Terminal and communication method

Abstract

A terminal is provided with: a reception unit that, in an unlicensed band, performs listen before talk (LBT) immediately before a first symbol candidate for which transmission is started or a second symbol candidate for which transmission is started; a control unit that sets parameters for transmission starting from the first symbol candidate and transmission starting from the second symbol candidate, respectively; and a transmission unit that, when the LBT succeeds, applies the parameter corresponding to the symbol candidate that has started transmission from the symbol candidate that has started transmission immediately after the LBT, and starts transmission to another terminal.

Description

Technical Field

[0001] The present invention relates to a terminal and a communication method in a wireless communication system. Background Art

[0002] In LTE (Long Term Evolution) and its successor systems (e.g., LTE-A (LTE Advanced), NR (New Radio) (also known as 5G)), D2D (Device to Device) technology is being studied, in which terminals communicate directly with each other without going through a base station (e.g., non-patent document 1).

[0003] D2D reduces the traffic volume between terminals and base stations, enabling communication between terminals even when base stations are unable to communicate, such as during disasters. Furthermore, 3GPP (registered trademark) (3rd Generation Partnership Project) refers to D2D as "sidelink," but this specification uses the more general term D2D. However, in the description of the following embodiments, sidelink will also be used as needed.

[0004] D2D communication is broadly divided into D2D discovery (also called D2D discovery) for discovering other terminals with which it can communicate, and D2D communication (also called D2D direct communication, D2D communication, direct communication between terminals, etc.) for communicating directly between terminals. Hereinafter, when no special distinction is made between D2D communication, D2D discovery, etc., it is referred to as D2D for short. In addition, the signal sent and received via D2D is referred to as a D2D signal. Various use cases for services related to V2X (Vehicle to Everything) in NR are being studied (e.g., Non-Patent Document 2).

[0005] In addition, NR Release 17 (e.g., Non-Patent Document 3) is studying the use of higher frequency bands than previous releases. For example, the study examined applicable parameter sets including subcarrier spacing and channel bandwidth in the 52.6 GHz to 71 GHz frequency band, physical layer design, and assumed failures in actual wireless communications.

[0006] Prior art literature

[0007] Non-patent literature

[0008] Non-Patent Document 1: 3GPP TS 38.211 V17.4.0 (December 2022)

[0009] Non-Patent Document 2: 3GPP TR 22.886 V16.2.0 (December 2018)

[0010] Non-Patent Document 3: 3GPP TS 38.306 V17.3.0 (December 2022)

[0011] Non-Patent Document 4: 3GPP TS 37.213 V17.4.0 (December 2022)

[0012] Non-Patent Document 5: 3GPP TS 38.214 V17.4.0 (2022-12) Summary of the Invention

[0013] Problems to be solved by the invention

[0014] Unlicensed bands are defined within newly operational frequency bands that utilize higher frequencies than previously possible. Various regulations are defined within unlicensed bands, such as the implementation of LBT (Listen Before Talk) during channel access. To improve resource efficiency, for inter-device direct communication, two symbol candidates for starting transmission in a single time slot are supported. However, when there are two symbol candidates for starting transmission, it is assumed that the optimal parameters for the transmission differ for each candidate.

[0015] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to determine optimal parameters to be applied to transmission of inter-UE direct communication in an unlicensed band.

[0016] Means for solving problems

[0017] According to the disclosed technology, a terminal is provided, comprising: a receiving unit that performs LBT (Listen before talk) in an unlicensed band immediately before a first codeword candidate to be sent or a second codeword candidate to be sent; a control unit that sets parameters for transmission starting from the first codeword candidate and transmission starting from the second codeword candidate; and a transmitting unit that, if the LBT is successful, applies the parameters corresponding to the codeword candidate to be sent starting from the codeword candidate to be sent immediately after the LBT and starts transmission to other terminals.

[0018] Effects of the Invention

[0019] According to the disclosed technology, it is possible to determine preferred parameters to be applied to transmission of inter-UE direct communication in an unlicensed band. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram used to explain V2X.

[0021] Figure 2 This is a timing diagram showing an operation example (1) of V2X.

[0022] Figure 3 This is a timing diagram showing an operation example (2) of V2X.

[0023] Figure 4 This is a timing diagram showing an operation example (3) of V2X.

[0024] Figure 5 This is a timing diagram showing an operation example (4) of V2X.

[0025] Figure 6 is a diagram showing an example of a monitoring operation.

[0026] Figure 7 This is a flowchart for explaining an example of a preemption operation.

[0027] Figure 8 is a diagram illustrating an example of a preemption action.

[0028] Figure 9 FIG. 1 is a diagram illustrating an example of a partial sensing operation.

[0029] Figure 10 : is a diagram for explaining an example of periodic partial monitoring.

[0030] Figure 11 is a diagram for explaining an example of continuous partial monitoring.

[0031] Figure 12 This is a diagram showing an example of the frequency range in the embodiment of the present invention.

[0032] Figure 13 This is a diagram for explaining example (1) of LBT.

[0033] Figure 14 This is a diagram for explaining example (2) of LBT.

[0034] Figure 15 This is a diagram for explaining example (3) of LBT.

[0035] Figure 16 This is a diagram for explaining example (1) of broadband operation.

[0036] Figure 17 This is a diagram for explaining example (2) of broadband operation.

[0037] Figure 18This is a diagram for explaining example (3) of broadband operation.

[0038] Figure 19 This is a diagram for explaining example (4) of broadband operation.

[0039] Figure 20 This is a diagram for explaining example (1) of transmission in an embodiment of the present invention.

[0040] Figure 21 This is a diagram for explaining example (2) of transmission in an embodiment of the present invention.

[0041] Figure 22 This is a diagram for explaining example (3) of transmission in an embodiment of the present invention.

[0042] Figure 23 This is a diagram for explaining example (4) of transmission in an embodiment of the present invention.

[0043] Figure 24 This is a diagram for explaining example (5) of transmission in an embodiment of the present invention.

[0044] Figure 25 This is a diagram showing an example of the functional configuration of the base station 10 in the embodiment of the present invention.

[0045] Figure 26 This is a diagram showing an example of the functional configuration of the terminal 20 in the embodiment of the present invention.

[0046] Figure 27 This is a diagram showing an example of the hardware configuration of the base station 10 or the terminal 20 in the embodiment of the present invention.

[0047] Figure 28 1 is a diagram showing an example of the structure of a vehicle 2001 in the embodiment of the present invention. DETAILED DESCRIPTION

[0048] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0049] In the operation of the wireless communication system according to the embodiments of the present invention, existing technologies are appropriately used. Examples of such existing technologies include, but are not limited to, existing LTE. Furthermore, unless otherwise specified, the term "LTE" used in this specification has a broad meaning that includes LTE-Advanced and subsequent technologies (e.g., NR) or wireless LANs (Local Area Networks).

[0050] Furthermore, in the embodiment of the present invention, the duplexing method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or another method (eg, Flexible Duplex, etc.).

[0051] Furthermore, in the embodiment of the present invention, “configuring” wireless parameters and the like may be pre-configuring predetermined values, or may be configuring wireless parameters notified from the base station 10 or the terminal 20 .

[0052] Figure 1 This figure is used to illustrate V2X. 3GPP is studying the implementation of V2X (Vehicle to Everything) or eV2X (enhanced V2X) by extending D2D functions and is promoting standardization. Figure 1 As shown, V2X is a part of ITS (Intelligent Transport Systems), and is a general term for V2V (Vehicle to Vehicle) which represents the communication between vehicles, V2I (Vehicle to Infrastructure) which represents the communication between vehicles and roadside units (RSU) installed next to the road, V2N (Vehicle to Network) which represents the communication between vehicles and ITS servers, and V2P (Vehicle to Pedestrian) which represents the communication between vehicles and mobile terminals held by pedestrians.

[0053] Furthermore, 3GPP is researching V2X, which uses cellular communications and device-to-device communications using LTE or NR. V2X using cellular communications is also referred to as cellular V2X. Research is progressing on achieving high capacity, low latency, high reliability, and QoS (Quality of Service) control in NR-based V2X.

[0054] Regarding LTE and NR V2X, research is envisioned to continue beyond 3GPP specifications. For example, research is envisioned to address interoperability, lowering the cost of higher-layer implementations, multi-RAT (Radio Access Technology) integration and switching methods, regulatory support in various countries, and data acquisition, distribution, database management, and usage methods for LTE and NR V2X platforms.

[0055] In the embodiments of the present invention, the communication device is primarily envisioned as being mounted on a vehicle, but the embodiments of the present invention are not limited to this form. For example, the communication device can be a terminal held by a person, a device mounted on a drone or aircraft, a base station, an RSU, a relay node, a terminal with scheduling capabilities, etc.

[0056] In addition, SL (Sidelink) can also be distinguished by UL (Uplink) or DL ​​(Downlink) and any one or a combination of the following 1) to 4). In addition, SL can also be other names.

[0057] 1) Time Domain Resource Allocation

[0058] 2) Frequency Domain Resource Allocation

[0059] 3) Reference synchronization signal (including SLSS (Sidelink Synchronization Signal))

[0060] 4) Reference signal for path loss measurement for transmit power control

[0061] In addition, for OFDM (Orthogonal Frequency Division Multiplexing) of SL or UL, any one of CP-OFDM (Cyclic-Prefix OFDM), DFT-S-OFDM (Discrete Fourier Transform-Spread-OFDM), OFDM without transform precoding, and OFDM with transform precoding can also be applied.

[0062] LTE's SL specifies Mode 3 and Mode 4 for SL resource allocation to terminal 20. In Mode 3, transmission resources are dynamically allocated using DCI (Downlink Control Information) sent from base station 10 to terminal 20. Mode 3 also supports Semi-Persistent Scheduling (SPS). In Mode 4, terminal 20 autonomously selects transmission resources from a resource pool.

[0063] In addition, the time slot in the embodiments of the present invention may be replaced by a symbol, a mini-slot, a subframe, a radio frame, or a TTI (Transmission Time Interval). Furthermore, the cell in the embodiments of the present invention may be replaced by a cell group, a carrier component, a BWP, a resource pool, a resource, a RAT (Radio Access Technology), a system (including a wireless LAN), or the like.

[0064] Furthermore, in the embodiments of the present invention, terminal 20 is not limited to a V2X terminal, but may be any type of terminal that performs D2D communication. For example, terminal 20 may be a user-held terminal such as a smartphone, or an IoT (Internet of Things) device such as a smart meter.

[0065] Furthermore, NR-SL envisions supporting HARQ (Hybrid Automatic Repeat Request) in both unicast and multicast sidelinks. Furthermore, NR-V2X defines SFCI (Sidelink Feedback Control Information) that includes HARQ responses. Furthermore, research is underway to transmit SFCI via the Physical Sidelink Feedback Channel (PSFCH).

[0066] In addition, the following description assumes that the PSFCH is used for transmitting HARQ-ACK on the sidelink, but this is only an example. For example, HARQ-ACK on the sidelink can be transmitted using the PSCCH, the PSSCH, or other channels.

[0067] For convenience, all information reported by terminal 20 in HARQ will be referred to as HARQ-ACK below. This HARQ-ACK may also be referred to as HARQ-ACK information. Furthermore, more specifically, the codebook used for HARQ-ACK information reported from terminal 20 to base station 10, etc., is referred to as the HARQ-ACK codebook. The HARQ-ACK codebook defines the bit sequence of the HARQ-ACK information. Furthermore, HARQ-ACK allows NACKs to be transmitted in addition to ACKs.

[0068] Figure 2 This is a timing diagram showing an example of V2X operation (1). Figure 2 As shown, the wireless communication system according to the embodiment of the present invention may include a terminal 20A and a terminal 20B. In addition, there are actually multiple user devices, but Figure 2 The terminal 20A and the terminal 20B are shown as examples.

