Patent Description:
To meet the soaring demand with respect to wireless data traffic since commercialization of <NUM>th-Generation (<NUM>) communication systems, efforts have been made to develop improved <NUM>th-Generation (<NUM>) communication systems or pre-<NUM> communication systems. For this reason, <NUM> communication systems or pre-<NUM> communication systems are also called beyond-<NUM>-network communication systems or post-long term evolution (LTE) systems.

It is considered that the <NUM> communication system will be implemented in millimeter wave (mmWave) bands, e.g., <NUM> bands, so as to accomplish higher data rates. In <NUM> communication systems, beamforming, massive multiinput multi-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and large-scale antenna technologies have been discussed as ways of alleviating propagation path loss and increasing propagation distances in ultra-high frequency bands.

In order to improve system networks for <NUM> communication systems, various technologies have been developed, such as evolved small cell, advanced small cell, cloud radio access network (RAN), ultra-dense network, device to device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMPs), and interference cancellation.

For <NUM> systems, other technologies have been developed, such as, hybrid frequency-shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and sliding window superposition coding (SWSC), which are advanced coding modulation (ACM) schemes, and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA), which are advanced access schemes.

Various schemes for determining radio resources in <NUM> systems are also under discussion. For example, a direct communication scheme for vehicle to everything (V2X) user equipment (UE) has been proposed. Moreover, in direct communication between UEs, there have been various discussions about shortening a communication time, improving reliability, and efficiently performing direct communication between UEs.

<NPL>, discloses various proposals for sidelink broadcast in NR, based on LTE sidelink. "Resource allocation for Enhanced Mobility" by Ericsson proposes SIB resource pool configuration for sidelink V2X with validity areas.

<CIT> concerns facilitating reporting assistance information for sidelink service in wireless communications systems.

The invention is set out in the appended set of claims, wherein the figures and respective description relate to advantageous embodiments thereof. Accordingly, an aspect of the disclosure is to provide an apparatus and method for supporting a vehicle communication service and data transmission, in which required values for high reliability and low latency are achieved by providing a method performed using a direct communication scheme between UEs in a vehicle communication system.

It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purposes only and not for the purpose of limiting the disclosure as defined by the appended claims.

All of the terms used herein including technical or scientific terms have the same meanings as those generally understood by an ordinary skilled person in the related art. The terms defined in a generally used dictionary should be interpreted as having meanings that are the same as or similar with the contextual meanings of the relevant technology and should not be interpreted as having ideal or exaggerated meanings unless they are clearly defined in the various embodiments of the disclosure. Depending on a case, terms defined in the disclosure cannot be analyzed to exclude the various embodiments of the disclosure.

A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions.

In the disclosure, a controller may be referred to as a processor.

In the disclosure, a layer (layer device) may be referred to as an entity.

In various embodiments of the disclosure described below, a hardwarebased access method will be described as an example. However, various embodiments of the disclosure include a technique using both hardware and software, such that the various embodiments of the disclosure do not exclude a software-based access method.

The disclosure relates to an apparatus and method for determining radio resources in a wireless communication system. More specifically, the disclosure presents a description of a technique capable of satisfying a quality of service (QoS) level required for various V2X services based on a sidelink radio resource grant method for sidelink direct communication between vehicle-to-everything (V2X) UEs in a wireless communication system.

As used below, a term indicating a signal, a term indicating a channel, a term indicating control information, a term indicating network entities, a term indicating a component of an apparatus, etc., will be presented for convenience of description. However, the disclosure is not limited by the following terms, and other terms having equivalent technical meanings may be used.

Although the disclosure will be described with reference to various embodiments thereof by using terms used in some communication standards (e.g., the <NUM>rd Generation Partnership Project: 3GPP), those are merely examples used for description. Various embodiments of the disclosure may be easily modified for application to other communication systems.

Accordingly, an aspect of the disclosure is to provide an apparatus and method for supporting a vehicle communication service and data transmission, in which required values for high reliability and low latency are achieved by providing a method performed using a direct communication scheme between UEs in a vehicle communication system.

Another aspect of the disclosure, in a next-generation radio access network (ng-RAN) (gNodeB (gNB)) connected to a <NUM> core network or an evolved universal mobile telecommunication system (UMTS) terrestrial radio access network (E-UTRAN) (ng-evolved NB: ng-eNB) connected to the <NUM> core network, a UE may perform a V2X service through the ng-RAN or the E-UTRAN.

In accordance with another aspect of the disclosure, when a base station (ng-RAN or ng-eNB) is connected to an evolved packet core network (EPC), the UE may perform the V2X service through the base station. According to another embodiment of the disclosure, when a base station (eNB) is connected to the EPC, the UE may perform the V2X service through the base station. In this case, a V2X wireless interface communication scheme available for direct communication between UEs may include at least one of a unicast scheme, a groupcast scheme, or a broadcast scheme, and the disclosed embodiment provides a method of granting radio resources to be used for V2X transmission and reception in each communication scheme.

In accordance with another aspect of the disclosure, a method, performed by a user equipment (UE), of performing sidelink communication includes obtaining a valid system information block (SIB) for sidelink communication, autonomously determining a sidelink resource based on information of a pool of sidelink resources included in the valid SIB for sidelink communication, and performing sidelink communication with another UE using the determined sidelink resource.

<FIG> illustrates a wireless communication system according to an embodiment of the disclosure.

Referring to <FIG>, a base station (BS) <NUM>, a UE <NUM>, and a UE <NUM> are illustrated as nodes using a wireless channel in a wireless communication system. While <FIG> shows one BS <NUM>, another BS that is the same as or similar to the BS <NUM> may be further included in the wireless communication system. In addition, while <FIG> shows two UEs <NUM> and <NUM>, another UE that is the same as or similar to the UEs <NUM> and <NUM> may be further included in the wireless communication system.

The BS <NUM> may be a network infrastructure that provides the UEs <NUM> and <NUM> with a radio access. The BS <NUM> may have a coverage defined as a geographic region based on a distance in which signal transmission/reception is possible. The BS <NUM> may be referred to as not only the 'BS', but also an 'access point (AP)', an 'evolved NodeB (eNB)', a '<NUM>th-generation (<NUM>) node', a '<NUM> NodeB (gNodeB or gNB)', a 'wireless point', a 'transmission/reception point (TRP)', or other terms having technical meanings equivalent thereto.

Each of the UEs <NUM> and <NUM> is a device used by a user, and may perform communication with the BS <NUM> through a wireless channel. Depending on a case, at least one of the UEs <NUM> and <NUM> may operate regardless of a user's intervention. That is, at least one of the UEs <NUM> and <NUM> may be a device performing machine type communication (MTC), and thus may not be carried by the user. Each of the UEs <NUM> and <NUM> may be referred to as not only a 'UE', but also a 'terminal', a 'mobile station (MS)', a 'subscriber station (SS)', a 'remote terminal', a 'wireless terminal', a 'user device', or other terms having technical meanings equivalent thereto.

The BS <NUM>, the UE <NUM>, and the UE <NUM> may transmit and receive a radio frequency (RF) signal in a sub <NUM> band and a millimeter wave (mmWave) band (e.g., <NUM>, <NUM>, <NUM>, or <NUM>). In this case, to improve a channel gain, the BS <NUM>, the UE <NUM>, and the UE <NUM> may perform beamforming. Beamforming may include transmission beamforming and reception beamforming. That is, the BS <NUM>, the UE <NUM>, and the UE <NUM> may give directivity to a transmission signal or a reception signal. To this end, the BS <NUM> and the UEs <NUM> and <NUM> may select serving beams <NUM>, <NUM>, <NUM>, and <NUM> through a beam search procedure or a beam management procedure. After the serving beams <NUM>, <NUM>, <NUM>, and <NUM> are selected, communication may be performed using resources having a quasi co-location (QLC) relationship with resources used for transmission of the serving beams <NUM>, <NUM>, <NUM>, and <NUM>.

When large-scale properties of a channel carrying a symbol on a first antenna port may be inferred from a channel carrying a symbol on a second antenna port, the first antenna port and the second antenna port may be evaluated as having a QCL relationship with each other. For example, the large-scale properties of the channel may include at least one of delay spread, Doppler spread, a Doppler shift, an average gain, an average delay, or a spatial receiver parameter.

<FIG> is a block diagram of a base station in a wireless communication system according to an embodiment of the disclosure. A configuration illustrated in <FIG> may be understood as a configuration of the BS <NUM>. The term used below such as 'unit', 'module', or the like indicates a unit for processing at least one function or operation, and may be implemented in hardware, software, or in a combination of hardware and software.

Referring to <FIG>, the BS <NUM> may include a wireless communicator <NUM>, a backhaul communicator <NUM>, a storage <NUM>, and a controller <NUM>.

The wireless communicator <NUM> may perform functions for transmitting and receiving a signal through a wireless channel. For example, the wireless communicator <NUM> may perform conversion between a baseband signal and a bitstream according to physical layer standards of a system. In data transmission, the wireless communicator <NUM> may generate complex symbols by encoding and modulating a transmission bitstream. In data reception, the wireless communicator <NUM> may recover a received bitstream by demodulating and decoding a baseband signal.

The wireless communicator <NUM> may also up-convert a baseband signal into a radio frequency (RF) band signal, transmit the RF band signal through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal. To this end, the wireless communicator <NUM> may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and so forth. The wireless communicator <NUM> may also include multiple transmission/reception paths. The wireless communicator <NUM> may further include at least one antenna array including multiple antenna elements.

