JP2024038533A - Terminal and communication method - Google Patents

Abstract

An object of the present invention is to improve the efficiency of resource selection operations through sensing during autonomous resource selection in direct communication between terminals. A terminal includes, in a resource pool, a receiving unit that performs sensing, a transmitting unit that selects a resource to be used for transmission based on the result of the sensing, and a control unit that determines whether the selected resource can be used. If the control unit determines that the selected resource cannot be used, the transmitting unit reselects the resource based on the already executed operation related to resource selection. [Selection diagram] Figure 19

Description

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

In LTE (Long Term Evolution) and LTE's successor systems (for example, LTE-A (LTE Advanced), NR (New Radio) (also referred to as 5G)), D2D is a system in which terminals communicate directly with each other without going through a base station. (Device to Device) technology is being considered (for example, 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 during a disaster or the like. Note that in 3GPP (3rd Generation Partnership Project), D2D is referred to as "sidelink," but in this specification, the more general term D2D is used. However, in the description of the embodiments to be described later, side links will also be used as necessary.

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

3GPP TS 38.211 V16.4.0 (2020-12) 3GPP TR 22.886 V15.1.0 (2017-03)

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

For example, after the terminal performs resource selection through sensing, if it is detected that the selected resource is unavailable, resource reselection may be performed. However, it is assumed that past slots corresponding to the timing of resource reselection are not monitored.

The present invention has been made in view of the above points, and an object of the present invention is to improve the efficiency of resource selection operation by sensing during autonomous resource selection in direct communication between terminals.

According to the disclosed technology, in a resource pool, a receiving unit that performs sensing, a transmitting unit that selects a resource to be used for transmission based on the result of the sensing, and a control that determines whether or not the selected resource can be used. If the control unit determines that the selected resource cannot be used, the transmitting unit reselects the resource based on an already executed operation related to resource selection.

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

It is a diagram for explaining V2X. FIG. 2 is a diagram for explaining an example (1) of a V2X transmission mode. FIG. 7 is a diagram for explaining an example (2) of V2X transmission mode. FIG. 7 is a diagram for explaining an example (3) of V2X transmission mode. FIG. 7 is a diagram for explaining an example (4) of V2X transmission mode. FIG. 7 is a diagram for explaining an example (5) of V2X transmission mode. FIG. 2 is a diagram for explaining an example (1) of V2X communication type. FIG. 6 is a diagram for explaining an example (2) of V2X communication type. FIG. 7 is a diagram for explaining an example (3) of V2X communication type. It is a sequence diagram which shows the example (1) of V2X operation. It is a sequence diagram which shows the example (2) of V2X operation. It is a sequence diagram which shows the example (3) of V2X operation. It is a sequence diagram which shows the example (4) of V2X operation. FIG. 3 is a diagram showing an example of sensing operation. 3 is a flowchart for explaining an example of preemption operation. FIG. 3 is a diagram illustrating an example of preemption operation. FIG. 6 is a diagram illustrating an example of partial sensing operation. FIG. 3 is a diagram for explaining an example of resource selection. It is a flowchart for explaining an example of communication in an embodiment of the present invention. 1 is a diagram showing an example of a functional configuration of a base station 10 in an embodiment of the present invention. It is a diagram showing an example of a functional configuration of a terminal 20 in an embodiment of the present invention. FIG. 2 is a diagram showing an example of the hardware configuration of a base station 10 or a terminal 20 in an embodiment of the present invention.

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

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

Further, in the 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 (for example, Flexible Duplex, etc.). This method may also be used.

Furthermore, in the embodiment of the present invention, "configure" the wireless parameters etc. may mean pre-configuring a predetermined value, or may mean that the base station 10 or Wireless parameters notified from the terminal 20 may also be set.

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

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

It is expected that studies on LTE or NR V2X that are not limited to 3GPP specifications will proceed in the future. For example, ensuring interoperability, reducing costs by implementing upper layers, how to use multiple RATs (Radio Access Technology) in combination or switching, compliance with regulations in each country, data acquisition and distribution of LTE or NR V2X platforms, database management, It is assumed that the usage method will be considered.

In the embodiments of the present invention, a mode in which the communication device is mounted on a vehicle is mainly assumed, but the embodiments of the present invention are not limited to this mode. 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, RSU, relay station (relay node), It may also be a terminal or the like that has scheduling capability.

