KR20200127850A - Method and apparatus for channel state measurement and reporting in sidelink communication - Google Patents

Abstract

The present disclosure relates to a communication technique for fusing a 5^th generation (5G) communication system with an Internet of things (IoT) technology to support a higher data transmission rate than that of a 4^th generation 4G system and a system thereof. The present disclosure can be applied to an intelligent service (for example, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on a 5G communication technology and an IoT-related technology. According to the present disclosure, disclosed is a method for measuring and reporting a channel state in sidelink communication. A control signal processing method in a wireless communication system comprises the steps of: receiving a first control signal transmitted from a base station; processing the first control signal received; and transmitting a second control signal generated based on the processing to the base station.

Description

Method and device for measuring and reporting channel status in sidelink communication {METHOD AND APPARATUS FOR CHANNEL STATE MEASUREMENT AND REPORTING IN SIDELINK COMMUNICATION}

The present invention relates to a mobile communication system, and in particular, a receiving terminal in a process in which a vehicle terminal supporting vehicle-to-everything (V2X) exchanges information using a sidelink with another vehicle terminal and a pedestrian portable terminal. It relates to a method and apparatus for measuring the channel state and reporting it to a transmitting terminal.

Efforts are being made to develop an improved 5G communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of 4G communication systems. For this reason, a 5G communication system or a pre-5G communication system is called a Beyond 4G Network communication system or an LTE system and a Post LTE system. The 5G communication system defined by 3GPP is called the New Radio (NR) system.

In order to achieve a high data rate, the 5G communication system is being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Giga (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) ), array antenna, analog beam-forming, and large scale antenna techniques were discussed and applied to NR systems.

In addition, in order to improve the network of the system, in 5G communication system, advanced small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation And other technologies are being developed.

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

On the other hand, the Internet is evolving from a human-centered network in which humans generate and consume information, to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between objects, machine to machine , M2M), and MTC (Machine Type Communication) technologies are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new value in human life by collecting and analyzing data generated from connected objects can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliance, advanced medical service, etc. through the convergence and combination of existing IT (Information Technology) technology and various industries. Can be applied to.

Accordingly, various attempts have been made to apply a 5G communication system to an IoT network. For example, 5G communication such as a sensor network, machine to machine (M2M), and machine type communication (MTC) is being implemented by techniques such as beamforming, MIMO, and array antenna. As the big data processing technology described above, a cloud radio access network (cloud RAN) is applied as an example of the convergence of 5G technology and IoT technology.

Recently, various studies on sidelink communication have been conducted, and thus, improvement in channel state measurement and reporting is required in sidelink communication.

The present disclosure relates to a wireless communication system, in which a receiving terminal measures a channel state and reports it to a transmitting terminal while a vehicle terminal supporting V2X exchanges information with another vehicle terminal and a pedestrian mobile terminal using a sidelink. It relates to a method and apparatus. Specifically, the present disclosure proposes a method for transmitting a reference signal for measuring a channel state in a sidelink, and a method for measuring and reporting a channel through the same. And it relates to the terminal operation according to the proposed disclosure.

The present invention for solving the above problem is a control signal processing method in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; Processing the received first control signal; And transmitting a second control signal generated based on the processing to the base station.

In the present disclosure, by proposing a method for a receiving terminal to measure a channel state and report it to a transmitting terminal in sidelink communication, the transmission efficiency of the sidelink can always be improved. In addition, the channel state reporting method according to the proposed method can be effectively used for congestion control. And the reference signal transmission method according to the proposed method can be used to support Radio Link Monitoring (RLM) more stably.

1 is an example of a system for describing an embodiment of the present disclosure.
2 is an example of a V2X communication method performed through a sidelink in connection with an embodiment of the present disclosure.
FIG. 3 is a diagram illustrating an example of a resource pool defined as a set (set) of resource resources on time and frequency used for transmission and reception of a sidelink in connection with an embodiment of the present disclosure.
4 is a diagram illustrating an example of a method of allocating a scheduled resource (mode 1) in a sidelink according to an embodiment of the present disclosure.
5 is a diagram illustrating an example of a UE autonomous resource allocation (mode 2) method in a sidelink in connection with an embodiment of the present disclosure.
6 is a diagram illustrating an example of a function of a receiving terminal measuring a channel state in a sidelink and reporting it to a transmitting terminal in relation to an embodiment of the present disclosure.
7 is a diagram illustrating a channel state information framework of an NR sidelink system according to some embodiments in connection with an embodiment of the present disclosure.
8 is an example of a method of configuring a Sensing window A and a Sensing window B for sidelink UE autonomous resource allocation (Mode 2) according to an embodiment of the present disclosure.
9 illustrates an example of a process in which a terminal generates SL CSI information in relation to an embodiment of the present disclosure.
10(a), 10(b), and 10(c) are diagrams for explaining a sensing window and a resource selection window required for a Mode 2 terminal to perform resource (re) selection and re-evaluation according to an embodiment of the present disclosure. to be.
11(a) and 11(b) are diagrams illustrating a time-frequency resource reservation method according to an embodiment of the present disclosure.
12 is a diagram illustrating a structure of a terminal according to an embodiment of the present disclosure.
13 is a diagram illustrating a structure of a base station according to an embodiment of the present disclosure.

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

In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure by omitting unnecessary description.

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

Advantages and features of the present disclosure, and a method of achieving them will be apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the present disclosure complete, and those skilled in the art to which the present disclosure pertains. It is provided to completely inform the scope of the present disclosure to the person, and the present disclosure is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

At this time, it will be appreciated that each block of the flowchart diagrams and combinations of the flowchart diagrams may be executed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general purpose computer, special purpose computer or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates a means to perform functions. These computer program instructions can also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular way, so that the computer-usable or computer-readable memory It is also possible to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block(s). Computer program instructions can also be mounted on a computer or other programmable data processing equipment, so that a series of operating steps are performed on a computer or other programmable data processing equipment to create a computer-executable process to create a computer or other programmable data processing equipment. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block(s).

In addition, each block may represent a module, segment, or part of code that contains one or more executable instructions for executing the specified logical function(s). In addition, it should be noted that in some alternative execution examples, functions mentioned in blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order depending on the corresponding function.

In this case, the term'~ unit' used in the present embodiment refers to software or hardware components such as FPGA or ASIC, and'~ unit' performs certain roles. However,'~ part' is not limited to software or hardware. The'~ unit' may be configured to be in an addressable storage medium, or may be configured to reproduce one or more processors. Thus, as an example,'~ unit' refers to components such as software components, object-oriented software components, class components and task components, processes, functions, properties, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays, and variables. The components and functions provided in the'~ units' may be combined into a smaller number of elements and'~ units', or may be further divided into additional elements and'~ units'. In addition, components and'~ units' may be implemented to play one or more CPUs in a device or a security multimedia card. Also, in an embodiment, the'~ unit' may include one or more processors.

In the detailed description of the embodiments of the present disclosure, the wireless access network New RAN (NR) in the 5G mobile communication standard specified by 3GPP, a mobile communication standard standardization body, and a packet core (5G System, or 5G Core Network, or NG Core: Next Generation Core) is the main target, but the main subject of the present disclosure is applicable to other communication systems having a similar technical background with a slight modification within the scope of the present disclosure. It will be possible at the judgment of a person with skilled technical knowledge in the technical field of the present disclosure.

In a 5G system, in order to support network automation, a Network Data Collection and Analysis Function (NWDAF), a network function that provides a function of analyzing and providing data collected from a 5G network network, may be defined. NWDAF can collect/store/analyze information from 5G networks and provide the results to unspecified network functions (NF), and the analysis results can be used independently by each NF.

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

In addition, terms for identifying access nodes, terms for network entities (network entities), terms for messages, terms for interfaces between network entities, and various identification information used in the following description Terms and the like that refer to them are illustrated for convenience of description. Therefore, it is not limited to the terms used in the present disclosure, and other terms that refer to objects having an equivalent technical meaning may be used.

In order to meet the increasing demand for wireless data traffic after the commercialization of 4G communication systems, efforts are being made to develop an improved 5G communication system (NR, New Radio). In order to achieve a high data rate, the 5G communication system has been designed to enable resources in the ultra high frequency (mmWave) band (eg, the 28 GHz frequency band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, unlike LTE, the 5G communication system resources various subcarrier spacings such as 30 kHz, 60 kHz, and 120 kHz, including 15 kHz, and the physical control channel uses Polar Coding. The data channel (Physical Data Channel) uses LDPC (Low Density Parity Check). In addition, as a waveform for uplink transmission, not only DFT-S-OFDM but also CP-OFDM are used. In LTE, HARQ (Hybrid ARQ) retransmission in units of TB (Transport Block) is a resource, whereas 5G may additionally resource HARQ retransmission based on a CBG (Code Block Group) in which several code blocks (CBs) are grouped.

In this way, a plurality of services can be provided to users in a communication system, and in order to provide such a plurality of services to users, a method and apparatus using the same are required to provide each service within the same time period according to characteristics. . Various services provided in 5G communication systems are being studied, and one of them is a service that satisfies the requirements of low latency and high reliability.

In the case of vehicle communication, LTE-based V2X has been standardized in 3GPP Rel-14 and Rel-15 based on a D2D (Device-to-Device) communication structure, and currently intends to develop V2X based on 5G NR (New Radio). Efforts are going on. NR V2X plans to support unicast communication, groupcast (or multicast) communication, and broadcast communication between the terminal and the terminal. In addition, NR V2X, unlike LTE V2X, which aims to transmit and receive basic safety information necessary for vehicle driving on the road, is a group driving (Platooning), advanced driving (Advanced Driving), extended sensor (Extended Sensor), remote driving (Remote Driving). Together, it aims to provide more advanced services.

Since only broadcast communication was supported in the sidelink of the existing LTE system-based D2D and V2X, the function of the receiving terminal measuring the channel state and reporting it to the transmitting terminal was not supported. In the case of NR V2X, not only broadcast communication but also unicast and groupcast communication between the terminal and the terminal are considered, and since it aims to support advanced services that require more improved transmission efficiency, the receiving terminal reports the channel status to the transmitting terminal. Function is required. Specifically, for measuring and reporting the channel state in the sidelink, the receiving terminal measures the channel using a reference signal transmitted by the transmitting terminal, and using this, the sidelink channel state information (Sidelink Channel State Information) SL CSI) is a function that provides feedback to the transmitting terminal. In this case, the reference signal transmitted by the transmitting terminal to report and receive SL CSI in the sidelink is referred to as SL CSI-RS (Sidelink Channel State Information Reference Signal). When the receiving terminal estimates the channel state using the SL CSI-RS and reports the SL CSI to the transmitting terminal through this, the transmitting terminal can use it to allocate a transmission resource and determine a transmission parameter based on the SL CSI information. In the case of a Uu interface between base station terminals, when the terminal reports SL CSI information to the base station, the base station determines a transmission parameter, which is only referred to, but in the case of the sidelink of V2X, a different operation may be considered. Considering that the sidelink of V2X is inter-terminal communication, a method in which the transmitting terminal must set the transmission parameter with the SL CSI information transmitted by the receiving terminal may be considered. In addition, in the case of the Uu interface between the base station terminals, both periodic/aperiodic CSI-RS transmission and periodic/aperiodic CSI transmission are supported, but in the sidelink, the terminal uses IC (In-Coverage), PC (Partial Coverage) or OCC -of-Coverage), it may be difficult to support periodic SL CSI-RS transmission and periodic SL CSI transmission. Therefore, when periodic SL CSI-RS transmission is not supported, it may be difficult for the receiving terminal to perform Radio Link Monitoring (RLM). In addition, in the sidelink of V2X, the setting range of the transmission parameter may be determined according to whether the corresponding channel is congested. This is a congestion control function in which a terminal determines whether to access a channel when the channel is congested, and sets a transmission parameter to increase a transmission success probability of the terminal when the terminal is connected. Accordingly, the UE measures the Channel Busy Ratio (CBR), and accordingly, the setting range of the transmission parameter may be determined. In addition, the reflection of CBR can be considered together when transmitting SL CSI. In addition, unlike the Uu interface between base station terminals, the sidelink of V2X allocates transmission resources based on a resource pool, and the mode (Mode1) in which the base station sets the allocation of transmission resources and the terminal transmits through direct sensing. A mode for allocating resources (Mode2) is supported. Accordingly, there is a need for a method in which a UE triggers SL CSI transmission, allocates a feedback channel, and transmits and receives SL CSI in consideration of a sidelink transmission resource allocation mode.

In this way, a method for supporting a function of a receiving terminal measuring a channel state and reporting it to a transmitting terminal in the sidelink and the corresponding terminal operation should be defined. However, there is no discussion about this. Accordingly, the present invention proposes a CSI-RS transmission and CSI reporting method suitable for the transmission scenario in the sidelink. Specifically, in the case of unicast operation between the terminal and the terminal in the sidelink, the IC/OCC environment, resource pool-based transmission, transmission resource allocation mode (Mode1/2), RLM support, SL CSI-RS transmission considering CBR, etc. A UE operating method and apparatus for a SL CSI reporting method is proposed.

Embodiments of the present specification are proposed to support the above-described scenario, and particularly, a method and apparatus for a receiving terminal to measure a channel state and report it to a transmitting terminal in a sidelink environment in which unicast and groupcast communication is supported. It aims to provide.

1 is an example of a system for describing an embodiment of the present disclosure.

(A) of FIG. 1 is an example of a case in which all V2X terminals (UE-1 and UE-2) are located within the coverage of a base station (In-Coverage, IC).

All V2X terminals may receive data and control information from the base station through a downlink (DL) or transmit data and control information to the base station through an uplink (UL). At this time, the data and control information may be data and control information for V2X communication. Alternatively, the data and control information may be data and control information for general cellular communication. In addition, V2X terminals may transmit/receive data and control information for V2X communication through a sidelink (SL).

(B) of FIG. 1 is an example of a case in which UE-1 is located within the coverage of the base station and UE-2 is located outside the coverage of the base station among V2X terminals. The example according to FIG. 1(b) may be referred to as an example of partial coverage (PC).

UE-1 located within the coverage of the base station may receive data and control information from the base station through a downlink (DL) or transmit data and control information to the base station through an uplink (UL).

UE-2 located outside the coverage of the base station cannot receive data and control information from the base station through downlink, and cannot transmit data and control information to the base station through uplink.

UE-2 can transmit/receive data and control information for V2X communication with UE-1 through a sidelink.

(C) of FIG. 1 is an example of a case in which all V2X terminals are located out of coverage (OOC) of a base station.

Accordingly, UE-1 and UE-2 cannot receive data and control information from the base station through downlink, and cannot transmit data and control information to the base station through uplink.

UE-1 and UE-2 may transmit/receive data and control information for V2X communication through a sidelink.

1D is an example of a scenario for performing V2X communication between terminals located in different cells. Specifically, in (d) of FIG. 1, when the V2X transmitting terminal and the V2X receiving terminal are connected to different base stations (RRC connection state) or camping (RRC connection release state, that is, RRC idle state). At this time, UE-1 may be a V2X transmitting terminal and UE-2 may be a V2X receiving terminal. Alternatively, UE-1 may be a V2X receiving terminal, and UE-2 may be a V2X transmitting terminal. UE-1 can receive a V2X-only SIB (System Information Block) from the base station to which it is connected (or it is camping), and UE-2 can receive another SIB (System Information Block) to which it is connected (or it is camping). It is possible to receive a V2X dedicated SIB from the base station. At this time, the information of the V2X-only SIB received by UE-1 and the information of the V2X-only SIB received by UE-2 may be different from each other. Accordingly, in order to perform V2X communication between terminals located in different cells, information may be unified, or more flexible parameter setting may be supported through the method and apparatus for setting related parameters of the present invention.

1 illustrates a V2X system consisting of two terminals (UE-1 and UE-2) for convenience of description, but is not limited thereto. In addition, uplink and downlink between the base station and V2X terminals may be referred to as a Uu interface, and a sidelink between V2X terminals may be referred to as a PC5 interface. Therefore, in the present disclosure, these can be mixed and used.

Meanwhile, in the present disclosure, the terminal is a vehicle supporting vehicle-to-vehicle communication (Vehicular-to-Vehicular: V2V), a vehicle supporting vehicle-to-pedestrian communication (Vehicular-to-Pedestrian: V2P), or a handset of a pedestrian (ie, smart Phone), a vehicle supporting communication between a vehicle and a network (Vehicular-to-Network: V2N), or a vehicle supporting communication between a vehicle and a traffic infrastructure (Vehicular-to-Infrastructure: V2I). In addition, in the present disclosure, the terminal may mean an RSU (Road Side Unit) equipped with a terminal function, an RSU equipped with a base station function, or an RSU equipped with a part of a base station function and a part of a terminal function.

In addition, in the present disclosure, it is predefined that the base station may be a base station supporting both V2X communication and general cellular communication, or a base station supporting only V2X communication. In this case, the base station may mean a 5G base station (gNB), a 4G base station (eNB), or a road site unit (RSU). Therefore, unless otherwise specified in the present disclosure, the base station and the RSU may be used in the same concept and may be used interchangeably.

2 is an example of a V2X communication method performed through a sidelink.

As shown in (a) of FIG. 2, the TX terminal and the RX terminal may perform one-to-one communication, and this may be referred to as unicast communication.

As shown in (b) of FIG. 2, the TX terminal and the RX terminal may perform one-to-many communication, and this may be referred to as groupcast or multicast.

In Figure 2 (b), UE-1, UE-2, and UE-3 form a group (group A) to perform groupcast communication, and UE-4, UE-5 , UE-6, and UE-7 are diagrams illustrating performing groupcast communication by forming another group (group B). Each terminal performs groupcast communication only within a group to which it belongs, and communication between different groups may be performed through unicast, groupcast, or broadcast communication. 2(b) shows that two groups are formed, but the present invention is not limited thereto.

