Terminals, communication systems, and communication methods

Abstract

This terminal has a reception unit for receiving signals from a first terminal and a second terminal in a resource pool, a control unit for detecting that a first reserved resource based on the signal received from the first terminal and a second reserved resource based on the signal received from the second terminal overlap, and a transmission unit for transmitting information pertaining to resource selection to the first terminal via a channel that issues notification of a collision when an overlap is detected by the control unit, the control unit determining, when the first reserved resource is a plurality of resources, whether or not to transmit the information pertaining to resource selection by a channel that issues notification of a collision and that is associated with one of the plurality of resources.

Description

Technical Field

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

Background Art

[0002] In LTE (Long Term Evolution) and successor systems of LTE (for example, LTE-A (LTE Advanced), NR (New Radio) (also referred to as 5G)), D2D (Device to Device) technology in which terminals communicate directly without going through a base station has been studied (for example, Non-Patent Document 1).

[0003] D2D reduces traffic between a terminal and a base station and enables communication between terminals even when the base station becomes incommunicable during a disaster or the like. In 3GPP (Third Generation Partnership Project), D2D is referred to as "sidelink", but in this specification, the more general term D2D is used. However, sidelink is also used as necessary in the description of the embodiments described later.

[0004] D2D communication is roughly classified into D2D discovery (also referred to as D2D discovery) for discovering other communicable terminals and D2D communication (also referred to as D2D direct communication, D2D communication, direct communication between terminals, etc.) for directly communicating between terminals. Hereinafter, when not particularly distinguishing between D2D communication, D2D discovery, etc., it is simply referred to as D2D. Also, a signal transmitted and received by D2D is referred to as a D2D signal. Various use cases of services related to V2X (Vehicle to Everything) in NR have been studied (for example, Non-Patent Document 2).

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] As an enhancement of NR side links, enhanced Ultra Reliable Low Latency Communication (eURLLC) is being considered. For example, in Resource Allocation Mode 2 where a terminal autonomously selects resources, terminal 20A shares information indicating a resource set with terminal 20B, and terminal 20B considers this information in resource selection for transmission, thereby improving the reliability of communication and reducing latency.

[0007] On the other hand, in Resource Allocation Mode 2, when the transmitting terminal performs sensing, for example, if there are other terminals out of sight from the transmitting terminal, the quality of resources at the receiving terminal may be significantly different from the quality based on the result of the transmitting terminal sensing the resource.

[0008] The present invention has been made in view of the above points, and aims to improve the reliability of communication during autonomous resource selection in direct communication between terminals.

Means for Solving the Problems

[0009] According to the disclosed technology, the device includes: a receiving unit that receives first control information from a second terminal, including information about reserved resources for a data channel in direct terminal-to-terminal communication, and a receiving unit that receives second control information from a third terminal, including information about reserved resources for a data channel in direct terminal-to-terminal communication; a control unit that detects a collision of the reserved resources based on the first and second control information; and a transmitting unit that transmits a feedback channel containing the reserved resource collision information to the second terminal based on a first timing or a second timing, wherein the first timing is based on a first time from receiving the first control information to transmitting the feedback channel, and the second timing is based on the second terminal receiving the feedback channel Processing time required to perform the corresponding action after receiving the message. A terminal is provided that is based on [a certain principle]. [Effects of the Invention]

[0010] According to the disclosed technology, the reliability of communication during autonomous resource selection in direct terminal-to-terminal communication can be improved. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram to explain V2X. [Figure 2] This is a diagram illustrating an example of a V2X transmission mode (1). [Figure 3] This is a diagram illustrating an example of a V2X transmission mode (2). [Figure 4] This is a diagram illustrating an example of a V2X transmission mode (3). [Figure 5] This is a diagram illustrating an example of a V2X transmission mode (4). [Figure 6] This is a diagram illustrating an example of a V2X transmission mode (5). [Figure 7] This is a diagram illustrating an example of a V2X communication type (1). [Figure 8] This is a diagram illustrating an example of a V2X communication type (2). [Figure 9] This is a diagram illustrating example (3) of V2X communication types. [Figure 10] This is a sequence diagram showing an example of V2X operation (1). [Figure 11] This is a sequence diagram showing an example of V2X operation (2). [Figure 12] This is a sequence diagram showing an example of V2X operation (3). [Figure 13] This is a sequence diagram showing an example of V2X operation (4). [Figure 14] This figure shows an example of sensing operation. [Figure 15] This is a flowchart illustrating an example of preemption behavior. [Figure 16] This figure shows an example of preemption behavior. [Figure 17] This figure shows an example of partial sensing operation. [Figure 18] This is a diagram illustrating an example of communication conditions (1). [Figure 19] This is a diagram illustrating example (2) of the communication status. [Figure 20] This is a diagram illustrating example (3) of the communication status. [Figure 21] This is a diagram illustrating example (4) of the communication status. [Figure 22] This is a diagram illustrating example (5) of the communication status. [Figure 23] This is a sequence diagram illustrating an example of inter-UE coordination in an embodiment of the present invention. [Figure 24] This figure illustrates an example (1) of inter-UE cooperation in an embodiment of the present invention. [Figure 25] This figure illustrates an example (2) of inter-UE cooperation in an embodiment of the present invention. [Figure 26] This figure illustrates an example (3) of inter-UE cooperation in an embodiment of the present invention. [Figure 27] This figure illustrates an example (4) of inter-UE cooperation in an embodiment of the present invention. [Figure 28]This figure illustrates an example (5) of inter-UE cooperation in an embodiment of the present invention. [Figure 29] This figure illustrates an example (6) of inter-UE cooperation in an embodiment of the present invention. [Figure 30] This figure illustrates an example (7) of inter-UE cooperation in an embodiment of the present invention. [Figure 31] This figure shows an example of the functional configuration of the base station 10 in an embodiment of the present invention. [Figure 32] This figure shows an example of the functional configuration of terminal 20 in an embodiment of the present invention. [Figure 33] This figure shows an example of the hardware configuration of a base station 10 or terminal 20 in an embodiment of the present invention. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are examples, and the embodiments to which the present invention is applied are not limited to those described below.

[0013] In the operation of the wireless communication system according to the embodiments of the present invention, existing technologies may be used as appropriate. However, such existing technologies include, for example, existing LTE, but are not limited to existing LTE. Furthermore, the term "LTE" as used herein has a broad meaning that includes LTE-Advanced and LTE-Advanced and later methods (e.g., NR), or wireless LAN (Local Area Network), unless otherwise specified.

[0014] Furthermore, in the embodiments of the present invention, the duplex method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or any other method (for example, a Flexible Duplex).

[0015] Furthermore, in the embodiments of the present invention, "configuring" wireless parameters may mean that predetermined values ​​are pre-configured, or that wireless parameters notified from the base station 10 or terminal 20 are configured.

[0016] Figure 1 is a diagram illustrating V2X. 3GPP is considering and working on specifications to realize V2X (Vehicle to Everything) or eV2X (enhanced V2X) by extending D2D functionality. As shown in Figure 1, V2X is a part of ITS (Intelligent Transport Systems) and is a general term encompassing V2V (Vehicle to Vehicle), which refers to communication between vehicles; V2I (Vehicle to Infrastructure), which refers to communication between vehicles and roadside units (RSUs) installed along the roadside; V2N (Vehicle to Network), which refers to communication between vehicles and ITS servers; and V2P (Vehicle to Pedestrian), which refers to communication between vehicles and mobile terminals carried by pedestrians.

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

[0018] Regarding LTE or NR V2X, it is anticipated that future considerations will extend beyond 3GPP specifications. For example, it is expected that considerations will be given to ensuring interoperability, reducing costs through the implementation of higher layers, methods for using or switching between multiple RATs (Radio Access Technologies), compliance with regulations in various countries, and methods for data acquisition, distribution, database management, and utilization of LTE or NR V2X platforms.

[0019] While the embodiments of the present invention primarily envision a configuration in which the communication device is mounted on a vehicle, the embodiments of the present invention are not limited to this configuration. For example, the communication device may be a terminal held by a person, a device mounted on a drone or aircraft, or a base station, RSU, relay station (relay node), terminal with scheduling capabilities, etc.

