Method and apparatus for allocating resources through cooperation between terminals in a V2X system

Abstract

The present disclosure relates to a communication technique and system thereof 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, smart retail, security and safety services, etc.) based on 5G communication technology and IoT-related technology. A method of a first terminal of a communication system according to an embodiment of the present disclosure may include sharing information on a resource pool with a second terminal, receiving a request for resource allocation information from the second terminal, and transmitting, from the second terminal, resource allocation information indicating at least one resource related to the resource pool shared with the second terminal.

Description

[Technical Field]

[0001] The present invention relates to a wireless mobile communication system, and more particularly to a method and apparatus for performing resource allocation through cooperation between terminals in a process in which a vehicle terminal supporting V2X (vehicle-to-everything) transmits and receives information with other vehicle terminals and pedestrian mobile terminals using a sidelink. [Background technology]

[0002] Efforts are underway to develop improved 5G or pre-5G communication systems to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems. For this reason, 5G or pre-5G communication systems are referred to as beyond-4G network (Beyond 4G Network) or post-LTE (Post-LTE) 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, technological developments are being made in the 5G communication system, such as advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D communication), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and receive interference cancellation.In addition, 5G systems are being developed with advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), 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 is evolving from a human-centered network where humans generate and consume information to an IoT (Internet of Things) network where information is exchanged and processed among distributed components such as objects. IoE (Internet of Everything) technology, which combines big data processing technology through connections to cloud servers and other devices, is also emerging. To realize the IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. In recent years, research has focused on sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) for connecting things. The IoT environment provides intelligent IT (Internet Technology) services that collect and analyze data generated by connected objects and create new value in people's lives. Through the convergence and integration of existing IT (information technology) and various industries, the IoT is being 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 to IoT networks. For example, 5G communication technologies such as sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) can be realized using techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN) as the aforementioned big data processing technology can also be seen as an example of the convergence of 5G and IoT technologies. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention relates to a wireless communication system, and more particularly to a method and apparatus for allocating transmission resources through cooperation between UEs in a process in which a vehicular UE supporting V2X exchanges information with other vehicular UEs and pedestrian mobile UEs using a sidelink. Specifically, the present invention relates to a method for exchanging information for cooperation between UEs, a method for allocating sidelink transmission resources through the exchange, and operations of a base station and UEs therefor. [Means for solving the problem]

[0006] A method for a first terminal in a communication system according to one embodiment of the present disclosure to solve the above problems may include a step of sharing information regarding a resource pool with a second terminal, a step of receiving a request for resource allocation information from the second terminal, and a step of transmitting resource allocation information from the second terminal indicating at least one resource related to the resource pool shared with the second terminal.

[0007] According to one embodiment, the method further includes, when a plurality of resource pools are shared with the second terminal, transmitting information to the second terminal for indicating at least one of the plurality of resource pools, and at least one of the plurality of resource pools can be determined based on a CBR (channel busy ratio).

[0008] According to one embodiment, the method further includes receiving at least one of priority information, a remaining packet delay budget, a buffer status report, whether to grant HARQ feedback, and information regarding the number of consecutive subchannels on a frequency from the second terminal, and the resource allocation information can be determined based on the information received from the second terminal.

[0009] According to an embodiment, the resource allocation information may include location information of initial resources and location information of retransmission resources for at least one transmission block.

[0010] A method for a second terminal in a communication system according to one embodiment of the present disclosure may include a step of sharing information regarding a resource pool with a first terminal, a step of transmitting a request for resource allocation information from the first terminal, and a step of receiving resource allocation information from the first terminal indicating at least one resource related to the resource pool shared with the first terminal.

[0011] A first terminal of a communication system according to one embodiment of the present disclosure may include a transceiver unit and a control unit configured to share information regarding a resource pool with a second terminal, receive a request for resource allocation information from the second terminal, and transmit resource allocation information indicating at least one resource related to the resource pool shared with the second terminal to the second terminal.

[0012] A second terminal of a communication system according to one embodiment of the present disclosure may include a transceiver unit and a control unit configured to share information regarding a resource pool with a first terminal, transmit a request for resource allocation information from the first terminal, and receive resource allocation information from the first terminal indicating at least one resource related to the resource pool shared with the first terminal. [Effects of the Invention]

[0013] The present invention proposes a procedure for a terminal to perform resource allocation in sidelink communication. The proposed method can improve resource allocation performance and can be effectively used to minimize power consumption of the terminal. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating a system according to an embodiment of the present disclosure. [Figure 2] 1 is a diagram illustrating a V2X communication method performed via a sidelink according to an embodiment of the present disclosure. [Figure 3] 1 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 of the present disclosure. [Figure 4] 1 is a diagram illustrating a method for allocating transmission resources in a sidelink by a base station according to an embodiment of the present disclosure. [Figure 5] 1 is a diagram illustrating a method for a UE directly allocating sidelink transmission resources through sensing in a sidelink according to an embodiment of the present disclosure. [Figure 6] 1 is a diagram illustrating a mapping structure of physical channels mapped to one slot in a sidelink according to an embodiment of the present disclosure. [Figure 7]1 is a diagram illustrating a scenario in which terminals cooperate with each other to receive resource allocation-related information from other terminals according to an embodiment of the present disclosure. [Figure 8] 1 is a diagram for defining a sensing window and a resource selection window required for UE-A to perform resource (re)allocation and reevaluation for UE-B's resource allocation according to one embodiment of the present disclosure. [Figure 9] FIG. 10 is an illustrative diagram showing an overall flowchart of cooperation between terminals in sidelink communication according to one embodiment of the present disclosure. [Figure 10] FIG. 2 is a block diagram illustrating a configuration of a terminal according to an embodiment of the present disclosure. [Figure 11] FIG. 1 is a block diagram illustrating a configuration of a base station according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0016] In describing the embodiments, technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted in order to clarify and more clearly convey the gist of the present disclosure by omitting unnecessary details.

[0017] For the same reasons, some components in the accompanying drawings are exaggerated, omitted, or illustrated schematically, and the size of each component does not necessarily reflect the actual size. The same or corresponding components in each drawing are designated by the same reference numerals.

[0018] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the following detailed description of the embodiments along with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, and may be embodied in various different forms. The embodiments are provided to complete the disclosure and to fully convey the scope of the disclosure to those skilled in the art to which the disclosure pertains, and the present disclosure is defined only by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

[0019] It will be understood that the combination of each block of the process flowchart and the flowchart figures is implemented by computer program instructions. These computer program instructions can be loaded onto a processor in a general-purpose computer, 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 the functions in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory can produce an article of manufacture 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, and the instructions that cause the computer or other programmable data processing device to provide the steps for performing the functions described in the flowchart blocks.

[0020] 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.

[0021] The term "module" used in this embodiment refers to software or hardware components such as FPGAs or ASICs, and the "module" may perform any 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, for example, the "module" may include 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 functionality 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 CPUs within a device or a secure multimedia card. In some embodiments, the "module" may include one or more processors.

[0022] In describing the embodiments of the present disclosure in detail, the main focus will be on the New RAN (NR), a radio access network on the 5G mobile communication standard disclosed by 3GPP (registered trademark) (3rd generation partnership project long term evolution), a mobile communication standardization organization, and the packet core (5G System, also known as 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 minor modifications within the scope of the present disclosure without significantly departing from the scope of the present disclosure, and this would be possible at the discretion of a person skilled in the technical field of the present disclosure.

[0023] 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 provides the ability to analyze and provide 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.

[0024] 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 to the terms and names and may be similarly applied to systems according to other standards.

[0025] 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 convenience of explanation, and are not limited to the terms used in this disclosure, and other terms for designating objects having equivalent technical meanings may be used.

[0026] 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 utilize resources in ultra-high frequency (mmWave) bands (e.g., the 28 GHz frequency band). To mitigate path loss and increase transmission distance in ultra-high frequency bands, technologies such as beamforming, massive multiple-input multiple-output (MMWave), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antennas are being discussed for the 5G communication system. Unlike LTE, the 5G communication system allocates various subcarrier spacings, including 15 kHz, such as 30 kHz, 60 kHz, and 120 kHz, and uses polar coding for the physical control channel and low density parity check (LDPC) for the physical data channel. Additionally, both DFT-S-OFDM and CP-OFDM are used as waveforms for uplink transmission. While LTE allocates Hybrid ARQ (HARQ) retransmissions on a Transport Block (TB) basis, 5G can additionally allocate HARQ retransmissions based on Code Block Groups (CBGs), which are groups of multiple Code Blocks (CBs).

