Terminals, communication methods, and wireless communication systems

Abstract

To improve communication quality on the basis of information notified from other terminals in direct communication between terminals.SOLUTION: A terminal includes a receiving unit that receives control information from a first terminal via a control channel, and a transmitting unit that transmits, to a second terminal, information for avoiding collision between a first resource indicated by the control information, the first resource being used by the first terminal to transmit a shared channel, and a second resource being used by the second terminal to transmit a shared channel, and the transmitting unit transmits, to the second terminal, the information for avoiding the collision at a transmission opportunity for a feedback channel corresponding to a reception slot of the control information via the control channel.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] The present invention relates to a terminal, a communication method, and 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 directly communicate 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 (3rd 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 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

[0006] In direct terminal-to-terminal communication, it is assumed that one terminal can improve communication quality by receiving information from another terminal, such as information related to the resources it will use, and then performing resource selection or other actions based on that information. However, the details of the information that should be shared between terminals and the methods for improving communication quality using that information were unclear.

[0007] This invention has been made in view of the above points, and aims to improve communication quality in direct communication between terminals based on information notified from other terminals. [Means for solving the problem]

[0008] According to the disclosed technology, a terminal is provided comprising: a receiving unit that receives control information from a first terminal via a control channel; and a transmitting unit that transmits to a second terminal information to avoid a collision between a first resource indicated by the control information, which the first terminal uses for transmission on a shared channel, and a second resource used for transmission on a shared channel, wherein the transmitting unit transmits the collision avoidance information to the second terminal in a transmission opportunity for a feedback channel corresponding to the receiving slot of the control information via the control channel. [Effects of the Invention]

[0009] According to the disclosed technology, in direct communication between terminals, communication quality can be improved based on information notified from other terminals. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram for explaining V2X. [Figure 2] This is a diagram for explaining an example (1) of the transmission mode of V2X. [Figure 3] This is a diagram for explaining an example (2) of the transmission mode of V2X. [Figure 4] This is a diagram for explaining an example (3) of the transmission mode of V2X. [Figure 5] This is a diagram for explaining an example (4) of the transmission mode of V2X. [Figure 6] This is a diagram for explaining an example (5) of the transmission mode of V2X. [Figure 7] This is a diagram for explaining an example (1) of the communication type of V2X. [Figure 8] This is a diagram for explaining an example (2) of the communication type of V2X. [Figure 9] This is a diagram for explaining an example (3) of the communication type of V2X. [Figure 10] This is a sequence diagram showing an example (1) of the operation of V2X. [Figure 11] This is a sequence diagram showing an example (2) of the operation of V2X. [Figure 12] This is a sequence diagram showing an example (3) of the operation of V2X. [Figure 13] This is a sequence diagram showing an example (4) of the operation of V2X. [Figure 14] This is a diagram showing an example (1) of information related to the synchronization source in an embodiment of the present invention. [Figure 15] This is a diagram showing an example (2) of information related to the synchronization source in an embodiment of the present invention. [Figure 16] This is a diagram showing an example (1) of information related to the HARQ response in an embodiment of the present invention. [Figure 17] This is a diagram showing an example (2) of information related to the HARQ response in an embodiment of the present invention. [Figure 18] This is a diagram showing an example (1) of information related to transmission power reduction in an embodiment of the present invention. [Figure 19] FIG. 1 is a diagram showing an example (1) of information related to transmission power reduction in an embodiment of the present invention. [Figure 20] FIG. 4 is a diagram showing an example of information related to unused resources in an embodiment of the present invention. [Figure 21] FIG. 7 is a diagram showing an example of the functional configuration of base station 10 in an embodiment of the present invention. [Figure 22] FIG. 10 is a diagram showing an example of the functional configuration of terminal 20 in an embodiment of the present invention. [Figure 23] FIG. 13 is a diagram showing an example of the hardware configuration of base station 10 or terminal 20 in an embodiment of the present invention. Embodiments of the Invention

[0011] Hereinafter, embodiments of the present invention will be described 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 the following embodiments.

