Method and apparatus for supporting HARQ feedback transmission in a device-to-device communication system

Abstract

The present disclosure relates to a fifth-generation (5G) or Pre5G communication system for supporting higher data transmission rates than fourth-generation (4G) communication systems such as Long-Term Evolution (LTE). The present disclosure can be applied to intelligent services such as smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail enterprise, security and safety-related services, etc. based on 5G communication technology and IoT-related technology. In addition, a method for operating a terminal in a wireless communication system may include the steps of: determining service information required for a V2X application and determining a V2X transmission mode; determining QoS information for the service required by the V2X application; obtaining sidelink radio bearer configuration information corresponding to the QoS information; and transmitting and receiving V2X packets through a device-to-device communication method using the obtained sidelink radio bearer configuration information.

Description

Technical Field

[0001] The present disclosure generally relates to a wireless communication system, and more particularly, to an apparatus and method for supporting feedback signaling for data transmission of a direct communication bearer in a wireless communication system. Background Art

[0002] In order to meet the increasing wireless data traffic demand since the deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, 5G or pre-5G communication systems are also referred to as "Beyond 4G network" or "Post-LTE system".

[0003] The 5G communication system is considered to be implemented in a higher frequency (millimeter wave) band (e.g., 60 GHz band) in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antenna technologies are discussed in the 5G communication system.

[0004] In addition, in the 5G communication system, development of system network improvements is underway based on advanced small cells, cloud radio access network (RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, mobile network, cooperative communication, coordinated multi-point (CoMP), receiver interference cancellation, and so on.

[0005] In the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superimposed decoding (SWSC) as advanced coding modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access technologies have also been developed.

[0006] The Internet, which is a human - centric connectivity network in which humans generate and consume information, is now evolving into the Internet of Things (IoT), where distributed entities such as things exchange and process information without human intervention. The Internet of Everything (IoE) is the product of the combination of IoT technology and big - data processing technology through connection with cloud servers. Since IoT implementation requires technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", and "security technology", research has recently been conducted on sensor networks, machine - to - machine (M2M) communication, machine - type communication (MTC), etc. Such IoT environments can provide intelligent Internet technology services that create new value for human life by collecting and analyzing data generated between connected things. IoT can be applied to various fields through the integration and combined application of existing information technology (IT) and various industrial applications, including smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and advanced medical services.

[0007] Therefore, various efforts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine - type communication (MTC), and machine - to - machine (M2M) communication can be implemented through beamforming, MIMO, and array antennas. Cloud radio access network (RAN), as an application of the above - mentioned big - data processing technology, can also be considered an example of the integration of 5G technology and IoT technology.

[0008] For 5G systems, wireless interface schemes for providing services with various quality - of - service (QoS) requirements are being discussed. For example, a direct communication method for vehicle - to - everything (V2X) terminals has been proposed. In addition, various discussions are underway to shorten communication time, increase reliability, and effectively support device - to - device communication. SUMMARY OF THE INVENTION

[0009] TECHNICAL PROBLEM

[0010] Based on the above discussion, the present disclosure provides an apparatus and method for supporting data transmission and vehicle communication services, which achieve high - reliability and low - latency requirements by providing a method for performing a device - to - device communication scheme in a vehicle communication system.

[0011] SOLUTION TO THE PROBLEM

[0012] To solve the above problems, a method of a first terminal in a wireless communication system according to an embodiment of the present disclosure may include: sending data to a second terminal through a sidelink; identifying whether hybrid automatic repeat request (HARQ) feedback is enabled for the sidelink; and monitoring HARQ feedback information regarding the data if it is identified that HARQ feedback is enabled for the sidelink.

[0013] In addition, a first terminal in a wireless communication system according to an embodiment of the present disclosure may include: a transceiver; and a controller configured to: control the transceiver to send data to a second terminal via a sidelink; identify whether hybrid automatic repeat request (HARQ) feedback is enabled for the sidelink; and if it is identified that HARQ feedback is enabled for the sidelink, control the transceiver to monitor HARQ feedback information regarding the data. According to various embodiments of the present disclosure, an operating method of a terminal in a wireless communication system includes: determining, by the terminal, a V2X service that requires sidelink direct communication; determining quality of service (QoS) information required in the service; and obtaining reliability requirement or latency requirement information required in the service. The method includes controlling sidelink vehicle-to-everything (V2X) radio parameter configuration to send feedback signaling for transmitting a packet, so as to meet the reliability QoS requirement of the V2X service by using sidelink direct communication. The method includes controlling sidelink vehicle-to-everything (V2X) radio parameter configuration not to send feedback signaling for transmitting a packet, so as to meet the latency QoS requirement of the V2X service by using sidelink direct communication. Obtaining, by a terminal that sends or receives a V2X service based on direct communication, radio parameter configuration information for determining whether to send feedback signaling includes: sending QoS information of the service to a base station, and obtaining parameter configuration information to determine whether to send feedback signaling for a radio bearer of the service; obtaining, by the base station, parameter configuration information and using it as a system parameter to determine whether to send feedback signaling for a radio bearer corresponding to the QoS information, and obtaining the parameter configuration information by the terminal; and obtaining, by the terminal, parameter configuration information to determine whether to send feedback signaling for a radio bearer corresponding to pre-configured QoS information of the terminal.

[0014] According to various embodiments of the present disclosure, a terminal device in a wireless communication system according to various embodiments includes: a transceiver; and at least one processor that is functionally combined with the transceiver. If it is determined that the terminal is within the coverage of a base station, the at least one processor controls the terminal to: determine QoS information required in the V2X service; request parameter configuration information from the base station to determine whether to send feedback signaling for a radio bearer corresponding to the QoS information; and control the terminal to be assigned the parameter configuration information. If it is determined that the terminal is not within the coverage of the base station, the at least one processor controls the terminal to: determine QoS information required in the V2X service; and obtain parameter configuration information to determine whether to send feedback signaling for a radio bearer corresponding to the pre-configured QoS information.

[0015] According to various embodiments of the present disclosure, an operation method of a terminal in a wireless communication system may include: determining service information required for a V2X application and determining QoS information of a service required for the V2X application; obtaining parameter configuration information to determine whether to transmit feedback signaling for a sidelink radio bearer corresponding to the QoS information; and transmitting or receiving V2X packets in a direct communication scheme by using the obtained parameter configuration information of the sidelink radio bearer.

[0016] According to various embodiments of the present disclosure, a terminal in a wireless communication system may include: a transceiver configured to transmit or receive data; and at least one processor functionally coupled to the transceiver, wherein the at least one processor: determines service information required for a V2X application; determines QoS information of a service required for the V2X application; obtains parameter configuration information to determine whether to transmit feedback signaling for a sidelink radio bearer corresponding to the QoS information; and transmits or receives V2X packets in a direct communication scheme by using the obtained parameter configuration information of the sidelink radio bearer.