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

Regarding OFDM (Orthogonal Frequency Division Multiplexing) of SL or UL, CP-OFDM (Cyclic-Prefix OFDM), DFT-S-OFDM (Discrete Fourier Transform - Spread - OFDM), OFDM without Transform precoding or Transform precoding Any of the following OFDM methods may be applied.

In LTE SL, Mode 3 and Mode 4 are defined regarding 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. Further, in Mode 3, SPS (Semi Persistent Scheduling) is also possible. In Mode 4, the terminal 20 autonomously selects transmission resources from the resource pool.

Note that the slot in the embodiment of the present invention may be read as a symbol, minislot, subframe, radio frame, or TTI (Transmission Time Interval). Further, the cell in the embodiment of the present invention may be read as a cell group, carrier component, BWP, resource pool, resource, RAT (Radio Access Technology), system (including wireless LAN), etc.

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

FIG. 2 is a diagram for explaining an example (1) of V2X transmission mode. In the sidelink communication transmission mode shown in FIG. 2, in step 1, the base station 10 transmits sidelink scheduling to the terminal 20A. Subsequently, the terminal 20A transmits a PSCCH (Physical Sidelink Control Channel) and a PSSCH (Physical Sidelink Shared Channel) to the terminal 20B based on the received scheduling (step 2). The transmission mode of sidelink communication shown in FIG. 2 may be referred to as sidelink transmission mode 3 in LTE. In sidelink transmission mode 3 in LTE, Uu-based sidelink scheduling is performed. Uu is a radio interface between UTRAN (Universal Terrestrial Radio Access Network) and UE (User Equipment). Note that the transmission mode of sidelink communication shown in FIG. 2 may be referred to as sidelink transmission mode 1 in NR.

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

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

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

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

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

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

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

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

Note that in the following description, PSFCH is used in transmitting HARQ-ACK on the side link, but this is just an example. For example, PSCCH may be used to transmit HARQ-ACK on the side link, PSSCH may be used to transmit HARQ-ACK on the side link, or other channels may be used to transmit HARQ-ACK on the side link. HARQ-ACK may be transmitted on the side link using the HARQ-ACK.

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

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

Hereinafter, unless the terminals 20A, 20B, etc. are particularly distinguished, they will be simply referred to as "terminal 20" or "user device." Although FIG. 10 shows, as an example, a case where both the terminal 20A and the terminal 20B are within the coverage of the cell, the operation in the embodiment of the present invention can also be applied when the terminal 20B is outside the coverage.

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

Note that the terminal 20 does not need to be a device in one housing; for example, even if various sensors are distributed and arranged in the vehicle, the terminal 20 may be a device including the various sensors.

Further, the processing content of the side link transmission data of the terminal 20 is basically the same as the processing content of UL transmission in LTE or NR. For example, the terminal 20 scrambles 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, the precoded complex-valued symbols are mapped to resource elements to generate a transmission signal (eg, a complex-valued time-domain SC-FDMA signal), and the signal is transmitted from each antenna port.

Note that the base station 10 has a cellular communication function as a base station in LTE or NR, and a function to enable communication of the terminal 20 in this embodiment (e.g., resource pool setting, resource allocation, etc.). have. Further, the base station 10 may be an RSU (gNB type RSU).

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

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. A resource selection window may be set from the base station 10 to the terminal 20. Here, regarding the predetermined period of the resource selection window, the period may be defined by terminal implementation conditions such as processing time or maximum allowable packet delay time, or the period may be defined in advance by specifications, The predetermined period may be called an interval in the time domain.

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

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

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

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

Note that if HARQ control with HARQ feedback is not performed, step S104 and step S105 may not be performed.

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

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

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

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

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

FIG. 12 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 side link resource used by the terminal 20 and transmit information indicating the resource to the terminal 20. Furthermore, when HARQ control with HARQ feedback is applied, the base station 10 may transmit information indicating 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 using the PDCCH. Hereinafter, for convenience, the DCI for SL scheduling will be referred to as SL scheduling DCI.