[0012] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are appropriately used. However, the existing technology is, for example, existing LTE, but is not limited to existing LTE. In addition, the term "LTE" used in this specification has a broad meaning including LTE-Advanced, and systems after LTE-Advanced (e.g., NR), or wireless LAN (Local Area Network) unless otherwise specified.

[0013] In addition, in the embodiment of the present invention, the duplex method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or another method (e.g., Flexible Duplex, etc.).

[0014] Furthermore, in the embodiments of the present invention, "configuring" wireless parameters means that predetermined values ​​are pre-configured, that wireless parameters notified from the base station 10 or terminal 20 are configured, or that they are predetermined by specifications.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Figure 4 is a diagram illustrating an example (3) of the V2X transmission mode. 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. In NR, the mode in which terminal 20 selects resources and performs sidelink transmission may also be called resource allocation mode 2.

[0027] 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, base station 10 transmits a sidelink grant to terminal 20A via the RRC (Radio Resource Control) setting. Subsequently, terminal 20A transmits PSSCH to terminal 20B based on the received resource pattern (step 1). The sidelink communication transmission mode shown in Figure 5 may also be called sidelink transmission mode 2c in NR.

[0028] 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 information regarding 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 sidelink transmission mode 2d in NR. In NR, the mode in which base station 10 allocates resources to terminal 20 to perform sidelink transmission may be called resource allocation mode 1.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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).

[0033] 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.

[0034] 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".

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] In step S101, 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] If HARQ control is not performed, steps S104 and S105 do not need to be performed.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] If blind retransmission is not performed, step S204 does not need to be executed.

[0053] 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 is applied, the base station 10 may transmit information indicating PSFCH resources to the terminal 20.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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 an ARQ-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 is not included. In NR Rel.16, the codebook of the HARQ-ACK does not include a HARQ-ACK for DL ​​data.

[0061] If HARQ control is not performed, steps S304 and S305 do not need to be executed.

[0062] 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 sequence differences. 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.

[0063] 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 beginning. A PSFCH may be placed in the last symbol of a slot, or in multiple symbols at the end of a slot. In the example shown in Figure 13, three subchannels are configured in the resource pool, and two PSFCHs are placed three slots after the slot in which the PSSCH is placed. The arrows from PSSCH to PSFCH show an example of a PSFCH associated with a PSSCH.

[0064] If the HARQ response in the NR-V2X group cast is option 2, which sends 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 subsequent 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.

[0065] Here, in future releases (e.g., NR Release 17), enhancements to sidelinks (SL enhancement) are being considered. For example, power reduction is being considered based on random resource selection and partial sensing in LTE Release 14. Also, for example, enhanced URLLC (enhanced Ultra-Reliable and Low Latency Communications) is being considered based on inter-UE coordination in the study phase of NR sidelinks. As an example of inter-UE coordination, terminal 20A may share a resource set with terminal 20B, and terminal 20B may take that resource set into consideration when selecting resources.

[0066] It is believed that communication quality can be improved by sending various information from terminal 20A to terminal 20B, and terminal 20B operating based on that information. In other words, it is considered effective to share not only resource sets but also other information between terminals 20. However, it was unclear what kind of information should be shared between terminals 20. Furthermore, it was unclear how the information shared between terminals 20 should be used.

[0067] Therefore, terminal 20A may transmit at least one of the following pieces of information A)-D) to terminal 20B.

[0068] A) Information about the synchronization source B) Information regarding planned PSFCH opportunities for transmission and reception. C) Information regarding reduction in transmit power due to in-device coexistence. D) Information about resources that have been reserved but are not intended to be used.

[0069] Here, terminal 20B may be a single terminal 20 or multiple terminals 20. That is, terminal 20A may groupcast the above information, or terminal 20A may broadcast the above information. The "intradevice coexistence" in C) above may correspond to the case where multiple channels overlap at least in the time domain on terminal 20A.

[0070] Furthermore, terminal 20A may perform resource selection for terminal 20B based on at least one of A)-D) above.

[0071] By performing resource selection using the additional information shown in A)-D) above, higher reliability or communication quality can be ensured.