[0027] In addition, to improve the system's network, technologies being developed for the 5G communication system include advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D communication), wireless backhaul, vehicle-to-everything (V2X) networks, cooperative communication, coordinated multi-points (CoMP), and interference cancellation.

[0028] Meanwhile, the Internet is evolving from a human-centered network where humans generate and consume information to an IoT (Internet of Things) network where information is exchanged and processed among distributed components such as objects. IoE (Internet of Everything) technology, which combines big data processing technology through connections to cloud servers and other devices, is also emerging. To realize the IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. In recent years, research has focused on sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) for connecting things. 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.

[0029] As a result, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) can be implemented in 5G communication technologies using techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN) as the aforementioned big data processing technology can also be seen as an example of the convergence of 5G and IoT technologies. 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. Various services to be provided by 5G communication systems are being researched, and one of these is a service that meets the requirements of low latency and high reliability.

[0030] In the case of vehicle communications, the NR V2X system supports unicast, groupcast (or multicast), and broadcast communications between terminals. Unlike LTE V2X, which aims to transmit and receive basic safety information required for vehicle operation on roads, NR V2X aims to provide more advanced services such as platooning, advanced driving, extended sensors, and remote driving. The NR V2X system also supports a method in which terminals directly sense and allocate sidelink transmission resources, taking into account both periodic and aperiodic traffic. Resource allocation-related information can be provided by other terminals. Receiving resource allocation-related information from other terminals not only improves resource allocation performance but also reduces terminal power consumption. For example, a base station can receive channel congestion information, such as a channel busy ratio (CBR), from a terminal located within its coverage. Therefore, when a terminal is located within the base station's coverage, the base station can better configure a resource pool, defined as a set of resources on time and frequency used for sidelink transmission and reception. Therefore, resource allocation performance can be improved when resource allocation-related information is provided by a terminal within the base station's coverage, rather than when a terminal located outside the base station's coverage is allocated resources from a pre-configured resource pool. In another example, when supporting advanced services such as group driving in the sidelink, a scenario can be considered in which a leader node of a group connected in group driving provides resource allocation-related information for the purpose of controlling one specific node or simultaneously controlling a group consisting of multiple specific nodes.In this case, rather than each node in the group allocating resources individually, the leader node can better grasp the group status and provide resource allocation-related information, which can be expected to improve the performance of group operation. Furthermore, since a terminal consumes a lot of power when performing sensing to select sidelink transmission resources, if other terminals allocate resources instead, the terminal's power consumption can be minimized. In particular, in the case of a pedestrian mobile terminal, a method and procedure for allocating transmission resources while minimizing the terminal's power consumption may be required. Therefore, terminal and base station operations to provide such a solution must be defined. However, there has been no discussion on this topic. Therefore, the present invention proposes a method for cooperation between terminals so that resource allocation-related information can be provided from other terminals.

[0031] The embodiments of the present specification are proposed to support the above-mentioned scenarios, and particularly aim to provide a method and apparatus for a procedure (Mode 2) in which a terminal performs sensing and resource allocation in a sidelink. Furthermore, a Mode 2 method is proposed to minimize power consumption of the terminal.

[0032] FIG. 1 is a diagram illustrating a system according to an embodiment of the present disclosure.

[0033] Figure 1(a) shows an example where all V2X terminals (UE-1 and UE-2) are located within the coverage of the base station (In-Coverage, IC). All V2X terminals can receive data and control information from the base station via downlink (DL) or transmit data and control information to the base station via 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 sidelink (SL).

[0034] FIG. 1(b) illustrates an example in which one V2X device, 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, FIG. 1(b) illustrates an example of partial coverage (PC) in which a V2X device, UE-2, is located outside the coverage of the base station. The V2X device, 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 from the base station via an uplink. The V2X device, 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 from the base station via an uplink. The V2X device, UE-2, can transmit / receive data and control information for V2X communication with the V2X device, UE-1, via a sidelink.

[0035] Figure 1(c) shows an example in which 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 from the base station via uplink. The V2X terminals (UE-1, UE-2) can transmit / receive data and control information for V2X communication via sidelink.

[0036] (d) of FIG. 1 illustrates an example scenario in which V2X communication is performed between V2X terminals (UE-1, UE-2) located in different cells. Specifically, (d) of FIG. 1 illustrates a case in which the V2X terminals (UE-1, UE-2) are connected to different base stations (RRC connected state) or camping (RRC disconnected state, i.e., RRC idle state). 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 the corresponding information may be signaled, and an additional method for interpreting SIB information transmitted from different cells may be required.

[0037] For convenience of explanation, FIG. 1 illustrates a V2X system configured with two V2X terminals (UE-1 and UE-2). However, the present disclosure is not limited to this configuration and communication between more V2X terminals is also possible. 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 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 handset (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.

[0038] 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.

[0039] FIG. 2 is a diagram illustrating a V2X communication method performed via a sidelink according to one embodiment of the present disclosure.

[0040] Referring to FIG. 2(a), UE-1 (201, e.g., TX terminal) and UE-2 (202, e.g., RX terminal) can communicate one-to-one, which can be called unicast communication.

[0041] Referring to Figure 2(b), a TX terminal and an RX terminal can communicate one-to-one with each other, 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 different groups can be performed via unicast, groupcast, or broadcast communication. Figure 2(b) shows the formation of two groups (Group A and Group B), but this is not limited thereto.

[0042] Meanwhile, although not shown in Figure 2, 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 via a sidelink. For example, in Figure 2(b), if UE-1 (211) is assumed to be a transmitting terminal for broadcast, all terminals (UE-2 (212), UE-3 (213), UE-4 (214), UE-5 (215), UE-6 (216), and UE-7 (217)) can receive the data and control information transmitted by UE-1 (211).

[0043] Unlike LTE V2X, NR V2X can support a mode in which a vehicle terminal transmits data to only one specific node via unicast and a mode in which a vehicle terminal transmits data to a number of specific nodes via groupcast. For example, such unicast and groupcast technologies can be useful in a service scenario such as platooning, in which two or more vehicles are connected to one network and move in a platoon. Specifically, unicast communication may be required for the leader node of a group connected in platooning to control one specific node, and groupcast communication may be required for the purpose of simultaneously controlling a group consisting of a number of specific nodes.

[0044] 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 of the present disclosure.

[0045] In the resource pool, the resource allocation unit on the time axis can be a slot, and the resource allocation unit on the frequency axis can be a sub-channel consisting of one or more physical resource blocks (PRBs).

[0046] When a resource pool is allocated in time and frequency (310), the shaded area indicates an area set as a resource pool in time and frequency. Although the present disclosure describes an example in which the resource pool is allocated discontinuously in time, the resource pool may also be allocated contiguously in time. Also, although the present disclosure describes an example in which the resource pool is allocated contiguously in frequency, a method in which the resource pool is allocated discontinuously in frequency is not excluded.

[0047] FIG. 3 illustrates a case where a resource pool is allocated discontinuously in time (320). FIG. 3 also illustrates a case where the granularity of resource allocation in time is a slot. Specifically, one slot consisting of a plurality of OFDM symbols can be the basic unit of resource allocation in time. In this case, all of the OFDM symbols constituting the slot can be used for sidelink transmission, or some of the OFDM symbols constituting the slot can be used for sidelink transmission. For example, some of the slots can be used for downlink / uplink used in the Uu interface between the base station and the terminal. Referring to FIG. 3, the shaded slots indicate slots included in the resource pool in time, and the slots allocated in the resource pool can be pre-configured by time resource pool information. For example, the time resource pool information can be indicated in a bitmap via a SIB.

[0048] 3, physical slots 320 belonging to resource pools that are not contiguous in time can be mapped to logical slots 321. In general, a set of slots belonging to a physical sidelink shared channel (PSSCH) resource pool can be denoted by (t0, t1, ..., t1, ..., tTmax).

[0049] Referring to FIG. 3, a case where the resource pool is allocated contiguously on the frequency (330) is shown.

