be 5 ms. A half frame located in the starting area of ​​the system frame may be referred to as "half frame #0", and a half frame located in the ending area of ​​the system frame may be referred to as "half frame #1". The system frame may include 10 subframes, and the length of one subframe may be 1 ms. The 10 subframes in one system frame may be referred to as "subframes #0 to #9".

[0065] Figure 4 is a conceptual diagram illustrating a first exemplary embodiment of a subframe in a communication network.

[0066] Reference Figure 4 , a subframe may include n time slots, and n may be a natural number. Therefore, a subframe may include one or more time slots.

[0067] Figure 5 is a conceptual diagram illustrating a first exemplary embodiment of time slots in a communication network.

[0068] Reference Figure 5 , a time slot may include one or more symbols. Figure 5 One time slot shown may include 14 symbols. Here, the length of the time slot may vary according to the number of symbols included in the time slot and the length of the symbol. Alternatively, the length of the time slot may vary according to the parameter set. When the subcarrier spacing is 15kHz (e.g., μ=0), the length of the time slot may be 1ms. In this case, one system frame may include 10 time slots. When the subcarrier spacing is 30kHz (e.g., μ=1), the length of the time slot may be 0.5ms. In this case, one system frame may include 20 time slots.

[0069] When the subcarrier spacing is 60kHz (e.g., μ=2), the length of the time slot may be 0.25ms. In this case, one system frame may include 40 time slots. When the subcarrier spacing is 120kHz (e.g., μ=3), the length of the time slot may be 0.125ms. In this case, one system frame may include 80 time slots. When the subcarrier spacing is 240kHz (e.g., μ=4), the length of the time slot may be 0.0625ms. In this case, one system frame may include 160 time slots.

[0070] Figure 6 is a conceptual diagram illustrating a first exemplary embodiment of time-frequency resources in a communication network.

[0071] Reference Figure 6, a resource configured with one OFDM symbol in the time domain and one subcarrier in the frequency domain may be defined as a 'resource element (RE)'. A resource configured with one OFDM symbol in the time domain and K subcarriers in the frequency domain may be defined as a 'resource element group (REG)'. One REG may include K REs. REG may be used as a basic unit for resource allocation in the frequency domain. K may be a natural number. For example, K may be 12. N may be a natural number. Figure 5 The N in the time slot shown in can be 14, while Figure 6 The N in the time slot shown in can be 7. N OFDM symbols can be used as a basic unit of resource allocation in the time domain.

[0072] A method for sending and receiving data in a communication network will be described. In downlink communication, downlink data may be transmitted via a physical downlink shared channel (PDSCH). In uplink communication, uplink data may be transmitted via a physical uplink shared channel (PUSCH). In the present disclosure, PDSCH may refer to downlink data or resources for transmitting and receiving downlink data, and PUSCH may refer to uplink data or resources for transmitting and receiving uplink data. A base station may transmit downlink control information (DCI) including configuration information (e.g., resource allocation information, scheduling information) of the PDSCH on a physical downlink control channel (PDCCH). In the present disclosure, PDCCH may refer to DCI (e.g., control information) or resources for transmitting DCI.

[0073] The terminal may receive DCI on the PDCCH and identify the configuration information of the PDSCH included in the DCI. For example, the configuration information of the PDSCH may include time domain resource allocation (TDRA), frequency domain resource allocation (FDRA) and / or modulation and coding scheme (MCS) information. TDRA may indicate the resource region of the PDSCH in the time domain. FDRA may indicate the resource region of the PDSCH in the frequency domain. MCS information may indicate the MCS level or MCS index.

[0074] Sidelink (SL) communication can be performed in a communication network. SL communication can be performed in a licensed band and / or an unlicensed band. SL communication in an unlicensed band can be referred to as sidelink-unlicensed (SL-U) communication or unlicensed-sidelink (U-SL) communication. SL resources can be used for transmission of SL signals and / or channels. SL resources can be configured based on a resource pool. The resource pool can be referred to as an SL resource pool. The resource pool can include a Tx resource pool and / or an Rx resource pool. The Tx resource pool can be used for SL transmission, and the Rx resource pool can be used for SL reception. The Tx resource pool and the Rx resource pool can be distinguished from each other. The Tx resource pool and the Rx resource pool can be configured independently. In the present disclosure, SL transmission can be one of unicast SL transmission, groupcast SL transmission, multicast SL transmission, or broadcast SL transmission.

[0075] In the time domain, a resource pool may include one or more time slots, and in the frequency domain, a resource pool may include one or more subchannels. A subchannel may include N PRB Physical Resource Blocks (PRBs). PRB It can be one of 10, 12, 15, 20, 25, 50, 75 or 100. The resource pool can be configured periodically. For example, the resource pool can be configured with a periodicity of 10240 milliseconds (ms) in the time domain. Some of all time slots belonging to a period corresponding to the periodicity of 10240ms can be configured as a resource pool. According to the time division duplex (TDD) configuration, a time slot including a downlink (DL) symbol may not be configured as a resource pool. A time slot including resources that can transmit a sidelink synchronization signal block (S-SSB) may not be configured as a resource pool. A time slot that can be configured as a resource pool can be defined by a bitmap. In other words, a bitmap can indicate a time slot that can be configured as a resource pool.

[0076] The SL channel can be used to transmit and receive traffic (e.g., data), management information and / or control information (e.g., control information related to scheduling) related to SL services. The SL channel may include a physical sidelink broadcast channel (PSBCH), a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH) and / or a physical sidelink feedback channel (PSFCH). The SL signal may include a synchronization signal (e.g., a sidelink primary synchronization signal (S-PSS), a sidelink secondary synchronization signal (S-SSS)) and / or a reference signal (e.g., a demodulation reference signal (DMRS), a channel state information reference signal (CSI-RS), a phase tracking (PT)-RS, and a positioning reference signal (PRS)).

[0077] The PSSCH may be a channel for transmitting and receiving transport blocks (TBs), data, and / or traffic. The PSCCH may be a channel for transmitting and receiving control information. The PSFCH may be a channel for transmitting and receiving hybrid automatic repeat request (HARQ) feedback indicating the reception status of the PSSCH. The S-SSB may include at least one of the PSBCH, S-PSS, or S-SSS. The S-SSB may also include a DMRS. Synchronization between terminals may be performed using a synchronization signal (e.g., S-PSS and / or S-SSS).

[0078] Figure 7 is a conceptual diagram of a first exemplary embodiment showing a configuration of a resource pool, a SL signal, and a SL channel within a SL bandwidth part (BWP).

[0079] Reference Figure 7 , the resource pool may include one or more time slots in the plurality of time slots except for time slots that do not meet the configuration conditions of the resource pool and / or time slots not indicated by the bitmap. Time slots that are not continuous in the time domain may be interpreted as continuous within the resource pool. In other words, even if the time slots configured as the resource pool are not continuous, the indexes of these time slots within the resource pool may be continuous.

[0080] In the present disclosure, SL resources (e.g., SL transmission resources) may refer to resources within a resource pool. SL resources may refer to resources used for transmission of SL signals and / or SL channels. In the present disclosure, signal transmission may refer to transmitting SL signals and / or SL channels, and signal reception may refer to receiving SL signals and / or SL channels. "Signal" may be interpreted as "signal" or "signal+channel", and "channel" may be interpreted as "channel" or "channel+signal". "SL signal / channel" may be interpreted as "SL signal", "SL channel" or "SL signal+SL channel".

[0081] Figure 8 is a conceptual diagram illustrating a first exemplary embodiment of an SL resource.

[0082] Reference Figure 8, the basic transmission unit of the SL signal / channel in the time domain may be a time slot, and the basic transmission unit of the SL signal / channel in the frequency domain may be a subchannel. The transmission resources of the SL signal / channel may include one or more time slots and / or one or more subchannels. The transmission resources may include PSCCH and / or PSSCH. In addition, the transmission resources may include PSFCH. The time slots including PSFCH may be predefined (e.g., the positions of the time slots). The time slots including PSFCH may be referred to as PSFCH time slots. The configuration conditions of the PSFCH time slots in the authorized band may be different from the configuration conditions of the PSFCH time slots in the unlicensed band. The transmission operation of the HARQ feedback in the PSFCH time slots of the authorized band may be different from the transmission operation of the HARQ feedback in the PSFCH time slots of the unlicensed band. The configuration information of the SL channel actually transmitted in the transmission resource may be transmitted through signaling (e.g., RRC message, SCI). The configuration information of the SL channel may include frequency resource information (e.g., the position of the frequency resource area), time resource information (e.g., the position of the time resource area), etc.