[0020] Furthermore, SL (Sidelink) may be distinguished from UL (Uplink) or DL ​​(Downlink) based on any one or a combination of the following 1)-4). Also, SL may have other names. 1) Resource allocation in the time domain 2) Resource allocation in the frequency domain 3) Reference synchronization signals (including SLSS (Sidelink Synchronization Signal)) 4) Reference signal used for path loss measurement for transmit power control

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

[0022] In LTE's Downlink Service Line (SL), Mode 3 and Mode 4 are defined for allocating SL resources to terminal 20. In Mode 3, transmission resources are dynamically allocated via DCI (Downlink Control Information) sent from base station 10 to terminal 20. Semi-Persistent Scheduling (SPS) is also possible in Mode 3. In Mode 4, terminal 20 autonomously selects transmission resources from the resource pool.

[0023] In the embodiments of the present invention, the term "slot" may be interpreted as a symbol, mini-slot, subframe, wireless frame, or TTI (Transmission Time Interval). Furthermore, in the embodiments of the present invention, the term "cell" may be interpreted as a cell group, carrier component, BWP, resource pool, resource, RAT (Radio Access Technology), system (including wireless LAN), etc.

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

[0025] Figure 2 is a diagram illustrating an example of a V2X transmission mode (1). In the sidelink communication transmission mode shown in Figure 2, in step 1, the base station 10 transmits the sidelink scheduling to terminal 20A. Subsequently, terminal 20A transmits the PSCCH (Physical Sidelink Control Channel) and PSSCH (Physical Sidelink Shared Channel) to terminal 20B based on the received scheduling (step 2). The sidelink communication transmission mode shown in Figure 2 may also be called sidelink transmission mode 3 in LTE. In sidelink transmission mode 3 in LTE, Uu-based sidelink scheduling is performed. Uu is the radio interface between UTRAN (Universal Terrestrial Radio Access Network) and UE (User Equipment). The sidelink communication transmission mode shown in Figure 2 may also be called sidelink transmission mode 1 in NR.

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

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

[0028] Figure 5 is a diagram illustrating an example of a V2X transmission mode (4). In the sidelink communication transmission mode shown in Figure 5, in step 0, the sidelink resource pattern is transmitted from the base station 10 to terminal 20A via RRC (Radio Resource Control) settings, or is pre-configured. Subsequently, terminal 20A transmits PSSCH to terminal 20B based on the resource pattern (step 1). The sidelink communication transmission mode shown in Figure 5 may also be called the sidelink transmission mode 2c in NR.

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

[0030] Figure 7 is a diagram illustrating an example of a V2X communication type (1). The sidelink communication type shown in Figure 7 is unicast. Terminal 20A transmits PSCCH and PSSCH to Terminal 20. In the example shown in Figure 7, Terminal 20A unicasts to Terminal 20B and also unicasts to Terminal 20C.

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

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

[0033] Furthermore, it is anticipated that NR-V2X will support HARQ (Hybrid automatic repeat request) for sidelink unicast and groupcast. In addition, NR-V2X will define SFCI (Sidelink Feedback Control Information) that includes HARQ responses. Moreover, it is being considered that SFCI will be transmitted via PSFCH (Physical Sidelink Feedback Channel).

[0034] Note that the following explanation assumes the use of PSFCH for transmitting HARQ-ACK over a sidelink, but this is just one example. For example, you may use PSCCH to transmit HARQ-ACK over a sidelink, or PSSCH, or any other channel to transmit HARQ-ACK over a sidelink.

[0035] In the following, for convenience, all information reported by terminal 20 in HARQ will be referred to as HARQ-ACK. This HARQ-ACK may also be called HARQ-ACK information. More specifically, the codebook applied to the HARQ-ACK information reported from terminal 20 to base station 10, etc., will be called the HARQ-ACK codebook. The HARQ-ACK codebook defines the bit sequence of the HARQ-ACK information. In addition to ACK, NACK is also transmitted with "HARQ-ACK".

[0036] Figure 10 is a sequence diagram showing an example of V2X operation (1). As shown in Figure 10, the wireless communication system according to the embodiment of the present invention may have terminals 20A and 20B. In reality, there are many user devices, but Figure 10 shows terminals 20A and 20B as examples.

[0037] Hereafter, unless otherwise specified, terminals 20A, 20B, etc., will simply be referred to as "terminal 20" or "user device." Figure 10 shows an example where both terminal 20A and terminal 20B are within the cell coverage, but the operation in the embodiment of the present invention can also be applied when terminal 20B is outside the coverage.

[0038] As described above, in this embodiment, terminal 20 is, for example, a device mounted on a vehicle such as an automobile, and has cellular communication functionality as a UE in LTE or NR, as well as side-link functionality. Terminal 20 may be a general mobile terminal (such as a smartphone). Alternatively, terminal 20 may be an RSU. The RSU may be a UE-type RSU with UE functionality, or a gNB-type RSU with base station functionality.

[0039] Furthermore, the terminal 20 does not need to be a single-casing device; for example, even if various sensors are distributed throughout the vehicle, the device including these various sensors may be considered the terminal 20.

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

[0041] The base station 10 has the functionality of a cellular communication base station in LTE or NR, and functions to enable communication for the terminal 20 in this embodiment (e.g., resource pool setting, resource allocation, etc.). The base station 10 may also 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 the terminal 20 for SL or UL may be OFDMA, SC-FDMA, or other signal waveforms.

[0043] In step S101, terminal 20A autonomously selects resources to be used for PSCCH and PSSCH from a resource selection window having a predetermined period. The resource selection window may be set from base station 10 to terminal 20. Here, the predetermined period of the resource selection window may be defined by terminal implementation conditions such as processing time or maximum allowable packet delay time, or it 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, terminal 20A transmits SCI (Sidelink Control Information) via PSCCH and / or PSSCH using the resources autonomously selected in step S101, and also transmits SL data via PSSCH. For example, terminal 20A may transmit PSCCH using the same time resources as at least a portion of the time resources of PSSCH, and using frequency resources adjacent to the frequency resources of PSSCH.

[0045] Terminal 20B receives SCI (PSCCH and / or PSSCH) and SL data (PSSCH) transmitted from terminal 20A. The received SCI may include information about the PSFCH resource that terminal 20B uses to send a HARQ-ACK for receiving the data. Terminal 20A may also include information about an autonomously selected resource in the SCI and transmit it.

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

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

[0048] If HARQ control with HARQ feedback is not performed, steps S104 and S105 do not need to be performed.

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

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

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

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

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

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

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

[0056] Furthermore, in step S301, it is assumed that the base station 10 also transmits a DCI for DL ​​scheduling (which may also be called DL allocation) to the terminal 20A via PDCCH. Hereafter, for convenience, the DCI for DL ​​scheduling will be referred to as DL scheduling DCI. Upon receiving the DL scheduling DCI, the terminal 20A receives DL data via PDSCH using the resources specified in the DL scheduling DCI.

[0057] In steps S302 and S303, terminal 20A transmits SCI (Sidelink Control Information) via PSCCH and / or PSSCH using the resources specified in the SL scheduling DCI, and also transmits SL data via PSSCH. Note that only the resources for PSSCH may be specified in the SL scheduling DCI. In this case, for example, terminal 20A may transmit PSCCH using the same time resources as at least a portion of the time resources for PSSCH, and using frequency resources adjacent to the frequency resources for PSSCH.

[0058] Terminal 20B receives SCI (PSCCH and / or PSSCH) and SL data (PSSCH) transmitted from terminal 20A. The SCI received via PSCCH and / or PSSCH contains information about the PSFCH resource that terminal 20B uses to send a HARQ-ACK for 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 retrieves the resource information from the DL scheduling DCI or SL scheduling DCI and includes it in the SCI. Alternatively, the DCI transmitted from the base station 10 may not include the resource information, and the terminal 20A may autonomously include the resource information in the SCI and transmit it.

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

[0061] In step S305, terminal 20A transmits a HARQ-ACK using the PUCCH (Physical uplink control channel) resource specified by the DL scheduling DCI (or SL scheduling DCI) at a timing (e.g., a slot-based timing) specified by the DL scheduling DCI (or SL scheduling DCI), and 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 terminal 20B or a PSFCH that was not received, and a HARQ-ACK for DL ​​data. However, if there is no allocation of DL data, the HARQ-ACK for DL ​​data will not be included. In NR Rel.16, the codebook of the HARQ-ACK does not include a HARQ-ACK for DL ​​data.

[0062] If HARQ control with HARQ feedback is not performed, steps S304 and / or S305 may not be performed.

