Terminal and Communication Method

Abstract

This terminal includes: a reception unit that receives, from one or more other terminals respectively, one or more reservation information items pertaining to the same resource; a control unit that determines whether a specific condition has been satisfied; and a transmission unit that transmits information pertaining to the same resource to any of the other terminals, in a case where the control unit has determined that the specific condition has been satisfied.

Description

Technical Field

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

Background Art

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

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

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

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] As an enhancement of the NR side link, power saving is being considered. For example, in Resource Allocation Mode 2 where the terminal autonomously selects resources, the terminal performs partial sensing on limited resources within the sensing window and selects available resource candidates from the resource selection window based on the results.

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

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

MEANS FOR SOLVING THE PROBLEMS

[0009] According to the disclosed technology, A first terminal, comprising: a receiving unit configured to receive, from a second terminal, first reservation information for reserving a first resource and receive, from a third terminal, second reservation information for reserving a second resource; a control unit configured to determine whether a specific condition based on a first time from reception of the first reservation information or the second reservation information to a resource for transmitting information regarding a collision between the first resource and the second resource and a second time from the resource for transmitting the information regarding the collision to a resource where the collision may occur is satisfied; and a transmitting unit configured to transmit the information regarding the collision when the control unit determines that the specific condition is satisfied is provided.

EFFECTS OF THE INVENTION

[0010] According to the disclosed technology, in direct communication between terminals, the reliability of communication during autonomous resource selection can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]

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Embodiments for Carrying Out the Invention

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

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

[0014] Also, in the embodiment of the present invention, the duplex mode may be a TDD (Time Division Duplex) mode, an FDD (Frequency Division Duplex) mode, or other modes (e.g., Flexible Duplex, etc.).

[0015] Also, in the embodiment of the present invention, the fact that wireless parameters or the like are "configured" may mean that predetermined values are pre-configured, or may mean that wireless parameters notified from the base station 10 or the terminal 20 are configured.

[0016] FIG. 1 is a diagram for explaining V2X. In 3GPP, it is being studied to realize V2X (Vehicle to Everything) or eV2X (enhanced V2X) by expanding the D2D function, and standardization is in progress. As shown in FIG. 1, V2X is a part of ITS (Intelligent Transport Systems), and means V2V (Vehicle to Vehicle), which is a communication form carried out between vehicles, V2I (Vehicle to Infrastructure), which is a communication form carried out between a vehicle and a roadside unit (RSU) installed on the roadside, V2N (Vehicle to Network), which is a communication form carried out between a vehicle and an ITS server, and V2P (Vehicle to Pedestrian), which is a communication form carried out between a vehicle and a mobile terminal held by a pedestrian.

[0017] In addition, in 3GPP, V2X using LTE or NR cellular communication and device-to-device communication is being studied. V2X using cellular communication is also referred to as cellular V2X. In NR V2X, studies are underway to achieve large capacity, low latency, high reliability, and QoS (Quality of Service) control.

[0018] Regarding LTE or NR V2X, it is assumed that studies will be carried out in the future not limited to 3GPP specifications. For example, ensuring interoperability, reducing costs through upper layer implementation, methods of using or switching between multiple RATs (Radio Access Technologies), regulatory compliance in each country, data acquisition, distribution, database management, and utilization methods of LTE or NR V2X platforms are assumed to be studied.

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

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

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

[0022] In the SL of LTE, Mode3 and Mode4 are defined for the resource allocation of SL to the terminal 20. In Mode3, the transmission resources are dynamically allocated by DCI (Downlink Control Information) transmitted from the base station 10 to the terminal 20. Also, SPS (Semi Persistent Scheduling) is possible in Mode3. In Mode4, the terminal 20 autonomously selects the transmission resources from the resource pool.

[0023] Note that the slot in the embodiment of the present invention may be read as a symbol, a mini - slot, a sub - frame, a radio frame, a TTI (Transmission Time Interval). Also, the cell in the embodiment of the present invention may be read as a cell group, a carrier component, a BWP, a resource pool, a resource, a RAT (Radio Access Technology), a system (including wireless LAN), etc.

[0024] Note that 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 owned by a user such as a smartphone, or an IoT (Internet of Things) device such as a smart meter.

[0025] FIG. 2 is a diagram for explaining an example (1) of the transmission mode of V2X. In the transmission mode of sidelink communication shown in FIG. 2, in step 1, the base station 10 transmits sidelink scheduling to the terminal 20A. Subsequently, the terminal 20A transmits the PSCCH (Physical Sidelink Control Channel) and PSSCH (Physical Sidelink Shared Channel) to the terminal 20B based on the received scheduling (step 2). The transmission mode of sidelink communication shown in FIG. 2 may be 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 the UTRAN (Universal Terrestrial Radio Access Network) and the UE (User Equipment). Note that the transmission mode of sidelink communication shown in FIG. 2 may be referred to as sidelink transmission mode 1 in NR.

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

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

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

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

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

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

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

[0033] Also, in NR-V2X, it is assumed that HARQ (Hybrid automatic repeat request) is supported for sidelink unicast and groupcast. Furthermore, in NR-V2X, SFCI (Sidelink Feedback Control Information) including HARQ responses is defined. Furthermore, it is being considered that the SFCI is transmitted via the PSFCH (Physical Sidelink Feedback Channel).

[0034] Note that in the following description, the PSFCH is used for transmitting HARQ-ACK in the sidelink, but this is just an example. For example, the PSCCH may be used to transmit HARQ-ACK in the sidelink, the PSSCH may be used to transmit HARQ-ACK in the sidelink, or other channels may be used to transmit HARQ-ACK in the sidelink.

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

[0036] FIG. 10 is a sequence diagram showing an operation example (1) of V2X. As shown in FIG. 10, the wireless communication system according to the embodiment of the present invention may include a terminal 20A and a terminal 20B. In practice, there are a large number of user devices, but FIG. 10 shows the terminal 20A and the terminal 20B as an example.

[0037] Hereinafter, when the terminal 20A, 20B, etc. are not particularly distinguished, they are simply described as "terminal 20" or "user device". In FIG. 10, as an example, the case where both the terminal 20A and the terminal 20B are within the coverage of the cell is shown, but the operation in the embodiment of the present invention can also be applied when the terminal 20B is outside the coverage.

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

[0039] Note that the terminal 20 does not necessarily need to be a device in one housing. For example, even when various sensors are distributed and arranged in a vehicle, the device including the various sensors may be the terminal 20.

[0040] Also, the processing content of the sidelink transmission data of the terminal 20 is basically the same as the processing content of UL transmission in LTE or NR. For example, the terminal 20 scrambles the codewords of the transmission data, modulates them to generate complex-valued symbols, maps the complex-valued symbols (transmission signals) to 1 or 2 layers, and performs precoding. Then, the precoded complex-valued symbols are mapped to resource elements to generate a transmission signal (e.g., complex-valued time-domain SC-FDMA signal), which is transmitted from each antenna port.

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

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

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

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

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

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

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

[0048] Note that if HARQ control with HARQ feedback is not executed, steps S104 and S105 may not be executed.

[0049] FIG. 11 is a sequence diagram showing an operation example (2) of V2X. Blind retransmission not depending on HARQ control for improving the transmission success rate or the reach distance may be executed.

[0050] In step S201, the 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 from the base station 10 to the terminal 20.

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

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

[0053] Note that if blind retransmission is not executed, step S204 may not be executed.

[0054] FIG. 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. Further, when HARQ control involving HARQ feedback is applied, the base station 10 may transmit information indicating the resources of the PSFCH to the terminal 20.

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

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

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

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

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

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

[0061] In step S305, the terminal 20A transmits a HARQ-ACK at a timing (e.g., a timing in units of slots) specified by, for example, DL scheduling DCI (or SL scheduling DCI) by using the 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 of the HARQ-ACK may include a HARQ-ACK generated based on the HARQ-ACK received from the terminal 20B or the PSFCH not received, and a HARQ-ACK for DL data. However, when there is no allocation of DL data, etc., the HARQ-ACK for DL data is not included. In NR Rel.16, the HARQ-ACK codebook does not include the HARQ-ACK for DL data.