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

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

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

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

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

In step S305, the terminal 20A transmits, for example, the PUCCH ( The base station 10 receives the HARQ-ACK using the physical uplink control channel) resource. The HARQ-ACK codebook may include a HARQ-ACK generated based on the HARQ-ACK received from the terminal 20B or a PSFCH not received, and a HARQ-ACK for DL data. However, if DL data is not allocated, HARQ-ACK for DL data is not included. NR Rel. In No. 16, the HARQ-ACK codebook does not include HARQ-ACK for DL data.

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

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

In FIG. 13, the vertical axis corresponds to the frequency domain, and the horizontal axis corresponds to the time domain. The PSCCH may be placed in one symbol at the beginning of the slot, in multiple symbols from the beginning, or in multiple symbols starting from a symbol other than the beginning. The PSFCH may be placed in one symbol at the end of the slot, or may be placed in multiple symbols at the end of the slot. Note that the above-mentioned "head of slot" and "end of 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 "the end of the slot" mean the first and last symbols, respectively, among the 12 symbols excluding the first and last symbols. You can. In the example shown in FIG. 13, three subchannels are set in the resource pool, and two PSFCHs are arranged three slots after the slot in which the PSSCH is arranged. The arrow from PSSCH to PSFCH indicates an example of PSFCH associated with PSSCH.

If the HARQ response in the 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. 13, in step S401, the terminal 20A, which is the transmitting terminal 20, performs a group cast to the receiving terminals 20, which are the terminals 20B, 20C, and 20D, via the SL-SCH. In the following step S402, the terminal 20B uses PSFCH #B, the terminal 20C uses PSFCH #C, and the terminal 20D uses PSFCH #D to transmit the HARQ response to the terminal 20A. Here, as shown in the example of FIG. 13, if the number of available PSFCH resources is less than the number of receiving terminals 20 belonging to the group, it is necessary to decide how to allocate the PSFCH resources. . Note that the transmitting terminal 20 may know the number of receiving terminals 20 in the group cast. Note that in group cast option 1, only NACK is transmitted as the HARQ response, and ACK is not transmitted.

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

Furthermore, as shown in FIG. 14, the resource pool settings may have a periodicity. For example, the period may be a period of 10240 milliseconds. FIG. 14 is an example in which slot t ₀ ^SL to slot t _Tmax ^SL are set as a resource pool. Areas of the resource pool within each period may be set using, for example, a bitmap.

Further, as shown in FIG. 14, it is assumed that the 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 priority p _RX in the sensing window from slot nT ₀ to the slot immediately before slot nT _proc,0. . If an SCI is detected within the sensing window and RSRP (Reference Signal Received Power) exceeds a threshold, the resource within the resource selection window corresponding to the SCI is excluded. Further, if an SCI is detected within the sensing window and the RSRP is less than the threshold, the resource within the resource selection window corresponding to the SCI is not excluded. The thresholds may be, for example, thresholds Th _{pTX, pRX that} are set or defined for each resource within the sensing window based on the priority p _TX and the priority p RX.

Further, like slot t _m ^SL shown in FIG. 14, resources within the resource selection window that are candidates for resource reservation information corresponding to resources within the sensing window that are not monitored, for example, for transmission, are excluded.

As shown in FIG. 14, in the resource selection window from slot n+T ₁ to slot n+T ₂ , resources occupied by other UEs are identified, and resources from which these resources are excluded become usable resource candidates. Assuming that the set of usable resource candidates is S _A , if S _A is less than 20% of the resource selection window, the thresholds Th _{pTX and pRX} set for each resource in the sensing window are increased by 3 dB and the resource selection is performed again. Identification may be performed. That is, by increasing the thresholds Th _{pTX and pRX} and performing resource identification again, the number of resources that are not excluded because their RSRPs are less than the thresholds is increased, and the set of resource candidates S _A becomes 20% or more of the resource selection window. You may do so. If S _A is less than 20% of the resource selection window, the operation of increasing the thresholds Th _{pTX and pRX} set for each resource in the sensing window by 3 dB and performing resource identification again may be repeated.

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

In FIG. 14 described above, the operation of the transmitting terminal 20 has been explained, but the receiving terminal 20 detects data transmission from another terminal 20 based on the result of sensing or partial sensing, and transmits data to the other terminal 20. Data may be received from 20.