[0063] Figure 13 is a sequence diagram showing an example of V2X operation (4). As mentioned above, in the NR sidelink, it is supported that the HARQ response is transmitted in PSFCH format. The PSFCH format can be the same as, for example, the PUCCH (Physical Uplink Control Channel) format 0. That is, the PSFCH format may be a sequence-based format in which the PRB (Physical Resource Block) size is 1 and ACK and NACK are identified by the difference in sequence and / or cyclic shift. The PSFCH format is not limited to this. The PSFCH resource may be placed in the symbol at the end of the slot or in multiple symbols at the end. In addition, a period N is set or predetermined for the PSFCH resource. The period N may be set or predetermined on a per-slot basis.

[0064] In Figure 13, the vertical axis corresponds to the frequency domain and the horizontal axis corresponds to the time domain. A PSCCH may be placed in the first symbol of a slot, in multiple symbols from the beginning, or in multiple symbols from symbols other than the first. A PSFCH may be placed in the last symbol of a slot, or in multiple symbols at the end of a 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 transmit / receive switching. That is, for example, if one slot consists of 14 symbols, "beginning of the slot" and "end of the slot" may mean the first and last symbols, respectively, among the 12 symbols excluding the first and last symbols. In the example shown in Figure 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 PSSCH to PSFCH shows an example of a PSFCH associated with a PSSCH.

[0065] If the NR-V2X group cast uses group cast option 2, where the HARQ response is either an ACK or a NACK, it is necessary to determine the resources to be used for sending and receiving PSFCH. As shown in Figure 13, in step S401, the transmitting terminal 20, terminal 20A, performs a group cast via SL-SCH to the receiving terminals 20, terminals 20B, 20C, and 20D. In the following step S402, terminal 20B uses PSFCH#B, terminal 20C uses PSFCH#C, and terminal 20D uses PSFCH#D to send the HARQ response to terminal 20A. Here, as shown in the example in Figure 13, if 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. The transmitting terminal 20 may also know the number of receiving terminals 20 in the group cast. In group cast option 1, only a NACK is sent as the HARQ response; an ACK is not sent.

[0066] Figure 14 shows an example of sensing operation in NR. In Resource allocation mode 2, terminal 20 selects and transmits a resource. As shown in Figure 14, terminal 20 performs sensing in the sensing window within the resource pool. Through sensing, terminal 20 receives resource reservation or resource assignment fields included in the SCI transmitted from other terminals 20, and identifies available resource candidates in the resource selection window within the resource pool based on these fields. Subsequently, terminal 20 randomly selects a resource from the available resource candidates.

[0067] Furthermore, as shown in Figure 14, the resource pool settings may have a period. For example, the period may be a duration of 10240 milliseconds. Figure 14 shows slot t0 SLfrom slot t Tmax-1 SL This is an example where the period from this to slot t is set as a resource pool. The resource pool within each period may have its area set, for example, by a bitmap.

[0068] Also, as shown in FIG. 14, the transmission trigger in terminal 20 occurs in slot n, and the priority of this transmission is p TX Let's assume so. Terminal 20, in the sensing window from slot n - T0 to the slot immediately before slot n - T proc,0 can detect, for example, that another terminal 20 is performing a transmission with priority p RX . If an SCI is detected within the sensing window and the RSRP (Reference Signal Received Power) exceeds the threshold, the resources within the resource selection window corresponding to the SCI are excluded. Also, if an SCI is detected within the sensing window and the RSRP is less than the threshold, the resources within the resource selection window corresponding to the SCI are not excluded. The threshold may be, for example, a threshold Th TX set or defined for each resource within the sensing window based on priority p RX and priority p pTX,pRX .

[0069] Also, as shown in slot t in FIG. 14 m SL , for example, for transmission, the resources within the resource selection window that are candidates for resource reservation information corresponding to the resources in the sensing window that were not monitored are excluded.

[0070] As shown in FIG. 14, for the resource selection window from slot n + T1 to slot n + T2, the resources occupied by other UEs are identified, and the resources after excluding those are candidates for available resources. Let the set of available resource candidates be S A Then S AIf the resource selection window is less than 20%, the threshold Th is set for each resource in the sensing window. pTX,pRX You can increase the threshold Th by 3dB and perform resource identification again. pTX,pRX By increasing the value and performing resource identification again, the number of resources that are not excluded because the RSRP is below the threshold is increased, resulting in a set of resource candidates S. A It may also be necessary to ensure that it occupies 20% or more of the resource selection window. A If the resource selection window is less than 20%, the threshold Th is set for each resource in the sensing window. pTX,pRX The process of increasing the value by 3dB and re-identifying the resource may be repeated.

[0071] The lower layer of terminal 20 is S A This may be reported to the upper layer. The upper layer of terminal 20 is S A A random selection may be performed to determine which resource to use. Terminal 20 may then use the determined resource to perform a sidelink transmission.

[0072] Although Figure 14 above illustrates the operation of the transmitting terminal 20, 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 that other terminal 20.

[0073] Figure 15 is a flowchart showing an example of preemption in NR. Figure 16 is a diagram showing an example of preemption in NR. In step S501, terminal 20 performs sensing in the sensing window. If terminal 20 is performing power-saving operation, sensing may be performed for a predetermined limited period. Subsequently, terminal 20 identifies each resource in the resource selection window based on the sensing results and selects a set of resource candidates S A The terminal 20 then determines the set of resource candidates S and selects the resource to be used for transmission (S502). ASelect a resource set (r_0, r_1, ...) from which to determine preemption (S503). This resource set may be notified to the PHY layer from the upper layer as a resource to determine whether or not preemption has occurred.

[0074] In step S504, terminal 20, at timings T(r_0)-T3 shown in Figure 16, re-identifies each resource in the resource selection window based on the sensing results and selects a set of resource candidates S. A The system determines this and then determines preemption for the resource set (r_0, r_1, ...) based on priority. For example, in Figure 16, r_1 is detected by resensing as an SCI transmitted from another terminal 20, and S A It is not included in S. If preemption is enabled, terminal 20 determines that resource r_1 has been preempted if the value prio_RX, which indicates the priority of an SCI sent from another terminal 20, is lower than the value prio_TX, which indicates the priority of a transport block sent from its own terminal. Note that a lower value indicates a higher priority. In other words, if the value prio_RX, which indicates the priority of an SCI sent from another terminal 20, is higher than the value prio_TX, which indicates the priority of a transport block sent from its own terminal, terminal 20 determines that resource r_1 has been preempted. A It is not excluded. Alternatively, if preemption is only effective for a specific priority (for example, if sl-PreemptionEnable is one of pl1, pl2, ..., pl8), this priority is set to prio_pre. In this case, if the value prio_RX, which indicates the priority of the SCI sent from another terminal 20, is lower than prio_pre, and prio_RX is lower than the value prio_TX, which indicates the priority of the transport block sent from the terminal itself, terminal 20 determines that resource r_1 has been preempted.

[0075] In step S505, if preemption is determined in step S504, terminal 20 notifies the upper layer of the preemption, the upper layer re-selects the resource, and the preemption check is terminated.

[0076] If re-evaluation is performed instead of preemption checking, in step S504 above, the set of resource candidates S A After deciding, S A If the resource set (r_0, r_1, ...) does not contain any resources, those resources will not be used, and a re-selection of resources will be performed in the higher layer.

[0077] Figure 17 shows an example of partial sensing operation in LTE. When partial sensing is configured from the upper layer in an LTE sidelink, terminal 20 selects and transmits resources as shown in Figure 17. As shown in Figure 17, terminal 20 performs partial sensing on a portion of the sensing window in the resource pool, i.e., the sensing target. Through partial sensing, terminal 20 receives the resource reservation field included in the SCI transmitted from another terminal 20 and identifies available resource candidates in the resource selection window in the resource pool based on this field. Subsequently, terminal 20 randomly selects a resource from the available resource candidates.

[0078] Figure 17 shows subframe t0 SL From subframe t Tmax-1 SL This is an example of setting the resource pool up to this point. The resource pool may also have its target area defined by, for example, a bitmap. As shown in Figure 17, the transmission trigger at terminal 20 is assumed to occur in subframe n. As shown in Figure 17, of the subframes from subframe n+T1 to subframe n+T2, subframe t y1 SL From subframe t yY SLThe Y subframe up to this point may be set as the resource selection window.

