WO2022163159A1

WO2022163159A1 - Terminal and communication method

Info

Publication number: WO2022163159A1
Application number: PCT/JP2021/045302
Authority: WO
Inventors: 翔平吉岡; 聡永田
Original assignee: 株式会社Ｎｔｔドコモ
Priority date: 2021-01-29
Filing date: 2021-12-09
Publication date: 2022-08-04
Also published as: JP2024038533A

Abstract

This terminal comprises: a receiving unit for performing sensing in a resource pool; a transmitting unit for selecting, on the basis of a result of the sensing, a resource to be used for transmission; and a control unit for determining availability of the selected resource. If the control unit determines that the selected resource is not available, the transmitting unit again selects a resource on the basis of an operation related to resource selection that has already been performed.

Description

Terminal and communication method

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

LTE (Long Term Evolution) and successor systems of LTE (for example, LTE-A (LTE Advanced), NR (New Radio) (also referred to as 5G)), terminals communicate directly without a base station D2D (Device to Device) technology is being studied (for example, Non-Patent Document 1).

D2D reduces traffic between terminals and base stations, and enables communication between terminals even when base stations are unable to communicate due to disasters, etc. Note that the 3rd Generation Partnership Project (3GPP) refers to D2D as a "sidelink," but the more general term D2D is used herein. However, side links are also used as necessary in the description of the embodiments to be described later.

D2D communication includes D2D discovery (also referred to as D2D discovery) for discovering other terminals that can communicate, and D2D communication (D2D direct communication, D2D communication, direct communication between terminals) for direct communication between terminals. It is also called communication, etc.). Hereinafter, when D2D communication, D2D discovery, etc. are not particularly distinguished, they are simply referred to as D2D. A signal transmitted and received in D2D is called a D2D signal. Various use cases of services related to V2X (Vehicle to Everything) in NR are being considered (for example, Non-Patent Document 2).

Power saving is being considered as a way to strengthen the NR side link. For example, in resource allocation mode 2 in which the terminal autonomously selects resources, the terminal performs partial sensing for sensing limited resources within the sensing window, and Based on the results, select available resource candidates from the resource selection window.

For example, if the terminal detects that the selected resource cannot be used after performing resource selection by sensing, resource reselection may be performed. However, it is assumed that past slots corresponding to the timing of resource reselection are not monitored.

The present invention has been made in view of the above points, and aims to improve the efficiency of resource selection operations based on sensing during autonomous resource selection in direct communication between terminals.

According to the disclosed technology, in a resource pool, a receiving unit that performs sensing, a transmitting unit that selects a resource to be used for transmission based on the result of the sensing, and a control that determines whether the selected resource can be used. and a terminal in which, when the controller determines that the selected resource cannot be used, the transmitter reselects a resource based on an operation related to resource selection that has already been performed.

According to the disclosed technology, in direct communication between terminals, it is possible to improve the efficiency of resource selection operations based on sensing during autonomous resource selection.

It is a figure for demonstrating V2X. FIG. 2 is a diagram for explaining an example (1) of a V2X transmission mode; FIG. 3 is a diagram for explaining an example (2) of a V2X transmission mode; FIG. 10 is a diagram for explaining an example (3) of a V2X transmission mode; FIG. 11 is a diagram for explaining an example (4) of a V2X transmission mode; FIG. 11 is a diagram for explaining an example (5) of a V2X transmission mode; FIG. 2 is a diagram for explaining an example (1) of a V2X communication type; FIG. 3 is a diagram for explaining an example (2) of a V2X communication type; FIG. 10 is a diagram for explaining an example (3) of a V2X communication type; FIG. 4 is a sequence diagram showing an operation example (1) of V2X; FIG. 11 is a sequence diagram showing an operation example (2) of V2X; FIG. 11 is a sequence diagram showing an operation example (3) of V2X; FIG. 11 is a sequence diagram showing an operation example (4) of V2X; FIG. 10 is a diagram showing an example of sensing operation; 4 is a flowchart for explaining an example of preemption operation; FIG. 4 is a diagram showing an example of preemption operation; FIG. 10 is a diagram showing an example of partial sensing operation; FIG. 4 is a diagram for explaining an example of resource selection; 4 is a flow chart for explaining an example of communication in the embodiment of the invention; It is a figure showing an example of functional composition of base station 10 in an embodiment of the invention. 2 is a diagram showing an example of the functional configuration of terminal 20 according to the embodiment of the present invention; FIG. 2 is a diagram showing an example of hardware configuration of base station 10 or terminal 20 according to an embodiment of the present invention; FIG.

Embodiments of the present invention will be described below with reference to the drawings. In addition, the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

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

Further, in the embodiment of the present invention, the duplex system may be a TDD (Time Division Duplex) system, an FDD (Frequency Division Duplex) system, or other (for example, Flexible Duplex etc.) method may be used.

Further, in the embodiment of the present invention, "configuring" wireless parameters and the like may mean that predetermined values are preset (Pre-configure), and the base station 10 or A wireless parameter notified from the terminal 20 may be set.

FIG. 1 is a diagram for explaining V2X. In 3GPP, the realization of V2X (Vehicle to Everything) or eV2X (enhanced V2X) by extending the D2D function is under consideration, and specifications are being developed. As shown in Figure 1, V2X is a part of ITS (Intelligent Transport Systems), V2V (Vehicle to Vehicle), which means a form of communication between vehicles, roadside V2I (Vehicle to Infrastructure), which means a form of communication between a vehicle (RSU: Road-Side Unit), V2N (Vehicle to Network), which means a form of communication between a vehicle and an ITS server, and , is a generic term for V2P (Vehicle to Pedestrian), which means a form of communication between a vehicle and a mobile terminal carried by a pedestrian.

In addition, 3GPP is considering V2X using LTE or NR cellular communication and inter-terminal communication. V2X using cellular communication is also called cellular V2X. In NR's V2X, studies are underway to realize large capacity, low delay, high reliability, and QoS (Quality of Service) control.

It is expected that LTE or NR V2X will be considered in the future, not limited to 3GPP specifications. For example, ensuring interoperability, reducing costs by implementing upper layers, using multiple RATs (Radio Access Technology) together or switching methods, complying with regulations in each country, acquiring and distributing data from LTE or NR V2X platforms, managing databases, and It is assumed that usage methods will be considered.

In the embodiment of the present invention, it is mainly assumed that the communication device is mounted on a vehicle, but the embodiment of the present invention is 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, the communication device may be a base station, an RSU, a relay station (relay node), A terminal or the like having scheduling capability may be used.