[0083] SL resources may be allocated based on mode 1 or mode 2. Mode 1 may be referred to as resource allocation (RA)-mode 1, and mode 2 may be referred to as RA-mode 2. When RA-mode 1 is used, the base station may transmit a DCI (e.g., SL grant) including SL resource allocation information to the terminal, and the terminal may perform SL communication using the SL resources allocated by the base station. When RA-mode 2 is used, the terminal may perform a resource sensing operation within a resource pool, perform a resource selection operation on the resources sensed by the resource sensing operation, and perform SL communication using the resources selected by the resource selection operation.

[0084] In RA-mode 1, when transmission data occurs, the terminal can transmit a scheduling request (SR) for the transmission data to the base station, and the base station can allocate resources (e.g., SL resources) to the terminal based on the SR by using a dynamic grant (DG). In RA-mode 1, the base station can allocate periodic resources to the terminal in a semi-static scheme, and the terminal can perform SL communication using the periodic resources allocated by the base station.

[0085] The periodic resources allocated in a semi-static scheme may be configuration grant (CG) resources. The base station may transmit the allocation information of the CG resources to the terminal. The allocation information of the CG resources may include at least one of the location information of the CG resources, the time resource information of the CG resources, the frequency resource information of the CG resources, or the periodic information of the CG resources. According to the release process or deactivation process of the CG resources, the CG scheme can be classified into CG-type 1 and CG-type 2. In CG-type 1, the CG resources can be released through RRC signaling. In CG-type 2, the CG resources can be deactivated through DCI signaling.

[0086] In RA-mode 2, the terminal may perform a resource sensing operation during a sensing window, select a resource that satisfies a predefined condition from among the resources sensed by the resource sensing operation, and transmit an SL signal / channel using the selected resource. The resource sensing / selection method according to RA-mode 2 may be classified into a dynamic scheme and a semi-static scheme. According to the semi-static scheme, specific time resources may be occupied. The dynamic scheme and the semi-static scheme may be distinguished according to the time when new resources are selected. When using the dynamic scheme, the terminal may select resources for TB transmission each time it wants to transmit a new TB. TB transmission may include 'new TB transmission (e.g., initial TB transmission)' and / or 'TB retransmission'. One or more resources (e.g., one or more transmission resources) may be used, occupied and / or reserved for TB transmission.

[0087] When a semi-static scheme is used, the counter value of the TB transmission can be 0 during a specific time (e.g., a resource reservation interval (RRI)). Alternatively, when a semi-static scheme is used, a new transmission resource can be selected under specific conditions. The counter value of the TB transmission can be randomly selected. When a TB transmission is completed (e.g., a new TB transmission and / or a TB retransmission), the selected counter value can be reduced by 1. When a semi-static scheme is used, the terminal can continue to occupy the selected resource during a specific time. In other words, the terminal can continue to use the selected resource during a specific time. The specific time can represent the time that the terminal can exclusively occupy. The specific time can be defined as the RRI.

[0088] The base station may signal an RRI list to the terminal. The RRI list may include up to 16 RRIs (e.g., up to 16 RRI values). The signaling may be at least one of system information (SI) signaling, RRC signaling, MAC CE signaling, or PHY signaling. The terminal may receive an RRI list from the base station, select an RRI from the RRIs belonging to the RRI list, and use the selected resources (e.g., the selected transmission resources) during the selected RRI. The terminal may occupy continuous resources during the RRI. The continuous resources may be configured in a logical resource area of ​​the SL.

[0089] The first terminal may transmit an SCI including information of the selected RRI to the second terminal. The second terminal may receive the SCI from the first terminal and identify the RRI selected by the first terminal based on the information element included in the SCI. The second terminal may not select the resource during the RRI indicated by the SCI (e.g., the resource selected by the first terminal). Information about the resource selected by the first terminal may be included in the SCI.

[0090] When RA-mode 2 is used, a resource sensing window and / or a resource selection window may be configured. The resource sensing window may be referred to as a sensing window (SSW), and a resource sensing operation may be performed within the SSW. The resource selection window may be referred to as a selection window (SLW), and a resource selection operation may be performed within the SLW. The resources used during the RRI (e.g., RRI value) indicated by the SCI may be identified by the resource sensing operation performed in the SSW.

[0091] Sidelink control information (SCI) may include scheduling information (e.g., scheduling information of a TB) and / or parameters applicable to TB transmission. The parameters applied to TB transmission may be used for demodulation / decoding of the TB at a receiving terminal. SCI may be classified into first-level SCI (1 st SCI) and second level SCI (2 nd The first-level SCI may be transmitted on the PSCCH, and the second-level SCI may be transmitted on the PSSCH. The second-level SCI may be associated with the first-level SCI. The first-level SCI may include scheduling information for initial TB transmission and / or scheduling information for TB retransmission. The second-level SCI may include at least one of information about a PSSCH transmitting terminal, information about a PSSCH receiving terminal, HARQ feedback information, or retransmission information.

[0092] Y transmission resources including a time slot for transmitting a first-level SCI may be configured. Y may be a natural number. For example, Y may be 2 or 3. The first transmission resource of the Y transmission resources may be configured in a time slot for transmitting a first-level SCI. In other words, the first transmission resource of the Y transmission resources may be a time slot for transmitting a first-level SCI. The time slot in which (Y-1) transmission resources are configured may be defined by a time slot offset. The time slot offset may be a positive integer. The maximum value of the time slot offset may be 32.

[0093] The first transmission resource scheduled may include N in the frequency domain. subchannel sub-channels. subchannel The first subchannel (eg, the starting subchannel) of the N subchannels may be a subchannel for transmitting the first-level SCI. subchannel Can be a natural number. N subchannel The first-level SCI may include frequency resource information of the second transmission resource (e.g., information of N subchannels, information about the starting subchannel in the N subchannels) and / or frequency resource information of the third transmission resource (e.g., information of N subchannels, information about the starting subchannel in the N subchannels). The number of subchannels N of the second transmission resource may be equal to or less than the number of subchannels N of the first transmission resource. subchannelThe number of subchannels N of the third transmission resource may be the same as the number of subchannels N of the first transmission resource. subchannel The first transmission resource among the Y transmission resources may be a transmission resource for the first TB transmission (eg, initial TB transmission). The remaining (Y-1) transmission resources may be transmission resources for TB retransmission.

[0094] The first level SCI may include one or more information elements defined in Table 1 below.

[0095] [Table 1]

[0096]

[0097]

[0098] The second level 2 SCI may include one or more information elements. The information elements included in the second level SCI may vary according to the format of the second level SCI. The second level SCI may include one or more information elements defined in Table 2 below.

[0099] [Table 2]

[0100] Information Elements HARQ process number New Data Indicator (NDI) Redundancy Version (RV) Source ID Destination ID HARQ feedback enable / disable indicator Broadcast Type Indicator Other information elements

[0101] PSFCH can be periodically configured within the SL resource area. The time slot in which PSFCH is configured can be called PSFCH time slot. PSFCH time slot can be configured according to periodicity. The periodicity of PSFCH time slot can be called PSFCH transmission timing resource (TPR). PSFCH TPR can be defined on a time slot basis within the resource pool. PSFCH TPR can be 1 time slot, 2 time slots or 4 time slots. PRBs in which PSFCH can be transmitted in the frequency domain can be indicated by a bitmap. PRBs that can be used for PSFCH transmission can be all PRBs or some PRBs. One PSFCH can be transmitted in one PRB. Alternatively, in an unlicensed band, one PSFCH can be transmitted in one or more PRBs.

[0102] The PRB for transmitting the PSFCH may be determined based on the position of the time slot in which the PSSCH associated with the PSFCH is received. The difference (e.g., time slot offset, interval) between the time slot in which the PSSCH is received and the time slot in which the PSFCH is to be transmitted may be considered. For example, the PSFCH may be transmitted in the PSFCH time slot that first occurs after K time slots from the time slot n in which the PSSCH is received. The PRB for transmitting the PSFCH may be determined based on the function f(P PSFCH ,n,K,k subch ) is used to define the PRB index (e.g., the index of the PRB transmitting the PSFCH). PSFCHmay be the periodicity of the PSFCH. n may be the index of the time slot in which the PSSCH is received. K may be the time slot offset used to determine the PSFCH time slot in which the PSFCH is transmitted. k subch It can be the index of the subchannel in which the PSCCH is configured.

[0103] In the function f(.) for determining the PRB index, at least one of different codes q, an identifier (ID) of a transmitting terminal, or an ID of a receiving terminal transmitting the PSFCH may be considered. The code q may be defined by a cyclic shift or a cyclic shift pair. The cyclic shift may be associated with different Zadoff-Chu sequences. A cyclic shift pair may refer to a pair of different sequences according to an acknowledgement (ACK) or a negative ACK (NACK).