In terms of hardware, the wireless communicator <NUM> may include a digital unit and an analog unit, in which the analog unit may include multiple sub-units depending on operating power, operating frequency, etc. The digital unit may be implemented with at least one processor (e.g., a digital processor: DSP).

The wireless communicator <NUM> may transmit and receive a signal as described above. Thus, the entire wireless communicator <NUM> or a part thereof may be referred to as a 'transmitter', a 'receiver', or a 'transceiver'. In addition, in the following description, transmission and reception performed through a wireless channel may include a meaning of the above-described processing performed by the wireless communicator <NUM>.

The backhaul communicator <NUM> may provide an interface for performing communication with other nodes in a network. The backhaul communicator <NUM> may convert a bitstream transmitted from a BS to another node, e.g., another access node, another BS, a high-layer node, a core network, etc., into a physical signal, and convert a physical signal received from another node into a bitstream.

The storage <NUM> may store data such as a basic program for operations of the BS <NUM>, an application program, configuration information, and so forth. The storage <NUM> may include a volatile memory, a non-volatile memory, a combination of the volatile memory and the non-volatile memory, and/or the like. The storage <NUM> may provide stored data at the request of the controller <NUM>.

The controller <NUM> may control overall operations of the BS <NUM>. For example, the controller <NUM> may transmit and receive a signal through the wireless communicator <NUM> or the backhaul communicator <NUM>. The controller <NUM> may record and read data from and in the storage <NUM>. The controller <NUM> may perform functions of a protocol stack required in the communication standards. According to another implementation example, the protocol stack may be included in the wireless communicator <NUM>. To this end, the controller <NUM> may include at least one processor.

According to various embodiments of the disclosure, the controller <NUM> may transmit radio resource control (RRC) configuration information to a UE <NUM> or <NUM>. The controller <NUM> may transmit sidelink configuration information to the UE <NUM> or <NUM>. For example, the controller <NUM> may control the BS <NUM> to perform operations according to various embodiments of the disclosure described below.

<FIG> is a block diagram of a user equipment (UE) in a wireless communication system according to an embodiment of the disclosure. A configuration illustrated in <FIG> may be understood as a configuration of the UE <NUM> or <NUM>. The term used below such as 'unit', 'module', or the like indicates a unit for processing at least one function or operation, and may be implemented in hardware, software, or in a combination of hardware and software.

Referring to <FIG>, the UE may include a communicator <NUM>, a storage <NUM>, and a controller <NUM>.

The communicator <NUM> may perform functions for transmitting and receiving a signal through a wireless channel. For example, the communicator <NUM> may perform conversion between a baseband signal and a bitstream according to physical layer standards of a system. In data transmission, the communicator <NUM> may generate complex symbols by encoding and modulating a transmission bitstream. In data reception, the communicator <NUM> may recover a received bitstream by demodulating and decoding a baseband signal. The communicator <NUM> may also up-convert a baseband signal into an RF band signal, transmit the RF band signal through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal. The communicator <NUM> may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and so forth.

The communicator <NUM> may also include multiple transmission/reception paths. The communicator <NUM> may include at least one antenna array including multiple antenna elements. In terms of hardware, the communicator <NUM> may include a digital circuit and an analog circuit (e.g., a radio frequency integrated circuit: RFIC). Herein, the digital circuit and the analog circuit may be implemented with one package. The communicator <NUM> may include multiple RF chains. Moreover, the communicator <NUM> may perform beamforming.

In addition, the communicator <NUM> may include multiple communication modules for processing signals in different frequency bands. Moreover, the communicator <NUM> may include multiple communication modules for supporting multiple different RATs. For example, the different RATs may include Bluetooth low energy (BLE), WiFi, WiFi gigabyte (WiGig), a cellular network (e.g., Long Term Evolution (LTE)), etc. The different frequency bands may include a super high frequency (SHF) (e.g., <NUM>, <NUM>, <NUM>) band, and an mm waves (millimeter wave) (e.g., <NUM>) band.

The communicator <NUM> may transmit and receive a signal as described above. Thus, the entire communicator <NUM> or a part thereof may be referred to as a 'transmitter', a 'receiver', or a 'transceiver'. In addition, in the following description, transmission and reception performed through a wireless channel may include a meaning of the above-described processing performed by the communicator <NUM>.

The storage <NUM> may store data such as a basic program for operations of the UE, an application program, configuration information, and so forth. The storage <NUM> may include a volatile memory, a non-volatile memory, a combination of the volatile memory and the non-volatile memory, and/or the like. The storage <NUM> may provide stored data at the request of the controller <NUM>.

The controller <NUM> may control overall operations of the UE. For example, the controller <NUM> may transmit and receive a signal through the communicator <NUM>. The controller <NUM> may record and read data from and in the storage <NUM>. The controller <NUM> may perform functions of a protocol stack required in the communication standards. For this, the controller <NUM> may include at least one processor or microprocessor, or may be implemented as a part of a processor. A part of the communicator <NUM> and the controller <NUM> may be referred to as a communication processor (CP).

According to various embodiments of the disclosure, when the UE <NUM> performs sidelink direct communication with another UE, the UE <NUM> may perform a process of identifying service information required by a V2X application and determining a V2X transmission mode (unicast, groupcast, or broadcast), a process of determining a sidelink resource grant mode (BS scheduling or UE scheduling) required for V2X packet transmission, a process of determining a sidelink resource grant mode (BS scheduling or UE scheduling) required for hybrid automatic repeat request (HARQ) feedback transmission for a V2X packet, a process of performing sidelink transmission resource or HARQ feedback transmission resource grant in a BS scheduling mode, a process of performing sidelink transmission resource or HARQ feedback transmission resource grant in a UE scheduling mode, a process of performing configured grant-based sidelink resource grant in the UE scheduling mode, a process of performing a scheduling UE operation for performing sidelink resource grant of another UE in the UE scheduling mode, and a process of performing an assistant UE operation for assisting sidelink resource grant of another UE in the UE scheduling mode. For example, the controller <NUM> may control the UE to perform operations according to various embodiments of the disclosure described below.

4A through 4C illustrate structures of a communicator in a wireless communication system according to various embodiments of the disclosure. 4A through 4C illustrate an example of a detailed structure of the wireless communicator <NUM> of <FIG> or the communicator <NUM> of <FIG>. More specifically, FIGS. 4A through 4C illustrate components for performing beamforming, as a part of the wireless communicator <NUM> of <FIG> or the communicator <NUM> of <FIG>.

Referring to FIG. 4A, the wireless communicator <NUM> or the communicator <NUM> may include an encoder and modulator <NUM>, a digital beamformer <NUM>, multiple transmission paths <NUM>-<NUM> through <NUM>-N, and an analog beamformer <NUM>.

The encoder and modulator <NUM> may perform channel encoding. For channel encoding, at least one of a low density parity check (LDPC) code, a convolutional code, or a polar code may be used. The encoder and modulator <NUM> may generate modulation symbols by performing constellation mapping.

The digital beamformer <NUM> may perform beamforming with respect to a digital signal (e.g., modulation symbols). To this end, the digital beamformer <NUM> may multiply modulation symbols by beamforming weight values. The beamforming weight values may be used to convert an amplitude and a phase of a signal, and may be referred to as a 'precoding matrix', a 'precoder', etc. The digital beamformer <NUM> may output the digital-beamformed modulation symbols to the multiple paths <NUM>-<NUM> through <NUM>-N. In this case, according to a multiple-input multiple-output (MIMO) transmission scheme, the modulation symbols may be multiplexed or the same modulation symbols may be provided to the multiple transmission paths <NUM>-<NUM> through <NUM>-N.

The multiple transmission paths <NUM>-<NUM> through <NUM>-N may convert the digital-beamformed digital signals into an analog signal. To this end, each of the multiple transmission paths <NUM>-<NUM> through <NUM>-N may include an inverse fast Fourier transform (IFFT) operator, a cyclic prefix (CP) inserter, a digital-to-analog converter (DAC), and an up-converter. The CP inserter is for an orthogonal frequency division multiplexing (OFDM) scheme, and may be excluded when another physical layer scheme (e.g., filter bank multi-carrier: FBMC) is applied. The multiple transmission paths <NUM>-<NUM> through <NUM>-N may provide an independent signal processing process for multiple streams generated through digital beamforming. However, depending on an implementation scheme, some of the components of the multiple transmission paths <NUM>-<NUM> through <NUM>-N may be used in common.

The analog beamformer <NUM> may perform beamforming with respect to an analog signal. To this end, the analog beamformer <NUM> may multiply analog symbols by beamforming weight values. The beamforming weight values may be used to convert an amplitude and a phase of a signal. According to a connection structure between the multiple transmission paths <NUM>-<NUM> through <NUM>-N and antennas, the analog beamformer <NUM> may be structured as shown in <FIG> or <FIG>.

Referring to <FIG>, signals input to the analog beamformer <NUM> may be transmitted through the antennas, after passing through phase/amplitude conversion and an amplification operation. In this case, a signal of each path may be transmitted through different antenna sets, i.e., antenna arrays. In case of processing of a signal input through the first path, the signal may be converted into a signal sequence having different phases/amplitudes or the same phase/amplitude by phase/amplitude converters <NUM>-<NUM>-<NUM> through <NUM>-<NUM>-M, may be amplified by amplifiers <NUM>-<NUM>-<NUM> through <NUM>-<NUM>-M, and may then be transmitted through the antennas.