Note that SL (Sidelink) may be distinguished based on either or a combination of UL (Uplink) or DL (Downlink) and 1) to 4) below. Also, SL may be another name.
1) Time domain resource allocation 2) Frequency domain resource allocation 3) Reference synchronization signal (including SLSS (Sidelink Synchronization Signal))
4) Reference signal used for path loss measurement for transmission power control

In addition, regarding SL or UL OFDM (Orthogonal Frequency Division Multiplexing), CP-OFDM (Cyclic-Prefix OFDM), DFT-S-OFDM (Discrete Fourier Transform-Spread-OFDM), OFDM without Transform precoding or Transform precoding Any of the OFDM methods available in the

In LTE SL, Mode 3 and Mode 4 are defined for SL resource allocation to terminals 20 . In Mode 3, transmission resources are dynamically allocated by DCI (Downlink Control Information) transmitted from the base station 10 to the terminal 20 . Mode 3 also allows SPS (Semi Persistent Scheduling). In Mode 4, the terminal 20 autonomously selects transmission resources from the resource pool.

A slot in the embodiment of the present invention may be read as a symbol, a mini-slot, a subframe, a radio frame, or a TTI (Transmission Time Interval). Also, the cell in the embodiment of the present invention may be read as cell group, carrier component, BWP, resource pool, resource, RAT (Radio Access Technology), system (including wireless LAN), and the like.

It should be noted 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 smart phone, or may be an IoT (Internet of Things) device such as a smart meter.

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

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

FIG. 4 is a diagram for explaining an example (3) of the V2X transmission mode. In the sidelink communication transmission mode shown in FIG. 4, in step 1, the terminal 20A uses the autonomously selected resource to transmit PSCCH and PSSCH to the terminal 20B. Similarly, terminal 20B uses the autonomously selected resource to transmit PSCCH and PSSCH to terminal 20A (step 1). The transmission mode of sidelink communication shown in FIG. 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.

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

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

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

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

FIG. 9 is a diagram for explaining an example (3) of the V2X communication type. The sidelink communication type shown in FIG. 9 is broadcast. Terminal 20A transmits PSCCH and PSSCH to one or more terminals 20 . In the example shown in FIG. 9, terminal 20A broadcasts to

terminals

20B, 20C and 20D. Note that the terminal 20A shown in FIGS. 7 to 9 may be called a header-UE.

Also, in NR-V2X, it is assumed that HARQ (Hybrid automatic repeat request) will be supported for sidelink unicast and groupcast. Furthermore, in NR-V2X, SFCI (Sidelink Feedback Control Information) including HARQ response is defined. Furthermore, transmission of the SFCI via a PSFCH (Physical Sidelink Feedback Channel) is being considered.

In the explanation below, the PSFCH is used for HARQ-ACK transmission on the sidelink, but this is just an example. For example, it may be to perform HARQ-ACK transmission on the sidelink using PSCCH, it may be to perform HARQ-ACK transmission on the sidelink using PSSCH, other channels It may be used to transmit HARQ-ACK on the sidelink.

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

FIG. 10 is a sequence diagram showing an operation example (1) of V2X. As shown in FIG. 10, the radio communication system according to the embodiment of the present invention may have terminal 20A and terminal 20B. Although there are actually many user devices, FIG. 10 shows the terminal 20A and the terminal 20B as an example.

Hereinafter, when the

terminals

20A, 20B, etc. are not particularly distinguished, they are simply referred to as "terminal 20" or "user device". Although FIG. 10 shows a case where both terminal 20A and terminal 20B are within the coverage of the cell as an example, the operation in the embodiment of the present invention can also be applied when terminal 20B is out of the coverage.

As described above, in the present embodiment, the terminal 20 is, for example, a device mounted in a vehicle such as an automobile, and has a cellular communication function as a UE in LTE or NR and a side link function. there is The terminal 20 may be a general mobile terminal (such as a smart phone). Also, the terminal 20 may be an RSU. The RSU may be a UE type RSU having UE functionality, or a gNB type RSU having base station apparatus functionality.

It should be noted that the terminal 20 does not have to be a device in one housing. For example, even if various sensors are distributed in the vehicle, the device including the various sensors may be the terminal 20 .

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 a codeword of transmission data, modulates it to generate complex-valued symbols, maps the complex-valued symbols (transmission signal) to one or two layers, and performs precoding. Then, the precoded complex-valued symbols are mapped to resource elements to generate a transmission signal (eg complex-valued time-domain SC-FDMA signal) and transmit from each antenna port.

Note that the base station 10 has a function of cellular communication as a base station in LTE or NR, and a function (eg, resource pool setting, resource allocation, etc.) for enabling communication of the terminal 20 in the present embodiment. have. Also, the base station 10 may be an RSU (gNB type RSU).

Further, 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. may be

In step S101, the terminal 20A autonomously selects resources to be used for PSCCH and PSSCH from a resource selection window having a predetermined period. A resource selection window may be set from the base station 10 to the terminal 20 . Here, with respect to 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 maximum allowable packet delay time, or the period may be defined in advance by the specifications, A predetermined period may be called an interval on the time domain.

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

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

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

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

Note that steps S104 and S105 may not be performed when HARQ control accompanied by HARQ feedback is not performed.

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

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

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

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

Note that step S204 may not be executed if blind retransmission is not executed.

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

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

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

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

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

Information on the resource is included in the DL scheduling DCI or SL scheduling DCI transmitted from the base station 10 in step S301, and the terminal 20A acquires the information on the resource from the DL scheduling DCI or SL scheduling DCI and transmits the SCI. include in Alternatively, the DCI transmitted from the base station 10 may not contain the information on the resource, and the terminal 20A may autonomously include the information on the resource in the SCI and transmit it.

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

In step S305, the terminal 20A, for example, at the timing (for example, slot unit timing) specified by the DL scheduling DCI (or the SL scheduling DCI), the PUCCH specified by the DL scheduling DCI (or the SL scheduling DCI) ( Physical uplink control channel) resource is used to transmit HARQ-ACK, and the base station 10 receives the HARQ-ACK. The HARQ-ACK codebook may include HARQ-ACKs generated based on HARQ-ACKs received from terminal 20B or PSFCHs not received, and HARQ-ACKs for DL data. However, HARQ-ACK for DL data is not included, such as when there is no DL data allocation. NR Rel. In 16, the HARQ-ACK codebook does not include HARQ-ACK for DL data.

Note that if HARQ control with HARQ feedback is not performed, step S304 and/or step S305 may not be performed.

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

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 one symbol at the beginning of the slot, may be arranged in a plurality of symbols from the beginning, or may be arranged in a plurality of symbols from symbols other than the beginning. The PSFCH may be arranged in one symbol at the end of the slot, or may be arranged in multiple symbols at the end of the slot. It should be noted that the above-mentioned "slot head" and "slot end" may omit consideration of symbols for AGC (Automatic Gain Control) and symbols for transmission/reception switching. That is, for example, when one slot consists of 14 symbols, the terms "slot head" and "slot end" refer to the symbols at the beginning and end of the 12 symbols excluding the symbols at the beginning and end, respectively. may In the example shown in FIG. 13, three subchannels are set in the resource pool, and two PSFCHs are arranged three slots after the slot in which the PSSCH is arranged. Arrows from PSSCH to PSFCH show examples of PSFCH associated with the PSSCH.

