KR20220128232A - Method and apparatus for supporting sidelink discontinuous reception in wireless communication system - Google Patents

Abstract

The present disclosure relates to a method and apparatus for supporting sidelink discontinuous reception (DRX) in a wireless communication system. A communication method of a terminal in a wireless communication system supporting sidelink communication according to an embodiment of the present disclosure comprises the processes of: determining, when the terminal performs a DRX operation, a sensing section within a DRX active time; performing a sensing operation on a sidelink channel in the determined sensing section; and selecting or reselecting a sidelink resource based on the sensing operation.

Description

METHOD AND APPARATUS FOR SUPPORTING SIDELINK DISCONTINUOUS RECEPTION IN WIRELESS COMMUNICATION SYSTEM

The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for performing discontinuous reception (DRX) in a wireless communication system supporting side link communication.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a 4G network after (Beyond 4G Network) communication system or an LTE system after (Post LTE) system.

In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the very high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed.

In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway.

In addition, in the 5G system, the advanced coding modulation (ACM) methods FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), and advanced access technologies FBMC (Filter Bank Multi Carrier), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, in technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication), 5G communication technology is implemented by techniques such as beam forming, MIMO, and array antenna. there will be The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

The present disclosure provides a method and apparatus for efficiently supporting DRX in a wireless communication system supporting sidelink communication.

The present disclosure provides a method and apparatus for efficiently performing a sensing operation when a DRX operation is performed in a wireless communication system supporting sidelink communication.

The present disclosure provides a method and apparatus for resource selection when a DRX operation is performed in a wireless communication system supporting sidelink communication.

In addition, the present disclosure provides a method and apparatus for efficiently selecting a resource in a process in which a vehicle terminal exchanges information with another vehicle terminal and a portable pedestrian terminal using a sidelink in a wireless communication system supporting sidelink communication.

A communication method of a terminal in a wireless communication system supporting sidelink communication according to an embodiment of the present disclosure includes a process of determining a sensing period within a DRX active time when the terminal performs a DRX (Discontinuous Reception) operation; performing a sensing operation on a sidelink channel in the determined sensing period, and selecting or reselecting a sidelink resource based on the sensing operation.

In addition, in a wireless communication system supporting sidelink communication according to an embodiment of the present disclosure, a terminal, a transceiver, and when the terminal performs a DRX (Discontinuous Reception) operation, determines a sensing period within a DRX active time, and and a processor configured to perform a sensing operation on a sidelink channel in the determined sensing period, and to select or reselect a sidelink resource based on the sensing operation.

The present disclosure is intended to propose a procedure for sensing and selecting a resource when discontinuous reception (hereinafter referred to as DRX) is performed between terminals in sidelink communication. The proposed method can be applied and effectively used to minimize the power consumption of the terminal. In addition, through the proposed method, sensing and resource selection may be performed in a situation in which the terminal operates in DRX.

1 is a diagram illustrating a wireless communication system supporting sidelink communication according to an embodiment of the present disclosure;
2 is a diagram illustrating an example of a V2X communication method using sidelink communication according to an embodiment of the present disclosure;
3 is a diagram for explaining a resource pool defined as a set (set) of resources on time and frequency used for transmission and reception in sidelink communication according to an embodiment of the present disclosure;
4 is a flowchart illustrating a method for a base station to allocate transmission resources in sidelink communication according to an embodiment of the present disclosure;
5 is a flowchart illustrating a method in which a terminal directly allocates/selects a transmission resource of sidelink communication through sensing in sidelink communication according to an embodiment of the present disclosure;
6 is a diagram illustrating an example of a mapping structure of physical channels mapped to one slot in sidelink communication according to an embodiment of the present disclosure;
7 is a sensing window necessary for the terminal to perform resource (re)selection and re-evaluation for resource allocation/selection in sidelink communication when the terminal operates in full sensing according to an embodiment of the present disclosure; A drawing to explain the resource selection window (resource selection window),
8 and 9 are diagrams for explaining a method of performing partial sensing in sidelink communication according to an embodiment of the present disclosure;
10 is a diagram for explaining a method in which re-evaluation or pre-emption is additionally performed when partial sensing or random selection is performed in sidelink communication according to an embodiment of the present disclosure;
11A and 11B show inactive time (or off-duration) and active time (or on-duration) of DRX determined according to parameters configured for DRX when DRX operation is performed in sidelink communication according to an embodiment of the present disclosure; a drawing showing the duration),
12 to 14 are diagrams for explaining sensing methods of a terminal according to an embodiment of the present disclosure;
15 is a flowchart illustrating a terminal operation for sensing and resource selection when DRX is performed in sidelink communication according to an embodiment of the present disclosure;
16 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure;
17 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present disclosure;

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure without obscuring the gist of the present disclosure by omitting unnecessary description.

For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. In addition, the size of each component does not fully reflect the actual size. In each figure, the same or corresponding elements are assigned the same reference numerals.

Advantages and features of the present disclosure and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the present embodiments allow the present disclosure to be complete, and those of ordinary skill in the art to which the present disclosure pertains. It is provided to fully inform the person of the scope of the present disclosure, and the present disclosure is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

At this time, it will be understood that each block of the flowchart diagrams and combinations of the flowchart diagrams may be performed by computer program instructions. These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions performed by the processor of the computer or other programmable data processing equipment are not described in the flowchart block(s). It creates a means to perform functions. These computer program instructions may also be stored in a computer-usable or computer-readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, and thus the computer-usable or computer-readable memory. It is also possible for the instructions stored in the flowchart block(s) to produce an article of manufacture containing instruction means for performing the function described in the flowchart block(s). The computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to create a computer or other programmable data processing equipment. It is also possible that instructions for performing the processing equipment provide steps for performing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is also possible for the functions recited in the blocks to occur out of order. For example, it is possible that two blocks shown in succession are actually performed substantially simultaneously, or that the blocks are sometimes performed in the reverse order according to the corresponding function.

At this time, the term '~ unit' used in this embodiment means software or hardware components such as field programmable gate array (FPGA) or ASIC (application specific integrated circuit), and '~ unit' refers to what roles carry out However, '-part' is not limited to software or hardware. '~unit' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card. Also, in an embodiment, '~ unit' may include one or more processors.

In describing the embodiments of the present disclosure in detail, the wireless access network New RAN (NR) on the 5G mobile communication standard initiated by the 3rd generation partnership project long term evolution (3GPP), a mobile communication standard standardization organization, and the packet core as the core network ( 5G System, or 5G Core Network, or NG Core: next generation core), but the main gist of the present disclosure is other communication systems having a similar technical background in a range that does not significantly deviate from the scope of the present disclosure Applicable with slight modifications, which will be possible at the judgment of a person skilled in the art of the present disclosure.

In the 5G system, in order to support network automation, a network data collection and analysis function (NWDAF), which is a network function that provides a function to analyze and provide data collected from a 5G network, may be defined. NWDAF can collect/store/analyze information from the 5G network and provide the result to an unspecified network function (NF), and the analysis result can be used independently in each NF.

For convenience of description below, some terms and names defined in the 3GPP standard (standards of 5G, NR, LTE, or similar systems) may be used. However, the present disclosure is not limited by terms and names, and may be equally applied to systems conforming to other standards.

In addition, a term for identifying an access node used in the following description, a term referring to a network entity, a term referring to messages, a term referring to an interface between network entities, and various identification information Terms and the like referring to them are exemplified for convenience of description. Therefore, it is not limited to the terms used in the present disclosure, and other terms referring to objects having equivalent technical meanings may be used.

In a 5G communication system, a plurality of services may be provided to a user, and in order to provide such a plurality of services to a user, a method and an apparatus using the same are required to provide each service within the same time period according to characteristics. Various services provided in the 5G communication system are being studied, and one of them is a service that satisfies the requirements of low latency and high reliability. In particular, in the case of vehicle communication, in the NR V2X system, unicast communication, groupcast (or multicast) communication, and broadcast communication between the terminal and the terminal are supported. In addition, NR V2X is different from LTE V2X, which aims to transmit and receive basic safety information necessary for vehicle road driving. We aim to provide more advanced services together. An example of sidelink communication supported by the 5G communication system is vehicle-to-everything (V2X) communication. Hereinafter, a V2X terminal is exemplified as an example of a terminal performing sidelink communication for convenience of description in the embodiments of the present disclosure, but embodiments of the present disclosure are applied to various sidelink communication to which the present disclosure can be applied as well as V2X communication. can

In the sidelink communication, the terminal may select a transmission resource for sidelink transmission through direct sensing. Here, sensing is an operation in which the UE monitors a sidelink channel, and may include monitoring/decoding of a physical sidelink control channel (PSCCH) and measurement of a sidelink reference signal received power (SL-RSRP). In this case, various sensing and resource selection methods may be considered according to the state of the terminal and the transmission environment. Specifically, the following resource selection mode/method may be used.

- full sensing

- partial sensing

- random selection

In the above methods, the full sensing is a method of performing sensing in a section defined as a sensing window except for a slot in which the terminal performs sidelink transmission. In the case of full sensing, since continuous monitoring has to be performed in the section defined as the sensing window, there is a disadvantage in that the power consumption of the terminal increases. For a detailed description thereof, refer to FIG. 7 and related detailed description to be described later. Therefore, the partial sensing and random selection can be considered in consideration of the low power consumption of the terminal. In the present disclosure, for convenience of description, the partial sensing and random selection are named power saving mode. In the case of partial sensing, the slot for sensing is limited compared to full sensing. As a more detailed method, methods such as periodic-based partial sensing and contiguous partial sensing can be considered. For a detailed description thereof, refer to FIGS. 8 and 9 and related detailed descriptions to be described later. In addition, the random selection is a method in which the UE randomly performs resource selection. Therefore, in the case of random selection, a sensing operation may not be required. Even when random selection is performed, there may be a terminal that cannot perform sensing due to power consumption and a terminal that can sense. Note that, in the case of a terminal performing random selection but capable of performing sensing, sensing may be performed. The sensing at this time may be for performing re-evaluation or pre-emption. Compared to full sensing, when partial sensing or random selection is performed, the sensing window for re-evaluation and pre-emption needs to be set differently. For a detailed description thereof, refer to FIG. 10 and related detailed description to be described later.

In particular, DRX may be considered between terminals in sidelink communication. When DRX is applied in sidelink communication, it is possible to increase battery efficiency by minimizing power consumption of the terminal. Specifically, the power consumed by the terminal may be generated in the following process.

- Decoding of ^1st SCI of control information transmitted through ^PSCCH : 1st SCI includes scheduling information of the UE, so that information can be used to perform sensing by performing ^1st SCI decoding

- Decoding of control information ^2nd SCI transmitted through PSSCH: ^2nd SCI includes other control information not included in ^1st SCI

- Decoding of data transmitted through PSSCH

In the sidelink communication, the transmitting terminal transmits sidelink control information (SCI) for scheduling sidelink data to the receiving terminal through a physical sidelink control channel (PSCCH), and the physical sidelink The sidelink data is transmitted through a physical sidelink shared channel (PSSCH). Also, the SCI may be transmitted through the PSSCH. The SCI includes resource allocation information used for transmission of the sidelink data, modulation and coding scheme (MCS) information applied to sidelink data, group destination ID information, source ID information, and uni Cast destination ID (unicast destination ID) information, power control information for controlling sidelink power, timing advance (TA) information, DMRS configuration information for sidelink transmission, packet repetition transmission related information, and sidelink data It may include at least one of feedback information (A/N information) for

In sidelink communication, DRX is applied and in a time interval set as an inactive time, the UE may not perform decoding on the control information and data information. On the contrary, in a time period set as an active time by applying DRX, the terminal may perform decoding on the control information and data information. Therefore, in the DRX inactive time interval in sidelink communication, a case may occur where the UE cannot perform channel sensing for resource selection. In the present disclosure, when DRX is performed in sidelink communication, a case in which restrictions may occur in the operation of sensing and resource selection of the terminal is described, and solutions for such a case and the operation of the terminal are proposed.

1 is a diagram illustrating a wireless communication system supporting sidelink communication according to an embodiment of the present disclosure.