Referring to <FIG>, signals input to the analog beamformer <NUM> may be transmitted through the antennas, after passing through phase/amplitude conversion and an amplification operation. In this case, a signal of each path may be transmitted through the same antenna set, i.e., the same antenna array. In case of processing of a signal input through the first path, the signal may be converted into a signal sequence having different phases/amplitudes or the same phase/amplitude by the phase/amplitude converters <NUM>-<NUM>-<NUM> through <NUM>-N-M, and may be amplified by the amplifiers <NUM>-<NUM>-<NUM> through <NUM>-N-M. For transmission through one antenna array, the amplified signals may be summed by summers <NUM>-<NUM> through <NUM>-M based on an antenna element, and may then be transmitted through the antennas.

<FIG> illustrates an example in which an independent antenna array is used for each transmission path, and <FIG> illustrates an example in which transmission paths share one antenna array. However, the structure of the analog beamformer <NUM> is not limited to the embodiment shown in <FIG> and <FIG>, and according to another embodiment of the disclosure, some transmission paths may have an independent antenna array and the other transmission paths may share one antenna array. According to another embodiment of the disclosure, by applying a switchable structure between transmission paths and antenna arrays as the structure of the analog beamformer <NUM>, a structure that is changeable adaptively to a circumstance may be used.

The V2X service may be divided into a basic safety service and an advanced service. The basic safety service may include detailed services such as a vehicle notification (CAM or BSM) service, a left-turn notification service, a forward collision warning system, an emergency vehicle access notification service, a forward obstacle warning service, an intersection signal information service, etc., and V2X information may be transmitted and received using broadcast, unicast, or groupcast transmission. The advanced service reinforces QoS requirements when compared to the basic safety service, and requires a scheme for transmitting and receiving V2X information by using broadcast, unicast, or groupcast transmission to transmit and receive V2X information in a particular vehicle group or between two vehicles. The advanced service may include detailed services such as a platoon driving service, an autonomous driving service, a remote driving service, an extended sensor-based V2X service, etc. According to various embodiments of the disclosure, a description will be made of a scheme to select RAT resources for performing direct communication between vehicles required in the basic safety service or the advanced service, that is, sidelink resources needed for V2X packet transmission and sidelink resources needed for HARQ feedback transmission.

The methods according to the embodiments of the disclosure described in the claims or specification of the disclosure may be implemented by hardware, software, or a combination thereof.

When the methods are implemented by software, a computer-readable storage medium having stored therein one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium may be configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute the methods according to the embodiments described in the claims or the specification of the disclosure.

These programs (software modules and software) may be stored in random access memories (RAMs), non-volatile memories including flash memories, read only memories (ROMs), electrically erasable programmable ROMs (EEPROMs), magnetic disc storage devices, compact disc-ROMs (CD-ROMs), digital versatile discs (DVDs), other types of optical storage devices, or magnetic cassettes. The programs may be stored in a memory configured by a combination of some or all of such storage devices. Also, each of the memories may be provided in plurality.

The programs may be stored to an attachable storage device of the electronic device accessible via the communication network such as Internet, Intranet, a local area network (LAN), a wide area network (WAN), or storage area network (SAN), or a communication network by combining the networks. The storage device may access a device performing the embodiment of the disclosure through an external port. In addition, a separate storage device on a communication network may access a device performing an embodiment of the disclosure.

In the above-described detailed embodiments of the disclosure, components included in the disclosure have been expressed as singular or plural according to the provided detailed embodiments of the disclosure. However, singular or plural expressions have been selected properly for a condition provided for convenience of a description, and the disclosure is not limited to singular or plural components and components expressed as plural may be configured as a single component or a component expressed as singular may also be configured as plural components.

<FIG> illustrate a situation where direct communication between UEs is performed using sidelink radio access technology (RAT), according to various embodiments of the disclosure.

<FIG> illustrates a scenario in which UEs in a gNB coverage perform direct communication.

Referring to <FIG>, sidelink resource pool (transmission/reception pool) information to be used for unicast-based V2X packet transmission/reception between the UEs in the gNB coverage may be transmitted through a system information message or RRC dedicated message of a gNB or may be pre-configured. In addition to the sidelink resource pool to be used for unicast-based V2X packet transmission and reception between the UEs, a sidelink resource pool to be used for HARQ feedback transmission may be separately configured or may be configured identically to the V2X packet transmission/reception pool.

Referring to <FIG>, sidelink resource pool (transmission/reception pool) information to be used for broadcast-based V2X packet transmission/reception may be transmitted through the system information message or RRC dedicated message of the gNB or may be pre-configured.

<FIG> illustrates a scenario in which UEs in a ng-eNB coverage perform direct communication.

Referring to <FIG>, sidelink resource pool (transmission/reception pool) information to be used for unicast-based V2X packet transmission/reception between the UEs in the ng-eNB coverage may be transmitted through a system information message or RRC dedicated message of an ng-eNB or may be pre-configured. In addition to the sidelink resource pool to be used for unicast-based V2X packet transmission and reception between the UEs, a sidelink resource pool to be used for HARQ feedback transmission may be separately configured or may be configured identically to the V2X packet transmission/reception pool.

Referring to <FIG>, sidelink resource pool (transmission/reception pool) information to be used for broadcast-based V2X packet transmission/reception may be transmitted through the system information message or RRC dedicated message of the ng-eNB or may be pre-configured.

<FIG> illustrates a scenario in which a UE in a gNB coverage and a UE in an eNB coverage perform direct communication. Sidelink resource pool (transmission/reception pool) information to be used for unicast-based V2X packet transmission/reception between the UE in the gNB coverage and the UE in the eNB coverage may be transmitted through a system information message or RRC dedicated message of an ng-eNB or may be pre-configured. In addition to the sidelink resource pool to be used for unicast-based V2X packet transmission and reception between the UE in the gNB coverage and the UE in the eNB coverage, a sidelink resource pool to be used for HARQ feedback transmission may be separately configured or may be configured identically to the V2X packet transmission/reception pool.

In a sidelink resource grant scheme according to an embodiment of the disclosure, in a scheduling mode where a UE located in the gNB coverage plays a role of a scheduling UE or an assistant UE, the UE may be located in the gNB coverage and obtain sidelink pool information (which may include an HARQ feedback resource according to an embodiment of the disclosure) or pre-configured sidelink resource pool information, and play a role of a scheduling UE or an assistant UE by using the obtained pool information. In a sidelink resource grant scheme according to another embodiment of the disclosure, in a scheduling mode where a UE located in the eNB coverage plays a role of a scheduling UE or an assistant UE, the UE may be located in the eNB coverage and obtain pre-configured sidelink resource pool information and play a role of a scheduling UE or an assistant UE by using the obtained pool information.

<FIG> illustrates a scenario in which UEs in an eNB coverage perform direct communication. Sidelink resource pool (transmission/reception pool) information to be used for unicast-based V2X packet transmission/reception between the UEs in the eNB coverage may be pre-configured. In addition to the sidelink resource pool to be used for unicast-based V2X packet transmission and reception between the UEs in the eNB coverage, a sidelink resource pool to be used for HARQ feedback transmission may be separately configured or may be configured identically to the V2X packet transmission/reception pool.

Referring to <FIG>, sidelink resource pool (transmission/reception pool) information to be used for broadcast-based V2X packet transmission/reception may be pre-configured. In a sidelink resource grant scheme according to an embodiment of the disclosure, in a scheduling mode where a UE located in the eNB coverage plays a role of a scheduling UE or an assistant UE, the UE obtain pre-configured sidelink resource pool information and play a role of a scheduling UE or an assistant UE by using the obtained pool information.

In <FIG>, a broadcast pool and a unicast pool may be configured as the same pool or different pools. According to an embodiment of the disclosure, a criterion for configuring the broadcast pool and the unicast pool as the same pool or separate pools may be, for example, a case where a congestion ratio of a pool exceeds a threshold. A V2X server or a BS may manage a threshold for a congestion ratio of a pool corresponding to each V2X service and provide the V2X service, and when the congestion ratio of the pool exceeds the threshold, the broadcast and the unicast may be managed in the separate pools.

According to various embodiments of the disclosure, a method for sidelink resource grant for direct communication between UEs may be used for unicast-based V2X message transmission/reception and broadcast-based V2X message transmission/reception. According to various embodiments of the disclosure, a method for sidelink resource grant for direct communication between UEs may include a mode in which a BS directly grants a resource and a mode in which a UE directly selects a resource.

According to various embodiments of the disclosure, for unicast-based V2X packet transmission/reception, a reception UE may transmit an HARQ feedback with respect to a V2X packet. When a UE is located in the gNB coverage or the ng-eNB coverage, the UE may transmit a request for a sidelink resource for transmitting the HARQ feedback to the gNB or the ng-eNB. The UE transmitting the request for the sidelink resource for transmitting the HARQ feedback may include at least one of a UE transmitting a unicast-based V2X packet, a UE having received a unicast-based V2X packet, a scheduling UE, or an assistant UE. Signaling used by the UE to transmit a request for resources needed for HARQ feedback transmission may include at least one of an RRC dedicated message (SidelinkUEInformation or UEAsssitanceInformation) or MAC control signaling (HARQ feedback resource request MAC CE). The gNB or the ng-eNB having received the request may provide HARQ feedback transmission resource information to the UE through an RRC dedicated message (RRCConnectionReconfiguration). The HARQ feedback transmission resource information provided by the gNB or the ng-eNB may include at least one of a (model-based) HARQ feedback transmission resource to be scheduled directly by the gNB or the ng-eNB or a (mode2-based) HARQ feedback transmission resource to be selected by the UE. A procedure for granting a sidelink resource for HARQ feedback transmission will be described in detail with reference to <FIG>.