[0079] Terminal 20 has a subframe t whose Y subframe length. y1-k×Pstep SL From subframe t yY-k×Pstep SL Up to one or more sensing targets, it is possible to detect, for example, that another terminal 20 is transmitting. k may be determined by, for example, a 10-bit bitmap. Figure 17 shows an example where the 3rd and 6th bits of the bitmap are set to "1" to indicate that partial sensing is being performed. That is, in Figure 17, subframe t y1-6×Pstep SL From subframe t yY-6×Pstep SL up to and subframe t y1-3×Pstep SL From subframe t yY-3×Pstep SL Up to and are set as sensing targets. As described above, the k-th bit of the bitmap is subframe t y1-k×Pstep SL From subframe t yY-k×Pstep SL It may also support a sensing window up to y. i This corresponds to the index (1...Y) within the Y subframe.

[0080] Note that k is set as a 10-bit bitmap or is predetermined, P step It may be 100ms. However, when performing SL communication with DL and UL carriers, P step This can also be expressed as (U / (D+S+U))*100ms, where U is the number of UL subframes, D is the number of DL subframes, and S is the number of special subframes.

[0081] If an SCI is detected in the sensing target and the RSRP exceeds the threshold, the resources in the resource selection window corresponding to the resource reservation field of that SCI are excluded. Conversely, if an SCI is detected in the sensing target and the RSRP is below the threshold, the resources in the resource selection window corresponding to the resource reservation field of that SCI are not excluded. This threshold is, for example, the sender priority p. TX and receiver priority p RX Based on this, thresholds Th are set or defined for each resource within the sensing target. pTX,pRX That's fine.

[0082] As shown in Figure 17, in the resource selection window set in the Y subframe of the interval [n+T1, n+T2], terminal 20 identifies resources occupied by other UEs, and the resources remaining after excluding those resources become the available resource candidates. Note that the Y subframes do not have to be consecutive. The set of available resource candidates is S A Therefore, S A If the number is less than 20% of the resources in the resource selection window, the threshold Th is set for each resource of the sensing target. pTX,pRX You can increase the level by 3dB and perform resource identification again.

[0083] That is, the threshold Th pTX,pRX You may increase the number of resources that are not excluded because their RSRP is below the threshold by raising the value and performing resource identification again. A Measure the RSSI of each resource and set the resource with the smallest RSSI to group S. B It may also be added to the set of resource candidates S. B Until it fills more than 20% of the resource selection window, S A The RSSI included is the smallest resource S B You may repeat the action of adding to it.

[0084] The lower layer of terminal 20 is S B This may be reported to the upper layer. The upper layer of terminal 20 is SB Terminal 20 may perform a random selection to determine which resource to use. Terminal 20 may use the determined resource to perform a sidelink transmission. After securing a resource once, terminal 20 may perform a predetermined number of operations (for example, C resel (This time) Resources may be used periodically without performing sensing.

[0085] Here, in NR Release 17 sidelinks, power saving based on random resource selection and partial sensing is being considered. For example, for power saving purposes, random resource selection and partial sensing in sidelinks in LTE Release 14 may be applied to resource allocation mode 2 of NR Release 16 sidelinks. Terminal 20 to which partial sensing is applied performs reception and sensing only in specific slots within the sensing window.

[0086] Furthermore, in NR Release 17 Sidelink, eURLLC (enhanced Ultra Reliable Low Latency Communication) is being considered with inter-UE coordination as the baseline. For example, terminal 20A may share information indicating the resource set with terminal 20B, and terminal 20B may take this information into consideration when selecting resources for transmission.

[0087] For example, as a method of resource allocation in a side link, terminal 20 may perform full sensing as shown in Figure 14. Alternatively, terminal 20 may perform partial sensing, which identifies resources by sensing only a limited set of resources compared to full sensing, and selects resources from the identified resource set. Furthermore, terminal 20 may perform random selection, which identifies the resources in the resource selection window as an identified resource set without excluding any resources from the resources in the resource selection window, and selects resources from that identified resource set.

[0088] Furthermore, at the time of resource selection, a method that performs random selection and uses sensing information during re-evaluation or preemption checks may be treated as partial sensing or as random selection.

[0089] Furthermore, the following 1) and 2) may be applied as operations in sensing.

[0090] 1)Periodic-based partial sensing In a system that performs sensing on only a portion of the slots, this operation determines which slots to sense based on the reservation periodicity. The reservation period is a value related to the resource reservation period field.

[0091] 2) Contiguous partial sensing In a system where sensing is performed on only a portion of the slots, the sensing slots are determined based on aperiodic reservations. Note that aperiodic reservations are values ​​related to the time resource assignment field.

[0092] Release 17 may define the operation assuming three types of terminals 20. One is type A, and a type A terminal 20 has no ability to receive any sidelink signals and channels, except for receiving PSFCH and S-SSB.

[0093] The other is type B, and terminal 20 of type B does not have the ability to receive any sidelink signals and channels except PSFCH and S-SSB reception.

[0094] The other is Type D, and a Type D terminal 20 has the ability to receive signals and channels of all sidelinks as defined in Release 16, except that it does not exclude receiving signals and channels of some sidelinks.

[0095] Furthermore, UE types other than the above-mentioned types A, B, and D may be assumed, and UE types and UE capabilities may or may not be associated.

[0096] Furthermore, in Release 17, multiple resource allocation methods can be configured for a given resource pool. Additionally, SL-DRX (Discontinuous reception) is supported as a power-saving feature; that is, reception operations are performed only during predetermined time intervals.

[0097] In resource allocation mode 2, where terminal 20 autonomously selects resources, terminal 20 receives resource reservation information from other terminals 20 via sensing and selects the resources to use for transmission based on that resource reservation information. However, even when each transmitting terminal 20 selects resources based on sensing, resource collisions can still occur. To improve communication reliability and reduce latency, there are communication situations that should be considered, as shown below.

[0098] Figure 18 shows an example of a communication situation (1). As an example of the hidden terminal problem, as shown in Figure 18, when terminal 20B attempts to transmit to terminal 20A, terminal 20C, which cannot be detected by terminal 20A, may be located in a position that interferes with the receiving terminal 20B. For example, if terminal 20C transmits within a time resource reserved by terminal 20A, resource overlap will occur when terminal 20B receives.

[0099] Furthermore, since sidelink is half-duplex communication, resource collisions may occur if both terminals 20 attempt to transmit data.

[0100] Figure 19 shows an example of a communication situation (2). As an example of the near-far problem, as shown in Figure 19, when terminal 20C attempts to transmit to terminal 20A, terminal 20B, which is detected with low power by the transmitting terminal 20C, may be located in a position that causes significant interference to the receiving terminal 20A.

[0101] Figure 20 shows an example of a communication situation (3). As an example of a transmission resource collision in the time domain, as shown in Figure 20, a PSFCH transmission resource reserved from terminal 20B or associated with PSSCH and a PSFCH transmission resource reserved from terminal 20C or associated with PSSCH may overlap at terminal 20A. When multiple transmissions overlap, drops or power reductions occur. For example, it is expected that overlaps between PSFCH and PSFCH, or between PSFCH and UL channels, as shown in Figure 20, may occur.

[0102] Figure 21 is a diagram illustrating example (4) of the communication situation. As an example of a collision between receiving and transmitting resources in the time domain, as shown in Figure 21, there is a case where PSSCH reception on a resource reserved by terminal 20B and PSSCH transmission on a resource reserved by terminal 20A overlap at terminal 20A.

[0103] Figure 22 is a diagram illustrating an example of a communication situation (5). As an example of a collision between transmitting and receiving resources in the time domain, as shown in Figure 22, a PSFCH associated with a PSSCH reserved by terminal 20B and a PSFCH associated with a PSSCH reserved by terminal 20A may overlap at terminal 20A.

[0104] Inter-terminal coordination is being considered as a method to improve reliability and latency performance. For example, inter-terminal coordination method 1 and inter-terminal coordination method 2, shown below, are being considered. Hereinafter, terminal 20 that transmits coordination information will be referred to as UE-A, and terminal 20 that receives coordination information will be referred to as UE-B.

[0105] Inter-terminal coordination method 1) For UE-B to transmit, the preferred resource set and / or non-preferred resource set are sent from UE-A to UE-B.

[0106] Inter-terminal coordination method 2) UE-A transmits to UE-B the fact that a collision with another transmission or reception is expected, possible, or detected in the resource indicated by the SCI received from UE-B. Note that "resource set" may be replaced with this fact.