[0017] Advantages of the Invention

[0018] Various embodiments of the present disclosure provide an apparatus and a method capable of supporting vehicle communication services requiring various qualities of service (QoS) by using device-to-device communication in a vehicle communication system, thereby enabling the reliability and latency requirement values of vehicle communication to be achieved.

[0019] The effects obtainable through the present disclosure are not limited to the above effects, and those skilled in the art can clearly understand other effects not mentioned through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A wireless communication system according to various embodiments of the present disclosure is shown;

[0021] Figure 2 A configuration of a base station in a wireless communication system according to various embodiments of the present disclosure is shown;

[0022] Figure 3 A configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure is shown;

[0023] Figure 4a A configuration of a communication unit in a wireless communication system according to various embodiments of the present disclosure is shown;

[0024] Figure 4b An example according to various embodiments of the present disclosure is shown, in which an independent antenna array is independently used for each transmission path in an analog beamforming unit of a communication unit in a wireless communication system;

[0025] Figure 4c Examples according to various embodiments of the present disclosure are shown, where transmission paths in an analog beamforming unit of a communication unit in a wireless communication system share an antenna array;

[0026] Figure 5 Situations according to various embodiments of the present disclosure are shown, where device - to - device communication is performed by using sidelink radio access technology (RAT);

[0027] Figure 6a A signaling procedure according to various embodiments of the present disclosure is shown, which configures parameters for a terminal in the RRC - CONNECTED state to determine whether to send feedback signaling in device - to - device communication;

[0028] Figure 6b A signaling procedure according to various embodiments of the present disclosure is shown, which configures parameters for a terminal in the RRC - CONNECTED state to determine whether to send feedback signaling in device - to - device communication;

[0029] Figure 7a A signaling procedure according to various embodiments of the present disclosure is shown, which configures parameters for a terminal in the RRC - IDLE state or a terminal in the RRC - INACTIVE state to determine whether to send feedback signaling in device - to - device communication;

[0030] Figure 7b A signaling procedure according to various embodiments of the present disclosure is shown, which configures parameters for a terminal in the RRC - IDLE state or a terminal in the RRC - INACTIVE state to determine whether to send feedback signaling in device - to - device communication;

[0031] Figure 7c A signaling procedure according to various embodiments of the present disclosure is shown, which configures parameters for a terminal in the RRC - IDLE state or a terminal in the RRC - INACTIVE state to determine whether to send feedback signaling in device - to - device communication;

[0032] Figure 7d A signaling procedure according to various embodiments of the present disclosure is shown, which configures parameters for a terminal in the RRC - IDLE state or a terminal in the RRC - INACTIVE state to determine whether to send feedback signaling in device - to - device communication;

[0033] Figure 7eShows a signaling procedure according to various embodiments of the present disclosure, which configures parameters for determining whether to send feedback signaling in device-to-device communication for a terminal in the RRC-IDLE state or a terminal in the RRC-INACTIVE state;

[0034] Figure 8a Shows a signaling procedure according to various embodiments of the present disclosure, which configures parameters for determining whether to send feedback signaling in device-to-device communication for a terminal in the OUT-OF-COVERAGE state;

[0035] Figure 8b Shows a signaling procedure according to various embodiments of the present disclosure, which configures parameters for determining whether to send feedback signaling in device-to-device communication for a terminal in the OUT-OF-COVERAGE state;

[0036] Figure 9a Shows a signaling procedure according to various embodiments of the present disclosure, which configures parameters for determining whether to send feedback signaling between terminals transmitting and receiving V2X packets based on direct communication;

[0037] Figure 9b Shows a signaling procedure according to various embodiments of the present disclosure, which configures parameters for determining whether to send feedback signaling between terminals transmitting and receiving V2X packets based on direct communication;

[0038] Figure 9c Shows a signaling procedure according to various embodiments of the present disclosure, which configures parameters for determining whether to send feedback signaling between terminals transmitting and receiving V2X packets based on direct communication;

[0039] Figure 10a Shows the operations of a transmitting terminal according to various embodiments of the present disclosure;

[0040] Figure 10b Shows the operations of a receiving terminal according to various embodiments of the present disclosure;

[0041] Figure 11a Shows a signaling procedure between a terminal and a base station according to various embodiments of the present disclosure, which is used to process feedback signaling transmission resources;

[0042] Figure 11b Shows a signaling procedure between a terminal and a base station according to various embodiments of the present disclosure, which is used to process feedback signaling transmission resources;

[0043] Figure 11c Shows a signaling procedure between a terminal and a base station according to various embodiments of the present disclosure, which is used to process feedback signaling transmission resources;

[0044] Figure 12 A signal flow diagram showing a terminal transmitting HARQ feedback assistance information to a base station according to various embodiments of the present disclosure;

[0045] Figure 13 Operations according to various embodiments of the present disclosure are shown, in which a terminal selects sidelink resources by itself according to whether to transmit HARQ feedback; and

[0046] Figure 14 Operations of a terminal according to various embodiments of the present disclosure are shown. Detailed implementation manners

[0047] The terms used in the present disclosure are only for describing specific embodiments and are not intended to limit the present disclosure. Unless absolutely different in context, singular expressions may include plural expressions. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure pertains. These terms defined in a commonly used dictionary may be interpreted as having the same meaning as the context meaning in the relevant field, and should not be interpreted as having an ideal or overly formal meaning unless explicitly defined in the present disclosure. In some cases, even the terms defined in the present disclosure should not be interpreted as excluding embodiments of the present disclosure.

[0048] Hereinafter, various embodiments of the present disclosure will be described based on hardware methods. However, various embodiments of the present disclosure include technologies using both hardware and software, and thus various embodiments of the present disclosure may not exclude the software perspective.

[0049] Hereinafter, the present disclosure relates to an apparatus and method for obtaining configuration parameters, which are used to determine the transmission of feedback signaling of a sidelink radio bearer corresponding to the quality of service (QoS) requirements of vehicle-to-everything (V2X) communication services in a wireless communication system. The feedback signaling may include, for example, HARQ feedback. Specifically, the present disclosure provides a technology for meeting the QoS levels required by various V2X services based on a method for obtaining configuration parameters, where the configuration parameters are used to determine the transmission of feedback signaling of a sidelink radio bearer for direct sidelink communication between vehicle-to-everything (V2X) terminals in a wireless communication system.

