Method and apparatus for feedback in inter-terminal communication of communication system

Abstract

The present invention relates to a technique for feedback of inter-terminal communication of a communication system. The method performed by a first terminal may comprise the steps of: receiving a PSSCH in a time slot n from a second terminal through a sub-channel; determining a PRB set for sending a PSFCH corresponding to the PSSCH based on the time slot n and the index of the sub-channel; identifying a PRB set for transmitting the PSFCH from the PRB set; identifying a time slot configured to transmit the PSFCH in K time slots after the time slot n; and transmitting the PSFCH in the identified time slot using the identified PRB, wherein n and K are positive integers.

Description

Technical Field

[0001] The present disclosure relates to a feedback technology for communication between terminals in a communication system, and more particularly, to a feedback technology for communication between terminals in a communication system that enables transmission of a feedback channel on a side link in consideration of unlicensed frequency usage. Background Art

[0002] With the development of information and communication technology, various wireless communication technologies have been developed. Typical wireless communication technologies include Long Term Evolution (LTE) and New Radio (NR) defined in the 3rd Generation Partnership Project (3GPP) standard. LTE may be one of the fourth generation (4G) wireless communication technologies, and NR may be one of the fifth generation (5G) wireless communication technologies.

[0003] In order to handle wireless data that has rapidly increased after the commercialization of a fourth generation (4G) communication system (e.g., a long term evolution (LTE) communication system or an advanced LTE (LTE-A) communication system), a fifth generation (5G) communication system (e.g., a new radio (NR) communication system) using a frequency band higher than that of the 4G communication system (e.g., a frequency band of 6 GHz or more) as well as a frequency band of the 4G communication system (e.g., a frequency band of 6 GHz or less) is being considered. The 5G communication system may support enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and massive machine type communication (mMTC).

[0004] In addition, in the communication system, the terminal can use the side link (SL) to send or receive data. In addition, the terminal can notify other terminals whether the data has been received through the feedback channel of the side link. The side link can be configured in an unlicensed frequency band. When the terminal meets the conditions for using the unlicensed frequency, the terminal can send a feedback channel through the side link of the unlicensed frequency band. Here, the conditions for using the unlicensed frequency may need to identify the channel occupancy state of the radio resources desired to be used by the terminal. As a result of identifying the channel occupancy state, the radio resources that the terminal wishes to use may have been occupied by another terminal. In this case, the communication system can configure the transmission resources of the feedback channel to send the feedback channel by considering the conditions for using the unlicensed frequency.

[0005] Matters described as related art are prepared to facilitate understanding of the background of the present disclosure, and may include matters that are not known to one of ordinary skill in the technical field to which exemplary embodiments of the present disclosure belong. Summary of the invention

[0006]

Technical issues

[0007] The present disclosure aims to provide a feedback method and apparatus for inter-terminal communication in a communication system, wherein the method and apparatus are capable of transmitting a feedback channel on a side link while taking into account unlicensed frequency usage conditions.

[0008]

Technical solution

[0009] According to the first exemplary embodiment of the present disclosure, a feedback method for terminal-to-terminal communication in a communication system as a method of the first terminal for achieving the above-mentioned purpose may include: receiving a physical side link shared channel (PSSCH) from a second terminal through a subchannel in time slot n; determining a physical resource block (PRB) set for sending a physical side link feedback channel (PSFCH) for the PSSCH based on time slot n and an index of the subchannel; identifying a PRB for sending the PSFCH from the PRB set; identifying a time slot configured for sending the PSFCH after K time slots starting from time slot n; and sending the PSFCH using the identified PRB in the identified time slot.

[0010] In identifying a time slot configured for sending PSFCH after K time slots starting from time slot n, the first terminal can identify the time slot configured for sending PSFCH according to a PRB index determined based on at least one of the following: an index of a subchannel configured for PSSCH, time slot n, K time slots, an identifier (ID) of the first terminal, an ID of the second terminal, or a code q, where code q can represent a cyclic shift or a cyclic shift pair, and q can be a positive real number.

[0011] The feedback method may also include: identifying the transmission mode of PSSCH before sending PSFCH using the identified PRB in the identified time slot; and in response to identifying that the transmission mode is a unicast mode, identifying a hybrid automatic repeat request (HARQ) feedback state, wherein PSFCH is sent when the HARQ feedback state is in an enabled state.

[0012] The method may also include: identifying a transmission mode of the PSSCH before sending the PSFCH using the identified PRB in the identified time slot; and in response to identifying that the transmission mode is a multicast or broadcast mode, identifying a HARQ feedback state, wherein when the HARQ feedback state is in an enabled state, the PSFCH is sent based on a negative acknowledgement (NACK)-only scheme.

[0013] According to a second exemplary embodiment of the present disclosure, a feedback method for communication between terminals in a communication system as a method of a first terminal for achieving the above-mentioned purpose may include: receiving a physical side link shared channel (PSSCH) from a second terminal; generating a PRB set having a unit physical side link feedback channel (PSFCH) resource, each unit PSFCH resource including a combination of a PRB and a cyclic shift; configuring a candidate PSFCH set using a predetermined number of PRB sets in the PRB set based on an index of a subchannel through which the PSSCH is received; determining an index of a unit PSFCH resource for sending the PSFCH from the candidate PSFCH set; and sending the PSFCH to the second terminal using a unit PSFCH resource corresponding to the index of the determined unit PSFCH resource.

[0014] Generating a PRB set having unit PSFCH resources each including a combination of PRBs and cyclic shifts may include generating the PRB set based on at least one of: a transmission period of a PSFCH transmission timing resource (PSFCH TRP), a PSFCH type, a number of PRB sets, a number of cyclic shifts, or a number of repeated transmissions N_C_PSFCH.

[0015] The method may further include: before generating a PRB set having unit PSFCH resources each including a combination of PRBs and cyclic shifts, receiving information about a transmission period of a PSFCH TRP from a base station; receiving information about a PSFCH type from a base station; receiving information about the number of PRB sets constituting the PSFCH resources from a base station; and receiving information about the number of cyclic shifts constituting the PSFCH resources from a base station.

[0016] Determining the index of a unit PSFCH resource for sending PSFCH from a candidate PSFCH set may include determining the index of the unit PSFCH resource as a value obtained by performing a modulo operation on the sum of an identifier (ID) of the first terminal and an ID of the second terminal with the size of the candidate PSFCH set as the modulus.

[0017] The method may also include: defining a PSFCH sequence generation factor according to an index of a cyclic shift pair corresponding to an index of a unit PSFCH resource; and generating a Zadoff-Chu sequence constituting the PSFCH according to the PSFCH sequence generation factor, wherein the first terminal sends the PSFCH including the Zadoff-Chu sequence to the second terminal.

[0018] The unit PSFCH resource may be a unit interleaved PSFCH resource, each unit interleaved PSFCH resource comprising a combination of a PRB and a cyclic shift pair, the PRB set may be an interleaved PRB set, the candidate PSFCH set may be a candidate interleaved PSFCH set, the candidate interleaved PSFCH set comprising a predetermined number of interleaved PRB sets, which are respectively mapped to the indices of the cyclic shift pairs in the interleaved PRB set based on the indices of the subchannels through which the PSSCH is received, and the index of the unit PSFCH resource may be the index of the unit interleaved PSFCH resource.

[0019] The method may also include: forming a PSSCH-PSFCH transmission group, each PSSCH-PSFCH transmission group including a PSFCH time slot and a PSSCH time slot associated with the PSFCH time slot; mapping each PSSCH-PSFCH transmission group to a PSFCH opportunity time slot; determining an index of a cyclic shift pair for sending PSFCH based on at least one of an ID of the first terminal, an ID of the second terminal, or an index of the PSSCH-PSFCH transmission group; and determining an index of a unit interleaved PSFCH resource for sending PSFCH in the candidate interleaved PSFCH resources based on the determined index of the cyclic shift pair.

[0020] When the LBT process is required for transmitting the PSFCH and the LBT process is successful, the first terminal may transmit the PSFCH to the second terminal.

[0021] When the first terminal receives a non-transmission indication for PSFCH transmission, the first terminal may not send the PSFCH to the second terminal.

[0022] According to a third exemplary embodiment of the present disclosure, a feedback device for communicating between terminals in a communication system as a first terminal for achieving the above-mentioned purpose may include a processor, and the processor may enable the first terminal to execute: receiving a physical side link shared channel (PSSCH) from a second terminal; generating a PRB set having a unit physical side link feedback channel (PSFCH) resource, each unit physical side link feedback channel (PSFCH) resource including a combination of a PRB and a cyclic shift; configuring a candidate PSFCH set using a predetermined number of PRB sets in the PRB set based on an index of a subchannel through which the PSSCH is received; determining an index of a unit PSFCH resource for sending the PSFCH from the candidate PSFCH set; and sending the PSFCH to the second terminal using a unit PSFCH resource corresponding to the index of the determined unit PSFCH resource.

[0023] Before generating a PRB set having unit PSFCH resources each including a PRB and a cyclic shift, the processor also causes the first terminal to perform: generating a PRB set based on at least one of a transmission period of a PSFCH transmission timing resource (PSFCH TRP), a PSFCH type, a number of PRB sets, a number of cyclic shifts, or a number of repeated transmissions N_C_PSFCH.

[0024] Before generating a PRB set having unit PSFCH resources each including a combination of PRBs and cyclic shifts, the processor may also cause the first terminal to perform: receiving information about the transmission period of the PSFCH TRP from the base station; receiving information about the PSFCH type from the base station; receiving information about the number of PRB sets constituting the PSFCH resources from the base station; and receiving information about the number of cyclic shifts constituting the PSFCH resources from the base station.

[0025] In determining the index of a unit PSFCH resource for sending PSFCH from a candidate PSFCH set, the processor can also cause the first terminal to execute: determining the index of the unit PSFCH resource as a value obtained by performing a modulo operation on the sum of an identifier (ID) of the first terminal and the ID of the second terminal with the size of the candidate PSFCH set as the modulus.

[0026] The processor can also enable the first terminal to execute: define a PSFCH sequence generation factor based on the index of the cyclic shift pair corresponding to the index of the unit PSFCH resource; and generate a Zadoff-Chu sequence constituting the PSFCH based on the PSFCH sequence generation factor, wherein the first terminal sends the PSFCH including the Zadoff-Chu sequence to the second terminal.

[0027] The unit PSFCH resource may be a unit interleaved PSFCH resource each including a combination of a PRB and a cyclic shift pair, the PRB set may be an interleaved PRB set, the candidate PSFCH set may be a candidate interleaved PSFCH set including a predetermined number of interleaved PRB sets respectively mapped to the indices of the cyclic shift pairs in the interleaved PRB set based on the indices of the subchannels through which the PSSCH is received, and the index of the unit PSFCH resource may be the index of the unit interleaved PSFCH resource.

[0028] The processor can also cause the first terminal to perform: forming a PSSCH-PSFCH transmission group, each PSSCH-PSFCH transmission group including a PSFCH time slot and a PSSCH time slot associated with the PSFCH time slot; mapping each PSSCH-PSFCH transmission group to a PSFCH opportunity time slot; determining an index of a cyclic shift pair for sending PSFCH based on at least one of the ID of the first terminal, the ID of the second terminal, or the index of the PSSCH-PSFCH transmission group; and determining an index of a unit interleaved PSFCH resource for sending PSFCH in the candidate interleaved PSFCH resources based on the determined index of the cyclic shift pair.

[0029]

Beneficial Effects

[0030] According to the present disclosure, a method for configuring or transmitting a side chain feedback channel can be determined while satisfying the technical conditions required to transmit a signal / channel using an unlicensed frequency band. In addition, the present disclosure provides a method for configuring resources, selecting resources, and / or performing transmission of a PSFCH that has not yet been transmitted based on an LBT result. In addition, the present disclosure provides a method for configuring resources to satisfy the technical conditions of using resources equal to or greater than a certain proportion of a defined channel bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a conceptual diagram illustrating a first exemplary embodiment of a communication system.

[0032] Figure 2 is a block diagram illustrating an exemplary embodiment of communication nodes constituting a communication system.

[0033] Figure 3 is a conceptual diagram illustrating a first exemplary embodiment of a system frame in a communication system.

[0034] Figure 4 is a conceptual diagram illustrating a first exemplary embodiment of a subframe in a communication system.

[0035] Figure 5 is a conceptual diagram illustrating a first exemplary embodiment of a time slot in a communication system.

[0036] Figure 6 is a conceptual diagram illustrating a second exemplary embodiment of time slots in a communication system.

[0037] Figure 7 is a conceptual diagram illustrating a first exemplary embodiment of time-frequency resources in a communication system.

[0038] Figure 8 is a conceptual diagram showing a first exemplary embodiment of a downlink channel configured within a time slot in a communication system.

[0039] Fig. 9 is a conceptual diagram showing a second exemplary embodiment of a downlink channel configured within a time slot in a communication system.

[0040] Fig.10 is a conceptual diagram showing a first exemplary embodiment of a PDCCH monitoring opportunity in a communication system.

[0041] Fig.11 is a conceptual diagram illustrating a second exemplary embodiment of a PDCCH monitoring opportunity in a communication system.

[0042] Fig.12 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).

