Terminal and communication method

Abstract

To improve the reliability of communication at the time of an autonomous resource selection in direct communication between terminals.SOLUTION: A first terminal includes: a receiving unit that receives first reservation information reserving a first resource from a second terminal and receives second reservation information reserving a second resource from a third terminal; a control unit that, when a destination related to the first reservation information is not the first terminal but a destination related to the second reservation information is the first terminal, identifies a terminal, which is to be a destination of information regarding a collision between the first resource and the second resource based on a first priority related to the first reservation information and a second priority related to the second reservation information; and a transmitting unit that transmits the information regarding the collision to the identified terminal.SELECTED DRAWING: Figure 21

Description

[Technical field]

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

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

[0003] D2D reduces traffic between terminals and base stations, and enables communication between terminals even when the base station becomes unable to communicate due to a disaster or the like. In addition, although 3GPP (3rd Generation Partnership Project) refers to D2D as "sidelink," the more general term D2D is used in this specification. However, in the description of the embodiments described later, sidelink is also used as necessary.

[0004] D2D communication is broadly divided into D2D discovery (also referred to as D2D discovery) for discovering other terminals with which communication is possible, and D2D communication (also referred to as D2D direct communication, D2D communication, direct communication between terminals, etc.) for direct communication between terminals. Hereinafter, when there is no particular distinction between D2D communication, D2D discovery, etc., they are simply referred to as D2D. Furthermore, signals transmitted and received in D2D are referred to as D2D signals. Various use cases for services related to V2X (Vehicle to Everything) in NR are being considered (for example, Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] 3GPP TS 38.211 V16.2.0(2020-06) [Non-Patent Document 2] 3GPP TR 22.886 V15.1.0(2017-03) Summary of the Invention [Problem to be solved by the invention]

[0006] Power saving is being considered as an enhancement to the NR sidelink. For example, in resource allocation mode 2, in which a terminal autonomously selects resources, the terminal performs partial sensing on limited resources within a sensing window, and selects available resource candidates from the resource selection window based on the results.

[0007] Here, in resource allocation mode 2, when the transmitting terminal performs sensing, for example, if there is another terminal outside the line of sight of the transmitting terminal, the quality of the resource at the receiving terminal may be significantly different from the quality based on the results of sensing the resource by the transmitting terminal.

[0008] The present invention has been made in consideration of the above-mentioned points, and has an object to improve the reliability of communication when autonomous resource selection is performed in direct communication between terminals. [Means for solving the problem]

[0009] According to the disclosed technology, a first terminal includes a receiving unit that receives first reservation information reserving a first resource from a second terminal and receives second reservation information reserving a second resource from a third terminal; a control unit that, when a destination related to the first reservation information is not the first terminal but a destination related to the second reservation information is the first terminal, identifies a terminal to which information regarding a collision between the first resource and the second resource is to be sent based on a first priority related to the first reservation information and a second priority related to the second reservation information; and a transmitting unit that transmits information regarding the collision to the identified terminal. Effect of the Invention

[0010] According to the disclosed technology, it is possible to improve the reliability of communication during autonomous resource selection in direct communication between terminals. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram for explaining V2X. [Diagram 2] FIG. 1 is a diagram for explaining an example (1) of a V2X transmission mode. [Diagram 3] FIG. 13 is a diagram for explaining an example (2) of a V2X transmission mode. [Figure 4] FIG. 13 is a diagram for explaining an example (3) of a V2X transmission mode. [Diagram 5] FIG. 13 is a diagram for explaining an example (4) of a V2X transmission mode. [Figure 6] FIG. 13 is a diagram for explaining an example (5) of a V2X transmission mode. [Figure 7] FIG. 1 is a diagram for explaining an example (1) of a V2X communication type. [Figure 8] FIG. 1 is a diagram for explaining an example (2) of a V2X communication type. [Figure 9] FIG. 13 is a diagram for explaining an example (3) of a V2X communication type. [Figure 10] FIG. 1 is a sequence diagram showing an operation example (1) of V2X. [Figure 11] FIG. 11 is a sequence diagram showing an operation example (2) of V2X. [Figure 12] FIG. 11 is a sequence diagram showing an operation example (3) of V2X. [Figure 13] FIG. 11 is a sequence diagram showing an operation example (4) of V2X. [Figure 14] FIG. 1 is a diagram illustrating an example of a sensing operation in LTE. [Figure 15] FIG. 1 is a diagram illustrating an example of partial sensing operation in LTE. [Figure 16] FIG. 1 is a diagram illustrating an example of a sensing operation in NR. [Figure 17] FIG. 1 is a diagram illustrating an example (1) of D2D communication. [Figure 18] FIG. 13 is a diagram illustrating an example (2) of D2D communication. [Figure 19] FIG. 2 is a diagram showing an example (1) of D2D communication according to an embodiment of the present invention. [Figure 20] FIG. 11 is a diagram illustrating an example (2) of D2D communication according to the embodiment of the present invention. [Figure 21] FIG. 11 is a diagram illustrating an example (3) of D2D communication according to an embodiment of the present invention. [Figure 22] FIG. 11 is a diagram showing an example (4) of D2D communication according to the embodiment of the present invention. [Diagram 23] 1 is a flowchart illustrating an example of preemption in NR. [Figure 24] A diagram showing an example of preemption in NR. [Diagram 25] 2 is a diagram illustrating an example of a functional configuration of a base station 10 according to an embodiment of the present invention. [Figure 26] 2 is a diagram illustrating an example of a functional configuration of a terminal 20 according to an embodiment of the present invention. [Figure 27] 2 is a diagram illustrating an example of a hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0013] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are used as appropriate. However, the existing technologies are, for example, existing LTE, but are not limited to existing LTE. In addition, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems after LTE-Advanced (e.g., NR), or wireless LAN (Local Area Network), unless otherwise specified.

[0014] Furthermore, in the embodiment of the present invention, the duplexing method may be a time division duplex (TDD) method, a frequency division duplex (FDD) method, or another method (for example, flexible duplex, etc.).

[0015] Furthermore, in the embodiment of the present invention, when radio parameters, etc. are "configured," this may mean that predetermined values ​​are pre-configured, or that radio parameters notified from base station 10 or terminal 20 are configured.

[0016] FIG. 1 is a diagram for explaining V2X. In 3GPP, realization of V2X (Vehicle to Everything) or eV2X (enhanced V2X) by extending the D2D function is being considered, and specifications are being developed. As shown in FIG. 1, V2X is a part of ITS (Intelligent Transport Systems), and is a general term for V2V (Vehicle to Vehicle), which means a form of communication between vehicles, V2I (Vehicle to Infrastructure), which means a form of communication between a vehicle and a road-side unit (RSU: Road-Side Unit) installed on the side of the road, V2N (Vehicle to Network), which means a form of communication between a vehicle and an ITS server, and V2P (Vehicle to Pedestrian), which means a form of communication between a vehicle and a mobile terminal carried by a pedestrian.

[0017] In addition, 3GPP is studying V2X using LTE or NR cellular communication and terminal-to-terminal communication. V2X using cellular communication is also called cellular V2X. For NR V2X, studies are underway to achieve large capacity, low latency, high reliability, and QoS (Quality of Service) control.

[0018] It is expected that in the future, studies will be conducted on LTE or NR V2X that are not limited to 3GPP specifications. For example, it is expected that studies will be conducted on ensuring interoperability, reducing costs by implementing higher layers, using or switching between multiple RATs (Radio Access Technologies), complying with regulations in each country, and data acquisition, distribution, database management, and utilization methods for LTE or NR V2X platforms.

[0019] In the embodiment of the present invention, a form in which a communication device is mounted on a vehicle is mainly assumed, but the embodiment of the present invention is not limited to this form. For example, the communication device may be a terminal held by a person, a device mounted on a drone or an aircraft, a base station, an RSU, a relay station (relay node), a terminal having scheduling capability, etc.