FIG. 15 is a flowchart illustrating an example of preemption in NR. FIG. 16 is a diagram showing an example of preemption in NR. In step S501, the terminal 20 performs sensing using the sensing window. When the terminal 20 performs power saving operation, sensing may be performed in a predefined limited period. Next, the terminal 20 identifies each resource within the resource selection window based on the sensing results, determines a resource candidate set _SA , and selects a resource to be used for transmission (S502). Subsequently, the terminal 20 selects a resource set (r_0, r_1, . . . ) for determining preemption from the resource candidate set _SA (S503). The resource set may be notified from the upper layer to the PHY layer as a resource for determining whether or not it has been preempted.

In step S504, the terminal 20 identifies each resource within the resource selection window again based on the sensing results and determines the resource candidate set S _A at timing T(r_0) _-T3 shown in FIG. , further determines whether to preempt the resource set (r_0, r_1, . . . ) based on the priority. For example, r_1 shown in FIG. 16 is not included in _SA because the SCI transmitted from another 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 own terminal, the terminal 20 uses the resource r_1. It is determined that it has been preempted. Note that the lower the value indicating the priority, the higher the priority. That is, if the value prio_RX indicating the priority of the SCI transmitted from the other terminal 20 is higher than the value prio_TX indicating the priority of the transport block transmitted from the own terminal, the terminal 20 does not exclude resource r_1 from _SA . . Alternatively, if preemption is valid only for a specific priority (for example, sl-PreemptionEnable is one of pl1, pl2, ..., pl8), this priority is set as prio_pre. At this time, if the value prio_RX indicating the priority of the SCI transmitted from the other terminal 20 is lower than prio_pre, and prio_RX is lower than the value prio_TX indicating the priority of the transport block transmitted from the own terminal, 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 the preemption, reselects resources in the upper layer, and ends the preemption check.

Note that when performing re-evaluation instead of checking preemption, in step S504 described above, after determining the set of resource candidates _SA , the resource set (r_0, r_1,...) is assigned to _SA . If the resource is not included, the resource is not used and the resource is reselected in the upper layer.

FIG. 17 is a diagram illustrating an example of partial sensing operation in NR. When partial sensing is configured from an upper layer on the NR sidelink, the terminal 20 selects a resource and performs transmission, as shown in FIG. 17. As shown in FIG. 17, the terminal 20 performs partial sensing for a portion of the sensing window in the resource pool, that is, the sensing target. Through partial sensing, the terminal 20 receives the resource reservation field included in the SCI transmitted from other terminals 20 and identifies available resource candidates within the resource selection window within the resource pool based on the field. . Subsequently, the terminal 20 randomly selects a resource from available resource candidates.

FIG. 17 is an example in which slot t ₀ ^SL to slot t _Tmax-1 ^SL are set as a resource pool. The target area of the resource pool may be set using, for example, a bitmap. As shown in FIG. 17, it is assumed that the transmission trigger in terminal 20 occurs in slot n. As shown in FIG. 17, Y slots from slot _ty1 ^SL to slot _tyY ^SL among slot n+T ₁ to slot n+T ₂ may be set as the resource selection window.

The terminal 20 detects, for example, that another terminal 20 is transmitting at one or more sensing targets from slot _ty1-k×Pstep ^SL to slot _tyY-k×Pstep ^SL , which has a length of Y slots. can do. k may be determined by a 10-bit bitmap, for example. FIG. 17 shows an example in which the third and sixth bits of the bitmap are set to "1" indicating that partial sensing is performed. That is, in FIG. 17, the sensing targets are set from slot _ty1-6×Pstep ^SL to slot _tyY-6×Pstep ^SL , and from slot _ty1-3×Pstep ^SL to slot _tyY-3×Pstep ^SL . be done. As mentioned above, the kth bit of the bitmap may correspond to the sensing window from slot t _y1-k×Pstep ^SL to slot t _yY-k×Pstep ^SL . Note that y _i corresponds to the index (1...Y) in the Y slot.

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

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

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

That is, by increasing the thresholds Th _{pTX and pRX} and performing resource identification again, the number of resources that are not excluded because the RSRP is less than the threshold may be increased. Furthermore, the RSSI of each resource in _SA may be measured, and the resource with the minimum RSSI may be added to the set _SB . The operation of adding the resource with the smallest RSSI included in _SA to _SB may be repeated until the resource candidate set _SB becomes 20% or more of the resource selection window.