Meanwhile, although not shown in FIG. 2, V2X terminals may perform broadcast communication. Broadcast communication refers to a case in which all V2X terminals receive data and control information transmitted by a V2X transmitting terminal through a sidelink. As an example, when it is assumed that UE-1 is a transmitting terminal for broadcast in (b) of FIG. 2, all terminals (UE-2, UE-3, UE-4, UE-5, and UE- 6, and UE-7) may receive data and control information transmitted by UE-1.

In NR V2X, unlike LTE V2X, support in the form of sending data to a specific node through a unicast by a vehicle terminal and sending data to a number of specific nodes through a groupcast can be considered. have. For example, in consideration of a service scenario such as Platooning, a technology that connects two or more vehicles through a single network and moves in a cluster form, such unicast and groupcasting technologies can be usefully used. Specifically, unicast communication may be required for the purpose of a group leader node connected by platooning to control one specific node, and group cast communication may be required for the purpose of simultaneously controlling a group consisting of a specific number of nodes. have.

3 is a diagram illustrating an example of a resource pool defined as a set (set) of resource resources on time and frequency used for transmission and reception of a sidelink.

3-10 are an example of a case in which a resource pool is non-contiguously allocated on time and frequency. Although the present invention focuses on the case where the resource pool is non-contiguously allocated on the frequency, it is noted that the resource pool may be continuously allocated on the frequency.

3-20 are an example of a case in which a resource pool is non-contiguously allocated on a frequency.

In the resource pool, the resource granularity of the frequency axis may be one or more PRBs (Physical Resource Block). In addition, the resource allocation unit on the time axis in the resource pool may be one or more OFDM symbols. As an example, one slot composed of 14 OFDM symbols may be a time axis resource allocation unit within one resource pool.

3-21 is an example of a case in which resource allocation is performed in a sub-channel unit on the frequency axis. The subchannel may be defined as a resource allocation unit on a frequency composed of one or more RBs. In other words, the subchannel may be defined as an integer multiple of RB. 3-21 shows an example in which the size of a subchannel is composed of 4 consecutive PRBs. The size of the sub-channel may be set differently, and one sub-channel is generally composed of a continuous PRB, but there is no limitation that it must be composed of a continuous PRB. The subchannel may be a basic unit of resource allocation for PSSCH (Physical Sidelink Shared Channel), PSCCH (Physical Sidelink Control Channel), and PSFCH (Physical Sidelink Feedback Channel). In this case, the size of the subchannel may be set differently depending on whether the corresponding channel is PSSCH, PSCCH, or PSFCH. In addition, it is noted that the term of the subchannel can be replaced with a term such as RBG (Resource Block Group).

StartRBSubchanel of FIG. 3-22 indicates the start position of a subchannel on a frequency in the resource pool.

3-30 are examples of a case in which non-contiguous resource allocation in time is performed. The granularity of resource allocation in time may be a slot. Although the present invention focuses on a case in which the resource pool is non-contiguously allocated in time, it is noted that the resource pool may be continuously allocated in time.

The startSlot of FIG. 3-31 indicates the start position of a time slot in the resource pool.

4 is a diagram illustrating an example of a method of allocating scheduled resources (mode 1) in a sidelink. In the case of scheduled resource allocation (mode 1), the base station allocates resources used for sidelink transmission to RRC-connected terminals in a dedicated scheduling scheme. The above method can be effective in interference management and resource pool management because the base station can manage the resources of the sidelink.

In FIG. 4, the transmitting terminal 4-01 camping on (4-05) receives (4-10) a SL SIB (Sidelink System Information Block) from the base station 4-03. The system information may include sidelink resource pool information for sidelink transmission/reception, parameter setting information for sensing operation, information for setting sidelink synchronization, and carrier information for sidelink transmission/reception operating at different frequencies. I can. When data traffic for V2X is generated in the transmitting terminal 4-01, it performs RRC connection with the base station (4-20). Here, the RRC connection between the terminal and the base station may be referred to as Uu-RRC (4-20). The Uu-RRC connection process may be performed before data traffic is generated. The transmitting terminal 4-01 requests the base station for a transmission resource capable of V2X communication with the other terminals 4-02 (4-30). Here, 4-02 is a receiving terminal that receives data transmitted by the transmitting terminal. At this time, the transmitting terminal 4-01 may request a sidelink transmission resource from the base station using a physical uplink control channel (PUCCH), an RRC message, or a MAC CE. On the other hand, MAC CE is a buffer status report (BSR: buffer status report) MAC CE of a new format (at least, including an indicator indicating that a buffer status report for V2X communication and information on the size of data buffered for D2D communication). Etc. In addition, a sidelink resource may be requested through a scheduling request (SR) bit transmitted through an uplink physical control channel. The base station 4-03 allocates a V2X transmission resource to the transmitting terminal 4-01 through a dedicated Uu-RRC message. This message may be included in a message in a message (eg, RRCConnectionReconfiguration) that resets parameter information for RRC connection configuration. The resource allocation request information may be a V2X resource through Uu or a resource allocation request for PC5 according to the type of traffic requested by the terminal or whether the corresponding link is congested. For the determination, the UE may add and transmit ProSe Per Packet Priority (PPPP) or Logical Channel ID (LCID) information of V2X traffic through UEAssistanceInformation or MAC CE. The base station 4-03 may instruct the terminal 4-01 for final scheduling by transmitting DCI through the PDCCH (4-40).

Next, in the case of broadcast transmission, the terminal (4-01) broadcasts SCI (Sidelink Control Information) to other terminals (4-02) through the PSCCH by broadcast without additional sidelink RRC configuration (4-15). Cast (4-70). In addition, data is broadcast to other terminals 4-02 through the PSSCH (6-70).

In contrast, in the case of unicast and groupcast transmission, the terminal 4-01 may perform a one-to-one RRC connection with other terminals. Here, the RRC connection between the terminal and the terminal may be referred to as PC5-RRC (4-15) in distinction from the Uu-RRC. Even in the case of a group cas, the PC5-RRC (4-50) is individually connected between the terminals in the group and the terminals. In Figure 4, the connection of the PC5-RRC (4-15) is shown as an operation after 4-10, but can be performed at any time before 4-10 or before 4-60. If RRC connection is required between the terminal and the terminal, PC5-RRC connection of the sidelink is performed (4-50), and SCI (Sidelink Control Information) is unicast and grouped to other terminals (4-02) through PSCCH. Transmit by cast (4-60). Resource allocation information for PSCCH/PSSCH and/or PSFCH may be transmitted through SCI. At this time, the groupcast transmission of SCI may be interpreted as a group SCI. In addition, data is transmitted through unicast and groupcast to other terminals 4-02 through the PSSCH (4-70).

5 is a diagram illustrating an example of a UE autonomous resource allocation (mode 2) method in a sidelink.

In the UE autonomous resource allocation (mode 2), the base station provides a pool of sidelink transmission/reception resources for V2X as system information, and the terminal selects transmission resources according to a set rule. Unlike the scheduled resource allocation (mode 1) method in which the base station directly participates in resource allocation, in FIG. 5, the terminal 5-01 autonomously selects resources and transmits data based on the resource pool previously received through system information. There is a difference in that. In V2X communication, the base station 5-03 may allocate various types of resource pools (V2V resource pool, V2P resource pool) for the terminal 5-01. The resource pool may consist of a resource pool in which the terminal can autonomously select an available resource pool after sensing resources used by other terminals around it, and a resource pool in which the terminal randomly selects a resource from a preset resource pool. have.

The transmitting terminal 5-01 camping on (5-05) receives (5-10) a SL SIB (Sidelink System Information Block) from the base station 5-03. The system information may include sidelink resource pool information for sidelink transmission/reception, parameter setting information for sensing operation, information for setting sidelink synchronization, and carrier information for sidelink transmission/reception operating at different frequencies. I can. The major difference in the operation between FIGS. 4 and 5 is that in FIG. 4, the base station 5-03 and the terminal 5-01 operate in a state in which RRC is connected, whereas in FIG. 5, the idle mode in which RRC is not connected ( 5-20) can also work. In addition, even in a state in which the RRC is connected (5-20), the base station 5-03 may operate so that the terminal autonomously selects a transmission resource without directly involved in resource allocation. Here, the RRC connection between the terminal and the base station may be referred to as Uu-RRC (5-20). When data traffic for V2X is generated in the terminal (5-01), the terminal (5-01) is configured with a resource pool through system information from the base station (5-03), and the terminal performs a transmission operation set within the configured resource pool. Time/frequency domain resources are selected according to (5-30).

Next, in the case of broadcast transmission, the terminal 5-01 broadcasts SCI (Sidelink Control Information) to other terminals 5-02 through the PSCCH by broadcast without additional sidelink RRC configuration (5-20). Cast (5-50). In addition, data is broadcast to other terminals 5-02 through the PSSCH (5-60).

In contrast, in the case of unicast and groupcast transmission, the terminal 5-01 may perform a one-to-one RRC connection with other terminals. Here, the RRC connection between the terminal and the terminal may be referred to as PC5-RRC (5-20), distinguishing from the Uu-RRC. Even in the case of a group cas, the PC5-RRC is individually connected between the terminals in the group and the terminals. In FIG. 5, the connection of the PC5-RRC 5-15 is shown as an operation after 5-10, but may be performed at any time before 5-10 or before 5-50. If RRC connection is required between the terminal and the terminal, PC5-RRC connection of the sidelink is performed (5-40) and SCI (Sidelink Control Information) is unicast and grouped to other terminals (5-02) through the PSCCH. Transmit by cast (5-50). Resource allocation information for PSCCH/PSSCH and/or PSFCH may be transmitted through SCI. At this time, the groupcast transmission of SCI may be interpreted as a group SCI. In addition, data is transmitted by unicast and groupcast to other terminals 5-02 through the PSSCH (5-60).

6 is a diagram illustrating an example of a function of a receiving terminal measuring a channel state in a sidelink and reporting it to a transmitting terminal.

Specifically, in FIG. 6, FIG. 6-10 shows a transmitting end, and FIG. 6-20 shows a receiving end. In general, the transmitting end and the receiving end can be indicated as subjects that transmit and receive data. In the V2X system, the terminal may be a transmitting end or a receiving end. Also, the receiving end of FIGS. 6-20 may be one terminal or multiple terminals. For example, when the receiving end of FIGS. 6-20 is a plurality of terminals, it may be a scenario such as group driving (Platooning). 6-30, a transmitting terminal corresponding to a transmitting end transmits an SL CSI-RS to obtain channel information from a receiving terminal, and a receiving terminal corresponding to the receiving end receives it. In addition, the transmitting terminal may make a request for SL CSI to the receiving terminal. The SL CSI-RS transmission in FIGS. 6-30 includes a method in which an SL CSI-RS resource is set and transmitted, a condition in which an SL CSI-RS is transmitted, and a method for setting an SL CSI-RS pattern, and will be described in detail in the following embodiments. In addition, the SL CSI feedback request includes a channel selection method according to a transmission channel configuration of SL CSI and a transmission resource allocation mode (Mode1/2), an SL CSI triggering/activation method, and a valid SL CSI determination method, which will be described in detail in the following embodiments. . Next, the receiving end measures the channel state of the sidelink as shown in FIGS. 6-40 by using the SL CSI-RS. Next, the receiving end generates information on SL CSI as shown in FIG. 6-50 by using the channel state measurement result. In the following examples, a method of generating SL CSI such as CQI, CQI+RI, or CQI+RI+PMI will be described in detail. In particular, a method of reflecting CBR when generating CQI is also considered. Finally, as shown in FIGS. 6-60, the UE corresponding to the receiving end feeds back the SL CSI to the UE corresponding to the transmitting end. The operation for this will also be described through the following examples.

In the present invention, SL CSI-RS transmission and SL CSI reporting are first limited to a case in which the terminal and the terminal operate in unicast on the sidelink. In other words, SL CSI-RS transmission and SL CSI reporting are not considered in broadcast. In the case of groupcast, SL CSI-RS transmission for groupcast and SL CSI reporting method are not separately considered. However, in the case where the UE and the UE can operate in unicast within a group, the SL CSI-RS transmission and SL CSI reporting method proposed by the present invention may be applied. In the present invention, only aperiodic SL CSI-RS transmission and aperiodic SL CSI transmission are considered. And, when transmitting a multi-rank PSSCH, transmission of up to two layers is considered. In addition, the SL CSI may contain various information. For example, information that may be included in SL CSI includes Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), CSI-RS Resource Indicator (CRI), and SS/PBCH Block Resource Indicator (SSBRI). ), LI (Layer Indicator), and LI-RSRP. In addition, as information that can be included in the SL CSI, a Channel Busy Ratio (CBR) and a Channel Occupancy Ratio (CR) can be considered. In the present invention, a method of feeding back CQI, CQI-RI, or CQI-RI-PMI as information on SL CSI will be described. In addition, an operation in which the receiving terminal feeds back CBR and CR information to the transmitting terminal is proposed. In order for the receiving terminal to provide SL CSI information to the transmitting terminal, the receiving terminal must be configured with resource setting and report setting for channel state information.

In detail, a process of measuring and reporting channel state information between a terminal and a terminal in the NR sidelink system will be described.

7 is a diagram illustrating a channel state information framework of an NR sidelink system according to some embodiments. The CSI framework of FIG. 7 may consist of two elements: resource setting and report setting. The report setting may configure at least one or more links with each other by referring to the ID of the resource setting.

According to an embodiment of the present disclosure, the resource setting may include information related to a reference signal (RS). The base station may set at least one resource setting (7-00, 7-05, 7-15) to the terminal. Each resource setting may include at least one resource set (7-20, 7-25). Each resource set may include at least one resource (7-30, 7-35). Each resource (7-30, 7-35) is detailed information on the RS, for example, transmission band information through which the RS is transmitted (for example, Sidelink bandwidth part, SL BWP), the location of the resource element (RE) through which the RS is transmitted It may include information, RS transmission period and offset in the time axis, and the number of RS ports. As described above, the corresponding RS may be referred to as SL CSI-RS, and when periodic SL CSI-RS is not supported, the RS transmission period and offset information on the time axis may not be included.

According to an embodiment of the present disclosure, the report setting may include information related to the SL CSI reporting method. The base station may set at least one report setting (7-40, 7-45, 7-50) to the terminal. At this time, each report setting is the setting information of enable/disable for SL CSI reporting, the type of channel through which the report is transmitted (e.g., PSSCH (Physical Sidelink Shared Channel) or PSFCH (Physical Sidelink Feedback Channel)), and SL CSI reported. Band information (e.g., SL BWP), configuration information for codebook when PMI is supported, time-domain behavior for SL CSI reporting, frequency granularity for SL CSI reporting, configuration information for measurement restriction, valid SL CSI window configuration information and reportQuantity, which is information included in SL CSI, may be included in the parameter information of SL-CSI-ReportConfig. Specifically, the time-domain behavior for SL CSI reporting is whether the SL CSI report is periodic or non-mainstream. The present invention considers only the case in which the SL CSI report is aperiodically configured, and the frequency granularity for the SL CSI report means a unit on the frequency for the SL CSI report, and in the present invention, the transmission environment of the sidelink Considering that, unlike the Uu interface between the base station terminals, the SL CSI report may transmit a non-subband-based aperiodic SL CSI report through the PSSCH or PSFCH only for the frequency domain in which the corresponding PSSCH is transmitted. When measuring a channel when reporting SL CSI, it means setting whether a time or frequency measurement interval for the channel measurement is restricted.The effective SL CSI window setting information takes into account the CSI feedback delay and when the SL CSI window is crossed, the SL It can be determined that the CSI is not valid, see the relevant detailed description below. Say. Finally, reportQuantity indicates information included in SL CSI, and the present invention considers setting of CQI, CQI-RI, or CQI-RI-PMI. In addition, reportQuantity may include CBR or CR information of the receiving terminal. In this case, the report setting may include at least one ID for referring to information on a channel referenced by the UE or reference signal (or RE location) for interference measurement when reporting CSI. This is illustrated through links (7-60, 7-65, 7-70, 7-75).

According to an embodiment of the present disclosure, when link (7-60) connects one reporting setting (7-40) and one resource setting (7-00), the resource setting (7-00) is channel measurement Can be used for (channel measurement).

According to an embodiment of the present disclosure, when link (7-65, 7-70) connects one reporting setting (7-45) and two resource settings (7-00, 7-05), either The resource setting of can be used for channel measurement, and the remaining resource setting can be used for interference measurement.

According to an embodiment of the present disclosure, resource setting and report setting may be connected to a support pool and may be (pre-)configuration for each resource pool. It may be indicated through SL SIB (Sidelink System Information Block) or UE-specific higher level signaling. When indicated through SL SIB, a corresponding value may be set in resource pool information among corresponding system information. When set through an upper layer, it can be set through Uu-RRC or PC5-RRC. However, depending on whether the terminal is in the IC/PC/OCC environment or the transmission resource allocation mode (Mode1/2) in the side link, the setting method for resource setting and report setting may be different.

It has been described that each resource setting in the channel state information framework of the NR sidelink system may include at least one resource set, and each resource set may include at least one resource. Below, when detailed information on the SL CSI-RS is set in each resource, the conditions and method for transmitting the actual SL CSI-RS are described. Prior to this, in the case of a Uu interface between base station terminals, the CSI-RS is transmitted over the entire band of the configured frequency. In addition, the UE feeds back the CSI report for all frequency bands in the form of wideband or sub-band, so that the base station can receive the CSI report for the entire frequency band. However, considering that the sidelink of V2X is communication between terminals, it is considered that the SL CSI-RS transmission is limited to the transmission region of the PSSCH. In other words, the SL CSI-RS together with the PSSCH may be transmitted only in a frequency domain in which resources are allocated to the PSSCH.

As described above, in the present invention, aperiodic SL CSI-RS transmission is considered. The conditions in which the aperiodic SL CSI-RS is transmitted may consider the following methods.

SL CSI-RS transmission conditions

* Method 1: SL CSI-RS with PSSCH are transmitted only when SL CSI report is enabled and actual SL CSI report is triggered/activated.