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

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

[0064] In FIG. 13, the vertical axis corresponds to the frequency domain and the horizontal axis corresponds to the time domain. The PSCCH may be arranged in 1 symbol at the beginning of a slot, or in a plurality of symbols from the beginning, or in a plurality of symbols from symbols other than the beginning. The PSFCH may be arranged in 1 symbol at the end of a slot, or in a plurality of symbols at the end of a slot. Note that the above-mentioned "beginning of a slot" and "end of a slot" may omit consideration of symbols for Automatic Gain Control (AGC) and symbols for transmission / reception switching. That is, for example, when 1 slot is composed of 14 symbols, the "beginning of a slot" and "end of a slot" may mean the first and last symbols among the 12 symbols excluding the first and last symbols. In the example shown in FIG. 13, three subchannels are set in a resource pool, and two PSFCHs are arranged 3 slots after the slot in which the PSSCH is arranged. The arrow from the PSSCH to the PSFCH indicates an example of the PSFCH associated with the PSSCH.

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

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

[0067] Also, as shown in FIG. 14, the setting of the resource pool may have a period. For example, the period may be a period of 10,240 milliseconds. FIG. 14 shows slot t0 SLfrom slot t Tmax SL This is an example where the range from... to slot t is set as a resource pool. The resource pool within each period may have its area set by, for example, a bitmap.

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

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

[0070] The resource selection window from slot n + T1 to slot n + T2, as shown in FIG. 14, identifies the resources occupied by other UEs, and the resources from which such occupied resources are excluded become candidate available resources. Let the set of candidate available resources be S A ; then S AIf it is less than 20% of the resource selection window, the threshold Th set for each resource in the sensing window pTX,pRX may be increased by 3 dB and the resource identification may be performed again. That is, the threshold Th pTX,pRX By increasing and performing the resource identification again, resources that are not excluded because the RSRP is less than the threshold are increased, and the set S A of resource candidates may be made to be 20% or more of the resource selection window. S A If it is less than 20% of the resource selection window, the threshold Th set for each resource in the sensing window pTX,pRX The operation of increasing by 3 dB and performing the resource identification again may be repeated.

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

[0072] In FIG. 14 described above, the operation of the transmitting terminal 20 was described. However, the receiving terminal 20 may detect data transmission from another terminal 20 based on the result of sensing or partial sensing, and receive data from the other terminal 20.

[0073] FIG. 15 is a flowchart showing an example of preemption in NR. FIG. 16 is a diagram showing an example of preemption in NR. In step S501, the terminal 20 performs sensing in the sensing window. When the terminal 20 performs power saving operation, sensing may be performed in a predefined limited period. Subsequently, the terminal 20 identifies each resource in the resource selection window based on the sensing result and determines the set S A of resource candidates (S502). Subsequently, the terminal 20 selects a resource set (r_0, r_1, ···) from the set S A of resource candidates (S503).

[0074] In step S504, at the timing of T(r_0)-T3 shown in FIG. 16, the terminal 20 re-identifies each resource within the resource selection window based on the sensing result to determine a set S A of resource candidates, and further determines preemption based on the priority. For example, for r_1 shown in FIG. 16, an SCI transmitted from another terminal 20 has been detected by the re-sensing and is not included in S A . When preemption is valid, 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 own terminal, the terminal 20 determines that the resource r_1 has been preempted. Note that a lower value indicates a higher priority. That is, when the value prio_RX indicating the priority of the SCI transmitted from another terminal 20 is higher than the value prio_TX indicating the priority of the transport block transmitted from the own terminal, the terminal 20 does not exclude the resource r_1 from S A . Or, when preemption is only valid for a specific priority (for example, sl-PreemptionEnable is any one of pl1, pl2, ..., pl8), this priority is set as prio_pre. At this time, if the value prio_RX indicating the priority of the SCI transmitted from another 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 own terminal, the terminal 20 determines that the resource r_1 has been preempted.

[0075] In step S505, when preemption is determined in step S504, the terminal 20 notifies the upper layer of the preemption, the upper layer re-selects the resource, and the process related to the preemption ends.

[0076] In the NR Release 17 side link, power saving based on the above-mentioned random resource selection and partial sensing is being considered. For example, for power saving, the random resource selection and partial sensing of the side link in LTE Release 14 may be applied to Resource Allocation Mode 2 of the NR Release 16 side link. The terminal 20 to which partial sensing is applied performs reception and sensing only in specific slots within the sensing window.

[0077] Also, in the NR Release 17 side link, enhanced Ultra Reliable Low Latency Communication (eURLLC) is being considered with inter-UE coordination as the baseline. For example, terminal 20A may share information indicating a resource set with terminal 20B, and terminal 20B may consider this information in resource selection for transmission.

[0078] In Resource Allocation Mode 2 where terminal 20 autonomously selects resources, the resource reservation information of other terminals 20 is received by sensing, and based on this resource reservation information, terminal 20 selects the resources to be used for transmission. However, even when each transmitting terminal 20 selects resources based on sensing, resource collisions can occur.

[0079] FIG. 17 is a diagram showing an example (1) of a communication situation. As an example of the hidden terminal problem, as shown in FIG. 17, when trying to transmit from terminal 20A to terminal 20B, there may be a terminal 20C that cannot be detected from terminal 20A and is located at a position where it interferes with the receiving terminal 20B. For example, if terminal 20C transmits at the time resource reserved by terminal 20A, a resource overlap occurs when terminal 20B receives.

[0080] Also, since the side link is half-duplex communication, there is a possibility of resource collisions when both terminals 20 transmit.

[0081] FIG. 18 is a diagram showing an example (2) of a communication situation. As an example of the near-far problem, when attempting to transmit from terminal 20C to terminal 20B, as shown in FIG. 18, there may be a case where terminal 20A, which is detected with a small power at the transmitting terminal 20C, exists at a position where it causes a large interference to the receiving terminal 20B.

[0082] Each terminal 20 can reserve future transmission resources. FIG. 19 is a diagram showing an example (3) of a communication situation. As shown in FIG. 19, a resource collision can occur between the resources designated as reservations from terminal 20A and terminal 20C. That is, terminal 20B, which has received a plurality of reservation information, can know in advance the resource collision that will occur in the future. On the other hand, even if it was possible to detect a future resource collision in the prior art, it was difficult to avoid such a collision.

[0083] Therefore, when terminal 20 has received one or more pieces of reservation information related to the same resource, if a specific condition is satisfied, it may transmit specific information to a specific terminal 20 in a specific method.

[0084] FIG. 20 is a flowchart for explaining a communication method according to an embodiment of the present invention. In step S601, terminal 20 receives one or more pieces of reservation information related to the same resource. In the subsequent step S602, terminal 20 determines whether a specific condition is satisfied. If the specific condition is satisfied (YES in S602), it proceeds to step S603, and if the specific condition is not satisfied (NO in S602), the flow ends. In step S603, terminal 20 transmits specific information to a specific terminal 20 in a specific method.

[0085] By executing the above flowchart, it is possible to avoid a resource collision, and the reliability and delay are improved. Details of each subsequent step will be described below. Hereinafter, terminal 20 that has received reservation information is referred to as terminal 20B, and terminal 20 that has transmitted reservation information is referred to as terminal 20A or terminal 20C, etc.

[0086] The "one or more reservation information related to the same resource" in step S601 shown in FIG. 20 may be any of the following 1) to 6).

[0087] 1) A plurality of reservation signals, which are information for reserving PSCCH / PSSCH resources with the same time resource. For example, the reservation information is the reservation information shown in FIG. 21, which is transmitted by terminal 20A and terminal 20C and received by terminal 20B.

