Patent Description:
To meet the demand for wireless data traffic having increased since the deployment of fourth generation (<NUM>) communication systems, efforts have been made to develop an improved fifth generation (<NUM>) or pre-<NUM> communication system, also referred to as a beyond <NUM> network" or a post long term evolution (LTE) system.

The <NUM> communication system is considered to be implemented in higher frequency millimeter wave (mmWave) bands, e.g., <NUM> bands, so as to accomplish higher data rates.

In addition, development for system network improvement in <NUM> communication systems is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, and coordinated multi-points (CoMP), reception-end interference cancellation, for example.

In the <NUM> system, hybrid frequency shift keying (FSK), quadrature amplitude modulation (QAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have also been developed.

The <NUM> system is considering supports for more various services as compared to the conventional <NUM> system. For example, the most representative service may include an ultrawide band mobile communication service (enhanced mobile broad band (eMBB)), an ultrahigh reliable/low latency communication service (ultra-reliable and low latency communication (URLLC)), a massive device-to-device communication service (massive machine type communication (mMTC)), and a next-generation broadcast service (evolved multimedia broadcast/multicast service (eMBMS)). A system providing the URLLC service may be referred to as a URLLC system, and a system providing the eMBB service may be referred to as an eMBB system. The terms "service" and "system" may be interchangeably used.

Among these services, the URLLC service that is a new service under consideration in the <NUM> system in contrast to the existing <NUM> system requires ultrahigh reliability, such as a packet error rate of about <NUM>% and low latency, such as about <NUM> milliseconds (msec), as compared to the other services. To meet these strict conditions, the URLLC service may need to apply a shorter transmission time interval (TTI) than the eMBB service, and various operating schemes employing the same are now under consideration.

The Internet is now evolving to the Internet of things (IoT) where distributed entities, such as things, exchange and process information without human intervention. As technology elements, such as "sensing technology", "wired/wireless communication and network infrastructure", "service interface technology", and "security technology" have been demanded for IoT implementation, a sensor network, a machine-to-machine (M2M) communication, and machine type communication (MTC) have been recently researched.

IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing information technology and various industrial applications.

<CIT> discloses a method and an apparatus for indicating device-to-device (D2D) related information in a wireless communication system. <CIT> discloses a method for establishing layer-<NUM> entities for a D2D communication system. <CIT> discloses a V2X communication method. <CIT> discloses relates to resource configurations and scheduling of direct transmissions in multi-network environments. The publication "<NPL>) provides a text proposal to TR <NUM>. The publication "<NPL>) proposes to use a SidelinkUEInformation message for indicating information about the expected V2X traffic to the gNB.

Accordingly, various attempts have been made to apply <NUM> communication systems to IoT networks. Application of a cloud RAN as the above-described big data processing technology may also be considered an example of convergence of <NUM> with IoT.

In a <NUM> system, wireless interface schemes for providing services meeting various levels of quality of service (QoS) are being researched. For example, a direct communication scheme for a vehicle-to-everything (V2X) user equipment (UE) has been proposed. V2X refers to all types of communication schemes that can be applied to road vehicles, and various additional services, beyond an initial safety application, have become possible through convergence with recently developed wireless communication technology. However, there is a need in the art to further decrease a communication time, increase reliability, and more efficiently support direct communication between UEs.

According to a first aspect, the present invention provides a method by a first user equipment (UE) in a wireless communication system as defined by the subject-matter of independent claim <NUM>.

According to a second aspect, the present invention provides a method by a base station (BS) in a wireless communication system as defined by the subject-matter of independent claim <NUM>.

According to a third aspect, the present invention provides a first user equipment (UE) as defined by the subject-matter of independent claim <NUM>.

According to a fourth aspect, the present invention provides a base station (BS) as defined by the subject-matter of independent claim <NUM>.

Accordingly, an aspect of the disclosure is to provide an apparatus and a method for supporting a vehicle communication service and data transmission that achieve a required high-reliability and low-latency value by providing a method of performing communication through a direct communication scheme between UEs in a vehicle communication system.

Another aspect of the disclosure is to provide a method of supporting a vehicle communication service that requires various levels of quality of service (QoS) through direct communication between UEs and a method of configuring an RLC function parameter used for direct communication between UEs in a vehicle communication system, thereby achieving a required high-speed, high-reliability, and low-latency value.

This embodiment is however not covered by the claims. [Mode for the Invention].

Hereinafter, embodiments of the disclosure may be described with reference to accompanying drawings. Accordingly, those of ordinary skill in the art will recognize that modifications, and/or alternatives on the embodiments described herein can be variously made without departing from the scope of the disclosure. With regard to description of drawings, similar components may be marked by similar reference numerals. Descriptions of well- known functions and/or configurations will be omitted for the sake of clarity and conciseness.

The terms used in the disclosure are only used to describe specific embodiments and are not intended to limit the disclosure. A singular expression may include a plural expression unless they are different in context. Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as those commonly understood by a person skilled in the art to which the disclosure pertains. Such terms as those defined in a generally used dictionary may be interpreted to have the same meanings as the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the disclosure. In some cases, even the term defined in the disclosure should not be interpreted to exclude embodiments of the disclosure.

Hereinafter, embodiments will be described based on hardware. However, the embodiments include a technology that uses both hardware and software and thus, may also include software.

The disclosure relates to an apparatus and a method for configuring an RLC function parameter to support a V2X service through a direct communication protocol between UEs in a wireless communication system. Specifically, the disclosure describes technology for satisfying a QoS level required for various V2X services based on a method of a UE for configuring an RLC parameter required for supporting high-speed data transmission and high reliability, which are needed for sidelink direct communication between V2X UEs in a wireless communication system.

Terms referring to a signal used in the following description, terms referring to a channel, terms referring to control information, terms referring to network entities, and terms referring to elements of a device are used only for convenience of description. Accordingly, the disclosure is not limited to those terms, and other terms having the same technical meanings may be used.

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

<FIG> illustrates a BS <NUM>, UE #<NUM><NUM>, and UE #<NUM><NUM> as some of the nodes using a radio channel in a wireless communication system. Although <FIG> illustrates only one BS, another BS that is the same as or similar to the BS <NUM> may be further included. Although <FIG> illustrates only two UEs, another UE that is the same as or similar to UE #<NUM><NUM> and UE #<NUM><NUM> may be further included.

The BS <NUM> is a network infrastructure element that provides radio access to the UEs <NUM> and <NUM>. The BS <NUM> has coverage defined in a predetermined geographical area based on the range within which a signal can be transmitted and received. The BS <NUM> may be referred to as an "access point (AP)", "eNodeB (eNB)", "<NUM>h-generation (<NUM>) node", "<NUM> nodeB (NB)", "wireless point", or "transmission/reception point (TRP)", or using another term having a technical meaning equivalent thereto.

Each of UE #<NUM><NUM> and UE #<NUM><NUM> is used by a user and communicates with the BS <NUM> through a radio channel. Depending on the circumstances, at least one of UE #<NUM><NUM> and UE #<NUM><NUM> may be operated without user involvement. That is, at least one of UEs #<NUM><NUM> and UE #<NUM><NUM> performs MTC and may not be carried by the user. Each of UE #<NUM><NUM> and UE #<NUM><NUM> may be referred to as a "user equipment", "mobile station", "subscriber station", "remote terminal", "wireless terminal", or "user device", or using another term having the same meaning, as well as "terminal".