[0107] Furthermore, for example, regarding inter-terminal cooperation, the methods described in 1)-6) below may be determined.

[0108] 1) When and how does terminal 20A determine the contents of the resource set? UL scheduling may be considered. 2) When does terminal 20A notify terminal 20B of the resource set, and which terminal 20 notifies the resource set? 3) How to determine which terminal 20 notifies which other terminal 20 of the resource set. 4) How does terminal 20A notify about resource sets? What method of notification should be used, explicitly or implicitly? 5) When and how does terminal 20B receive or not receive the resource set? Also, when and how does terminal 20B reflect the received resource set in the resource selection for transmission or not? 6) How to define or not define the relationship between inter-terminal coordination support and signaling and the cast type.

[0109] In the above-described inter-terminal cooperation method 1), UE-B may perform the operations as shown in 1)-4) below.

[0110] 1) The resources of UE-B used for resource selection or resource reselection for transmission may be based on both the sensing results of UE-B and the coordination information received from UE-A. However, this may be limited to cases where the sensing results of UE-B are available, and if the sensing results of UE-B are unavailable, the selection may be based solely on the coordination information received from UE-A. 2) The resources of UE-B used for resource selection or resource reselection for transmission may be based solely on the coordination information received from UE-A. 3) The re-selected resources of UE-B may be determined based on the coordination information received from UE-A. 4) The resources of UE-B used for resource selection or resource reselection for transmission may be based on the coordination information received from UE-A.

[0111] In the above-described inter-terminal cooperation method 2), UE-B may perform the operations as shown in 1)-2) below.

[0112] 1) UE-B may determine which resources to reselect based on the coordination information received from UE-A. 2) UE-B may decide whether retransmission is necessary based on the coordination information received from UE-A.

[0113] Figure 23 is a sequence diagram illustrating an example of UE-to-UE coordination in an embodiment of the present invention. In step S1, UE-A transmits coordination information to UE-B. In the subsequent step S2, UE-B performs a predetermined operation based on the coordination information.

[0114] Here, in the above-mentioned inter-terminal coordination method 2), it is being considered to transmit notifications related to coordination information, similar to PSFCH. For example, if UE-A receives information related to a transmission or reservation by UE-B and detects a collision with some signal based on that information, it may transmit information to UE-B via a channel similar to PSFCH to indicate that a collision has occurred and / or to indicate that resource reselection or retransmission should be performed. Hereinafter, the channel similar to PSFCH on which such information is transmitted will be referred to as PSCICH (Physical Sidelink Collision Indication Channel), but may also be referred to as PSFCH, and is not limited to these terms.

[0115] Figure 24 is a diagram illustrating an example (1) of inter-UE coordination in an embodiment of the present invention. As shown in Figure 24, UE-A may determine the resources of PSCICH based on the resources of the signal received from UE-B. That is, it may be an operation similar to release 16PSFCH. As shown in Figure 24, the minimum gap from the received signal to the PSFCH may be specified by the parameter sl-MinTimeGapPSFCH. Also, as shown in Figure 24, the minimum gap from the received signal to the PSFCH may be specified by the parameter sl-MinTimeGapPSCICH.

[0116] Figure 25 illustrates an example (2) of inter-UE coordination in an embodiment of the present invention. As shown in Figure 25, UE-A may determine the PSCICH resource based on the resource reserved by the signal received from UE-B. That is, it may be a different operation from release 16PSFCH. As shown in Figure 25, the minimum gap from the resource reserved by the received signal to the PSCICH may be specified by the parameter sl-MinTimeGapPSCICH.

[0117] Here, in the above-mentioned inter-terminal coordination method 2), if UE-A determines the PSCICH resource based on the resource reserved by the signal received from UE-B, it is necessary to define the operation when UE-B reserves multiple resources. For example, it is necessary to define which of the multiple reserved resources is used to determine the PSCICH resource. It is also necessary to define the operation of UE-B when receiving PSCICH for multiple reserved resources. Furthermore, it is necessary to define the operation corresponding to aperiodic reservations, i.e., reservations using the time resource allocation field, and periodic reservations, i.e., reservations using the resource reservation period field.

[0118] Figure 26 is a diagram illustrating an example (3) of inter-UE cooperation in an embodiment of the present invention. As shown in Figure 26, UE-B has transmission data to UE-A and reserves a resource for transmission. Subsequently, UE-A receives the resource reservation and anticipates a collision in the reserved resource. Figure 26 shows an example where the reserved resource collides with UE-C's PSSCH transmission resource. Subsequently, UE-A transmits a signal related to the collision prediction to UE-B. Subsequently, after receiving the signal related to the collision prediction, UE-B stops using the reserved resource and performs resource reselection. Subsequently, UE-B transmits transmission data to UE-A using the reselected resource.

[0119] As a condition for collision detection, UE-A may be limited to terminal 20 which is the destination of the transport block of UE-B. UE-A may also be terminal 20 indicated by the UE-ID associated with the signal transmission of UE-B. The UE-ID may be an ID at Layer 1 or an ID at Layer 2. Note that "destination of the transport block" may be replaced with "intended by UE-B".

[0120] Furthermore, for reservation signals for different transport block transmissions sent from UE-B, it may be assumed that the reserved resources are used for transmissions to the same destination UE-A. For example, such reservation signals may be reserved by a resource reservation period field.

[0121] Furthermore, if the signal transmitted from UE-B has multiple destinations, all terminals 20 at those destinations may be UE-A, or some of the terminals 20 at those multiple destinations may be UE-A. For example, if the signal has multiple destinations, the signal transmitted from UE-B may be a broadcast or a groupcast. Among the terminals 20 at those multiple destinations, the terminals 20 located within the communication range requirement may be UE-A.

[0122] Among the multiple destination terminals 20, the terminal 20 whose received RSRP of the signal transmitted from UE-B is above a predetermined value may be designated as UE-A, or the terminal 20 whose received RSRP of the signal transmitted from UE-B is below a predetermined value may be designated as UE-A. If, among the multiple destination terminals 20, the terminal 20 whose received RSRP of the signal transmitted from UE-B is above a predetermined value is designated as UE-A, the system can operate to improve the quality at the terminal 20 to which the data is most desired. If, among the multiple destination terminals 20, the terminal 20 whose received RSRP of the signal transmitted from UE-B is below a predetermined value is designated as UE-A, it becomes easier to share information that UE-B cannot detect.

[0123] When UE-A detects a collision, if UE-B's reservation signal reserves two or more resources using the time resource allocation field, UE-A may send PSCICH to UE-B using one of the methods 1-1), 1-2), 1-3), or 1-4) shown below. UE-B's reservation signal may indicate one transmit resource and two reserved resources.

[0124] Method 1-1) UE-A may send a PSCICH to each of UE-B's reserved resources where a collision has been detected. Figure 27 is a diagram illustrating an example (4) of inter-UE cooperation in an embodiment of the present invention. Figure 27 shows a case where a collision has been detected in both of UE-A's two reserved resources. As shown in Figure 27, a PSCICH may be sent to resources where a collision has been detected between UE-B's reserved resource and UE-C's reserved resource, and furthermore, a PSCICH may be sent to resources where a collision has been detected between UE-B's reserved resource and UE-D's reserved resource. In other words, terminal 20 does not have to send a PSCICH to resources where no collision has been detected.

[0125] Furthermore, for example, among the reserved resources, resources capable of transmitting PSCICH may be limited, and whether or not it is capable of transmitting may mean whether or not processing time for the UE involved in the transmission can be secured and / or whether or not processing time can be secured for the UE-B to perform the corresponding action after reception. The same applies to the following methods.

[0126] Method 1-2) UE-A may send a PSCICH to any of the reserved resources of UE-B in which a collision has been detected. Figure 28 is a diagram illustrating an example (5) of inter-UE cooperation in an embodiment of the present invention. Figure 28 shows a case in which a collision has been detected in both of UE-A's reserved resources. For example, as shown in Figure 28, terminal 20 may send the earliest PSCICH in the time domain among the resources in which a collision has been detected that is capable of sending a PSCICH.

[0127] Figure 29 is a diagram illustrating an example (6) of inter-UE cooperation in an embodiment of the present invention. Figure 29 shows a case in which a collision is detected in only the second of UE-A's reserved resources. As shown in Figure 29, terminal 20 may send a PSCICH to the second resource in which a collision is detected.