[0043] Fig.13 is a conceptual diagram illustrating a first exemplary embodiment of an SL resource.

[0044] Fig.14 is a conceptual diagram showing a first exemplary embodiment of a channel occupation time in a communication system.

[0045] Fig.15 is a conceptual diagram illustrating a second exemplary embodiment of a channel occupation time in a communication system.

[0046] Fig.16 is a conceptual diagram illustrating a first exemplary embodiment of a PSFCH resource in a communication system.

[0047] Fig.17 is a conceptual diagram illustrating a second exemplary embodiment of a PSFCH resource in a communication system.

[0048] Fig.18 is a conceptual diagram showing a first exemplary embodiment of a PSSCH-PSFCH transmission group and a method for indicating a PSFCH transmission LBT failure or non-transmission of a PSFCH. DETAILED DESCRIPTION

[0049] Since the present disclosure can be modified in various ways and has various forms, specific exemplary embodiments will be shown in the drawings and described in detail in the detailed description. However, it should be understood that this does not mean that the present disclosure is limited to specific exemplary embodiments, but on the contrary, the present disclosure is intended to cover all modifications and substitutions that fall within the spirit and scope of the present disclosure.

[0050] Relational terms such as first, second, etc. can be used to describe various elements, but these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first component can be named as a second component, and the second component can also be similarly named as the first component. The term "and / or" represents any one or combination of multiple related and described items.

[0051] In exemplary embodiments of the present disclosure, “at least one of A and B” may refer to “at least one of A or B” or “at least one of a combination of one or more of A and B”. Furthermore, “one or more of A and B” may refer to “one or more of A or B” or “one or more of a combination of one or more of A and B”.

[0052] When it is mentioned that a certain component is “coupled” or “connected” to another component, it should be understood that the certain component is directly “coupled” or “connected” to the other component, or another component may be provided therebetween. On the contrary, when it is mentioned that a certain component is “directly coupled” or “directly connected” to another component, it should be understood that no other component is provided therebetween.

[0053] The terms used in this disclosure are only used to describe specific exemplary embodiments and are not intended to limit the present disclosure. Unless the context clearly dictates otherwise, singular expressions include plural expressions. In this disclosure, terms such as "including" or "having" are intended to indicate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but it should be understood that these terms do not exclude the existence or addition of one or more features, numbers, steps, operations, components, parts, or combinations thereof.

[0054] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the present disclosure belongs. Terms commonly used and already appearing in dictionaries should be interpreted as having meanings that match the contextual meanings in the art. In this specification, unless explicitly defined, terms are not necessarily interpreted as having formal meanings.

[0055] The form of the present disclosure will be described in detail below with reference to the accompanying drawings. In describing the present disclosure, in order to facilitate the overall understanding of the present disclosure, the same numerals refer to the same elements throughout the description of the accompanying drawings, and their repeated description will be omitted.

[0056] A wireless communication network to which an exemplary embodiment according to the present disclosure is applied will be described. The wireless communication network to which an exemplary embodiment according to the present disclosure is applied is not limited to the content described below, and the exemplary embodiment according to the present disclosure can be applied to various wireless communication networks. Here, the wireless communication network can be used in the same sense as the wireless communication system.

[0057] Figure 1 is a conceptual diagram illustrating a first exemplary embodiment of a communication system.

[0058] refer to Figure 1 , the communication system 100 may include a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5 and 130-6. Here, the communication system may be referred to as a "communication network". Each of the plurality of communication nodes may support a communication protocol based on code division multiple access (CDMA), a communication protocol based on wideband CDMA (WCDMA), a communication protocol based on time division multiple access (TDMA), a communication protocol based on frequency division multiple access (FDMA), a communication protocol based on orthogonal frequency division multiplexing (OFDM), a communication protocol based on orthogonal frequency division multiple access (OFDMA), a communication protocol based on single carrier FDMA (SC-FDMA), a communication protocol based on non-orthogonal multiple access (NOMA), a communication protocol based on space division multiple access (SDMA), etc. Each of the plurality of communication nodes may have the following structure.

[0059] Figure 2 is a block diagram illustrating an exemplary embodiment of communication nodes constituting a communication system.

[0060] refer to Figure 2 , the communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to a network for 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 may be connected to communicate with each other through a bus 270. However, each component included in the communication node 200 may be connected to the processor 210 via a separate interface or a separate bus instead of the common bus 270. 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.

[0061] 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).

[0062] Reference again Figure 1 , the communication system 100 may include a plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 and a plurality of user equipments 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell, and each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. In addition, the second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. In addition, the fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5 and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. In addition, the first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1, and the sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

[0063] Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be referred to as a Node-B, an evolved Node-B (eNB), a base transceiver station (BTS), a radio base station, a radio transceiver, an access point, an access node, a road side unit (RSU), a digital unit (DU), a cloud digital unit (CDU), a radio remote head (RRH), a radio unit (RU), a transmission point (TP), a transmission and reception point (TRP), a relay node, etc. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 may be referred to as a user equipment (UE), a terminal, an access terminal, a mobile terminal, a station, a user station, a mobile station, a portable user station, a node, a device, etc.

[0064] Each of the plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 may support cellular communication (e.g., Long Term Evolution (LTE), Advanced LTE (LTE-A), etc., as specified in the Third Generation Partnership Project (3GPP)). The plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in the same frequency band or in different frequency bands. The plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul or a non-ideal backhaul, and exchange information with each other through the ideal backhaul or the non-ideal backhaul. In addition, each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can be connected to the core network through ideal backhaul or non-ideal backhaul. Each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can send a signal received from the core network to the corresponding UE 130-1, 130-2, 130-3, 130-4, 130-5, or 130-6, and send a signal received from the corresponding UE 130-1, 130-2, 130-3, 130-4, 130-5 or 130-6 to the core network.

[0065] Each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can support OFDMA-based downlink transmission and SC-FDMA-based uplink transmission. In addition, each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can support multiple-input multiple-output (MIMO) transmission (e.g., single-user MIMO (SU-MIMO), multi-user MIMO (MU-MIMO), large-scale MIMO, etc.), coordinated multi-point (CoMP) transmission, carrier aggregation (CA) transmission, unlicensed band transmission, device-to-device (D2D) communication (or proximity service (ProSe)), etc. Here, each of the plurality of UEs 130-1, 130-2, 130-3, 130-4, 130-5 and 130-6 may perform operations corresponding to operations of and supported by the plurality of base stations 110-1, 110-2, 110-3, 120-1 and 120-2.

[0066] The following will describe the operation method of the communication node in the wireless communication network. Even if a method (e.g., transmission or reception of a signal) performed at a first communication node in the communication node is described, the corresponding second communication node may also perform a method (e.g., reception or transmission of a signal) corresponding to the method performed at the first communication node. That is, when describing the operation of the terminal, the corresponding base station may perform an operation corresponding to the operation of the terminal. Conversely, when describing the operation of the base station, the corresponding terminal may perform an operation corresponding to the operation of the base station.

[0067] Figure 3 is a conceptual diagram illustrating a first exemplary embodiment of a system frame in a communication system.

[0068] refer to Figure 3 , the time resources in the communication system can be divided on a frame basis. For example, the system frames of the communication system can be configured continuously in the time domain. The length of the system frame can be 10 milliseconds (ms). The system frame number (SFN) can be set to one of #0 to #1023. In this case, 1024 system frames can be repeated in the time domain of the communication system. For example, the SFN of the system frame after system frame #1023 can be #0.

[0069] A system frame may include two half frames. The length of a half frame may be 5 ms. A half frame located in the start area of ​​the system frame may be referred to as 'half frame #0', and a half frame located in the end area of ​​the system frame may be referred to as 'half frame #1'. A system frame may include 10 subframes. The length of a subframe may be 1 ms. The 10 subframes in a system frame may be referred to as subframes #0-#9.

[0070] Figure 4 is a conceptual diagram illustrating a first exemplary embodiment of a subframe in a communication system.

[0071] refer to Figure 4 , a subframe may include n time slots, where n may be a natural number. Therefore, a subframe may consist of one or more time slots.

[0072] Figure 5 is a conceptual diagram illustrating a first exemplary embodiment of time slots in a communication system.

[0073] refer to Figure 5 , a time slot may include one or more symbols. For example, a time slot may include 14 symbols.

[0074] Figure 6 is a conceptual diagram illustrating a second exemplary embodiment of time slots in a communication system.

[0075] refer to Figure 6, a time slot may include one or more symbols. For example, a time slot may include 7 symbols.

[0076] Figure 5 and Figure 6 The length of a time slot in may vary according to the number of symbols contained in the time slot and the length of the symbol. Alternatively, the length of a time slot may vary according to a number μ. Here, μ may be a positive integer or 0. When the subcarrier spacing is 15kHz (e.g., μ=0), the length of the time slot may be 1ms. In this case, a 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, a system frame may include 20 time slots.

[0077] 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.

[0078] A symbol may be configured as a downlink (DL) symbol, a flexible (FL) symbol, or an uplink (UL) symbol. A slot consisting only of DL symbols may be referred to as a 'DL slot', a slot consisting only of FL symbols may be referred to as a 'FL slot', and a slot consisting only of UL symbols may be referred to as a 'UL slot'.

[0079] Figure 7 is a conceptual diagram illustrating a first exemplary embodiment of time-frequency resources in a communication system.

[0080] refer to Figure 7 , a resource consisting of one OFDM symbol on the time axis and one subcarrier on the frequency axis can be defined as a 'resource element (RE)'. A resource consisting of one OFDM symbol on the time axis and K subcarriers on the frequency axis can be defined as a 'resource element group (REG)'. A 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 In the time slot shown, N may be 14. N OFDM symbols may be used as a basic unit for resource allocation in the time domain.

[0081] The following will describe a method for sending and receiving data in a communication network. In downlink communication, downlink data can be sent via PDSCH. In uplink communication, uplink data can be sent via PUSCH. In the present disclosure, PDSCH may refer to downlink data or the resources through which downlink data is sent and received, and PUSCH may refer to uplink data or the resources through which uplink data is sent and received. The base station may send downlink control information (DCI) including configuration information (e.g., resource allocation information, scheduling information) of the PDSCH via a physical downlink control channel (PDCCH). In the present disclosure, PDCCH may refer to DCI (e.g., control information) or the resources through which DCI is sent.

[0082] The terminal may receive DCI on the PDCCH and identify the configuration information of the PDSCH contained 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.

[0083] Figure 8 is a conceptual diagram showing a first exemplary embodiment of a downlink channel configured within a time slot in a communication system.

[0084] refer to Figure 8 , a time slot may include 14 OFDM symbols in the time domain. Among the 14 OFDM symbols, some symbols may be configured as PDCCH regions, while the remaining symbols may be configured as PDSCH regions. For example, OFDM symbols #0-#1 may be configured as PDCCH regions, while OFDM symbols #2-#13 may be configured as PDSCH regions.

[0085] The PDCCH region can be configured from the beginning of the time slot, and the PDSCH region can be configured after the PDCCH region within the time slot. This mapping type can be referred to as "PDSCH mapping type A". When PDSCH mapping type A is used, the position of the demodulation reference signal (DMRS) in the time domain can be defined based on the first OFDM symbol of the time slot (e.g., OFDM symbol #0). For example, if the symbol offset of the DMRS is 2, the DMRS can be located in OFDM symbol #2 within the time slot.

[0086] Fig. 9 is a conceptual diagram showing a second exemplary embodiment of a downlink channel configured within a time slot in a communication system.

[0087] refer to Fig. 9, a time slot can include 14 OFDM symbols in the time domain. The PDCCH area can be configured in any symbol within the time slot, and the PDSCH area can be configured after the PDCCH area within the time slot. For example, symbols #7-#8 can be configured as the PDCCH area, and symbols #9-#13 can be configured as the PDSCH area. This mapping type can be referred to as "PDSCH mapping type B". When PDSCH mapping type B is used, the position of the DMRS in the time domain can be defined based on the first symbol (e.g., symbol #9) configured with PDSCH. For example, if the symbol offset of the DMRS is 2, the DMRS can be located in symbol #11 within the time slot.

[0088] The PDCCH monitoring method will be described below. The terminal may perform a PDCCH monitoring operation to receive DCI including scheduling information of the PDSCH. Configuration information for PDCCH monitoring may be sent from the base station to the terminal via a high-level message (e.g., a radio resource control (RRC) message). Configuration information for PDCCH monitoring may be included in control resource set (CORESET) information and / or search space information.

[0089] The CORESET information may include one or more of the following parameters.

[0090] -controlResourceSetId (e.g. CORESET ID)

[0091] -frequencyDomainResources (e.g. frequency resource information of CORESET)

[0092] -duration (e.g. time resource information of CORESET (e.g. search space))

[0093] -cce-REG-mappingType (e.g. PDCCH interleaving information)

[0094] -precoderGranularity (e.g. PDCCH precoding information)

[0095] -tci-StatesPDCCH

[0096] -tci-PresentInDCI

[0097] -pdcch-DMRS-ScramblingID (e.g. information about DMRS used for PDCCH demodulation)

[0098] The frequency resource information of the CORESET (e.g., information about the frequency resources where the PDCCH can exist) can be configured in units of n RBs. n can be a natural number. For example, n can be 6. The time resource information of the CORESET (e.g., information about the time resources where the PDCCH can exist) can be configured in units of m OFDM symbols. m can be a natural number. For example, m can be 1, 2, or 3.