[0020] In addition, SL (Sidelink) may be distinguished from UL (Uplink) or DL ​​(Downlink) based on any one or a combination of 1) to 4) below. SL may also be called by other names. 1) Resource allocation in the time domain 2) Frequency domain resource allocation 3) Reference synchronization signal (including SLSS (Sidelink Synchronization Signal)) 4) Reference signal used for path loss measurement for transmission power control

[0021] Furthermore, with regard to SL or UL Orthogonal Frequency Division Multiplexing (OFDM), any of Cyclic-Prefix OFDM (CP-OFDM), Discrete Fourier Transform - Spread - OFDM (DFT-S-OFDM), OFDM without transform precoding, or OFDM with transform precoding may be applied.

[0022] In the LTE SL, Mode 3 and Mode 4 are specified for SL resource allocation to terminal 20. In Mode 3, transmission resources are dynamically allocated by DCI (Downlink Control Information) transmitted from base station 10 to terminal 20. Also, in Mode 3, SPS (Semi Persistent Scheduling) is possible. In Mode 4, terminal 20 autonomously selects transmission resources from a resource pool.

[0023] In addition, the slot in the embodiment of the present invention may be replaced with a symbol, a minislot, a subframe, a radio frame, or a TTI (Transmission Time Interval). Also, the cell in the embodiment of the present invention may be replaced with a cell group, a carrier component, a BWP, a resource pool, a resource, a RAT (Radio Access Technology), a system (including a wireless LAN), etc.

[0024] In the embodiment of the present invention, the terminal 20 is not limited to a V2X terminal, and may be any type of terminal that performs D2D communication. For example, the terminal 20 may be a terminal carried by a user, such as a smartphone, or may be an IoT (Internet of Things) device, such as a smart meter.

[0025] FIG. 2 is a diagram for explaining an example of a transmission mode (1) of V2X. In the transmission mode of sidelink communication shown in FIG. 2, in step 1, the base station 10 transmits sidelink scheduling to the terminal 20A. Then, the terminal 20A transmits a PSCCH (Physical Sidelink Control Channel) and a PSSCH (Physical Sidelink Shared Channel) to the terminal 20B based on the received scheduling (step 2). The transmission mode of sidelink communication shown in FIG. 2 may be called sidelink transmission mode 3 in LTE. In the sidelink transmission mode 3 in LTE, Uu-based sidelink scheduling is performed. Uu is a radio interface between a universal terrestrial radio access network (UTRAN) and a user equipment (UE). The transmission mode of sidelink communication shown in FIG. 2 may be called sidelink transmission mode 1 in NR.

[0026] Fig. 3 is a diagram for explaining an example (2) of a transmission mode of V2X. In the transmission mode of sidelink communication shown in Fig. 3, in step 1, the terminal 20A transmits the PSCCH and the PSSCH to the terminal 20B by using autonomously selected resources. The transmission mode of sidelink communication shown in Fig. 3 may be called sidelink transmission mode 4 in LTE. In sidelink transmission mode 4 in LTE, the UE itself performs resource selection.

[0027] FIG. 4 is a diagram for explaining an example of a transmission mode (3) of V2X. In the transmission mode of sidelink communication shown in FIG. 4, in step 1, the terminal 20A transmits PSCCH and PSSCH to the terminal 20B using autonomously selected resources. Similarly, the terminal 20B transmits PSCCH and PSSCH to the terminal 20A using autonomously selected resources (step 1). The transmission mode of sidelink communication shown in FIG. 4 may be called a sidelink transmission mode 2a in NR. In sidelink transmission mode 2 in NR, the terminal 20 itself performs resource selection.

[0028] Fig. 5 is a diagram for explaining an example (4) of a transmission mode of V2X. In the transmission mode of sidelink communication shown in Fig. 5, in step 0, a resource pattern of sidelink is transmitted from the base station 10 to the terminal 20A via RRC (Radio Resource Control) configuration or is set in advance. Then, the terminal 20A transmits a PSSCH to the terminal 20B based on the resource pattern (step 1). The transmission mode of sidelink communication shown in Fig. 5 may be referred to as a sidelink transmission mode 2c in NR.

[0029] Fig. 6 is a diagram for explaining an example (5) of a transmission mode of V2X. In the transmission mode of sidelink communication shown in Fig. 6, in step 1, the terminal 20A transmits sidelink scheduling to the terminal 20B via the PSCCH. Then, the terminal 20B transmits the PSSCH to the terminal 20A based on the received scheduling (step 2). The transmission mode of sidelink communication shown in Fig. 6 may be referred to as a sidelink transmission mode 2d in NR.

[0030] Fig. 7 is a diagram for explaining an example (1) of a V2X communication type. The communication type of the side link shown in Fig. 7 is unicast. The terminal 20A transmits a PSCCH and a PSSCH to the terminal 20. In the example shown in Fig. 7, the terminal 20A unicasts to the terminal 20B and also unicasts to the terminal 20C.

[0031] Fig. 8 is a diagram for explaining an example (2) of a V2X communication type. The sidelink communication type shown in Fig. 8 is groupcast. Terminal 20A transmits PSCCH and PSSCH to a group to which one or more terminals 20 belong. In the example shown in Fig. 8, the group includes terminal 20B and terminal 20C, and terminal 20A performs groupcast to the group.

[0032] FIG. 9 is a diagram for explaining an example (3) of a V2X communication type. The sidelink communication type shown in FIG. 9 is broadcast. Terminal 20A transmits PSCCH and PSSCH to one or more terminals 20. In the example shown in FIG. 9, terminal 20A broadcasts to terminal 20B, terminal 20C, and terminal 20D. Note that terminal 20A shown in FIGS. 7 to 9 may be referred to as a header UE (header-UE).

[0033] In addition, it is expected that NR-V2X will support hybrid automatic repeat request (HARQ) for unicast and groupcast sidelinks. Furthermore, SFCI (Sidelink Feedback Control Information) including a HARQ response will be defined in NR-V2X. Furthermore, it is being considered that SFCI will be transmitted via a physical sidelink feedback channel (PSFCH).

[0034] In the following description, the PSFCH is used in transmitting the HARQ-ACK on the side link, but this is just an example. For example, the HARQ-ACK may be transmitted on the side link using the PSCCH, the HARQ-ACK may be transmitted on the side link using the PSSCH, or the HARQ-ACK may be transmitted on the side link using another channel.

[0035] For convenience, the information reported by the terminal 20 in HARQ will be generally referred to as HARQ-ACK below. This HARQ-ACK may also be referred to as HARQ-ACK information. More specifically, a codebook applied to the HARQ-ACK information reported from the terminal 20 to the base station 10 or the like will be referred to as a HARQ-ACK codebook. The HARQ-ACK codebook specifies the bit string of the HARQ-ACK information. In addition to ACK, NACK is also transmitted by "HARQ-ACK".

[0036] Fig. 10 is a sequence diagram showing an operation example (1) of V2X. As shown in Fig. 10, the wireless communication system according to the embodiment of the present invention may have a terminal 20A and a terminal 20B. Note that, although there are actually many user devices, Fig. 10 shows the terminal 20A and the terminal 20B as an example.

[0037] Hereinafter, when there is no particular distinction between the terminals 20A, 20B, etc., they will be simply referred to as "terminal 20" or "user device." In Fig. 10, as an example, a case where the terminals 20A and 20B are both within the coverage of a cell is shown, but the operation in the embodiment of the present invention can also be applied to a case where the terminal 20B is outside the coverage.

[0038] As described above, in the present embodiment, the terminal 20 is, for example, a device mounted on a vehicle such as an automobile, and has a cellular communication function as a UE in LTE or NR, and a side link function. The terminal 20 may be a general mobile terminal (such as a smartphone). The terminal 20 may also be an RSU. The RSU may be a UE type RSU having a UE function, or a gNB type RSU having a base station device function.

[0039] It is not necessary for the terminal 20 to be a device in a single housing. For example, even if various sensors are arranged in a dispersed manner within a vehicle, the terminal 20 may be a device including the various sensors.

[0040] Furthermore, the processing of sidelink transmission data in terminal 20 is basically the same as the processing of UL transmission in LTE or NR. For example, terminal 20 scrambles and modulates codewords of transmission data to generate complex-valued symbols, maps the complex-valued symbols (transmission signals) to one or two layers, and performs precoding. Then, terminal 20 maps the precoded complex-valued symbols to resource elements to generate transmission signals (e.g., complex-valued time-domain SC-FDMA signals), and transmits them from each antenna port.