[0050] In the following description, for ease of explanation, terms indicating signals, terms indicating channels, terms indicating control information, terms indicating network entities, and terms indicating elements of devices are exemplified. Therefore, the present disclosure is not limited to the following terms, and other terms with the same technical meaning may be used.

[0051] In addition, the present disclosure includes terms used in some communication protocols (e.g., the 3rd Generation Partnership Project (3GPP)) for explaining various embodiments, but these terms only correspond to examples. Various embodiments can also be easily modified and then applied to other communication systems.

[0052] Figure 1 A wireless communication system according to various embodiments of the present disclosure is shown. In Figure 1 it, base station 110, terminal 120, and terminal 130 are shown as parts of nodes using a wireless channel in the wireless communication system. Although Figure 1 only one base station is shown, another base station identical or similar to base station 110 may also be included. Although Figure 1 only two terminals are shown, another terminal identical or similar to terminal 120 and terminal 130 may also be included.

[0053] Base station 110 is a network infrastructure that provides wireless access to terminals 120 and 130. Base station 110 has a coverage area defined as a specific geographical area based on the distance within which the base station can transmit signals. Base station 110 may also be referred to as an "access point (AP)", "evolved Node B (eNB)", "5th Generation (5G) node", "5G base station (gNodeB or gNB)", "wireless point", "transmission / reception point (TRP)", or other terms having an equivalent technical meaning thereto.

[0054] Each of terminals 120 and 130 is a device used by a user and communicates with base station 110 via a wireless channel. In some cases, at least one of terminals 120 and 130 may operate without user participation. That is, at least one of terminals 120 and 130 is a device configured to perform machine type communication (MTC) and may not be carried by a user. Each of terminals 120 and 130 may be referred to as a "user equipment (UE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "user device", or other terms having an equivalent technical meaning thereto.

[0055] Base station 110 and terminals 120 and 130 may transmit and receive wireless signals in a sub 6GHz band and a millimeter wave (mmWave) band (e.g., 28GHz, 30GHz, 38GHz, or 60GHz). To improve the channel gain, base station 110 and terminals 120 and 130 may perform beamforming. Beamforming may include transmit beamforming and receive beamforming. That is, base station 110 and terminals 120 and 130 may provide directivity to transmitted signals or received signals. For this purpose, base station 110 and terminals 120 and 130 may select serving beams 112, 113, 121, and 131 through a beam search process or a beam management process. Communication after the selection of serving beams 112, 113, 121, and 131 may be performed on resources having a quasi co-location (QCL) relationship with the resources used for transmitting serving beams 112, 113, 121, and 131.

[0056] If the large-scale characteristics of a channel on which a symbol has been transmitted on a first antenna port can be inferred from a channel on which a symbol has been transmitted on a second antenna port, it may be considered that the first antenna port and the second antenna port have a QCL relationship therebetween. For example, the large-scale properties may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameters.

[0057] Figure 2 The configuration of a base station in a wireless communication system according to various embodiments of the present disclosure is shown. It may be considered that Figure 2 the shown configuration is the configuration of base station 110. The term “… unit” used hereinafter or the endings of words such as “…or(… device)” or “…er(… device)” may represent a unit that processes at least one function or operation, and it may be implemented by hardware, software, or a combination of hardware and software.

[0058] Referring Figure 2 , the base station includes a wireless communication unit 210, a backhaul communication unit 220, a storage unit 230, and a controller 240.

[0059] The wireless communication unit 210 performs the function of transmitting and receiving signals through a wireless channel. For example, the wireless communication unit 210 performs a conversion function between a baseband signal and a bit stream according to the physical layer protocol of the system. For example, when transmitting data, the wireless communication unit 210 generates complex symbols by encoding and modulating the transmitted bit stream. In addition, when receiving data, the wireless communication unit 210 reconstructs the received bit stream by demodulating and decoding the baseband signal.

[0060] Similarly, the wireless communication unit 210 up-converts a baseband signal to a radio frequency (RF) band signal and then transmits the converted RF band signal through an antenna, and down-converts the RF band signal received through the antenna to a baseband signal. For this purpose, the wireless communication unit 210 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), and an analog-to-digital converter (ADC), etc. Additionally, the wireless communication unit 210 may include multiple transmit / receive paths. Furthermore, the wireless communication unit 210 may include at least one antenna array configured with multiple antenna elements.

[0061] In terms of hardware, the wireless communication unit 210 may be configured with a digital unit and an analog unit, and the analog unit may include multiple sub-units according to operating power, operating frequency, etc. The digital unit may be implemented as at least one processor (e.g., a digital signal processor (DSP)).

[0062] The wireless communication unit 210 may transmit and receive signals as described above. Therefore, the whole or a part of the wireless communication unit 210 may be referred to as a "transmitter", "receiver", or "transceiver". Additionally, in the following description, the transmission and reception through a wireless channel may be understood to include the above-described processing performed by the wireless communication unit 210.

[0063] The backhaul communication unit 220 provides an interface to perform communication with other nodes within the network. That is, the backhaul communication unit 220 converts a bit stream sent from the base station to another node (e.g., another access node, another base station, an upper node, a core network, etc.) into a physical signal, and converts the physical signal received from another node into a bit stream.

[0064] The storage unit 230 stores data such as basic programs, application programs, and configuration information for the operation of the base station. The storage unit 230 may be configured as a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. The storage unit 230 provides the stored data according to the request of the controller 240.

[0065] The controller 240 controls the overall operation of the base station. For example, the controller 240 transmits and receives signals through the wireless communication unit 210 or the backhaul communication unit 220. Additionally, the controller 240 records data in and reads data from the storage unit 230. Furthermore, the controller 240 may perform the functions of a protocol stack required in a communication protocol. According to another embodiment, the protocol stack may be included in the wireless communication unit 210. For this purpose, the controller 240 may include at least one processor.

[0066] According to various embodiments, the controller 240 may send radio resource control (RRC) configuration information to the terminal 110. The controller 240 may send sidelink configuration information to the terminal 110. For example, the controller 240 may control the base station to perform operations according to various embodiments described later.

[0067] Figure 3 The configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure is shown. The Figure 3 configuration shown may be understood as the configuration of the terminal 120 or the terminal 130. The term “… unit” used hereinafter or the endings of words such as “…or (... device)” or “…er (... device)” may represent a unit that processes at least one function or operation, and it may be implemented by hardware, software, or a combination of hardware and software.

[0068] Referring to Figure 3 , the terminal includes a communication unit 310, a storage unit 320, and a controller 330.