[0072] Figure 14 shows an example (1) of information relating to the synchronization source in an embodiment of the present invention. The information relating to the synchronization source A) above may be information based on the S-SSB (Sidelink-SS / PBCH block) received by terminal 20. S-SSB is a signal that includes the synchronization signal and broadcast information in the sidelink transmitted by terminal 20. Note that S-SSB_TX indicates the transmitted S-SSB signal.

[0073] As shown in Figure 14, terminal 20A receives S-SSB_TX(i) from terminal 20C. Meanwhile, terminal 20A uses S-SSB_TX received from terminal 20B as its synchronization source. Here, terminal 20A may transmit information related to S-SSB_TX(i) received from terminal 20C, which is a synchronization source other than the one being used, to terminal 20B. For example, the information related to S-SSB_TX(i) may be the RSRP (Reference Signal Received Power) value. Alternatively, for example, the information related to S-SSB_TX(i) may be the time difference (e.g., Xms) between the S-SSB_TX from terminal 20B, which is the synchronization source being used, and the S-SSB_TX(i) from terminal 20C, which is the synchronization source not being used.

[0074] Furthermore, terminal 20A may send the RSRP value of S-SSB_TX received from terminal 20B, which is being used as the synchronization source, to terminal 20B.

[0075] Figure 14 shows an example of synchronization source priority. Base station 10, which is the highest priority gNB / eNB, corresponds to priority P0. Terminal 20D, which is the next highest priority gNB / eNB and is directly synchronized with it, corresponds to priority P1. Terminal 20B, which is the next highest priority gNB / eNB and is indirectly synchronized with it, corresponds to priority P2. GNSS 30, which is the next highest priority, corresponds to priority P3. Terminal 20E, which is the next highest priority GNSS and is directly synchronized with it, corresponds to priority P4. Terminal 20F, which is the next highest priority GNSS and is indirectly synchronized with it, corresponds to priority P5. Terminals 20A, 20C, and 20G, which are the lowest priority UEs, correspond to priority P6.

[0076] Figure 15 shows an example (2) of information relating to the synchronization source in an embodiment of the present invention. Terminal 20B shown in Figure 14 may perform resource allocation operations based on S-SSB information transmitted from terminal 20C that it has received from terminal 20A.

[0077] For example, terminal 20B may decode the SCI in PSCCH / PSSCH and perform sensing based on the S-SSB information transmitted from terminal 20C that it received from terminal 20A.

[0078] Furthermore, as shown in Figure 15, for example, the time difference of the synchronization source may be determined based on the S-SSB information transmitted from terminal 20C received from terminal 20A. This time difference may correspond to the time difference between a resource pool based on synchronization source information received from other UEs and a resource pool based on the synchronization source currently in use. Terminal 20B may detect power based on the above-mentioned time difference of the synchronization source. For example, if sensing based on the above-mentioned time difference of the synchronization source detects that the change in power exceeds a predetermined value, terminal 20B may determine that some kind of transmission has occurred, regardless of whether the SCI decoding was successful or not.

[0079] Terminal 20B may identify resources based on the time difference of the synchronization source described above, determine which resources are unavailable, and exclude them from the group of candidate resources assumed to be available. For example, terminal 20B may exclude resources determined from the Time resource assignment field and / or Resource reservation period field of the decoded SCI from the group of candidate resources assumed to be available. Alternatively, for example, if sensing based on the time difference of the synchronization source described above determines that a transmission exists, terminal 20B may exclude resources determined from the Time resource assignment field and / or Resource reservation period field that can be indicated by that transmission from the group of candidate resources assumed to be available.

[0080] Furthermore, for example, terminal 20B may decide whether or not to abort the transmission based on the time difference and / or power detection of the synchronization source described above. For example, if terminal 20B detects a transmission based on a different synchronization source, it may abort the sidelink transmission on the associated resource.

[0081] As described above, by selecting or allocating resources based on information about synchronization sources obtained from other terminals 20, resources can be selected so as not to conflict with transmissions from terminals 20 that operate based on other synchronization sources.