[0099] The search space information may include one or more of the following parameters.

[0100] -searchSpaceId (e.g., search space ID)

[0101] -controlResourceSetId (e.g., the ID of the CORESET associated with the search space)

[0102] - monitoringSlotPeriodicityAndOffset (e.g., the period and offset of the PDCCH monitoring time slot, the period and offset of the PDCCH monitoring time slot can be configured in units of time slots)

[0103] -duration (e.g., the number of consecutive time slots to perform PDCCH monitoring)

[0104] -monitoringSymbolsWithinSlot (e.g., the first symbol to perform PDCCH monitoring within a time slot, the corresponding symbol can be indicated in the form of a bitmap)

[0105] -nrofCandidates (e.g., number of PDCCH candidates per aggregation level)

[0106] -searchSpaceType (e.g., Common Search Space (CSS), UE-specific Search Space (USS), DCI format to monitor)

[0107] The terminal may receive CORESET information and search space information from the base station. The terminal may identify the PDCCH monitoring opportunity based on the CORESET information and the search space information. The terminal may perform a monitoring operation on the PDCCH monitoring opportunity. The PDCCH monitoring opportunity may be configured as follows.

[0108] Fig.10 is a conceptual diagram showing a first exemplary embodiment of a PDCCH monitoring opportunity in a communication system.

[0109] refer to Fig.10, the length of the PDCCH monitoring opportunity in the time domain may be indicated by CORESET information (e.g., duration). The length of the PDCCH monitoring opportunity may be indicated in symbols. For example, the length of the PDCCH monitoring opportunity may be 2 symbols. In each time slot, symbols #0-#1 may be configured as PDCCH monitoring opportunities, and the period of the PDCCH monitoring opportunity time slot may be 1 time slot. In this case, the offset of the PDCCH monitoring opportunity time slot may be 0.

[0110] The terminal can use the search space information and the CORESET information associated with the corresponding search space information (for example, the CORESET information mapped to the CORESET ID contained in the search space information) to identify the PDCCH monitoring opportunity. For example, the terminal can identify the starting symbol (for example, symbol #0) of the PDCCH monitoring opportunity within the time slot based on the monitoringSlotPeriodicityAndOffset and monitoringSymbolsWithinSlot contained in the search space information, and can identify the length of the PDCCH monitoring opportunity based on the duration contained in the associated CORESET information (for example, 2 symbols). The terminal can perform a monitoring operation (for example, a blind decoding operation) on the identified PDCCH monitoring opportunity.

[0111] Fig.11 is a conceptual diagram illustrating a second exemplary embodiment of a PDCCH monitoring opportunity in a communication system.

[0112] refer to Fig.11 , multiple CORESETs (e.g., CORESET#0-#1) and multiple search spaces (e.g., search spaces #0-#3) may be configured. The base station may send information about CORESET#0 and information about CORESET#1 to the terminal, and may send information about search space #0, information about search space #1, and information about search space #2 to the terminal. The terminal may receive information about CORESET#0-#1 and information about search space #0-#2 from the base station, and may identify a PDCCH monitoring opportunity based on the information about CORESET#0-#1 and information about search space #0-#2.

[0113] Search space #0 may be associated with CORESET #0. Based on the information about search space #0 and the information about CORESET #0, the length of PDCCH monitoring opportunity #0 in the time domain may be 1 symbol, the starting symbol of PDCCH monitoring opportunity #0 may be symbol #7, the period of PDCCH monitoring opportunity #0 may be 1 time slot, and the offset for PDCCH monitoring opportunity #0 may be 0. Therefore, the terminal may perform a monitoring operation (e.g., a blind decoding operation) on PDCCH monitoring opportunity #0 configured in symbol #7 of each time slot. The terminal may detect DCI by performing a monitoring operation on PDCCH monitoring opportunity #0, and acquire PDSCH based on the information contained in the DCI.

[0114] Search space #1 may be associated with CORESET #1. Based on the information about search space #1 and the information about CORESET #1, the length of PDCCH monitoring opportunity #1 in the time domain may be 2 symbols, the starting symbol of PDCCH monitoring opportunity #1 may be symbol #0, the period of PDCCH monitoring opportunity #1 may be 2 time slots, and the offset of PDCCH monitoring opportunity #1 may be 0. Therefore, the terminal may perform a monitoring operation (e.g., a blind decoding operation) on PDCCH monitoring opportunity #1 configured in symbols #0-#1 of time slots #0 and #2. The terminal may detect DCI by performing a monitoring operation on PDCCH monitoring opportunity #1, and acquire PDSCH based on the information contained in the DCI.

[0115] Search space #2 may be associated with CORESET #1. Based on the information about search space #2 and the information about CORESET #1, the length of PDCCH monitoring opportunity #2 in the time domain may be 2 symbols, the starting symbol of PDCCH monitoring opportunity #2 may be symbol #4, the period of PDCCH monitoring opportunity #2 may be 2 slots, and the offset of PDCCH monitoring opportunity #2 may be 1. Therefore, the terminal may perform a monitoring operation (e.g., a blind decoding operation) on PDCCH monitoring opportunity #2 configured in symbols #4-#5 of slots #1 and #3. The terminal may detect DCI by performing a monitoring operation on PDCCH monitoring opportunity #2, and may acquire PDSCH based on the information contained in the DCI.

[0116] A side link (SL) communication method in a communication network will be described. SL communication can be performed in a licensed band and / or an unlicensed band. SL communication in an unlicensed band may be referred to as a side link unlicensed (SL-U) communication or an unlicensed side link (U-SL) communication. SL resources may be used to transmit SL signals and / or channels. SL resources may be configured on a resource pool basis. A resource pool may be referred to as an SL resource pool. A resource pool may include a Tx resource pool and / or an Rx resource pool. A Tx resource pool may be used for SL transmission, and an Rx resource pool may be used for SL reception. A Tx resource pool and an Rx resource pool may be distinguished from each other. A Tx resource pool and an Rx resource pool may be configured independently.

[0117] 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. Among all the time slots belonging to the period corresponding to the period of 10240ms, some time slots can be configured as resource pools. According to the time division duplex (TDD) configuration, the time slot including the downlink (DL) symbol may not be configured as a resource pool. The time slot including the resource in which the side link synchronization signal block (S-SSB) is transmittable may not be configured as a resource pool. The time slot that can be configured as a resource pool can be defined by a bitmap. In other words, the bitmap can indicate the time slot that can be configured as a resource pool.

[0118] In addition, the sidelink (SL) channel can be as follows. In other words, the sidelink channel can transmit traffic, data, etc. related to the sidelink service. Alternatively, the sidelink channel can transmit control information related to sidelink management and scheduling.

[0119] The SL channel can be used to send 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 / or a positioning reference signal (PRS)).

[0120] The PSSCH may be a channel for sending and receiving transport blocks (TBs), data, and / or traffic. The PSCCH may be a channel for sending and receiving control information. The PSFCH may be a channel for sending and receiving a hybrid automatic repeat request (HARQ) feedback indicating the reception status of the PSSCH. The sidelink synchronization signal block (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 synchronization signals (e.g., S-PSS and / or S-SSS).

[0121] Fig.12 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).

[0122] refer to Fig.12 , the resource pool may include one or more time slots, but does not include time slots that do not meet the configuration conditions of the resource pool and / or time slots in the multiple time slots that are not indicated by the bitmap. Non-contiguous time slots in the time domain can be interpreted as continuous time slots in the resource pool. In other words, even if the time slots configured as a resource pool are not continuous, the indexes of the time slots in the resource pool can be continuous.

[0123] 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 sending may refer to sending 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".

[0124] Fig.13 is a conceptual diagram illustrating a first exemplary embodiment of an SL resource.

[0125] refer to Fig.13, 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 (e.g., time slot positions) including PSFCH may be predefined. The time slots including PSFCH may be referred to as PSFCH time slots. The conditions for configuring the PSFCH time slots in the licensed band may be different from the conditions for configuring the PSFCH time slots in the unlicensed band. The HARQ feedback transmission operation in the PSFCH time slots of the licensed band may be different from the HARQ feedback transmission operation in the PSFCH time slots of the unlicensed band. The configuration information of the SL channel actually transmitted in the transmission resource may be sent through signaling (e.g., RRC message, SCI). The configuration information of the SL channel may include frequency resource information (e.g., the location of the frequency resource area), time resource information (e.g., the location of the time resource area), etc.

[0126] In an exemplary embodiment, the OFDM symbols that can be used for signal transmission in the time slot of the basic transmission unit can be defined according to the SL start symbol (e.g., sl-StartSymbol) and the SL symbol length (e.g., sl-LengthSymbols). Here, when the side link is configured in an unlicensed band, a sub-time slot with a time length less than the time slot length or an OFDMA symbol of any length can be used as an OFDM symbol for signal transmission. In an exemplary embodiment, the OFDM symbols that can be used for signal transmission in the time slot of the basic transmission unit can be defined according to an RRC message including sl-LengthSymbols. Alternatively, in another exemplary embodiment, the relevant information can be included in the SCI.

[0127] In the case of a sidelink subchannel, a subchannel can be configured with consecutive N PRB4subchannel Here, N PRB4subchannel It can be defined by RRC messages or base stations. Each subchannel can be configured continuously in a resource pool. When configuring the sidelink in an unlicensed band, the subchannel can be configured as a set of physically distributed PRBs. As an example, a subchannel can be configured with N PRBs at regular intervals. PRB4subchannel In the present disclosure, a structure of a subchannel configured as a set of PRBs at regular intervals may be defined as an "interleaved subchannel".

[0128] The base station may send 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 send 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 send the SL channel on 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.

[0129] The transmitting terminal may send an 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 contained 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 contained 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.

[0130] 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 if the LBT operation is successful, the terminal can use the channel during a specific time (e.g., channel occupancy time (COT)). For example, if the LBT operation of the terminal is successful, the COT can be initiated by the terminal, and the terminal can perform communication (e.g., SL-U communication) during the COT. Depending on specific conditions, other terminals (e.g., terminals that did not initiate the 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, the other terminals can perform communication within the shared COT.

[0131] The transmission unit (e.g., symbol configuration) within the COT may be different. Configuration information of the transmission unit within the COT may be sent via signaling (e.g., SCI). A symbol may refer to an OFDM symbol. Fig. 9 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.

[0132] The number of OFDM symbols used for PSCCH configuration may be 2 or 3. In this case, the starting position of the OFDM symbol used for PSCCH configuration may be defined as index [SL start symbol (eg, sl-StartSymbol)+1].

[0133] The operations, processes, control information and / or configuration information for working channel occupation in SL-U communication will be described. A working channel may refer to a frequency resource having a bandwidth of a predefined size. Resources (e.g., time resources, frequency resources, carriers, subcarriers, subchannels) of an unlicensed band 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)). Resources of an unlicensed band may be occupied by signals / channels sent and received between a base station and a terminal belonging to a cellular network. Resources of an unlicensed band may be occupied by signals / channels sent and received between terminals belonging to a cellular network.

[0134] In the present disclosure, a communication node (e.g., a base station, a terminal) that sends a signal / channel may be represented as a sending node, and a communication node (e.g., a base station, a terminal) that receives a signal / channel may be represented as a receiving node. In an unlicensed band, communication nodes may share a working channel. LBT operations may be performed to minimize interference between communication nodes. LBT operations may include an operation of checking whether a working channel is occupied by another signal before sending a signal / channel. If LBT operations are supported, a communication node (e.g., a sending node) may perform a random backoff procedure.

[0135] If 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 protect 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 that the terminal wishes to send within the CO.

[0136] 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 parameters determining the execution time of the LBT operation may be different. 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 the CW and perform a random backoff procedure based on the selected random backoff counter.

[0137] The fixed time period for performing the LBT operation may be determined based on the type of LBT operation and / or LBT parameters. The length of the fixed time period may be 16 μs or 25 μs.

[0138] In the present disclosure, an LBT process requiring a random backoff procedure may be represented as "LBT-type-A". In addition, the present disclosure may represent an LBT process with a fixed time length of 25 μs as "LBT-type-B". In addition, the present disclosure may represent an LBT process with a fixed time length of 16 μs as "LBT-type-C". As described above, LBT-Type-A may have a CO configuration (CO length in an exemplary embodiment) that varies depending on the LBT type or LBT parameters. In addition, LBT-Type-C may be defined as one of the LBT types, but this may mean that the terminal may not actually perform the LBT process and the terminal does not send a signal / channel within a fixed 16 μs time.

[0139] A communication node (e.g., a sending node) that has performed an LBT operation may send information about a CO protected by the LBT operation (e.g., CO configuration information) 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 of a priority category. The CO configuration information may include at least one of information about a starting time point of the CO, information about a length of the CO, or information about an ending time point of the CO. In the present disclosure, the term "time point" and the term "time" may be used as having the same meaning.

[0140] The receiving node may receive CO configuration information from the sending node, and identify LBT parameters for protecting the CO based on the CO configuration information. The receiving node may identify a priority category of the CO initiated by the sending node based on the LBT parameters.

