WO2024089779A1

WO2024089779A1 - Terminal and communication method

Info

Publication number: WO2024089779A1
Application number: PCT/JP2022/039782
Authority: WO
Inventors: 翔平吉岡; 太一七條; 聡永田
Original assignee: 株式会社Ｎｔｔドコモ
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2024-05-02

Abstract

A terminal comprising a control unit that determines a time point for starting certain transmission in a unlicensed band, the time point being a start or an intermediate of a section set for inter-terminal direct communication in a unit time, a reception unit that executes the listen before talk (LBT) in an LBT channel for the transmission, and a transmission unit that starts, when the LBT is successful, the transmission to another terminal at the determined time point, wherein the control unit changes a signal for the transmission when the transmission is to be started at the intermediate of the section.

Description

Terminal and communication method

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

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

D2D reduces traffic between terminals and base stations, and enables communication between terminals even if the base station becomes unable to communicate due to a disaster or other reason. In addition, 3GPP (registered trademark) (3rd Generation Partnership Project) refers to D2D as "sidelink," but in this specification, the more general term D2D is used. However, in the explanation of the embodiments described later, sidelink will also be used as necessary.

D2D communication is broadly divided into D2D discovery (also called D2D discovery) for discovering other terminals with which it can communicate, and D2D communication (also called D2D direct communication, D2D communication, direct communication between terminals, etc.) for direct communication between terminals. In the following, when there is no particular distinction between D2D communication, D2D discovery, etc., it will simply be referred to as D2D. Furthermore, signals transmitted and received in D2D will be referred to as D2D signals. Various use cases for services related to V2X (Vehicle to Everything) in NR are being considered (for example, Non-Patent Document 2).

In addition, in NR Release 17 (e.g., Non-Patent Document 3), the use of higher frequency bands than in previous releases is being considered. For example, applicable numerology including subcarrier spacing and channel bandwidth in the frequency band from 52.6 GHz to 71 GHz, physical layer design, and anticipated interference in actual wireless communications are being considered.

Unlicensed bands are defined for new frequency bands that use higher frequencies than conventional ones. Various regulations are defined for unlicensed bands, for example, LBT (Listen before talk) is executed when accessing a channel. When performing D2D communication in these high frequency bands, operation that complies with the regulations in unlicensed bands is required. Here, in order to improve resource utilization efficiency when LBT fails, if channel transmission in direct communication between terminals can be started at multiple points within a unit time, the method of channel transmission was unclear.

The present invention has been made in consideration of the above points, and aims to perform channel transmission for direct communication between terminals that complies with regulations in unlicensed bands.

According to the disclosed technology, a terminal is provided that has a control unit that determines whether a transmission in an unlicensed band should be started from the beginning of a section set for direct communication between terminals in a unit time or from the middle of the section, a receiving unit that performs LBT (Listen before talk) on an LBT channel for the transmission, and a transmitting unit that starts the transmission to another terminal from the determined time if the LBT is successful, and the control unit changes the signal of the transmission when the transmission is started from the middle of the section.

The disclosed technology makes it possible to perform channel transmission for direct terminal-to-terminal communication that complies with regulations in unlicensed bands.

FIG. 1 is a diagram for explaining V2X. FIG. 1 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. 11 is a diagram illustrating an example of a sensing operation. 11 is a flowchart illustrating an example of a preemption operation. FIG. 13 illustrates an example of a preemption operation. FIG. 13 is a diagram illustrating an example of a partial sensing operation. FIG. 13 is a diagram for explaining an example of periodic partial sensing. FIG. 13 is a diagram for explaining an example of continuous partial sensing. FIG. 4 is a diagram illustrating an example of a frequency range according to an embodiment of the present invention. FIG. 1 is a diagram for explaining an example of LBT (1). FIG. 13 is a diagram for explaining an example of LBT (2). FIG. 13 is a diagram for explaining an example of LBT (3). FIG. 1 is a diagram for explaining an example (1) of channel transmission in an embodiment of the present invention. FIG. 11 is a diagram for explaining an example (2) of channel transmission in an embodiment of the present invention. FIG. 11 is a diagram for explaining an example (3) of channel transmission in an embodiment of the present invention. FIG. 11 is a diagram for explaining an example (4) of channel transmission in an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a functional configuration of a base station 10 according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal 20 according to an embodiment of the present invention. 2 is a diagram illustrating an example of a hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the configuration of a vehicle 2001 according to an embodiment of the present invention.

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

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

Furthermore, in an embodiment of the present invention, the duplex method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or another method (e.g., Flexible Duplex, etc.).

In addition, in the embodiment of the present invention, when radio parameters and the like are "configured," this may mean that predetermined values are pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are configured.

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

3GPP is also considering V2X using LTE or NR cellular and terminal-to-terminal communications. V2X using cellular communications is also called cellular V2X. For NR V2X, studies are underway to achieve high capacity, low latency, high reliability, and QoS (Quality of Service) control.

It is expected that future studies on LTE or NR V2X will be conducted beyond 3GPP specifications. For example, it is expected that studies will be conducted on ensuring interoperability, reducing costs by implementing higher layers, methods for using or switching between multiple RATs (Radio Access Technologies), compliance with regulations in each country, and methods for acquiring, distributing, managing databases, and using data on LTE or NR V2X platforms.

In the embodiment of the present invention, the communication device is mainly assumed to be 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 with scheduling capability, etc.

In addition, SL (Sidelink) may be distinguished as UL (Uplink) or DL (Downlink) based on any one or combination of 1) to 4) below. SL may also be called by other names.
1) Resource allocation in the time domain; 2) Resource allocation in the frequency domain; 3) Reference synchronization signal (including SLSS (Sidelink Synchronization Signal))
4) Reference signal used for path loss measurement for transmission power control

Furthermore, with regard to SL or UL OFDM (Orthogonal Frequency Division Multiplexing), either CP-OFDM (Cyclic-Prefix OFDM), DFT-S-OFDM (Discrete Fourier Transform - Spread - OFDM), OFDM without transform precoding or OFDM with transform precoding may be applied.

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

Note that the slot in the embodiments of the present invention may be interpreted as a symbol, minislot, subframe, radio frame, or TTI (Transmission Time Interval). Furthermore, a slot is an example of a unit of time, and may be replaced with a term indicating a different unit of time. Furthermore, a cell in the embodiments of the present invention may be interpreted as a cell group, carrier component, BWP, resource pool, resource, RAT (Radio Access Technology), system (including wireless LAN), etc.

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

In addition, it is expected that NR-SL will support HARQ (Hybrid automatic repeat request) for sidelink unicast and groupcast. Furthermore, NR-V2X will define SFCI (Sidelink Feedback Control Information) that includes HARQ responses. It is also being considered to transmit SFCI via PSFCH (Physical Sidelink Feedback Channel).

In the following description, the PSFCH is used to transmit the HARQ-ACK on the sidelink, but this is just one example. For example, the PSCCH may be used to transmit the HARQ-ACK on the sidelink, the PSSCH may be used to transmit the HARQ-ACK on the sidelink, or another channel may be used to transmit the HARQ-ACK on the sidelink.