[0104] A set of PRBs for transmitting the PSFCH may be determined based on the index of the time slot #n in which the PSSCH is transmitted and / or the subchannel in which the PSSCH is transmitted. The code conveyed by the PSFCH and the PRBs in the PRB set may be determined based on a function that considers at least one of the ID of the transmitting terminal or the ID of the receiving terminal that transmits the PSFCH.

[0105] The base station may transmit configuration information (e.g., transmission resource information) of the SL channel to the terminal. The terminal may receive the configuration information of the SL channel from the base station, and transmit the SL channel based on the configuration information (e.g., the transmission resource indicated by the configuration information). Alternatively, the terminal may select a resource by performing a resource sensing operation and / or a resource selection operation, and may transmit the SL channel in the selected resource. The selected resource may refer to a transmission resource. The transmission resource may include one or more subchannels and one or more time slots.

[0106] The transmitting terminal may transmit SCI including transmission resource information (e.g., scheduling information) of the PSSCH to the receiving terminal. The transmission resource information may be allocation information of subchannels and / or time slots of the PSSCH. The transmitting terminal may refer to a terminal that transmits the PSSCH (e.g., data). The receiving terminal may refer to a terminal that receives the PSSCH (e.g., data). The transmission resource information included in the SCI may indicate the transmission resources of the PSSCH in the time slot in which the SCI is transmitted. Alternatively, the transmission resource information included in the SCI may indicate the transmission resources of the PSSCH in a time slot other than the time slot in which the SCI is transmitted.

[0107] In SL-U communication, a listen-before-talk (LBT) operation can be performed to coexist with other communication nodes (e.g., communication devices). The actual transmission resources can be determined based on the result of the LBT operation. The terminal can perform an LBT operation, and when the LBT operation is successful, the terminal can use the channel within a specific time (e.g., channel occupancy time (COT)). For example, when the LBT operation of the terminal is successful, the terminal can initiate a COT, and the terminal can perform communication (e.g., SL-U communication) during the COT. Depending on specific conditions, other terminals (e.g., terminals that do not initiate COT) can perform communication (e.g., SL-U communication) during the COT. In other words, the COT can be shared with other terminals, and in this case, other terminals can perform communication within the shared COT.

[0108] The transmission unit (e.g., symbol configuration) within the COT may vary. Configuration information of the transmission unit within the COT may be transmitted via signaling (e.g., SCI). A symbol may refer to an OFDM symbol. Figure 8 In an exemplary embodiment of the present invention, the PSCCH and the PSSCH may be configured together in the transmission resource. The PSCCH may be configured starting from the PRB with the lowest index in the subchannel with the lowest index in the subchannel configured for PSSCH transmission.

[0109] The operation, process, control information and / or configuration information of the working channel occupation in SL-U communication will be described. The working channel may refer to a frequency resource with a bandwidth of a predefined size. The resources of the unlicensed frequency band (e.g., time resources, frequency resources, carriers, subcarriers, subchannels) may be occupied by communication nodes belonging to a network other than a cellular network (e.g., a 4G network, a 5G network) (e.g., a wireless local area network (WLAN)). The resources of the unlicensed frequency band may be occupied by signals / channels transmitted and received between base stations and terminals belonging to the cellular network. The resources of the unlicensed frequency band may be occupied by signals / channels transmitted and received between terminals belonging to the cellular network.

[0110] In the present disclosure, a communication node (e.g., a base station, a terminal) transmitting a signal / channel may be represented as a transmitting node, and a communication node (e.g., a base station, a terminal) receiving a signal / channel may be represented as a receiving node. In an unlicensed band, a communication node may share a working channel. An LBT operation may be performed to minimize interference between communication nodes. An LBT operation may include an operation of identifying whether a working channel is occupied by another signal before transmitting a signal / channel. When supporting an LBT operation, a communication node (e.g., a transmitting node) may perform a random backoff procedure.

[0111] When the LBT operation is successful, the communication node may occupy the working channel. The occupation of the working channel may be referred to as channel occupation (CO). The terminal may ensure the CO by performing the LBT operation. The configuration of the CO may vary according to the type of LBT operation performed by the terminal. For example, the maximum length of the CO may vary according to the type of LBT operation performed by the terminal. The type of LBT operation performed by the terminal may vary according to the priority class of the data to be transmitted by the terminal in the CO. The priority class may be a channel access priority class (CAPC).

[0112] The terminal may perform an LBT operation using different parameters (e.g., different LBT parameters) to obtain a CO corresponding to each priority class. When performing an LBT operation according to a priority class, the parameter determining the execution time of the LBT operation may vary. In an LBT operation involving a random backoff procedure, the minimum and / or maximum size of a contention window (CW) may be set differently for each priority class. The terminal may select a random backoff counter within a CW and perform a random backoff procedure based on the selected random backoff counter.

[0113] The fixed time period for performing the LBT operation may be determined based on the type of the LBT operation and / or the LBT parameters. The length of the fixed time period may be 16 μs or 25 μs. A communication node (e.g., a transmitting node) that has performed the LBT operation may transmit information about the CO (e.g., CO configuration information) obtained through the LBT operation to another communication node (e.g., a receiving node). The CO configuration information may include LBT parameters for the LBT operation of the terminal. The LBT parameters may include information on priority categories. The CO configuration information may include at least one of information on the start time of the CO, information on the length of the CO, or information on the end time of the CO. In the present disclosure, "time point" may be interpreted as "time".

[0114] The receiving node may receive CO configuration information from the transmitting node, and identify LBT parameters for obtaining the CO based on the CO configuration information. The receiving node may identify the priority category of the CO initiated by the transmitting node based on the LBT parameters. The receiving node may identify the CO initiated by the transmitting node based on the CO configuration information, and perform communication within the CO. For example, the receiving node may transmit and receive signals / channels within the CO.

[0115] The transmitting node may configure the channel occupation time (COT). The configuration of COT means the initiation of COT. COT may be configured in time resources and / or frequency resources. COT may be configured in one or more resource blocks (RBs) or one or more RB sets. The configuration information of COT (i.e., COT configuration information) may indicate the time resources and / or frequency resources for configuring COT. The frequency resources of COT may include one or more RBs or one or more RB sets. COT may be referred to as CO or channel occupation resources (COR). In an unlicensed band, resources may be shared by multiple communication nodes. Communication nodes may use non-continuous resources (e.g., non-continuous time resources and / or non-continuous frequency resources). In this case, signal / channel transmission in the unlicensed band may be performed in a discontinuous burst scheme. A burst scheme may refer to a transmission performed in a transmission resource including one or more time slots.

[0116] The signal / channel may be transmitted in a time shorter than a time slot. The time shorter than a time slot may include continuous symbols. The time shorter than a time slot may be a micro-slot. Continuous transmission resources may be configured within the COT. The transmitting node may transmit an initial signal and / or a burst signal (e.g., PSSCH, PSFCH, PSCCH, reference signal) within the COT. The initial signal may be a signal obtained by copying the signal of the first symbol of the SL transmission. Alternatively, the initial signal may be a signal including a cyclic prefix (CP).

[0117] In SL-U communication, the terminal may perform an LBT operation before transmitting a signal / channel. If the result of the LBT operation indicates an idle state, the terminal may transmit a signal / channel. If the result of the LBT operation indicates a busy state, the terminal may not transmit a signal / channel. "The result of the LBT operation indicates an idle state" may mean "the LBT operation is successful". "The result of the LBT operation indicates a busy state" may mean "the LBT operation fails". Based on the comparison result between the energy detection level and a predefined threshold, the result of the LBT operation may be determined to indicate an idle state or a busy state.

[0118] LBT operation can be classified into type 1 LBT operation and type 2 LBT operation. In type 1 LBT operation, the channel sensing time may be variable. In other words, type 1 LBT operation may be performed within a variable time period. The channel sensing time may be changed by a random variable. Type 1 LBT operation may refer to an LBT operation involving a random backoff procedure. In type 2 LBT operation, the channel sensing time may be fixed. In other words, type 2 LBT operation may be performed within a fixed time period. The channel sensing time may be mμs. m may be a natural number.

[0119] When performing type 1 LBT operation, the terminal may randomly select a value N according to a uniform probability within a CW. The value N may be an integer. The value N may be a random backoff counter. The terminal may perform a channel sensing operation within a predefined sensing period (e.g., a sensing time slot period). The channel sensing operation may represent an energy detection operation for time and / or frequency resources. If the result of the channel sensing operation within one sensing period indicates an idle state, the terminal may reduce the value N selected within the CW by 1. If the result of the channel sensing operation within one sensing period indicates a busy state, the terminal may perform a channel sensing operation in addition. If the results of the channel sensing operations within N sensing periods indicate an idle state, the terminal may transmit a signal / channel.

