Terminal and Communication Method

Abstract

A terminal according to the present invention comprises: a transmission unit which performs random selection of a resource in a resource pool; a reception unit which receives control information from another terminal in a first period in the resource pool; and a control unit which performs reevaluation of the randomly selected resource or check of preemption, on the basis of the control information.

Description

Technical Field

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

Background Art

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

[0003] D2D reduces the 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 directly communicating between terminals. Hereinafter, when not particularly distinguishing D2D communication, D2D discovery, etc., it is simply referred to as D2D. Also, a signal transmitted and received by D2D is referred to as a D2D signal. Various use cases of services related to V2X (Vehicle to Everything) in NR have been studied (for example, Non-Patent Document 2).

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non - Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] As an enhancement of NR sidelink, 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 based on the result, selects available resource candidates from the resource selection window.

[0007] Also, based on inter - UE coordination as a baseline, enhanced Ultra - Reliable Low - Latency Communication (eURLLC) is being considered. For example, terminal 20A shares information indicating a resource set with terminal 20B, and terminal 20B may consider this information in resource selection for transmission.

[0008] On the other hand, in Resource Allocation Mode 2, an operation of making a random selection to determine resources without performing sensing is also assumed. Since no sensing is performed in random selection, it is not possible to perform re - evaluation or pre - emption check on the selected resources, which may reduce the reliability or delay performance of sidelink transmission.

[0009] 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

[0010] According to the disclosed technology, in a resource pool, a transmission unit that performs random selection of resources, a reception unit that receives control information from other terminals in the first period in the resource pool, and a control unit that performs re-evaluation of the randomly selected resources or checks for preemption based on the control information are provided. The control unit determines the start time of the first period based on the position of the time region at the head of the second period in which a resource is randomly selected or the position of the time region of the randomly selected resource. A terminal is provided.

Advantages of the Invention

[0011] 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

[0012]

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Embodiments for Carrying Out the Invention

[0013] 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.

[0014] 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 subsequent systems (e.g., NR) after LTE-Advanced, or wireless LAN (Local Area Network) unless otherwise specified.

[0015] 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.).

[0016] Also, in the embodiment of the present invention, the fact that wireless parameters, etc. are "configured" may mean that predetermined values are pre-configured, or that wireless parameters notified from the base station 10 or the terminal 20 are configured.

[0017] FIG. 1 is a diagram for explaining V2X. In 3GPP, it is considered to realize V2X (Vehicle to Everything) or eV2X (enhanced V2X) by expanding the D2D function, and standardization is underway. 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 possessed by a pedestrian.

[0018] 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 - based V2X, studies are underway to achieve large capacity, low latency, high reliability, and QoS (Quality of Service) control.

[0019] Regarding LTE or NR - based V2X, it is assumed that studies will proceed not only limited to 3GPP specifications in the future. For example, ensuring interoperability, reducing costs through upper - layer implementation, combined use or switching methods of multiple RATs (Radio Access Technologies), regulatory compliance in each country, data acquisition, distribution, database management, and utilization methods of the LTE or NR - based V2X platform are assumed to be studied.

[0020] In the embodiments of the present invention, a form in which the 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, or the communication device may be a device mounted on a drone or an aircraft, or the communication device may be a base station, an RSU, a relay station (relay node), a terminal having scheduling capabilities, etc.

[0021] 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 referred to (including SLSS (Sidelink Synchronization Signal)) 4) Reference signals used for path loss measurement for transmit power control

[0022] 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.

[0023] In LTE SL, Mode3 and Mode4 are defined for the SL resource allocation to terminal 20. In Mode3, transmission resources are dynamically allocated by DCI (Downlink Control Information) transmitted from base station 10 to terminal 20. Also, SPS (Semi Persistent Scheduling) is possible in Mode3. In Mode4, terminal 20 autonomously selects transmission resources from the resource pool.

[0024] Note that in the embodiments of the present invention, a slot may be read as a symbol, a mini-slot, a sub-frame, a radio frame, or a TTI (Transmission Time Interval). Also, in the embodiments of the present invention, a cell 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 a wireless LAN), etc.

[0025] Note that in the embodiments of the present invention, terminal 20 is not limited to a V2X terminal and may be any type of terminal that performs D2D communication. For example, 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.