[0041] The base station 10 has a function of cellular communication as a base station in LTE or NR, and a function for enabling communication of the terminal 20 in the present embodiment (e.g., resource pool setting, resource allocation, etc.). The base station 10 may be an RSU (gNB type RSU).

[0042] Furthermore, in the wireless communication system according to the embodiment of the present invention, the signal waveform used by terminal 20 for SL or UL may be OFDMA, SC-FDMA, or another signal waveform.

[0043] In step S101, the terminal 20A autonomously selects resources to be used for the PSCCH and the PSSCH from a resource selection window having a predetermined period. The resource selection window may be set in the terminal 20 by the base station 10. Here, the predetermined period of the resource selection window may be defined by implementation conditions of the terminal, such as processing time or maximum allowable packet delay time, or may be defined in advance by specifications, or the predetermined period may be called an interval in the time domain.

[0044] In steps S102 and S103, the terminal 20A transmits SCI (Sidelink Control Information) by PSCCH and / or PSSCH using the resource autonomously selected in step S101, and transmits SL data by PSSCH. For example, the terminal 20A may transmit the PSCCH using a frequency resource adjacent to the frequency resource of the PSSCH in the same time resource as at least a part of the time resource of the PSSCH.

[0045] The terminal 20B receives the SCI (PSCCH and / or PSSCH) and the SL data (PSSCH) transmitted from the terminal 20A. The received SCI may include information on the PSFCH resource for the terminal 20B to transmit a HARQ-ACK in response to the reception of the data. The terminal 20A may transmit information on the autonomously selected resource by including it in the SCI.

[0046] In step S104, the terminal 20B transmits a HARQ-ACK for the received data to the terminal 20A, using the PSFCH resource determined from the received SCI.

[0047] In step S105, if the HARQ-ACK received in step S104 indicates a request for retransmission, that is, if it is a NACK (negative response), the terminal 20A retransmits the PSCCH and PSSCH to the terminal 20B. The terminal 20A may retransmit the PSCCH and PSSCH using autonomously selected resources.

[0048] In addition, if HARQ control involving HARQ feedback is not performed, steps S104 and S105 do not need to be performed.

[0049] 11 is a sequence diagram showing an operation example (2) of V2X. Blind retransmission without HARQ control may be performed to improve the transmission success rate or reach.

[0050] In step S201, the terminal 20A autonomously selects resources to be used for the PSCCH and the PSSCH from a resource selection window having a predetermined period. The resource selection window may be set to the terminal 20 by the base station 10.

[0051] In steps S202 and S203, the terminal 20A transmits the SCI by the PSCCH and / or the PSSCH, and transmits the SL data by the PSSCH, using the resources autonomously selected in step S201. For example, the terminal 20A may transmit the PSCCH using a frequency resource adjacent to the frequency resource of the PSSCH, in the same time resource as at least a part of the time resource of the PSSCH.

[0052] In step S204, the terminal 20A retransmits the SCI by the PSCCH and / or the PSSCH and the SL data by the PSSCH to the terminal 20B, using the resource autonomously selected in step S201. The retransmission in step S204 may be performed multiple times.

[0053] If blind retransmission is not performed, step S204 does not need to be performed.

[0054] 12 is a sequence diagram showing an operation example (3) of V2X. The base station 10 may perform sidelink scheduling. That is, the base station 10 may determine sidelink resources to be used by the terminal 20 and transmit information indicating the resources to the terminal 20. Furthermore, when HARQ control involving HARQ feedback is applied, the base station 10 may transmit information indicating PSFCH resources to the terminal 20.

[0055] In step S301, the base station 10 performs SL scheduling by transmitting DCI (Downlink Control Information) via the PDCCH to the terminal 20 A. Hereinafter, for convenience, the DCI for SL scheduling is referred to as SL scheduling DCI.

[0056] Also, in step S301, it is assumed that the base station 10 also transmits DCI for DL ​​scheduling (which may also be called DL allocation) to the terminal 20A by the PDCCH. Hereinafter, for convenience, the DCI for DL ​​scheduling is called DL scheduling DCI. The terminal 20A that has received the DL scheduling DCI receives DL data by the PDSCH using resources specified in the DL scheduling DCI.

[0057] In steps S302 and S303, the terminal 20A transmits SCI (Sidelink Control Information) by PSCCH and / or PSSCH using resources specified by the SL scheduling DCI, and transmits SL data by PSSCH. Note that only the resources of the PSSCH may be specified in the SL scheduling DCI. In this case, for example, the 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 part of the time resources of the PSSCH.

[0058] The terminal 20B receives the SCI (PSCCH and / or PSSCH) and the SL data (PSSCH) transmitted from the terminal 20A. The SCI received by the PSCCH and / or PSSCH includes information on the resource of the PSFCH for the terminal 20B to transmit a HARQ-ACK in response to the reception of the data.

[0059] The resource information is included in the DL scheduling DCI or SL scheduling DCI transmitted from the base station 10 in step S301, and the terminal 20A acquires the resource information from the DL scheduling DCI or SL scheduling DCI and includes it in the SCI. Alternatively, the resource information may not be included in the DCI transmitted from the base station 10, and the terminal 20A may autonomously include the resource information in the SCI and transmit it.

[0060] In step S304, the terminal 20B transmits a HARQ-ACK for the received data to the terminal 20A, using the PSFCH resource determined from the received SCI.

[0061] In step S305, the terminal 20A transmits a HARQ-ACK using a PUCCH (Physical uplink control channel) resource specified by the DL scheduling DCI (or the SL scheduling DCI) at a timing (for example, slot-by-slot timing) specified by the DL scheduling DCI (or the SL scheduling DCI), and the base station 10 receives the HARQ-ACK. The codebook of the HARQ-ACK may include a HARQ-ACK generated based on the HARQ-ACK received from the terminal 20B or a PSFCH that was not received, and a HARQ-ACK for DL ​​data. However, when no DL data is allocated, the HARQ-ACK for DL ​​data is not included. In NR Rel. 16, the codebook of the HARQ-ACK does not include a HARQ-ACK for DL ​​data.

[0062] Note that, if HARQ control involving HARQ feedback is not performed, step S304 and / or step S305 may not be performed.

[0063] FIG. 13 is a sequence diagram showing an operation example (4) of V2X. As described above, in the NR sidelink, it is supported that the HARQ response is transmitted by the PSFCH. Note that the format of the PSFCH can be, for example, a format similar to PUCCH (Physical Uplink Control Channel) format 0. That is, the format of the PSFCH may be a sequence-based format in which the PRB (Physical Resource Block) size is 1 and ACK and NACK are identified by differences in sequence and / or cyclic shift. The format of the PSFCH is not limited to this. The PSFCH resource may be arranged in the last symbol or the last multiple symbols of the slot. In addition, a period N is set or predefined for the PSFCH resource. The period N may be set or predefined in units of slots.

[0064] In FIG. 13, the vertical axis corresponds to the frequency domain, and the horizontal axis corresponds to the time domain. The PSCCH may be placed in one symbol at the beginning of the slot, or in multiple symbols from the beginning, or in multiple symbols from a symbol other than the beginning. The PSFCH may be placed in one symbol at the end of the slot, or in multiple symbols at the end of the slot. Note that the above-mentioned "beginning of the slot" and "end of the slot" may omit consideration of symbols for AGC (Automatic Gain Control) and symbols for transmission / reception switching. That is, for example, when one slot is composed of 14 symbols, the "beginning of the slot" and the "end of the slot" may mean the beginning and end symbols, respectively, of 12 symbols excluding the beginning and end symbols. In the example shown in FIG. 13, three subchannels are set in the resource pool, and two PSFCHs are placed three slots after the slot in which the PSSCH is placed. The arrow from the PSSCH to the PSFCH shows an example of the PSFCH associated with the PSSCH.