<FIG> illustrate a signal procedure in a sidelink resource grant mode <NUM> for direct communication between UEs, according to various embodiments of the disclosure.

<FIG> illustrate a procedure using SidelinkUEInformation signaling exchange according to various embodiments of the disclosure. In case that the UE transmits a SidelinkUEInformation message to the BS to request sidelink (SL) resources (including a V2X packet and an HARQ feedback), this case may include a case where the UE receives a System information message (e.g., sibTypeV2X) including information indicating that the BS supports a V2X sidelink function. In an embodiment of <FIG>, it may be assumed that UE1 is a transmission (TX) UE and UE2 is a reception (RX) UE. When unicast-based V2X packet transmission/reception is performed, the RX UE may transmit an HARQ feedback with respect to a V2X packet.

Referring to <FIG>, according to an embodiment of the disclosure, in operation <NUM>, UE1 may transmit a SidelinkUEInformation message including information needed to request an SL resource necessary for V2X packet transmission to a BS. In operation <NUM>, the BS may configure a sidelink transmission resource or SL resource to be used by UE1 for direct communication, based on information of UE1, and transmit an RRCConnectionReconfiguration message including the configured sidelink transmission resource to UE1. According to sidelink transmission resource grant information included in the RRCConnectionReconfiguration message received by the UE in operation <NUM>, when a sidelink resource grant mode for direct communication between UEs is determined as model where the BS directly schedules a sidelink resource and the UE is configured to request dynamic grant, then UE1 may transmit SL-BSR signaling to the BS to be dynamically granted with the sidelink transmission resource, in operation <NUM>. In operation <NUM>, the BS may dynamically grant the sidelink resource to be used for V2X packet transmission by UE1, based on information of SL-BSR signaling transmitted by UE1.

In an embodiment of the disclosure where UE1 and UE2 transmit and receive a V2X packet in the unicast manner, UE2 may transmit an HARQ feedback with respect to the V2X packet transmitted by UE1. In operation <NUM>, to be granted with a sidelink resource for HARQ feedback transmission, UE2 may transmit a SidelinkUEInformation message including information needed for HARQ feedback transmission resource grant to the BS. In operation <NUM>, the BS may configure a sidelink transmission resource to be used by UE2 for HARQ feedback transmission, based on information of UE2, and transmit an RRCConnectionReconfiguration message including the configured sidelink transmission resource to UE2. When the BS determines to directly schedule an HARQ feedback transmission resource according to sidelink resource grant information used for the HARQ feedback, included in the RRCConnectionReconfiguration message received in operation <NUM>, then UE2 may be granted with a sidelink resource to be used for HARQ feedback transmission from the BS in operation <NUM>.

Referring to <FIG>, according to an embodiment of the disclosure, in operation <NUM>, UE1 may transmit a SidelinkUEInformation message including information needed to request a sidelink resource necessary for V2X packet transmission to the BS. In operation <NUM>, the BS may configure a sidelink transmission resource to be used by UE1 for direct communication, based on information of UE1, and transmit an RRCConnectionReconfiguration message including the configured sidelink transmission resource to UE1. According to sidelink transmission resource grant information included in the RRCConnectionReconfiguration message received in operation <NUM>, when a sidelink resource grant mode for direct communication between UEs is determined as model where the BS directly schedules a sidelink resource and the UE is configured to request dynamic grant, then UE1 may transmit SL-BSR signaling to the BS to be dynamically granted with the sidelink transmission resource, in operation <NUM>. In operation <NUM>, the BS may dynamically grant the sidelink resource to be used for V2X packet transmission by UE1, based on information of SL-BSR signaling transmitted by UE1.

In an embodiment of the disclosure where UE1 and UE2 transmit and receive a V2X packet in the unicast manner, UE1 may transmit a request for grant of a sidelink resource needed by UE2 to transmit an HARQ feedback with respect to the V2X packet received by UE2. UE1 may transmit to the BS, information required for HARQ feedback transmission resource grant of UE2 through the SidelinkUEInformation message transmitted to be granted with the sidelink resource for HARQ feedback transmission in operation <NUM>. In operation <NUM>, the BS may configure the sidelink transmission resource for HARQ feedback transmission of UE2 and transmit the RRCConnectionReconfiguration message including sidelink transmission resource configuration information for the HARQ feedback to UE1. In operation <NUM>, UE1 may deliver the sidelink transmission resource configuration information for the HARQ feedback to UE2. An SL resource configuration message delivered from UE1 to UE2 in operation <NUM> may also include sidelink transmission resource configuration information to be used by UE1 for V2X packet transmission. When the BS determines to directly schedule an HARQ feedback transmission resource according to sidelink resource grant information used for the HARQ feedback, included in the RRCConnectionReconfiguration message received in operation <NUM>, then UE2 may be granted with a sidelink resource to be used for HARQ feedback transmission from the BS in operation <NUM>.

Referring to <FIG>, according to an embodiment of the disclosure, in operation <NUM>, UE1 may transmit a SidelinkUEInformation message including information needed to request an SL resource necessary for V2X packet transmission to the BS. In operation <NUM>, the BS may configure a sidelink transmission resource to be used by UE1 for direct communication, based on information of UE1, and transmit an RRCConnectionReconfiguration message including the configured sidelink transmission resource to UE1. According to sidelink transmission resource grant information included in the RRCConnectionReconfiguration message received in operation <NUM>, when a sidelink resource grant mode for direct communication between UEs is determined as model where the BS directly schedules a sidelink resource and the UE is configured to request dynamic grant, then UE1 may transmit SL-BSR signaling to the BS to be dynamically granted with the sidelink transmission resource, in operation <NUM>. In operation <NUM>, the BS may dynamically grant the sidelink resource to be used for V2X packet transmission by UE1, based on information of SL-BSR signaling transmitted by UE1.

In an embodiment of the disclosure where UE1 and UE2 transmit and receive a V2X packet in the unicast manner, UE1 may transmit a request for sidelink resource information needed by UE2 to the BS to transmit an HARQ feedback with respect to the V2X packet received by UE2. UE1 may transmit to the BS, information required for HARQ feedback transmission resource grant of UE2 through the SidelinkUEInformation message transmitted to be granted with the sidelink resource information for HARQ feedback transmission in operation <NUM>. In operation <NUM>, the BS may configure the sidelink transmission resource for HARQ feedback transmission of UE2 and transmit the RRCConnectionReconfiguration message including sidelink transmission resource configuration information for the HARQ feedback to UE1. In operation <NUM>, UE1 may deliver the sidelink transmission resource configuration information for the HARQ feedback to UE2. An SL resource configuration message delivered from UE1 to UE2 in operation <NUM> may also include sidelink transmission resource configuration information to be used by UE1 for V2X packet transmission. When the BS determines to directly schedule an HARQ feedback transmission resource according to sidelink resource grant information used for the HARQ feedback, included in the RRCConnectionReconfiguration message received in operation <NUM>, then UE2 may transmit SL-HARQ feedback request signaling to the BS to be granted with a sidelink resource for the HARQ feedback in operation <NUM>. In operation <NUM>, the BS may grant the sidelink resource to be used by UE2 for HARQ feedback transmission to UE2 based on received SL-HARQ feedback request signaling information. The SL-HARQ feedback request signaling may include at least one of a designation identification (ID), a source ID, a unicast session ID, or an SL configured grant ID.

In the above-described embodiment of <FIG>, the SidelinkUEInformation message transmitted by the UE to request a sidelink transmission resource may include at least one of the following parameters:.

In the above-described embodiment of <FIG>, information included in the RRCConnectionReconfiguration message used for delivery of sidelink RAT configuration information to the UE may include at least one of the following parameters:.

According to an embodiment of the disclosure, sidelink resource grant information transmitted through RRC dedicated signaling may be as below. <IMG>
<IMG>
<IMG>
<IMG>.

According to an embodiment of the disclosure, sidelink HARQ feedback resource grant information transmitted through RRC dedicated signaling may be as below. <IMG>
<IMG>
<IMG>
<IMG>.

According to an embodiment of the disclosure, the SL resource configuration message used to deliver sidelink resource configuration information for HARQ feedback transmission between UEs may include at least one parameter included in commTxFeedbackResources. According to an embodiment of the disclosure, the SL resource configuration message may include at least one parameter included in commTxResources.

When the UE is not located in a BS coverage, the UE may select an HARQ feedback transmission resource from a pre-configured resource. The pre-configured resource may be a pre-configured resource for the HARQ feedback or for the sidelink V2X packet and the HARQ packet.

In <FIG>, an SR resource for SL-BSR may have a configuration that is different from a resource for transmitting an uplink BSR. SR resource configuration information for transmitting SL-BSR may include at least one of SR resource ID, SR ID, Periodicity, offset, or PUCCH resource ID. The SR resource configuration information for transmitting SL-BSR may be differently managed according to service information of a sidelink V2X packet, QoS information, or priority information. The SR resource configuration information may be used mapped to an SL logical channel that may have a mapped QoS or priority.

According to an embodiment of the disclosure, a configuration of the SL logical channel may be as below. <IMG>
<IMG>
<IMG>.