[0026] Figure 2 is a diagram for explaining an example (1) of the transmission mode of V2X. In the transmission mode of sidelink communication shown in Figure 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 the PSSCH (Physical Sidelink Shared Channel) to the terminal 20B based on the received scheduling (step 2). The transmission mode of sidelink communication shown in Figure 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 Figure 2 may be referred to as sidelink transmission mode 1 in NR.

[0027] Figure 3 is a diagram for explaining an example (2) of the transmission mode of V2X. In the transmission mode of sidelink communication shown in Figure 3, in step 1, the terminal 20A transmits the PSCCH and the PSSCH to the terminal 20B using the resources autonomously selected. The transmission mode of sidelink communication shown in Figure 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.

[0028] 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.

[0029] 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 sidelink resource pattern 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.

[0030] 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.

[0031] Figure 7 is a diagram for explaining an example (1) of the communication type of V2X. The communication type of 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.

[0032] 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 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 terminals 20B and 20C, and the terminal 20A performs groupcast to the group.

[0033] 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 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.

[0034] In addition, in NR-V2X, it is assumed that HARQ (Hybrid automatic repeat request) is supported for unicast and groupcast of the sidelink. Furthermore, in NR-V2X, SFCI (Sidelink Feedback Control Information) including HARQ responses is defined. Furthermore, it is being considered that SFCI is transmitted via the PSFCH (Physical Sidelink Feedback Channel).

[0035] Note that in the following description, it is assumed that 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, or 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.

[0036] 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.

[0037] 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.

[0038] Hereinafter, when the terminals 20A, 20B, etc. are not particularly distinguished, they are simply described as "terminal 20" or "user device". FIG. 10 shows, as an example, a case where both the terminal 20A and the terminal 20B are within the coverage of the cell, but the operations in the embodiment of the present invention can also be applied when the terminal 20B is outside the coverage.

[0039] 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.

[0040] Note that the terminal 20 does not necessarily have 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.

[0041] Also, the processing content of the sidelink transmission data of the terminal 20 is basically the same as that 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.

[0042] 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).

[0043] 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.

[0044] 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, may be defined in advance by the specification, or the predetermined period may be referred to as an interval in the time domain.

[0045] In steps S102 and S103, the terminal 20A transmits SCI (Sidelink Control Information) by using the resources autonomously selected in step S101 through PSCCH and / or PSSCH, and transmits SL data by using 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.

[0046] 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 resources 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.

[0047] In step S104, the terminal 20B transmits HARQ-ACK for the received data to the terminal 20A by using the resources of PSFCH determined from the received SCI.

[0048] 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.

[0049] Note that steps S104 and S105 may not be executed when HARQ control with HARQ feedback is not executed.

[0050] 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.

[0051] 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.

[0052] In steps S202 and S203, the terminal 20A transmits the SCI by the PSCCH and / or PSSCH and transmits the SL data by the PSSCH using the resources autonomously selected in step S201. 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.

[0053] In step S204, the terminal 20A retransmits the SCI by the PSCCH and / or PSSCH and the SL data by the PSSCH to the terminal 20B using the resources autonomously selected in step S201. The retransmission in step S204 may be executed a plurality of times.

[0054] Note that if blind retransmission is not executed, step S204 may not be executed.

[0055] 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 the sidelink resources used by the terminal 20 and transmit information indicating the resources to the terminal 20. Further, when HARQ control with HARQ feedback is applied, the base station 10 may transmit information indicating the resources of the PSFCH to the terminal 20.

[0056] In step S301, the base station 10 performs sidelink scheduling by transmitting DCI (Downlink Control Information) to the terminal 20A by the PDCCH. Hereinafter, for convenience, the DCI for sidelink scheduling is referred to as sidelink scheduling DCI.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In step S304, the terminal 20B transmits a HARQ-ACK for the received data to the terminal 20A using the resource of the PSFCH determined from the received SCI.

[0062] In step S305, the terminal 20A transmits a HARQ-ACK at a timing (e.g., slot-based timing) specified by, for example, DL scheduling DCI (or SL scheduling DCI) 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 codebook of the HARQ-ACK does not include the HARQ-ACK for DL data.

[0063] Note that if HARQ control involving HARQ feedback is not executed, step S304 and / or step S305 may not be executed.