[0088] 2) A plurality of reservation signals, which are information for reserving PSCCH / PSSCH resources with the same time resource and at least a part of the frequency resources being the same. For example, the reservation information is the reservation information shown in FIG. 22, which is transmitted by terminal 20A and terminal 20C and received by terminal 20B.

[0089] 3) A plurality of reservation signals, which are information for reserving PSCCH / PSSCH resources corresponding to the same PSFCH opportunity with the same time resource. For example, the reservation information is the reservation information shown in FIG. 23, which is transmitted by terminal 20A and terminal 20C and received by terminal 20B.

[0090] 4) One or more reservation signals, which are information for reserving PSCCH / PSSCH resources with the same time resource as the resources (selected or reserved) that terminal 20B plans to transmit. For example, the reservation information is the reservation information shown in FIG. 24, which is received by terminal 20B from terminal 20A.

[0091] 5) One or more reservation signals, which are information for reserving PSCCH / PSSCH resources with the same time resource as the resources (selected or reserved) that terminal 20B plans to transmit and at least a part of the frequency resources being the same. For example, the reservation information is the reservation information shown in FIG. 25, which is received by terminal 20B from terminal 20A.

[0092] 6) A reservation signal of 1 or more, information for reserving a PSFCH resource that the terminal 20B plans to transmit or receive, and a PSCCH / PSSCH resource corresponding to a PSFCH opportunity with the same time resource. For example, the reservation information is the reservation information shown in FIG. 26 that the terminal 20A transmits and the terminal 20B receives.

[0093] Note that the "one or more reservation information related to the same resource" in step S601 shown in FIG. 20 may be a periodic reservation (for example, a reservation by a resource reservation period field) or an aperiodic reservation (for example, a reservation by a time resource assignment field). By the above 1)-6), it is expected that communication failures caused by at least one of the hidden terminal problem, half-duplex communication, and near-far problem can be avoided by the method described later.

[0094] The "specific conditions" in step S602 shown in FIG. 20 may be at least one of the conditions shown in the following 1)-12).

[0095] 1) When the reception power of the received reservation information satisfies a predetermined condition, for example, the following a) or b). Based on the interference situation, the necessity of applying the method described later can be determined. a) At least one reception power P of the received reservation information satisfies being greater than X (or X or more) or less than X (or X or less). X may be given by a higher layer parameter or may be associated with the priority. b) The difference P_dif between any two pieces of received reservation information satisfies being greater than Y (or Y or more) or less than Y (or Y or less). Y may be given by a higher layer parameter or may be associated with the priority.

[0096] 2) When the priority of the received reservation information and / or the priority related to the transmission or reception of terminal 20B satisfies a predetermined condition (for example, a predetermined relationship). For example, when two pieces of reservation information are received and the priority of either one is higher than that of the other. Also, for example, when two pieces of reservation information are received, if the received RSRP of the reservation information with a higher priority is smaller than or smaller by Z dB or more than that of the other. Z may be given by a higher layer parameter or may be associated with the priority. Note that the priority may be the priority at the PHY layer or the priority at the MAC layer. Based on the priority, the necessity of applying the method described below can be determined.

[0097] 3) When the HARQ feedback corresponding to the transmission including reservation information satisfies a predetermined condition. For example, when at least two PSFCH transmissions are NACK transmissions. Furthermore, it may be added as a condition that all transmissions including reservation information are unicast transmissions. Based on whether the reservation resource is used or not, the necessity of applying the method described below can be determined.

[0098] 4) When a specific time constraint is satisfied. For example, when the time from the reception of the reservation information to the reserved resource is equal to or more than a predetermined value. Also, for example, when the time from the reception of the reservation information to the transmission of the specific information in step S603 shown in FIG. 20 is equal to or more than a predetermined value. Also, for example, when the time from the transmission of the specific information in step S603 shown in FIG. 20 to the reserved resource is equal to or more than a predetermined value. Note that the predetermined value may be given by a higher layer parameter, may be defined as the number of symbols or slots, and different values may be set depending on the SCS (Sub-carrier spacing) or numerology. Based on whether there is a time when the method described below can be applied, the necessity of applying the method described below can be determined.

[0099] 5) When the destination related to the reservation information meets a predetermined condition. For example, when at least one destination includes the terminal 20B. Also, for example, when all destinations include the terminal 20B. Based on whether one should apply the method described below, the necessity of applying the method described below can be determined.

[0100] 6) When the location information related to the reservation information meets a predetermined condition. For example, when the distance between a plurality of terminals 20 that transmitted the reservation information is greater than or equal to or less than a predetermined value. Also, for example, when the distance between the terminal 20 that transmitted the reservation information and the terminal 20B that received the reservation information is greater than or equal to or less than a predetermined value. Based on the interference situation, the necessity of applying the method described below can be determined.

[0101] 7) When the terminal 20 that transmitted the reservation information is a terminal 20 equipped with a specific function. For example, when the terminal 20B receives a specific instruction in a bit field (for example, a field included in SCI) that can only be understood by terminals 20 after Release 17. For example, when the terminal 20B receives a notification supported in specific UE capability signaling. Based on whether the communication partner is capable of applying the method described below, the necessity of applying the method described below can be determined.

[0102] 8) When the transmission resource of the reservation information meets a predetermined condition. For example, when at least one transmission of the reservation information is transmitted using a self-organized resource selection (for example, mode 2). Also, for example, when all transmissions of the reservation information are transmitted using a self-organized resource selection (for example, mode 2). Also, whether the resource is set or instructed by the network (for example, mode 1) or is a resource selected by self-organized resource selection (for example, mode 2) may be notified to the terminal 20B in relation to the transmission of the reservation information. For example, it may be notified to the terminal 20B by SCI (1st stage SCI, 2nd stage SCI, PSCCH or PSSCH) or DCI. Based on whether self-organized resource change is possible, the necessity of applying the method described below can be determined.

[0103] 9) When the cast type related to the reservation information satisfies a predetermined condition. For example, when at least one cast type is a specific cast type. Also, for example, when all cast types are a specific cast type. Based on the cast type, for example, based on whether the cast type is such that the method described later can be applied, the necessity of applying the method described later can be determined.

[0104] 10) When the number of reserved resources related to the reservation information satisfies a predetermined condition. For example, when at least one reservation information reserves 2 or more resources. Also, for example, when all reservation information reserves 2 or more resources. Based on whether there are resources that do not cause problems reserved together, the necessity of applying the method described later can be determined.

[0105] 11) When the packet maximum delay (Packet delay budget, PDB) related to the reservation information satisfies a predetermined condition. For example, when the PDB or the remaining time until the PDB related to at least one reservation information is equal to or greater than a predetermined size. Also, for example, when the PDB or the remaining time until the PDB related to all reservation information is equal to or greater than a predetermined size. Based on whether the transmission delay is allowed, the necessity of applying the method described later can be determined.

[0106] 12) When requested to transmit specific information in step S603 shown in FIG. 20 from another terminal 20.

[0107] The "specific terminal 20" in step S603 shown in FIG. 20 may be at least one of the terminals 20 shown in 1)-12) below.

[0108] 1) The terminal 20 that transmitted the reservation information whose received power of the reservation information satisfies a predetermined condition, for example, a) or b) below. Based on the interference situation, the terminal to which the method described later should be applied can be determined. a) The received power P of at least one of the received reservation information satisfies that P is greater than X (or may be X or more) or less than X (or may be X or less). X may be given by a higher layer parameter, or X may be associated with a priority. b) The difference P_dif between any two received reservation information satisfies that P_dif is greater than Y (or may be Y or more) or less than Y (or may be Y or less). Y may be given by a higher layer parameter, or Y may be associated with a priority.

[0109] 2) The terminal 20 whose priority related to the reservation information satisfies a predetermined condition. For example, the terminal 20 whose priority related to the reservation information is lower than a predetermined value. Note that the priority may be the priority in the PHY layer or the priority in the MAC layer. Based on the priority, the terminal to which the method described later should be applied can be determined.