[0141] In addition, the transmitting device may transmit information about the CO protected by the LBT process to the receiving device. The information about the CO (e.g., CO configuration information) may include one or more of information about the start time of the CO, information about the time length of the CO, and information about the end time of the CO. The receiving device may transmit a signal / channel at any time within the CO using the indicated CO configuration information.

[0142] The transmitting device can configure the COT based on the LBT type of 'LBT-Type-A'. COT can indicate time resources, frequency resources, or time-frequency resources. COT can be called CO or channel occupied resources (COR). Since the time-frequency resources in the unlicensed band are shared with other communication nodes, the time-frequency resources can be used discontinuously by a specific communication node. Therefore, signal / channel transmission in the unlicensed band can occur in the form of discontinuous bursts. Here, the burst form can represent a transmission structure configured with one or more time slots. In addition, the burst form may include a transmission structure configured with continuous OFDM symbols, the length of which is shorter than the time slot length. In sidelink communication, transmission resources can be configured continuously during COT.

[0143] Fig.14 is a conceptual diagram showing a first exemplary embodiment of a channel occupation time in a communication system.

[0144] refer to Fig.14 , the transmitting device may send an initial signal and / or a burst signal (e.g., PSSCH, PSFCH, PSCCH, reference signal) within the COT. Here, the initial signal may be a signal copied from the first symbol transmitted by the side link. Alternatively, the initial signal may be a signal configured as a cyclic prefix.

[0145] Fig.15 is a conceptual diagram illustrating a second exemplary embodiment of a channel occupation time in a communication system.

[0146] refer to Fig.15 , the transmitting device can send PSCCH and / or burst signal within the COT.

[0147] Hereinafter, the present disclosure will describe a method for allocating sidelink transmission resources and control information related to the allocation. First, the present disclosure will describe resource allocation (RA), which is a sidelink transmission resource allocation method. Transmission resources for sending or receiving signals / channels can be allocated to sidelink terminals.

[0148] 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 send 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.

[0149] In RA-mode 1, when transmission data occurs, the terminal can send a scheduling request (SR) for the transmission data to the base station, and the base station can use a dynamic grant (DG) based on the SR of the terminal to allocate resources (e.g., SL resources) to the terminal. In RA-mode 1, the base station can allocate periodic resources to the terminal in a semi-static manner, and the terminal can use the periodic resources allocated by the base station for SL communication.

[0150] The periodic resources allocated in a semi-static manner may be configuration grant (CG) resources. The base station may send allocation information of CG resources to the terminal. The allocation information of CG resources may include at least one of location information of CG resources, time resource information of CG resources, frequency resource information of CG resources, or periodic information of CG resources. According to the release process or deactivation process of CG resources, the CG scheme may be divided into CG-type 1 and CG-type 2. In CG-type 1, CG resources may be released through RRC signaling. In CG-type 2, CG resources may be deactivated through DCI signaling.

[0151] 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 send an SL signal / channel using the selected resource. The resource sensing / selection method according to RA-mode 2 may be divided 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 selects resources for TB transmission each time it wants to send 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.

[0152] When a semi-static scheme is used, the counter value for 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 for 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 monopolize. The specific time can be defined as RRI.

[0153] The base station may send 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. Continuous resources may be configured in a logical resource area of ​​the SL.

[0154] The first terminal may send 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 a resource (e.g., a resource selected by the first terminal) during the RRI indicated by the SCI. Information about the resource selected by the first terminal may be included in the SCI.

[0155] 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. Resources used during an RRI (e.g., an RRI value) indicated by an SCI may be identified by a resource sensing operation performed within the SSW.

[0156] The SCI may include scheduling information (e.g., scheduling information of a TB) and / or parameters applied to the transmission of the TB. The parameters applied to the transmission of the TB may be used for demodulation / decoding of the TB in the receiving end. The SCI may be divided into a first-level SCI (1st SCI) and a second-level SCI (2nd SCI). The first-level SCI may be sent on the PSCCH, and the second-level SCI may be sent on the PSSCH. The second-level SCI may be associated with the first-level SCI. The first level 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 the transmitting terminal of the PSSCH, information about the receiving terminal of the PSSCH, HARQ feedback information, or retransmission information.

[0157] Y transmission resources including a time slot for sending 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 sending a first-level SCI. In other words, the first transmission resource of the Y transmission resources may be a time slot for sending a first-level SCI. The time slots in which the remaining (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.

[0158] The first transmission resource scheduled may include N subchannel sub-channels. subchannel The first subchannel (eg, the starting subchannel) of the N subchannels may be the subchannel that transmits 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 about the N subchannels, information about the starting subchannel in the N subchannels) and / or frequency resource information of the third transmission resource (e.g., information about the N subchannels, information about the starting subchannel in the N subchannels). The number N of subchannels of the second transmission resource may be equal to or less than the number N of subchannels of the first transmission resource. subchannel The number N of subchannels of the third transmission resource may be the same as the number N of subchannels 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.

[0159] The first level SCI may include one or more information elements defined in Table 1 below.

[0160] [Table 1]

[0161]

[0162] The second level 2SCI 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.

[0163] [Table 2]

[0164] 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

[0165] In addition, the signal / channel configuration in the frequency-time domain or the signal / channel configuration in the time domain of the transmission resource allocated to the terminal or selected by the terminal may be as follows. As an exemplary embodiment, the signal / channel configuration of the PSSCH for TB transmission may be continuous OFDM symbols within the transmission resource. In the following, "symbol" may refer to "OFDM symbol". The terminal may configure and send the PSSCH with continuous symbols within a time slot period or transmission resource. Continuous symbols may include a demodulation reference signal (DMRS) for signal demodulation. The terminal may not configure the PSSCH or may not send the PSSCH in symbols that meet the following conditions. Here, the conditions may include one or more of the following conditions.

[0166] -PSSCH shall not be configured or transmitted in symbols other than those configured for the sidelink.

[0167] ○ Here, the symbol used for the side link may be defined according to the SL start symbol (e.g., sl-StartSymbol) and the SL symbol length (e.g., sl-LengthSymbols). Here, the SL start symbol may represent the index of the first symbol in consecutive symbols as long as the SL symbol length. Here, PSSCH allocation may start at the symbol indicated by the index (SL start symbol + 1). Here, a symbol for automatic gain control (AGC) may be configured at the position indicated by the SL start symbol. The symbol may be configured as the same symbol as the symbol indicated by the index (SL start symbol + 1).

[0168] —PSFCH can be configured in any time slot. If PSFCH is configured in any time slot, PSSCH cannot be configured or sent in the symbol configured for PSFCH. Here, the time slot configured with PSFCH can be a time slot that is periodically configured according to the PSFCH configuration period (e.g., 1, 2, or 4). Here, periodicity can be applied within a group of time slots configured for the side link.

[0169] -PSFCH can be configured in any time slot. If PSFCH is configured in any time slot, PSSCH cannot be configured or transmitted in the symbol immediately before the symbol configured for PSFCH.

[0170] - PSSCH shall not be configured or transmitted in the last symbol of the symbols configured for the sidelink.

[0171] In the above description, symbols not included in the PSSCH configuration during a transmission resource or a time slot period may be expressed as "gap symbols" or "gap OFDM symbols". In addition, the side link may be a link between terminals. Therefore, the received signal strength may vary depending on the location of the transmitting terminal and the receiving terminal. Therefore, AGC may be required to ensure that the signal is input to the receiver at an appropriate level according to the received signal strength. The symbol for AGC may be included in the first symbol of the PSCCH / PSSCH transmission. In addition, the symbol for AGC may be configured at the symbol position before the PSFCH transmission. In addition to the AGC symbol, the time required for transmission after signal reception may also be configured as a 'gap symbol'. Therefore, the last symbol of the transmission or the last symbol of the time slot may be configured as a gap symbol. In addition, even in a time slot where PSCCH / PSSCH symbols and PSFCH symbols are configured, the gap symbol may be configured after the last PSCCH / PSSCH symbol.

[0172] When a gap symbol is configured in a sidelink transmission in an unlicensed band, if the time of the gap symbol is longer than a predetermined time length, the resource may be occupied by another device in the unlicensed band. Therefore, when physically continuous resources are used in an unlicensed band, a gap symbol may not be configured. In addition, a certain number of samples of the previous symbol may be copied and configured as a cyclic prefix, so that the gap symbol is configured to have a length less than the length of one symbol. Alternatively, a certain number of samples of the following symbol may be copied and configured as a cyclic suffix, so that the gap symbol is configured to have a length less than the length of one symbol.

[0173] The length of the cyclic prefix may be a predefined value. Alternatively, the length of the cyclic prefix may be a value specified by the SCI. When using time slots that are continuous in time for transmission, the terminal may transmit the cyclic prefix by advancing the cyclic prefix of the first symbol of the time slot after the previous transmitted time slot by a defined length without an indication from the SCI.

[0174] In addition, PSFCH can be periodically configured within the SL resource area. The time slot in which PSFCH is configured may be referred to as a PSFCH time slot. PSFCH time slots may be configured according to periodicity. The period of a PSFCH time slot may be referred to as a PSFCH transmission timing resource (PSFCH TPR). PSFCH TRP may be configured as 1 time slot, 2 time slots, or 4 time slots. The PRBs in the frequency domain that can be used for PSFCH transmission may be indicated by a bitmap. When PSFCH transmission is configured with common PSFCH resources (or common PSFCH sets) and / or dedicated PSFCH resources (or dedicated PSFCH sets), the PRBs used for dedicated PSFCH resources (or dedicated PSFCH sets) may be indicated by a bitmap. The PRBs that may be used for PSFCH transmission may be all PRBs or some PRBs. One PSFCH may be sent in one PRB. Alternatively, in an unlicensed band, one PSFCH may be sent on one or more PRBs.

[0175] 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 first PSFCH time slot 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 in which the PSFCH is transmitted). PSFCH may be the period 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 where the PSCCH is configured. In the unlicensed band, a set of interleaved PRBs can enable X PRBs. In this case, the number of interleaved PRB groups can be 10 or less.

[0176] 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).

[0177] The PRB set used for PSFCH transmission can be determined based on the time slot n in which the PSSCH is transmitted and / or the index of the subchannel in which the PSSCH is transmitted. The PRBs in the PRB set and the codes carried by the PSFCH can 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.

[0178] A terminal receiving the PSSCH may send the PSFCH according to specified conditions. An example of a specified condition may be a case when the PSSCH is sent in unicast mode and HARQ feedback is enabled. Alternatively, an example of a specified condition may be a case when the PSSCH is sent in a multicast and / or broadcast transmission mode and HARQ feedback is enabled. Here, as HARQ feedback for the PSSCH occurring in the multicast and / or broadcast mode, only NACK may be sent based on a NACK-only scheme. The terminal may be configured with a PSFCH TPR from a resource pool. The configuration information may include one or more of the information described below.

[0179] —Information on the period of PSFCH TRP in the sidelink resource pool.

[0180] As an exemplary embodiment, the period of PSFCH TRP can be 1 time slot, 2 time slots or 4 time slots.

[0181] Fig.16 is a conceptual diagram illustrating a first exemplary embodiment of a PSFCH resource in a communication system.

[0182] refer to Fig.16 , the PSFCH transmission period in the licensed band may be 4 time slots. In addition, the HARQ feedback timing (ie, K_HARQ) of the PSSCH may be 3 time slots. The total number of subchannels may be 4. The number of PRB sets (PRB or PRB set) constituting the PSFCH resource N_PSFCH_PRB_Set may be 12.

[0183] In this regard, the PSFCH resources used for PSFCH transmission according to the PSFCH TPR may be defined as PRBs and / or cyclic shifts (CSs). Alternatively, the PSFCH resources used for PSFCH transmission according to the PSFCH TPR may be defined as a combination of PRBs and / or CSs. Hereinafter, the present disclosure will be described assuming a combination of PRBs and CSs. The terminal may receive information about the number of PRB sets (PRBs or PRB sets) constituting the PSFCH resources (i.e., N_PSFCH_PRB_Set) from the network or the base station. Fig.16 As an exemplary embodiment, the number N_PSFCH_PRB_Set of PRB sets (PRBs or PRB sets) constituting PSFCH resources may be 'F_1'.

[0184] In addition, the terminal may receive information about the number of cyclic shifts (i.e., N_PSFCH_CS) constituting the PSFCH resources from the network or base station. In addition, the terminal may receive information about the type of PSFCH from the network or base station. Therefore, the terminal may consider only one sidelink subchannel in the PSFCH resource configuration according to the type of PSFCH. Alternatively, the terminal may consider all number of subchannels in the PSFCH resource configuration according to the type of PSFCH. The terminal may determine the size of the PSFCH resources by considering at least one of N_PSFCH_PRB_Set, PSFCH TRP period information, the type of PSFCH, or N_PSFCH_CS. The N_PSFCH_PRB_Set PRB sets constituting the PSFCH resources may be divided according to the PSFCH TPR period information and / or the number of subchannels to form detailed PRB sets constituting the detailed PSFCH resources. As an exemplary embodiment, in Fig.16 In the example, the transmission period of PSFCHTRP can be F_2.