[0069] The communication unit 310 performs the function of transmitting / receiving signals through a wireless channel. For example, the communication unit 310 performs the conversion function between a baseband signal and a bit stream according to the physical layer protocol of the system. For example, when transmitting data, the communication unit 310 generates complex symbols by encoding and modulating the transmitted bit stream. In addition, when receiving data, the communication unit 310 reconstructs the received bit stream by demodulating and decoding the baseband signal. In addition, the communication unit 310 up-converts the baseband signal to an RF band signal and then transmits the converted RF band signal through an antenna, and down-converts the RF band signal received through the antenna to a baseband signal. For example, the communication unit 310 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC, etc.

[0070] In addition, the communication unit 310 may include multiple transmit / receive paths. In addition, the communication unit 310 may include at least one antenna array that includes multiple antenna elements. In terms of hardware, the communication unit 310 may be configured as a digital circuit and an analog circuit (e.g., a radio frequency integrated circuit (RFIC)). The digital circuit and the analog circuit may be implemented in a single package. In addition, the communication unit 310 may include multiple RF chains. In addition, the communication unit 310 may perform beamforming.

[0071] In addition, the communication unit 310 may include different communication modules to process signals of different frequency bands. In addition, the communication unit 310 may include multiple communication modules to support a variety of different radio access technologies. For example, different radio access technologies may include low energy Bluetooth (BLE), Wi-Fi, Wi-Fi Gigabit (WiGig), and cellular networks (e.g., Long Term Evolution (LTE)), etc. Additionally, different frequency bands may include the Super High Frequency (SHF) (e.g., 2.5 GHz, 3.5 GHz, or 5 GHz) band and the millimeter (mm) wave (e.g., 60 GHz) band.

[0072] The communication unit 310 transmits and receives signals as described above. Therefore, the whole or a part of the communication unit 310 may be referred to as a "transmitter", "receiver", or "transceiver". In addition, in the following description, the transmission and reception through a wireless channel may be understood to include the above-described processing performed by the communication unit 310.

[0073] The memory 320 stores data such as basic programs, application programs, and configuration information for the operation of the terminal. The storage unit 320 may be configured as a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. The storage unit 320 provides the stored data according to the request of the controller 330.

[0074] The controller 330 controls the overall operation of the terminal. For example, the controller 330 transmits and receives signals through the communication unit 310. Additionally, the controller 330 records data in and reads data from the storage unit 320. In addition, the controller 330 may perform the functions of the protocol stack required in the communication protocol. To this end, the controller 330 may include at least one processor or microprocessor, or may be a part of a processor. In addition, a part of the controller 330 and the communication unit 310 may be referred to as a Communication Processor (CP).

[0075] According to various embodiments, when the terminal 120 performs sidelink direct communication with another terminal, the controller 330 may cause the terminal 120 to: determine service information required for the V2X application and determine QoS information for the V2X service; obtain configuration parameters required to determine whether to send feedback signaling for the sidelink radio bearer corresponding to the QoS information; and send or receive V2X packets in the direct communication scheme by using the obtained configuration information required to determine whether to send feedback signaling for the sidelink radio bearer. For example, the controller 330 may control the terminal to perform operations according to various embodiments described later.

[0076] Figures 4a to 4c The configuration of a communication unit in a wireless communication system according to various embodiments of the present disclosure is shown. Figures 4a to 4c Shown is Figure 2An example of the detailed configuration of the wireless communication unit 210 or Figure 3 the communication unit 310 shown. Specifically, Figures 4a to 4c elements configured to perform beamforming are shown, and these elements are Figure 2 part of the wireless communication unit 210 or Figure 3 the communication unit 310.

[0077] Referring to Figure 4a , the wireless communication unit 210 or the communication unit 310 includes an encoding and modulation unit 402, a digital beamforming unit 404, a plurality of transmission paths 406-1 to 406-N, and an analog beamforming unit 408.

[0078] The encoding and modulation unit 402 performs channel encoding. For channel encoding, at least one of a low-density parity-check (LDPC) code, a convolutional code, and a polar code can be used. The encoding and modulation unit 402 generates modulation symbols by performing constellation mapping.

[0079] The digital beamforming unit 404 performs beamforming on digital signals (e.g., modulation symbols). For this purpose, the digital beamforming unit 404 multiplies the beamforming weights by the modulation symbols. The beamforming weights are used to change the magnitude and phase of the signals and can be referred to as a "precoding matrix", a "precoder", etc. The digital beamforming unit 404 outputs the modulation symbols that have undergone digital beamforming to the plurality of transmission paths 406-1 to 406-N. According to the multiple-input multiple-output (MIMO) transmission scheme, the modulation symbols can be multiplexed, or the same modulation symbols can be provided to the plurality of transmission paths 406-1 to 406-N.

[0080] The plurality of transmission paths 406-1 to 406-N convert the digital signals that have undergone digital beamforming into analog signals. For this purpose, each of the plurality of transmission paths 406-1 to 406-N may include an inverse fast Fourier transform (IFFT) operator, a cyclic prefix (CP) inserter, a DAC, and an up-conversion converter. The CP inserter is designed for the orthogonal frequency-division multiplexing (OFDM) scheme and can be excluded in cases where different physical layer schemes (e.g., filter bank multicarrier (FBMC)) are applied. That is, the plurality of transmission paths 406-1 to 406-N respectively provide independent signal processing processes for the plurality of streams generated by digital beamforming. However, according to the implementation method, a part of the elements of each of the plurality of transmission paths 406-1 to 406-N can be shared.

[0081] The analog beamforming unit 408 performs beamforming on the analog signals. For this purpose, the digital beamforming unit 404 multiplies the beamforming weights by the analog signals. The beamforming weights are used to change the magnitude and phase of the signals. Specifically, according to the connection structure between the plurality of transmission paths 406-1 to 406-N and the antennas, the analog beamforming unit 408 can be configured as Figure 4b or as Figure 4c shown.

[0082] Refer to Figure 4b . The signals input to the analog beamforming unit 408 undergo phase / magnitude conversion and amplification operations, and then are transmitted through the antennas. The signals in the transmission paths are transmitted through different antenna groups, i.e., the antenna array. Regarding the processing of the signals input through the first path, the signals are converted by the phase / magnitude converters 412-1-1 to 412-1-M into a signal stream including signals having the same phase or magnitude or different phases or magnitudes, and the converted signal stream is amplified by the amplifiers 414-1-1 to 414-1-M, and then the amplified signal stream is transmitted through the antennas respectively.

[0083] Refer to Figure 4c . The signals input to the analog beamforming unit 408 undergo phase / magnitude conversion and amplification operations, and then are transmitted through the antennas. The signals in the transmission paths are transmitted through the same antenna group (i.e., the antenna array). Regarding the processing of the signals input through the first path, the signals are converted by the phase / magnitude converters 412-1-1 to 412-1-M into a signal stream including signals having the same phase or magnitude or different phases or magnitudes, and the converted signals are amplified by the amplifiers 414-1-1 to 414-1-M. In order to transmit through a single antenna array, the amplified signals are added together by the adders 416-1 to 416-M based on the antenna elements, and then the added signals are transmitted through the antennas respectively.