[0082] Figure 16 shows an example (1) of information relating to the HARQ response in an embodiment of the present invention. The information B) regarding PSFCH opportunities to be transmitted and received above may be information relating to the transmission and reception of PSFCH related to communication with any terminal. Information relating to PSFCH opportunities may be, for example, information indicating the time domain and / or frequency domain and / or code domain in which the PSFCH opportunity is set. For example, it may be information relating to PSFCH opportunities as shown in 1)-4) below.

[0083] 1) PSFCH opportunity corresponding to PSCCH / PSSCH received by terminal 20 2) PSFCH opportunity corresponding to the resource indicated by the time resource allocation field included in the SCI in the PSCCH / PSSCH received by terminal 20 3) PSFCH opportunity corresponding to the resource indicated by the resource reservation period field included in the SCI in the PSCCH / PSSCH received by terminal 20 4) PSFCH opportunity corresponding to the resource selected for transmission at terminal 20 (i.e., an unreserved resource)

[0084] Figure 16 shows an example corresponding to item 2) above, in which terminal 20B notifies terminal 20C of information regarding a PSFCH opportunity corresponding to a PSCCH / PSSCH received from terminal 20A. The duration of the first few symbols of the PSCCH / PSSCH shown in Figure 16 represents an example of the time required for switching sidelink transmission and reception. As shown in Figure 16, terminal 20A transmits a PSCCH / PSSCH to terminal 20B. Information regarding a PSFCH opportunity corresponding to two resources indicated by the time resource allocation field notified to terminal 20B by the PSCCH / PSSCH may be notified from terminal 20B to terminal 20C.

[0085] Priority information may also be notified together with or independently of the PSFCH opportunity information. This priority may be a priority in the SCI, or a priority in a higher layer (for example, the priority of the logical channel associated with the corresponding PSCCH / PSSCH). Note that for the PSFCH opportunities shown in 1)-4) above, "received" may be replaced with "transmitted". For example, information about a PSFCH opportunity corresponding to a PSCCH / PSSCH transmitted by terminal 20 may be notified to other terminals 20. Note that terminals 20 shown in 1)-4) above may be replaced with any terminal 20. For example, terminal 20A shown in Figure 16 may transmit information about a PSFCH opportunity to be sent to terminal 20C.

[0086] As described above, by notifying other terminals 20 of the PSFCH information that terminal 20 receives or transmits, it is possible to predict collisions between PSFCH transmissions and receptions and PSFCH transmissions and receptions by the terminal itself, and to avoid collisions as necessary.

[0087] Figure 17 shows an example (2) of information relating to the HARQ response in an embodiment of the present invention. Terminal 20 may perform resource allocation operations based on information about PSFCH opportunities received from other terminals. In Figure 17, as shown in Figure 16, terminal 20C is assumed to have received from terminal 20B information about PSFCH opportunities corresponding to PSCCH / PSSCH transmitted from terminal 20A to terminal 20B.

[0088] As shown in Figure 17, terminal 20C may perform at least one of the actions described in 1)-3) below based on the information regarding PSFCH opportunities received from terminal 20B.

[0089] 1) Terminal 20C may determine the PSCCH / PSSCH resources corresponding to the PSFCH opportunity used by Terminal 20B and exclude them from the available candidate resources (i.e., the resource selection window). This exclusion may only be applied if Terminal 20C intends to retransmit based on a HARQ response. It may also be applied if the priority of the PSFCH that Terminal 20B transmits or receives in the PSFCH opportunity used by Terminal 20B takes precedence over a specific value. The specific value may be, for example, the priority corresponding to the PSCCH / PSSCH that Terminal 20C intends to transmit to Terminal 20B. This exclusion may only be applied if Terminal 20C transmits to one or more Terminals 20, including Terminal 20B. The PSFCH opportunity used by Terminal 20B may be a PSFCH opportunity in which Terminal 20B can transmit a PSFCH, or a PSFCH opportunity in which Terminal 20B can receive a PSFCH.

[0090] 2) If terminal 20B is in a PSFCH opportunity where it can perform a PSFCH transmission, terminal 20C may determine the PSCCH / PSSCH resource corresponding to the PSFCH opportunity used by terminal 20B and exclude it from the available candidate resource group (i.e., resource selection window) only if the number of PSFCH transmissions in that PSFCH opportunity is greater than a predetermined number or equal to a predetermined number.

