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 sidelink. [Background technology]

[0002] 4G(4 th Improved 5G (5G) technology has been developed to meet the increasing demand for wireless data traffic since the commercialization of the 5G (5th generation) communication system. thEfforts are underway to develop a 5G (Next Generation) communication system or pre-5G communication system. For this reason, 5G communication systems or pre-5G communication systems are also called beyond-4G network (Beyond 4G Network) communication systems or post-LTE (Long Term Evolution) systems. To achieve high data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., the 60 GHz band). To mitigate propagation path loss and increase transmission distance in ultra-high frequency bands, beamforming, massive multiple-input multiple-output (MM-MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antenna technologies are being discussed for 5G communication systems. Furthermore, to improve the system's network, technologies such as advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication, wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Point), and receiver interference cancellation are being developed for the 5G communication system.In addition, advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding) are being developed for 5G systems, as well as advanced connection technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access).

[0003] Meanwhile, the Internet, a human-centered network where humans generate and consume information, is evolving into the Internet of Things (IoT), a network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology has also emerged, combining IoT technology with big data processing technology through connections to cloud servers. Realizing the IoT requires technological elements such as sensing technology, wired / wireless communications and network infrastructure, service interface technology, and security technology. Recently, research has focused on sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) for connecting objects. In an IoT environment, intelligent IT (Internet Technology) services can be provided that create new value in people's lives by collecting and analyzing data generated by connected objects. Through the convergence and integration of existing IT (information technology) technologies and various industries, the IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services.

[0004] As a result, various attempts are being made to apply 5G communication systems (fifth generation communication systems 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 through 5G communication technologies 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 and IoT technologies.

[0005] As described above, as various services become available with the development of wireless communication systems, a method for smoothly providing these services is required.

[0006] The above information is provided solely for background information to aid in understanding the present disclosure, and 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 in a vehicle terminal supporting V2X when the terminal exchanges information with other vehicle terminals and pedestrian mobile terminals using a sidelink. In particular, the present invention relates to a resource selection method when the terminal performs discontinuous reception (DRX), and 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, in which 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 from the second UE, the second SCI providing the inter-UE coordination information, and the first SCI includes a field indicating that the first SCI is used to request the inter-UE coordination information.

[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, wherein the second UE receives a first sidelink control information (SCI) requesting inter-UE coordination information from a first UE, the second UE transmits a second SCI providing the inter-UE coordination information to the first UE, and the first SCI includes a field indicating that the first SCI is used to request the inter-UE coordination information.

[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 unit 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 inter-UE coordination information from the second UE. The first SCI includes a field indicating that the first SCI is used to request the inter-UE coordination information.

[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, from a first UE, sidelink control information (SCI) requesting inter-UE coordination information, and to transmit, to the first UE, a second SCI providing the inter-UE coordination information. The first SCI includes a field indicating that the first SCI is used to request the inter-UE coordination information. [Effects of the Invention]

[0012] The present invention proposes a resource selection method when discontinuous reception (DRX) is performed between terminals in sidelink communication. It also proposes a resource selection method through cooperation between terminals. The proposed method can be effectively used to minimize power consumption of terminals. Furthermore, the proposed method can improve resource allocation performance. [Brief explanation 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. [Figure 2] 1 is a diagram illustrating a V2X communication method performed through a sidelink according to an embodiment. [Figure 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. 10 is a sequence diagram illustrating a method for a base station to allocate transmission resources in a sidelink according to an embodiment. [Figure 5]FIG. 10 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. [Figure 6] 1 is a diagram illustrating a mapping structure of physical channels 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 terminal 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 illustrating the inactive time (or off-duration) and active time (or on-duration) of discontinuous reception (hereinafter, referred to as DRX) determined by parameters configured for DRX when DRX is performed in a sidelink according to one embodiment. [Figure 11b] 1 is a diagram illustrating the inactive time (or off-duration) and active time (or on-duration) of discontinuous reception (hereinafter, referred to as DRX) determined by parameters configured for DRX when DRX is performed in a sidelink according to one embodiment. [Figure 11c]1 is a diagram illustrating the inactive time (or off-duration) and active time (or on-duration) of discontinuous reception (hereinafter, referred to as DRX) determined by parameters configured for DRX when DRX is performed in a sidelink according to one embodiment. [Figure 11d] 1 is a diagram illustrating the inactive time (or off-duration) and active time (or on-duration) of discontinuous reception (hereinafter, referred to as DRX) determined by parameters configured for DRX when DRX is performed in 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] 10 is a diagram illustrating 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] 10 is a diagram illustrating an example of a resource selection method when a peer UE transmits sidelink data in a UE performing DRX according to an embodiment. [Figure 15] 10 is a diagram illustrating a method for transmitting cooperation information from a terminal according to information for cooperation between terminals; [Figure 16] FIG. 2 is a block diagram showing the configuration of a terminal according to an embodiment. [Figure 17] FIG. 2 is a block diagram illustrating 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 INVENTION

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

[0015] In the accompanying drawings, some components may be exaggerated, omitted, or shown schematically, and the size of each component may not entirely reflect the actual size.

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

[0017] It will be understood that the combination of each block of the process flowchart and the flowchart figures can be implemented by computer program instructions. These computer program instructions can be loaded onto a processor in a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that the instructions, executed by the processor of the computer or other programmable data processing device, create means for performing the functions described in the flowchart blocks. These computer program instructions can also be stored in computer-usable or computer-readable memory that can direct the computer or other programmable data processing device to implement functions in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory can produce an article of manufacture containing instruction means for performing the functions described in the flowchart blocks. Computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are performed on the computer or other programmable data processing device, creating a computer-implemented process that causes the computer or other programmable data processing device to operate, and the instructions can provide steps for performing the functions described in the flowchart 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. Also, it should be noted that in some alternative implementations, the functions described in the blocks may occur out of order. For example, two blocks shown adjacently may actually be performed substantially simultaneously, or the blocks may sometimes be performed in reverse order depending on the corresponding function.