If the HARQ response in NR-V2X groupcast is groupcast option 2 that 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 terminal 20, performs a group cast to the

terminals

20B, 20C, and 20D, which are the receiving terminals 20, via SL-SCH. In subsequent step S402, terminal 20B uses PSFCH#B, terminal 20C uses PSFCH#C, and terminal 20D uses PSFCH#D to transmit a HARQ response to terminal 20A. Here, as shown in the example of FIG. 13, 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 be aware of the number of receiving terminals 20 in the group cast. Note that in groupcast option 1, only NACK is transmitted as the HARQ response, and ACK is not transmitted.

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

Also, as shown in FIG. 14, resource pool configuration may have a periodicity. For example, the period may be a period of 10240 milliseconds. FIG. 14 is an example in which slots from slot t ₀ ^SL to slot t _Tmax ^SL are set as a resource pool. The resource pool within each period may be defined by, for example, a bitmap.

Also, as shown in FIG. 14, it is assumed that the transmission trigger in terminal 20 occurs at slot n, and the priority of the transmission is p _TX . The terminal 20 can detect, for example, that another terminal 20 is transmitting with priority p _RX in the sensing window from slot nT ₀ to the slot immediately preceding slot _{nT proc,0} . . If SCI is detected within the sensing window and RSRP (Reference Signal Received Power) exceeds a threshold, 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 resource within the resource selection window corresponding to the SCI is not excluded. The thresholds may be, for example, thresholds Th _{pTX, pRX} that are set or defined for each resource within the sensing window based on the priority _pTX and the priority _pRX .

Also, resources within the resource selection window that are candidates for resource reservation information corresponding to resources within the sensing window that were not monitored, eg, for transmission, are excluded, such as slot t _m ^SL shown in FIG.

In the resource selection window from slot n+T ₁ to slot n+T ₂ , as shown in FIG. 14, resources occupied by other UEs are identified, and resources excluding those resources become available resource candidates. Let S _A be a set of available resource candidates, and if S _A is less than 20% of the resource selection window, the thresholds Th _{pTX and pRX} set for each resource in the sensing window are increased by 3 dB, and the resource selection is performed again. Identification may be performed. That is, by increasing the thresholds Th _{pTX and pRX} and executing resource identification again, the resources that are not excluded because the RSRP is less than the threshold are increased, and the set S _A of resource candidates reaches 20% or more of the resource selection window. You may make it If S _A is less than 20% of the resource selection window, the operation of increasing the thresholds Th _{pTX, pRX} set for each resource in the sensing window by 3 dB and performing resource identification again may be repeated.

The lower layers of terminal 20 may report the _SA to higher layers. Higher layers of terminal 20 may perform a random selection on _SA to determine which resource to use. The terminal 20 may perform sidelink transmission using the determined resource.

The operation of the transmitting terminal 20 has been described with reference to FIG. 14 above, but the receiving terminal 20 detects data transmission from another terminal 20 based on the result of sensing or partial sensing, and 20 may receive data.

FIG. 15 is a flow chart 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 predetermined limited period. Subsequently, the terminal 20 identifies each resource within the resource selection window based on the sensing result, determines a resource candidate set _SA , and selects resources to be used for transmission (S502). Subsequently, the terminal 20 selects a resource set (r_0, r_1, . . . ) for judging preemption from the resource candidate set _SA (S503). The resource set may be notified from the upper layer to the PHY layer as a resource for determining whether or not it has been preempted.

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 to determine the set S _A of resource candidates. , and determine preemption for resource sets (r_0, r_1, . . . ) based on priority. For example, in r_1 shown in FIG. 16, the SCI transmitted from the other terminal 20 is detected by re-sensing and is not included in _SA . When preemption is enabled, if the value prio_RX indicating the priority of the SCI transmitted from the other terminal 20 is lower than the value prio_TX indicating the priority of the transport block transmitted from the terminal 20, the terminal 20 uses the resource r_1. It is determined that preemption has occurred. Note that the lower the priority value, the higher the priority. That is, when the value prio_RX indicating the priority of the SCI transmitted from the other terminal 20 is higher than the value prio_TX indicating the priority of the transport block transmitted from the terminal 20, the terminal 20 does not exclude resource _{r_1} from SA. . Or, if preemption is valid only for a specific priority (for example, sl-PreemptionEnable is any of pl1, pl2, ..., pl8), let this priority be prio_pre. At this time, when the value prio_RX indicating the priority of the SCI transmitted from the other terminal 20 is lower than prio_pre and prio_RX is lower than the value prio_TX indicating the priority of the transport block transmitted from the own terminal, Terminal 20 determines that resource r_1 is preempted.

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

When re-evaluation is performed instead of checking preemption, in step S504, after determining the set S _A of resource candidates, the resource set (r_0, r_1, . . . ) is set to S _A. If the resource is not included, the resource is not used and the upper layer reselects the resource.

FIG. 17 is a diagram showing an example of partial sensing operation in NR. When partial sensing is set from the upper layer in the NR sidelink, the terminal 20 selects resources and performs transmission as shown in FIG. As shown in FIG. 17, the terminal 20 performs partial sensing on a part of the sensing window in the resource pool, that is, the sensing targets. With partial sensing, a terminal 20 receives resource reservation fields included in SCIs transmitted from other terminals 20, and based on the field, identifies available resource candidates within a resource selection window within a resource pool. . Subsequently, the terminal 20 randomly selects resources from available resource candidates.

FIG. 17 shows an example in which slots from slot t ₀ ^SL to slot t _Tmax-1 ^SL are set as a resource pool. A resource pool may have a target area set by, for example, a bitmap. As shown in FIG. 17, it is assumed that the transmission trigger at terminal 20 occurs at slot n. As shown in FIG. 17 , Y slots from slot t _y1 ^SL to slot t _yY ^SL in slot n+T ₁ to slot n+T ₂ may be set as the resource selection window.

The terminal 20 detects that, for example, another terminal 20 is transmitting at one or a plurality of sensing targets from the slot t _{y1−k×Pstep} ^SL to the slot t _{yY−k×Pstep} ^SL , which has a length of Y slots. can do. k may be determined by a 10-bit bitmap, for example. FIG. 17 shows an example in which the 3rd and 6th bits of the bitmap are set to "1" indicating that partial sensing is to be performed. That is, in FIG. 17, from slot t _y1-6×Pstep ^SL to slot t _yY-6×Pstep ^SL and from slot t _y1-3×Pstep ^SL to slot t _yY-3×Pstep ^SL are set as sensing targets. be done. As above, the kth bit of the bitmap may correspond to the sensing window from slot t _{y1−k×Pstep} ^SL to slot t _{yY−k×Pstep} ^SL . Note that _yi corresponds to the index (1...Y) in the Y slot.

