Terminal and communication method

Abstract

To flexibly set a resource to be sensed in inter-terminal direct communication.SOLUTION: A terminal includes a controller configured to determine whether to use one latest sensing occasion or two latest sensing occasions corresponding to a set periodicity as k sensing occasions at a time point before a candidate slot that is a resource selection target, and select a resource from the candidate slot based on a result of partial sensing in the determined k sensing occasions, and a transmitter configured to transmit at least one of a control channel or a shared channel for terminal-to-terminal communication using the selected resource.SELECTED DRAWING: Figure 17

Description

[Technical Field]

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

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

[0003] D2D reduces traffic between terminals and base stations and enables communication between terminals even when the base station becomes unavailable due to a disaster or other reason. Although 3GPP (3rd Generation Partnership Project) refers to D2D as a "sidelink," the more general term D2D is used in this specification. However, in the description of the embodiments described below, sidelink is also used as needed.

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

[0005] [Non-Patent Document 1] 3GPP TS 38.211 V16.4.0(2020-12) [Non-patent document 2] 3GPP TR 22.886 V15.1.0(2017-03) Summary of the Invention [Problem to be solved by the invention]

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

[0007] When a terminal autonomously performs resource selection through partial sensing, it is necessary to perform resource exclusion through sensing to avoid resource collisions, while at the same time reducing the number of sensing slots to save power. Therefore, it is desirable to be able to flexibly set the sensing slots according to the situation.

[0008] The present invention has been made in view of the above points, and has as its object to flexibly set sensing resources in direct communication between terminals. [Means for solving the problem]

[0009] According to the disclosed technology, a terminal is provided that has: a control unit that determines whether to use the most recent sensing opportunity or the most recent two sensing opportunities corresponding to a set periodicity as k sensing opportunities at a time point prior to a candidate slot for which resources are to be selected; and selects resources from the candidate slots based on the results of partial sensing in the determined k sensing opportunities; and a transmission unit that transmits at least one of a control channel or a shared channel for terminal-to-terminal communication using the selected resources. [Effects of the Invention]

[0010] According to the disclosed technology, sensing resources can be flexibly set in direct communication between terminals. [Brief explanation of the drawings]

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

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

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

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

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

[0016] Figure 1 is a diagram for explaining V2X. 3GPP is studying the realization of V2X (Vehicle to Everything) or eV2X (enhanced V2X) by extending D2D functions, and is currently working on specifications. As shown in Figure 1, V2X is part of ITS (Intelligent Transport Systems) and is a collective term for V2V (Vehicle to Vehicle), which refers to a form of communication between vehicles; V2I (Vehicle to Infrastructure), which refers to a form of communication between vehicles and roadside units (RSUs) installed on the side of the road; V2N (Vehicle to Network), which refers to a form of communication between vehicles and ITS servers; and V2P (Vehicle to Pedestrian), which refers to a form of communication between vehicles and mobile terminals carried by pedestrians.

[0017] Additionally, 3GPP is studying V2X using LTE or NR cellular communications and device-to-device communications. V2X using cellular communications is also called cellular V2X. NR V2X is being studied to achieve high capacity, low latency, high reliability, and quality of service (QoS) control.

[0018] It is expected that future studies of LTE or NR V2X will be conducted beyond the 3GPP specifications, including ensuring interoperability, reducing costs through implementation of higher layers, using or switching between multiple RATs (Radio Access Technologies), complying with regulations in each country, and methods for acquiring, distributing, managing databases, and using data from LTE or NR V2X platforms.

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

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

[0021] Furthermore, with regard to SL or UL Orthogonal Frequency Division Multiplexing (OFDM), any of CP-OFDM (Cyclic-Prefix OFDM), DFT-S-OFDM (Discrete Fourier Transform - Spread - OFDM), non-transform precoded OFDM, and transform precoded OFDM may be applied.

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

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

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

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

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

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

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

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

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

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

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

[0033] In addition, it is expected that NR-V2X will support hybrid automatic repeat request (HARQ) for sidelink unicast and groupcast. Furthermore, NR-V2X will define sidelink feedback control information (SFCI) including an HARQ response. Furthermore, it is being considered to transmit the SFCI via a physical sidelink feedback channel (PSFCH).

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

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

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

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

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

[0039] The terminal 20 does not need to be a device in a single housing. For example, even if various sensors are distributed and arranged inside a vehicle, the terminal 20 may be a device including the various sensors.