[0110] 3) The terminal 20 whose HARQ feedback corresponding to the transmission including the reservation information satisfies a predetermined condition. For example, the terminal 20 whose corresponding HARQ feedback is a NACK transmission. The terminal using the reservation resource can be determined as the terminal to which the method described later should be applied.

[0111] 4) The terminal 20 that meets specific time constraints. For example, the terminal 20 that transmits reservation information where the time from receiving the reservation information to the reserved resource is equal to or greater than a predetermined value. Also, for example, the terminal 20 that transmits reservation information where the time from receiving the reservation information to transmitting specific information in step S603 shown in FIG. 20 is equal to or greater than a predetermined value. Also, for example, the terminal 20 that transmits reservation information where the time from transmitting the specific information in step S603 shown in FIG. 20 to the reserved resource is equal to or greater than a predetermined value. Note that the predetermined value may be given by a higher layer parameter, may be defined as the number of symbols or slots, and different values may be set depending on the SCS or numerology. Also, for example, the terminal 20 that transmits reservation information where the reception of the reservation information is the earliest or latest in the time domain. Also, for example, the terminal 20 that transmits reservation information where the time of transmitting the specific information in step S603 shown in FIG. 20 is the earliest or latest in the time domain. Also, for example, the terminal 20 that transmits reservation information where the time of the reserved resource is the earliest or latest in the time domain. Based on the processing time and delay performance, a terminal suitable for applying the method described later can be determined.

[0112] 5) The terminal 20 where the destination related to the reservation information meets predetermined conditions. For example, the terminal 20 that transmits reservation information where at least one destination of the reservation information is unicast, groupcast, or broadcast including terminal 20B. Also, for example, the terminal 20 that transmits reservation information where the destination of the reservation information is unicast only to terminal 20B. Also, for example, the terminal 20 that transmits reservation information where the destination of the reservation information does not include terminal 20B and has a lower priority than other reservation information. Based on the communication partner, a terminal suitable for applying the method described later can be determined.

[0113] 6) The terminal 20 where the location information related to the reservation information meets predetermined conditions. For example, the terminal 20 that transmits reservation information where the distance from terminal 20B is the maximum or minimum. Also, for example, the terminal 20 that transmits reservation information where the distance from terminal 20B is equal to or greater than or equal to or less than a predetermined value. Based on the interference situation, a terminal to which the method described later should be applied can be determined.

[0114] 7) When the terminal 20 that transmitted the reservation information is a terminal 20 having a specific function. For example, a terminal 20 capable of performing inter-terminal cooperative operations. A terminal to which the following method can be applied can be determined as a terminal to which the following method should be applied.

[0115] 8) A terminal 20 where the transmission resource of the reservation information satisfies a predetermined condition. For example, a terminal 20 that transmits the reservation information using a resource by autonomous resource selection (e.g., mode 2). Also, whether the resource is set or instructed by the network (e.g., mode 1) or a resource by autonomous resource selection (e.g., mode 2) may be notified to the terminal 20B in relation to the transmission of the reservation information. For example, it may be notified to the terminal 20B by SCI (1st stage SCI, 2nd stage SCI, PSCCH, or PSSCH) or DCI. A terminal capable of autonomous resource change can be determined as a terminal to which the following method should be applied.

[0116] 9) A terminal 20 where the cast type related to the reservation information satisfies a predetermined condition. For example, a terminal 20 that transmits the reservation information using a specific cast type. For example, a terminal that performs communication using a cast type to which the following method can be applied can be determined as a terminal to which the following method should be applied.

[0117] 10) A terminal 20 where the number of reservation resources related to the reservation information satisfies a predetermined condition. For example, a terminal 20 that transmitted reservation information reserving two or more resources. A terminal that has reserved resources where no problem occurs can be determined as a terminal to which the following method should be applied.

[0118] 11) A terminal 20 where the packet maximum delay (Packet delay budget, PDB) related to the reservation information satisfies a predetermined condition. For example, a terminal 20 where the PDB related to the reservation information or the remaining time until the PDB is equal to or greater than a predetermined size. A terminal where transmission delay is tolerated can be determined as a terminal to which the following method should be applied.

[0119] 20. The terminal 20 that requested the terminal 20B to transmit the specific information in step S603 shown in FIG. 20.

[0120] The "specific information" in step S603 shown in FIG. 20 may be at least one of the information shown in the following 1)-6). The terminal 20 that has received the "specific information" can know that it should perform an operation to avoid a collision.

[0121] 1) Information indicating that a fact of a collision has been detected.

[0122] 2) Information indicating that a change in resources is recommended or requested. Note that "recommended" means that the terminal 20 that has received the information follows it as much as possible, and in some cases, it does not have to follow it, and "requested" means that the terminal 20 that has received the information must follow it.

[0123] 3) Information indicating that it is recommended or requested not to use resources.

[0124] 4) Recommending or requesting a change in transmission power. The difference in transmission power from the signal related to the reservation may be notified, or the absolute value of the transmission power may be notified.

[0125] 5) Information indicating the target resources. For example, a slot index and / or an offset may be notified, or which resource it is when the reservation is periodic may be notified.

[0126] 6) Information indicating the value or range of the priority to be transmitted with the resource. For example, it may be notified that only transmissions with a value of the priority being X or less are possible. This information may be transmitted by broadcast.

[0127] The "specific method" in step S603 shown in FIG. 20 may be at least one of the methods shown in the following 1)-3). The method of transmitting the specific information can be clarified.

[0128] 1) Information specific to step S603 shown in FIG. 20 may be transmitted by a resource or a transmission method related to the feedback channel. The resource or the transmission method related to the feedback channel may be a resource or a transmission method shown in a)-l) below.

[0129] a) Resources available for PSFCH. For example, the time resource may be the X-th (e.g., the second) symbol from the last in a slot for each parameter sl-PSFCH-Period indicating the period of PSFCH. Also, for example, the frequency resource may be a PRB determined based on a parameter sl-PSFCH-RB-Set indicating the frequency region of PSFCH. Also, the code resource may be a pair of cyclic shifts determined based on a parameter sl-NumMuxCS-Pair related to the cyclic shift of PSFCH. Note that the PSFCH resource determination formula in Release 16 {(P ID +M ID ) mod R PSFCH PRB,CS} may be different from the method of determining the PSFCH resource. Note that P ID is the source ID of the PHY layer, MID is the ID of the UE, and R PSFCH PRB,CS is the number of PSFCH resources for transmitting (multiplexing) HARQ-ACK in one PSFCH transmission opportunity.

[0130] b) Resources available for PSFCH and resources frequency-division multiplexed and / or code-division multiplexed. FIG. 27 is a diagram showing an example (1) of resources used for communication in an embodiment of the present invention. For example, it may be at least a part of the PRBs other than the PRBs specified by sl-PSFCH-RB-Set in a certain resource pool. That is, in FIG. 27, the PRBs in which the PSFCH associated with the PSSCH is arranged and the PRBs frequency-division multiplexed therewith may be used as resources related to the feedback channel. Also, the PRBs specified by sl-PSFCH-RB-Set in a certain resource pool may be used as resources related to the feedback channel. FIG. 28 is a diagram showing an example (2) of resources used for communication in an embodiment of the present invention. For example, the cyclic shift pairs determined based on the sl-NumMuxCS-Pair defined as shown in FIG. 28 may be used as resources related to the feedback channel, or all the cyclic shift pairs may be used as resources related to the feedback channel, or the cyclic shift pairs determined based on a certain parameter may be used as resources related to the feedback channel.

[0131] FIG. 29 is a diagram showing an example (3) of resources used for communication in an embodiment of the present invention. As shown in FIG. 29, the PSFCH resources determined by the PSFCH resource determination formula in Release 16 (for example, the resources used for NACK transmission) and the resources associated one-to-one therewith may be used as resources related to the feedback channel.