[0050] Resource allocation on the frequency axis can be performed in units of sub-channels 331. A sub-channel 331 can be defined as a resource allocation unit on the frequency composed of one or more RBs. That is, a sub-channel 331 can be defined as an integer multiple of the RB. Referring to FIG. 3, a sub-channel 331 can be composed of five consecutive PRBs, and the sub-channel size (sizeSubchannel) may be the size of five consecutive PRBs. However, the content shown in the drawing is only an example of the present invention, and the size of the sub-channel can 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 331 can be a basic unit of resource allocation for a PSSCH.

[0051] The startRB-Subchannel 332 may indicate the start position of a subchannel 331 on the frequency axis in a resource pool. When resource allocation on the frequency axis is in units of subchannels 331, resources on the frequency axis may be allocated through configuration information such as the RB index (startRB-Subchannel, 332) at which the subchannel 331 starts, information on how many RBs the subchannel 331 consists of (sizeSubchannel), and the total number of subchannels 331 (numSubchannel). At this time, information on the startRB-Subchannel, sizeSubchannel, and numSubchannel may be (pre-)configured in resource pool information on the frequency axis. For example, the frequency resource pool information may be configured and indicated via a SIB.

[0052] FIG. 4 is a diagram illustrating a method for a base station to allocate transmission resources in a sidelink according to one embodiment of the present disclosure.

[0053] The method by which the base station allocates transmission resources for the sidelink is referred to as Mode 1 below. Mode 1 may be scheduled resource allocation. Mode 1 can refer to a method in which the base station allocates resources used for sidelink transmission to an RRC-connected terminal using dedicated scheduling. Mode 1 allows the base station to manage sidelink resources, which is effective for interference management and resource pool management.

[0054] 4, a transmitting terminal 401 and a receiving terminal 402 camping on 405 can receive a sidelink system information block (SL-SIB) from a base station 403 (410). Here, the receiving terminal 402 refers to a terminal that receives data transmitted by the transmitting terminal 401. 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.

[0055] 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 via 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 via the sidelink even when the Uu-RRC connection procedure 420 between the base station 403 and the receiving terminal 402 is not performed.

[0056] The transmitting terminal 401 can request transmission resources (430) from the base station 403 to enable V2X communication with the receiving terminal 402. 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 MAC 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). In addition, the transmitting terminal 401 can request sidelink resources via a scheduling request (SR) bit transmitted over the uplink physical control channel.

[0057] 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.

[0058] First, in the case of the dynamic grant scheme, the base station can allocate resources for TB transmission via downlink control information (DCI). The sidelink scheduling information included in the DCI can include parameters related to the transmission time points and frequency allocation location information fields of the initial transmission and retransmission. The DCI for the dynamic grant scheme can include a cyclic redundancy check (CRC) scrambled with the SL-V-RNTI to indicate that it is a dynamic grant scheme.

[0059] 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 via Uu-RRC. In this case, the base station can allocate resources for one TB via DCI. The sidelink scheduling information for one TB included in the DCI may include information on the transmission time and frequency allocation location of the initial transmission and retransmission resources, as well as related parameters. 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 the SPS interval set via Uu-RRC. The DCI for the configured grant method may include a CRC scrambled with the SL-SPS-V-RNTI to indicate the 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 via DCI.

[0060] Therefore, in the case of Mode 1, the base station 403 can instruct the transmitting terminal 401 to schedule sidelink communication with the receiving terminal 402 by transmitting DCI over the PDCCH (440).

[0061] In the case of broadcast transmission, the transmitting terminal 401 broadcasts SCI(1) to the receiving terminal 402 via the PSCCH without RRC configuration 415 for the side link. st In addition, the transmitting terminal 401 can broadcast data to the receiving terminal 402 via the PSSCH (480). In the case of broadcast transmission, the SCI transmission (2 ndstage SCI, 470) may not be performed.

[0062] Alternatively, 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, distinguished from Uu-RRC. In the case of groupcast, PC5-RRC 415 can also 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 before SL-SIB transmission 410 or before SCI transmission. If an RRC connection between terminals is required, a sidelink PC5-RRC connection is performed and the transmitting terminal 401 sends an SCI(1) to the receiving terminal 402 via the PSCCH. st The SCI (stage) can be transmitted by unicast or groupcast (460). In this case, the groupcast transmission of the SCI can be interpreted as a group SCI. Also, the transmitting terminal 401 transmits the SCI (stage) to the receiving terminal 402 via the PSSCH. nd The stage can be transmitted by unicast or groupcast (470). 1st The stage SCI contains information related to resource allocation and nd Other control information can be included in the stage SCI. In addition, the transmitting terminal 401 can transmit data to the receiving terminal 402 via the PSSCH by unicast or groupcast (480).

[0063] FIG. 5 illustrates a method for directly allocating sidelink transmission resources via sensing by a terminal in a sidelink according to an embodiment of the present disclosure. Hereinafter, the method for directly allocating sidelink transmission resources via sensing by a terminal in a sidelink is referred to as Mode 2. Mode 2 may also be referred to as UE autonomous resource selection. In Mode 2, the base station 503 provides a sidelink transmission / reception resource pool for V2X in system information, and the transmitting terminal 501 can allocate transmission resources according to a predetermined rule. Unlike Mode 1 in which the base station directly allocates resources, in FIG. 5, the transmitting terminal 501 autonomously allocates resources based on the resource pool previously received via system information to transmit data.

[0064] 5, a transmitting terminal 501 and a receiving terminal 502 camping on 505 can receive an SL-SIB (510) from a base station 503. Here, the receiving terminal 502 refers to a terminal that receives data transmitted by the transmitting terminal 501. The SL-SIB information may include sidelink resource pool information for sidelink transmission and reception, parameter setting information for sensing operation, information for setting sidelink synchronization, or carrier information for sidelink transmission and reception operating at different frequencies.

[0065] 4 and 5 are different in that in the case of FIG. 4, the base station 503 and the transmitting terminal 501 operate in an RRC connected state, whereas in FIG. 5, the transmitting terminal 501 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 allocate transmission resources. Here, the RRC connection between the transmitting terminal 501 and the base station 503 can be referred to as Uu-RRC 520. When data traffic for V2X is generated in the transmitting terminal 501, a resource pool is set in the transmitting terminal 501 through system information received from the base station 503, and the transmitting terminal 501 can directly select time / frequency domain resources through sensing within the set resource pool (530).

[0066] In the case of broadcast transmission, the transmitting terminal 501 broadcasts SCI(1) to the receiving terminal 502 via the PSCCH without RRC configuration 515 for the side link. st In addition, the transmitting terminal 501 can broadcast data to the receiving terminal 502 via the PSSCH (570). In the case of broadcast transmission, the SCI transmission (2 nd stage SCI, 560) may not be performed.

[0067] In contrast, in the case of unicast and groupcast transmission, the transmitting terminal 501 can establish a one-to-one RRC connection with another terminal. Here, the RRC connection between terminals can be referred to as PC5-RRC 515, in distinction from Uu-RRC. In the case of groupcast, PC5-RRC can also be established individually between terminals in a group. In FIG. 5, the PC5-RRC 515 connection is illustrated as an operation after the transmission of the SL-SIB 510, but it can also be established before the transmission of the SL-SIB 510 or before the transmission of the SCI 550. If an RRC connection between terminals is required, a sidelink PC5-RRC connection is established (515) and the transmitting terminal 501 transmits the SCI (1) to the receiving terminal 502 via the PSCCH. st The SCI (stage) can be transmitted by unicast or groupcast (550). In this case, the groupcast transmission of the SCI can be interpreted as a group SCI. Also, the transmitting terminal 501 transmits the SCI (stage) to the receiving terminal 502 via the PSSCH. nd The 1st stage SCI can be transmitted by unicast or groupcast (560). At this time, the 1st stage SCI contains information related to resource allocation and the 2nd stage SCI. nd Other control information can be included in the stage SCI. In addition, the transmitting terminal 501 can transmit data to the receiving terminal 502 via the PSSCH by unicast or groupcast (570).

[0068] FIG. 6 illustrates a mapping structure of physical channels mapped to one slot in a sidelink according to an embodiment of the present disclosure.