Note that k may be set by a 10-bit bitmap or defined in advance, and P _step may be 100 ms. However, when performing SL communication with DL and UL carriers, P _step may be (U/(D+S+U))*100 ms. U corresponds to the number of UL slots, D to the number of DL slots, and S to the number of special slots.

If an SCI is detected in the sensing target above and the RSRP is above the threshold, the resource within the resource selection window corresponding to the resource reservation field of that SCI is excluded. Also, if an SCI is detected in the sensing target and the RSRP is less than the threshold, the resources within the resource selection window corresponding to the resource reservation field of the SCI are not excluded. The thresholds may be, for example, thresholds Th _{pTX, pRX} that are set or defined for each resource in the sensing target based on the transmitter priority p _TX and the receiver priority p _RX .

As shown in FIG. 17, terminal 20 identifies resources occupied by other UEs in a resource selection window in which slots are set in intervals [n+T ₁ , n+T ₂ ], and resources excluding those resources are Be a candidate for available resources. Note that the Y slots do not have to be consecutive. Let S _A be a set of available resource candidates, and if S _A is less than 20% of the resources in the resource selection window, the thresholds Th _{pTX, pRX} set for each resource of the sensing target are increased by 3 dB and again Resource identification may be performed.

That is, by increasing the thresholds Th _{pTX and pRX} and identifying the resources again, the resources that are not excluded because the RSRP is less than the thresholds may be increased. Further, the RSSI of each resource in S _A may be measured and the resource with the lowest RSSI may be added to the set S _B . The operation of adding the resource with the smallest RSSI included in S _A to S _B may be repeated until the set S _B of resource candidates is equal to or greater than 20% of the resource selection window.

The lower layers of terminal 20 may report the _SB to higher layers. Higher layers in terminal 20 may perform a random selection on S _B to determine which resource to use. The terminal 20 may perform sidelink transmission using the determined resource. Note that the terminal 20 may periodically use the resource without performing sensing for a predetermined number of times (for example, C _resel times) after securing the resource once.

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

In addition, eURLLC (enhanced Ultra Reliable Low Latency Communication) is being considered in the NR Release 17 sidelink, with inter-UE coordination as the baseline. For example, terminal 20A may share information indicating resource sets with terminal 20B, and terminal 20B may consider this information in resource selection for transmission.

For example, the terminal 20 may perform full sensing as shown in FIG. 14 as a resource allocation method in the sidelink. Also, the terminal 20 may perform partial sensing in which resource identification is performed by sensing only limited resources compared to full sensing, and resource selection is performed from the identified resource set. In addition, the terminal 20 sets the resource within the resource selection window as the identified resource set without excluding the resource from the resources within the resource selection window, and performs random selection for selecting the resource from the identified resource set. You may

A method of performing random selection at the time of resource selection and using sensing information at the time of re-evaluation or preemption check may be treated as partial sensing or random selection.

In Release 17, the operation may be defined by assuming two types of terminals 20. One is type A, where type A terminals 20 do not have the ability to receive any sidelink signals and channels. However, receiving PSFCH and S-SSB may be an exception.

The other is type D, where type D terminals 20 have the ability to receive all sidelink signals and channels defined in Release 16. However, it does not preclude receiving some sidelink signals and channels.

Note that UE types other than type A and type B above may be assumed, and UE types and UE capabilities may or may not be associated.

Also, in Release 17, multiple resource allocation methods can be set for a given resource pool. Also, SL-DRX (Discontinuous reception) is supported as one of the power saving functions. That is, the receiving operation is performed only during a predetermined time interval.

Here, it is assumed that re-evaluation or preemption check is performed after resources are selected by partial sensing. If re-evaluation or pre-emption checks detect or determine that the selected resource cannot be used, resource re-selection may be performed.

FIG. 18 is a diagram for explaining an example of resource selection. As shown in FIG. 18, when the sensing slot for resource selection and the sensing slot for resource reselection do not match, the terminal 20 does not monitor past slots corresponding to the timing of resource reselection. is assumed. Therefore, it takes a long time to apply operations similar to resource selection to resource reselection, increasing the delay. On the other hand, if the sensing slots for resource reselection are monitored in advance, power consumption increases.

Therefore, a resource selection method that achieves low latency and low power consumption is required. It should be noted that instead of re-evaluation or preemption checking of the selected resource, congestion control may be used to detect or determine that the selected resource is unusable.

FIG. 19 is a flow chart for explaining an example of communication according to the embodiment of the present invention. In step S601, the terminal 20 performs resource selection using sensing information. In subsequent step S602, the terminal 20 determines whether or not use of the selected resource has been stopped. If the use of the selected resource has been stopped (YES in S602), or if the use of the selected resource has not been stopped (NO in S602), the flow ends. In step S603, the terminal 20 executes a predetermined resource selection operation. The sensing in step S601 may be partial sensing or full sensing. It should be noted that whether or not the resource selected in step S602 can be used may be determined, and if the terminal 20 determines that the resource cannot be used, the terminal 20 may stop using the resource.

Discontinuation of the selected resource in step S602 may be based on any of re-evaluation, preemption check or congestion control, but is not limited to these. That is, in step S602, the terminal 20 may perform re-evaluation, preemption check or congestion control on the selected resource. The mechanism of resource selection using sensing information in step S601 may be limited to periodic resource reservation based on the resource reservation period field. Also, the execution of the operation shown in FIG. 19 may be limited to the case where the transmission of the own device is periodic transmission. The case where the transmission of the own device is periodic transmission may be, for example, the case where a resource reservation interval (resource reservation interval) P_rsvp_TX>0 is notified from an upper layer.

Further, in step S602, if the use of Y resources satisfying 0<Y<X among the selected X resources is stopped, at least one of the XY resources is used, and the terminal 20 No need to perform resource reselection.

Further, the operation related to predetermined resource selection in step S603 may be resource reselection that is executed based on information related to resource allocation at the time of resource selection. For example, terminal 20 may perform resource reselection based on the resource set identified during resource selection. For example, the terminal 20 may reselect resources from resources later than the resource reselection timing among the resource sets identified at the time of resource selection. For example, among the candidate resources at the time of executing resource selection, the terminal 20 may target the resources included in the interval [k+T ₁ , t_Y], where t_Y is the last slot and k is the resource reselection timing. . For example, the terminal 20 limits resource candidates to be selected based on the sensing information used for resource selection (for example, resources included in the interval [k+T ₁ , t_Y]), performs resource identification again, and performs resource identification. resource set may be reselected. _The above T1 may be T1, which is the time from the slot _n at which resource selection is executed to the start slot of the resource selection window.