[0120] The terminal may perform a channel access procedure to use an unlicensed band. The channel access procedure may be an LBT operation. The terminal may obtain COT by performing a channel access procedure. In other words, when the channel access procedure of the terminal is successful, the terminal may initiate COT. In the present disclosure, "the terminal obtains COT" may mean "the terminal initiates COT" and / or "the terminal configures COT". The terminal may perform an LBT operation (e.g., a type 1 LBT operation) to obtain COT. When the type 1 LBT operation is successful, the terminal may obtain COT. The terminal may obtain COT by performing a semi-static channel access procedure.

[0121] The LBT operation (e.g., the type of LBT operation) performed by the terminal for signal / channel transmission within the COT may be different from the LBT operation (e.g., the type of LBT operation) performed by the terminal for signal / channel transmission outside the COT. The terminal may perform a type 2 LBT operation for signal / channel transmission within the COT. The type 2 LBT operation may be performed within a fixed time period. The terminal may perform a type 1 LBT operation for signal / channel transmission outside the COT. The type 1 LBT operation may be performed within a variable time period.

[0122] The terminal may share the obtained COT or the initiated COT with other terminals. This operation may be a COT sharing operation. In the present disclosure, a terminal that shares the obtained COT or the initiated COT with another terminal may be referred to as "terminal A", and a terminal that shares the COT obtained or initiated by another terminal may be referred to as "terminal B". In addition, terminal A may be referred to as a first terminal or a second terminal, and terminal B may be referred to as a second terminal or a first terminal.

[0123] Terminal A can perform LBT operation using different LBT parameters according to the priority class of the data. LBT parameters (e.g., contention window, length of sensing period (e.g., sensing window)) for LBT operation can vary according to the priority class. The priority class can be selected by terminal A. The maximum length of COT can vary depending on the result of the LBT operation according to the priority class. The priority class can refer to a channel access priority class (CAPC).

[0124] Terminal A can obtain COT according to the result of the LBT operation. If the LBT operation is successful, terminal A can obtain COT. If the LBT operation fails, terminal A cannot obtain COT. Terminal A can perform signal / channel transmission within the COT. The transmission of terminal A within the COT can be SL transmission or UL transmission. Terminal A can transmit information about the obtained COT (e.g., COT configuration information, COT sharing information) to terminal B. The COT configuration information and the COT sharing information can be the same information. The COT configuration information can be CO configuration information, and the COT sharing information can be CO sharing information. Terminal B can receive information about the COT initiated by terminal A from terminal A, and transmit a signal / channel within the COT initiated by terminal A.

[0125] Fig. 9 is a sequence diagram showing a first exemplary embodiment of a communication method in an unlicensed band.

[0126] Reference Fig. 9 , terminal A can obtain COT (S910). For example, terminal A can obtain COT by performing an LBT operation (e.g., type 1 LBT operation). Terminal A can transmit information about the obtained COT (e.g., COT configuration information, COT sharing information) to terminal B (S920). COT configuration information (e.g., COT sharing information) can be transmitted via MAC CE and / or SCI. In other words, terminal A can transmit a MAC CE including COT configuration information to terminal B. MAC CE can be transmitted on a PSSCH scheduled by SCI. Alternatively, terminal A can transmit an SCI including COT configuration information to terminal B. The COT configuration information may include one or more information elements defined in Table 3 below.

[0127] [Table 3]

[0128] Information Elements Source Identifier (ID) Destination ID CAPC (e.g., priority category) Remaining CO duration Frequency domain information of CO Additional IDs (e.g., additional source IDs and / or additional destination IDs) Additional time domain information of CO Additional frequency domain information of CO Shared indicators Shared offset Shared target information

[0129] The source ID may be a source ID transmitted within the COT for terminal A (e.g., the ID or address of terminal A). The destination ID may be a destination ID transmitted within the COT for terminal A (e.g., the ID of a specific terminal (e.g., the ID or address of terminal B), a multicast ID, a broadcast ID). The multicast ID may be a multicast address, and the broadcast ID may be a broadcast address.

[0130] CAPC may be a CAPC transmitted within the COT for terminal A. The frequency domain information may be frequency resource information (e.g., frequency resource allocation), and the time domain information may be time resource information (e.g., time resource allocation). A sharing indicator (e.g., COT sharing indicator, CO sharing indicator) may indicate whether the COT initiated by terminal A is shared. The sharing offset may be an offset from the transmission time (e.g., reception time) of the COT configuration information to the start time when the shared COT is available. The sharing offset may be set in units of time slots.

[0131] Terminal B may receive COT configuration information from terminal A. Terminal B may identify information elements included in the COT configuration information (S930). Terminal B may identify the COT initiated by terminal A based on the COT configuration information. Terminal B may identify whether the COT is available (S940). If the COT initiated by terminal A is available, terminal B may transmit a signal / channel within the COT (S950). When terminal A indicates COT sharing and / or when terminal B can perform communication within the remaining CO duration (e.g., the remaining COT duration), terminal B may determine that the COT initiated by terminal A is available.

[0132] The remaining CO duration may indicate a period from the time when the terminal A transmits the COT configuration information including the information about the remaining CO duration to the end time of the COT (e.g., the COT associated with the COT configuration information). The remaining CO duration may be indicated in units of time slots. For example, when the COT configuration information is transmitted in time slot #NM, and the COT associated with the COT configuration information ends in time slot #N, the terminal A may notify the terminal B of the remaining CO duration corresponding to the M time slots. Alternatively, the terminal A may notify the terminal B of the remaining CO duration corresponding to at least one of the M-1, M, or M+1 time slots. The terminal B may receive the information about the remaining CO duration from the terminal A, and may identify the end time of the COT based on the remaining CO duration. The terminal B may identify the period from the reception time of the COT setting information including the CO duration information to the end time of the COT associated with the COT configuration information based on the remaining CO duration. The terminal B may identify the length of the remaining period within the COT initiated by the terminal A based on the remaining CO duration.

[0133] If the period required for signal / channel transmission of terminal B belongs to the remaining CO duration (e.g., the remaining period within the COT), terminal B may transmit the signal / channel within the COT shared by terminal A. If the period required for signal / channel transmission of terminal B is longer than the remaining CO duration (e.g., the remaining period within the COT), terminal B may not transmit the signal / channel within the COT shared by terminal A. In this case, terminal B may obtain a separate COT and transmit the signal / channel within the obtained COT.

[0134] The COT configuration information transmitted by terminal A may include information about the sharing offset. The sharing offset may be an offset from the transmission time (e.g., reception time) of the COT configuration information to the start time when the shared COT is available. The sharing offset may be set in units of time slots. Terminal B may receive the COT configuration information from terminal A and identify the sharing offset included in the COT configuration information. Terminal B may determine the start time when the COT shared by terminal A is available based on the sharing offset. Terminal B may determine the available period of the shared COT based on the start time when the shared COT is available.

[0135] If the period required for signal / channel transmission of terminal B belongs to the available period of the shared COT, terminal B may transmit the signal / channel in the COT shared by terminal A. If the period required for signal / channel transmission of terminal B is longer than the available period of the shared COT, terminal B may not transmit the signal / channel in the COT shared by terminal A. In this case, terminal B may obtain a separate COT and transmit the signal / channel in the obtained COT.

[0136] The COT configuration information transmitted by terminal A may include frequency domain information (e.g., frequency domain information of COT). The frequency domain information of COT may indicate the frequency resource (e.g., frequency region) of the signal / channel of terminal A. The COT configuration information including frequency domain information may be transmitted by the frequency resource of the signal / channel of terminal A. Terminal B may receive the COT configuration information from terminal A and identify the frequency domain information included in the COT configuration information. Terminal B may identify the frequency resource of the COT shared by terminal A based on the frequency domain information.

[0137] If the frequency resources required for signal / channel transmission of terminal B belong to the frequency resources of the shared COT, terminal B can transmit the signal / channel in the COT shared by terminal A. If the frequency resources required for signal / channel transmission of terminal B are greater than the frequency resources of the shared COT, terminal B may not transmit the signal / channel in the COT shared by terminal A. In this case, terminal B may obtain a separate COT and transmit the signal / channel in the obtained COT.

[0138] The COT configuration information transmitted by terminal A may include information about a priority class (e.g., CAPC). The information about the priority class may be an index indicating the priority class. Terminal B may receive the COT configuration information from terminal A and identify the information about the priority class included in the COT configuration information. Terminal B may identify the priority class of a COT (e.g., a COT shared by terminal A) based on the information about the priority class. The priority class of a COT may be the CAPC of the COT. Terminal B may determine the priority class of data that may be transmitted within the COT based on the priority class of the COT.