[0069] Specifically, FIG. 6 illustrates mapping of PSCCH / PSSCH / PSFCH physical channels. PSCCH / PSSCH / PSFCH can be allocated to one or more subchannels in frequency. For details on subchannel allocation, refer to the description of FIG. 3. Referring now to FIG. 6 to explain the time mapping of PSCCH / PSSCH / PSFCH, one or more symbols before a transmitting terminal transmits PSCCH / PSSCH / PSFCH 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 further reduced compared to a method of repeatedly transmitting a signal of another channel. When a preamble signal is transmitted for AGC, a specific sequence can be used in the preamble signal 602, and sequences such as PSSCH DMRS, PSCCH DMRS, and CSI-RS can be used in the preamble. In the present disclosure, the sequences used in the preamble are not limited to the above examples. Additionally, referring to FIG. 6, a PSCCH 603 including control information is transmitted in the first symbol of a slot, and data scheduled according to the control information of the PSCCH 603 can be transmitted via a PSSCH 604. The PSCCH 603 includes a part (1) of SCI (sidelink control information) which is control information. st In addition to data, the PSSCH 604 also contains other parts of the SCI (2 nd6 shows that the physical sidelink feedback channel (PSFCH) 605, which is a physical channel for transmitting feedback information, is located at the end of the slot. A predetermined gap can be secured between the PSSCH 604 and the PSFCH 605 so that the UE that transmitted or received the PSSCH 604 can prepare to transmit or receive the PSFCH 605. A predetermined gap can also be secured after the transmission or reception of the PSFCH 605.

[0070] FIG. 7 is a diagram illustrating a scenario in which terminals cooperate with each other to receive resource allocation-related information from other terminals according to an embodiment of the present disclosure.

[0071] Specifically, FIG. 7 illustrates a sidelink scenario for UE cooperation. In FIG. 7, UE-A corresponds to a UE that provides information for UE cooperation, and UE-B corresponds to a UE that receives the information for UE cooperation and performs sidelink transmission. Note that the UEs can be vehicular UEs and pedestrian UEs. In this case, the information for UE cooperation may be resource allocation information. However, the present invention does not limit the information for UE cooperation to resource allocation information. Although FIG. 7 defines UE-A as a UE that provides information for UE cooperation, information 701 for cooperation between the two UEs can be shared between UE-A and UE-B before UE-A provides the information for UE cooperation to UE-B. In this case, information 701 for cooperation between the two UEs can be provided by UE-A to UE-B, or by UE-B to UE-A, or can be provided in both directions between the two UEs (UE-A and UE-B). In addition, the present invention does not assume a specific transmission method in an environment for UE cooperation from a sidelink. In other words, application to broadcast, unicast, and groupcast transmissions can all be considered. However, as mentioned above, it should be noted that unicast and groupcast transmission environments can be useful scenarios for UE cooperation. The conditions for UE cooperation in the sidelink can be activated by the network in a higher layer or by (pre-)configuration. Alternatively, whether or not to cooperate can be configured via PC5-RRC between UEs. In other words, when UE cooperation is activated, UE-A can provide information for UE cooperation, and UE-B can use this information to perform sidelink transmission.

[0072] In FIG. 7, as an example of cooperation between UEs UE-A and UE-B, a scenario can be considered in which UE-A provides resource allocation information to UE-B. In this case, the resource allocation information provided by UE-A may be one or more resource pool candidate information for UE-B. Alternatively, the resource allocation information provided by UE-A may be one or more assigned resource candidate information for UE-B. If the resource pool candidate information is resource pool candidate information, UE-B can allocate resources from one of the resource pools provided by UE-A to perform sidelink transmission. As described above, a resource pool indicates a time and frequency domain in which resources can be allocated for the sidelink. The UE can receive transmission resources from the base station within the resource pool or can allocate transmission resources by directly sensing and allocating resources. If the resource allocation information provided by UE-A is assigned resource candidate information, the assigned resource candidate information may be a resource candidate allocated in the resource pool, and UE-A may expect UE-B to perform sidelink transmission from the resource and receive sidelink transmission from UE-B from the resource. Therefore, UE-B can perform sidelink transmission from the assigned resource candidate provided by UE-A. Here, UE-B may or may not use the resource allocation information provided by UE-A.

[0073] In Figure 7, UE-A and UE-B may be terminals that are IC (In-Coverage) located within the coverage of the base station, or PC (Partial Coverage) or OOC (Out-of Coverage) located outside the coverage of the base station, as shown in Table 1 below.

[0074] [Table 1]

[0075] In Case A in Table 1, since UE-A and UE-B are both located within the base station coverage, UE-A can provide UE-B with resource allocation information set by the base station. If UE-A and UE-B are located within the coverage of different base stations, UE-B information for resource allocation can be exchanged between the base stations. In Case B in Table 1, UE-A is located within the base station coverage but UE-B is located outside the base station coverage, so in order for UE-A to provide UE-B with resource allocation information set by the base station, UE-B information for resource allocation can be provided to the base station to which UE-A belongs. In Cases A and B in Table 1, UE-A can directly perform sensing and resource allocation operations for resource allocation for UE-B, and can provide resource allocation information to UE-B. In Cases C and D in Table 1, since UE-A is located outside the base station coverage, the only way UE-A can directly perform sensing and resource allocation operations to allocate resources for UE-B and provide resource allocation information to UE-B is for UE-A to directly perform sensing and resource allocation operations to allocate resources for UE-B.

[0076] In Case A of Table 1, if two UEs are in the coverage area of ​​the same base station, the same resource pool may be configured for UE-A and UE-B. However, in general, the resource pool information configured for sidelink transmission for UE-A and UE-B may differ. Furthermore, one or more resource pools may be configured for each UE for the sidelink. If multiple resource pools are configured for a UE for the sidelink, the UE may select one suitable resource pool for transmission and perform sidelink transmission from that resource pool. For example, consider the case where resource pools A, B, and C are assigned to UE-A and resource pools D and E are assigned to UE-B. When UE-A and UE-B cooperate with each other, the following cases may be considered for the resource pool used by UE-B for sidelink transmission in a scenario where UE-A provides resource allocation information to UE-B.

[0077] *Case-1: UE-B performs sidelink transmission using the resource pool configured for UE-B

[0078] *Case 2: UE-B performs sidelink transmission using a resource pool configured for UE-A that is not configured for UE-B.

[0079] *Case 3: UE-A and UE-B perform sidelink transmission in a resource pool configured for cooperation between UEs.

[0080] In Case-1 above, in order for UE-A to provide resource allocation information to UE-B, information on resource pools D and E allocated to UE-B must be shared with UE-A. In Case-2 above, in order for UE-B to use the resource allocation information provided by UE-A, information on resource pools A, B, and C allocated to UE-A must be shared with UE-B. In Case-3 above, UE-A and UE-B perform inter-UE cooperation using a shared resource pool. For example, UE-A and UE-B can perform inter-UE cooperation using shared resource pools F and G. Therefore, in all cases of Table 1, in order for UE-A and UE-B to perform inter-UE cooperation and for UE-A to provide resource allocation information to UE-B, resource pool information between the UEs must be shared. For details on this, please refer to the first embodiment below.

[0081] Next, when UE-A and UE-B cooperate with each other and UE-A provides resource allocation information to UE-B, as described above, the resource allocation information provided by UE-A may be information on one or more allocated resource candidates for UE-B. At this time, in order for UE-A to provide resource allocation information to UE-B, resource pool information must be shared between the terminals. Specifically, UE-A can be allocated transmission resources from the base station or can be allocated transmission resources directly through sensing and resource allocation. To achieve this, UE-A must be provided with information related to resource allocation for UE-B. Furthermore, when UE-A instructs resource allocation, it can interpret the indicated resource allocation information as sharing resource pool information between UE-A and UE-B. First, the information provided by UE-B to UE-A may include the following. The following information is for illustrative purposes only, and the resource allocation-related information provided by UE-B to UE-A in the present invention is not limited to the information below.

[0082] Information provided by UE-B to UE-A to provide resource allocation information

[0083] *TX priority for UE-B

[0084] *Remaining Packet delay budget (PDB) for UE-B

[0085] *BSR (Buffer State Report) to UE-B

[0086] *HARQ feedback for UE-B is enabled / disabled

[0087] *Mode 2 resource allocation information for UE-B

[0088] Among the above information, the Remaining PDB for UE-B may be information corresponding to the latency or delay requirement for a packet. Among the above information, the Mode 2 information for UE-B may include information such as Lsubch. Here, Lsubch is the number of consecutive subchannels on the frequency of resource candidates when UE-B allocates resources through Mode 2. However, a method in which Lsubch is not signaled but is directly selected by UE-A may be considered. In this case, UE-A must indicate Lsubch information to UE-B through the resource allocation information of UE-B. In the present invention, the Mode 2 resource allocation information for UE-B is not limited to Lsubch information. Therefore, when UE-A receives one or more of the above information from UE-B, UE-A may also transmit this information to a base station within its coverage via Uu RRC. In this way, when the resource allocation information of UE-B is provided to the base station to which UE-A belongs, UE-A may be allocated transmission resources for UE-B from the base station.