* Method 2: When SL CSI reporting is enabled, the SL CSI-RS is transmitted whenever PSSCH is transmitted.

* Method 3: When SL CSI-RS is set for SL RLM (Sidelink Radio Link Monitoring), SL CSI-RS is transmitted every time PSSCH is transmitted, and SL CSI-RS is not set for SL RLM In this case, the SL CSI report is enabled and the SL CSI-RS together with the PSSCH are transmitted only when the actual SL CSI report is triggered/activated.

As described above, SL CSI reporting may be enabled/disabled separately from triggering/activation of actual SL CSI reporting. It has been described that enable/disable for SL CSI reporting can be set in the report setting of the channel state information framework of the NR sidelink system. In addition, note that SL CSI reporting can be triggered/activated only when SL CSI reporting is enabled. Various methods of triggering/activation of SL CSI reporting will be described again below. Specifically, Method 1 is a method in which the SL CSI-RS is transmitted only once through the PSSCH along with signaling for triggering/activating the SL CSI report. A method of triggering/activating SL CSI reporting through signaling will be described in more detail below. Method 2 is non-contiguous when the actual SL CSI report is enabled, unlike Method 1, because SL CSI-RS is transmitted every time PSSCH is transmitted when SL CSI report is triggered/activated. This is a method of transmitting SL CSI-RS together with PSSCH. Therefore, compared to Method 1, more SL CSI-RS samples for measuring channel conditions can be obtained. Method 3 is a method in which the condition for transmitting the SL CSI-RS is determined according to the configuration of the SL RLM. It is determined whether there is a sidelink of RLF (Radio Link Failure), and the receiving terminal can perform RLM using the reference signal sent by the transmitting terminal. Here, signals that the transmitting terminal can send to the receiving terminal to perform SL RLM may include SL CSI-RS, SL DMRS (PSCCH, PSSCH, PSBCH), and S-SSS. If SL CSI-RS is set as the reference signal for SL RLM, the method for securing more SL CSI-RS samples as in Method 2 is used, and SL CSI-RS is set as the reference signal for SL RLM. If not, the method in which the SL CSI-RS is transmitted only once is used as in Method 1. In addition, if the SL CSI-RS is set as the reference signal for the SL RLM, it is possible to force the number of resource blocks (RBs) or subchannels to be transmitted at a certain amount or more on the frequency at which the SL CSI-RS is transmitted. In other words, when the SL CSI-RS is set as the reference signal for the SL RLM, it may be set to secure a frequency domain in which the SL CSI-RS is transmitted. For example, when SL CSI-RS is set as a reference signal for SL RLM, the number of RBs on the frequency at which the SL CSI-RS is transmitted may be forced to transmit 4 RBs or more. At this time, the SL CSI-RS is transmitted after being confine to the PSSCH. The reason why the SL CSI-RS is forcing the frequency domain to be transmitted is to guarantee the performance of the SL RLM through this. Since the SL CSI-RS can estimate a pure channel value, it may be the most preferable signal among the signals for the SL RLM. However, when the SL CSI-RS is not periodically transmitted and is transmitted in a small frequency region, it may be difficult to determine a link state through channel estimation. Accordingly, the present invention proposes a method for securing more time and frequency samples when the SL CSI-RS is set as a signal for SL RLM.

In the present invention, it is assumed that the SL CSI-RS pattern reuses the CSI-RS pattern in the NR Uu system. For the CSI-RS pattern in the NR Uu system, refer to 3GPP standard TS38.211 (Section 7.4.1.5). However, the SL CSI-RS pattern in the present invention is not limited to only the CSI-RS pattern in the NR Uu system. The SL CSI-RS pattern can be defined as another type of pattern. For example, a sounding reference signal (SRS) in an NR Uu system may be defined as an SL CSI-RS pattern or a new SL CSI-RS pattern may be designed. When reusing the CSI-RS pattern in the NR Uu system as the SL CSI-RS pattern, an available pattern may be determined according to the maximum number of SL CSI-RS ports considered in the sidelink. In addition, in the CSI-RS pattern in the NR Uu system, it is possible to set the position of the CSI-RS in time and frequency, but the SL CSI-RS pattern may place restrictions on the position on the settable time and frequency.

Next, a method of selecting a channel according to a transmission resource allocation mode (Mode1/2) and configuration of a channel through which SL CSI is transmitted in the SL CSI feedback request in FIGS. 6-30 will be described. The channel through which SL CSI is transmitted can be considered in the following ways.

SL CSI transmission channel

* Method 1: SL CSI is piggybacked and transmitted through PSSCH with data

* Method 2: SL CSI is transmitted through PSSCH without data (SL CSI only transmission)

* Method 3: SL CSI is transmitted through PSFCH

In the above methods, when the receiving terminal reports the SL CSI to the transmitting terminal through the PSSCH as in Method 1 or Method 2, the channel selection method may be different according to the transmission resource allocation mode (Mode1/2). In the sidelink, a mode in which a corresponding base station sets the allocation of transmission resources as described with reference to FIG. 4 (Mode1) and a mode in which the terminal allocates transmission resources through direct sensing as described through FIG. 5 (Mode2) are supported. . In the case of Mode1, the UE is allocated PSSCH resources from the base station through DCI (Downlink Control Information). Accordingly, the UE may transmit resources to the PSSCH allocated from the base station, and at this time, SL CSI information may be transmitted through the PSSCH (Method 1 or Method 2). In contrast, in the case of Mode2, the UE directly selects the PSSCH resource through sensing. In addition, the transmitting terminal informs the receiving terminal of transmission resource allocation information through Sidelink Control Information (SCI). Therefore, Mode2 can operate not only in IC but also in OCC/PC environment. In Mode2, when the receiving terminal feeds back the SL CSI to the transmitting terminal, the receiving terminal directly determines the PSSCH resource for transmitting the SL CSI through Mode2 sensing and resource selection, and the transmitting terminal through Mode2 sensing and resource selection. A method of requesting feedback from the SL CSI to the determined PSSCH resource can be considered. A more specific method for this will be described in more detail through Embodiment 1 along with the Mode2 sensing and resource selection method. Method 3 is a method in which the receiving terminal reports the SL CSI to the transmitting terminal through the PSFCH. For Method 3, it is assumed that a PSFCH format capable of transmitting SL CSI is defined. In this case, the UE may be allocated PSFCH transmission resources in the resource pool. Unlike the PSSCH transmission resource allocation method, the UE may be configured with a PSFCH transmission resource having a period of N slots (pre-). In more detail, the method of preconfiguration is a method of pre-storing the PSFCH transmission resource period N in the terminal. Unlike this, a PSFCH transmission resource period N value may be set in an upper layer. When using the upper layer, the PSFCH transmission resource period N may be set in Uu-RRC or PC5-RRC. The (pre-)configuration for the PSFCH transmission resource may also include a configuration that does not allocate the PSFCH transmission resource.

If the PSSCH and PSFCH are simultaneously supported as a channel through which SL CSI is transmitted, the UE receiving the SL CSI does not know the information on the channel through which the SL CSI is transmitted, it is uncertain whether the SL CSI is transmitted on the PSSCH or the PSFCH. Will have. In order to solve this problem, the following two methods can be considered.

Setting for the channel through which SL CSI is transmitted (if both PSSCH and PSFCH are supported as a channel through which SL CSI is transmitted)

* Method 1: When the transmitting terminal triggers/activates the SL CSI report, when the receiving terminal feeds back the SL CSI to the transmitting terminal through 1-bit SCI, it determines whether to use PSSCH or PSFCH and signal.

* Method 2: When the receiving terminal feeds back the SL CSI to the transmitting terminal, whether the SL CSI is transmitted through the PSSCH or the PSFCH is signaled to the transmitting terminal through 1-bit SCI.

Method 1 is a method in which the transmitting terminal instructs the receiving terminal of the channel for the SL CSI to be received. In contrast, method 2 is a method in which the receiving terminal determines a channel to feed back SL CSI and informs the transmitting terminal of the channel. Compared to Method 1, Method 2 has an advantage that the UE performing the feedback can directly determine a channel that is attached to the feedback among the currently valid feedback channels.

Unlike the method in which the SL CSI is directly transmitted through a physical channel as described above, a method in which the SL CSI is transmitted through a sidelink MAC-CE may be considered. When SL CSI is transmitted through MAC-CE, a method of mapping SL CSI to a physical channel need not be defined. In other words, the CSI information may be included through the MAC-CE above the UE, and in the case of Mode1, the SL CSI may be transmitted through the PSSCH resource allocated by the base station, and in the case of the Mode2, the SL CSI may be transmitted through the PSSCH resource selected by the UE. However, unlike a method in which SL CSI is directly transmitted through a physical channel, CSI information is transmitted to a higher level of the terminal, mapped to the MAC-CE, and transmitted again through a physical channel, so that a delay may additionally occur in CSI reporting.

Unlike the channel state information framework in the Uu interface between base station terminals, in the channel state information framework of the NR sidelink system, difficulties may arise in the process of the transmitting terminal requesting the SL CSI report and the receiving terminal performing the SL CSI report. have. Specifically, in the case of Mode1, the UE may transmit SL CSI information to the PSSCH resource allocated from the base station (see SL CSI transmission channel method 1 or method 2). When the transmitting terminal requests the SL CSI report, but the receiving terminal does not receive the allocation of PSSCH resources from the base station in time, a problem of delaying the SL CSI report of the receiving terminal may occur. In Mode2, when the receiving terminal feeds back the SL CSI to the transmitting terminal, the receiving terminal directly determines the PSSCH resource for transmitting the SL CSI through Mode2 sensing and resource selection, and the transmitting terminal through Mode2 sensing and resource selection. A method of requesting feedback from SL CSI to the determined PSSCH resource may be considered. Even in Mode2, even when the receiving terminal feeds back the SL CSI to the transmitting terminal, the available PSSCH resources may not be allocated in time. To solve this problem, the following effective SL CSI window setting method can be considered.

How to set the effective SL CSI window

* Method 1: If the effective SL CSI window is set in the transmitting terminal and it is determined that it is difficult to receive the SL CSI feedback from the receiving terminal within the SL CSI window, it is determined that no feedback will come from the receiving terminal when the SL CSI request is not made or the SL CSI window is crossed. I can.

* Method 2: When the effective SL CSI window is set in the receiving terminal and the SL CSI window is passed, the SL CSI report is not reported to the transmitting terminal.

It has been described that the effective SL CSI window can be set in the report setting of the channel state information framework of the NR sidelink system. As described above, the effective SL CSI window is connected to the support pool and can be (pre-)configurated for each resource pool. It can also be set through Uu-RRC or PC5-RRC. Also, the SL CSI window may be set in units of slots. In addition, the SL CSI window can be set by reflecting the feedback delay requirement. Therefore, the term of the SL CSI window may be referred to as the term of latency bound for SL CSI reporting. Therefore, it should be noted that the terms of the SL CSI window may be named differently. As in Method 1 and Method 2, the SL CSI window may be separately set for the transmitting terminal and the receiving terminal, or the SL CSI window may be set in common for the transmitting terminal and the receiving terminal. In the method 1, when the transmitting terminal requests the feedback of the SL CSI to the PSSCH resource determined through Mode2 sensing and resource selection in Mode2, it can be determined whether the PSSCH resource is effective in receiving the SL CSI feedback by looking at the effective SL CSI window. have. For example, if a valid PSSCH resource does not satisfy the feedback delay, the SL CSI request may not be made. In addition, when the transmitting terminal sees the effective SL CSI window and the SL CSI window passes, it may be determined that feedback will not come from the receiving terminal. In the method 2, when the receiving terminal reports the effective SL CSI window, the PSSCH resource allocated from the base station in Mode1 or the PSSCH resource selected for transmitting the SL CSI through sensing and resource selection in Mode2 passes through the SL CSI window, and the feedback delay. If it is not satisfied, the terminal may not report the SL CSI to the transmitting terminal. When operating the effective SL CSI window as described above, it is possible to more effectively operate the SL CSI request and report in the sidelink. In addition, if both PSSCH and PSFCH are supported as a channel through which SL CSI is transmitted, and the receiving terminal can select the channel to report SL CSI to the transmitting terminal, the terminal reporting the SL CSI can transmit faster among the available PSSCH and PSFCH resources. You can select a channel and send it. In addition, when the receiving terminal reports SL CSI using the corresponding channel, the receiving terminal may inform the transmitting terminal of information on which channel has been selected and transmitted through SCI.

Hereinafter, a more detailed terminal operation for operating the proposed effective SL CSI window will be described through an example. In the example below, the term latency bound for SL CSI reporting is used instead of the term for the effective SL CSI window.

The latency bound for SL CSI reporting can be set by converting to a slot within the range of 3~20ms. Specifically, it may be set in the range of 3*2 ^μ to 20*2 ^μ slots in consideration of subcarrier spacing (SCS). Here, μ is an index corresponding to numerology and can be set to the following values according to SCS.

* SCS=15kHz, μ=0

* SCS=30kHz, μ=1

* SCS=60kHz, μ=2

* SCS=120kHz, μ=3

Next, the following can be considered as a method of setting the latency bound for SL CSI reporting.

* Method 1: The latency bound X is (pre-)configurated for each resource pool within the range of 3~20ms.

* Method 2: The terminal can select the latency bound X within the range of 3~20ms. Also, the selected latency bound can be set through PC5-RRC.

* Method 3: Y (3ms≤Y≤20ms) is (pre-)configuration for each resource pool. The terminal can select the latency bound X within the range of Y~20ms. Also, the selected latency bound can be set through PC5-RRC.

First, in Method 1, the setting of the latency bound X can be adjusted by the network. When Method 1 is applied, the UE in the resource pool must perform SL CSI reporting to satisfy the X value set in the resource pool.

Method 2 is a method in which the terminal directly selects the latency bound X. This can be selected as a terminal implementation. In this case, the UE may be directly selected by the UE performing SL CSI reporting, or may be selected by the UE triggering SL CSI report. If the corresponding terminal is a transmitting terminal triggering the SL CSI report, the X value selected by the transmitting terminal may be set through PC5-RRC. In other words, a corresponding setting value may be transferred between the transmitting terminal and the receiving terminal in the PC5-RRC set-up step. Then, the terminal performing SL CSI reporting must perform SL CSI reporting so that the latency bound is satisfied using a value set through PC5-RRC.

Method 3 is a combination of Method 1 and Method 2. In the case of Method 2, since the UE directly selects the latency bound X, if all UEs in the resource pool select a very low X value for fast SL CSI feedback, the degree of congestion in the resource pool may increase. Therefore, Method 3 is a method in which the setting of Y (3ms≤Y≤20m) can be adjusted by the network. Next, the terminal can select the latency bound X within the range of Y~20ms. Therefore, the terminal can select the latency bound X according to the Y value set by the network.

When the latency bound X for SL CSI reporting is determined through the above method, the UE must perform SL CSI reporting to satisfy this. For a method of allocating a resource that satisfies the latency bound X, refer to the Mode1 operation and the Mode2 operation proposed in the present invention. However, if the UE reporting the SL CSI does not allocate a resource that satisfies the latency bound X value after receiving the triggering for CSI report, the UE may not be expected to perform the SL CSI report. In other words, SL CSI may not be reported. However, when a resource satisfying the X value is allocated, the UE may perform SL CSI reporting through the proposed [SL CSI transport channel] or sidelink MAC-CE. In this case, the information included in the SL CSI may be CQI and RI information. The present invention is information included in SL CSI and is not limited to CQI and RI information.

As described above, when the SL CSI is transmitted on the PSSCH or PSFCH, the SL CSI report is considered a non-subband based aperiodic SL CSI report that is reported only for the frequency domain corresponding to the PSSCH transmitted by the transmitting terminal. In the case of a Uu interface between base station terminals, whether to use a wideband PMI/CQI that reports one PMI or CQI for the entire frequency band and transmits CSI-RS in all bands, or divides the frequency band into several subbands, CSI was reported by determining whether to use subband PMI/CQI reporting one PMI or CQI per subband, but the sidelink is communication between the terminal and the terminal, and as suggested above, the SL CSI-RS is transmitted in all bands. Rather, a non-subband based aperiodic SL CSI report is used because the transmitting terminal transmits the SL CSI-RS in the PSSCH only in the frequency domain in which the resource is allocated to the PSSCH.

As described above, the present invention considers aperiodic SL CSI transmission. SL CSI reporting may be enabled/disabled separately from triggering/activation of aperiodic SL CSI reporting. It has been described that enable/disable for SL CSI reporting can be set in the report setting of the channel state information framework of the NR sidelink system. In addition, note that SL CSI reporting can be triggered/activated only when SL CSI reporting is enabled. Various methods for triggering/activation of SL CSI reporting can be considered as follows.

SL CSI reporting triggering/activation method

* Method 1: When SL CSI reporting is enabled, SL CSI reporting is automatically triggered/activated.

* Method 2: SL CSI reporting is enabled and SL CSI reporting is triggered/activated by SCI.

* Method 3: SL CSI reporting is enabled and SL CSI reporting is triggered/activated by MAC CE.

* Method 4: When SL HARQ-ACK reporting is enabled and the receiving terminal transmits NACK to the transmitting terminal X (≥1) times, the SL CSI report is triggered/activated.

* Method 5: If the RSRP value reported by the receiving terminal to the transmitting terminal is lower than the threshold X, the SL CSI report is triggered/activated.

* Method 6: When SL CSI reporting is enabled and CSI-RS transmission is configured, SL CSI reporting is triggered/activated.

* Method 7: SL CSI reporting is triggered/activated when SL CSI reporting is enabled and the timer set by the receiving terminal ends.

