KR20230044962A - Method for performing sidelink communication and apparatus thereof - Google Patents

Abstract

The present invention relates to a method for performing sidelink communication and a device thereof. Provided are a method for allowing a terminal to perform sidelink communication comprises the following steps of: transmitting sidelink control information including request information for requesting coordination information and instruction information indicating a resource type to be included in the coordination information to a different terminal; receiving the coordination information from the different terminal; and determining resources for performing sidelink communication based on at least one of the coordination information and resource sensing information, and a device thereof.

Description

Method for performing side link communication and apparatus thereof

This disclosure relates to techniques for performing sidelink communications.

Demands for large-capacity data processing, high-speed data processing, and various service requests using wireless terminals in vehicles, industrial sites, etc. are being generated. As such, there is a need for a high-speed, high-capacity communication system capable of processing various scenarios and large amounts of data, such as video, wireless data, and machine-type communication data, beyond simply voice-oriented services.

To this end, ITU-R discloses requirements for adopting the IMT-2020 international standard, and research on next-generation wireless communication technology to meet the requirements of IMT-2020 is in progress.

In particular, 3GPP is conducting research on the LTE-Advanced Pro Rel-15/16 standard and the New Radio Access Technology (NR) standard in parallel to satisfy the requirements of IMT-2020, which is referred to as 5G technology. plans to be approved as a next-generation wireless communication technology.

In 5G technology, it can be applied and utilized in autonomous vehicles. To this end, it is necessary to apply 5G technology to vehicle communication (Vehicle to everything, V2X), and high-speed transmission and reception is required while ensuring high reliability for increasing data for autonomous driving.

In addition, in order to satisfy driving scenarios of various autonomous vehicles such as platooning, not only unicast data transmission and reception using vehicle communication, but also multicast data transmission and reception must be guaranteed.

As such, when a plurality of terminals perform sidelink communication using various communication types, there is a risk of collision of radio resources for sidelink communication. In particular, in the case of a communication mode in which the base station does not explicitly schedule radio resources, the risk of collision of radio resources for sidelink communication due to congestion increases.

The present embodiments may provide a method and apparatus for performing sidelink communication.

In one aspect, in this embodiment, in a method for a terminal to perform sidelink communication, sidelink control information including request information for requesting adjustment information and indication information indicating a resource type to be included in the adjustment information is transmitted to another terminal. It provides a method including transmitting to, receiving adjustment information from another terminal, and determining a resource for performing sidelink communication based on at least one of the adjustment information and the resource sensing information.

In another aspect, the present embodiment provides, in a terminal performing sidelink communication, sidelink control information including request information for requesting adjustment information and indication information indicating a resource type to be included in the adjustment information to another terminal. A terminal device including a transmitter for transmission, a receiver for receiving adjustment information from other terminals, and a control unit for determining a resource for performing sidelink communication based on at least one of the adjustment information and resource sensing information.

According to the present embodiments, it is possible to provide a method and apparatus for performing sidelink communication.

1 is a diagram schematically illustrating the structure of an NR wireless communication system to which this embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a radio access technology to which this embodiment can be applied.
5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which this embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which this embodiment can be applied.
7 is a diagram for explaining CORESET.
8 is a diagram for explaining various scenarios for V2X communication.
9 is a diagram for explaining a communication operation using adjustment information according to an exemplary embodiment.
10 is a diagram for describing an operation of a terminal according to an exemplary embodiment.
11 is a diagram for explaining a configuration of a terminal according to an embodiment.

DETAILED DESCRIPTION Some embodiments of the present disclosure are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present embodiments, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present technical idea, the detailed description may be omitted. When "comprises", "has", "consists of", etc. mentioned in this specification is used, other parts may be added unless "only" is used. In the case where a component is expressed in the singular, it may include the case of including the plural unless otherwise explicitly stated.

Also, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present disclosure. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term.

In the description of the positional relationship of components, when it is described that two or more components are "connected", "coupled" or "connected", the two or more components are directly "connected", "coupled" or "connected". ", but it will be understood that two or more components and other components may be further "interposed" and "connected", "coupled" or "connected". Here, other components may be included in one or more of two or more components that are “connected”, “coupled” or “connected” to each other.

In the description of the temporal flow relationship related to components, operation methods, production methods, etc., for example, "after", "continued to", "after", "before", etc. Alternatively, when a flow sequence relationship is described, it may also include non-continuous cases unless “immediately” or “directly” is used.

On the other hand, when a numerical value or corresponding information (eg, level, etc.) for a component is mentioned, even if there is no separate explicit description, the numerical value or its corresponding information is not indicated by various factors (eg, process factors, internal or external shocks, noise, etc.) may be interpreted as including an error range that may occur.

A wireless communication system in the present specification refers to a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, or a core network.

The present embodiments disclosed below may be applied to wireless communication systems using various wireless access technologies. For example, the present embodiments include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and singlecarrier frequency division multiple access (SC-FDMA). Alternatively, it may be applied to various radio access technologies such as non-orthogonal multiple access (NOMA). In addition, the wireless access technology may mean not only a specific access technology, but also a communication technology for each generation established by various communication consultative organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA may be implemented as a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced datarates for GSM evolution (EDGE). OFDMA may be implemented with a wireless technology such as institute of electrical and electronic engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), and the like. IEEE 802.16m is an evolution of IEEE 802.16e, and provides backward compatibility with a system based on IEEE 802.16e. UTRA is part of the universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) that uses evolved-UMTSterrestrial radio access (E-UTRA). Adopt FDMA. As such, the present embodiments may be applied to currently disclosed or commercialized radio access technologies, and may also be applied to radio access technologies currently under development or to be developed in the future.

Meanwhile, a terminal in the present specification is a comprehensive concept meaning a device including a wireless communication module that communicates with a base station in a wireless communication system, and in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio) It should be interpreted as a concept that includes not only User Equipment (UE), but also Mobile Station (MS), User Terminal (UT), Subscriber Station (SS), and wireless device in GSM. In addition, the terminal may be a user portable device such as a smart phone depending on the type of use, or may mean a vehicle or a device including a wireless communication module in the vehicle in the V2X communication system. In addition, in the case of a machine type communication system, it may mean an MTC terminal, an M2M terminal, a URLLC terminal, etc. equipped with a communication module to perform machine type communication.

A base station or cell in this specification refers to an end that communicates with a terminal in terms of a network, and includes Node-B (Node-B), eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, site, various types of antennas, base transceiver system (BTS), access point, point (e.g. transmission point, reception point, transmission/reception point), relay node ), mega cell, macro cell, micro cell, pico cell, femto cell, remote radio head (RRH), radio unit (RU), and small cell. Also, a cell may mean including a bandwidth part (BWP) in the frequency domain. For example, the serving cell may mean the activation BWP of the terminal.

