Method and apparatus for allocating resources in a V2X system

Abstract

The present disclosure relates to a communication technique and system for converging a 5G communication system with IoT technology to support a higher data transmission rate than that of a 4G system. The present disclosure may be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety related services, etc.) based on 5G communication technology and IoT related technology. A method and apparatus are provided in which a first UE transmits a first SCI (sidelink control information) requesting coordination information between terminals to a second UE. The first UE receives a second SCI providing the coordination information between terminals from the second UE. The first SCI includes a field indicating that the first SCI is used to request coordination information between terminals.

Description

[Technical field]

[0001] The present invention generally relates to a wireless mobile communication system, and more particularly to a method and apparatus for allocating resources in a process in which a vehicle terminal supporting vehicle-to-everything (V2X) communication transmits and receives information with other vehicle terminals and pedestrian mobile terminals using a side link. [Background technology]

[0002] 4G(4 th In order to meet the increasing demand for wireless data traffic since the commercialization of the 5G (5 generation) communication system, thEfforts are being made to develop a 5G (Next Generation) communication system or pre-5G communication system. For this reason, the 5G communication system or pre-5G communication system is called a Beyond 4G Network communication system or a Post LTE (Long Term Evolution) system. In order to achieve high data transmission rates, the 5G communication system is being considered to be implemented in the ultra-high frequency (mmWave) band (e.g., 60 GHz band). In order to mitigate path loss and increase the transmission distance in the ultra-high frequency band, beamforming, massive MIMO (Multiple-Input Multiple-Output), Full Dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large scale antenna technologies are being discussed in the 5G communication system. Furthermore, to improve the system network, technologies being developed for the 5G communication system include advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device-to-device communication, wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Point), and receive interference cancellation.In addition, advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding) and advanced connection technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non orthogonal multiple access), and SCMA (sparse code multiple access) are being developed for the 5G system.

[0003] Meanwhile, the Internet, a human-centered connection network where humans generate and consume information, is evolving into an IoT (Internet of Things) network that exchanges and processes information between distributed components such as things. IoE (Internet of Everything) technology has also emerged, combining IoT technology and big data processing technology through connection to cloud servers. To realize IoT, technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, technologies such as sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) for connecting things are being researched. In the IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated between connected things to create new value in human life. IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services through the convergence and integration of existing IT (information technology) technologies and various industries.

[0004] As a result, various attempts are being made to apply the 5G communication system (5th generation communication system or New Radio (NR)) to IoT networks. For example, technologies such as sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) can be realized by 5G communication technologies using techniques such as beamforming, MIMO, and array antennas. The application of cloud Radio Access Network (Cloud RAN) as the aforementioned big data processing technology can also be seen as an example of convergence between 5G technology and IoT technology.

[0005] As described above, as wireless communication systems develop, various services can be provided, and therefore, methods for smoothly providing these services are required.

[0006] The above information is provided merely for background information to aid in the understanding of the present disclosure. No determination or assertion has been made as to whether any of the above content is applicable as prior art to the present disclosure. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention relates to a wireless communication system, and to a method and apparatus for allocating resources when a vehicle terminal supporting V2X exchanges information with other vehicle terminals and pedestrian mobile terminals using a sidelink, in particular, to a resource selection method when a terminal performs discontinuous reception (hereinafter, referred to as DRX), and to a resource selection method through cooperation between terminals. [Means for solving the problem]

[0008] According to one embodiment of the present disclosure, there is provided a method performed by a first user equipment (UE) in a communication system. The first UE transmits a first sidelink control information (SCI) requesting inter-UE coordination information to a second UE. The first UE receives a second SCI providing the coordination information between the terminals from the second UE. The first SCI includes a field indicating that the first SCI is used to request the coordination information between the terminals.

[0009] According to another embodiment of the present disclosure, there is provided a method performed by a second user equipment (UE) in a communication system, the second UE receiving a first sidelink control information (SCI) requesting inter-UE coordination information from a first UE, the second UE transmitting a second SCI providing the coordination information to the first UE, the first SCI including a field indicating that the first SCI is used to request the coordination information between the terminals.

[0010] According to another embodiment of the present disclosure, a first user equipment (UE) is provided in a communication system. The first UE includes a transceiver and a controller. The controller is configured to transmit a first sidelink control information (SCI) requesting inter-UE coordination information to a second UE and to receive a second SCI providing the coordination information from the second UE. The first SCI includes a field indicating that the first SCI is used to request the coordination information between the terminals.

[0011] According to another embodiment of the present disclosure, a second user equipment (UE) is provided in a communication system. The second UE includes a transceiver and a controller. The controller is configured to receive a first sidelink control information (SCI) requesting inter-UE coordination information from a first UE, and to transmit a second SCI providing the coordination information to the first UE. The first SCI includes a field indicating that the first SCI is used to request the coordination information between the terminals. Effect of the Invention

[0012] The present invention proposes a resource selection method when discontinuous reception (hereinafter, referred to as DRX) is performed between terminals in sidelink communication. Also, the present invention proposes a resource selection method through cooperation between terminals. The proposed method can be effectively used to minimize power consumption of terminals by applying it. Also, the performance of resource allocation can be improved through the proposed method. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating an example of a communication system to which an embodiment of the present disclosure can be applied; [Diagram 2] 1 is a diagram illustrating a V2X communication method performed through a sidelink according to an embodiment. [Diagram 3] 1 is a diagram illustrating a resource pool defined as a set of resources on time and frequency used for sidelink transmission and reception according to an embodiment. [Figure 4] FIG. 1 is a sequence diagram illustrating a method in which a base station allocates transmission resources in a sidelink according to an embodiment. [Diagram 5]FIG. 11 is a sequence diagram showing a method in which a terminal directly allocates sidelink transmission resources through sensing in a sidelink according to an embodiment. [Figure 6] 1 is a diagram showing a mapping structure of a physical channel mapped to one slot in a sidelink according to an embodiment. [Figure 7] 1 is a diagram for defining a sensing window and a resource selection window required for a UE to perform resource (re)selection and re-evaluation for resource allocation in a sidelink when operating in full sensing according to an embodiment. [Figure 8] 1 is a diagram illustrating a method for performing partial sensing for periodic transmission in a sidelink according to an embodiment. [Figure 9] 1 is a diagram illustrating a method for performing partial sensing for aperiodic transmission in a sidelink according to an embodiment. [Figure 10] 1 is a diagram illustrating a method for performing cooperation between terminals according to an embodiment. [Figure 11a] 1 is a diagram showing inactive time (or off-duration) and active time (or on-duration) of DRX determined by parameters set for DRX when discontinuous reception (hereinafter, DRX) is performed on a sidelink according to one embodiment. [Figure 11b] 1 is a diagram showing inactive time (or off-duration) and active time (or on-duration) of DRX determined by parameters set for DRX when discontinuous reception (hereinafter, DRX) is performed on a sidelink according to one embodiment. [Figure 11c]1 is a diagram showing inactive time (or off-duration) and active time (or on-duration) of DRX determined by parameters set for DRX when discontinuous reception (hereinafter, DRX) is performed on a sidelink according to one embodiment. [Figure 11d] 1 is a diagram showing inactive time (or off-duration) and active time (or on-duration) of DRX determined by parameters set for DRX when discontinuous reception (hereinafter, DRX) is performed on a sidelink according to one embodiment. [Figure 12] 1 is a diagram illustrating a terminal operation method for sensing and resource selection when DRX is performed in a sidelink according to an embodiment. [Figure 13] 1 is a diagram showing a resource selection window when a peer UE transmitting sidelink data in a UE performing DRX operates in Mode 2 according to an embodiment. [Figure 14] 1 is a diagram illustrating an example of a resource selection method when a peer terminal transmits sidelink data in a terminal performing DRX according to an embodiment. [Figure 15] 1 is a diagram illustrating a method of transmitting cooperation information of a terminal according to information for cooperation between terminals; [Figure 16] FIG. 2 is a block diagram showing a configuration of a terminal according to an embodiment. [Figure 17] FIG. 2 is a block diagram showing a configuration of a base station according to an embodiment. [Figure 18] 1 is a diagram illustrating a terminal operation depending on whether a transmitting (Tx) terminal performs periodic transmission according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The same or similar components may be given the same or similar reference numerals even if they are shown in different drawings. In order to avoid obscuring the gist of the present invention, detailed descriptions of configurations or procedures known in the art may be omitted.

[0015] In the accompanying drawings, some components are exaggerated, omitted, or illustrated in a schematic manner, and the size of each component does not completely reflect the actual size.

[0016] The present disclosure is not limited to the embodiments disclosed below, but may be embodied in various different forms, and the embodiments are provided solely so that this disclosure will be complete and will fully convey the scope of the present disclosure to those skilled in the art to which the disclosure pertains, and the present disclosure is only defined by the scope of the claims.

[0017] It will be understood that the combination of each block of the process flow chart and the diagrams of the flow chart can be implemented by computer program instructions. These computer program instructions can be loaded onto a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions executed by the processor of the computer or other programmable data processing equipment generate means for performing the functions described in the flow chart blocks. These computer program instructions can also be stored in a computer usable or computer readable memory that can direct the computer or other programmable data processing equipment to implement the functions in a particular manner, such that the instructions stored in the computer usable or computer readable memory can produce an article of manufacture that includes instruction means for performing the functions described in the flow chart blocks. The computer program instructions can also be loaded onto 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, such that the instructions for operating the computer or other programmable data processing equipment to generate a computer-implemented process can provide steps for performing the functions described in the flow chart blocks.

[0018] Also, each block may represent a module, segment, or portion of code that includes one or more executable instructions for performing a specified logical function. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of order. For example, two blocks shown adjacent to each other may in fact be performed substantially simultaneously, or the blocks may sometimes be performed in reverse order depending on the corresponding functions.

[0019] In this embodiment, the term "module" refers to software or hardware components such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and the "module" performs a specific function. However, the term "module" is not limited to software or hardware. The "module" may be configured to reside in an addressable storage medium, and may be configured to execute one or more processors. Thus, by way of example, the "module" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The components and functions provided in the "module" may be combined into a smaller number of components and "modules" or may be further separated into additional components and "modules". In addition, the components and "modules" may be embodied to execute one or more central processing units (CPUs) in a device or a secure multimedia card. Additionally, in the embodiments, a "unit" may include one or more processors.

[0020] In describing the embodiments of the present disclosure in detail, the main target is the radio access network New RAN (NR) and the core network packet core (5G System or 5G Core Network, or NG Core: next generation core) on the 5G mobile communication standard disclosed by 3GPP (registered trademark) (3rd generation partnership project) LTE. However, the main gist of the present disclosure can be applied to other communication systems having similar technical backgrounds with slight modifications within the scope of the present disclosure without significantly departing from the scope of the present disclosure.