The BS <NUM>, UE #<NUM><NUM>, and UE #<NUM><NUM> may transmit and receive a wireless signal in a subband of <NUM> gigahertz (GHz) and mmWave bands (for example, <NUM>, <NUM>, <NUM>, and <NUM>). In order to increase channel gain, the BS <NUM>, the UE #<NUM><NUM>, and the UE #<NUM><NUM> may perform beamforming, which may include transmission beamforming and reception beamforming. That is, the BS <NUM>, the UE #<NUM><NUM>, and the UE #<NUM><NUM> may assign 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 beam management procedure. After the serving beams <NUM>, <NUM>, <NUM>, and <NUM> are selected, communication may be performed through resources having a quasi-co-located (QCL) relationship with resources through which the serving beams <NUM>, <NUM>, <NUM>, and <NUM> are transmitted.

If the large-scale characteristics of a channel for transmitting symbols through a first antenna port can be inferred from a channel for transmitting symbols through a second antenna port, the first antenna port and the second antenna port may be evaluated to have a QCL relationship therebetween. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameters.

<FIG> illustrates the configuration of a BS in a wireless communication system according to an embodiment.

The configuration illustrated in <FIG> may be the configuration of the BS <NUM>. The term ". unit" or the ending of a word, such as ". er", may indicate a unit of processing at least one function or operation, and may be embodied by hardware, software, or a combination of hardware and software.

Referring to <FIG>, the BS includes a wireless communication unit <NUM>, a backhaul communication unit <NUM>, a storage unit <NUM>, and a controller <NUM>.

The wireless communication unit <NUM> performs functions for transmitting and receiving a signal through a radio channel. For example, the wireless communication unit <NUM> performs a function of conversion between a baseband signal and a bitstream according to the physical-layer standard of the system. In data transmission, the wireless communication unit <NUM> may encode and modulate a transmission bitstream to generate complex symbols. In data reception, the wireless communication unit <NUM> reconstructs a reception bitstream by demodulating and decoding a baseband signal.

In addition, the wireless communication unit <NUM> up-converts a baseband signal into a radio-frequency (RF) band signal which it transmits through an antenna, and down-converts an RF band signal received through an antenna into a baseband signal. To this end, the wireless communication unit <NUM> may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog convertor (DAC), and an analog-to-digital convertor (ADC), for example. The wireless communication unit <NUM> may include a plurality of transmission/reception paths and at least one antenna array including a plurality of antenna elements.

On the hardware side, the wireless communication unit <NUM> may include a digital unit and an analog unit. The analog unit may include a plurality of sub-units according to operating power, operating frequency, and the like. The digital unit may be implemented by at least one processor, such as a digital signal processor (DSP).

The wireless communication unit <NUM> transmits and receives a signal as described above. Accordingly, all or part of the wireless communication unit <NUM> may be referred to as a "transmitter", a "receiver", or a "transceiver". In the following description, transmission and reception performed through a radio channel may include the above-described processing by the wireless communication unit <NUM>.

The backhaul communication unit <NUM> provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit <NUM> converts a bitstream transmitted from the BS to another access node, another BS, a higher node, or a core network, into a physical signal, and converts a physical signal received from the node into a bitstream.

The storage unit <NUM> may store data such as a basic program for the operation of the BS, an application, and configuration information. The storage unit <NUM> may include at least one of a volatile memory and nonvolatile memory. The storage unit <NUM> provides stored data in response to a request from the controller <NUM>.

The controller <NUM> may control the overall operation of the BS. For example, the controller <NUM> transmits and receives a signal through the wireless communication unit <NUM> or the backhaul communication unit <NUM>. The controller <NUM> records and reads data in the storage unit <NUM>. The controller <NUM> may perform the functions of a protocol stack required for communication standards. According to another implementation, the protocol stack may be included in the wireless communication unit <NUM>. To this end, the controller <NUM> may include at least one processor.

The controller <NUM> may transmit RRC configuration information to the UEs <NUM> and <NUM>. The controller <NUM> may transmit sidelink configuration information to the UEs <NUM> and <NUM>. For example, the controller <NUM> may control the BS to perform operations according to embodiments described below.

<FIG> illustrates the configuration of a UE in a wireless communication system according to an embodiment.

The configuration illustrated in <FIG> may be the configuration of UE #<NUM><NUM> or UE #<NUM><NUM>. Referring to <FIG>, the UE includes a communication unit <NUM>, a storage unit <NUM>, and a controller <NUM>.

The communication unit <NUM> performs functions for transmitting and receiving a signal through a radio channel. For example, the communication unit <NUM> performs a function of conversion between a baseband signal and a bitstream according to a physical-layer standard of the system. In data transmission, the communication unit <NUM> encodes and modulates a transmission bitstream to generate complex symbols. In data reception, the communication unit <NUM> reconstructs a reception bitstream by demodulating and decoding a baseband signal. The communication unit <NUM> up-converts a baseband signal to an RF band signal, transmits the RF band signal through an antenna, and then down-converts the RF band signal received through the antenna to the baseband signal. The communication unit <NUM> may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC.

The communication unit <NUM> may include a plurality of transmission/reception paths. The communication unit <NUM> may include at least one antenna array including a plurality of antenna elements. On the hardware side, the communication unit <NUM> may include a digital circuit and an analog circuit, such as a radio-frequency integrated circuit (RFIC). The digital circuit and the analog circuit may be implemented as a single package. The communication unit <NUM> may include a plurality of RF chains and may perform beamforming.

The communication unit <NUM> may include different communication modules for processing signals in different frequency bands. The communication unit <NUM> may include a plurality of communication modules for supporting a plurality of different radio access technologies. For example, the different radio access technologies may include Bluetooth™ low energy (BLE), wireless fidelity (Wi-Fi), Wi-Fi gigabyte, and a cellular network, such as LTE. Different frequency bands may include a super-high-frequency (SHF) (for example, <NUM>, <NUM>, and <NUM>) band and an mm wave (for example, <NUM>) band.

The communication unit <NUM> transmits and receives a signal, and thus, may be referred to as a "transmitter", a "receiver", or a "transceiver". Transmission and reception performed through a wireless channel may indicate that the above-described processing is performed by the communication unit <NUM>.

The storage unit <NUM> stores data such as a basic program, an application, and configuration information for the operation of the UE. The storage unit <NUM> may include at least one of a volatile memory and nonvolatile memory. The storage unit <NUM> provides stored data in response to a request from the controller <NUM>.

The controller <NUM> controls the overall operation of the UE. For example, the controller <NUM> transmits and receives a signal through the communication unit <NUM>. The controller <NUM> records and reads data in the storage unit <NUM>. The controller <NUM> may perform the functions of a protocol stack required by the communication standard. To this end, the controller <NUM> may include at least one processor or microprocessor or may be a part of the processor. The part of the communication unit <NUM> or the controller <NUM> may be referred to as a communications processor (CP).

The controller <NUM> may perform a process of determining a data transmission requirement of a V2X application for performing sidelink direct communication between the UEs <NUM> and <NUM> and another UE, informing the BS <NUM> of required data transmission information, receiving an RLC function configuration parameter corresponding to required data transmission information from the BS, providing RLC function configuration parameter information to another UE, and processing data to be transmitted to another UE according to the RLC function configuration parameter information. For example, the controller <NUM> may control the UE to perform operations according to embodiments described below.

<FIG> illustrates the configuration of a communication unit in a wireless communication system according to an embodiment.

Referring to <FIG>, the wireless communication unit <NUM> or the communication unit <NUM> includes an encoding and modulation unit <NUM>, a digital beamforming unit <NUM>, a plurality of transmission paths <NUM>-<NUM> to <NUM>-N, and an analog beamforming unit <NUM>.