[0019] The term "module" used in this embodiment refers to software or hardware components such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit), 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 on an addressable storage medium or to implement one or more processors. Thus, by way of example, the term "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 functions provided within the components and "modules" may be combined into fewer components and "modules" or further separated into additional components and "modules." Furthermore, the components and "modules" may be embodied to implement one or more central processing units (CPUs) within a device or a secure multimedia card. Also, in the embodiments, a "unit" may include one or more processors.

[0020] In describing the embodiments of the present disclosure in detail, the main focus will be on the New RAN (NR), a radio access network based on the 5G mobile communication standard disclosed by 3GPP (registered trademark) LTE (3rd generation partnership project), and the packet core (5G System or 5G Core Network, or NG Core: next generation core), which is a core network. 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, to support network automation, a network data collection and analysis function (NWDAF) can be defined, which is a network function that analyzes and provides data collected in the 5G network. The NWDAF can collect, store, and 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 standard for a similar system) may be used below. 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 designating network entities, terms for designating messages, terms for designating interfaces between network entities, terms for designating various identification information, etc. used in the following description are provided for the convenience of explanation, and are not limited to the terms used in this disclosure, but other terms for designating objects having equivalent technical meanings may be used.

[0024] Efforts are underway to develop an improved 5G (New Radio) communication system 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 mmWave (mmWave) bands (e.g., the 28 GHz frequency band). To mitigate propagation path loss and increase propagation distance in ultra-high frequency bands, 5G communication systems are being considered, including analog beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antenna technologies. Furthermore, unlike LTE, the 5G communication system supports various subcarrier spacings, including 15 kHz, 30 kHz, 60 kHz, and 120 kHz. The physical control channel uses polar coding, and the physical data channel uses low-density parity check (LDPC). 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 in units of TB (Transport Block), but 5G can additionally support HARQ retransmission based on CBG (Code Block Group), which includes a bundle of CB (Code Block).

[0025] In addition, to improve the system's 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] As such, multiple services can be provided to users in a communication system. To provide these multiple services to users, a method and device using the same are required that can provide each service within the same time period while meeting the characteristics of the service. Research is underway into various services to be provided in 5G communication systems, one of which is a service that satisfies the requirements of low latency and high reliability. In particular, for vehicular communications, NR V2X systems support unicast communication, groupcast (or multicast) communication, and broadcast communication between terminals. Furthermore, 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 sensors, 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 UEs. In the present invention, the information shared for inter-UE coordination 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 UEs to request or provide inter-UE coordination information.

[0028] In particular, discontinuous reception (DRX) between terminals can be considered in sidelink communication. When DRX is applied, power consumption of the terminal can be minimized to improve battery efficiency. Specifically, power consumption of the terminal can be generated as follows:

[0029] *Control information transmitted through PSCCH (physical sidelink control channel)1 st SCI Decoding: The 1st SCI contains the scheduling information of the terminal. 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 during the time interval 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 during the time interval set as the active time. Therefore, successful data reception by the receiving terminal can be guaranteed only when the transmitting terminal transmits data during the period set as the DRX active time of the receiving terminal. In other words, when the transmitting terminal transmits data during the 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. Taking this into consideration, 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, particularly 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, (a) shows an example in which all V2X terminals (UE-1 and UE-2) are located within the coverage of a 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, (b) illustrates an example in which one V2X terminal, UE-1, is located within the coverage of a base station and one, UE-2, is located outside the coverage of the base station. That is, (b) illustrates an example of partial coverage (PC) in which a 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 via a downlink or transmit data and control information to the base station via 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 via a downlink or transmit data and control information to the base station via an uplink. The V2X terminal, UE-2, can transmit / receive data and control information for V2X communication with the V2X terminal, UE-1, via a sidelink.

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

[0038] Referring to FIG. 1, (d) illustrates an example of a scenario in which V2X communication is performed between V2X terminals (UE-1, UE-2) located in different cells. Specifically, (d) illustrates a case in which the V2X terminals (UE-1, UE-2) are connected (RRC connected state) or camped (RRC disconnected state or RRC idle state) to different base stations. In this case, the V2X terminal (UE-1) may be a V2X transmitter terminal, and the V2X terminal (UE-2) may be a V2X receiver terminal. Alternatively, the V2X terminal (UE-1) may be a V2X receiver terminal, and the V2X terminal (UE-2) may be a V2X transmitter terminal. The V2X terminal (UE-1) can receive a system information block (SIB) from the base station to which it is connected (or camped), and the V2X terminal (UE-2) can receive an 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. In addition, 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 signaled, and an additional method for analyzing the SIB information transmitted from each different cell may be required.

[0039] For convenience of explanation, FIG. 1 illustrates a V2X system composed of V2X terminals (UE-1, UE-2). However, communication between more V2X terminals is not limited thereto. Furthermore, the interface (uplink and downlink) between a base station and a V2X terminal may be referred to as a Uu interface, and the sidelink between the V2X terminals may be referred to as a PC5 interface. Therefore, these terms may be used interchangeably in the present disclosure. Meanwhile, in the present disclosure, the terminal may include a vehicle supporting vehicular-to-vehicular (V2V) communication, a vehicle or pedestrian headset (e.g., a smartphone) supporting vehicular-to-pedestrian (V2P) communication, a vehicle supporting vehicular-to-network (V2N) communication, or a vehicle supporting vehicular-to-infrastructure (V2I) communication. 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 some base station functions and some 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 also be referred to as an RSU.