[0021] In the 5G system, a network data collection and analysis function (NWDAF), which is a network function that analyzes and provides data collected in the 5G network, can be defined to support network automation. The NWDAF can collect / store / analyze information from the 5G network and provide the results to unspecified network functions (NFs), and the analysis results can be used independently by each NF.

[0022] For convenience of explanation, some of the terms and names defined in the 3GPP (registered trademark) standard (5G, NR, LTE, or a similar system standard) may be used. However, the present disclosure is not limited by the terms and names, and may be similarly applied to systems according to other standards.

[0023] In addition, terms for identifying connection nodes, terms for network entities, terms for messages, terms for interfaces between network entities, terms for various identification information, etc. used in the following description are examples given for the convenience of description, and are not limited to the terms used in this disclosure, but other terms for objects having equivalent technical meanings may be used.

[0024] Efforts are being made to develop an improved 5G communication system (NR, New Radio) to meet the increasing demand for wireless data traffic since the commercialization of the 4G communication system. To achieve high data transmission rates, the 5G communication system is designed to support the mmWave band (such as the 28 GHz frequency band). To mitigate the path loss of propagation in the ultra-high frequency band and increase the propagation distance, analog beamforming, massive MIMO, FD-MIMO (Full Dimensional MIMO), array antenna, analog beam-forming, and large scale antenna technologies are being discussed in the 5G communication system. In addition, unlike LTE, the 5G communication system supports various subcarrier spacings, including 15 kHz, 30 kHz, 60 kHz, and 120 kHz, and the physical control channel uses Polar Coding and the physical data channel uses LDPC (Low Density Parity Check). In addition, not only DFT-S-OFDM but also CP-OFDM is used as a waveform for uplink transmission. LTE supports HARQ (Hybrid ARQ) retransmission on a TB (Transport Block) basis, but 5G can additionally support HARQ retransmission based on CBG (Code Block Group) including CB (Code Block) bundles.

[0025] In addition, to improve the system network, technologies being developed for the 5G communication system include advanced small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device to device communication (D2D), wireless backhaul, vehicle to everything (V2X) networks, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation.

[0026] In this way, a communication system can provide a plurality of services to a user, and a method and an apparatus using the same are required to provide each service within the same time period so as to meet the characteristics of providing the plurality of services to the user. Various services to be provided in a 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, the NR V2X system supports unicast communication, groupcast (or multicast) communication, and broadcast communication between terminals. In addition, unlike LTE V2X, which aims to transmit and receive basic safety information required for vehicles to travel on roads, NR V2X aims to provide more advanced services such as platooning, advanced driving, extended sensor, and remote driving.

[0027] Inter-UE coordination can be considered in the sidelink. Here, inter-UE coordination means providing improved sidelink services by sharing useful information between the terminals. In the present invention, information shared for inter-UE cooperation is not limited to specific information. For example, such information may include resource selection assistance information (hereinafter, referred to as RSAI). The present invention provides various methods for a terminal to request or provide inter-UE cooperation information.

[0028] In particular, discontinuous reception (hereinafter, DRX) between terminals can be considered in sidelink communication. When DRX is applied, it is possible to minimize the power consumption of the terminal and improve battery efficiency. Specifically, the power consumed by the terminal can be generated in the following process.

[0029] *Control information transmitted through PSCCH (physical sidelink control channel)1 st SCI Decoding: 1st SCI contains terminal scheduling information. st This information can be used to decode SCI and perform sensing.

[0030] *Control information transmitted via PSSCH (physical sidelink shared channel) 2 nd SCI Decoding:2 nd 1 for SCI st It contains other control information not included in the SCI.

[0031] * Decoding of data transmitted over PSSCH

[0032] Therefore, when DRX is applied in the sidelink, the terminal may not decode the control information and data information in a time period set as the inactive time. In contrast, when DRX is applied in the sidelink, the terminal may decode the control information and data information only in a time period set as the active time. Therefore, successful data reception of the receiving terminal can be guaranteed only when the transmitting terminal transmits data in a period set as the DRX active time of the receiving terminal in the sidelink. In other words, when the transmitting terminal transmits data in a period set as the DRX inactive time of the receiving terminal in the sidelink, the receiving terminal may not be able to receive the corresponding signal. In consideration of this point, the present invention proposes a method for the transmitting terminal to select resources.

[0033] The embodiments are proposed to support the above mentioned scenarios and aim to provide a method and apparatus for multiple antenna transmission, especially in the sidelink.

[0034] FIG. 1 is a diagram illustrating an example of a communication system to which an embodiment of the present disclosure can be applied.

[0035] Referring to FIG. 1, an example is shown in (a) for the case where all V2X terminals (UE-1 and UE-2) are located within the coverage of the base station (In-Coverage, IC). All V2X terminals can receive data and control information from the base station via a downlink (DL) or transmit data and control information to the base station via an uplink (UL). In this case, the data and control information may be data and control information for V2X communication. The data and control information may be data and control information for general cellular communication. In addition, the V2X terminals can transmit / receive data and control information for V2X communication via a sidelink (SL).

[0036] Further, referring to FIG. 1, an example of a case where UE-1 of the V2X terminals is located within the coverage of a base station and UE-2 is located outside the coverage of the base station is illustrated in (b). That is, (b) illustrates an example of partial coverage (PC) where a part of the V2X terminal (UE-2) is located outside the coverage of the base station. The V2X terminal (UE-1) located within the coverage of the base station can receive data and control information from the base station through a downlink or transmit data and control information to the base station through an uplink. The V2X terminal (UE-2) located outside the coverage of the base station cannot receive data and control information from the base station through a downlink, and cannot transmit data and control information to the base station through an uplink. The V2X terminal (UE-2) can transmit / receive data and control information for V2X communication with the V2X terminal (UE-1) through a sidelink.

[0037] 1, an example of a case where all V2X terminals are located out-of-coverage (OOC) of the base station is shown in (c). Therefore, the V2X terminals (UE-1, UE-2) cannot receive data and control information from the base station through a downlink, and cannot transmit data and control information to the base station through an uplink. The V2X terminals (UE-1, UE-2) can transmit / receive data and control information for V2X communication through a sidelink.

[0038] Referring to FIG. 1, an example of a scenario in which V2X communication is performed between V2X terminals (UE-1, UE-2) located in different cells is illustrated in (d). Specifically, (d) illustrates a case in which the V2X terminals (UE-1, UE-2) are connected to different base stations (RRC connected state) or camping (RRC disconnected state or RRC idle state). In this case, 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 a base station to which it is connected (or camped), and the V2X terminal (UE-2) may receive a SIB from another base station to which it is connected (or camped). In this case, the SIB may be an existing SIB or a SIB defined separately for V2X. Also, the SIB information received by the V2X terminal (UE-1) may differ from the SIB information received by the V2X terminal (UE-2). Therefore, in order to perform V2X communication between terminals (UE-1, UE-2) located in different cells, the information may be unified or the information may be signaled, and an additional method for analyzing the SIB information transmitted from each different cell may be required.

[0039] In FIG. 1, a V2X system composed of V2X terminals (UE-1, UE-2) is illustrated for convenience of explanation, but communication may be performed between more V2X terminals. In addition, an interface (uplink and downlink) between a base station and a V2X terminal may be referred to as a Uu interface, and a sidelink between V2X terminals may be referred to as a PC5 interface. Therefore, these may be used in combination in the present disclosure. Meanwhile, in the present disclosure, the terminal may include a vehicle supporting communication between vehicles (vehicular-to-vehicular, V2V), a vehicle or pedestrian headset (e.g., a smartphone) supporting communication between vehicles and pedestrians (vehicular-to-pedestrian, V2P), a vehicle supporting communication between vehicles and a network (vehicular-to-network, V2N), or a vehicle supporting communication between vehicles and a transportation infrastructure (vehicular-to-infrastructure, V2I). In addition, in the present disclosure, a terminal may include an RSU (road side unit) equipped with terminal functions, an RSU equipped with base station functions, or an RSU equipped with part of the base station functions and part of the terminal functions.

[0040] According to an embodiment of the present disclosure, the base station may be a base station that supports both V2X communication and general cellular communication, or a base station that supports only V2X communication. In this case, the base station may be a 5G base station (gNB), a 4G base station (eNB), or an RSU. Therefore, in the present disclosure, the base station may be referred to as an RSU.

[0041] FIG. 2 is a diagram illustrating a V2X communication method performed through a sidelink according to an embodiment.

[0042] Referring to FIG. 2(a), UE-1 (201, for example, a TX terminal) and UE-2 (202, for example, an RX terminal) can communicate one-to-one, which can be called unicast communication.

[0043] Referring to FIG. 2(b), a TX terminal and an RX terminal can communicate one-to-many, which can be called groupcast or multicast. In FIG. 2(b), UE-1 (211), UE-2 (212), and UE-3 (213) form one group (Group A) and perform groupcast communication, and UE-4 (214), UE-5 (215), UE-6 (216), and UE-7 (217) form another group (Group B) and perform groupcast communication. Each terminal performs groupcast communication only within the group to which it belongs, and communication between groups can be performed through unicast, groupcast, or broadcast communication. In FIG. 2(b), two groups (Group A and Group B) are shown to be formed, but the present invention is not limited thereto.

[0044] Meanwhile, although not shown in FIG 2, the V2X terminal can perform broadcast communication. Broadcast communication refers to the case where all V2X terminals receive data and control information transmitted by a V2X transmitting terminal through a sidelink. In one example, assuming that UE-1 (211) is a transmitting terminal for broadcast in FIG 2(b), all terminals (UE-2 (212), UE-3 (213), UE-4 (214), UE-5 (215), UE-6 (216), and UE-7 (217)) can receive data and control information transmitted by UE-1 (211).

[0045] Unlike LTE V2X, NR V2X can support a form in which a vehicle terminal transmits data only to one specific node through unicast and a form in which a vehicle terminal transmits data to a number of specific nodes through groupcast. For example, such unicast and groupcast technologies can be usefully used in a service scenario such as platooning, a technology in which two or more vehicles are connected to one network and move in a cluster. Specifically, unicast communication may be required for the leader node of a group connected by platooning to control one specific node, and groupcast communication is required for the purpose of simultaneously controlling a group consisting of a number of specific nodes.

[0046] FIG. 3 is a diagram illustrating a resource pool defined as a set of resources on time and frequency used for sidelink transmission and reception according to one embodiment.