The encoding and modulation unit <NUM> performs channel encoding, for which at least one of a low-density parity check (LDPC) code, a convolution code, and a polar code may be used. The encoding and modulation unit <NUM> generates modulation symbols by performing constellation mapping.

The digital beamforming unit <NUM> performs beamforming on a digital signal (for example, modulation symbols). To this end, the digital beamforming unit <NUM> multiplies beamforming weights by modulation symbols. The beamforming weight values may be used for changing the size and phase of the signal and may be referred to as a "precoding matrix" or a "precoder". The digital beamforming unit <NUM> outputs digitally beamformed modulation symbols through the plurality of transmission paths <NUM>-<NUM> to <NUM>-N. According to a MIMO transmission scheme, the modulation symbols may be multiplexed, or the same modulation symbols may be provided to the plurality of transmission paths <NUM>-<NUM> to <NUM>-N.

The plurality of transmission paths <NUM>-<NUM> to <NUM>-N converts the digitally beamformed digital signals into analog signals. To this end, each of the plurality of transmission paths <NUM>-<NUM> to <NUM>-N may include an inverse fast Fourier transform (IFFT) calculator, a cyclic prefix (CP) inserter, a DAC, and an up-converter. The CP inserter is for an orthogonal frequency-division multiplexing (OFDM) scheme and may be omitted when another physical layer scheme (for example, a filter bank multi-carrier (FBMC) scheme) is applied. That is, the plurality of transmission paths <NUM>-<NUM> to <NUM>-N provides independent signal-processing processes for a plurality of streams generated through the digital beamforming. However, depending on the implementation, some of the elements of the plurality of transmission paths <NUM>-<NUM> to <NUM>-N may be used in common.

The analog beamforming unit <NUM> performs beamforming on an analog signal. To this end, the digital beamforming unit <NUM> multiplies beamforming weights by analog signals. The beamforming weights are used to change the size and phase of the signal. More specifically, the analog beamforming unit <NUM> may be configured as illustrated in <FIG> or <FIG> according to the connection structure between the plurality of transmission paths <NUM>-<NUM> to <NUM>-N and the antennas.

<FIG> illustrates the configuration of a communication unit in a wireless communication system according to an embodiment. Referring to <FIG>, signals input into the analog beamforming unit <NUM> may be transmitted through the antennas via phase/size conversion and amplification operation. The signals in respective paths are transmitted through different antenna arrays (or sets). In processing of signals input through a first path, the signals are converted into signal sequences having the same or different phase/size by phase/size conversion units <NUM>-<NUM>-<NUM> to <NUM>-<NUM>-M, amplified by amplifiers <NUM>-<NUM>-<NUM> to <NUM>-<NUM>-M, and transmitted through antennas.

Referring to <FIG>, the signals input into the analog beamforming unit <NUM> are transmitted through the antennas via phase/size conversion and amplification operation. The signals in respective paths are transmitted through the same antenna array. In the processing of signals input through a first path, the signals are converted into signal sequences having the same or different phases/sizes by the phase/size conversion units <NUM>-<NUM>-<NUM> to <NUM>-<NUM>-M, and are amplified by the amplifiers <NUM>-<NUM>-<NUM> to <NUM>-<NUM>-M. The amplified signals to be transmitted through one antenna are summed by summing units <NUM>-<NUM> to <NUM>-M based on antenna elements and are then transmitted through 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, some transmission paths may use independent antenna arrays and the remaining transmission paths may share one antenna array. Also, a structure that may adaptively vary depending on the situation may be used by applying a switchable structure between transmission paths and antenna arrays.

A V2X service may be divided into a basic safety service and an advanced service. The basic safety service may correspond to detailed services such as a vehicle notification ((cooperative awareness messages (CAM) or basic safety message (BSM)) service, a left-turn notification service, a forward collision warning service, an approaching emergency vehicle notification service, a forward obstacle warning service, and an intersection signal information service, and may transmit and receive V2X information through a broadcast, unicast, or groupcast transmission scheme.

The advanced service has more stringent QoS requirements compared to the basic safety service, and needs a scheme of transmitting and receiving V2X information through unicast and broadcast transmission schemes, rather than the broadcast transmission scheme, in order to transmit and receive V2X information within a specific vehicle group or between two vehicles. The advanced service may correspond to detailed services such as a platooning service, an autonomous driving service, a remote driving service, and an extended sensor-based V2X service.

For the V2X service, the UE may perform the V2X service in an ng-RAN (gNB) connected to a <NUM> core network or an E-UTRAN (ng-eNB) connected to a <NUM> core network through the ng-RAN or the E-UTRAN. When the BS (ng-RAN or ng-eNB) is connected to an evolved packet core (EPC) network, the V2X service may be performed through the BS. When the BS is connected to an evolved packet core (EPC) network, the V2X service may be performed through the BS. A V2X wireless interface communication scheme that can be used for direct communication between UEs may be at least one of unicast, groupcast, and broadcast schemes, and a method of managing and configuring a wireless communication parameter suitable for QoS requirements of the V2X service should be provided when V2X transmission/reception is performed in each of the communication schemes.

A system for performing direct communication between UEs based on LTE wireless communication is defined such that a transmission UE selects and operates parameters that it requires for transmission. In the case of LTE wireless communication, a V2X service message for basic safety is transmitted between UEs through a direct communication scheme. QoS requirements of the basic safety V2X service are not strict, and even if there is a variety of basic safety services, the variety of QoS requirements between services is low, and differences between services are minimal. Accordingly, even in a mode in which the BS schedules radio resources to be used for direct communication between UEs based on LTE wireless communication, the BS simply schedules radio resources without any need to acquire detailed QoS requirement information of the V2X service, and the UE manages and configures parameters.

Advanced V2X services have various QoS requirements, and the QoS level of each V2X service may greatly vary. A specific advanced V2X service can be executed only when radio resources and radio parameters for direct communication are configured so as to satisfy the strict QoS requirements of the service. Accordingly, a system based on direct communication between UEs for supporting the advanced V2X service should provide a better method of guaranteeing QoS than the conventional system.

<FIG> illustrates direct communication between UEs through a sidelink RAT according to a first embodiment. In <FIG>, UEs in the gNB coverage perform direct communication. Resource allocation configuration parameter information of a sidelink radio bearer to be used for transmitting and receiving a V2X packet based on unicast, broadcast, or groupcast between UEs may be transmitted to the UEs <NUM> and <NUM> through a system information message or an RRC-dedicated message of the gNB <NUM>, or may be configured in advance in the UEs <NUM> and <NUM>. The UEs <NUM> and <NUM> performing direct communication by NR V2X SL may transmit data rate information required by the V2X service packet to the gNB <NUM> and acquire sidelink resource allocation and/or RLC function configuration parameter information from the gNB <NUM>. The sidelink RLC function configuration parameter information may be transferred to another UE.

<FIG> illustrates direct communication between UEs through a sidelink RAT according to a second embodiment. In <FIG>, the UEs <NUM> and <NUM> in the ng-eNB coverage perform direct communication. Resource allocation configuration parameter information of a sidelink radio bearer to be used for transmitting and receiving a V2X packet based on unicast, broadcast, or groupcast between UEs may be transmitted to the UEs <NUM> and <NUM> through a system information message or an RRC dedicated message of the ng-eNB <NUM> or configured in advance in the UEs <NUM> and <NUM>. The UEs <NUM> and <NUM> performing direct communication by NR V2X SL may transmit data rate information required by the V2X service packet to the ng-eNB <NUM> and acquire sidelink resource allocation and/or RLC function configuration parameter information from the ng-eNB <NUM>. The sidelink RLC function configuration parameter information may be transferred to another UE.