[0065] When the HARQ response in the NR-V2X groupcast is groupcast option 2 that transmits ACK or NACK, it is necessary to determine the resources to be used for transmitting and receiving the PSFCH. As shown in FIG. 13, in step S401, terminal 20A, which is a transmitting terminal 20, executes groupcast to terminals 20B, 20C, and 20D, which are receiving terminals 20, via SL-SCH. In the following step S402, terminal 20B uses PSFCH#B, terminal 20C uses PSFCH#C, and terminal 20D uses PSFCH#D to transmit the HARQ response to terminal 20A. Here, as shown in the example of FIG. 13, 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. Note that the transmitting terminal 20 may know the number of receiving terminals 20 in the groupcast. Note that in groupcast option 1, only NACK is transmitted as the HARQ response, and ACK is not transmitted.

[0066] FIG. 14 is a diagram showing an example of sensing operation in LTE. When partial sensing is not set from a higher layer in the LTE sidelink, the terminal 20 selects resources and transmits as shown in FIG. 14. As shown in FIG. 14, the terminal 20 performs sensing in a sensing window in a resource pool. By sensing, the terminal 20 receives a resource reservation field included in an SCI transmitted from another terminal 20, and identifies available resource candidates in a resource selection window in the resource pool based on the field. Then, the terminal 20 randomly selects a resource from the available resource candidates. The resource selection window is a set of resources that are candidates for use and are set in the resource pool. The resource selection window may be called by other names, such as a setting related to resource selection, a target section for selecting resources, etc. The sensing window in LTE may be a section from a predetermined time point in the past before a trigger such as packet generation to just before the trigger. Sensing all the resources in the sensing window may be called full sensing. The sensing window may be called by other names indicating the section in which sensing is performed.

[0067] Also, as shown in FIG. 14, the resource pool configuration may have a period. For example, the period may be a period of 10240 milliseconds. FIG. 14 shows the period of the subframe t 0 SL From subframe t Tmax SL In this example, the resource pool is set to the period. The resource pool within the period may have an area set by, for example, a bitmap.

[0068] Also, as shown in FIG. 14, a transmission trigger in terminal 20 occurs in subframe n, and the priority of the transmission is p TX The terminal 20 receives the subframe t n-10×Pstep SL From subframe tn-1 SL In the sensing window up to the end of the period, for example, another terminal 20 receives priority p RX When an SCI is detected within the sensing window and the reference signal received power (RSRP) exceeds a threshold, the resource in the resource selection window corresponding to the SCI is excluded. When an SCI is detected within the sensing window and the RSRP is less than the threshold, the resource in the resource selection window corresponding to the SCI is not excluded. The threshold is, for example, a priority p TX and priority p RX Based on this, a threshold Th is set or defined for each resource in the sensing window. pTX,pRX may be also possible.

[0069] Also, subframe t shown in FIG. Z SL As such, resources in the resource selection window that are candidates for resource reservation information corresponding to resources in the sensing window that were not monitored, e.g., for transmission, are excluded.

[0070] Subframe n+T 1 From subframe n+T 2 In the resource selection window up to , the resources occupied by other UEs are identified, and the resources excluding the identified resources become available resource candidates. The set of available resource candidates is denoted as S A Then, S A If the resource selection window resource is less than 20% of the resources, the threshold Th set for each resource in the sensing window is pTX,pRX The threshold Th may be increased by 3 dB and resource identification may be performed again. pTX,pRX By increasing S and performing resource identification again, the number of resources that are not excluded because their RSRP is below the threshold may be increased. AMeasure the RSSI (Received signal strength indicator) of each resource in the set S B The set of candidate resources S B S until it is greater than or equal to 20% of the resource selection window. A The resource with the smallest RSSI in B The operation of adding to may be repeated.

[0071] The lower layer of the terminal 20 is S B The upper layer of the terminal 20 may report S B The terminal 20 may determine the resource to be used by performing random selection on the resources. The terminal 20 may perform sidelink transmission using the determined resource. Note that, after securing the resource once, the terminal 20 may select the resource for a predetermined number of times (e.g., C resel The resource may be used periodically without sensing for a certain period (times).

[0072] FIG. 15 is a diagram showing an example of partial sensing operation in LTE. When partial sensing is configured from a higher layer in LTE sidelink, the terminal 20 selects resources and transmits as shown in FIG. 15. As shown in FIG. 15, the terminal 20 performs partial sensing on a part of a sensing window in a resource pool. The resource on which partial sensing is performed may be called a sensing target, a sensing subject, a sensing subframe, or a sensing slot. With partial sensing, the terminal 20 receives a resource reservation field included in an SCI transmitted from another terminal 20, and identifies available resource candidates in a resource selection window in a resource pool based on the field. Then, the terminal 20 randomly selects a resource from the available resource candidates.

[0073] Also, as shown in FIG. 15, the resource pool configuration may have a period. For example, the period may be a period of 10240 milliseconds. FIG. 15 shows the period of the subframe t 0 SLFrom subframe t Tmax SL In this example, the resource pool is set to the range up to the period. The target area of ​​the resource pool within the period may be set by, for example, a bitmap.

[0074] As shown in FIG. 15, a transmission trigger in terminal 20 occurs in subframe n, and the priority of the transmission is p TX As shown in FIG. 1 From subframe n+T 2 Of these, subframe t y SL From subframe t y+Y-1 SL 15, the transmission trigger in terminal 20 occurs in subframe n, and the priority of the transmission is p TX Let us assume that.

[0075] The terminal 20 receives a subframe t y-k×Pstep SL From subframe t y+Y-k×Pstep-1 SL For example, in one or more sensing targets up to the first terminal 20, the other terminal 20 has a priority p RX It is possible to detect that the subframe t is transmitting. k may be, for example, a 10-bit bitmap. FIG. 15 shows an example in which the third and sixth bits of the bitmap k are set to "1", which indicates that partial sensing is being performed. That is, in FIG. 15, y-6×Pstep SL From subframe t y+Y-6×Pstep-1 SL Up to and subframe t y-3×Pstep SL From subframe t y+Y-3×Pstep-1 SL As described above, the i-th bit of bitmap k is set to the subframe t y-i×Pstep SL From subframe t y+Y-i×Pstep-1 SLThe sensing target may be up to 100 .mu.m.

[0076] where y is the index within the Y subframe, k is set in a 10-bit bitmap or is predefined, and P step However, when performing SL communication on DL and UL carriers, P step is (U / (D+S+U))*100ms, where U corresponds to the number of UL slots, D corresponds to the number of DL slots, and S corresponds to the number of special slots.

[0077] When an SCI is detected in one or more sensing targets and the RSRP is greater than a threshold, the resource in the resource selection window corresponding to the resource reservation field of the SCI is excluded. When an SCI is detected in a sensing target and the RSRP is less than a threshold, the resource in the resource selection window corresponding to the resource reservation field of the SCI is not excluded. The threshold is, for example, a priority p TX and priority p RX Based on this, a threshold Th is set or defined for each resource in the sensing window. pTX,pRX may be also possible.

[0078] As shown in FIG. 15, the interval [n+T 1 ,n+T 2 In the resource selection window in which the Y subframe is set among [ ], the terminal 20 identifies resources occupied by other UEs, and the resources excluding the identified resources become available resource candidates. Note that the Y subframes do not have to be consecutive. The set of available resource candidates is denoted as S A Then, S A If the resource selection window resource is less than 20% of the resources, the threshold Th set for each resource in the sensing window is pTX,pRX The threshold Th may be increased by 3 dB and resource identification may be performed again. pTX,pRX By increasing S and performing resource identification again, the number of resources that are not excluded because their RSRP is below the threshold may be increased. AMeasure the RSSI of each resource in and set S B The set of candidate resources S B S until it is greater than or equal to 20% of the resource selection window. A The resource with the smallest RSSI in B The operation of adding to may be repeated.

[0079] The lower layer of the terminal 20 is S B The upper layer of the terminal 20 may report S B The terminal 20 may determine the resource to be used by performing random selection on the resources. The terminal 20 may perform sidelink transmission using the determined resource. Note that, after securing the resource once, the terminal 20 may select the resource for a predetermined number of times (e.g., C resel The resource may be used periodically without sensing for a certain period (times).

[0080] FIG. 16 is a diagram showing an example of sensing operation in NR. In resource allocation mode 2, the terminal 20 selects a resource and performs transmission. As shown in FIG. 16, the terminal 20 performs sensing in a sensing window in a resource pool. By sensing, the terminal 20 receives a resource reservation field or a resource assignment field included in an SCI transmitted from another terminal 20, and identifies available resource candidates in a resource selection window in the resource pool based on the field. Then, the terminal 20 randomly selects a resource from the available resource candidates.