[0047] The resource allocation unit on the resource pool time axis may be a slot. Also, the resource allocation unit on the frequency axis may be a sub-channel consisting of one or more physical resource blocks (PRBs). In this disclosure, an example in which the resource pool is allocated discontinuously on the time axis is described, but the resource pool may be allocated contiguously on the time axis. Also, in this disclosure, an example in which the resource pool is allocated contiguously on the frequency axis is described, but a method in which the resource pool is allocated discontinuously on the frequency axis is not excluded.

[0048] Referring to FIG. 3, a case where a resource pool is allocated discontinuously in time (301) is illustrated. A case where the granularity of resource allocation in time is a slot is illustrated. First, a sidelink slot can be defined among slots used in the uplink. Specifically, the length of symbols used in the sidelink in one slot can be set as sidelink BWP (Bandwidth Part) information. Therefore, among slots used in the uplink, a slot in which the length of symbols set as the sidelink is not guaranteed cannot become a sidelink slot. In addition, slots belonging to the resource pool exclude slots in which S-SSB (Sidelink Synchronization Signal Block) is transmitted. Referring to 301, a set of slots that can be used in the sidelink in time excluding such slots is defined as

number

number

[0049] Referring to 303 in FIG. 3, a case where a resource pool is allocated contiguously on the frequency axis is illustrated. The resource allocation on the frequency axis may be set as sidelink BWP (Bandwidth Part) information and may be in sub-channel units. The sub-channel may be defined as a resource allocation unit on the frequency axis composed of one or more PRBs (Physical Resource Blocks). That is, the sub-channel may be defined as an integer multiple of the PRB. Referring to 303, the sub-channel may be composed of five consecutive PRBs, and the sub-channel size (sizeSubchannel) may be the size of five consecutive PRBs. However, the content illustrated in FIG. 3 is only an example, and the size of the sub-channel may be set to be different, and one sub-channel is generally composed of consecutive PRBs, but does not necessarily have to be composed of consecutive PRBs. The sub-channel may be a basic unit of resource allocation for the PSSCH. In 303, startRB-Subchannel may indicate the start position of the sub-channel on the frequency axis in the resource pool. When resource allocation on the frequency axis is in subchannel units, resources on the frequency axis can be allocated through configuration information on the RB (Resource Block) index (startRB-Subchannel) where the subchannel starts, information on how many PRBs the subchannel is composed of (sizeSubchannel), and the total number of subchannels (numSubchannel), etc. At this time, information on startRB-Subchannel, sizeSubchannel, and numSubchannel, etc. can be (pre-)configured in the frequency resource pool information.

[0050] FIG. 4 is a sequence diagram illustrating a method for allocating transmission resources in a sidelink by a base station according to one embodiment.

[0051] A method in which the base station allocates transmission resources in the sidelink is hereinafter referred to as Mode 1. Mode 1 may be scheduled resource allocation. Mode 1 may refer to a method in which the base station allocates resources used for sidelink transmission to an RRC-connected terminal in a dedicated scheduling manner. The method of Mode 1 is effective in interference management and resource pool management since the base station can manage sidelink resources.

[0052] 4, a transmitting terminal 401 (Tx UE) can camp on (405) a base station (cell or gNB) 403. The camp on can refer to a state in which a terminal in an idle state (RRC_IDLE) can select (or reselect) a base station (cell) as necessary to receive system information or paging information.

[0053] On the other hand, if the receiving terminal 402 (Rx UE) is located within the coverage of the base station (cell) 403, the receiving terminal 402 can camp on the base station 403 (407). In contrast, if the receiving terminal 402 is located outside the coverage of the base station 403, the receiving terminal 402 may not camp on the base station 403.

[0054] In this disclosure, the receiving terminal 402 refers to a terminal that receives data transmitted by the transmitting terminal 401 .

[0055] The transmitting terminal 401 and the receiving terminal 402 can receive a sidelink system information block (SL-SIB) from the base station 403 (410). The SL-SIB information may include sidelink resource pool information for sidelink transmission / reception, parameter setting information for sensing operation, information for setting sidelink synchronization, or carrier information for sidelink transmission / reception operating at different frequencies.

[0056] When data traffic for V2X is generated in the transmitting terminal 401, the transmitting terminal 401 can be RRC connected with the base station 403 (420). Here, the RRC connection between the terminal and the base station can be referred to as Uu-RRC. The Uu-RRC connection procedure 420 can be performed before the data traffic is generated in the transmitting terminal 401. Also, in Mode 1, the transmitting terminal can transmit to the receiving terminal through a side link in a state where the Uu-RRC connection procedure 420 between the base station 403 and the receiving terminal 402 is performed. In contrast, in Mode 1, the transmitting terminal can transmit to the receiving terminal through a side link even in a state where the Uu-RRC connection procedure 420 between the base station 403 and the receiving terminal 402 is not performed.

[0057] The transmitting terminal 401 may request a transmission resource for V2X communication with the receiving terminal 402 from the base station (430). At this time, the transmitting terminal 401 may request the sidelink transmission resource from the base station 403 using an uplink physical control channel (PUCCH), an RRC message, or a medium access control (MAC) control element (CE). Meanwhile, the MAC CE may be a buffer status report (BSR) MAC CE in a new format (including at least an indicator notifying that it is a buffer status report for V2X communication and information on the size of data buffered for D2D communication). Also, the transmitting terminal 401 may request the sidelink resource through a scheduling request (SR) bit transmitted through the uplink physical control channel.

[0058] Next, the base station 403 can allocate V2X transmission resources to the transmitting terminal 401. At this time, the base station can allocate the transmission resources in a dynamic grant or configured grant manner.

[0059] First, in the case of the dynamic grant method, the base station can allocate resources for TB transmission through downlink control information (DCI). The sidelink scheduling information included in the DCI can include parameters related to the transmission time of the initial transmission and retransmission and the frequency allocation location information field. The DCI for the dynamic grant method can be CRC scrambled with the SL-V-RNTI to indicate the dynamic grant method.

[0060] Next, in the case of the configured grant method, the base station can periodically allocate resources for TB transmission by setting a semi-persistent scheduling (SPS) interval through Uu-RRC. At this time, the base station can allocate resources for one TB through DCI. Sidelink scheduling information for one TB included in DCI can include parameters related to transmission time and frequency allocation location information of initial transmission and retransmission resources. When resources are allocated in the configured grant method, the transmission time (occasion) and frequency allocation location of initial transmission and retransmission for one TB can be determined by the DCI, and resources for the next TB can be repeated at SPS interval intervals. DCI for the configured grant method can be CRC scrambled with SL-SPS-V-RNTI to indicate that it is the configured grant method. Also, the configured grant (CG) method can be divided into Type 1 CG and Type 2 CG. In the case of Type 2 CG, resources set as configured grant through DCI can be activated / deactivated.

[0061] Therefore, in the case of Mode 1, the base station 403 can instruct the transmitting terminal 401 to perform scheduling for sidelink communication with the receiving terminal 402 by transmitting DCI through a physical downlink control channel (PDCCH) (440).

[0062] Specifically, the base station 403 may use DCI (Downlink Control Information) for sidelink communication with the transmitting terminal 401 in DCI format 3_0 or DCI format 3_1. DCI format 3_0 may be defined as DCI for scheduling an NR sidelink in one cell, and DCI format 3_1 may be defined as DCI for scheduling an LTE sidelink in one cell.

[0063] In the case of broadcast transmission, the transmitting terminal 401 can perform transmission without RRC setting 415 for sidelink. In contrast, in the case of unicast or groupcast transmission, the transmitting terminal 401 can also perform one-to-one RRC connection with other terminals. Here, the RRC connection between terminals can be referred to as PC5-RRC 415 in distinction from Uu-RRC. In the case of groupcast, PC5-RRC 415 can be individually connected between terminals in a group. Referring to FIG. 4, the PC5-RRC 415 connection is illustrated as an operation after SL-SIB transmission 410, but it can also be performed at any time before SL-SIB transmission 410 or SCI transmission.

[0064] Next, the transmitting terminal 401 transmits an SCI(1) to the receiving terminal 402 via a PSCCH (physical sidelink control channel). st In addition, the transmitting terminal 401 can transmit an SCI (2 stage) to the receiving terminal 402 via the PSSCH (460). nd At this time, 1 st The information on resource allocation is stored in the stage SCI. ndOther control information can be included in the stage SCI. Also, the transmitting terminal 401 can transmit data to the receiving terminal 402 through the PSSCH (480). At this time, the SCI ( st stage), SCI(2 nd stage), and PSSCH can be transmitted together in the same slot.

[0065] FIG. 5 is a sequence diagram illustrating a method in which a terminal directly allocates sidelink transmission resources through sensing in a sidelink according to an embodiment.

[0066] Hereinafter, a method in which a terminal directly allocates sidelink transmission resources through sensing in the sidelink is referred to as Mode 2. Mode 2 can also be referred to as UE autonomous resource selection. In Mode 2, the base station (gNB) 503 provides a sidelink transmission / reception resource pool for V2X in system information, and the transmitting terminal (Tx UE) 501 can select transmission resources according to the determined rule. Unlike Mode 1 in which the base station is directly involved in resource allocation, in FIG. 5, the transmitting terminal 501 autonomously selects resources based on a resource pool previously received through system information and transmits data.

[0067] Referring to FIG. 5, a transmitting terminal 501 can camp on a base station 503 (505). The camp on can mean, for example, a state in which a terminal in an idle state (RRC_IDLE) can select (or reselect) a base station (cell) as necessary and receive system information or paging information. Also, referring to FIG. 5, unlike FIG. 4, in the case of Mode 2, if the transmitting terminal 501 is located within the coverage of the base station (cell) 503, the transmitting terminal 501 can camp on the base station 503 (507). In contrast, if the transmitting terminal 501 is located outside the coverage of the base station 503, the transmitting terminal 501 may not camp on the base station 503.

[0068] On the other hand, if a receiving terminal (Rx UE) 502 is located within the coverage of a base station (cell) 503, the receiving terminal 502 can camp on the base station 503 (507). In contrast, if the receiving terminal 502 is located outside the coverage of the base station 503, the receiving terminal 502 may not camp on the base station 503.

[0069] In this disclosure, a receiving terminal 502 refers to a terminal that receives data transmitted by a transmitting terminal 501 .

[0070] The transmitting terminal 501 and the receiving terminal 502 can receive a sidelink system information block (SL-SIB) from the base station 503 (510). The SL-SIB information can include sidelink resource pool information for sidelink transmission / reception, parameter setting information for sensing operation, information for setting sidelink synchronization, or carrier information for sidelink transmission / reception operating at different frequencies.