[0185] Therefore, the detailed PSFCH resources to be used by the terminal may be defined as different resources according to the subchannel. Fig.16 , the detailed PSFCH resources to be used by the terminal may belong to the dotted box of 'Candidate PSFCH resources (or candidate PSFCH set)'. Here, the present disclosure will be explained by defining the resources corresponding to the subchannels of PSSCH as detailed PSFCH resources. The size of the detailed PSFCH resources corresponding to PSSCH may be defined by at least one of the PSFCH type, the PSFCH transmission period, the number of subchannels, or N_PSFCH_CS. The index or configuration position of the detailed PSFCH resources corresponding to PSSCH may be defined according to the index of the subchannel to which PSSCH is sent (i.e., the PSSCH transmission subchannel index). As an exemplary embodiment, in Fig.16 In the embodiment, the index or configuration position of the detailed PSFCH resource corresponding to the PSSCH can be defined according to the PSSCH transmission subchannel index (IDX_SubCh).

[0186] In a detailed PSFCH resource, one PSFCH may be sent in a unit PSFCH resource. A unit PSFCH resource may be defined as a PRB and a cyclic shift pair. The index of the unit PSFCH resource may first be incremented according to the PRB index within the detailed PSFCH resource. Thereafter, when the index of the unit PSFCH resource reaches the PRB size of the detailed PSFCH resource, it may be incremented according to the cyclic shift pair index.

[0187] The terminal can calculate the index of the unit PSFCH resource for sending PSFCH. Alternatively, the terminal can identify the index of the unit PSFCH resource for sending PSFCH. When determining the index of the unit PSFCH resource through which the terminal will send PSFCH, the PSSCH time slot index (IDX_PSSCH4PSFCH) associated with the PSFCH time slot can be considered. The terminal can define the PSSCH time slot index associated with the PSFCH time slot by defining the time slot that is one time slot before the PSFCH time slot according to the PSFCH TRP as index 0, and defining the PSSCH time slot index to increase by 1 starting from index 0. Here, the terminal can derive the time slot gap from the information on the HARQ feedback timing (K_HARQ) of the PSSCH contained in the SCI. As an exemplary embodiment, in Fig.16 In the example, the PSSCH time slot index (IDX_PSSCH4PSFCH) associated with the PSFCH time slot can be 0, 1, 2, 3, etc.

[0188] In addition, when determining the index of the unit PSFCH resource through which the terminal will send the PSFCH, the ID of the terminal sending the PSSCH and / or the ID of the terminal sending the PSFCH may be considered together. As an exemplary embodiment, Fig.16 The ID of the terminal sending the PSSCH in may be ID_aa. Fig.16 In the example, the ID of the terminal sending the PSFCH may be ID_bb.

[0189] As an exemplary embodiment, the terminal may determine the index of the unit PSFCH resource for transmitting the PSFCH as a value obtained by performing a modulo operation on the sum of the ID of the terminal transmitting the PSSCH and the ID of the terminal transmitting the PSFCH with the size of the detailed PSFCH resource as the modulus. Fig.16 In the embodiment, f(ID_aa, ID_bb) can be 4. The terminal determines the PSFCH resource for sending the PSFCH using the index of the determined unit PSFCH resource. In addition, information for generating the Zadoff-Chu sequence constituting the PSFCH can be defined according to the cyclic shift pair index corresponding to the determined unit PSFCH resource index. The present disclosure will describe the PSFCH sequence generation factor. Here, the PSFCH sequence generation factor can be defined as one or more factors. In an exemplary embodiment, when the PSFCH sequence generation factor is defined according to the unit PSFCH resource index or the cyclic shift pair index, it can be defined as 'PSFCH sequence generation factor_A'. Alternatively, in an exemplary embodiment, when the PSFCH sequence generation factor is defined according to whether the HARQ feedback is ACK or NACK, it can be defined as 'PSFCH sequence generation factor_B'.

[0190] In addition, when the side link is configured in an unlicensed band, the PSFCH can be configured as described later. For signal transmission in an unlicensed band, a condition that the occupancy in the working bandwidth or the occupied bandwidth is equal to or greater than a predetermined ratio may be required. Therefore, the detailed PSFCH resources can be configured as an interleaved structure. Here, the PSFCH can be sent in one or more PRBs.

[0191] In addition, in the case of a PSFCH with an interleaved structure, as an exemplary embodiment, the same sequence can be used to send a PSFCH in multiple interleaved PRBs of a detailed PSFCH resource. As another exemplary embodiment, a sequence of a PSFCH can be sent in multiple PRBs as a sequence having a length corresponding to the number of REs of each of the multiple PRBs. In another exemplary embodiment, the value of N_PSFCH_CS (i.e., the number of cyclic shifts constituting the PSFCH resource) can be increased in the unlicensed band side link. In other words, the number of indexes in the code domain can be increased. In this case, when configuring the existing detailed PSFCH resources, the number of PRBs in the interleaved structure can be regarded as a unit resource.

[0192] refer to Fig.16 , in the candidate PSFCH resources, one PRB may be regarded as a unit of one PSFCH resource and may be mapped to one PSFCH resource index. In an exemplary embodiment, the PRB domain basic unit of the PSFCH resources in the candidate PSFCH resources in the unlicensed band may be a group of PRBs constituting one subchannel of the interleaved structure.

[0193] Fig.17 is a conceptual diagram illustrating a second exemplary embodiment of a PSFCH resource in a communication system.

[0194] refer to Fig.17 , the interleaved PSFCH resources in the unlicensed band may consist of three interleaved PSFCH resources and a cyclic shift pair index (CSPI). In an exemplary embodiment, the terminal may define the size of the detailed PSFCH resources by PSFCH type, PSFCH transmission period, number of subchannels, N_PSFCH_CS, interleaved PSFCH structure, etc. As an example, the number of PRBs that can be configured as detailed PSFCH resources may be The number of available PRBs constituting the PSFCH may be N_PSFCH_PRB_Set. The number of PRBs constituting one interlace structure may be N_Interlace_PRB. It can be defined by the following formula 1.

[0195] [Formula 1]

[0196]

[0197] When configuring PSFCH resources in an unlicensed band, the value that can be configured as N_PSFCH_CS can be defined differently according to the subcarrier spacing (SCS). As an exemplary embodiment, in the case of a 15kHz SCS, 10 can be configured as N_PSFCH_CS. In this case, one or more of 1, 2, 3, 6, 10, 20 (=2×10) and 30 (=3×10) can be configured as N_PSFCH_CS. As an exemplary embodiment, in the case of a 30kHz SCS, 5 can be configured as N_PSFCH_CS. In this case, one or more of 1, 2, 3, 6, 5, 10 (=2×5), 15 (=3×5) and 20 (=4×5) can be configured as N_PSFCH_CS. The configuration of CSPI can be defined according to the value of N_PSFCH_CS. As an exemplary embodiment, when the value of N_PSFCH_CS includes 1, 2, 3, 6, and 10, the CSPI value m O It may be defined as shown in Table 3 below. The CSPI value may be included or considered in the sequence generation for PSFCH transmission.

[0198] [Table 3]

[0199]

[0200] Alternatively, when the N_PSFCH_CS value is 1, 2, 3, or 6, the value of N_PSFCH_CS may be defined by including a variable that takes into account the SCS. Alternatively, CSPI may be defined. As an exemplary embodiment, μ may be 0, 1, and 2, depending on the SCS of 15 kHz, 30 kHz, and 60 kHz, respectively. In this case, the variable Δ μ It can be defined as 10, 5 or 3. In this case, the effective number of CSPIs in the unlicensed band can be as high as N_PSFCH_CS×Δ μ That is, N_PSFCH_CS can be 3, and when SCS = 30kHz, there can be a total of 15 CSPIs from index 0 to 14. Here, You can use the existing m o The values ​​are defined as Equations 2 and 3 below.

[0201] [Formula 2]

[0202]

[0203] [Formula 3]

[0204]

[0205] Here, N CPPI It can indicate the number of CSPI when the N_PSFCH_CS value is 1, 2, 3, or 6. Afterwards, the m used to generate the sequence o In the unlicensed band, it is possible to have m o mμo value. o The value is determined in the same way as the method, and can be determined using N_PSFCH_CS and CSPI index

[0206] In addition, regarding PSFCH resource determination, the terminal may determine CSPI by considering the ID of the terminal transmitting PSSCH and / or the ID of the terminal transmitting PSFCH. In addition, as an exemplary embodiment, an index of a PSSCH-PSFCH transmission group according to a PSFCH transmission period may be considered.

[0207] Here, the "PSSCH-PSFCH transmission group" may be a group obtained by grouping a predetermined number of PSSCH time slots and one PSFCH time slot according to the PSSCH time slot. Fig.16 , the PSSCH-PSFCH transmission group may indicate that time slots with IDX_PSSCH4PSFCH values ​​of 0, 1, 2, and 3 are grouped into one group.

[0208] Fig.18 is a conceptual diagram showing a first exemplary embodiment of a PSSCH-PSFCH transmission group and a method for indicating a PSFCH transmission LBT failure or a PSFCH non-transmission.

[0209] refer to Fig.18 , each of the three PSSCH-PSFCH transmission groups can be mapped to a time slot capable of PSFCH transmission. The terminal can send HARQ response information of the PSSCH of the time slot belonging to the PSSCH-PSFCH transmission group K or conflict information of the "reserved resources" in the PSFCH transmission resources of the nth time slot. However, in the case where LBT operation is required for PSFCH transmission, PSFCH transmission may become impossible due to LBT failure. Alternatively, the terminal may be instructed not to send PSFCH even in the time slot (or PSFCH opportunity) in which PSFCH resources are configured. In an exemplary embodiment, a terminal that has been instructed to share COT may perform an LBT process and may not send PSFCH in certain PSFCH opportunities during COT. The indication that PSFCH is not sent during COT (e.g., noTxPSFCH) will be described in more detail in the dynamic allocation scheme.

[0210] refer to Fig.18, PSFCH transmission may fail in time slots (n-8) and (n-4) of group K-2 and group K-1. Alternatively, PSFCH transmission may not be performed in time slots (n-8) and (n-4) of group K-2 and group K-1. In this case, the terminal may send the PSFCH by including the PSFCH in the nth PSFCH resource in time slots (n-8) and (n-4). To describe an exemplary embodiment, the index of each group that temporally precedes the PSFCH in the nth time slot may be defined as "Oc_Idx". In this case, the index of group K may be 0, and the index of group K-1 may be 1. The index of the group may be considered when determining the CSPI. Alternatively, the value of "Oc_Idx" may be defined with respect to N PSFCH transmission opportunities for one PSCCH / PSSCH transmission.

[0211] Here, the present disclosure will describe the resource configuration of PSFCH transmission of the group before group K or the method of determining the PSFCH resource index for it. It can be assumed that the number of resources available for PSFCH transmission is or here, It may represent one or more PRBs through which a sequence for a PSFCH is transmitted in an interleaved structure. Here, when determining a PSFCH resource for PSFCH transmission, CSPI may be calculated as shown in the following formula 4 or formula 5. Here, "mod" may represent a modulo operation.

[0212] [Formula 4]

[0213]

[0214] [Formula 5]

[0215]

[0216] In the above, if the ID of the terminal sending PSCCH is P ID , and the ID of the terminal sending PSFCH (that is, the ID of the terminal sending PSFCH) is M ID , then the index determination of the PSFCH resource can be defined as shown in the following formula 6 or formula 7.

[0217] [Formula 6]

[0218]

[0219] [Formula 7]

[0220]

[0221] The above description may assume that PSFCH is used for the HARQ response to PSSCH. PSFCH resources may be used to convey conflicting information for "reserved resources". Reserved resources may refer to PSSCH / PSCCH resources specified by the terminal using SCI. Therefore, the method for determining PSFCH resources and their resource indexes for sending conflicting information for reserved resources may be described in the same manner as the above-mentioned method for determining PSFCH resources and their resource indexes for the HARQ response to PSSCH. Therefore, the following will describe PSFCH transmission by taking the HARQ response to PSSCH reception as an example, but it can also be applied to the transmission of conflicting information for reserved resources.

[0222] In addition, the present disclosure will describe the common PSFCH resources (or common PSFCH sets) and / or dedicated PSFCH resources (or dedicated PSFCH sets) in all resources used for PSFCH transmission. Each of the common PSFCH resources (or common PSFCH sets) and / or dedicated PSFCH resources (or dedicated PSFCH sets) may consist of one or more PRBs. Here, the common PSFCH resources (or common PSFCH sets) may consist of C PRBs, and the dedicated PSFCH resources (or dedicated PSFCH sets) may consist of D PRBs. C and / or D may be the number of PRB units. Alternatively, C and / or D may be the number of interleaving units. In this case, C and / or D may be a natural number. When C and / or D are the number of interleaving units, the common PSFCH resources (or common PSFCH sets) and / or dedicated PSFCH resources (or dedicated PSFCH sets) are configured as PSFCH resources in an interleaved structure. In an exemplary embodiment, a common PSFCH resource (or a common PSFCH set) may represent a PRB commonly used by multiple terminals for PSFCH transmission. A bitmap may be used to indicate a PRB that can be used as a dedicated PSFCH resource (or a dedicated PSFCH set), and a terminal may use D PRBs specified by a bitmap in one interlace of an RB set as a dedicated PSFCH resource (or a dedicated PSFCH set).