For the sake of convenience, in the following, all 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, etc. is referred to as the HARQ-ACK codebook. The HARQ-ACK codebook specifies the bit string of the HARQ-ACK information. Note that in addition to ACK, NACK is also transmitted by "HARQ-ACK".

FIG. 2 is a sequence diagram showing an example (1) of V2X operation. As shown in FIG. 2, a wireless communication system according to an embodiment of the present invention may have terminal 20A and terminal 20B. Note that, although in reality, many user devices exist, FIG. 2 shows terminal 20A and terminal 20B as an example.

Hereinafter, when there is no particular distinction between

terminals

20A, 20B, etc., they will be simply referred to as "terminal 20" or "user device." In FIG. 2, as an example, a case is shown in which

terminals

20A and 20B are both within the coverage of a cell, but the operation in the embodiment of the present invention can also be applied to a case in which terminal 20B is outside the coverage.

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

In addition, the terminal 20 does not have to be a device in a single housing. For example, even if various sensors are distributed throughout the vehicle, the device including the various sensors may be the terminal 20.

Furthermore, the processing of sidelink transmission data by terminal 20 is basically the same as the processing of UL transmission in LTE or NR. For example, terminal 20 scrambles and modulates the codeword of the transmission data to generate complex-valued symbols, maps the complex-valued symbols (transmission signal) to one or two layers, and performs precoding. Then, it maps the precoded complex-valued symbols to resource elements to generate a transmission signal (e.g., a complex-valued time-domain SC-FDMA signal), which is then transmitted from each antenna port.

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

Furthermore, 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 another signal waveform.

As a synchronization signal in SL, the terminal 20 transmits a Sidelink Synchronization Signal Block (S-SSB). The S-SSB may include the Sidelink Primary Synchronization Signal (S-PSS), the Sidelink Secondary Synchronization Signal (S-SSS), and the Physical Sidelink Broadcast Channel (PSBCH). Note that the names S-SSB, S-PSS, S-SSS, etc. are merely examples, and names other than S-SSB, S-PSS, S-SSS, etc. may also be used.

The terminal 20 transmits an S-SSB to another terminal 20 based on a signal received from the base station device 10, a Global Navigation Satellite System (GNSS) signal, or a signal received from another terminal 20. If the terminal 20 cannot transmit an S-SSB based on any signal from the base station device 10, the GNSS, or another terminal 20, the terminal 20 may transmit an autonomously determined S-SSB to the other terminal 20. The resources available for the S-SSB may be periodic slots and may be referred to as S-SSB opportunities.

In step S101, 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 in the terminal 20 by the base station 10. Here, the predetermined period of the resource selection window may be determined by the implementation conditions of the terminal, such as the processing time or the maximum allowable packet delay time, or may be determined in advance by the specifications, or the predetermined period may be called an interval in the time domain.

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

Terminal 20B receives the SCI (PSCCH and/or PSSCH) and SL data (PSSCH) transmitted from terminal 20A. The received SCI may include information on the PSFCH resource for terminal 20B to transmit a HARQ-ACK in response to the reception of the data. Terminal 20A may transmit information on autonomously selected resources by including it in the SCI. Note that the resources available for the PSFCH may be periodic slots and the last symbols in the slot (excluding the final symbol), and may be called PSFCH opportunities.

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

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

Note that if HARQ control involving HARQ feedback is not performed, steps S104 and S105 do not need to be performed.

FIG. 3 is a sequence diagram showing an example of V2X operation (2). Blind retransmission without HARQ control may be performed to improve the transmission success rate or reach.

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 in the terminal 20 by the base station 10.

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

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

Note that if blind retransmission is not performed, step S204 does not need to be performed.

FIG. 4 is a sequence diagram showing an example (3) of V2X operation. The base station 10 may perform sidelink scheduling. 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 involving HARQ feedback is applied, the base station 10 may transmit information indicating the PSFCH resources to the terminal 20.

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

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

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

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

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

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

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

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

Figure 5 is a sequence diagram showing an example of V2X operation (4). As described above, in the NR sidelink, it is supported that the HARQ response is transmitted on the PSFCH. The format of the PSFCH can be, for example, a format similar to PUCCH (Physical Uplink Control Channel) format 0. 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 differences in sequence and/or cyclic shift. The format of the PSFCH is not limited to this. The PSFCH resource may be placed in the last symbol or the last multiple symbols of the slot. In addition, a period N is set or predefined for the PSFCH resource. The period N may be set or predefined on a slot-by-slot basis.

In FIG. 5, the vertical axis corresponds to the frequency domain, and the horizontal axis corresponds to the time domain. The PSCCH may be placed in one symbol at the beginning of the slot, or in multiple symbols from the beginning, or in multiple symbols from a symbol other than the beginning. The PSFCH may be placed in one symbol at the end of the slot, or in multiple symbols at the end of the slot. Note that the above-mentioned "beginning of the slot" and "end of the slot" may omit consideration of symbols for AGC (Automatic Gain Control) and symbols for transmission/reception switching. That is, for example, when one slot is composed of 14 symbols, the "beginning of the slot" and "end of the slot" may mean the first and last symbols, respectively, of the 12 symbols excluding the first and last symbols. In the example shown in FIG. 5, three subchannels are set in the resource pool, and two PSFCHs are placed three slots after the slot in which the PSSCH is placed. The arrow from the PSSCH to the PSFCH shows an example of a PSFCH associated with the PSSCH.

If the HARQ response in NR-V2X group cast is group cast option 2, which transmits ACK or NACK, it is necessary to determine the resources to be used for transmitting and receiving the PSFCH. As shown in FIG. 5, in step S401, terminal 20A, which is the transmitting terminal 20, performs group cast to

terminals

20B, 20C, and 20D, which are receiving terminals 20, via SL-SCH (Sidelink Shared Channel). In the following step S402, terminal 20B uses PSFCH#B, terminal 20C uses PSFCH#C, and terminal 20D uses PSFCH#D to transmit the HARQ response to terminal 20A. Here, as shown in the example of FIG. 5, if 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. In addition, with groupcast option 1, only NACK is sent as the HARQ response, and ACK is not sent.

Figure 6 is a diagram showing an example of sensing operation in NR. In resource allocation mode 2, the terminal 20 selects a resource and transmits. As shown in Figure 6, the terminal 20 performs sensing in a sensing window in a resource pool. By sensing, the terminal 20 receives a resource reservation field or a resource assignment field included in an SCI transmitted from another terminal 20, and identifies available resource candidates in a resource selection window in the resource pool based on the field. The terminal 20 then randomly selects a resource from the available resource candidates.

Also, as shown in Fig. 6, the resource pool may be set to a period. For example, the period may be a period of 10240 milliseconds. Fig. 6 shows an example in which slot t ₀ ^SL to slot t _Tmax-1 ^SL are set as a resource pool. The resource pool in each period may have an area set by, for example, a bitmap.