[0132] At least a part of the cyclic shift pairs other than the cyclic shift pairs determined based on the sl-NumMuxCS-Pair, which are the PRBs specified by sl-PSFCH-RB-Set, may be used as resources related to the feedback channel. In the example shown in FIG. 28, when Y = 2, that is, when the cyclic shifts are 0 and 3 for NACK and 6 and 9 for ACK, the cyclic shifts {1, 2, 4, 5, 7, 8, 10, 11} not used for HARQ-ACK may be used as resources related to the feedback channel.

[0133] FIG. 30 is a diagram showing an example (4) of resources used for communication in an embodiment of the present invention. As shown in FIG. 30, an index adjacent to the CS index used for NACK transmission may be used as a resource related to the feedback channel. FIG. 20 shows an example in which the CS index used for NACK transmission is {0, 3}, and the CS index {1, 4} is used as a resource related to the feedback channel.

[0134] c) Resources not based on the source ID.

[0135] d) Resources determined based on the source ID or a part of the source ID included in the 1st stage SCI.

[0136] e) It may be transmitted as an alternative to the HARQ feedback of Release 16. For example, NACK or specific information may be transmitted in the resources determined by a) or b) above. Also, nothing may be transmitted in the resources determined by the PSFCH resource determination formula in Release 16 above.

[0137] f) It may be transmitted together with the HARQ feedback of Release 16. For example, NACK or specific information may be transmitted in the resources determined by a) or b) above. Also, it may be transmitted in the resources determined by the PSFCH resource determination formula in Release 16 above.

[0138] g) The transmission in 1) above may be treated as a PSFCH transmission. For example, the operation of the terminal 20 related to the simultaneous transmission of the PSFCH may be processed including the transmission in 1) above.

[0139] h) The transmission in 1) above may not be treated as a PSFCH transmission. For example, it may be defined as a channel different from the PSFCH. Also, the terminal 20 may report the ability related to the simultaneous transmission of the PSFCH and the channel to another terminal 20 or the network.

[0140] i) The transmission priority in the above 1) may be determined by a predetermined method. For example, the priority may be determined based on the corresponding PSCCH / PSSCH reception or PSFCH transmission. Further, the priority may be treated as a specific priority and set, or may be predefined.

[0141] j) The terminal 20B may determine when to transmit and / or on which resources to transmit. The channel arranged on the determined resources may be called PSXCH. PSXCH may be at least one of PSCCH, PSSCH, PSFCH, PSBCH, and a new channel. When PSXCH is a new channel, for example, data and DM-RS may be frequency-division multiplexed, may be mapped to a plurality of PRBs, or may be encoded by Polar coding.

[0142] Also, information related to future resource reservation may be transmitted on the determined resources. For example, information indicating which PSFCH opportunity it is may be transmitted, or information indicating which frequency resources to use may be transmitted. Further, when the determined resources overlap with the PSFCH transmission and / or reception for HARQ feedback, for example, the PSFCH transmission and / or reception for HARQ feedback may be prioritized, or information related to the PSFCH transmission and / or reception and resource selection may be transmitted simultaneously. Rules for coordinating simultaneous transmission may be defined, and simultaneous transmission may be performed only when the conditions for simultaneous transmission are satisfied. When the conditions for simultaneous transmission are not satisfied, transmissions with lower priority may be dropped.

[0143] k) Further, the terminal 20B may always monitor the determined resources, that is, the resources related to the feedback channel. By always monitoring, the terminal 20B can transmit "specific information" at any time.

[0144] l) The terminal 20B may be requested by other terminals 20 as to when to transmit and / or on which resources to transmit. The channel arranged on the determined resources may be referred to as PSXCH. PSXCH may be at least one of PSCCH, PSSCH, PSFCH, PSBCH, and a new channel. When PSXCH is a new channel, for example, data and DM-RS may be frequency-division multiplexed, mapped to a plurality of PRBs, or encoded by Polar coding.

[0145] Also, information related to future resource reservation may be transmitted on the requested resources. For example, information indicating which PSFCH opportunity it is may be transmitted, or information indicating which frequency resources to use may be transmitted. Also, when the requested resources overlap with PSFCH transmission and / or reception for HARQ feedback, for example, PSFCH transmission and / or reception for HARQ feedback may be prioritized, or information related to PSFCH transmission and / or reception and resource selection may be transmitted simultaneously. Rules for coordinating simultaneous transmission may be defined, and simultaneous transmission may be performed only when the conditions for simultaneous transmission are met. When the conditions for simultaneous transmission are not met, transmissions with lower priority may be dropped. Also, the terminal 20B may always monitor the requested resources, that is, the resources related to the feedback channel. By always monitoring, the terminal 20B can transmit "specific information" at any time.

[0146] 2) Specific information in step S603 shown in FIG. 20 may be transmitted in the resources related to control information. For example, a dedicated SCI format may be defined as the resource, which may be a 1st stage SCI or a 2nd stage SCI. Also, for example, as the resource, a dedicated field of an existing SCI format (e.g., SCI format 1-A / 2-A / 2-B) may be used. Also, for example, as the resource, a combination of existing fields of an existing SCI format (e.g., SCI format 1-A / 2-A / 2-B) may be used. For example, the combination may be such that the cast type indicator field is not 10 (unicast) and the CSI request field is 1.

[0147] 3) Specific information may be transmitted via a new channel having the same length as PSCCH + PSSCH. For example, the length may be changed depending on the presence or absence of a PSFCH opportunity.

[0148] The terminal 20 that has received the "specific information" in step S603 shown in FIG. 20 may perform operations for avoiding collisions, for example, the operations shown in the following 1)-6). Transmission collisions can be avoided, and reliability and delay performance can be improved.

[0149] 1) Resource reselection may be performed based on specific information. 2) Resources may be dropped based on specific information. 3) Transmission power may be changed based on specific information. 4) Operations based on terminal implementation may be performed based on specific information. 5) Operations related to reevaluation or preemption may be performed based on specific information.

[0150] 6) The applicability of the above 1)-5) may be determined based on at least one of the information shown in the following a)-j).

[0151] a) Priority b) RSRP c) PDB d) Sensing result of terminal 20 that has received specific information e) Source of specific information f) Location information g) Resource allocation method (e.g., mode 1 or mode 2) h) Cast type i) Number of reserved resources j) Number of selected resources

[0152] Embodiments of the present invention may be applied to an operation in which a certain terminal 20 sets or allocates transmission resources of other terminals 20. That is, the transmission resources of other terminals 20 may be set or allocated so as to satisfy the conditions for resource selection or resource allocation according to embodiments of the present invention.

[0153] The above-described embodiments are not limited to V2X terminals and may be applied to terminals that perform D2D communication.

[0154] The operations according to the above-described embodiments may be performed only in a specific resource pool. For example, the operations according to the above-described embodiments may be performed only in a resource pool that can be used by terminals 20 after Release 17.

[0155] According to the above-described embodiments, the terminal 20 can reduce the collision probability of signals transmitted from other terminals 20 in a certain resource by transmitting specific information to other terminals 20 based on reservation information obtained by sensing.

[0156] That is, in direct communication between terminals, the reliability of communication during autonomous resource selection can be improved.

[0157] (Device configuration) Next, a functional configuration example of the base station 10 and the terminal 20 that execute the processes and operations described so far will be described. 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 some of the functions in the embodiments.

[0158] <Base Station 10> FIG. 31 is a diagram showing an example of the functional configuration of the base station 10. As shown in FIG. 31, the base station 10 includes a transmission unit 110, a reception unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in FIG. 31 is merely an example. As long as the operations according to the embodiments of the present invention can be executed, the functional divisions and the names of the functional units may be anything.

[0159] The transmission unit 110 includes a function of generating a signal to be transmitted to the terminal 20 side and wirelessly transmitting the signal. The reception unit 120 includes a function of receiving various signals transmitted from the terminal 20 and obtaining information of, for example, a higher layer from the received signals. Further, the transmission unit 110 has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL reference signals, etc. to the terminal 20.