Since there is a base station controlling one or more cells in the various cells listed above, the base station can be interpreted in two meanings. 1) In relation to the radio area, it may be a device itself that provides a mega cell, macro cell, micro cell, pico cell, femto cell, or small cell, or 2) it may indicate the radio area itself. In 1), all devices providing a predetermined radio area are controlled by the same entity or all devices interacting to form a radio area cooperatively are directed to the base station. Points, transmission/reception points, transmission points, reception points, etc., according to the configuration method of the radio area, become an example of a base station. In 2), the radio area itself in which signals are received or transmitted may be indicated to the base station from the viewpoint of the user terminal or the neighboring base station.

In this specification, a cell refers to a component carrier having coverage of a signal transmitted from a transmission/reception point or a coverage of a signal transmitted from a transmission/reception point (transmission point or transmission/reception point), and the transmission/reception point itself. can

Uplink (UL, or uplink) means a method of transmitting and receiving data from a terminal to a base station, and downlink (DL, or downlink) means a method of transmitting and receiving data from a base station to a terminal do. Downlink may mean communication or a communication path from multiple transmission/reception points to a terminal, and uplink may mean communication or communication path from a terminal to multiple transmission/reception points. In this case, in the downlink, the transmitter may be a part of a multi-transmission/reception point, and the receiver may be a part of a terminal. Also, in uplink, a transmitter may be a part of a terminal, and a receiver may be a part of a multi-transmission/reception point.

In uplink and downlink, control information is transmitted and received through control channels such as a physical downlink control channel (PDCCH) and a physical uplink control channel (PUCCH), and a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH). Data is transmitted and received by configuring the same data channel. Hereinafter, the situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is expressed in the form of 'transmitting and receiving PUCCH, PUSCH, PDCCH, and PDSCH'. do.

For clarity of explanation, 3GPP LTE/LTE-A/NR (New RAT) communication system is mainly described in the following technical idea, but the technical features are not limited to the corresponding communication system.

3GPP develops 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology after research on 4G (4th-Generation) communication technology. Specifically, 3GPP develops new NR communication technology separate from LTE-A pro and 4G communication technology, which has improved LTE-Advanced technology to meet the requirements of ITU-R as 5G communication technology. Both LTE-A pro and NR refer to 5G communication technology. Hereinafter, 5G communication technology will be described focusing on NR when a specific communication technology is not specified.

Operating scenarios in NR defined various operating scenarios by adding consideration to satellites, automobiles, and new verticals in the existing 4G LTE scenarios. It is deployed in the range to support mMTC (Massive Machine Communication) scenarios that require low data rates and asynchronous access, and URLLC (Ultra Reliability and Low Latency) scenarios that require high responsiveness and reliability and can support high-speed mobility. .

In order to satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, low latency technology, mmWave support technology, and forward compatible technology are applied. In particular, the NR system proposes various technical changes in terms of flexibility in order to provide forward compatibility. The main technical features of NR are described below with reference to the drawings.

<NR System General>

1 is a diagram schematically showing the structure of an NR system to which this embodiment can be applied.

Referring to FIG. 1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and NG-RAN controls the user plane (SDAP / PDCP / RLC / MAC / PHY) and UE (User Equipment) It consists of gNB and ng-eNB providing plane (RRC) protocol termination. The gNB mutual or the gNB and ng-eNB are interconnected through the Xn interface. gNB and ng-eNB are each connected to 5GC through NG interface. 5GC may include an Access and Mobility Management Function (AMF) in charge of a control plane such as terminal access and mobility control functions, and a User Plane Function (UPF) in charge of a control function for user data. NR includes support for both frequency bands below 6 GHz (FR1, Frequency Range 1) and above 6 GHz frequency band (FR2, Frequency Range 2).

gNB means a base station that provides NR user plane and control plane protocol termination to a terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal. The base station described in this specification should be understood as encompassing gNB and ng-eNB, and may be used to refer to gNB or ng-eNB separately as needed.

<NR wave form, numerology and frame structure>

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with multiple input multiple output (MIMO) and has the advantage of using a low-complexity receiver with high frequency efficiency.

On the other hand, in NR, since the requirements for data rate, latency, coverage, etc. are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through a frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing radio resources based on a plurality of different numerologies has been proposed.

값이 2의 지수 값으로 사용되어 지수적으로 변경된다.Specifically, the NR transmission numerology is determined based on sub-carrier spacing and cyclic prefix (CP), and based on 15 kHz as shown in Table 1 below

The value is used as the exponent value of 2 and changes exponentially.

subcarrier spacing Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the numerology of NR can be classified into five types according to the subcarrier spacing. This is different from the fact that the subcarrier interval of LTE, which is one of the 4G communication technologies, is fixed at 15 kHz. Specifically, in NR, subcarrier intervals used for data transmission are 15, 30, 60, and 120 khz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 12, and 240 khz. In addition, the extended CP is applied only to the 60khz subcarrier interval. Meanwhile, a frame structure in NR is defined as a frame having a length of 10 ms composed of 10 subframes having the same length of 1 ms. One frame may be divided into half frames of 5 ms, and each half frame includes 5 subframes. In the case of a 15 kHz subcarrier interval, one subframe consists of one slot, and each slot consists of 14 OFDM symbols.

2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.

Referring to FIG. 2, a slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length of the slot in the time domain may vary according to the subcarrier interval. For example, in the case of a numerology having a 15 khz subcarrier interval, a slot is 1 ms long and has the same length as the subframe. In contrast, in the case of numerology having a 30 kHz subcarrier interval, a slot is composed of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, subframes and frames are defined with a fixed time length, and slots are defined by the number of symbols, and the time length may vary according to subcarrier intervals.

Meanwhile, NR defines a basic unit of scheduling as a slot, and introduces a mini-slot (or sub-slot or non-slot based schedule) to reduce transmission delay in a radio section. When a wide subcarrier interval is used, the length of one slot is shortened in inverse proportion to a transmission delay in a radio section. Mini-slots (or sub-slots) are for efficient support of URLLC scenarios and can be scheduled in units of 2, 4, or 7 symbols.

Also, unlike LTE, NR defines uplink and downlink resource allocation at the symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of directly transmitting HARQ ACK/NACK within a transmission slot has been defined, and this slot structure is named and described as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in 3GPP Rel-15. In addition, a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols of a slot are set to uplink, and a slot structure in which downlink symbols and uplink symbols are combined are supported. NR also supports that data transmissions are distributed and scheduled over one or more slots. Therefore, the base station can inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station may indicate the slot format by indicating the index of the table configured through UE-specific RRC signaling using SFI, dynamically indicating through DCI (Downlink Control Information), or static or static through RRC. It can also be given quasi-statically.

<NR physical resources>

Regarding physical resources in NR, antenna ports, resource grids, resource elements, resource blocks, bandwidth parts, etc. are considered do.

An antenna port is defined such that the channel on which a symbol on an antenna port is carried can be inferred from the channel on which other symbols on the same antenna port are carried. Two antenna ports are quasi co-located or QC/QCL (quasi co-located or quasi co-location). Here, the wide range characteristics include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.