Also, as shown in FIG. 6, it is assumed that a transmission trigger in the terminal 20 occurs in 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 n-T ₀ to the slot immediately before slot n-T _proc,0 . When SCI is detected in the sensing window and the Reference Signal Received Power (RSRP) exceeds a threshold, the resource in the resource selection window corresponding to the SCI is excluded. Also, when SCI is detected in the sensing window and the RSRP is less than a threshold, the resource in the resource selection window corresponding to the SCI is not excluded. The threshold may be, for example, a threshold Th _{pTX,pRX that} is set or defined for each resource in the sensing window based on the priority p _TX and the priority p _RX .

Also, resources in the resource selection window that are candidates for resource reservation information corresponding to resources in the sensing window that were not monitored, for example for transmission, such as slot t _m ^SL shown in FIG. 6, are excluded.

In the resource selection window from slot n+ _T1 to slot n+ _T2 , as shown in FIG. 6, resources occupied by other UEs are identified, and the resources from which the resources are excluded become available resource candidates. If the set of available resource candidates is S _A , when S _A is less than 20% of the resource selection window, the threshold value Th _pTX,pRX set for each resource of the sensing window may be increased by 3 dB and resource identification may be performed again. That is, by increasing the threshold value Th _pTX,pRX and performing resource identification again, the number of resources that are not excluded because the RSRP is less than the threshold value may be increased so that the set of resource candidates S _A becomes 20% or more of the resource selection window. When S _A is less than 20% of the resource selection window, the operation of increasing the threshold value Th _pTX,pRX set for each resource of the sensing window by 3 dB and performing resource identification again may be repeated.

The lower layer of the terminal 20 may report S _A to the upper layer. The upper layer of the terminal 20 may perform random selection on S _A to determine the resources to be used. The terminal 20 may perform sidelink transmission using the determined resources. For example, the upper layer may be a MAC layer, and the lower layer may be a PHY layer or a physical layer.

In FIG. 6 above, the operation of the sending terminal 20 is described, but the receiving terminal 20 may detect data transmission from another terminal 20 based on the results of sensing or partial sensing, and receive data from the other terminal 20.

FIG. 7 is a flowchart showing an example of preemption in NR. FIG. 8 is a diagram showing an example of preemption in NR. In step S501, the terminal 20 performs sensing in a sensing window. When the terminal 20 performs a power saving operation, sensing may be performed in a predefined limited period. Next, the terminal 20 identifies each resource in the resource selection window based on the sensing result to determine a set S _A of resource candidates and selects resources to be used for transmission (S502). Next, the terminal 20 selects a resource set (r_0, r_1, ...) for determining preemption from the set S _A of resource candidates (S503). The resource set may be notified to the PHY layer from the upper layer as a resource for determining whether or not preemption has been performed.

In step S504, the terminal 20 re-identifies each resource in the resource selection window based on the sensing result at the timing of T(r_0) _-T3 shown in FIG. 8 to determine a set of resource candidates S _A , and further determines preemption for the resource set (r_0, r_1, ...) based on the priority. For example, r_1 shown in FIG. 8 is not included in S _A because the SCI transmitted from the other terminal 20 has been detected by re-sensing. 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 itself, the terminal 20 determines that the resource r_1 has been preempted. Note that the lower the value indicating the priority, the higher the priority. 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 itself, the terminal 20 does not exclude the resource r_1 from the _SA . Alternatively, when preemption is valid only for a specific priority (for example, sl-PreemptionEnable is any of pl1, pl2, ..., pl8), this priority is set as 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 terminal itself, the terminal 20 determines that the resource r_1 has been preempted.

In step S505, if 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.

In addition, when performing re-evaluation instead of checking preemption, after determining the set S _A of resource candidates in step S504, if a resource in the resource set (r_0, r_1, ...) is not included in S _A , the resource is not used and a resource re-selection is performed in the upper layer.

FIG. 9 is a diagram showing an example of partial sensing operation in LTE. When partial sensing is configured from a higher layer in the LTE side link, the terminal 20 selects resources and transmits as shown in FIG. 9. As shown in FIG. 9, the terminal 20 performs partial sensing on a part of a sensing window in a resource pool, i.e., a sensing target. With partial sensing, the terminal 20 receives a resource reservation field included in an SCI transmitted from another terminal 20, and identifies available resource candidates in a resource selection window in the resource pool based on the field. The terminal 20 then randomly selects a resource from the available resource candidates.

Fig. 9 shows an example in which subframe t ₀ ^SL to subframe t _Tmax-1 ^SL are set as a resource pool. The target area of the resource pool may be set by, for example, a bitmap. As shown in Fig. 9, a transmission trigger in terminal 20 is assumed to occur in subframe n. As shown in Fig. 9, among subframes n+T ₁ to n+T ₂ , Y subframes from subframe t _y1 ^SL to subframe t _yY ^SL may be set as a resource selection window.

The terminal 20 can detect, for example, that another terminal 20 is transmitting in one or more sensing targets from subframe t _y1-k×Pstep ^SL to subframe t _yY-k×Pstep ^SL , which has a Y subframe length. k may be determined by, for example, a 10-bit bitmap. FIG. 9 shows an example in which the third and sixth bits of the bitmap are set to "1" indicating that partial sensing is performed. That is, in FIG. 9, subframe t _y1-6×Pstep ^SL to subframe t _yY-6×Pstep ^SL and subframe t _y1-3×Pstep ^SL to subframe t _yY-3×Pstep ^SL are set as sensing targets. As described above, the kth bit of the bitmap may correspond to a sensing window from subframe t _y1-k×Pstep ^SL to subframe t _yY-k×Pstep ^SL . Note that _yi corresponds to index (1...Y) in the Y subframe.

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

When SCI is detected in the sensing target and the RSRP is greater than a threshold, the resource in the resource selection window corresponding to the resource reservation field of the SCI is excluded. Also, when SCI is detected in the sensing target and the RSRP is less than a threshold, the resource in the resource selection window corresponding to the resource reservation field of the SCI is not excluded. The threshold may be, for example, a threshold Th _{pTX,pRX that} is set or defined for each resource in the sensing target based on the sender priority p _TX and the receiver priority p _RX .

As shown in Fig. 9, in a resource selection window set in the Y subframe of the section [n+ _T1 , n+ _T2 ], the terminal 20 identifies resources occupied by other UEs, and the resources excluding the identified resources become available resource candidates. Note that the Y subframe does not have to be consecutive. If the set of available resource candidates is S _A , when S _A is less than 20% of the resources in the resource selection window, the threshold Th _pTX,pRX set for each sensing target resource may be increased by 3 dB and resource identification may be performed again.

That is, the threshold Th _pTX,pRX may be increased and resource identification may be performed again to increase the number of resources that are not excluded because their RSRP is below the threshold. Furthermore, the RSSI of each resource in S _A may be measured, and the resource with the smallest 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 becomes 20% or more of the resource selection window.

The lower layer of the terminal 20 may report S _B to the upper layer. The upper layer of the terminal 20 may perform random selection on S _B to determine the resource to be used. The terminal 20 may perform sidelink transmission using the determined resource. After reserving the resource once, the terminal 20 may use the resource periodically without performing sensing for a predetermined number of times (e.g., C _resel times).