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

[0042] Referring to FIG. 2(a), one-to-one communication can be performed between UE-1 (201, e.g., TX terminal) and UE-2 (202, e.g., RX terminal), which can be called unicast communication.

[0043] Referring to Figure 2(b), a TX terminal and an RX terminal can communicate one-to-many, which can be called groupcast or multicast. In Figure 2(b), UE-1 (211), UE-2 (212), and UE-3 (213) form one group (Group A) and perform groupcast communication, while 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. Although Figure 2(b) shows two groups (Group A and Group B) formed, this is not limiting.

[0044] Meanwhile, although not shown in Figure 2, the V2X terminals 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. For example, if UE-1 (211) is assumed to be a transmitting terminal for broadcast in Figure 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 the data and control information transmitted by UE-1 (211).

[0045] Unlike LTE V2X, NR V2X can support a mode in which a vehicular terminal transmits data to only one specific node through unicast, and a mode in which a vehicular terminal transmits data to a number of specific nodes through groupcast. For example, these unicast and groupcast technologies can be useful in service scenarios such as platooning, a technology in which two or more vehicles are connected to one network and move as 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 may be required for the leader node to simultaneously control 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 in time and frequency used for sidelink transmission and reception according to one embodiment.

[0047] The resource allocation unit on the time axis of a resource pool can be a slot. The resource allocation unit on the frequency axis can be a sub-channel consisting of one or more physical resource blocks (PRBs). Although the present disclosure describes an example in which resource pools are allocated discontinuously in time, the resource pools may also be allocated contiguously in time. Furthermore, the present disclosure describes an example in which resource pools are allocated contiguously in frequency, but a method in which resource pools are allocated discontinuously in frequency 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 slots is also illustrated. First, a sidelink slot can be defined among slots used in the uplink. Specifically, the length of symbols used in the sidelink within one slot can be set as sidelink BWP (Bandwidth Part) information. Therefore, among slots used in the uplink, slots that do not guarantee the symbol length set as the sidelink cannot become sidelink slots. 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.

number

number

[0049] Referring to 303 in FIG. 3, an example is shown in which a resource pool is allocated contiguously in frequency. Resource allocation in the frequency axis may be set as sidelink BWP (Bandwidth Part) information and may be in sub-channel units. A sub-channel may be defined as a resource allocation unit in frequency composed of one or more PRBs (Physical Resource Blocks). That is, a sub-channel may be defined as an integer multiple of the PRB. Also referring to 303, a 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 sub-channel size may be set differently. Although one sub-channel is generally composed of consecutive PRBs, it does not necessarily have to be composed of consecutive PRBs. A sub-channel may be the basic unit of resource allocation for a PSSCH. In 303, startRB-Subchannel may indicate the start position of a sub-channel in frequency 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 starting RB (Resource Block) index of the subchannel (startRB-Subchannel), information on how many PRBs the subchannel consists 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] The method by which a base station allocates transmission resources for the sidelink is referred to as Mode 1 below. Mode 1 may be scheduled resource allocation. Mode 1 may refer to a method in which a base station allocates resources used for sidelink transmission to an RRC-connected terminal using a dedicated scheduling scheme. Mode 1 allows the base station to manage sidelink resources, which is effective for interference management and resource pool management.

[0052] 4, a transmitting terminal 401 (Tx UE) can camp on a base station (cell or gNB) 403 (405). 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 needed to receive system information, paging information, etc.

[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). Conversely, 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 the sidelink when 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 the sidelink even when the Uu-RRC connection procedure 420 between the base station 403 and the receiving terminal 402 is not performed.

[0057] The transmitting terminal 401 can request transmission resources from the base station 403 for V2X communication with the receiving terminal 402 (430). At this time, the transmitting terminal 401 can request sidelink transmission resources 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 indicating 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 can request sidelink resources through a scheduling request (SR) bit transmitted over 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. In this case, the base station can allocate resources for one TB through DCI. The sidelink scheduling information for one TB included in the DCI may include parameters related to the transmission time and frequency allocation location information of the initial transmission and retransmission resources. When resources are allocated using the configured grant method, the transmission time (occasion) and frequency allocation location of the 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. The DCI for the configured grant method can be CRC scrambled with the SL-SPS-V-RNTI to indicate that it is a configured grant method. In addition, the configured grant (CG) method can be divided into Type 1 CG and Type 2 CG. In the case of Type 2 CG, the configured grant and set resources can be activated / deactivated through the DCI.

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

[0062] Specifically, the DCI (Downlink Control Information) used by the base station 403 for sidelink communication to the transmitting terminal 401 may be DCI format 3_0 or DCI format 3_1. DCI format 3_0 can be defined as DCI for scheduling an NR sidelink in one cell, and DCI format 3_1 can 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 configuration 415 for the sidelink. In contrast, in the case of unicast or groupcast transmission, the transmitting terminal 401 can also perform a one-to-one RRC connection with another terminal. 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 sends 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 stage) can be sent (470). st The stage SCI contains information related to resource allocation. ndThe stage SCI can contain other control information. The transmitting terminal 401 can also transmit data to the receiving terminal 402 through the PSSCH (480). At this time, the SCI (1 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, the method in which the UE 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 the system information, and the transmitting terminal (Tx UE) 501 can select transmission resources according to the determined rules. Unlike Mode 1 in which the base station is directly involved in resource allocation, in Figure 5, the transmitting terminal 501 autonomously selects resources based on the resource pool previously received through system information to transmit data.