Referring to FIG. 3 , since NR supports a plurality of numerologies in the same carrier, a resource grid may exist according to each numerology. Also, resource grids may exist according to antenna ports, subcarrier intervals, and transmission directions.

A resource block consists of 12 subcarriers and is defined only in the frequency domain. Also, a resource element is composed of one OFDM symbol and one subcarrier. Accordingly, as shown in FIG. 3, the size of one resource block may vary according to the subcarrier interval. In addition, in NR, “Point A”, which serves as a common reference point for the resource block grid, and common resource blocks and virtual resource blocks are defined.

4 is a diagram for explaining a bandwidth part supported by a radio access technology to which this embodiment can be applied.

In NR, unlike LTE where the carrier bandwidth is fixed at 20Mhz, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in NR, as shown in FIG. 4, a bandwidth part (BWP) can be designated and used by a UE within a carrier bandwidth. In addition, the bandwidth part is associated with one numerology, is composed of a subset of consecutive common resource blocks, and can be dynamically activated according to time. Up to four bandwidth parts each of uplink and downlink are configured in the terminal, and data is transmitted and received using the active bandwidth part at a given time.

In the case of paired spectrum, the uplink and downlink bandwidth parts are set independently, and in the case of unpaired spectrum, to prevent unnecessary frequency re-tuning between downlink and uplink operations. For this purpose, the bandwidth parts of downlink and uplink are paired to share a center frequency.

<NR initial connection>

In NR, a UE accesses a base station and performs a cell search and random access procedure to perform communication.

Cell search is a procedure in which a UE synchronizes with a cell of a corresponding base station using a synchronization signal block (SSB) transmitted by the base station, acquires a physical layer cell ID, and obtains system information.

5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which this embodiment can be applied.

Referring to FIG. 5, the SSB consists of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

The UE receives the SSB by monitoring the SSB in the time and frequency domains.

SSB can be transmitted up to 64 times in 5 ms. A plurality of SSBs are transmitted in different transmission beams within 5 ms, and the UE performs detection assuming that SSBs are transmitted every 20 ms period based on one specific beam used for transmission. The number of beams usable for SSB transmission within 5ms may increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted below 3 GHz, SSBs can be transmitted using up to 8 different beams in a frequency band of 3 to 6 GHz, and up to 64 different beams in a frequency band of 6 GHz or higher.

Two SSBs are included in one slot, and the start symbol and the number of repetitions within the slot are determined according to the subcarrier interval as follows.

On the other hand, SSB is not transmitted at the center frequency of the carrier bandwidth, unlike SS of conventional LTE. That is, the SSB can be transmitted even in a place other than the center of the system band, and a plurality of SSBs can be transmitted in the frequency domain when wideband operation is supported. Accordingly, the UE monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are the center frequency location information of the channel for initial access, are newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster, so it can support fast SSB search of the terminal. can

The UE may acquire the MIB through the PBCH of the SSB. MIB (Master Information Block) includes minimum information for the terminal to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, the PBCH includes information about the position of the first DM-RS symbol in the time domain, information for monitoring SIB1 by the UE (eg, SIB1 numerology information, information related to SIB1 CORESET, search space information, PDCCH related parameter information, etc.), offset information between the common resource block and the SSB (the location of the absolute SSB within the carrier is transmitted through SIB1), and the like. Here, the SIB1 numerology information is equally applied to some messages used in the random access procedure for accessing the base station after the UE completes the cell search procedure. For example, the numerical information of SIB1 may be applied to at least one of messages 1 to 4 for a random access procedure.

The aforementioned RMSI may mean System Information Block 1 (SIB1), and SIB1 is periodically (eg, 160 ms) broadcast in a cell. SIB1 includes information necessary for the terminal to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the terminal to receive SIB1, it needs to receive numerology information used for SIB1 transmission and CORESET (Control Resource Set) information used for SIB1 scheduling through the PBCH. The UE checks scheduling information for SIB1 using the SI-RNTI in CORESET, and acquires SIB1 on PDSCH according to the scheduling information. The remaining SIBs except for SIB1 may be transmitted periodically or may be transmitted according to the request of the terminal.

6 is a diagram for explaining a random access procedure in a radio access technology to which this embodiment can be applied.

Referring to FIG. 6, when cell search is completed, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted through PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH composed of contiguous radio resources in a periodically repeated specific slot. In general, when a UE initially accesses a cell, a contention-based random access procedure is performed, and when random access is performed for beam failure recovery (BFR), a non-contention-based random access procedure is performed.

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), UL Grant (uplink radio resource), temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to indicate to which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a random access-radio network temporary identifier (RA-RNTI).

Upon receiving a valid random access response, the terminal processes information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies TAC and stores the temporary C-RNTI. In addition, data stored in the buffer of the terminal or newly generated data is transmitted to the base station using the UL grant. In this case, information capable of identifying the terminal must be included.

Finally, the terminal receives a downlink message for contention resolution.

<NR CORESET>

The downlink control channel in NR is transmitted in a CORESET (Control Resource Set) having a length of 1 to 3 symbols, and transmits up/down scheduling information, SFI (Slot Format Index), TPC (Transmit Power Control) information, etc. .

In this way, NR introduced the concept of CORESET to secure the flexibility of the system. A control resource set (CORESET) means a time-frequency resource for a downlink control signal. The UE may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. A Quasi CoLocation (QCL) assumption for each CORESET is set, which is used for the purpose of notifying the characteristics of the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by the conventional QCL.

7 is a diagram for explaining CORESET.

Referring to FIG. 7 , a CORESET may exist in various forms within a carrier bandwidth within one slot, and a CORESET may consist of up to three OFDM symbols in the time domain. In addition, CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration to allow additional configuration and system information to be received from the network. After establishing a connection with the base station, the terminal may receive and configure one or more CORESET information through RRC signaling.

In this specification, a frequency, frame, subframe, resource, resource block, region, band, subband, control channel, data channel, synchronization signal, various reference signals, various signals, or various messages related to NR (New Radio) can be interpreted in various meanings used in the past or currently used or in the future.

<side link>

In the existing LTE system, a radio channel and radio protocol were designed for direct communication (ie, side link) between devices to provide direct communication between devices and V2X (especially V2V) services.

Regarding the sidelink, S-PSS/S-SSS, which is a synchronization signal for synchronization between a wireless sidelink transmitter and a receiver, and PSBCH (Physical Sidelink Broadcasting Channel) for transmitting and receiving a related sidelink MIB (Master Information Block) have been defined. , In addition, PSDCH (Physical Sidelink Discovery channel) for transmission and reception of discovery information, PSCCH (Physical Sidelink Control Channel) for transmission and reception of SCI (Sidelink Control Information), and PSSCH (Physical Sidelink Shared Channel) for transmission and reception of sidelink data have been designed. .