[0081] Also, as shown in FIG. 16, the resource pool configuration may have a period. For example, the period may be a period of 10240 milliseconds. FIG. 16 shows the time slot t 0 SL From slot t Tmax SLIn this example, the resource pool is set to the range up to the period 1. The resource pool in each period may have an area set by, for example, a bitmap.

[0082] Also, as shown in FIG. 16, a transmission trigger in terminal 20 occurs in slot n, and the priority of the transmission is p TX The terminal 20 receives the data in slot nT. 0 From slot nT proc,0 In the sensing window up to the slot immediately before the priority p RX When an SCI is detected within the sensing window and the Reference Signal Received Power (RSRP) exceeds a threshold, the resource in the resource selection window corresponding to the SCI is excluded. When an SCI is detected within the sensing window and the RSRP is less than the threshold, the resource in the resource selection window corresponding to the SCI is not excluded. The threshold is, for example, a priority p TX and priority p RX Based on this, a threshold Th is set or defined for each resource in the sensing window. pTX,pRX may be also possible.

[0083] Also, the slot t shown in FIG. m SL As such, resources in the resource selection window that are candidates for resource reservation information corresponding to resources in the sensing window that were not monitored, e.g., for transmission, are excluded.

[0084] Slot n+T 1 From slot n+T 2 In the resource selection window up to , the resources occupied by other UEs are identified, and the resources excluding the identified resources become available resource candidates. The set of available resource candidates is denoted as S A Then, S AIf the threshold Th is set for each resource in the sensing window, the pTX,pRX The threshold Th may be increased by 3 dB and resource identification may be performed again. pTX,pRX By increasing the number of resources that are not excluded because their RSRP is less than the threshold, the set of resource candidates S A may be set to be 20% or more of the resource selection window. A If the threshold Th is set for each resource in the sensing window, the pTX,pRX The operation of increasing the bandwidth by 3 dB and performing resource identification again may be repeated.

[0085] The lower layer of the terminal 20 is S A The upper layer of the terminal 20 may report S A The terminal 20 may perform a random selection on the resources to be used. The terminal 20 may perform sidelink transmission using the determined resources.

[0086] In the above-mentioned Figures 14, 15 and 16, the operation of the transmitting terminal 20 has been described, but the receiving terminal 20 may detect data transmission from another terminal 20 based on the results of sensing or partial sensing, and receive data from the other terminal 20.

[0087] In the NR Release 17 sidelink, power saving based on the above-mentioned random resource selection and partial sensing is being considered. For example, for power saving, the random resource selection and partial sensing of the sidelink in LTE Release 14 may be applied to resource allocation mode 2 of the NR Release 16 sidelink. A terminal 20 to which partial sensing is applied performs reception and sensing only in a specific slot within a sensing window.

[0088] In addition, in the NR Release 17 sidelink, enhanced Ultra Reliable Low Latency Communication (eURLLC) is being considered with inter-UE coordination as a baseline. For example, the terminal 20A may share information indicating a resource set with the terminal 20B, and the terminal 20B may take the information into consideration when selecting resources for transmission.

[0089] In resource allocation mode 2, in which terminal 20 autonomously selects resources, terminal 20 receives resource reservation information of other terminals 20 by sensing, and selects resources to be used for transmission based on the resource reservation information. Here, the information obtained by sensing is for the position of transmitting terminal 20.

[0090] On the other hand, whether the quality of the resource selected by the transmitting terminal 20 is actually good or bad (for example, whether there is no or small interference) also depends on the position of the receiving terminal 20. For example, there exists a hidden terminal problem in which a third terminal 20 that cannot be detected by the transmitting terminal 20 is in a position that causes interference to the receiving terminal 20.

[0091] Fig. 17 is a diagram showing an example (1) of D2D communication. As an example of the hidden terminal problem, as shown in Fig. 17, there is a case where a receiving terminal 20A is located between a transmitting terminal 20B that transmits using resource #A and a third terminal 20C that transmits using resource #A.

[0092] Fig. 18 is a diagram showing an example (2) of D2D communication. As an example of the hidden terminal problem, as shown in Fig. 18, when a third terminal 20C transmitting using resource A is located outside the line of sight of a transmitting terminal 20B transmitting using resource #A due to a building or the like, but is located within the line of sight of a receiving terminal 20A, the interference from terminal 20C is significantly different between terminal 20A and terminal 20B.

[0093] Therefore, a terminal 20 that has received resource reservation information reserving the same resource from different terminals 20 may transmit specific information to the specific terminal 20.

[0094] A terminal 20 that has received reservation information reserving the same resource from another terminal 20 may mean a terminal that satisfies at least one of the conditions shown in 1)-7) below. Note that a PC5-RRC connection refers to an RRC connection between terminals 20. Also, reserving the same resource may mean that, in the case of a reservation signal reserving multiple resources, at least one of the multiple resources is the same resource.

[0095] 1) Reservation information was received that reserves the same resource and all of the reservation information is addressed to the user's own terminal. 2) The destination of at least one piece of reservation information is the own terminal, and at least one piece of reservation information is not the own terminal, and reservation information for reserving the same resource is received. 3) Reservation information is received by unicast, groupcast or broadcast. 4) Reservation information is received from terminal 20 with which a PC5-RRC connection is established. 5) Reservation information for making a non-periodic reservation (e.g., a reservation based on a time resource assignment field) is received. 6) Reservation information for making periodic reservations is received according to the resource reservation period field. 7) At least one of the received RSRP and the priority of the received reservation information satisfies a predetermined condition. The above-mentioned predetermined condition 7) may be, for example, any of the following: a) A plurality of pieces of reservation information reserving the same resource are received, and the value or difference of the received RSRPs is greater or smaller than a predetermined value. b) A plurality of pieces of reservation information reserving the same resource are received, and the received RSRP of the reservation information with a higher priority is smaller than or is smaller by X dB or more than the received RSRP of the reservation information with a lower priority.

[0096] Fig. 19 is a diagram showing an example (1) of D2D communication in an embodiment of the present invention. As shown in Fig. 19, terminal 20B reserving resource #A transmits to terminal 20A, and terminal 20C reserving resource #A transmits to terminal 20A. That is, in Fig. 19, the above condition 1) is satisfied in which reservation information for reserving the same resource is received, with all reservation information destined for terminal 20A.

[0097] Fig. 20 is a diagram showing an example (2) of D2D communication in the embodiment of the present invention. As shown in Fig. 20, terminal 20B reserving resource #A transmits to terminal 20A, and terminal 20C reserving resource #A transmits to terminal D other than terminal 20A. That is, in Fig. 20, the destination related to at least one piece of reservation information is addressed to the own terminal, and the destination related to at least one piece of reservation information is not addressed to the own terminal, and the above condition 2) is satisfied when reservation information for reserving the same resource is received.

[0098] As described above, by defining a terminal 20 that has received reservation information reserving the same resource from a different terminal 20, transmissions in which the same resource is used can be avoided.

[0099] A terminal 20 that has received resource reservation information reserving the same resource from another terminal 20 may transmit specific information to the specific terminal 20 that is determined based on at least one of the following 1) to 12).

[0100] 1) At least one terminal 20 among the terminals 20 that transmitted the resource reservation information. 2) N-1 terminals 20 out of the N terminals 20 that transmitted the resource reservation information.

[0101] 3) Terminal 20 determined based on the destination related to the resource reservation information. Fig. 21 is a diagram showing an example (3) of D2D communication in an embodiment of the present invention. For example, specific information may be transmitted to terminal 20B that transmitted resource reservation information whose destination related to the resource reservation information includes sensed terminal 20A shown in Fig. 21. Also, specific information may be transmitted to terminal 20C that transmitted resource reservation information whose destination related to the resource reservation information is a destination (e.g. terminal 20D) that does not include sensed terminal 20A shown in Fig. 21.