[0064] FIG. 13 is a sequence diagram showing an operation example (4) of V2X. As described above, in the side link of NR, it is supported that the HARQ response is transmitted by the PSFCH. Note that, as the format of the PSFCH, for example, a format similar to the PUCCH (Physical Uplink Control Channel) format 0 can be used. That is, the format of the PSFCH may be a sequence-based format in which the PRB (Physical Resource Block) size is 1 and ACK and NACK are identified by the difference in sequence and / or cyclic shift. The format of the PSFCH is not limited to this. The resource of the PSFCH may be arranged in the symbol at the end of the slot or a plurality of symbols at the end. Also, a period N is set or predefined for the PSFCH resource. The period N may be set or predefined in units of slots.

[0065] 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 the slot, or in a plurality of symbols from the beginning, or in a plurality of symbols from a symbol other than the beginning. The PSFCH may be arranged in 1 symbol at the end of the slot, or in a plurality of symbols at the end of the slot. Note that the above-mentioned "beginning of the slot" and "end of the slot" may omit the consideration of symbols for AGC (Automatic Gain Control) and symbols for transmission / reception switching. That is, for example, when 1 slot is composed of 14 symbols, the "beginning of the slot" and "end of the 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 sub-channels are set in the 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.

[0066] 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 to be used for the transmission and reception of the PSFCH. As shown in FIG. 13, in step S401, the terminal 20A, which is the transmitting terminal 20, performs groupcast to the terminals 20B, 20C, and 20D, which are the receiving 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 terminals 20 belonging to the group, it is necessary to determine how to allocate the PSFCH resources. Note that the transmitting terminal 20 may know the number of receiving terminals 20 in the groupcast. Note that in the groupcast option 1, only NACK is transmitted as the HARQ response, and ACK is not transmitted.

[0067] 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 and performs transmission. As shown in FIG. 14, the terminal 20 performs sensing in the sensing window within the resource pool. By sensing, the terminal 20 receives the resource reservation field or the resource assignment field included in the SCI transmitted from another terminal 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.

[0068] 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 10240 milliseconds. FIG. 14 shows the slot t0 SLfrom slot t Tmax SL This is an example where the period from this to slot t is set as a resource pool. The resource pool within each period may have its area set by, for example, a bitmap.

[0069] Also, as shown in FIG. 14, the transmission trigger in the terminal 20 occurs in slot n, and the priority of this transmission is p TX Let's assume so. The 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 . When 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, when 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 .

[0070] Also, as in slot t shown 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.

[0071] 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 of resource candidates A may be set to 20% or more of the resource selection window. If S A 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.

[0072] 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 resource to be used. The terminal 20 may perform sidelink transmission using the determined resource.

[0073] 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.

[0074] 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 of resource candidates A and selects the resource to be used for transmission (S502). Subsequently, the terminal 20 sets the set S of resource candidates ASelect a resource set (r_0, r_1, ···) for determining preemption (S503). The resource set may be notified from the upper layer to the PHY layer as a resource for determining whether preemption has occurred.

[0075] In step S504, the terminal 20 re-identifies each resource within the resource selection window based on the sensing result at the timing of T(r_0) - T3 shown in FIG. 16, and determines a set S A of resource candidates, and further determines preemption for the resource set (r_0, r_1, ···) based on the priority. For example, r_1 shown in FIG. 16 has a SCI transmitted from another terminal 20 detected by re-sensing and is not included in S A . If preemption is valid and 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 the lower the value indicating the priority, the higher the priority. That is, if the value prio_RX indicating the priority of the SCI transmitted from another terminal 20 is higher than the value prio_TX indicating the priority of the transport block transmitted from the own terminal, the terminal 20 does not exclude the resource r_1 from S A . Or, if preemption is only valid for a specific priority (for example, sl-PreemptionEnable is any 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.

[0076] In step S505, when preemption is determined in step S504, the terminal 20 notifies the upper layer of the preemption, the upper layer reselects resources, and the check of the preemption ends.

[0077] In addition, when re-evaluation is executed instead of the check of the preemption, in the above step S504, after the set S of resource candidates is determined, if the resources of the resource set (r_0, r_1, ···) are not included in S, the resources are not used, and the upper layer reselects resources. A After determining S A If the resources of the resource set (r_0, r_1, ···) are not included in S, the resources are not used, and the upper layer reselects resources.

[0078] Here, in the NR Release 17 side link, power saving based on 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 the 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.

[0079] 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, the terminal 20A may share information indicating the resource set with the terminal 20B, and the terminal 20B may consider the information in resource selection for transmission.