[0067] Referring to Figure 5, a transmitting terminal 501 can camp on a base station 503 (505). The camp on can refer to, for example, a state in which a terminal in an idle state (RRC_IDLE) can select (or reselect) a base station (cell) as needed and receive system information or paging information. Also, referring to Figure 5, unlike Figure 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). However, 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 the receiving terminal (Rx UE) 502 is located within the coverage of the base station (cell) 503, the receiving terminal 502 can camp on the base station 503 (507). Conversely, 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, the receiving terminal 502 refers to a terminal that receives data transmitted by the 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, while in FIG. 5, the terminal can also operate in idle mode 520 (RRC disconnected state). Also, even in the RRC connected state 520, the base station 503 is not directly involved in resource allocation, and the transmitting terminal 501 can autonomously select transmission resources. 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 configured in the transmitting terminal 501 through system information received from the base station 503, and the transmitting terminal 501 can directly select time / frequency domain resources from the configured resource pool through sensing (530). When resources are finally selected, the selected resources are determined by a grant for sidelink transmission.

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

[0073] Next, the transmitting terminal 501 sends 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 stage) can be sent (560). st The stage SCI contains information related to resource allocation. nd The stage SCI can contain other control information. In addition, 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) that the transmitting terminals 401 and 501 use for sidelink communication with the receiving terminals 402 and 502 is SCI(1 st stage) and SCI format 1-A are sufficient. Also, SCI(2 nd stage) and SCI format2-A or SCI format2-B are sufficient. ndIn the SCI format 2-A, when HARQ feedback is not used or when HARQ feedback is used and includes both ACK and NACK information, SCI format 2-A can be used to include information for PSSCH decoding. In contrast, when HARQ feedback is not used or when HARQ feedback is used and includes only NACK information, SCI format 2-B can be used to include information for PSSCH decoding. For example, SCI format 2-B can be used limited to groupcast transmission.

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

[0076] Specifically, Figure 6 illustrates mapping for PSCCH / PSSCH / PSFCH physical channels. In the case of PSFCH, if sidelink HARQ feedback is activated at a higher layer, the time resources of the PSFCH can be pre-configured using resource pool information. Here, the time resources for transmitting the PSFCH can be pre-configured to one of 0, 1, 2, and 4 slots. Here, '0' means that the PSFCH resource is not used. And 1, 2, and 4 can mean that the PSFCH resource is transmitted every 1, 2, and 4 slots, respectively. Figure 6(a) illustrates the structure of a slot in which no PSFCH resource is configured, and Figure 6(b) illustrates the structure of a slot in which a PSFCH resource is configured. The PSCCH / PSSCH / PSFCH can be allocated to one or more subchannels in frequency. For details on subchannel allocation, refer to the description of Figure 3. Next, referring to FIG. 6 to explain the time mapping of the PSCCH / PSSCH / PSFCH, one or more symbols before the transmitting terminal transmits the PSCCH / PSSCH / PSFCH (physical sidelink feedback channel) in a corresponding slot 601 can be used in an area 602 for automatic gain control (AGC). When the corresponding symbol is used for AGC, a method of repeatedly transmitting a signal of another channel in the corresponding symbol area can be considered. In this case, the repeated signal of another channel can be considered as a PSCCH symbol or a portion of a PSSCH symbol. Alternatively, a preamble can be transmitted in the AGC area. When a preamble signal is transmitted, the AGC execution time can be shortened more than when a signal of another channel is repeatedly transmitted.When a preamble signal is transmitted for AGC, a specific sequence can be used as the preamble signal 602, and in this case, sequences such as PSSCH DMRS (demodulation reference signal), PSCCH DMRS, and CSI-RS (channel state information reference signal) can be used in the preamble. In this disclosure, the sequences used in the preamble are not limited to the above examples. Additionally, according to FIG. 6, control information related to resource allocation is 1 in the first symbol of the slot. st The other control information is transmitted to PSCCH603 in stage SCI (sidelink control information). nd The control information can be transmitted in the PSSCH area 604 in the stage SCI. The data scheduled by the control information can be transmitted in the PSSCH 605. nd The time position at which the stage SCI is transmitted may be mapped from the symbol at which the first PSSCH DMRS 606 is transmitted. The time position at which the PSSCH DMRS 606 is transmitted may vary depending on whether the PSFCH is transmitted or not, as shown in Figures 6(a) and 6(b). Figure 6(a) illustrates that the PSFCH 607 (physical sidelink feedback channel), a physical channel for transmitting feedback information, is located at the end of the slot. A predetermined guard interval is secured between the PSSCH 605 and the PSFCH 607 so that the UE that transmitted or received the PSSCH 605 can prepare to transmit or receive the PSFCH 607. In addition, a guard interval can be secured for a certain period of time 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 the 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 [n-T0, nT proc,0 ], where T0 is the start time of the sensing window and can be pre-configured in the resource pool information. T0 can be defined as a positive integer in ms. The present disclosure does not limit T0 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. 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 can be determined as [n+T1, n+T2], where T1 is a value in units of slots, and T1≦T proc,1 can be selected for terminal implementation. proc,1 can be defined as a maximum reference value that takes into account the processing time required to select a resource. For example, T proc,1 can be defined as different values ​​depending on the SCS (Subcarrier Spacing) in slot units. proc,1 The value set is not limited to a specific value. Also, T2 is a slot unit value. 2min The terminal can select within the range that satisfies ≦T2≦Remaining Packet Delay Budget (PDB). 2minis to prevent the terminal from selecting a value of T2 that is too small. 2min The value is determined by the priority (prioTX) of the transmitting terminal and the SCS. 2min (prio TX )' can be set in the upper layer. The terminal can select a transmission resource within the resource selection window 702.

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

[0081] 8 to 9 illustrate a method for 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 for determining slots for 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 windows (801 to 901) can be determined as described in FIG. 7 through 702.