[0160] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20 in a storage device and reads it out from the storage device as necessary. The content of the setting information is, for example, information related to the setting of D2D communication.

[0161] The control unit 140 performs processes related to the setting for the terminal 20 to perform D2D communication as described in the embodiments. Further, the control unit 140 transmits D2D communication and DL communication scheduling to the terminal 20 via the transmission unit 110. Further, the control unit 140 receives information related to the HARQ response of D2D communication and DL communication from the terminal 20 via the reception unit 120. A functional unit related to signal transmission in the control unit 140 may be included in the transmission unit 110, and a functional unit related to signal reception in the control unit 140 may be included in the reception unit 120.

[0162] <Terminal 20> FIG. 32 is a diagram showing an example of the functional configuration of the terminal 20. As shown in FIG. 32, the terminal 20 includes a transmission unit 210, a reception unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in FIG. 32 is merely an example. As long as the operations according to the embodiments of the present invention can be executed, the functional division and the names of the functional units can be anything.

[0163] The transmission unit 210 creates a transmission signal from the transmission data and wirelessly transmits the transmission signal. The reception unit 220 wirelessly receives various signals and obtains signals of a higher layer from the received physical layer signals. In addition, the reception unit 220 has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals, reference signals, etc. transmitted from the base station 10. Further, for example, the transmission unit 210 transmits PSCCH (Physical Sidelink Control Channel), PSSCH (Physical Sidelink Shared Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel), etc. to another terminal 20 as D2D communication, and the reception unit 220 receives PSCCH, PSSCH, PSDCH, or PSBCH, etc. from another terminal 20.

[0164] The setting unit 230 stores various setting information received from the base station 10 or the terminal 20 by the reception unit 220 in the storage device and reads it out from the storage device as necessary. In addition, the setting unit 230 also stores preset setting information. The content of the setting information is, for example, information related to the setting of D2D communication.

[0165] As described in the embodiments, the control unit 240 controls D2D communication for establishing an RRC connection with another terminal 20. Further, the control unit 240 performs processing related to power saving operation. Further, the control unit 240 performs processing related to HARQ for D2D communication and DL communication. Further, the control unit 240 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. Further, the control unit 240 may schedule D2D communication to another terminal 20. Further, the control unit 240 may autonomously select a resource to be used for D2D communication from a resource selection window based on the result of sensing, or may perform re-evaluation or preemption. Further, the control unit 240 performs processing related to power saving in transmission and reception of D2D communication. Further, the control unit 240 performs processing related to inter-terminal cooperation 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.

[0166] (Hardware Configuration) The block diagrams (FIGS. 31 and 32) used in the description of the above embodiments show blocks of functional units. These functional blocks (constituent parts) are realized by an arbitrary combination of at least one of hardware and software. Further, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one physically or logically combined device, or two or more physically or logically separated devices may be directly or indirectly (for example, using wired, wireless, etc.) connected and realized using these multiple devices. The functional block may be realized by combining software with the above one device or the above multiple devices.

[0167] Functions include, but are not limited to, judgment, decision-making, determination, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, solution, selection, selection, establishment, comparison, assumption, expectation, regarded as, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), assigning, etc. For example, a functional block (component) that enables transmission is called a transmitting unit or a transmitter. In any case, as described above, the implementation method is not particularly limited.

[0168] For example, the base station 10, the terminal 20, etc. in an embodiment of the present disclosure may function as a computer that performs the processing of the wireless communication method of the present disclosure. FIG. 33 is a diagram showing an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. Physically, the above-described base station 10 and terminal 20 may be 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, and the like.

[0169] In the following description, the term "device" 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 each device shown in the figure, or may be configured without including some devices.

[0170] Each function in the base station 10 and the terminal 20 is realized by causing the processor 1001 to perform operations by loading a predetermined software (program) onto hardware such as the processor 1001 and the storage device 1002, and controlling the communication by the communication device 1004, or controlling at least one of reading and writing data in the storage device 1002 and the auxiliary storage device 1003.

[0171] The processor 1001 controls the entire computer by operating an operating system, for example. The processor 1001 may be composed of a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, registers, and the like. For example, the above-described control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0172] Also, the processor 1001 reads a program (program code), software module, 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 according to these. As the program, a program for causing a computer to execute at least a part of the operations described in the above embodiments is used. For example, the control unit 140 of the base station 10 shown in FIG. 31 may be stored in the storage device 1002 and realized by a control program operating on the processor 1001. Also, for example, the control unit 240 of the terminal 20 shown in FIG. 32 may be stored in the storage device 1002 and realized by a control program operating on the processor 1001. Although it has been described that the above various processes are executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be mounted by one or more chips. Note that the program may be transmitted from a network via a telecommunication line.

[0173] The memory device 1002 is a computer-readable recording medium and may be constituted by at least one of, for example, ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. The memory device 1002 may be referred to as a register, a cache, a main memory (main storage device), etc. The memory device 1002 can store a program (program code), a software module, etc. executable for implementing the communication method according to an embodiment of the present disclosure.

[0174] The auxiliary storage device 1003 is a computer-readable recording medium and may be constituted by at least one of, for example, 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 disc, a digital versatile disc, a Blu-ray (registered trademark) disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-described storage medium may be, for example, a database, a server, or other appropriate medium including at least one of the memory device 1002 and the auxiliary storage device 1003.

[0175] The communication device 1004 is hardware (a transceiver device) for performing communication 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, a communication module, etc. The communication device 1004 may include, for example, a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, a transceiver antenna, an amplifier section, a transceiver section, a transmission line interface, etc. may be implemented by the communication device 1004. The transceiver section may be physically or logically separated into a transmitter section and a receiver section.

[0176] 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 external input. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. Note that the input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

[0177] Also, 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 for each device.

[0178] Further, the base station 10 and the terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0179] (Summary of Embodiment) As described above, according to the embodiment of the present invention, there is provided a terminal having a receiving unit that receives one or more reservation information related to the same resource from one or more other terminals, a control unit that determines whether a specific condition is satisfied, and a transmitting unit that transmits information related to the same resource to any of the other terminals when the control unit determines that the specific condition is satisfied.

[0180] With the above configuration, the terminal 20 can reduce the collision probability of signals transmitted from other terminals 20 in a certain resource by transmitting specific information to other terminals 20 based on reservation information obtained by sensing. That is, in direct communication between terminals, the reliability of communication during autonomous resource selection can be improved.

[0181] The same resource and the resource scheduled for transmission may at least partially overlap. With this configuration, the terminal 20 can reduce the collision probability of signals transmitted from other terminals 20 in a certain resource by transmitting specific information to other terminals 20 based on the resource scheduled for transmission and reservation information obtained by sensing.

[0182] The specific condition is that among the reservation information, there is first reservation information whose received power is greater than a threshold value, and the transmitting unit may transmit information related to the same resource to the terminal that transmitted the first reservation information. With this configuration, the terminal 20 can reduce the collision probability of signals transmitted from other terminals 20 in a certain resource by transmitting specific information to other terminals 20 with high interference based on the reservation information obtained by sensing.

[0183] The specific condition is that among the reservation information, there is second reservation information whose priority is lower than that of other reservation information, and the transmitting unit may transmit information related to the same resource to the terminal that transmitted the second reservation information. With this configuration, the terminal 20 can reduce the collision probability of signals transmitted from other terminals 20 in a certain resource by transmitting specific information to other terminals 20 that perform transmissions with low priority based on the reservation information obtained by sensing.

[0184] The information related to the same resource may be information indicating that the resources have collided. With this configuration, the terminal 20 can reduce the collision probability of signals transmitted from other terminals 20 in a certain resource by transmitting information indicating that the resources have collided to other terminals 20 based on the reservation information obtained by sensing.