[0091] 3) If terminal 20B is capable of receiving PSFCH, terminal 20C may determine the PSCCH / PSSCH resource corresponding to the PSFCH opportunity used by terminal 20B and exclude it from the available candidate resource group (i.e., resource selection window) only if the number of PSFCH receptions in that PSFCH opportunity is greater than a predetermined number or equal to a predetermined number.

[0092] As described above, by notifying other terminals 20 of the PSFCH information that terminal 20 receives or transmits, it becomes possible to select resources other than those from which PSFCH transmission from the receiving terminal is not expected, thereby guaranteeing HARQ feedback.

[0093] Figure 18 shows an example (1) of information relating to transmission power reduction in an embodiment of the present invention. The information regarding transmission power reduction due to in-device coexistence described above (C) may be information regarding transmission power reduction due to the overlap of SL transmission and UL transmission in at least the time domain in either terminal 20. Alternatively, SL transmission and UL transmission may be replaced with a first SL transmission and a second SL transmission, where the first SL transmission is an SL transmission in NR and the second SL transmission is an SL transmission in LTE. Hereinafter, SL transmission and UL transmission will be described as examples. For example, the information regarding transmission power reduction may be the fact that UL transmission takes precedence over SL transmission and reduces the transmission power of SL transmission. Alternatively, for example, the information regarding transmission power reduction may be the amount of transmission power reduction when UL transmission takes precedence over SL transmission and reduces the transmission power of SL transmission. A specific granularity may be applied to the amount of transmission power reduction.

[0094] As shown in Figure 18, if the transmission power of an SL transmission is reduced by an UL transmission, i.e., a PUSCH, that overlaps in the time domain with an SL transmission reserved in the time resource allocation field, the terminal 20 that originated the SL transmission may notify the destination terminal 20 or other terminals 20 of information regarding the reduction in transmission power.

[0095] Figure 19 shows an example (1) of information relating to transmission power reduction in an embodiment of the present invention. As shown in Figure 19, if the transmission power of an SL transmission is reduced by an UL transmission, i.e., PUSCH, that overlaps with a transmitted SL transmission resource in the time domain, the terminal 20 that sent the SL transmission may notify the terminal 20 that received the SL transmission or another terminal 20 of information regarding the reduction in transmission power.

[0096] At least one of the above UL transmissions and SL transmissions may be scheduled by dynamic grant. Furthermore, at least one of the above UL transmissions and SL transmissions may be configured or instructed as semi-persistent transmissions. That is, at least one of the above UL transmissions and SL transmissions may be scheduled by configured grant type 1 and configured grant type 2.

[0097] As described above, by notifying other terminals 20 of information regarding the reduction of transmission power, terminal 20 can gain a more accurate understanding of resource utilization.

[0098] Terminal 20 may perform resource allocation operations based on information received from other terminals 20 regarding reduced transmission power due to in-device coexistence.

[0099] Based on information regarding the reduction of transmission power on resources reserved by other terminals 20, terminal 20 may perform the actions shown in 1)-3) below.

[0100] 1) In the resource identification operation, if the terminal 20 receives information from another terminal 20 that a resource indicated by an SCI received from another terminal 20 has been reduced in transmission power due to the above-mentioned coexistence within the device, the terminal 20 may determine that the resource with reduced transmission power is available for use. If the terminal 20 does not receive information from another terminal 20 that a resource has been reduced in transmission power due to the above-mentioned coexistence within the device, the terminal 20 may determine that the corresponding resource is unavailable and exclude it from the group of available resource candidates. In other words, the terminal 20 may decide whether or not to use a resource based on information regarding the reduction in transmission power received from another terminal 20.

[0101] 2) Terminal 20 may determine that a resource that reduces the corresponding transmission power is available only if the power value (e.g., RSRP) of the PSCCH / PSSCH received from another terminal 20 is below or less than a predetermined value. If the power value (e.g., RSRP) of the PSCCH / PSSCH received from another terminal 20 is above or greater than a predetermined value, terminal 20 may exclude the corresponding resource from the group of available resource candidates. In other words, terminal 20 may determine whether a resource is available or not based on the power value received from another terminal 20.