First, Method 1, Method 3, Method 4, Method 5, and Method 7 are methods in which the transmitting terminal triggers/activates the SL CSI report to the receiving terminal without introducing additional signaling. Method 2, Method 3, and Method 6 are methods in which the transmitting terminal uses additional signaling to trigger/activate SL CSI report to the receiving terminal. Method 2 is a method using SCI, Method 3 is a method using MAC CE, and method 6 is an implicit method for triggering/activation of SL CSI reporting. In Method 6, it is a method of indirectly determining whether SL CSI report is triggered/activated according to whether or not CSI-RS transmission is set. The CSI-RS transmission setting is based on the resource setting of the channel state information framework of the NR sidelink system. It can be included in the configuration for SL CSI-RS in the resource set. In contrast, the CSI-RS transmission may be configured through SCI or MAC CE. Method 6 is a method in which SL CSI report is triggered/activated when SL CSI-RS transmission is configured and SL CSI-RS is transmitted. In addition, the SCI format for triggering/activating the SL CSI report in Method 2 may be designed in the same manner as the general SCI format or may be designed in different forms. In addition, as an extended form of Method 4, SL HARQ-ACK reporting is enabled in the sidelink groupcast, and SL CSI reporting is triggered/activated only for terminals that have transmitted NACK X (≥1) times among terminals in the group. have. In the case of Method 7, when SL CSI reporting is enabled and a timer set by a receiving terminal is ended, SL CSI reporting is triggered/activated. If the timer set by the receiving terminal is constant and restarts each time after SL CSI reporting, this may belong to the periodic SL CSI reporting method. However, if the timer set by the receiving terminal is not constantly set or does not restart every time after SL CSI reporting, an aperiodic SL CSI reporting method may be used.

Next, a method of feeding back CQI, CQI+RI, or CQI+RI+PMI as information on SL CSI will be described. When there is more than one information about SL CSI, there may be a dependency between SL CSI information. Specifically, when the UE feeds back CQI+RI, the CQI is calculated based on the determined RI (refer to the second embodiment below for an example different from this.) In the present invention, a report on CQI+RI is performed. It is assumed that CQI and RI are always reported together. When the UE feeds back CQI+RI+PMI, the CQI is calculated based on the reported or determined PMI and RI. Below, the generation method for SL CSI will be described in more detail through the definition of CQI in the sidelink and the definition of CSI reference resource. First, the CQI in the sidelink may be defined as follows.

SL CQI

As shown in FIG. 6-20, the UE corresponding to the receiving end in the sidelink derives each CQI value reported in slot n as in FIG. 6-60 as the highest CQI index that satisfies the following condition.

* One PSSCH TB transport block composed of a combination of a modulation scheme corresponding to the CQI index, a target code rate, and a transport block size may be received so as not to exceed the next transport block error probability. Here, the PSSCH TB transport block occupies a sidelink physical resource block or subchannels named as SL CSI reference resource.

** 0.1, if the cqi-Table in SL-CSI-ReportConfig indicates the following'table1' (Table 1) or'table2' (Table 2) in the upper layer setting

** 0.00001, if the cqi-Table in the SL-CSI-ReportConfig indicates the following'table3' (Table 3) as the upper layer setting

In the CQI definition, the highest CQI index may be selected in consideration of Channel Busy Ratio (CBR). A more specific method will be described in more detail through Example 3. When the target transport block error probability is set to 0.1, it is a case in which Table 1 ('table1') or Table 2 ('table2') is used. Table 1 ('table1') or Table 2 ('table2') is a CQI table designed in consideration of the target transport block error probability of 0.1. In the case of Table 1 ('table1'), modulation is considered up to QPSK, 16QAM, and 64QAM. In the case of Table 2 ('table2'), modulation is considered up to QPSK, 16QAM, 64QAM, and 256QAM. If up to 256QAM is supported in the sidelink, Table 1 ('table1') or Table 2 ('table2') can be set as described above, and a corresponding CQI table can be set and used according to whether or not to use 256QAM. However, when 256QAM is not supported in the sidelink, only Table 1 ('table1') can be supported to be settable. In contrast, Table 3 ('table3') is a CQI table designed in consideration of a target transport block error probability of 0.00001, and modulation is considered up to QPSK, 16QAM, and 64QAM. The reason why two target transport block error probabilities of 0.1 and 0.00001 are considered as described above is that service requirements may be different. The NR sidelink also defines PQI (PC5 5QIs) for various QoS requirements, and the PQI includes Default priority level, Packet delay budget, Packet error rate, Default maximum date burst volume, and Default averaging window. Here, the packet error rate can be set to various values between 10^-1 and 10^-5. As described above, it is possible to operate using two target transport block error probability settings of 1 and 0.00001, but to support more accurate QoS, it is also possible to support setting a more detailed target transport block error probability other than 1 and 0.00001. For example, when a target transport block error probability setting of 0.001 is additionally introduced, a corresponding CQI table may be additionally defined.

CQI index modulation code rate x 1024 efficiency 0 out of range One QPSK 78 0.1523 2 QPSK 120 0.2344 3 QPSK 193 0.3770 4 QPSK 308 0.6016 5 QPSK 449 0.8770 6 QPSK 602 1.1758 7 16QAM 378 1.4766 8 16QAM 490 1.9141 9 16QAM 616 2.4063 10 64QAM 466 2.7305 11 64QAM 567 3.3223 12 64QAM 666 3.9023 13 64QAM 772 4.5234 14 64QAM 873 5.1152 15 64QAM 948 5.5547

CQI index modulation code rate x 1024 efficiency 0 out of range One QPSK 78 0.1523 2 QPSK 193 0.3770 3 QPSK 449 0.8770 4 16QAM 378 1.4766 5 16QAM 490 1.9141 6 16QAM 616 2.4063 7 64QAM 466 2.7305 8 64QAM 567 3.3223 9 64QAM 666 3.9023 10 64QAM 772 4.5234 11 64QAM 873 5.1152 12 256QAM 711 5.5547 13 256QAM 797 6.2266 14 256QAM 885 6.9141 15 256QAM 948 7.4063

CQI index modulation code rate x 1024 efficiency 0 out of range One QPSK 30 0.0586 2 QPSK 50 0.0977 3 QPSK 78 0.1523 4 QPSK 120 0.2344 5 QPSK 193 0.3770 6 QPSK 308 0.6016 7 QPSK 449 0.8770 8 QPSK 602 1.1758 9 16QAM 378 1.4766 10 16QAM 490 1.9141 11 16QAM 616 2.4063 12 64QAM 466 2.7305 13 64QAM 567 3.3223 14 64QAM 666 3.9023 15 64QAM 772 4.5234

Next, the CSI reference resource in the sidelink can be defined as follows.

SL CSI reference resource definition

When the terminal corresponding to the receiving end in the side link as in FIG. 6-20 generates SL CSI information as in FIG. 6-50, the SL CSI reference resource may be defined as follows.

* In the frequency domain, the SL CSI reference resource is defined by a sidelink physical resource block or a group of subchannels corresponding to the band inducing SL CSI.

* In the time domain, the CSI reference resource (9-10) is defined as slot nn _CSIref when reporting of channel status information is made in _sidelink slot n (9-20). Refer to FIG. 9 for a related description.

** 비주기적 SL CSI 보고에 대해서 n_CSIref는

** For aperiodic SL CSI reporting, n _CSIref is

*** SL CSI 요청이 발송된 사이드링크 슬롯과 동일 슬롯에서 채널상태정보 리포트를 하도록 설정된 경우, n_CSIref는 CSI 요청이 발송된 사이드링크 슬롯을 가리키며,

*** When it is set to report channel status information in the same slot as the _sidelink slot from which the SL CSI request was sent, n _CSIref indicates the _sidelink slot from which the CSI request was sent,

*** 이외의 경우, n_CSIref는 단말이 CSI 계산을 위해 필요한 시간보다 크거나 같으며 n과 가장 가까운 사이드링크 슬롯에 대응되는 값일 수 있다.

In cases other than ***, n _CSIref may be greater than or equal to the time required for the UE to calculate CSI and may be a value corresponding to a _sidelink slot closest to n.

** 본 개시의 일 실시 예에 따르면, 단말은 채널상태정보 보고 시, 해당 채널상태정보 보고에 대응되는 CSI reference resource와 동일한 시점 혹은 이전 시점의 CSI-RS resource(9-30)를 기반으로 측정한 채널상태정보를 보고할 수 있다. 관련 동작은 NR 사이드링크 시스템의 채널상태정보 프레임워크의 CSI report setting에 measurement restriction에 대한 설정정보에 의해서 결정될 수 있다. measurement restriction을 하도록 설정된 경우에는 CSI reference resource와 동일한 시점의 CSI-RS resource만을 이용하여 채널 상태를 측정하고 measurement restriction이 설정되지 않은 경우에는 CSI reference resource와 동일한 시점과 이전 시점의 CSI-RS resource를 모두 이용하여 채널 측정을 수행할 수 있다.

** According to an embodiment of the present disclosure, when reporting the channel state information, the UE measures based on the CSI-RS resource (9-30) at the same time point as or prior to the CSI reference resource corresponding to the corresponding channel state information report One channel status information can be reported. The related operation may be determined by setting information for measurement restriction in the CSI report setting of the channel state information framework of the NR sidelink system. When the measurement restriction is set, the channel status is measured using only the CSI-RS resource at the same time as the CSI reference resource. If the measurement restriction is not set, all CSI-RS resources at the same time as the CSI reference resource and the previous time are used. Can be used to perform channel measurement.

When it is configured to report the CQI index in the SL CSI reference resource, the UE corresponding to the receiving end on the sidelink may assume some or all of the following for the purpose of inducing the CQI index.

* A OFDM symbol is used as a control channel.

* B OFDM symbols are used as AGC symbols.

* C OFDM symbols are used as GP.

* The number of PSSCH and DMRS symbols is D.

* The same SCS as the SL BWP is set for PSSCH reception.

* The reference resource uses the CP length and SCS set for PSSCH reception.

* No RE is used as SSB.

* The value of RV is 0.

* The EPRE of PSSCH and CSI-RS is the same.

* No RE is assigned to NZP CSI-RS or ZP CSI-RS.

* It is assumed that the number of front-loaded DMRS symbols is one and the number of additional DMRSs is a value set by the SCI or resource pool.

* It is assumed that the PSSCH symbol does not include the DMRS.

* PRB bundling size is assumed to be 2PRB.

* PSSCH transmission can be performed up to two transmission layers. In order to calculate the CQI index, the UE assumes that the PSSCH transmission of [0, v-1] corresponding to v layers is transmitted to the antenna port of [0,...,P-1] as shown in the following equation. .

는 PSSCH 심볼에 대한 vector를 나타낸다. 그리고 P는 SL CSI-RS 포트 수를 나타낸다. 만약 하나의 CSI-RS 포트가 설정되는 경우에 W(i)는 1이 된다. SL-CSI-ReportConfig의 reportQuantity가 'CQI-RI-PMI'로 설정된 경우 W(i)는 에 적용할 수 있는 보고된 PMI에 해당되는 precoding matrix가 된다. SL-CSI-ReportConfig의 reportQuantity가 'CQI' 또는 'CQI-RI'로 설정된 경우 W(i)는 layer 수 v에 의해 1/sqrt(v)로 스케일된 identity matrix가 된다. here

Denotes a vector for the PSSCH symbol. And P represents the number of SL CSI-RS ports. If one CSI-RS port is configured, W(i) is 1. When the reportQuantity of SL-CSI-ReportConfig is set to'CQI-RI-PMI', W(i) becomes a precoding matrix corresponding to the reported PMI applicable to. When the reportQuantity of SL-CSI-ReportConfig is set to'CQI'or'CQI-RI', W(i) becomes an identity matrix scaled to 1/sqrt(v) by the number of layers v.

In the above, the assumption about the use of time domain resources of the slot for measuring the sidelink CQI index may be performed as an example as follows. When it is configured to report the CQI index in the SL CSI reference resource, the UE corresponding to the receiving end in the sidelink assumes the following for the purpose of inducing the CQI index.

[Assumption set 1]

* The first two OFDM symbols in the slot are used as control channels.

* The number of PSSCH and DMRS symbols in a slot is 8

* One OFDM symbol is used as a GP.

* Two OFDM symbols are used as PSFCH.

* One OFDM symbol is used as a GP.

Alternatively, the following assumption set 2 could be applied.

[Assumption set 2]

* The first two OFDM symbols in the slot are used as control channels.

* The number of PSSCH and DMRS symbols in a slot is 11

* One OFDM symbol is used as a GP.

The assumption set 1 may be for a case where a resource occupied by the PSFCH exists in a slot, and the assumption set 2 may be for a case where a resource occupied by the PSFCH does not exist in the slot. Whether to apply the assumption used by the UE measuring and reporting CSI when generating CSI as the assumption set 1 or the assumption set 2 may be determined according to the resource pool setting, or in the bitfield of PC5-RRC or SCI. You can decide accordingly. Alternatively, it may be possible to determine according to the presence or absence of PSFCH resources in the slot in which the sidelink CSI-RS is transmitted. That is, if the PSFCH resource exists in the slot in which the CSI-RS is transmitted, the assumption set 1 is applied, and if the PSFCH resource does not exist in the slot in which the CSI-RS is transmitted, the assumption set 2 is applied.

As another example, the assumption about the use of time domain resources of the slot for measuring the sidelink CQI index is to generate CSI feedback information including the CQI index using the structure of the slot in which the actual sidelink CSI-RS is transmitted. How to do it is possible. Since this is always transmitted with the PSSCH when CSI-RS is transmitted on the sidelink, the CQI index, etc., is generated assuming that the actual mapping resources such as the number of symbols and frequency resources occupied by the PSSCH in the slot in which the CSI-RS is transmitted are utilized. It may be possible to do.

<First Example>

Embodiment 1 of the present invention proposes a method of performing sensing in a situation where periodic and aperiodic traffic coexist for UE autonomous resource allocation (Mode 2) in the sidelink of V2X and selecting a transmission resource through this. In addition, in Mode2, when the receiving terminal feeds back the SL CSI to the transmitting terminal, the receiving terminal directly determines the PSSCH resource for transmitting the SL CSI through Mode2 sensing and resource selection, and the transmitting terminal performs Mode2 sensing and resource selection. A method of feeding back the SL CSI to the PSSCH resource determined through may be considered. In Embodiment 1 of the present invention, a terminal operation for this will be described in more detail.

First, sensing may be defined as an operation of performing Sidelink Control Information (SCI) decoding for another terminal and an operation of performing sidelink measurement. The operation of performing SCI decoding for another terminal includes an operation of obtaining SCI information by the other terminal after successfully decoding the SCI. In addition, the transmission resource selection may be defined as an operation of determining a resource for sidelink transmission by using the sensing result. Depending on the state of the sidelink, a process of reselecting a transmission resource may be performed.

In the present invention, a Sensing window A and a Sensing window B are defined in order to effectively perform sensing in a situation where periodic and aperiodic traffic coexist.

8 is an example of a method of configuring Sensing window A and Sensing window B for sidelink UE autonomous resource allocation (Mode 2). When data to be transmitted is generated, the terminal performs sensing during a set sensing window period and may select a transmission resource based on the result.

As shown in FIG. 8, when triggering for selecting a transmission resource occurs in slot n (8-01), a sensing window A (8-02) may be defined as follows.

* Sensing window A can be defined as a slot section of [n-T0, n-1]. Here, T0 may be determined as a fixed value or may be determined to be settable.

** T0 가 고정된 값으로 결정되는 경우에 대한 일례로, 주기적인 트래픽에 대해서 T0=1000*2^μ으로 나타내어질 수 있다. 이와 달리, 비주기적인 트래픽에 대해서 T0=100*2^μ의 고정된 값이 설정될 수 있다. 상기 예시의 고정된 T0값은 고려되는 트래픽 특성에 따라 다른 값으로 변경될 수 있으며 주기적 및 비주기적 트래픽에 대해서 같은 값으로 고정될 수도 있다. 여기서 μ는 numerology에 해당하는 index이며 SCS(Subcarrier Spacing)에 따라 다음과 같은 값으로 설정된다.

** As an example of the case where T0 is determined to be a fixed value, it may be expressed as T0=1000*2 ^μ for periodic traffic. Alternatively, a fixed value of T0 = 100 * 2 ^μ may be set for aperiodic traffic. The fixed T0 value in the above example may be changed to a different value according to the traffic characteristics to be considered, and may be fixed to the same value for periodic and aperiodic traffic. Here, μ is an index corresponding to numerology and is set to the following values according to SCS (Subcarrier Spacing).

*** SCS=15kHz, μ=0

*** SCS=15kHz, μ=0

*** SCS=30kHz, μ=1

*** SCS=30kHz, μ=1

*** SCS=60kHz, μ=2

*** SCS=60kHz, μ=2

*** SCS=120kHz, μ=3

*** SCS=120kHz, μ=3

** T0 가 설정 가능하도록 결정되는 경우에 대해서 이에 대한 설정은 SL SIB (Sidelink System Information Block) 또는 단말 특정 상위 시그널링을 통해 지시될 수 있다. SL SIB을 통해 지시되는 경우, 해당 시스템 정보 중 자원 풀 정보 내에 해당 값이 설정될 수 있다. 자원 풀을 할당하는 정보는 많은 파라미터들로 구성될 수 있으며 그 중 T0에 해당하는 값이 포함될 수 있다. 자원 풀 정보 내에 T0 가 설정되는 경우 해당 자원 풀 안에서는 항상 일정한 T0 가 사용됨을 의미한다.

** For a case where T0 is determined to be configurable, the configuration may be indicated through SL SIB (Sidelink System Information Block) or UE-specific higher level signaling. When indicated through SL SIB, a corresponding value may be set in resource pool information among corresponding system information. The information for allocating a resource pool may consist of many parameters, and a value corresponding to T0 may be included among them. If T0 is set in the resource pool information, it means that a constant T0 is always used in the resource pool.

* In the sensing window A, SCI decoding and sidelink measurement for other terminals may be performed.