[0089] The following embodiment proposes a procedure (Mode 2) in which a terminal performs sensing and resource allocation in the sidelink as described above. A Mode 2 method is also proposed to minimize power consumption of the terminal. To this end, a method for cooperation between terminals receiving resource allocation-related information from other terminals is proposed. The following describes the operation of the terminal and base station accordingly. The following embodiments of the present disclosure can be applied to terminals that communicate in any communication environment, including unicast, groupcast, and broadcast between terminals.

[0090] <First Example>

[0091] The first embodiment proposes a method for sharing resource pool information when UEs cooperate in the sidelink. It has been explained with reference to FIG. 7 that resource pool information must be shared between UE-A and UE-B when UE-A and UE-B cooperate and UE-A provides resource allocation information to UE-B. A resource pool indicates a time and frequency domain in which resources can be allocated in the sidelink. Various parameters related to the resource pool, as well as information about the time and frequency domain in which resources can be allocated, can be configured as information about the resource pool. For example, Table 2 shows an example of parameter information included in a resource pool in LTE V2X. For example, referring to Table 2, cbr-pssch-TxConfigList-r14 can be configured for each resource pool, and transmission parameters can be determined according to CBR measurement results based on the cbr-pssch-TxConfigList-r14.

[0092] [Table 2]

[0093] As another example, Table 3 shows an example of parameter information included in a resource pool in NR V2X. For example, referring to Table 3, sl-MCS-Table-r16 is configured for each resource pool, and support for the configured MCS table can be determined.

[0094] [Table 3]

[0095] As shown in Tables 2 and 3, various parameters related to the resource pool can be configured as well as time and frequency domain information for allocating resources to the resource pool. Therefore, a large amount of information may be required to share resource pool information between terminals. Therefore, the following method can be considered for sharing resource pool information between terminals.

[0096] Method for sharing resource pool information between terminals - Patents.com

[0097] *Method 1: Setting via PC5-RRC

[0098] *Method 2: Setting through SL MAC CE

[0099] *Method 3: Setting through 2nd stage SCI

[0100] First, Method 1 is a method of sharing resource pool information through a PC5-RRC connection established between terminals in the sidelink. Method 2 is a method of sharing resource pool information through a MAC CE when a PC5-RRC connection is established in the sidelink. Method 3 is a method of sharing resource pool information through a MAC CE when a PC5-RRC connection is established in the sidelink. ndThis is a method of sharing resource pool information via stage SCI. Assume that UE-A and UE-B in FIG. 7 share resource pools A, B, and C through this method. At this time, the shared resource pool may correspond to Case 1 / 2 / 3 described in FIG. 7. In other words, resource pools A, B, and C may be resource pools assigned to UE-B (Case 1), resource pools assigned to UE-A (Case 2), or resource pools shared for cooperation between UEs independently of the resource pools assigned to UE-A and UE-B (Case 3). At this time, the maximum number of resource pools to which each UE can be assigned may be determined. If the maximum number of resource pools to which each UE can be assigned is limited to X, and if the number of resource pools configured for the UEs due to the shared resource pools between the UEs exceeds X, the resource pools that can be shared between the UEs may be limited, or a method of overwriting the resource pools previously assigned to the UEs may be considered.

[0101] In the present invention, the methods for sharing resource pool information are not limited to the above methods 1 to 3. In addition, a combination of the above methods may be considered for the method of sharing resource pool information. For example, the following combinations may be considered:

[0102] *Method 1+2: A method of indicating the resource pool index to be shared via SL MAC CE after multiple resource pool information is shared via PC5-RRC

[0103] *Method 1+3: After multiple resource pool information is shared via PC5-RRC, nd How to specify the resource pool index to share via stageSCI

[0104] *Method 2+3: After multiple resource pool information is shared via SL MAC CE, ndHow to specify the resource pool index to share via stage SCI

[0105] The combination of the above methods may be a more effective method when multiple resource pools are configured and information on one or more resource pools needs to be shared for cooperation between UEs. For example, in the case of Method 1+2, after resource pools A, B, and C between UE-A and UE-B are shared via PC5-RRC, resource pool A can be shared via an SL MAC CE indicating an index corresponding to resource pool A. Alternatively, after resource pools A, B, and C between UE-A and UE-B are shared via PC5-RRC, resource pools A and B can be shared via an SL MAC CE indicating an index corresponding to resource pools A and B. When information on multiple resource pools is shared, the amount of information related to the resource pools that needs to be shared increases, but this problem can be alleviated by combining the above methods.

[0106] If multiple resource pools are shared due to cooperation between terminals, a method for selecting a resource pool to use based on the CBR of the resource pool may be considered. First, the CBR measured in a specific slot n can be defined as follows:

[0107] *CBR can be defined as the percentage of subchannels in which the sidelink RSSI (received signal strength indicator) measured by the terminal in the resource pool exceeds a (pre-set) threshold. Here, CBR measurement can be performed in slot [nX, n-1], and the slot index can be based on the physical slot index.

[0108] **From a transmission perspective, CBR measurement can be performed simultaneously for both the PSSCH region and the PSCCH region. Referring to FIG. 6, a PSSCH related to a portion of the PSCCH can be transmitted using frequency resources that do not overlap with the PSCCH and time resources that overlap with the PSCCH. Alternatively, for another example, a PSSCH related to at least a portion of the PSCCH can be transmitted using non-overlapping time resources. Here, the term "related" means that the PSCCH includes at least information necessary for decoding the PSSCH. As described above, when the PSCCH and the PSSCH are multiplexed, CBR measurement can be performed simultaneously for the two regions without distinguishing between the PSSCH region and the PSCCH region, assuming that the transmit power of the PSCCH region and the PSSCH region is constant and the corresponding RSSI can be measured in the same way for the PSCCH region and the PSSCH region. Specifically, in FIG. 6, RSSI can be measured for symbols in the PSCCH region and the PSSCH region. When PSCCH and PSSCH are multiplexed as shown in Figure 6, it may be difficult for the UE to distinguish between the PSCCH region and the PSSCH region when measuring the CBR. Therefore, the PSCCH region and the PSSCH region may not be distinguished, and the CBR may be measured for all symbols in the PSCCH region and the PSSCH region.

[0109] **X is the value of the window size in which CBR is measured, and X may be a fixed value or a configurable value. For example, when X is a fixed value, X may be set to 100 slots. When X is a configurable value, the configured value of X may be included in the resource pool configuration information. Before the UE establishes an RRC connection with the base station, the value may be pre-configured for the UE, or the UE may be configured from the base station via an SIB. After the UE establishes an RRC connection with the base station, X may be configured to be UE specific. X may also be configured via a PC5-RRC connection between the UE and the UE. For example, X may be configured via the resource pool configuration information as one of {100·2μ, 100} slots. Here, μ is an index corresponding to numerology and is set to the following value according to the subcarrier spacing (SCS):

[0110] ***SCS=15kHz, μ=0

[0111] ***SCS=30kHz, μ=1

[0112] ***SCS=60kHz, μ=2

[0113] ***SCS=120kHz, μ=3

[0114] Of the two setting methods, when X=100·2μ is set, the number of slots in the CBR window corresponding to 100 ms is changed according to the SCS, and when X=100 is set, the CBR window is fixed at 100 slots regardless of the SCS. Therefore, when X=100 is set, the measurement time (ms) of the CBR window can change.

[0115] **Sidelink RSSI means received signal strength. That is, sidelink RSSI indicates the power (unit: [W]) received by the receiving terminal, and is observed based on the valid OFDM symbol position of the channel in the sidelink slot and the configured subchannel.