In addition, in order to allocate radio resources for the sidelink, a technology has been developed that is divided into mode 1 in which a base station allocates radio resources and mode 2 in which a terminal selects and allocates radio resources from a radio resource pool. In addition, additional technological evolution was required in the LTE system to satisfy the V2X scenario.

In this environment, 3GPP derived 27 service scenarios related to vehicle recognition in Rel-14 and determined major performance requirements according to road conditions. In addition, in the recent Rel-15, 25 more advanced service scenarios such as platooning, advanced driving, and long-distance vehicle sensors were derived and six performance requirements were determined.

In order to satisfy these performance requirements, technology development has been conducted to improve the performance of sidelink technology developed based on conventional D2D communication to meet the requirements of V2X. In particular, in order to apply to C-V2X (Cellular-V2X), a technology that improves the physical layer design of the sidelink to be suitable for a high-speed environment, a resource allocation technology, and a synchronization technology can be selected as major research technologies.

Sidelinks described below may be understood as encompassing links used for D2D communication developed after 3GPP Rel-12, V2X communication after Rel-14, and NR V2X after Rel-15. In addition, each channel term, synchronization term, resource term, etc. is described with the same terms regardless of D2D communication requirements and V2X Rel-14 and 15 requirements. However, for convenience of understanding, if necessary, the sidelink for D2D communication in Rel-12/13 will be described focusing on the difference between sidelinks that satisfy V2X scenario requirements. Therefore, the terminology related to sidelinks described below is merely a description of D2D communication/V2X communication/C-V2X communication for convenience of comparison and understanding, and is not limitedly applied to a specific scenario.

<Resource Allocation>

8 is a diagram for explaining various scenarios for V2X communication.

Referring to FIG. 8, a V2X terminal (denoted as a vehicle, but can be set in various ways such as a user terminal) may be located within the coverage of a base station (eNB or gNB or ng-eNB) or outside the coverage of the base station. For example, communication may be performed between terminals within the coverage of the base station (UE N-1, UE G-1, and UE X), or between a terminal within the coverage of the base station and a terminal outside the coverage (ex, UE N-1, UE N-1). 2) may perform communication. Alternatively, communication may be performed between terminals outside the coverage of the base station (eg, UE G-1 and UE G-2).

In these various scenarios, allocation of radio resources for communication is required in order for a corresponding terminal to perform communication using a sidelink, and allocation of radio resources is largely classified into a base station handling allocation and a method of selecting and allocating radio resources by the terminal itself.

Specifically, in the sidelink, resource allocation by the UE includes a method in which the base station intervenes in resource selection and management (Mode 1) and a method in which the UE directly selects resources (Mode 2). In Mode 1, the base station schedules a scheduling assignment (SA) pool resource region and a DATA pool resource region allocated thereto to the transmitting terminal.

Meanwhile, resource pools may be subdivided into several types. First, it can be classified according to the contents of sidelink signals transmitted in each resource pool. For example, the contents of sidelink signals can be differentiated, and separate resource pools can be configured for each. As the contents of the sidelink signal, there may be a scheduling assignment (SA), a sidelink data channel, and a discovery channel.

The SA provides information such as MCS (modulation and coding scheme), MIMO transmission method, and TA (timing advance) required for demodulation of other data channels and the location of resources used by the transmitting terminal for transmission of the following sidelink data channel. It may be a signal containing This signal can also be multiplexed and transmitted together with sidelink data on the same resource unit. In this case, the SA resource pool may mean a resource pool in which SA is multiplexed with sidelink data and transmitted.

On the other hand, the FDM method applied to V2X communication can reduce the delay time in which data resources are allocated after SA resource allocation. For example, a non-adjacent method of separating a control channel resource and a data channel resource in one subframe in the time domain and an adjacent method of successively allocating a control channel and a data channel in one subframe are considered.

Meanwhile, when SA is multiplexed and transmitted along with sidelink data on the same resource unit, only sidelink data channels excluding SA information may be transmitted in a resource pool for sidelink data channels. In other words, resource elements used to transmit SA information on individual resource units in the SA resource pool can still be used to transmit sidelink data in the sidelink data channel resource pool. The discovery channel may be a resource pool for a message in which a transmitting terminal transmits information such as its own ID so that a neighboring terminal can discover itself. Even when the contents of sidelink signals are the same, different resource pools may be used according to transmission/reception properties of sidelink signals.

For example, even if it is the same sidelink data channel or discovery message, the method of determining the transmission timing of the sidelink signal (for example, whether it is transmitted at the time of reception of the synchronization reference signal or transmitted by applying a certain TA) or resource allocation method (For example, whether the base station assigns individual signal transmission resources to individual transmission terminals or whether individual transmission terminals select individual signal transmission resources within the pool), signal format (eg, each sidelink signal is assigned to one sub Resource pools may be divided into different resource pools according to the number of symbols occupied in a frame or the number of subframes used for transmission of one sidelink signal), signal strength from a base station, transmit power strength of a sidelink terminal, and the like.

<sync signal>

As described above, in the case of a sidelink communication terminal, it is likely to be located outside the base station coverage. Even in this case, communication using the side link must be performed. To this end, the problem of acquiring synchronization by a terminal located outside the base station coverage is important.

Hereinafter, based on the above description, a method for synchronizing time and frequency in sidelink communication, particularly in communication between vehicles, between vehicles and other terminals, and between vehicles and an infrastructure network, will be described.

D2D communication uses a sidelink synchronization signal (SLSS), which is a synchronization signal transmitted from a base station, for time synchronization between terminals. In C-V2X, a satellite system (GNSS: Global Navigation Satellite System) can be additionally considered to improve synchronization performance. However, priority may be given to synchronization establishment or the base station may indicate priority information. For example, in determining its own transmission synchronization, a UE selects a synchronization signal directly transmitted by a base station with the highest priority, and if it is located outside the coverage of the base station, it preferentially synchronizes with SLSS transmitted by a UE within the coverage of the base station. it will fit

On the other hand, since a wireless terminal installed in a vehicle or a terminal mounted in a vehicle has relatively less problems with battery consumption and can use satellite signals such as GPS for navigation purposes, time or frequency synchronization between terminals is set using satellite signals. can be used to Here, the satellite signals may include GNSS signals such as Global Positioning System (GLONAS), GALILEO, and BEIDOU in addition to the exemplified Global Positioning System (GPS).

Meanwhile, sidelink synchronization signals may include a primary synchronization signal (S-PSS, Sidelink Primary synchronization signal) and a secondary synchronization signal (S-SSS, Sidelink Secondary synchronization signal). The S-PSS may have a Zadoff-chu sequence of a predetermined length or a similar/modified/repeated structure to the PSS. Also, unlike the DL PSS, other Zadoff Chu root indices (eg, 26 and 37) may be used. The S-SSS may have a similar/modified/repeated structure to the M-sequence or SSS. If the terminals are synchronized from the base station, the SRN becomes the base station, and the S-SS (Sidelink synchronization signal) becomes the PSS / SSS.