[0071] The difference between FIG. 4 and FIG. 5 is that in FIG. 4, the base station 503 and the terminal 501 operate in an RRC connected state, whereas in FIG. 5, the terminal can operate in an idle mode 520 (not RRC connected state). Also, even in the RRC connected state 520, the base station 503 does not directly participate in resource allocation, and the transmitting terminal 501 can autonomously select a transmission resource. Here, the RRC connection between the terminal 501 and the base station 503 may be referred to as Uu-RRC 520. When data traffic for V2X is generated in the transmitting terminal 501, a resource pool is set in the transmitting terminal 501 through system information received from the base station 503, and the transmitting terminal 501 can directly select a time / frequency domain resource through sensing within the set resource pool (530). When the resource is finally selected, the selected resource is determined by a grant for sidelink transmission.

[0072] In the case of broadcast transmission, the transmitting terminal 501 can perform transmission without RRC setting 515 for sidelink. In contrast, in the case of unicast or groupcast transmission, the transmitting terminal 501 can also perform one-to-one RRC connection with other terminals. Here, the RRC connection between terminals may be referred to as PC5-RRC 515 in distinction from Uu-RRC. In the case of groupcast, PC5-RRC 515 can be individually connected between terminals in a group. Referring to FIG. 5, the connection of PC5-RRC 515 is illustrated as an operation after transmission 510 of SL-SIB, but it can also be performed at any time before transmission 510 of SL-SIB or before transmission of SCI.

[0073] Next, the transmitting terminal 501 transmits SCI(1) to the receiving terminal 502 via the PSCCH. st In addition, the transmitting terminal 401 can transmit an SCI (2 stage) to the receiving terminal 402 via the PSSCH (550). nd At this time, 1 st The information on resource allocation is stored in the stage SCI. nd Other control information can be included in the stage SCI. Also, the transmitting terminal 501 can transmit data to the receiving terminal 502 through the PSSCH (570). At this time, the SCI (1 st stage), SCI(2 nd stage), and PSSCH can be transmitted together in the same slot.

[0074] Specifically, the SCI (Downlink Control Information) used by the transmitting terminals 401 and 501 for sidelink communication with the receiving terminals 402 and 502 is SCI(1 st stage) and SCI format1-A are sufficient. Also, SCI(2 nd stage) with SCI format2-A or SCI format2-B. ndIn the second stage, SCI format 2-A can be used by including 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 can be used by including information for PSSCH decoding when HARQ feedback is not used or when HARQ feedback is used and includes only NACK information. For example, SCI format 2-B can be used limited to groupcast transmission.

[0075] FIG. 6 is a diagram illustrating a mapping structure of physical channels mapped to one slot in a sidelink according to an embodiment.

[0076] Specifically, FIG. 6 illustrates mapping for PSCCH / PSSCH / PSFCH physical channels. In the case of PSFCH, if sidelink HARQ feedback is activated in the upper layer, the time resource of PSFCH can be pre-configured with resource pool information. Here, the time resource in which PSFCH is transmitted can be pre-configured with one value of 0, 1, 2, or 4 slots. Here, '0' means that the PSFCH resource is not used. And 1, 2, or 4 can mean that the PSFCH resource is transmitted every 1, 2, or 4 slots, respectively. FIG. 6(a) illustrates a slot structure in which the PSFCH resource is not configured, and FIG. 6(b) illustrates a slot structure in which the PSFCH resource is configured. PSCCH / PSSCH / PSFCH can be assigned to one or more subchannels in frequency. For details on subchannel assignment, refer to the description of FIG. 3. Next, referring to FIG. 6 to explain the mapping of PSCCH / PSSCH / PSFCH on time, one or more symbols before the transmitting terminal transmits PSCCH / PSSCH / PSFCH (physical sidelink feedback channel) in a slot 601 can be used in an area 602 for automatic gain control (AGC). When the symbol is used for AGC, a method of repeatedly transmitting a signal of another channel in the symbol area can be considered. In this case, the repeated signal of another channel can be considered as a PSCCH symbol or a part of a PSSCH symbol. Alternatively, a preamble can be transmitted in the AGC area. When a preamble signal is transmitted, there is an advantage that the AGC execution time can be shortened more than the method of repeatedly transmitting a signal of another channel.When a preamble signal is transmitted for AGC, a specific sequence may be used as the preamble signal 602, and the preamble may use sequences such as PSSCH DMRS (demodulation reference signal), PSCCH DMRS, and CSI-RS (channel state information reference signal). In this disclosure, the sequence used in the preamble is not limited to the above example. Additionally, according to FIG. 6, the first symbol of the slot contains control information related to resource allocation. st The other control information is transmitted to PSCCH603 in stage SCI (sidelink control information). nd In the stage SCI, data scheduled by the control information can be transmitted in the PSSCH area 604. Data scheduled by the control information can be transmitted in the PSSCH 605. nd The time position where the stage SCI is transmitted can be mapped from the symbol where the first PSSCH DMRS 606 is transmitted. The time position where the PSSCH DMRS 606 is transmitted can be changed between a slot where the PSFCH is transmitted and a slot where the PSFCH is not transmitted, as shown in Figures 6(a) and 6(b). Figure 6(a) illustrates that the PSFCH 607 (physical sidelink feedback channel), which is a physical channel for transmitting feedback information, is located at the end of the slot. A certain amount of free time (Guard) can be secured between the PSSCH 605 and the PSFCH 607 so that the terminal that has transmitted or received the PSSCH 605 can prepare to transmit or receive the PSFCH 607. In addition, a certain amount of free time (Guard) can be secured after the transmission or reception of the PSFCH 607.

[0077] FIG. 7 is a diagram for defining a sensing window and a resource selection window required for a terminal to perform resource (re)selection and re-evaluation for resource allocation in a sidelink when operating in full sensing according to one embodiment.

[0078] When triggering for resource (re)selection occurs at time n, the sensing window 701 is [nT 0 ,nT proc,0 ], where T 0 is the start of the sensing window and can be pre-configured with resource pool information. 0 can be defined as a positive integer in ms. 0 We do not limit T to a specific value. proc,0 can be defined as the time required to process the sensing result. proc,0 The value set to T is not limited to a specific value. For example, proc,0 can be defined as a positive integer in units of ms or slots.

[0079] Next, when triggering for resource (re)selection occurs at time n, the resource selection window 702 is [n+T 1 ,n+T 2 ], where T 1 is the value in slot units, and T 1 ≦T proc,1 can be selected for terminal implementation. proc,1 can be defined as a maximum criterion value that takes into account the processing time required to select a resource. For example, T proc,1 can be defined to different values ​​according to SCS (Subcarrier Spacing) in slot units. proc,1 The value set to T is not limited to a specific value. 2is the slot unit value. 2min ≦T 2 ≤ Remaining Packet Delay Budget (PDB). 2min is the value of T that is too small for the device 2 This is to prevent the selection of T 2min The value is determined according to the priority (prioTX) and SCS of the transmitting terminal. 2min (prio TX )' can be set in the upper layer. The terminal can select a transmission resource within the resource selection window 702.

[0080] FIG. 7 illustrates an example in which re-evaluation and pre-emption are triggered at n' (n'>n) by continuously sensing even after resource (re-)selection is triggered at time n. Specifically, if it is determined that the selected resource is not suitable for transmission after continuously sensing is performed after resource (re-)selection is triggered at time n, re-evaluation may be triggered at time n' (n'>n). In addition, when the resource reserved by the terminal overlaps with the resource reserved by another terminal, pre-emption may be triggered at time n' (n'>n) if the priority of the resource reserved by the other terminal is high and interference with the resource is measured high. In this case, the resource selected and reserved by resource (re-)selection at time n (703) may be changed to another resource (706). FIG. 7 shows a sensing window 704 and a resource selection window 705 for a time point n' (n'>n) that triggers re-evaluation and pre-emption.

[0081] 8 to 9 illustrate a method of performing partial sensing in a sidelink according to an embodiment of the present disclosure. Unlike full sensing in FIG. 7, FIG. 8 to 9 illustrate different methods of determining a slot for performing sensing when a UE operates in partial sensing. However, it should be noted that the present invention is not limited to the methods presented in FIG. 8 to 9. It should be noted that when partial sensing is performed in FIG. 8 to 9, the resource selection window (801 to 901) can be determined as described through 702 in FIG. 7.

[0082] First, referring to FIG. 8, one method of performing partial sensing has been presented. The method presented through FIG. 8 may correspond to a partial sensing method performed when performing periodic resource reservation. In other words, it is a partial sensing method for periodic transmission. However, it should be noted that the method presented through FIG. 8 may be referred to by other terms. Referring to FIG. 8, Y (≧1) candidate slots may be selected in a resource selection window (801, RSW). At this time, the Y candidate slots may be selected contiguously or non-contiguously in time in the resource selection window. The minimum value of Y may be (pre-)configured. The final selection of the value of Y and which slot is selected may be determined by the terminal implementation. At this time, one of the Y candidate slots is selected as shown in 802.

number

number

number

[0083] *Method 1: All values ​​in sl-ResoureReservePeriodList are used

[0084] *Method 2: Only a subset of the values ​​in sl-ResoureReservePeriodList is used

[0085] *Method 3: The common divisor of the values ​​in sl-ResoureReservePeriodList is used.

[0086] moreover,

number

number

[0087] Referring to FIG. 9, another method for performing partial sensing is presented. The method presented in FIG. 9 is a partial sensing method for aperiodic transmission, which is not the partial sensing for periodic transmission of FIG. 8, and can be applied when periodic resource reservation is not performed. Unlike FIG. 8, Y' (≧1) candidate slots can be selected in a resource selection window (901, RSW). At this time, the Y' candidate slots may be selected contiguously or non-contiguously in time in the resource selection window. The minimum value of Y' can be (pre-)configured. The final selection of the value of Y' and which slot is selected can be determined by the terminal implementation. At this time, one of the Y' candidate slots is selected as shown in 902.

number

number

number

number

[0088] FIG. 10 is a diagram illustrating two methods of cooperation between terminals according to an embodiment.

[0089] According to the cooperation method 1 between terminals (1001), the UE-A may provide the UE-B with set information 1003 of time-frequency resource allocation suitable (preferable) or unsuitable (unpreferable) for transmission. In contrast, according to the cooperation method 2 between terminals (1002), the UE-A may provide the UE-B with only the suitability of resources reserved by the UE-B in the SCI. In the case of the cooperation method 1 between terminals, since the UE-A must signal the set information 1003 of time-frequency resource allocation to the UE-B, the signaling overhead may be increased compared to the cooperation method 2 between terminals. In the case of the cooperation method 2 between terminals, since the UE-A signals to the UE-B only the suitability of resources reserved by the UE-B in the SCI, the suitability may be indicated by, for example, 1-bit information.