<FIG> illustrate a procedure using UEAssistanceInformation signaling exchange according to various embodiments of the disclosure.

Referring to <FIG>, in case that the UE transmits a UEAssistanceInformation message to the BS to request sidelink (SL) resources (including a V2X packet and an HARQ feedback), this case may include a case where the UE receives a System information message (e.g., sibTypeV2X) including information indicating that the BS supports a V2X sidelink function. In an embodiment of <FIG>, it may be assumed that UE1 is a TX UE and UE2 is an RX UE. When unicast-based V2X packet transmission/reception is performed, the RX UE may transmit an HARQ feedback with respect to a V2X packet.

Referring to <FIG>, according to an embodiment of the disclosure, in operation <NUM>, UE1 may transmit a UEAssistanceInformation message including information necessary for sidelink V2X packet transmission resource grant to the BS. A request for a sidelink transmission resource based on the UEAssistanceInformation message may be used when the UE is granted with a sidelink transmission resource (a V2X packet or an HARQ feedback) by using at least one of SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM>). In operation <NUM>, the BS may configure a sidelink transmission resource or SL resource to be used by UE1 for direct communication, based on information of UE1, and transmit an RRCConnectionReconfiguration message including resource grant information to UE1. The RRCConnectionReconfiguration message may include at least one of SPS-based resource grant information, Configured Grant Type <NUM>-based resource grant information, or Configured Grant Type <NUM>-based resource grant information. In operation <NUM>, the BS may grant a sidelink transmission resource for V2X packet transmission of UE1. The sidelink transmission resource granted in operation <NUM> may support SPS, Configured Grant Type <NUM>-based, or Configured Grant Type <NUM>-based packet transmission.

In an embodiment of the disclosure where UE1 and UE2 transmit and receive a V2X packet in the unicast manner, UE2 may transmit an HARQ feedback with respect to the V2X packet transmitted by UE1. In operation <NUM>, to be granted with a sidelink resource for HARQ feedback transmission, UE2 may transmit a UEAssistanceInformation message including information needed for HARQ feedback transmission resource grant to the BS. A request for a sidelink HARQ feedback transmission resource based on the UEAssistanceInformation message may be used for HARQ feedback transmission with respect to V2X packet transmission/reception using at least one of SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM>. In operation <NUM>, the BS may configure a sidelink transmission resource to be used by UE2 for HARQ feedback transmission, based on information of UE2, and transmit an RRCConnectionReconfiguration message including the configured sidelink transmission resource to UE2. When the BS determines to directly schedule an HARQ feedback transmission resource according to sidelink resource grant information used for the HARQ feedback, included in the RRCConnectionReconfiguration message received in operation <NUM>, then UE2 may be granted with a sidelink resource to be used for HARQ feedback transmission from the BS in operation <NUM>.

In an embodiment of the disclosure where UE1 and UE2 transmit and receive a V2X packet in the unicast manner, UE1 may transmit a request for grant of a sidelink resource needed by UE2 to transmit an HARQ feedback with respect to the V2X packet received by UE2. UE1 may transmit to the BS, information required for HARQ feedback transmission resource grant of UE2 through the UEAssistanceInformation message transmitted to be granted with the sidelink resource for HARQ feedback transmission in operation <NUM>. A request for a sidelink HARQ feedback transmission resource based on the UEAssistanceInformation message may be used for V2X packet transmission/reception using at least one of SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM>. In operation <NUM>, the BS may configure the sidelink transmission resource for HARQ feedback transmission of UE2 and transmit the RRCConnectionReconfiguration message including sidelink transmission resource configuration information for the HARQ feedback to UE1. In operation <NUM>, UE1 may deliver the sidelink transmission resource configuration information for the HARQ feedback to UE2. An SL resource configuration message delivered in operation <NUM> may also include sidelink transmission resource configuration information to be used by UE1 for V2X packet transmission. When the BS determines to directly schedule an HARQ feedback transmission resource according to sidelink resource grant information used for the HARQ feedback, included in the RRCConnectionReconfiguration message received in operation <NUM>, then UE2 may be granted with a sidelink resource to be used for HARQ feedback transmission from the BS in operation <NUM>.

In another embodiment of the disclosure, to request a HARQ feedback transmission resource for a V2X packet transmitted based on SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM>, UE2 may transmit SL-HARQ feedback request grant signaling to the BS. SL-HARQ feedback request grant signaling may include at least one of destination ID, source ID, or sidelink configured grant ID (used as an identifier for identifying SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM>).

In an embodiment of <FIG>, the UEAssistanceInformation message used for V2X sidelink packet transmission resource or sidelink HARQ feedback transmission resource grant may include at least one of the following parameters:.

According to an embodiment of the disclosure, the above-described parameter values trafficPeriodicity, cgType1IntervalSL, and cgType2IntervalSL may be as below.

sym2, sym7, sym1×<NUM>, sym2x14, sym4x14, sym5x14, sym8x14, sym10x14, sym16x14, sym20x14, sym32x14, sym40x14, sym64x14, sym80x14, sym128x14, sym160x14, sym256x14, sym320x14, sym512x14, sym640x14, sym1024x14, sym1280x14, sym2560x14, sym5120x14, sym6, sym1×<NUM>, sym2x12, sym4x12, sym5x12, sym8x12, sym10x12, sym16x12, sym20x12, sym32x12, sym40x12, sym64x12, sym80x12, sym128x12, sym160x12, sym256x12, sym320x12, sym512x12, sym640x12, sym1280x12, sym2560x12.

The RRCConnectionReconfiguration message used for transmission of SPS-based, Configured Grant type <NUM>-based, or Configured Grant type <NUM>-based sidelink transmission resource grant information may include at least one of the following parameters:
<IMG>
<IMG>
CGType1-ConfigIndex ::=INTEGER (<NUM>. maxConfigCGType1).

CGType2-ConfigSL-ToAddModList ::= SEQUENCE (SIZE (<NUM>. maxConfigCGType2)) OF CGType2-ConfigSL.

CGType2-ConfigSL-ToReleaseList ::= SEQUENCE (SIZE (<NUM>. maxConfigCGType2)) OF CGType2-ConfigIndex
<IMG>
<IMG>
CGType2-ConfigIndex ::= INTEGER (<NUM>. maxConfigCGType2).

HARQ feedback resource grant information for V2X sidelink packet transmission based on SPS, Configured Grant type <NUM>, or Configured Grant type <NUM> may include at least one of the following information:
information of commTxFeedbackResources, HARQ feedback resource pattern, start time, feedback resource period, resource time info, resource frequency info, HARQ feedback UE ID, MCS.

Referring to various embodiments of the disclosure shown in <FIG>, a description will be made of a case where the UE grants the sidelink transmission resource (V2X packet or HARQ feedback) without intervention of the BS. A case where the UE grants a sidelink transmission resource without intervention of the BS may correspond to a case where the BS sets through the RRCConnectionReconfiguration message, a mode (mode2) in which the UE schedules sidelink V2X packet transmission resource grant or sidelink HARQ feedback transmission resource grant, or a case where the UE determines to perform an operation of mode2 in the embodiment of <FIG>.

<FIG> and <FIG> illustrate an example of a sidelink resource grant mode 2a where the UE grants a sidelink transmission resource (V2X packet or HARQ feedback) to be used to itself, <FIG> illustrate an example of a sidelink resource grant mode 2c where the UE grants a sidelink transmission resource based on a configured grant type, <FIG> and <FIG> illustrate an example of a sidelink resource grant mode 2d where the UE grants a sidelink transmission resource of another UE, and <FIG> illustrates an example of a sidelink resource grant mode 2b where the UE assists sidelink transmission resource grant of another UE.

<FIG> and <FIG> illustrate a signal procedure in a sidelink resource grant mode 2a for direct communication between UEs, according to various embodiments of the disclosure. In an embodiment of <FIG> and <FIG>, it may be assumed that UE1 is a TX UE and UE2 is an RX UE.

Referring to <FIG>, in operation <NUM>, a setup procedure for transmitting/receiving a unicast-based V2X sidelink packet between UE1 and UE2 may be performed. Operation <NUM> may be performed when UE1 and UE2 perform unicast-based V2X sidelink packet transmission/reception. When UE1 and UE2 perform broadcast-based V2X sidelink packet transmission/reception, operation <NUM> may not be performed. UE1 may select a sidelink resource to be used for V2X packet transmission, in operation <NUM>. UE1 may sense a sidelink resource configured by the UE for mode <NUM> or mode 2a through RRC dedicated signaling or a pre-configured sidelink resource and grant the sidelink resource. In operation <NUM>, a sidelink transmission resource granted by UE1 may include at least one of a dynamic resource grant (one shot grant), a Configured Grant Type <NUM> grant, or a Configured Grant Type <NUM> grant. The sidelink transmission resource granted by UE1 may support V2X service information, i.e., at least one of service ID, application ID, destination ID, source ID, QoS information, priority information, traffic pattern information, or HARQ feedback capability. The HARQ feedback capability may include at least one of UE2's HARQ timing (a time required for HARQ feedback transmission after V2X packet transmission), an RF configuration, or an antenna configuration. When unicast-based V2X packet transmission/reception is performed, UE1 may share the granted sidelink transmission resource (an SL grant or an SL resource pool) to UE2. When unicast-based V2X packet transmission/reception is performed, UE2 may transmit an HARQ feedback with respect to a V2X packet. UE2 may grant a sidelink resource necessary for HARQ feedback transmission to itself, in operation <NUM>. UE2 may select an HARQ feedback transmission resource by considering its HARQ feedback capability. The HARQ feedback transmission resource granted by UE2 may support V2X service information, i.e., at least one of service ID, application ID, destination ID, source ID, QoS information, priority information, traffic pattern information, or HARQ feedback capability. UE2 may select the HARQ feedback transmission resource corresponding to a V2X packet transmission resource granted by UE1. UE2 may share the HARQ feedback transmission resource granted in operation <NUM> with UE1.