Further, the operation related to predetermined resource selection in step S603 may be resource reselection performed based on information related to resource allocation at the time of re-evaluation or preemption check. For example, terminal 20 may perform resource reselection based on resource sets identified during re-evaluation or preemption checks. For example, the terminal 20 may reselect resources from resources later than the resource reselection timing among the identified resource sets at the time of re-evaluation or preemption check. For example, among the resources identified during re-evaluation or preemption check execution, the terminal 20 selects resources included in the section [k+T ₁ , t_Y], where t_Y is the last slot and k is the resource reselection timing. It may be a target. For example, the terminal 20 limits resource candidates to be selected based on the sensing information used for re-evaluation or preemption check (for example, resources included in the section [k+T ₁ , t_Y]), and performs resource identification again. , may reselect resources from the identified resource set. _The above T1 may be T1, which is the processing time from the slot _n at which resource selection is executed to the start slot of the resource selection window.

Further, the operation related to the predetermined resource selection in step S603 may be resource reselection based on the sensing information by performing additional sensing from the timing related to resource selection to the timing of resource reselection. The timing related to the resource selection may be any of 1) to 5) shown below.

1) Timing at which resource selection is triggered 2) Timing of resource selection 3) Candidate slots for selecting resources 4) Processing time (e.g., T _proc,0 , T _proc,1 , T ₃ , etc.)
5) Combination of above 1)-4)

Note that T _proc,0 may be the processing time from the last slot of the sensing window to resource selection. T _proc,1 may be the upper limit of T ₁ above. T3 may be the processing time from the beginning of the resource selection window at the time of re _- evaluation or preemption check to the timing of re-evaluation or preemption check.

In addition, the operation related to the predetermined resource selection in step S603 includes performing resource identification again based on the additional sensing information in addition to the various parameters and sensing information used at the time of resource selection, and identifying the identified resource set. It may be an operation of reselecting the resource from.

In addition, the operation related to predetermined resource selection in step S603 performs additional sensing from the timing related to re-evaluation or preemption check to the timing of resource re-selection, even if it is resource re-selection based on the sensing information good. The timing for resource selection may be any of 1) to 5) shown below.

1) Timing when re-evaluation or preemption check is triggered 2) Timing of re-evaluation or pre-emption check 3) Slot for which resource is identified in re-evaluation or preemption check 4) Processing time (e.g. T _proc,0 , T _{proc, 1} , T3 _, etc.)
5) Combination of above 1)-4)

In addition, the operation related to the predetermined resource selection in step S603 performs resource identification again based on the additional sensing information in addition to the various parameters and sensing information used at the time of re-evaluation or preemption check, and is identified. It may be an operation of reselecting a resource from the set of resources that have been selected.

Also, the operation related to predetermined resource selection in step S603 may be resource reselection by a resource allocation mechanism different from the resource allocation mechanism at the time of resource selection. That is, the terminal 20 may change the resource allocation mechanism during resource selection and perform resource reselection.

For example, the operation related to predetermined resource selection in step S603 may be resource reselection by random selection that does not use sensing information.

For example, the operation related to predetermined resource selection in step S603 performs sensing for a predetermined period from the timing related to resource reselection, performs resource identification based on the sensing information, and reselects resources from the identified resource set. You may choose. For example, the timing for resource reselection may be any of 1) to 6) shown below.

1) Timing at which resource reselection is triggered 2) Timing of resource reselection 3) Candidate slots for resource reselection 4) Processing time (e.g., T _proc,0 , T _proc,1 , T ₃ , 1 slot, etc.) )
5) Sensing slot 6) Combination of above 1)-5)

The predetermined period of time for sensing may be determined based on any of 1) to 6) shown below.

1) Candidate slots for resource reselection 2) Processing time (e.g., T _proc,0 , T _proc,1 , T ₃ , 1 slot, etc.)
3) Transmission priority 4) Past HARQ feedback information 5) Remaining PDB (Packet delay budget)
6) Combination of above 1)-5)

For example, in the operation related to predetermined resource selection in step S603, when resource reselection is performed by changing the resource allocation mechanism at the time of resource selection, subsequent resource selection, resource reselection, The operations related to re-evaluation and preemption may apply the changed resource allocation mechanism, may apply the resource allocation mechanism before the change, or may apply another resource allocation mechanism.

It should be noted that the above embodiment may be applied to the operation of one terminal 20 setting or allocating transmission resources for another terminal 20 . That is, resource configuration or allocation may be performed such that the above embodiments are satisfied.

The above embodiments are not limited to V2X terminals, and may be applied to terminals that perform D2D communication.

　The operations according to the above embodiment may be executed only in a specific resource pool. For example, it may be executed only in resource pools that terminals 20 of release 17 or later can use.

According to the above-described embodiment, when the terminal 20 detects that the selected resource cannot be used, the terminal 20 can efficiently Resources can be reselected.

That is, in direct communication between terminals, the efficiency of resource selection operations based on sensing during autonomous resource selection can be improved.

(Device configuration)
Next, functional configuration examples of the base station 10 and the terminal 20 that execute the processes and operations described above will be described. The base stations 10 and terminals 20 contain the functionality to implement the embodiments described above. However, each of the base station 10 and terminal 20 may have only part of the functions in the embodiment.

<Base station 10>
FIG. 20 is a diagram showing an example of the functional configuration of the base station 10. As shown in FIG. As shown in FIG. 20, the base station 10 has a transmitting section 110, a receiving section 120, a setting section 130, and a control section 140. The functional configuration shown in FIG. 20 is merely an example. As long as the operation according to the embodiment of the present invention can be executed, the functional division and the names of the functional units may be arbitrary.

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 receiving unit 120 includes a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, higher layer information from the received signals. Also, the transmitting 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 .

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

The control unit 140 performs processing related to setting for the terminal 20 to perform D2D communication, as described in the embodiment. Also, the control unit 140 transmits scheduling of D2D communication and DL communication to the terminal 20 via the transmission unit 110 . Also, the control unit 140 receives information related to HARQ responses for D2D communication and DL communication from the terminal 20 via the receiving unit 120 . A functional unit related to signal transmission in control unit 140 may be included in transmitting unit 110 , and a functional unit related to signal reception in control unit 140 may be included in receiving unit 120 .

<Terminal 20>
FIG. 21 is a diagram showing an example of the functional configuration of the terminal 20. As shown in FIG. As shown in FIG. 21, the terminal 20 has a transmitting section 210, a receiving section 220, a setting section 230, and a control section 240. The functional configuration shown in FIG. 21 is merely an example. As long as the operation according to the embodiment of the present invention can be executed, the functional division and the names of the functional units may be arbitrary.