Referring to FIG. 1, (a) of FIG. 1 shows an example of a case (In-Coverage, IC) in which all V2X terminals (UE-1 and UE-2) are located within the coverage of the base station. All V2X terminals may receive data and control information from the base station through downlink (DL) or transmit data and control information through uplink (UL) to the base station. In this case, the data and control information may include data and control information for V2X communication. Also, the data and control information may be data and control information for general cellular communication. In addition, V2X terminals may transmit/receive data and control information for V2X communication through a sidelink (SL).

Referring to FIG. 1, (b) of FIG. 1 shows an example of a case in which UE-1 is located within the coverage of the base station and UE-2 is located outside the coverage of the base station among V2X terminals. That is, Figure 1 (b) shows an example of partial coverage (partial coverage, PC) in which some V2X terminals (UE-2) are located outside the coverage of the base station. A V2X terminal (UE-1) located within the coverage of the base station may receive data and control information from the base station through downlink or transmit data and control information through uplink to the base station. A V2X terminal (UE-2) located outside the coverage of the base station cannot receive data and control information from the base station through downlink, and cannot transmit data and control information through uplink to the base station. The V2X terminal UE-2 may transmit/receive data and control information for V2X communication through a sidelink with the V2X terminal UE-1.

Referring to FIG. 1, (c) of FIG. 1 shows an example of a case in which all V2X terminals are located outside the coverage of the base station (out-of coverage, OOC). Therefore, the V2X terminals (UE-1, UE-2) cannot receive data and control information from the base station through the downlink, and cannot transmit data and control information through the uplink to the base station. V2X terminals (UE-1, UE-2) may transmit/receive data and control information for V2X communication through a sidelink.

Referring to FIG. 1, (d) of FIG. 1 shows an example of a scenario in which V2X communication is performed between V2X terminals (UE-1, UE-2) located in different cells. Specifically, (d) of FIG. 1 shows that V2X terminals (UE-1, UE-2) are connected to different base stations (RRC (Radio Resource Control) connection state) or camping (RRC connection release state, That is, RRC idle state) is shown. At this time, the V2X terminal (UE-1) may be a V2X transmitting terminal and the V2X terminal (UE-2) may be a V2X receiving terminal. Alternatively, the V2X terminal (UE-1) may be a V2X receiving terminal, and the V2X terminal (UE-2) may be a V2X transmitting terminal. The V2X terminal (UE-1) may receive a system information block (SIB) from the base station to which it is connected (or to which it is camping), and the V2X terminal (UE-2) is connected to (or by itself). It can receive SIB from another base station (which is camping). At this time, as the SIB, an existing SIB or a SIB defined separately for V2X may be used. In addition, information on the SIB received by the V2X terminal UE-1 and information on the SIB received by the V2X terminal UE-2 may be different from each other. Therefore, in order to perform V2X communication between terminals (UE-1, UE-2) located in different cells, information is unified or information about this is signaled, and a method of interpreting SIB information transmitted from different cells is additionally required. may be

1 illustrates a V2X system composed of V2X terminals (UE-1, UE-2) for convenience of description, but communication may be performed between two or more V2X terminals without being limited thereto. In addition, the interface (uplink and downlink) between the base station and the V2X terminals may be named a Uu interface, and the sidelink between the V2X terminals may be named a PC5 interface. Therefore, in the present disclosure, these may be used interchangeably. On the other hand, in the present disclosure, the terminal supports vehicle-to-vehicle communication (vehicular-to-vehicular, V2V), vehicle-to-pedestrian communication (vehicular-to-pedestrian, V2P) supporting vehicle or pedestrian handset (for example, , smartphones), vehicles supporting vehicle-to-network communication (vehicular-to-network, V2N), or vehicles supporting vehicle-to-infrastructure communication (vehicular-to-infrastructure, V2I). have. In addition, in the present disclosure, the terminal may include a roadside unit (RSU) equipped with a terminal function, an RSU equipped with a base station function, or an RSU equipped with a part of the base station function and a part of the terminal function. The RSU may be installed in various facility(s) around the road, such as traffic lights, tunnels, intersections, and the like.

In addition, according to an embodiment of the present disclosure, the base station may be a base station supporting both V2X communication and general cellular communication, or a base station supporting only V2X communication. In this case, the base station may be a 5G base station (gNB), a 4G base station (eNB), or an RSU. Accordingly, in this disclosure, the base station may be referred to as an RSU.

2 is a diagram illustrating an example of a V2X communication method using sidelink communication according to an embodiment of the present disclosure.

Referring to (a) of Figure 2, UE-1 (201, for example, TX terminal) and UE-2 (202, for example, RX terminal) may perform one-to-one communication, and this It can be called cast (unicast) communication.

Referring to (b) of FIG. 2 , the TX terminal and the RX terminal may perform one-to-many communication, which may be referred to as a groupcast or multicast. In (b) of FIG. 2 , UE-1 211 , UE-2 212 , and UE-3 213 form one group (Group A) to perform groupcast communication. and UE-4 214 , UE-5 215 , UE-6 216 , and UE-7 217 form another group (Group B) to communicate with groupcast (groupcast) can be performed. Each terminal performs groupcast communication only within a group to which it belongs, and communication between different groups may be performed through unicast, groupcast, or broadcast communication. Although it is shown that two groups (Group A, Group B) are formed in (b) of FIG. 2 , the present invention is not limited thereto.

On the other hand, although not shown in Figure 2, V2X terminals can perform broadcast (broadcast) communication. Broadcast communication means a case in which all V2X terminals receive data and control information transmitted by a V2X transmitting terminal through a sidelink. As an example, when it is assumed that UE-1 211 in FIG. 2B is a transmitting terminal for broadcast, all terminals (UE-2 212 , UE-3 213 , UE -4 214 , UE-5 215 , UE-6 216 , and UE-7 217 ) may receive data and control information transmitted by UE-1 211 .

In NR V2X, support of a form in which a vehicle terminal transmits data to only one specific node through unicast and a form in which data is transmitted to a number of specific nodes through a groupcast can be considered, unlike in LTE V2X. For example, these unicast and group cast technologies can be usefully used in service scenarios such as platooning, which is a technology for moving two or more vehicles in a group by connecting them to one network. Specifically, unicast communication may be required for the purpose of controlling one specific node by the leader node of a group connected by group driving, and group cast communication may be required for the purpose of simultaneously controlling a group consisting of a number of specific nodes. can

3 is a diagram for explaining a resource pool defined as a set (set) of resources on time and frequency used for transmission and reception in sidelink communication according to an embodiment of the present disclosure.

A resource granularity of a time axis/domain in the resource pool may be a slot. Also, a resource allocation unit of a frequency axis/domain may be a sub-channel composed of one or more physical resource blocks (PRBs). In the present disclosure, an example of a case in which the resource pool is non-contiguously allocated in time is described, but the resource pool may be continuously allocated in the time domain. In addition, in the present disclosure, an example of a case in which the resource pool is continuously allocated in the frequency domain is described, but a method in which the resource pool is non-contiguously allocated in the frequency domain is not excluded.

,

,

,...)로 도시 되었다. 301에서 음영으로 도시된 부분은 자원 풀에 속한 사이드링크 슬롯들을 나타낸다. 자원 풀에 속한 사이드링크 슬롯들은 비트맵을 통해 자원 풀 정보로 (pre-)configuration될 수 있다. 302를 참조하면, 시간 영역에서 자원 풀에 속한 사이드링크 슬롯의 셋(집합)이 (

,

,

,...)로 도시 되어 있다. 본 개시에서 (pre-)configuration의 의미는 단말에 pre-configuration되어 미리 저장되어 있는 설정 정보를 의미할 수도 있고, 단말이 기지국으로부터 cell-common한 방법으로 configuration되는 경우를 의미할 수 도 있다. 여기서 cell-common은 셀안의 단말들이 기지국으로부터 동일한 정보의 설정 정보를 수신함을 의미할 수 있다. 이때, 단말은 기지국으로부터 사이드링크 SL-SIB (sidelink system information block)을 수신하여 cell-common한 정보를 획득하는 방법이 고려될 수 있다. 또한 단말이 기지국과 RRC 연결이 수립된 이후 UE-specific한 방법으로 configuration되는 경우를 의미할 수 도 있다. 여기서 UE-specific은 UE-dedicated라는 용어로 대체될 수도 있으며 단말마다 특정한 값으로 설정 정보를 수신함을 의미할 수 있다. 이때, 단말은 기지국으로부터 RRC 메시지를 수신하여 UE-specific한 정보를 획득하는 방법이 고려될 수 있다. 또한 (pre-)configuration은 자원 풀 정보로 설정되는 방법과 자원 풀 정보에 설정되지 않는 방법이 고려될 수 있다. 자원 풀 정보로 (pre-)configuration되는 경우는 단말이 기지국과 RRC 연결이 수립된 이후 UE-specific한 방법으로 configuration되는 경우를 제외하고는 해당 자원 풀에서 동작하는 단말들은 모두 공통된 설정 정보로 동작될 수 있다. 하지만 (pre-)configuration이 자원 풀 정보에 설정되지 않는 방법은 기본적으로 자원 풀 설정 정보와 독립적으로 설정되는 방법이다. 예를 들어, 자원 풀에 하나 이상의 모드가 (pre-)configuration 되고 (예를 들어, A, B, 그리고 C) 자원 풀 설정 정보와 독립적으로 (pre-)configuration된 정보가 자원 풀에 (pre-)configuration된 모드 중 어떤 모드를 사용할지 (예를 들어, A 또는 B 또는 C)를 지시해 줄 수 있다. Referring to FIG. 3, a case 301 in which the resource pool is non-contiguously allocated in the time domain is illustrated. A case in which (granularity) consists of slots is shown. First, the sidelink slot may be defined within a slot used for uplink. Specifically, the length (eg, number of symbols) of symbol(s) used as a sidelink in one slot may be set as sidelink BWP (Bandwidth Part) information. Therefore, among the slots used for the uplink, the slots in which the length (number of symbols) of the symbol(s) configured as the sidelink are not guaranteed cannot be the sidelink slots. In addition, slots belonging to the resource pool are excluded from slots in which S-SSB (Sidelink Synchronization Signal Block) is transmitted. Referring to 301, except for such slots, a set (set) of slots that can be used as a sidelink in the time domain is (

,

,

,...) was shown. The shaded portions at 301 indicate sidelink slots belonging to the resource pool. Sidelink slots belonging to the resource pool may be (pre-)configured with resource pool information through a bitmap. Referring to 302, the set (set) of sidelink slots belonging to the resource pool in the time domain is (

,

,

,...) are shown. In the present disclosure, the meaning of (pre-)configuration may mean configuration information pre-configured in the terminal and stored in advance, or may mean a case in which the terminal is configured in a cell-common manner from the base station. Here, cell-common may mean that terminals in a cell receive configuration information of the same information from the base station. In this case, a method of obtaining cell-common information by receiving a sidelink SL-SIB (sidelink system information block) from the base station may be considered. It may also mean a case in which the terminal is configured in a UE-specific manner after the RRC connection with the base station is established. Here, UE-specific may be replaced with the term UE-dedicated, and may mean that configuration information is received with a specific value for each UE. In this case, a method of obtaining UE-specific information by receiving an RRC message from a base station may be considered. In addition, (pre-)configuration may consider a method set by the resource pool information and a method not set in the resource pool information. In the case of (pre-)configuration with resource pool information, all terminals operating in the resource pool are operated with common configuration information, except when the terminal is configured in a UE-specific manner after RRC connection with the base station is established. can However, the method in which (pre-)configuration is not set in the resource pool information is basically a method that is set independently of the resource pool configuration information. For example, one or more modes are (pre-)configured in the resource pool (eg, A, B, and C), and information that is (pre-)configured independently of the resource pool configuration information is (pre-)configured in the resource pool. ) can indicate which of the configured modes to use (eg, A or B or C).