Referring to <FIG>, in operation <NUM>, a setup procedure for transmitting/receiving a unicast-based V2X sidelink packet between UE1 and UE2 may be performed. Operation <NUM> may be performed when UE1 and UE2 perform unicast-based V2X sidelink packet transmission/reception. When UE1 and UE2 perform broadcast-based V2X sidelink packet transmission/reception, operation <NUM> may not be performed. UE1 may select a sidelink resource to be used for V2X packet transmission, in operation <NUM>. UE1 may sense a sidelink resource configured by the UE for mode <NUM> or mode 2a through RRC dedicated signaling or a pre-configured sidelink resource and grant the sidelink resource. In operation <NUM>, a sidelink transmission resource granted by UE1 may include at least one of a dynamic resource grant (one shot grant), a Configured Grant Type <NUM> grant, or a Configured Grant Type <NUM> grant. The sidelink transmission resource granted by UE1 may support V2X service information, i.e., at least one of service ID, application ID, destination ID, source ID, QoS information, priority information, traffic pattern information, or HARQ feedback capability. The HARQ feedback capability may include at least one of UE2's HARQ timing (a time required for HARQ feedback transmission after V2X packet transmission), an RF configuration, or an antenna configuration. When unicast-based V2X packet transmission/reception is performed, UE1 may grant the HARQ feedback transmission resource to UE2 according to UE2's HARQ feedback capability in operation <NUM>. UE1 may share the granted sidelink transmission resource (an SL grant or an SL resource pool) or HARQ feedback transmission resource with UE2 in operation <NUM>. UE2 may transmit an HARQ feedback by using the HARQ feedback transmission resource granted by UE1.

In the embodiment of <FIG> and <FIG>, information of the sidelink packet transmission resource or the sidelink HARQ feedback transmission resource, shared between UE1 and UE2, may be as below.

The information of the sidelink packet transmission resource may include at least one of an ue-Selected information element (IE) of commTxResources of RRCConnectionReconfiguration, CGType1-Config IE, or CGType2-Config IE.

The information of the sidelink HARQ feedback transmission resource may include at least one of an ue-Selected IE of commTxFeedbackResources of RRCConnectionReconfiguration, harqFeedback IE of CGType1-Config, or harqFeedback IE of CGType2-Config.

<FIG> illustrate a signal procedure in a sidelink resource grant mode 2c for direct communication between UEs, according to various embodiments of the disclosure;.

In an embodiment of <FIG>, it may be assumed that UE1 is a TX UE and UE2 is an RX UE. Although various embodiments of <FIG> will be described based on Configured Grant Type <NUM> configuration information, they may also be equally applied when SPS or Configured Grant Type <NUM> configuration information is used. The configuration information may include one or more pattern information of SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM>. The pattern information may be made based on at least one of traffic periodicity, timing offset, service ID, QoS information, priority information, or a message size of a V2X packet using SPS, CGType1, or CGType2. The pattern information may be managed by a BS or V2X server for each mobile network operator (MNO) network or automatic original equipment manufacturer (OEM) and provided to a UE. In an embodiment of the disclosure, a UE may obtain configuration information of at least one of sidelink SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM> from a BS.

Referring to <FIG>, in operation <NUM>, a setup procedure for transmitting/receiving a unicast-based V2X sidelink packet between UE1 and UE2 may be performed. Operation <NUM> may be performed when UE1 and UE2 perform unicast-based V2X sidelink packet transmission/reception. In operation <NUM>, UE1 may receive the Configured Grant Type <NUM> configuration information and obtain pattern information of CGType <NUM>. The CGType <NUM> pattern information of the Configured Grant type <NUM> configuration information may include information of an SL CG Type <NUM> configuration (CGType1_ConfigSL) IE of <FIG>. In operation <NUM>, UE1 may select a CGType <NUM> pattern based on traffic attributes of a V2X packet to be transmitted.

When one CGType <NUM> pattern is configured in operation <NUM>, the configured CGType <NUM> pattern may be used. For unicast-based V2X packet transmission/reception, UE1 may determine the CGType <NUM> pattern based on exchange of V2X traffic pattern and HARQ feedback capability information between UE1 and UE2. When one or more patterns are configured in operation <NUM>, UE1 may monitor a sidelink resource of each pattern and select a pattern having the lowest congestion ratio or a congestion ratio that is less than a threshold. The threshold for the congestion ratio used for pattern selection may be preset for V2X service type, QoS info, or priority info (information configured by the BS or pre-configured information). Information about a time for performing sidelink resource monitoring of the pattern (a sensing period or a sensing interval) may be information configured by the BS or pre-configured information. When UE1 and UE2 perform unicast-based V2X packet transmission/reception, UE1 may deliver the CGType <NUM> pattern information selected in operation <NUM> to UE2, in operation <NUM>. UE2 may obtain V2X packet transmission resource grant and HARQ feedback transmission resource grant information from the CGType <NUM> pattern information received in operation <NUM>. In operation <NUM>, UE2 may select a HARQ feedback transmission resource to correspond to the CGType1 pattern selected by UE1.

According to an embodiment of the disclosure, a scheme for UE2 to select the HARQ feedback transmission resource in operation <NUM> may be as below.

Mapping information between the CGType <NUM> pattern and the HARQ feedback transmission resource corresponding thereto may be delivered from the BS to UE1. The mapping information may be delivered from UE1 to UE2. The mapping information may be configured as a pre-configuration parameter. The HARQ feedback transmission resource may be defined to correspond to each Configured Grant Type <NUM> pattern. The mapping information may include an HARQ feedback transmission resource pattern mapped to each CGType <NUM> transmission resource pattern. For example, the mapping information may include at least one of a pattern ID, a CGType <NUM> pattern, or an HARQ feedback pattern as below. When UEs performing unicast-based V2X packet transmission/reception are aware of a mapping information list between CGType <NUM> patterns and corresponding HARQ feedback patterns and manage the mapping information list in the form of indices (pattern IDs), then V2X packet transmission resources for unicast packet transmission between UE1 and UE2 and HARQ feedback transmission resources may be exchanged as mapping information indices.

According to another embodiment of the disclosure, the BS may select CGType <NUM> pattern information to be used by UE1 in operation <NUM>, and grant the selected CGType <NUM> pattern information to UE1 through RRCConnectionConfiguration. UE1 may select a V2X packet transmission resource from the CGType <NUM> pattern granted by the BS in operation <NUM>. UE1 may select the V2X packet transmission resource by using a sensing procedure.

Referring to <FIG>, in operation <NUM>, a setup procedure for transmitting/receiving a unicast-based V2X sidelink packet between UE1 and UE2 may be performed. Operation <NUM> may be performed when UE1 and UE2 perform unicast-based V2X sidelink packet transmission/reception. UE1 may transmit a UEAssistanceInformation message or a SidelinkUEInformation message to the BS in operation <NUM>. UEAssistanceInformation or SidelinkUEInformation may provide information used by the BS to configure CGType <NUM> pattern information, and may include at least one of UEAssistanceInformation or SidelinkUEInformation of <FIG>. In the remaining procedure of <FIG>, operations <NUM>, <NUM>, <NUM>, and <NUM> of UE1 and UE2 may be the same as those of UE1 and UE2 in the above-described embodiment of <FIG>.

In another embodiment of the disclosure, a UE may obtain configuration information of at least one of sidelink SPS, Configured Grant Type <NUM>, or Configured Grant Type <NUM> from a pre-configured pre-configuration parameter.

Referring to <FIG>, in operation <NUM>, a setup procedure for transmitting/receiving a unicast-based V2X sidelink packet between UE1 and UE2 may be performed. Operation <NUM> may be performed when UE1 and UE2 perform unicast-based V2X sidelink packet transmission/reception. UE1 may obtain the CGType <NUM> pattern configuration information from the pre-configuration parameter. A criterion for UE1 to select the CGType <NUM> pattern information may include at least one of a service ID, QoS Info, or priority Info of a V2X packet to be transmitted by UE1, traffic pattern information, or HARQ feedback capability. In the remaining procedure of <FIG>, operations <NUM>, <NUM>, <NUM>, and <NUM> of UE1 and UE2 may be the same as those of UE1 and UE2 in the above-described embodiment of <FIG>.

When UEs performing unicast-based V2X packet transmission/reception are aware of a CGType <NUM> pattern list, an HARQ feedback pattern list corresponding thereto, and mapping index information, the UEs may use mapping index information to indicate that the CGType <NUM> pattern to be used for V2X packet transmission/reception is changed.