In the NR sidelink, power saving based on random resource selection and partial sensing is specified. A terminal 20 to which partial sensing is applied performs reception and sensing only in specific slots within the sensing window. That is, the terminal 20 may perform resource identification by sensing only limited resources compared to full sensing, and perform partial sensing to select resources from the identified resource set. The terminal 20 may also perform random selection to select resources from the identified resource set by setting the resources in the resource selection window as the identified resource set without excluding resources from the resources in the resource selection window.

Note that the method of performing random selection at the time of resource selection and using sensing information during reevaluation or preemption checks may be treated as partial sensing or as random selection.

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

1) Periodic-based partial sensing
In a mechanism in which sensing is performed only on some slots, an operation of determining a sensing slot based on a reservation periodicity. Note that the reservation period is a value related to a resource reservation period field. Note that the period may be replaced with periodicity.

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

Furthermore, multiple resource allocation methods can be set for a given resource pool. Also, SL-DRX (Discontinuous reception) is supported as a power saving function. In other words, reception operations are only performed during a specified time period.

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

10 is a diagram for explaining an example of periodic partial sensing. As shown in FIG 10, Y candidate slots for resource selection are selected from a resource selection window [n+T ₁ , n+T ₂ ].

Sensing may be performed by regarding t _y ^SL as one slot included in the Y candidate slots and t _{y−k×Preserve} ^SL as a target slot for periodic partial sensing.

_Preserve may correspond to all values included in a set or predefined set sl-ResourceReservePeriodList. Alternatively, values of _Preserve limited to a subset of sl-ResourceReservePeriodList may be set or predefined. _Preserve and sl-ResourceReservePeriodList may be set for each transmission resource pool of resource allocation mode 2. Furthermore, as a UE implementation, a period included in sl-ResourceReservePeriodList other than the limited subset may be monitored. For example, the terminal 20 may additionally monitor an opportunity corresponding to P_RSVP_Tx.

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

As described above, partial sensing is supported as one of the power saving functions. In a resource pool in which partial sensing is configured, the terminal 20 may execute the above-mentioned continuous partial sensing. The terminal 20 may receive information from the base station 10 for configuring a resource pool in which partial sensing is configured and non-periodic reservations are enabled.

Fig. 11 is a diagram for explaining an example of continuous partial sensing. As shown in Fig. 11, when the trigger for resource selection is slot n, the terminal 20 selects Y candidate slots for resource selection from the resource selection window [n+ _T1 , n+ _T2 ]. Fig. 11 shows an example in which Y=7. As shown in Fig. 11, the head of the Y candidate slots is represented as slot t _y1 , the next slot as t _y2 , ..., and the end of the Y candidate slots as slot t _yY .

The terminal 20 performs sensing in the interval [n+T _A , n+T _B ], and executes resource selection at n+T _B or after n+T _B (n+T _C ). The above-mentioned periodic partial sensing may be additionally executed. Note that T _A and T _B in the interval [n+T _A , n+T _B ] may be any value. Also, n may be replaced with the index of any slot among the Y candidate slots.

In addition, the symbol [ may be replaced with the symbol (, and the symbol ] may be replaced with the symbol). For example, the interval [a, b] is the interval from slot a to slot b, including slot a and slot b. For example, the interval (a, b) is the interval from slot a to slot b, not including slot a and slot b.

Candidate resources to be selected are referred to as Y candidate slots, but all slots in the interval [n+T ₁ , n+T ₂ ] may be candidate slots, or only some of the slots may be candidate slots.

Furthermore, inter-terminal coordination has been specified as a method for improving reliability and delay performance. For example, the inter-terminal coordination method 1 and inter-terminal coordination method 2 shown below have been specified. In the following, the terminal 20 that transmits coordination information will be referred to as UE-A, and the terminal 20 that receives the coordination information will be referred to as UE-B.

Inter-UE coordination method 1) For transmission by UE-B, a preferred resource set and/or a non-preferred resource set is transmitted from UE-A to UE-B. Hereinafter, inter-UE coordination method 1 is also referred to as IUC scheme 1 (Inter-UE coordination scheme 1).

Inter-UE coordination method 2) UE-A transmits to UE-B information indicating resources in which collision with other transmissions or receptions is expected and/or collisions have been detected, among resources indicated by the SCI received from UE-B. The information may be transmitted via the PSFCH. Hereinafter, inter-UE coordination method 2 is also referred to as IUC scheme 2 (Inter-UE coordination scheme 2).

3GPP Release 16 or Release 17 sidelink is specified for 1) and 2) below.

1) An environment in which only 3GPP terminals exist in the ITS (Intelligent Transport Systems) band. 2) An environment in which UL resources are available for SL in the licensed bands of FR1 (Frequency range 1) and FR2 defined by NR.

Unlicensed bands are being considered for inclusion as side links in 3GPP Release 18 and beyond. For example, unlicensed bands such as the 5GHz-7GHz band and the 60GHz band.

Figure 12 is a diagram showing an example of frequency bands used in wireless communication systems. In the NR specifications of 3GPP Release 15 and Release 16, it is being considered to operate in frequency bands of, for example, 52.6 GHz or higher. As shown in Figure 12, FR (Frequency range) 1, which is currently specified for operation, is the frequency band from 410 MHz to 7.125 GHz, SCS (Sub carrier spacing) is 15, 30 or 60 kHz, and the bandwidth is from 5 MHz to 100 MHz.

FR2-1 is a frequency band from 24.25 GHz to 52.6 GHz, and the SCS uses 60, 120 or 240 kHz, with a bandwidth of 50 MHz to 400 MHz. As shown in Figure 12, FR2-2 may be assumed to be from 52.6 GHz to 71 GHz. It may also be assumed to support frequency bands above 71 GHz.

When using bands above 52.6 GHz, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM)/Discrete Fourier Transform - Spread (DFT-S-OFDM) with larger Sub-Carrier Spacing (SCS) may be applied.

Also, in high frequency bands such as FR2-2, increased phase noise between carriers becomes an issue. This may necessitate the application of a larger (wider) SCS or single carrier waveform.

For example, examples of unlicensed bands in the 5 GHz-7 GHz band include 5.15 GHz to 5.35 GHz, 5.47 GHz to 5.725 GHz, and 5.925 GHz and above.

For example, examples of unlicensed bands in the 60 GHz band include 59 GHz to 66 GHz, 57 GHz to 64 GHz or 66 GHz, and 59.4 GHz to 62.9 GHz.

In unlicensed bands, various regulations are in place to prevent interference with other systems or devices.

For example, in the 5 GHz-7 GHz band, LBT (Listen before talk) is executed when accessing the channel. The base station 10 or terminal 20 performs power detection for a specified period immediately before transmitting, and if the power exceeds a certain value, i.e. if it detects transmission from another device, it stops transmission (this may be called LBT failure). In addition, a maximum channel occupancy time (MCOT) is specified. MCOT is the maximum time period during which continued transmission is permitted when transmission is started after LBT, and is, for example, 4 ms in Japan.