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

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

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

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

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

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

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

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

[0048] If HARQ control involving HARQ feedback is not performed, steps S104 and S105 may not be performed.

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

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

[0051] In steps S202 and S203, 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 frequency resources adjacent to the frequency resources of the PSSCH in the same time resources as at least a part of the time resources of the PSSCH.

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

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

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

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

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

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

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

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

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

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

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

[0063] FIG. 13 is a sequence diagram showing an operation example (4) of V2X. As described above, in the NR sidelink, it is supported that an HARQ response is transmitted on a PSFCH. Note that the PSFCH format may be the same as, for example, 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 ACKs and NACKs are identified by differences in sequence and / or cyclic shifts. The PSFCH format is not limited to this. The PSFCH resource may be allocated to the last symbol or the last multiple symbols of a slot. Furthermore, a period N is set or predefined for the PSFCH resource. The period N may be set or predefined on a slot-by-slot basis.

[0064] In FIG. 13, the vertical axis corresponds to the frequency domain, and the horizontal axis corresponds to the time domain. The PSCCH may be placed in the first symbol of a slot, or in multiple symbols from the first, or in multiple symbols from a symbol other than the first. The PSFCH may be placed in the last symbol of a slot, or in multiple symbols from the last. Note that the above-mentioned "first symbol of a slot" and "last symbol of a slot" may not take into account symbols for AGC (Automatic Gain Control) and symbols for transmission / reception switching. That is, for example, when one slot is composed of 14 symbols, the "first symbol of a slot" and the "last symbol of a slot" may refer to the first and last symbols, respectively, of the 12 symbols excluding the first and last symbols. In the example shown in FIG. 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 arrow from the PSSCH to the PSFCH indicates an example of a PSFCH associated with the PSSCH.

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

[0066] FIG. 14 is a diagram illustrating an example of sensing operation in NR. In resource allocation mode 2, a terminal 20 selects a resource and performs transmission. As shown in FIG. 14, the terminal 20 performs sensing in a sensing window within a resource pool. Through sensing, the terminal 20 receives a resource reservation field or a resource assignment field included in an SCI transmitted from another terminal 20, and identifies available resource candidates within a resource selection window within the resource pool based on the field. Then, the terminal 20 randomly selects a resource from the available resource candidates.

[0067] 14, the resource pool configuration may have a period. For example, the period may be a period of 10240 milliseconds. SLFrom slot t Tmax-1 SL In this example, the resource pool is set up to the period. The resource pool in each period may have an area set by, for example, a bitmap.

[0068] Also, as shown in FIG. 14, the transmission trigger in terminal 20 occurs in slot n, and the priority of the transmission is p TX The terminal 20 receives data from slot n-T0 to slot nT proc,0 In the sensing window up to the slot immediately before the priority p RX When an SCI is detected within the sensing window and the RSRP (Reference Signal Received Power) is greater than a threshold, the resource in the resource selection window corresponding to the SCI is excluded. When an SCI is detected within the sensing window and the RSRP is less than a threshold, the resource in the resource selection window corresponding to the SCI is not excluded. The threshold is, for example, a value determined by the priority p TX and priority p RX A threshold Th is set or defined for each resource in the sensing window based on pTX,pRX may be.

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

[0070] In the resource selection window from slot n+T1 to slot n+T2, resources occupied by other UEs are identified, and the remaining resources are available resource candidates, excluding the identified resources, as shown in Figure 14. The set of available resource candidates is denoted as S A Then, S AIf the threshold Th is set for each resource in the sensing window, pTX,pRX The threshold Th may be increased by 3 dB and resource identification may be performed again. pTX,pRX By increasing the number of resources that are not excluded because their RSRP is less than the threshold, the set of resource candidates S A may be set to be 20% or more of the resource selection window. A If the threshold Th is set for each resource in the sensing window, pTX,pRX The operation of increasing the signal level by 3 dB and performing resource identification again may be repeated.

[0071] The lower layer of the terminal 20 is S A The upper layer of the terminal 20 may report S A The terminal 20 may perform a random selection on the resources to be used. The terminal 20 may perform sidelink transmission using the determined resources.

[0072] In the above-mentioned Figure 14, the operation of the transmitting terminal 20 is explained, but the receiving terminal 20 may detect data transmission from another terminal 20 based on the results of sensing or partial sensing, and receive data from the other terminal 20.