[0223] The following are exemplary embodiments of PSFCH transmission resource configuration for common PSFCH resources (or common PSFCH sets) and / or dedicated PSFCH resources (or dedicated PSFCH sets). In each exemplary embodiment, the PSFCH transmission resources may be configured with one or more combinations of configuration conditions.

[0224] Configuration Conditions 1) PSFCH transmission resources can be configured as common PSFCH resources (or, common PSFCH sets) consisting of one interlace and dedicated PSFCH resources (or, dedicated PSFCH sets) consisting of X PRBs.

[0225] Configuration condition 2) PSFCH transmission resources can be configured as one interlace. Here, among the PRBs constituting one interlace, Y PRBs can be configured as dedicated PSFCH resources (or dedicated PSFCH sets), and the other PRBs can be configured as common PSFCH resources (or common PSFCH sets). Here, the PRBs of the common PSFCH resources (or common PSFCH sets) can be considered to have a common cyclic shift. Here, PRB unit or PRB-level cyclic shift can be applied.

[0226] Configuration condition 3) Dedicated PSFCH resources (or dedicated PSFCH sets) can be configured as one interlace.

[0227] Configuration condition 4) Dedicated PSFCH resources (or dedicated PSFCH sets) can be configured as one interlace, and PRB-level cyclic shift can be applied. Here, the cyclic shift can be hopped according to the time slot.

[0228] Configuration condition 5) The PSFCH resource may consist of (A+B) PRBs. In this case, A PRBs may be configured as dedicated PSFCH resources (or dedicated PSFCH sets), and B PRBs may be configured as common PSFCH resources (or common PSFCH sets). Here, B PRBs may be configured in a portion of the lowest PRB index and a portion of the highest PRB index in the frequency domain of one RB set.

[0229] In a common PSFCH resource (or a common PSFCH set), PRBs, interleaving, indexes of PRBs, and interleaving indexes may be defined according to the time slots and / or subchannels through which the PSSCH is received. The terminal may receive information about time slots, subchannels, common PSFCH resources (sets), etc. from the base station. In an exemplary embodiment, the common PSFCH resources (or common PSFCH sets) received from the base station may be used for PSFCH transmissions of all received PSSCHs requesting HARQ responses within a specific time period. As another exemplary embodiment, any PRB in a PSFCH resource used to send conflict information for reserved resources may be configured as a common PSFCH resource (or a common PSFCH set).

[0230] As another way of expressing it, a common PSFCH resource (or a common PSFCH set) may refer to a resource of a PRB used in common by each PSFCH transmission (or all PSFCH transmissions), and may refer to a resource in which some PRBs are used in common. As an exemplary embodiment, the PRB index with the minimum value and the PRB index with the maximum value in the resource pool may be included in the PSFCH resource configuration for all PSFCH transmissions. In an exemplary embodiment, one of the PSFCH resources in the interleaved structure may be configured as a common PSFCH resource (or a common PSFCH set). In other words, multiple PRBs constituting the interleaved structure PSFCH resources may become a common PSFCH resource (or a common PSFCH set).

[0231] Another exemplary embodiment of the configuration of a common PSFCH resource (or a common PSFCH set) may be the first index (index = 0) subchannel of an interleaved structure subchannel. Alternatively, it may be an interleaved subchannel with an intermediate index in an interleaved subchannel index configurable within an RB set. Here, an RB set may refer to a group of PRBs that make up the LBT bandwidth in a side link resource pool. Here, the intermediate index may be determined as floor(N / 2), floor(N / 2)+1, or floor(N / 2)-1 of the N interleaved subchannels configurable in the RB set. Alternatively, it may be the last index subchannel in the interleaved structure, or it may be a subchannel that has fewer PRBs than other subchannels. This is because, if the number of PRBs forming the resource set is not a multiple of the number of PRBs forming the interleaved structure subchannel, the number of PRBs in the subchannel that may include the last subchannel index may be smaller than that of other subchannels.

[0232] In another exemplary embodiment, a high-level message may define whether to configure a common PSFCH, how to configure the common PSFCH, and the location of the common PSFCH resource in an interleaved structure subchannel. Here, an interleaved subchannel for each RB set may be defined as a common PSFCH resource for each RB set. Here, when determining a dedicated PSFCH resource, a PRB used as an interleaved subchannel for a common PSFCH resource may not be included in the possible physical PRBs or number of PRBs. As another exemplary embodiment, some subcarriers or resource elements of a PRB used as an interleaved subchannel for a common PSFCH resource may be zero power (ZP) or empty subcarriers or empty REs. Here, the number of ZPs or empty REs may be X subcarriers or REs at both ends of each PRB. In this case, X may be a value of 0, 1, or 2. The value of X may be predefined or may be specified by a high-level message.

[0233] In addition, the present disclosure will describe the signal / channel or information transmitted using a common PSFCH resource (or a common PSFCH set). Different sequences generated using parameters selected for the PSFCH sequence configuration may be sent in a common PSFCH resource (or a common PSFCH set). Alternatively, a sequence or signal identical to the PSFCH used for PSFCH transmission may be sent in a common PSFCH resource (or a common PSFCH set). Alternatively, a portion of a PSFCH sequence or signal used for PSFCH transmission may be sent in a common PSFCH resource (or a common PSFCH set). Alternatively, a sequence generated by taking into account the total number of RPBs of a common PSFCH resource (or a common PSFCH set) and a dedicated PSFCH resource (or a dedicated PSFCH set) may be sent in a common PSFCH resource (or a common PSFCH set). In another exemplary embodiment, all terminals wishing to send a PSFCH may send the same sequence or signal in a common PSFCH resource (or a common PSFCH set). In another exemplary embodiment, each of all terminals that wish to send PSFCH may send a sequence or signal generated by considering information of each terminal in a common PSFCH resource (or a common PSFCH set). In another exemplary embodiment, a different sequence or signal may be sent for each RB set. Here, RB set index information, cell index, common PSFCH resource interleaving subchannel information, common PSFCH resource interleaving subchannel index, and information for S-SSB may be sent in a common PSFCH resource (or a common PSFCH set).

[0234] Here, the length of the sequence may be determined by considering the number of subcarriers of one PRB of a common PSFCH resource (or common PSFCH set). Alternatively, the length of the sequence may be determined by considering the number of subcarriers of multiple PRBs. As an example, the multiple PRBs may be PRBs constituting an interleaved structure.

[0235] A dedicated PSFCH resource (or dedicated PSFCH set) may indicate a resource used by a terminal for PSFCH transmission corresponding to any PSSCH. Alternatively, a dedicated PSFCH resource (or dedicated PSFCH set) may indicate a resource used for PSFCH transmission to convey conflicting information for any reserved resources.

[0236] In the case where common PSFCH resources (or common PSFCH sets) and dedicated PSFCH resources (or dedicated PSFCH sets) are configured in PSFCH transmission slots or symbols at the same time, when determining the PSFCH resource index in the dedicated PSFCH resources (or dedicated PSFCH sets), the PRB for common PSFCH resources (or common PSFCH sets) may not be included. As an exemplary embodiment, the terminal may receive information about the PRBs for configuring dedicated PSFCH resources (or dedicated PSFCH sets) from the base station as sl-PSFCH-RB-Set. Here, the information about the PRBs may include the positions of the PRBs for configuring the dedicated PSFCH resources (or dedicated PSFCH sets). Alternatively, the information about the PRBs may include the number of PRBs for configuring the dedicated PSFCH resources (or dedicated PSFCH sets). In this case, the positions of the PRBs for configuring the dedicated PSFCH resources (or dedicated PSFCH sets) may be pre-defined in the technical specifications. Alternatively, the positions of the PRBs for configuring the dedicated PSFCH resources (or dedicated PSFCH sets) may be pre-received from the base station via RRC messages, etc. Alternatively, the location of the PRB used to configure the dedicated PSFCH resource (or dedicated PSFCH set) can be received from the base station through the SCI. Alternatively, the location of the PRB used to configure the dedicated PSFCH resource (or dedicated PSFCH set) can be defined as an arbitrary resource set of the interleaving structure.

[0237] As another way of expressing the above description, sl-PSFCH-RB-Set may include information about PRBs used to configure common PSFCH resources (or common PSFCH sets). Here, the information about PRBs may include the positions of PRBs used to configure common PSFCH resources (or common PSFCH sets). Alternatively, the information about PRBs may include the number of PRBs used to configure common PSFCH resources (or common PSFCH sets).

[0238] The position of the PRB used to configure the common PSFCH resources (or common PSFCH set) may be predefined in the technical specification. Alternatively, the position of the PRB used to configure the common PSFCH resources (or common PSFCH set) may be received in advance from the base station through an RRC message or the like. Alternatively, the position of the PRB used to configure the common PSFCH resources (or common PSFCH set) may be received from the base station through an SCI. Alternatively, the position of the PRB used to configure the common PSFCH resources (or common PSFCH set) may be defined as an arbitrary resource set of an interleaved structure.

[0239] The terminal can use the above information to configure the detailed PSFCH resources and PSFCH resources of the dedicated PSFCH resources (or dedicated PSFCH set) with PRBs other than the PRBs of the common PSFCH resources (or common PSFCH set). Here, the method of configuring the detailed PSFCH resources or determining the PSFCH resource index (index in the dedicated PSFCH resource (or dedicated PSFCH set)) can follow the above method.

[0240] The method for configuring PSFCH resources in one RB set may be as follows: First, one interleaved subchannel may be designated as a common PSFCH resource. Here, the method for configuring the common PSFCH resource may be one of the above methods for configuring the common PSFCH resource using one interleaved subchannel.

[0241] Then, the PRBs of the remaining interleaved subchannels other than the used interleaved subchannels may be used to configure the dedicated PSFCH resources. Here, the dedicated PSFCH resources may be configured according to the number of unit PRBs M. Here, the value of M may be 1, 2, or 5. In addition, for M greater than 1, M PRBs of the PRBs constituting the same interleaved subchannel may be configured as one dedicated PSFCH resource. The value of M may be specified by a higher layer message.

[0242] The number of available resources for dedicated PSFCH resources can be determined by considering the remaining number of interleaved subchannels (N_R_IntSch), M, N_PSFCH_CS, PSFCH_TRP and N_C_PSFCH. Here, N_C_PSFCH can be N PSFCH transmission opportunities for one PSCCH / PSSCH. Here, N can be one of the values ​​1, 2, 3 or 4. The value of N can be specified by a high-level message according to an RB set. According to N, an RB set can be divided into N different sets so that the resources used for PSFCH transmission correspond to N opportunities. A terminal receiving a PSCCH / PSSCH can have up to N opportunities to send PSFCH based on the LBT result. In an exemplary embodiment, the number of configurable resources for dedicated PSFCH resources can be calculated as (N_R_IntSch×Δ μ / M). Here, Δ μ It can have different values ​​depending on the subcarrier spacing, and can be a value of 10 or 11 at 15kHz. μ At 30kHz, it can be a value of 5. (N_R_IntSch×Δ μ / M) can be increased to (N_R_IntSch×Δ μ / M)×N_PSFCH_Sym, where the increase is the number of OFDM symbols constituting the PSFCH (N_PSFCH_Sym). Here, the number of dedicated PSFCH resources consisting of detailed PSFCH resources is It can be defined as one of the following equations 8 to 11.

[0243] [Formula 8]

[0244]

[0245] [Formula 9]

[0246]

[0247] [Formula 10]

[0248]

[0249] [Formula 11]

[0250]

[0251] In the above, the number of subchannels may refer to the number of interleaved subchannels used for PSCCH / PSSCH transmission. The total configurable dedicated PSFCH resources may be calculated by considering Here, N_PSFCH_CS may have a default value of 1, 2, 3, or 6, and may be defined as a value added by considering N of N_C_PSFCH.

[0252] In the above, (N_R_IntSch×Δ μ / M) can represent the number of resources that can be configured as dedicated PSFCH resources.

[0253] In the above, dividing by N may represent distinguishing different resources in response to N transmission opportunities.

[0254] The terminal can be divided into N sets in the frequency domain, as many as N transmission opportunities, and within each set, M PRBs can be sequentially grouped into dedicated PSFCH resources within the same interlace. The terminal can determine the position or index of the PSFCH transmission resource in the above-distinguished N dedicated PSFCH resources within the set n corresponding to the nth transmission opportunity.

[0255] In an exemplary embodiment, the M value of the same dedicated PSFCH resource may be determined to be a value greater than N of N_C_PSFCH. Here, the terminal may apply a cyclic shift or sequence that can identify N in one dedicated PSFCH resource consisting of M PRBs to the dedicated PSFCH resource with a large value of M. Here, the cyclic shift may be a cyclic shift different from that of CPRI and may be applied differently depending on the value of N. Alternatively, the cyclic shift may be applied by considering N of both CPRI and N_C_PSFCH.

