Terminal and communication method

Abstract

To perform communication using carrier aggregation in direct communication between terminals.SOLUTION: A terminal includes a control unit that, when selecting carriers for transmitting sidelink data, selects target carriers and resource pools associated with the target carriers based on the channel busy ratios (CBRs) of the target carriers and the priority of a sidelink logical channel, and a transmitting unit that performs transmission in sidelink communication via the selected multiple carriers in the same time unit.SELECTED DRAWING: Figure 20

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 V16.7.0(2021-09) [Non-patent document 2] 3GPP TR 22.886 V15.1.0(2017-03) [Non-patent document 3] 3GPP TS 38.214 V16.7.0(2021-09) [Non-patent document 4] 3GPP TS 38.331 V16.6.0(2021-09) Summary of the Invention [Problem to be solved by the invention]

[0006] The application of carrier aggregation has been considered as an enhancement to the NR sidelink. However, if the same operation as carrier aggregation in conventional technologies is performed, it may be difficult to achieve the required quality and may not support the functions specified for the NR sidelink.

[0007] The present invention has been made in view of the above points, and has as its object to perform communication using carrier aggregation in direct communication between terminals. [Means for solving the problem]

[0008] According to the disclosed technology, there is provided a terminal including: a control unit that, when selecting a carrier for transmitting sidelink data, selects a target carrier and a resource pool associated with the target carrier based on a Channel Busy Ratio (CBR) of the target carrier and a priority of a sidelink logical channel of the target carrier; and a transmission unit that performs transmission in sidelink communication via the selected multiple carriers in the same time unit. [Effects of the Invention]

[0009] According to the disclosed technology, communication by carrier aggregation can be performed in direct communication between terminals. [Brief explanation of the drawings]

[0010] [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. 10 is a diagram illustrating an example of periodic partial sensing. [Figure 19]FIG. 10 is a diagram for explaining an example of continuous partial sensing. [Figure 20] FIG. 1 is a diagram for explaining an example (1) of carrier selection according to an embodiment of the present invention. [Figure 21] FIG. 10 is a diagram for explaining an example (2) of carrier selection according to the embodiment of the present invention. [Figure 22] 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 23] 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 24] 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. [Figure 25] FIG. 2 is a diagram showing an example of the configuration of a vehicle 2001 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] 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.

[0013] 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.).

[0014] Furthermore, in the embodiments of the present invention, "configuring" radio parameters and the like may mean that a predetermined value is pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are set. Furthermore, in the embodiments of the present invention, "equal to or greater than" may be replaceable with "exceeds", and "equal to or less than" may be replaceable with "less than".

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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).

[0032] 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).

[0033] 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.

[0034] 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".

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] 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.

[0043] In steps S102 and S103, terminal 20A transmits SCI (Sidelink Control Information) via PSCCH and / or PSSCH using the resources autonomously selected in step S101, and 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] If HARQ control involving HARQ feedback is not performed, steps S104 and S105 may not be performed.

[0048] 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.

[0049] 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.

[0050] In steps S202 and S203, terminal 20A transmits SCI via PSCCH and / or PSSCH and transmits SL data via PSSCH using the resources autonomously selected in step S201. For example, terminal 20A may transmit PSCCH using 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.

[0051] 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.

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

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The resource information is included in the DL scheduling DCI or SL scheduling DCI transmitted from the base station 10 in step S301, and the terminal 20A 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.

[0059] 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.

[0060] 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.

[0061] If HARQ control involving HARQ feedback is not performed, step S304 and / or step S305 may not be performed.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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).

[0084] 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.

[0085] In addition, in the NR Release 17 sidelink, operation 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 account when selecting resources for transmission.

[0086] 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.

[0087] 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.

[0088] The sensing operations may be 1) and 2) shown below. Note that sensing and monitoring may be interchangeable, and the sensing operations may include at least one of measuring received RSRP, obtaining reserved resource information, and obtaining priority information.

[0089] 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.

[0090] 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.

[0091] 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, except for receiving the PSFCH and S-SSB (SS / PBCH block).

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] As described above, partial sensing is supported as one of the power saving functions. In a resource pool in which partial sensing is configured, the terminal 20 may perform the above-described periodic partial sensing. The terminal 20 may receive, from the base station 10, information for configuring a resource pool in which partial sensing is configured and periodic reservation is enabled.