[0090] FIG. 11 is a diagram showing inactive time (or off-duration) and active time (or on-duration) of discontinuous reception (hereinafter, DRX) determined by parameters set for DRX when DRX is performed in the sidelink according to an embodiment. The UE may decode control information and data information for data reception in a period corresponding to the active time of DRX. Alternatively, the UE may not decode control information and data information for data reception in a period corresponding to the inactive time of DRX. In the sidelink, the control information transmitted through the PSCCH is 1 st 2 is control information transmitted via SCI and PSSCH nd There is an SCI. In addition, data information can be transmitted through the PSSCH. It can be assumed that control information and data information are always transmitted simultaneously in the sidelink. Therefore, the time (slot) at which control information is received may be the same as the time (slot) at which data information is received.

[0091] The following parameters may be considered for determining the inactive time and active time for sidelink DRX. However, the parameters for determining the inactive time and active time for DRX are not limited to the parameters presented below. Also, please note that some of the following parameters may not be used in sidelink DRX.

[0092] DRX related parameters

[0093] *drx-cycle: indicates a cycle in which DRX is applied, and the start position (drx-StartOffset) of the drx-cycle 1101 can be set. As shown in Figs. 11a-11d, an inactive time 1110 and an active time (1111) section can be set within the drx-cycle. A drx-cycle having a long cycle and a short cycle can be set in the sidelink.

[0094] *drx-onDurationTimer: A time during which the DRX active time (or on-duration) operates in the drx-cycle 1101, and may correspond to the DRX active time 1110 until the drx-onDurationTimer 1102 expires. The remaining period of the drx-cycle 1101 from the time the drx-onDurationTimer 1102 expires may become the DRX inactive time 1111. An example of a case in which only the drx-onDurationTimer 1102 is defined in the sidelink and the DRX inactive time 1110 and active time 1111 are manipulated is shown in FIG. 11(a).

[0095] *drx-InactivityTimer: If sidelink control information is received (1103) before the drx-onDurationTimer 1102 expires within the drx-cycle 1101, the drx-InactivityTimer 1104 operates from the time the control information is received until it expires, and the DRX active time can be extended (1110). The remaining period of the drx-cycle 1101 from the time the drx-InactivityTimer 1104 expires can be the DRX inactive time 1111. An example of a case where the drx-onDurationTimer 1102 and the drx-InactivityTimer 1104 are defined in the sidelink and the DRX inactive time (1110) and active time 1111 are operated is shown in FIG. 11(b).

[0096] *drx-HARQ-RTT-Timer: When retransmission is performed on the sidelink, the terminal can trigger the drx-HARQ-RTT-Timer (1105) within the DRX active time 1111 (1103). The conditions for triggering the drx-HARQ-RTT-Timer 1105 on the sidelink are to receive sidelink control information or to receive sidelink control information and then transmit sidelink control information (1 st When location information for retransmission is indicated in the 1st SCI, the drx-HARQ-RTT-Timer 1105 can be applied until the next retransmission is received according to the information. When the drx-HARQ-RTT-Timer 1105 expires, the terminal can operate in the DRX active time 1111 to receive the retransmission. In this case, the DRX active time 1111 can be the period during which the drx-RetransmissionTimer 1106 operates. As described above, since location information of the initial transmission and retransmission resources (including information on the presence or absence of retransmission resources) is indicated in the 1st SCI, the drx-HARQ-RTT-Timer 1105 is applied until the next retransmission is received according to the information. st It can also be assumed and defined as the time gap between the initial transmission and the retransmission resources indicated in the SCI or the time gap between the retransmission resources. st If the SCI indicates that there are no retransmission resources, the drx-HARQ-RTT-Timer 1105 may not operate. An example in which the drx-onDurationTimer 1102, the drx-InactivityTimer 1104, the drx-HARQ-RTT-Timer 1105, and the drx-RetransmissionTimer 1106 are defined in the sidelink and the DRX inactive time 1110 and active time 1111 are operated is shown in FIG. 11(c).

[0097] *drx-RetransmissionTimer:** When retransmission is performed in the sidelink, the drx-RetransmissionTimer 1106 can operate from the time when the drx-HARQ-RTT-Timer 1105 expires. Therefore, the drx-RetransmissionTimer does not operate during the time period when the drx-HARQ-RTT-Timer 1105 operates. Also, the drx-RetransmissionTimer 1106 in the sidelink can 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 invention is not limited thereto. That is, the drx-RetransmissionTimer in the sidelink can be set to a value of one or more slots or one or more subframes. Therefore, as shown in FIG. 11(c), the operating period of the drx-RetransmissionTimer 1106 is set to the active time 1112 of DRX, and the retransmission of the peer terminal can be received. Also, the remaining drx-cycle period may be set as DRX inactive time 1113, so that the terminal does not receive control and data information.

[0098] * drx-SlotOffset: Can be used to adjust the start position where sidelink DRX is applied when various SCSs (Subcarrier Spacings) are supported.

[0099] *WUS (wake-up signal) cycle: When WUS is used in the sidelink, a WUS cycle can be set. Assuming that WUS is transmitted by the WUS cycle, the UE can perform monitoring for WUS at the position where WUS is transmitted (1107). Referring to FIG. 11(d), an example is shown in which the WUS (wake-up signal) is used to determine the inactive time and active time of DRX. If the WUS instructs the UE not to wake up in 1107 as in FIG. 11(d), the UE does not operate the drx-onDurationTimer 1102 in the drx-cycle 1101, and all drx-cycle intervals can be set to the inactive time of DRX (1110). On the other hand, if the WUS instructs the UE to wake up in 1107, the UE can perform the operation as shown in FIG. 11(a), FIG. 11(b), or FIG. 11(c) according to the set DRX parameters.

[0100] According to the above description, the active time (or on-duration) in DRX can be defined by when a DRX cycle is configured in the sidelink and when the active time (or on-duration) and / or drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimer operates.

[0101] As described above, some of the parameters may not be used in sidelink DRX. Or other parameters may be considered. This may vary depending on the transmission method of sidelink broadcast, unicast, or groupcast. In addition, the method of setting the parameter information is not limited to a specific method. The information may be (pre-)configured, or in the case of unicast, it may be set through PC5-RRC or sidelink MAC-CE.

[0102] In the following embodiments, a method for sensing and selecting resources in Mode 2 by a terminal when DRX is operated in the sidelink (FIGS. 11a-11d) is provided. A method for cooperation between terminals in the sidelink is also proposed.

[0103] In the first embodiment, a terminal operation method for sensing and resource selection when DRX is performed in a sidelink is provided.

[0104] Specifically, FIG. 12 illustrates four terminals performing transmission and reception in the sidelink according to an embodiment of the present disclosure. In FIG. 12, UE1 is a terminal that is going to perform sidelink data transmission, i.e., PSSCH transmission, in UE2, and UE2 may be a terminal performing sidelink DRX. As described above, if UE1 transmits sidelink data in the period in which UE2 operates in DRX inactive time in the sidelink (in other words, UE2 may not perform decoding of control information and data information in the corresponding time period), UE2 may not be able to receive the sidelink data. Therefore, as shown in 1201, a peer terminal that transmits sidelink data in the terminal performing DRX needs to perform resource selection so that a receiving terminal can receive the transmission data when selecting resources by performing Mode 2 sensing. For a detailed method of this, please refer to the following second and third embodiments. Then, UE1 can select the resource determined through the resource selection operation considered in 1201 and transmit PSCCH / PSSCH 1202 in UE2. Next, in FIG. 12, UE2 is a terminal performing sidelink DRX, and the sensing operation in the inactive time and active time of sidelink DRX may be the same or different. For the detailed method in the same case, refer to FIG. 7 to FIG. 10. Alternatively, sensing may be performed in a different manner as in 1203. This is because DRX is an operation for reducing power consumption of the terminal. For the detailed method, refer to the following fourth embodiment. With reference to FIG. 12, UE3 is a terminal that intends to transmit sidelink data, i.e., transmit PSSCH 1205, as UE4, and at this time, UE4 may not perform sidelink DRX. In this case, UE2 may receive and decode PSCCH 1204 transmitted by UE3 during the sensing period, regardless of DRX, and perform sensing operation.

[0105] In the second embodiment, as shown in 1201 of FIG. 12, a method is provided in which a peer terminal that transmits sidelink data in a terminal that performs DRX performs Mode 2 sensing and selects resources.

[0106] FIG. 13 illustrates a resource selection window when a peer UE transmitting sidelink data in a UE performing DRX operates in Mode 2 according to an embodiment.

[0107] 13, when a peer UE that transmits sidelink data in a UE performing DRX determines a resource selection window 1300, a part of the time region of the resource selection window may correspond to the inactive time 1301 of the UE performing DRX, and another part of the time region may correspond to the active time 1302 of the UE performing DRX. As described above, the UE performing DRX may not decode control information and data information in the corresponding time period of the DRX inactive time. Therefore, if a peer UE that transmits sidelink data in a UE performing DRX transmits sidelink data in the time period corresponding to the DRX inactive time of the UE performing DRX, the UE performing DRX may not be able to receive the corresponding data.

[0108] In the present invention, it is assumed that the peer terminal knows the DRX setting information of the terminal when transmitting sidelink data to the terminal performing DRX. Therefore, it is assumed that the peer terminal can know the DRX active time or DRX inactive time of the terminal performing DRX. Specifically, in the case of broadcast or groupcast transmission, the DRX setting can be (pre-)configured when not connected to the base station, and can be configured through the SIB transmitted by the base station to be cell common when connected to the base station. In contrast, in the case of unicast transmission, the TX terminal can instruct the RX terminal to set the DRX setting through PC5-RRC, or the RX terminal can instruct the TX terminal. Therefore, it is assumed that the terminal is provided with setting information for DRX through the upper layer of the terminal, and can know the DRX setting information of the terminal that is different from its own DRX setting information through this.

[0109] When a peer terminal transmits sidelink data in a terminal performing DRX, the following resource selection method may be considered: Note that the following method is for illustrative purposes only, and the resource selection method in the present invention is not limited to the following method.

[0110] *Method 1: When the UE selects a set of candidate resources through Mode 2 operation and reports it to the upper layer of the UE, all resources included in the set must be resources included in the time interval corresponding to the DRX active time of the RX UE.

[0111] *Method 2: When the terminal selects a set of candidate resources through Mode 2 operation and reports it to the upper layer of the terminal, some of the resources included in the set may be included in the time interval corresponding to the DRX active time of the RX terminal, and some other resources included in the set may not be included in the time interval corresponding to the DRX active time of the RX terminal.