Referring to <FIG>, in operation <NUM>, a setup procedure for transmitting/receiving a unicast-based V2X sidelink packet between UE1 and UE2 may be performed. Operation <NUM> may be performed when UE1 and UE2 perform unicast-based V2X sidelink packet transmission/reception. Operations <NUM> through <NUM> may be the same as a procedure for exchanging a CGType <NUM> pattern to be used for unicast-based V2X packet transmission/reception described in <FIG> and corresponding HARQ feedback pattern. UE1 may determine to change the CGType <NUM> pattern to be used for unicast-based V2X packet transmission/reception with UE2, in operation <NUM>. UE1 may transmit pattern ID information corresponding to the changed CGType <NUM> to UE2 through SL resource configuration signaling, in operation <NUM>. UE2 may select an HARQ feedback pattern corresponding to a pattern ID corresponding to the changed CGType <NUM>, in operation <NUM>. The SL resource configuration signaling transmitted in operation <NUM> may include at least one of PC5 RRC, PC5 signaling, or PC5 MAC CE.

<FIG> and <FIG> illustrate a signal procedure in a sidelink resource grant mode 2d for direct communication between UEs, according to various embodiments of the disclosure.

<FIG> illustrates a procedure for selecting a scheduling UE (playing a role in grating a sidelink transmission resource to another UE), according to an embodiment of the disclosure. Referring to <FIG>, UE1 may transmit its V2X information to a V2X server in operation <NUM>. V2X information may include at least one of V2X service ID (application ID), location info, or V2X capability (non-3GPP based V2X protocol support, RF capability, antenna capability, power capability). In operation <NUM>, the V2X server may select a UE that is to be in charge of the scheduling UE. To select the UE as the scheduling UE, information to be obtained by the V2X server or the BS may be as below.

UE supporting a non-3GPP-based V2X protocol (e.g., dedicated short range communications (DSRC)) (UE capable of determining interference and collision with a non-3GPP-based V2X technology and granting a resource having a low possibility of interference to another UE when the non-3GPP-based V2X technology and a sidelink resource are shared);.

UE in a gNB coverage (UE capable of granting a sidelink resource for the advanced service by supporting an NR-V2X protocol);.

UE supporting a sidelink resource sensing function (UE capable of granting a resource of P-UE having no sidelink resource sensing function); and
location information (information needed to manage a sidelink resource pool to be used by a scheduling UE, based on a zone/an area/a geo network).

The V2X server may perform signaling indicating that UE1 is selected as the scheduling UE to UE1, in operation <NUM>. Signaling for indicating the scheduling UE in operation <NUM> may include at least one of the following information:.

In operation <NUM>, UE1 selected as the scheduling UE may play a role as the scheduling UE. To obtain capabilities of a TX UE and an RX UE that are to use sidelink resources (V2X packet transmission and HARQ feedback transmission), the scheduling UE may perform a capability negotiation procedure with the TX UE and the RX UE.

In an embodiment of <FIG>, a BS may be used instead of the V2X server, and signaling between UE1 and the BS may be replaced with RRC signaling.

While a description has been made with reference to <FIG> of an example where the V2X server or the BS determines the scheduling UE, for unicast-based V2X packet transmission/reception, negotiation may be performed such that one of two UEs functions as the scheduling UE.

<FIG> illustrates a procedure for obtaining information needed for the scheduling UE to schedule a sidelink transmission resource for another UE. Referring to <FIG>, in operation <NUM>, a PC5 unicast connection setup procedure may be performed when UE2 and UE3 transmit and receive a unicast-based V2X sidelink packet. Operation <NUM> may be performed when UE2 and UE3 perform unicast-based V2X sidelink packet transmission/reception. In operations <NUM> through <NUM>, UE2 or UE3 may obtain information of a scheduling UE that is to grant sidelink resources to be used for V2X packet transmission or HARQ feedback transmission. The information of the scheduling UE may be obtained using at least one of V2X signaling from the V2X server, RRC signaling transmitted from the BS, PC5 signaling (PC5 RRC or PC5 PHY preamble) transmitted by the scheduling UE, or pre-configuration. The scheduling UE may be configured differently for each V2X service, each V2X transmission mode (unicast, groupcast, or broadcast), each zone ID, or each location of UE2 or UE3. In operation <NUM>, UE2 or UE3 may deliver V2X capability information to the scheduling UE. The V2X capability information may be delivered for each V2X service, each V2X transmission mode, each zone ID, or each location. In operation <NUM>, the scheduling UE may schedule the V2X packet transmission resource or the HARQ feedback transmission resource based on the V2X capability of UE2 or UE3.

In an embodiment of the disclosure shown in <FIG>, information exchanged between UE2 and UE3 may include at least one of SidelinkUEInformation or UEAssistanceInformation or information included in RRCConnectionReconfiguration. When a CGType-based transmission resource grant mode is used, the scheduling UE may select and grant a pattern. When a CGType-based transmission resource grant mode is used, the scheduling UE may set a pattern for a UE.

<FIG> and <FIG> illustrate a signal procedure in a sidelink resource grant mode 2b for direct communication between UEs, according to various embodiments of the disclosure.

<FIG> illustrates a procedure for selecting an assistant UE (playing a role in assisting another UE in granting a sidelink transmission resource), according to an embodiment of the disclosure. The assistant UE needs to have capabilities to perform at least roles described below. Capability information of the assistant UE provided below may be delivered to the V2X server, the base station, or the scheduling UE.

The assistant UE may provide a UE to be granted with a sidelink transmission resource with information about a sidelink transmission resource pool from which the resource is to be selected.

The assistant UE may monitor a congestion ratio of a transmission resource pool and provide a pool having a low congestion ratio to another UE. The assistant UE may obtain a congestion ratio reference value corresponding to QoS or priority information required by a V2X packet.

The assistant UE may sense a transmission resource pool for a UE having no sensing function despite needing resource grant, and provide a transmission resource pool to be used for the UE having no sensing function.

The assistant UE may support a V2X protocol (e.g., LTE-V2X) of a previous version, monitor a resource pool when a sidelink transmission pool has to be shared with the V2X protocol of the previous version, select a resource pool having a low congestion ratio, and provide the selected resource pool to another UE.

The assistant UE may monitor a resource pool by using a non-3GPP-based V2X protocol when a sidelink transmission pool has to be shared with the non-3GPP-based V2X protocol, select a resource pool having a low congestion ratio, and provide the selected resource pool to another UE.

The assistant UE may monitor a resource pool instead of another UE that is not capable of supporting sidelink resource sensing provided in an E-UTRA system or sidelink resource sensing provided in an NGRA system, select a resource pool, and provide the selected resource pool to another UE.

The assistant UE may have a capability to determine Configured Grant Type-based sidelink resource grant or one-shot grant. The Configured Grant Type-based sidelink resource grant may have a capability to select a pattern. When CGType pattern selection is performed, a pattern-specific sidelink resource congestion ratio corresponding to a QoS level required by another UE may be measured.

The assistant UE may deliver SidelinkUEInformation or UEAssistanceInformation information of another UE to the scheduling UE.

The assistant UE may have to set PC5 RRC or PC5 signaling with the scheduling UE or another UE.

The assistant UE may be a UE in a gNB coverage. (UE may be capable of granting a sidelink resource for the advanced service by supporting an NR-V2X protocol).

The assistant UE may be selected as the same UE as the scheduling UE of <FIG> and <FIG>. The assistant UE may be selected by the V2X server or the BS based on location information (for example, an RSU UE installed around a crosswalk may be selected). A leader of a platoon service group may be selected as the assistant UE.

Referring to <FIG>, UE1 may transmit its V2X information in operation <NUM>. V2X information may include at least one of V2X service ID (application ID), location information, or V2X capability (non-3GPP based V2X protocol support, RF capability, antenna capability, power capability). In operation <NUM>, the V2X server may select a UE that is to be in charge of the scheduling UE. To select the UE as the assistant UE, information to be obtained by the V2X server or the BS may be the same as the capability information. In operation <NUM>, the V2X server may perform signaling indicating that UE1 is selected as the assistant UE to UE1. Signaling for indicating the assistant UE in operation <NUM> may include at least one of the following information:
sidelink transmission resource to be used by the assistant UE (a V2X packet or an HARQ feedback), V2X resource pool configuration, or V2X service information (service ID, destination ID, source ID).

In operation <NUM>, UE1 may play a role as the assistant UE. To obtain capabilities of a TX UE and an RX UE that are to use sidelink resources (V2X packet transmission and HARQ feedback transmission), the assistant UE may perform a capability negotiation procedure with the TX UE and the RX UE. The assistant UE may perform a capability negotiation procedure with the scheduling UE to assist scheduling of the scheduling UE.

<FIG> illustrates a procedure for obtaining information needed for the assistant UE to assist sidelink transmission resource grant for another UE.

Referring to <FIG>, in operation <NUM>, a PC5 unicast connection setup procedure may be performed when UE2 and UE3 transmit and receive a unicast-based V2X sidelink packet. Operation <NUM> may be performed when UE2 and UE3 perform unicast-based V2X sidelink packet transmission/reception. In operations <NUM> through <NUM>, UE2 or UE3 may obtain information of the assistant UE that is to assist grant of sidelink resources to be used for V2X packet transmission or HARQ feedback transmission. The information of the assistant UE may be obtained using at least one of V2X signaling from the V2X server, RRC signaling transmitted from the BS, PC5 signaling (PC5 RRC or PC5 PHY preamble) transmitted by the assistant UE, or pre-configuration. The assistant UE may be configured differently for each V2X service, each V2X transmission mode (unicast, groupcast, or broadcast), each zone ID, or each location of UE2 or UE3.