** Sensing window A 내에서 SCI를 성공적으로 복호한 후 획득한 SCI정보로부터 다른 단말에 대한 자원 할당 정보 및 패킷에 대한 QoS 정보를 획득할 수 있다. 여기서 자원할당 정보는 리소스에 대한 reservation interval이 포함될 수 있다. 또한 QoS 정보로는 latency, reliability, 전송되는 트래픽에 대한 minimum required communication range 및 data rate 요구사항 등에 따른 priority 정보일 수 있다. 또한 수신된 SCI로부터 다른 단말에 대한 위치정보를 획득할 수도 있다. 다른 단말의 위치 정보와 나의 위치정보로부터 TX-RX distance를 계산할 수 있다.

** It is possible to obtain resource allocation information for other terminals and QoS information for packets from the SCI information obtained after successfully decoding the SCI in the sensing window A. Here, the resource allocation information may include a reservation interval for a resource. In addition, QoS information may be priority information according to latency, reliability, minimum required communication range and data rate requirements for transmitted traffic. It is also possible to obtain location information for other terminals from the received SCI. The TX-RX distance can be calculated from the location information of other terminals and the location information of mine.

** Sensing window A 내에서 SCI를 성공적으로 복호한 후 획득한 SCI정보로부터 SL RSRP (Sidelink Reference Signal Received Power)를 측정할 수 있다. 여기서 SL RSRP는 SCI를 성공적으로 복호한 후 획득한 SCI정보로부터 이에 해당되는 PSSCH에 대한 DMRS에 대한 평균 수신 파워 (in [W])를 측정하여 얻을 수 있다. 또 다른 방법으로는 SCI를 포함하는 PSCCH에 대한 DMRS에 대한 평균 수신 파워 (in [W])를 측정하여 얻을 수도 있다.

** SL RSRP (Sidelink Reference Signal Received Power) can be measured from the SCI information obtained after successfully decoding the SCI within the sensing window A. Here, the SL RSRP can be obtained by measuring the average reception power (in [W]) for the DMRS for the corresponding PSSCH from the SCI information obtained after successfully decoding the SCI. Alternatively, it may be obtained by measuring the average reception power (in [W]) for the DMRS for the PSCCH including SCI.

** Sensing window A 내에서 SL RSSI (Sidelink Received Signal Strength Indicator)를 측정할 수 있다. 여기서 SL RSSI는 수신신호강도를 의미하며 수신 단말에서 수신되는 전력 (in [W])이 얼마인지 나타내며 사이드링크의 슬롯 안의 유효한 OFDM 심볼 위치들과 설정된 서브채널에 의해서 관찰된다.

** SL RSSI (Sidelink Received Signal Strength Indicator) can be measured within the sensing window A. Here, SL RSSI means the received signal strength and indicates how much power (in [W]) is received from the receiving terminal, and is observed by the effective OFDM symbol positions in the slot of the sidelink and the set subchannel.

Sensing window A can be used for the main purpose of determining resources for UE autonomous resource allocation (mode 2) through periodic sensing of traffic. If it is determined that it is not effective to allocate transmission resources to resources to be used by other terminals by grasping the periodic resource allocation information of other terminals through the SCI decoding and using sidelink measurement results such as SL RSRP or SL RSSI, the Resource selection window (8) -03), the resource may be excluded.

As illustrated in FIG. 8, when triggering for selecting a transmission resource occurs in slot n (8-01), the Resource selection window (8-03) may be defined as follows.

* The resource selection window can be defined as a slot section of [n+T1, n+T2]. Here, T1 and T2 may be determined to be fixed values or may be determined to be settable. Alternatively, T1 and T2 are determined in a fixed range, and the UE may set an appropriate value within the fixed range in consideration of implementation.

** T1와 T2가 고정된 범위로 결정되고 단말이 구현을 고려하여 고정된 범위 안에서 적절한 값을 설정하는 일 예로 T1 ≤4*2^μ 그리고 20*2^μ ≤T2≤100*2^μ의 범위에서 단말 구현으로 설정할 수 있다. 여기서 μ는 numerology에 해당하는 index이다.

** As an example in which T1 and T2 are determined as a fixed range and the terminal sets an appropriate value within a fixed range considering implementation, in the range of T1 ≤4*2 ^μ and 20*2 ^μ ≤T2≤100*2 ^μ It can be set by terminal implementation. Where μ is the index corresponding to numerology.

* The final transmission resource (8-05) may be selected in the Resource selection window by using the sensing result performed in the Sensing window A. As described above, if it is determined that it is not effective to allocate transmission resources to resources to be used by other terminals using SCI decoding and sidelink measurement results such as SL RSRP or SL RSSI in Sensing window A, the Resource selection window (8-03) ), the resource can be excluded.

If sensing is performed using only the sensing window A as shown in FIG. 8 and transmission resource selection is performed through this, the following transmission resource selection method may be used.

* Transmission resource selection method-1

** Step-1: Resource selection window(6-03)안에서 설정 받은 리소스 풀 정보를 바탕으로 자원 할당이 가능한 리소스 후보 수 Mtotal가 결정된다.

** Step-1: The number of resource candidates available for resource allocation, Mtotal, is determined based on the resource pool information set in the Resource selection window (6-03).

** Step-2: Sensing window A(6-02)에서의 센싱 결과를 이용하여 Resource selection window(6-03)내에서 다른 단말이 점유하여 사용이 효과적이지 않을 것으로 판단되는 리소스는 제외(exclusion)하고 자원 할당이 가능한 리소스 후보 중 X(≤Mtotal)개를 남겨놓는다.

** Step-2: Using the sensing result in the Sensing window A (6-02), excludes resources that are occupied by other terminals and are determined to be ineffective in use within the Resource selection window (6-03). And it leaves X (≤Mtotal) of resource candidates for which resource allocation is possible.

** Step-3: 단말의 상위 계층(higher layer)으로 X개의 자원으로 구성된 리소스 후보 리스트가 보고 되고, 단말 상위 계층에서 X개의 후보 중 최종 전송 자원을 랜덤 선택(8-05)한다.

** Step-3: A resource candidate list consisting of X resources is reported as a higher layer of the terminal, and a final transmission resource is randomly selected (8-05) from among the X candidates in the upper layer of the terminal.

Next, as shown in FIG. 8, when triggering for selecting a transmission resource occurs in slot n (8-01), the sensing window B (8-04) may be defined as follows.

* Sensing window B can be defined as a slot section of [n+T1', n+T2']. Here, T1' and T2' may be determined as fixed values or may be determined to be settable. Unlike this, T1' and T2' are determined as fixed ranges, and the UE may set an appropriate value within the fixed range in consideration of implementation. And when k indicates that the resource is the last selected slot, the sensing window B stops at the k slot, and the sensing window B at this time becomes [n+T1', k].

** T1'와 T2'는 Resource selection window (8-03)의 T1와 T2의 값과 각각 동일한 값을 같도록 설정될 수 도 있고 다른 값으로 설정될 수도 있다.

** T1' and T2' may be set to be the same as the values of T1 and T2 in the Resource selection window (8-03), respectively, or may be set to different values.

** 예를 들어, T1'=0으로 설정된 경우는 전송 자원을 선택하는 triggering 슬롯 n 부터 센싱이 수행됨을 의미한다.

** For example, when T1'=0 is set, it means that sensing is performed from triggering slot n for selecting a transmission resource.

** 설정된 T1'와 T2'의 값에 의해 Sensing window B는 하나의 슬롯 또는 하나 이상의 슬롯으로 설정될 수 있다.

** Sensing window B may be set to one slot or more than one slot by the set values of T1' and T2'.

* In the sensing window B, SCI decoding and sidelink measurement for other terminals may be performed.

** Sensing window B에서의 SCI decoding 및 사이드링크 측정(Sidelink measurement)을 수행하는 동작은 Sensing window A와 함께 운영될 경우에 Sensing window A가 슬롯 n 이후로 연장되는 것으로 해석될 수도 있다.

** The operation of performing SCI decoding and sidelink measurement in the sensing window B may be interpreted as extending after the slot n when the sensing window A is operated together.

** 전송 자원을 선택하는 triggering 슬롯 n을 기준으로 이후에 설정된 Sensing window B에서는 실제 전송 자원이 할당될 수 있는 슬롯에 대한 사이드링크 측정(Sidelink measurement)을 수행하는 동작으로 Sensing window A에서는 예측할 수 없는 비주기적 트래픽을 센싱하는 동작으로 해석할 수도 있다.

** In Sensing window B, which is later set based on triggering slot n for selecting a transmission resource, sidelink measurement is performed for the slot to which the actual transmission resource can be allocated, which cannot be predicted in Sensing window A. It can also be interpreted as an operation of sensing aperiodic traffic.

** Sensing window B을 통해서 센싱을 수행하는 것은 트래픽이 주기적인지 비주기적인지에 상관없이 매 슬롯에서 센싱되는 트래픽에 대해 센싱을 수행하는 동작으로 이해할 수 있다.

** Sensing through the sensing window B can be understood as an operation that senses the traffic sensed in every slot regardless of whether the traffic is periodic or aperiodic.

If sensing is performed using only the sensing window B in FIG. 8 and transmission resource selection is performed through this, the following transmission resource selection method may be used.

* Transmission resource selection method-2

** Step-1: Sensing window B(8-04)내의 해당 슬롯에서 센싱을 수행하여 해당 리소스가 idle (다른 단말에 의해 점유되지 않은 경우)한지 여부를 판단한다.

** Step-1: Sensing is performed in the corresponding slot in the sensing window B(8-04) to determine whether the resource is idle (if not occupied by another terminal).

*** 주파수상에서의 리소스의 할당 단위는 A개(≥1)의 서브채널이거나, 모든 서브채널로 정의될 수 있다. 주파수상에서의 리소스의 할당 단위에 따라서 해당 슬롯 내 자원 할당이 가능한 리소스 후보 수 Ntotal(≥1)가 결정될 수 있다.

*** A resource allocation unit on a frequency can be defined as A (≥1) subchannels or all subchannels. The number of resource candidates Ntotal (≥1) capable of allocating a resource in a corresponding slot may be determined according to an allocation unit of a resource on a frequency.

*** 센싱은 SCI decoding 및 사이드링크 측정(Sidelink measurement)을 통해 수행될 수 있다.

*** Sensing may be performed through SCI decoding and sidelink measurement.

** Step-2-1: 만약 상기 Step-1에서 센싱을 통해 해당 리소스가 idle로 판단되면 해당 슬롯 내 자원 할당이 가능한 리소스 후보 수 Ntotal(≥1) 중 최종 전송 자원(8-05)을 결정한다.

** Step-2-1: If the corresponding resource is determined to be idle through sensing in Step-1, the final transmission resource (8-05) is determined among the number of resource candidates Ntotal (≥1) that can allocate resources in the corresponding slot. do.

** Step-2-2: 만약 상기 Step-1에서 센싱을 통해 해당 리소스가 모두 busy (다른 단말에 의해 점유된 경우)로 판단되면 다음과 같은 동작을 선택할 수 있다.

** Step-2-2: If it is determined that all the resources are busy (when occupied by other terminals) through sensing in Step-1, the following operation can be selected.

*** 만약 다음 슬롯도 Sensing window B(8-04)로 설정된 경우 다음 슬롯으로 넘어가 Step-1을 수행한다.

*** If the next slot is also set to Sensing window B(8-04), it moves to the next slot and performs Step-1.

*** 만약 다음 슬롯이 Sensing window B(8-04)로 설정되지 않은 경우 다음과 같은 동작을 고려할 수 있다.

*** If the next slot is not set to Sensing window B (8-04), the following operation can be considered.

**** 현재 슬롯에서 QoS 요구사항에 의해 전송을 하여야 하는 경우, Energy detection 결과를 활용하여 최종 전송 자원(8-05)을 결정한다. QoS 정보로는 latency, reliability, 전송되는 트래픽에 대한 minimum required communication range 및 data rate 요구사항 등에 따른 priority정보 일수 있다.

**** If transmission is to be performed in accordance with the QoS requirements in the current slot, the final transmission resource (8-05) is determined using the energy detection result. The QoS information may be priority information according to latency, reliability, minimum required communication range and data rate requirements for transmitted traffic.

**** 그렇지 않은 경우, 현재 슬롯에서의 전송을 취소하고 Backoff 동작이 수행될 수 있다.

**** If not, the transmission in the current slot may be canceled and a backoff operation may be performed.

As defined through FIG. 8, the sensing window A and the sensing window B may be classified based on a time when triggering for selecting a transmission resource comes down. In more detail, a sensing period previously set based on a triggering slot n for selecting a transmission resource may be defined as a sensing window A, and a later set sensing period as a sensing window B.

If sensing is performed using both the Sensing window A and the Sensing window B in FIG. 8 and transmission resource selection is performed through this, the following transmission resource selection method may be used.

* Transmission resource selection method-3

** Step-1: Resource selection window(8-03)안에서 설정 받은 리소스 풀 정보를 바탕으로 자원 할당이 가능한 리소스 후보 수 Mtotal가 결정된다.

** Step-1: Based on the resource pool information set in the Resource selection window (8-03), the number of resource candidates available for resource allocation, Mtotal, is determined.

** Step-2: Sensing window A(8-02)에서의 센싱 결과를 이용하여 Resource selection window(8-03)내에서 다른 단말이 점유하여 사용이 효과적이지 않을 것으로 판단되는 리소스는 제외(exclusion)하고 자원 할당이 가능한 리소스 후보 중 X(≤Mtotal)개를 남겨놓는다.

** Step-2: Using the sensing result in the Sensing window A (8-02), excludes resources that are occupied by other terminals and are determined to be ineffective in use within the Resource selection window (8-03). And it leaves X (≤Mtotal) of resource candidates for which resource allocation is possible.

** Step-3: 단말 higher layer로 리소스 후보 리스트 X를 리포트하고 higher layer에서 X개의 후보 중 Y(≤X)개의 후보를 랜덤으로 down-selection한다.

** Step-3: Reports the resource candidate list X to the terminal higher layer, and randomly down-selects Y (≤X) candidates among the X candidates in the higher layer.

** Step-4-1: Sensing window B(8-04)가 Resource selection window(8-03)안에 포함되는 경우, 단말은 higher layer에서 결정된 Y개의 후보 중, Physical layer에서 Sensing window B(8-04)의 센싱 결과를 이용하여 전송 자원 선택 방법-2에 의해 최종 전송 자원(8-05)을 선택한다.

** Step-4-1: When the Sensing window B (8-04) is included in the Resource selection window (8-03), the UE selects the Sensing window B (8-04) in the physical layer among Y candidates determined in the higher layer. The final transmission resource (8-05) is selected according to the transmission resource selection method-2 using the sensing result of 04).

*** Sensing window B(8-04)가 Resource selection window(8-03)안에 포함되는 경우는 도8에서 [n+T1, k]의 구간에 해당한다. 이러한 조건은 T1와 T2 그리고 T1'와 T2'의 설정에 의해 결정될 수 있다.

*** When the sensing window B (8-04) is included in the Resource selection window (8-03), it corresponds to the section of [n+T1, k] in FIG. 8. This condition can be determined by the settings of T1 and T2 and T1' and T2'.

** Step-4-2: Sensing window B가 Resource selection window(8-03)에 포함되지 않는 경우, Physical layer에서 Sensing window B에서의 센싱 결과를 이용하여 전송 자원 선택 방법-2에 의해 최종 전송 자원(8-05)을 선택한다.

** Step-4-2: When the sensing window B is not included in the resource selection window (8-03), the final transmission resource by the transmission resource selection method-2 using the sensing result in the sensing window B in the physical layer Select (8-05).

*** Sensing window B(8-04)가 Resource selection window(8-03)안에 포함되는 않는 경우는 도8에서 [n+T1', n+T1-1]의 구간에 해당한다. 이러한 조건은 T1와 T2 그리고 T1'와 T2'의 설정에 의해 결정될 수 있다.

*** If the sensing window B (8-04) is not included in the resource selection window (8-03), it corresponds to the section of [n+T1', n+T1-1] in FIG. 8. This condition can be determined by the settings of T1 and T2 and T1' and T2'.

In the transmission resource selection method-3, the step of selecting Y candidates from a higher layer (Step-3) may be omitted, and the following method may be used.

* Transmission resource selection method-4

** Step-1: Resource selection window(8-03)안에서 설정 받은 리소스 풀 정보를 바탕으로 자원 할당이 가능한 리소스 후보 수 Mtotal가 결정된다.

** Step-1: Based on the resource pool information set in the Resource selection window (8-03), the number of resource candidates available for resource allocation, Mtotal, is determined.

** Step-2: Sensing window A(8-02)에서의 센싱 결과를 이용하여 Resource selection window(8-03)내에서 다른 단말이 점유하여 사용이 효과적이지 않을 것으로 판단되는 리소스는 제외(exclusion)하고 자원 할당이 가능한 리소스 후보 중 X(≤Mtotal)개를 남겨놓는다.

** Step-2: Using the sensing result in the Sensing window A (8-02), excludes resources that are occupied by other terminals and are determined to be ineffective in use within the Resource selection window (8-03). And it leaves X (≤Mtotal) of resource candidates for which resource allocation is possible.

** Step-3-1: Sensing window B(8-04)가 Resource selection window(8-03)안에 포함되는 경우, 단말은 X개의 후보 중, Physical layer에서 Sensing window B(8-04)의 센싱 결과를 이용하여 전송 자원 선택 방법-2에 의해 최종 전송 자원(8-05)을 선택한다.

** Step-3-1: When Sensing window B (8-04) is included in the Resource selection window (8-03), the UE senses the Sensing window B (8-04) in the physical layer among X candidates Using the result, the final transmission resource (8-05) is selected according to the transmission resource selection method-2.

*** Sensing window B(8-04)가 Resource selection window(8-03)안에 포함되는 경우는 도8에서 [n+T1, k]의 구간에 해당한다. 이러한 조건은 T1와 T2 그리고 T1'와 T2'의 설정에 의해 결정될 수 있다.

*** When the sensing window B (8-04) is included in the Resource selection window (8-03), it corresponds to the section of [n+T1, k] in FIG. 8. This condition can be determined by the settings of T1 and T2 and T1' and T2'.