[0112] When the set of candidate resources is reported to the upper layer of the terminal from the physical layer of the terminal, the upper layer of the terminal may randomly select a transmission resource from the candidate resources included in the set of candidate resources. In this case, not only the initial transmission resource but also the retransmission resource may be selected. If the initial transmission resource and the retransmission resource are selected, the resource located earlier in time among the randomly selected resources may be the initial transmission resource and the resource located later in time may be the retransmission resource. When the method 1 is used, it is possible to ensure that the transmission resource is always selected in the DRX active time of the RX terminal, so that it is possible to prevent the sidelink data transmitted by the TX terminal from being transmitted in the DRX inactive time of the RX terminal. However, when the area corresponding to 1302 in FIG. 13 is small, it may be difficult to secure a sufficient amount of candidate resources included in the set of candidate resources. In general, when the amount of candidate resources included in the set of candidate resources is sufficiently guaranteed, when the set of candidate resources is reported to the upper layer of the terminal and random selection is performed, the probability of collision with resources selected by other terminals can be reduced. In contrast, when the method 2 is used, it is not guaranteed that the transmission resource is always selected in the DRX active time of the RX UE, so that the sidelink data transmitted by the TX UE may be transmitted in the DRX inactive time of the RX UE. However, since the candidate resource can be selected in the area of ​​1301 even if the area corresponding to 1302 in FIG. 13 is small, there may be no problem in reserving a sufficient amount of candidate resources included in the set of candidate resources.

[0113] In order to compensate for the drawbacks of the above-described method 2 when the method 2 is used, the initial transmission resource may be selected randomly from only the candidate resources included in the DRX active time among the candidate resources included in the reported set of candidate resources, and the retransmission resource may be selected randomly from all candidates included in the reported set of candidate resources. This is because the initial transmission is more important than the retransmission. For details of the method of selecting a candidate resource set in consideration of DRX when the method 2 is used, please refer to the third embodiment.

[0114] In addition, the retransmission method in the sidelink can be divided into a HARQ feedback based retransmission method and a blind retransmission method. In the HARQ feedback based retransmission method, if HARQ feedback is performed and a NACK is received after the initial transmission, retransmission is performed, otherwise retransmission is not performed. This method is possible when a PSFCH resource is configured in the resource pool, HARQ feedback is supported, and the transmitting terminal activates HARQ feedback in the SCI during sidelink transmission. However, if a PSFCH resource is not configured in the resource pool or HARQ feedback is not activated, the terminal cannot receive HARQ feedback, so in this case, the terminal can perform blind retransmission. Blind retransmission is a method in which, when a terminal selects a retransmission resource, the terminal must perform repetition transmission (repetition) on the resource. Therefore, when performing blind retransmission, when a peer terminal is a terminal performing DRX and transmits sidelink data, it is necessary to ensure that not only the initial transmission but also the retransmission is transmitted in a time period corresponding to the DRX active time of the RX terminal. In the present invention, one or more of the following conditions can be considered as conditions for using method 2. It should be noted that the present invention is not limited to the following conditions.

[0115] *Condition 1: When the terminal performs HARQ feedback-based retransmission

[0116] *Condition 2: Unicast or groupcast transmission

[0117] *Condition 3: Unicast transmission

[0118] *Condition 4: When partial sensing or random selection is performed

[0119] The condition 2 is due to the fact that HARQ feedback based retransmission is only supported in unicast or groupcast transmission. The condition 3 is to further restrict the environment in which method 2 is applied. The condition 4 may be considered when SL DRX is applied only to partial sensing or random selection, not full sensing.

[0120] FIG. 14 is a diagram illustrating that Method 2 is applied according to the above conditions according to one embodiment.

[0121] Referring to FIG. 14, if one or more of the conditions presented in 1400 are satisfied, the UE may proceed to 1401 to apply method 2. In contrast, if at least one condition is not satisfied in 1400, the UE may proceed to 1402 to apply method 1. Here, method 1 (1402) may be interpreted as a case where a subset in 1401 becomes a whole set. In other words, method 2 may include method 1. In method 2, a case may occur where some resources included in the set are not included in a time interval corresponding to the DRX active time of the SL DRX of the RX UE, and a case may occur where all resources are included in a time interval corresponding to the DRX active time of the SL DRX of the RX UE. Therefore, method 1 may be interpreted as corresponding to one of the cases of method 2.

[0122] In the third embodiment, a detailed method for selecting a set of candidate resources taking DRX into consideration when method 1 or method 2 of the second embodiment is used is proposed.

[0123] According to the existing Mode 2 resource selection method, a terminal selects a set of candidate resources (S A ) and reports it to the upper layer of the terminal, and the upper layer of the terminal randomly selects a resource from the resource candidates included in the SA. At this time, not only the initial transmission resource but also the retransmission resource can be selected. If the initial transmission resource and the retransmission resource are selected, the randomly selected resource located earlier in time can be the initial transmission resource, and the resource located later in time can be the retransmission resource. When the terminal determines a set of candidate resources (SA) through the Mode 2 procedure in the physical layer, the candidate resources are selected from all candidates (M total ) can be determined within M total DeS A The process of selecting is based on the sensing results. Also, according to the Mode2 procedure, S A ≧X M total Here, X is the number of candidate resources that correspond to S. A The factor to determine whether to include X in the resource pool can be selected from the range {0.2, 0.35, 0.5}, and can be pre-configured in the resource pool based on the priority. Here, X is provided as a physical layer in the upper layer of the terminal, and the Mode 2 procedure is performed in the physical layer. If the selection result S A <X·M total When the resource corresponding to the above is selected, the threshold of RSRP (Reference Signal Received Power) is lowered to allow for S A ≧X M total This can be guaranteed as described above. AThis is because if the amount of candidate resources included in is sufficiently guaranteed, the probability of collision with resources selected by other terminals when the set of candidate resources is reported to the upper layer of the terminal and random selection is performed can be reduced.

[0124] When DRX is not taken into consideration, in the full sensing, all slots are M within the resource selection window [n+T1, n+T2] shown in FIG. total In the case of periodic resource reservation with partial sensing, only Y slots in the resource selection window [n+T1, n+T2] can be the candidate resources included in M. total In the case of aperiodic resource reservation with partial sensing, only Y' slots in the resource selection window [n+T1, n+T2] can be the candidate resources included in M. total can be a candidate resource for inclusion in

[0125] If DRX is taken into account and method 1 is used, S A Since all resources included in the resource selection window [n+T1, n+T2] must be included in the time interval corresponding to the DRX active time of the RX terminal, unlike the conventional method, in full sensing, only slots included in the time interval corresponding to the DRX active time are selected in the resource selection window [n+T1, n+T2] shown in FIG. total In the case of periodic resource reservation with partial sensing, only Y slots included in the DRX active time in the resource selection window [n+T1, n+T2] can be the candidate resources included in M. total In the case of non-periodic resource reservation with partial sensing, only Y' slots included in the DRX active time in the resource selection window [n+T1, n+T2] can be candidate resources included in Mtotal. This allows S to be selected through the existing Mode 2 procedure. A ≧X M totalThis will allow you to select resource candidates that meet the above criteria.

[0126] In contrast, when DRX is taken into account and method 2 is used, S A Only some of the resources included in the set are included in the time interval corresponding to the DRX active time of the RX terminal, and some other resources included in the set may not be included in the time interval corresponding to the DRX active time of the RX terminal. When Method 2 is used, the existing method is performed by using the existing Mode 2 procedure. A ≧X M total If we can select resource candidates that meet the criteria, A It may be difficult to secure a certain amount of resources in the time period corresponding to the DRX active time of the RX terminal among the resources included in 1302. This is because the time period corresponding to 1302 in FIG. 13 may not be sufficiently secured, and the S A This is because many resource candidates may be eliminated in the time period corresponding to 1302 during the selection process. Therefore, it is necessary to define the Mode 2 procedure to prevent such a problem from occurring. In other words, when the method 2 is used, the S A It is necessary to ensure that a certain amount of resources included in the time period corresponding to the DRX active time of the RX terminal among the resources included in the DRX active time are secured. For this purpose, the following alternatives can be used. It should be noted that the present invention is not limited to the following alternatives.

[0127] *Alternative 1: When a peer terminal (TX terminal) transmits sidelink data through a terminal (RX terminal) that performs DRX, the peer terminal (TX terminal) AThe Mode 2 procedure is performed by separating the DRX active time of the RX terminal into two subsets. In this case, the first subset is selected based on the time region corresponding to the DRX active time of the RX terminal within the resource selection window, and the second subset is selected based on the time region corresponding to the DRX inactive time of the RX terminal within the resource selection window.

[0128] *Alternative 2: When a peer terminal (TX terminal) transmits sidelink data to a terminal (RX terminal) performing DRX, the peer terminal (TX terminal) first selects S in the time region corresponding to the DRX active time of the RX terminal within the resource selection window. A Select candidate resources in the region and perform Mode 2 procedure in the region to obtain S A ≧X M total If the above condition cannot be satisfied, the S A Select additional candidate resources from S A ≧X M total can be satisfied.

[0129] More specifically, in the case of the alternative 1, the following two detailed operations are considered.

[0130] *Alternative 1-1: All candidates in the resource selection window (M total ) is the candidate M of the time domain corresponding to the DRX active time of the RX terminal. total (1) and the candidate time region corresponding to the DRX inactive time of the RX terminal M total (2) can be determined. In this case, M total =M total (1)+M total (2) is satisfied. In the physical layer, the terminal transmits S A (1) ≧ X M total (1) and S A (2) ≧ X M total(2) can be selected from the candidate resources that fall under (X) and (S). Here, X is the number of candidate resources that fall under (S) as described above. A It is a parameter provided by the upper layer of the terminal as a factor to determine whether to include it in the A (1) is a resource candidate selected in the time region corresponding to the DRX active time, S A (2) can be interpreted as a resource candidate selected in the time domain corresponding to the DRX inactive time. Then, the UE A =S A (1)+S A (2) can be reported by the upper layer of the terminal. The upper layer of the terminal can randomly select a resource from the candidate resources belonging to the SA.

[0131] *Alternative 1-2: All candidates in the resource selection window (M total ) is determined, the terminal in the physical layer performs two Mode 2 procedures to obtain S A (1) ≥ X Y M total The resource candidates that correspond to S A (2) ≥ X (1-Y) M total Here, X is the number of candidate resources that correspond to S as described above. A Y is a parameter provided by the upper layer of the terminal as a factor to determine whether to include it in S. A In the present invention, the value of Y is not limited to a specific value as a factor for determining how many candidate resources are included in the DRX active time. The value of Y can be selected between 0 and 1. The value of Y may be a value determined by the UE implementation, a value pre-configured in the resource pool, a value independently pre-configured, or a value set through PC5-RRC. The values ​​of X and Y are provided by the upper layer of the UE, and the Mode 2 procedure is performed as described above in the physical layer to determine S. A =S A (1)+S A(2) can be reported by the upper layer of the terminal. The upper layer of the terminal can randomly select a resource from the candidate resources belonging to the SA.