[0139] When the priority class of the signal / channel (e.g., data) of terminal B is the same as the priority class indicated by the COT configuration information, or when the priority class of the signal / channel (e.g., data) of terminal B is higher than the priority class indicated by the COT configuration information, terminal B may transmit the signal / channel within the COT shared by terminal A. Alternatively, when the priority class of the signal / channel (e.g., data) of terminal B is the same as the priority class indicated by the COT configuration information, or when the priority class of the signal / channel (e.g., data) of terminal B is lower than the priority class indicated by the COT configuration information, terminal B may transmit the signal / channel within the COT shared with terminal A.

[0140] When the priority class of the signal / channel (e.g., data) to be transmitted by terminal B satisfies the condition of the priority class of the COT (e.g., the COT shared by terminal A), terminal B may transmit the signal / channel within the COT. When the priority class of the signal / channel (e.g., data) to be transmitted by terminal B does not satisfy the condition of the priority class of the COT (e.g., the COT shared by terminal A), terminal B may not transmit the signal / channel within the COT. In this case, terminal B may obtain a separate COT and transmit the signal / channel within the obtained COT.

[0141] The COT configuration information transmitted by terminal A may include information about a shared target. The information about the shared target may indicate a target (e.g., a terminal) with which the COT is shared. The information about the shared target may include information about the location of the terminal that can share the COT. For example, the information about the shared target may include information about the location of terminal A. Terminals located around terminal A may share the COT initiated by terminal A. The information about the shared target may include information about the communication distance requirement of terminal A. The information about the communication distance requirement may indicate the coverage of terminal A. The information about the shared target may include at least one of information about the location of terminal A or information about the communication distance requirement of terminal A.

[0142] Terminal B may receive COT configuration information from terminal A, and identify information about a shared target included in the COT configuration information. Terminal B may identify the coverage of terminal A based on the information about the shared target. If terminal B is within the coverage of terminal A, terminal B may transmit a signal / channel within the COT shared by terminal A. In other words, the COT initiated by terminal A may be shared with terminal B. If terminal B is not within the coverage of terminal A, terminal B may not transmit a signal / channel within the COT shared by terminal A. In other words, the COT initiated by terminal A may not be shared with terminal B.

[0143] The COT initiated by terminal A may be shared with terminal B, and terminal B may perform communication using the COT. Terminal B may transmit a signal / channel to terminal A within the COT shared by terminal A. In other words, the destination of the signal / channel transmitted by terminal B within the COT shared by terminal A may include terminal A. Terminal B may not transmit a signal / channel to a terminal other than terminal A within the COT shared by terminal A. In other words, within the COT shared by terminal A, signal / channel transmission to a destination other than the destination including terminal A may not be performed.

[0144] The information about the sharing target included in the COT configuration information may include information about the terminal that can share the COT initiated by terminal A. The information about the terminal that can share the COT initiated by terminal A may include at least one of the source ID or the destination ID associated with the transmission of terminal A. The source ID may be an ID or an address associated with the terminal that transmits the signal / channel. The destination ID may be an ID or an address associated with the terminal that receives the signal / channel. When terminal A transmits a signal / channel to terminal B, the source ID may indicate terminal A, and the destination ID may indicate terminal B.

[0145] Terminal A may transmit information about a sharing target (e.g., source ID and / or destination ID) to terminal B. The interpretation of the source ID and / or destination ID may vary according to the transmission scheme (e.g., unicast transmission, multicast transmission, broadcast transmission) of terminal A. The terminals that can share the COT initiated by terminal A may vary according to the source ID and / or destination ID.

[0146] When unicast SL communication is performed between terminal A and terminal B, the source ID may be the ID of terminal A, and the destination ID may be the ID of terminal B. Terminal B having the same ID as the destination ID indicated by the information about the shared target may transmit a signal / channel within a COT shared by terminal A having the source ID indicated by the information about the shared target. When a COT initiated by terminal A is shared with terminal B, the source ID of SL transmission of terminal B within the shared COT is the ID of terminal B, and the destination ID of SL transmission of terminal B within the shared COT is the ID of terminal A, and terminal B may transmit a signal / channel within the shared COT.

[0147] When multicast SL communication or broadcast SL communication is performed between terminal A and terminal B, the source ID may be the ID of terminal A. In multicast SL communication, the destination ID may be the ID or address of the group receiving the multicast SL transmission. In broadcast SL communication, the destination ID may be the ID or address of the group receiving the broadcast SL transmission. When terminal B receives a multicast SL transmission from terminal A within a COT initiated by terminal A, and the COT is shared with terminal B, terminal B may perform a multicast SL transmission having the same destination ID as the multicast SL transmission of terminal A or perform a multicast SL transmission for a group including terminal A within the COT shared by terminal A. When terminal A shares a COT for multicast SL transmission with terminal B, terminal B may perform a multicast SL transmission having the same destination ID as the multicast SL transmission or perform a multicast SL transmission for a group including terminal A within the COT shared by terminal A.

[0148] When terminal B receives a broadcast SL transmission from terminal A within a COT initiated by terminal A, and the COT is shared with terminal B, terminal B may perform a broadcast SL transmission having the same destination ID as the broadcast SL transmission of terminal A within the COT shared by terminal A or perform a broadcast SL transmission for a group including terminal A. When terminal A shares a COT for broadcast SL transmission with terminal B, terminal B may perform a broadcast SL transmission having the same destination ID as the broadcast SL transmission within the COT shared by terminal A or perform a broadcast SL transmission for a group including terminal A.

[0149] Terminal A may transmit COT configuration information including information about a shared target to terminal B. The information about the shared target may include an additional ID. The additional ID may be different from the destination ID of the SL transmission for terminal A. Terminal C having the same ID as the additional ID may transmit a signal / channel within the COT shared by terminal A. If the source ID of the SL transmission for terminal C is the same as the additional ID indicated by terminal A, terminal C may perform SL transmission within the COT shared by terminal A. Terminal C may be the same as or different from terminal B. When the source ID of the SL transmission for terminal C is the same as the additional ID indicated by terminal A, and the destination ID of the SL transmission for terminal C is the same as the source ID indicated by terminal A, terminal C may transmit a signal / channel within the COT shared by terminal A.

[0150] The COT configuration information may include a source ID and / or a destination ID associated with the transmission of terminal A. The source ID may be an ID associated with the terminal transmitting the signal / channel. The destination ID may be an ID associated with the terminal receiving the signal / channel. When terminal A transmits a signal / channel to terminal B, the source ID may indicate terminal A, and the destination ID may indicate terminal B.

[0151] The COT configuration information (e.g., COT sharing information) transmitted by terminal A may include information about the location of terminal A. For example, the COT configuration information may include information about the communication distance requirement of terminal A. Terminal A may transmit information about the coverage of terminal A. Information about the coverage of terminal A may be included in the COT configuration information. Terminal B may receive at least one of information about the location of terminal A, information about the communication distance requirement of the terminal, and information about the coverage of terminal A from terminal A. Terminal B may determine whether terminal B is within the coverage of terminal A based on the location of terminal B and the coverage of terminal A.

[0152] When terminal B is within the coverage of terminal A, terminal B may transmit a signal / channel within the COT shared by terminal A. In other words, the COT initiated by terminal A may be shared with terminal B. When terminal B is not within the coverage of terminal A, terminal B may not be able to transmit a signal / channel within the COT shared by terminal A. In other words, the COT initiated by terminal A is not shared with terminal B.

[0153] The COT initiated by terminal A can be shared with terminal B, and terminal B can perform communication using the COT. Terminal B can transmit a signal / channel to terminal A within the COT shared by terminal A. In other words, the destination of the signal / channel transmitted by terminal B within the COT shared by terminal A may include terminal A. Terminal B may not be able to transmit a signal / channel to a terminal other than terminal A within the COT shared by terminal A. In other words, within the COT shared by terminal A, signal / channel transmission to a destination other than the destination including terminal A cannot be performed.

[0154] The destination ID for terminal B's transmission within the COT shared by terminal A may include the ID of terminal A. The group corresponding to the destination ID of terminal B's groupcast SL transmission (or multicast SL transmission) within the COT shared by terminal A may include terminal A.

[0155] Terminal A may transmit COT configuration information (e.g., COT sharing information) using SCI. Terminal A may transmit a first-level SCI including COT configuration information. The COT configuration information included in the first-level SCI may include time domain information and / or frequency domain information of the COT. The time domain information of the COT may indicate a period from the transmission time of the first-level SCI to the end time of the COT. Alternatively, the time domain information of the COT may indicate a period from the transmission time of the first-level SCI to the start time when the COT is available. The frequency domain information of the COT may indicate the frequency resources of the COT. The COT configuration information included in the first-level SCI may include information about priority categories.