In operation <NUM>, UE2 or UE3 may deliver V2X capability information to the assistant UE. The V2X capability information may be delivered for each V2X service, each V2X transmission mode, each zone ID, or each location. In operation <NUM>, the assistant UE may assist grant of the V2X packet transmission resource or the HARQ feedback transmission resource by UE2 or UE3, based on the V2X capability of UE2 or UE3. The assistant UE may obtain scheduling UE information of UE2 or UE3, and the scheduling UE may report grant of the V2X packet transmission resource or the HARQ feedback transmission resource by UE2 or UE3. The scheduling UE information by UE2 or UE3 may be obtained in the capability negotiation procedure with UE2 or UE3 or from the BS or the V2X server. In an embodiment of the disclosure shown in <FIG>, information exchanged between the assistant UE and the scheduling UE, UE2, or UE3 may include at least one of SidelinkUEInformation or UEAssistanceInformation or information included in RRCConnectionReconfiguration. When the assistant UE assists the CGType-based transmission resource grant, the assistant UE may select and provide a pattern.

<FIG> illustrate a signal procedure for operating sidelink resource configuration information for direct communication between UEs, according to various embodiments of the disclosure.

Referring to <FIG>, when a UE moves while obtaining V2X sidelink resource configuration information, the UE needs to identify validity of the resource configuration information. For example, when a service operated by the same automotive OEM is executed except for when the UE moves in a network operated by the same mobile operator, the same resource configuration information may be used regardless of whether the UE moves between cells or BSs. In another embodiment of the disclosure, to prevent a congestion ratio of resource use, a resource may be managed to use the same resource configuration information or different resource configuration information for each location (geo, area, or zone). According to various embodiments of the disclosure, a description will be made with reference to <FIG> of an example where to determine whether the V2X sidelink resource configuration information is valid, the UE is in an idle state, in an inactive state, in a connected state, or out of coverage.

<FIG> illustrates an example of a procedure for identifying validity of the V2X sidelink resource configuration information by the UE in the idle state or the in the inactive state.

Referring to <FIG>, in operation <NUM>, the UE may identify the validity of a V2X system information block(sibTypeV2X) stored in the UE, by receiving system information block (SIB) information including V2X configuration validity information. sibTypeV2X may include V2X sidelink resource configuration information available to the UE. The V2X configuration validity information may include a V2XareaScope parameter or a systemInformationV2XAreaID parameter. <IMG>
<IMG>.

Cond 'V2X-AREA-ID' - The field is mandatory present if systemInformationV2XAreaID is present and the SIB is valid within the area identified by systemInformationV2XAreaID, otherwise it is not present.

The area may include at least one of an area ID, a list of Cell(s), a list of RAN area IDs, or a list of TA IDs.

In operation <NUM>, the UE may identify a value of a V2XareaScope parameter and determine that sibTypeV2X of the UE is valid when the value of the V2XareaScope parameter is true. When the value of the V2XareaScope parameter is false, the UE may determine that sibTypeV2X is invalid. When the UE determines that the value of the V2XareaScope parameter is false, the UE may receive sibTypeV2X and obtain the V2X sidelink resource configuration information in operations <NUM> through <NUM>.

According to an embodiment of the disclosure, an operation, performed by the UE, of identifying validity of sibTypeV2X by using V2XareaScope and systemInformationV2XAreaID may be as described below. <NUM>> for each stored version of a SIB:
<NUM>> if the V2XareaScope value of the stored version of the SIB is the same as the value received from the serving cell:.

<FIG> illustrates an example of a procedure for identifying validity of the V2X sidelink resource configuration information by the UE in the connected state.

Referring to <FIG>, in operation <NUM>, the UE may receive a parameter indicating validity of V2X sidelink resource configuration information being used in a serving cell through a HO-CMD message indicating a handover to a target cell. Identification of the validity of the V2X sidelink resource configuration information may use a signaling procedure between a serving cell and a target cell in operation <NUM>. In operation <NUM>, a parameter used to identify the validity of the V2X sidelink resource configuration information through the HO-CMD message may include a <NUM>-bit V2X configuration validity indicator or a V2X configuration validity indication bitmap. When the V2X configuration validity indicator is set to <NUM>, the UE may determine that the V2X sidelink resource configuration information being used in the serving cell is available to the target cell. The V2X configuration validity indication bitmap may be used to identify the validity of each of several V2X sidelink resource configuration parameters. When the V2X configuration validity indication bitmap is set to <NUM>, the UE may determine that the V2X sidelink resource configuration parameter being used in the serving cell is available to the target cell. When the V2X configuration validity indicator or a bit value of the V2X configuration validity indication is set to <NUM>, the UE may obtain again the V2X sidelink resource configuration information or resource configuration parameter from the target cell. The V2X sidelink resource configuration information or parameter determined to be invalid may be obtained through RRC dedicated signaling received from the target cell as in operations <NUM> and <NUM>.

<FIG> illustrates another example of a procedure for identifying validity of the V2X sidelink resource configuration information by the UE in the connected state.

Referring to <FIG>, in operation <NUM>, the UE may receive a parameter indicating validity of V2X sidelink resource configuration information being used in a serving cell through a HO-CMD message indicating a handover to a target cell. Identification of the validity of the V2X sidelink resource configuration information may use a signaling procedure between a serving cell and a target cell in operation <NUM>. In operation <NUM>, a parameter used by the UE to determine the validity of the V2X sidelink resource configuration information in the HO-CMD message may include dedicatedSIB.

According to an embodiment of the disclosure, dedicatedSIB parameter information included in the HO-CMD message may be as below.

When dedicatedSIB sibTypeV2X is included in the HO-CMD message, the UE may use the V2X sidelink resource configuration information provided in sibTypeV2X in the target cell.

In another example of a parameter available for identifying the validity of the V2X sidelink resource configuration information, the HO-CMD message may include an area ID. Area ID information may be used to use different area IDs for a V2X configuration set or respective V2X configurations, and when the UE determines that an area ID for a V2X configuration set or each V2X configuration being used in the serving cell is changed in the target cell (i.e., the same area ID as in the serving cell is not set), the UE may obtain again V2X sidelink resource configuration information provided through RRC dedicated signaling from the target cell.

According to an embodiment of the disclosure, an IE notifying area ID information with a valid V2X configuration may be as below. <IMG>
<IMG>.

<FIG> illustrates an example of a procedure for identifying validity of the V2X sidelink resource configuration information by the UE out of a coverage.

Referring to <FIG>, out of the coverage, the UE may perform V2X packet transmission/reception by using pre-configured V2X sidelink resource configuration information. An example of a scenario to identify the validity of the pre-configured V2X sidelink resource configuration information may be as below. The V2X service may be used at <NUM> in an area A, and the V2X service may be used at <NUM> in an area B. The V2X configuration of <NUM> and the V2X configuration of <NUM> may be configured differently. When the UE moves between zones corresponding to the area A, the <NUM> V2X configuration corresponding to the area A may be maintained. When the UE moves between zones corresponding to the area B, the <NUM> V2X configuration corresponding to the area B may be maintained.

Referring to <FIG>, in operation <NUM>, The UE may calculate a zone ID for a zone where the UE is currently located. The zone ID of the UE may be calculated as follows: <MAT> <MAT> <MAT>.

In operation <NUM>, the UE may determine whether the zone ID is included in the area ID being used. The zone ID and area ID information mapped thereto may be provided through a pre-configured pre-configuration parameter. When the UE determines that the current zone ID is not included in the area ID being used, the UE may obtain and use a pre-configuration parameter corresponding to the changed area ID, in operation <NUM>.

According to an embodiment of the disclosure, pre-configured V2X sidelink resource configuration information and information indicating validity of the resource configuration information, i.e., a zone ID and area ID information mapped thereto may be as below. <IMG>
<IMG>
<IMG>
<IMG>.

An apparatus and method according to various embodiments of the disclosure may provide a method of supporting a vehicle communication service requiring various QoSs in a vehicle communication system by granting sidelink resources to be used for direct communication between UEs, thereby achieving required values for reliability and low-latency in vehicle communication.

In addition, effects obtainable in the disclosure are not limited to the effects as described above, and other effects not described above will become apparent to those skilled in the art from the following detailed description.

Claim 1:
A method, performed by a user equipment, UE (<NUM>), of performing sidelink communication, the UE (<NUM>) being in idle or inactive state, the method comprising:
obtaining a valid system information block, SIB, for a vehicle-to-everything, V2X, sidelink communication;
autonomously determining a sidelink resource, based on information of a pool of sidelink resources included in the valid SIB for the V2X sidelink communication; and
performing sidelink communication with another UE (<NUM>) using the determined sidelink resource,
wherein the obtaining the valid SIB for the V2X sidelink communication comprises:
receiving, from a base station (<NUM>), a SIB including information for determining a validity of a stored SIB for the V2X sidelink communication, wherein the information for determining the validity of the stored SIB includes an area scope parameter, a system information area identification, ID, for a serving cell, and a value tag, and wherein the area scope parameter, system information area ID and the value tag are associated with a SIB for the V2X sidelink communication;
determining the validity of the stored SIB for the V2X sidelink communication, based on the information for determining the validity of the stored SIB for the V2X sidelink communication, wherein the stored SIB is considered as the valid SIB in case that an area scope parameter of the stored SIB is the same as the area scope parameter of the received SIB, and that a first PLMN identity included in a PLMN identity information list, the system information area ID included in the received SIB, and the value tag included in the received SIB are identical to a PLMN identity, a system information area ID and a value tag that are associated with the stored SIB, respectively; and
receiving, from the base station, the valid SIB for the V2X sidelink communication in case that the stored SIB for the V2X sidelink communication is determined to be invalid.