[0132] Unlike Alternative 1, the operation of the terminal in Alternative 2 is described in more detail below. total When the DRX active time of the RX terminal is determined, the UE first selects S in the time region corresponding to the DRX active time of the RX terminal within the resource selection window. A However, if the time region corresponding to 1302 in FIG. 13 is not sufficiently secured, the Mode 2 procedure is performed to select candidate resources included in S A ≧X M total As described above, the result of the sensing process may not be satisfied. A <X·M total When the corresponding resource is selected, the terminal lowers the RSRP threshold and A ≧X M total However, if there are few candidate resources in the 1302 area, the RSRP threshold is not enough to guarantee the availability of S. A ≧X M total It should be noted that there may be cases where it is not possible to satisfy S. Therefore, in the alternative 2, only in such cases, S is performed in the time domain corresponding to the DRX inactive time of the RX terminal within the resource selection window. A Select additional candidate resources from S A ≧X M total This is a way to satisfy the above.

[0133] In the fourth embodiment, a detailed operation is proposed for a case where the sensing operation in the inactive time and active time of the sidelink DRX of a terminal performing sidelink DRX shown in 1203 of Fig. 12 may not be the same. This is because DRX is an operation for reducing power consumption of the terminal.

[0134] The sensing operation of a typical UE has been described with reference to Fig. 7 (full sensing), Fig. 8 (partial sensing for periodic transmission), and Fig. 9 (partial sensing for aperiodic transmission). If the UE performs sidelink DRX and operates in DRX inactive time (in other words, the UE may not decode control information and data information during this time period), the following sensing operation may be considered.

[0135] *Full sensing is not performed. In other words, partial sensing is performed.

[0136] *The value of k described in Figures 8 and 9 is always assumed to be 1. Even if pre-configured with k=2, sensing is performed only in the slot corresponding to k=1.

[0137] *CPS is not performed. In other words, only PBPS (Periodic Based Partial Sensing) is performed.

[0138] In the fifth embodiment, as described in FIG. 10, a terminal operation for performing Mode 2 through inter-terminal cooperation in the sidelink is proposed. In the existing Mode 2, a transmitting terminal that wishes to transmit sidelink data directly performs resource allocation for sidelink data transmission through sensing and resource selection operations. However, in the advanced Mode 2 scheme, another terminal other than the transmitting terminal may provide resource allocation related information at the transmitting terminal. Here, the provision of resource allocation related information at the transmitting terminal by another terminal other than the transmitting terminal can be referred to as inter-terminal cooperation. In this case, it is noted that the transmitting terminal can perform Mode 2 resource selection using both the sensing and resource selection operations of the transmitting terminal and the inter-terminal cooperation information provided by the other terminal, or can perform Mode 2 resource selection using only the inter-terminal cooperation information provided by the other terminal. In this embodiment, a method and terminal operation for indicating information when UE-A provides UE-B with a set of time-frequency resource allocation information suitable (preferable) or unsuitable (unpreferable) for transmission according to the inter-terminal cooperation method 1 described in FIG. 10 is proposed. In the present invention, the inter-terminal cooperation information can be referred to as Resource Selection Assistance Information (RSAI).

[0139] First, according to the method presented in this embodiment, when UE-A provides UE-B with a set of time-frequency resource allocation information suitable (preferable) or non-suitable (unpreferable) for transmission according to cooperation method 1 between terminals, the following two transmission methods can be considered:

[0140] *Transmission method 1: When UE-B requests UE-A for terminal cooperation, UE-A provides terminal cooperation information to UE-B.

[0141] *Transmission method 2: UE-A provides cooperation information between the terminals to UE-B when certain conditions are met.

[0142] In the case of transmission method 2, the specific condition may be a periodically set time. Then, UE-A may provide cooperation information between UEs to UE-B at the set time. However, the present invention does not limit the specific condition to this. Also, both transmission method 1 and transmission method 2 may be considered in the sidelink, or only one method may be considered.

[0143] In this embodiment, attention is focused on the transmission method 1. In the transmission method 1, the following method may be considered as a method for UE-B to request cooperation between terminals from UE-A. Note that the present invention is not limited to only the following method.

[0144] * Transmission method 1-1-1: Request cooperation information between terminals via MAC CE

[0145] *Transmission method 1-1-2:2 nd Request cooperation information between terminals through SCI

[0146] * Transmission method 1-1-3: Request cooperation information between terminals via PSFCH

[0147] 2. nd When SCI is used, this is the newly defined 2 nd In this embodiment, the above-mentioned two nd SCI format 2 nd It is called SCI format X. nd SCI format X can include not only the RSAI request, which is information requesting cooperation between terminals, but also the information included in Table 1. That is, for cooperation between terminals, UE-B converts the information provided in Table 1 by UE-A into nd It may be provided together with a request for cooperation between terminals via SCI format X.

[0148] [Table 1]

[0149] Also, a method in which UE-B requests cooperation between UEs from UE-A by combining the above methods can be considered. For example, referring to Table 1, since the RSAI request, which is information requesting cooperation between UEs, can be indicated by 1-bit information, this can be indicated through the PSFCH by transmission method 1-1-3. In contrast, since the other information shown in Table 1 is difficult to transmit through the PSFCH, it can be indicated through transmission method 1-1-2. 2nd One possible method is to transmit via SCI.

[0150] Alternatively, in transmission method 1, the following two methods may be considered as a method for UE-A to provide cooperation information between terminals to UE-B, but the present invention is not limited to only the following methods.

[0151] *Transmission method 1-2-1: Signaling cooperation information between terminals via MAC CE

[0152] * Transmission method 1-2-2: Signal cooperation information between terminals through MAC CE if the amount of cooperation information between terminals is greater than a certain threshold, otherwise, nd Cooperation information between terminals is signaled via the SCI.

[0153] 2. nd When SCI is used, this is the newly defined 2 nd This can be done through the SCI format. nd Same as SCI format2 nd It can also be determined as SCI format X, 2 nd SCI format X and another new 2 nd It can also be defined as SCI format. nd Same as SCI format2 nd If SCI format X is determined, the 2 ndIt is also possible to use a method that takes into account the type of SCI format. st 2 in SCI nd The bit that indicates the type of SCI format is 2 bits, and if this method is used, another 2 bits are used later. nd The advantage is that it leaves space for the SCI format. nd SCI format is 2 in transmission method 1-1-2 nd Same as SCI format2 nd 2 if determined to be SCI format X nd SCI format X is determined by a fixed payload size and the information used may vary depending on whether it is used in transmission method 1-1-2 or in transmission method 1-2-2. First, the 2 nd The SCI format may include the following bit fields in addition to those presented in Table 1:

[0154] [Table 2]

[0155] In Table 2, the Identifier for SCI Format may be a field that distinguishes whether the corresponding information is information requesting cooperation between terminals according to transmission method 1-1-2 or information providing cooperation information between terminals according to transmission method 1-2-2 in one band as described above. Also, in Table 2, RSAI feedback is a field corresponding to cooperation information between terminals. In the present invention, the amount of the corresponding information is not limited to a specific value.

[0156] It should be noted that according to the proposed transmission methods 1-1-1, 1-1-2, 1-1-3 to 1-2-1, 1-2-2, the sidelink terminal can indicate the information in different ways when requesting cooperation between terminals and when providing cooperation information between terminals. In one example, when the transmission method 1 is used in the sidelink transmission method, if the transmission method 1-1-2 and the transmission method 1-2-1 are considered, the terminal may indicate the information using another method according to the information for cooperation between terminals as shown in FIG. 15. The above description of the transmission method is referred to.

[0157] In the sixth embodiment, a terminal operation for performing Mode 2 through terminal cooperation in the sidelink is proposed as described in Fig. 10. According to terminal cooperation method 1 in Fig. 10, UE-A can provide UE-B with set information of time-frequency resource allocation suitable (preferable) or unsuitable (unpreferable) for transmission. In addition, as described in the fifth embodiment, the following transmission method 1 is considered.

[0158] *Transmission method 1: When UE-B requests UE-A for terminal cooperation, UE-A provides terminal cooperation information to UE-B.

[0159] In this embodiment, a condition is proposed for UE-A to request cooperation information between UEs from UE-B in the transmission method 1. Specifically, options such as those shown in Table 3 are considered.

[0160] [Table 3]

[0161] It should be noted that the present invention is not limited to the options presented above. In particular, if any one of the options other than Option 9 is a necessary and sufficient condition for UE-A to request cooperation information between UEs as UE-B, the conditions for requesting cooperation between UEs may be very restrictive. Therefore, the conditions for UE-A to request cooperation information between UEs as UE-B may be determined according to the combination of the presented options. In one example, Option 1 may be a necessary condition for UE-A to request cooperation information between UEs as UE-B. In addition, other options may be determined according to the implementation of the terminal.

[0162] In the seventh embodiment, a detailed method for selecting a set of candidate resources in consideration of DRX is proposed when the method 1 or method 2 in the second embodiment is used. In addition, in the seventh embodiment, a method for utilizing the method proposed in the third embodiment and an additional method for selecting a set of candidate resources in consideration of DRX are proposed.

[0163] First, method 1 or method 2 in the second embodiment is as follows. The present invention is not limited to the following methods.

[0164] *Method 1: When the UE selects a set of candidate resources through Mode 2 operation and reports it to the upper layer of the UE, all resources included in the set must be resources included in the time interval corresponding to the DRX active time of the RX UE.

[0165] *Method 2: When a terminal selects a set of candidate resources through Mode 2 operation and reports it to the upper layer of the terminal, some of the resources included in the set may be included in the time interval corresponding to the DRX active time of the RX terminal, and some other resources included in the set may not be included in the time interval corresponding to the DRX active time of the RX terminal.

[0166] In sidelink Mode 2 transmission, the TX terminal selects a transmission resource for periodic transmission and sets a reservation interval (or periodicity) P rsvp_TX SCI(1 st There is a method to reserve transmission resources periodically by instructing it with the P rsvp_TX can have various values ​​such as 0, 1:99, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000. In contrast, the TX terminal selects a transmission resource for aperiodic transmission and SCI(1 st Through SCI rsvp_TX One way to do this is to set it to 0 to perform periodic transmission.