[0082] First, referring to FIG. 8, one method of performing partial sensing is presented. The method presented in 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 in FIG. 8 may be referred to by other terms. Referring to FIG. 8, Y (≧1) candidate slots can 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 can be (pre-)configured. The final selection of the value of Y and which slot is selected can be determined by the UE implementation. At this time, one of the Y candidate slots is selected as shown in 802.

number

number

number

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

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

[0085] *Method 3: Use the common divisor of the values ​​included in sl-ResoureReservePeriodList

[0086] moreover,

number

number

[0087] Referring to Figure 9, another method for performing partial sensing is presented. The method presented in Figure 9 is a partial sensing method for aperiodic transmission, which is different from the partial sensing for periodic transmission of Figure 8, and can be applied when periodic resource reservation is not performed. Unlike Figure 8, Y' (≥ 1) candidate slots can be selected in the resource selection window (901, RSW). At this time, the Y' candidate slots can be selected time-consecutively or non-consecutively in the resource selection window. The minimum value of Y' can be (pre-)configured. The final selection of the Y' value and which slot is selected 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 inter-UE cooperation method 1 (1001), UE-A may provide UE-B with set information 1003 of time-frequency resource allocations that are suitable (preferable) or unsuitable (unpreferable) for transmission. In contrast, according to inter-UE cooperation method 2 (1002), UE-A may provide UE-B with only the compatibility of resources reserved by UE-B in the SCI. In the inter-UE cooperation method 1, UE-A must signal the set information 1003 of time-frequency resource allocations to UE-B, which may increase signaling overhead compared to inter-UE cooperation method 2. In the inter-UE cooperation method 2, UE-A signals to UE-B only the compatibility of resources reserved by UE-B in the SCI, so compatibility may be indicated by, for example, 1-bit information.

[0090] FIG. 11 is a diagram illustrating the inactive time (or off-duration) and active time (or on-duration) of discontinuous reception (hereinafter, referred to as 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 the period corresponding to the active time of DRX. Alternatively, the UE may not decode control information and data information for data reception in the period corresponding to the inactive time of DRX. In the sidelink, the control information transmitted through the PSCCH is 1 st 2, which is control information transmitted via SCI and PSSCH. nd There is an SCI. In addition, data information can be transmitted via 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. Note that some of the following parameters may not be used for sidelink DRX.

[0092] DRX related parameters

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

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

[0096] *drx-HARQ-RTT-Timer: When a retransmission is performed on the sidelink, the UE 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 receiving sidelink control information, or receiving sidelink control information and then transmitting sidelink control information (1 st If 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 this information. When the drx-HARQ-RTT-Timer 1105 expires, the UE can operate in the DRX active time 1111 to receive 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 for initial transmission and retransmission resources (including information on the existence 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 this information. st It can also be assumed and defined as the time gap between the initial transmission and the retransmission resource 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 controlled is shown in Figure 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 interval 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 such a case, the drx-RetransmissionTimer 1105 may not be defined. This is not a limitation of the present invention. 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 interval of the drx-RetransmissionTimer 1106 is set to the DRX active time 1112, allowing the peer UE to receive retransmissions. In addition, the remaining drx-cycle interval 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 SCS (Subcarrier Spacing) is supported.

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

[0100] According to the above description, the active time (or on-duration) in DRX can be defined by when the 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 mentioned above, some of the parameters may not be used in sidelink DRX, or other parameters may be considered. This may vary depending on the sidelink transmission method (broadcast, unicast, or groupcast). Furthermore, the method for configuring the parameter information is not limited to a specific method. This information may be pre-configured, or in the case of unicast, it may be configured via PC5-RRC or sidelink MAC-CE.

[0102] In the following embodiments, a method for Mode 2 sensing and resource selection in a UE when DRX is operated in the sidelink (FIGS. 11a-11d) is provided. A method for cooperation between UEs 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 the sidelink is provided.

[0104] Specifically, FIG. 12 illustrates four terminals transmitting and receiving sidelink data according to an embodiment of the present disclosure. In FIG. 12, UE1 is a terminal attempting to transmit sidelink data, i.e., PSSCH, to UE2, and UE2 may be a terminal performing sidelink DRX. As described above, if UE1 transmits sidelink data to UE2 during the sidelink DRX inactive time (i.e., UE2 may not decode control information and data information during this time), UE2 may not be able to receive the data. Therefore, as shown in 1201, a peer terminal transmitting sidelink data as a terminal performing DRX needs to select resources by performing Mode 2 sensing so that the receiving terminal can receive the transmitted data. For details of this method, please refer to the second and third embodiments below. UE1 can then select the resources determined through the resource selection operation considered in 1201 and transmit PSCCH / PSSCH 1202 to UE2. Next, in FIG. 12, UE2 is a terminal performing sidelink DRX, and the sensing operation during the inactive time and active time of sidelink DRX may or may not be the same. For details on the case where the sensing operation is the same, see FIGS. 7 to 10. Alternatively, sensing may be performed in a different manner as in 1203. This is because DRX is an operation to reduce power consumption of the terminal. For details on this, see the fourth embodiment below. Referring to FIG. 12, UE3 is a terminal that intends to transmit sidelink data, i.e., PSSCH transmission 1205, with UE4. UE4 may not perform sidelink DRX. In this case, UE2 can receive and decode the PSCCH 1204 transmitted by UE3 during the sensing period, regardless of DRX, and perform the sensing operation.

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

[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 transmitting sidelink data from a UE performing DRX determines a resource selection window 1300, a portion of the time region of the resource selection window may correspond to the inactive time 1301 of the UE performing DRX, and another portion 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 during the DRX inactive time. Therefore, if a peer UE transmitting sidelink data from a UE performing DRX transmits sidelink data during 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 data.