** Step-3-2: Sensing window B가 Resource selection window(8-03)에 포함되지 않는 경우, Physical layer에서 Sensing window B에서의 센싱 결과를 이용하여 전송 자원 선택 방법-2에 의해 최종 전송 자원(8-05)을 선택한다.

** Step-3-2: If the sensing window B is not included in the resource selection window (8-03), the final transmission resource by the transmission resource selection method-2 using the sensing result in the sensing window B in the physical layer Select (8-05).

*** Sensing window B(8-04)가 Resource selection window(8-03)안에 포함되는 않는 경우는 도8에서 [n+T1', n+T1-1]의 구간에 해당한다. 이러한 조건은 T1와 T2 그리고 T1'와 T2'의 설정에 의해 결정될 수 있다.

*** If the sensing window B (8-04) is not included in the resource selection window (8-03), it corresponds to the section of [n+T1', n+T1-1] in FIG. 8. This condition can be determined by the settings of T1 and T2 and T1' and T2'.

When Sensing window A and Sensing window B are set at the same time, the final resource selection may be determined by the Resource selection window (8-03) and Sensing window B (8-04). In the proposed transmission resource selection method-3 or transmission resource selection method-4, the sensing window A and the sensing window B are set at the same time to perform sensing in a situation where periodic and aperiodic traffic coexist, and through this, the selection of transmission resources is optimized. That's how to do it.

The transmission resource selection method 1/2/3/4 may be operated by explicitly setting the base station. Specifically, it is connected to the support pool and can be (pre-)configurated for each resource pool. It may be indicated through SL SIB (Sidelink System Information Block) or UE-specific higher level signaling. When indicated through SL SIB, a corresponding value may be set in resource pool information among corresponding system information. When it is set through an upper layer, it can indicate which transmission resource selection method to use by instructing Uu-RRC or PC5-RRC.

The operation of selecting sensing and transmission resources in the UE autonomous resource allocation (mode 2) of the sidelink described above can be implemented in various ways. For example, when Sensing window A and Sensing window B are configured at the same time, the terminal always performs sensing for Sensing window A, and if triggering for selecting a transmission resource occurs in slot n, sensing window B is sensed. Can be implemented to select the final transmission resource. However, since the operation in which the terminal is always sensing the sensing window A can use the sensing result of the sensing window A at any time, it has an advantage in terms of latency to select a transmission resource, but it may be a disadvantage in terms of terminal energy consumption. . Therefore, as another method, when a traffic to be transmitted occurs, the terminal immediately senses the sensing window A and triggering to select the transmission resource is performed in slot n, and then sensing the sensing window B. Can be implemented to choose. The latter method has the advantage of minimizing the energy consumption of the terminal by performing sensing only when necessary, but it can be a disadvantage in terms of latency in selecting a transmission resource.

Previously, a method for a UE to perform sensing for UE autonomous resource allocation (Mode 2) in the sidelink of V2X and select a transmission resource through this was described. Next, a method of selecting a resource for CSI reporting when the receiving terminal measures the channel state in Mode2 and reports it to the transmitting terminal will be described. As described above, the CSI report may be transmitted through the PSSCH. At this time, a case in which only CSI information is included in the PSSCH is also considered. Additionally, a method in which CSI is transmitted through PSFCH resources may be considered. The Mode2 sensing and transmission resource selection method described above can be applied not only when selecting a PSSCH resource, but also when selecting a PSFCH resource. However, in the present invention, the Mode2 sensing and transmission resource selection method is used to select the PSSCH resource, and the PSFCH resource can be allocated to the PSFCH transmission resource in the resource pool as described above. Here, it is assumed that a PSFCH format capable of transmitting SL CSI is defined. Unlike the method of allocating PSSCH transmission resources, the UE may be configured with a PSSCH transmission resource having a period of N slots (pre-). In addition, the UE may perform CSI reporting in the configured PSSCH resource and the corresponding slot. When the receiving terminal measures the channel state in Mode2 and reports it to the transmitting terminal, the following method can be considered when using the PSSCH as a resource for CSI reporting.

How to perform CSI reporting through PSSCH in Mode2

* Method 1: The receiving terminal directly determines the PSSCH resource for transmitting the SL CSI through Mode2 sensing and resource selection.

* Method 2: The receiving terminal transmits SL CSI by using the PSSCH resource determined by the transmitting terminal through Mode2 sensing and resource selection.

Method 1 is a method in which the receiving terminal directly selects and transmits the PSSCH resource using the Mode2 sensing and resource selection method described above in order to transmit the SL CSI, and Method 2 is the method set by the transmitting terminal through Mode2 sensing and resource selection. This is a method for the receiving terminal to feed back the SL CSI to the PSSCH resource. For Method 2, the transmitting terminal must reserve one or more resources through Mode2 sensing and resource selection, and when the transmitting terminal triggers/activates the CSI report, the time and frequency of the resource to receive the CSI report among the resources reserved by the transmitting terminal The location can be indicated through SCI. When the frequency position of the transmission resource is fixedly configured to use all the assigned subchannels, the transmitting terminal can inform the receiving terminal only the time position of the resource to receive the CSI report.

<Example 1-1>

In Embodiment 1-1 of the present invention, for UE autonomous resource allocation (Mode 2) in the sidelink of V2X, another method of performing sensing in a situation where periodic and aperiodic traffic coexists and selecting a transmission resource through it is proposed. do. Note that there is a difference in detailed operation compared to the first embodiment. In addition, the following method can be applied even when the UE operating in Mode2 selects a resource for SL CSI reporting. Specifically, the upper bound T ₂ of the resource selection widow may be determined in the detailed operation below to satisfy the latency bound for SL CSI reporting.

10(a), 10(b), and 10(c) define sensing widows and resource selection widows required for a terminal to perform resource (re) selection and re-evaluation in Mode 2 according to an embodiment of the present disclosure. It is a drawing to do.

Specifically, in (a) of FIG. 10, triggering for resource (re-) selection is performed at time n, and sensing is continuously performed even after the (re-)selection triggering time n to re-evaluate (re-) An example in which triggering for evaluation) is performed at n'(n'>n) is shown.

Referring to (a) of FIG. 10, it may be assumed that triggering for resource (re) selection is performed at time n. The triggering condition for resource (re)selection may be the case that one of the following conditions is satisfied.

* When there is no configured sidelink grant, or

* When trying to transmit without segmenting a Radio link control (RLC) Service Data Unit (SDU), but the configured sidelink grant fails to provide resource allocation space for RCL SDU transmission, or

* When the currently configured sidelink grant does not satisfy the latency requirement for data in the logical channel, or

* When the resource pool is set up, or is reset by RRC, or

* When pre-emption is enabled in the resource pool and part of the resource reserved by pre-emption is released

In the case of the above-described pre-emption, whether enabling/disabling of pre-emption to a resource pool may be (pre-)configuration. If, when pre-emption is enabled in the resource pool, the operation of pre-emption of the resource by the terminal means an operation of releasing a part of the reserved resource after the terminal reserves the resource by performing sensing and resource selection. can do. Specifically, referring to (b) of FIG. 10, when a resource reserved by another UE by performing 1 ^st SCI decoding overlaps some of the resources reserved by the present UE (711), the priority of the other UE is the transmitting terminal If the priority is higher than the priority of the human UE, and the SL-RSRP for the overlapping resource is greater than the associated SL-RSRP threshold, the terminal may release the overlapping resource 711 for the resource that has already been reserved. At this time, reselection of a resource is triggered so that a new resource 712 may be reselected. At this time, the priority of the transmitting terminal may be information indicated by SCI. The application of pre-emption can only be applied to overlapped resources. The resource reselection procedure may be performed according to the following [resource (re)selection procedure]. For a more detailed description, refer to the following [Conditions for performing pre-emption].

Resource (re)selection triggering occurs first at time n, and after resource selection, before reservation for the selected resource is signaled to SCI, re-evaluation condition is satisfied at time n'(n'>n) If so, triggering for resource (re)selection may occur again. For a more detailed description, refer to the following [How to support re-evaluation triggering operation], [when the terminal triggers re-evaluation of the selected resource], and [Conditions to trigger re-evaluation].

는 사이드링크 자원 풀에 속한 슬롯의 셋으로 정의될 수 있다. 하기 <표 4>의 정의에 따르면 sensing window는 슬롯 n이전에 설정된 T₀(ms)가 자원 풀에 속한 logical slot으로 변환되어 설정된 구간을 의미할 수 있다.When triggering for resource (re)selection occurs at time n, the sensing window can be defined as [nT ₀ , nT _proc,0 ). Here, T ₀ is the starting point of the sensing window and may be (pre-)configurated as resource pool information. The T ₀ value that can be (pre-)configuration can be X=100ms or Y=1000ms. The present disclosure does not limit the values of X and Y set to T ₀ to specific values. In one embodiment X is a reservation interval may be a value T ₀ when the supported set to not more than Xms, Y may be a value T ₀ supported when the reservation interval is set to a value greater than Xms. For example, when the reservation interval is set to 1000 ms, the value of T ₀ may limit the setting to X = 100 ms. This is because when the reservation interval is set to a value greater than 100 ms, and the value of T ₀ is set to X = 100 ms, a signal transmitted in a period greater than 100 ms may not be sensed. In addition, T _proc,0 may be defined as a time required to process a sensing result, and a required T _proc,0 may vary according to a set T ₀ value. Specifically, when a long T ₀ value is set, a long T _proc,0 may be required. Conversely, when a short T ₀ value is set, a short T _proc,0 may be required. Accordingly, in an embodiment _{, the} value of T _proc,0 may be fixed to one value, but another value adjusted by the set T ₀ value may be (pre-)configurated as resource pool information. For example, when the value of T ₀ is set to X = 100 ms, it may be set to T _{proc, 0} = 0.1 ms. When the T ₀ value is set to Y=1000, it may be set to T _proc,0 =1ms. Alternatively, it may be fixed as T _proc,0 =1ms regardless of the set T ₀ value. Unlike this, since various SCS (Subcarrier Spacing) are supported in the NR sidelink _, a method of determining T _proc,0 according to the SCS may be considered. Specifically, when the SCS is set to {15, 30}kHz, T _proc,0 is defined as 1 slot, and when the SCS is set to {60, 120}kHz, T _proc,0 is one of {1, 2} slots. A method of (pre-)configuration as a value may be considered. In contrast, when the SCS is set to {15, 30, 60}kHz, T _proc,0 is defined as 1 slot, and when the SCS is set to {120}kHz, T _proc,0 is among {1, 2} slots. A method of (pre-)configuration with one value may be considered. Here, the reason why 1 slot can be set even when a high SCS is used is because the value of T ₀ is set to X=100 ms, so that even a high SCS can be processed with a short T _proc,0 . For example, the sensing window can be defined by T ₀ and T _proc,0 as follows. In the following, T ₀ may mean a (pre-)configuration of one of the above-described values of X or Y. In addition, T _proc,0 may mean a value set higher according to the SCS as described above. Also in the following

May be defined as a set of slots belonging to the sidelink resource pool. According to the definition of <Table 4> below, the sensing window may mean an interval set by converting T ₀ (ms) set before slot n into a logical slot belonging to a resource pool.

except for those in which its transmission occur, where

if slot n belongs to the set (

), otherwise slot

is the first slot after slot n belonging to the set (

) where

is defined above and

is from higher layer parameter t0_processing.The UE shall monitor slots

except for those in which its transmission occur, where

if slot n belongs to the set (

), otherwise slot

is the first slot after slot n belonging to the set (

) where

is defined above and

is from higher layer parameter t0_processing .

Next, when triggering for resource (re)selection is made at time n, the resource selection window may be determined as [n+T ₁ , n+T ₂ ]. Here, T ₁ may be selected as a terminal implementation for T ₁ ≤ T _proc,1 . T _proc,1 is the maximum reference value in which the processing time required to select a resource is considered, and this processing time may vary depending on the terminal implementation. For example, according to the SCS, values of Alt 1 to Alt 7 shown in Table 5 below may be used as the value of T _proc,1 . That is, <Table 5> shows the value of T _proc,1 set in units of slots.

μ Alt 1 Alt 2 Alt 3 Alt 4 Alt 5 Alt 6 Alt 7 0 4 4 2 2 2 3 3 One 8 4 4 4 4 3 6 2 16 6 8 6 6 4 12 3 32 8 16 8 8 5 18

<Table 5> in Alt 1 is when the value of T _{proc, 1} fixed to 4ms Alt 3 can mean a case where the value of T _{proc, 1} fixed to 2ms. In addition, Alt 7 may mean a case where the value of T _proc,1 is fixed to 3 ms. The remaining cases are examples of cases in which the value of T _proc,1 is set differently in units of slots according to the SCS. In the present invention, it is a value set to T _proc,1 and is not limited to the value presented above. Accordingly, T ₁ may be selected as a value less than or equal to T _proc,1 by the UE implementation. Here, T ₁ may be defined as a unit of a slot. In addition, when it is assumed that Nmax resources can be selected for one TB, the Nmax resources may include initial transmission and retransmission resources. In this case, the UE may select T ₂ within a range that satisfies the T ₂ ≤ Remaining Packet delay budget (PDB). And T ₂ can be selected from the range satisfying the T ₂ ≥T _2min. If T _2min > Remaining PDB, T _2min = Remaining PDB. In other words, T _2min ≤ T ₂ ≤ Remaining Packet delay budget (PDB). Here, T _2min is to prevent the terminal from selecting too small a value of T ₂ . Here, T _2min may be defined as a function of priority of the transmitting terminal. The priority of the transmitting terminal may be information indicated by SCI. In addition, the T _{2min value'T 2min} (priority)' according to the priority may be set in the upper layer. For example, T _2min can be selected from the following set. T _2min _set={1, 5, 10, 20}*2 ^μ . Here, μ is an index corresponding to numerology and may be set to the following values according to SCS (Subcarrier Spacing).

* SCS=15kHz, μ=0

* SCS=30kHz, μ=1

* SCS=60kHz, μ=2

* SCS=120kHz, μ=3

Next, an operation of performing re-evaluation by continuously performing sensing even after triggering for resource (re) selection is made at time n may be considered. If the resource (re) selection is triggered at time n, and after the transmission resource is selected, sensing is continuously performed and it is determined that the selected resource is not suitable for transmission, the resource already selected at time n'(n'>n) Triggering to change can be defined as re-evaluation. The operation of triggering the re-evaluation of the resource selected at the time n'(n'>n) after the time n when triggering for the resource (re)selection is performed by the terminal may be performed when the following conditions are satisfied.

* When the terminal does not reserve the resource selected by triggering for resource (re)selection

In this case, the reservation for the resource may be interpreted as an operation of transmitting information on the selected resource through 1 ^st SCI. Therefore, the condition may be defined before information on the selected resource is transmitted through SCI. In addition, the following method may be considered as a support method for an action triggering re-evaluation.

[How to support behavior triggering re-evaluation]

* Method 1: terminal implementation

* Method 2: default operation of the terminal

* Method 2: enabling/disabling can be (pre-)configuration with the resource pool.

Specifically, method 1 may refer to a method of supporting whether or not the terminal supports triggering re-evaluation for a resource selected by the terminal through implementation of the terminal. Therefore, whether or not to implement re-evaluation may vary depending on the terminal. Method 2 and Method 3 may refer to a method of specifying an operation for triggering re-evaluation for a resource selected by the UE. Method 2 is a method of specifying that the re-evaluation triggering operation must be performed, and Method 3 may be a method of allowing the re-evaluation triggering operation only in the resource pool enabled by enabling/disabling (pre-)configuration with a resource pool. If method 1 is used, since triggering of re-evaluation may be supported depending on whether or not it is implemented, there may be limitations in improving the performance of Mode 2 operation to avoid collisions for resource transmission. Therefore, it may be assumed that Method 2 or Method 3 is used in the present disclosure.

Referring to FIG. 10, the UE may perform triggering for re-evaluation only before slot mT ₃ for at least slot m 701, which is a transmission time of an already selected resource. At this time, the change of the selected resource through reevaluation may be limited to the resource already selected at the time point m. Here, T ₃ may be a processing time required for reselection. As a first method, a method of using the resource selection processing time T ₁ already selected according to the UE implementation as T ₃ as it is may be considered (T ₃ =T ₁ ). However, the re-evaluation process may require additional processing time for resource selection. Specifically, not only the time required for dropping the previously selected resource may be required, but also the time required to deal with it may be required in cases such as the case where the old resource and the new resource overlap. Therefore, a method of setting T ₃ =T _proc,1 may be considered. This is because T _proc,1 is the maximum reference value in which the processing time required to select a resource is considered, so if triggering for re-evaluation is performed before the corresponding value, it may be possible to change the selected resource to another resource. Alternatively, a method of setting T ₃ = T ₁ +X may be considered. Here, the value of X may be defined in ms or may be defined in units of slots. For example, when defined as a unit of a slot, it may be determined as X=1 slot. In the present disclosure, the value of X is not limited to the above-described example. Therefore, the following method may be considered for the timing of triggering re-evaluation of the resource selected by the terminal.

[When the terminal triggers re-evaluation of the selected resource]

* Method 1: terminal implementation

* Method 2: The terminal triggers re-evaluation in all slots n'(n'>n) before mT ₃ .

* Method 3: The terminal triggers re-evaluation in the last slot n'corresponding to before mT ₃ .

를 만족시키는 시점 중에서 단말 구현으로 선택될 수 있다. Specifically, method 1 may refer to a method of supporting a terminal implementation without specification of an operation for triggering re-evaluation for a resource selected by the terminal. For example, Method 1 can be defined as follows. In the following <Table 6>, it is assumed that T ₃ is set to T ₃ = T ₁ +1 slot as described above. Also, m may be defined as a slot in which the resource (re) selection triggering is performed at time n and the resource is selected. According to the definition below, Method 1 is

It may be selected as the terminal implementation from among the points of time satisfying.

where

slots and m is the corresponding slot that resource is selected by resource (re-)selection procedure.After resource (re-)selection is triggered in slot n by higher layer, the UE shall trigger resource re-evaluation in slot n'>n. The triggering moment n'for re-evaluation is up to UE implementation under

where

slots and m is the corresponding slot that resource is selected by resource (re-)selection procedure.