[0073] FIG. 15 is a flowchart showing an example of preemption in NR. FIG. 16 is a diagram showing an example of preemption in NR. In step S501, terminal 20 performs sensing in a sensing window. When terminal 20 performs a power saving operation, sensing may be performed in a predefined limited period. Next, terminal 20 identifies each resource in the resource selection window based on the sensing result and generates a set of resource candidates S A Then, the terminal 20 determines a set of resource candidates S AA resource set (r_0, r_1, . . . ) for determining preemption is selected from the resource set (r_0, r_1, . . . ) (S503). The resource set may be notified to the PHY layer from an upper layer as the resource for determining whether preemption has occurred.

[0074] In step S504, the terminal 20 re-identifies each resource in the resource selection window based on the sensing result at the timing T(r_0)-T3 shown in FIG. 16 to generate a set S of resource candidates. A , and further determines whether to preempt the resource set (r_0, r_1, . . . ) based on the priority. For example, in the case of r_1 shown in FIG. 16, an SCI transmitted from another terminal 20 is detected by re-sensing, and S A When preemption is enabled, if the value prio_RX indicating the priority of the SCI transmitted from another terminal 20 is lower than the value prio_TX indicating the priority of the transport block transmitted from the terminal itself, the terminal 20 determines that the resource r_1 has been preempted. Note that the lower the value indicating the priority, the higher the priority. In other words, if the value prio_RX indicating the priority of the SCI transmitted from another terminal 20 is higher than the value prio_TX indicating the priority of the transport block transmitted from the terminal itself, the terminal 20 determines that the resource r_1 has been preempted. A , pl8), this priority is set as prio_pre. At this time, if the value prio_RX indicating the priority of the SCI transmitted from the other terminal 20 is lower than prio_pre and prio_RX is lower than the value prio_TX indicating the priority of the transport block transmitted from the terminal itself, the terminal 20 determines that the resource r_1 has been preempted.

[0075] In step S505, if preemption is determined in step S504, the terminal 20 notifies the upper layer of preemption, causes the upper layer to reselect resources, and ends the preemption check.

[0076] In addition, when re-evaluation is performed instead of checking preemption, in the above step S504, the set S of resource candidates is A After determining S A If the resource set (r_0, r_1,...) is not included in the resource set, the resource is not used and a resource reselection is performed in the upper layer.

[0077] FIG. 17 is a diagram showing an example of partial sensing operation in LTE. When partial sensing is configured from a higher layer in the LTE sidelink, terminal 20 selects resources and performs transmission as shown in FIG. 17. As shown in FIG. 17, terminal 20 performs partial sensing on a part of the sensing window in the resource pool, i.e., a sensing target. With partial sensing, terminal 20 receives a resource reservation field included in an SCI transmitted from another terminal 20, and identifies available resource candidates in the resource selection window in the resource pool based on the field. Then, terminal 20 randomly selects a resource from the available resource candidates.

[0078] FIG. 17 shows the subframe t0 SL From subframe t Tmax-1 SL In this example, the resource pool is set up to subframe n+T1. The target area of ​​the resource pool may be set by, for example, a bitmap. As shown in FIG. 17, it is assumed that a transmission trigger occurs in subframe n in terminal 20. As shown in FIG. 17, among subframe n+T1 to subframe n+T2, the target area of ​​the resource pool is set up to subframe n+T3. y1 SL From subframe t yY SLY subframes up to may be set as the resource selection window.

[0079] The terminal 20 receives a subframe t y1-k×Pstep SL From subframe t yY-k×Pstep SL It is possible to detect, for example, that another terminal 20 is transmitting in one or more sensing targets up to subframe t. k may be determined by, for example, a 10-bit bitmap. FIG. 17 shows an example in which the third and sixth bits of the bitmap are set to "1" indicating that partial sensing is performed. That is, in FIG. 17, y1-6×Pstep SL From subframe t yY-6×Pstep SL Up to and subframe t y1-3×Pstep SL From subframe t yY-3×Pstep SL As mentioned above, the k-th bit of the bitmap is set as the sensing target for subframe t. y1-k×Pstep SL From subframe t yY-k×Pstep SL It may correspond to a sensing window up to y i corresponds to the index (1...Y) in the Y subframe.

[0080] Note that k is set as a 10-bit bitmap or is predefined, and P step However, when SL communication is performed on DL and UL carriers, P step may be (U / (D+S+U))*100ms, where U corresponds to the number of UL subframes, D corresponds to the number of DL subframes, and S corresponds to the number of special subframes.