Referring to 303 in FIG. 3, a case in which the resource pool is continuously allocated on a frequency is illustrated. In the frequency axis, resource allocation may be set with sidelink BWP (Bandwidth Part) information and may be performed in units of sub-channels. The subchannel may be defined as a resource allocation unit on a frequency composed of one or more physical resource blocks (PRBs). For example, a subchannel may be defined as an integer multiple of PRB. Referring to 303, the subchannel may be composed of, for example, five consecutive PRBs, and the size of the subchannel (sizeSubchannel) may be the size of five consecutive PRBs. However, the content shown in the drawings is only an example of the present disclosure, and the size of the subchannel may be set differently, and although it is common that one subchannel is configured as a continuous PRB, it is not necessarily configured as a continuous PRB. A subchannel may be a basic unit of resource allocation for the PSSCH. In 303, startRB-Subchannel may indicate the start position of a subchannel on a frequency in the resource pool. When resource allocation is performed in units of subchannels on the frequency axis, the RB (Resource Block) index (startRB-Subchannel) at which the subchannel starts, information on how many PRBs the subchannel consists of (sizeSubchannel), and the total number of subchannels A resource on a frequency may be allocated through configuration information on (numSubchannel) and the like. In this case, information on startRB-Subchannel, sizeSubchannel, and numSubchannel may be (pre-)configured as resource pool information on frequency.

4 is a flowchart illustrating a method for a base station to allocate transmission resources in sidelink communication according to an embodiment of the present disclosure.

A method for the base station to allocate transmission resources in sidelink communication will be referred to as Mode 1 hereinafter. Mode 1 may be a scheduled resource allocation (scheduled resource allocation). Mode 1 may indicate a method in which the base station allocates resources used for sidelink transmission to RRC-connected terminals in a dedicated scheduling method. The method of Mode 1 can be effective for interference management and resource pool management because the base station can manage sidelink communication resources.

Referring to FIG. 4 , a transmitting terminal 401 may camp on a base station (cell) 403 ( 405 ). The camp on is, for example, a state in which a terminal in a standby state (RRC_IDLE) can select (or reselect) a base station (cell) as needed and receive system information or paging information. have.

Meanwhile, when the receiving terminal 402 is located within the coverage of the base station (cell) 403 , the receiving terminal 402 may camp on the base station (cell) 403 ( 407 ). On the other hand, when the receiving terminal 402 is located outside the coverage of the base station (cell) 403 , the receiving terminal 402 may not camp on the base station (cell) 403 .

In the present disclosure, the receiving terminal 402 represents a terminal receiving data transmitted by the transmitting terminal 401 .

The transmitting terminal 401 and the receiving terminal 402 may each receive a sidelink system information block (SL-SIB) from the base station 403 ( 410 ). The SL-SIB information includes sidelink resource pool information for transmission and reception in sidelink communication, parameter setting information for a sensing operation for resource selection, information for setting sidelink synchronization, or operating at different frequencies. Carrier information for sidelink transmission and reception may be included. The transmitting terminal 401 and the receiving terminal 402 may perform RRC setup for sidelink communication through the PC5 interface ( 415 ).

When data traffic for V2X communication is generated in the transmitting terminal 401, the transmitting terminal 401 may be RRC-connected to the base station 403 (420). Here, the RRC connection between the terminal and the base station may be referred to as Uu-RRC. The Uu-RRC connection process 420 may be performed before data traffic generation of the transmitting terminal 401 . Also, in the Mode 1, the transmitting terminal 401 can transmit to the receiving terminal 402 through the sidelink in a state in which the Uu-RRC connection process 420 between the base station 403 and the receiving terminal 402 is performed. have. Contrary to this, in Mode 1, the transmitting terminal 401 transmits to the receiving terminal 402 through the sidelink even when the Uu-RRC connection process 420 between the base station 403 and the receiving terminal 402 is not performed. can be performed.

The transmitting terminal 401 may request a transmission resource capable of performing V2X communication with the receiving terminal 402 from the base station (430). At this time, the transmitting terminal 401 requests the base station 403 for a sidelink transmission resource using an uplink physical uplink control channel (PUCCH), an RRC message, or a medium access control (MAC) control element (CE). can On the other hand, the MAC CE is a buffer status report of a new format (including information on the size of data buffered for at least an indicator indicating that it is a buffer status report for V2X communication and D2D (device to device) communication), BSR) MAC CE or the like. Also, the transmitting terminal 401 may request a sidelink resource through a scheduling request (SR) bit transmitted through an uplink physical control channel (PUCCH). In addition, in the case of Mode 1, the terminal may additionally signal information that can help the base station to schedule the base station. This can be done using RRC messages or MAC CEs. In the present disclosure, the method of indicating the corresponding information is not limited thereto. Also, the corresponding information may be named UEAssistanceInformation.

Next, the base station 403 may allocate a V2X transmission resource to the transmission terminal 401 . In this case, the base station may allocate transmission resources in a dynamic grant or configured grant method.

First, in the case of the dynamic grant method, the base station may allocate resources for TB transmission through downlink control information (DCI). The sidelink scheduling information included in DCI may include parameters related to transmission time and frequency allocation location information fields of initial transmission and retransmission. DCI for the dynamic grant scheme may be CRC scrambled with SL-V-RNTI to indicate that it is a dynamic grant scheme.

Next, in the case of the configured grant method, the base station may periodically allocate resources for TB transmission by setting a semi-persistent scheduling (SPS) interval through Uu-RRC. In this case, the base station may allocate resources for one TB through DCI. The sidelink scheduling information for one transport block (TB) included in DCI may include parameters related to transmission time and frequency allocation location information of initial transmission and retransmission resources. When the resource is allocated in the configured grant method, the transmission time / opportunity and frequency allocation position of the initial transmission and retransmission for one TB may be determined by the DCI, and the resource for the next TB is repeated at SPS interval intervals can be DCI for the configured grant method may be CRC scrambled with SL-SPS-V-RNTI to indicate that it is a configured grant method. Activation/retransmission/reactivation/release of SPS transmission in sidelink communication may be indicated to the UE through the PDCCH, and the SL-SPS-V-RNTI is an identifier for identifying the UE at this time. In addition, the configured grant (CG) method can be divided into Type1 CG and Type2 CG. In the case of Type2 CG, it is possible to activate / deactivation a resource set as a grant configured through DCI.

Accordingly, in the case of Mode 1, the base station 403 may instruct the transmitting terminal 401 to schedule for sidelink communication with the receiving terminal 402 through DCI transmission through the PDCCH (440).

Specifically, DCI format 3_0 or DCI format 3_1 used by the base station 403 for sidelink communication to the transmitting terminal 401 may be included. The DCI format 3_0 may be DCI for scheduling an NR sidelink in one cell, and DCI format 3_1 may be a DCI for scheduling an LTE sidelink in one cell.

In the case of broadcast transmission, the transmitting terminal 401 may perform transmission without the RRC setting 415 for the sidelink. Contrary to this, in the case of unicast or groupcast transmission, the transmitting terminal 401 may perform RRC connection with another terminal on a one-to-one basis. Here, the RRC connection between terminals may be referred to as a PC5-RRC 415 to be distinguished from the Uu-RRC. In the case of groupcast, the PC5-RRC 415 may be individually connected between the terminals in the group and the terminals. Referring to FIG. 4 , although the connection of the PC5-RRC 415 is shown as an operation after the transmission 410 of the SL-SIB, it may be performed at any time before the transmission 410 of the SL-SIB or before the transmission of the SCI.

Next, the transmitting terminal 401 may transmit a 1st stage (SCI) to the receiving terminal 402 through the PSCCH (460). Also, the transmitting terminal 401 may transmit a 2nd stage (SCI) to the receiving terminal 402 through the PSSCH ( 470 ). In this case, information related to resource allocation may be included in the 1st stage SCI, and other control information may be included in the 2nd stage SCI. Also, the transmitting terminal 401 may transmit data to the receiving terminal 402 through the PSSCH (480). In this case, the 1st stage (SCI), 2nd stage (SCI), and PSSCH may be transmitted together in the same slot. For the 1st stage (SCI) transmitted in the PSCCH and the 2nd stage (SCI) transmitted in the PSSCH, TS 38.212 may be referred to in the NR standard.

5 is a flowchart illustrating a method for a terminal to directly allocate/select a transmission resource for sidelink communication through sensing in sidelink communication according to an embodiment of the present disclosure.

Hereinafter, a method in which a terminal directly allocates/selects a transmission resource of sidelink communication through sensing in sidelink communication will be referred to as Mode 2. The method of Mode 2 may be referred to as a method of UE autonomous resource selection. In the Mode 2, the base station 503 may provide a transmission/reception resource pool for sidelink communication for V2X as system information, and the transmitting terminal 501 may allocate/select transmission resources according to a predetermined rule/standard. Unlike Mode 1 in which the base station is directly involved in resource allocation, in the embodiment of FIG. 5, the method of Mode 2 autonomously/directly sidelinks the transmitting terminal 501 based on the resource pool previously received through system information. There is a difference in that a resource for communication can be selected and data can be transmitted.

Referring to FIG. 5 , a transmitting terminal 501 may camp on a base station (cell) 503 ( 505 ). The camp on is, for example, a state in which a terminal in a standby state (RRC_IDLE) can select (or reselect) a base station (cell) as needed and receive system information or paging information. have. Also, referring to FIG. 5 , unlike FIG. 4 described above, in the case of Mode 2, when the transmitting terminal 501 is located within the coverage of the base station (cell) 503, the transmitting terminal 501 is the base station (cell) ) can camp on (503) (507). On the other hand, when the transmitting terminal 501 is located outside the coverage of the base station (cell) 503 , the transmitting terminal 501 may not camp on the base station (cell) 503 .

Meanwhile, when the receiving terminal 502 is located within the coverage of the base station (cell) 503 , the receiving terminal 502 may camp on the base station (cell) 503 ( 507 ). On the other hand, when the receiving terminal 502 is located outside the coverage of the base station (cell) 503 , the receiving terminal 502 may not camp on the base station (cell) 503 .

In the present disclosure, the receiving terminal 502 represents a terminal receiving data transmitted by the transmitting terminal 501 .

The transmitting terminal 501 and the receiving terminal 502 may receive a sidelink system information block (SL-SIB) from the base station 503 ( 510 ). The SL-SIB information includes sidelink resource pool information for transmission and reception in sidelink communication, parameter setting information for sensing operation, information for setting sidelink synchronization, or carrier information for sidelink transmission and reception operating at different frequencies. etc. may be included. The transmitting terminal 501 and the receiving terminal 502 may perform RRC setup for sidelink communication through the PC5 interface (515).

The difference between the embodiment of FIG. 4 and the embodiment of FIG. 5 is that, in the embodiment of FIG. 4 , the base station 503 and the terminal 501 operate in an RRC connected state, whereas in the embodiment of FIG. 5 , the terminal The point is that it can operate even in the idle mode 520 (in a state in which RRC is not connected). In addition, even in the RRC connected state 520 , the base station 503 may allow the transmitting terminal 501 to autonomously/directly allocate/select a transmission resource without directly participating in resource allocation. Here, the RRC connection between the terminal 501 and the base station 503 may be referred to as a Uu-RRC 520 . When data traffic for V2X communication is generated in the transmitting terminal 501, the transmitting terminal 501 sets a resource pool through the system information received from the base station 503, and the transmitting terminal 501 is set within the resource pool. Resources in the time/frequency domain may be directly allocated/selected through sensing ( 530 ). When the resource is finally allocated/selected, the allocated/selected resource is determined as a grant for sidelink transmission.

In the case of broadcast transmission, the transmitting terminal 501 may perform transmission without the RRC setting 515 for sidelink communication. Contrary to this, in the case of unicast or groupcast transmission, the transmitting terminal 501 may perform RRC connection with another terminal on a one-to-one basis. Here, the RRC connection between terminals may be referred to as a PC5-RRC 515 to be distinguished from the Uu-RRC. In the case of groupcast, the PC5-RRC 515 may be individually connected between the terminal in the group and the terminal. Referring to FIG. 5 , although the connection of the PC5-RRC 515 is illustrated as an operation after the transmission 510 of the SL-SIB, it may be performed at any time before the transmission 510 of the SL-SIB or before the transmission of the SCI.