[0069] Hereinafter, when the terminals 20A and 20B are not particularly distinguished, they are simply referred to as "terminal 20" or "user device". Figure 2 In the embodiment, the case where both the terminal 20A and the terminal 20B are within the coverage of the cell is shown as an example, but the operation in the embodiment of the present invention can also be applied to the case where the terminal 20B is outside the coverage.

[0070] As described above, in this embodiment, the terminal 20 is a device mounted on a vehicle, such as an automobile, and has cellular communication functions and sidelink functions as a UE in LTE or NR. The terminal 20 may also be a conventional portable terminal (such as a smartphone). Furthermore, the terminal 20 may also be an RSU. This RSU may be a UE-type RSU (UE type RSU) that has UE functions, or a gNB-type RSU (gNB type RSU) that has base station functions.

[0071] Furthermore, the terminal 20 does not need to be a device having a single housing. For example, even when various sensors are dispersedly arranged in a vehicle, the terminal 20 may be a device including these various sensors.

[0072] Furthermore, the processing of sidelink transmit data by terminal 20 is essentially the same as that of UL transmission in LTE or NR. For example, terminal 20 scrambles and modulates the codewords of transmit data to generate complex-valued symbols, maps these complex-valued symbols (transmit signals) to layer 1 or layer 2, and performs precoding. The precoded complex-valued symbols are then mapped to resource elements to generate a transmit signal (e.g., a complex-valued time-domain SC-FDMA signal), which is then transmitted from each antenna port.

[0073] The base station 10 also has a cellular communication function as a base station in LTE or NR, as well as functions for enabling communication with the terminal 20 in this embodiment (e.g., resource pool configuration, resource allocation, etc.). Furthermore, the base station 10 may also be an RSU (gNB-type RSU).

[0074] In addition, in the wireless communication system according to the embodiment of the present invention, the signal waveform used by the terminal 20 in the SL or UL may be OFDMA, SC-FDMA, or other signal waveforms.

[0075] As a synchronization signal in the SL, the terminal 20 transmits a sidelink synchronization signal block (S-SSB). The S-SSB may include an S-PSS (Sidelink Primary Synchronization Signal), an S-SSS (Sidelink Secondary Synchronization Signal), and a PSBCH (Physical Sidelink Broadcast Channel). The names S-SSB, S-PSS, and S-SSS are examples, and names other than S-SSB, S-PSS, and S-SSS may also be used.

[0076] The terminal 20 transmits an S-SSB to another terminal 20 based on a signal received from the base station 10, a GNSS (Global Navigation Satellite System) signal, or a signal received from another terminal 20. Furthermore, if the terminal 20 cannot transmit an S-SSB based on a signal from any of the base station 10, the GNSS, or other terminals 20, the terminal 20 may transmit an S-SSB determined autonomously to the other terminal 20. Resources that can be used for S-SSBs may be periodic time slots, also referred to as S-SSB opportunities.

[0077] In step S101, terminal 20A autonomously selects resources for use by the PSCCH and PSSCH from a resource selection window with a predetermined duration. The resource selection window can also be set by base station 10 for terminal 20. The predetermined duration of the resource selection window can be determined based on terminal implementation conditions such as processing time or maximum allowable packet delay, or can be pre-defined by a specification. The predetermined duration can also be referred to as an interval in the time domain.

[0078] In steps S102 and S103, the terminal 20A uses the resources autonomously selected in step S101 to transmit SCI (Sidelink Control Information) using the PSCCH and / or PSSCH, and transmits SL data using the PSSCH. For example, the terminal 20A may transmit the PSCCH using frequency resources that are adjacent or non-adjacent to the frequency resources of the PSSCH, in the same time resources as at least a portion of the time resources of the PSSCH.

[0079] Terminal 20B receives the SCI (PSCCH and / or PSSCH) and SL data (PSSCH) transmitted from terminal 20A. The received SCI may include PSFCH resource information for terminal 20B to transmit HARQ-ACK for the received data. Terminal 20A may include autonomously selected resource information in the SCI and transmit it. Furthermore, resources that can be used for PSFCH may be periodic time slots and the last symbol within the time slot (excluding the final symbol), which may also be referred to as PSFCH opportunities.

[0080] In step S104 , the terminal 20B transmits HARQ-ACK for the received data to the terminal 20A using the PSFCH resources specified by the received SCI.

[0081] If the HARQ-ACK received in step S104 indicates a retransmission request, that is, NACK (negative acknowledgement), terminal 20A retransmits PSCCH and PSSCH to terminal 20B in step S105. Terminal 20A can retransmit PSCCH and PSSCH using autonomously selected resources.

[0082] Furthermore, when HARQ control with HARQ feedback is not performed, step S104 and step S105 may not be performed.

[0083] Figure 3 This is a timing diagram showing an example of V2X operation (2). Blind retransmissions may be performed independently of HARQ control for improving the transmission success rate or the reach distance.

[0084] In step S201 , the terminal 20A autonomously selects resources used for the PSCCH and PSSCH from a resource selection window having a predetermined duration. The resource selection window may be set by the base station 10 for the terminal 20 .

[0085] In steps S202 and S203, terminal 20A uses the resources autonomously selected in step S201 to transmit SCI using the PSCCH and / or PSSCH, and transmits SL data using the PSSCH. For example, terminal 20A may transmit the PSCCH using frequency resources adjacent to the frequency resources of the PSSCH in the same time resources as at least a portion of the time resources of the PSSCH.

[0086] In step S204, the terminal 20A retransmits the SCI based on the PSCCH and / or PSSCH and the SL data based on the PSSCH to the terminal 20B using the resources autonomously selected in step S201. The retransmission in step S204 may be performed multiple times.

[0087] In addition, when blind retransmission is not performed, step S204 may not be performed.

[0088] Figure 4 This is a sequence diagram illustrating an example of V2X operation (3). The base station 10 can perform sidelink scheduling. Specifically, the base station 10 can determine the sidelink resources used by the terminal 20 and transmit information indicating the resources to the terminal 20. Furthermore, when HARQ control with HARQ feedback is applied, the base station 10 can transmit information indicating PSFCH resources to the terminal 20.

[0089] In step S301, the base station 10 transmits DCI (Downlink Control Information) to the terminal 20A using the PDCCH, thereby performing SL scheduling. Hereinafter, for convenience of explanation, the DCI for SL scheduling is referred to as SL scheduling DCI.

[0090] Furthermore, the following scenario is envisioned: in step S301, the base station 10 also transmits DCI for DL ​​scheduling (also referred to as DL allocation) to the terminal 20A using the PDCCH. Hereinafter, for convenience of explanation, the DCI for DL ​​scheduling is referred to as DL scheduling DCI. Upon receiving the DL scheduling DCI, the terminal 20A receives DL data using the PDSCH using the resources specified by the DL scheduling DCI.

[0091] In steps S302 and S303, Terminal 20A uses the resources specified by the SL scheduling DCI to transmit SCI (Sidelink Control Information) using the PSCCH and / or PSSCH, and transmits SL data using the PSSCH. Alternatively, the SL scheduling DCI may specify only PSSCH resources. In this case, for example, Terminal 20A may transmit the PSCCH using frequency resources adjacent to those of the PSSCH, within the same time resources as at least a portion of the PSSCH's time resources.

[0092] Terminal 20B receives SCI (PSCCH and / or PSSCH) and SL data (PSSCH) transmitted from terminal 20A. The SCI received on PSCCH and / or PSSCH includes information on PSFCH resources for terminal 20B to transmit HARQ-ACK for the received data.

[0093] The resource information is included in the DL scheduling DCI or SL scheduling DCI sent from base station 10 in step S301. Terminal 20A obtains the resource information from the DL scheduling DCI or SL scheduling DCI and includes it in the SCI. Alternatively, if the DCI sent from base station 10 does not include the resource information, terminal 20A can autonomously include the resource information in the SCI and send it.

[0094] In step S304 , the terminal 20B transmits a HARQ-ACK for the received data to the terminal 20A using the PSFCH resources identified by the received SCI.

[0095] In step S305, the terminal 20A, for example, transmits a HARQ-ACK using the PUCCH (Physical uplink control channel) resources specified by the DL scheduling DCI (or the SL scheduling DCI) at the timing (e.g., timing in time slots) specified by the DL scheduling DCI (or the SL scheduling DCI), and the base station 10 receives the HARQ-ACK. The HARQ-ACK codebook may include the HARQ-ACK received from the terminal 20B or the HARQ-ACK generated based on the unreceived PSFCH, and the HARQ-ACK for the DL data. However, in the case where there is no allocation of DL data, the HARQ-ACK for the DL data is not included. In Rel.16 of NR, the HARQ-ACK codebook does not include the HARQ-ACK for the DL data.

[0096] In addition, when HARQ control accompanied by HARQ feedback is not performed, step S304 and / or step S305 may not be performed.

[0097] Figure 5 This is a timing diagram showing an example of V2X operation (4). As described above, in the side link of NR, HARQ responses are supported to be sent via PSFCH. In addition, the format of PSFCH can use, for example, the same format as PUCCH (Physical Uplink Control Channel) format 0. That is, regarding the format of PSFCH, it can be a sequence-based format in which the PRB (Physical Resource Block) size is 1 and ACK and NACK are identified based on the difference in sequence and / or cyclic shift. The format of PSFCH is not limited to this. The resources of PSFCH can be configured in the codeword at the end of the time slot or multiple codewords at the end. In addition, a period N is set or predefined for the PSFCH resources. The period N can be set or predefined in units of time slots.

[0098] exist Figure 5In the figure, the vertical axis corresponds to the frequency domain, and the horizontal axis corresponds to the time domain. PSCCH can be configured in one codeword at the start of the time slot, or in multiple codewords starting from the start, or in multiple codewords starting from a codeword other than the start. PSFCH can be configured in one codeword at the end of the time slot, or in multiple codewords at the end of the time slot. In addition, the above-mentioned "start of the time slot" and "end of the time slot" can also omit the consideration of the codewords used for AGC (Automatic Gain Control) and the codewords used for transmission / reception switching. That is, for example, in the case where one time slot is composed of 14 codewords, "the start of the time slot" and "the end of the time slot" can also refer to the codewords of the start and end respectively in the 12 codewords other than the start and end codewords. In Figure 5 In the example shown, the resource pool is configured with three subchannels, and two PSFCHs are allocated three slots after the slot in which the PSSCH is allocated. The arrow from the PSSCH to the PSFCH represents an example of the PSFCH being associated with the PSSCH.

[0099] When the HARQ response in NR-V2X multicast is multicast option 2 of sending ACK or NACK, it is necessary to determine the resources used for PSFCH transmission and reception. Figure 5 As shown, in step S401, terminal 20A, which is the transmitting terminal 20, performs multicast via SL-SCH (Sidelink Shared Channel) to terminal 20B, terminal 20C, and terminal 20D, which are the receiving terminals 20. In the next step S402, terminal 20B uses PSFCH#B, terminal 20C uses PSFCH#C, and terminal 20D uses PSFCH#D to send a HARQ response to terminal 20A. Figure 5 As shown in the example, when the number of available PSFCH resources is less than the number of receiving terminals 20 belonging to the group, it is necessary to determine how to allocate the PSFCH resources. Furthermore, the transmitting terminal 20 can also grasp the number of receiving terminals 20 in the multicast. Furthermore, in multicast option 1, only NACK is transmitted as the HARQ response, and ACK is not transmitted.

[0100] Figure 6 FIG is a diagram showing an example of monitoring operation in NR. In resource allocation mode 2, the terminal 20 selects resources for transmission. Figure 6As shown, terminal 20 performs monitoring within the monitoring window within the resource pool. Through monitoring, terminal 20 receives the resource reservation field or resource assignment field contained in the SCI sent from other terminals 20. Based on this field, terminal 20 identifies available resource candidates within the resource selection window within the resource pool. Terminal 20 then randomly selects a resource from the available resource candidates.