<FIG> illustrates direct communication between UEs through a sidelink RAT according to a third embodiment. In <FIG>, the UE <NUM> in the gNB coverage and the UE <NUM> in the eNB coverage perform direct communication. Resource allocation configuration parameter information of a sidelink radio bearer to be used for transmitting and receiving a V2X packet based on unicast, broadcast, or groupcast between UEs may be transmitted to the UEs <NUM> and <NUM> through a system information message or an RRC dedicated message of the gNB <NUM>, or may be configured in advance in the UEs <NUM> and <NUM>. The UEs <NUM> and <NUM> performing direct communication by NR V2X SL may transmit data rate information required by the V2X service packet to the gNB <NUM> and acquire sidelink resource allocation and/or RLC function configuration parameter information from the gNB <NUM>. The sidelink RLC function configuration parameter information may be transferred to another UE.

<FIG> illustrates direct communication between UEs through a sidelink RAT according to a fourth embodiment. In <FIG>, the UEs <NUM> and <NUM> in the eNB coverage perform direct communication. Resource allocation configuration parameter information of a sidelink radio bearer to be used for transmitting and receiving a V2X packet based on unicast, broadcast, or groupcast between UEs may be transmitted to the UEs <NUM> and <NUM> through a system information message or an RRC dedicated message of the eNB <NUM>, or may be configured in advance in the UEs <NUM> and <NUM>. The UEs <NUM> and <NUM> performing direct communication by NR V2X SL may transmit data rate information required by the V2X service packet to the eNB <NUM> and acquire sidelink resource allocation and/or RLC function configuration parameter information from the eNB <NUM>. The sidelink RLC function configuration parameter information may be transferred to another UE.

The sidelink RLC function configuration parameter for performing direct communication between UEs may be used to perform PC5 RRC signaling transmission/reception in the unicast manner, transmit/receive a V2X message in the unicast manner, transmit/receive a V2X message in the broadcast manner, and transmit/receive a V2X message in the groupcast manner.

Sidelink direct communication may be used to perform PC5 RRC signaling transmission/reception used for configuring and managing a unicast connection between UEs and to transmit/receive V2X data that can be exchanged between UEs in the unicast manner, groupcast manner, and broadcast manner. Configuration information required for performing PC5 RRC signaling transmission/reception may include a function configuration parameter for each layer, such as packet data convergence protocol (PDCP), radio link control (RLC), medium access control (MAC), or physical (PHY). Configuration information required for transmitting/receiving V2X data may include a function configuration parameter for each layer, such as PDCP, RLC, MAC, or PHY. The disclosure describes a method of operating the sequence number (SN) size and an ARQ configuration parameter, among RLC layer functions applied to PC5 RRC signaling and V2X data. The RLC layer function configuration parameter may be configured according to at least one of a determination method by a UE implementation, a preconfigured method, a method configured by the BS (RRC-dedicated signaling or V2X SIB signaling), and a method configured by the UE (PC5 RRC-dedicated signaling, PC5 MIB, or PC5 SIB).

<FIG> illustrates a signal procedure for operating an RLC function configuration parameter to be applied to sidelink RRC according to an embodiment. This embodiment is however not covered by the claims. <FIG> illustrates a method by which the BS configures an RLC function configuration parameter required for configuring a PC5 RRC connection between UEs and informs the UE of the same. The BS may indicate the configuration of the RLC function configuration parameter required for configuring the PC5 RRC connection and/or update the parameter to a new value.

Referring to <FIG>, UE #<NUM><NUM> may determine that a PC5 RRC connection for a sidelink unicast connection with UE #<NUM><NUM> is needed and start a PC5 RRC configuration procedure in step <NUM>. UE #<NUM><NUM> may transmit a SidelinkUEInformation message to inform a BS <NUM> of the PC5 RRC connection configuration in step <NUM>. The BS <NUM> may configure information received from UE #<NUM><NUM>, that is, sidelink radio resources and configuration information required for PC5 RRC connection configuration, based on the PC5 RRC connection configuration notification in step <NUM>. The BS <NUM> may transmit an RRCReconfiguration message or an RRCConnectionReconfiguration message including the information configured in step <NUM> to UE #<NUM><NUM> in step <NUM>. The message in step <NUM> may include RLC function configuration parameter information required for the PC5 RRC connection. An embodiment of the RLC function configuration parameter information may include Table <NUM>, as shown below.

In step <NUM>, UE #<NUM><NUM> may determine RLC function configuration parameter information for PC5 RRC connection with UE #<NUM><NUM> based on the RLC function configuration parameter information received in step <NUM>. UE #<NUM><NUM> may inform UE #<NUM><NUM> of the RLC function configuration parameter information. UE #<NUM><NUM> and UE #<NUM> may perform a PC5 RRC connection configuration procedure based on the RLC function configuration parameter information in step <NUM>. A description of the detailed procedure of the PC5 RRC connection configuration is omitted. When the RLC function configuration parameter information is not received in step <NUM>, UE #<NUM><NUM> and UE #<NUM><NUM> may perform the PC5 RRC connection configuration procedure based on RLC function configuration parameter information set in a default configuration. An embodiment of the default configuration is as shown in Table <NUM>, as follows.

UE # <NUM> or UE #<NUM><NUM> may receive an RRCReconfiguration message, an RRCConnectionReconfiguration message, or a V2X SIB including RLC function configuration parameter information for PC5 RRC while transmitting and receiving PC5 RRC connection configuration signaling according to the default configuration or a preset configuration. This procedure may correspond to step <NUM>, and the embodiment of the RLC function configuration parameter information may include Table <NUM>, as shown below. UE #<NUM><NUM> and UE #<NUM><NUM> may transmit and receive PC5 RRC connection configuration signaling according to a new RLC function configuration parameter for PC5 RRC. UE #<NUM><NUM> and UE #<NUM><NUM>, acquiring the new RLC function configuration parameter for PC5 RRC, may inform the counterpart UE (UE #<NUM> or UE #<NUM>) of the new RLC function configuration parameter. PC5 RRC signaling including the new RLC function configuration parameter for PC5 RRC may be transmitted and received through the application of a pre-used RLC function configuration parameter (or default configuration). The new RLC function configuration parameter for PC5 RRC may be applied after PC5 RRC complete signaling corresponding to the PC5 RRC signaling. For example, the PC5 RRC signaling may include AS configuration and AS configuration complete. This procedure may correspond to step <NUM>.

<FIG> illustrates a signal procedure for operating an RLC function configuration parameter to be applied to sidelink RRC according to an embodiment. This embodiment is however not covered by the claims.

<FIG> illustrates a method by which the UE configures an RLC function configuration parameter required for configuring a PC5 RRC connection and informing the counterpart UE of the parameter. The UE may indicate the configuration of the RLC function configuration parameter required for configuring the PC5 RRC connection and/or update the parameter to a new value.