[0102] 4) A terminal 20 determined based on a PC5-RRC connection. For example, among the terminals 20 that have transmitted the resource reservation information, a terminal 20 for which a PC5-RRC connection has been established with the sensed terminal 20. Also, for example, among the terminals 20 that have transmitted the resource reservation information, a terminal 20 for which a PC5-RRC connection has not been established with the sensed terminal 20.

[0103] 5) A terminal 20 determined based on the periodicity of a reservation. For example, a terminal 20 that has made a periodic reservation using the resource reservation information (for example, a reservation using a resource reservation period field). Also, a terminal 20 that has made a non-periodic reservation using the resource reservation information (for example, a reservation using a time resource allocation field). Also, a terminal 20 that has made a reservation using a period that is smaller than a value determined based on a specific condition.

[0104] 6) A terminal 20 determined based on priority, for example, a terminal 20 that has transmitted a reservation with a low priority related to the resource reservation information.

[0105] 7) A terminal 20 determined based on a packet delay budget (PDB). For example, a terminal 20 that has performed a transmission with a large PDB of a transport block related to the resource reservation information. Also, for example, a terminal 20 that has performed a transmission with a large remaining time until the PDB of a transport block related to the resource reservation information.

[0106] 8) A terminal 20 determined based on the number of reserved resources. For example, a terminal 20 having a large number of reserved resources according to the resource reservation information.

[0107] 9) A terminal 20 determined based on the received RSRP related to the resource reservation information. For example, a terminal 20 for which the received RSRP related to the resource reservation information is large or small.

[0108] 10) A terminal 20 determined based on the cast type of the resource reservation information, for example, a terminal 20 in which the resource reservation information is a reservation related to broadcast transmission.

[0109] 11) All terminals 20 that have transmitted the resource reservation information. 12) All terminals 20. For example, the sensing terminals 20 may broadcast certain information.

[0110] In addition, when at least one terminal 20 is identified among the terminals 20 shown in 3)-12) above, and the number of identified terminals 20 does not satisfy 1) or 2) above, further addition or deletion of the specific terminal 20 may be performed based on the terminal implementation.

[0111] As described above, by defining a terminal 20 that transmits specific information from a terminal 20 that has received reservation information reserving the same resources from a different terminal 20, transmissions that use the same resources can be avoided.

[0112] A terminal 20 that has received resource reservation information reserving the same resource from another terminal 20 may transmit to the specific terminal 20 specific information as shown in at least one of the following 1)-6).

[0113] 1) Information indicating that a collision has been detected. 2) Information indicating that a resource change is recommended or requested. Note that the recommendation means that the terminal 20 that has received the information does not have to comply with the information, and the request means that the terminal 20 that has received the information must comply with the information. Fig. 22 is a diagram showing an example (4) of D2D communication in the embodiment of the present invention. As shown in Fig. 22, the terminal 20A may transmit information requesting a resource change to the terminal 20C that reserves a transmission to the terminal 20D other than the terminal 20A that performed the sensing.

[0114] 3) Information that recommends or requests that resources not be used. 4) Recommending or requesting a change in transmission power. The difference in transmission power from the signal related to the reservation may be signaled, or the absolute value of the transmission power may be signaled.

[0115] 5) Information indicating a target resource. For example, a slot index and / or an offset may be notified, and if the reservation is periodic, the number of the resource may be notified. 6) Information indicating a value or range of priority to be transmitted using the resource. For example, it may be notified that only transmission of a priority value equal to or less than X is possible. The information may be transmitted by broadcast.

[0116] The method of transmitting the specific information shown in 1)-6) above may be the method shown in 1)-3) below.

[0117] 1) Physical layer signaling, which may be, for example, SCI, PSCCH, S-SSB, PSFCH or a newly defined channel. 2) Medium Access Control (MAC) signaling, which may be, for example, a MAC-Control element (CE). 3) RRC signaling, which may be, for example, a PC5-RRC message.

[0118] The terminal 20 that has received the specific information shown in 1)-6) above may perform the operation shown in 1)-5) below.

[0119] 1) Reselecting resources based on specific information. For example, as shown in Fig. 22, terminal 20C that has received specific information requesting a change in resources from sensed terminal 20A may newly select resource #B to be transmitted to terminals 20D below terminal 20A.

[0120] 2) Dropping resources based on specific information. 3) Varying the transmit power based on certain information. 4) Based on the specific information, the terminal performs an action implemented in the terminal. 5) Based on the specified information, perform a preemption action. Note that preemption may mean the following actions:

[0121] FIG. 23 is a sequence diagram showing an example of preemption in NR. FIG. 24 is a diagram showing an example of preemption in NR. In step S501, terminal 20 performs sensing in a sensing window. When terminal 20 performs a power saving operation, sensing may be performed in a predefined limited period. Next, terminal 20 identifies each resource in the resource selection window based on the sensing result to generate a set S of resource candidates. A Next, the terminal 20 determines a set of resource candidates S A Then, a resource set (r_0, r_1, . . . ) is selected from the list (S503).

[0122] In step S504, the terminal 20 calculates T(r_0)-T 3 At the timing, based on the sensing result, each resource in the resource selection window is identified again based on the priority to generate a set of resource candidates S AFor example, in r_1 shown in FIG. 24, an SCI transmitted from another terminal 20 is detected by re-sensing. When preemption is enabled, if the value prio_RX indicating the priority of the SCI transmitted from the other terminal 20 is lower than the value prio_TX indicating the priority of the transport block transmitted from the terminal itself, the terminal 20 determines the resource r_1 as S A The lower the value indicating the priority, the higher the priority. In other words, when the value prio_RX indicating the priority of the SCI transmitted from another terminal 20 is higher than the value prio_TX indicating the priority of the transport block transmitted from the terminal itself, the terminal 20 excludes the resource r_1 from the S A Do not exclude from.

[0123] In step S505, the terminal 20 A If resource r_i is not included in the resource set, r_i is removed from the resource set (S505), the resource set is updated, and preemption is terminated.

[0124] 22, the sensed terminal 20A may receive data transmitted from the terminal 20B in the resource #A. The sensed terminal 20A may receive data from terminals 20 that have not received reservation information other than the terminals 20B and 20C.

[0125] The embodiment of the present invention may be applied to an operation of a terminal 20 configuring or allocating transmission resources of another terminal 20. That is, the transmission resources of the other terminal 20 may be configured or allocated so as to satisfy the conditions of resource selection or resource allocation according to the embodiment of the present invention.

[0126] The above-described embodiment is not limited to V2X terminals, and may be applied to terminals that perform D2D communication.

[0127] The operations according to the above-described embodiment may be executed only in a specific resource pool. For example, the operations according to the above-described embodiment may be executed only in a resource pool that can be used by the terminal 20 of Release 17 or later.

[0128] The operations according to the above-described embodiments may be applied to any of the cases where the transmission is a groupcast, where the transmission is a unicast, or where the transmission is a broadcast.

[0129] According to the above-described embodiment, the terminal 20 can avoid transmission collisions in resources transmitted to the terminal 20 itself by transmitting specific information to other terminals 20 based on reservation information obtained by sensing.

[0130] That is, in direct communication between terminals, it is possible to improve the reliability of communication during autonomous resource selection.

[0131] (Device configuration) Next, a functional configuration example of the base station 10 and the terminal 20 that execute the processes and operations described above will be described. The base station 10 and the terminal 20 include functions for implementing the above-mentioned embodiments. However, the base station 10 and the terminal 20 may each include only a part of the functions in the embodiments.

[0132] <Base station 10> Fig. 25 is a diagram showing an example of the functional configuration of the base station 10. As shown in Fig. 25, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 25 is merely an example. The functional divisions and names of the functional units may be any as long as they can execute the operations related to the embodiment of the present invention.

[0133] The transmission unit 110 includes a function of generating a signal to be transmitted to the terminal 20 side and wirelessly transmitting the signal. The reception unit 120 includes a function of receiving various signals transmitted from the terminal 20 and obtaining information of, for example, a higher layer from the received signals. Further, the transmission unit 110 has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL reference signals, etc. to the terminal 20.

[0134] The setting unit 130 stores setting information set in advance and various setting information to be transmitted to the terminal 20 in a storage device and reads it out from the storage device as necessary. The content of the setting information is, for example, information related to the setting of D2D communication.