[0101] In addition, if Figure 6 As shown, the resource pool may be configured with a period, for example, a period of 10240 milliseconds. Figure 6 Shows the time slot t0 SL To time slot t Tmax-1 SL The resource pool area in each cycle can be set by a bitmap, for example.

[0102] In addition, if Figure 6 As shown, assuming that the transmission trigger in terminal 20 occurs in time slot n, the priority of the transmission is p TX Terminal 20 is in the time slot from time slot n-T0 to time slot nT proc，0 In the monitoring window up to the immediately preceding time slot, for example, it is possible to detect that other terminals 20 are performing priority p RX When SCI is detected in the monitoring window and RSRP (Reference Signal Received Power) exceeds the threshold, the resources in the resource selection window corresponding to the SCI are excluded. In addition, when SCI is detected in the monitoring window and RSRP is less than the threshold, the resources in the resource selection window corresponding to the SCI are not excluded. The threshold can be based on the priority p, for example. TX and priority p RX The threshold value Th set or defined for each resource within the monitoring window pTX，pRX .

[0103] In addition, if Figure 6 The time slot t shown m SL In this way, for example, resources within the resource selection window corresponding to resources within the monitoring window that were not monitored due to transmission are excluded as candidates for resource reservation information.

[0104] like Figure 6As shown, in the resource selection window from time slot n+T1 to time slot n+T2, the resources occupied by other UEs are identified, and the resources after excluding these resources become the available resource candidates. A , then in S A If the resource selection window is less than 20%, the threshold value Th set for each resource in the monitoring window may be set to pTX，pRX The resource identification is performed again by increasing the threshold Th by 3dB. pTX，pRX The resource identification is performed again, thereby increasing the number of resources that are not excluded due to RSRP being less than the threshold, thereby increasing the set of resource candidates S A Become more than 20% of the resource selection window. A If the threshold value Th is less than 20% of the resource selection window, the threshold value Th set for each resource in the monitoring window can be repeatedly set. pTX，pRX Increase by 3dB and perform resource identification again.

[0105] The lower layer of terminal 20 can A Report to the upper layer. The upper layer of terminal 20 can report to S A A random selection is performed to determine the resource to be used. The terminal 20 may use the determined resource to perform sidelink transmission. For example, the upper layer may be a MAC layer, and the lower layer may be a PHY layer or a physical layer.

[0106] In the above Figure 6 , the operation of the transmitting terminal 20 is described, but the receiving terminal 20 may detect data transmission from another terminal 20 based on the result of monitoring or partial monitoring and receive data from the other terminal 20.

[0107] Figure 7 is a flowchart showing an example of preemption in NR. Figure 8 is a diagram showing an example of preemption in NR. In step S501, the terminal 20 performs monitoring in the monitoring window. When the terminal 20 performs power saving operation, the monitoring may be performed for a predetermined limited period. Next, the terminal 20 identifies each resource in the resource selection window based on the monitoring results and determines a set of resource candidates S. A , select the resource to be used in transmission (S502). Next, the terminal 20 selects the resource candidate set S A The resource set (r_0, r_1, ...) to be preempted is selected (S503). The resource set can be notified from the higher layer to the PHY layer as a resource to be preempted.

[0108] In step S504, the terminal 20 Figure 8At the timing of T(r_0)-T3 shown in FIG, each resource in the resource selection window is identified again based on the monitoring results, and a set of resource candidates S is determined. A , and then determine the preemption of resource sets (r_0, r_1, ...) according to the priority. For example, through further monitoring, Figure 8 The r_1 shown is detected as SCI sent from another terminal 20 and is not included in the S A In the case where preemption is valid, if the value prio_RX indicating the priority of the SCI sent from another terminal 20 is lower than the value prio_TX indicating the priority of the transport block sent from the terminal itself, the terminal 20 determines that the resource r_1 is preempted. In addition, the lower the value indicating the priority, the higher the priority. That is, if the value prio_RX indicating the priority of the SCI sent from another terminal 20 is higher than the value prio_TX indicating the priority of the transport block sent from the terminal itself, the terminal 20 does not preempt the resource r_1 from the SCI. A Alternatively, if preemption is enabled only for a specific priority level (for example, if sl-PreemptionEnable is any one of pl1, pl2, ..., pl8), that priority level is set to prio_pre. In this case, if the value prio_RX indicating the priority of the SCI sent from another terminal 20 is lower than prio_pre, and prio_RX is lower than the value prio_TX indicating the priority of the transport block sent from the terminal itself, the terminal 20 determines that resource r_1 is preempted.

[0109] In step S505, if the terminal 20 determines that preemption has occurred in step S504, the terminal 20 notifies the upper layer of the preemption, reselects resources in the upper layer, and ends the preemption check.

[0110] In addition, when re-evaluation is performed instead of the preemption check, the set S of resource candidates is determined in the above step S504. A After that, in S A If the resource set (r_0, r_1, ...) is not included in the resource, the resource is not used and the resource is reselected in the higher layer.

[0111] Figure 9 FIG is a diagram showing an example of partial monitoring operation in LTE. In the case where partial monitoring is set from a high layer in the LTE side link, as shown in FIG. Figure 9 As shown, the terminal 20 selects and sends resources. Figure 9As shown, terminal 20 performs partial monitoring of a portion of the monitoring window in the resource pool, namely, the monitoring target. Through partial monitoring, terminal 20 receives the resource reservation field contained in the SCI sent from other terminals 20 and, based on this field, identifies available resource candidates within the resource selection window within the resource pool. Terminal 20 then randomly selects a resource from the available resource candidates.

[0112] Figure 9 is from subframe t0 SL To subframe t Tmax-1 SL An example of a resource pool. The resource pool can be set to an object area by a bitmap, for example. Figure 9 As shown, it is assumed that the transmission trigger in the terminal 20 occurs in subframe n. Figure 9 As shown, from subframe n+T1 to subframe n+T2, from subframe t y1 SL To subframe t yY SL Y subframes may be set as a resource selection window.

[0113] The terminal 20 can use the subframe t that is Y subframes long. y1-k×Pstep SL To subframe t yY-k×Pstep SL In one or more monitoring targets, it is detected that, for example, another terminal 20 is transmitting. k can be determined by a 10-bit bitmap, for example. Figure 9 , an example is shown in which the 3rd and 6th bits of the bitmap are set to "1" to indicate that partial monitoring is performed. Figure 9 In subframe t y1-6×Pstep SL To subframe t yY-6×Pstep SL And from subframe t y1-3×Pstep SL To subframe t yY-3×Pstep SL As described above, the kth bit of the bitmap may correspond to the y1-k×Pstep SL To subframe t yY-k×Pstep SL In addition, y i Corresponding to the index (1...Y) within the Y subframe.

[0114] In addition, k is set or predefined by a 10-bit bitmap, P step It can be 100ms. However, when SL communication is performed using DL and UL carriers, P stepIt can be set to (U / (D+S+U))*100ms, where U corresponds to the number of UL subframes, D corresponds to the number of DL subframes, and S corresponds to the number of special subframes.

[0115] When SCI is detected at the monitoring target and RSRP exceeds the threshold, resources in the resource selection window corresponding to the resource reservation field of the SCI are excluded. In addition, when SCI is detected at the monitoring target and RSRP is less than the threshold, resources in the resource selection window corresponding to the resource reservation field of the SCI are not excluded. The threshold can be, for example, based on the priority p of the transmitting side. TX and the receiving side priority p RX , the threshold value Th set or defined for each resource within the monitoring target pTX，pRX .

[0116] like Figure 9 As shown, in the resource selection window set as the Y subframe in the interval [n+T1, n+T2], the terminal 20 identifies the resources occupied by other UEs, and the resources after excluding the resources become the available resource candidates. In addition, the Y subframes may also be discontinuous. If the set of available resource candidates is set to S A , then in S A If the resource selection window is less than 20%, the threshold value Th set for each resource of the monitoring target may be set to pTX，pRX Increase by 3dB and perform resource identification again.

[0117] That is, the threshold Th can also be pTX，pRX The resource identification is performed again when the RSRP is increased, thereby increasing the number of resources that are not excluded due to RSRP being less than the threshold. A The RSSI of each resource is added to the set S. B You can also repeat the S A The RSSI contained in the minimum resource is appended to S B The actions in the above table are continued until the set of resource candidates S is obtained. B Until it becomes 20% or more of the resource selection window.

[0118] The lower layer of terminal 20 can report S to the upper layer B The upper layer of terminal 20 can B The terminal 20 can use the determined resources to perform sidelink transmission. In addition, once the resources are secured, the terminal 20 may not use the resources in a predetermined number of times (e.g., C resel resources are used periodically for monitoring.

[0119] In the NR side link, power saving based on random resource selection and partial sensing is being standardized. The terminal 20 to which partial monitoring is applied performs reception and monitoring only in a specific time slot within the monitoring window. That is, the terminal 20 may also perform resource identification by monitoring only limited resources compared to full monitoring, and perform partial monitoring for resource selection from the identified resource set. In addition, the terminal 20 may not exclude resources from the resources within the resource selection window, but may treat the resources within the resource selection window as the identified resource set and perform random selection for resource selection from the identified resource set.

[0120] In addition, at the moment of resource selection, random selection is performed, and the method of using monitoring information during re-evaluation or preemption checking can be treated as partial monitoring or as random selection.

[0121] Furthermore, as actions in monitoring, the following 1) and 2) may also be applied. Furthermore, sensing and monitoring may be interchangeable, and the actions may include at least one of measurement of received RSRP, acquisition of reserved resource information, and acquisition of priority information.

[0122] 1) Periodic-based partial sensing

[0123] In the mechanism that monitors only a portion of time slots, the action of monitoring time slots is determined based on the reservation periodicity. The reservation period is the value associated with the resource reservation period field. Alternatively, the periodicity can be replaced with periodicity.

[0124] 2) Contiguous partial sensing

[0125] In the mechanism of monitoring only a portion of the time slots, the action of monitoring the time slots is determined based on the aperiodic reservation. In addition, the aperiodic reservation is the value associated with the time resource assignment field.

[0126] Furthermore, multiple resource allocation methods can be set for a resource pool. Furthermore, as a power-saving feature, SL-DRX (Discontinuous Reception) is supported, which means that reception is performed only during a predetermined time interval.

[0127] As described above, partial monitoring is supported as one of the power saving functions. In a resource pool configured with partial monitoring, the terminal 20 can perform the above-described periodic partial monitoring. The terminal 20 can receive information from the base station 10 for configuring a resource pool, wherein the resource pool is configured with partial monitoring and periodic reservation is enabled.

[0128] Figure 10 FIG is a diagram for explaining an example of periodic partial sensing. Figure 10 As shown, Y candidate time slots for resource selection are selected from the resource selection window [n+T1, n+T2].

[0129] You can also use t y SL Let it be a time slot included in Y candidate time slots, and t y-k×Preserve SL Monitor the time slot as the target of periodic partial monitoring.

[0130] P reserve It can correspond to all values ​​included in the set or predefined set sl-ResouceReservePeriodList. Alternatively, it can also be set or predefined to correspond to a subset of P that is limited to sl-ResouceReservePeriodList. reserve The value of P reserve sl-ResouceReservePeriodList and sl-ResouceReservePeriodList can be set for each transmission resource pool in resource allocation mode 2. In addition, as a UE implementation, the periods included in sl-ResouceReservePeriodList other than the limited subset may be monitored. For example, the terminal 20 may additionally monitor the timing corresponding to P_RSVP_Tx.