[0156] Terminal B may receive SCI (e.g., first-level SCI) from terminal A and identify COT configuration information (e.g., COT sharing information) included in the SCI. Terminal B may identify time domain information and / or frequency domain information of the COT included in the COT configuration information. Terminal B may identify information about priority categories included in the COT configuration information. When receiving the first-level SCI including the COT configuration information, terminal B may determine that the COT associated with the COT configuration information is available. Terminal B may transmit a signal / channel within the COT associated with the COT configuration information.

[0157] Terminal A may transmit a second level SCI including COT configuration information (e.g., COT shared information). The COT configuration information may be included in at least one of the first level SCI or the second level SCI. When the COT configuration information is transmitted through the first level SCI and the second level SCI, a portion of the COT configuration information may be included in the first level SCI, and the remaining portion of the COT configuration information may be included in the second level SCI.

[0158] The COT configuration information included in the first-level SCI may include time domain information and / or frequency domain information of the COT. The time domain information of the COT may indicate a period from the transmission time of the first-level SCI to the end time of the COT. Alternatively, the time domain information of the COT may indicate a period from the transmission time of the first-level SCI to the start time when the COT is available. The frequency domain information of the COT may indicate the frequency resources of the COT. The COT configuration information included in the first-level SCI may include information about priority categories.

[0159] The COT configuration information included in the second-level SCI may include time domain information and / or frequency domain information of the COT. The time domain information of the COT may indicate a period from the transmission time of the second-level SCI to the end time of the COT. Alternatively, the time domain information of the COT may indicate a period from the transmission time of the second-level SCI to the start time when the COT is available. The frequency domain information of the COT may indicate the frequency resources of the COT. The COT configuration information included in the second-level SCI may include information about priority categories.

[0160] The COT configuration information included in the second-level SCI may include information about the shared target. The information about the shared target may include the ID of the terminal that can use the COT (e.g., shared COT). The information about the shared target may include information about the location of the terminal that can use the COT (e.g., shared COT).

[0161] Terminal B may receive the second-level SCI and identify the COT configuration information included in the second-level SCI. Terminal B may identify the time domain information and / or frequency domain information of the COT included in the COT configuration information. Terminal B may identify the information about the priority category included in the COT configuration information. When receiving the second-level SCI including the COT configuration information (e.g., COT sharing information) from terminal A, terminal B may determine that the COT associated with the COT configuration information is available. The COT associated with the COT configuration information may be a COT initiated by terminal A.

[0162] Terminal B may transmit a signal / channel within the COT associated with the COT configuration information. Terminal B may receive information about a shared target from terminal A, and may identify whether terminal B is included in the shared target indicated by the information about the shared target. If terminal B is included in the shared target indicated by the information about the shared target, terminal B may transmit a signal / channel within the shared COT. If terminal B is not included in the shared target indicated by the shared target information, terminal B may not be able to transmit a signal / channel within the shared COT.

[0163] Terminal A may transmit SCI format 2-A including COT configuration information (e.g., COT sharing information). In this case, the range of terminals sharing the COT initiated by terminal A may vary according to the broadcast type indicator included in SCI format 2-A. Terminal B may receive SCI format 2-A from terminal A and may receive COT configuration information included in SCI format 2-A. In this case, terminal B may identify whether the COT associated with the COT configuration information is available based on the broadcast type indicator included in SCI format 2-A.

[0164] When the broadcast type indicator indicates unicast, the COT initiated by terminal A can be shared with the terminal performing unicast SL transmission. When terminal A performs unicast SL transmission for terminal B based on SCI format 2-A, and SCI format 2-A includes COT configuration information, terminal B can transmit signals / channels within the COT associated with the COT configuration information (e.g., the COT initiated by terminal A). Terminal B can use the COT configuration information and destination ID included in SCI format 2-A to identify whether the COT is available. When the COT initiated by terminal A is available, terminal B can transmit signals / channels within the COT.

[0165] When the destination of SL transmission of terminal B is terminal A, terminal B can perform SL transmission using the COT initiated by terminal A. When the destination ID of unicast SL transmission of terminal B is the ID of terminal A, terminal B can perform unicast SL transmission within the COT initiated by terminal A. When the destination ID included in the SCI for unicast SL transmission of terminal B is set to the ID of terminal A, terminal B can perform unicast SL transmission within the COT initiated by terminal A. In other words, unicast SL transmission of terminal B can be performed within the COT shared by terminal A.

[0166] When the destination of unicast SL transmission for terminal B is not terminal A, terminal B cannot perform unicast SL transmission within the COT initiated by terminal A. In other words, unicast SL transmission of terminal B cannot be performed within the COT shared by terminal A. In this case, terminal B can obtain a new COT for unicast SL transmission and perform unicast SL transmission within the new COT.

[0167] When the destination ID of the multicast SL transmission for the terminal B is the ID of the group to which the terminal A belongs, the terminal B can perform the multicast SL transmission within the COT initiated by the terminal A. When the destination ID included in the SCI for the multicast SL transmission of the terminal B is set to the ID of the group to which the terminal A belongs, the terminal B can perform the multicast SL transmission within the COT initiated by the terminal A. In other words, the multicast SL transmission of the terminal B can be performed within the COT shared by the terminal A.

[0168] When the destination ID of the multicast SL transmission for the terminal B is not the ID of the group to which the terminal A belongs, the terminal B cannot perform the multicast SL transmission within the COT initiated by the terminal A. In other words, the multicast SL transmission of the terminal B cannot be performed within the COT shared by the terminal A. In this case, the terminal B can obtain a new COT for the multicast SL transmission and perform the multicast SL transmission within the new COT.

[0169] When the destination ID of the multicast SL transmission for terminal B is the same as the destination ID of the SL transmission for terminal A, terminal B can perform the multicast SL transmission within the COT initiated by terminal A. When the destination ID included in the SCI for the multicast SL transmission for terminal B is the same as the destination ID of the SL transmission for terminal A, terminal B can perform the multicast SL transmission within the COT initiated by terminal A. When the destination ID of the multicast SL transmission for terminal B is different from the destination ID of the SL transmission for terminal A, terminal B cannot perform the multicast SL transmission within the COT initiated by terminal A. In this case, terminal B can obtain a new COT for multicast SL transmission and perform multicast SL transmission within the new COT.

[0170] Terminal B may perform broadcast SL transmission within the COT initiated by terminal A. Alternatively, terminal B may not be able to perform broadcast SL transmission within the COT initiated by terminal A. In this case, terminal B may obtain a new COT for broadcast SL transmission and perform broadcast SL transmission within the new COT.

[0171] When the broadcast type indicator indicates multicast, the shared target of the COT initiated by terminal A can be a terminal that receives multicast SL transmission. When terminal A uses SCI (e.g., SCI format 2-A) to perform multicast SL transmission on a group including terminal B and terminal C, and the SCI (e.g., SCI format 2-A) includes COT configuration information, terminal B and / or terminal C can perform SL transmission within the COT initiated by terminal A. Terminal B and / or terminal C can determine whether the COT is available based on the COT configuration information and destination ID included in the SCI (e.g., SCI format 2-A). When the COT initiated by terminal A is available, terminal B and / or terminal C can use COT to perform SL transmission.

[0172] When the COT initiated by terminal A is shared, and the destination of SL transmission for terminal B and / or terminal C is terminal A, terminal B and / or terminal C can perform SL transmission in the COT shared by terminal A. When the SL transmission of terminal B and / or terminal C is unicast SL transmission, and the destination ID for unicast SL transmission is the ID of terminal A, terminal B and / or terminal C can perform SL transmission in the COT shared by terminal A. When the destination ID included in the SCI for unicast SL transmission of terminal B and / or terminal C is set to the ID of terminal A, terminal B and / or terminal C can perform unicast SL transmission in the COT shared by terminal A. When the destination of unicast SL transmission for terminal B and / or terminal C is not terminal A, terminal B and / or terminal C cannot perform unicast SL transmission in the COT shared by terminal A. In this case, terminal B and / or terminal C can obtain a new COT for unicast SL transmission and perform unicast SL transmission in the new COT.

[0173] When the destination ID of the multicast SL transmission for terminal B and / or terminal C is the ID of the group to which terminal A belongs, terminal B and / or terminal C can perform the multicast SL transmission within the COT shared by terminal A. When the destination ID included in the SCI for the multicast SL transmission for terminal B and / or terminal C is the ID of the group to which terminal A belongs, terminal B and / or terminal C can perform the multicast SL transmission within the COT shared by terminal A. When the destination of the multicast SL transmission for terminal B and / or terminal C is not the group to which terminal A belongs, terminal B and / or terminal C cannot perform the multicast SL transmission within the COT shared by terminal A. In this case, terminal B and / or terminal C can obtain a new COT for multicast SL transmission and perform the multicast SL transmission within the new COT.