Unlike DL PSS/SSS, S-PSS/S-SSS follows the UL subcarrier mapping scheme. PSBCH (Physical Sidelink broadcast channel) is the basic system information that the terminal needs to know first before transmitting and receiving sidelink signals (eg, information related to S-SS, duplex mode (Duplex Mode, DM), TDD UL / DL configuration , resource pool related information, type of application related to S-SS, subframe offset, broadcast information, etc.) may be transmitted. The PSBCH may be transmitted on the same subframe as the S-SS or on a subsequent subframe. DMRS can be used for demodulation of PSBCH. The S-SS and the PSBCH may be described by describing the S-SSB (Sidelink synchronization signal block).

SRN may be a node transmitting S-SS and PSBCH. The S-SS may be in the form of a specific sequence, and the PSBCH may be in the form of a sequence representing specific information or a code word after undergoing predetermined channel coding. Here, the SRN may be a base station or a specific sidelink terminal. In the case of partial network coverage or out of coverage, the UE may become an SRN.

In addition, the S-SS may be relayed for sidelink communication with an out of coverage terminal as needed and may be relayed through multiple hops. In the following description, relaying a synchronization signal is a concept that includes not only relaying a synchronization signal of a base station directly, but also transmitting a sidelink synchronization signal in a separate format according to a synchronization signal reception time. In this way, by relaying the sidelink synchronization signal, the in-coverage terminal and the out-of-coverage terminal can perform direct communication.

<NR Sidelink>

As described above, unlike V2X based on the LTE system, there is a demand for NR-based V2X technology to satisfy complex requirements such as autonomous driving.

In the case of NR V2X, it is intended to provide flexible V2X services in more diverse environments by applying the frame structure, numerology, and channel transmission and reception procedures of NR. To this end, development of technologies such as resource sharing technology between a base station and a terminal, sidelink carrier aggregation (CA) technology, partial sensing technology for a pedestrian terminal, and sTTI is required.

In NR V2X, it is decided to support unicast and group cast as well as broadcast used in LTE V2X. At this time, it was decided to use the target group ID for group cast and unicast, but whether to use the source ID will be discussed later.

In addition, as it is decided to support HARQ for QoS, it is also decided to include an HARQ process ID in the control information. In LTE HARQ, PUCCH for HARQ was transmitted 4 subframes after downlink transmission, but in NR HARQ, the feedback timing is, for example, in DCI format 1_0 or 1_1 PUCCH resource indicator (PUCCH resource indicator) or HARQ feedback for PDSCH PUCCH resources and feedback timing may be indicated by a timing indicator (PDSCH-to-HARQ feedback timing indicator).

In LTE V2X, separate HARQ ACK/NACK information was not transmitted to reduce system overhead, and for data transmission safety, the transmitting terminal was allowed to retransmit data once according to its selection. However, NR V2X can transmit HARQ ACK / NACK information in terms of data transmission stability, and in this case, overhead can be reduced by bundling and transmitting the corresponding information.

That is, when the transmitting terminal UE1 transmits three pieces of data to the receiving terminal UE2 and the receiving terminal generates HARQ ACK/NACK information for this, it may be bundled and transmitted through the PSCCH.

Meanwhile, in FR1 for the frequency domain below 3 GHz, it was decided to discuss 15 kHz, 30 kHz, 60 kHz, and 120 kHz as SCS (Subcarrier spacing) candidates. In addition, 30 kHz, 60 kHz, 120 kHz, and 240 kHz were discussed as candidates for subcarrier spacing (SCS) for FR2 in the frequency region exceeding 3 GHz. In NR V2X, mini-slots (eg, 2/4/7 symbols) smaller than 14 symbols may be supported as a minimum scheduling unit.

As RS candidates, DM-RS, PT-RS, CSI-RS, SRS, and AGC training signals were discussed.

Sidelink UL SPS

In general, UL transmission using SPS may cause some delay when the gap between user data generation and configured SPS resources is large. Therefore, when SPS is used for delay-sensitive traffic such as sidelink communication, the SPS scheduling interval must be small enough to support the delay requirements.

However, a smaller SPS scheduling interval may result in more overhead since the UE may not fully utilize the configured SPS resources. Therefore, the gap between user data generation and the configured SPS resources must be small and the SPS scheduling interval must be suitable to satisfy the delay requirements. Currently, there is no mechanism to support this feature.

A UE may receive SPS configuration for one or more specific logical channels. The UE may receive the SPS configuration for a specific logical channel through system information, an RRC connection establishment message, an RRC connection reconfiguration message, or an RRC connection release message.

When data is available for a specific logical channel(s), the UE may request SPS activation from the base station and then perform UL transmission using the configured SPS resources according to the SPS activation command received from the base station. The UE may transmit an SPS activation request to the base station through a physical uplink control channel (PUCCH), a MAC control element (CE), or an RRC message. That is, the UE may transmit an SPS activation request to the base station using control resources used for requesting SPS activation. The control resource may be a PUCCH resource, a random access resource, or a new UL control channel resource. In addition, the UE may transmit an SPS activation request to the base station, eg, during RRC connection (re-) establishment, during handover, after handover, or in RRC_CONNECTED.

Since the UE actively requests SPS activation from the base station when there is UL data to be transmitted, the gap between the generation of UL data and configured SPS resources can be reduced.

For example, the UE receives SPS configuration information including three SPS configurations from the base station. If there is UL data to be transmitted in the upper layer, the UE transmits an SPS request message to the base station through a MAC CE, for example. The base station sends an acknowledgment message (Ack message) for one of the three SPS configurations. The UE transmits UL data in a specific resource, for example, a 1sec period according to the corresponding SPS configuration.

On the other hand, if there is UL data to be transmitted in a higher layer at a specific time point, the UE transmits an SPS request message to the base station again through MAC CE, for example. The base station sends an acknowledgment message (Ack message) for the other one of the three SPS configurations. The UE transmits UL data with a specific resource, for example, a 100sec period according to the corresponding SPS configuration.

On the other hand, S-SS id_net is a set of S-SS IDs used by terminals that have selected the synchronization signal of the base station as a synchronization reference among physical layer SLSS IDs {0, 1, ..., 335}, {0, 1,. .., 167}. In addition, S-SS id_oon is a set of S-SS IDs used when base stations/out-of-coverage terminals transmit synchronization signals by themselves, and may be {168, 169,..., 335}.

As described above, unlike conventional signal transmission and reception between a base station and a terminal, in sidelink communication between terminals, resource allocation, time synchronization setting, and reference signal transmission are performed independently or in conjunction with the base station.

In particular, in the case of next-generation radio access technology (including terms such as NR and 5G), a number of protocols between the base station and the terminal have been added/modified. Therefore, unlike the conventional V2X communication protocol based on LTE technology, it is necessary to newly develop various protocols even in the case of sidelink communication based on NR technology.

In the present disclosure, when a transmitting terminal and a receiving terminal perform sidelink communication, operations such as synchronization signal reception, resource allocation, PSCCH, PSSCH, and DMRS configuration are proposed. Each embodiment to be described below is described centering on sidelink communication, but as described above, it can be equally applied to C-V2X and D2D communication.