[0256] In another exemplary embodiment, the PSFCH may be sent in one or more PRBs among the M PRBs according to N. When configuring M PRBs, the number of PRBs constituting the interleaved subchannels may not be divided by M. This may be the case where 11 PRBs are configured as interleaved subchannels in the case of a 15kHz SCS. Alternatively, depending on the guard band configuration between RB sets, a certain number of subchannels may not be used as PSFCH transmission resources. As an exemplary embodiment, the 11th PRB may be excluded from the PSFCH resource configuration. Alternatively, as an exemplary embodiment, the PRBs included in the guard band may be included in the PSFCH resource configuration. However, the PRBs included in the guard band may actually be excluded from the PSFCH transmission.

[0257] When determining the dedicated PSFCH resource index, the value indicating N opportunities may correspond to the above-mentioned Oc_Idx. For N opportunities, the terminal may send PSFCH in resources corresponding to the N different PSFCH transmission resource sets or dedicated PSFCH resources (or dedicated PSFCH sets) defined above. In other words, assuming that N is 4, the Oc_Idx of the first PSFCH transmission resource or opportunity of a PSCCH / PSSCH may be 0 or 1. The Oc_Idx of the last PSFCH transmission resource or opportunity may be 3 or 4. In addition, in an exemplary embodiment, in order to change the resource position, the value of the nth opportunity or the value of Oc_Idx in the index of N transmission opportunities or N opportunities may be determined by considering the index of the time slot for sending PSCCH / PSSCH and / or the information of PSFCH_TRP. The terminal may determine the index of the set n corresponding to the nth transmission opportunity in the N dedicated PSFCH resources, determine the RB set for sending PSFCH according to the RB set for sending PSCCH / PSSCH, and then determine the index of the cyclic shift pair.

[0258] In addition, for N_C_PSFCH, the operation for N PSFCH transmission opportunities during COT can be as follows. For N_C_PSFCH within COT, as an exemplary embodiment, it can be specified that it is less than the number of N_C_PSFCHs that define PSFCH transmission opportunities within COT. Here, the defined N_C_PSFCH can refer to the number of transmission opportunities N_C_PSFCH configured in the RB concentration. The terminal that initiates COT and transmits information about COT can share COT with other terminals by including the above information in the information about COT. Here, from the perspective of the terminal sharing COT, as an exemplary embodiment, the PSFCH transmission opportunity can be defined as 1-bit information, and can be defined as only one PSFCH transmission opportunity or a PSFCH transmission opportunity that is smaller than the N_C_PSFCH configured by the upper layer. It can be assumed that the terminal that initiates and shares COT does not use PSFCH resources for PSFCH transmission during the time slot for sending PSCCH / PSSCH or before starting to share COT.

[0259] The above information may be included in the SCI and may be defined in relation to the COT sharing information. Alternatively, if the COT is shared without the above information, all terminals sharing the COT may perform the same operation. Here, one PSFCH transmission opportunity or a PSFCH transmission opportunity less than N_C_PSFCH may mean that the terminal sharing the COT only configures one or less than the same PSFCH transmission resource of N_C_PSFCH and sends PSFCH or receives response information. Here, when specified as one PSFCH transmission, the terminal may receive PSCCH / PSSCH and send PSFCH in the earliest resource capable of PSFCH transmission. Alternatively, one PSFCH transmission opportunity may be sent in the last configurable PSFCH resource during the COT period or length.

[0260] Alternatively, a PSFCH transmission opportunity may refer only to the PSFCH resources configurable based on the PSCCH / PSSCH of the last slot in the PSCCH / PSSCH sent from the terminal initiating the COT. Alternatively, a PSFCH transmission opportunity may be defined as the PSFCH transmission resource configured in the last slot of the COT period. Alternatively, a PSFCH transmission opportunity may be configured in one or more PSFCH transmission resources by considering the PSFCH configuration period of PSFCH_TRP and the value of N_C_PSFCH.

[0261] In this case, a PSFCH symbol or PSFCH resource corresponding to a period of (PSFCH_TRP×N_C_PSFCH) may be used. Alternatively, the last configurable PSFCH transmission resource during the COT period may be included together with the PSFCH resource according to the period of (PSFCH_TRP×N_C_PSFCH). In the above exemplary embodiment, the terminals sharing the COT may utilize the PSFCH resources available for PSFCH transmission during the COT period in N possible PSFCH transmission opportunities. In this case, each terminal sharing the COT may use information about an index corresponding to a corresponding transmission opportunity in the N opportunities. Here, the index information may represent a determined PSFCH transmission resource.

[0262] In addition, when the LBT process succeeds at any time in N_C_PSFCH PSFCH transmission opportunities, the terminal can send PSFCH regardless of the COT period. As an example, if PSFCH is sent at a time less than N_C_PSFCH opportunities, the terminal may not send reception response information or send PSFCH in the remaining PSFCH transmission opportunities.

[0263] In addition, regardless of the COT period, the terminal may not send reception response information or send PSFCH in the PSFCH transmission opportunity or configurable PSFCH transmission resource. As an exemplary embodiment, the terminal may not send any signal. In another exemplary embodiment, this may mean that the terminal uses PSFCH resources for PSCCH / PSSCH transmission. As another exemplary embodiment, this may mean that the terminal sends an arbitrary signal similar to the PSFCH signal. Here, an arbitrary signal can be defined as a signal obtained by using only information about a terminal sending PSFCH or a terminal sending PSCCH / PSSCH in the same time slot when generating a PSFCH signal or sequence.

[0264] Here, the terminal can use information about the terminal sending PSFCH or the terminal sending PSCCH / PSSCH in the same time slot to determine any PSFCH transmission resource index. In the above, the information about the terminal sending PSFCH can be the terminal or its ID information. In the above, the information about the terminal sending PSCCH / PSSCH in the same time slot can be the terminal or its ID information.

[0265] In addition, regarding the PSFCH transmission resource, the terminal can determine the time slot, symbol, index, etc. Here, as described above, the method of determining the PSFCH resource, etc. according to the predefined conditions can be defined as a 'pre-configuration method' in the present disclosure. In addition, the method of dynamically providing PSFCH transmission related information to the terminal through DCI and / or SCI can be defined as a 'dynamic allocation method' in the present disclosure.

[0266] The PSFCH transmission related information of the dynamic allocation method may include at least one of the following a) to d).

[0267] -a) Whether PSFCH is sent in PSFCH timing

[0268] -b)PSFCH resource index

[0269] -c) LBT type used for PSFCH transmission

[0270] -d)PSFCH transmission symbol

[0271] In the PSFCH transmission related information, the PSFCH timing may refer to a PSFCH transmission timing of a time slot that may include a PSFCH transmission resource according to a PSFCH transmission period.

[0272] The base station may generate DCI including PSFCH transmission related information. In addition, the base station may send DCI including PSFCH transmission related information to the terminal. The terminal may receive DCI including PSFCH transmission related information from the base station. Therefore, the terminal may obtain PSFCH transmission related information from the received DCI. Then, the terminal may generate SCI including the obtained PSFCH transmission related information. The terminal may provide SCI including PSFCH transmission related information to other terminals. Therefore, other terminals may receive SCI including PSFCH transmission related information from the terminal. Then, other terminals may obtain PSFCH transmission related information from the received SCI. On the other hand, the terminal may configure one or more of the PSFCH transmission related information as SCI. In addition, the terminal may provide SCI including one or more of the PSFCH transmission related information to other terminals. Therefore, other terminals may receive SCI including one or more of the PSFCH transmission related information from the terminal. Then, other terminals may obtain PSFCH transmission related information from the SCI.

[0273] In the case of RA-mode 1, the base station knows the scheduling status of the resource pool of RA-mode 1, so the base station can use PSFCH transmission related information to control PSFCH transmission, PSFCH transmission resources, configuration of PSFCH transmission resources, etc.

[0274] Information a) in the PSFCH transmission related information may be information indicating that symbols configured for PSFCH transmission in the PSFCH opportunity indicated by the information a) are not used for PSFCH transmission. A terminal that receives the PSFCH transmission related information including the information a) may delay PSFCH transmission by sending PSFCH in a PSFCH opportunity different from the PSFCH opportunity indicated by the information a).

[0275] In addition, the terminal may expect that the resources of the PSFCH opportunity indicated by information a) may be occupied by other signals according to information a) in the PSFCH transmission related information. In the present disclosure, the restriction on PSFCH transmission according to information a) can be described by defining it as PSFCH not transmitting "noTxPSFCH".

[0276] refer to Fig.18 According to information a), the terminal may not send PSFCH in the PSFCH opportunities of time slots (n-8) and (n-4). However, information a) may be specific to the receiving terminal. Therefore, other terminals may send PSFCH in the PSFCH opportunities of time slots (n-8) and (n-4).

[0277] The information b) in the PSFCH transmission related information may include information on an index for transmitting the PSFCH in the detailed PSFCH resource as index information for the PSFCH resource. Here, the index information for the PSFCH resource may include information on a PSFCH opportunity (time slot).

[0278] The information c) in the PSFCH transmission related information may be information about the LBT type of PSFCH transmission. The LBT type during the shared COT may be designated as LBT-Type C, which means that the LBT process for PSFCH transmission is not actually performed.

[0279] The information d) in the PSFCH transmission related information may include the configuration or position of the symbols of the PSFCH resources used for PSFCH transmission. During the shared COT, a cyclic prefix or cyclic suffix may be additionally configured in the gap symbol before or after the PSFCH transmission. In another exemplary embodiment, the position of the PSFCH symbol may be specified. In COT sharing, the PSFCH symbol may be configured in the last two symbols of the time slot. The PSFCH resources may be configured together with the above-mentioned pre-configuration method and dynamic allocation method.

[0280] Example 1

[0281] The PSFCH resources according to the preconfiguration method can be configured according to a defined pattern or periodicity. The PSFCH resources according to the dynamic allocation method can be configured within the resource time slot configured during the COT period or continuously configured. In more detail, the preconfiguration method can be used when there are PSFCH transmission resources or transmission opportunities between time slots capable of PSFCH transmission according to LBT success. Here, the terminal performing the LBT process can be a terminal that wishes to send PSFCH. Alternatively, if a terminal sends PSFCH when another terminal performs the LBT process and shares the COT, the preconfiguration method can be used.

[0282] The dynamic allocation method may include a case where a terminal that performs an LBT process and provides information for sharing COT activates or specifies PSFCH transmission resources using DCI or SCI during the COT period. Here, activation may mean activating PSFCH transmission resources or transmission opportunities according to resource configuration information predefined as an RRC message, etc. Here, designation may include allocating PSFCH resources after X time slots or allocating to time slot Y within the COT. Alternatively, a terminal that transmits PSSCH during the COT period may be configured to indicate PSFCH transmission via SCI.

[0283] Another exemplary embodiment of the dynamic allocation method may include activating or designating a PSFCH transmission resource when transmission is configured in a continuous time slot. Here, activation may mean activating a PSFCH transmission resource or a transmission opportunity according to resource configuration information predefined as an RRC message or the like. Here, designation may include allocating a PSFCH resource after X time slots starting from a start time slot of the continuous time slots or allocating a PSFCH resource to a time slot Y in the continuous time slots. Alternatively, designation may designate the last time slot of the continuous time slots.

[0284] In the above, information about X or Y can be defined by including bits of arbitrary length in a field of DCI or SCI. As described above, in the case where the PSFCH transmission resource is designated as the last time slot, the PSFCH resource configuration state or resource configuration information can be included in the DCI or SCI. Here, the terminal sending the PSFCH in the corresponding time slot can send the PSFCH after performing the LBT process of LBT-type B or LBT-type C. In addition, the terminal sending the PSFCH in the corresponding time slot can send the extended cyclic prefix within the protection symbol.

[0285] Information about the LBT type and / or the length of the extended cyclic prefix may be included in the DCI or SCI. In addition, the above-mentioned dynamically allocated PSFCH resources may be configured using all or part of the resources used for PSSCH / PSCCH transmission. When a portion of the resources used for PSSCH / PSCCH transmission is configured as a PSFCH resource, different terminals may be configured with different resource portions and use them for PSFCH transmission. When a portion of the resources used for PSSCH / PSCCH transmission is used for PSFCH transmission, the terminal may send PSFCH after performing the LBT process of LBT-Type C. In addition, when a portion of the resources used for PSSCH / PSCCH transmission is configured as a PSFCH resource, the terminal may send a PSFCH with a cyclic prefix in the portion of the resources, the cyclic prefix having an extended cyclic prefix length pre-specified or configured by an RRC message.

[0286] Example 2

[0287] The PSFCH resources according to the pre-configuration method can be configured according to a defined pattern or periodicity. The PSFCH resources according to the dynamic allocation method can be configured as resources in the PSSCH / PSCCH transmission time slot. The PSFCH resource configuration state or PSFCH resource configuration information may be included in the DCI or SCI. Here, the terminal sending the PSFCH in the corresponding time slot may send the PSFCH after performing the LBT process of LBT-Type B or LBT-Type C.