[0097] 18 is a diagram illustrating an example of periodic partial sensing. As shown in FIG. 18, Y candidate slots for resource selection are selected from a resource selection window [n+T1, n+T2].

[0098] t y SL Let t be one of the Y candidate slots. y-k×Preserve SL may be used as a target slot for periodic partial sensing.

[0099] P reserve may correspond to all values ​​contained in a configured or predefined set sl-ResouceReservePeriodList. Alternatively, P may be limited to a subset of sl-ResouceReservePeriodList. reserve The value of P may be set or predefined. reserve and sl-ResouceReservePeriodList may be configured for each transmission resource pool in resource allocation mode 2. Furthermore, the UE may implement monitoring of periods included in sl-ResouceReservePeriodList other than the limited subset. For example, the terminal 20 may additionally monitor opportunities corresponding to P_RSVP_Tx.

[0100] Regarding the k value, the terminal 20 may monitor the most recent sensing opportunity in a certain reservation cycle before slot n of the resource selection trigger or before the first slot of Y candidate slots subject to processing time limitations. Furthermore, the terminal 20 may additionally monitor periodic sensing opportunities corresponding to a set of one or more k values. For example, the k value may be set to a value corresponding to the most recent sensing opportunity in a certain reservation cycle before slot n of the resource selection trigger or before the first slot of Y candidate slots subject to processing time limitations, and a value corresponding to the sensing opportunity immediately preceding the most recent sensing opportunity in the certain reservation cycle.

[0101] As described above, partial sensing is supported as one of the power saving functions. In a resource pool in which partial sensing is configured, the terminal 20 may perform the above-described continuous partial sensing. The terminal 20 may receive information from the base station 10 for configuring a resource pool in which partial sensing is configured and aperiodic reservation is enabled.

[0102] FIG. 19 is a diagram for explaining an example of continuous partial sensing. As shown in FIG. 19, 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. 19 shows an example in which Y=7. As shown in FIG. 19, the beginning of Y candidate slots is slot t y1 Then, the next slot is t y2 Let,···,the end of Y candidate slots be slot t yY It is written as follows.

[0103] The terminal 20 is connected to the section [n+T A ,n+T B ] and sensing is performed with n+T B or n+T B After (n+T C The resource selection is performed in the interval [n+T A ,n+T B ]T A and T B can be any value, and n can be replaced with the index of any of the Y candidate slots.

[0104] Furthermore, the symbol [ may be replaced with the symbol (and the symbol ] may be replaced with the symbol). For example, the interval [a, b] is the interval from slot a to slot b, and includes slot a and slot b. For example, the interval (a, b) is the interval from slot a to slot b, and does not include slot a and slot b.

[0105] The candidate resources to be selected are referred to as Y candidate slots, but all slots in the interval [n+T1, n+T2] may be candidate slots, or only some of the slots may be candidate slots.

[0106] 3GPP Release 16 now defines the initial specifications for the NR sidelink. Based on LTE-SL, the specifications are in line with the NR concept and assume V2X. The specifications support, for example, aperiodic transmission and / or periodic transmission, unicast and groupcast, HARQ feedback, 256QAM (Quadrature amplitude modulation), MIMO (Multiple input multiple output), CSI (Channel state information) reporting, single-carrier transmission, and FR1 (Frequency Range 1).

[0107] Additionally, 3GPP Release 17 is considering an extended specification for the NR sidelink from Release 16. This specification considers functions related to power-saving operation, reliability, and improved latency performance for use cases such as public safety communications and commercial communications in addition to V2X. For example, partial sensing, random resource selection for transmission, and DRX are considered for power-saving operation. For example, inter-UE coordination is considered for improving reliability and latency performance.

[0108] Further enhancements to the NR sidelink are being considered in 3GPP Release 18. These may include, for example, higher data rates, support for new frequencies, and the addition of V2X enhancements. These enhancements include sidelink carrier aggregation, unlicensed band support, FR2 support, beam management, and LTE-SL and NR-SL channel coexistence.

[0109] In carrier aggregation in LTE-SL, synchronization is achieved by referring all carriers to a certain carrier, which may be any of the carrier sets configured by higher layers.