Method 2 or 3 is a method of specifying an operation for triggering re-evaluation for a resource selected by the UE. Method 2 is a method in which the UE triggers re-evaluation in all slots n'(n'>n) before mT ₃ Depending on the length of'-n, multiple re-evaluations can occur. However, method 3 is a method of triggering re-evaluation in the last one slot n'corresponding to the terminal before mT ₃ , and the disadvantage of method 2 can be solved. If method 1 is used, since triggering of re-evaluation may be supported depending on whether or not it is implemented, there may be limitations in improving the performance of Mode 2 operation to avoid collisions for resource transmission. Therefore, it may be assumed that Method 2 or Method 3 is used in the present disclosure. As shown in FIG. 10, when triggering for re-evaluation occurs at n'(n'>n), the sensing window for this is (n'- T ₀ , n'-T _{proc, 0} ). As such, the resource selection widow for this may be determined as [n'+T ₁ , n'+T ₂ ]. At this time, the value of T ₀ and T _{proc, 0} may be the same value as the value used when triggering for resource (re) selection is performed at time n. However, for T ₁ and T ₂ , the terminal may select the same value as at point n when triggering for resource selection by implementation, but other values may be selected.

Next, an operation in which the terminal performs sensing in the above-described sensing window will be described. First, sensing may be defined as an operation in which a transmitting terminal performs sidelink control information (SCI) decoding for another terminal and an operation in which sidelink measurement is performed. The operation of performing SCI decoding on another terminal may include an operation of obtaining SCI information of another terminal after successfully decoding the SCI. At this time, SCI is information corresponding to 1 ^st SCI and may be obtained through detection of PSCCH. 1 ^st SCI may include the following information related to resource allocation.

[Conditions triggering re-evaluation]

Next, the condition for triggering the re-evaluation of the terminal may be defined as shown in Table 7 below. According to the definition below, the previous resource (re)selection triggering occurs first at time n, and only for the first selected initial transmission resource after the resource is selected (resource before the reservation for the selected resource is signaled by SCI), if When the RSRP of the corresponding resource is greater than the RSRP threshold set in the current re-evaluation process, it is determined that the condition for re-evaluation is satisfied, and re-evaluation may be triggered. In other words, triggering for resource (re) selection may occur again at time n'(n'>n).

the RSRP measurement for a resource of the selected sidelink grant for the first new transmission opportunity from the previous (re-)selection procedure is higher than the RSRP threshold in the current re-evaluation procedure.

If re-evaluation is triggered according to the conditions of <Table 7>, the terminal may report a resource candidate selected by [resource (re)selection procedure] to a higher level. Referring to FIG. 10, the sensing window and resource selection window at this time may be determined based on a time point n'(n'>n). In addition, when'only the first selected initial transmission resource' is described in more detail above, when method 1 (Dynamic reservation) is applied with reference to the following [Mode 2 resource reservation method], the initial transmission resource for one TB It may correspond to a transmission resource. When the method 2 (Semi-persistent reservation) is applied, even when resources for a plurality of TBs are reserved, it may correspond to an initial transmission resource for transmitting TB for the first time.

[Conditions to perform pre-emption]

) 및 자원 예약 주기 정보(

)를 포함한 자원 예약 정보를 파악할 수 있다. 그리고 조건 b)에서 수신한 1^st stage SCI로부터 파악한 RSRP 측정값이 RSRP 임계값(

) 보다 클 수 있다. 여기서

는 Pre-emption을 결정하는 값으로 하기 [자원 (재)선택하는 절차]에서 설정되는 SL-RSRP 임계치와 독립적인 값으로 설정될 수 있다. 구체적으로, priority level에 따라서 SL RSRP 임계치 Th_a,b가 Th_priTX,PriRX로 설정될 수 있다. 여기서 PriTX는 전송 단말에 대한 priority이며, b는 수신된 1^st stage SCI로부터 파악된 다른 단말의 priority를 의미할 수 있다. 또한 RSRP 측정에 대한 상세는 하기 [L1 SL RSRP 측정 방법]을 참고한다. 다음으로 조건 c)는 1^st stage SCI 디코딩을 수행하여 다른 UE에 의해 예약된 자원이, 본 UE가 예약한 자원의 일부과 겹치는 경우에 대한 조건을 제시할 수 있다. Next, detailed examples of conditions under which the terminal performs pre-emption may be presented through <Table 8>. First, when pre-emption is enabled in the resource pool, if all of the conditions a), b), and c) are satisfied as shown in <Table 8> below, the terminal triggers pre-emption and reserves part of the resource. Release and release resources can be reselected. In Table 8 below, SCI format 0-1 may mean 1 ^st stage SCI. According to the following <Table 8>, in condition a), the terminal receives 1 ^st stage SCI and the priority information of other terminals (

) And resource reservation cycle information (

), and resource reservation information can be identified. And the RSRP measurement value determined from the 1 ^st stage SCI received in condition b) is the RSRP threshold (

) Can be greater than. here

Is a value for determining pre-emption and may be set as a value independent of the SL-RSRP threshold set in the following [resource (re)selection procedure]. Specifically, according to the priority level, the SL RSRP threshold Th _a,b may be set to Th _priTX,PriRX . Here, PriTX is a priority for a transmitting terminal, and b may mean a priority of another terminal identified from the received 1 ^st stage SCI. In addition, for details of the RSRP measurement, refer to the following [L1 SL RSRP measurement method]. Next, condition c) may present a condition for a case where a resource reserved by another UE by performing 1 ^st stage SCI decoding overlaps some of the resources reserved by the present UE.

, and "Resource reservation period" field, if present, and "Priority" field in the received SCI format 0-1 indicate the values

and

, respectively
b) the RSRP measurement performed for the received SCI format 0-1, is higher than

;
the SCI format received in slot

or the same SCI format which, if and only if the "Resource reservation period" field is present in the received SCI format 0-1, is assumed to be received in slot(s)

determines the set of resource blocks and slots which overlaps with a resource of the configured sidelink grant for transmission opportunity. Here,

is

converted to units of logical slots.If a resource pre-emption is enabled in resource pool, the UE shall trigger the pre-emption if it meets all the following conditions:
a) the UE receives an SCI format 0-1 in slot

, and "Resource reservation period" field, if present, and "Priority" field in the received SCI format 0-1 indicate the values

and

, respectively
b) the RSRP measurement performed for the received SCI format 0-1, is higher than

;
the SCI format received in slot

or the same SCI format which, if and only if the "Resource reservation period" field is present in the received SCI format 0-1, is assumed to be received in slot(s)

determines the set of resource blocks and slots which overlaps with a resource of the configured sidelink grant for transmission opportunity . Here,

is

converted to units of logical slots.

If the conditions in <Table 8> are satisfied and pre-emption is triggered, and part of the reserved resource is released and the released resource is reselected, the resource reselection method is described below [resource (re)selection procedure] Can be performed according to.

[Resource allocation information of the 1 ^st SCI]

* Priority (QoS value)

* PSSCH resource assignment (frequency/time resource for PSSCH)

* Resource reservation period (if enabled)

** Refer to Method 2 of [Mode 2 Resource Reservation Method] below.

* PSSCH DMRS pattern (if more than one patterns are (pre-)configured)

** When more than one PSSCH DMRS pattern is (pre-)configuration, the UE may select a PSSCH DMRS pattern and indicate this as SCI.

* Number of PSSCH DMRS port(s)

Sidelink measurement is to determine whether another terminal occupies a resource in the time and frequency resource that the transmitting terminal intends to transmit, and for this purpose, the following measurement methods may be considered in the sidelink. .

[L1 SL RSRP measurement method]

* PSCCH RSRP (Reference Signal Received Power): The average reception power (in [W]) for the DMRS included in the PSCCH can be measured.

* PSSCH RSRP (Reference Signal Received Power): Measures the average received power (in [W]) for the DMRS included in the PSSCH.

Specifically, the UE may measure the PSCCH RSRP by monitoring the DMRS region of the PSCCH associated with 1 ^st SCI. In addition, the UE may perform 1 ^st SCI decoding and determine PSSCH information connected thereto from 1 ^st SCI information and monitor the PSSCH DMRS region to measure the PSSCH RSRP. The PSCCH RSRP and PSSCH RSRP may be referred to as L1 SL RSRP. As resource pool information, one of PSCCH RSRP or PSSCH RSRP may be selected as L1 SL RSRP (pre-)configuration.

Next, a resource (re-) selection procedure of the terminal in the resource selection window described above will be described. Specifically, it can be defined as the following two steps.

[Procedure for resource (re)selection]

* Step 1: Operation of identifying candidate resources for resource selection in the resource selection window

* Step 2: Operation of selecting a resource for transmission from the identified resource candidate

First, step 1 is an operation to find a candidate resource for resource selection in the resource selection window. In this case, the resource candidate may define one resource candidate for PSSCH transmission as R _x,y in the Resource selection window 702 as shown in FIG. 10. A resource pool on time and frequency used for transmission and reception of a sidelink has been described with reference to FIG. 3. R _x,y represents one resource candidate composed of consecutive subchannels of x+j in a subchannel region set as a resource pool for slot t _y belonging to the resource pool. Here, j=0,...,L _subCH-1 and L _subCH is a subchannel length for resource allocation, and may be selected within a resource allocation range that is down as system information. The number of all resource candidates in the resource selection window 702 may be defined as A. Resource candidates judged that it is not effective to allocate PSSCH transmission resources to the results sensed in the sensing window 703 may be excluded, and B (≦A) of resource candidates for which resource allocation is possible may be left. Here, it may be determined as B=A*X/100. At this time, the value of X may be fixed to one value in the range of 0≦X≦100, or one of several X values may be (pre-)configuration in the resource pool. For example, it may be set to X=20.

A detailed process of selecting B candidates excluding resources determined to be ineffective to allocate PSSCH transmission resources from the sensed result in step 1 is as follows.

1. In the sensing window 703, monitoring is performed except for the slot in which the actual transmission occurs.

2. According to the defined priority level, the L1 SL RSRP threshold Th _a,b is set to Th _priTX,PriRX . Here, PriTX is the priority for the transmitting terminal, and b is the priority of another terminal identified from the received SCI.

3. In the Resource selection window 702, set the total number of resource candidates R _x,y to set S _A.

4. If the following conditions are satisfied, the UE excludes the corresponding resource candidates R _x,y from S _A.

A. There is a slot t _z that has not been monitored due to actual transmission in step 1, and a reserved resource connected to t _z exists in the Resource selection window due to the configured Resource reservation period. (Refer to Method 2 in [Mode 2 Resource Reservation Method] below), or

B. It is determined that the SCI is transmitted by unicast or groupcast by decoding the SCI, and there are resources reserved by the received SCI in the future.

5. When all of the following conditions are satisfied, the UE excludes the corresponding resource candidates R _x,y from S _A.

A. First, the terminal may obtain resource allocation information for another terminal from the SCI received at t _m in the sensing window 703 (refer to [1 ^st SCI resource allocation information]), and

B. L1 SL RSRP is measured (refer to the L1 SL RSRP measurement method above), and the corresponding value is greater than the set Th _{priTX, PriRX} values, and

C. Due to the configured Resource reservation period, there are resources reserved for t _m in the Resource selection window _, and there are resources that are expected to overlap with R _x,y of S _A in the future.

)는 사이드링크 자원 풀에 속한 슬롯의 셋으로 정의될 수 있다. <표 9>에서

는 Resource reservation period(P)가 설정된 경우에 P∈{1:99, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000}ms에 의해서 각각

∈{0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}의 값으로 순차적으로 매핑된 값일 수 있다. 또한

는 남아있는 PDB(Packet delay budget)이 슬롯 단위로 변환된 값일 수 있다. * In this case, the detailed operation for condition C can be described in <Table 9> below. In <Table 9> below, SCI format 0-1 may mean 1 ^st stage SCI. In addition (

) May be defined as a set of slots belonging to the sidelink resource pool. In <Table 9>

When the Resource reservation period (P) is set, P∈{1:99, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000}ms respectively

∈{0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10} may be sequentially mapped values . In addition

May be a value obtained by converting the remaining packet delay budget (PDB) in units of slots.

or the same SCI format which, if and only if the "Resource reservation period" field is present in the received SCI format 0-1, is assumed to be received in slot(s)

determines the set of resource blocks and slots which overlaps with

for q=1, 2, …, Q and

. Here,

is

converted to units of logical slots,

if

and

, where

if slot n belongs to the set (

), otherwise slot

is the first slot after slot n belonging to the set (

); otherwise

.

is remaining packet delay budget (in slots).the SCI format received in slot

or the same SCI format which, if and only if the "Resource reservation period" field is present in the received SCI format 0-1, is assumed to be received in slot(s)

determines the set of resource blocks and slots which overlaps with

for q =1, 2,… , Q and

. Here,

is

converted to units of logical slots,

if

and

, where

if slot n belongs to the set (

), otherwise slot

is the first slot after slot n belonging to the set (

); otherwise

.

is remaining packet delay budget (in slots).

6. If the number of resource candidates remaining in the SA is less than B, Th _priTX,PriRX values are increased by 3dB, and process 3 is repeated.

7. The above process is repeated until the number of resource candidates R _x,y in S _A becomes B.

When B candidates are selected through the above process, the set of resource candidates may be defined as S _B. The UE reports S _B to the higher level.

Next, step 2 of resource (re)selection is an operation of determining a transmission resource from the S _B reported by the UE to the upper level in step 1. A transmission resource may be randomly selected from among resource candidates in S _{B at} the upper level of the terminal. The UE randomly selects resources within S _B , thereby avoiding selection of the same resource between UEs. A case in which resource selection is made for only one MAC PDU (Protocol Data Unit) and a case in which a number of MAC PDUs are made through reservation interval period setting (refer to Method 2 of [Mode 2 Resource Reservation Method] below) are described separately. . Here, the MAC PDU may be a unit corresponding to one TB in the physical layer. The UE may select and reserve up to Nmax resources for one MAC PDU (see Method 1 of [Mode 2 Resource Reservation Method] below). That is, when Nmax is set to 3, the terminal can select up to three resources. Of course, when Nmax is set to 3, the terminal may select only one resource or select only two resources.

When resource selection is made for one MAC PDU, a detailed process of step 2 of (re) selecting a resource is as follows.

1. In the upper layer of the terminal, a transmission resource for one transmission opportunity may be randomly selected from among resource candidates in S _B.

If the terminal selects more than one (>1) resource, it may move to the detailed process 1) or process 2) below. Whether or not SL HARQ feedback enable/disable may be set through SLRB (Sidlink Radio Bearer).

If HARQ feedback is disabled (if the retransmission method is blind retransmission), the transmission opportunity(s) may be selected by the following detailed process 1).

1) One transmission opportunity may be selected from among the resource candidates in S _B reported to the upper layer of the terminal, and a transmission resource for another transmission opportunity may be randomly selected from the remaining resource candidates. Process 1) may be repeated in order to additionally select a transmission opportunity according to the number of resources selected by the UE.

In contrast, if HARQ feedback is enabled (when the retransmission method is HARQ feedback-based retransmission), the transmission opportunity(s) may be selected by the following detailed process 2).

2) Regarding HARQ feedback, the period of the resource for transmitting and receiving PSFCH (N), the offset value between the slots transmitting the PSFCH in the slot receiving the PSSCH (K), and the preparation time for PSSCH retransmission (HARQ ACK/ Transmission resources for other transmission opportunities may be selected in consideration of the time of receiving the NACK and decoding it). Therefore, the terminal must maintain a minimum time gap considering the above time for any two selected resources. Specifically, when HARQ feedback is enabled as shown in (c) of FIG. 10, the UE must select a transmission opportunity to maintain the above time gap. Process 2) may be repeated to select an additional transmission opportunity according to the number of resources selected by the terminal.

3) In the transmission opportunities selected in the above process 1) or 2), the transmission opportunity that comes first in time is used for initial transmission, and the transmission opportunity that comes later may be a transmission resource for sequential retransmission.

When the terminal selects more than one (>1) resource, the conditions shown in Table 9 below must be satisfied.

First, in <Table 10> below, it is necessary to select between any two resources selected for one TB by the range indicating the time gap between these two resources as 1 ^st stage SCI. That is, the time range of the allocated resource that can be indicated in the 1 ^st stage SCI may be W. W may be given as the number of logical slots in the resource pool. For example, W may be given as 32 slots, and in this case, when selecting a resource, it is necessary to satisfy the conditions shown in Table 10 below.

for j=0, 1, …,

have been selected for a set of transmission opportunities of PSSCH, a set of slots

for j=0, 1, …,

for another set of transmission opportunities of PSSCH shall meet the conditions

and

where

is the maximum number of transmission opportunities of PSSCH in a selected slot set. For any two selected slot sets, when a set of slots

for j= 0, 1,… ,

have been selected for a set of transmission opportunities of PSSCH, a set of slots

for j= 0, 1,… ,

for another set of transmission opportunities of PSSCH shall meet the conditions

and

where

is the maximum number of transmission opportunities of PSSCH in a selected slot set.