[0135] As described in the embodiment, the control unit 140 performs processing related to the setting for the terminal 20 to perform D2D communication. Further, the control unit 140 transmits the scheduling of D2D communication and DL communication to the terminal 20 via the transmission unit 110. Further, the control unit 140 receives information related to the HARQ response of D2D communication and DL communication from the terminal 20 via the reception unit 120. A functional unit related to signal transmission in the control unit 140 may be included in the transmission unit 110, and a functional unit related to signal reception in the control unit 140 may be included in the reception unit 120.

[0136] <Terminal 20> FIG. 26 is a diagram showing an example of the functional configuration of the terminal 20. As shown in FIG. 26, the terminal 20 includes a transmission unit 210, a reception unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in FIG. 26 is merely an example. As long as the operations according to the embodiments of the present invention can be executed, the functional division and the names of the functional units may be anything.

[0137] The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiver 220 wirelessly receives various signals and acquires a higher layer signal from the received physical layer signal. The receiver 220 also has a function of receiving an NR-PSS, an NR-SSS, an NR-PBCH, a DL / UL / SL control signal, a reference signal, or the like transmitted from the base station 10. For example, the transmitter 210 transmits a PSCCH (Physical Sidelink Control Channel), a PSSCH (Physical Sidelink Shared Channel), a PSDCH (Physical Sidelink Discovery Channel), a PSBCH (Physical Sidelink Broadcast Channel), or the like to another terminal 20 as D2D communication, and the receiver 220 receives the PSCCH, the PSSCH, the PSDCH, or the PSBCH, or the like, from the other terminal 20.

[0138] The setting unit 230 stores various setting information received from the base station 10 or the terminal 20 by the receiving unit 220 in a storage device, and reads the information from the storage device as necessary. The setting unit 230 also stores setting information that is set in advance. The content of the setting information is, for example, information related to the setting of D2D communication.

[0139] As described in the embodiment, the control unit 240 controls the D2D communication that establishes an RRC connection with another terminal 20. The control unit 240 also performs processing related to power saving operation. The control unit 240 also performs processing related to HARQ of the D2D communication and DL communication. The control unit 240 also transmits information related to the HARQ response of the D2D communication and DL communication to the other terminal 20 scheduled by the base station 10 to the base station 10. The control unit 240 may also schedule the D2D communication to the other terminal 20. The control unit 240 may also autonomously select resources to be used for the D2D communication from a resource selection window based on the result of sensing, or may perform reevaluation or preemption. The control unit 240 also performs processing related to power saving in transmission and reception of the D2D communication. The control unit 240 also performs processing related to inter-terminal cooperation in the D2D communication. A functional unit related to signal transmission in the control unit 240 may be included in the transmission unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the reception unit 220.

[0140] (Hardware configuration) The block diagrams (FIGS. 25 and 26) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically combined, or may be realized using two or more devices that are physically or logically separated and directly or indirectly connected (e.g., using wires, wirelessly, etc.) and these multiple devices. The functional blocks may be realized by combining the one device or the multiple devices with software.

[0141] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, mapping, assignment, etc. For example, a functional block (component) that performs the function of transmission is called a transmitting unit or a transmitter. In either case, as described above, there is no particular limitation on the method of realization.

[0142] For example, the base station 10, the terminal 20, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 27 is a diagram showing an example of a hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The above-mentioned base station 10 and the terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0143] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or more of the devices shown in the figure, or may be configured to exclude some of the devices.

[0144] Each function in the base station 10 and the terminal 20 is realized by loading a specific software (program) onto hardware such as a processor 1001, a memory device 1002, etc., so that the processor 1001 performs calculations, controls communications by the communication device 1004, and controls at least one of reading and writing of data in the memory device 1002 and the auxiliary memory device 1003.

[0145] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0146] Moreover, the processor 1001 reads out a program (program code), a software module, data, or the like from at least one of the auxiliary storage device 1003 and the communication device 1004 to the storage device 1002, and executes various processes according to the program. As the program, a program that causes a computer to execute at least a part of the operations described in the above-mentioned embodiment is used. For example, the control unit 140 of the base station 10 shown in FIG. 25 may be realized by a control program stored in the storage device 1002 and operated by the processor 1001. Also, for example, the control unit 240 of the terminal 20 shown in FIG. 26 may be realized by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed by two or more processors 1001 simultaneously or sequentially. The processor 1001 may be implemented by one or more chips. The program may be transmitted from a network via a telecommunication line.

[0147] The storage device 1002 is a computer-readable recording medium, and may be configured by at least one of, for example, a Read Only Memory (ROM), an Erasable Programmable ROM (EPROM), an Electrically Erasable Programmable ROM (EEPROM), a Random Access Memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The storage device 1002 can store a program (program code), software modules, etc. that are executable to implement a communication method according to an embodiment of the present disclosure.

[0148] The auxiliary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium including at least one of the storage device 1002 and the auxiliary storage device 1003.

[0149] The communication device 1004 is hardware (transmission and reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., in order to realize at least one of, for example, Frequency Division Duplex (FDD) and Time Division Duplex (TDD). For example, a transmission and reception antenna, an amplifier unit, a transmission and reception unit, a transmission line interface, etc. may be realized by the communication device 1004. The transmission and reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated from each other.

[0150] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0151] In addition, each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0152] 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 application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc., and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0153] (Summary of the embodiment) As described above, according to an embodiment of the present invention, a first terminal includes a receiving unit that receives first reservation information reserving a first resource from a second terminal and receives second reservation information reserving a second resource from a third terminal, a control unit that, when a destination related to the first reservation information is not the first terminal but a destination related to the second reservation information is the first terminal, identifies a terminal to which information regarding a collision between the first resource and the second resource is to be sent based on a first priority related to the first reservation information and a second priority related to the second reservation information, and a transmitting unit that transmits information regarding the collision to the identified terminal.

[0154] With the above configuration, the terminal 20 can avoid transmission collisions in resources transmitted to the terminal 20 by transmitting specific information to other terminals 20 based on reservation information obtained by sensing. That is, in direct communication between terminals, the reliability of communication during autonomous resource selection can be improved.

[0155] The control unit may detect the collision when a value of Reference Signal Received Power (RSRP) of the second terminal is greater than a predetermined value. The control unit may detect the collision when a difference between the RSRP of the second terminal and the RSRP of the third terminal is greater than a predetermined value.

[0156] The transmission unit may transmit the information regarding the collision via a Physical Sidelink Feedback Channel (PSFCH).

[0157] According to an embodiment of the present invention, the second terminal includes a transmitting unit that transmits first reservation information reserving a first resource, a receiving unit that receives information regarding a collision between the first resource and the second resource from the first terminal when the destination of the first reservation information is not the first terminal and the destination of the second reservation information reserving a second resource and transmitted from a third terminal is the first terminal, and a control unit that controls reselection of resources to be used for terminal-to-terminal communication based on the information regarding the collision.

[0158] According to an embodiment of the present invention, a third terminal includes a transmitting unit that transmits second reservation information reserving a second resource, a receiving unit that receives from the first terminal information regarding a collision between the first resource and the second resource when the destination of the first reservation information transmitted from the second terminal is not the first terminal and the destination of the second reservation information is the first terminal, and a control unit that controls reselection of resources to be used for terminal-to-terminal communication based on the information regarding the collision.

[0159] According to an embodiment of the present invention, a communication method executed by a first terminal includes the steps of receiving first reservation information reserving a first resource from a second terminal and receiving second reservation information reserving a second resource from a third terminal; if a destination related to the first reservation information is not the first terminal but a destination related to the second reservation information is the first terminal, identifying a terminal to which information regarding a collision between the first resource and the second resource is to be sent based on a first priority related to the first reservation information and a second priority related to the second reservation information; and transmitting information regarding the collision to the identified terminal.

[0160] With the above configuration, the terminal 20 can avoid transmission collisions in resources transmitted to the terminal 20 by transmitting specific information to other terminals 20 based on reservation information obtained by sensing. That is, in direct communication between terminals, the reliability of communication during autonomous resource selection can be improved.