Next, the transmitting terminal 501 may transmit a 1st stage (SCI) to the receiving terminal 502 through the PSCCH ( 550 ). Also, the transmitting terminal 401 may transmit a 2nd stage (SCI) to the receiving terminal 402 through the PSSCH (560). In this case, information related to resource allocation may be included in the 1st stage SCI, and other control information may be included in the 2nd stage SCI. Also, the transmitting terminal 501 may transmit data to the receiving terminal 502 through the PSSCH ( 570 ). In this case, 1st stage (SCI), 2nd stage (SCI), and PSSCH may be transmitted together in the same slot. For the 1st stage (SCI) transmitted in the PSCCH and the 2nd stage (SCI) transmitted in the PSSCH, TS 38.212 may be referred to in the NR standard.

Specifically, the downlink control information (SCI) used by the transmitting terminals 401 and 501 for sidelink communication to the receiving terminals 402 and 502 may include SCI format 1-A as a first stage (SCI). In addition, there may be SCI format 2-A or SCI format 2-B as a 2nd stage (SCI). In the second stage (SCI), SCI format 2-A includes information for PSSCH decoding when HARQ feedback is not used or when HARQ feedback is used and includes both ACK and NACK information. In contrast, SCI format 2-B may include information for PSSCH decoding when HARQ feedback is not used or when HARQ feedback is used and only NACK information is included. For example, SCI format 2-B may be limitedly used for groupcast transmission.

6 is a diagram illustrating an example of a mapping structure of physical channels mapped to one slot in sidelink communication according to an embodiment of the present disclosure.

Specifically, the mapping for PSCCH/PSSCH/PSFCH physical channels is illustrated in FIG. 6 . In the case of the PSFCH, when the HARQ feedback of the sidelink is activated in the upper layer, the resource in time of the PSFCH may be (pre-)configured with resource pool information. The physical sidelink feedback channel (PSFCH) is a channel carrying sidelink feedback control information (SFCI). For example, in sidelink communication, a receiving terminal may transmit an ACK or NACK to a transmitting terminal as an acknowledgment signal for sidelink data received by the receiving terminal. The SFCI may include such ACK/NACK information.

Here, the resource in the time domain in which information is transmitted in the PSFCH may be (pre-)configured to a value of one of every 0, 1, 2, and 4 slots. Here, '0' means that the PSFCH resource is not used. And 1, 2, and 4 may mean that PSFCH resources are configured for every 1, 2, and 4 slots, respectively. FIG. 6(a) shows a structure of a slot in which a PSFCH resource is not configured, and FIG. 6(b) shows an example of a structure of a slot in which a PSFCH resource is configured. PSCCH/PSSCH/PSFCH may be allocated to one or more subchannels in the frequency domain. For details on sub-channel allocation, refer to the description of FIG. 3 . Next, referring to FIG. 6 to describe the mapping in the time domain of PSCCH/PSSCH/PSFCH, one or more symbols before the transmitting terminal transmits PSCCH/PSSCH/PSFCH in the corresponding slot 601 are automatic gain control (AGC) may be used as a region 602 for Since the receiving terminal transmitting information in the PSFCH may be located adjacent to or far away from the transmitting terminal receiving information in the PSFCH, the information of the PSFCH may be received by the transmitting terminal with high reception power or with low reception power. can be received as Accordingly, the transmitting terminal may set the AGC range in order to receive information in the PSFCH with appropriate power. When the corresponding symbol(s) is used for the AGC, a method of repeating and transmitting signals of other channels in the corresponding symbol region may be considered. In this case, a portion of a PSCCH symbol or a PSSCH symbol may be considered for a signal that is repeated on another channel. Alternatively, the preamble may be transmitted in the AGC area. When the preamble signal is transmitted, there is an advantage that the AGC execution time can be further shortened compared to the method of repeatedly transmitting signals of other channels. When a preamble signal is transmitted for AGC, a specific sequence may be used as the preamble signal 602, and in this case, a sequence such as PSSCH DMRS (Demodulation Reference Signal), PSCCH DMRS, and CSI-RS (Channel State Information-Reference Signal) as the preamble. can be used. In the present disclosure, a sequence used as a preamble is not limited to the above-described example. Additionally, according to FIG. 6, control information related to resource allocation in the initial symbols of the slot is transmitted in the PSCCH 603 as the 1st stage SCI, and other control information is transmitted in the area 604 of the PSSCH as the 2nd stage SCI. . Data scheduled by the control information may be transmitted in the PSSCH 605 . In this case, the position in the time domain in which the 2nd stage SCI is transmitted may be mapped from the symbol in which the first PSSCH DMRS 606 is transmitted. A position in the time domain in which the PSSCH DMRS 606 is transmitted may be different in a slot in which the PSFCH is transmitted and a slot in which the PSFCH is not transmitted, as shown in FIGS. 6(a) and 6(b). The example of FIG. 6( a ) shows that the PSFCH 607 , which is a physical channel for transmitting the feedback control information, is located in the last part of the slot. It is possible to secure a predetermined free time (Guard) between the PSSCH 605 and the PSFCH 607 so that a terminal that has transmitted and received the PSSCH 605 can prepare to transmit or receive the PSFCH 607 . . In addition, after transmission and reception of the PSFCH 607 , an empty period (Guard) may be secured for a predetermined time.

7 is a sensing window necessary for the terminal to perform resource (re)selection and re-evaluation for resource allocation/selection in sidelink communication when the terminal operates in full sensing according to an embodiment of the present disclosure; A diagram for explaining a resource selection window.

Referring to FIG. 7 , when triggering for resource (re)selection is made at time n, the sensing window 701 may be defined as a time interval of [nT ₀ , nT _proc,0 ]. Here, T ₀ is the starting point of the sensing window and can be (pre-)configured as resource pool information. T ₀ may be defined as a positive integer in ms. This disclosure does not limit T ₀ to a specific value. In addition, T _proc,0 may be defined as a time required to process the sensed result. The present disclosure does not limit the value set to T _proc,0 to a specific value. For example, T _proc,0 may be defined as a positive integer in ms or in units of slots.

Next, when triggering for resource (re)selection is made at time n, the resource selection window 702 may be determined as [n+T ₁ , n+T ₂ ]. Here, T ₁ is a value of a unit of a slot and may be selected as a UE implementation for T ₁ ≤ T _proc,1 . T _proc,1 may be defined as a maximum reference value in consideration of the processing time required to select a resource. For example, T _proc,1 may be defined as a different value according to Subcarrier Spacing (SCS) in units of slots. The present disclosure does not limit the value set to T _proc,1 to a specific value. In addition, T ₂ is a value in units of slots and may be selected by the UE within a range that satisfies T _2min ≤ T ₂ ≤ Remaining Packet delay budget (PDB). Here, T _2min is to prevent the UE from selecting T ₂ having a too small value. Here, the T _2min value may be set by the upper layer to 'T _2min (prio _TX )' according to the priority (prio _TX ) and SCS of the transmitting terminal. The UE may select a transmission resource in the resource selection window 702 .

In the example of FIG. 7, triggering for resource (re-)selection is made at time n, and even after time n, the terminal continuously performs sensing to perform re-evaluation and pre-emption. An example in which triggering is performed at n' (n'>n) is shown. Specifically, when the UE determines that the selected resource is not suitable for transmission by continuously performing sensing after selecting a transmission resource by triggering the resource (re)selection at time n, time n'(n'>n) ) can trigger re-evaluation. Continuous sensing of the terminal can be performed by setting multiple sensing windows in parallel or sequentially. In addition, the pre-emption for resource change (reselection) is when the resource reserved by the terminal overlaps the resource reserved by another terminal, the priority of the resource reserved by the other terminal is high, and the interference to the resource is measured to be high At time point n' (n'>n), pre-emption may be triggered. In this case, the selected and reserved resource 703 by resource (re)selection at time n may be changed 706 to another resource. In the example of FIG. 7 , the sensing window 704 and the resource selection window 705 for the timing n' (n'>n) for triggering re-evaluation and pre-emption are shown together.

8 to 9 are diagrams for explaining a method of performing partial sensing in sidelink communication according to an embodiment of the present disclosure.

Unlike the full sensing in FIG. 7 , the embodiments of FIGS. 8 to 9 propose different methods for determining a slot for sensing when the terminal operates by partial sensing. However, it should be noted that the present disclosure is not limited to the methods presented through the embodiments of FIGS. 8 to 9 . Note that in the example of FIGS. 8 to 9 , when partial sensing is performed, the resource selection windows 801 and 901 may be determined as described with reference numeral 702 in the example of FIG. 7 .

로 도시되어 있다. 도 3을 통해 설명한 바와 같이

는 자원 풀에 속한 사이드링크 슬롯을 나타낼 수 있다. 이때 단말이 periodic-based partial sensing을 통해 센싱을 수행하는 슬롯은

로 결정될 수 있다. 여기서 벡터

는 Y개의 후보 슬롯(들)을 나타내며 만약 하나의 슬롯일 경우 도 8의 예에서와 같이 y로 표현될 수 있을 것이다. 또한 벡터

는 주기적인 reservation interval에 해당되는 값으로 하나 이상의 값이 포함될 수 있으며 만약 하나의 값인 경우에 도 8의 예에서와 같이

로 표현될 수 있을 것이다.

에 포함되는 값은 자원 풀에 (Pre-)configuration된 주기적인 reservation interval의 리스트인 sl-ResoureReservePeriodList로부터 결정될 수 있으며 다음과 같은 방법들이 고려될 수 있다. 하지만 본 개시가 아래의 방법 1-1 내지 방법 1-3에만 한정하지 않음에 주목한다. First, a method of performing partial sensing according to an embodiment of the present disclosure will be described with reference to FIG. 8 . The method presented in FIG. 8 is a method in which a slot in which a terminal performs sensing is determined based on a periodic reservation interval, and this method may be called periodic-based partial sensing. However, it is noted that the method presented through FIG. 8 may be referred to by other terms. Referring to FIG. 8 , candidate slot(s) for selecting Y (≥1) resources may be selected in the resource selection window 801 . In this case, the Y candidate slot(s) may be consecutively or non-consecutively selected in time in the resource selection window. The minimum value of Y can be (pre-)configured. The final selection of the Y value and which slot is selected may be determined by the terminal implementation. At this time, one of the Y candidate slot(s) is indicated by reference number 802.

is shown as As described with reference to FIG. 3

may indicate a sidelink slot belonging to the resource pool. At this time, the slot in which the terminal performs sensing through periodic-based partial sensing is

can be determined as vector here

denotes Y candidate slot(s), and if it is one slot, it may be expressed as y as in the example of FIG. 8 . Also vector

is a value corresponding to the periodic reservation interval, and may include one or more values.

can be expressed as

A value included in can be determined from sl-ResoureReservePeriodList , which is a list of (Pre-)configured periodic reservation intervals in the resource pool, and the following methods can be considered. However, it is noted that the present disclosure is not limited to methods 1-1 to 1-3 below.

Method 1-1: All values contained in sl-ResoureReservePeriodList are used

Method 1-2: Only a subset of the values included in sl-ResoureReservePeriodList is used

Method 1-3: The common divisor of the values contained in sl-ResoureReservePeriodList is used

에서 벡터

는 partial sensing을 수행하는 슬롯의 수를 결정하는 값으로

에 포함된 reservation interval에 의해서 센싱 슬롯들 간 간격이 결정될 수 있을 것이다. 도 8의 예에서는 k가 1, 2, 3, 4, 5인 경우가 도시 되었다.

를 결정하는 방법으로 다음과 같은 방법 2-1 내지 방법 2-6 중 적어도 하나가 고려될 수 있다. 하지만 본 개시가 아래의 방법에만 한정되지 않음에 주목한다. Also said

in vector

is a value that determines the number of slots performing partial sensing.

The interval between sensing slots may be determined by the reservation interval included in . In the example of FIG. 8 , the case where k is 1, 2, 3, 4, 5 is illustrated.

At least one of the following methods 2-1 to 2-6 may be considered as a method for determining It should be noted, however, that the present disclosure is not limited to the method below.