The lower layer of the terminal 20 may report the _SB to the upper layer. The upper layer of the terminal 20 may perform random selection on the _SB to determine the resources to be used. The terminal 20 may perform sidelink transmission using the determined resources. Note that, once the terminal 20 secures the resource, it may periodically use the resource without performing sensing for a predetermined number of times (for example, _Cresel times).

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

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

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

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

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

The other one is Type D, and the Type D terminal 20 has the ability to receive all sidelink signals and channels defined in Release 16. However, this does not exclude receiving some sidelink signals and channels.

Note that UE types other than the above type A and type B may be assumed, and the UE type and the UE capability may or may not be associated with each other.

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

Here, it is assumed that after a resource is selected by partial sensing, re-evaluation or preemption check is performed. If the re-evaluation or preemption check detects or determines that the selected resource cannot be used, reselection of the resource may be performed.

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

Therefore, there is a need for a resource selection method that achieves low delay and low power consumption. Note that instead of re-evaluation or preemption check, it may be detected or determined that the selected resource cannot be used by congestion control.

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

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

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

Further, the operation related to predetermined resource selection in step S603 may be resource reselection performed based on information related to resource allocation at the time of resource selection. For example, the terminal 20 may perform resource reselection based on the resource set identified during resource selection. For example, the terminal 20 may reselect a resource from among the identified resource sets at the time of resource selection, from resources that are later than the resource reselection timing. For example, among the candidate resources when performing resource selection, the terminal 20 may target resources included in the interval [k+T ₁ , t_Y], where the last slot is t_Y and the resource reselection timing is k. . For example, the terminal 20 limits the resource candidates to be selected based on the sensing information used at the time of resource selection (for example, resources included in the interval [k+T ₁ , t_Y]), performs resource identification again, and identifies the identified resources. The resource may be reselected from the resource set. Note that _T1 may be _T1 , which is the time from slot n at which resource selection is executed to the start slot of the resource selection window.

Further, the operation related to predetermined resource selection in step S603 may be resource reselection performed based on information related to resource allocation at the time of re-evaluation or preemption check. For example, terminal 20 may perform resource reselection based on the resource set identified during the re-evaluation or preemption check. For example, the terminal 20 may reselect resources from among the identified resource sets at the time of re-evaluation or preemption check, from resources that are later than the resource reselection timing. For example, among the resources identified when performing a re-evaluation or preemption check, the terminal 20 selects the resources included in the interval [k+T ₁ , t_Y], where the last slot is t_Y and the resource reselection timing is k. It may also be a target. For example, the terminal 20 limits the resource candidates to be selected based on the sensing information used during the re-evaluation or preemption check (for example, resources included in the interval [k+T ₁ , t_Y]), and performs resource identification again. , resources may be reselected from the identified resource set. Note that _T1 may be _T1 , which is the processing time from slot n at which resource selection is executed to the start slot of the resource selection window.

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

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

Note that T _proc,0 may be the processing time from the last slot of the sensing window to resource selection. T _proc,1 may be the upper limit value of T ₁ above. _T3 may be the processing time from the beginning of the resource selection window at the time of re-evaluation or preemption check to the timing of re-evaluation or preemption check.

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

Further, the operation related to predetermined resource selection in step S603 may include performing additional sensing from the timing related to re-evaluation or preemption check to the timing of resource reselection, and reselecting the resource based on the sensing information. good. The timing related to resource selection may be any of 1) to 5) shown below.

1) the timing at which the re-evaluation or pre-emption check is triggered; 2) the timing of the re-evaluation or pre-emption check; 3) the slot for which resources are identified in the re-evaluation or pre-emption check; and 4) the processing time (e.g., T _proc,0 , T _proc,1 , _T3 , etc.)
5) Combination of 1)-4) above

In addition, the operation related to predetermined resource selection in step S603 is performed by performing resource identification again based on the above-mentioned additional sensing information in addition to the various parameters and sensing information used at the time of re-evaluation or preemption check. It may also be an operation of reselecting a resource from a resource set.

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

For example, the operation related to predetermined resource selection in step S603 may be resource reselection by random selection without using sensing information.

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

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

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

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

For example, when performing resource reselection by changing the resource allocation mechanism at the time of resource selection, the operation related to predetermined resource selection in step S603 may include subsequent resource selection, resource reselection, etc. related to the same transport block transmission. For operations related to re-evaluation and preemption, a modified resource allocation mechanism may be applied, a resource allocation mechanism before the change may be applied, or another resource allocation mechanism may be applied.