Referring to <FIG>, UE #<NUM><NUM> may determine that the PC5 RRC connection for a sidelink unicast connection with UE #<NUM><NUM> is needed and start a PC5 RRC configuration procedure in step <NUM>. UE #<NUM><NUM> may transmit a SidelinkUEInformation message to inform a BS <NUM> of the PC5 RRC connection configuration in step <NUM>. The BS <NUM> may configure information received from UE #<NUM><NUM>, that is, sidelink radio resources and configuration information required for PC5 RRC connection configuration, based on the PC5 RRC connection configuration notification in step <NUM>. The BS <NUM> may transmit an RRCReconfiguration message and an RRCConnectionReconfiguration message including the information configured in step <NUM> to UE #<NUM><NUM> in step <NUM>. UE #<NUM><NUM> may determine RLC function configuration parameter information for PC5 RRC with UE #<NUM><NUM> in step <NUM> as well as the sidelink radio resources and configuration information received in step <NUM>. UE #<NUM><NUM> may inform UE #<NUM><NUM> of the RLC function configuration parameter information.

An embodiment of the RLC function configuration parameter information may include Table <NUM>, as shown below. UE #<NUM><NUM> and UE #<NUM> may perform a PC5 RRC connection configuration procedure based on the RLC function configuration parameter information for PC5 RRC in step <NUM>. A description of the detailed procedure of the PC5 RRC connection configuration is omitted.

In step <NUM>, UE #<NUM><NUM> may determine to use the default configuration of Table <NUM> as the RLC function configuration parameter for PC5 RRC with UE #<NUM><NUM>. At this time, UE #<NUM><NUM> and UE #<NUM><NUM> may perform the PC5 RRC connection configuration procedure based on the RLC function configuration parameter information set in the default configuration in Table <NUM>.

Alternatively, UE #<NUM> and UE #<NUM> may determine a change in the RLC function configuration parameter while transmitting and receiving PC5 RRC connection configuration signaling according to the default configuration or a preset configuration, which may correspond to step <NUM>. UE #<NUM> and UE #<NUM> may transfer PC5 RRC signaling including new RLC function configuration parameter information to the counterpart UE, which also includes Table <NUM>. PC5 RRC signaling including the new RLC function configuration parameter for PC5 RRC may be transmitted and received through the application of a pre-used RLC function configuration parameter (or default configuration). The new RLC function configuration parameter for PC5 RRC may be applied after PC5 RRC complete signaling corresponding to the PC5 RRC signaling. For example, the PC5 RRC signaling may include AS configuration and AS configuration complete, which may correspond to step <NUM>.

The RLC function configuration parameter that can be applied to transmission/reception of PC5 signaling (for example, signaling SLRB) may include at least one piece of information in Table <NUM>, Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>, as shown below.

The RLC function configuration parameter that can be applied to transmission/reception of V2X data (for example, data SLRB) may include at least on piece of information in Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>, as shown below.

The RLC function configuration parameter according to Table <NUM> above may be applied to each sidelink unicast-based SLRB, each sidelink broadcast-based SLRB, or each sidelink groupcast-based SLRB. The RLC function configuration parameter may be configured by at least one of a method following a UE implementation, a preset method, a method configured by the BS, and a method configured by the UE.

<FIG> illustrates a signal procedure for operating an RLC function configuration parameter to be applied to sidelink data according to an embodiment.

Referring to <FIG>, UE #<NUM><NUM> may determine sidelink unicast-based V2X data transmission with UE #<NUM><NUM> in step <NUM>. UE #<NUM><NUM> transmits a SidelinkUEInformation message to inform a BS <NUM> of the sidelink unicast-based V2X data transmission in step <NUM>. The information provided through the SidelinkUEInformation message includes a required data rate.

The information provided through the SidelinkUEInformation message includes at least one of the parameters in Table <NUM> and Table <NUM>, as shown below, at least one piece of information on unicast, groupcast, and broadcast (this is, a cast type, mandatory) and at least one of a destination identifier (mandatory), a ProSeQos indicator, PQI, a QoS flow identifier, QFI (mandatory), required reliability information, and required latency information. The BS <NUM> configures information received from UE #<NUM><NUM>, that is, sidelink radio resources and configuration information required for sidelink unicast-based data transmission/reception, based on a sidelink unicast-based V2X data transmission notification. The BS <NUM> configures configures the RLC function configuration parameter with reference to at least one of a cast type provided by the UE, the destination identifier, the PQI, the QFI, the required reliability information, the required latency information, and the required data rate (mandatory). Examples of the RLC function configuration parameter may include at least one of the parameters in Table <NUM>, as shown above and Table <NUM>, as shown below.

The BS <NUM> transmits an RRCReconfiguration message or an RRCConnectionReconfiguration message including the information configured in step <NUM> to UE #<NUM><NUM> in step <NUM>. The message in step <NUM> includes RLC function configuration parameter information required for sidelink unicast-based data transmission/reception. In step <NUM>, UE #<NUM><NUM> may determine RLC function configuration parameter information for sidelink unicast-based data transmission/reception with UE #<NUM><NUM> based on the RLC function configuration parameter information received in step <NUM>. The RLC function configuration parameter information may include Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>, as shown below. UE #<NUM><NUM> and UE #<NUM><NUM> perform the parameter configuration for sidelink unicast data transmission including the RLC function configuration parameter for sidelink unicast-based data transmission/reception in step <NUM>.

The information through which the UE informs the BS of data rate information required for a V2X application, that is, V2X data, to be transmitted/received in sidelink may include at least one piece of information shown in Table <NUM>, as follows.

In Table <NUM>, data rate information may be indicated by a data rate index or a data rate value.

The data rate value may be the value of a data rate required for each V2X application.

The data rate index may be the index of a data rate required for each V2X application. All available data rates are divided into data rates in predetermined sections in consideration of V2X applications, and an index is designated to each section. The data rate index may be configured as in Table <NUM>, as follows.

The data rate information may be referenced to determine the SN size in Table <NUM> and/or an ARQ parameter (for example, PollPDU or PollByte) among the RLC function configuration parameters.

The RLC function configuration parameter may include at least one piece of information in Table <NUM>, as shown below.

RX-AM-RLC may correspond to an RLC function configuration parameter to be used by a reception UE in an RLC AM mode, TX-AM-RLC may correspond to a transmit RLC function configuration parameter to be used by a transmission UE in the RLC AM (acknowledged mode), RX-UM-RLC may correspond to a receive RLC function configuration parameter to be used by the reception UE in an RLC UM (unacknowledged mode), and TX-UM-RLC may correspond to an RLC function configuration parameter to be used by the transmission UE in the RLC UM mode.

Alternatively, the configured RLC function configuration parameter may be changed, which may be determined by the BS or the UE (UE #<NUM> or UE #<NUM>). The RLC function configuration parameter required to be changed may be transferred to the counterpart UE (UE #<NUM> or UE #<NUM>).

The BS may manage mapping information between data rate information and information required for configuring the RLC function configuration parameter, such as the SN size in the RLC AM mode, the SN size in the RLC UM mode, and ARQ parameter configuration (for example, PollByte or PollPDU) based on data rate information required by the UE. The mapping information may be provided by a V2X server to the BS.

<FIG> illustrates when the UE is in an RRC _Connected state, and an embodiment in which the UE is in an RRC_Idle state or an RRC Inactive state and/or the UE is out of a coverage area may include at least one of the following cases (this embodiment is however not covered by the claims).

The RRC_Inactive UE or the RRC_Idle UE may receive a V2X SIB message including Table <NUM> and Table <NUM> from the BS and acquire RLC function configuration parameter information. The RRC_Inactive UE or the RRC_Idle UE may acquire preconfigured RLC function configuration parameter information of Table <NUM> and Table <NUM>. The out-of-coverage UE may acquire preconfigured RLC function configuration parameter information of Table <NUM> and Table <NUM>.