[0110] Furthermore, in the case of scheduling by the base station 10, resource selection in carrier aggregation in LTE-SL may be performed by including a carrier indicator in the SCI. Furthermore, when the UE autonomously selects resources, a carrier may be selected for each resource selection. For example, a carrier may be selected based on the priority of a logical channel or a CBR (Channel Busy Ratio). For example, one carrier may be used for each resource selection. For example, one carrier may be used for transmitting a certain transport block. For example, after carrier selection, an independent resource selection procedure may be performed for each carrier. For example, resources that cannot be simultaneously transmitted may be excluded as the final step of resource identification (i.e., after an operation related to resource exclusion based on a reservation signal received from another terminal 20). For example, resources that cannot be simultaneously transmitted may be excluded based on the number of simultaneous transmissions, supported carrier combinations, and processing time.

[0111] Regarding power control in carrier aggregation in LTE-SL, power may be reduced based on priority so as not to exceed the maximum transmission power, or transmission may not be performed. Furthermore, in carrier aggregation in LTE-SL, packet duplication may be performed.

[0112] Here, it is necessary to determine the operation when performing carrier aggregation in NR-SL. For example, if the same operation as carrier aggregation in LTE-SL is applied, the required quality may not be met. Also, it may not be possible to support new functions introduced in NR that do not exist in LTE. Note that carrier aggregation may also mean the function of transmitting or receiving via multiple carriers in the same time unit.

[0113] Therefore, in NR-SL, the operations related to carrier aggregation described below may be performed.

[0114] 1) When the terminal 20 performs carrier aggregation in SL, the terminal 20 may select a carrier as shown in at least one of 1A)-1G) below.

[0115] 1A) The terminal 20 may select a carrier based on at least one of information related to SL-HARQ feedback (e.g., PSFCH resources), priority, periodic reservation, sensing method, IUC (Inter UE coordination), CBR, RSRP threshold (e.g., RSRP threshold for resource exclusion related to resource selection), MCS (Modulation and Coding Scheme) table, and capabilities of the destination UE.

[0116] 1B) Terminal 20 may determine a carrier as a selection candidate based on the priority of transmission data and the CBR of the carrier. For example, terminal 20 may compare a CBR threshold related to the priority of transmission data with the CBR of the carrier, and determine the carrier as a selection candidate if the CBR of the carrier does not exceed the CBR threshold.

[0117] 1C) When terminal 20 performs carrier selection for transmitting data requiring SL-HARQ feedback (hereinafter, "data" may be any of a transport block, a MAC-PDU (Protocol Data Unit), a MAC-SDU (Service Data Unit), a logical channel, etc., or may be information transmitted on a PSSCH), terminal 20 may select carriers including a resource pool in which PSFCH resources are configured or pre-configured as selection candidates.

[0118] 20 is a diagram illustrating an example (1) of carrier selection according to an embodiment of the present invention. As shown in FIG. 20, carrier a includes a resource pool a-1 in which PSFCH resources are configured, and carrier b includes a resource pool in which PSFCH resource pool b-1 is configured, and therefore terminal 20 may select carrier a and carrier b as carrier selection candidates.

[0119] For example, if the information element sl-HARQ-FeedbackEnabled is set to enabled for the logical channel, the MAC entity may select one or more carriers that include at least one resource pool with PSFCH resources configured.

[0120] By operating as described above, it is possible to avoid a case where a carrier in which no PSFCH resource is configured is selected for data that requires SL-HARQ feedback.

[0121] 1D) The terminal 20 makes a periodic reservation (e.g., P rsvp_TX When performing carrier selection for transmitting data requiring periodic reservation (sl-ResourceReservePeriodList is non-zero), terminal 20 may select carriers including a resource pool in which a value other than 0 is set in the allowed reservation periodicity (sl-ResourceReservePeriodList, for example) as selection candidates (see Non-Patent Document 3). For example, terminal 20 may select carriers including a resource pool in which the list of allowed reservation periodicities (sl-ResourceReservePeriodList) has a predetermined reservation periodicity (SL-ResourceReservePeriod) as selection candidates (see Non-Patent Document 4). For example, the predetermined reservation period may be a reservation period required for transmitting the corresponding data. By operating as described above, when transmitting data involving periodic reservation, it is possible to operate to ensure reliable transmission. Note that period and periodicity may be interpreted interchangeably.

[0122] 1E) When terminal 20 performs carrier selection for data transmission based on a predetermined sensing method and / or resource selection method, it may select carriers that include a resource pool for which the sensing method and / or resource selection method is set or pre-configured as selection candidates. For example, terminal 20 may select carriers that include a resource pool for which no method other than the predetermined sensing method and / or resource selection method is assigned as selection candidates. For example, for transmission of data that requires high reliability and / or delay performance, carriers that include a resource pool in which only full sensing is permitted and partial sensing or random selection is not permitted may be excluded from selection candidates. By operating as described above, terminal 20 can select a carrier that can use the desired sensing and / or resource selection method.