[0131] Regarding the k value, terminal 20 may monitor the latest monitoring opportunity in a reserved period prior to time slot n of the resource selection trigger, or prior to the start time slot of Y candidate time slots subject to processing time constraints. Furthermore, terminal 20 may additionally monitor periodic monitoring opportunities corresponding to a set of one or more k values. For example, the k value may be set to a value corresponding to the latest monitoring opportunity in a reserved period prior to time slot n of the resource selection trigger, or prior to the start time slot of Y candidate time slots subject to processing time constraints, and a value corresponding to the monitoring opportunity immediately preceding the latest monitoring opportunity in that reserved period.

[0132] As described above, partial monitoring is supported as one of the power saving functions. In a resource pool configured with partial monitoring, the terminal 20 can perform the above-described continuous partial monitoring. The terminal 20 can receive information from the base station 10 for configuring a resource pool, wherein the resource pool is configured with partial monitoring and aperiodic reservation is enabled.

[0133] Figure 11 is a diagram for explaining an example of continuous partial monitoring. Figure 11 As shown, when the trigger for resource selection is time slot n, the terminal 20 selects Y candidate time slots for resource selection from the resource selection window [n+T1, n+T2]. Figure 11 This is an example of the case where Y=7. Figure 11 As shown, the start of Y candidate time slots is recorded as time slot t y1 , and record the next time slot as t y2 , ..., the end of the Y candidate time slots is recorded as time slot t yY .

[0134] Terminal 20 is in the interval [n+T A , n+T B ] to monitor, at n+T B or n+T B Later (set to n+T C ) performs resource selection. In addition, the above periodic partial monitoring can also be performed additionally. In addition, the interval [n+T A , n+T B ]T A and T B It can be any value. In addition, n can also be replaced by the index of any time slot among the Y candidate time slots.

[0135] In addition, the symbol [ can be replaced by the symbol (, and the symbol] can be replaced by the symbol. In addition, for example, the interval [a, b] is the interval from time slot a to time slot b, including time slot a and time slot b. For example, the interval (a, b) is the interval from time slot a to time slot b, excluding time slot a and time slot b.

[0136] Furthermore, although the candidate resources to be selected as the resource are described as Y candidate time slots, all time slots in the interval [n+T1, n+T2] may be candidate time slots or a portion of the time slots may be candidate time slots.

[0137] In addition, as a method for improving reliability and delay performance, inter-terminal coordination is being standardized. For example, inter-terminal coordination method 1 and inter-terminal coordination method 2 shown below are being standardized. Hereinafter, terminal 20 that sends coordination information is referred to as UE-A, and terminal 20 that receives coordination information is referred to as UE-B.

[0138] Inter-UE coordination scheme 1) For UE-B's transmission, UE-A sends a recommended resource set and / or a non-preferred resource set to UE-B. Hereinafter, inter-UE coordination scheme 1 is also referred to as IUC scheme 1 (Inter-UE coordination scheme 1).

[0139] Inter-UE coordination scheme 2: UE-A sends information to UE-B indicating resources indicated by the SCI received from UE-B where conflicts with other transmissions or receptions are expected and / or detected. This information may also be sent via the PSFCH. Hereinafter, inter-UE coordination scheme 2 is also referred to as IUC scheme 2 (Inter-UE coordination scheme 2).

[0140] Regarding the side link of 3GPP Release 16 or Release 17, standardization is being carried out targeting the following 1) and 2).

[0141] 1) In an environment where only 3GPP terminals exist in the ITS (Intelligent Transport Systems) frequency band

[0142] 2) Environments where UL resources can be used for SL in the authorized bands of FR1 (Frequency Range 1) and FR2 defined in NR

[0143] As sidelinks in 3GPP Release 18 and later, unlicensed bands are being studied as new targets, such as the 5 GHz-7 GHz band and the 60 GHz band.

[0144] Figure 12 This is a diagram showing an example of frequency bands used in wireless communication systems. In the NR specifications of 3GPP Release 15 and Release 16, the use of frequency bands above 52.6 GHz is studied. Figure 12 As shown, FR (Frequency Range) 1 currently specified for operation is a frequency band from 410 MHz to 7.125 GHz, SCS (Sub Carrier Spacing) is 15, 30, or 60 kHz, and bandwidth is from 5 MHz to 100 MHz.

[0145] FR2-1 is the frequency band from 24.25GHz to 52.6GHz, SCS uses 60, 120 or 240kHz, and the bandwidth is from 50MHz to 400MHz. Figure 12 As shown, FR2-2 can support 52.6 GHz to 71 GHz, and can also support frequency bands exceeding 71 GHz.

[0146] When using a band exceeding 52.6 GHz, cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) / discrete Fourier transform-spread (DFT-S-OFDM) with a larger sub-carrier spacing (SCS) can also be applied.

[0147] Furthermore, in high-frequency bands such as FR2-2, increased inter-carrier phase noise becomes a problem, and therefore, a larger (wider) SCS or single-carrier waveform may need to be applied.

[0148] For example, as examples of unlicensed bands in the 5 GHz-7 GHz frequency band, 5.15 GHz to 5.35 GHz, 5.47 GHz to 5.725 GHz, and 5.925 GHz and above are conceivable.

[0149] For example, as examples of unlicensed bands in the 60 GHz band, 59 GHz to 66 GHz, 57 GHz to 64 GHz, or 66 GHz, 59.4 GHz to 62.9 GHz, etc. can be envisioned.

[0150] In the unlicensed band, various rules are set to avoid affecting other systems or other devices.

[0151] For example, in the 5GHz-7GHz band, LBT (Listen before talk) is performed during channel access. The base station 10 or terminal 20 performs a power check during a predetermined period immediately before transmission. If the power exceeds a certain value, i.e., if another device's transmission is detected, transmission is terminated (also known as LBT failure). Furthermore, a maximum channel occupancy time (MCOT) is specified. The MCOT is the maximum time interval allowed for continued transmission after LBT, for example, 4ms in Japan.

[0152] Furthermore, the Occupied Channel Bandwidth (OCB) requirement states that when transmitting within a certain carrier bandwidth, at least X% of that bandwidth must be used. For example, in Europe, 80% to 100% of the Nominal Channel Bandwidth (NCB) is required. The purpose of the OCB requirement is to ensure accurate power detection for channel access.

[0153] Furthermore, regarding maximum transmit power and maximum power spectral density, regulations stipulate that transmission must be performed below a predetermined transmit power level to avoid excessive interference. For example, in Europe, the maximum transmit power in the 5150 MHz to 5350 MHz band is 23 dBm. Furthermore, in Europe, the maximum power spectral density in the 5150 MHz to 5350 MHz band is 10 dBm / MHz.

[0154] For example, in the 60 GHz band, LBT is performed during channel access. The base station 10 or terminal 20 performs power detection during a predetermined period immediately before transmission. If the power exceeds a certain value, i.e., if another device is detected transmitting, transmission is suspended. Furthermore, regarding the maximum transmit power and maximum power spectral density, transmission is limited to a predetermined transmit power or less. Furthermore, the ability to meet OCB requirements is specified.

[0155] In NR, based on the differences in the time-direction behavior of LBT (the period of monitoring), the following four types of channel access procedures are specified. In addition, this monitoring is different from the above-mentioned sidelink monitoring and is described as LBT monitoring (LBT Sensing) for the sake of distinction.

[0156] Type 1) performs variable-time LBT monitoring before transmission. Also known as Category 4 LBT.

[0157] Type 2A) performs a 25μs LBT check before transmission. Also known as Category 2 LBT.

[0158] Type 2B) performs a 16μs LBT check before transmission. Also known as Category 2 LBT.

[0159] Type 2C) Starts transmission without LBT. Same as sending in the authorized band.

[0160] Figure 13 This is a diagram for explaining example (1) of LBT. Figure 13 This is an example of a channel access procedure of Type 1. Type 1 is further classified into four levels representing channel access priority classes (CAPC) based on differences in LBT monitoring lengths. LBT monitoring is performed in the following two periods.

[0161] The first period is the prioritization period or deferment period, which has 16+9×m p Length [μs]. m p A fixed value is specified for each channel access priority level.

[0162] The second period is the backoff process, which has a length of 9 × N [μs]. The value of N is randomly determined from a certain range (see the CWS adjustment process in Non-Patent Document 4). N is the initial value of the backoff counter. If the power of the signal from another device is not detected during the 9 [μs] period, the backoff counter value is decremented by 1.

[0163] In the above description, the LBT monitoring period of 9 μs may also be referred to as an LBT monitoring time slot period.

[0164] exist Figure 13 In the example, m p =3, the retention period is 43μs. Figure 13 As shown in , the backoff counter is fixed when the channel is busy. Figure 13 As shown, when an error is detected due to a transmission conflict between the NR-U gNB and the wireless LAN node #2, the contention window size (CWS) in the NR-U gNB is expanded from 3 to 13.

[0165] Figure 14 This is a diagram for explaining example (2) of LBT. Figure 14This is an example of a channel access procedure of Type 2A or Type 2B without random backoff. Type 2A sets a power detection gap of 25 μs or longer before transmission, and Type 2B sets a power detection gap of 16 μs before transmission.

[0166] Figure 15 This is a diagram for explaining example (3) of LBT. Figure 15 This is an example of a Type 2C channel access procedure. Figure 15 As shown, no power detection is performed before transmission, and transmission is performed immediately after a gap of no more than 16μs. The maximum transmission period can be 584μs.

[0167] As mentioned above, multiple LBT types are supported in NR-U (Unlicensed). In the above type 1, the initial value N of the backoff counter is set to CW ranging from 0 to a value determined based on the channel access priority level p. p Table 1 shows the m specified for each channel access priority level p in UL. p 、CW p Minimum CW p，min 、CW p Maximum CW p，max example.

[0168] [Table 1]

[0169] Level p <![CDATA[m p ]]> <![CDATA[CW min,p ]]> <![CDATA[CW max,p ]]> 1 2 3 7 2 2 7 15 3 3 15 1023 4 7 15 1023

[0170] As shown in Table 1, m is determined according to the channel access priority level p. p 、CW p，min 、CW p，max . When p is 1, if the LBT period is calculated according to Table 1, the minimum is 34μs and the maximum is 88μs. When p is 2, if the LBT period is calculated according to Table 1, the minimum is 34μs and the maximum is 160μs. When p is 3, if the LBT period is calculated according to Table 1, the minimum is 43μs and the maximum is 9286μs. When p is 4, if the LBT period is calculated according to Table 1, the minimum is 79μs and the maximum is 9286μs. In addition, Table 1 is a table for UL.

[0171] The LBT type and channel access priority level may be determined based on notification from the base station 10, channel type, etc. The 25 μs or 16 μs gap may be set by scheduling of the base station 10, taking into account TA (Timing Advance) and CP extension.

[0172] LBT applied to channel access is performed according to each predetermined bandwidth (for example, 20MHz). The predetermined bandwidth can be called an LBT channel, or an RB set (Resource Block set), or an LBT frequency band, but is not limited thereto. Transmission can be performed when no power is detected in the LBT channel containing each transmission. On the other hand, each CC in Uu can be defined by a bandwidth wider than the LBT channel. That is, wideband operation is supported. In addition, Uu is a wireless interface between UTRAN (Universal Terrestrial Radio Access Network) and UE (User Equipment).

[0173] Figure 16 This is a diagram for explaining example (1) of broadband operation. Figure 17 This is a diagram for explaining example (2) of broadband domain operation. When broadband domain is used in unlicensed band, as shown in FIG. Figure 16 or Figure 17 As shown, when LBT in the gNB succeeds in part or all of the LBT channels, transmission can be allowed in the LBT channels where LBT succeeds. Figure 16 As shown, the gNB can transmit a single continuous block, such as Figure 17 As shown, the gNB can also send multiple discontinuous blocks.