As the subcarrier spacing (SCS) of an OFDM communication system changes in NR, a frame structure of a sidelink used for transmitting and receiving information in sidelink communication is also required to be changed.

The sidelink signal in this embodiment may use a waveform of CP-OFDM type among CP-OFDM type and DFT-s-OFDM type. In addition, the sidelink may use the following subcarrier spacing (hereinafter referred to as SCS). For example, in frequency range (FR) 1 using a frequency band of less than 6 GHz, SCS of 15 kHz, 30 kHz, and 60 kHz are used, and at this time, the 60 kHz interval showing the best performance can be set to mainly use. In FR 2, which uses a frequency band of 6 GHz or higher, 60 kHz and 120 kHz intervals are used, and the 60 kHz band can be mainly used.

In addition, the sidelink uses a cyclic prefix (CP) to prevent modulation that may occur during wireless communication transmission and reception, and its length may be set equal to the normal CP length of the NR Uu interface. If necessary, an extended CP may be applied.

As described above, sidelink communication can be performed based on NR radio access technology. In addition, when considering a scenario for sidelink communication, there is a possibility that a plurality of terminals may perform communication in a dense manner within a certain range, such as a plurality of vehicles performing group driving.

In this case, a problem in which radio resources for sidelink communication frequently collide may occur. In particular, unlike Mode 1, in which the base station allocates and schedules sidelink communication resources, in Mode 2, in which the terminal selects sidelink communication resources based on sensing operations within a certain resource pool, resource collision and an adjustment procedure are required. It can be.

In this situation, an embodiment of a technology for adjusting radio resources will be described below.

9 is a diagram for explaining a communication operation using adjustment information according to an exemplary embodiment.

Referring to FIG. 9 , sidelink communication may be performed between a UE-B (TX UE 900) and an RX UE 920. In this case, the UE-B 900 transmits data to the RX-UE 920 using resources for performing sidelink communication.

However, in the case of a sidelink resource allocation mode in which the UE-B 900 selects resources for performing sidelink communication, resources used by other terminals may overlap. When resources overlap, sidelink communication may not be performed smoothly.

Accordingly, UE-A 910 may transmit adjustment information to UE-B 900 to prevent a resource collision problem. For example, the UE-B 900 may prevent collision by selecting a radio resource to be used for sidelink communication based on the received coordination information (RSAI). That is, UE-A 910 may be a coordinator UE that provides RSAI (Resource Selection Assistance Information) to UE-B 900 through inter-UE coordination. Meanwhile, UE-B (900) is a TX UE that receives adjustment information from UE-A (910).

Specifically, the following embodiment can be applied for coordination between terminals in sidelink resource allocation mode 2 (a mode in which a terminal autonomously selects sidelink resources).

For example, UE-A 910 transmits preferred resource information that can be used by UE-B 900 and/or non-preferred resource information that cannot be used by UE-B 900 at the request of UE-B 900 . can transmit

As another example, even if there is no request from UE-B 900, UE-A 910 transmits UE-B 900 whether to collide with sidelink radio resources to be used and adjustment information indicating the collision resources. It can be transmitted to B (900).

However, in the case of the embodiment of transmitting and receiving the adjustment information as described above, there are various execution problems such as whether the UE-B 900 can process the adjustment information and whether or not what information should be included in the adjustment information. Therefore, hereinafter, various embodiments will be described focusing on operations for smooth transmission and reception of adjustment information in more detail. Hereinafter, for convenience of explanation, a terminal that receives adjustment information is described as a terminal and a terminal that transmits adjustment information is described as another terminal. However, the role of each terminal may be specifically described as needed.

10 is a diagram for describing an operation of a terminal according to an exemplary embodiment.

Referring to FIG. 10, a terminal may perform a step of transmitting sidelink control information including request information for requesting coordination information and indication information indicating a resource type to be included in the coordination information to another terminal (S1010). .

The terminal may be configured to select a sidelink radio resource by receiving adjustment information through higher layer signaling. Higher layer signaling may be received from the base station and may be an RRC message. For example, whether to process adjustment information of the terminal may be indicated through disable or enable processing of a specific field in the RRC message.

The terminal may request adjustment information in order to select a resource for sidelink communication.

For example, a terminal may include request information for requesting adjustment information in sidelink control information and transmit the same to another terminal. As another example, the terminal may transmit sidelink control information to other terminals by including indication information for indicating a resource type to be included in the adjustment information. As another example, the terminal may include both the request information and the indication information in the sidelink control information and transmit the same to another terminal.

For example, sidelink control information including request information and/or indication information may be transmitted through Physical Sidelink Shared CHannel (PSSCH). The sidelink control information includes first sidelink control information included in the PSCCH and second sidelink control information included in the PSSCH. In this case, the aforementioned request information and/or indication information may be included in the second sidelink control information.

Specifically, the request information may indicate whether the terminal requests adjustment information.

For example, the request information may be indicated by a value of a first field composed of 1 bit included in sidelink control information. The value of the first field may be used to distinguish whether the sidelink control information is for requesting adjustment information or providing adjustment information. That is, the first field is a field for distinguishing whether sidelink control information including request information is used to request adjustment information or is used to include and provide adjustment information. For example, if the value of the first field is set to '0', the corresponding sidelink control information may mean requesting adjustment information, and other fields and/or values of other fields may be changed accordingly. If the value of the first field is set to '1', it may mean that the corresponding sidelink control information includes adjustment information, and in this case, adjustment information may be additionally included. Of course, the values of the first field may be set opposite to each other.

As another example, the indication information may be indicated by a value of a second field composed of 1 bit different from the first field included in the sidelink control information. For example, the second field may be included when the value of the first field is set to request adjustment information. The second field may indicate which resource type is requested by the adjustment information requested by the terminal. For example, another terminal that transmits the adjustment information may include preferred resource information in the adjustment information and transmit the adjustment information. Alternatively, other terminals may include non-preferred resource information in the adjustment information and transmit it. Accordingly, when requesting adjustment information, the terminal may designate which information (resource type) to request. That is, the value of the second field may be used to indicate any one resource type of preferred resource information and non-preferred resource information determined by another terminal. If the value of the second field is set to '0', it can be interpreted as a request from the terminal to transmit preferred resource information as adjustment information. In contrast, if the value of the second field is set to '1', it can be interpreted as a request from the terminal to transmit non-preferred resource information as adjustment information.

In this way, when requesting adjustment information, the terminal may request a necessary resource type together.

The terminal may perform a step of receiving adjustment information from another terminal (S1020).

For example, when a terminal requests adjustment information, it may receive adjustment information from another terminal. Adjustment information may be received through PSSCH or PSCCH. When the other terminal receives sidelink control information requesting adjustment information from the terminal, it may generate preferred resource information or non-preferred resource information in consideration of resource sensing results sensed by other terminals, resource use information, and the like. In addition, another terminal may generate any one of preferred resource information and non-preferred resource information based on the indication information received from the terminal and transmit it to the terminal.