Furthermore, the Occupied channel bandwidth (OCB) requirement states that when a transmission uses a certain carrier bandwidth, it must use at least X% of that bandwidth. For example, in Europe, it is required to use 80% to 100% of the nominal channel bandwidth (NCB). The OCB requirement is intended to ensure that power detection for channel access is performed correctly.

Furthermore, with regard to maximum transmission power and maximum power spectral density, in order to avoid excessive interference, it is stipulated that transmissions must be performed at or below a certain transmission power. For example, in Europe, the maximum transmission power is 23 dBm in the 5150 MHz-5350 MHz band. Also, for example, in Europe, the maximum power spectral density is 10 dBm/MHz in the 5150 MHz-5350 MHz band.

For example, in the 60 GHz band, LBT is performed when accessing a channel. The base station 10 or terminal 20 performs power detection for a specified period immediately before transmitting, and if the power exceeds a certain value, i.e. if transmission from another device is detected, the transmission is halted. In addition, with regard to maximum transmission power and maximum power spectral density, it is specified that transmission is performed at or below a specified transmission power. It is also specified that the terminal has the capability to satisfy OCB requirements.

In NR, the following four types of channel access procedures are defined based on the difference in the time behavior of LBT (the period during which sensing is performed). Note that this sensing is a different operation from the sidelink sensing described above, and is described as LBT sensing to distinguish it.

Type 1) Variable time LBT sensing is performed before transmission. Also called Category 4 LBT.
Type 2A) Performs 25 μs LBT sensing before transmission. Also known as Category 2 LBT.
Type 2B) Performs 16 μs LBT sensing before transmission. Also called Category 2 LBT.
Type 2C) Start transmission without LBT. Same as licensed band transmission.

Figure 13 is a diagram for explaining an example of LBT (1). Figure 13 is an example of a type 1 channel access procedure. Type 1 is further classified into four classes indicating channel access priority classes (CAPC) based on differences in LBT sensing length. LBT sensing is performed in the following two periods.

The first period is a prioritization period or a defer duration, and has a length of 16+9×m _p [μs], where m _p is a fixed value defined for each channel access priority class.

The second period is a backoff procedure, and has a length of 9 x N [μs]. The value of N is determined randomly from a certain range (see the CWS adjustment procedure in Non-Patent Document 4). N is the initial value of the backoff counter, and the value of the backoff counter is decreased by 1 each time the power of a signal from another device is not detected within 9 [μs].

In the above, the 9 μs LBT sensing period may be referred to as the LBT sensing slot period.

In the example of Fig. 13, m _p = 3, and the hold period is 43 μs. As shown in Fig. 13, the backoff counter is fixed while the channel is busy. Also, as shown in Fig. 13, when the transmissions of the NR-U gNB and the wireless LAN node #2 collide and an error is detected, the contention window size (CWS) is expanded from 3 to 13 in the NR-U gNB.

Figure 14 is a diagram for explaining an example of LBT (2). Figure 14 is an example of a channel access procedure of Type 2A or Type 2B without random backoff. A power detection gap of 25 μs or more is set before transmission for Type 2A, and a power detection gap of 16 μs is set for Type 2B.

FIG. 15 is a diagram for explaining an example of LBT (3). FIG. 15 is an example of a type 2C channel access procedure. As shown in FIG. 15, no power detection is performed before transmission, and the transmission is performed immediately after a gap not exceeding 16 μs. The transmission period may be up to 584 μs.

As described above, multiple LBT types are supported in NR-U. In the above type 1, the initial value N of the backoff counter is set to a random number in the interval from 0 to CW _p , whose value range is determined based on the channel access priority class p. Table 1 shows examples of m _p , the minimum value CW p,min of CW _p , and the maximum value CW _p , _max of CW _p , which are specified for each channel access priority class p in the UL.

As shown in Table 1, m _p , CW _p,min , and CW _p,max are determined by the channel access priority class p. When p is 1, the LBT period calculated from Table 1 is a minimum of 34 μs and a maximum of 88 μs. When p is 2, the LBT period calculated from Table 1 is a minimum of 34 μs and a maximum of 160 μs. When p is 3, the LBT period calculated from Table 1 is a minimum of 43 μs and a maximum of 9286 μs. When p is 4, the LBT period calculated from Table 1 is a minimum of 79 μs and a maximum of 9286 μs. Note that Table 1 is a table used for UL.

The LBT type and channel access priority class may be determined based on notifications from the base station 10, the channel type, etc. The 25 μs or 16 μs gap may be set by the base station 10 scheduling, taking into account the TA (Timing Advance) and CP extension.

The LBT applied to channel access is performed for each predetermined bandwidth (e.g., 20 MHz). This may be called an LBT channel, an RB set, or an LBT band, but is not limited to these. If no power is detected in the LBT channel that contains the respective transmission, the transmission can be performed. On the other hand, each CC in Uu may be defined with a bandwidth wider than the LBT channel. In other words, wideband operation is supported. Note that Uu is a radio interface between the UTRAN (Universal Terrestrial Radio Access Network) and the UE (User Equipment).

16 is a diagram for explaining an example (1) of channel transmission in an embodiment of the present invention. As shown in FIG. 16, for PSCCH/PSSCH transmission, two candidate starting symbols are supported in one slot. When a certain PSCCH/PSSCH transmission is performed in slot n, there is a possibility that the transmission cannot start at the first starting symbol (1st starting symbol, A) due to LBT failure. On the other hand, there is a possibility that the LBT will be successful at the second starting symbol (2nd starting symbol, B) in the middle of slot n. By enabling PSCCH/PSSCH transmission from the second starting symbol, it is possible to improve resource utilization efficiency. In addition, when starting transmission from the second starting symbol, a process may be performed in which a part of the PSSCH (e.g., the end) is not transmitted. Note that the description PSCCH/PSSCH may be replaced with PSCCH and/or PSSCH.

Here, it is necessary to determine the details of operation when two start symbol candidates are available. For example, it may be possible to specify the case when two start symbol candidates are available. For example, it may be possible to specify which position in the slot is to be the second start symbol. For example, it may be possible to specify the operation in the slot where the PSFCH opportunity is set. For example, it may be possible to specify the definition and indication of the length of the COT. For example, it may be possible to specify the operation of the receiving terminal 20.

For PSCCH/PSSCH transmission, a specific operation related to two starting symbol candidates in a slot may be applied. For example, the operations shown in operation 1) to operation 6) below may be applied.

Operation 1) The usage restrictions for the two starting symbol candidates may be specified as shown in a)-c) below.

a) If the configured or preconfigured parameters for the resource pool indicate that they are available, then it may be assumed that two starting symbol candidates are available. If the parameters do not indicate that they are available or are not configured, then it may be assumed that only the SL starting symbol for each slot is a starting symbol candidate.

b) In slots where no PSFCH opportunity is set, it may be assumed that two start symbol candidates are available. For example, in slots where a PSFCH opportunity is set, it may be assumed that only the SL start symbol of each slot is a start symbol candidate. For example, whether or not two start symbol candidates are available in a slot where a PSFCH opportunity is set may be determined by a set or pre-set parameter.

c) If the number of symbols available for SL in each slot (e.g., sl-LengthSymbols (see Non-Patent Document 5)) is a predetermined value, it may be assumed that two start symbol candidates are available. If the number of symbols available for SL in each slot is not the predetermined value, it may be assumed that only the SL start symbol of each slot is a start symbol candidate. For example, the predetermined value may be 14.