Method 2-1: Only one recent slot may be selected before the Y candidate slot(s) in consideration of the processing time for resource selection or before the time point 803 at which resource (re-)selection is triggered. For example, according to FIG. 8 , only a slot corresponding to reference number 804 may be selected as a slot for performing partial sensing on a candidate slot 802 for resource selection. In addition, as a slot for performing partial sensing with respect to the candidate slot 812 for resource selection, only a slot corresponding to reference number 814 may be selected.

Method 2-2: Only two recent slots may be selected before the Y candidate slot(s) in consideration of the processing time for resource selection or before the time 803 at which resource (re-)selection is triggered. For example, according to FIG. 8 , only slots corresponding to reference numerals 804 and 805 may be selected as slots for performing partial sensing on the candidate slot 802 . In addition, only slots corresponding to reference numbers 814 and 815 may be selected as slots for performing partial sensing on the candidate slot 812 .

로 결정될 수 있다. 예를 들어, 도 8에 따르면 참조 번호 (809)와 같이 sensing window [n-T₀, n-T_proc,0]가 설정된 경우 후보 슬롯 (802)에 대해서 sensing을 수행하기 위한 슬롯으로 참조 번호 (804), (805), 그리고 (806)에 해당되는 슬롯들이 선택될 수 있다. 그리고 후보 슬롯 (812)에 대해서 sensing을 수행하기 위한 슬롯으로 참조 번호 (814), (815), 그리고 (816)에 해당되는 슬롯들이 선택될 수 있다.Method 2-3: All slots in the configured sensing window [nT ₀ , nT _proc,0 ]

can be determined as For example, according to FIG. 8 , when the sensing window [nT ₀ , nT _proc,0 ] is set as shown in reference number 809, reference number 804, ( Slots corresponding to 805) and 806 may be selected. In addition, slots corresponding to reference numbers 814 , 815 , and 816 may be selected as slots for sensing the candidate slot 812 .

에서 하나의 reservation interval에 대해서 오직 하나의 슬롯만 선택되도록 k값이 결정되며 k값은 단말 구현에 의해서 결정될 수 있다. 또한 k의 최대값이 (pre-)configuration 될 수 있다. 예를 들어, 도 8에 따르면 후보 슬롯 (802)에 대해서 단말은 k=2로 결정하고 partial sensing을 수행하기 위한 슬롯으로 참조 번호 (805)에 해당되는 슬롯만 선택될 수 있다. 그리고 후보 슬롯 (812)에 대해서 단말은 k=2로 결정하고 partial sensing을 수행하기 위한 슬롯으로 참조 번호 (815)에 해당되는 슬롯만 선택될 수 있다.Method 2-4:

The value k is determined so that only one slot is selected for one reservation interval in , and the value k may be determined by the terminal implementation. Also, the maximum value of k can be (pre-)configured. For example, according to FIG. 8 , the terminal determines k=2 for the candidate slot 802 and only the slot corresponding to the reference number 805 may be selected as a slot for performing partial sensing. In addition, for the candidate slot 812, the terminal determines k=2 and only the slot corresponding to the reference number 815 can be selected as a slot for performing partial sensing.

Method 2-5: In a method in which the value of k is (pre-)configured, one or more k values may be (pre-)configured. For example, according to FIG. 8 , when k=1 and 2 are (pre-)configured with respect to the candidate slot 802, the slots corresponding to reference numbers 804 and 805 are slots for performing partial sensing. only can be selected. And when k=1 and 2 are (pre-)configured for the candidate slot 812, only slots corresponding to reference numbers 814 and 815 can be selected as slots for performing partial sensing. Here, a method in which the value of k is (pre-)configured to a different value according to a channel busy ratio (CBR), which is a measurement value indicating a channel congestion state, may be considered. In general, the more congested the channel, the higher the measured CBR value. In addition, as the channel becomes more congested, it is necessary to perform sensing better to prevent the selected resource from collided. Therefore, the higher the CBR value, the larger the k value needs to be used. The threshold of the CBR value for selection of the k value may be determined or (pre-)configured by the UE implementation, and in this case, the threshold of the CBR value may be determined as a different value according to priority.

Method 2-6: A value of k is determined by (pre-)configuration using a bitmap. For example, according to FIG. 8, when a bitmap having a length of 5 is used for the candidate slot 802 and, for example, when the bitmap is (pre-)configured as [10110], reference number ( Only slots corresponding to 805), 806, and 808 may be selected. And when a bitmap of length 5 is used for the candidate slot 812 and (pre-)configured as [10110], the slots for performing partial sensing are designated with reference numbers (815), (816), and (818). Only corresponding slots can be selected.

Referring to FIG. 9 , another method for performing partial sensing is presented according to an embodiment of the present disclosure. Unlike the periodic-based partial sensing of FIG. 8, the method presented in FIG. 9 is a method of performing sensing based on a continuous sensing window and may be called contiguous partial sensing. However, it is noted that the method presented through FIG. 9 may be referred to by other terms. Also, since partial sensing is performed in FIG. 9, a value whose length of the sensing window is smaller than the length of the sensing window in the full sensing of FIG. 7 may be used. Therefore, the sensing window 903 for contiguous partial sensing can be defined as a time interval of [n+T _A , n+T _B ]. At this time, as shown in FIG. 9(a), the values of T _A and T _B may be set to positive values based on the triggering time point n (902) for resource (re)selection, as shown in FIG. 9(b). Note that the values of T _A and T _B may be set to negative numbers as shown in . In addition, the values of T _A and T _B may be set to a value of 0.

10 is a diagram for describing a method in which re-evaluation or pre-emption is additionally performed when partial sensing or random selection is performed in sidelink communication according to an embodiment of the present disclosure.

Unlike the full sensing in FIG. 7 , when partial sensing or random selection is performed, the sensing window for re-evaluation and pre-emption needs to be set differently. According to FIG. 10, when triggering for re-evaluation or pre-emption occurs in slot n', the sensing window 1001 for re-evaluation and pre-emption is [n'-T _C , n'-T _proc,0 ]. As for the value, this disclosure does not limit the value set to T _proc,0 to a specific value. However, as described with reference to FIG. 7, it can be set to the same value as T _proc,0 defined in full sensing. In addition, the present disclosure does not limit the value set as T _C to a specific value. However, as the corresponding value, for example, the value of 32 slots can be used as T _C . And at this time, the resource selection window 1002 may be defined as a time interval of [n'+T ₁ , n'+T ₂ ]. Here, reference is made to the description of FIG. 7 of T ₁ and T ₂ . Therefore, when the resource selection mode is determined by partial sensing or random selection in the sidelink and re-evaluation or pre-emption is additionally performed, the terminal performs re-evaluation and pre-emption of the resource 1003 already selected or reserved. It can be reselected as another resource 1004 in the resource selection window 1002 through the sensing result in the sensing window 1001 for Note that, in the case of random selection, only a terminal capable of performing sensing can perform re-evaluation and pre-emption.

11A and 11B show inactive time (or off-duration) and active time (or on-duration) of DRX determined according to parameters configured for DRX when DRX operation is performed in sidelink communication according to an embodiment of the present disclosure; duration).

The UE may perform monitoring/decoding of a sidelink channel for control information and data information for data reception in a section corresponding to the active time of DRX. In contrast, monitoring/decoding of control information and data information for data reception may not be performed in a section corresponding to the inactive time of DRX. In sidelink communication, the control information includes, for example, 1st SCI, which is control information transmitted through the ^PSCCH , and ^2nd SCI, which is control information, which is transmitted through the PSSCH. Also, data information may be transmitted through the PSSCH. It can be assumed that control information and data information are always transmitted simultaneously in sidelink communication. Accordingly, a time point (slot) at which control information is received may be the same as a time point (slot) at which data information is received.

The following may be considered as parameters for determining inactive time and active time for DRX operation in sidelink communication. However, it is noted that in the present disclosure, the parameters for determining the inactive time and active time of DRX are not limited to the parameters presented below. Also note that some of the parameters of 1) to 7) below may not be used in DRX of sidelink communication.

DRX related parameters

1) drx-cycle:

Indicates a period to which DRX is applied, and a start position (drx-StartOffset) of the drx-cycle 1101 may be set. As shown in (a) and (b) of FIG. 11 , an interval between the inactive time 1110 and the active time 1111 may be set within the drx-cycle. In sidelink communication, a drx-cycle having a long cycle and a short cycle may be configured.

2) drx-onDurationTimer:

In the drx-cycle (1101), it is the active time (or on-duration) of DRX, and it may correspond to the active time (1110) of DRX until the drx-onDurationTimer (1102) operates and expires. The remaining section of the drx-cycle 1101 from the time when the drx-onDurationTimer 1102 expires may be the inactive time 1111 of the DRX. An example of a case in which only the drx-onDurationTimer 1102 is defined in the sidelink communication and the inactive time 1110 and the active time 1111 of DRX are operated is shown in FIG. 11( a ).

3) drx-InactivityTimer:

When the sidelink control information is detected/received 1103 before the drx-onDurationTimer 1102 expires in the drx-cycle 1101, the drx-InactivityTimer 1104 operates from the time when the control information is detected/received and expires The active time of DRX may be extended until (1110). The remaining section of the drx-cycle 1101 from the time when the drx-InactivityTimer 1104 expires may be the inactive time 1111 of the DRX. An example of a case in which drx-onDurationTimer 1102 and drx-InactivityTimer 1104 are defined in sidelink communication to operate inactive time 1110 and active time 1111 of DRX is shown in FIG. 11( b ).

4) drx-HARQ-RTT-Timer:

When retransmission is performed in sidelink communication, the UE may trigger a drx-HARQ-RTT (hybrid automatic repeat request-round trip time)-Timer 1105 within the active time 1111 of DRX (1103). The condition for triggering the drx-HARQ-RTT-Timer (1105) in sidelink communication is that sidelink control information is received or sidelink control information is received, and location information for retransmission is indicated in the sidelink control information (1 ^st SCI). In this case, the drx-HARQ-RTT-Timer 1105 may be applied until the next retransmission is received according to the corresponding information. When the drx-HARQ-RTT-Timer 1105 expires, the UE may operate in the active time 1111 of DRX in order to receive retransmission. In this case, the active time 1111 of DRX may be a period in which the drx-RetransmissionTimer 1106 operates. For details on this, see below. As described above, the drx-HARQ-RTT-Timer 1105 indicates initial transmission and retransmission indicated by ^{1st SCI} because location information (including information on the existence of retransmission resources) of the initial transmission and retransmission resources is indicated in 1st SCI. It may be assumed and defined as a time gap between resources or a time gap between retransmission resources. If it is indicated that there is no retransmission resource in the received ^1st SCI, the drx-HARQ-RTT-Timer 1105 may not operate. In sidelink communication, drx-onDurationTimer (1102), drx-InactivityTimer (1104), drx-HARQ-RTT-Timer (1105), and drx-RetransmissionTimer (1106) are defined, so that inactive time (1110) and active time ( 1111) is shown in FIG. 11( c ).

5) drx-RetransmissionTimer:

When retransmission is performed in sidelink communication, the drx-RetransmissionTimer 1106 may operate from the time when the drx-HARQ-RTT-Timer 1105 expires. Therefore, during the time period in which the drx-HARQ-RTT-Timer 1105 operates, the drx-RetransmissionTimer does not operate. Also, in sidelink communication, the drx-RetransmissionTimer 1106 may be determined as a fixed value of one slot or one subframe. In this case, the drx-RetransmissionTimer 1105 may not be defined. The present disclosure is not limited thereto. That is, in sidelink communication, drx-RetransmissionTimer may be set to a value of one or more slots or one or more subframes. Therefore, as in the example of FIG. 11C , the period in which the drx-RetransmissionTimer 1106 operates is set as the active time 1112 of the DRX to receive retransmission from the counterpart terminal (peer terminal). In addition, the remaining drx-cycle period is set as the inactive time 1113 of DRX, so that the terminal may not perform control and data information reception.

6) drx-SlotOffset:

When various subcarrier spacing (SCS) is supported, it may be used to adjust a start position to which DRX is applied in sidelink communication.