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

[0109] When a peer UE transmits sidelink data via a UE that performs DRX, the following resource selection methods are possible: Please note that the following methods are for illustrative purposes only and the resource selection method in the present invention is not limited to the following methods.

[0110] *Method 1: When the UE selects a set of candidate resources through Mode 2 operation and reports it to the UE's upper layer, 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 resources included in the set may be included in the time interval corresponding to the DRX active time of the RX terminal, and 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 UE from the physical layer of the UE, the upper layer of the UE can 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 can be selected. If the initial transmission resource and the retransmission resource are selected, the resource located earlier in time among the randomly selected resources can be the initial transmission resource, and the resource located later in time can be the retransmission resource. When Method 1 is used, it is possible to ensure that the transmission resource is always selected during the DRX active time of the RX UE, thereby preventing sidelink data transmitted by the TX UE from being transmitted during the DRX inactive time of the RX UE. However, if the area corresponding to 1302 in FIG. 13 is small, it may be difficult to ensure a sufficient number of candidate resources included in the set of candidate resources. In general, if the number of candidate resources included in the set of candidate resources is sufficiently guaranteed, the probability of collision with resources selected by other UEs can be reduced when the set of candidate resources is reported to the upper layer of the UE and random selection is performed. In contrast, when Method 2 is used, it is not guaranteed that transmission resources are always selected during the DRX active time of the RX UE, which may result in the sidelink data transmitted by the TX UE being transmitted during the DRX inactive time of the RX UE. However, since candidate resources can be selected from the area 1301 even when the area corresponding to 1302 in FIG. 13 is small, there may be no problem in ensuring a sufficient number of candidate resources included in the candidate resource set.

[0113] When the above-described method 2 is used, in order to compensate for the drawbacks of method 2, 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 taking DRX into consideration when method 2 is used, please refer to the third embodiment.

[0114] In addition, sidelink retransmission methods can be divided into a HARQ feedback-based retransmission method and a blind retransmission method. The HARQ feedback-based retransmission method is a method in which retransmission is performed if HARQ feedback is received after the initial transmission and a NACK is received, and no retransmission is performed otherwise. 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. In this case, the terminal can perform blind retransmission. Blind retransmission is a method in which, when a terminal selects a retransmission resource, it must perform repeated transmissions on the selected resource. Therefore, when performing blind retransmission, when a peer terminal is a terminal performing DRX and transmitting sidelink data, it is necessary to ensure that not only the initial transmission but also the retransmission is transmitted in a time interval 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: When unicast or groupcast transmission is applicable

[0117] *Condition 3: Unicast transmission

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

[0119] Condition 2 is due to the fact that HARQ feedback-based retransmission is only supported in unicast or groupcast transmission. Condition 3 is due to the purpose of further restricting the environment in which Method 2 is applied. Condition 4 can 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] 14, if one or more of the conditions presented in 1400 are satisfied, the UE may proceed to 1401 and apply Method 2. Alternatively, if at least one condition is not satisfied in 1400, the UE may proceed to 1402 and 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, some resources included in the set may not be included in the time interval corresponding to the DRX active time of the SL DRX of the RX UE, or all resources may be included in the time interval corresponding to the DRX active time of the SL DRX of the RX UE. Therefore, Method 1 may also 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 the set of candidate resources (SA) through the Mode 2 procedure in the physical layer, the candidate resources are selected from all candidates (M) within the resource selection window as shown in Figure 7. total ) can be determined within M total DeS A The process of selecting S is based on the sensing results. A ≧X·M total Here, X is the number of candidate resources that correspond to S. A The factor for determining whether to include X can be selected from the values ​​{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 A ≧X·M total This can be ensured as mentioned above. AIf 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 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 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 candidate resources included in M. total can be a candidate resource to be included in

[0125] If DRX is taken into account and Method 1 is used, S A Since all resources included within 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. total In the case of periodic resource reservation with partial sensing, only Y slots included in the DRX active time within the resource selection window [n+T1, n+T2] can be candidate resources included in M. total In the case of aperiodic resource reservation with partial sensing, only Y' slots included in the DRX active time within 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 totalYou will be able 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, referring to FIG. 13, the time period corresponding to 1302 may not be sufficiently secured, and the S A This is because many resource candidates may be excluded in the time period corresponding to 1302 during the selection process. Therefore, it is necessary to define the Mode 2 procedure to prevent this problem from occurring. In other words, when Method 2 is used, the S A It is necessary to ensure that a certain amount of resources included in the time interval 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 resource selection window 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 included in the region, and perform the Mode 2 procedure in the region to obtain S A ≧X·M total Only if it is not possible to satisfy the above condition, S is selected in the time region corresponding to the DRX inactive time of the RX terminal within the resource selection window. A By additionally selecting candidate resources included in S A ≧X·M total can be satisfied.

[0129] More specifically, in the case of 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 time region M 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) In this case, M total =M total (1)+M total (2) is satisfied. In the physical layer, the terminal acquires S through two Mode 2 procedures. A (1)≧X M total (1) and S A (2)≧X·M total(2) can be selected. Here, X is the number of candidate resources that can be selected from S. A It is a parameter provided by the upper layer of the terminal as a factor to determine whether to include it in S. A (1) is a resource candidate selected in the time domain corresponding to the DRX active time, and 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 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. A It 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 it is a factor that determines 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 in the physical layer as described above 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 explained in more detail below. total When the DRX active time of the RX terminal is determined, the UE first selects S in the time domain 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 mentioned above, the result of the sensing process, S 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 belonging to the 1302 area, no matter how much the RSRP threshold is lowered, the S A ≧X·M total Therefore, in alternative 2, only in such a case, S is performed in the time domain corresponding to the DRX inactive time of the RX terminal within the resource selection window. A By additionally selecting candidate resources included in S A ≧X·M total This is a way to satisfy the above.