Next, as described in 2) above, the period of resources capable of transmitting and receiving PSFCH in relation to HARQ feedback (N), an offset value (K) between slots transmitting PSFCH in the slot receiving the PSSCH, and PSSCH retransmission For any two resources selected by the UE to select the transmission resource for another transmission opportunity in consideration of the preparation time for (including the time to receive and decode HARQ ACK/NACK), the above time is considered Conditions for maintaining the time gap can be defined as shown in <Table 11> below. The condition in which PSFCH transmission is enabled in the resource pool below may be treated the same as the condition in which HARQ feedback is enabled. In addition, MinTimeGapPSFCH below is a parameter corresponding to the offset value (K) between the slots transmitting the PSFCH in the slot receiving the PSSCH, and the periodPSFCHresource means a parameter corresponding to the period (N) of the resource capable of transmitting and receiving PSFCH. have.

between any two transmission opportunities of PSSCH where
- a is a time gap between PSSCH transmission and corresponding PSFCH reception in slots determined by high layer parameter of MinTimeGapPSFCH and periodPSFCHresource.
- b is a PSFCH processing plus PSSCH retransmission preparation time in slots determined by UE implementation.If PSFCH transmission in the resource pool is enabled, the UE shall ensure a minimum time gap

between any two transmission opportunities of PSSCH where
-a is a time gap between PSSCH transmission and corresponding PSFCH reception in slots determined by high layer parameter of MinTimeGapPSFCH and periodPSFCHresource.
-b is a PSFCH processing plus PSSCH retransmission preparation time in slots determined by UE implementation.

2. The selected transmission opportunity(s) may be the selected sidelink grant.

When the selected sidelink grant is available, that is, when MAC PDU transmission is possible, the process may move to step 3 below.

3. By using the selected sidelink grant, the UE can determine the time and frequency location at which the PSCCH and PSSCH are transmitted.

4. The selected sidelink grant may be the configured sidelink grant.

When resource selection is made for one MAC PDU, a method of (re) selecting and reserving a resource will be described in more detail through Method 1 of [Mode 2 Resource Reservation Method] below.

Next, a detailed process of step 2 of resource (re)selection when resource selection is made for a plurality of MAC PDUs is as follows.

The resource selection method for one MAC PDU is applied to the above, so that the selected transmission opportunity(s) may be the selected sidelink grant (see process 2 above). At this time, a set of transmission opportunities for a plurality of MAC PDUs may be selected by the number of reservations set at an interval indicated by the reservation interval period based on each transmission opportunity(s). Each set of transmission opportunities can be used for initial transmission and retransmission. These sets can be selected sidelink grants. Also, in this case, steps 3 and 4 described above may be performed. When resource selection is made for a plurality of MAC PDUs, a method of selecting a resource and reserving it will be described in more detail through Method 2 of [Mode 2 Resource Reservation Method] below.

Next, according to the above description, an operation for the terminal to reserve a transmission resource after selecting a resource in the resource selection window based on the sensing result in the sensing window will be described. The following two methods can be used as a method for the UE to reserve transmission resources in the sidelink.

[Mode 2 resource reservation method]

* Method 1 (Dynamic reservation): When a method in which resources are reserved by SCI associated with another TB is not used, the transmitting terminal reserves N≤Nmax resources for one TB and frequency-time resource allocation information for this Is delivered to the receiving terminal through 1 ^st SCI.

* Method 2 (Semi-persistent reservation): When a method in which resources are periodically reserved by SCI associated with another TB is used, the transmitting terminal is indicated by a higher level for N≦Nmax resources reserved by method 1 Resource reservations for a plurality of TBs can be made consecutively after a time point corresponding to the resource reservation period (P). At this time, the transmitting terminal transmits the information on the resource reservation period to the receiving terminal through 1 ^st SCI.

First, the method 1 may mean a method of dynamically reserving N≦Nmax resources for one TB.

11 shows an example of a method of reserving a time-frequency resource according to an embodiment of the present disclosure.

For example, FIG. 11 shows an example of a method of reserving one (801) or two (802) or three (803) time-frequency resources by the method 1 above. The N _max may be a set value, and for example, may be set to 2 or 3. That is, when N _max is set to 3, up to 3 resource allocation information may be transmitted in SCI. Of course, when N _max is set to 3, only one resource allocation information may be transmitted, or only two resource allocation information may be transmitted, or three resource allocation information may be transmitted. The range of frequency-time resources that can be allocated above may be given as W. That is, the time range of the allocated resource that can be indicated by the SCI may be W. W can be given as the number of slots. For example, W may be given as 32, which may mean that N _max number of resource allocation information can be delivered in the SCI within 32 slots. In the case of Method 1, the number of subchannels for N≦N _max resources reserved by Method 1 is constant, but the location of frequency resources for each resource may vary.

Next, method 2 may refer to a method of periodically reserving resources for a plurality of TBs. The following may be considered as a value corresponding to the resource reservation period (P). P∈{0, 1:99, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000}ms. Here, the indication of P=0 may mean that Method 2 is not used. In other words, it may indirectly mean that method 1 is used without periodically reserving resources. This is a method in which the transmitting terminal transmits the reservation period P to the receiving terminal through 1 ^st SCI.The set for the reservation period actually used in the resource pool is (pre-)configurated, and it is transmitted with 4 bits or less in 1 ^st SCI. I can. For example, when P∈{0, 100, 200, 300} is set as a set, this can be indicated using only 2 bits of SCI information. Therefore, the total number of bits for 1 ^st SCI indicated in the resource pool may vary according to the number of sets for the reservation period set in the resource pool. In addition, triggering for resource (re)selection and re-evaluation may not be performed by the terminal until the upper layer Cresel is set as a counter and the corresponding counter becomes 0, and resources are periodically reserved for the plurality of TBs. Can be transmitted.

11 also shows an example of a method of semi-persistent reservation of a resource according to a reservation period (P) according to Method 2. According to 804, a method in which one resource is selected and reserved by method 1, and a resource is periodically reserved by a reservation period (P) by method 2 is illustrated. In addition, according to 805, a method in which two resources are selected and reserved by method 1, and resources are periodically reserved by a reservation period P by method 2 is illustrated. In the case of Method 2, the location of the frequency resource selected by Method 1 and the number of allocated subchannels may have a constant reservation period (P).

<Second Example>

In Embodiment 2 of the present invention, a method of calculating and reporting CQI and RI using CSI information by a receiving terminal in the sidelink of V2X will be described. In the present invention, it is assumed that CQI and RI are always reported together with CQI and RI. As described above, when the UE feeds back CQI+RI, the CQI is calculated based on the determined RI. In this case, CQI and RI are fed back independently. For example, when PSSCH transmission is considered only up to two transmission layers, RI may be reported by determining whether the preferred rank is 1 or 2 as a result of channel estimation using only 1-bit information. However, when PSSCH transmission is considered up to 8 transmission layers, the number of bits required to report RI must be increased to 3 bits. Table 1/2/3 shows the 4bit CQI Table used in NR Uu. The same CQI table can be reused in the sidelink.

Alternatively, a method in which CQI and RI are jointly encoded and fed back may be considered. In this case, when CQI+RI is fed back, CQI and RI are determined simultaneously based on a table in which CQI and RI are jointly encoded, rather than calculated based on the determined RI. A table in which CQI and RI are jointly encoded can be used by designing and defining a table encoded with modulation, coding rate, and RI. However, in a simpler method, the existing CQI table is used as it is and the RI mapped to the CQI index is Can be (pre-)configuration. In more detail, the preconfiguration method is a method of pre-storing an RI value mapped to a CQI index in the terminal. Alternatively, an RI value mapped to a CQI index may be configured in an upper layer. When using the upper layer, the RI value mapped to the CQI index may be set in Uu-RRC or PC5-RRC. When a joint-encoded table of CQI and RI is supported, an RI value mapped to a CQI index may be included in the above-described report setting setting. When this method is used, the effort of designing a table in which modulation, coding rate, and RI are encoded together can be reduced, and the number of CSI feedback bits can be further saved compared to a method in which CQI and RI independently feed back.

<Third Example>

Embodiment 3 of the present invention proposes a method of generating and reporting SL CSI by reflecting Channel Busy Ratio (CBR) when reporting SL CSI. In the sidelink of V2X, the setting range of the transmission parameter may be determined depending on whether the corresponding channel is congested. This is a congestion control function in which a terminal determines whether to access a channel when the channel is congested, and sets a transmission parameter to increase a transmission success probability of the terminal when the terminal is connected. Accordingly, the UE measures the Channel Busy Ratio (CBR), and accordingly, the setting range of the transmission parameter may be determined. In addition, the reflection of CBR can be considered together when transmitting SL CSI. First of all, CBR can be defined as follows.

CBR

CBR (Channel Busy Ratio) measured in slot n is as follows.

* For PSSCH, the S-RSSI (Sidelink Received Signal Strength Indicator) measured in slot [n-100, n-1] by the UE in the resource pool is defined as the ratio of subchannels that exceed the (pre-)configured threshold.

** 여기서 슬롯 인덱스는 Physical 슬롯 인덱스에 기반한다.

** Here, the slot index is based on the physical slot index.

** S-RSSI는 수신신호강도를 의미하며 수신 단말에서 수신되는 전력 (in [W])이 얼마인지 나타내며 사이드링크의 슬롯안의 유효한 OFDM 심볼 위치들과 설정된 서브채널에 의해서 관찰된다.

** S-RSSI means the received signal strength and indicates how much power (in [W]) is received from the receiving terminal, and is observed by the effective OFDM symbol positions in the slot of the sidelink and the set subchannel.

It is possible to determine whether the corresponding channel is congested by the CBR value measured by the definition of the CBR. The measured CBR value can be mapped to the corresponding CBR level, and the setting range of the transmission parameter can be determined by the CBR level. Transmission parameters determined by the CBR level are transmission power (Max Tx power), CR (Channel Occupancy Ratio) limit, PSSCH MCS (Modulation and Coding Scheme), PSSCH RI (Rank Indicator), PSSCH RB (Resource Block) allocation range, PSSCH retransmission related information may be included. However, in the present invention, there is no restriction on other information that can be included in the transmission parameter by the CBR level. When the measured CBR level is high, it means a congested environment in which a terminal with many corresponding channels accesses and transmits, so it may be advantageous to set a range of transmission parameters in a direction that increases the transmission probability of the transmitting terminal. The setting range of the transmission parameter corresponding to the CBR level may be (Pre-)configuration. For example, it may be set in V2X SIB or Uu-RRC or PC5-RRC. Table 12 and Table 13 show examples of the Tx parameter set determined by the CBR level. Table 12 shows how to set the minimum and maximum setting ranges for the PSSCH MCS, PSSCH RI, PSSCH RB allocation range, and PSSCH retransmission related parameters.In the case of Table 13, the maximum can be set for all parameters. It shows how to set the range of values that are present.

Parameter Value Max Tx power max CR limit max PSSCH MCS range min max PSSCH RI range min max PSSCH RB range min max PSSCH retransmission range min max

Parameter Value Max Tx power max CR limit max Max PSSCH MCS max Max PSSCH RI max Max PSSCH RB max Max PSSCH retransmission max

As described above, the terminal corresponding to the transmitting end in the sidelink may perform a function of measuring CBR for congestion control and adjusting transmission parameters through it. Therefore, even when transmitting SL CSI, feedback of the SL CSI by the receiving terminal reflecting the CBR may be a necessary function for congestion control. When performing feedback on CQI or RI among SL CSI reports considered in the present invention, it is possible to calculate CQI or RI in consideration of CBR. Specifically, the following methods can be considered.

CSI reporting method considering CBR

* Method 1: CBR is measured by a receiving terminal corresponding to the receiving end, and a feedback index for CQI or RI is determined within a transmission parameter setting range determined according to the CBR measured by the receiving terminal.

* Method 2: The CBR information measured by the transmitting terminal corresponding to the transmitting end is transmitted to the receiving terminal, and the receiving terminal determines a feedback index for CQI or RI within a transmission parameter setting range determined according to the CBR.

* Method 3: When the receiving terminal corresponding to the receiving terminal can use both the CBR information from the transmitting terminal and the CBR measured by the receiving terminal, the CQI or RI within the transmission parameter setting range determined according to the CBR corresponding to min (CBR_tx, CBR_rx) Determine the feedback index for

Note that in the above method, the CBR measured by the transmitting terminal corresponding to the transmitting end and the CBR measured by the receiving terminal corresponding to the receiving end may have different values. Specifically, a distribution of terminals located around a transmitting terminal and a distribution of terminals located around a receiving terminal may be different. Method 1 is a method in which the receiving terminal directly measures CBR and applies it to CSI reporting. In the sidelink, since the receiving terminal can switch to the transmitting terminal at any time and operate, it can be a natural operation to continuously determine the channel congestion state through CBR measurement. Method 2 is a method in which a transmitting terminal signals CBR information to a receiving terminal and uses it to apply CSI reporting. Signaling for CBR information can be delivered through SCI. If two-step SCI is introduced, CBR information may be included in the second SCI. If 16 CBR levels are considered, 4bit information may be included in the SCI and transmitted to the receiving terminal. Method 3 is applicable when both the CBR information (CBR_tx) of the transmitting terminal and the CBR information (CBR_rx) measured by the receiving terminal are available by the receiving terminal. In this case, min (CBR_tx, CBR_rx) in consideration of the worst case This is a method applied to CSI reporting by using the corresponding CBR. As described above, since the transmittable PSSCH MCS and PSSCH RI may be determined according to the CBR level, the UE may report CSI in consideration of this. More specifically, according to the SL CQI definition, the UE selects a high CQI index so as not to exceed the target transport block error probability, but when CBR is considered together, the CQI index is the highest within the range and maximum value of the PSSCH MCS that can be transmitted according to the CBR level. It can be determined with a high CQI index. In addition, when generating and reporting CL CSI by reflecting CBR, it is necessary to satisfy the CR limit among the transmission parameters determined by the CBR according to the method 1/2/3. In this case, the UE must drop the transmission or use another method to satisfy the CR limit. Therefore, if it is difficult to satisfy the CR limit, the CL CSI report may not be reported. In addition, when it is difficult to satisfy the CR limit, not only data transmission but also the receiving terminal may not report CL CSI and HARQ.

Additionally, the receiving terminal corresponding to the receiving end may consider feeding back CBR information as SL CSI information to the transmitting terminal corresponding to the transmitting end. As described above, since the distribution of terminals located around the transmitting terminal and the distribution of terminals located around the receiving terminal may be different, the CBR measured by the transmitting terminal and the CBR measured by the receiving terminal may have different values. Therefore, when the transmitting terminal determines a transmission parameter using both the CBR information (CBR_tx) measured by the transmitting terminal and the CBR information (CBR_rx) of the receiving terminal, it may be more advantageous for congestion control. Specifically, when the CBR corresponding to min (CBR_tx, CBR_rx) is used in consideration of the worst case, better congestion control performance can be expected when transmission is performed with a parameter value within a corresponding transmission parameter range. Instead of the receiving terminal feeding back CBR information to the transmitting terminal, a method of feeding back CR information may also be considered. When the transmitting terminal uses both the CR limit (CR_tx) by the CBR measured by the transmitting terminal and the CL limit information (CR_rx) of the receiving terminal, it may be more effective in congestion control. Specifically, by using a CR limit corresponding to min (CR_tx, CR_rx) in consideration of the worst case, the transmitting terminal may drop the transmission or satisfy the CR limit by using another method.

In order to carry out the above embodiments of the present invention, a transmitting unit, a receiving unit, and a processing unit of the terminal and the base station are shown in FIGS. 12 and 13, respectively. In the above embodiment, while a vehicle terminal supporting vehicle-to-everything (V2X) exchanges information using a sidelink with another vehicle terminal and a pedestrian mobile terminal, the receiving terminal measures the channel state and A method of reporting to a transmitting terminal and an operation of the terminal are shown, and in order to perform this, the base station and the receiving unit, the processing unit, and the transmitting unit of the terminal must each operate according to the embodiment.

Specifically, FIG. 12 is a block diagram showing the internal structure of a terminal according to an embodiment of the present invention. As shown in FIG. 12, the terminal of the present invention may include a terminal receiving unit 1800, a terminal transmitting unit 1804, and a terminal processing unit 1802. The terminal receiving unit 1800 and the terminal collectively refer to the transmitting unit 1804, and may be referred to as a transmitting/receiving unit in the embodiment of the present invention. The transceiver may transmit and receive signals with the base station. The signal may include control information and data. To this end, the transceiver unit may include an RF transmitter that up-converts and amplifies a frequency of a transmitted signal, and an RF receiver that amplifies a received signal with low noise and down-converts a frequency. In addition, the transmitting/receiving unit may receive a signal through a wireless channel, output it to the terminal processing unit 1802, and transmit the signal output from the terminal processing unit 1802 through the wireless channel. The terminal processing unit 1802 may control a series of processes so that the terminal can operate according to the above-described embodiment of the present invention.

13 is a block diagram showing an internal structure of a base station according to an embodiment of the present invention. As shown in FIG. 13, the base station of the present invention may include a base station receiving unit 1901, a base station transmitting unit 1905, and a base station processing unit 1902. The base station receiving unit 1901 and the base station transmitting unit 1905 may be collectively referred to as a transmission/reception unit in an embodiment of the present invention. The transceiver may transmit and receive signals with the terminal. The signal may include control information and data. To this end, the transceiver unit may include an RF transmitter that up-converts and amplifies a frequency of a transmitted signal, and an RF receiver that amplifies a received signal with low noise and down-converts a frequency. In addition, the transmission/reception unit may receive a signal through a wireless channel, output it to the base station processing unit 1902, and transmit the signal output from the terminal processing unit 1902 through the wireless channel. The base station processing unit 1903 may control a series of processes so that the base station can operate according to the above-described embodiment of the present invention.

In the specific embodiments of the present invention described above, the constituent elements included in the invention are expressed in the singular or plural according to the presented specific embodiment. However, the singular or plural expression is selected appropriately for the situation presented for convenience of explanation, and the present invention is not limited to the singular or plural constituent elements, and even constituent elements expressed in plural are composed of the singular or singular. Even the expressed constituent elements may be composed of pluralities.

Meanwhile, although specific embodiments have been described in the detailed description of the present invention, various modifications may be made without departing from the scope of the present invention. For example, one or more of Examples 1 to 3 may be combined and performed. Therefore, the scope of the present invention is limited to the described embodiments and should not be determined, and should be determined by the scope of the claims and equivalents as well as the scope of the claims to be described later.

Claims (1)

In the control signal processing method in a wireless communication system,
Receiving a first control signal transmitted from a base station;
Processing the received first control signal; And
And transmitting a second control signal generated based on the processing to the base station.

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