The transmission unit 210 creates a transmission signal from the transmission data and wirelessly transmits the transmission signal. The receiving unit 220 wirelessly receives various signals and acquires a higher layer signal from the received physical layer signal. The receiving unit 220 also 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, as D2D communication, to the other terminal 20, PSCCH (Physical Sidelink Control Channel), PSSCH (Physical Sidelink Shared Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel) etc., and the receiving unit 220 receives PSCCH, PSSCH, PSDCH, PSBCH, or the like from other terminals 20 .

The setting unit 230 stores various setting information received from the base station 10 or the terminal 20 by the receiving unit 220 in the storage device, and reads them from the storage device as necessary. The setting unit 230 also stores preset setting information. The content of the setting information is, for example, information related to setting of D2D communication.

The control unit 240 controls D2D communication that establishes an RRC connection with another terminal 20, as described in the embodiment. In addition, the control unit 240 performs processing related to power saving operation. In addition, the control unit 240 performs processing related to HARQ for D2D communication and DL communication. Also, the control unit 240 transmits to the base station 10 information related to HARQ responses of D2D communication and DL communication scheduled from the base station 10 to other terminals 20 . The control unit 240 may also schedule D2D communication for other terminals 20 . In addition, the control unit 240 may autonomously select resources to be used for D2D communication from a resource selection window based on sensing results, or may perform re-evaluation or preemption. In addition, the control unit 240 performs processing related to power saving in transmission and reception of D2D communication. In addition, the control unit 240 performs processing related to inter-terminal cooperation in D2D communication. A functional unit related to signal transmission in control unit 240 may be included in transmitting unit 210 , and a functional unit related to signal reception in control unit 240 may be included in receiving unit 220 .

(Hardware configuration)
The block diagrams (FIGS. 20 and 21) used to describe the above embodiments show blocks in functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Also, the method of implementing each functional block is not particularly limited. That is, each functional block may be implemented using one device that is physically or logically coupled, or directly or indirectly using two or more devices that are physically or logically separated (e.g. , wired, wireless, etc.) and may be implemented using these multiple devices. A functional block may be implemented by combining software in the one device or the plurality of devices.

Functions include judging, determining, determining, calculating, calculating, processing, deriving, investigating, searching, checking, receiving, transmitting, outputting, accessing, resolving, selecting, choosing, establishing, comparing, assuming, expecting, assuming, Broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc. can't For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. In either case, as described above, the implementation method is not particularly limited.

For example, the base station 10, the terminal 20, etc. according to the embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. FIG. 22 is a diagram illustrating an example of a hardware configuration of base station 10 and terminal 20 according to an embodiment of the present disclosure. The base station 10 and terminal 20 described above are physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like. good too.

In the following explanation, the term "apparatus" can be read as a circuit, device, unit, or the like. The hardware configuration of the base station 10 and terminal 20 may be configured to include one or more of each device shown in the figure, or may be configured without some devices.

Each function of the base station 10 and the terminal 20 is performed by the processor 1001 performing calculations and controlling communication by the communication device 1004 by loading predetermined software (programs) onto hardware such as the processor 1001 and the storage device 1002. or by controlling at least one of data reading and writing in the storage device 1002 and the auxiliary storage device 1003 .

The processor 1001, for example, operates an operating system and controls the entire computer. The processor 1001 may be configured with a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, registers, and the like. For example, the control unit 140 , the control unit 240 and the like described above may be implemented by the processor 1001 .

In addition, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 to the storage device 1002, and executes various processes according to them. As the program, a program that causes a computer to execute at least part of the operations described in the above embodiments is used. For example, control unit 140 of base station 10 shown in FIG. 20 may be implemented by a control program stored in storage device 1002 and operated by processor 1001 . Also, for example, the control unit 240 of the terminal 20 shown in FIG. 21 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001 . Although it has been explained that the above-described various processes are executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. FIG. Processor 1001 may be implemented by one or more chips. Note that the program may be transmitted from a network via an electric communication line.

The storage device 1002 is a computer-readable recording medium, for example, ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. may be configured. The storage device 1002 may also be called a register, cache, main memory (main storage device), or the like. The storage device 1002 can store executable programs (program code), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

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

The communication device 1004 is hardware (transmitting/receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also called a network device, a network controller, a network card, a communication module, or the like. The communication device 1004 includes a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., in order to realize at least one of, for example, frequency division duplex (FDD) and time division duplex (TDD). may consist of For example, a transmitting/receiving antenna, an amplifier section, a transmitting/receiving section, a transmission line interface, etc. may be implemented by the communication device 1004 . The transceiver may be physically or logically separate implementations for the transmitter and receiver.

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

Each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between devices.

In addition, the base station 10 and the terminal 20 include hardware such as microprocessors, digital signal processors (DSPs), ASICs (Application Specific Integrated Circuits), PLDs (Programmable Logic Devices), and FPGAs (Field Programmable Gate Arrays). , and part or all of each functional block may be implemented by the hardware. For example, processor 1001 may be implemented using at least one of these pieces of hardware.

(Summary of embodiment)
As described above, according to the embodiments of the present invention, in a resource pool, a receiving unit that performs sensing, a transmitting unit that selects resources to be used for transmission based on the result of the sensing, and a control unit that determines whether or not the selected resource can be used, and if the control unit determines that the selected resource cannot be used, the transmission unit selects the resource based on an operation related to resource selection that has already been performed. A reselecting terminal is provided.

With the above configuration, when the terminal 20 detects that the selected resource cannot be used, the terminal 20 uses part of the information when the resource is selected and the information when the re-evaluation or preemption check is performed, thereby efficiently using the resource. can be reselected. That is, in inter-terminal direct communication, it is possible to improve the efficiency of resource selection operations based on sensing during autonomous resource selection.

The receiving unit may perform partial sensing, and the transmitting unit may select resources to be used for transmission based on the result of the partial sensing. With this configuration, when the terminal 20 detects that the selected resource cannot be used by partial sensing, the terminal 20 uses part of the information when the resource is selected and the information when the re-evaluation or preemption check is performed. resources can be reselected.

The already executed operation related to resource selection may be a re-evaluation or preemption check executed by the control unit on the selected resource. With this configuration, when the terminal 20 detects that the selected resource cannot be used, the terminal 20 uses part of the information at the time of resource selection and the information at the time of re-evaluation or preemption check to efficiently use the resource. Can be reselected.

The transmitting unit may reselect resources based on a resource set identified in a re-evaluation or preemption check performed by the control unit on the selected resources. With this configuration, when the terminal 20 detects that the selected resource cannot be used, the terminal 20 uses part of the information at the time of resource selection and the information at the time of re-evaluation or preemption check to efficiently use the resource. Can be reselected.