Note that the above-described embodiments may be applied to an operation in which a certain terminal 20 sets or allocates transmission resources for another terminal 20. That is, resource configuration or allocation may be performed such that the above-described embodiments are satisfied.

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

The operations according to the embodiments described above may be performed only in a specific resource pool. For example, it may be executed only in resource pools in which terminals 20 of release 17 or later can be used.

According to the above-described embodiment, when the terminal 20 detects that the selected resource cannot be used, the terminal 20 efficiently uses part of the information at the time of resource selection and the information at the time of re-evaluation or preemption check. Resources can be reselected.

That is, in direct communication between terminals, it is possible to improve the efficiency of resource selection operation by sensing during autonomous resource selection.

(Device configuration)
Next, an example of the functional configuration of the base station 10 and terminal 20 that execute the processes and operations described above will be described. Base station 10 and terminal 20 include functionality to implement the embodiments described above. However, the base station 10 and the terminal 20 may each have only some of the functions in the embodiment.

<Base station 10>
FIG. 20 is a diagram illustrating an example of the functional configuration of the base station 10. As shown in FIG. 20, base station 10 includes a transmitting section 110, a receiving section 120, a setting section 130, and a control section 140. The functional configuration shown in FIG. 20 is only an example. As long as the operations according to the embodiments of the present invention can be executed, the functional divisions and functional parts may have any names.

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

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

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

<Terminal 20>
FIG. 21 is a diagram illustrating an example of the functional configuration of the terminal 20. As shown in FIG. 21, the terminal 20 includes a transmitting section 210, a receiving section 220, a setting section 230, and a control section 240. The functional configuration shown in FIG. 21 is only an example. As long as the operations according to the embodiments of the present invention can be executed, the functional divisions and functional parts may have any names.

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

The setting unit 230 stores various setting information received from the base station 10 or the terminal 20 by the receiving unit 220 in a storage device, and reads it 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.

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

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

Functions include judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, These include, but are not limited to, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assigning. I can't do it. For example, a functional block (configuration unit) that performs transmission is called a transmitting unit or a transmitter. In either case, as described above, the implementation method is not particularly limited.

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

In addition, in the following description, the word "apparatus" can be read as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or more of each device shown in the figure, or may be configured not to include some of the devices.

Each function in the base station 10 and the terminal 20 is performed by loading predetermined software (programs) onto hardware such as the processor 1001 and the storage device 1002, so that the processor 1001 performs calculations and controls communication by the communication device 1004. This is realized by controlling at least one of reading and writing 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 with a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, registers, and the like. For example, the above-described control unit 140, control unit 240, etc. may be implemented by the processor 1001.

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

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

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

The communication device 1004 is hardware (transmission/reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, or the like. The communication device 1004 includes, for example, a high frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). It may be composed of. For example, a transmitting/receiving antenna, an amplifier section, a transmitting/receiving section, a transmission line interface, etc. may be realized by the communication device 1004. The transmitting and receiving unit may be physically or logically separated into a transmitting unit and a receiving unit.

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

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

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

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

With the above configuration, when the terminal 20 detects that the selected resource cannot be used, it can efficiently use the resource by using part of the information at the time of resource selection and the information at the time of re-evaluation or preemption check. can be reselected. That is, in direct communication between terminals, it is possible to improve the efficiency of resource selection operation by sensing during autonomous resource selection.

The receiving unit may perform partial sensing, and the transmitting unit may select resources to be used for transmission based on a result of the partial sensing. With this configuration, when the terminal 20 detects that the selected resource cannot be used through partial sensing, it can efficiently use the information at the time of resource selection and the information at the time of re-evaluation or preemption check. resources can be reselected.

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

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

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

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

With the above configuration, when the terminal 20 detects that the selected resource cannot be used, it can efficiently use the resource by using part of the information at the time of resource selection and the information at the time of re-evaluation or preemption check. can be reselected. That is, in direct communication between terminals, it is possible to improve the efficiency of resource selection operation by sensing during autonomous resource selection.