[0185] Also, according to an embodiment of the present invention, there is provided a communication method in which a terminal executes a receiving procedure for receiving one or more pieces of reservation information related to the same resource from one or more other terminals, a control procedure for determining whether a specific condition is satisfied, and a transmitting procedure for transmitting information related to the same resource to any of the other terminals when it is determined that the specific condition is satisfied.

[0186] With the above configuration, the terminal 20 can reduce the collision probability of signals transmitted from other terminals 20 in a certain resource by transmitting specific information to other terminals 20 based on reservation information obtained by sensing. That is, in direct communication between terminals, the reliability of communication during autonomous resource selection can be improved.

[0187] (Supplement to the embodiment) As described above, the embodiments of the present invention have been explained. However, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various variations, modifications, alternatives, substitutions, etc. Although specific numerical examples have been used for explanation to facilitate understanding of the invention, unless otherwise specified, these numerical values are merely examples and any appropriate values may be used. The classification of items in the above description is not essential to the present invention, and matters described in two or more items may be used in combination as needed, or matters described in one item may be applied to matters described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical components. The operations of multiple functional units may be physically performed by one component, or the operation of one functional unit may be physically performed by multiple components. Regarding the processing procedures described in the embodiments, the order of processing may be changed as long as there is no contradiction. For the sake of convenience in explaining the processing, the base station 10 and the terminal 20 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. Software operating on a processor included in the base station 10 according to an embodiment of the present invention and software operating on a processor included in the terminal 20 according to an embodiment of the present invention may be stored in any appropriate storage medium such as a random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk drive (HDD), removable disk, CD-ROM, database, server, or the like.

[0188] Furthermore, the notification of information is not limited to the aspects / embodiments described in this disclosure, and other methods may be used. For example, the notification of information may be implemented by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, notification information (MIB (Master Information Block), SIB (System Information Block)), other signals or combinations thereof. Also, 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, etc.

[0189] Each aspect / embodiment described in this disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), other suitable systems, and next-generation systems extended based thereon. Also, multiple systems may be combined (e.g., a combination of at least one of LTE and LTE-A and 5G, etc.) and applied.

[0190] For each aspect / embodiment processing procedure, sequence, flowchart, etc. described in this specification, the order may be changed as long as there is no contradiction. For example, for the methods described in this disclosure, the elements of various steps are presented using an exemplary order and are not limited to the specific order presented.

[0191] Specific operations assumed to be performed by the base station 10 in this specification may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having the base station 10, various operations performed for communication with the terminal 20 can clearly be performed by at least one of the base station 10 and other network nodes other than the base station 10 (for example, but not limited to, an MME or an S-GW, etc.). Although the case where there is one other network node other than the base station 10 is exemplified above, the other network node may be a combination of a plurality of other network nodes (for example, an MME and an S-GW).

[0192] The information or signals, etc. described in this disclosure can be output from an upper layer (or a lower layer) to a lower layer (or an upper layer). They may be input and output via a plurality of network nodes.

[0193] The input and output information, etc. may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information, etc. can be overwritten, updated, or appended. The output information, etc. may be deleted. The input information, etc. may be transmitted to other devices.

[0194] The determination in this disclosure may be made by a value represented by 1 bit (0 or 1), or by a Boolean value (true or false), or by a numerical comparison (for example, comparison with a predetermined value).

[0195] Software should be broadly construed to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc., whether called software, firmware, middleware, microcode, hardware description language, or by any other name.

[0196] Also, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, when software is transmitted from a website, server, or other remote source using at least one of wired technologies (such as coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technologies (such as infrared, microwave, etc.), at least one of these wired and wireless technologies is included within the definition of a transmission medium.

[0197] 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., which may be referred to throughout the above description, may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0198] Note that terms described 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). Also, a signal may be a message. Also, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0199] The terms "system" and "network" used in this disclosure are used interchangeably.

[0200] In addition, the information, parameters, etc. described in this disclosure may be represented using absolute values, relative values from a predetermined value, or other corresponding information. For example, radio resources may be indicated by an index.

[0201] The names used for the above-described parameters are not limiting in any way. Furthermore, mathematical formulas and the like using these parameters may be different from those explicitly disclosed in this disclosure. Since various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, the various names assigned to these various channels and information elements are not limiting in any way.

[0202] In this disclosure, terms such as "base station (BS: Base Station)", "radio base station", "base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", "component carrier", etc. may be used interchangeably. A base station may also be referred to by terms such as macrocell, small cell, femtocell, picocell, etc.

[0203] A base station can accommodate one or more (e.g., three) cells. When the base station accommodates a plurality of cells, the entire coverage area of the base station can be divided into a plurality of smaller areas, and each of the smaller areas can also provide communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The term "cell" or "sector" refers to a part or the whole of the coverage area of at least one of a base station and a base station subsystem that provides communication services in this coverage.

[0204] In the present disclosure, terms such as "mobile station (MS)", "user terminal", "user equipment (UE)", and "terminal" can be used interchangeably.

[0205] A mobile station may also be called by those skilled in the art as a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other appropriate terms.

[0206] At least one of the base station and the mobile station may also be called a transmitting device, a receiving device, a communication device, etc. Note that at least one of the base station and the mobile station may also be a device mounted on a moving body, the moving body itself, etc. The moving body may be a vehicle (e.g., a car, an airplane, etc.), a moving body that moves without a driver (e.g., a drone, an autonomous vehicle, etc.), or a robot (humanoid or non-humanoid). Note that at least one of the base station and the mobile station also includes a device that does 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.

[0207] In addition, the base station in the present disclosure may be replaced by a user terminal. For example, for a configuration in which communication between the base station and the user terminal is replaced with communication between a plurality of terminals 20 (which may be referred to as, for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.), each aspect / embodiment of the present disclosure may be applied. In this case, the functions of the above-described base station 10 may be configured to be functions of the terminal 20. Further, terms such as "uplink" and "downlink" may be replaced with terms corresponding to inter-terminal communication (for example, "side"). For example, the uplink channel, downlink channel, etc. may be replaced with side channels.

[0208] Similarly, the user terminal in the present disclosure may be replaced by a base station. In this case, the functions of the above-described user terminal may be configured to be functions of the base station.

[0209] As used herein, the terms "determining" and "deciding" may encompass a variety of operations. "Determining" and "deciding" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up (e.g., searching a table, database, or other data structure), ascertaining, and considering something as having been "determined" or "decided." "Determining" and "deciding" may also include receiving (e.g., receiving information), transmitting (e.g., transmitting information), inputting, outputting, accessing (e.g., accessing data in a memory), and considering something as having been "determined" or "decided." "Determining" and "deciding" may further include resolving, selecting, choosing, establishing, comparing, and considering something as having been "determined" or "decided." That is, "determining" and "deciding" may include considering something as having determined or decided some action. Also, "determining (deciding)" may be read as "assuming," "expecting," "considering," etc.

[0210] The terms "connected" or "coupled", or any variations thereof, mean any direct or indirect connection or coupling between two or more elements, and can 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 can be physical, logical, or a combination thereof. For example, "connected" may be read as "accessed". As used in this disclosure, two elements can be considered to be "connected" or "coupled" to each other using at least one of one or more wires, cables, and printed electrical connections, and also using, as some non-limiting and non-exhaustive examples, electromagnetic energy having wavelengths in the radio frequency region, microwave region, and optical (both visible and invisible) region, etc.

[0211] The reference signal can also be abbreviated as RS (Reference Signal) and may be called a Pilot depending on the applicable standard.

[0212] As used in this disclosure, the description "based on" does not mean "based only on" unless otherwise specified. In other words, the description "based on" means both "based only on" and "based at least on".

[0213] Any reference to an element using designations such as "first", "second", etc. used in this disclosure does not generally limit the quantity or order of those elements. These designations can be used in this disclosure as a convenient way to distinguish between two or more elements. Thus, a reference to a first and a second element does not mean that only two elements can be employed, or that the first element must precede the second element in any form.

[0214] In the configuration of each of the above devices, "means" may be replaced with "section", "circuit", "device", etc.