When the dataRateIndex is included in Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>, an RLC function configuration parameter of the dataRateIndex corresponding to a required data rate may be applied.

When the dataRate is included in Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>, an RLC function configuration parameter of the dataRate corresponding to a required data rate may be applied.

When the thresDataRate is included in Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>, the RLC function configuration parameter may be applied only when a required data rate is less than thresDataRate. Alternatively, when thresDataRate is included in Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>, the RLC function configuration parameter may be applied only when a required data rate is greater than the thresDataRate.

The RLC function configuration parameter may be configured as a set of parameters as shown in Table <NUM> below, and parameters included in each set may include at least one of the parameters in Table <NUM>, Table <NUM>, Table <NUM>, Table <NUM> and Table <NUM>.

When the BS performs a configuration in the UE, an index of an RLC function configuration parameter set may be indicated. When the UE informs the counterpart UE of the RLC function configuration parameter that is preconfigured or is selected by itself, an index of an RLC function configuration parameter set may be indicated. The RLC function configuration parameter set of Table <NUM> may be indicated and/or configured to be linked with data rate information. For example, an RLC function configuration parameter set corresponding to data rate A may be indicated and/or configured. An RLC function configuration parameter set corresponding to data rate index B may be indicated and/or configured. For example, an RLC function configuration parameter set corresponding to data rate C may be indicated and/or configured.

When RLC function configuration parameter information is configured according to a UE implementation, the UE may manage the information in Table <NUM> to Table <NUM> and configure an RLC function configuration parameter, such as the SN size and/or an ARQ parameter, based on data rate information required by V2X data.

When an RLC function configuration parameter for transmitting and receiving sidelink broadcast-based V2X data is configured and/or an RLC function configuration for transmitting and receiving sidelink groupcast-based V2X data is configured, the configuration method through RRC signaling of the BS, the preconfigured method, the configuration method through PC5 signaling of the UE, and the configuration method by the UE implementation may be applied as illustrated in <FIG>. Table <NUM> to Table <NUM> may also be applied.

<FIG> illustrates a method of the UE for measuring and reporting congestion of sidelink resources according to an embodiment. This embodiment is however not covered by the claims. In order to determine the state of use of sidelink resources (for example, a sidelink resource congestion state), the BS may make a request for measuring and reporting congestion of a sidelink resource pool to the UE. The UE may be in the RRC_Connected state. The BS may instruct the UE to configure the measurement and report on the congestion through an RRCReconfiguration message or an RRCConnectionReconfiguration message. The configuration of the measurement and report on the congestion may include at least one of an event-based report and a periodic report, as well as at least one piece of sidelink resource pool information to be measured and reported.

When the BS supports configuration and allocation of LTE sidelink resources and/or configuration and allocation of NR sidelink resources, the BS may instruct the UE to measure and report congestion of the LTE sidelink resource pool and/or the NR sidelink resource pool. The BS may instruct the UE to measure and report the congestion of a sidelink resource pool of a secondary RAT. When the UE is instructed to measure and report the congestion of the sidelink resource pool of the secondary RAT, the UE may measure this congestion through a congestion measurement scheme of the secondary RAT and report the congestion according to a configured report scheme. Since an LTE-based channel busy ratio (CBR) measurement and report scheme and an NR-based CBR measurement and report scheme may be defined differently, the UE needs to know indication information indicating whether to follow the LTE scheme or the NR scheme.

Referring to <FIG>, the UE may receive configuration of SL measurement and a report on congestion of a sidelink resource pool from the BS in step <NUM>. The UE may determine whether the configuration includes the configuration of measurement and report on congestion of the LTE sidelink resource pool in step <NUM>. When the configuration includes the configuration of measurement and report on congestion of the LTE sidelink resource pool based on the determination in step <NUM>, the UE may measure congestion of the LTE sidelink resource pool and report the congestion according to the report configuration in step <NUM>. A procedure of measuring and reporting congestion of the LTE sidelink resource pool may correspond to a CBR measurement and report procedure defined in LTE-V2X.

The UE may determine whether the configuration in step <NUM> includes configuration of measurement and report on congestion for the NR sidelink resource pool in step <NUM>. When the configuration is found to include the configuration of measurement and report on congestion for the NR sidelink resource pool based on the determination in step <NUM>, the UE may measure the congestion for the NR sidelink resource pool and report the congestion according to the report configuration in step <NUM>. A procedure of measuring and reporting congestion of the NR sidelink resource pool may correspond to a CBR measurement and report procedure defined in NR-V2X.

The CBR measurement and report procedure defined in NR-V2X may include an operation procedure for determining an NR sidelink frame structure, a resource structure, a reference signal (RS), and congestion of a resource pool, and may be different from the procedure defined in LTE-V2X. When the configuration does not include the configuration of measurement and report on congestion for the LTE sidelink resource pool based on the determination in step <NUM>, the UE may proceed to step <NUM>. When the configuration is found not to include the configuration of measurement and report on congestion for the NR sidelink resource pool based on the determination in step <NUM>, the UE may end the procedure.

<FIG> illustrates a method of the UE for measuring and reporting congestion of sidelink resources according to an embodiment. This embodiment is however not covered by the claims.

Referring to <FIG>, the UE may receive configuration of SL measurement and report on congestion for a sidelink resource pool from the BS in step <NUM>. The UE may determine whether the configuration includes the configuration of measurement and report on congestion of the LTE sidelink resource pool in step <NUM>. When the configuration includes the configuration of measurement and report on congestion of the LTE sidelink resource pool based on the determination in step <NUM>, the UE may measure congestion of the LTE sidelink resource pool and report the congestion according to the report configuration in step <NUM>. The procedure of measuring and reporting congestion of the LTE sidelink resource pool may correspond to a CBR measurement and report procedure defined in LTE-V2X.

The UE may determine whether the configuration in step <NUM> includes the configuration of measurement and report on congestion for the NR sidelink resource pool in step <NUM>. When the configuration includes the configuration of measurement and the report on congestion for the NR sidelink resource pool based on the determination in step <NUM>, the UE may measure the congestion for the NR sidelink resource pool and report the congestion according to the report configuration in step <NUM>. The procedure of measuring and reporting congestion of the NR sidelink resource pool may correspond to a CBR measurement and report procedure defined in NR-V2X, which may include an operation procedure for determining an NR sidelink frame structure, a resource structure, a reference signal (RS), and congestion of a resource pool, and may be different from the procedure defined in LTE-V2X.

The information indicating the configuration of measurement and report on congestion for the LTE resource pool and the NR resource pool that the BS transmits to the UE in step <NUM> and step <NUM> may include at least one of the parameters in Table <NUM>, Table <NUM> and Table <NUM>, as shown below.

The UE may determine LTE configuration or NR configuration according to (<NUM>), (<NUM>), or (<NUM>), and may perform a CBR measurement and report based on LTE for the corresponding sidelink resource pool or perform a CBR measurement and report based on NR for the corresponding sidelink resource pool. Table <NUM> appears as follows.

As shown in Table <NUM>, configuration for the LTE sidelink resource pool and the NR sidelink resource pool to which the CBR measurement and report are applied may be included. Table <NUM> appears as follows.

As shown in Table <NUM>, RAT-type information to distinguish the LTE sidelink resource pool and the NR sidelink resource pool to which the CBR measurement and report are applied may be included. Table <NUM> appears as follows.

As shown in Table <NUM>, the CBR measurement report configuration information may include a separate CBR measurement and report configuration IE for each of LTE and NR.

<FIG> illustrates a signal procedure for configuring a sidelink resource allocation mode according to an embodiment.