The above operation 1 allows two starting symbol candidates to be available only in limited cases. Therefore, the increase in UE complexity can be reduced.

Operation 2) In a resource pool that has two starting symbol candidates available, the usage restrictions for the second starting symbol may be specified as shown in a)-c) below.

a) When transmitting a certain PSCCH/PSSCH resource in slot n, if transmission from the first start symbol is attempted but cannot be transmitted due to an LBT failure, it may be permitted to attempt transmission from the second start symbol. In other words, if an LBT for transmission from the first start symbol is not performed, transmission from the second start symbol may not be permitted. As a result of the above, it is possible to operate in such a way that the resources of each slot are used as much as possible.

b) When transmitting a certain PSCCH/PSSCH in slot n, even if LBT for transmission from the first start symbol is not performed, transmission from the second start symbol may be attempted. This allows for improved flexibility in resource usage.

c) Whether a) or b) is used may be determined by a parameter that is set or preset.

d) If the transmission satisfies a predetermined condition, transmission from the second start symbol may be attempted, and if the predetermined condition is not met, only transmission from the first start symbol may be permitted. The predetermined condition may be any of the conditions shown in 1)-10) below.

1) The transmission is the first transmission of a TB (Transport block).
2) The transmission is a retransmission of a TB.
3) The transmission is a retransmission of a TB, and a transmission from the first start symbol has been previously performed in the same TB.
4) Information included in the transmitted PSSCH includes not only the second stage SCI but also the SL-SCH. Furthermore, the UE may be required to operate so as to satisfy this condition.
5) Regarding the information contained in the transmitted PSSCH, the SL-SCH is equal to or exceeds a predetermined amount. It may be further required that the UE operates to satisfy this condition.
6) For information contained in the transmitted PSSCH, a certain condition must be satisfied for each code block, e.g., the SL-SCH must be equal to or greater than a certain amount, and the UE may be required to operate in such a way that the condition is satisfied.
7) The transmission requires HARQ feedback.
8) Transmission in a slot where there is no PSFCH opportunity.
9) The transmission is of a predetermined cast type, which may be, for example, any one of unicast, groupcast option 1, groupcast option 2, and broadcast.
10) The transmission partner can receive transmissions from the second start symbol.

The above-mentioned operation 2) allows transmission from the second start symbol only in cases where it leads to improved resource utilization efficiency, and in cases where it is less or not effective, transmission can be made from the first start symbol.

Operation 3) The transmitted signal may be modified or altered as described below.

The mapping method for the code blocks included in the transmission TB may be notified via a specified signal (e.g., SCI).

FIG. 17 is a diagram for explaining an example (2) of channel transmission in an embodiment of the present invention. FIG. 18 is a diagram for explaining an example (3) of channel transmission in an embodiment of the present invention. FIG. 17 and FIG. 18 show an example of a code block mapping method when transmission starts from the second start symbol and the number of code blocks is 3 (CB#0, CB#1, CB#2).

As shown in FIG. 17, the fact that the code block numbers or code block indexes are mapped in ascending order may be notified via the specified signal. In the example of FIG. 17, in the PSSCH, the 2nd stage SCI, CB#0, and CB#1 are mapped in this order. Note that CB#2 is not transmitted because there is a shortage of PSSCH resources. As shown in FIG. 18, the fact that the code block numbers or code block indexes are mapped in descending order may be notified via the specified signal. In the example of FIG. 18, in the PSSCH, the 2nd stage SCI, CB#2, and CB#1 are mapped in this order. Note that CB#0 is not transmitted because there is a shortage of PSSCH resources. In other words, it becomes possible to transmit three code blocks (CB#0, CB#1, and CB#2) by two transmissions from the second start symbol.

Furthermore, the information mapping amount of each code block may be notified for multiple code blocks included in the transmission TB. For example, it may be notified whether a method in which the information mapping amount is greater for code blocks with larger code block numbers or code block indexes, or a conventional method in which the information mapping amount for each code block is approximately equal, is used. The determination of the information mapping amount in a method in which the information mapping amount is greater for code blocks with larger code block numbers or code block indexes may be defined in the specifications, may be set or preset, or may be provided by PC5-RRC signaling.

By using operation 3) above, when transmission starts from the second start symbol, it is possible to operate so as to send more of the information that could not be transmitted.

Action 4) The length of the COT may be defined, indicated or notified as described below.

If the transmission to acquire the COT begins with the second start symbol, the end of the COT may be determined as the timing when MCOT [ms] has elapsed from the second start symbol.

If the transmission to acquire the COT starts from the second start symbol, the end of the COT may be the end of the last slot that is MCOT [ms] after the second start symbol or before that time.

FIG. 19 is a diagram for explaining an example (4) of channel transmission in an embodiment of the present invention. As shown in FIG. 19, when a transmission for acquiring a COT starts from a second start symbol, the end of the COT may be the timing when MCOT [ms] has elapsed from the first start symbol immediately preceding the second start symbol.

Note that the timing when the MCOT has elapsed may be a timing determined based on an information notification for determining the end timing of the COT. The information for determining the end timing of the COT may be, for example, the start timing, end timing, COT length, etc.

By performing operation 4) above, the UEs can achieve a common understanding of MCOT.

Step 5) The position of the second starting symbol may be defined as a), b) or c) below.

a) The second start symbol may be X symbols after the first start symbol. X may be set by configuration or pre-setting. "Setting or pre-setting" may be replaced with "setting or pre-setting parameter". X may be determined regardless of the number of symbols C (e.g., sl-LengthSymbols (see non-patent document 5)) that can be used for SL in each slot, or may be defined or determined for each number of symbols C, or the value that can be set or pre-set as X may be different for each number of symbols C. Note that the number of symbols C may or may not include an AGC symbol and/or a gap symbol. Note that the timing of the end of the PSCCH/PSSCH may be after the AGC (Adaptive Gain Control) symbol or before the AGC symbol. Note that the AGC symbol may mean the first symbol of the SL transmission, and the gap symbol may be a symbol that is provided after the end of the SL transmission and is not transmitted/received, and CPE (Cyclic Prefix Extension) transmission may be performed.

b) The second start symbol may be Y symbols before the end of the PSCCH/PSSCH. Y may be determined regardless of the number of symbols C that can be used for SL in each slot (e.g., sl-LengthSymbols (see non-patent document 5)), or may be defined or determined for each number of symbols C, or the value that can be set or pre-set as Y may be different for each number of symbols C. Note that the number of symbols C may or may not include the AGC symbol and/or the gap symbol. Note that the end of the PSCCH/PSSCH may be after the gap symbol or before the gap symbol.

c) In each slot, the second start symbol may be half the number of symbols C that can be used for SL (e.g., sl-LengthSymbols (see non-patent document 5)). That is, the second start symbol may be C/2 symbols after the first start symbol, or the first start symbol may be C/2 symbols before the second start symbol. C/2 may be floor(C/2) or ceil(C/2).