[0102] 3) In the resource identification operation, terminal 20 may target a resource indicated by an SCI received from another terminal 20, subtract the amount of transmission power reduction due to the above-mentioned coexistence within the device from the power value of the PSCCH / PSSCH received from the other terminal 20 (e.g., RSRP) (for example, if a reduction of 3dB is notified, subtract 3dB from the power value), and use the transmission power value after the subtraction to determine whether the resource is available or not.

[0103] Based on information regarding the reduction of transmission power for resources already transmitted from other terminals 20, terminal 20 may perform the actions shown in 1)-3) below.

[0104] 1) In the resource identification operation, if the terminal 20 receives information from another terminal 20 that a resource indicated by an SCI received from another terminal 20 has been reduced in transmission power due to the above-mentioned coexistence within the device, the terminal 20 may determine that the resource with reduced transmission power is available for use. If the terminal 20 does not receive information from another terminal 20 that a resource has been reduced in transmission power due to the above-mentioned coexistence within the device, the terminal 20 may determine that the corresponding resource is unavailable and exclude it from the group of available resource candidates. In other words, the terminal 20 may decide whether or not to use a resource based on information regarding the reduction in transmission power received from another terminal 20.

[0105] 2) Terminal 20 may determine that a resource corresponding to a resource with reduced transmission power is available only if the power value (e.g., RSRP) of the PSCCH / PSSCH received from another terminal 20 is below or less than a predetermined value. If the power value (e.g., RSRP) of the PSCCH / PSSCH received from another terminal 20 is above or greater than a predetermined value, terminal 20 may exclude the corresponding resource from the group of available resource candidates. In other words, terminal 20 may determine whether a resource is available or not based on the power value received from another terminal 20.

[0106] 3) In the resource identification operation, terminal 20 may target a resource indicated by an SCI received from another terminal 20, and add the amount of transmission power reduction due to the above-mentioned coexistence within the device to the power value of the PSCCH / PSSCH received from the other terminal 20 (e.g., RSRP) (for example, if a reduction of 3dB is notified, 3dB is added to the power value), and use the resulting transmission power value to determine whether the resource is usable or not.

[0107] Resource identification may also refer to the operation of determining unusable resources and removing them from the group of available candidate resources. Furthermore, the above-mentioned terminal 20 is not limited to being a destination for SL transmissions from other terminals 20, and may also be the target of groupcasts or broadcasts by other terminals 20.

[0108] As described above, terminal 20 can perform resource selection based on the actual predicted received power after the reduction in transmitted power, thereby improving collision avoidance performance.

[0109] The information regarding resources that have been reserved but are not intended to be used (D) above may also include information about resources that are available but will not be used, or information about resources that have become unavailable. For example, the handling of the above information may apply in the cases shown in 1)-5) below.

[0110] 1) When a resource reservation has been made, but the transport block has been successfully sent (i.e., an ACK has been received), and retransmission is no longer necessary. 2) If a resource reservation was made, but more critical SL data occurred, causing the retransmission of the first transport block to be canceled or postponed. 3) If a resource is reserved but that resource is taken by another terminal 20 (pre-emption) 4) If a resource reservation was made but the UL transmission overlapped with it, at least in the time domain, and the transmission was canceled or postponed. 5) Resource reservation was made, but the determination formula for congestion control is (Σ i≧k CR(i)≦CR Limit If transmission is canceled or postponed by (k))

[0111] Note that CR (channel occupancy ratio) is an indicator related to the resources used by the device itself, while CBR (channel busy ratio) is an indicator related to the resources used by other devices. CR(i) is the CR evaluation value in slot nN used for PSSCH transmission where the priority field in SCI is i. Limit (k) corresponds to the upper layer parameter sl-CR-Limit and is associated with the range of CBR, including priority k and CBR measured in slot nN. N is the congestion control processing time. Pre-emption may also mean that terminal 20 receives a signal from another terminal 20 notifying it of a resource it has reserved.