[0288] In addition, the terminal that sends PSFCH in the corresponding time slot can send the extended cyclic prefix within the protection symbol. Information about the length of the LBT type and / or extended cyclic prefix information can be included in the DCI or SCI. In addition, the PSFCH resources dynamically allocated as described above can be configured using all or part of the resources for PSSCH / PSCCH transmission. When a part of the resources for PSSCH / PSCCH transmission consists of PSFCH resources, different terminals can receive parts in different resources from the base station and use them for PSFCH transmission. When a part of the resources for PSSCH / PSCCH transmission is configured as PSFCH resources, different terminals can be configured with different parts of resources and use them for PSFCH transmission. When a part of the resources for PSSCH / PSCCH transmission is used for PSFCH transmission, the terminal can send PSFCH after performing the LBT process of LBT-type C. In addition, when a part of the resources for PSSCH / PSCCH transmission is configured as PSFCH resources, the terminal can send PSFCH with a cyclic prefix in the partial resources, and the cyclic prefix has an extended cyclic prefix length pre-specified or configured by an RRC message.

[0289] [According to operational definition of LBT failure]

[0290] In PSFCH transmission, the terminal may be unable to send PSFCH according to the result of the LBT process in the unlicensed band. At this time, the terminal may send PSFCH according to one or more of the following exemplary embodiments.

[0291] Example Embodiment A

[0292] Each PSCCH / PSSCH may have more than one PSFCH opportunity. Fig.18 Describe the method.

[0293] Exemplary Embodiment B

[0294] Exemplary embodiment B may correspond to a method of dynamically specifying the location of PSFCH transmission resources, which is described as a dynamic allocation method. Alternatively, the transmission of PSFCH may be reconfigured to a terminal in which PSFCH transmission has failed through COT sharing, and the terminal may send the PSFCH that previously failed to transmit. Here, the base station may instruct the terminal to send PSFCH by including information required to determine the transmission resources of the PSFCH to be attempted again. The information required to determine the transmission resources of the PSFCH may include, for example, a PSFCH transmission resource index. In addition, the information required to determine the transmission resources of the PSFCH may include information about Fig.18 Alternatively, the information required to determine the transmission resources of the PSFCH may include such information as Fig.18 As another exemplary embodiment, the PSFCH transmission resource index may be determined based on a combination of one or more of information about the transmission slot of the PSCCH / PSSCH corresponding to the failed PSFCH, information about the transmission slot for the failed PSFCH, information about the transmission resource index of the failed PSFCH, an arbitrary value included when indicating PSFCH transmission again, and the like.

[0295] Example Embodiment C

[0296] Exemplary embodiment C may correspond to a method of performing non-numeric HARQ feedback and one-shot HARQ feedback based on a trigger.

[0297] Example Embodiment D

[0298] There may be a method in which a terminal that needs to perform PSFCH transmission transmits PSFCH information by including the PSFCH information in PSCCH / PSSCH transmission. In this case, a modified SCI or a new SCI including relevant fields may be defined. Here, the HARQ process and ACK / NACK information may be configured and transmitted in one field. In this case, the HARQ process may be indicated by a value configured in the received PSCCH corresponding to the PSFCH transmission.

[0299] The operation of the method according to the exemplary embodiment of the present disclosure can be implemented as a computer-readable program or code in a computer-readable recording medium. The computer-readable recording medium may include various recording devices for storing data that can be read by a computer system. In addition, the computer-readable recording medium can store and execute a program or code that can be distributed in a computer system connected via a network and read by a computer in a distributed manner.

[0300] The computer readable recording medium may include a hardware device specially configured to store and execute program commands, such as ROM, RAM or flash memory. The program command may include not only the machine language code created by the compiler, but also the high-level language code that can be executed by the computer using an interpreter.

[0301] Although certain aspects of the present disclosure have been described in the context of an apparatus, these aspects may be indicated according to the corresponding description of the method, and a block or apparatus may correspond to the steps of the method or features of the steps. Similarly, the aspects described in the context of the method may be represented as features of the corresponding blocks or items or corresponding apparatuses. Part or all of the steps of the method may be performed by (or using) a hardware device (e.g., a microprocessor, a programmable computer, or an electronic circuit). In some embodiments, one or more of the most important steps of the method may be performed by such an apparatus.

[0302] In some exemplary embodiments, a programmable logic device (such as a field programmable gate array) may be used to perform part or all of the functions of the methods described herein. In some exemplary embodiments, the field programmable gate array may operate with a microprocessor to perform one of the methods described herein. Typically, the method is preferably performed by some hardware device.

[0303] The description of the present disclosure is merely exemplary in nature, and therefore, changes that do not depart from the essence of the present disclosure are intended to fall within the scope of the present disclosure. Such changes should not be considered to be out of the spirit and scope of the present disclosure. Therefore, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made without departing from the spirit and scope defined by the following claims.

Claims

1. A method of a first terminal, comprising: Receiving a physical sidelink shared channel (PSSCH) from a second terminal via a subchannel in time slot n; Determine, based on the time slot n and the index of the subchannel, a set of physical resource blocks (PRBs) for transmitting a physical sidelink feedback channel (PSFCH) for the PSSCH; Identify a PRB from the PRB set for transmitting the PSFCH; Identifying a time slot configured for transmitting the PSFCH after K time slots from the time slot n; as well as The PSFCH is transmitted in the identified time slot using the identified PRB.

2. The method according to claim 1, wherein: In identifying a time slot configured for sending the PSFCH after K time slots starting from the time slot n, the first terminal identifies the time slot configured for sending the PSFCH according to a PRB index determined based on at least one of the following: an index of the subchannel configured for the PSSCH, the time slot n, the K time slots, an identifier (ID) of the first terminal, an ID of the second terminal, or a code q, wherein the code q represents a cyclic shift or a cyclic shift pair, and q is a positive real number.

3. The method according to claim 1, further comprising: Before transmitting the PSFCH using the identified PRB in the identified time slot, Identifying a transmission mode of the PSSCH; as well as In response to identifying that the transmission mode is a unicast mode, identifying a hybrid automatic repeat request (HARQ) feedback state, The PSFCH is sent when the HARQ feedback state is in an enabled state.

4. The method according to claim 1, further comprising: Before transmitting the PSFCH using the identified PRB in the identified time slot, Identifying a transmission mode of the PSSCH; as well as In response to identifying that the transmission mode is a multicast or broadcast mode, identifying a HARQ feedback state, The PSFCH is sent based on a negative acknowledgement (NACK)-only scheme when the HARQ feedback state is in an enabled state.

5. A method of a first terminal, comprising: receiving a physical sidelink shared channel (PSSCH) from a second terminal; generating a PRB set having a unit physical sidelink feedback channel (PSFCH) resource, each unit PSFCH resource including a combination of a PRB and a cyclic shift; Based on the index of the subchannel through which the PSSCH is received, configuring a candidate PSFCH set using a predetermined number of PRB sets in the PRB set; Determine an index of a unit PSFCH resource for sending a PSFCH from the candidate PSFCH set; as well as The PSFCH is sent to the second terminal using the unit PSFCH resource corresponding to the determined index of the unit PSFCH resource.

6. The method according to claim 5, wherein: Generating a PRB set having unit PSFCH resources each including a PRB and a cyclic shift includes generating the PRB set based on at least one of the following: a transmission period of a PSFCH transmission timing resource (PSFCH TRP), a PSFCH type, a number of PRB sets, a number of cyclic shifts, or a number of repeated transmissions N_C_PSFCH.

7. The method according to claim 6, further comprising: Before generating a PRB set having a unit PSFCH resource each including a PRB and a cyclic shift, receiving, from the base station, information about the transmission period of the PSFCH TRP; receiving information about the PSFCH type from the base station; receiving, from the base station, information on the number of PRB sets constituting PSFCH resources; as well as Information on the number of cyclic shifts constituting PSFCH resources is received from the base station.

8. The method according to claim 5, wherein: Determining the index of the unit PSFCH resource used to send the PSFCH from the candidate PSFCH set includes: determining the index of the unit PSFCH resource as a value obtained by performing a modulo operation on the sum of the identifier (ID) of the first terminal and the ID of the second terminal with the size of the candidate PSFCH set as the modulus.

9. The method according to claim 5, further comprising: Defining a PSFCH sequence generation factor according to an index of a cyclic shift pair corresponding to an index of the unit PSFCH resource; as well as Generate a Zadoff-Chu sequence constituting the PSFCH according to the PSFCH sequence generation factor, The first terminal sends the PSFCH including the Zadoff-Chu sequence to the second terminal.

10. The method according to claim 5, wherein: The unit PSFCH resource is a unit interleaved PSFCH resource, each unit interleaved PSFCH resource includes a combination of a PRB and a cyclic shift pair, the PRB set is an interleaved PRB set, the candidate PSFCH set is a candidate interleaved PSFCH set including a predetermined number of interleaved PRB sets, the predetermined number of interleaved PRB sets are respectively mapped to the index of the cyclic shift pair in the interleaved PRB set based on the index of the subchannel through which the PSSCH is received, and the index of the unit PSFCH resource is the index of the unit interleaved PSFCH resource.

11. The method according to claim 10, further comprising: forming PSSCH-PSFCH transmission groups, each PSSCH-PSFCH transmission group comprising a PSFCH time slot and a PSSCH time slot associated with the PSFCH time slot; Mapping each of the PSSCH-PSFCH transmission groups to a PSFCH opportunity slot; Determine an index of a cyclic shift pair for sending the PSFCH based on at least one of an ID of the first terminal, an ID of the second terminal, or an index of the PSSCH-PSFCH transmission group; as well as Based on the index of the determined cyclic shift pair, an index of a unit interlace PSFCH resource in the candidate interlace PSFCH resources for sending the PSFCH is determined.

12. The method according to claim 10, wherein: When the LBT process needs to be performed for the transmission of the PSFCH and the LBT process is successful, the first terminal sends the PSFCH to the second terminal.

13. The method according to claim 10, wherein: When the first terminal receives a non-transmission indication for PSFCH transmission, the first terminal does not send the PSFCH to the second terminal.

14. A first terminal, comprising a processor, in, The processor causes the first terminal to execute: receiving a physical sidelink shared channel (PSSCH) from a second terminal; generating a PRB set having a unit physical sidelink feedback channel (PSFCH) resource, each unit PSFCH resource including a combination of a PRB and a cyclic shift; Based on the index of the subchannel through which the PSSCH is received, configuring a candidate PSFCH set using a predetermined number of PRB sets in the PRB set; Determine an index of a unit PSFCH resource for sending a PSFCH from the candidate PSFCH set; as well as The PSFCH is sent to the second terminal using the unit PSFCH resource corresponding to the determined index of the unit PSFCH resource.

15. The first terminal according to claim 14, wherein: When generating a PRB set having unit PSFCH resources each including a combination of PRBs and cyclic shifts, the processor also causes the first terminal to generate the PRB set based on at least one of the following: a transmission period of a PSFCH transmission timing resource (PSFCH TRP), a PSFCH type, the number of PRB sets, the number of cyclic shifts, or the number of repeated transmissions N_C_PSFCH.

16. The first terminal according to claim 14, wherein: Before generating a PRB set having unit PSFCH resources each including a PRB and a cyclic shift, the processor further causes the first terminal to execute: receiving, from the base station, information about the transmission period of the PSFCH TRP; receiving information about the PSFCH type from the base station; receiving, from the base station, information on the number of PRB sets constituting PSFCH resources; as well as Information on the number of cyclic shifts constituting PSFCH resources is received from the base station.

17. The first terminal according to claim 14, wherein: In determining the index of the unit PSFCH resource used to send the PSFCH from the candidate PSFCH set, the processor also causes the first terminal to execute: determining the index of the unit PSFCH resource as a value obtained by performing a modulo operation on the sum of the identifier (ID) of the first terminal and the ID of the second terminal with the size of the candidate PSFCH set as the modulus.

18. The first terminal according to claim 14, wherein: The processor further causes the first terminal to execute: defining a PSFCH sequence generation factor according to an index of a cyclic shift pair corresponding to an index of the unit PSFCH resource; and Generate a Zadoff-Chu sequence constituting the PSFCH according to the PSFCH sequence generation factor, The first terminal sends the PSFCH including the Zadoff-Chu sequence to the second terminal.

19. The first terminal according to claim 14, wherein: The unit PSFCH resource is a unit interleaved PSFCH resource, each unit interleaved PSFCH resource includes a combination of a PRB and a cyclic shift pair, the PRB set is an interleaved PRB set, the candidate PSFCH set is a candidate interleaved PSFCH set including a predetermined number of interleaved PRB sets, the predetermined number of interleaved PRB sets are respectively mapped to the index of the cyclic shift pairs in the interleaved PRB set based on the index of the subchannel through which the PSSCH is received, and the index of the unit PSFCH resource is the index of the unit interleaved PSFCH resource.

20. The first terminal according to claim 19, wherein: The processor further causes the first terminal to execute: forming PSSCH-PSFCH transmission groups, each PSSCH-PSFCH transmission group comprising a PSFCH time slot and a PSSCH time slot associated with the PSFCH time slot; Mapping each of the PSSCH-PSFCH transmission groups to a PSFCH opportunity slot; Determine an index of a cyclic shift pair for sending the PSFCH based on at least one of an ID of the first terminal, an ID of the second terminal, or an index of the PSSCH-PSFCH transmission group; as well as Based on the determined index of the cyclic shift pair, an index of a unit interlace PSFCH resource in the candidate interlace PSFCH resources for sending the PSFCH is determined.

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