A terminal may receive preferred resource information or non-preferred resource information as adjustment information from another terminal based on transmission of sidelink control information including request information and indication information.

The terminal may perform a step of determining a resource for performing sidelink communication based on at least one of coordination information and resource sensing information (S1030).

For example, the terminal may select a resource for performing sidelink communication using at least one of adjustment information and sensing result resource information sensed in a sensing window. The UE needs to select a sidelink radio resource in order to communicate with the target UE (RX UE 920 in FIG. 9). In particular, in mode 2, since the base station configures a sidelink radio resource pool for the terminal and the terminal selects a resource in the pool, the terminal must directly select the corresponding resource.

In order to select a sidelink radio resource, the terminal selects a specific radio resource using a resource sensing result within a preset sensing window. As the resource sensing result, a channel measurement result such as RSRP for a specific frequency resource may be used.

Meanwhile, in this embodiment, the terminal may select a sidelink radio resource using both the sensing result resource information and the aforementioned adjustment information.

For example, when the preferred resource information is included in the adjustment information, the terminal may select a resource commonly included in the sensing result resource information and the preferred resource information as a resource for performing sidelink communication.

As another example, when the preferred resource information is included in the adjustment information, the terminal may select a resource for performing sidelink communication from the preferred resource information without using the resource information as a result of sensing.

As another example, when non-preferred resource information is included in the adjustment information, the terminal may select a resource for performing sidelink communication excluding radio resources included in the non-preferred resource information from among the sensing result resource information.

The aforementioned preferred resource information may include information about radio resources that other terminals prefer to use. The non-preferred resource information may include information about radio resources that other terminals expect the terminal to not use.

As such, when the adjustment information is received, the terminal may select a sidelink radio resource based on the sensing result resource information and the adjustment information. Through this operation, the terminal can reduce the probability of occurrence of a communication problem due to resource collision even in an environment in which a plurality of terminals perform sidelink communication. In addition, unnecessary increase in system overhead can be prevented by requesting adjustment information and indicating a specific resource type as needed.

In the above, the operation according to the explicit request among the methods for transmitting and receiving the adjustment information has been described, but is not limited thereto. Below, more various embodiments that can be performed by the aforementioned terminal will be described in detail.

For example, a UE may transmit an index of N bits through a specific sidelink control information format to deliver the type of inter-UE coordination information necessary for sidelink resource sensing to other UEs.

For example, an N-bit index may consist of 2 bits. The 2-bit index may indicate whether the terminal requests adjustment information and the requested resource type as shown in Table 2 below. Table 2 exemplarily discloses contents requesting up to the adjustment information scheme type at once using 2 bits.

Index Scheme Type Container 0 - Reconciliation information not required ^2nd SCI format in PSSCH One One Preferred and/or non-preferred resource set requests ^2nd SCI format in PSSCH 2 2 Presence of expected/potential resource conflict PSFCH-like 3 2 Presence of expected/potential resource conflict and detected resource conflict PSFCH-like

As another example, the terminal may indicate whether adjustment information is requested using 1 bit of 2 bits. In addition, the type of the requested resource may be indicated using the remaining 1 bit. For example, as shown in Table 3, the terminal may indicate whether adjustment information is requested using 1 bit, and may indicate the resource type through the remaining 1 bit.

first beat second beat request content 0 - No reconciliation information requested One - Reconciliation Information Request - 0 Preferred resource set request - One Request a non-preferred resource set

2 bits may be composed of the same field or may be composed of different fields.

As another example, the terminal may include information indicating whether adjustment information can be received in the sidelink control information transmitted through the PSCCH. That is, when a terminal indicates that it can receive adjustment information in sidelink control information transmitted through PSCCH, a collision occurs when another terminal collides with or is expected to collide with a sidelink radio resource reserved for use by the terminal. It is possible to transmit adjustment information indicating whether or not.

As described above, the terminal may indicate a request for adjustment information and a resource type through various methods.

Hereinafter, the configuration of the terminal described above will be described once again with reference to the drawings.

11 is a diagram for explaining a configuration of a terminal according to an embodiment.

Referring to FIG. 11, a terminal 1100 performing sidelink communication transmits sidelink control information including request information for requesting adjustment information and indication information indicating a resource type to be included in the adjustment information to another terminal. It may include a transmitter 1120 for performing sidelink communication, a receiver 1130 for receiving adjustment information from other terminals, and a control unit 1110 for determining a resource for performing sidelink communication based on at least one of the adjustment information and resource sensing information. there is.

The terminal 1100 may be configured to select a sidelink radio resource by receiving adjustment information through higher layer signaling. Higher layer signaling may be received from the base station and may be an RRC message. For example, whether to process adjustment information of the terminal may be indicated through disable or enable processing of a specific field in the RRC message.

Terminal 1100 may request adjustment information in order to select a resource for sidelink communication.

For example, the transmitter 1120 may include request information for requesting adjustment information in sidelink control information and transmit the same to other terminals. As another example, the transmitter 1120 may transmit sidelink control information to other terminals by including indication information for indicating a resource type to be included in the adjustment information. As another example, the transmitter 1120 may include both request information and indication information in sidelink control information and transmit the same to other terminals.

For example, sidelink control information including request information and/or indication information may be transmitted through Physical Sidelink Shared CHannel (PSSCH). The sidelink control information includes first sidelink control information included in the PSCCH and second sidelink control information included in the PSSCH. In this case, the aforementioned request information and/or indication information may be included in the second sidelink control information.

Specifically, the request information may indicate whether the terminal requests adjustment information.

For example, the request information may be indicated by a value of a first field composed of 1 bit included in sidelink control information. The value of the first field may be used to distinguish whether the sidelink control information is for requesting adjustment information or providing adjustment information. That is, the first field is a field for distinguishing whether sidelink control information including request information is used to request adjustment information or is used to include and provide adjustment information. For example, if the value of the first field is set to '0', the corresponding sidelink control information may mean requesting adjustment information, and other fields and/or values of other fields may be changed accordingly. If the value of the first field is set to '1', it may mean that the corresponding sidelink control information includes adjustment information, and in this case, adjustment information may be additionally included. Of course, the values of the first field may be set opposite to each other.

As another example, the indication information may be indicated by a value of a second field composed of 1 bit different from the first field included in the sidelink control information. For example, the second field may be included when the value of the first field is set to request adjustment information. The second field may indicate which resource type is requested by the adjustment information requested by the terminal. For example, another terminal that transmits the adjustment information may include preferred resource information in the adjustment information and transmit the adjustment information. Alternatively, other terminals may include non-preferred resource information in the adjustment information and transmit it. Accordingly, when requesting adjustment information, the terminal may designate which information (resource type) to request. That is, the value of the second field may be used to indicate any one resource type of preferred resource information and non-preferred resource information determined by another terminal. If the value of the second field is set to '0', it can be interpreted as a request from the terminal to transmit preferred resource information as adjustment information. In contrast, if the value of the second field is set to '1', it can be interpreted as a request from the terminal to transmit non-preferred resource information as adjustment information.