[0215] In the present disclosure, when the terms "include", "including" and their variants are used, these terms are intended to be inclusive in the same manner as the term "comprising". Further, the term "or" used in the present disclosure is not intended to be an exclusive disjunction.

[0216] A wireless 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 referred to as a subframe. The subframe may further be composed of one or more slots in the time domain. The subframe may have a fixed time length (e.g., 1 ms) that does not depend on numerology.

[0217] Numerology may be a communication parameter applied to at least one of transmission and reception of a certain signal or channel. Numerology may indicate, for example, at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, wireless frame configuration, specific filtering processing performed by a transceiver in the frequency domain, specific windowing processing performed by a transceiver in the time domain, etc.

[0218] A slot may be composed of one or more symbols (such as OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.) in the time domain. The slot may be a time unit based on numerology.

[0219] A slot may include a plurality of mini-slots. Each mini-slot may be composed of one or more symbols in the time domain. Also, a mini-slot may be called a sub-slot. A mini-slot may be composed of a smaller number of symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may be called a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be called a PDSCH (or PUSCH) mapping type B.

[0220] A radio frame, sub-frame, slot, mini-slot, and symbol all represent time units for transmitting signals. Different names corresponding to each of them may also be used.

[0221] For example, one sub-frame may be called a Transmission Time Interval (TTI), a plurality of consecutive sub-frames may be called a TTI, or one slot or one mini-slot may be called a TTI. That is, at least one of the sub-frame and the TTI may be a sub-frame (1 ms) in the existing LTE, a period shorter than 1 ms (e.g., 1 - 13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, a mini-slot, etc. instead of a sub-frame.

[0222] Here, the TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (frequency bandwidth, transmission power, etc. that can be used at each terminal 20) to each terminal 20 in TTI units. Note that the definition of the TTI is not limited to this.

[0223] The TTI may be a transmission time unit such as a channel-encoded data packet (transport block), a code block, a codeword, etc., or may be a processing unit such as scheduling and link adaptation. When the TTI is given, the time interval (e.g., the number of symbols) in which a transport block, a code block, a codeword, etc. are actually mapped may be shorter than the TTI.

[0224] Note that when one slot or one mini-slot is called a TTI, one or more TTIs (i.e., one or more slots or one or more mini-slots) may be the minimum time unit of scheduling. Also, the number of slots (mini-slots) constituting the minimum time unit of the scheduling may be controlled.

[0225] A TTI having a time length of 1 ms may be called a normal TTI (TTI in LTE Rel.8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a slot, etc. A TTI shorter than the normal TTI may be called a shortened TTI, a short TTI, a partial TTI, a shortened subframe, a short subframe, a mini-slot, a sub-slot, a slot, etc.

[0226] Note that the long TTI (e.g., the normal TTI, subframe, etc.) may be read as a TTI having a time length exceeding 1 ms, or the short TTI (e.g., the shortened TTI, etc.) may be read as a TTI having a TTI length less than that of the long TTI and equal to or more than 1 ms.

[0227] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or a plurality of consecutive subcarriers in the frequency domain. The number of subcarriers included in the RB may be the same regardless of the numerology, and may be, for example, 12. The number of subcarriers included in the RB may be determined based on the numerology.

[0228] Also, the time domain of the RB may include one or more symbols, and may be the length of 1 slot, 1 mini-slot, 1 sub-frame, or 1 TTI. 1 TTI, 1 sub-frame, etc. may each be composed of one or more resource blocks.

[0229] Note that one or more RBs may be referred to as physical resource blocks (PRBs), sub-carrier groups (SCGs), resource element groups (REGs), PRB pairs, RB pairs, etc.

[0230] Also, the resource block may be composed of one or more resource elements (REs). For example, 1 RE may be a radio resource area of 1 sub-carrier and 1 symbol.

[0231] The bandwidth part (BWP) (which may also be called a partial bandwidth, etc.) may represent a subset of consecutive common resource blocks (common RBs) for a certain numerology in a certain carrier. Here, the common RB may be specified by the index of the RB based on the common reference point of the carrier. The PRB may be defined in a certain BWP and numbered within that BWP.

[0232] The BWP may include a BWP for UL (UL BWP) and a BWP for DL (DL BWP). For the terminal 20, one or more BWPs may be set within one carrier.

[0233] At least one of the set BWPs may be active, and the terminal 20 may not be assumed to transmit and receive a predetermined signal / channel outside the active BWP. Note that "cell", "carrier", etc. in the present disclosure may be read as "BWP".

[0234] The structures such as the above-described radio frames, sub-frames, slots, mini-slots, and symbols are merely examples. For example, the number of sub-frames included in a radio frame, the number of slots per sub-frame or radio frame, the number of mini-slots included in a slot, the number of symbols and RBs included in a slot or mini-slot, the number of sub-carriers included in an RB, and the number of symbols, symbol length, cyclic prefix (CP) length, etc. within a TTI can be changed in various ways.

[0235] In the present disclosure, for example, when articles are added by translation, such as a, an, and the in English, the present disclosure may include that the nouns following these articles are in the plural form.

[0236] In the present disclosure, the term "A is different from B" may mean that "A and B are different from each other". Note that this term may also mean that "A and B are each different from C". Terms such as "separate", "coupled", etc. may also be interpreted in the same way as "different".

[0237] In the present disclosure, each aspect / embodiment described may be used alone, in combination, or switched and used during execution. Also, the notification of predetermined information (for example, the notification of "being X") is not limited to being explicitly performed, and may be performed implicitly (for example, by not performing the notification of the predetermined information).

[0238] As described above in detail regarding the present disclosure, it is obvious to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented as modified and changed aspects without departing from the spirit and scope of the present disclosure determined by the description of the claims. Therefore, the description of the present disclosure is for the purpose of illustrative explanation and has no restrictive meaning for the present disclosure.

Description of Reference Numerals

[0239] 10 Base station 110 Transmission unit 120 Reception unit 130 Setting unit 140 Control unit 20 Terminal 210 Transmission unit 220 Reception unit 230 Setting unit 240 Control unit 1001 Processor 1002 Memory device 1003 Auxiliary memory device 1004 Communication device 1005 Input device 1006 Output device

Claims

1. A first terminal, comprising: a receiving unit configured to receive first reservation information for reserving a first resource from a second terminal and second reservation information for reserving a second resource from a third terminal; a control unit configured to determine whether a specific condition based on a first time from reception of the first reservation information or the second reservation information to a resource for transmitting information regarding a collision between the first resource and the second resource and a second time from the resource for transmitting the information regarding the collision to a resource where the collision may occur is satisfied; a transmitting unit configured to transmit the information regarding the collision when the control unit determines that the specific condition is satisfied; The terminal having the above components.

2. The specific condition is that the first time is equal to or greater than a value given by a higher layer parameter and the second time is equal to or greater than a value corresponding to a subcarrier interval. The terminal according to Claim 1.

3. The control unit determines a destination terminal of the information regarding the collision based on whether the first time is equal to or greater than a value given by a higher layer parameter. The terminal according to Claim 1.

4. The control unit determines a destination terminal of the information regarding the collision based on whether cooperative operation between terminals is possible. The terminal according to Claim 1.

5. The control unit determines a destination terminal of the information regarding the collision based on a priority related to the first reservation information and a priority related to the second reservation information. The terminal according to Claim 1.

6. The transmitting unit transmits the information regarding the collision via a feedback channel for communication between terminals. The terminal according to Claim 1.

7. A communication method executed by a first terminal, the method comprising: receiving first reservation information for reserving a first resource from a second terminal and second reservation information for reserving a second resource from a third terminal; determining whether a specific condition based on a first time from reception of the first reservation information to a resource for transmitting information regarding a collision between the first resource and the second resource and a second time from the resource for transmitting the information regarding the collision to a resource where the collision may occur is satisfied; transmitting the information regarding the collision when it is determined that the specific condition is satisfied. The communication method having the above steps.

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