[0123] 1F) When terminal 20 performs carrier selection for transmitting data to be transmitted in a resource pool capable of implementing IUC, terminal 20 may select carriers including a resource pool in which IUC is set or preset as selection candidates. By operating as described above, terminal 20 can transmit data requiring high reliability and / or delay performance in a resource pool capable of implementing IUC.

[0124] 1G) When terminal 20 performs carrier selection for transmitting data that uses a specific MCS table, it may select carriers that include a resource pool in which that MCS table is set or preset. By operating as described above, terminal 20 can select a carrier that can use a desired MCS table.

[0125] 1H) When carrier selection is based on multiple factors among those described in 1A), the multiple factors may be applied in a predetermined order of priority and / or sequence. For example, the factors may be applied in the order shown below.

[0126] 1) Destination UE capabilities for each carrier 2) Information related to SL-HARQ feedback (e.g., PSFCH resource) 3) Sensing and / or resource selection methods 4) Priority of transmitted data and carrier CBR 5) Periodic reservations 6) IUC and / or RSRP threshold and / or MCS table

[0127] Some of the elements 1)-6) above may be applied. For example, only the top X elements may be applied. 1)-6) above may be applied in order from the top, and elements lower than a predetermined element may not be applied based on a predetermined condition (e.g., the number of candidate carriers). For example, when the number of candidate carriers reaches or falls below a predetermined value, elements lower than a predetermined element may not be applied based on the predetermined condition.

[0128] The rankings shown in 1)-6) above are examples, and any other rankings may be set.

[0129] By operating as described above, the terminal 20 can perform carrier selection based on more important factors.

[0130] 2) When the terminal 20 performs carrier aggregation in SL, it may perform a reassessment and / or preemption check as shown in at least one of 2A)-2G) below. The preemption check may be replaced with preemption. Hereinafter, "reassessment and / or preemption check" will be referred to as "reassessment / preemption check."

[0131] 2A) If the target resource for the reevaluation / preemption check exists on a single carrier, the terminal 20 may perform the reevaluation / preemption check by considering only that carrier. For example, the terminal 20 may not apply resource exclusion related to at least one of the number of simultaneous transmissions, the supported carrier combinations, and the processing time for simultaneous transmission. By operating in this manner, the reevaluation / preemption check can be performed in the same manner as in non-carrier aggregation, preventing the processing from becoming complicated.

[0132] 2B) If the resources subject to the re-evaluation / preemption check exist on a single carrier, the terminal 20 may perform the re-evaluation / preemption check taking multiple carriers into consideration. For example, if the selected or reserved resources of each carrier overlap with the selected or reserved resources of another carrier and are determined to be unavailable for transmission due to at least one of the factors of the number of simultaneous transmissions, the supported carrier combinations, and the processing time for simultaneous transmissions, the re-evaluation / preemption check may be notified from the PHY to the MAC. "The re-evaluation / preemption check is notified from the PHY to the MAC" may mean that a notification indicating that the resource is unavailable or that reselection is required is transmitted from the PHY to the MAC in the UE. In other words, the notification may trigger the MAC layer to stop using the resource and perform reselection.

[0133] 2C) If the target resource for the re-evaluation / preemption check exists on multiple carriers, terminal 20 may perform the re-evaluation / preemption check on each carrier. For example, if the target resource exists on multiple carriers, resource #A and resource #B may be included in the target resource, and resource #A exists on carrier a and resource #B exists on carrier b.

[0134] If the resource subject to the reevaluation / preemption check exists on multiple carriers, for example, if a reevaluation / preemption check is notified from PHY to MAC for a certain resource of a certain carrier, terminal 20 may perform reselection without using the resource of that carrier.

[0135] If the resource subject to the reevaluation / preemption check exists on multiple carriers, for example, if a reevaluation / preemption check is notified from PHY to MAC for a certain resource on a certain carrier, terminal 20 may perform reselection without using the resource on all carriers (i.e., on any carrier).

[0136] By operating as described above, the reevaluation / preemption check can be performed in the same manner as in non-carrier aggregation, and the processing can be prevented from becoming complicated.