[0084] Figure 4b shows an example in which independent antenna arrays are used for each transmission path, and Figure 4c shows an example in which one antenna array is shared by the transmission paths. However, according to another embodiment, some of the transmission paths may use independent antenna arrays, while the remaining transmission paths may share a single antenna array. In addition, according to yet another embodiment, a switchable structure between the transmission paths and the antenna arrays may be applied, thereby allowing a structure that can be adaptively changed according to the situation.

[0085] V2X services can be classified into basic safety services and advanced services. In addition to vehicle notification (CAM or BSM) services, basic safety services can also correspond to detailed services such as left turn notification service, forward collision warning service, emergency vehicle lane notification service, forward obstacle warning service, and intersection traffic light information service, and can send or receive V2X information by using broadcast, unicast, or multicast transmission schemes. Compared with basic safety services, advanced services not only have enhanced QoS requirements but also require a method capable of sending or receiving V2X information by using unicast and multicast transmission schemes instead of broadcast transmission schemes, thereby allowing V2X information to be sent or received among a specific group of vehicles or between two vehicles. According to the enhanced QoS requirements, a method capable of sending feedback signaling for transmission packets is needed for services requiring high reliability. Advanced services can correspond to detailed services such as platooning service, autonomous driving service, remote driving service, and extended sensor-based V2X service.

[0086] For V2X services, the UE can perform V2X services in the ng-RAN or E-UTRAN by connecting to the ng-RAN (gNB) connected to the 5G core network or the E-UTRAN (ng-eNB) connected to the 5G core network. In another embodiment, in a case where the base station (ng-RAN or ng-eNB) is connected to the evolved packet core network (EPC), V2X services can be performed by the base station. In yet another embodiment, in a case where the base station (eNB) is connected to the evolved packet core network (EPC), V2X services can be performed by the base station. The V2X radio interface communication scheme available for device-to-device communication can correspond to at least one of unicast, multicast, and broadcast, and when performing V2X transmission or reception in each of the communication schemes in the communication scheme, a method for managing and configuring radio communication parameters suitable for the QoS requirements of V2X services needs to be provided.

[0087] A system for performing device-to-device communication based on LTE wireless communication defines a transmitting terminal to select and operate the parameters required for the terminal itself to transmit. When using LTE wireless communication, V2X service messages for basic safety are transmitted in the device-to-device communication scheme. The QoS requirements for basic safety V2X services are not strict, and even though there are various basic safety services, their QoS requirements are not diverse, and the differences between services are not significant. Therefore, even in a mode where the base station schedules the radio resources to be used in device-to-device communication based on LTE wireless communication and operates in such a way that the base station schedules radio resources without obtaining specific QoS requirement information for V2X services, the terminal randomly manages and configures the parameters.

[0088] Advanced V2X services have various QoS requirements, and there are significant differences among the QoS levels required for V2X services. In the case of a specific advanced V2X service, the service can only operate when the radio resources and radio parameter configurations for direct communication are configured to meet the strict QoS requirements of the service. Therefore, compared with traditional systems, a method for guaranteeing service QoS is needed for a device-to-device communication-based system that supports advanced V2X services. For example, the QoS levels of reliability and latency required by the service are different. Therefore, in order to guarantee the required QoS level, the configuration parameters of the direct communication radio bearer need to be operated.

[0089] In the present disclosure, a method will be described that determines QoS information corresponding to a side-link radio access bearer for a direct vehicle-to-vehicle communication scheme required to perform a basic security service or an advanced service according to various embodiments, and obtains configuration parameters for determining a feedback transmission corresponding to the QoS information.

[0090] Figure 5 Scenarios according to various embodiments of the present disclosure are shown, in which device-to-device communication is performed by using a side-link RAT.

[0091] Figure 5 (a) shows a scenario in which a terminal within the gNB coverage performs direct communication. In Figure 5 (a), the configuration parameter information for determining the feedback signaling for the side-link radio bearer used to send or receive V2X packets based on unicast, broadcast, and multicast among terminals can be pre-configured, or the configuration parameter information can be sent through an RRC dedicated message or a system information message of the gNB. The terminal performing direct communication can send QoS information corresponding to the V2X service to the base station and can obtain the configuration parameter information for determining the feedback signaling for the side-link radio bearer from the base station. The terminal performing direct communication can determine the QoS information corresponding to the V2X service and can obtain the parameters for determining the feedback signaling for the side-link radio bearer from the pre-configured information.

[0092] Figure 5 (b) shows a scenario in which a terminal within the ng-eNB coverage performs direct communication. In Figure 5In (b) thereof, configuration parameter information of a sidelink radio bearer for transmitting or receiving V2X packets based on unicast, multicast or broadcast between terminals can be pre-configured, or the configuration parameter information can be sent through an RRC dedicated message or a system information message of the ng-eNB. A terminal performing direct communication can send QoS information corresponding to the V2X service to the ng-eNB, and can obtain configuration parameter information of feedback signaling for determining whether to send a sidelink radio bearer from the base station. A terminal performing direct communication can determine QoS information corresponding to the V2X service, and can obtain parameters for determining whether to send feedback signaling for the sidelink radio bearer from pre-configured information.

[0093] Figure 5 Figure (c) shows a scenario where a terminal 120 within the coverage of the gNB and a terminal 130 within the coverage of the eNB perform direct communication. Configuration parameter information of a sidelink radio bearer for transmitting or receiving V2X packets based on unicast, multicast or broadcast between terminals can be pre-configured, or the configuration parameter information can be sent through an RRC dedicated message or a system information message of the gNB. A terminal performing direct communication can send QoS information corresponding to the V2X service to the gNB, and can obtain configuration parameter information of feedback signaling for determining whether to send a sidelink radio bearer from the base station. A terminal performing direct communication can determine QoS information corresponding to the V2X service, and can obtain parameters for sending feedback signaling for the sidelink radio bearer from pre-configured information.

[0094] Figure 5 Figure (d) shows a scenario where terminals within the coverage of the eNB perform direct communication. Configuration parameter information of a sidelink radio bearer for transmitting or receiving V2X packets based on unicast, multicast or broadcast between terminals can be pre-configured, or the configuration parameter information can be sent through an RRC dedicated message or a system information message of the eNB. A terminal performing direct communication can determine QoS information corresponding to the V2X service, and can obtain configuration parameter information of feedback signaling for determining whether to send a sidelink radio bearer from the base station. A terminal performing direct communication can determine QoS information corresponding to the V2X service, and can obtain parameters for sending feedback signaling for the sidelink radio bearer from pre-configured information.