[0174] Regarding DL in the unlicensed band, DL Type A, which performs LBT on each channel, and DL Type B, which performs LBT Type 1 on a randomly selected channel and LBT Type 2A on the remaining channels, are specified.

[0175] DL Type A is further classified into Type A1 and Type A2. In Type A1, the contention window CWp is determined for each channel. In Type A2, the maximum CWp among the CWps determined for each channel is used.

[0176] DL Type B is further classified into Type B1 and Type B2. In Type B1, a single CWp is applied to all channels. In Type B2, the maximum CWp among the CWps determined for each channel is used.

[0177] If LBT is successful on some or all LBT channels in the gNB, PDSCH transmission is allowed on the LBT channels where LBT was successful. The gNB can transmit a single block that is continuous in the frequency direction, or it can transmit multiple blocks that are discontinuous in the frequency direction.

[0178] Figure 18 This is a diagram for explaining example (3) of broadband operation. Figure 19 This is a diagram for explaining Example (4) of broadband domain application. Figure 18 or Figure 19 As shown, when LBT in the UE succeeds in all LBT channels in the scheduled band, transmission may be allowed. Figure 19 As shown, in the case where LBT fails in a part of the LBT channels, transmission may not be allowed.

[0179] Figure 20 This is a diagram for explaining example (1) of transmission in an embodiment of the present invention. Figure 20 As shown, for PSCCH / PSSCH transmission, two start symbol candidates are supported in one slot. PSCCH / PSSCH can also be replaced with PSCCH and / or PSSCH.

[0180] When a PSCCH / PSSCH is transmitted in time slot n, LBT may fail, preventing the start of transmission from the first start symbol X. On the other hand, LBT may succeed in the second start symbol Y midway through time slot n. Transmission of the PSCCH / PSSCH from the second start symbol Y can improve resource utilization efficiency. When transmission starts from the second start symbol Y, a portion of the PSSCH is not transmitted.

[0181] In addition, LBT can be performed immediately before the first start symbol candidate X, or immediately before the second start symbol candidate Y. If LBT is successful immediately before the first start symbol candidate X, terminal 20 can transmit from the first start symbol candidate X. If LBT is successful immediately before the second start symbol candidate Y, terminal 20 can transmit from the second start symbol candidate Y.

[0182] The details of the operation when two start symbol candidates are available need to be determined. For example, when two start symbol candidates can be used, various parameters associated with the SL need to be appropriately determined. For example, it is necessary to determine how to use the PSFCH overhead indication field and N in the first stage SCI defined for TBS (Transport Block Size) determination. symb PSFCH In addition, the TBS is determined based on a set or pre-set PSCCH / PSSCH symbol reference number. For example, it is necessary to determine a method for selecting a start symbol when transmitting across multiple RB sets.

[0183] In addition, regarding TBS determination, the following operation may be performed (see Non-Patent Document 5).

[0184] In the case where the period of the PSFCH opportunity is 0 or 1, the size of the PSFCH Overhead Notification field can be 0 bits. Since the overhead is always the same, no notification is required.

[0185] When the PSFCH opportunity period exceeds 1 (e.g., period 2 or 4), the PSFCH overhead notification field may be 1 bit in size. Since the overhead differs between slots with and without PSFCH, the use of the PSFCH is notified.

[0186] N symb PSFCH Equivalent to the number of PSFCH overhead symbols per time slot. When the period of PSFCH opportunity is 0, no PSFCH overhead notification via SCI is performed. symb PSFCH When the period of PSFCH opportunity is 1, PSFCH overhead notification via SCI is not performed. symb PSFCH When the PSFCH opportunity period is 2 or 4, the PSFCH overhead notification is 1 when N symb PSFCH When N is 3 and the overhead notification is 0 symb PSFCH is 0.

[0187] Therefore, when two start codeword candidates can be used, or when set or pre-set, at least any one of the following actions 1), 2), and 3) can be applied.

[0188] The SL parameters shown in 1) to 5) below action 1) can be set or pre-set for each of the first start symbol candidate X and the second start symbol candidate Y. Different parameters can also be set or pre-set for the transmission from the first start symbol candidate X and the transmission from the second start symbol candidate Y.

[0189] 1) SL-PSCCH-Config (e.g., sl-TimeResourcePSCCH, sl-FreqResourcePSCCH). SL-PSCCH-Config is a configuration associated with the PSCCH and may include time resources, frequency resources, etc. For example, the time resource of the PSCCH may be 3 symbols for X and 2 symbols for Y.

[0190] 2) SL-PSSCH-Config (e.g., sl-Scaling): SL-PSSCH-Config is a configuration associated with the PSSCH and may include parameters for adjusting the amount of PSSCH resources considered when determining the TBS.

[0191] 3) SL-MinMaxMCSList: SL-MinMaxMCSList may also include parameters that determine the maximum or minimum available MCS.

[0192] 4) sl-PowerControl (e.g., sl-P0-PSSCH-PSCCH): sl-PowerControl may also include parameters for determining the power of SL transmission, etc.

[0193] 5) SL-CSI-RS-Config (e.g., sl-CSI-RS-FirstSymbol). SL-CSI-RS-Config is a configuration for CSI-RS and may include parameters related to determining the symbols to which the CSI-RS is mapped.

[0194] In addition, the SL parameters that are set or pre-set for the first start symbol candidate X and the second start symbol candidate Y are not limited to the parameters shown in 1) to 5) above.

[0195] In addition, any one of the parameters shown in 1) to 5) above may be a parameter common to the first start symbol candidate X and the second start symbol candidate Y.

[0196] In addition, when no parameter is set or pre-set for the second start symbol candidate Y, it can also be applied to the case where one parameter set or pre-set is transmitted from any one of the first start symbol candidate X and the second start symbol candidate Y.

[0197] Through the above-mentioned operation 1), it is possible to set or pre-set optimal parameters for each of the case where transmission starts from the first start symbol candidate and the case where transmission starts from the second start symbol candidate.

[0198] Action 2) For the first stage SCI PSFCH overhead notification field and / or N symb PSFCH Different actions can be performed when two start codeword candidates can be used and when two start codeword candidates cannot be used.

[0199] When two start symbol candidates are available, the following operations a), b), and c) may be performed.

[0200] a) The PSFCH overhead notification field can be always 0 bits regardless of the PSFCH period. symb PSFCH Always set to a constant value. For example, N symb PSFCH It may be set to a defined value (such as 0 or 3), or may be set to a preset value.

[0201] b) The PSFCH overhead notification field can be always 1 bit regardless of the PSFCH period. symb PSFCH The value of is set to K. K can be a defined value (such as 3, etc.) or a set or pre-set value.

[0202] When the PSFCH overhead notification is 0, N symb PSFCH The value of is set to L. L can be a defined value (such as 0, etc.) or a set or pre-set value.

[0203] The PSFCH overhead notification field may be replaced with another field. For example, it may be replaced with a field indicating whether the TBS is calculated using the "number of PSCCH / PSSCH symbols in the time slot with PSFCH" or the "set or pre-set number of PSCCH / PSSCH reference symbols."

[0204] When this field is 1, the TBS can be calculated using the "number of PSCCH / PSSCH symbols in the time slot with PSFCH". The TBS can also be calculated using the number of SL symbols in 1 time slot - 2 - PSFCH overhead (i.e. 3). When this field is 0, the TBS can be calculated using the "number of PSCCH / PSSCH reference symbols set or pre-set". N can also be used. symb PSFCH Set the value of to 0.

[0205] Alternatively, it may be replaced with a field indicating whether to use "the number of PSCCH / PSSCH symbols transmitted from the first starting symbol candidate X in a time slot without PSFCH" or "the number of PSCCH / PSSCH reference symbols set or set in advance" to calculate TBS.

[0206] Furthermore, when there are multiple "numbers of PSCCH / PSSCH reference symbols that are set or pre-set", these may be replaced with a field indicating which one is used to calculate the TBS.

[0207] c) The PSFCH overhead notification field may be set to 0 bit or 1 bit based on the PSFCH period, similar to the prior art.

[0208] For example, N symb PSFCH The value of is always constant. For example, N symb PSFCH The value of is set to a defined value (for example, 0, 3, etc.), or it can be set to a set or pre-set value, or it can be set to the difference between the "number of PSCCH / PSSCH code elements in the time slot with PSFCH" and the "set or pre-set number of PSCCH / PSSCH reference code elements".

[0209] When the PSFCH overhead notification is 1, N symb PSFCH The value of is set to K. K can be a defined value (for example, other than 3) or a set or pre-set value.

[0210] When the PSFCH overhead notification is 0, N symb PSFCH The value of is set to L. L can be a defined value (such as 0, etc.) or a set or pre-set value.

[0211] Action 2) can be limited to apply to time slots without PSFCH, and can also be applied to time slots with PSFCH. symb PSFCH The value of can be subtracted from the "set or pre-set number of PSCCH / PSSCH reference code symbols" or may not be included in the "set or pre-set number of PSCCH / PSSCH reference code symbols".

[0212] Through the above-mentioned action 2), when the TBS is determined based on the "set or pre-set number of PSCCH / PSSCH reference symbols", the processing of the PSFCH overhead can be optimized.

[0213] Action 3) When transmission is performed across multiple RB sets, the starting symbol candidate from which transmission of PSCCH / PSSCH across N RB sets is to be started may be determined based on which starting symbol candidate can be used to start transmission in each RB set.

[0214] Whether or not to perform transmission may be determined based on whether or not transmission can be started from each start symbol candidate in all N RB sets.

[0215] Figure 21 This is a diagram for explaining example (2) of transmission in an embodiment of the present invention. Figure 21 As shown, the PSCCH / PSSCH transmission may be performed from X only when transmission can be started from the first start symbol candidate X in all N RB sets (4 in the figure).

[0216] Figure 22 This is a diagram for explaining example (3) of transmission in an embodiment of the present invention. If the first start symbol candidate X cannot be transmitted from at least one of the N RB sets, the PSCCH / PSSCH may not be transmitted from X in all N RB sets.

[0217] like Figure 22 As shown, only when transmission can be performed from the second starting symbol candidate Y in all N RB sets, the PSCCH / PSSCH transmission may be performed from Y. On the other hand, when transmission cannot be performed from the second starting symbol candidate Y in at least one RB set among the N RB sets, the PSCCH / PSSCH transmission may not be performed in all N RB sets in the time slot.

[0218] In addition, not sending may mean discarding the sending or postponing the sending.

[0219] The above-described operation allows transmission of transport blocks to be limited to situations where transmission can be reliably performed, that is, transmissions with a low probability of successful reception can be avoided.

[0220] Furthermore, whether or not to perform transmission may be determined based on whether or not transmission can be started from each start symbol candidate in RB sets of a specific number or more among N RB sets.

[0221] Figure 23 This is a diagram for explaining the example (4) of transmission in the embodiment of the present invention. Figure 23 As shown, when N1 RB sets among N RB sets can be transmitted starting from the first start symbol candidate X, the PSCCH / PSSCH transmission TB can also be transmitted in the N1 RB sets. Figure 23 In the example, N1 = 2. N1 may be set to a value greater than the minimum value N1_min. N1_min may be a defined value or a set or pre-set value.

[0222] Figure 24 This is a diagram for explaining the example (5) of sending in the embodiment of the present invention. Figure 24 As shown, if the number of RB sets that can be transmitted starting from the first start symbol candidate X in N RB sets is less than N1_min, the PSCCH / PSSCH transmission may not be performed from X in all N RB sets. Figure 24 In the example, N1_min is 2 or more.

[0223] like Figure 24As shown, when N2 RB sets in the N RB sets can be transmitted starting from the second starting codeword candidate Y, the PSCCH / PSSCH transmission TB can also be transmitted from the second starting codeword candidate Y in the N2 RB sets. N2 can also be set to a value greater than the minimum value N2_min. Figure 24 In the example, N2 = 3. Transmission may not be performed in the (N-N2) RB set. N2_min may be a defined value or a set or pre-set value. Alternatively, N2_min = N, or transmission may be limited to the case where transmission can be performed in all N RB sets and from Y.