[0116] According to the definition of CBR, it can be determined whether a channel is congested based on the measured CBR value. The terminal can report the measured CBR to the base station. Specifically, when the base station and terminal are connected via Uu-RRC, the CBR value measured by the terminal can be reported to the base station via Uu-RRC. In Mode 1 of the sidelink resource allocation scheme, when the transmitting terminal requests transmission resources for sidelink communication with the receiving terminal from the base station, the base station can allocate transmission resources using the reported CBR information. On the other hand, in Mode 2 of the sidelink resource allocation scheme, the terminal not only directly allocates resources through sensing but also determines whether to access a channel and transmission parameters based on the CBR measured by the terminal. Therefore, in Mode 2, the terminal can perform congestion control by measuring the channel occupancy ratio (CR) together with the CBR measurement. In this case, the priority of the packet can be reflected. When the transmitting terminal transmits a package, a value indicating the priority of the packet can be transmitted to the receiving terminal via the SCI. The CR is an index indicating the degree to which a terminal occupies a channel, and a CR limit by which a terminal can occupy a channel can be determined according to the CBR value. For example, if the channel is congested (i.e., if the CBR value is measured high), the CR limit is set low, and the terminal can perform congestion control so that the measured CR does not exceed the CR limit. To perform congestion control, the terminal can drop transmission or implement scheduling to make the measured CR satisfy the CR limit. If the channel is not congested (i.e., if the CBR value is measured low), the CR limit is set high, and the measured CR is more likely not to exceed the CR limit, allowing the terminal to occupy and use the channel more.

[0117] However, the CBR values ​​measured by the UEs transmitting and receiving in the sidelink may be different from each other. For example, in FIG. 7, when UE-B is a UE performing sidelink transmission and UE-A is a UE that performs UE-to-UE cooperation, provides resource allocation information to UE-B, and receives sidelink transmission from UE-B, the CBR value measured by UE-A and the CBR value measured by UE-B may be different. For example, since there are few UEs distributed around UE-B, the CBR may be measured low, while there are many UEs distributed around UE-A, the CBR may be measured high. Therefore, in the process of sharing resource pool information between UEs, the CBR information measured by each UE may also be shared. For example, assuming that UE-A and UE-B share resource pools A, B, and C in FIG. 7, the CBR information measured by UE-A and the CBR information measured by UE-B for each resource pool may be shared between UE-A and UE-B. Specifically, the following CBR information may be shared between UEs.

[0118] *In resource pool A, the CBR information measured by UE-A and the CBR information measured by UE-B may be different from each other, and this CBR information may be shared between UE-A and UE-B.

[0119] *In resource pool B, the CBR information measured by UE-A and the CBR information measured by UE-B may be different from each other, and this CBR information may be shared between UE-A and UE-B.

[0120] *In resource pool C, the CBR information measured by UE-A and the CBR information measured by UE-B may be different from each other, and this CBR information may be shared between UE-A and UE-B.

[0121] In this case, the CBR can be shared using the above-described resource pool sharing methods 1 to 3 or a combination thereof. Also, if CBR information between terminals is shared as described above, the following methods can be considered as a method for selecting one resource pool to use from multiple resource pools based on the CBR of each resource pool.

[0122]

number

[0123] In the above formula, i is an index indicating UE-A or UE-B in Figure 7, and j is an index indicating a resource pool. According to the above formula, a terminal can select a resource pool having the lowest CBR value based on the larger value of the CBR values ​​measured by two terminals from multiple resource pools.

[0124] <Second Example>

[0125] The second embodiment provides a method for UE-B to request resource allocation from UE-A when UE-B cooperates with UEs in the sidelink, as shown in FIG. 7. This can be interpreted as an operation in which UE-B transmits a Scheduling Request (SR) to UE-A. For UE-B to send an SR to UE-A, UE-B can transmit the SR to UE-A if the remaining packet delay budget (PDB) for UE-B's package transmission is sufficiently large, taking into account the delay caused by UE-B's cooperation with UE-A. If this condition is not met, the information received when UE-B requests resource allocation from UE-A may not be useful. Assuming that this condition is met, the following method for UE-B to request an SR from UE-A can be considered. In the following description of the embodiments, SR (Scheduling request) is named as an example only and does not limit the present invention. The operation described in the second embodiment may include any operation for UE-B to request resource allocation from UE-A when performing cooperation between terminals in a sidelink, i.e., for requesting inter-UE coordination, and SR (scheduling request) may be replaced with any message or signaling for requesting the resource allocation information. How UE-B requests SR from UE-A

[0126] *Method 1: Request through SL MAC CE

[0127] *Method 2: Request through 1st stage SCI

[0128] *Method 3: Request through 2nd stage SCI

[0129] First, Method 1 is a method of sharing resource pool information via the sidelink MAC CE when a PC5-RRC connection is established on the sidelink. Methods 2 and 3 are respectively st stage SCI and 2nd This is a method of sharing resource pool information via stage SCI. When using Method 2, one of the Rel-16 side links st Since the stage SCI does not have a field related to SR, it has a problem that it cannot be applied to existing UEs. The method of requesting an SR in the present invention is not limited to the above method. In addition, when UE-B transmits an SR to UE-A, it can also transmit part of the above-mentioned 'information provided by UE-B at UE-A to receive resource allocation information'. However, since the signaling overhead for providing the 'information provided by UE-B at UE-A to receive resource allocation information' is very large, a method other than Method 2 can be used.

[0130] Next, when UE-B requests an SR from UE-A, UE-A receives the SR and then requests resource allocation for UE-B from the base station to which UE-A belongs, or UE-A can allocate resources for UE-B through direct sensing and provide resource allocation information to UE-B. For a detailed method of UE-A allocating resources for UE-B through direct sensing, please refer to the following fourth embodiment. In this embodiment, a case will be described in which UE-A receives an SR from UE-B but is unable to provide resource allocation information to UE-B. For a detailed method of a case in which UE-A receives an SR from UE-B and provides resource allocation information to UE-B, please refer to the following third embodiment. First, the following cases can be considered as cases in which UE-A receives an SR from UE-B but is unable to provide resource allocation information to UE-B.

[0131] *Case-1: UE-A operates in the exceptional pool

[0132] *Case-2: When it is determined that cooperation between terminals is impossible due to delay

[0133] In Case-1, when UE-A performs handover, UE-A operates in the exceptional pool. In this case, UE-A finds it difficult to request resource allocation for UE-B from the base station. Furthermore, when operating in the exceptional pool, UE-A makes random selection during direct resource allocation, making it difficult to provide valid resource allocation information to UE-B. Case-2 may occur when UE-A requests resource allocation for UE-B from the base station to which it belongs, or when UE-A allocates resources for UE-B through direct sensing, and the resource allocation information it attempts to provide to UE-B is no longer valid due to a delay generated during the cooperation process between UEs. For example, this may occur when it is determined that the PDB for UE-B's resource transmission is Xms or that resources for UE-B cannot be selected within Xms. In the present invention, the cases in which UE-A cannot provide resource allocation information to UE-B are not limited to the above cases. When UE-A receives an SR request from UE-B but determines that it cannot provide resource allocation information to UE-B, it may consider a corresponding response operation. For example, UE-A can simply signal whether it can provide resource allocation information to UE-B via 1-bit information, and indicate it via SL MAC CE. nd A method of indicating whether UE-A can provide resource allocation information to UE-B may be considered, however, the above method is merely an example, and the method of indicating whether UE-A can provide resource allocation information to UE-B in the present invention is not limited to the above method.

[0134] <Third Example>

[0135] The third embodiment provides a method for UE-A to provide resource allocation information to UE-B when UE-B cooperates via sidelink as shown in Figure 7. When UE-B transmits an SR to UE-A according to the second embodiment, UE-A can request resource allocation for UE-B from the base station to which UE-A belongs after receiving the SR, or UE-A can directly allocate resources for UE-B through sensing and provide resource allocation information to UE-B. In this case, the following methods can be considered as a method for UE-A to provide selected resource allocation information to UE-B.