Also, C may be replaced with C-Z, or Z may be 2. If C-2, symbols in each slot excluding the AGC symbol and gap symbol may be counted to determine the first start symbol and second start symbol.

By performing operation 5) above, it is possible to obtain a common understanding between the UEs regarding the position of the second start symbol. Also, it is possible to determine the start position so that the transmission from the second start symbol contains sufficient information.

Action 6) The receiving UE may act as follows: a), b) or c)

a) The UE may notify other UEs via PC5-RRC signaling whether reception from the second start symbol is possible.

b) If the UE is configured or pre-configured to perform transmission and reception from the second starting symbol, the UE may be required to perform reception from the second starting symbol.

c) If reception from the second starting symbol does not contain a sufficient amount of information to decode the TB, the receiving UE may operate as shown below in 1)-3).

1) A NACK may be sent without performing any decoding.
2) The transmitting UE may not transmit the PSFCH even if HARQ feedback is required.
3) The priority of the PSFCH to be transmitted may be reduced.

By performing operation 6) above, the transmitting UE can understand the operation of the receiving UE and perform transmission from the second start symbol.

In the above embodiment, a conventional SL channel and SL signal configuration is used, but this is not limiting. For example, this embodiment may also be applied when an interlaced channel is used as a configuration to satisfy the OCB requirements.

Note that the above-mentioned embodiment may be applied only when a certain condition is satisfied. For example, it may be applied in relation to a certain SL channel or SL signal. For example, this embodiment may be applied to any of PSCCH/PSSCH, PSFCH, S-SSB, and SL positioning RS. For example, it may be applied based on a certain setting or pre-setting. For example, this embodiment may be applied when "enabling" this embodiment is given by setting or pre-setting in the resource pool. For example, this embodiment may not be applied when the LBT method related to the second SL transmission is not or is no longer type 1.

In addition, to apply LBT type 2A, 2B or 2C, an additional transmission (additional TX), such as a CP extension, may be performed immediately before transmission P.

Note that the UE capabilities related to the applicability and operation of this embodiment may be defined, and may or may not be reported to the base station 10 and/or the terminal 20.

Note that the UE's SL transmission may be PSCCH, PSSCH, PSFCH, S-SSB, or SL-PRS, and different channels or signals may be applied to each operation in this embodiment.

In addition, at least one of the UE's SL transmissions may be UL transmission.

This embodiment may be applied to resource selection, resource reselection, reevaluation, and preemption checks.

The method in the embodiment of the present invention is not limited to the case of direct communication between terminals described above, but may be applied to other similar cases.

The above-described embodiment is not limited to V2X terminals, but may also be applied to terminals that perform D2D communication.

The above-described embodiment makes it possible to start channel transmission at multiple points within a unit time in direct communication between terminals in unlicensed bands.

In other words, it is possible to perform channel transmission for direct terminal-to-terminal communication that complies with regulations in unlicensed bands.

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

<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 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 20 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention.

The transmitting unit 110 has a function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiving unit 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signals. The transmitting unit 110 also 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 in a storage device the setting information that is set in advance and various setting information to be transmitted to the terminal 20, and reads it from the storage device as necessary. The content of the setting information is, for example, information related to the setting of D2D communication.

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

<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 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 21 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention.

The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiver 220 wirelessly receives various signals and acquires higher layer signals from the received physical layer signals. The receiver 220 also has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL/UL/SL control signals or reference signals, etc. transmitted from the base station 10. For example, the transmitter 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 receiver 220 receives PSCCH, PSSCH, PSDCH, PSBCH, etc. from the other terminal 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 a storage device, and reads it out from the storage device as necessary. The setting unit 230 also stores setting information that is set in advance. The content of the setting information is, for example, information related to the setting of D2D communication, etc.

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

(Hardware configuration)
The block diagrams (FIGS. 20 and 21) used in the description of the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. The method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or may be realized using two or more devices that are physically or logically separated and directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional blocks may be realized by combining the one device or the multiple devices with software.

Functions include, but are not limited to, judgement, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, regard, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs the transmission function is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on the method of realization for either of these.

For example, the base station 10, terminal 20, etc. in one 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 showing an example of the hardware configuration of the base station 10 and terminal 20 in one embodiment of the present disclosure. The above-mentioned base station 10 and terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

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

The functions of the base station 10 and the terminal 20 are realized by loading specific software (programs) onto hardware such as the processor 1001 and the storage device 1002, causing the processor 1001 to perform calculations, control communications by the communication device 1004, and control at least one of the reading and writing of data in the storage device 1002 and the auxiliary storage device 1003.

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

The processor 1001 reads out a program (program code), software module, 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 the program. The program is a program that causes a computer to execute at least a part of the operations described in the above-mentioned embodiment. 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 that runs on the processor 1001. 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 that runs on the processor 1001. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may be transmitted from a network via a telecommunication line.

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

The auxiliary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (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, etc. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium that includes at least one of the storage device 1002 and the auxiliary 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 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 a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., to realize at least one of, for example, Frequency Division Duplex (FDD) and Time Division Duplex (TDD). For example, the transmitting/receiving antenna, an amplifier unit, a transmitting/receiving unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmitting/receiving unit may be implemented as a transmitting unit or a receiving unit that is physically or logically separated.

The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that performs output to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one structure (e.g., a touch panel).

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

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

FIG. 23 shows an example configuration of a vehicle 2001. As shown in FIG. 23, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021-2029, an information service unit 2012, and a communication module 2013. Each aspect/embodiment described in this disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example.

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

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

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

The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information acquired from an external device via the communication module 2013 or the like to provide various multimedia information and multimedia services to the occupants of the vehicle 2001. The information service unit 2012 may include input devices (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, a touch panel, etc.) that accept input from the outside, and may also include output devices (e.g., a display, a speaker, an LED lamp, a touch panel, etc.) that perform output to the outside.

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

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

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

The communication module 2013 may transmit at least one of the signals from the various sensors 2021-2028 described above input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021-2028, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above input.

The communication module 2013 receives various information (traffic information, signal information, vehicle distance information, etc.) transmitted from an external device and displays it on the information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data/information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores various information received from an external device in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021 to 2029, etc. provided in the vehicle 2001.

(Summary of the embodiment)
As described above, according to an embodiment of the present invention, a terminal is provided that has a control unit that determines whether to start a transmission in an unlicensed band from the beginning of a section set for direct communication between terminals in a unit time or from the middle of the section, a receiving unit that performs a listen before talk (LBT) on an LBT channel for the transmission, and a transmitting unit that starts the transmission to other terminals from the determined point if the LBT is successful, and the control unit changes the signal of the transmission when the transmission is started from the middle of the section.