[0224] When the number of RB sets in N RB sets that can be transmitted starting from the second start symbol candidate Y is less than N2_min, the PSCCH / PSSCH transmission may not be performed starting from Y in all N RB sets.

[0225] When the N1 or N2 RB sets are discontinuous RB sets, the above operation can be applied by replacing the maximum number of contiguous RB sets in the discontinuous RB sets with N1 or N2. Alternatively, N1_min<N2_min.

[0226] By performing the above-mentioned operations, available resources can be utilized to the maximum extent possible.

[0227] Furthermore, in the above-described embodiment, the conventional SL channel and SL signal structure is used, but the present invention is not limited thereto. For example, this embodiment can also be applied when an interlaced channel is used as a structure to meet the OCB requirement.

[0228] In addition, the above-mentioned embodiment can also be limited to the case where the predetermined conditions are met. For example, it can also be applied in association with a predetermined SL channel or SL signal. For example, this embodiment can be applied to any one of PSCCH / PSSCH, PSFCH, S-SSB, and SL positioning RS. For example, it can also be applied based on a predetermined setting or a pre-setting. For example, in a resource pool, this embodiment can also be applied when the present embodiment is "validated" through a setting or a pre-setting. For example, when the LBT method involved in the second SL transmission is not type 1 or is no longer type 1, this embodiment may not be applied.

[0229] In addition, in order to apply LBT type 2A, 2B or 2C, additional transmission (additional TX) such as CP extension may be performed immediately before P is transmitted.

[0230] In addition, the applicability of this embodiment and the UE capabilities related to the actions may also be defined, and may be reported to the base station 10 and / or the terminal 20 or not.

[0231] In addition, the SL transmission of the UE can be any one of PSCCH, PSSCH, PSFCH, S-SSB, and SL-PRS, and different channels or signals can also be applied in each action of this embodiment.

[0232] In addition, at least one of the SL transmissions of the UE may be a UL transmission.

[0233] This embodiment can be applied to any one of resource selection, resource reselection, re-evaluation, and preemption verification.

[0234] Furthermore, the method in the embodiment of the present invention is not limited to the above-mentioned inter-terminal direct communication scenario, and can also be applied to other similar scenarios.

[0235] The above embodiments are not limited to application to V2X terminals, but can also be applied to terminals performing D2D communication.

[0236] According to the above-described embodiments, in inter-UE direct communication using one or more RB sets in the unlicensed band, when multiple transmission start symbol candidates are set, optimal parameters can be applied to transmission of each candidate.

[0237] That is, it is possible to determine optimal parameters suitable for transmission of inter-UE direct communication in the unlicensed band.

[0238] (Device Structure)

[0239] Next, the functional configuration examples of the base station 10 and terminal 20 that perform the above-described processing and operations are described. The base station 10 and terminal 20 include functions for implementing the above-described embodiments. However, the base station 10 and terminal 20 may each include only a portion of the functions described in the embodiments.

[0240] <Base Station 10>

[0241] Figure 25 1 is a diagram showing an example of the functional configuration of the base station 10. Figure 25 As shown, the base station 10 includes a transmitting unit 110 , a receiving unit 120 , a setting unit 130 , and a control unit 140 . Figure 25 The functional configuration shown is merely an example, and any functional divisions and names of functional units may be used as long as the operations according to the embodiments of the present invention can be executed.

[0242] The transmitter 110 includes a function for generating a signal to be transmitted to the terminal 20 and wirelessly transmitting the signal. The receiver 120 includes a function for receiving various signals transmitted from the terminal 20 and obtaining, for example, higher-layer information from the received signals. Furthermore, the transmitter 110 includes a function for transmitting the NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL reference signals, and the like to the terminal 20.

[0243] The setting unit 130 stores pre-set setting information and various setting information to be sent to the terminal 20 in a storage device, and reads the setting information from the storage device as needed. The content of the setting information is, for example, information related to the setting of D2D communication.

[0244] As described in the embodiments, the control unit 140 performs processing related to the configuration for the terminal 20 to perform D2D communication. Furthermore, the control unit 140 transmits the schedule for D2D communication and DL communication to the terminal 20 via the transmission unit 110. Furthermore, the control unit 140 receives information related to HARQ responses for D2D communication and DL communication from the terminal 20 via the reception unit 120. Functional units related to signal transmission within the control unit 140 may be included in the transmission unit 110, while functional units related to signal reception within the control unit 140 may be included in the reception unit 120.

[0245] <Terminal 20>

[0246] Figure 26 2 is a diagram showing an example of the functional structure of the terminal 20. Figure 26 As shown, the terminal 20 includes a transmitting unit 210 , a receiving unit 220 , a setting unit 230 , and a control unit 240 . Figure 26 The functional configuration shown is merely an example, and any functional divisions and names of functional units may be used as long as the operations according to the embodiments of the present invention can be executed.

[0247] The transmitting unit 210 generates a transmission signal based on the transmission data and transmits the transmission signal wirelessly. The receiving unit 220 receives various signals wirelessly and obtains higher-layer signals from the received physical layer signals. In addition, the receiving unit 220 has the function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals or reference signals transmitted from the base station 10. For example, as D2D communication, the transmitting unit 210 transmits PSCCH (Physical Sidelink Control Channel), PSSCH (Physical Sidelink Shared Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel), etc. to other terminals 20, and the receiving unit 220 receives PSCCH, PSSCH, PSDCH or PSBCH, etc. from other terminals 20.

[0248] The configuration unit 230 stores various configuration information received by the receiving unit 220 from the base station 10 or the terminal 20 in a storage device and reads it from the storage device as needed. Furthermore, the configuration unit 230 also stores pre-set configuration information. This configuration information may include, for example, information related to D2D communication configuration.

[0249] As described in the embodiment, the control unit 240 controls D2D communication that establishes an RRC connection with another terminal 20. Furthermore, the control unit 240 performs processing related to power saving. Furthermore, the control unit 240 performs processing related to HARQ for D2D communication and DL communication. Furthermore, the control unit 240 transmits information related to HARQ responses for D2D communication and DL communication scheduled from the base station 10 to the other terminal 20. Furthermore, the control unit 240 can also schedule D2D communication for the other terminal 20. Furthermore, based on the results of sidelink monitoring, the control unit 240 can autonomously select resources for D2D communication from a resource selection window, or perform re-evaluation or preemption. Furthermore, the control unit 240 performs processing related to power saving in D2D communication transmission and reception. Furthermore, the control unit 240 performs processing related to inter-terminal coordination in D2D communication. Furthermore, the control unit 240 performs processing related to LBT in D2D communication. The functional units related to signal transmission in the control unit 240 may be included in the transmitting unit 210 , and the functional units related to signal reception in the control unit 240 may be included in the receiving unit 220 .

[0250] (Hardware Structure)

[0251] The block diagram used in the description of the above embodiment ( Figure 25 and Figure 26 ) shows blocks in functional units. These functional blocks (structural parts) are implemented by any combination of at least one of hardware and software. In addition, there is no particular limitation on the implementation method of each functional block. That is, each functional block can be implemented using a device that is physically or logically combined, or it can be implemented using multiple devices by connecting two or more physically or logically separated devices directly or indirectly (for example, using wired or wireless connections). The functional blocks can also be implemented by combining software in the above-mentioned one device or the above-mentioned multiple devices.

[0252] Functions include, but are not limited to, judging, determining, determining, calculating, calculating, processing, deriving, investigating, searching, confirming, receiving, sending, outputting, accessing, resolving, selecting, choosing, establishing, comparing, assuming, expecting, regarding, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assigning. For example, a functional block (structural unit) that enables the transmission function is called a transmitting unit or a transmitter. In short, as described above, there is no particular limitation on the implementation method.

[0253] For example, the base station 10 , the terminal 20 , and the like in one embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 27 This figure shows an example of the hardware configuration of a base station 10 and a terminal 20 according to one embodiment of the present disclosure. The base station 10 and the terminal 20 may be configured as computer devices that physically include a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, and a bus 1007.

[0254] In the following description, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of the base station 10 and the terminal 20 may include one or more of the devices shown in the figures, or may exclude some of the devices.

[0255] The various functions in the base station 10 and the terminal 20 are implemented as follows: predetermined software (programs) are read into hardware such as the processor 1001 and the storage device 1002, so that the processor 1001 performs calculations and controls the communication of the communication device 1004 or controls at least one of the reading and writing of data in the storage device 1002 and the auxiliary storage device 1003.

[0256] Processor 1001 controls the entire computer by, for example, running an operating system. Processor 1001 may also be comprised of a central processing unit (CPU) that includes interfaces with peripheral devices, a control device, a computing device, registers, and the like. For example, control unit 140 and control unit 240 described above may also be implemented by processor 1001.

[0257] In addition, the processor 1001 reads a program (program code), a software module, or data from at least one of the auxiliary storage device 1003 and the communication device 1004 to the storage device 1002, and performs various processes based on the program. As a program, a program that causes the computer to execute at least a part of the operations described in the above embodiments is used. For example, Figure 25 The control unit 140 of the base station 10 shown may also be implemented by a control program stored in the storage device 1002 and executed in the processor 1001. For example, Figure 26 The control unit 240 of the terminal 20 shown can also be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. Although the various processes described above are performed by a single processor 1001, the various processes described above can also be performed simultaneously or sequentially by two or more processors 1001. The processor 1001 can also be implemented by one or more chips. In addition, the program can also be transmitted from the network via a telecommunications line.

[0258] The storage device 1002 is a computer-readable recording medium and may be composed of, for example, at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and RAM (Random Access Memory). The storage device 1002 may also be referred to as a register, cache, or main memory (main storage device). The storage device 1002 can store executable programs (program code), software modules, and the like for implementing the communication method according to one embodiment of the present disclosure.

[0259] The auxiliary storage device 1003 is a computer-readable recording medium, and may be composed of, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a floppy disk, a magneto-optical disk (for example, a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (for example, a card, a stick, a key drive), a Floppy (registered trademark) disk, a magnetic stripe, and the like. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium that includes at least one of the storage device 1002 and the auxiliary storage device 1003.

[0260] Communication device 1004 is hardware (a transceiver) used to facilitate communication between computers via at least one of a wired network and a wireless network. It may also be referred to as a network device, network controller, network card, or communication module. Communication device 1004 may also include, for example, a high-frequency switch, a duplexer, a filter, a frequency synthesizer, and the like to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, transceiver antennas, amplifiers, transceivers, and transmission path interfaces may also be implemented using communication device 1004. The transceiver may also be implemented by physically or logically separating the transmitter and receiver.

[0261] The input device 1005 is an input device that receives input from the outside (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to the outside (e.g., a display, speaker, LED light, etc.). Alternatively, the input device 1005 and the output device 1006 may be integrally formed (e.g., a touch panel).

[0262] Furthermore, the processor 1001, the storage device 1002, and other devices are connected via a bus 1007 for communicating information. The bus 1007 may be configured as a single bus or may be configured as different buses between devices.

[0263] Furthermore, the base station 10 and the terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array), and may implement some or all of the functional blocks using this hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0264] Figure 28 2001 shows a structural example of a vehicle. Figure 28 As shown, vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. The various forms and embodiments described in this disclosure may also be applied to a communication device mounted on vehicle 2001, such as communication module 2013.

[0265] The driving unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also referred to as a steering wheel) and is configured to steer at least one of the front wheels and the rear wheels based on the user's operation of the steering wheel.

[0266] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals from various sensors 2021 to 2029 included in the vehicle 2001 are input to the electronic control unit 2010. The electronic control unit 2010 may also be referred to as an ECU (Electronic Control Unit).