[0136] How UE-A provides resource allocation information to UE-B

[0137] *Method 1: Providing resource allocation information through SL MAC CE

[0138] *Method 2: Providing resource allocation information through 1st stage SCI

[0139] *Method 3: Providing resource allocation information through 2nd stage SCI

[0140] First, Method 1 is a method of signaling resource allocation information via sidelink MACCE when a PC5-RRC connection is established on the sidelink. Methods 2 and 3 are each a method of signaling resource allocation information via sidelink MACCE when a PC5-RRC connection is established on the sidelink. st stage SCI and 2 nd This is a method of signaling resource allocation information via the first stage SCI. When using Method 2, there is a problem that it cannot be applied to existing terminals because there is no related field in the 1st stage SCI of the Rel-16 sidelink. However, stThe stage SCI has a field indicating resource allocation information reserved by the terminal for sidelink transmission. This is different so that the terminal receives this information and uses it to allocate transmission resources. In one embodiment, a method can be considered in which UE-A and UE-B interpret this field as resource allocation information indicated by UE-A to UE-B, rather than resource allocation information reserved by UE-A. This is st This can be achieved by introducing an additional 1-bit field into the stage SCI to indicate whether the field is resource allocation information reserved by UE-A or resource allocation information instructed by UE-A to UE-B. In the present invention, the method by which UE-A provides resource allocation information to UE-B is not limited to the above method.

[0141] In addition, the resource allocation information from UE-A to UE-B may include the following:

[0142] *Initial resource location information for the same TB

[0143] *Retransmission resource location information for the same TB

[0144] First, the resource allocation information may include location information of an initial resource for at least one TB. In the present invention, it may be assumed that the number of subchannels on the frequency of the initial resource and the retransmission resource is the same. If they are different, additional information must be indicated. Therefore, the resource location information may be information on the time location of the transmission and the subchannel start position on the frequency. Generally, when a terminal allocates resources for its sidelink transmission in sidelink Mode 2 operation, the location information of the initial resource is determined by the location information transmitted by the PSCCH, and therefore, there is no need to separately signal this information. However, when UE-A provides resource allocation information to UE-B via sidelink cooperation as in the present invention, UE-A must additionally indicate location information of the initial resource (the time location and the subchannel start position on the frequency) to UE-B. At this time, the following methods may be considered for determining the time location.

[0145] *Alt-1: Indicates the offset based on the first slot of the determined PSSCH resource pool, based on the SFN (System Frame Number) or DFN (Direct Frame number).

[0146] *Alt-2: When UE-A indicates resource allocation information to UE-B, the first slot belonging to the PSSCH resource pool after the slot in which it is received is determined as the time position of the initial transmission.

[0147] Also, as described above, when UE-A indicates to UE-B the location of the initial and retransmission resources for the same TB via resource allocation information, UE-B can also perform periodic resource reservation based on the resource location for the TB indicated by UE-A, based on the reservation period (resource reservation period, P) indicated by the upper layer.

[0148] <Fourth Example>

[0149] The fourth embodiment provides a method in which UE-A provides resource allocation information to UE-B through a direct sensing and resource allocation process (Mode 2) when cooperation between UEs is performed via the sidelink as shown in Fig. 7. Fig. 8 is a diagram for defining a sensing window and a resource selection window required for UE-A to perform resource (re)selection and reevaluation for resource allocation to UE-B according to an embodiment of the present disclosure.

[0150] Specifically, FIG. 8 illustrates an example in which resource (re)selection is triggered at time n, and sensing is continued even after the (re)selection triggering time n, and triggering for re-evaluation is performed at time n' (n'>n). The condition for triggering resource (re)selection may be when a terminal receives a resource allocation request from another terminal. Specifically, in FIG. 7, this may be when UE-B transmits an SR to UE-A and UE-A receives it. When resource (re)selection triggering is first generated at time n, if the re-evaluation condition is satisfied at time n' (n'>n) after the resource is selected but before reservation for the selected resource is signaled via SCI, triggering for resource (re)selection may be generated again.

[0151] When triggering for resource (re)selection is performed at time n, the sensing window 801 is [n-T0, nT proc,0 ) where T0 can be pre-configured with resource pool information at the start of the sensing window. For example, T0 may be an integer number in ms, but the present disclosure does not limit T0 to a specific value. proc,0can be defined as the time required to process the sensing result. proc,0 The value set by T is not limited to a specific value. proc,0 If is defined in terms of an integer quantity in ms or slots, the sensing window 801 is [n-T0, nT proc,0 In addition, the sensing window may refer to a section that is converted into a logical slot that belongs to a resource pool before slot n and set.

[0152] Next, when triggering for resource (re)selection is performed at time n, the resource selection window (802) is [n+T X ,n+T2], where T X can be determined by the following conditions:

[0153] *T X =T1if T d <T1

[0154] *T X =T d if T d ≧T1

[0155] Here, T1 is a value in slot units, and T1 ≤ T proc,1 can be selected by the terminal implementation. proc,1 can be defined as a maximum reference value that takes into account the processing time required to allocate resources. For example, the value T proc,1 can be fixed at 4 ms. d can be defined as a value reflecting the delay generated in performing cooperation between UEs from the sidelink, and can be set via a higher layer. proc,1 and T d The value set by T is not limited to a specific value. X T with larger slot unit value 2minThe terminal can select a range that satisfies the following condition: ≦T2≦Remaining Packet Delay Budget (PDB). 2min This is to prevent the terminal from selecting a too small value of T2. 2min Value 'T 2min (priority)' can be set via higher layers.

[0156] Next, an operation of continuously performing sensing and performing re-evaluation even after triggering resource (re)selection at time n can be considered. If it is determined that the selected resource is not suitable for transmission through continuous sensing after triggering resource (re)selection at time n and allocating transmission resources, triggering to change the already selected resource 803 at time n' (n'>n) can be defined as re-evaluation. At this time, resource 806 can be reselected depending on the condition for triggering re-evaluation. An operation of triggering re-evaluation of the resource selected at time n' (n'>n) after time n when the UE triggers resource (re)selection can be performed if the UE does not reserve the resource 803 selected in triggering resource (re)selection. At this time, the reservation of the resource can be interpreted as an operation of providing information about the selected resource to another UE. Therefore, the condition can be defined before UE-A indicates information about the resource selected for UE-B via the 'Method for UE-A to Provide Resource Allocation Information to UE-B' in Figure 7. Figure 8 shows both a sensing window 804 and a resource selection window 805 for time n' (n'>n) that triggers re-evaluation.

[0157] In the present invention, when UE-A is defined as a terminal that provides information for UE-to-UE cooperation and UE-B is defined as a terminal that receives information for UE-to-UE cooperation and performs sidelink transmission, UE-A performs an operation of identifying candidate resources for resource allocation within a resource selection window and an operation of allocating resources for transmission from the identified resource candidates, and performs N≦N for one TB. max The UE-B can allocate resources and transmit frequency-time resource allocation information therefor to the UE-B.

[0158] <Fifth Example>

[0159] In the fifth embodiment, an overall flowchart for performing inter-UE cooperation via a sidelink through the first to fourth embodiments will be described with reference to Figure 9. In Figure 9, UE-A corresponds to a terminal that provides information for inter-UE cooperation, and UE-B corresponds to a terminal that receives information for inter-UE cooperation and performs sidelink transmission. The flowchart shown in Figure 9 includes all of the methods proposed in the first to fourth embodiments, but it should be noted that some operations may be omitted or only some operations may be performed in the operation for performing inter-UE cooperation via a sidelink.

[0160] First, 901 in Figure 9 shows an operation of sharing resource pool information when performing cooperation between UEs in a sidelink proposed in the first embodiment. As shown in 901, resource pool sharing can be performed from UE-A to UE-B, from UE-B to UE-A, or in both directions, and refer to the 'Method for Sharing Resource Pool Information Between UEs' in the first embodiment. When one or more resource pools to be used for cooperation between UEs are configured, UE-A can indicate preferred resource pool information to UE-B as in step 902. In one embodiment, if only one resource pool to be used for cooperation between UEs is configured, or if multiple resource pools are configured but the preferred resource pool information can be determined according to a predetermined rule, step 902 can be omitted if separate signaling is not required.