7) WUS (wake-up signal) cycle:

When the WUS for power saving of the terminal is used in sidelink communication, a WUS cycle may be set. It is assumed that the WUS is transmitted according to the WUS cycle, and the terminal may perform monitoring for the WUS at the location where the WUS is transmitted ( 1107 ). Referring to FIG. 11( d ), an example in which an inactive time and an active time of DRX are determined by using a wake-up signal (WUS) is shown. As in FIG. 11(d), when the WUS indicates that the UE does not wake up in reference number 1107, the UE does not operate the drx-onDurationTimer 1102 in the drx-cycle 1101 and all drx-cycle sections are inactive of DRX. It may be set to time (1110). On the other hand, in 1107, when the WUS indicates that the terminal is waking up, the terminal performs the same operation as in the example of FIG. 11(a), FIG. 11(b), or FIG. 11(c) according to the set DRX parameter. can

According to the above description, active time (or on-duration) in DRX may be defined as the following condition. For example, when the DRX cycle is configured in sidelink communication, the active time (or on-duration) may correspond to a time interval in which drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimer operates.

As mentioned above, some of the above parameters may not be used in sidelink DRX. Or other parameters may be additionally considered. Note that this may vary depending on the transmission method of broadcast, unicast, and groupcast in sidelink communication. Also, in the present disclosure, the method of setting the parameter information is not limited to a specific method. Corresponding information may be (pre-)configuratione, or in the case of unicast, may be configured through PC5-RRC or sidelink MAC-CE.

The present disclosure proposes the above-described Mode2 sensing and resource selection method (refer to FIGS. 7 to 10 ) of the terminal when DRX is operated in sidelink communication (refer to the embodiment of FIG. 11 ). As described above, the UE may not perform monitoring/decoding of control information and data information in a time period set as inactive time because DRX is applied in sidelink communication. Here, the control information may include ^1st SCI and ^2nd SCI information of the sidelink. As described above, Mode2 sensing in sidelink communication (that is, a method in which the UE directly allocates/selects the transmission resource of sidelink communication through sensing) is an operation in which the UE monitors the sidelink channel. Decoding of the PSCCH (Physical Sidelink Control Channel) (In other words, decoding of 1st SCI) and SL- ^RSRP (Sidelink Reference Signal Received Power) measuring operation. If, in sidelink communication, monitoring/decoding of control information for data reception (1 ^st SCI and 2 ^nd SCI) is not allowed in the section set as the inactive time of DRX, but control information for the purpose of sensing for resource selection (1 ^st SCI) monitoring/decoding is allowed, since the sensing can be performed even in the inactive time of DRX, the terminal performing DRX in sidelink communication performs the sensing operations described with reference to FIGS. 7 to 10. Problem may not occur. However, in the case where monitoring/decoding of control information for data reception as well as monitoring/decoding of control information (1 ^st SCI) for the purpose of sensing in the section set as inactive time of DRX in sidelink communication is not allowed, Mode2 A problem may occur in the sensing operation. In the first embodiment 1 below, a solution method and a terminal operation according to an embodiment of the present disclosure for a case in which a problem may occur in the Mode2 sensing operation is presented. In addition, when a transmitting terminal (peer terminal) that transmits sidelink data to a receiving terminal performing a DRX operation performs Mode2 sensing to select a resource, the corresponding receiving terminal must be able to receive data, so the terminal operation in consideration of this must be defined There is a need. In the following embodiments, a solution method and terminal operation for the corresponding case are presented.

<First embodiment>

In the first embodiment, the control information (1 st SCI and 2 nd SCI) for the purpose of sensing as well as monitoring/decoding of control information ((1 ^st SCI and 2 ^nd SCI)) for data reception in the section set as the inactive time of DRX in the ^sidelink SCI) monitoring / decoding is also not allowed, Mode2 sensing and resource selection operation method is presented. In this case, the terminal cannot perform sensing in a section set as the inactive time of DRX in sidelink communication. If the terminal performs sidelink DRX and needs to perform Mode2 sensing, the sensing period (slot) (refer to the sensing period of FIGS. 7 to 10 ) overlaps with the inactive time of DRX. The same teacher methods can be considered. Note that the present disclosure is not limited to the following sensing methods. It is also noted that two or more of the following sensing methods may be used in combination.

Sensing method 1: The sensing period (slot) is adjusted to the active time of the sidelink DRX so that a previously set sensing period (slot) can be secured, and the terminal performs sensing in the corresponding sensing period (slot).

Sensing method 2: The UE performs sensing only in a section (slot) corresponding to the active time of sidelink DRX in a previously set sensing section (slot).

According to the sensing method 2, sensing may be performed only when at least a part of the previously set sensing period (slot) corresponds to the active time of the sidelink DRX. If all of the previously set sensing periods (slots) correspond to the inactive time of the sidelink DRX, sensing cannot be performed. In order to solve this problem, the UE may adjust the resource (re-)selection triggering time n to include a part of the sensing period (slot) within the active time of the sidelink DRX. The UE may check whether a part of the sensing period (slot) is included in the active time of the sidelink DRX based on the DRX-related configuration information.

Sensing method 3: The terminal does not perform sensing. In this case, random selection may be used for resource selection.

Sensing method 4: This is a method in which the sensing method 2 and the sensing method 3 are combined. For details, refer to other embodiments (Examples 2 to 3) to be described later.

Sensing method 5: An already set sensing period (slot) is set as the active time of the sidelink DRX, and the terminal performs sensing in the set sensing period (slot).

According to the sensing method 5, monitoring/decoding of control information (1 ^st SCI) is allowed only for the purpose of sensing for resource selection that the sensing period (slot) is set as the active time of sidelink DRX, and control information for data reception It may be determined that monitoring/decoding of ((1 ^st SCI and 2 ^nd SCI)) is not allowed. Alternatively, it may be determined that monitoring/decoding of control information (1 ^st SCI and 2 ^nd SCI) for data reception as well as control information (1 ^st SCI) is allowed for a sensing purpose for resource selection. If the sensing method 5 allows decoding of control information ((1 ^st SCI and 2 ^nd SCI)) for data reception, the corresponding information may be additionally indicated for data transmission/reception between terminals in sidelink communication. In this case, various instruction methods may be used. In general, an instruction for matching the sidelink DRX wake-up time may be provided through SCI (1 ^st SCI or 2 ^nd SCI). Alternatively, in unicast, the corresponding indication may be provided through PC5-RRC or sidelink MAC CE. However, the method of indicating through SCI has the advantage that it can be used in broadcast, groupcast, and unicast. However, in the sensing method 5, the indication method for matching the sidelink DRX wake-up time is that the sensing period (slot) is set as the active time of the sidelink DRX control information (1 ^st SCI) only for the purpose of sensing for resource selection. Note that the decoding of is allowed and monitoring/decoding of control information ((1 ^st SCI and 2 ^nd SCI)) for data reception may be supported even when it is determined not to allow.

12 is a view for explaining the sensing method 1 of the terminal according to an embodiment of the present disclosure.

Referring to FIG. 12( a ), according to an embodiment of the present disclosure, when the full sensing of FIG. 7 , the contiguous partial sensing of FIG. 9 , and the partial sensing and random selection of FIG. 10 are performed, re-evaluation and pre- A case in which the sensing section set for performing the emption is adjusted by the sensing method 1 is exemplified. According to the sensing method 1, the extension of the sensing period may be possible only in the period set as the DRX active time. In FIG. 12( a ), an example of a case in which a sensing period 1200 is set and a part of the sensing period overlaps with the DRX inactive time ( 1202 ) is shown. It should be noted that FIG. 12( a ) is an example in which DRX active time and inactive time are configured, and the active time and inactive time of DRX may be generated in various ways according to DRX parameters. In FIG. 12( a ), since a part of the sensing period 1200 is set as the inactive time period 1202 of the DRX and sensing cannot be performed in the corresponding period, sensing is performed to further guarantee the sensing period according to the sensing method 1 . The section may be adjusted and operated as extended as reference number 1204 . In this case, the extended sensing period may be configured in the active time 1203 of DRX. If the active time period of DRX is discontinuous, the extended sensing period may also be configured discontinuously.

Referring to FIG. 12( b ), a case in which a sensing period (slot) set for performing periodic-based partial sensing of FIG. 8 is adjusted by the sensing method 1 according to an embodiment of the present disclosure An example was shown. When DRX is configured and not operated in the sidelink, a sensing interval (slot) configured to perform periodic-based partial sensing may be determined by using the methods described in the embodiment of FIG. 8 . However, in sidelink communication, if a period (slot) for performing sensing by operating DRX overlaps with an inactive time of DRX, a sensing period (slot) may be determined according to sensing method 1 . When DRX is set and not operated in sidelink communication, the sensing slot 1200 of FIG. 12(b) is set and the terminal may perform sensing in the corresponding slot 1200. However, in contrast, FIG. 12(b) As in , when the period (slot) in which DRX is operated and sensing is performed in sidelink communication overlaps the inactive time of DRX (1200), the terminal cannot perform sensing in the overlapped period (1200). In this case, according to the sensing method 1, the sensing slot 1203 is adjusted to be set in the active time period 1201 of the DRX instead of being set in the overlapping period 1200 in FIG. 12(b). sensing may be possible. Therefore, when the sensing method 1 is applied to periodic-based partial sensing, it can be interpreted as a method in which a sensing period (slot) is limited to be set in the active time of the DRX.

In addition, according to the sensing method 5, active time (or on-duration) in DRX may be set as the following condition.

When the DRX cycle is configured in sidelink communication, the setting condition of active time (or on-duration) may include at least one of the following conditions.

Condition 1: When drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimer is running

Condition 2: When the sensing section (slot) operates (when sensing is performed in the sensing section (slot))

In addition, in the sensing method 5, 'the case where the DRX cycle is set in the sidelink communication' may be interpreted as 'the case where the DRX is performed in the sidelink communication'. In addition, the 'when the sensing period (slot) is operating' may be interpreted as a case in which the timer for the DRX active time is running in the corresponding sensing period (slot). Note that the methods of the first embodiment can be applied to all of the sensing methods described with reference to FIGS. 7 to 10 .

<Second embodiment>

The second embodiment proposes a terminal operation when the sensing methods 2 to 4 described in the first embodiment are applied to a sensing interval (slot) set for performing periodic-based partial sensing of FIG. 8 . As described above, according to the sensing method 2, sensing can be performed only when at least a part of the previously set sensing period (slot) corresponds to the active time of the sidelink DRX. If all of the previously set sensing periods (slots) correspond to the inactive time of the sidelink DRX, sensing cannot be performed. Therefore, in order for the sensing method 2 to be always operable, it is necessary to apply the sensing method 3 in the above case or to selectively apply the sensing method 2 and the sensing method 3 according to a predetermined condition like the sensing method 4 .

13 is a view for explaining the sensing method 2 to the sensing method 4 of the terminal according to an embodiment of the present disclosure.

(1300)로부터 partial sensing을 수행하기 위한 슬롯으로 X=2개의 모니터링 슬롯(1301과 1302)이 설정되었지만 해당 슬롯이 모두 사이드링크 DRX의 inactive time(1310)에 포함된 경우가 도시되어 있다. 도 13(a)에서와 같이 X(≥1)개의 모니터링 슬롯이 periodic-based partial sensing을 수행하기 위해 설정되었지만 해당 슬롯이 모두 사이드링크 DRX의 inactive time에 포함되어 사용 가능한 센싱 구간(슬롯)이 확보되지 않는 경우에는 상기 센싱 방법 3과 같이 단말은 센싱을 수행하지 않고 자원 선택에 random selection이 사용될 수 있다.Referring to FIG. 13A , as described with reference to FIG. 8 according to an embodiment of the present disclosure, one of Y candidate slots selected to perform periodic-based partial sensing.

A case in which X=2 monitoring slots 1301 and 1302 are set as slots for performing partial sensing from 1300, but all of the slots are included in the inactive time 1310 of the sidelink DRX is shown. As shown in FIG. 13(a), X (≥1) monitoring slots are set to perform periodic-based partial sensing, but all of the corresponding slots are included in the inactive time of the sidelink DRX to secure a usable sensing period (slots). If not, as in the sensing method 3, the UE does not perform sensing and random selection may be used for resource selection.