[0267] As signals from various sensors 2021 to 2029, there are current signals from the current sensor 2021 that monitors the current of the motor, speed signals of the front and rear wheels obtained by the speed sensor 2022, air pressure signals of the front and rear wheels obtained by the air pressure sensor 2023, vehicle speed signals obtained by the vehicle speed sensor 2024, acceleration signals obtained by the acceleration sensor 2025, accelerator pedal depression amount signals obtained by the accelerator pedal sensor 2029, brake pedal depression amount signals obtained by the brake pedal sensor 2026, shift lever operation signals obtained by the shift lever sensor 2027, detection signals for detecting obstacles, vehicles, pedestrians, etc. obtained by the object detection sensor 2028, etc.

[0268] Information service unit 2012 is comprised of various devices, such as a car navigation system, audio system, speakers, television, and radio, that provide (output) various types of information, including driving information, traffic information, and entertainment information, as well as one or more ECUs that control these devices. Information service unit 2012 utilizes information obtained from external devices via communication module 2013 and other means to provide various multimedia information and services to passengers in vehicle 2001. Information service unit 2012 may include input devices (e.g., keyboard, mouse, microphone, switches, buttons, sensors, touch panel, etc.) for receiving external input, and output devices (e.g., display, speaker, LED light, touch panel, etc.) for providing external output.

[0269] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents or reducing the driver's driving load, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning devices (such as GNSS), map information (such as high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyroscope systems (such as IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, AI processors, and one or more ECUs that control these devices. In addition, the driving assistance system unit 2030 sends and receives various information via the communication module 2013 to implement driving assistance functions or autonomous driving functions.

[0270] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 can transmit and receive data with the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, gear lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 in the electronic control unit 2010, memory (ROM, RAM) 2032, and sensors 2021 to 29 via the communication port 2033.

[0271] The communication module 2013 is controlled by the microprocessor 2031 of the electronic control unit 2010 and is a communication device capable of communicating with external devices. For example, various information can be transmitted and received with the external device via wireless communication. The communication module 2013 can be located inside or outside the electronic control unit 2010. The external device can also be, for example, a base station or a mobile station.

[0272] The communication module 2013 may also transmit at least one of the signals input to the electronic control unit 2010 from the various sensors 2021-2028, information obtained based on the signals, and information based on external (user) input obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021-2028, the information service unit 2012, etc. may also be referred to as an input unit that receives input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above input.

[0273] The communication module 2013 receives various information (traffic information, signal information, inter-vehicle information, etc.) transmitted from external devices and displays it on the information service unit 2012 of the vehicle 2001. The information service unit 2012 can also be referred to as an output unit that outputs information (for example, outputs information to a display, speaker, or other device based on the PDSCH received by the communication module 2013 (or data / information decoded from the PDSCH)). In addition, the communication module 2013 stores various information received from external devices in the memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 can also control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, gear lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021 to 2029, and the like of the vehicle 2001.

[0274] (Summary of Implementation Methods)

[0275] As described above, according to an embodiment of the present invention, a terminal is provided, comprising: a receiving unit that performs LBT (Listen before talk) in an unlicensed band immediately before a first symbol candidate to be sent or a second symbol candidate to be sent; a control unit that sets parameters for transmission starting from the first symbol candidate and transmission starting from the second symbol candidate; and a transmitting unit that, if the LBT succeeds, applies the parameters corresponding to the symbol candidate to be sent starting from the symbol candidate to be sent immediately after the LBT and starts transmission to other terminals.

[0276] With the above configuration, when multiple transmission start symbol candidates are configured for inter-UE direct communication using one or more RB sets in the unlicensed band, optimal parameters can be applied to transmission of each candidate. In other words, optimal parameters suitable for transmission in inter-UE direct communication in the unlicensed band can be determined.

[0277] Alternatively, the first symbol candidate may be located at the beginning of a time resource usable for inter-terminal communication, and the second symbol candidate may be located midway through the time resource. With this configuration, in inter-terminal direct communication using one or more RB sets in an unlicensed band, when multiple transmission start symbol candidates are set, optimal parameters can be applied to transmission of each candidate.

[0278] Alternatively, the control unit may configure the parameters for transmitting a PSCCH (Physical Sidelink Control Channel) or a PSSCH (Physical Sidelink Shared Channel). With this configuration, when multiple transmission start symbol candidates are configured in inter-UE direct communication using one or more RB sets in an unlicensed band, optimal parameters can be applied to transmission of each candidate.

[0279] Alternatively, when transmission is performed across multiple RB (Resource Block) sets, the control unit may determine which of the first symbol candidate or the second symbol candidate to start transmission from within the multiple RB sets based on which of the first symbol candidate or the second symbol candidate can be started for transmission within each RB set. This configuration allows for flexible determination of which starting symbol candidate to start transmission from when transmission is performed across multiple RB sets.

[0280] Alternatively, the control unit may determine whether to execute transmission starting from the first symbol candidate or the second symbol candidate based on whether transmission can be started from the first symbol candidate or the second symbol candidate in all of the plurality of RB sets. With this configuration, transmission can be executed only when TB transmission can be reliably executed, thereby avoiding transmission with a low probability of successful reception.

[0281] Furthermore, according to an embodiment of the present invention, a communication method is provided, in which a terminal performs the following steps: performing listen-before-talk (LBT) in an unlicensed band immediately before a first symbol candidate to be sent or a second symbol candidate to be sent; setting parameters for transmission starting from the first symbol candidate and transmission starting from the second symbol candidate; and, if the LBT is successful, starting from the symbol candidate to be sent immediately after the LBT, applying the parameters corresponding to the symbol candidate to be sent, and starting transmission to other terminals.

[0282] With the above configuration, when multiple transmission start symbol candidates are configured for inter-UE direct communication using one or more RB sets in the unlicensed band, optimal parameters can be applied to transmission of each candidate. In other words, optimal parameters suitable for transmission in inter-UE direct communication in the unlicensed band can be determined.

[0283] (Supplementary Implementation Methods)

[0284] The above describes the embodiments of the present invention, but the disclosed invention is not limited to such embodiments, and those skilled in the art should understand various variations, modifications, substitutions, replacements, etc. In order to facilitate understanding of the invention, specific numerical examples are used for description, but unless otherwise specified, these numerical values ​​are only examples, and any appropriate values ​​may also be used. The distinction between items in the above description is not essential to the present invention. You can combine and use the matters recorded in two or more items as needed, and you can also apply the matters recorded in a certain item to the matters recorded in another item (as long as there is no contradiction). The boundaries of the functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of the physical components. The actions of multiple functional units can be performed by one physical component, or the actions of one functional unit can be performed by multiple physical components. Regarding the processing steps described in the embodiment, the order of processing can be swapped if there is no contradiction. For the convenience of explaining the processing, the base station 10 and the terminal 20 are described using a functional block diagram, but such a device can also be implemented by hardware, software, or a combination thereof. The software that operates in accordance with the embodiments of the present invention through the processor of the base station 10 and the software that operates in accordance with the embodiments of the present invention through the processor of the terminal 20 can also be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server and any other appropriate storage medium.

[0285] In addition, the notification of information is not limited to the form / implementation method described in the present disclosure, and other methods may also be used. For example, the notification of information can be implemented through physical layer signaling (for example, DCI (Downlink Control Information), UCI (Uplink Control Information)), high-layer signaling (for example, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals or a combination thereof. In addition, RRC signaling may also be referred to as an RRC message, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, etc.

[0286] Each form / embodiment described in the present disclosure can also be applied to LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6G (6th generation mobile communication system), xG (xth generation mobile communication system) (xG (x is, for example, an integer or a decimal)), FRA (Future Radio Access), NR (New Radio), New Radio Access (NX), Future Generation Radio Access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE At least one of 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), other appropriate systems, and next-generation systems that are expanded, modified, created, or specified based on these systems. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G) may also be employed.

[0287] The processing steps, sequences, and flows of each form / implementation described in this specification may be rearranged in order unless there is a conflict. For example, the methods described in this disclosure use an illustrative order to present the elements of various steps, but are not limited to the specific order presented.

[0288] In this specification, specific actions performed by base station 10 may also be performed by its upper node, depending on the situation. In a network consisting of one or more network nodes including base station 10, it is obvious that various actions performed for communication with terminal 20 can be performed by at least one of base station 10 and other network nodes other than base station 10 (e.g., MME or S-GW, but not limited to these). While the above example illustrates a single other network node other than base station 10, the other network node may also be a combination of multiple other network nodes (e.g., MME and S-GW).

[0289] The information or signals described in this disclosure can be output from a higher layer (or lower layer) to a lower layer (or higher layer), and can also be input or output via multiple network nodes.

[0290] Input or output information can be stored in a specific location (e.g., memory) or managed using a management table. Input or output information can be rewritten, updated, or appended. Output information can also be deleted. Input information can also be sent to other devices.

[0291] The determination in the present disclosure can be made by a value represented by 1 bit (0 or 1), a Boolean value (Boolean: true or false), or by comparison of numerical values ​​(for example, comparison with a predetermined value).

[0292] Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or by other names, shall be interpreted broadly to refer to instructions, sets of instructions, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc.

[0293] Additionally, software, commands, information, and the like may be transmitted and received via a transmission medium. For example, if software is transmitted from a web page, server, or other remote source using at least one of a wired technology (coaxial cable, fiber optic cable, twisted pair, DSL, etc.) and a wireless technology (infrared, microwave, etc.), at least one of these wired and wireless technologies is included within the definition of a transmission medium.

[0294] The information, signals, etc. described in this disclosure may also be represented using any of a variety of different technologies. For example, data, commands, instructions, information, signals, bits, symbols, chips, etc. that may be referred to in the entire description may also be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0295] In addition, the terms used in this disclosure and those necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may also be referred to as a carrier frequency, a cell, or a frequency carrier.

[0296] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0297] In addition, the information, parameters, etc. described in this disclosure can be expressed using absolute values, relative values ​​relative to predetermined values, or other corresponding information. For example, wireless resources can also be indicated using indexes.

[0298] The names used for the above parameters are non-limiting in any respect. Furthermore, the formulas and the like using these parameters may sometimes differ from those explicitly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable names, and therefore the names assigned to these channels and information elements are non-limiting in any respect.

[0299] In this disclosure, terms such as "base station (BS)," "wireless base station," "base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" are used interchangeably. Base stations are sometimes also referred to as macrocells, small cells, femtocells, and picocells.

[0300] A base station can accommodate one or more (for example, three) cells. When a base station accommodates multiple cells, the base station's overall coverage area can be divided into multiple smaller areas, each of which can also provide communication services through a base station subsystem (for example, a small base station (RRH) for indoor use). Terms such as "cell" or "sector" refer to a portion or the entire coverage area of ​​at least one of the base station and base station subsystem that provide communication services within that coverage area.

[0301] In the present disclosure, the base station sending information to the terminal may also be replaced by the base station instructing the terminal to perform a control / action based on the information.

[0302] In the present disclosure, terms such as “mobile station (MS)”, “user terminal (user terminal)”, “user equipment (UE)”, and “terminal” can be used interchangeably.

[0303] For mobile stations, those skilled in the art sometimes also use the following terms to refer to them: subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other appropriate terms.

[0304] At least one of the base station and the mobile station may also be referred to as a transmitting device, a receiving device, a communication device, etc. In addition, at least one of the base station and the mobile station may also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body refers to an object that can move, and the moving speed is arbitrary. In addition, of course, the situation where the mobile body stops is also included. The mobile body includes, for example, vehicles, transport vehicles, cars, motorcycles, bicycles, connected cars, shovel cars, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, rear cars, rickshaws, ships and other watercraft, airplanes, rockets, artificial satellites, drones (registered trademark), multicopters, quadcopters, balloons, and objects mounted thereon, and is not limited thereto. In addition, the mobile body may also be a mobile body that drives autonomously based on an operating instruction. It can be a vehicle (such as a car or airplane), a mobile object that moves unmanned (such as a drone or self-driving car), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station also includes a device that does not necessarily move during communication. For example, at least one of the base station and the mobile station can be an IoT (Internet of Things) device such as a sensor.