This embodiment is however not covered by the claims.

A SidelinkUEInformation message and/or a UEAssistanceInformation message, transmitted when the UE informs the BS of sidelink information, may include at least one of sidelink resource allocation modes in which the UE is interested (BS scheduling mode <NUM> and UE scheduling mode <NUM>) and sidelink RAT information in which the UE is interested (LTE RAT, NR RAT, LTE & NR RATs).

Table <NUM>, as shown below, illustrates a SidelinkUEInformation message including sidelink resource allocation mode information and sidelink RAT information in which the UE is interested. The sidelink resource allocation mode information and/or the sidelink RAT information in which the UE is interested may also be included in a UEAssistanceInformation message.

The BS receiving the sidelink resource allocation mode information and/or the sidelink RAT information in which the UE is interested may indicate sidelink resource allocation and configuration to the UE through an RRCReconfiguration message or an RRCConnectionReconfiguration message with reference to information of interest to the UE.

Table <NUM> shows configuration information of the BS including at least one of sidelink resource allocation mode information indicated to the UE (mode <NUM>, mode <NUM>, or mode <NUM> & mode <NUM>), a destination ID list (unicast, groupcast, and broadcast destination IDs), a cast type indicator that may be included when it is difficult to identify a cast type through only a destination ID, an SLRB ID list (unicast, groupcast, and broadcast SLRB IDs), and an RAT type (LTE RAT, NR RAT, and LTE & NR RAT). Table <NUM> appears as follows.

Referring to <FIG>, the UE#<NUM><NUM> may determine whether a packet is generated in a V2X application, and may determine at least one of a cast type, a RAT type, and a sidelink resource allocation mode corresponding to the packet of the V2X application in step <NUM>. The cast type may correspond to unicast, groupcast, or broadcast. The RAT type may correspond to at least one of LTE and NR. The sidelink resource allocation mode may correspond to at least one of mode <NUM> and mode <NUM>.

The UE#<NUM><NUM> may inform the BS <NUM> of at least one of the cast type, the RAT type, and the sidelink resource allocation mode in which the UE is interested, as shown above in Table <NUM>, in step <NUM>. The message that the UE#<NUM><NUM> transmits to the BS <NUM> in step <NUM> may include at least one of a SidelinkUEInformation message or a UEAssistanceInformation message. The BS <NUM> may configure sidelink resource allocation and configuration information of the UE based on the information in which the UE is interested in step <NUM>.

The BS <NUM> may transmit the sidelink resource allocation and configuration information to the UE as shown in Table <NUM>, in step <NUM>. The message that the BS <NUM> transmits to the UE#<NUM><NUM> in step <NUM> may include at least one of an RRCReconfiguration message or an RRCConnectionReconfiguration message. The UE#<NUM><NUM> may perform a V2X packet transmission/reception procedure according to the received configuration information in step <NUM>.

A method of operating SLRB configuration based on PQL, QFI, and QoS requirements of the V2X application will now be described with reference to <FIG>. When PQIs, QFIs, and QoS requirements are the same or tolerant for V2X packets generated in one or more V2X applications, V2X application packet transmission/reception may be performed in the same SLRB. When PQIs, QFIs, and QoS requirements are different for V2X packets generated in one or more V2X applications, an SLRB corresponding to each PQI or QFI may be configured separately, and V2X application packet transmission/reception may be performed.

<FIG> illustrates a signal procedure for operating a sidelink bearer according to an embodiment. <FIG> illustrates the signal flow for configuring a new PC5 RRC unicast connection between UEs.

Referring to <FIG>, UE #<NUM><NUM> may determine the generation of a V2X packet corresponding to a V2X application and determine the cast type of the V2X packet in step <NUM>. When the cast type of the V2X packet is unicast, UE #<NUM><NUM> may identify whether a preset sidelink PC5 RRC configuration can be used in step <NUM>. When it is determined that a new sidelink PC5 RRC configuration is needed for the V2X packet in step <NUM>, UE #<NUM><NUM> may perform a PC5 RRC connection configuration and SLRB configuration procedure with UE #<NUM><NUM> in step <NUM>. UE #<NUM><NUM> may determine to transmit the V2X packet to the configured SLRB in step <NUM> and may transmit the V2X packet to UE #<NUM><NUM> through the configured SLRB in step <NUM>.

<FIG> illustrates a signal procedure for operating a sidelink bearer, i.e., the signal flow for transmitting and receiving a V2X packet through preset PC5 RRC unicast connection configuration information when a V2X packet for the same V2X application is generated between UEs, according to an embodiment.

Referring to <FIG>, UE #<NUM><NUM> and UE #<NUM><NUM> may have a PC5 RRC configuration and an SLRB configuration in step <NUM>. UE #<NUM><NUM> may determine the generation of a V2X packet corresponding to a V2X application and determine the cast type of the V2X packet in step <NUM>. When the cast type of the V2X packet is unicast, UE #<NUM><NUM> may determine whether the V2X packet belongs to SLRB of preset sidelink PC5 RRC in step <NUM>. When it is determined that the V2X packet can be transmitted through the preset SLRB in step <NUM>, UE #<NUM><NUM> may transmit the V2X packet to UE #<NUM><NUM> through the configured SLRB in step <NUM>.

<FIG> illustrates a signal procedure for operating a sidelink bearer, i.e., illustrates the signal flow for configuring a new PC5 unicast-based SLRB when a V2X packet for a new V2X application is generated between UEs, according to an embodiment.

Referring to <FIG>, UE #<NUM><NUM> and UE #<NUM><NUM> may have a PC5 RRC configuration and an SLRB configuration in step <NUM>. UE #<NUM><NUM> may determine the generation of a V2X packet corresponding to a V2X application and determine the cast type of the V2X packet in step <NUM>. When the cast type of the V2X packet is unicast, UE #<NUM><NUM> may determine whether the V2X packet belongs to SLRB of preset sidelink PC5 RRC in step <NUM>. When it is determined that the V2X packet cannot be transmitted through the preset SLRB in step <NUM>, UE #<NUM><NUM> may determine the necessity for a new SLRB configuration for transmitting the V2X packet. UE #<NUM><NUM> and UE #<NUM><NUM> may perform a sidelink PC5 RRC configuration procedure for the new SLRB configuration in step <NUM>. UE #<NUM><NUM> may transmit the V2X packet to UE #<NUM><NUM> through the configuration SLRB in step <NUM>.

Although <FIG>, <FIG>, and <FIG> illustrate only the signal flow between two UEs for performing the PC5 RRC connection configuration procedure and the SLRB configuration procedure using the PC5 RRC connection, the signal flow with the BS may be defined when the PC5 RRC connection configuration and SLRB configuration information is received from the BS.

<FIG> illustrates a method of the UE for processing a source identifier update for sidelink according to an embodiment. This embodiment is however not covered by the claims.

For example, on the side of peer UEs for performing sidelink unicast, a destination identification (DST ID) and a source identification (SRC ID) may be the same.

A sidelink-based V2X system should be able to change the SRC ID in order to prevent a problem of tracking a source UE. In the case of sidelink unicast, since the SRC ID of the UE may correspond to the DST ID of the peer UE, there may be a problem of changing the DST ID. Since the change in the SRC ID and the change in the DST ID may be interpreted as an indication of a new PC5 RRC connection, two UEs connected through unicast should be able to distinguish when a change in the SRC ID and the DST ID is needed from when a new PC5 RRC connection or a new PC5 SLRB configuration is needed. When the SRC ID and the DST ID are changed, the conventional PC5 RRC connection may be maintained. When the SRC ID and the DST ID are changed, the conventional PC5 SLRB configuration may be maintained.