[0081] When an SCI is detected in the sensing target and the RSRP is greater than a threshold, the resource in the resource selection window corresponding to the resource reservation field of the SCI is excluded. When an SCI is detected in the sensing target and the RSRP is less than a threshold, the resource in the resource selection window corresponding to the resource reservation field of the SCI is not excluded. The threshold may be, for example, a sender priority p TX and receiver priority p RX Based on this, a threshold Th is set or defined for each resource in the sensing target. pTX,pRX may be.

[0082] As shown in Fig. 17, in a resource selection window set in the Y subframe of the section [n+T1, n+T2], the terminal 20 identifies resources occupied by other UEs, and the resources excluding these resources become available resource candidates. Note that the Y subframes do not have to be consecutive. A set of available resource candidates is denoted as S A Then, S A If the resource selection window is less than 20% of the resources, the threshold Th set for each sensing target resource is pTX,pRX may be increased by 3 dB and resource identification performed again.

[0083] That is, the threshold value Th pTX,pRX By increasing S and performing resource identification again, the number of resources that are not excluded because their RSRP is below the threshold may be increased. A Measure the RSSI of each resource in the set S and select the resources with the smallest RSSI. B The set of resource candidates S B S until is greater than or equal to 20% of the resource selection window. A The resource with the smallest RSSI included in B The operation of adding to may be repeated.

[0084] The lower layer of the terminal 20 is S B The upper layer of the terminal 20 may report SB The terminal 20 may determine the resource to be used by randomly selecting the resource. The terminal 20 may perform sidelink transmission using the determined resource. Note that after once reserving the resource, the terminal 20 may select the resource a predetermined number of times (e.g., C resel The resource may be used periodically without sensing for a certain period of time (times).

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

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

[0087] For example, as a resource allocation method for the sidelink, the terminal 20 may perform full sensing as shown in Fig. 14. Alternatively, the terminal 20 may perform partial sensing, in which the terminal 20 identifies resources by sensing only limited resources compared to full sensing, and selects resources from the identified resource set. Alternatively, the terminal 20 may perform random selection, in which the terminal 20 sets the resources in the resource selection window as an identified resource set without excluding resources from the resources in the resource selection window, and selects resources from the identified resource set.

[0088] Note that a method of performing random selection at the time of resource selection and using sensing information at the time of reevaluation or preemption check may be treated as partial sensing or as random selection.

[0089] As the sensing operation, the following 1) and 2) may be applied.

[0090] 1)Periodic-based partial sensing In a mechanism where sensing is performed only on some slots, an operation of determining sensing slots based on a reservation periodicity. The reservation period is a value related to a resource reservation period field. The period may be replaced with periodicity.

[0091] 2) Contiguous partial sensing In a mechanism for sensing only some slots, an operation of determining sensing slots based on aperiodic reservation, where the aperiodic reservation is a value associated with a time resource assignment field.

[0092] Release 17 may specify the operation assuming three types of terminals 20. One is Type A, which does not have the capability to receive any sidelink signals and channels, with the possible exception of receiving PSFCH and S-SSB.

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

[0094] The other is Type D, and a Type D terminal 20 has the capability to receive all sidelink signals and channels defined in Release 16, but does not exclude receiving some sidelink signals and channels.

[0095] It should be noted that UE types other than the above-mentioned Type A, Type B, and Type D may be envisaged, and the UE type and the UE capabilities may or may not be associated with each other.

[0096] In Release 17, multiple resource allocation methods can be configured for a resource pool. Also, as a power-saving feature, SL-DRX (Discontinuous Reception) is supported. In other words, reception is performed only during a specified time interval.

[0097] As described above, partial sensing is supported as one of the power saving functions. In a resource pool in which partial sensing is configured and periodic reservation is enabled, the terminal 20 may perform the above-mentioned periodic partial sensing. The periodic reservation may be a reservation for transmitting another transport block. The terminal 20 may receive information from the base station 10 for configuring a resource pool in which partial sensing is configured and periodic reservation is enabled.