[0112] The information regarding the reserved but unused resources may be either information indicating the resource that will not be used, or information indicating the reason for not using it. Furthermore, the resource reservation may be made using either the time resource allocation field or the resource reservation period field in the SCI.

[0113] As described above, by receiving notifications from other terminals 20 regarding resources that have been reserved but are not scheduled to be used, it is possible to understand resource usage more accurately.

[0114] Figure 20 shows an example of information relating to unused resources in an embodiment of the present invention. Terminal 20 may perform a resource allocation operation based on information received from other terminals 20 about reserved but not intended to be used resources.

[0115] For example, as shown in Figure 20, terminal 20C may target the resources indicated by the SCI received by terminal 20B from terminal 20A based on notifications from terminal 20A or terminal 20B. Furthermore, if terminal 20A or terminal 20B notifies that the resource will not be used, terminal 20C may determine that the resource is available without removing it from the group of available candidate resources. If terminal 20A or terminal 20B does not notify that the resource will not be used, terminal 20C may determine that the resource is unavailable and remove it from the list.

[0116] Furthermore, based on the priority of the SCI received from terminal 20A and / or the priority of the SCI that terminal 20C plans to transmit, terminal 20C may determine whether the resource is available or not without excluding it from the group of available candidate resources.

[0117] As described above, by receiving notification from other terminals 20 about reserved but unused resources, terminal 20 can use the unused resources and improve resource utilization efficiency.

[0118] As described above, terminal 20 can perform resource selection operations based on information notified from other terminals 20, thereby reducing the probability of resource collisions and improving resource utilization efficiency.

[0119] In other words, in direct communication between terminals, communication quality can be improved based on information notified from other terminals.

[0120] (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.

[0121] <Base station 10> Figure 21 is a diagram showing an example of the functional configuration of a base station 10. As shown in Figure 21, 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 21 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] <Terminal 20> Figure 22 is a diagram showing an example of the functional configuration of terminal 20. As shown in Figure 22, 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 22 is merely an example. Any functional classification and functional unit names are acceptable as long as they can perform the operations according to the embodiment of the present invention.

[0126] 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.

[0127] 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.

[0128] As described in the embodiment, the control unit 240 controls D2D communication with other terminals 20. The control unit 240 also performs processing related to HARQ for D2D and DL communication. The control unit 240 also transmits information related to the HARQ response for D2D and DL communication to other terminals 20 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 the resources to be used for D2D communication from the resource selection window based on the sensing results. The control unit 240 also performs processing related to PSBCH transmission and reception for 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.

[0129] (Hardware configuration) The block diagrams (Figures 21 and 22) 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.

[0130] 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.

[0131] 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 23 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.

[0132] In the following explanation, the term "device" can be replaced with "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.

[0133] 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.

[0134] 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.

[0135] 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 21 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 22 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.

[0136] 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.

[0137] 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.

[0138] The communication device 1004 is hardware (transmitting / receiving 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 be configured to include high-frequency switches, duplexers, filters, frequency synthesizers, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the transmitting and receiving antennas, amplifier section, transmitting and receiving section, transmission path interface, etc., may be implemented by the communication device 1004. The transmitting and receiving section may be implemented in a physically or logically separated manner, with a transmitting section and a receiving section.

[0139] 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).

[0140] 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.

[0141] 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.

[0142] (Summary of the embodiments) As described above, according to an embodiment of the present invention, a terminal is provided having a receiving unit that receives information relating to direct terminal-to-terminal communication for identifying available resources from another terminal, a control unit that identifies candidate resources and selects a resource to use based on the information, and a transmitting unit that performs transmission in direct terminal-to-terminal communication using the selected resource.

[0143] With the above configuration, terminal 20 can perform resource selection operations based on information notified from other terminals 20, thereby reducing the probability of resource collisions and improving resource utilization efficiency. In other words, in direct communication between terminals, communication quality can be improved based on information notified from other terminals.

[0144] The aforementioned information may also be information relating to the reduction of transmission power due to coexistence within the device. With this configuration, terminal 20 can perform resource selection operations based on information notified from other terminals 20, thereby improving the efficiency of resource utilization.