[0095] According to various embodiments of the present disclosure, a method for obtaining sidelink QoS information related to a sidelink for performing device-to-device communication and obtaining configuration parameters for feedback signaling for transmitting a sidelink radio bearer corresponding to the QoS can be used in unicast V2X message transmission or reception, broadcast V2X message transmission or reception, or groupcast V2X message transmission or reception. According to various embodiments of the present disclosure, configuration parameters for transmitting feedback signaling for a sidelink radio bearer for performing device-to-device communication can be obtained by at least one of a method for obtaining configuration parameters from a base station, a method for a terminal to obtain preconfigured information, and a method for a terminal to randomly configure configuration parameters.

[0096] According to various embodiments of the present disclosure, the configuration for determining feedback signaling transmission can be determined by at least one or a combination of the following.

[0097] (1) Whether to send feedback signaling can be specified for each cell. For example, if configured to send feedback signaling in cell A, a terminal performing device-to-device communication in cell A can send feedback signaling. For example, if configured not to send feedback signaling in cell B, a terminal performing device-to-device communication in cell B can refrain from sending feedback signaling. Whether a terminal sends feedback signaling in the corresponding cell follows an indicator sent by the base station.

[0098] (2) Whether to send feedback signaling can be specified for each region. The region can operate independently of the cell. The terminal can determine the region based on the terminal's location information. If configured to always be able to send feedback signaling in region A, a terminal performing device-to-device communication in region A can send feedback signaling. If configured not to send feedback signaling in region B, a terminal performing device-to-device communication in region B can refrain from sending feedback signaling. Whether a terminal sends feedback signaling in the corresponding region can follow an indicator sent by the base station or follow preconfigured indication information in the terminal.

[0099] (3) Whether to send feedback signaling can be specified for each group. If configured to send feedback signaling for device-to-device communication in group A, terminals in group A can send feedback signaling. If configured not to send feedback signaling for device-to-device communication in group B, terminals in group B can refrain from sending feedback signaling. The terminal can obtain indication information indicating whether to send feedback signaling through group configuration information. The group configuration information is received from the base station, received from terminals belonging to the group, or preconfigured. The group configuration information including the indication information indicating whether to send feedback signaling can be sent to terminals in the group through one-time signaling.

[0100] (4) Whether to send feedback signaling can be configured for each V2X application. For example, if the feedback signaling for Application A is configured to be sent, then when device-to-device communication of Application A is performed, the terminal can always send feedback signaling. If the feedback signaling for Application B is configured not to be sent, then when device-to-device communication of Application B is performed, the terminal may not always send feedback signaling. The terminal can receive information about the V2X applications for which feedback signaling is to be sent and information about the V2X applications for which feedback signaling is not to be sent from the base station, or the same information can be pre-configured for the terminal. Alternatively, the terminal can obtain information indicating whether to send feedback signaling about the V2X application at a higher layer of the terminal (e.g., the application layer or the V2X layer).

[0101] (5) It is configured to send feedback signaling to meet the reliability requirements of the V2X application. For example, if reliability requirements are indicated for the V2X application, feedback signaling for the corresponding application packet can be configured to be sent. As another example, if it is indicated that the reliability requirements of the V2X application meet a specific threshold or higher, feedback signaling for the corresponding application packet can be configured to be sent. As yet another example, if it is indicated that the reliability requirements of the V2X application take precedence over the latency requirements, feedback signaling for the corresponding application packet can be configured to be sent.

[0102] (6) It is configured not to send feedback signaling to meet the latency requirements of the V2X application. For example, if latency requirements are indicated for the V2X application, feedback signaling for the corresponding application packet can be configured not to be sent. As another example, if it is indicated that the latency requirements of the V2X application meet a specific threshold or higher, feedback signaling for the corresponding application packet can be configured not to be sent. As yet another example, if it is indicated that the latency requirements of the V2X application take precedence over the reliability requirements, feedback signaling for the corresponding application packet can be configured not to be sent.

[0103] The relationship between whether to send feedback signaling and the reliability requirements or latency requirements is as follows. If feedback signaling can be sent, it can be determined whether the reception of the packet fails, and the packet can be re-sent. Therefore, reliability can be improved. If feedback signaling can be sent, it may take time to determine whether the reception of the packet fails and re-send the packet. Therefore, latency may increase. If feedback signaling cannot be sent, it is not necessary to determine whether the reception of the packet fails, and it is not necessary to re-send the packet. Therefore, latency may not increase. If feedback signaling cannot be sent, it is not necessary to determine whether the reception of the packet fails, and the packet is not re-sent. Therefore, reliability may be reduced.

[0104] According to an embodiment of the present disclosure, a parameter indicating a reliability requirement value may be configured as ProSe 5QI Reliability (PQI_R). PQI_R may represent the reliability level required for V2X applications. PQI_R may correspond to a parameter managed at a higher layer (e.g., application layer or V2X layer) of the terminal.

[0105] According to an embodiment of the present disclosure, a parameter indicating a latency requirement value may be configured as ProSe 5QI Latency (PQI_L). PQI_L may represent the latency level required for V2X applications. PQI_L may correspond to a parameter managed at a higher layer (e.g., application layer or V2X layer) of the terminal.

[0106] The QoS requirements (ProSe QoS indicator; PQI) of V2X services / applications according to embodiments of the present disclosure may be represented by standardized 5QI values defined in 3GPP standards, as shown in [Table 1]. For example, a case may be considered where a parameter indicating a reliability requirement value or a latency requirement value corresponds to the packet error rate or packet delay budget of the 5QI defined in [Table 1]. The terminal may configure the reliability requirement value or latency requirement value required in the V2X service based on the 5QI value.

[0107] [Table 1]

[0108]

[0109] In an embodiment of the present disclosure, the terminal may provide a base station with a reliability requirement value or a latency requirement value corresponding to a radio bearer for a V2X application, which value corresponds to a 5QI value. The terminal and the base station may obtain information on the reliability requirement value or latency requirement value corresponding to the 5QI value from a V2X server.

[0110] In another embodiment of the present disclosure, the terminal may provide a base station with a reliability requirement value (PQI_R) or a latency requirement value (PQI_L) corresponding to a radio bearer for a V2X application.