[0161] Next, 903 in Figure 9 shows the operation of UE-B requesting resource allocation from UE-A, as proposed in the second embodiment. This can be interpreted as an operation of UE-B sending a Scheduling Request (SR) to UE-A. At this time, UE-B can transmit information required for UE-A's resource allocation to UE-B to UE-A together with the SR or separately. The relevant information that UE-B can transmit to UE-A for resource allocation is referred to in the above-mentioned 'Information provided by UE-B to UE-A to provide resource allocation information'. When UE-A requests an SR from UE-B, UE-A can request resource allocation for UE-B from the base station, or UE-A can allocate resources for UE-B through direct sensing and provide resource allocation information to UE-B. For detailed operations of UE-A allocating resources for UE-B through direct sensing, refer to the fourth embodiment. When UE-A directly performs sensing to allocate and select resources for UE-B, if the resource pool is a pool that can allocate resources for UE-A's sidelink transmission, the UE can simultaneously perform resource allocation for UE-B and sensing and resource allocation for UE-A's sidelink transmission in the corresponding pool. In this case, the same sensing window and resource selection window may be assumed. However, if the resource pool for allocating resources for UE-B and the resource pool for UE-A's sidelink transmission are separate, the UE can perform sensing and resource allocation operations in each resource pool.

[0162] Finally, 904 in Figure 9 illustrates the operation of UE-A providing resource allocation information to UE-B proposed in the third embodiment. For details on the method of indicating resource allocation information and the resource allocation information, please refer to the third embodiment. When UE-A provides resource allocation information to UE-B, UE-B can operate by simply referring to the information and selecting whether to use it as a sidelink transmission resource. Alternatively, when UE-A provides resource allocation information to UE-B, UE-B can operate by using the information to perform sidelink transmission. In the latter case, UE-B does not need to perform a separate Mode 2 operation for sidelink transmission resource allocation, which is advantageous in that it can reduce power consumption.

[0163] The transmitter, receiver, and processor of a terminal and a base station for carrying out the above-described embodiment of the present invention are shown in Figures 10 and 11, respectively. In the above-described embodiment, a method for a terminal to perform sensing and resource allocation in a sidelink is described, and to perform this, the receiver, processor, and transmitter of the base station and the terminal may each operate according to the embodiment.

[0164] Specifically, FIG. 10 is a block diagram showing the internal structure of a terminal according to an embodiment of the present invention.

[0165] As shown in FIG. 10, the terminal of the present invention may include a terminal receiver 1000, a terminal transmitter 1004, and a terminal processor 1002. The terminal receiver 1000 and the terminal transmitter 1004 may be collectively referred to as a transceiver in the present embodiment. The transceiver may transmit and receive signals to and from a base station. 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 via a wireless channel and output them to the terminal processor 1002, and transmit the signals output from the terminal processor 1002 via the wireless channel. The terminal processor 1002 may control a series of processes so that the terminal operates according to the above-described embodiment of the present invention.

[0166] FIG. 11 is a block diagram showing the internal structure of a base station according to an embodiment of the present invention.

[0167] As shown in FIG. 11, the base station of the present invention may include a base station receiving unit 1101, a base station transmitting unit 1105, and a base station processing unit 1103. The base station receiving unit 1101 and the base station transmitting unit 1105 may be collectively referred to as a transceiver unit in the embodiments of the present invention. The transceiver unit may transmit and receive signals to and from a terminal. The signals may include control information and data. To this end, the transceiver unit 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 unit may receive signals via a wireless channel, output them to the base station processing unit 1103, and transmit the signals output from the base station processing unit 1103 via a wireless channel. The base station processing unit 1103 may control a series of processes so that the base station operates according to the above-described embodiments of the present invention.

[0168] Meanwhile, the embodiments of the present invention disclosed in this specification and drawings are presented as specific examples to facilitate understanding of the present invention and to facilitate easy 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 based on the technical ideas of the present invention are possible. Furthermore, the above-mentioned embodiments can be combined with each other as necessary. For example, all embodiments of the present invention can be partially combined with each other to operate a base station and a terminal. [Explanation of symbols]

[0169] 401 Sending terminal 402 Receiving terminal 403 Base Station 501 Sending terminal 502 receiving terminal 503 base station 1000 Terminal receiver 1002 Terminal processing unit 1004 Terminal transmitter 1101 Base station receiver 1103 Base station processing unit 1105 Base station transmitter

Claims

1. A method in a first terminal of a communication system, comprising: receiving a request for inter-UE coordination information from a second terminal; transmitting the inter-terminal cooperation information to the second terminal; receiving a physical sidelink shared channel (PSSCH) or a physical sidelink control channel (PSCCH) from the second terminal on a resource selected based on the inter-terminal cooperation information; Including, The request for the terminal-to-terminal cooperation information is transmitted on the PSSCH. ｎｄ - Received through stage SCI (sidelink control information) or first SL (sidelink) MAC CE (medium access control element); If the request for the UE cooperation information is received through the first SL MAC CE, the first SL MAC CE includes information on priority and information on the number of subchannels; The inter-UE cooperation information includes time resource information indicating an offset from a reference slot and frequency resource information indicating a position of a start subchannel; The method, wherein the reference slot is determined based on a direct frame number (DFN).

2. The inter-terminal cooperation information is transmitted on the PSSCH. ｎｄ The method according to claim 1, characterized in that the -stage SCI or the second SLMAC CE is transmitted.

3. The method described in claim 1, characterized in that the resource reservation period and resource selection window are indicated by a higher hierarchy.

4. A method in a second terminal of a communication system, comprising: sending a request for inter-UE coordination information to a first terminal; receiving the inter-terminal cooperation information from the first terminal; transmitting a physical sidelink shared channel (PSSCH) or a physical sidelink control channel (PSCCH) to the first terminal using resources selected based on the inter-terminal cooperation information; Including, The request for the terminal-to-terminal cooperation information is transmitted on the PSSCH. ｎｄ - transmitted through the stage SCI (sidelink control information) or the first SL (sidelink) MAC CE (medium access control element); When the request for the UE cooperation information is transmitted through the first SL MAC CE, the first SL MAC CE includes information on priority and information on the number of subchannels; The inter-UE cooperation information includes time resource information indicating an offset from a reference slot and frequency resource information indicating a position of a start subchannel; The method, wherein the reference slot is determined based on a direct frame number (DFN).

5. The inter-terminal cooperation information is transmitted on the PSSCH. ｎｄ The method of claim 4, wherein the first SLMAC CE is received through a -stage SCI or a second SLMAC CE.

6. The method described in claim 4, characterized in that the resource reservation period and resource selection window are indicated by a higher hierarchy.

7. In a first terminal of the communication system, a transmitter / receiver; A control unit configured to receive a request for inter-UE coordination information from a second terminal, transmit the inter-UE coordination information to the second terminal, and receive a physical sidelink shared channel (PSSCH) or a physical sidelink control channel (PSCCH) from the second terminal on resources selected based on the inter-UE coordination information; Including, The request for the terminal-to-terminal cooperation information is transmitted on the PSSCH. ｎｄ - Received through stage SCI (sidelink control information) or first SL (sidelink) MAC CE (medium access control element); If the request for the UE cooperation information is received through the first SL MAC CE, the first SL MAC CE includes information on priority and information on the number of subchannels; The inter-UE cooperation information includes time resource information indicating an offset from a reference slot and frequency resource information indicating a position of a start subchannel; The first terminal is characterized in that the reference slot is determined based on a direct frame number (DFN).

8. The inter-terminal cooperation information is transmitted on the PSSCH. ｎｄ The first terminal according to claim 7, wherein the first SLMAC CE is transmitted through a -stage SCI or a second SLMAC CE.

9. The first terminal described in claim 7, characterized in that the resource reservation period and resource selection window are indicated by a higher hierarchy.

10. In a second terminal of the communication system, a transmitter / receiver; A control unit configured to send a request for inter-UE coordination information to a first terminal, receive the inter-UE coordination information from the first terminal, and transmit a physical sidelink shared channel (PSSCH) or a physical sidelink control channel (PSCCH) to the first terminal using resources selected based on the inter-UE coordination information; Including, The request for the terminal-to-terminal cooperation information is transmitted on the PSSCH. ｎｄ - transmitted through the stage SCI (sidelink control information) or the first SL (sidelink) MAC CE (medium access control element); When the request for the UE cooperation information is transmitted through the first SL MAC CE, the first SL MAC CE includes information on priority and information on the number of subchannels; The inter-UE cooperation information includes time resource information indicating an offset from a reference slot and frequency resource information indicating a position of a start subchannel; The second terminal, wherein the reference slot is determined based on a direct frame number (DFN).

11. The inter-terminal cooperation information is transmitted on the PSSCH. ｎｄ The second terminal according to claim 10, wherein the second SLMAC CE is received through a -stage sidelink control information (SCI) or a second SLMAC CE.

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