(1300)로부터 partial sensing을 수행하기 위한 슬롯으로 X=3개의 모니터링 슬롯(1301, 1302,1303)이 설정되었지만 그 중 1개의 슬롯(1302)은 사이드링크 DRX의 inactive time(1310)에 포함되고 다른 두개의 슬롯(1301, 1303)은 사이드링크 DRX의 active time에 포함된 경우가 도시되어 있다. 도 13(b)에서와 같이 X(≥1)개의 모니터링 슬롯이 periodic-based partial sensing을 수행하기 위해 설정되었지만 오직 Y(1≤Y≤X)에 해당되는 슬롯이 사이드링크 DRX의 active time에 포함되어 센싱에 사용 가능한 경우에 다음과 같은 상기 센싱 방법2가 사용되거나 상기 센싱 방법4가 고려될 수 있다. 구체적으로 상기 센싱 방법2에 따르면 단말은 Y개의 이용 가능한 센싱 슬롯에서 periodic-based partial sensing을 수행하고 이용할 수 없는 X-Y(≥0)개의 슬롯이 발생될 경우에 해당 슬롯은 센싱에 이용되지 않을 것이다. Referring to FIG. 13B , as described with reference to FIG. 8 according to an embodiment of the present disclosure, one of Y candidate slots selected to perform periodic-based partial sensing is

X=3 monitoring slots 1301, 1302, and 1303 are set as slots for performing partial sensing from 1300, but one slot 1302 is included in the inactive time 1310 of the sidelink DRX and the other The case where the two slots 1301 and 1303 are included in the active time of the sidelink DRX is illustrated. As shown in FIG. 13(b), X (≥1) monitoring slots are configured to perform periodic-based partial sensing, but only Y (1≤Y≤X) slots are included in the active time of the sidelink DRX. In the case where it can be used for sensing, the following sensing method 2 may be used or the sensing method 4 may be considered. Specifically, according to the sensing method 2, the terminal performs periodic-based partial sensing on Y available sensing slots, and when XY (≥0) unusable slots occur, the corresponding slots will not be used for sensing.

Next, the sensing method 4 is a method for determining whether the sensing method 2 or the sensing method 3 is selected according to what condition. Specifically, according to sensing method 4, if Y is greater than or equal to N% of X, periodic-based partial sensing is performed in Y slots by sensing method 2; otherwise, sensing is not performed by sensing method 3 Random selection may be used for resource selection without Here, for example, N=100 means when X=Y (that is, when all configured monitoring slots are available), and if at least one of the X monitoring slots that cannot be sensed is generated by the inactive time of the sidelink DRX, the It may mean selecting the sensing method 3 . In the sensing method 4, the N value may be fixed to a specific value, and the N value may be configurable. When the value of N is configurable, a (pre-)configuration method may be used, and when PC5-RRC is available such as unicast, a method of configuring through PC5-RRC or sidelink MAC CE may be considered. Alternatively, a method in which the N value is indicated by being included in the SCI (1 ^st SCI or 2 ^nd SCI) may be considered. In addition, when the N value is configurable, a method in which the N value is set in association with CBR (Channel Busy Ratio) may be considered. In sidelink communication, the UE may measure the CBR, and the higher the channel congestion, the higher the measured CBR value. In general, the more congested the channel is, the better the sensing can be to avoid resource selection conflicts. Therefore, it can be supported so that the N value can be set differently according to a CBR value (or a CBR level, a measured CBR value may be mapped to a defined CBR level). Specifically, the larger the CBR value, the smaller the value of N can be set, so that the sensing method 2 can be adjusted to be selected more frequently by the sensing method 4 . Also, in this method, the threshold for the CBR value that determines the N value may be set differently according to priority. And the threshold for the CBR value for determining the N value is determined by the terminal implementation, or a (pre-)configuration method may be considered.

In the present disclosure, as shown in FIG. 13(b), X (≥1) monitoring slots are set to perform periodic-based partial sensing, but only slots corresponding to Y (1≤Y≤X) are active in the sidelink DRX. When included in time and available for sensing, one of the sensing method 2 and the sensing method 3 is selected by the sensing method 4, and as described above, only the case where Y is N% or more of X is not limited. For example, as another condition, a case in which active time is N% or more in drx-cycle may be considered. Here, the active time can be limited only to the active time determined by drx-onDurationTimer. This is because drx-InactivityTimer or drx-RetransmissionTimer may or may not be operated depending on the situation. In this case, if the active time in the drx-cycle is N% or more, the sensing method 2 is applied, otherwise, the sensing method 3 may be applied. This method is based on the fact that it is difficult to perform sensing when active time is not secured in the drx-cycle.

<Third embodiment>

In the third embodiment, when the sensing method 2 to the sensing method 4 described in the second embodiment perform the full sensing of FIG. 7, the contiguous partial sensing of FIG. 9, and the partial sensing and random selection of FIG. -Suggests a terminal operation for a case where it is applied to a sensing section set to perform evaluation and pre-emption. As described above, according to the sensing method 2, the terminal may perform sensing only when at least a part of the previously set sensing period (slot) corresponds to the active time of the sidelink DRX. If all of the previously set sensing periods (slots) correspond to the inactive time of sidelink DRX, the UE cannot perform sensing. Therefore, in order for the sensing method 2 to be always operable, it is necessary to apply the sensing method 3 or selectively apply the sensing method 2 and the sensing method 3 according to a predetermined condition like the sensing method 4 in the above case. .

14 is a view for explaining the sensing methods 2 to 4 according to an embodiment of the present disclosure.

Referring to FIG. 14( a ) , re-evaluation and pre- evaluation when full sensing of FIG. 7 , contiguous partial sensing of FIG. 9 , and partial sensing and random selection of FIG. 10 are performed according to an embodiment of the present disclosure A case in which all of the sensing periods 1401 configured to perform emption are included in the inactive time 1410 of the sidelink DRX is illustrated. As shown in FIG. 14( a ), when a sensing period (slot) of length X is set, but the corresponding slots are all included in the inactive time of the sidelink DRX, and a usable sensing period (slot) is not secured, the sensing method 3 and Random selection may be used for resource selection without performing sensing together.

Referring to FIG. 14(b) , according to an embodiment of the present disclosure, when the full sensing of FIG. 7, the contiguous partial sensing of FIG. 9, and the partial sensing and random selection of FIG. 10 are performed, re-evaluation and pre- A case in which only a part of the sensing period 1401 configured to perform emption is included in the inactive time 1410 of the sidelink DRX and the other region is included in the active time 1411 of the sidelink DRX is illustrated. As in FIG. 14(b), when a sensing period (slot) of length X is set, but only a sensing period (slot) corresponding to length Y (Y≤X) is included in the active time of the sidelink DRX and is available for sensing In the following, the sensing method 2 may be used or the sensing method 4 may be considered. Specifically, according to the sensing method 2, the terminal performs monitoring only in the sensing slot corresponding to the Y length, and when an unusable area of XY (≥ 0) length occurs, the corresponding area will not be used for sensing. Next, the sensing method 4 is a method of determining whether the sensing method 2 or the sensing method 3 is selected according to a predetermined condition. Specifically, according to the sensing method 4, if Y is N% or more of X, sensing is performed in Y slots by sensing method 2, and if not, sensing is not performed by sensing method 3 but random selection for resource selection this can be used Here, N=100 means when X=Y (that is, when all configured slots are available), and if there is an area in which sensing is impossible among sensing sections (slots) of length X due to the inactive time of sidelink DRX, sensing method 3 may mean choosing In the sensing method 4, the N value may be fixed to a specific value, and the N value may be configurable. When the value of N can be set, a (pre-)configuration method may be used, and when PC5-RRC is available such as unicast, a method of configuring through PC5-RRC or sidelink MAC CE may be considered. Alternatively, a method in which the N value is indicated by being included in the SCI (1 ^st SCI or 2 ^nd SCI) may be considered. In addition, when the N value can be set, a method in which the N value is set in association with the CBR may be considered. In the sidelink, the UE may measure the CBR, and the higher the channel congestion, the higher the measured CBR value. In general, the more congested the channel is, the better the sensing can be to avoid resource selection conflicts. Therefore, it can be supported so that the N value can be set differently according to the CBR value (or the CBR level, the measured CBR value can be mapped to the defined CBR level). Specifically, the larger the CBR value, the smaller the N value can be set, so that the sensing method 2 can be adjusted to be selected more frequently by the sensing method 4 . Also, in this method, the threshold for the CBR value that determines the N value may be set differently according to priority. And the threshold for the CBR value for determining the N value is determined by the terminal implementation, or a (pre-)configuration method may be considered. In the present disclosure, as in FIG. 14(b), a sensing period (slot) of length X is set, but only a sensing period (slot) corresponding to length Y (Y≤X) is included in the active time of the sidelink DRX for sensing. If available, one of the sensing method 2 and the sensing method 3 is selected by the sensing method 4 when available. For example, as another condition, a case in which active time is N% or more in drx-cycle may be considered. Here, the active time can be limited only to the active time determined by drx-onDurationTimer. This is because drx-InactivityTimer or drx-RetransmissionTimer may or may not be operated depending on the situation. In this case, if the active time in the drx-cycle is N% or more, the sensing method 2 is applied, otherwise, the sensing method 3 may be applied. This method is based on the fact that it is difficult to perform sensing when active time is not secured in the drx-cycle.

<Fourth embodiment>

In the fourth embodiment, the transmitting terminal (peer terminal) transmitting sidelink data to the receiving terminal performing the DRX operation is a method in which the above-described Mode2 sensing (that is, the terminal directly allocates/selects the transmission resource of the sidelink communication through sensing) ) to select a resource, since the corresponding receiving terminal must be able to receive data, it is necessary to define a terminal operation in consideration of this. In other words, unlike a case in which DRX is not operated in sidelink communication, when DRX is operated in sidelink communication, an operation for determining a resource selection window by the UE needs to be defined differently. Specifically, if terminal B transmits sidelink data to terminal A during a period in which terminal A operates in DRX inactive time in sidelink communication, terminal A may not receive it. Therefore, when a transmitting terminal (peer terminal) that transmits sidelink data to a receiving terminal performing DRX performs the Mode2 sensing to select a resource, it is necessary to determine a resource selection window so that the receiving terminal can receive transmission data. have. The following methods may be considered as a terminal operation for this. Note that the present disclosure is not limited only to the following resource selection methods. It is also noted that two or more of the resource selection methods below may be used in combination.

Resource selection method 1: The resource selection window is adjusted to the active time of sidelink DRX, and the UE selects a resource in the corresponding section (slot).

According to the resource selection method 1, even when the resource selection window [n+T ₁ , n+T ₂ ] described with reference to FIG. 7 is adjusted to the active time of the sidelink DRX, T ₂ satisfies the Remaining Packet delay budget (PDB). The terminal will be able to select within the specified range. In addition, according to the resource selection method 1, the receiving terminal needs to select a resource only in the active time of the sidelink DRX operation and DRX compared to when the terminal determines the resource selection window when the sidelink DRX is not operated. Because it can, the length of the resource selection window determined by the terminal can be adjusted. If the resource selection window is adjusted to the active time of DRX due to the PDB, a problem may occur in which a selectable resource candidate cannot be secured. In order to solve this problem, the UE may be able to adjust the resource (re-)selection triggering time n so that the resource selection window includes at least the active time of the sidelink DRX.

In the resource selection method 1, if the resource selection window is adjusted to the active time of sidelink DRX and there is no selectable PSSCH resource, the transmitting terminal may select a transmission resource from the exceptional pool. In this case, the exceptional pool may be understood as a resource pool in which sidelink transmission/reception is always possible independently of sidelink DRX. In addition, the exceptional pool may be understood as a resource pool that is preset in advance in addition to the sidelink resource pool through the (pre-)configuration described above to enable sidelink transmission and reception independently of DRX. Also, as another example, if the available resources for sidelink communication are sufficient, it may be possible to allocate resources to the UE using a grant scheme configured to ensure resource allocation through the exceptional pool. In addition, resource selection in the exceptional pool may be performed by random selection without the UE performing sensing. Even during resource selection using the exceptional pool, the above-described operation in which the transmitting terminal transmits the SCI including resource allocation information, etc. to the receiving terminal through the PSCCH may be performed in the same manner. The exceptional pool may be set through at least one of higher layer signaling information such as RRC information and SIB information, or L1 signaling information such as DCI and SCI information. As described above, in the present disclosure, the exceptional pool can be used when there is no resource that the UE can select or reselect within the resource selection window.