[0098] Fig. 18 is a diagram for explaining an example (1) of partial sensing in an embodiment of the present invention. As shown in Fig. 18, when the trigger for resource selection is slot n, terminal 20 selects Y candidate slots for resource selection from the resource selection window [n+T1, n+T2]. Fig. 18 shows an example in which Y=7. As shown in Fig. 18, the beginning of Y candidate slots is slot t SL y1 Then, the next slot is t SL y2 , the next slot is t SL y3 , the next slot is t SLy4 , the next slot is t SL y5 , the next slot is t SL y6 , the end of slot t SL y7 Let's say.

[0099] FIG. 19 is a diagram for explaining an example (2) of partial sensing in the embodiment of the present invention. The terminal 20 is SL y-k×Preserve However, t SL y is included in the Y candidate slots. That is, in the example shown in FIG. SL y1 From t SL y7 The sensing target slot t corresponds to SL y1-k×Preserve From t SL y7-k×Preserve The setting is up to P reserve P may be a periodic value relating to the period during which resource reservations are permitted in the resource pool. reserve may be determined based on the upper layer parameter sl-ResourceReservePeriodList. Note that Fig. 19 shows the case where k is one value, and when multiple k are set, the number of slots to be sensed may increase by each k.

[0100] t SL y-k×Preserve k in may be set as shown in 1)-6) below.

[0101] 1) One k corresponding to only the most recent sensing opportunity corresponding to the set reservation period at a time point prior to the resource selection trigger or Y candidate slots. Note that the sensing opportunity may be determined taking into account a processing time limit. For example, the sensing opportunity may be prior to the processing time limit. Furthermore, the processing time limit may be a limit related to the resource selection trigger or a limit related to the Y candidate slots. 2) Two k's corresponding to the two most recent sensing opportunities corresponding to the set reservation period at a time point prior to the resource selection trigger or Y candidate slots. The sensing opportunities may be determined taking into account a processing time limit. For example, the sensing opportunities may be determined to be prior to the processing time limit. The processing time limit may be a limit related to the resource selection trigger or a limit related to the Y candidate slots. 3) All sensing occasions after the beginning of the sensing window n-T0, where T0 may be determined by the upper layer parameter sl-SensingWindow. 4) Only one periodic sensing opportunity for one reservation period. k may be determined based on UE implementation, or a maximum value may be specified or set. 5) One or more k may be set. 6) A bitmap corresponding to the value of k is set, as in the partial sensing in LTE-V2X shown in Fig. 17. The bitmap may be, for example, 10 bits long, with 1 representing a sensing opportunity that is a sensing target and 0 representing a sensing opportunity that is not a sensing opportunity. 7) k may be determined in other ways.

[0102] When a terminal autonomously selects resources using partial sensing, it must perform resource exclusion through sensing to avoid resource conflicts, but it must also reduce the number of sensing targets to save power. Therefore, it is desirable to be able to flexibly set the sensing targets according to the situation.

[0103] Therefore, the terminal 20 may determine the sensing target as shown in A) to D) below.

[0104] A) t by K k corresponding to the latest K sensing opportunities corresponding to the set reservation period at a time point before the processing time limit for the resource selection trigger or the processing time limit for Y candidate slots SL y-k×Preserve are set as sensing targets. The value of K may be set or may be predefined. The value of K may also be determined based on the priority or the reservation period associated with the data to be transmitted.

[0105] B) At least one of the k setting methods shown in 1)-6) above may be defined as a candidate k setting method, and one k setting method may be selected from the candidates based on settings or priorities.

[0106] C) Of the setting methods 1)-6), A) and D), a different setting method for k may be applied for each set period. For example, the method 2) above may be applied when the period is equal to or less than a predetermined value, and the method 1) above may be applied when the period is equal to or greater than a predetermined value.

[0107] D) In ​​5) or 6), k may be set to include the most recent sensing opportunity. The most recent sensing opportunity refers to the most recent sensing opportunity corresponding to the set reservation period at a time point prior to the resource selection trigger or the Y candidate slot. The sensing opportunity may be determined taking into account a processing time limit. For example, the sensing opportunity may be set to be prior to the processing time limit. The processing time limit may be a limit related to the resource selection trigger or a limit related to the Y candidate slot.

[0108] 20 is a flowchart for explaining an example of partial sensing in an embodiment of the present invention. In step S601, a terminal 20 performing periodic partial sensing is configured by the base station 10 with a resource pool in which partial sensing is configured and a resource pool in which periodic reservation is enabled. In the following step S602, the terminal 20 SL y-k×Preserve The periodic partial sensing is performed on t SL y is included in the Y candidate slots.