[0137] 2D) If the resource subject to the re-evaluation / preemption check exists on multiple carriers, the MAC layer may perform resource reselection from the resource pool containing the resource. This operation allows the reselection to be performed immediately from the resource for which resource identification has already been performed.

[0138] 2E) If the resource subject to the re-evaluation / preemption check is present on multiple carriers, the MAC layer may perform resource reselection on the same carrier as the resource subject to the re-evaluation / preemption check. This operation eliminates the need for re-selecting the carrier and simplifies the UE operation.

[0139] 2F) If the resource subject to the re-evaluation / preemption check exists on multiple carriers, the MAC layer may perform carrier selection again and reselect resources on the selected carrier. The carrier selection may be performed using any of the methods described in 1) above. This operation allows the best carrier to be selected when the re-evaluation / preemption check is performed, improving reliability.

[0140] FIG. 21 is a diagram illustrating an example (2) of carrier selection in an embodiment of the present invention. "Reselection 1" shown in FIG. 21 indicates carrier selection corresponding to the above 2D). That is, this is an example in which, when a target resource for reevaluation / preemption check exists on multiple carriers, the MAC layer performs resource reselection in a resource pool including the target resource. "Reselection 2" shown in FIG. 21 indicates carrier selection corresponding to the above 2E). That is, this is an example in which the MAC layer performs resource reselection on the same carrier as the target resource. "Reselection 3" shown in FIG. 21 indicates carrier selection corresponding to the above 2F). That is, this is an example in which the MAC layer performs carrier selection again and performs resource reselection on the selected carrier.

[0141] 2G) Based on predetermined conditions, the terminal 20 may switch between the above 2D), 2E), and 2F) to be applied. For example, based on the conditions shown in 1)-5) below, the terminal 20 may switch between the above 2D), 2E), and 2F) to be applied.

[0142] 1) Whether the resource subject to reevaluation / preemption check exists on multiple carriers or on a single carrier 2) Whether the RSRP threshold or CBR for the reevaluation / preemption check in the resource pool containing the resource subject to the reevaluation / preemption check exceeds a predetermined value 3) Whether the RSRP threshold or CBR for the re-evaluation / pre-emption check in the carrier that includes the resource subject to the re-evaluation / pre-emption check exceeds a predetermined value. 4) Whether a reassessment or preemption check was notified 5) Whether the resource to be reevaluated / preempted is already reserved (indicated by SCI)

[0143] By operating as described above, the terminal 20 can apply the optimal resource reselection method depending on the situation.

[0144] In the above embodiments, the carrier may be replaced with a CC (Component Carrier), a cell, a serving cell, a resource pool, or the like.

[0145] The above-described embodiment may be applied to an operation in which one terminal 20 configures or allocates transmission resources for another terminal 20.

[0146] The above-described embodiment is not limited to V2X terminals, and may be applied to terminals that perform D2D communication.

[0147] The operations according to the above-described embodiments 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 or Release 18 or later.

[0148] According to the above-described embodiment, in a sidelink where carrier aggregation is applied, the terminal 20 can perform carrier selection and resource re-evaluation / preemption check depending on the situation.

[0149] That is, in direct communication between terminals, communication by carrier aggregation can be performed.

[0150] (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.

[0151] <Base station 10> Fig. 22 is a diagram showing an example of the functional configuration of base station 10. As shown in Fig. 22, 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. 22 is merely an example. The functional divisions and names of the functional units may be any names as long as they can perform the operations related to the embodiments of the present invention.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] <Terminal 20> Fig. 23 is a diagram showing an example of the functional configuration of terminal 20. As shown in Fig. 23, 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. 23 is merely an example. The names of the functional divisions and functional units may be any names as long as they can execute the operations related to the embodiment of the present invention.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] (Hardware configuration) The block diagrams (FIGS. 22 and 23) 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 connected directly or indirectly (for example, by wire, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining the single device or the multiple devices with software.

[0160] 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.

[0161] 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. 24 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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. 22 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. 23 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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 outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0170] 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.

[0171] 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.

[0172] Fig. 25 shows an example configuration of a vehicle 2001. As shown in Fig. 25, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in the present disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example.

[0173] The drive unit 2002 is configured, for example, by an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle), and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0174] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2029 provided in the vehicle 2001. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0175] The signals from the various sensors 2021 to 2029 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0176] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing various types of information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information obtained from external devices via the communication module 2013, etc., to provide various types of multimedia information and multimedia services to the occupants of the vehicle 2001.