Resource selection method 2: The UE determines the resource selection window without considering the sidelink DRX, and selects the resource only in the region corresponding to the active time of DRX in the corresponding section (slot).

According to the resource selection method 2, the resource selection window [n+T ₁ , n+T ₂ ] may be determined as described with reference to FIG. 7 . In addition, according to the resource selection method 2, selectable resource candidates are generated only when at least a part of the resource selection window corresponds to the active time of the sidelink DRX. If all resource selection windows correspond to the inactive time of sidelink DRX, there may be a problem that there are no selectable resource candidates. In order to solve this problem, the UE may be able to adjust the resource (re-)selection triggering time n so that the resource selection window includes at least the active time of the sidelink DRX.

In the resource selection method 2, if a resource needs to be selected only in the region corresponding to the DRX active time in the resource selection window, and there is no selectable PSSCH resource, the transmitting terminal may select a transmission resource from the exceptional pool. . In this case, the exceptional pool can be understood as a pool in which sidelink transmission/reception is always possible independently of sidelink DRX. In addition, the exceptional pool may be understood as a resource pool that is preset in advance in addition to the sidelink resource pool set through the (pre-)configuration, for example, to enable sidelink transmission and reception independently of DRX. Also, as another example, if the available resources for sidelink communication are sufficient, it may be possible to allocate resources to the UE using a grant scheme configured to ensure resource allocation through the exceptional pool. In addition, resource selection in the exceptional pool may be performed by random selection without performing sensing. Even during resource selection using the exceptional pool, the above-described operation in which the transmitting terminal transmits the SCI including resource allocation information, etc. to the receiving terminal through the PSCCH may be performed in the same manner. The exceptional pool may be set through at least one of higher layer signaling information such as RRC information and SIB information, or L1 signaling information such as DCI and SCI information. As described above, in the present disclosure, the exceptional pool may be used when there is no resource selectable or reselectable by the UE in the resource selection window.

Resource selection method 3: The UE determines the resource selection window without considering the sidelink DRX, and the corresponding section (slot) is defined as the active time of the sidelink DRX, and the UE selects a resource in the determined resource selection window area.

According to the resource selection method 3, the resource selection window is set as the active time of the sidelink DRX is controlled for the purpose of sensing for resource selection as well as control information for data reception ((1 ^st SCI and 2 ^nd SCI)) It may be determined that monitoring/decoding of information (1 ^st SCI) is permitted. According to the resource selection method 3, corresponding information may be additionally indicated for data transmission/reception between terminals in sidelink communication. In this case, various instruction methods may be used. In general, an instruction for matching the sidelink DRX wake-up time may be made through SCI (1 ^st SCI or 2 ^nd SCI). Alternatively, in unicast, the corresponding indication may be made through PC5-RRC or sidelink MAC CE. However, the method of indicating through SCI has the advantage that it can be used in broadcast, groupcast, and unicast.

In addition, according to the resource selection method 3, active time (or on-duration) in DRX may be defined as the following condition.

When the DRX cycle is configured in sidelink communication, the setting condition of active time (or on-duration) may include at least one of the following conditions.

Condition 1: When drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimer is activated or

Condition 2: When the resource selection window operates (when the resource selection window for resource selection is set)

In addition, in the resource selection method 3, 'the case where the DRX cycle is set in the sidelink communication' may be interpreted as 'the case where the DRX is performed in the sidelink communication'. In addition, the 'when the resource selection window operates' may be interpreted as a case in which the corresponding resource selection window is running a timer for DRX active time.

When periodic-based partial sensing is performed as shown in FIG. 8 , Y (≥1) candidate slots may be selected in the resource selection window 801 . In this case, the Y candidate slots may be continuously or non-contiguously selected in the time domain in the resource selection window. The minimum value of Y can be (pre-)configured. The final selection of the Y value and which slot is selected may be determined by the terminal implementation. If the sidelink DRX is configured and operated, when Y (≥1) candidate slots are selected in the resource selection window 801, it needs to be selected from the slot corresponding to the active time of the sidelink DRX.

15 is a flowchart illustrating a terminal operation for sensing and resource selection when DRX is performed in sidelink communication according to an embodiment of the present disclosure.

Specifically, according to FIG. 15 , for example, four terminals UE1 to UE4 performing transmission/reception in the sidelink according to an embodiment of the present disclosure are illustrated. In FIG. 15 , UE 1 is a terminal to perform sidelink data transmission, that is, PSSCH transmission to UE2, and in this case, UE2 is a terminal performing sidelink DRX. As described in Example 4 above, when UE 1 transmits sidelink data to UE 2 during a period in which UE 2 operates in DRX inactive time in sidelink communication, UE 2 may not receive it. Therefore, in step 1501, the peer terminal UE1 that transmits the sidelink data to the UE2 performing DRX performs Mode2 sensing to select a resource, so that the receiving terminal UE2 can receive the transmission data through the resource selection window need to decide. Although not shown, terminals performing transmission/reception in the sidelink may receive DRX configuration and DRX-related parameters configured in various ways. For example, (pre-)configuration or, in the case of unicast, corresponding information may be configured through PC5-RRC or MAC CE. In step 1502, UE1 may select a resource in the resource selection window determined in step 1501 and transmit sidelink data to UE2 through PSCCH/PSSCH. For detailed methods on this, refer to Example 4 above. In the fourth embodiment, the operation of the present disclosure focusing on the case of Mode2 is shown in FIG. 15, but even in Mode1, when the base station allocates resources to the UE1, if the receiving terminal UE2 is performing DRX, the base station It is necessary to identify DRX state information and allocate resources to the DRX active time of UE2. To this end, the base station needs to know the DRX state information (such as whether DRX is set and DRX related parameters) of the terminal. As described with reference to FIG. 4 , in the case of Mode 1, the terminal may additionally signal information that can help the base station to perform scheduling to the base station. This can be done using RRC messages or MAC CEs. The present disclosure does not limit the method of indicating corresponding information thereto. Also, the corresponding information may be named UEAssistanceInformation. The base station may set the DRX state information to be cell common, and the base station may assume the corresponding setting. On the other hand, when the base station cannot adjust the corresponding setting (for example, when the corresponding information is set through PC5-RRC or MAC CE in the case of unicast), the terminal includes DRX status information in UEAssistanceInformation to the base station can be directed to In the case of Mode1, the base station should perform Mode1 scheduling by identifying DRX configuration information of the terminal, and the terminal can expect that the base station performs Mode1 scheduling with DCI accordingly. Meanwhile, in FIG. 15 , when UE2 is a terminal performing sidelink DRX, sensing may not be possible in the inactive time of sidelink DRX. As described in Embodiments 1 to 3 above, when all sensing periods (slots) are inactive times of DRX, UE2 may not be able to perform a sensing operation. Therefore, as in step 1503, UE2 does not perform sensing or the sensing period (slot) needs to be determined in the active time of DRX. When the sensing period (slot) is determined as the active time of DRX, UE2 may monitor the PSCCH (1 ^st SCI) of another UE (UE3) in the sensing period as in step 1504. For detailed methods on this, refer to Examples 1 to 3 above. For reference, in FIG. 15 , UE3 is a terminal to perform sidelink data transmission, that is, PSSCH transmission to UE4, and in this case, UE4 is a terminal that does not perform sidelink DRX. In this case, UE3 determines a resource selection window in step 1505 without considering the DRX of the receiving terminal differently from the operation of UE1 in step 1501, selects a resource, and transmits sidelink data to UE4 through PSCCH/PSSCH.

In order to perform the above embodiments of the present disclosure, a transmitter, a receiver, and a processor of the terminal and the base station are shown in FIGS. 16 and 17, respectively. In the above embodiments, various methods for sensing and resource selection by the terminal in sidelink communication are shown, and in order to perform this, a receiver, a processor, and a transmitter of the base station and the terminal must operate according to the embodiment, respectively.

Specifically, FIG. 16 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure.

As shown in FIG. 16 , the terminal of the present disclosure may include a terminal receiving unit 1600 , a terminal transmitting unit 1604 , and a terminal processing unit 1602 . The terminal receiving unit 1600 and the terminal may collectively refer to the transmitting unit 1604 as a transceiver in an embodiment of the present disclosure. The terminal processing unit 1602 controls a sensing operation and/or a resource selection operation according to the embodiments of the present disclosure, and the terminal processing unit 1602 may be referred to as a controller or a processor. The terminal processing unit 1602 may transmit and receive signals to and from the base station through the transceiver. Also, the terminal processing unit 1602 may transmit/receive a signal to/from the counterpart terminal in sidelink communication through the transceiver. The signal may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting a received signal. In addition, the transceiver may receive a signal through a wireless channel and output it to the terminal processing unit 1602 , and transmit the signal output from the terminal processing unit 1602 through a wireless channel. The terminal processing unit 1602 may control a series of processes so that the terminal can operate according to the above-described embodiment of the present disclosure.

17 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present disclosure.

As shown in FIG. 17 , the base station of the present disclosure may include a base station receiving unit 1701 , a base station transmitting unit 1705 , and a base station processing unit 1703 . The base station receiving unit 1701 and the base station transmitting unit 1705 may be collectively referred to as a transceiver in an embodiment of the present disclosure. The base station processing unit 1703 provides DRX-related configuration information to the terminal, and when the operation of Mode 1 in which the base station allocates transmission resources in sidelink communication is performed, sidelink resources are scheduled in consideration of the DRX operation of the terminal and may provide scheduled resource allocation information to the terminal. In this case, the UE can expect the base station to allocate Mode1 resources in consideration of DRX. The base station processing unit 1703 may transmit/receive a signal to/from the terminal through the transceiver unit. The signal may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting a received signal. In addition, the transceiver may receive a signal through the wireless channel and output it to the base station processing unit 1703 , and transmit the signal output from the terminal processing unit 1703 through the wireless channel. The base station processing unit 1703 may control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure.

On the other hand, the embodiments of the present disclosure disclosed in the present specification and drawings are merely presented as specific examples to easily explain the technical content of the present disclosure and help the understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is apparent to those of ordinary skill in the art to which other modifications are possible based on the technical spirit of the present disclosure. In addition, each of the above embodiments may be operated in combination with each other as needed. For example, in all embodiments of the present disclosure, parts may be combined with each other to operate a base station and a terminal.

Claims (6)

In a communication method of a terminal in a wireless communication system supporting sidelink communication,
determining a sensing period within a DRX active time when the terminal performs a Discontinuous Reception (DRX) operation;
performing a sensing operation on a sidelink channel in the determined sensing period; and
and selecting or reselecting a sidelink resource based on the sensing operation.
The method of claim 1,
The sensing period is a slot unit, and when at least a part of the sensing period is within the DRX active time, the sensing operation is performed.
The method of claim 1,
When there is no available resource within the resource selection window for the selection or the reselection of the sidelink resource, the sidelink resource using a preset second resource pool in addition to the first resource pool for the sidelink communication A communication method further comprising the step of randomly selecting
In a terminal in a wireless communication system supporting sidelink communication,
transceiver; and
When the terminal performs a discontinuous reception (DRX) operation, a sensing period is determined within a DRX active time, a sensing operation for a sidelink channel is performed in the determined sensing period, and a sidelink resource based on the sensing operation A terminal comprising a processor configured to select or reselect .
5. The method of claim 4,
The sensing period is a slot unit, and when at least a part of the sensing period is within the DRX active time, the sensing operation is performed.
5. The method of claim 4,
When there is no available resource within the resource selection window for the selection or the reselection of the sidelink resource, the processor is configured to use a preset second resource pool in addition to the first resource pool for the sidelink communication. The terminal further configured to randomly select the sidelink resource.

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