[0080] For example, as a resource allocation method in sidelink, the terminal 20 may perform full sensing as shown in FIG. 14. Further, the terminal 20 may perform resource identification by sensing only limited resources as compared with full sensing, and perform partial sensing for resource selection from the identified resource set. Further, the terminal 20 may perform random selection in which the resources within the resource selection window are used as the identified resource set without excluding the resources within the resource selection window, and perform resource selection from the identified resource set.

[0081] In Release 17, the operation may be defined assuming two types of terminals 20. One is type A, and the terminal 20 of type A does not have the ability to receive any sidelink signals and channels. However, it may be an exception to receive the PSFCH and S-SSB.

[0082] The other one is type D, and the terminal 20 of type D has the ability to receive all sidelink signals and channels defined in Release 16. However, it does not exclude receiving some sidelink signals and channels.

[0083] Also, in Release 17, a plurality of resource allocation methods may be set in a certain resource pool.

[0084] Here, in the terminal 20 that has the receiver function of the sidelink signal and performs PSCCH / PSSCH transmission by random selection, a method for applying re-evaluation or preemption check has not been established. For the resource selected by random selection, when the terminal 20 has the receiver function of the sidelink signal, the collision probability can be reduced by performing re-evaluation or preemption check before transmission. Also, the power saving effect can be maintained by performing re-evaluation or preemption check after random selection rather than performing full sensing or partial sensing.

[0085] Therefore, a terminal 20 having a receiving function for sidelink signals and performing resource selection by random selection may receive SCI from other terminals 20 during a predetermined period, and perform re-evaluation or preemption check based on the received information. Hereinafter, the description of "re-evaluation or preemption check" may be replaced with "re-evaluation and / or preemption check".

[0086] FIG. 17 is a flowchart for explaining an example of communication in an embodiment of the present invention. In step S601, the terminal 20 performs random selection. In the subsequent step S602, the terminal 20 receives SCI from other terminals 20 during a predetermined period. In the subsequent step S603, the terminal 20 performs a re-evaluation or preemption check based on the received SCI.

[0087] By performing communication as shown in FIG. 17, it is possible to reduce the transmission collision probability even in the resource pool used by the terminal 20 that performs resource selection by random selection.

[0088] FIG. 18 is a diagram for explaining an example (1) of re-evaluation or preemption check in an embodiment of the present invention. The predetermined period in step S602 above may be called a sensing window. The start timing of the predetermined period may be determined based on at least one of the timings shown in FIGS. 18 of 1)-7) below.

[0089] 1) Packet arrival: n0 2) Random resource selection: n1 3) Resource selection window: from n2 to n3 4) Range of time resource assignment field: from 0 slot to 31 slots 5) Resource reservation period field: set candidate value 6) Selected resources: m0, m1, ··· 7) Re-evaluation or preemption check: k (i.e., m0 - processing time T3)

[0090] For example, the predetermined period in step S602 may start from n0. Also, for example, the predetermined period may start from n1. Also, for example, the predetermined period may start from n2 - 31. Also, for example, the predetermined period may start from m0 - 31. Also, for example, the predetermined period may start from the timing that is later in time among n0 and n2 - 31. Note that n0 and n1 may be at the same timing.

[0091] FIG. 19 is a diagram for explaining an example (2) of re-evaluation or preemption check in an embodiment of the present invention. The end timing of the predetermined period in step S602 may be determined based on at least one of the timings shown in FIGS. 19 of 1) - 5) below.

[0092] 1) Resource reservation cycle field: Set candidate value 2) Selected resources: m0, m1, ··· 3) Re-evaluation or preemption check: k (i.e., m0 - processing time T3) 4) Time interval at the time of re-evaluation or preemption check (resource identification candidate): from n2' to n3' 5) Processing time T proc,0

[0093] For example, the predetermined period in step S602 may end at k - T proc,0 . Note that n2' may be at the same timing as n2, and n3' may be at the same timing as n3.

[0094] Note that in some slots of the predetermined period, reception may not need to be executed. For example, in the slots where the terminal 20 has transmitted during the predetermined period, reception may not need to be executed.

[0095] The information used for the re-evaluation or preemption check in step S603 above may be at least one of the information shown in the following 1) to 6) among the SCIs received during the predetermined period in step S602 above.

[0096] 1) Priority 2) Time resource allocation field 3) Frequency resource assignment field 4) Resource reservation period field 5) Field related to resource allocation type (for example, a field notifying full sensing, partial sensing, or random selection)

[0097] For example, the terminal 20 may execute the re-evaluation or preemption check based on the reservation by the time resource allocation field (that is, the reservation from after 0 slots to after 31 slots) while ignoring the resource reservation period field.