[0177] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as a millimeter-wave radar, a LiDAR (Light Detection and Ranging), a camera, a positioning locator (e.g., GNSS, etc.), map information (e.g., high-definition (HD) map, autonomous vehicle (AV) map, etc.), a gyro system (e.g., an IMU (Inertial Measurement Unit), an INS (Inertial Navigation System), etc.), an AI (Artificial Intelligence) chip, and an AI processor, as well as one or more ECUs that control these devices. The driving assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0178] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 29, which are provided in the vehicle 2001.

[0179] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0180] The communication module 2013 transmits, via wireless communication to an external device, a current signal from the current sensor that is input to the electronic control unit 2010. The communication module 2013 also transmits, via wireless communication to an external device, the rotation speed signals of the front and rear wheels acquired by a rotation speed sensor 2022, the air pressure signals of the front and rear wheels acquired by an air pressure sensor 2023, the vehicle speed signal acquired by a vehicle speed sensor 2024, the acceleration signal acquired by an acceleration sensor 2025, the accelerator pedal depression amount signal acquired by an accelerator pedal sensor 2029, the brake pedal depression amount signal acquired by a brake pedal sensor 2026, the shift lever operation signal acquired by a shift lever sensor 2027, and the detection signals for detecting obstacles, vehicles, pedestrians, etc. acquired by an object detection sensor 2028, which are input to the electronic control unit 2010.

[0181] The communication module 2013 receives various information (traffic information, traffic signal information, inter-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle 2001. The communication module 2013 also stores the various information received from the external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, sensors 2021 to 2029, etc. provided in the vehicle 2001.

[0182] (Summary of the embodiment) As described above, according to an embodiment of the present invention, a terminal is provided which has a communication unit that performs communication with another terminal to which carrier aggregation is applied, and a control unit that performs at least one of carrier selection related to the communication and reevaluation or preemption check related to the communication, wherein the control unit selects a carrier including a resource pool that satisfies certain conditions.

[0183] With the above configuration, in a side link to which carrier aggregation is applied, terminal 20 can perform carrier selection and resource reevaluation / preemption check according to the situation. That is, in direct terminal-to-terminal communication, communication by carrier aggregation can be performed.

[0184] The control unit may select a carrier including a resource pool in which the feedback channel is configured. With this configuration, in a side link to which carrier aggregation is applied, the terminal 20 can perform carrier selection according to the situation.

[0185] The control unit may select a carrier including a resource pool in which a certain permitted reservation period is set. With this configuration, in a sidelink to which carrier aggregation is applied, the terminal 20 can perform carrier selection according to the situation.

[0186] In the carrier selection that satisfies at least one of the following conditions 1) to 6), the control unit may apply at least one of the following conditions 1) to 6) in a certain order of priority. With this configuration, in a sidelink where carrier aggregation is applied, the terminal 20 can perform carrier selection according to the situation. 1) Capabilities of destination UE (User Equipment) for each carrier 2) Information related to sidelink HARQ feedback 3) Sensing and / or resource selection methods 4) Priority of transmitted data and carrier CBR 5) Periodic reservations 6) At least one of IUC (inter-UE coordination), RSRP (Reference Signal Received Power) threshold, and MCS (Modulation and Coding Scheme) table

[0187] In a reevaluation or preemption check when the target resource exists on multiple carriers, the control unit may perform any one of resource reselection in a resource pool including the target resource, resource reselection on the same carrier as the target resource, or resource reselection on the selected carrier after performing carrier selection again. With this configuration, in a sidelink where carrier aggregation is applied, the terminal 20 can perform resource reevaluation / preemption check depending on the situation.

[0188] Furthermore, according to an embodiment of the present invention, there is provided a communication method in which a terminal executes a communication procedure for executing communication with another terminal to which carrier aggregation is applied, a control procedure for executing at least one of carrier selection related to the communication and a reevaluation or preemption check related to the communication, and a procedure for selecting a carrier including a resource pool that satisfies certain conditions.

[0189] With the above configuration, in a side link to which carrier aggregation is applied, terminal 20 can perform carrier selection and resource reevaluation / preemption check according to the situation. That is, in direct terminal-to-terminal communication, communication by carrier aggregation can be performed.

[0190] (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.

[0191] 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.