[0174] Terminal B and / or terminal C may perform broadcast SL transmission within the COT initiated by terminal A. Alternatively, terminal B and / or terminal C may not be able to perform broadcast SL transmission within the COT initiated by terminal A. In this case, terminal B and / or terminal C may obtain a new COT for broadcast SL transmission and perform broadcast SL transmission within the new COT.

[0175] When the broadcast type indicator indicates broadcast, the sharing target of the COT initiated by terminal A may be a terminal receiving broadcast SL transmission. When terminal A performs broadcast SL transmission using SCI (e.g., SCI format 2-A) and the SCI (e.g., SCI format 2-A) includes COT configuration information, the terminal receiving the SCI (e.g., SCI format 2-A) may perform SL transmission within the COT initiated by terminal A. The terminal may perform SL transmission using the COT shared by terminal A based on the COT configuration information included in the SCI (e.g., SCI format 2-A).

[0176] When the destination of the SL transmission is terminal A, the terminal can perform SL transmission within the COT shared by terminal A. When the destination ID of the unicast SL transmission for the terminal is the ID of terminal A, the terminal can perform unicast SL transmission within the COT shared by terminal A. When the destination ID included in the SCI for unicast SL transmission of the terminal is set to the ID of terminal A, the terminal can perform unicast SL transmission within the COT shared by terminal A. When terminal A is not the destination of the unicast SL transmission of the terminal, the terminal cannot perform SL transmission within the COT shared by terminal A. In this case, the terminal can obtain a new COT for unicast SL transmission and perform unicast SL transmission within the new COT.

[0177] When the destination ID of the multicast SL transmission for terminal B is the ID of the group to which terminal A belongs, terminal B can perform the multicast SL transmission within the COT shared by terminal A. When the destination ID included in the SCI for the multicast SL transmission for terminal B is the ID of the group to which terminal A belongs, terminal B can perform the multicast SL transmission within the COT shared by terminal A. When the destination of the multicast SL transmission for terminal B is not the group to which terminal A belongs, terminal B cannot perform the multicast SL transmission within the COT shared by terminal A. In this case, terminal B can obtain a new COT for the multicast SL transmission and perform the multicast SL transmission within the new COT.

[0178] The terminal may perform broadcast SL transmission within the COT shared by terminal A. Alternatively, the terminal may not be able to perform broadcast SL transmission within the COT shared by terminal A. In this case, the terminal may obtain a new COT for broadcast SL transmission and perform broadcast SL transmission within the new COT.

[0179] Fig.10 is a flow chart illustrating a second exemplary embodiment of a communication method in an unlicensed band.

[0180] Reference Fig.10 , terminal A may transmit a signal / channel and COT configuration information (e.g., COT sharing information) to terminal B. Terminal B may receive a signal / channel and COT configuration information from terminal A (S1010). The signal / channel and COT configuration information may be transmitted independently. Alternatively, the COT configuration information may be included in the signal / channel. The COT configuration information may be transmitted to terminal B via signaling. The signaling may be at least one of system information (SI) signaling, RRC signaling, MAC CE signaling, or PHY signaling.

[0181] Terminal B may compare the source ID of the signal / channel received from terminal A with the destination ID of the signal / channel to be transmitted by terminal B (S1020). The signal / channel transmitted by terminal A may be referred to as signal A, and the signal / channel to be transmitted by terminal B may be referred to as signal B. Terminal B may determine the COT to transmit signal B based on the result of step S1020.

[0182] When the source ID of signal A is the same as the destination ID of signal B, terminal B may determine whether the time and / or frequency resources for transmission of signal B belong to the time and / or frequency resources of the COT initiated by terminal A (S1030). Terminal B may determine the COT to transmit signal B based on the result of step S1030. When the time and / or frequency resources for transmission of signal B belong to the time and / or frequency resources of the COT initiated by terminal A, terminal B may transmit signal B within the COT initiated by terminal A (S1040). In other words, terminal B may share the COT initiated by terminal A.

[0183] When the source ID of signal A is determined to be different from the destination ID of signal B in step S1020, terminal B can obtain a new COT for transmission of signal B (S1050). Terminal B can transmit signal B within the new COT (S1060). When the time and / or frequency resources for transmission of signal B are determined to be time and / or frequency resources that do not belong to the COT initiated by terminal A in step S1030, terminal B can obtain a new COT for transmission of signal B (S1050). Terminal B can transmit signal B within the new COT (S1060).

[0184] Fig.11 is a flow chart illustrating a third exemplary embodiment of a communication method in an unlicensed band.

[0185] Reference Fig.11 , terminal A may transmit a signal / channel (e.g., signal A) and COT configuration information (e.g., COT sharing information) to terminal B. Terminal B may receive signal A and COT configuration information from terminal A (S1110). Signal A and COT configuration information may be transmitted independently. Alternatively, COT configuration information may be included in signal A. COT configuration information may be transmitted to terminal B via signaling.

[0186] Terminal B may compare the destination ID of signal A received from terminal A with the destination ID of the signal / channel (eg, signal B) to be transmitted by terminal B (S1120). Terminal B may determine the COT to transmit signal B based on the result of step S1120.

[0187] When the destination ID of signal A is the same as the destination ID of signal B, terminal B may determine whether the time and / or frequency resources for transmission of signal B belong to the time and / or frequency resources of the COT initiated by terminal A (S1130). Terminal B may determine the COT to transmit signal B based on the result of step S1130. When the time and / or frequency resources for transmission of signal B belong to the time and / or frequency resources of the COT initiated by terminal A, terminal B may transmit signal B within the COT initiated by terminal A (S1140). In other words, terminal B may share the COT initiated by terminal A.

[0188] When the destination ID of signal A is determined to be different from the destination ID of signal B in step S1120, terminal B can obtain a new COT for transmission of signal B (S1150). Terminal B can transmit signal B within the new COT (S1160). When the time and / or frequency resources for transmission of signal B are determined to be time and / or frequency resources that do not belong to the COT initiated by terminal A in step S1130, terminal B can obtain a new COT for transmission of signal B (S1150). Terminal B can transmit signal B within the new COT (S1160).

[0189] Fig.12 is a flow chart illustrating a fourth exemplary embodiment of a communication method in an unlicensed band.

[0190] Reference Fig.12 , terminal A may transmit at least one of the location information, communication distance requirement information, coverage information, or COT configuration information of terminal A to terminal B. Terminal B may receive at least one of the location information, communication distance requirement information, coverage information, or COT configuration of terminal A from terminal A (S1210). Terminal B may identify the coverage of terminal A based on the information received from terminal A (S1220).

[0191] Terminal B can identify whether terminal B exists within the coverage of terminal A based on the location of terminal B (S1230). When terminal B exists within the coverage of terminal A, terminal B can determine whether the time and / or frequency resources for the transmission of the signal / channel (e.g., signal B) to be transmitted by terminal B belong to the time and / or frequency resources of the COT initiated by terminal A (S1240). Terminal B can determine the COT to transmit signal B based on the result of step S1240. When the time and / or frequency resources for the transmission of signal B are determined to belong to the time and / or frequency resources of the COT initiated by terminal A, terminal B can transmit signal B within the COT initiated by terminal A (S1250). In other words, terminal B can share the COT initiated by terminal A.

[0192] When terminal B is determined not to exist within the coverage of terminal A in step S1230, terminal B may obtain a new COT for transmission of signal B (S1260). Terminal B may transmit signal B within the new COT (S1270). When the time and / or frequency resources for transmission of signal B are determined not to belong to the time and / or frequency resources of the COT initiated by terminal A, terminal B may obtain a new COT for transmission of signal B (S1260). Terminal B may transmit signal B within the new COT (S1270).

[0193] In addition, terminal A may configure the COT and share the COT with terminal B. In other words, terminal A may transmit COT sharing information (e.g., COT configuration information) to terminal B. Terminal B may receive the COT sharing information from terminal A and identify the COT shared by terminal A based on the COT sharing information. For example, terminal B may identify the time and / or frequency resources of the COT shared by terminal A. Terminal B may perform sidelink synchronization signal block (S-SSB) transmission within the shared COT.

[0194] S-SSB transmission can be performed according to a preset periodicity. When the S-SSB transmission time according to the S-SSB transmission periodicity belongs to the COT shared by terminal A, terminal B can perform S-SSB transmission in the shared COT. When the S-SSB transmission time according to the S-SSB transmission periodicity does not belong to the COT shared by terminal A, terminal B cannot perform S-SSB transmission in the shared COT. In this case, terminal B can perform a separate channel access process for S-SSB transmission, and can perform S-SSB transmission when the channel access process is successful.