[0109] The terminal 20 is SL y-k×Preserve may be determined as shown in A)-D) above, partial sensing may be performed, resource exclusion may be performed in Y candidate slots, and then resources may be selected for sidelink transmission to other terminals 20.

[0110] The above-described embodiment may be applied to an operation in which one terminal 20 configures or allocates transmission resources for another terminal 20.

[0111] The above-described embodiment is not limited to V2X terminals, and may be applied to terminals that perform D2D communication.

[0112] The operations according to the above-described embodiment may be performed only in a specific resource pool, for example, only in a resource pool that can be used by terminals 20 of Release 17 or later.

[0113] According to the above-described embodiment, the terminal 20 can appropriately control the trade-off between the resource exclusion performance and the amount of resources to be sensed, depending on the required performance.

[0114] That is, in direct communication between terminals, the sensing resources can be flexibly set.

[0115] (Device configuration) Next, a description will be given of an example of the functional configuration of the base station 10 and the terminal 20 that execute the processes and operations described above. The base station 10 and the terminal 20 include functions for implementing the above-described embodiments. However, the base station 10 and the terminal 20 may each include only a part of the functions of the embodiments.

[0116] <Base station 10> Fig. 21 is a diagram showing an example of the functional configuration of base station 10. As shown in Fig. 21, base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 21 is merely an example. The names of the functional divisions and functional units may be any as long as they can perform the operations related to the embodiment of the present invention.

[0117] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signals. The transmitter 110 also has a function of transmitting an NR-PSS, an NR-SSS, an NR-PBCH, a DL / UL control signal, a DL reference signal, etc. to the terminal 20.

[0118] The setting unit 130 stores in a storage device setting information that is set in advance and various setting information to be transmitted to the terminal 20, and reads out from the storage device as needed. The content of the setting information is, for example, information related to the setting of D2D communication.

[0119] As described in the embodiments, the control unit 140 performs processing related to settings for the terminal 20 to perform D2D communication. Furthermore, the control unit 140 transmits scheduling for D2D communication and DL communication to the terminal 20 via the transmission unit 110. Furthermore, the control unit 140 receives information related to HARQ responses for D2D communication and DL communication from the terminal 20 via the reception unit 120. A functional unit related to signal transmission in the control unit 140 may be included in the transmission unit 110, and a functional unit related to signal reception in the control unit 140 may be included in the reception unit 120.

[0120] <Terminal 20> Fig. 22 is a diagram showing an example of the functional configuration of terminal 20. As shown in Fig. 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 Fig. 22 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention.

[0121] The transmitter 210 creates a transmission signal from transmission data and transmits the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires a higher layer signal from the received physical layer signal. The receiver 220 also has a function of receiving an NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signal, reference signal, or the like transmitted from the base station 10. For example, the transmitter 210 transmits a PSCCH (Physical Sidelink Control Channel), a PSSCH (Physical Sidelink Shared Channel), a PSDCH (Physical Sidelink Discovery Channel), a PSBCH (Physical Sidelink Broadcast Channel), or the like to another terminal 20 as D2D communication, and the receiver 220 receives the PSCCH, PSSCH, PSDCH, or PSBCH, or the like, from the other terminal 20.

[0122] The setting unit 230 stores various setting information received from the base station 10 or the terminal 20 by the receiving unit 220 in a storage device and reads it from the storage device as needed. The setting unit 230 also stores setting information that is set in advance. The content of the setting information is, for example, information related to the setting of D2D communication.

[0123] As described in the embodiments, the control unit 240 controls D2D communication for establishing an RRC connection with another terminal 20. The control unit 240 also performs processing related to power saving operation. The control unit 240 also performs processing related to HARQ for D2D communication and DL communication. The control unit 240 also transmits information related to HARQ responses for D2D communication and DL communication to another terminal 20 scheduled by the base station 10 to the base station 10. The control unit 240 may also schedule D2D communication for another terminal 20. The control unit 240 may also autonomously select resources to be used for D2D communication from a resource selection window based on a sensing result, or may perform re-evaluation or preemption. The control unit 240 also performs processing related to power saving in transmission and reception of D2D communication. The control unit 240 also performs processing related to inter-terminal coordination in D2D communication. A functional unit related to signal transmission in the control unit 240 may be included in the transmission unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the reception unit 220.

[0124] (Hardware configuration) The block diagrams (FIGS. 21 and 22) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or the multiple devices.