[0145] The control unit may determine that a resource to which the transmission power reduction is applied is available, based on information relating to the reduction in transmission power caused by coexistence within the device. With this configuration, terminal 20 can perform resource selection operations based on information notified from other terminals 20, thereby improving the efficiency of resource utilization.

[0146] The aforementioned information may also be information relating to resources that are reserved but not used. With this configuration, terminal 20 can perform resource selection operations based on information notified from other terminals 20, thereby improving the efficiency of resource utilization.

[0147] The control unit may determine that unused resources among the reserved resources are available for use, based on information relating to those resources. With this configuration, terminal 20 can perform resource selection operations based on information notified from other terminals 20, thereby improving resource utilization efficiency.

[0148] Furthermore, according to an embodiment of the present invention, a communication method is provided in which a terminal performs a receiving procedure for receiving information relating to direct terminal-to-terminal communication for identifying available resources from another terminal, a control procedure for identifying candidate resources and selecting a resource to use based on the information, and a transmission procedure for performing a transmission in direct terminal-to-terminal communication using the selected resource.

[0149] With the above configuration, terminal 20 can perform resource selection operations based on information notified from other terminals 20, thereby reducing the probability of resource collisions and improving resource utilization efficiency. In other words, in direct communication between terminals, communication quality can be improved based on information notified from other terminals.

[0150] (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.

[0151] 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, RLC (Radio Link Control) signaling, PDCP (Packet Data Convergence Protocol) signaling, broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof). RRC signaling may also be called RRC messages, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc. Furthermore, the notification of information may be carried out using any channel, for example, PSCCH, PSSCH, PSFCH, PSBCH.

[0152] 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).

[0153] 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.

[0154] 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).

[0155] 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.

[0156] 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.

[0157] 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).

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] The terms “system” and “network” as used in this disclosure are interchangeable.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] A base station can accommodate one or more (e.g., three) cells. If a base station accommodates 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.

[0167] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0168] 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.

[0169] 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.

[0170] 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), etc.). 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.

[0171] 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.

[0172] 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."

[0173] 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.

[0174] The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

[0175] 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."

[0176] 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.

[0177] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] 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".

[0197] 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.

[0198] 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.

[0199] 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."

[0200] 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).

[0201] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way. [Explanation of Symbols]

[0202] 10 base station 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 devices 210 Transmitter 220 Receiver 230 Setting section 240 Control Unit 30 GNSS 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 control information from a first terminal via a control channel, The system includes a transmitting unit that transmits to the second terminal information regarding a PSFCH opportunity to avoid a collision between a first resource, which is instructed by the control information and is used by the first terminal for transmitting on a shared channel, and a second resource, which is used by the second terminal for transmitting on a shared channel. The information relating to the PSFCH opportunity is information relating to the PSFCH opportunity corresponding to the resource indicated by the time resource allocation field included in the control information, in the terminal.

2. A communication method performed by a terminal, A receiving step of receiving control information from a first terminal via a control channel, The transmission step includes transmitting to the second terminal information regarding a PSFCH opportunity to avoid a collision between a first resource, which is instructed by the control information and is used by the first terminal for transmitting on a shared channel, and a second resource, which is used by the second terminal for transmitting on a shared channel. A communication method wherein the information relating to the PSFCH opportunity is information relating to a PSFCH opportunity corresponding to a resource indicated by a time resource allocation field included in the control information.

3. A wireless communication system including a first terminal, a second terminal, and a third terminal, The first terminal transmits control information to the third terminal via the control channel. The third terminal is, The control information is received from the first terminal. The second terminal is given information regarding a PSFCH opportunity to avoid a collision between the first resource, which is instructed by the control information and is used by the first terminal for transmitting on the shared channel, and the second resource, which is used by the second terminal for transmitting on the shared channel. The second terminal receives information from the third terminal regarding the PSFCH opportunity to avoid the collision. A wireless communication system in which the information relating to the PSFCH opportunity is information relating to a PSFCH opportunity corresponding to a resource indicated by a time resource allocation field included in the control information.

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