[0195] S-SSB transmission can be performed in preconfigured resources (e.g., preconfigured frequency resources). If the frequency resources of S-SSB belong to the COT shared by terminal A, terminal B can perform S-SSB transmission in the shared COT. If the frequency resources of S-SSB do not belong to the COT shared by terminal A, terminal B cannot perform S-SSB transmission in the shared COT. In this case, terminal B can perform a separate channel access procedure for S-SSB transmission and perform S-SSB transmission when the channel access procedure is successful.

[0196] Terminal A may transmit PSCCH and / or PSSCH (e.g., control information and / or data) to terminal B. Terminal B may receive PSCCH and / or PSSCH from terminal A and may transmit HARQ feedback (e.g., HARQ-ACK response) for PSCCH and / or PSSCH to terminal A. HARQ feedback may be transmitted on PSFCH.

[0197] Terminal A may initiate a COT and share the COT with terminal B. For example, terminal A may transmit COT sharing information (e.g., COT configuration information) to terminal B. Terminal B may receive the COT sharing information from terminal A and identify the shared COT based on the COT sharing information. Terminal B may perform PSFCH transmission (e.g., transmission of HARQ feedback) within the COT shared by terminal A.

[0198] When the COT initiated by terminal A is shared with terminal B, and the PSFCH to be transmitted by terminal B includes at least one HARQ feedback for SL transmission (e.g., PSCCH transmission and / or PSSCH transmission) of terminal A, terminal B can perform PSFCH transmission within the COT shared by terminal A. PSFCH transmission can be a transmission of HARQ feedback for terminal A. Alternatively, PSFCH transmission can be a transmission of HARQ feedback for terminal A and a transmission of HARQ feedback for another terminal. If the time domain and / or frequency resources for PSFCH transmission of terminal B belong to the time domain and / or frequency resources of COT shared by terminal A, terminal B can perform PSFCH transmission within the COT shared by terminal A.

[0199] When the COT initiated by terminal A is shared with terminal B, and the PSFCH to be transmitted by terminal B does not include HARQ feedback for SL transmission (e.g., PSCCH transmission and / or PSSCH transmission) of terminal A, terminal B may not perform PSFCH transmission within the COT shared by terminal A. In this case, terminal B may perform a separate channel access procedure for PSFCH transmission and perform PSFCH transmission after the channel access procedure is successful.

[0200] Terminal A may transmit PSCCH and / or PSSCH to terminal B. Terminal A may transmit COT sharing information to terminal B. Terminal B may receive PSCCH and / or PSSCH from terminal A. Terminal B may receive COT sharing information from terminal A.

[0201] Terminal B can identify the COT shared by terminal A based on the COT sharing information received from terminal A. In other words, the COT initiated by terminal A can be shared with terminal B. Terminal B can perform PSCCH transmission and / or PSSCH transmission in the COT shared by terminal A. When the destination of the SL transmission of terminal B is terminal A, terminal B can perform SL transmission (e.g., PSCCH transmission and / or PSSCH transmission) in the COT shared by terminal A. When the destination of the SL transmission of terminal B includes terminal A, terminal B can perform SL transmission (e.g., PSCCH transmission and / or PSSCH transmission) in the COT shared by terminal A. When the time / frequency resources for the SL transmission of terminal B belong to the time / frequency resources indicated by the COT sharing information of terminal A (e.g., the time and / or frequency resources of the COT shared by terminal A), terminal B can perform SL transmission (e.g., PSCCH transmission and / or PSSCH transmission) in the COT shared by terminal A.

[0202] When the destination of SL transmission of terminal B does not include terminal A, terminal B cannot perform SL transmission (e.g., PSCCH transmission and / or PSSCH transmission) within the COT shared by terminal A. In this case, terminal B can perform a separate channel access procedure for SL transmission, and can perform SL transmission (e.g., PSCCH transmission and / or PSSCH transmission) when the channel access procedure is successful.

[0203] The method according to the present disclosure can be implemented as a program instruction executable by various computers and recorded on a computer-readable medium. The computer-readable medium may include a program instruction, a data file, a data structure or a combination thereof. The program instruction recorded on the computer-readable medium may be specially designed and configured for the present disclosure, or may be known and available to a technician in the field of computer software.

[0204] Examples of computer-readable media may include hardware devices, such as ROM, RAM, and flash memory, which are specifically configured to store and execute program instructions. Examples of program instructions include machine code generated by, for example, a compiler, and high-level language codes executed by a computer using an interpreter. The above exemplary hardware devices may be configured to run as at least one software module to perform embodiments of the present disclosure, and vice versa.

[0205] Although the embodiments of the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of the disclosure.

Claims

1. A method of a first terminal, comprising: receiving, from a second terminal, sharing information of a channel occupancy time (COT) initiated by the second terminal; determining whether a sidelink (SL) transmission of the first terminal is enabled within the COT based on the shared information; and In response to determining that the SL communication is possible within the COT, the SL transmission is performed within the COT shared by the second terminal.

2. The method according to claim 1, wherein: The shared information includes at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, or frequency domain information of the COT.

3. The method according to claim 1, wherein: The COT is initiated by a type 1 listen-before-talk (LBT) operation of the second terminal, and the SL transmission of the first terminal within the COT is performed based on a type 2 LBT operation, wherein the type 1 LBT operation is performed within a variable time period, while the type 2 LBT operation is performed within a fixed time period.

4. The method according to claim 1, wherein: When the SL transmission is a unicast SL transmission, the source of the unicast SL transmission is equal to the destination of the transmission of the second terminal, and the destination of the unicast SL transmission is equal to the source of the transmission of the second terminal, and the unicast SL transmission is performed within the COT shared by the second terminal.

5. The method according to claim 1, wherein: When the SL transmission is a multicast SL transmission and a destination of the multicast SL transmission is equal to a destination of a transmission of the second terminal, the multicast SL transmission is performed within the COT shared by the second terminal.

6. The method according to claim 1, wherein: When the SL transmission is a broadcast SL transmission and a destination of the broadcast SL transmission is equal to a destination of a transmission of the second terminal, the broadcast SL transmission is performed within the COT shared by the second terminal.

7. The method according to claim 1, wherein: The execution of the SL transmission includes: transmitting a sidelink synchronization signal block (S-SSB) within the COT.

8. The method according to claim 1, wherein: When the SL transmission is a physical sidelink feedback channel (PSFCH) transmission, and the PSFCH transmission includes a hybrid automatic repeat request (HARQ) feedback transmission for the second terminal, the PSFCH transmission is performed within the COT shared by the second terminal.

9. The method according to claim 1, wherein: When resources used for the SL transmission belong to resources of the COT, the SL transmission is performed within the COT.

10. A first terminal, comprising at least one processor, wherein: The at least one processor causes the first terminal to execute: receiving, from a second terminal, sharing information of a channel occupancy time (COT) initiated by the second terminal; determining whether a sidelink (SL) transmission of the first terminal is enabled within the COT based on the shared information; and In response to determining that the SL communication is possible within the COT, the SL transmission is performed within the COT shared by the second terminal.

11. The first terminal according to claim 10, wherein: The shared information includes at least one of a source identifier (ID), a destination ID, a channel access priority class (CAPC), a remaining COT duration, or frequency domain information of the COT.

12. The first terminal according to claim 10, wherein: The COT is initiated by a type 1 listen-before-talk (LBT) operation of the second terminal, and the SL transmission of the first terminal within the COT is performed based on a type 2 LBT operation, wherein the type 1 LBT operation is performed within a variable time period, while the type 2 LBT operation is performed within a fixed time period.

13. The first terminal according to claim 10, wherein: When the SL transmission is a unicast SL transmission, the source of the unicast SL transmission is equal to the destination of the transmission of the second terminal, and the destination of the unicast SL transmission is equal to the source of the transmission of the second terminal, and the unicast SL transmission is performed within the COT shared by the second terminal.

14. The first terminal according to claim 10, wherein: When the SL transmission is a multicast SL transmission and a destination of the multicast SL transmission is equal to a destination of a transmission of the second terminal, the multicast SL transmission is performed within the COT shared by the second terminal.

15. The first terminal according to claim 10, wherein: When the SL transmission is a broadcast SL transmission and a destination of the broadcast SL transmission is equal to a destination of a transmission of the second terminal, the broadcast SL transmission is performed within the COT shared by the second terminal.

16. The first terminal according to claim 10, wherein: In the execution of the SL transmission, the at least one processor further causes the first terminal to execute: transmitting a sidelink synchronization signal block (S-SSB) within the COT.

17. The first terminal according to claim 10, wherein: When the SL transmission is a physical sidelink feedback channel (PSFCH) transmission, and the PSFCH transmission includes a hybrid automatic repeat request (HARQ) feedback transmission for the second terminal, the PSFCH transmission is performed within the COT shared by the second terminal.

18. The first terminal according to claim 10, wherein: When resources used for the SL transmission belong to resources of the COT, the SL transmission is performed within the COT.

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