The transmitting unit may reselect resources from a resource set identified in a re-evaluation or preemption check performed on the selected resources by the control unit. With this configuration, when the terminal 20 detects that the selected resource cannot be used, the terminal 20 uses part of the information at the time of resource selection and the information at the time of re-evaluation or preemption check to efficiently use the resource. Can be reselected.

Further, according to the embodiment of the present invention, in a resource pool, a reception procedure for performing sensing, a transmission procedure for selecting resources to be used for transmission based on the results of the sensing, and use of the selected resources Provided is a communication method in which a terminal executes a control procedure for determining availability, and a procedure for reselecting a resource based on an operation related to already executed resource selection when it is determined that the selected resource cannot be used. .

(Supplement to the embodiment)
Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art can understand various modifications, modifications, alternatives, replacements, and the like. be. Although specific numerical examples have been used to facilitate understanding of the invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. The division of items in the above description is not essential to the present invention, and the items described in two or more items may be used in combination as necessary, and the items described in one item may be used in another item. may apply (unless inconsistent) to the matters set forth in Boundaries of functional or processing units in functional block diagrams do not necessarily correspond to boundaries of physical components. The operations of a plurality of functional units may be physically performed by one component, or the operations of one functional unit may be physically performed by a plurality of components. As for the processing procedures described in the embodiments, the processing order may be changed as long as there is no contradiction. Although the base station 10 and the terminal 20 have been described using functional block diagrams for convenience of explanation of processing, such devices may be implemented in hardware, software, or a combination thereof. The software operated by the processor of the base station 10 according to the embodiment of the present invention and the software operated by the processor of the terminal 20 according to the embodiment of the present invention are stored in random access memory (RAM), flash memory, read-only memory, respectively. (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or any other appropriate storage medium.

Also, notification of information is not limited to the aspects/embodiments described in the present disclosure, and may be performed using other methods. For example, notification of information includes physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, It may be implemented by broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or a combination thereof.In addition, RRC signaling may also be called an RRC message, for example, RRC It may be a connection setup (RRC Connection Setup) message, an RRC connection reconfiguration message, or the like.

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

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

A specific operation performed by the base station 10 in this specification may be performed by its upper node in some cases. In a network consisting of one or more network nodes with base station 10, various operations performed for communication with terminal 20 may be performed by base station 10 and other network nodes other than base station 10 ( (eg, but not limited to MME or S-GW). Although the case where there is one network node other than the base station 10 is illustrated above, the other network node may be a combination of a plurality of other network nodes (for example, MME and S-GW). .

Information, signals, etc. described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer). It may be input and output via multiple network nodes.

Input/output information may be stored in a specific location (for example, memory) or managed using a management table. Input/output information and the like can be overwritten, updated, or appended. The output information and the like may be deleted. The entered information and the like may be transmitted to another device.

The determination in the present disclosure may be performed by a value represented by 1 bit (0 or 1), may be performed by a boolean value (Boolean: true or false), or may be performed by comparing numerical values (e.g. , comparison with a predetermined value).

Software, whether referred to as software, firmware, middleware, microcode, hardware description language or otherwise, includes instructions, instruction sets, code, code segments, program code, programs, subprograms, and software modules. , applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, and the like.

In addition, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, the software uses at least one of wired technology (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technology (infrared, microwave, etc.) to website, Wired and/or wireless technologies are included within the definition of transmission medium when sent from a server or other remote source.

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

The terms explained in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, the channel and/or symbols may be signaling. A signal may also be a message. A component carrier (CC) may also be called a carrier frequency, a cell, a frequency carrier, or the like.

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

In addition, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values from a predetermined value, or may be expressed using other corresponding information. may be represented. For example, radio resources may be indexed.

The names used for the parameters described above are not restrictive names in any respect. Further, the formulas, etc., using these parameters may differ from those expressly disclosed in this disclosure. Since the 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 in no way restrictive names. is not.

In the present disclosure, "base station (BS)", "radio base station", "base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB ( gNB)", "access point", "transmission point", "reception point", "transmission/reception point", "cell", "sector", " Terms such as "cell group", "carrier", "component carrier" may be used interchangeably. A base station may also be referred to by terms such as macrocell, small cell, femtocell, picocell, and the like.

A base station can accommodate one or more (eg, three) cells. When a base station accommodates multiple cells, the overall coverage area of the base station can be partitioned into multiple smaller areas, each smaller area being associated with a base station subsystem (e.g., an indoor small base station (RRH: The term "cell" or "sector" refers to part or all of the coverage area of at least one of the base stations and base station subsystems serving communication in this coverage. point to

In the present disclosure, terms such as "Mobile Station (MS)", "user terminal", "User Equipment (UE)", "terminal", etc. may be used interchangeably. .

A mobile station is defined 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 It may also be called a terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term.

At least one of the base station and mobile station may be called a transmitting device, a receiving device, a communication device, or the like. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, or the like. The mobile object may be a vehicle (e.g., car, airplane, etc.), an unmanned mobile object (e.g., drone, self-driving car, etc.), or a robot (manned or unmanned ). Note that at least one of the base station and the mobile station includes devices that do not necessarily move during communication operations. For example, at least one of the base station and mobile station may be an IoT (Internet of Things) device such as a sensor.

Also, the base station in the present disclosure may be read as a user terminal. For example, communication between a base station and a user terminal is replaced with communication between a plurality of terminals 20 (for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.) Regarding the configuration, each aspect/embodiment of the present disclosure may be applied. In this case, the terminal 20 may have the functions of the base station 10 described above. Also, words such as "up" and "down" may be replaced with words corresponding to inter-terminal communication (for example, "side"). For example, uplink channels, downlink channels, etc. may be read as side channels.

Similarly, user terminals in the present disclosure may be read as base stations. In this case, the base station may have the functions that the above-described user terminal has.

The terms "determining" and "determining" used in this disclosure may encompass a wide variety of actions. "Judgement" and "determination" are, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (eg, lookup in a table, database, or other data structure), ascertaining as "judged" or "determined", and the like. Also, "judgment" and "determination" are used for receiving (e.g., receiving information), transmitting (e.g., transmitting information), input, output, access (accessing) (for example, accessing data in memory) may include deeming that a "judgment" or "decision" has been made. In addition, "judgment" and "decision" are considered to be "judgment" and "decision" by resolving, selecting, choosing, establishing, comparing, etc. can contain. In other words, "judgment" and "decision" may include considering that some action is "judgment" and "decision". Also, "judgment (decision)" may be read as "assuming", "expecting", "considering", or the like.