[0098] Also, the terminal 20 may execute the re-evaluation or preemption check in step S603 above based on the timing at which the own device transmitted. For example, in the slot in which the terminal 20 transmitted, the terminal 20 may execute the re-evaluation or preemption check based on the time resource allocation field or the resource reservation period field that can be indicated by other terminals 20.

[0099] Also, parameters used for the operation of the re-evaluation or preemption check executed by the terminal 20 that selects resources by random selection may be defined. For example, the parameters may be different from the parameters for resource selection by full sensing or partial sensing. Also, for example, the parameters may be different from the parameters for the re-evaluation or preemption check executed by the terminal 20 that selects resources by full sensing or partial sensing.

[0100] In addition, the parameters used for the operation of re-evaluation or preemption check executed by the terminal 20 that performs resource selection by random selection may be at least one of the following 1) and 2).

[0101] 1) Upper layer parameters that determine the validity / invalidity of re-evaluation or preemption check. The upper layer parameters may be parameters set for each priority.

[0102] 2) Parameters for determining resource identification candidates (parameters related to the selection window). For example, it may be T2min for each priority, or an RSRP threshold value set for each (transmission priority, reception priority), or the type of RSRP measurement target channel for sensing, that is, PSCCH or PSSCH, or Tp roc,1 may also be.

[0103] Note that when the selection window is [n+T1, n+T2], the terminal 20 determines T1 and T2 so as to satisfy the following 1) and 2). 1) 0 ≦ T1 ≦ T proc,1 2) T2min ≦ T2 ≦ remaining PDB (Packet delay budget)

[0104] In addition, the operation of re-evaluation or preemption check executed by the terminal 20 that performs resource selection by random selection may be the same as the operation of re-evaluation or preemption check executed by the terminal 20 that performs resource selection by full sensing or partial sensing. However, the sensing target may be the predetermined period in step S602 described above, or the information used may be the information used for the re-evaluation or preemption check in step S603.

[0105] In addition, the operation of re-evaluation or preemption check performed by the terminal 20 that selects resources by random selection may be different from the operation of re-evaluation or preemption check performed by the terminal 20 that selects resources by full sensing or partial sensing. For example, without defining a selection window, only the resources scheduled for use are identified as the objects to be identified, and the availability of the resources may be determined based on the presence, priority, and RSRP of other terminals 20 that reserve the resources.

[0106] In addition, when it is determined by the re-evaluation or preemption check performed by the terminal 20 that selects resources by random selection that at least a part of the selected resources cannot be used, a predetermined operation shown in 1) or 2) below may be executed.

[0107] 1) The terminal 20 may execute a resource reselection operation. For example, resource reselection may be performed by random selection. For example, resource selection may be randomly performed from the identified resource set during the re-evaluation or preemption check.

[0108] 2) When there are some resources that can be used, the terminal 20 may use the resources without performing reselection. For example, resource reselection may be executed only when there are no available resources.

[0109] In addition, when the terminal 20 that selects resources by random selection detects that the transmission of a certain transport block has been successful, it may not apply the re-evaluation or preemption check to the reserved resources. Detecting that the transmission has been successful may mean receiving an ACK (at the time of ACK / NACK feedback), or may mean not receiving a NACK (at the time of NACK-only feedback). Also, at the timing when it is detected that the transmission has been successful, the SCI reception operation in step S602 above may be terminated.

[0110] Note that the above-described embodiments may be applied to an operation in which a certain terminal 20 sets or allocates transmission resources of another terminal 20. That is, resource setting or allocation may be executed so that the above-described embodiments are satisfied.

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

[0112] The operations according to the above-described embodiments may be executed only in a specific resource pool. For example, it may be executed only in a resource pool that can be used by terminals 20 after Release 17.

[0113] According to the above-described embodiments, it is possible to reduce the probability that the side-link signal transmission of the terminal 20 that executes random selection in the side link collides with the side-link signal transmission by another terminal 20.

[0114] That is, in direct communication between terminals, it is possible to improve the reliability of communication during autonomous resource selection.

[0115] (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.

[0116] <Base Station 10> FIG. 20 is a diagram showing an example of the functional configuration of the base station 10. As shown in FIG. 20, 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. 20 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 may be any.