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

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

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

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

In this specification, specific operations performed by the base station 10 may be performed by its upper node in some cases. In a network consisting of one or more network nodes including a base station 10, various operations performed for communication with a terminal 20 are performed by the base station 10 and other network nodes other than the base station 10 ( It is clear that this can be done by at least one of the following: for example, MME or S-GW (possible, but not limited to). Although the case where there is one network node other than the base station 10 is illustrated above, the other network node may be a combination of multiple other network nodes (for example, MME and S-GW). .

The information, signals, etc. described in this disclosure may be output from an upper layer (or lower layer) to a lower layer (or upper layer). It may be input/output via multiple network nodes.

The input/output information may be stored in a specific location (eg, memory) or may be managed using a management table. Information etc. to be input/output may be overwritten, updated, or additionally written. The output information etc. may be deleted. The input information etc. may be transmitted to other devices.

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

Software includes instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, whether referred to as software, firmware, middleware, microcode, hardware description language, or by any other name. , should be broadly construed to mean an application, software application, software package, routine, subroutine, object, executable, thread of execution, procedure, function, etc.

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

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

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

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 expressed using absolute values, relative values from a predetermined value, or using other corresponding information. may be expressed. For example, radio resources may be indicated by an index.

The names used for the parameters described above are not restrictive in any respect. Furthermore, the mathematical formulas etc. using these parameters may differ from those explicitly disclosed in this disclosure. Since the various channels (e.g. PUCCH, PDCCH, etc.) and information elements may be identified by any suitable designation, the various names assigned to these various channels and information elements are in no way exclusive designations. isn't it.

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 (eg, three) cells. If a base station accommodates multiple cells, the overall coverage area of the base station can be partitioned into multiple smaller areas, and each smaller area is divided into multiple subsystems (e.g., small indoor base stations (RRHs)). The term "cell" or "sector" refers to a part or all of the coverage area of a base station and/or base station subsystem that provides communication services in this coverage. refers to

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

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

At least one of a base station and a mobile station may be called a transmitting device, a receiving device, a communication device, or the like. Note that at least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, or the like. The moving object may be a vehicle (for example, a car, an airplane, etc.), an unmanned moving object (for example, a drone, a self-driving car, etc.), or a robot (manned or unmanned). ). Note that at least one of the base station and the mobile station includes devices that do not necessarily move during communication operations. For example, at least one of the base station and 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 replaced by a user terminal. For example, communication between a base station and a user terminal is replaced with communication between a plurality of terminals 20 (for example, it may be called D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). Regarding the configuration, each aspect/embodiment of the present disclosure may be applied. In this case, the terminal 20 may have the functions that the base station 10 described above has. Further, words such as "up" and "down" may be replaced with words corresponding to inter-terminal communication (for example, "side"). For example, uplink channels, downlink channels, etc. may be replaced with side channels.

Similarly, the user terminal in the present disclosure may be replaced by a base station. In this case, the base station may have the functions that the user terminal described above has.

As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of operations. "Judgment" and "decision" include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, search, and inquiry. (e.g., searching in a table, database, or other data structure), and regarding an ascertaining as a "judgment" or "decision." In addition, "judgment" and "decision" refer to receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, and access. (accessing) (e.g., accessing data in memory) may include considering something as a "judgment" or "decision." In addition, "judgment" and "decision" refer to resolving, selecting, choosing, establishing, comparing, etc. as "judgment" and "decision". may be included. In other words, "judgment" and "decision" may include regarding some action as having been "judged" or "determined." Further, "judgment (decision)" may be read as "assuming", "expecting", "considering", etc.

The terms "connected", "coupled", or any variations thereof, refer to any connection or coupling, direct or indirect, between two or more elements and to each other. It may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled." The bonds or connections between elements may be physical, logical, or a combination thereof. For example, "connection" may be replaced with "access." As used in this disclosure, two elements may include one or more electrical wires, cables, and/or printed electrical connections, as well as in the radio frequency domain, as some non-limiting and non-inclusive examples. , electromagnetic energy having wavelengths in the microwave and optical (both visible and non-visible) ranges.

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 solely on" unless explicitly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

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

"Means" in the configurations of each of the above devices may be replaced with "unit", "circuit", "device", etc.

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

A radio frame may be composed of one or more frames in the time domain. Each frame or frames in the time domain may be called a subframe. A subframe may also be composed of one or more slots in the time domain. A subframe may have a fixed time length (eg, 1 ms) that does not depend on numerology.