[0128] For example, different PSCICH resources may be used based on which reserved resources are in conflict. Also, for example, different information may be sent based on which reserved resources are in conflict.

[0129] Method 1-3) UE-A may send a PSCICH to either of UE-B's reserved resources, regardless of whether a collision is detected or not. Figure 30 is a diagram illustrating an example (7) of inter-UE cooperation in an embodiment of the present invention. Figure 30 shows a case where a collision is detected in only the second of UE-A's reserved resources. For example, as shown in Figure 30, terminal 20 may send the earliest PSCICH in the time domain among the reserved resources to which a PSCICH can be sent. As shown in Figure 30, terminal 20 may send a PSCICH at the timing corresponding to the first reserved resource to which no collision has been detected.

[0130] Method 1-4) UE-A may send a PSCICH to all of UE-B's reserved resources. For example, terminal 20 may send the earliest PSCICH in the time domain among the reserved resources that is capable of sending a PSCICH. That is, terminal 20 may send the corresponding PSCICH even if no collision has been detected in the reserved resources.

[0131] For example, if UE-A receives another reserved signal from UE-B, UE-A does not need to send a PSCICH for the reserved signal it has already received. Also, if UE-A receives another reserved signal from UE-B, and the destination of that other reserved signal is the same as the reserved signal it has already received, UE-A does not need to send a PSCICH for the reserved signal it has already received.

[0132] In methods 1-1), 1-2), 1-3), and 1-4) described above, the PSCICH resource may be a time resource that is a predetermined time prior to the reserved resource, and the time prior may be determined based on a parameter. This parameter may be, for example, sl-MinTimeGapPSCICH. UE-A may transmit the PSCICH in the first of several slots in the resource pool prior to the PSSCH resource reserved by UE-B where a resource collision was detected, which include the PSCICH determined by sl-MinTimeGapPSCICH. The procedure for determining the frequency resource and / or code resource of the PSCICH may be the same as that for the PSFCH.

[0133] As described above, by transmitting coordinating information via PSCICH, the resource to which the corresponding signal should be transmitted when a resource collision is detected can be clearly identified. In Method 1-1), the UE-B can recognize which reserved resource the collision is occurring on, thus avoiding unnecessary resource re-selection. In Methods 1-2) and 1-3), the UE-B can recognize a resource collision as quickly as possible, improving latency performance. In Method 1-4), the reliability of notification of coordinating information regarding resource collision detection can be improved.

[0134] When UE-A detects a collision, if UE-B's reservation signal reserves a resource with period P using the resource reservation period field, UE-A may send PSCICH to UE-B using one of the methods 2-1), 2-2), 2-3), or 2-4) shown below. UE-B's reservation signal may reserve two or more resources.

[0135] Method 2-1) UE-A may send a PSCICH to each of the reserved resources with period P in which a collision is detected. For example, UE-A does not need to send a PSCICH to resources in which no collision has been detected.

[0136] Method 2-2) UE-A may send a PSCICH to any of the reserved resources with period P that have been found to be in collision. For example, UE-A may send a PSCICH to the earliest resource in the time domain that is capable of sending a PSCICH. Alternatively, for example, UE-A may use different PSCICH resources based on which reserved resources are in collision. Alternatively, for example, UE-A may send different information via PSCICH based on which reserved resources are in collision.

[0137] Method 2-3) UE-A may send a PSCICH to any of the reserved resources of period P. For example, UE-A may send a PSCICH to the earliest resource in the time domain that is capable of receiving a PSCICH. Alternatively, for example, UE-A may send a PSCICH to a reserved resource for which no collision has been detected.

[0138] Method 2-4) UE-A may transmit PSCICH for all of the reserved resources of period P. For example, UE-A may transmit PSCICH for reserved resources for which no collision has been detected. Also, for example, if UE-A receives another reserved signal from UE-B, UE-A does not have to transmit PSCICH for the reserved signal already received. Also, for example, if UE-A receives another reserved signal from UE-B and the destination of that other reserved signal is the same as the reserved signal already received, UE-A does not have to transmit PSCICH for the reserved signal already received.

[0139] As described above, by transmitting coordinating information via PSCICH, the resource to which the corresponding signal should be transmitted when a resource collision is detected can be clearly identified. In Method 2-1), the UE-B can recognize which reserved resource the collision is occurring on, thus avoiding unnecessary resource re-selection. In Methods 2-2) and 2-3), the UE-B can recognize a resource collision as quickly as possible, improving latency performance. In Method 2-4), the reliability of notification of coordinating information regarding resource collision detection can be improved.

[0140] In methods 1-1), 1-2), 1-3), 1-4), 2-1), 2-2), 2-3), and 2-4) described above, if UE-B receives a PSCICH from UE-A and the SCI that reserves the reserved resource corresponding to the PSCICH reserves two or more resources, UE-B may perform one of the actions shown in methods 3-1), 3-2), 3-3), and 3-4) below.

[0141] Method 3-1) UE-B does not have to use the reserved resource corresponding to the PSCICH, or it may perform resource reselection for the reserved resource. For example, UE-B does not have to perform resource reselection for reserved resources other than the reserved resource corresponding to the PSCICH.

[0142] Furthermore, for example, the reserved resources to which the operation described in method 3-1) above is applied may be limited to reserved resources to which UE-B can secure processing time to deactivate or reselect the resource after receiving it. The same applies to the following methods.

[0143] Method 3-2) UE-B does not have to use all the reserved resources reserved by the SCI that reserved the reserved resource corresponding to the PSCICH, or it may perform resource reselection for all of those reserved resources.

[0144] Method 3-3) UE-B may choose not to use the reserved resource indicated by PSCICH, or it may perform a resource reselection for that reserved resource.

[0145] Method 3-4) UE-B may choose not to use the reserved resource indicated by PSCICH for subsequent reserved resources in the time domain, or it may perform a resource reselection for the reserved resource.

[0146] By performing the actions described in methods 3-1), 3-2), 3-3), and 3-4) above, UE-B can avoid resource conflicts based on the notification of coordination information from UE-A.

[0147] The above-described embodiment may be applied to an operation in which one terminal 20 sets or allocates transmission resources for another terminal 20.

[0148] The above-described embodiment is not limited to V2X terminals, but may also be applied to terminals that perform D2D communication.

[0149] The operation described in the above embodiment may be performed only in a specific resource pool. For example, it may be performed only in resource pools where terminal 20 of release 17 or later is available.

[0150] In the above embodiment, when terminal 20 receives information related to inter-terminal coordination from another terminal 20, it can select or re-select resources based on that information. Furthermore, when terminal 20 receives information related to inter-terminal coordination from another terminal 20, it can decide whether or not to retransmit the transport block it has sent based on that information.

[0151] In other words, it is possible to improve the reliability of communication during autonomous resource selection in direct communication between terminals.

[0152] (Device configuration) Next, we will describe an example of the functional configuration of the base station 10 and terminal 20 that perform the processes and operations described above. The base station 10 and terminal 20 include functions to implement the embodiments described above. However, the base station 10 and terminal 20 may each have only some of the functions in the embodiments.

[0153] <Base station 10> Figure 31 is a diagram showing an example of the functional configuration of the base station 10. As shown in Figure 31, 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 Figure 31 is merely an example. The names of the functional categories and functional units can be anything as long as they can perform the operations according to the embodiment of the present invention.

[0154] The transmitting unit 110 includes the function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiving unit 120 includes the function of receiving various signals transmitted from the terminal 20 and obtaining information from the received signals, for example, information from a higher layer. The transmitting unit 110 also has the function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL reference signals, etc. to the terminal 20.

[0155] The setting unit 130 stores pre-configured setting information and various setting information to be transmitted to the terminal 20 in a storage device, and reads it from the storage device as needed. The contents of the setting information include, for example, information related to D2D communication settings.

[0156] As described in the embodiment, the control unit 140 performs processing related to the settings for the terminal 20 to perform D2D communication. The control unit 140 also transmits the scheduling of D2D communication and DL communication to the terminal 20 via the transmission unit 110. The control unit 140 also receives information related to the HARQ response of D2D communication and DL communication from the terminal 20 via the reception unit 120. The signal transmission function unit of the control unit 140 may be included in the transmission unit 110, and the signal reception function unit of the control unit 140 may be included in the reception unit 120.