[0117] 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.

[0118] The setting unit 130 stores setting information set in advance 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.

[0119] As described in the embodiment, the control unit 140 performs processing related to the setting for the terminal 20 to perform D2D communication. Further, the control unit 140 transmits scheduling of D2D communication and DL communication 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.

[0120] <Terminal 20> FIG. 21 is a diagram showing an example of the functional configuration of the terminal 20. As shown in FIG. 21, 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. 21 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 may be any.

[0121] 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 acquires signals of a higher layer from the received physical layer signals. Further, 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. Also, 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.

[0122] 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. Also, the setting unit 230 stores preset setting information. The content of the setting information is, for example, information related to the setting of D2D communication.

[0123] As described in the embodiments, the control unit 240 controls D2D communication for establishing an RRC connection with another terminal 20. Further, the control unit 240 performs processing related to power saving operations. 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 cooperation between terminals in D2D communication. A functional unit related to signal transmission in the control unit 240 may be included in the transmission unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the reception unit 220.

[0124] (Hardware Configuration) The block diagrams (FIGS. 20 and 21) 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.

[0125] The 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.

[0126] 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. 22 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.

[0127] 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.

[0128] 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.

[0129] The processor 1001 controls the entire computer by operating, for example, an operating system. 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, etc. For example, the above-described control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0130] Further, 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. 20 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. 21 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.

[0131] 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), and the like. The memory device 1002 may be referred to as a register, a cache, a main memory (main storage device), or the like. The memory device 1002 can store a program (program code), a software module, etc. that are executable for implementing the communication method according to an embodiment of the present disclosure.

[0132] 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 disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, and the like. 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.

[0133] 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 be configured to 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 duplexing (FDD) and time division duplexing (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 transmission section and a reception section.

[0134] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives an external input. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs an 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).

[0135] 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.

[0136] 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), and 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.

[0137] (Summary of Embodiment) As described above, according to the embodiment of the present invention, in a resource pool, a transmission unit that performs random selection of resources, a reception unit that receives control information from other terminals in a first period in the resource pool, and a control unit that performs re-evaluation or preemption check of the randomly selected resources based on the control information are provided.

[0138] With the above configuration, the probability of collision between the sidelink signal transmission of the terminal 20 that performs random selection in the sidelink and the sidelink signal transmission by other terminals 20 can be reduced. That is, in direct communication between terminals, the reliability of communication during autonomous resource selection can be improved.

[0139] The control unit may determine the start time of the first period based on the position of the time domain at the head of the second period in which resources are randomly selected or the position of the time domain of the randomly selected resources. With this configuration, the probability of collision between the sidelink signal transmission of the terminal 20 that performs random selection in the sidelink and the sidelink signal transmission by other terminals 20 can be reduced.

[0140] The control unit may determine the end point of the first period based on the position of the time region for executing re-evaluation or preemption and the processing time. With this configuration, it is possible to reduce the probability that the side link signal transmission of the terminal 20 that executes random selection in the side link collides with the side link signal transmission by another terminal 20.

[0141] The control unit may execute a check for re-evaluation or preemption based on the information related to resource reservation included in the control information and the candidates for resources that can be reserved by other terminals at the timing when the own device executes transmission. With this configuration, it is possible to reduce the probability that the side link signal transmission of the terminal 20 that executes random selection in the side link collides with the side link signal transmission by another terminal 20.

[0142] The control unit may use only the randomly selected resources as the identification target. With this configuration, it is possible to reduce the probability that the side link signal transmission of the terminal 20 that executes random selection in the side link collides with the side link signal transmission by another terminal 20.

[0143] Further, according to an embodiment of the present invention, there is provided a communication method in which a terminal executes a transmission procedure for randomly selecting a resource in a resource pool, a reception procedure for receiving control information from another terminal in a first period in the resource pool, and a control procedure for executing a check for re-evaluation or preemption of the randomly selected resource based on the control information.

[0144] With the above configuration, it is possible to reduce the probability that the side link signal transmission of the terminal 20 that executes random selection in the side link collides with the side link signal transmission by another terminal 20. That is, in direct communication between terminals, it is possible to improve the reliability of communication during autonomous resource selection.