[0125] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

[0126] For example, the base station 10, the terminal 20, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 23 is a diagram illustrating an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The base station 10 and the terminal 20 described above 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.

[0127] In the following description, the term "apparatus" can be read as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0128] Each function in the base station 10 and the terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001, the memory device 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls at least one of reading and writing data in the memory device 1002 and the auxiliary memory device 1003.

[0129] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0130] Furthermore, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 140 of the base station 10 shown in FIG. 21 may be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. Furthermore, for example, the control unit 240 of the terminal 20 shown in FIG. 22 may be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. While the above-described various processes have been described as being executed by one processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0131] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0132] The secondary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0133] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0134] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0135] 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 may be configured using different buses between each device.

[0136] Furthermore, base station 10 and terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, processor 1001 may be implemented using at least one of these pieces of hardware.

[0137] (Summary of the embodiment) As described above, according to an embodiment of the present invention, a terminal is provided which includes a receiving unit that receives signals from other terminals in a resource pool in which partial sensing is set and periodic reservation is enabled, a control unit that determines candidate resources for selecting resources in the resource pool from a resource selection window, determines resources to be sensed that correspond to the candidate resources, and identifies the candidate resources based on the sensing results of the resources to be sensed to determine usable resources, and a transmitting unit that transmits to other terminals using the determined resources, wherein the control unit determines at least one of one or more latest sensing opportunities that correspond to the period of the periodic reservation at a time prior to a processing time limit as the resource to be sensed.

[0138] With the above configuration, terminal 20 can appropriately control the trade-off between resource exclusion performance and the amount of resources to be sensed, depending on the required performance. That is, in direct terminal-to-terminal communication, the resources to be sensed can be flexibly set.

[0139] The processing time limit may be a limit on the processing time for a resource selection trigger or a limit on the processing time for the candidate resource. With this configuration, the terminal 20 can appropriately control the trade-off between the performance of resource exclusion and the amount of resources to be sensed in accordance with the required performance while ensuring the processing time.

[0140] The control unit may change the number of the one or more latest sensing opportunities determined as the resource to be sensed. With this configuration, the terminal 20 can appropriately control the trade-off between the performance of resource exclusion and the amount of the resource to be sensed, depending on the required performance.

[0141] The control unit may determine the resources to be sensed based on a bitmap indicating which sensing opportunities are to be sensed or which sensing opportunities are not to be sensed, among the one or more latest sensing opportunities. With this configuration, the terminal 20 can appropriately control the trade-off between the performance of resource exclusion and the amount of resources to be sensed, depending on the required performance.

[0142] Furthermore, according to an embodiment of the present invention, there is provided a communication method in which a terminal executes a procedure for determining, as the resource to be sensed, at least one of one or more latest sensing opportunities corresponding to the periodic reservation cycle at a point in time prior to a processing time limit, as the resource to be sensed, the method comprising: a receiving procedure for receiving signals from other terminals in a resource pool in which partial sensing is set and periodic reservation is enabled; a control procedure for determining candidate resources in the resource pool from a resource selection window, determining resources to be sensed that correspond to the candidate resources, and identifying the candidate resources based on the sensing results of the resources to be sensed to determine usable resources; and a transmitting procedure for transmitting to another terminal using the determined resources.

[0143] With the above configuration, terminal 20 can appropriately control the trade-off between resource exclusion performance and the amount of resources to be sensed, depending on the required performance. That is, in direct terminal-to-terminal communication, the resources to be sensed can be flexibly set.

[0144] (Supplementary explanation of the embodiment) Although the 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, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, 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; two or more items may be combined as needed, and items described in one item may apply to items described in another item (unless inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of the processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams. However, such devices may be implemented using hardware, software, or a combination thereof. The software operated by the processor of the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each 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.

[0145] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0146] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-Advanced (LTE-A), 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), or other appropriate systems, and next-generation systems extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0147] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order and are not limited to the particular order presented.

[0148] In this specification, a specific operation that is described as being performed by the base station 10 may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and another network node other than the base station 10 (such as, but not limited to, an MME or an S-GW). Although the above example illustrates a case where there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (such as an MME and an S-GW).

[0149] The information or signals described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0150] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be sent to another device.

[0151] In the present disclosure, the determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0152] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0153] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0154] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0155] Note that terms explained 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 a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0156] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0157] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0158] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0159] In this disclosure, terms such as "base station (BS)," "radio base station," "base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0160] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication service within this coverage.