[0157] <Terminal 20> Figure 32 is a diagram showing an example of the functional configuration of terminal 20. As shown in Figure 32, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Figure 32 is merely an example. The names of the functional categories and functional units can be anything as long as they can perform the operations according to the embodiment of the present invention.

[0158] The transmitting unit 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiving unit 220 wirelessly receives various signals and acquires signals from higher layers from the received physical layer signals. The receiving unit 220 also has the function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals or reference signals transmitted from the base station 10. For example, the transmitting unit 210 transmits PSCCH (Physical Sidelink Control Channel), PSSCH (Physical Sidelink Shared Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel), etc. to other terminals 20 as D2D communication, and the receiving unit 220 receives PSCCH, PSSCH, PSDCH or PSBCH, etc. from other terminals 20.

[0159] The setting unit 230 stores various setting information received from the base station 10 or terminal 20 by the receiving unit 220 in its storage device and reads it from the storage device as needed. The setting unit 230 also stores pre-configured setting information. The content of the setting information is, for example, information related to D2D communication settings.

[0160] As described in the embodiment, the control unit 240 controls D2D communication to establish an RRC connection with other terminals 20. The control unit 240 also performs power-saving operations. The control unit 240 also performs HARQ processing for D2D and DL communication. The control unit 240 transmits information related to the HARQ response for D2D and DL communication scheduled from the base station 10 to the base station 10. The control unit 240 may also schedule D2D communication with other terminals 20. The control unit 240 may also autonomously select resources to be used for D2D communication from a resource selection window based on sensing results, or it may perform re-evaluation or preemption. The control unit 240 also performs power-saving processing for D2D communication transmission and reception. The control unit 240 also performs processing related to inter-terminal coordination in D2D communication. The signal transmission function unit of the control unit 240 may be included in the transmission unit 210, and the signal reception function unit of the control unit 240 may be included in the reception unit 220.

[0161] (Hardware configuration) The block diagrams (Figures 31 and 32) used in the description of the above embodiments show functional units. 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 coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may be realized by combining the one or more devices with software.

[0162] Functions include, but are not limited to, judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. As mentioned above, the method of implementation is not particularly limited.

[0163] For example, the base station 10, terminal 20, etc. in one embodiment of the present disclosure may function as a computer that processes the wireless communication method of the present disclosure. Figure 33 is a diagram showing an example of the hardware configuration of the base station 10 and terminal 20 according to one embodiment of the present disclosure. The above-mentioned base station 10 and 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.

[0164] In the following explanation, the term "device" can be read as "circuit," "device," "unit," etc. The hardware configuration of the base station 10 and terminal 20 may include one or more of the devices shown in the figure, or it may be configured without some of the devices.

[0165] Each function in the base station 10 and terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and storage device 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of the reading and writing of data in the storage device 1002 and auxiliary storage device 1003.

[0166] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control devices, arithmetic units, registers, etc. For example, the control unit 140, control unit 240, etc., described above may be implemented by the processor 1001.

[0167] Furthermore, the processor 1001 reads programs (program code), software modules, or data from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes accordingly. The program used is one that causes a computer to execute at least a part of the operations described in the above embodiment. For example, the control unit 140 of the base station 10 shown in Figure 31 may be implemented 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 Figure 32 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may be transmitted from the network via a telecommunications line.

[0168] The storage device 1002 is a computer-readable recording medium and may consist of at least one of the following: ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. The storage device 1002 may also be called a register, cache, main memory, etc. The storage device 1002 can store executable programs (program code), software modules, etc., for implementing a communication method according to one embodiment of this disclosure.

[0169] The auxiliary storage device 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disc, a digital multipurpose disc, a Blu-ray® disc), a smart card, flash memory (e.g., a card, a stick, a key drive), a floppy® disk, a magnetic strip, etc. The above-mentioned storage medium may also be a database, server, or other suitable medium that includes at least one of the storage device 1002 and the auxiliary storage device 1003.

[0170] The communication device 1004 is hardware (transceiver / receiver device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may include high-frequency switches, duplexers, filters, frequency synthesizers, etc., to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the transmit / receive antenna, amplifier section, transmit / receive section, transmission path interface, etc., may be implemented by the communication device 1004. The transmit / receive section may be implemented with physically or logically separated transmitting and receiving sections.

[0171] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0172] Furthermore, 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 different buses may be configured for each device.

[0173] Furthermore, the base station 10 and terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and some or all of each functional block may be realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0174] (Summary of the embodiments) As described above, according to an embodiment of the present invention, a resource pool includes a receiving unit that receives signals from a first terminal and a second terminal, a control unit that detects that a first reserved resource based on a signal received from the first terminal and a second reserved resource based on a signal received from the second terminal overlap, and a transmitting unit that, when the control unit detects an overlap, transmits information relating to resource selection to the first terminal via a collision notification channel. The control unit is provided with a terminal that determines, if the first reserved resource is a plurality of resources, which of the plurality of resources the collision notification channel to which transmits the information relating to resource selection.

[0175] With the above configuration, terminal 20 can select or re-select resources based on information received from other terminals 20 regarding inter-terminal coordination. Furthermore, terminal 20 can decide whether or not to retransmit the transport block it has sent based on information received from other terminals 20 regarding inter-terminal coordination. In other words, the reliability of communication during autonomous resource selection in direct inter-terminal communication can be improved.

[0176] The control unit may decide to transmit information related to resource selection on a channel that notifies the collision, which is associated with each of the resources that have detected overlap among the plurality of resources. With this configuration, when terminal 20 receives information related to inter-terminal coordination from another terminal 20, it can select or re-select a resource based on that information. Also, when terminal 20 receives information related to inter-terminal coordination from another terminal 20, it can decide whether or not to retransmit the transport block it has sent based on that information.

[0177] The control unit may decide to transmit information relating to resource selection on a channel that notifies of the collision associated with one of the resources that has detected an overlap among the plurality of resources. With this configuration, terminal 20 can select or re-select a resource based on information relating to inter-terminal coordination when it receives such information from another terminal 20. Also, when terminal 20 receives information relating to inter-terminal coordination from another terminal 20, it can decide whether or not to retransmit the transport block it has sent based on such information.

[0178] The control unit may decide to transmit information related to resource selection on the channel that notifies the collision associated with the resource that has the earliest time domain among the resources that have detected overlap among the multiple resources. With this configuration, terminal 20 can select or re-select a resource based on information received from another terminal 20 regarding inter-terminal coordination. Also, when terminal 20 receives information regarding inter-terminal coordination from another terminal 20, it can decide whether or not to retransmit the transport block it has sent based on that information.

[0179] The control unit may decide to transmit information relating to resource selection on the channel that notifies of the collision associated with the earliest resource in the time domain among the multiple resources. With this configuration, terminal 20 can select or re-select a resource based on information relating to inter-terminal coordination when it receives such information from another terminal 20. Also, when terminal 20 receives information relating to inter-terminal coordination from another terminal 20, it can decide whether or not to retransmit the transport block it has sent based on such information.

[0180] Furthermore, according to an embodiment of the present invention, a communication method is provided in which a terminal performs the following steps: a receiving step of receiving signals from a first terminal and a second terminal in a resource pool; a control step of detecting that a first reserved resource based on a signal received from the first terminal and a second reserved resource based on a signal received from the second terminal overlap; a transmission step of transmitting information relating to resource selection to the first terminal via a collision notification channel when an overlap is detected by the control step; and, if the first reserved resource is a plurality of resources, a step of determining which of the plurality of resources the collision notification channel to which transmits the information relating to resource selection.

[0181] With the above configuration, terminal 20 can select or re-select resources based on information received from other terminals 20 regarding inter-terminal coordination. Furthermore, terminal 20 can decide whether or not to retransmit the transport block it has sent based on information received from other terminals 20 regarding inter-terminal coordination. In other words, the reliability of communication during autonomous resource selection in direct inter-terminal communication can be improved.

[0182] (Supplement to the embodiment) While embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, substitutions, etc. Specific numerical examples have been used to facilitate understanding of the invention, but unless otherwise specified, these 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 combined as needed, and matters described in one item may be applied to matters described in another item (as long as they do not contradict each other). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operation of multiple functional units may be physically performed by one part, or the operation of one functional unit may be physically performed by multiple parts. Regarding the processing procedures described in the embodiments, the order of processing may be changed as long as it does not contradict each other. For the convenience of explaining the processing, the base station 10 and terminal 20 have been described using functional block diagrams, but such devices may be implemented in hardware, software, or a combination thereof. The software operated by the processor of the base station 10 according to an embodiment of the present invention and the software operated by the processor of the terminal 20 according to an embodiment of the present invention may be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0183] Furthermore, the notification of information is not limited to the embodiments / models described herein and may be carried out by other methods. For example, the notification of information may be carried out by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof. Also, RRC signaling may be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0184] Each aspect / embodiment described in this disclosure may be applied to at least one of the following systems: 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 appropriate systems, as well as next-generation systems extended based thereon. Furthermore, multiple systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A with 5G).