[0145] (Supplement to the embodiment) The embodiments of the present invention have been described above. 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 the purpose of facilitating the understanding of the invention, unless otherwise specified, those numerical values are merely examples and any appropriate values may be used. The classification of the items in the above description is not essential to the present invention, and the matters described in two or more items may be used in combination as needed, or the matters described in one item may be applied to the matters described in another item (as long as there is no contradiction). The boundaries of the functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical components. The operations of a plurality of functional units may be physically performed by one component, or the operation of one functional unit may be physically performed by a plurality of 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. The software operating on the processor included in the base station 10 according to the embodiment of the present invention and the software operating on the processor included in the terminal 20 according to the embodiment of the present invention may be stored in a random access memory (RAM), a flash memory, a read-only memory (ROM), an EPROM, an EEPROM, a register, a hard disk drive (HDD), a removable disk, a CD-ROM, a database, a server, or any other appropriate storage medium, respectively.

[0146] 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 (RRC Connection Setup) message, an RRC connection reconfiguration (RRC Connection Reconfiguration) message, etc.

[0147] 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 on these. Also, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A and 5G, etc.) may be applied.

[0148] The processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this specification may be reordered as long as there is no contradiction. For example, for the methods described in the present disclosure, the elements of various steps are presented using an exemplary order and are not limited to the specific order presented.

[0149] The 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, it is clear that various operations performed for communication with the terminal 20 can 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, MME or 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, MME and S-GW).

[0150] The information or signals, etc. described in the present disclosure can be output from an upper layer (or lower layer) to a lower layer (or upper layer). They may also be input and output via a plurality of network nodes.

[0151] The input and output information, etc. may be stored in a specific location (for example, 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.

[0152] The determination in the present disclosure may be made based on a value represented by 1 bit (0 or 1), or may be made based on a Boolean value (true or false), or may be made based on a numerical comparison (for example, comparison with a predetermined value).

[0153] 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, a hardware description language, or by any other name.

[0154] 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 cables, fiber optic cables, twisted pairs, digital subscriber line (DSL)) and wireless technologies (such as infrared, microwave), at least one of these wired and wireless technologies is included within the definition of a transmission medium.

[0155] 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.

[0156] 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 referred to as a carrier frequency, a cell, a frequency carrier, etc.

[0157] The terms "system" and "network" as used in this disclosure are used interchangeably.

[0158] In addition, the information, parameters, etc. described in this disclosure may be represented using absolute values, relative values from a predetermined value, or using corresponding other information. For example, radio resources may be indicated by an index.

[0159] The names used for the above-described parameters are not limiting names in any way. Furthermore, the mathematical formulas, etc. 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 names, the various names assigned to these various channels and information elements are not limiting names in any way.

[0160] 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. The base station may also be called by terms such as macro cell, small cell, femto cell, pico cell, etc.

[0161] 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 the base station and the base station subsystem that provides communication services in this coverage.

[0162] In the present disclosure, terms such as "mobile station (MS)", "user terminal", "user equipment (UE)", and "terminal" can be used interchangeably.

[0163] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terms.

[0164] At least one of the base station and the mobile station may also be called a transmission device, a reception 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 unmanned (e.g., a drone, an autonomous vehicle, etc.), or a robot (humanoid or unmanned). 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.

[0165] 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 as functions of the terminal 20. Also, 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.

[0166] 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 as functions of the base station.

[0167] As used herein, the terms "determining" and "deciding" may encompass a wide 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 been "determined" or "decided" by performing some operation. Also, "determining (deciding)" may be read as "assuming", "expecting", "considering", etc.

[0168] The terms "connected" or "coupled," or any variation 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 may 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 electromagnetic energy having wavelengths in the radio frequency region, microwave region, and optical (both visible and invisible) regions, as some non-limiting and non-exhaustive examples.

[0169] The reference signal can also be abbreviated as RS (Reference Signal) and may be called a Pilot depending on the applicable standard.

[0170] 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."

[0171] 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.

[0172] The "means" in the configuration of each of the above devices may be replaced with "section," "circuit," "device," etc.

[0173] In the present disclosure, when terms such as "include", "including" and their variants are used, these terms are intended to be inclusive, similar to the term "comprising". Further, the term "or" used in the present disclosure is not intended to be an exclusive disjunction.

[0174] 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 called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) independent of numerology.

[0175] Numerology may be a communication parameter applied to at least one of transmission and reception of a certain signal or channel. Numerology may indicate at least one of, for example, 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.

[0176] A slot may be composed of one or more symbols (OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.) in the time domain. A slot may be a time unit based on numerology.