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

[0134] The sensing operation of a typical UE has been described with reference to Figure 7 (full sensing), Figure 8 (partial sensing for periodic transmission), and Figure 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 can 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 with reference to 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 intending 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, a terminal other than the transmitting terminal may provide resource allocation-related information to the transmitting terminal. Here, the provision of resource allocation-related information by a terminal other than the transmitting terminal to the transmitting terminal can be referred to as inter-terminal cooperation. In this case, 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 suitable (preferable) or unsuitable (unpreferable) time-frequency resource allocation set information for transmission from UE-A to UE-B according to the inter-terminal cooperation method 1 described with reference to FIG. 10 are 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 unsuitable (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 cooperation between terminals, UE-A provides UE-B with cooperation information between terminals.

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

[0142] In the case of transmission method 2, the specific condition may be a periodically set time. UE-A may then 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 for 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 can be considered as a method for UE-B to request cooperation between UEs 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 through 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, it is a newly defined 2 nd This can be done through the SCI format. nd SCI format 2 nd It is called SCI format X. 2 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 uses the information provided in Table 1 by UE-A in two ways. nd It may be provided together with a request for cooperation between terminals via SCI format X.

[0148] [Table 1]

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

[0150] Alternatively, the following two methods can be considered as a method for UE-A to provide cooperation information between terminals to UE-B in transmission method 1, 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: If the amount of cooperation information between UEs is greater than a certain threshold, the cooperation information between UEs is signaled through MAC CE. Otherwise, nd Cooperation information between terminals is signaled through the SCI.

[0153] 2. nd When SCI is used, it is a 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, nd SCI format X and different new 2 nd It can also be defined as SCI format. nd Same as SCI format2 nd If determined to be SCI format X, the restricted 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, it is later changed to another 2 bits. nd This has the advantage of leaving 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 can vary depending on whether it is used in transmission method 1-1-2 or transmission method 1-2-2. First, the 2 for cooperation information signaling between UEs according to transmission method 1-2-2 nd The SCI format may include the following bit fields in addition to those listed in Table 1:

[0154] [Table 2]

[0155] In Table 2, the Identifier for SCI Format may be a field that distinguishes whether the 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 information is not limited to a specific value.

[0156] It should be noted that according to the transmission methods 1-1-1, 1-1-2, 1-1-3, and 1-2-1 and 1-2-2 presented above, the sidelink terminal can indicate the information in different ways when requesting cooperation between terminals and when providing cooperation information between terminals. For example, when transmission method 1 is used as the sidelink transmission method, if transmission methods 1-1-2 and 1-2-1 are considered, the terminal may indicate the information using other methods depending on 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 a set of information on time-frequency resource allocation suitable (preferable) or unsuitable (unpreferable) for transmission. In addition, as described in the fifth embodiment, the following transmission method 1 can be considered.

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

[0159] In this embodiment, a condition is proposed in which UE-A requests cooperation information between UEs from UE-B in 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 presented options. Specifically, if any one of the options other than Option 9 is a necessary and sufficient condition for UE-A to request UE-B cooperation information, the conditions for requesting UE-B cooperation may be very restrictive. Therefore, the conditions for UE-A to request UE-B cooperation information may be determined by the combination of the presented options. For example, Option 1 may be a necessary condition for UE-A to request UE-B cooperation information. In addition, other options may be determined by the UE implementation.

[0162] The seventh embodiment proposes 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. Also, the seventh embodiment proposes a method utilizing the method proposed in the third embodiment and an additional method for selecting a set of candidate resources taking DRX into consideration.

[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 UE's upper layer, 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 terminal's upper layer, some resources included in the set may be included in the time interval corresponding to the DRX active time of the RX terminal, and 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 non-zero reservation interval (or periodicity) P rsvp_TX SCI(1 st There is a method to periodically reserve transmission resources by instructing it with the SCI. 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 SCI) through P 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 the DRX-related parameters as shown in FIG. 11 in consideration of the periodic transmission of the TX terminal. Therefore, the TX terminal selects transmission resources 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 by the UE upper layer through sensing in the physical layer is included in a time interval 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. Therefore, method 1 or method 2 of the second embodiment may not be required. 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 terminal operations 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 through the SCI can be applied to the case where the RX terminal considers it 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 UE can move to 1801 and report the selected candidate resources to the UE 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 UE may not adjust the candidate resources to be included in the DRX active time during the process of selecting candidate resources. On the other hand, if the condition is not satisfied in 1800, in other words, the TX UE performs aperiodic transmission (P rsvp_TX =0), the UE may proceed to 1802 and report the selected candidate resources to the upper layer of the UE using the modified Mode 2 method. Here, the modified Mode 2 method differs from the existing Mode 2 method in that it selects candidate resources taking into account the sidelink DRX configuration. For example, Method 1 or Method 2 of the second embodiment may 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. Furthermore, the terminal operation 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 within 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. When performing periodic resource reservation with partial sensing as shown in FIG. 8 (P rsvp_TX ≠ 0), N candidate resources (N slots) in Y slots within the resource selection window [n+T1, n+T2] can be restricted to be in the DRX active time. rsvp_TX ≠0) N candidate resources (N slots) in Y' slots within the resource selection window [n+T1, n+T2] can be restricted to be in the DRX active time. totalIt should be noted that N can be the total number of candidate resources before selecting candidate resources using the sensing result. In the above alternative, the value of N can 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 can be limited to resources located earlier in time. In addition, the N candidate resources can be selected by full sensing. total , and with partial sensing, N=Y or N=Y'.