[0161] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0162] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0163] 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, or the mobile body itself. 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 also include devices that do not necessarily move during communication operations. 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.

[0164] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between a plurality of terminals 20 (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0165] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0166] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0167] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0168] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0169] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0170] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0171] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0172] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0173] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0174] Numerology may be communication parameters that apply to at least one of transmission and reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0175] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may be a time unit based on numerology.

[0176] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot 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.

[0177] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0178] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc. instead of a subframe.

[0179] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0180] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0181] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0182] A TTI having a time length of 1 ms may be called a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0183] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0184] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may also be determined based on numerology.

[0185] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0186] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, or the like.

[0187] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0188] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0189] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be set for the terminal 20 within one carrier.

[0190] At least one of the configured BWPs may be active, and the terminal 20 may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell," "carrier," and the like in this disclosure may be read as "BWP."

[0191] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0192] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0193] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0194] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0195] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0196] <Additional Notes> The above-described embodiment can be further described as follows.

[0197] (Appendix 1) a receiving unit that receives signals from other terminals in a resource pool in which partial sensing is configured and periodic reservation is enabled; a control unit that determines candidate resources for selecting resources in the resource pool from a resource selection window, determines sensing target resources corresponding to the candidate resources, and identifies the candidate resources based on sensing results of the sensing target resources to determine usable resources; a transmitting unit that transmits to another terminal using the determined resource; The control unit determines at least one of the one or more latest sensing opportunities corresponding to the periodic reservation cycle at a point in time prior to the processing time limit as the resource to be sensed.

[0198] (Appendix 2) 2. The terminal according to claim 1, wherein the processing time limit is a processing time limit for a resource selection trigger or a processing time limit for the candidate resource.

[0199] (Appendix 3) 3. The terminal according to claim 2, wherein the control unit changes the number of the one or more latest sensing opportunities determined as the sensing target resource.

[0200] (Appendix 4) The terminal of claim 2, wherein the control unit determines the sensing target resources based on a bitmap indicating sensing opportunities to be sensed or sensing opportunities not to be sensed among the one or more latest sensing opportunities.

[0201] (Appendix 5) a receiving procedure for receiving signals from other terminals in a resource pool in which partial sensing is configured and periodic reservation is enabled; a control procedure for determining candidate resources for resource selection in the resource pool from a resource selection window, determining sensing target resources corresponding to the candidate resources, and identifying the candidate resources based on sensing results of the sensing target resources to determine available resources; a transmission procedure for transmitting to another terminal using the determined resource; A communication method in which a terminal executes a procedure to determine at least one of the most recent sensing opportunities corresponding to the periodic reservation cycle at a point in time prior to the processing time limit as the resource to be sensed. [Explanation of symbols]

[0202] 10 base station 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 terminals 210 Transmitter 220 Receiving unit 230 Setting Section 240 Control Unit 1001 processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output Device

Claims

1. a control unit that determines whether to use the most recent one sensing opportunity or the most recent two sensing opportunities corresponding to the set periodicity as k sensing opportunities at a time point prior to a candidate slot from which resources are to be selected, and selects a resource from the candidate slot based on partial sensing results in the determined k sensing opportunities; a transmitter that transmits at least one of a control channel or a shared channel for terminal-to-terminal communication using the selected resource; A terminal having:

2. The setting information is preset or received from a base station or another terminal. The terminal of claim 1.

3. The control unit determines timings of the k sensing opportunities based on a processing time limit of the terminal. The terminal of claim 1.

4. 4. The terminal according to claim 3, wherein the processing time limit is a processing time limit for a resource selection trigger and a processing time limit for the candidate slot.

5. The periodicity is a value of periodicity for which resource reservation is allowed in a resource pool. The terminal of claim 1.

6. Further comprising a receiving unit that detects control information transmitted from another terminal by the partial sensing in the k sensing opportunities. The terminal of claim 1.

7. a step of determining whether to use the most recent one sensing opportunity or the most recent two sensing opportunities corresponding to the set periodicity as k sensing opportunities at a time point prior to the candidate slot from which resources are to be selected, and selecting a resource from the candidate slot based on partial sensing results in the determined k sensing opportunities; transmitting at least one of a control channel and a shared channel for terminal-to-terminal communication using the selected resource; A communication method implemented by a terminal.

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