[0185] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described herein may be reordered, provided they are consistent with each other. For example, the methods described herein present various step elements in an exemplary order and are not limited to that specific order.

[0186] In this specification, specific operations performed by the base station 10 may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station 10, it is clear that various operations performed for communication with the terminal 20 can be performed by the base station 10 and at least one of the other network nodes (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station 10, the other network node may be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0187] The information or signals described in this disclosure may be output from a higher layer (or lower layer) to a lower layer (or higher layer). They may also be input and output via multiple network nodes.

[0188] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be transmitted to other devices.

[0189] The determination in this disclosure may be made by a value represented by one bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value).

[0190] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0191] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0192] The information, signals, etc. described in this disclosure may be represented using any of the various different techniques. 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 voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0193] In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0194] The terms “system” and “network” as used in this disclosure are interchangeable.

[0195] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0196] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0197] In this disclosure, terms such as "base station (BS)", "wireless base station", "base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0198] A base station can house one or more (e.g., three) cells. If a base station houses multiple cells, the entire coverage area of ​​the base station can be divided into several smaller areas, each of which may also be provided with communication services by a base station subsystem (e.g., a Remote Radio Head (RRH)). The terms “cell” or “sector” refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems that provide communication services in that coverage.

[0199] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0200] 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 several other appropriate terms.

[0201] 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 mobile body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile 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 be 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.

[0202] Furthermore, the term "base station" in this disclosure may be interpreted as "user terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple terminals 20 (which may be called, for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything)). In this case, the terminals 20 may have the functions that the base station 10 has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc., may be interpreted as side channel.

[0203] Similarly, the term "user terminal" in this disclosure may be replaced with "base station." In this case, the base station may be configured to have the same functions as the user terminal described above.

[0204] As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiry (e.g., searching in a table, database, or other data structure), and ascertaining. “Determining” may also include, for example, receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, and accessing (e.g., accessing data in memory). Furthermore, "judgment" and "decision" can include considering something as having been "judged" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" and "decision" can include considering something as having been "judged" or "decided" after some action. Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0205] The terms “connected,” “coupled,” or any variation thereof, mean 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” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0206] The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

[0207] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0208] Any reference to elements using the designations “first,” “second,” etc., as 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 way to distinguish between two or more elements. Accordingly, references to the first and second elements do not imply that only two elements may be employed, or that the first element must precede the second element in any way.

[0209] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0210] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0211] A wireless frame may consist of one or more frames in the time domain. Each of these frames in the time domain may be called a subframe. A subframe may further consist 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.

[0212] Numerical logic may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerical logic may include, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain.

[0213] A slot may consist of one or more symbols in the time domain (such as OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.). A slot may also be a time unit based on neurology.

[0214] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. Minislots may also be called subslots. Minislots may consist 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.

[0215] Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Different names may be used for each of these terms.

[0216] 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 mini-slot may be called a TTI. In other words, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, mini-slot, etc., instead of a subframe.

[0217] Here, TTI refers to, for example, the smallest unit of time for scheduling in wireless communication. For example, in an LTE system, the base station schedules each terminal 20 to allocate wireless resources (such as the frequency bandwidth and transmission power available to each terminal 20) in TTI units. However, the definition of TTI is not limited to this.

[0218] TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. Given a TTI, the actual time interval (e.g., number of symbols) to which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI.

[0219] Furthermore, if one slot or one mini-slot is referred to as TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit of scheduling. In addition, the number of slots (number of mini-slots) that constitute the minimum time unit of scheduling may be controlled.

[0220] A TTI with a time length of 1ms may also be called a normal TTI, long TTI, normal subframe, long subframe, slot, etc. A TTI shorter than a normal TTI may also be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, mini slot, sub slot, slot, etc.

[0221] Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more.

[0222] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology.

[0223] Furthermore, the time domain of RB may contain one or more symbols and may be the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks.

[0224] One or more RBs may also be called a Physical RB (PRB), Sub-Carrier Group (SCG), Resource Element Group (REG), PRB pair, RB pair, etc.

[0225] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area comprising one subcarrier and one symbol.

[0226] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a particular neurology system in a given carrier. These common RBs may be identified by an index of the RBs relative to a common reference point of the carrier. A Bandwidth Part (PRB) may be defined and numbered within a given BWP.

[0227] A BWP may include a BWP for UL (Ultraviolet Link) and a BWP for DL ​​(Download Link). One or more BWPs may be set for a terminal 20 within a single carrier.

[0228] At least one of the configured BWPs may be active, and terminal 20 does not need to be expected to send or receive a predetermined signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0229] The structures described above, such as wireless frames, subframes, slots, minislots, and symbols, are merely illustrative. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless 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, and the number of symbols, symbol length, and cyclic prefix (CP) length within a TTI can be varied in various ways.

[0230] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0231] In this 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 "combine" may be interpreted similarly to "different."

[0232] Each aspect / embodiment described herein may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0233] In this disclosure, inter-terminal coordination information is an example of information related to resource selection. PSCICH is an example of a channel for notifying collisions.

[0234] As described above in detail, 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 changed 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 for the purpose of illustration and has no restrictive meaning for the present disclosure.

[0235] This international patent application claims priority based on Japanese Patent Application No. 2021-087198 filed on May 24, 2021, and incorporates the entire contents of Japanese Patent Application No. 2021-087198 into this application.

Explanation of Reference Numerals

[0236] 10 Base station 110 Transmitter 120 Receiver 130 Setting unit 140 Control unit 20 Terminal 210 Transmitter 220 Receiver 230 Setting unit 240 Control unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims

1. A receiving unit that receives first control information from a second terminal, including information about reserved resources for data channels in direct terminal-to-terminal communication, and second control information from a third terminal, including information about reserved resources for data channels in direct terminal-to-terminal communication. A control unit that detects a collision of the reserved resource based on the first control information and the second control information, The system includes a transmission unit that transmits a feedback channel containing collision information of the reserved resource to the second terminal based on a first timing or a second timing, The first timing is based on a first time from the time the first control information is received until the feedback channel is transmitted. The terminal is characterized in that the second timing is based on the processing time required for the second terminal to perform a corresponding action after receiving the feedback channel.

2. The terminal according to claim 1, wherein the first timing is the earliest timing in the time domain at which the feedback channel can transmit after the first time interval.

3. The terminal according to claim 1, wherein the second terminal performs a reselection without using the reserved resource corresponding to the feedback channel.

4. The steps include receiving first control information from a second terminal, which includes information about reserved resources for a data channel in direct terminal-to-terminal communication, and receiving second control information from a third terminal, which includes information about reserved resources for a data channel in direct terminal-to-terminal communication. A step of detecting a collision of the reserved resource based on the first control information and the second control information, The procedure includes the step of transmitting a feedback channel containing collision information of the reserved resource to the second terminal based on a first timing or a second timing, The first timing is based on a first time from the time the first control information is received until the feedback channel is transmitted. A communication method performed by a terminal, wherein the second timing is based on the processing time required for the second terminal to perform a corresponding action after receiving the feedback channel.

5. A communication system including a first terminal, a second terminal, and a third terminal, The first terminal is, A receiving unit that receives first control information from a second terminal, including information about reserved resources for data channels in direct terminal-to-terminal communication, and second control information from a third terminal, including information about reserved resources for data channels in direct terminal-to-terminal communication. A control unit that detects a collision of the reserved resource based on the first control information and the second control information, The system includes a transmission unit that transmits a feedback channel containing collision information of the reserved resource to the second terminal based on a first timing or a second timing, The second terminal is, A transmitting unit that transmits the first control information to the first terminal, The system includes a receiving unit that receives the feedback channel from the first terminal based on the first timing or the second timing, The first timing is based on a first time from the time the first control information is received until the feedback channel is transmitted. A communication system in which the second timing is based on the processing time required for the second terminal to perform a corresponding action after receiving the feedback channel.

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