[0111] Parameters for determining whether to send feedback signaling include at least one of a feedback signaling transmission / feedback signaling non-transmission indicator (HARQ feedback enable / disable indicator), a reliability threshold, or a latency threshold. If a feedback signaling transmission indicator is configured, the terminal may send or receive a feedback signal for a packet transmitted in a direct communication scheme. If a feedback signaling non-transmission indicator is configured, the terminal may not send or receive a feedback signal for a packet transmitted in a direct communication scheme. If a reliability threshold or a latency threshold is configured, the terminal may determine whether the terminal may send or receive a feedback signal or may not send or receive a feedback signal for a packet transmitted in a direct communication scheme according to at least one or a combination of the conditions in [Table 2] below.

[0112] [Table 2]

[0113]

[0114] Examples of terminal operations for the above conditions are as follows. In addition to the examples below, combinations of various conditions are also possible.

[0115] If condition (a) is satisfied, feedback signaling is sent.

[0116] If condition (b) is satisfied, feedback signaling is not sent.

[0117] If condition (a) is satisfied and condition (b) is not satisfied, feedback signaling is sent.

[0118] If condition (a) is not satisfied and condition (b) is satisfied, feedback signaling is not sent.

[0119] If condition (c) is satisfied, feedback signaling is sent.

[0120] If condition (d) is satisfied, feedback signaling is not sent.

[0121] If condition (e) is satisfied, feedback signaling is sent.

[0122] If condition (h) is satisfied, feedback signaling is sent.

[0123] If condition (e) is satisfied and condition (a) is satisfied, feedback signaling is sent.

[0124] If condition (f) is satisfied and condition (b) is satisfied, feedback signaling is not sent.

[0125] The parameters used to determine whether to send feedback signaling can be configured via Uu signaling between the terminal and the base station, can be pre-configured for the terminal in advance, or can be configured via sidelink signaling between terminals.

[0126] - Classification based on the RRC connection state of the terminal

[0127] - RRC_Connected UEs obtain it via RRC dedicated signaling from the base station (e.g., without RRC_Reconfiguration)

[0128] - RRC_Idle / RRC_Inactive UEs obtain it from the V2X SIB

[0129] - RRC_Idle / RRC_Inactive UEs can also obtain it via RRC dedicated signaling from the base station.

[0130] - UEs outside the coverage obtain it via pre-configuration

[0131] - Method of using signaling in device - to - device communication (method in which a transmitting terminal notifies a receiving terminal or terminals belonging to a group to notify each other)

[0132] - PC5 RRC signaling (e.g., AS configuration or SLRB configuration)

[0133] - PC5 MAC signaling (e.g., MAC CE defined for PC5 configuration)

[0134] - PC5 PHY signaling (PSCCH SCI)

[0135] Next, referring to Figure 6a and Figure 6b , a method for configuring a terminal in the RRC - CONNECTED state with parameters for determining whether to send feedback signaling in device - to - device communication will be described.

[0136] Referring to Figure 6a , UE1 600 and UE2 650 can send or receive V2X packets through unicast - based device - to - device communication. In operation 611, UE1 600 and UE2 605 can configure a PC5 unicast connection for this purpose. In operation 612, UE1 600 can send a SidelinkUEInformation message including unicast flow information to the base station. Operation 612 can correspond to an operation of requesting side - link radio bearer (SLRB) configuration information required for device - to - device communication, and according to an embodiment of the present disclosure, this operation can be used to request configuration information to determine whether feedback signaling needs to be performed for the corresponding flow. The information that can be included in the signaling of operation 612 can include at least one of the following [Table 3].[[]END]

[0137] [Table 3]

[0138]

[0139]

[0140] In a system where the base station already has requirement value information corresponding to the V2X application, PQI, PQI_L, or PQI_R may not be included in operation 612.

[0141] When the base station receives information about the V2X application at operation 612, at operation 613, the base station may send configuration information to the terminal, and the configuration information allows determining whether to perform feedback signaling on packets belonging to the V2X application. Operation 613 may correspond to an operation of providing the SLRB configuration required for device-to-device communication, and in an embodiment of operation 613, the configuration information may include threshold information that allows determining whether to perform feedback signaling. The threshold information for determining whether to perform feedback signaling corresponding to the V2X application may include at least one of the following [Table 4].

[0142] [Table 4]

[0143]

[0144] In operation 613, a terminal that has received the configuration information (threshold) allowing determining whether to send feedback signaling may determine whether to send feedback signaling by comparing the configuration information with the reliability requirement value or delay requirement value of the packet (or flow). The conditions for determining whether to send feedback signaling are as shown in the above [Table 2].

[0145] Reference Figure 6b , UE1 600 and UE2 650 may send or receive V2X packets through unicast-based device-to-device communication. In operation 621, UE1 600 and UE2 650 may configure a PC5 unicast connection for this purpose. In operation 622, UE1 600 may send a SidelinkUEInformation message including unicast flow information to the base station 660. Operation 622 may correspond to an operation of requesting the SLRB configuration information required for device-to-device communication, and according to an embodiment of the present disclosure, this operation may be used to request configuration information to determine whether feedback signaling needs to be performed for the corresponding flow. The information that may be included in the signaling of operation 622 may include at least one of the above [Table 3].

[0146] In a system where the base station 660 already has the requirement value information corresponding to the V2X application, PQI, PQI_L, or PQI_R may not be included in operation 622.

[0147] When the base station 660 receives information about the V2X application at operation 622, at operation 623, the base station may send configuration information to the terminal, and the configuration information allows determining whether to perform feedback signaling on packets belonging to the V2X application. Operation 623 may correspond to an operation of providing the SLRB configuration required for device-to-device communication, and in an embodiment of operation 623, the configuration information may include indicator information that allows determining whether to perform feedback signaling. In Figure 6bIn an embodiment, the base station 660 may determine whether to perform feedback signaling based on demand value information corresponding to a V2X application and may configure an indicator.

[0148] The indicator information for determining whether to perform feedback signaling corresponding to a V2X application may include at least one of the following [Table 5].

[0149] [Table 5]

[0150]

[0151]

[0152] In operation 623, a terminal that has received configuration information (indicator) allowing determination of whether to send feedback signaling may determine whether to send feedback signaling for a packet (or flow) based on the configuration information. In an embodiment, the terminal may follow, without change, the configuration information determined by the base station 660 regarding whether to send feedback signaling. In another embodiment, the terminal may determine whether to send feedback signaling by considering sidelink state information and the configuration information (determined by the base station 660) regarding whether to send feedback signaling.

[0153] Next, referring to Figures 7a to 7e , a method for configuring parameters for determining whether to send feedback signaling in device-to-device communication for a terminal in the RRC_IDLE state or a terminal in the RRC_INACTIVE state will be described.