The UE having the change in the SRC ID may provide notification of the change in the SRC ID from an upper layer of the UE to an RRC layer, and may inform the counterpart UE that the change in the DST ID is needed. The UE requiring the new PC5 RRC connection may provide notification of the necessity for the new PC5 RRC connection from an upper layer of the UE to an RRC layer. The UE may inform the counterpart UE that the new PC5 RRC connection is needed. Alternatively, the UE having the new PC5 SLRB configuration may provide notification of the necessity for the new PC5 SLRB configuration from an upper layer of the UE to an RRC layer. The UE may inform the counterpart UE that the new PC5 configuration is needed. UEs having the sidelink unicast connection may manage SLRB ID, SRC ID, and DST ID mapping information. UEs having the sidelink unicast connection may manage an SLRB ID list mapped to PC5 RRC. UEs having the sidelink unicast connection may manage SRC ID and DST ID information mapped to PC5 RRC.

Referring to <FIG>, the UE may determine whether a new PC5 RRC connection configuration is indicated in step <NUM> while a PC5 RRC connection is maintained in step <NUM>. When the new PC5 RRC connection configuration is indicated according to the determination in step <NUM>, the UE may perform a new PC5 RRC connection configuration procedure in step <NUM>. When a change in an SRC ID (source ID) is indicated according to the determination in step <NUM>, the UE may perform an SRC ID change procedure that is being used for the conventional PC5 RRC connection in step <NUM>. Step <NUM> and step <NUM> may pertain to information indicated from an upper layer of one UE to an RRC layer and may be indicated through a PC5 RRC connection between two UEs.

Referring to <FIG>, the UE may determine whether a new PC5 SLRB configuration is indicated in step <NUM> while a PC5 RRC connection is maintained in step <NUM>. When the new SLRB configuration is indicated according to the determination in step <NUM>, the UE may perform a new SLRB configuration procedure in step <NUM>. When a change in an SRC ID is indicated according to the determination in step <NUM>, the UE may perform an SRC ID change procedure for the conventional SLRB in step <NUM>. When a change in an SRC ID is not indicated according to the determination in step <NUM>, step <NUM> is repeated. Step <NUM> and step <NUM> may correspond to an internal procedure of one UE, which is a new SLRB configuration indication and an SRC ID change indication from an upper layer to an RRC layer, and may be a new SLRB configuration indication and an SRC ID change indication as a configuration through the PC5 RRC connection between two UEs connected through PC5 RRC unicast.

<FIG> may be performed by two UEs connected through sidelink unicast.

<FIG> illustrates a signal procedure for processing a source identifier update for sidelink according to an embodiment. This embodiment is however not covered by the claims.

Referring to <FIG>, UE #<NUM><NUM> and UE #<NUM><NUM> may have a PC5 RRC unicast connection in step <NUM>. SLRB configured through the PC5 RRC unicast connection may correspond to SLRB=<NUM>. SRC ID=<NUM> and DST ID=<NUM> on the side of UE #<NUM><NUM>, and SRC ID=<NUM> and DST ID=<NUM> on the side of UE #<NUM><NUM>. UE #<NUM><NUM> may determine the necessity for a new PC5 RRC unicast connection or the necessity for a new SLRB configuration in step <NUM>. UE #<NUM><NUM> and UE #<NUM><NUM> may perform the PC5 RRC unicast connection configuration and the new SLRB configuration in step <NUM> and step <NUM>. UE #<NUM><NUM> and UE #<NUM><NUM> may have SLRB <NUM> in step <NUM> through the procedures in step <NUM> and <NUM>.

In step <NUM>, UE #<NUM><NUM> may determine the necessity for a change in its own SRC ID for SLRB <NUM>, which is the DST ID of UE #<NUM><NUM>. UE #<NUM><NUM> and UE #<NUM><NUM> may perform a procedure for changing a DST ID of UE <NUM> (that is, an SRC ID of UE #<NUM>) for SLRB <NUM> in step <NUM> and step <NUM>. After step <NUM> and step <NUM>, UE #<NUM><NUM> and UE #<NUM><NUM> may configure SRC ID=<NUM> and DST ID=<NUM> on the side of UE #<NUM> and configure SRC ID=<NUM> and DST ID=<NUM> on the side of UE #<NUM> in accordance with SLRB <NUM> in step <NUM>.

A method of operating a sidelink logical channel priority (LCP) may include at least one of the following methods.

Method <NUM>: Priority information of a sidelink logical channel corresponding to a V2X packet or V2X flow may use a default priority level value of <NUM> QIs of the V2X packet or V2X flow. Examples of <NUM> QIs are shown in Table <NUM> below. A PQI which can be applied to V2X sidelink may be derived based on the <NUM> QIs, and the priority of the PQI may be configured to follow the default priority level value. Alternatively, the priority of the PQI may be configured based on the default priority level value.

An AS layer of the UE may determine the priority value of a logical channel corresponding to the V2X flow or V2X packet according to the priority level of the PQI of the V2X flow or V2X packet and execute the LCP according to the priority. For example, it is assumed that the priority is lower as the priority value is higher. A logical channel corresponding to V2X flow or a V2X packet having a high priority (having a low priority value) may be preferentially scheduled. PC5 RRC may have a higher priority than the V2X packet. Table <NUM> appears as follows.

Method <NUM>: V2X layer may configure a priority value which can be applied to a V2X packet or V2X flow. The operation of the priority value assigned to the V2X packet or V2X flow may follow the rule of an upper layer. An AS layer of the UE may determine the priority of a logical channel corresponding to the V2X flow or V2X packet based on a priority value of the V2X flow or V2X packet, and may execute the LCP according to the priority.

For example, it is assumed that the priority is lower as the priority value is higher. A logical channel corresponding to V2X flow or a V2X packet having a high priority (having a low priority value) may be preferentially scheduled. PC5 RRC may have a higher priority than the V2X packet.

A method of selecting sidelink resource pools to be used for the direct link setup between UEs of a higher layer and/or PC5 RRC connection setup between UEs may include at least one of the following methods.

Methods disclosed according to embodiments described herein may be implemented by hardware, software, or a combination of hardware and software.

The at least one program may include instructions that cause the electronic device to perform the methods according to embodiments of the disclosure.

Alternatively, any combination of some or all of these memories may form a memory in which the program is stored. A plurality of such memories may be included in the electronic device.

In addition, the programs may be stored in an attachable storage device which may access the electronic device through communication networks such as the Internet, Intranet, local area network (LAN), wide LAN (WLAN), and storage area network (SAN) or a combination thereof. A separate storage device on the communication network may access a portable electronic device.

Claim 1:
A method performed by a first user equipment, UE (<NUM>), in a wireless communication system, wherein the first UE (<NUM>) is in a radio resource control, RRC, connected state, the method comprising:
transmitting (<NUM>), to a base station, BS (<NUM>), a SidelinkUEInformation message including information related to a sidelink transmission, wherein the information includes a cast type, a destination identifier, a Quality of Service, QoS, flow identifier, QFI, and data rate information;
receiving (<NUM>), from the BS (<NUM>), an RRC Reconfiguration message including a radio link control, RLC, configuration, wherein the RLC configuration is configured based on the data rate information included in the SidelinkUEInformation message; and
performing (<NUM>) the sidelink communication with a second UE (<NUM>), based on the received RLC configuration.