[0192] Each aspect / embodiment described in the present disclosure may be any of the following: LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or decimal number)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE The present invention may be applied to at least one of systems using 802.20, UWB (Ultra-Wideband), Bluetooth (registered trademark), or other appropriate systems, and next-generation systems that are extended, modified, created, or defined based on these systems. The present invention may also be applied to a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G).

[0193] 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.

[0194] 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).

[0195] 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.

[0196] 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.

[0197] 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).

[0198] 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.

[0199] 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.

[0200] 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.

[0201] 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.

[0202] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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.

[0214] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0215] 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."

[0216] 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.

[0217] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0218] 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.

[0219] 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.

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] 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.

[0231] 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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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."

[0237] 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.

[0238] 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.

[0239] 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."

[0240] 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).

[0241] 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.

[0242] <Additional Notes> (Additional note 1) a communication unit that performs communication with another terminal using carrier aggregation; a control unit that performs at least one of a carrier selection related to the communication and a re-evaluation or preemption check related to the communication; The control unit is a terminal that selects a carrier that includes a resource pool that satisfies a certain condition. (Additional note 2) 2. The terminal according to claim 1, wherein the control unit selects a carrier including a resource pool in which a feedback channel is set. (Additional note 3) The terminal according to claim 1, wherein the control unit selects a carrier including a resource pool in which a certain permitted reservation period is set. (Additional note 4) The terminal according to claim 1, wherein the control unit applies at least one of the following 1) to 6) in a certain order of priority when selecting a carrier that satisfies at least one of the following conditions 1) to 6): 1) Capabilities of destination UE (User Equipment) for each carrier 2) Information related to sidelink HARQ feedback 3) Sensing and / or resource selection methods 4) Priority of transmitted data and carrier CBR 5) Periodic reservations 6) At least one of IUC (inter-UE coordination), RSRP (Reference Signal Received Power) threshold, and MCS (Modulation and Coding Scheme) table (Additional note 5) The terminal according to appended claim 1, wherein the control unit, in a reevaluation or preemption check when the target resource exists on multiple carriers, performs one of the following: resource reselection in a resource pool that includes the target resource; resource reselection on the same carrier as the target resource; or carrier selection is performed again and resource reselection on the selected carrier. (Additional note 6) A communication procedure for performing communication with another terminal using carrier aggregation; a control procedure for performing at least one of a carrier selection for the communication and a re-evaluation or pre-emption check for the communication; A communication method in which a terminal executes a procedure for selecting a carrier that includes a resource pool that satisfies certain conditions. [Explanation of symbols]

[0243] 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 2001 Vehicle 2002 Drive unit 2003 Steering Section 2004 accelerator pedal 2005 brake pedal 2006 Shift Lever 2007 front wheel 2008 rear wheel 2009 Axle 2010 Electronic Control Unit 2012 Information Services Department 2013 Communication Module 2021 Current Sensor 2022 RPM Sensor 2023 Air Pressure Sensor 2024 Vehicle speed sensor 2025 Acceleration Sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object Detection Sensor 2029 Accelerator pedal sensor 2030 Driving Assistance Systems Department 2031 microprocessor 2032 memory (ROM, RAM) 2033 Communication port (IO port)

Claims

1. a control unit that, when selecting a carrier for transmitting sidelink data, selects a target carrier and a resource pool associated with the target carrier based on a Channel Busy Ratio (CBR) of the target carrier and a priority of a sidelink logical channel; a transmitter configured to perform sidelink communication transmission via the selected plurality of carriers in the same time unit; A terminal comprising:

2. The control unit selects the target carrier and a resource pool associated with the target carrier when a CBR of the target carrier is lower than a threshold associated with a priority of the sidelink logical channel. The terminal according to claim 1 .

3. When selecting a carrier for transmitting data requiring feedback, the control unit selects a resource pool in which a resource for a feedback channel is configured. The terminal according to claim 1 .

4. The control unit selects a resource pool in which a resource pool of a feedback channel is set when an information element sl-HARQ-FeedbackEnabled is set to enabled for the logical channel corresponding to the data. The terminal according to claim 1 .

5. selecting a target carrier and a resource pool associated with the target carrier based on a Channel Busy Ratio (CBR) of the target carrier and a priority of a sidelink logical channel when selecting a carrier for transmitting sidelink data; transmitting sidelink communication over the selected plurality of carriers in the same time unit; A communication method by a terminal, comprising:

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