[0167] DRX in the sidelink can be operated by setting DRX-related parameters as shown in FIG. 11 in consideration of periodic transmission of the TX terminal. Therefore, the TX terminal selects a transmission resource for periodic transmission and performs periodic transmission (P rsvp_TX ≠ 0), the TX terminal is SCI(1 st A method can be considered in which the slots in which transmission resources are periodically reserved through the SCI are regarded as DRX active time by the RX terminal. According to this method, even if a candidate resource selected from a set of candidate resources reported to the UE upper layer through sensing in the physical layer is included in a time period corresponding to DRX inactive time, if the resource is selected and transmitted, the periodically reserved resource is regarded as DRX active time by the RX terminal, and no problem occurs in the RX terminal receiving data transmitted by the TX terminal, so that the method 1 or 2 of the second embodiment may not be necessary. However, if the TX terminal still performs aperiodic transmission (P rsvp_TX=0), the method 1 or method 2 of the second embodiment presented above should be considered.

[0168] FIG. 18 is a diagram illustrating a terminal operation depending on whether a TX terminal performs periodic transmission according to an embodiment.

[0169] FIG. 18 shows a case where a TX terminal selects a transmission resource for periodic transmission and executes periodic transmission (P rsvp_TX ≠ 0), the TX terminal is SCI(1 st The slots in which transmission resources are periodically reserved via the SCI can be applied to the RX UE when it is considered as DRX active time.

[0170] Referring to FIG. 18, in 1800, the TX terminal selects a transmission resource for periodic transmission and performs periodic transmission (P rsvp_TX ≠0), the terminal can move to 1801 and report the selected candidate resources to the terminal upper layer using the existing Mode 2 method. The existing Mode 2 method may be a method of selecting candidate resources regardless of the sidelink DRX configuration. According to this method, the terminal may not adjust the candidate resources to be included in the DRX active time in the process of selecting the candidate resources. On the other hand, if the condition is not satisfied in 1800, in other words, the TX terminal performs aperiodic transmission (P rsvp_TX =0), the procedure proceeds to 1802, where the selected candidate resources can be reported to the upper host of the terminal using the modified Mode 2 method. The modified Mode 2 method is different from the existing Mode 2 method in that it selects candidate resources taking into account the sidelink DRX configuration. For example, the method 1 or method 2 of the second embodiment can be applied.

[0171] In the following embodiment, a more specific terminal operation corresponding to 1802 in FIG. 18 is proposed. However, it should be noted that the present invention is not limited to the following alternatives. Furthermore, the following alternatives may be used in combination. In addition, the terminal operation to be used among the following alternatives may be (pre-)configured.

[0172] First, in the first alternative, before selecting candidate resources using the sensing result, at least N candidate resources (N slots) among the resource selection candidate resources in the resource selection window [n+T1, n+T2] are restricted to be in the DRX active time. For details on the resource selection window, please refer to Figures 7 to 9. Specifically, in full sensing, as shown in Figure 7, M total (Before selecting candidate resources using the sensing result, N candidate resources (N slots) out of the total (number of candidate resources) candidate resources can be limited to be in the DRX active time. In the case of performing periodic resource reservation with partial sensing as shown in FIG. 8 (P rsvp_TX ≠0) N candidate resources (N slots) in Y slots in the resource selection window [n+T1, n+T2] can be restricted to be in the DRX active time. rsvp_TX ≠0) In the Y' slots in the resource selection window [n+T1, n+T2], N candidate resources (N slots) can be restricted to be in the DRX active time. totalIt should be noted that N may be the total number of candidate resources before selecting candidate resources using the sensing result. In the above alternative, the value of N may be pre-configured, and the range of values ​​that can be set as the value of N in the present invention is not limited to a specific value. In addition, the N candidate resources may be limited to resources located earlier in time. In addition, the N candidate resources may be M after full sensing. total , and with partial sensing, N=Y or N=Y'.

[0173] In the second alternative, the physical layer uses the sensing results to determine a set of candidate resources (S A ) and report it to the upper layer of the terminal. A This is a method of restricting the number of candidate resources included in S to at least K (K slots) in the DRX active time. A All candidate resources of X N may be in the DRX active time. total Here, we can select candidate resources that correspond to N total is S A X represents the number of all candidate resources corresponding to the DRX active time among the candidate resources included in N total It is a parameter provided by the upper layer of the terminal as a factor indicating how many candidate resources to select from among X. For example, X can be selected from values ​​corresponding to {0.2, 0.35, 0.5} and can be pre-configured in the resource pool based on the priority. If the selection result through sensing is X·N total When fewer resources are selected, the RSRP (Reference Signal Received Power) threshold is lowered to X·N totalThis is because only when the amount of candidate resources is sufficiently guaranteed can the probability of collision with resources selected by other terminals be reduced when the set of candidate resources is reported by the upper layer of the terminal and random selection is performed. total The selection and reporting of resource candidates that fall under the category of S will be carried out through the existing Mode 2 procedure. A It could also be interpreted as a separate operation from the operation of determining and reporting to upper layers of the terminal.

[0174] The transmitter, receiver, and processor of a terminal and a base station for carrying out the above-mentioned embodiment of the present invention are respectively shown in Figures 16 and 17. In the above-mentioned embodiment, a method for a terminal to perform multiple antenna transmission and reception in a sidelink is shown, and in order to do this, the receiver, processor, and transmitter of the base station and the terminal must operate according to the respective embodiment.

[0175] Specifically, FIG. 16 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention. As shown in FIG. 16, the terminal of the present invention may include a terminal receiver 1600, a terminal transmitter 1604, and a terminal processor 1602. The terminal receiver 1600 and the terminal may be commonly referred to as a transmitter / receiver in the embodiment of the present invention. The transmitter / receiver may transmit and receive signals with a base station. The signals may include control information and data. To this end, the transmitter / receiver may include an RF transmitter that up-converts and amplifies the frequency of a signal to be transmitted, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. In addition, the transmitter / receiver may receive a signal through a wireless channel and output it to the terminal processor 1602, and transmit the signal output from the terminal processor 1602 through a wireless channel. The terminal processor 1602 may control a series of processes so that the terminal operates according to the above-mentioned embodiment of the present invention.

[0176] FIG. 17 is a block diagram showing an internal structure of a base station according to an embodiment. As shown in FIG. 17, the base station of the present invention may include a base station receiver 1701, a base station transmitter 1705, and a base station processor 1703. The base station receiver 1701 and the base station transmitter 1705 may be collectively referred to as a transceiver in the embodiment of the present invention. The transceiver may transmit and receive signals to and from a terminal. The signals may include control information and data. To this end, the transceiver may include an RF transmitter that up-converts and amplifies the frequency of a signal to be transmitted, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. In addition, the transceiver may receive a signal through a wireless channel and output it to the base station processor 1703, and transmit the signal output from the terminal processor 1703 through a wireless channel. The base station processor 1703 may control a series of processes so that the base station operates according to the above-mentioned embodiment of the present invention.

[0177] Meanwhile, the embodiments of the present invention disclosed in this specification and drawings are merely specific examples presented to easily explain the technical contents of the present invention and to facilitate understanding of the present invention, and are not intended to limit the scope of the present invention. That is, it is obvious to a person skilled in the art to which the present invention belongs that other modifications can be implemented based on the technical ideas of the present invention. Also, the above-mentioned respective embodiments can be operated in combination with each other as necessary. For example, all the embodiments of the present invention can be partially combined with each other to operate a base station and a terminal.

[0178] Although the present invention has been described with reference to various embodiments, various modifications can be made without departing from the spirit and scope of the present invention, which is defined by the appended claims and their equivalents, other than the detailed description and embodiments. [Explanation of symbols]

[0179] 1600 Terminal receiver 1602 Terminal processing unit 1604 Terminal transmitter 1701 Base station receiver 1703 Base station processing unit 1705 Base station transmitter

Claims

1. A method performed by a first user equipment (UE) in a communication system, comprising: transmitting a first sidelink control information (SCI) requesting inter-UE coordination information (inter-UE coordination information) to a second UE; receiving a second SCI from the second UE, the second SCI providing cooperation information between the terminals; The method of claim 1, wherein the first SCI includes a field indicating that the first SCI is used to request cooperation information between the terminals.

2. The first SCI and the second SCI correspond to the same SCI format, and the SCI format is a two-stage (2-phase) SCI format transmitted through a physical sidelink shared channel (PSSCH). ｎｄ 2. The method according to claim 1, characterized in that the SCI is a 3-stage SCI.

3. The method of claim 1 , wherein the second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals.

4. 2. The method of claim 1, wherein the bit size of said field is 1 bit.

5. A method performed by a second user equipment (UE) in a communication system, comprising: receiving sidelink control information (SCI) from a first UE requesting inter-UE coordination information; and transmitting a second SCI to the first UE, the second SCI providing cooperation information between the terminals; The method of claim 1, wherein the first SCI includes a field indicating that the first SCI is used to request cooperation information between the terminals.

6. The first SCI and the second SCI correspond to the same SCI format, and the SCI format is a two-stage (2-phase) SCI format transmitted through a physical sidelink shared channel (PSSCH). ｎｄ 6. The method according to claim 5, characterized in that the SCI is a 3-stage SCI.

7. The method of claim 5, wherein the second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals.

8. 6. The method of claim 5, wherein the bit size of the field is 1 bit.

9. A first user equipment (UE) in a communication system, A transmitting / receiving unit; A controller configured to transmit a first sidelink control information (SCI) requesting inter-UE coordination information to a second UE and receive a second SCI providing the inter-UE coordination information from the second UE, The first SCI includes a field indicating that the first SCI is used to request cooperation information between the terminals.

10. The first SCI and the second SCI correspond to the same SCI format, and the SCI format is a two-stage (2-phase) SCI format transmitted through a physical sidelink shared channel (PSSCH). ｎｄ The first UE according to claim 9, characterized in that the first UE is a -stage) SCI.

11. The first UE of claim 9, wherein the second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals.

12. The first UE of claim 9, wherein the field has a bit size of 1 bit.

13. A second UE (user equipment) in a communication system, A transmitting / receiving unit; A controller configured to receive a first sidelink control information (SCI) requesting inter-UE coordination information from a first UE and to transmit a second sidelink control information (SCI) providing the inter-UE coordination information to the first UE; The first SCI includes a field indicating that the first SCI is used to request cooperation information between the terminals.

14. The first SCI and the second SCI correspond to the same SCI format, and the SCI format is a two-stage (2-phase) SCI format transmitted through a physical sidelink shared channel (PSSCH). ｎｄ The second UE according to claim 13, characterized in that the SCI is a -stage) SCI.

15. The second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals; The second UE according to claim 13, wherein the bit size of the field is 1 bit.

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