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

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

A slot may include multiple minislots. Each minislot may be made up of one or more symbols in the time domain. Furthermore, a mini-slot may also be called a sub-slot. A minislot may be made up of fewer symbols than a slot. PDSCH (or PUSCH) transmitted in time units larger than minislots may be referred to as PDSCH (or PUSCH) mapping type A. PDSCH (or PUSCH) transmitted using minislots may be referred to as PDSCH (or PUSCH) mapping type B.

Radio frames, subframes, slots, minislots, and symbols all represent time units for transmitting signals. Other names may be used for 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, and one slot or minislot may be called a TTI. You can. In other words, at least one of the subframe and TTI may be a subframe (1ms) in existing LTE, a period shorter than 1ms (for example, 1-13 symbols), or a period longer than 1ms. It may be. 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 minimum time unit for scheduling in wireless communication. For example, in the LTE system, a base station performs scheduling to allocate radio resources (frequency bandwidth, transmission power, etc. that can be used by each terminal 20) to each terminal 20 on a TTI basis. Note that the definition of TTI is not limited to this.

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

Note that when one slot or one minislot is called a TTI, one or more TTIs (that is, one or more slots or one or more minislots) may be the minimum time unit for scheduling. Further, the number of slots (minislot number) that constitutes the minimum time unit of the scheduling may be controlled.

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

Note that long TTI (for example, normal TTI, subframe, etc.) may be read as TTI with a time length exceeding 1 ms, and short TTI (for example, short TTI, etc.) It may also be read as a TTI having the above TTI length.

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

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

Note that one or more RBs include physical resource blocks (PRBs), sub-carrier groups (SCGs), resource element groups (REGs), PRB pairs, RB pairs, etc. May be called.

Further, a resource block may be configured by one or more resource elements (REs). For example, 1 RE may be a radio resource region of 1 subcarrier and 1 symbol.

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

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

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

The structures of radio frames, subframes, slots, minislots, symbols, etc. described above 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 symbols included in an RB, Configurations such as the number of subcarriers, the number of symbols within a TTI, the symbol length, and the cyclic prefix (CP) length can be changed in various ways.

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

In this disclosure, the term "A and B are different" may mean "A and B are different from each other." Note that the term may also mean that "A and B are each different from C". Terms such as "separate" and "coupled" may also be interpreted similarly to "different."

Each aspect/embodiment described in this disclosure may be used alone, may be used in combination, or may be switched and used in accordance with execution. In addition, notification of prescribed information (for example, notification of "X") is not limited to being done explicitly, but may also be done implicitly (for example, not notifying the prescribed information). Good too.

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented as modifications and variations without departing from the spirit and scope of the present disclosure as determined by the claims. Therefore, the description of the present disclosure is for the purpose of illustrative explanation and is not intended to have any limiting meaning on the present disclosure.

10 Base station 110 Transmitting section 120 Receiving section 130 Setting section 140 Control section 20 Terminal 210 Transmitting section 220 Receiving section 230 Setting section 240 Control section 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims (6)

a receiving unit that performs sensing in the resource pool;
a transmitter that selects resources to be used for transmission based on the sensing results;
and a control unit that determines whether the selected resource can be used,
If the control unit determines that the selected resource cannot be used, the transmission unit reselects the resource based on an already executed operation related to resource selection. The terminal according to claim 1, wherein the receiving section executes partial sensing, and the transmitting section selects resources to be used for transmission based on a result of the partial sensing. 3. The terminal according to claim 2, wherein the already executed operation related to resource selection is a re-evaluation or a preemption check executed by the control unit on the selected resource. 4. The terminal according to claim 3, wherein the transmitter reselects the resource based on a resource set identified in a re-evaluation or preemption check performed by the controller on the selected resource. 5. The terminal according to claim 4, wherein the transmitting unit reselects a resource from a resource set identified in a re-evaluation or preemption check performed on the selected resource by the control unit. a receiving procedure for performing sensing in the resource pool;
a transmission procedure of selecting resources to be used for transmission based on the sensing results;
a control procedure for determining whether the selected resource can be used;
A communication method in which a terminal performs a procedure of reselecting a resource based on an operation related to resource selection that has already been performed when it is determined that the selected resource cannot be used.

Images