[0161] (Supplementary embodiment) Although the embodiment of the present invention has been described above, the disclosed invention is not limited to such an embodiment, and those skilled in the art will understand various modifications, modifications, alternatives, replacements, and the like. Although the description has been given using specific numerical examples to facilitate understanding of the invention, unless otherwise specified, those numerical values ​​are merely examples and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention, and matters described in two or more items may be used in combination as necessary, and matters described in one item may be applied to matters described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operations of multiple functional units may be physically performed by one part, or the operations of one functional unit may be physically performed by multiple parts. The order of the processing procedures described in the embodiment may be changed as long as there is no contradiction. For convenience of the processing description, the base station 10 and the terminal 20 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. The software operated by the processor possessed by the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor possessed by the terminal 20 in accordance with an embodiment of the present invention may each be stored in a random access memory (RAM), flash memory, read only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

[0162] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination of these. Furthermore, the RRC signaling may be called an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0163] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), 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 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), and other suitable systems, and next-generation systems extended based on these. In addition, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A and 5G, etc.) may be applied.

[0164] The steps, sequences, flow charts, etc. of each aspect / embodiment described herein may be reordered unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0165] In this specification, a specific operation performed by the base station 10 may be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and other network nodes other than the base station 10 (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case in which there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (e.g., MME and S-GW).

[0166] The information or signals described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0167] The input and output information may be stored in a specific location (e.g., memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0168] In the present disclosure, the determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0169] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0170] Additionally, software, instructions, information, etc. may be transmitted or received over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using wired and / or wireless technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave, etc.), then these wired and / or wireless technologies are included within the definition of transmission media.

[0171] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0172] In addition, the terms described in this disclosure and the terms 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). Also, a signal may be a message. Also, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0173] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0174] In addition, the information, parameters, etc. described in the present disclosure may be represented using absolute values, may be represented using relative values ​​from a predetermined value, or may be represented using other corresponding information. For example, a radio resource may be indicated by an index.

[0175] The names used for the above-mentioned parameters are not limiting in any way. Moreover, the formulas using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not limiting in any way.

[0176] In the present disclosure, terms such as "base station (BS)", "radio 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", "component carrier", etc. may be used interchangeably. A base station may also be referred to by terms such as a macro cell, a small cell, a femto cell, a pico cell, etc.

[0177] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or a base station subsystem that provides communication services in this coverage.

[0178] In this disclosure, the terms "Mobile Station (MS)", "user terminal", "User Equipment (UE)", "terminal", etc. may be used interchangeably.

[0179] A mobile station may also be referred to by those skilled in the art as a 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 suitable terminology.

[0180] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a moving body, the moving body itself, etc. The moving body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned moving body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may include a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0181] Furthermore, the base station in the present disclosure may be read as a user terminal. For example, each aspect / embodiment of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between a plurality of terminals 20 (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, an uplink channel, a downlink channel, etc. may be read as a side channel.

[0182] Similarly, a user terminal in the present disclosure may be read as a base station. In this case, the base station may be configured to have the functions of the above-mentioned user terminal.

[0183] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in a memory), and the like. In addition, "judgment" and "decision" can include considering resolving, selecting, choosing, establishing, comparing, etc., to be a "judgment" or "decision." In other words, "judgment" and "decision" can include considering some action to be a "judgment" or "decision." In addition, "judgment" can be interpreted as "assuming," "expecting," "considering," etc.

[0184] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." 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, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0185] The reference signal may be abbreviated as RS (Reference Signal) and may be called a pilot depending on the applicable standard.

[0186] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0187] Any reference to an element using a designation such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

[0188] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0189] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Further, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0190] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0191] The numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as, for example, at least one of a subcarrier spacing (SCS), a bandwidth, a symbol length, a cyclic prefix length, a transmission time interval (TTI), a number of symbols per TTI, a radio frame structure, a particular filtering operation that the transceiver performs in the frequency domain, a particular windowing operation that the transceiver performs in the time domain, etc.

[0192] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) in the time domain. A slot may be a time unit based on numerology.

[0193] A slot may include multiple minislots. Each minislot may be composed of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may be composed of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0194] A radio frame, a subframe, a slot, a minislot, and a symbol each represent a time unit for transmitting a signal. The radio frame, the subframe, the slot, the minislot, and the symbol may each be referred to by a different name.

[0195] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in the existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit expressing the TTI may be called a slot, a minislot, or the like, instead of a subframe.

[0196] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0197] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) in which a transport block, a code block, a code word, etc. are actually mapped may be shorter than the TTI.

[0198] In addition, when one slot or one minislot is called TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit of scheduling. Also, the number of slots (minislots) constituting the minimum time unit of scheduling may be controlled.

[0199] A TTI having a time length of 1 ms may be 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 slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a minislot, a subslot, a slot, etc.

[0200] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length exceeding 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0201] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of the numerology, for example, 12. The number of subcarriers included in an RB may be determined based on the numerology.

[0202] In addition, the time domain of the RB may include one or more symbols and may be one slot, one minislot, one subframe, or one TTI in length. Each of one TTI, one subframe, etc. may be composed of one or more resource blocks.

[0203] Note that one or more RBs may be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, or the like.

[0204] 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.

[0205] A Bandwidth Part (BWP), which may also be referred to as a fractional bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a numerology on a carrier, where the common RBs may be identified by an index of the RBs relative to a common reference point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0206] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). For the terminal 20, one or more BWPs may be set within one carrier.

[0207] At least one of the configured BWPs may be active, and the terminal 20 may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell", "carrier", and the like in this disclosure may be replaced with "BWP".

[0208] The above-mentioned structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0209] In this disclosure, where articles have been added due to translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0210] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0211] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched according to execution. In addition, notification of predetermined information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the predetermined information).

[0212] In the present disclosure, the first terminal is an example of the terminal 20C, and the second terminal is an example of the terminal 20B.

[0213] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure. [Explanation of symbols]

[0214] 10 base station 110 Transmitter 120 Receiving unit 130 Setting section 140 Control section 20 Terminals 210 Transmitter 220 Receiving unit 230 Setting section 240 Control Unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output device

Claims

1. A first terminal, a receiving unit that receives first reservation information for reserving a first resource from a second terminal and receives second reservation information for reserving a second resource from a third terminal; a control unit that, when a destination related to the first reservation information is not the first terminal but a destination related to the second reservation information is the first terminal, specifies a terminal to which information related to the collision between the first resource and the second resource is to be transmitted based on a first priority related to the first reservation information and a second priority related to the second reservation information; A first terminal comprising: a transmitter that transmits information regarding the collision to the identified terminal.

2. The first terminal according to claim 1 , wherein the control unit detects the collision when a reference signal received power (RSRP) value of the second terminal is greater than a predetermined value.

3. The first terminal according to claim 1 , wherein the control unit detects the collision when a difference between an RSRP of the second terminal and an RSRP of the third terminal is greater than a predetermined value.

4. The first terminal according to claim 1 , wherein the transmission unit transmits the information about the collision via a Physical Sidelink Feedback Channel (PSFCH).

5. a second terminal, a transmitting unit that transmits first reservation information for reserving a first resource; a receiving unit that receives, when a destination related to the first reservation information is not the first terminal and a destination related to the second reservation information for reserving a second resource and transmitted from a third terminal is the first terminal, information related to a collision between the first resource and the second resource from the first terminal; A control unit that controls reselection of resources to be used for terminal-to-terminal communication based on the information regarding the collision.

6. a third terminal, a transmitting unit that transmits second reservation information for reserving a second resource; a receiving unit that receives, when a destination of the first reservation information for reserving a first resource is not the first terminal and a destination of the second reservation information is the first terminal, from the first terminal, information regarding a collision between the first resource and the second resource; A control unit that controls reselection of resources to be used for terminal-to-terminal communication based on the information related to the collision.

7. 1. A communication method performed by a first terminal, comprising: receiving first reservation information reserving a first resource from a second terminal and receiving second reservation information reserving a second resource from a third terminal; When a destination related to the first reservation information is not the first terminal but a destination related to the second reservation information is the first terminal, specifying a terminal to which information related to the collision between the first resource and the second resource is to be transmitted based on a first priority related to the first reservation information and a second priority related to the second reservation information; and transmitting information about the collision to the identified terminal.

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