[0173] In the second alternative, the set of candidate resources (S A ) and report it to the upper layer of the terminal. A This is a method of restricting the candidate resources included in S so that at least K candidate resources (K slots) are 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 that correspond to the DRX active time among the candidate resources included in N. total This parameter is provided by the upper layer of the terminal as a factor indicating how many candidate resources to select from. 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 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 terminal's upper layer and random selection is performed. In the second alternative, X·N total The selection and reporting of resource candidates that fall under this category is 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 the upper layer of the terminal.

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

[0175] Specifically, FIG. 16 is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present invention. As shown in FIG. 16, the terminal according to 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 transmitter 1604 may be collectively referred to as a transceiver in an embodiment of the present invention. The transceiver can transmit and receive signals to and from a base station. The signals may include control information and data. To this end, the transceiver can 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 and down-converts the frequency of a received signal. In addition, the transceiver can receive signals through a wireless channel and output them to the terminal processor 1602, and transmit the signals output from the terminal processor 1602 through a wireless channel. The terminal processor 1602 can control a series of processes so that the terminal operates according to the above-described embodiment of the present invention.

[0176] FIG. 17 is a block diagram showing the 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 and down-converts the frequency of a received signal. In addition, the transceiver may receive signals through a wireless channel and output them to the base station processor 1703, and transmit the signals 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-described embodiment of the present invention.

[0177] Meanwhile, the embodiments of the present invention disclosed in this specification and drawings are merely specific examples to easily explain the technical content of the present invention and to facilitate understanding of the present invention, and are not intended to limit the scope of the present invention. In other words, it is obvious to those skilled in the art that other modifications can be made based on the technical ideas of the present invention. Furthermore, the above-mentioned embodiments can be combined with each other as needed. For example, all 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 above 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, not 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. 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 to a second UE; receiving a second SCI from the second UE, the second SCI providing cooperation information between the terminals; The first SCI includes a field indicating that the first SCI is used to request cooperation information between the terminals; The second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals; A method, wherein the payload sizes of the first SCI including a field indicating that the first SCI is used to request cooperation information between the terminals and the second SCI including a field indicating that the second SCI is used to provide cooperation information between the terminals are identical.

2. The method of claim 1, wherein the first SCI and the second SCI correspond to the same SCI format, and the SCI format is a 2nd-stage SCI transmitted over a physical sidelink shared channel (PSSCH).

3. A field indicating that the first SCI is used to request cooperation information between the terminals corresponds to a first value; The method of claim 1 , wherein a field indicating that the second SCI is used to provide cooperation information between the terminals corresponds to a second value.

4. The bit size of a field indicating that the first SCI is used to request cooperation information between the terminals is 1 bit; The method of claim 1, wherein a bit size of a field indicating that the second SCI is used to provide cooperation information between the terminals 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; transmitting a second SCI to the first UE, the second SCI providing cooperation information between the terminals; The first SCI includes a field indicating that the first SCI is used to request cooperation information between the terminals; The second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals; A method, wherein the payload sizes of the first SCI including a field indicating that the first SCI is used to request cooperation information between the terminals and the second SCI including a field indicating that the second SCI is used to provide cooperation information between the terminals are identical.

6. The method of claim 5, wherein the first SCI and the second SCI correspond to the same SCI format, and the SCI format is a 2nd-stage SCI transmitted over a physical sidelink shared channel (PSSCH).

7. A field indicating that the first SCI is used to request cooperation information between the terminals corresponds to a first value; The method of claim 5, wherein a field indicating that the second SCI is used to provide cooperation information between the terminals corresponds to a second value.

8. The bit size of a field indicating that the first SCI is used to request cooperation information between the terminals is 1 bit; The method of claim 5, wherein a bit size of a field indicating that the second SCI is used to provide cooperation information between the terminals is 1 bit.

9. A first user equipment (UE) in a communication system, a transmitter / receiver; 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; The second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals; A first UE, wherein the payload sizes of the first SCI including a field indicating that the first SCI is used to request cooperation information between the terminals and the second SCI including a field indicating that the second SCI is used to provide cooperation information between the terminals are the same.

10. The first UE of claim 9, wherein the first SCI and the second SCI correspond to the same SCI format, and the SCI format is a second-stage SCI transmitted over a physical sidelink shared channel (PSSCH).

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

12. The bit size of a field indicating that the first SCI is used to request cooperation information between the terminals is 1 bit; The first UE of claim 9, wherein a bit size of a field indicating that the second SCI is used to provide cooperation information between the terminals is 1 bit.

13. A second UE (user equipment) in a communication system, a transmitter / receiver; a controller configured to receive, from a first UE, a first sidelink control information (SCI) requesting inter-UE coordination information, and to transmit, to the first UE, a second sidelink control information (SCI) providing the inter-UE coordination information; The first SCI includes a field indicating that the first SCI is used to request cooperation information between the terminals; The second SCI includes a field indicating that the second SCI is used to provide cooperation information between the terminals; A second UE, wherein the payload sizes of the first SCI including a field indicating that the first SCI is used to request cooperation information between the terminals and the second SCI including a field indicating that the second SCI is used to provide cooperation information between the terminals are the same.

14. The second UE of claim 13, wherein the first SCI and the second SCI correspond to the same SCI format, and the SCI format is a second-stage SCI transmitted over a physical sidelink shared channel (PSSCH).

15. The method of claim 14, wherein a field indicating that the first SCI is used to request cooperation information between the terminals corresponds to a first value; The second UE of claim 13, wherein a field indicating that the second SCI is used to provide cooperation information between the terminals corresponds to a second value.

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