[0305] In addition, the base station in the present disclosure can also be replaced by a user terminal. For example, the various forms / implementations of the present disclosure can also be applied to a structure in which the communication between the base station and the user terminal is replaced by the communication between multiple terminals 20 (for example, it can also be called D2D (Device-to-Device: device to device), V2X (Vehicle-to-Everything: vehicle-to-everything) etc.). In this case, it can also be set as a structure in which the terminal 20 has the functions of the above-mentioned base station 10. In addition, terms such as "uplink" and "downlink" can also be replaced by terms corresponding to communication between terminals (for example, "side"). For example, uplink channels, downlink channels, etc. can also be replaced by side channels.

[0306] Likewise, the user terminal in the present disclosure may be replaced by a base station. In this case, the base station may have the functions of the user terminal.

[0307] As used in this disclosure, terms such as "determining" and "determining" sometimes encompass a variety of actions. For example, "determining" and "judging" may include considering matters such as judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining as matters that have been "judged" or "determined." Furthermore, "determining" and "receiving" (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in a memory) as matters that have been "judged" or "determined." Furthermore, "determining" and "resolving" may include matters such as selecting, choosing, establishing, or comparing. That is, "judgment" and "decision" can include matters where certain actions are considered to have been "judged" or "decided." In addition, "judgment (decision)" can also be replaced by "assuming (assuming)," "expecting (expecting)", "considering (considering)", etc.

[0308] The terms "connected", "coupled" or all variations of these terms are intended to indicate any direct or indirect connection or combination between two or more elements, and may include situations where there is one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The combination or connection between elements may be a physical combination or connection, a logical combination or connection, or a combination of these. For example, "access" may be used instead of "connection". As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using at least one of one or more wires, cables and printed electrical connections, and as some non-limiting and non-inclusive examples, electromagnetic energy having wavelengths in the wireless frequency domain, microwave region and light (including both visible and invisible) region may be used to "connect" or "couple" to each other.

[0309] The reference signal may be referred to as RS (Reference Signal) for short, or may be called a pilot signal depending on the applied standard.

[0310] The phrase “based on” used in this disclosure does not mean “based only on” unless explicitly stated otherwise. In other words, the phrase “based on” means both “based only on” and “based at least on.”

[0311] Any reference to an element using the designations "first," "second," etc., as used in this disclosure, does not necessarily limit the number or order of these elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Therefore, a reference to a first element and a second element does not imply that only two elements can be used or that the first element must precede the second element in any manner.

[0312] The “unit” in the configuration of each of the above-mentioned devices may be replaced with a “section,” “circuit,” “device,” or the like.

[0313] When the terms "include," "including," and variations thereof are used in this disclosure, these terms, like the term "comprising," are intended to be inclusive. Furthermore, the term "or" used in this disclosure does not mean an exclusive or.

[0314] A radio frame can be composed of one or more frames in the time domain. In the time domain, one or more frames can be called a subframe. A subframe can also be composed of one or more time slots in the time domain. A subframe can also be a fixed time length (e.g., 1 ms) that is independent of the numerology.

[0315] A parameter set may be a communication parameter applied to at least one of the transmission and reception of a signal or channel. For example, the parameter set may represent at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering performed by the transceiver in the frequency domain, specific windowing performed by the transceiver in the time domain, and the like.

[0316] A slot may be composed of one or more symbols (OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.) in the time domain. A slot may be a time unit based on a parameter set.

[0317] A time slot may contain multiple mini-slots. Each mini-slot may consist of one or more symbols in the time domain. Furthermore, a mini-slot may also be referred to as a sub-slot. A mini-slot may consist of fewer symbols than a time slot. A PDSCH (or PUSCH) transmitted in time units larger than a mini-slot may be referred to as PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be referred to as PDSCH (or PUSCH) mapping type B.

[0318] Radio frame, subframe, time slot, mini-time slot, and symbol all represent time units for signal transmission. Radio frame, subframe, time slot, mini-time slot, and symbol may be referred to by other corresponding names.

[0319] For example, a subframe can be called a Transmission Time Interval (TTI), multiple consecutive subframes can be called a TTI, and a slot or mini-slot can be called a TTI. That is, at least one of a subframe and a TTI can be a subframe (1ms) in existing LTE, a period shorter than 1ms (for example, 1-13 symbols), or a period longer than 1ms. Furthermore, the unit representing a TTI can be called a slot, a mini-slot, or the like, rather than a subframe.

[0320] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communications. For example, in the LTE system, a base station schedules the allocation of wireless resources (such as the frequency bandwidth and transmit power available to each terminal 20) to each terminal 20 using TTIs as units. The definition of TTI is not limited to this.

[0321] A TTI can be a unit of time for transmitting data packets (transport blocks), code blocks, code words, etc. after channel coding, or a unit of processing such as scheduling and link adaptation. Furthermore, when a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, code block, code word, etc. is actually mapped can be shorter than the TTI.

[0322] In addition, when one time slot or one mini-time slot is called a TTI, one or more TTIs (i.e., one or more time slots or one or more mini-time slots) can also be the minimum time unit for scheduling. In addition, the number of time slots (mini-time slots) that constitute the minimum time unit for scheduling can also be controlled.

[0323] A TTI with a time length of 1 ms is also called a normal TTI (TTI in LTE Rel. 8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a time slot, etc. A TTI shorter than a normal TTI may also be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a minislot, a subslot, a time slot, etc.

[0324] In addition, for long TTI (for example, normal TTI, subframe, etc.), it can be understood as a TTI with a time length of more than 1ms, and for short TTI (for example, shortened TTI, etc.), it can be understood as a TTI with a TTI length smaller than long TTI (long TTI) and greater than 1ms.

[0325] A resource block (RB) is a unit of resource allocation in the time and frequency domains. In the frequency domain, it can contain one or more consecutive subcarriers. The number of subcarriers contained in an RB can be the same regardless of the parameter set, for example, it can be 12. The number of subcarriers contained in an RB can also be determined by the parameter set.

[0326] In addition, the time domain of an RB may include one or more symbols and may be the length of one slot, one mini-slot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0327] In addition, one or more RBs may also be referred to as a physical resource block (PRB: Physical RB), a sub-carrier group (SCG: Sub-Carrier Group), a resource element group (REG: Resource Element Group), a PRB pair, an RB pair, etc.

[0328] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0329] A bandwidth part (BWP) (also referred to as a fractional bandwidth) can also represent a subset of contiguous common resource blocks (RBs) used for a particular parameter set within a particular carrier. Common RBs can be identified by their index relative to the common reference point for that carrier. PRBs can be defined within a BWP and numbered within that BWP.

[0330] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for the terminal 20 within one carrier.

[0331] At least one of the set BWPs may be active, and it is not assumed that the terminal 20 transmits or receives predetermined signals / channels outside the active BWP. In addition, "cell", "carrier", etc. in the present disclosure may be replaced with "BWP".

[0332] The above-described structures of radio frames, subframes, slots, mini-slots, and symbols are merely examples. For example, various modifications may be made to the structures, such as the number of subframes in a radio frame, the number of slots per subframe or radio frame, the number of mini-slots in a slot, the number of symbols and RBs in a slot or mini-slot, the number of subcarriers in an RB, the number of symbols in a TTI, the symbol length, and the cyclic prefix (CP) length.

[0333] In the present disclosure, when an article is added by translation, such as a, an, and the in English, the present disclosure also includes cases where the noun following the article is in plural form.

[0334] In this disclosure, the phrase "A and B are different" can mean "A and B are different from each other." Alternatively, the phrase can mean "A and B are each different from C." Terms such as "separate" and "combined" can also be interpreted in the same way as "different."

[0335] Each form / implementation described in this disclosure may be used individually or in combination, and may be switched between them depending on the execution. Furthermore, notification of scheduled information is not limited to being performed explicitly (e.g., a notification of "yes X") but may also be performed implicitly (e.g., not notifying the scheduled information).

[0336] While the present disclosure has been described in detail above, it should be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in various modifications and variations without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is for illustrative purposes only and does not have any limiting meaning on the present disclosure.

[0337] Label Description

[0338] 10 base stations

[0339] 110 Sending Department

[0340] 120 Receiving Department

[0341] 130 Setting Department

[0342] 140 Control Department

[0343] 20 Terminal

[0344] 210 Sending Department

[0345] 220 Receiving Department

[0346] 230 Setting Department

[0347] 240 Control Department

[0348] 1001 Processor

[0349] 1002 Storage Device

[0350] 1003 Auxiliary storage device

[0351] 1004 Communication device

[0352] 1005 Input Device

[0353] 1006 Output Device

[0354] 2001 Vehicle

[0355] 2002 Drive Department

[0356] 2003 Steering

[0357] 2004 Accelerator Pedal

[0358] 2005 Brake Pedal

[0359] 2006 gear lever

[0360] 2007 front wheel

[0361] 2008 rear wheel

[0362] 2009 Axle

[0363] 2010 Electronic Control Department

[0364] 2012 Information Services Department

[0365] 2013 Communication Module

[0366] 2021 Current Sensor

[0367] 2022 Speed ​​Sensor

[0368] 2023 Air Pressure Sensor

[0369] 2024 Vehicle Speed ​​Sensor

[0370] 2025 Accelerometer

[0371] 2026 Brake Pedal Sensor

[0372] 2027 Gearshift sensor

[0373] 2028 Object Detection Sensor

[0374] 2029 Accelerator pedal sensor

[0375] 2030 Driving Assistance Systems Department

[0376] 2031 Microprocessor

[0377] 2032 memory (ROM, RAM)

[0378] 2033 Communication port (IO port)

Claims

1. A terminal comprising: a receiving unit configured to perform listen-before-talk (LBT) immediately before the start of transmission of a first symbol candidate or the start of transmission of a second symbol candidate in an unlicensed band; a control unit configured to set parameters for transmission starting from the first symbol candidate and for transmission starting from the second symbol candidate; as well as A transmitting unit that, when the LBT succeeds, applies the parameters corresponding to the symbol candidate to be sent starting from the symbol candidate to be sent immediately after the LBT and starts sending to other terminals.

2. The terminal according to claim 1, wherein: The first symbol candidate is located at the beginning of a time resource that can be used for inter-terminal communication, and the second symbol candidate is located in the middle of the time resource.

3. The terminal according to claim 1, wherein: The control unit sets the parameters for transmitting a physical link control channel (PSCCH) or a physical link shared channel (PSSCH). The terminal according to claim 2 , wherein: When the control unit performs transmission in multiple RB sets, i.e., resource block sets, the control unit decides which of the first codeword candidate or the second codeword candidate to start transmission from among the multiple RB sets based on which of the first codeword candidate or the second codeword candidate can be started from in each RB set. The terminal according to claim 4 , wherein: The control unit determines whether to execute transmission starting from each of the first symbol candidate or the second symbol candidate based on whether transmission can be started from the first symbol candidate or the second symbol candidate in all of the plurality of RB sets.

6. A communication method, wherein: The terminal performs the following steps: In the unlicensed band, listen-before-talk (LBT) is performed immediately before the start of sending the first symbol candidate or the start of sending the second symbol candidate. setting parameters for transmission starting from the first symbol candidate and for transmission starting from the second symbol candidate; as well as When the LBT is successful, the parameters corresponding to the symbol candidate to be sent are applied starting from the symbol candidate to be sent immediately after the LBT, and transmission to other terminals is started.

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