The above configuration makes it possible to start channel transmission at multiple points within a unit time in direct communication between terminals in unlicensed bands. In other words, it is possible to execute channel transmission for direct communication between terminals that complies with regulations in unlicensed bands.

The control unit may change the mapping method of the code block of the transmission when the transmission is started halfway through the section. With this configuration, efficient channel transmission can be started at multiple points within a unit time in direct communication between terminals in an unlicensed band.

When the control unit starts the transmission in the middle of the section, the control unit may map the multiple code blocks included in the transmission in ascending or descending order of index. This configuration makes it possible to start efficient channel transmission at multiple points within a unit time in direct communication between terminals in unlicensed bands.

When the control unit starts the transmission in the middle of the section, the control unit may consider the beginning of the section to be the starting point of MCOT (Maximum channel occupancy time). This configuration allows UEs to have a common understanding of MCOT in direct terminal-to-terminal communication in unlicensed bands.

The control unit may set the middle of the section to a position halfway through the section. This configuration makes it possible to start channel transmission at multiple points within a unit time in direct communication between terminals in unlicensed bands.

In addition, according to an embodiment of the present invention, a communication method is provided in which a terminal executes the following steps: determining whether a transmission in an unlicensed band should be started from the beginning of a section set for direct communication between terminals in a unit time or from within the section; executing a listen before talk (LBT) on an LBT channel for the transmission; starting the transmission to another terminal from the determined time if the LBT is successful; and changing the transmission signal if the transmission is to be started from within the section.

(Supplementary description of the embodiment)
Although the embodiment of the present invention has been described above, the disclosed invention is not limited to such an embodiment, and those skilled in the art will understand various modifications, modifications, alternatives, replacements, and the like. Although the description has been given using specific numerical examples to facilitate understanding of the invention, unless otherwise specified, those numerical values are merely examples and any appropriate value may be used. The division of items in the above description is not essential to the present invention, and items described in two or more items may be used in combination as necessary, and items described in one item may be applied to items described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operations of multiple functional units may be physically performed by one part, or the operations of one functional unit may be physically performed by multiple parts. The order of the processing procedures described in the embodiment may be changed as long as there is no contradiction. For convenience of the processing description, 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 operated by the processor possessed by the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor possessed by the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

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

Each aspect/embodiment described in this disclosure may be a mobile communication system (mobile communications system) for mobile communications over a wide range of networks, including LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal number)), FRA (Future Ra The present invention may be applied to at least one of systems using IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), and other appropriate systems, and next-generation systems that are expanded, modified, created, or defined based on these. It may also be applied to a combination of multiple systems (for example, a combination of at least one of LTE and LTE-A with 5G, etc.).

The processing steps, sequences, flow charts, etc. of each aspect/embodiment described herein may be reordered unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an exemplary order and are not limited to the particular order presented.

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

The information or signals described in this disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer). They may be input and output via multiple network nodes.

The input and output information may be stored in a specific location (e.g., memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be sent to another device.

The determination in this disclosure may be based on a value represented by one bit (0 or 1), a Boolean (true or false) value, or a comparison of numerical values (e.g., a comparison with a predetermined value).

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

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

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

Note that the terms explained in this disclosure and the terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and the symbol may be a signal (signaling). Also, the signal may be a message. Also, the component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

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

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

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

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

A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, and each smaller area 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 entire coverage area of at least one of the base station and base station subsystems that provide communication services in this coverage.

In this disclosure, a base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

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

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

At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a moving object, the moving object itself, etc. The moving object is a movable object, and the moving speed is arbitrary. It also includes the case where the moving object is stopped. The moving object includes, but is not limited to, for example, a vehicle, a transport vehicle, an automobile, a motorcycle, a bicycle, a connected car, an excavator, a bulldozer, a wheel loader, a dump truck, a forklift, a train, a bus, a handcar, a rickshaw, a ship and other watercraft, an airplane, a rocket, an artificial satellite, a drone (registered trademark), a multicopter, a quadcopter, a balloon, and objects mounted thereon. The moving object may also be a moving object that travels autonomously based on an operation command. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned moving object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). In addition, at least one of the base station and the mobile station may be 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.

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

Similarly, the user terminal in this disclosure may be interpreted as a base station. In this case, the base station may be configured to have the functions of the user terminal described above.

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

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

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

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

Any reference to an element using a designation such as "first," "second," etc., 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, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

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

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

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

Numerology may be a communication parameter that applies to at least one of the transmission and reception of a signal or channel. Numerology may indicate, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, a specific filtering process performed by the transceiver in the frequency domain, a specific windowing process performed by the transceiver in the time domain, etc.

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

A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

Radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals. Radio frame, subframe, slot, minislot, and symbol may each be referred to by a different name that corresponds to the radio frame, subframe, slot, minislot, and symbol.

For example, one subframe may be called a Transmission Time Interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. In other words, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

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

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

Note that when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit of scheduling. In addition, the number of slots (minislots) that constitute the minimum time unit of 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, etc. A TTI shorter than a normal TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

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

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

Furthermore, the time domain of an RB may include one or more symbols and may be one slot, one minislot, one subframe, or one TTI in length. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

In addition, one or more RBs may be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

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

A bandwidth part (BWP), which may also be referred to as a partial bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by an index of the RB relative to a common reference point of the carrier. PRBs may be defined in a BWP and numbered within the 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 within one carrier for the terminal 20.

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

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

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

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

Each aspect/embodiment described in this disclosure may be used alone, in combination, or switched between depending on the execution. In addition, notification of specific information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the specific information).

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

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 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Front wheel 2008 Rear wheel 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 Rotational speed sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system unit 2031 Microprocessor 2032 Memory (ROM, RAM)
2033 Communication port (IO port)

Claims

A control unit that determines whether a transmission is to be started from the beginning of a section set for terminal-to-terminal direct communication in a unit time or from the middle of the section in an unlicensed band;
A receiving unit that performs a listen before talk (LBT) on an LBT channel for the transmission;
A transmitting unit that starts the transmission to other terminals from the determined time point when the LBT is successful,
The control unit changes the transmission signal when the transmission is started midway through the section.
The terminal according to claim 1, wherein the control unit changes the mapping method of the code block of the transmission when the transmission is started in the middle of the section.
The terminal according to claim 1, wherein the control unit, when starting the transmission midway through the section, maps the multiple code blocks included in the transmission in ascending or descending order of indexes.
The terminal of claim 1, wherein the control unit assumes that the beginning of the section is the starting point of MCOT (Maximum channel occupancy time) when the transmission is started in the middle of the section.
The terminal according to claim 1, wherein the control unit sets the middle of the section as the halfway position of the section.
A step of determining whether a transmission should be started from the beginning of a section set for terminal-to-terminal direct communication in a unit time or from the middle of the section in an unlicensed band;
performing a listen before talk (LBT) on an LBT channel for the transmission;
If the LBT is successful, starting the transmission to other terminals from the determined time point;
and a procedure for changing the transmission signal when the transmission is started midway through the section, the terminal executing the communication method.