[0177] The slot may include a plurality of mini-slots. Each mini-slot may be composed of one or more symbols in the time domain. Also, the mini-slot may be called a sub-slot. The mini-slot may be composed of a smaller number of symbols than the slot. The PDSCH (or PUSCH) transmitted in a time unit larger than the mini-slot may be called PDSCH (or PUSCH) mapping type A. The PDSCH (or PUSCH) transmitted using the mini-slot may be called PDSCH (or PUSCH) mapping type B.

[0178] The radio frame, sub-frame, slot, mini-slot, and symbol all represent time units when transmitting signals. Different names corresponding to each of them may also be used.

[0179] For example, one sub-frame may be called a Transmission Time Interval (TTI), or a plurality of consecutive sub-frames may be called TTI, or one slot or one mini-slot may be called TTI. That is, at least one of the sub-frame and TTI may be the sub-frame (1 ms) in the existing LTE, or a period shorter than 1 ms (for example, 1 - 13 symbols), or a period longer than 1 ms. Note that the unit representing TTI may be called a slot, mini-slot, etc. instead of a sub-frame.

[0180] Here, TTI refers to, for example, the minimum time unit of scheduling in wireless communication. For example, in the LTE system, the base station performs scheduling to allocate radio resources (such as the frequency bandwidth and transmission power that can be used in each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0181] The TTI may be a transmission time unit such as a channel-coded 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.

[0182] 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-slot numbers) constituting the minimum time unit of the scheduling may be controlled.

[0183] 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 (partial or fractional TTI), a shortened subframe, a short subframe, a mini-slot, a sub-slot, a slot, etc.

[0184] Note that the long TTI (e.g., a normal TTI, a subframe, etc.) may be read as a TTI having a time length exceeding 1 ms, and the short TTI (e.g., a 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.

[0185] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and in the frequency domain, it may include one or a plurality of consecutive subcarriers. The number of subcarriers included in the RB may be the same regardless of the numerology, for example, it may be 12. The number of subcarriers included in the RB may be determined based on the numerology.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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 is defined in a certain BWP and may be numbered within the BWP.

[0190] 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.

[0191] 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".

[0192] The structures such as the above-mentioned 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 within a TTI, symbol length, cyclic prefix (CP) length, etc. can be variously changed.

[0193] In the present disclosure, for example, when articles are added by translation like a, an, and the in English, the present disclosure may include that the nouns following these articles are in the plural form.

[0194] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other". Note that the term may also mean "A and B are different from C respectively". Terms such as "separate", "coupled", etc. may also be interpreted in the same way as "different".

[0195] In the present disclosure, each aspect / embodiment described may be used alone, in combination, or switched for use 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, without performing the notification of the predetermined information).

[0196] Note that in the present disclosure, SCI is an example of control information. The sensing window is an example of the first period. The selection window is an example of the second period.

[0197] As described in detail above, 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 defined by the claims. Therefore, the description of the present disclosure is for illustrative purposes only and does not have any limiting meaning for the present disclosure.

Explanation of Signs

[0198] 10 Base station 110 Transmitter 120 Receiver 130 Setting unit 140 Control unit 20 Terminal 210 Transmitter 220 Receiver 230 Setting unit 240 Control unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims

1. In a resource pool, a transmission unit that performs random selection of resources, In the resource pool, a reception unit that receives control information from other terminals in a first period, A control unit that, based on the control information, performs re-evaluation or preemption check of the randomly selected resources, and The control unit determines the start time of the first period based on the position of the time region at the head of a second period in which resources are randomly selected or the position of the time region of the randomly selected resources. A terminal.

2. The terminal according to claim 1, wherein the control unit determines the end time of the first period based on the position of the time region for performing re-evaluation or preemption and the processing time.

3. The terminal according to claim 1, wherein the control unit performs a re-evaluation or preemption check based on information related to resource reservation included in the control information and candidates for resources that can be reserved by other terminals at the timing when the own device performs transmission.

4. The terminal according to claim 1, wherein the control unit targets only the randomly selected resources for identification.

5. In a resource pool, a transmission procedure for performing random selection of resources, In the resource pool, a reception procedure for receiving control information from other terminals in a first period, A control procedure for performing re-evaluation or preemption check of the randomly selected resources based on the control information, and A communication method in which a terminal executes a procedure for determining the start time of the first period based on the position of the time region at the head of a second period in which resources are randomly selected or the position of the time region of the randomly selected resources.

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