The terms "connected", "coupled", or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, It can include the presence of one or more intermediate elements between two elements being "connected" or "coupled." Couplings or connections between elements may be physical, logical, or a combination thereof. For example, "connection" may be read as "access". As used in this disclosure, two elements are defined using at least one of one or more wires, cables, and printed electrical connections and, as some non-limiting and non-exhaustive examples, in the radio frequency domain. , electromagnetic energy having wavelengths in the microwave and optical (both visible and invisible) regions, and the like.

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

The term "based on" as used in this disclosure does not mean "based only on" unless otherwise specified. In other words, the phrase "based on" means both "based only on" and "based at least on."

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

"Means" in the configuration of each device described above may be replaced with "unit", "circuit", "device", or the like.

Where "include," "including," and variations thereof are used in this disclosure, these terms are inclusive, as is the term "comprising." is intended. Furthermore, the term "or" as used in this disclosure is not intended to be an exclusive OR.

A radio frame may consist of one or more frames in the time domain. Each frame or frames in the time domain may be referred to as a subframe. A subframe may also consist of one or more slots in the time domain. A subframe may be of a fixed length of time (eg, 1 ms) independent of numerology.

A numerology may be a communication parameter that applies to the transmission and/or reception of a signal or channel. Numerology, for example, subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, transceiver It may indicate at least one of certain filtering operations performed in the frequency domain, certain windowing operations performed by the transceiver in the time domain, and/or the like.

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

A slot may contain multiple mini-slots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be referred to as a subslot. A minislot may consist of fewer symbols than a slot. PDSCH (or PUSCH) transmitted in time units larger than minislots may be referred to as PDSCH (or PUSCH) mapping type A. PDSCH (or PUSCH) transmitted using minislots may be referred to as PDSCH (or PUSCH) mapping type B.

Radio frames, subframes, slots, minislots and symbols all represent time units when transmitting signals. Radio frames, subframes, slots, minislots and symbols may be referred to by other corresponding designations.

For example, one subframe may be called a Transmission Time Interval (TTI), a plurality of consecutive subframes may be called a TTI, and one slot or one minislot may be called a TTI. may That is, at least one of the subframe and TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (eg, 1-13 symbols), or a period longer than 1 ms may be Note that the unit representing the TTI may be called a slot, mini-slot, or the like instead of a subframe.

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

A TTI may be a transmission time unit such as a channel-encoded data packet (transport block), code block, or codeword, or may be a processing unit such as scheduling and link adaptation. Note that when a TTI is given, the time interval (for example, the number of symbols) in which transport blocks, code blocks, codewords, etc. are actually mapped may be shorter than the TTI.

When one slot or one minislot is called a TTI, one or more TTIs (that is, one or more slots or one or more minislots) may be the minimum scheduling time unit. Also, the number of slots (the number of mini-slots) constituting the minimum time unit of the scheduling may be controlled.

A TTI having a time length of 1 ms may be called a normal TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, normal subframe, normal subframe, long subframe, slot, or the like. A TTI that is shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a minislot, a subslot, a slot, and the like.

Note that the long TTI (e.g., normal TTI, subframe, etc.) may be replaced with a TTI having a time length exceeding 1 ms, and the short TTI (e.g., shortened TTI, etc.) is less than the TTI length of the long TTI and 1 ms A TTI having the above TTI length may be read instead.

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

Also, the time domain of an RB may include one or more symbols and may be 1 slot, 1 minislot, 1 subframe, or 1 TTI long. One TTI, one subframe, etc. may each consist of one or more resource blocks.

One or more RBs are physical resource blocks (PRBs), sub-carrier groups (SCGs), resource element groups (REGs), PRB pairs, RB pairs, etc. may be called.

Also, a resource block may be composed of one or more resource elements (RE: Resource Element). For example, 1 RE may be a radio resource region of 1 subcarrier and 1 symbol.

A bandwidth part (BWP) (which may also be called a bandwidth part) may represent a subset of contiguous common resource blocks (RBs) for a certain numerology on a certain carrier. Here, the common RB may be identified by an RB index based on the common reference point of the carrier. PRBs may be defined in a BWP and numbered within that BWP.

The BWP may include a BWP for UL (UL BWP) and a BWP for DL (DL BWP). One or more BWPs may be configured for terminal 20 within one carrier.

At least one of the configured BWPs may be active, and the terminal 20 may not expect to transmit or receive a given signal/channel outside the active BWP. Note that "cell", "carrier", etc. in the present disclosure may be read as "BWP".

The structures such as radio frames, subframes, slots, minislots and symbols described above are only examples. For example, the number of subframes contained in a radio frame, the number of slots per subframe or radio frame, the number of minislots contained within a slot, the number of symbols and RBs contained in a slot or minislot, the number of Configurations such as the number of subcarriers, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. can be varied.

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

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

Each aspect/embodiment described in the present disclosure may be used alone, may be used in combination, or may be used by switching along with execution. In addition, the notification of predetermined information (for example, notification of “being X”) is not limited to being performed explicitly, but may be performed implicitly (for example, not notifying the predetermined information). good too.

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be practiced with modifications and variations without departing from the spirit and scope of the present disclosure as defined by the claims. Accordingly, the description of the present disclosure is for illustrative purposes and is not meant to be limiting in any way.

This international patent application claims priority based on Japanese Patent Application No. 2021-013788 filed on January 29, 2021, and the entire contents of Japanese Patent Application No. 2021-013788 are included in this application. invoke.

10 base station 110 transmitting unit 120 receiving unit 130 setting unit 140 control unit 20 terminal 210 transmitting unit 220 receiving unit 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

a receiver that performs sensing in the resource pool;
a transmission unit that selects a resource to be used for transmission based on the sensing result;
a control unit that determines whether the selected resource can be used;
A terminal in which, when the control unit determines that the selected resource cannot be used, the transmission unit reselects the resource based on an operation related to resource selection that has already been performed.
The terminal according to claim 1, wherein the receiving unit performs partial sensing, and the transmitting unit selects resources to be used for transmission based on the result of the partial sensing.
The terminal according to claim 2, wherein the already executed operation related to resource selection is a re-evaluation or preemption check executed by the control unit on the selected resource.
The terminal according to claim 3, wherein the transmission unit reselects resources based on a resource set identified in a re-evaluation or preemption check performed on the selected resources by the control unit.
The terminal according to claim 4, wherein the transmission unit reselects resources from a resource set identified in a re-evaluation or preemption check performed on the selected resources by the control unit.
a receiving procedure for performing sensing in a resource pool;
a transmission procedure for selecting resources to be used for transmission based on the sensing result;
a control procedure for determining availability of the selected resource;
and a communication method in which, when it is determined that the selected resource cannot be used, a procedure for reselecting the resource based on the already executed operation related to resource selection is performed by the terminal.