In this way, when requesting adjustment information, the terminal may request a necessary resource type together.

Meanwhile, the receiving unit 1130 may receive adjustment information from other terminals when requesting adjustment information. Adjustment information may be received through PSSCH or PSCCH. When the other terminal receives sidelink control information requesting adjustment information from the terminal, it may generate preferred resource information or non-preferred resource information in consideration of resource sensing results sensed by other terminals, resource use information, and the like. In addition, another terminal may generate any one of preferred resource information and non-preferred resource information based on the indication information received from the terminal and transmit it to the terminal.

The receiving unit 1130 may receive preferred resource information or non-preferred resource information as adjustment information from other terminals based on transmission of sidelink control information including request information and indication information.

Meanwhile, the control unit 1110 may determine resources for performing sidelink communication using adjustment information.

For example, the controller 1110 may select a resource for performing sidelink communication using at least one of adjustment information and sensing result resource information sensed in a sensing window.

The controller 1110 selects a specific radio resource by using a resource sensing result within a preset sensing window in order to select a sidelink radio resource. As the resource sensing result, a channel measurement result such as RSRP for a specific frequency resource may be used.

Meanwhile, in this embodiment, the terminal may select a sidelink radio resource using both the sensing result resource information and the aforementioned adjustment information.

For example, when preferred resource information is included in the adjustment information, the control unit 1110 may select a resource commonly included in the sensing result resource information and the preferred resource information as a resource for performing sidelink communication.

As another example, when the preferred resource information is included in the adjustment information, the control unit 1110 may select a resource for performing sidelink communication from the preferred resource information without using the resource information as a result of sensing.

As another example, when non-preferred resource information is included in the adjustment information, the control unit 1110 may select a resource for performing sidelink communication excluding radio resources included in the non-preferred resource information from the sensing result resource information.

The aforementioned preferred resource information may include information about radio resources that other terminals prefer to use. The non-preferred resource information may include information about radio resources that other terminals expect the terminal to not use.

In addition to this, the control unit 1110 may control the operation of the terminal 1100 required to perform the present embodiments described above.

In addition, the transmitter 1120 and the receiver 1130 transmit and receive signals, data, and messages to and from the base station and other terminals through corresponding channels.

As such, when the adjustment information is received, the terminal may select a sidelink radio resource based on the sensing result resource information and the adjustment information. Through this operation, the terminal can reduce the probability of occurrence of a communication problem due to resource collision even in an environment in which a plurality of terminals perform sidelink communication. In addition, unnecessary increase in system overhead can be prevented by requesting adjustment information and indicating a specific resource type as needed.

The above-described embodiments may be supported by standard documents disclosed in at least one of IEEE 802, 3GPP, and 3GPP2, which are wireless access systems. That is, among the present embodiments, steps, configurations, and parts not described to clearly reveal the present technical idea may be supported by the above-mentioned standard documents. In addition, all terms disclosed in this specification can be explained by the standard documents disclosed above.

The present embodiments described above may be implemented through various means. For example, the present embodiments may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to the present embodiments includes one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, or microprocessors.

In the case of implementation by firmware or software, the method according to the present embodiments may be implemented in the form of a device, procedure, or function that performs the functions or operations described above. The software codes may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor and exchange data with the processor by various means known in the art.

Also, the terms "system", "processor", "controller", "component", "module", "interface", "model", or "unit" as described above generally refer to computer-related entities hardware, hardware and software. can mean a combination of, software or running software. For example, but is not limited to, a process driven by a processor, a processor, a controller, a control processor, an object, a thread of execution, a program, and/or a computer. For example, a component can be both an application running on a controller or processor and a controller or processor. One or more components may reside within a process and/or thread of execution, and components may reside on one device (eg, system, computing device, etc.) or may be distributed across two or more devices.

The above description is merely illustrative of the technical idea of the present disclosure, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the technical idea. In addition, since the present embodiments are not intended to limit the technical idea of the present disclosure, but to explain, the scope of the present technical idea is not limited by these embodiments. The scope of protection of the present disclosure should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of rights of the present disclosure.

Claims (14)

In a method for performing sidelink communication by a terminal,
Transmitting sidelink control information including request information for requesting adjustment information and indication information indicating a resource type to be included in the adjustment information to another terminal;
receiving the adjustment information from the other terminal; and
And determining a resource for performing sidelink communication based on at least one of the adjustment information and the resource sensing information. According to claim 1,
The sidelink control information,
A method characterized in that transmitted by being included in PSSCH (Physical Sidelink Shared CHannel). According to claim 1,
The requested information is
Indicated by the value of the first field consisting of 1 bit,
The instruction information is
characterized in that it is indicated by a value of a second field consisting of 1 bit distinct from the first field. According to claim 3,
The value of the first field is,
The method characterized in that used to distinguish whether the sidelink control information is for requesting the adjustment information or for providing the adjustment information. According to claim 3,
The value of the second field is
characterized in that it is used to indicate the resource type of any one of preferred resource information and non-preferred resource information determined by the other terminal. According to claim 1,
The step of determining the resource is,
and selecting a resource for performing the sidelink communication using at least one of the adjustment information and sensing result resource information sensed in a sensing window. According to claim 6,
The step of determining the resource is,
When preferred resource information is included in the adjustment information, a resource commonly included in the sensing result resource information and the preferred resource information is selected as a resource for performing the sidelink communication. According to claim 6,
The step of determining the resource is,
When the adjustment information includes non-preferred resource information, selecting a resource for performing the sidelink communication excluding radio resources included in the non-preferred resource information from among the sensing result resource information. In a terminal performing sidelink communication,
a transmitter for transmitting sidelink control information including request information for requesting adjustment information and indication information indicating a resource type to be included in the adjustment information to another terminal;
a receiving unit receiving the adjustment information from the other terminal; and
A terminal including a control unit for determining a resource for performing sidelink communication based on at least one of the adjustment information and the resource sensing information. According to claim 9,
The sidelink control information,
A terminal characterized in that it is transmitted while being included in PSSCH (Physical Sidelink Shared CHannel). According to claim 9,
The requested information is
Indicated by the value of the first field consisting of 1 bit,
The instruction information is
Characterized in that indicated by the value of the second field consisting of 1 bit distinguished from the first field. According to claim 11,
The value of the first field is,
The terminal, characterized in that used to distinguish whether the sidelink control information is for requesting the adjustment information or for providing the adjustment information. According to claim 11,
The value of the second field is
Characterized in that used to indicate the resource type of any one of preferred resource information and non-preferred resource information determined by the other terminal. According to claim 9,
The control unit,
The terminal, characterized in that for selecting a resource for performing the sidelink communication using at least one of the adjustment information and sensing result resource information sensed in a sensing window.

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