[0154] Referring to Figure 7a , UE1 700 and UE2 750 may send or receive V2X packets through unicast-based device-to-device communication. In operation 701, UE1 700 and UE2 750 may configure a PC5 unicast connection for this. In operation 702, UE1 700 may receive a V2X system information block (SIB) message sent by the base station 760. The V2X SIB message may include SLRB configuration information required for device-to-device communication, and according to an embodiment of the present disclosure, this message may be used to send configuration information for determining whether feedback signaling needs to be performed for a sidelink flow or sidelink packet corresponding to a V2X application. The information that may be included in the signaling in operation 702 may include at least one of the above [Table 4]. In operation 702, a terminal that has received configuration information (threshold) allowing determination of whether to send feedback signaling may determine whether to send feedback signaling by comparing the configuration information with the reliability requirement value or delay requirement value of the packet (or flow). The conditions for determining whether to send feedback signaling are as shown in the above [Table 2].

[0155] Referring to Figure 7b, UE1 700 and UE2 750 can send or receive V2X packets through unicast-based device-to-device communication. In operation 711, UE1 700 and UE2 750 can configure a PC5 unicast connection for this purpose. In operation 712, UE1 700 can receive a V2X SIB message sent by base station 760. The V2X SIB message may include SLRB configuration information required for device-to-device communication, and according to an embodiment of the present disclosure, this message can be used to send configuration information to determine whether feedback signaling needs to be performed for a sidelink flow or sidelink packet corresponding to a V2X application. In an embodiment of operation 712, the configuration information may include indicator information that allows determination of whether to perform feedback signaling. In Figure 7b an embodiment, base station 760 can determine whether to perform feedback signaling based on demand value information corresponding to the V2X application, and can configure the indicator. The indicator information for determining whether to perform feedback signaling corresponding to the V2X application may include at least one of the above [Table 5].

[0156] In operation 712, a terminal that has received configuration information (indicator) allowing determination of whether to send feedback signaling can determine whether to send feedback signaling for a packet (or flow) based on the configuration information. In an embodiment, the terminal can follow the configuration information determined by base station 760 regarding whether to send feedback signaling without change. In another embodiment, the terminal can determine whether to send feedback signaling by considering sidelink state information and the configuration information determined by base station 760 regarding whether to send feedback signaling.

[0157] In another embodiment of configuring whether to send feedback signaling corresponding to the V2X application for an RRC_IDLE terminal or an RRC_INACTIVE terminal, base station 760 can use RRC dedicated signaling to indicate the configuration information to be used by the terminal after transitioning from the RRC_CONNECTED state to the RRC_IDLE state or the RRC_INACTIVE state. Reference will be made to Figures 7c to 7e describe an embodiment of providing configuration information through RRC dedicated signaling to determine whether to send feedback signaling, which will be used in the RRC_IDLE state or the RRC_INACTIVE state.

[0158] Reference Figure 7c, UE1 700 and UE2 750 can send or receive V2X packets through unicast-based device-to-device communication. In operation 721, UE1 700 and UE2 750 can configure a PC5 unicast connection for this purpose. The base station 760 can indicate that an RRC_CONNECTED terminal transitions to the RRC_IDLE state or the RRC_INACTIVE state by sending RRC release signaling. According to an embodiment of the present disclosure, the RRC release signaling of operation 722 can include SLRB configuration information required for the direct communication of the terminal, and can be used to send configuration information to determine whether feedback signaling needs to be performed for a sidelink flow or sidelink packet corresponding to a V2X application. The information that can be included in the RRC release signaling of operation 722 can include at least one of the above [Table 4].

[0159] The terminal that has received the RRC release signaling of operation 722 can transition to the RRC_IDLE state or the RRC_INACTIVE state, and when performing device-to-device communication in the RRC_IDLE state or the RRC_INACTIVE state, the terminal can determine whether to send feedback signaling by comparing the reliability requirement value or delay requirement value of a packet (or flow) based on the configuration information (threshold) that allows determining whether to send feedback signaling received in operation 722. The conditions for determining whether to send feedback signaling are as shown in the above [Table 2].

[0160] According to an embodiment of the present disclosure, the configuration information that allows determining whether to send feedback signaling received in operation 722 can be applied only to new V2X applications other than the V2X applications already used by terminals in the RRC_CONNECTED state. According to another embodiment, the configuration information that allows determining whether to send feedback signaling received in operation 722 can be applied to new V2X applications and V2X applications already used by terminals in the RRC_CONNECTED state.

[0161] Reference Figure 7d, UE1 700 and UE2 750 can send or receive V2X packets through unicast-based device-to-device communication. In operation 731, UE1 700 and UE2 750 can configure a PC5 unicast connection for this purpose. The base station 760 can instruct an RRC_CONNECTED terminal to transition to the RRC_IDLE state or the RRC_INACTIVE state by sending RRC release signaling. According to an embodiment of the present disclosure, the RRC release signaling in operation 732 can include SLRB configuration information required for the direct communication of the terminal, and can be used to send configuration information to determine whether feedback signaling needs to be performed for a sidelink flow or a sidelink packet corresponding to a V2X application. In an embodiment of operation 732, the configuration information can include indicator information that allows determination of whether to perform feedback signaling. In Figure 7d the embodiment, the base station 760 can determine whether to perform feedback signaling based on demand value information corresponding to the V2X application, and can configure the indicator. The indicator information used to determine whether to perform feedback signaling corresponding to the V2X application can include at least one of the above [Table 5].

[0162] A terminal that has received the RRC release signaling in operation 732 can transition to the RRC_IDLE state or the RRC_INACTIVE state, and when performing device-to-device communication in the RRC_IDLE state or the RRC_INACTIVE state, the terminal can determine whether to send feedback signaling for a packet (or flow) based on the configuration information (indicator) received in operation 732 that allows determination of whether to send feedback signaling. In an embodiment, the terminal can follow the configuration information determined by the base station 760 regarding whether to send feedback signaling without change. In another embodiment, the terminal can determine whether to send feedback signaling by considering the sidelink state information and the configuration information determined by the base station 760 regarding whether to send feedback signaling.

[0163] According to an embodiment of the present disclosure, the configuration information received in operation 732 that allows determination of whether to send feedback signaling can be applied only to new V2X applications other than the V2X applications already used by a terminal in the RRC_CONNECTED state. According to another embodiment, the configuration information received in operation 732 that allows determination of whether to send feedback signaling can be applied to new V2X applications and the V2X applications already used by a terminal in the RRC_CONNECTED state.

[0164] Reference Figure 7e, UE1 700 and UE2 750 may send or receive V2X packets through unicast-based device-to-device communication. In operation 741, UE1 700 and UE2 750 may configure a PC5 unicast connection for this purpose. In another embodiment that provides configuration information for determining whether to send feedback signaling for a V2X application used by a terminal in the RRC_IDLE state or the RRC_INACTIVE state, in operation 742, the base station 760 may instruct the RRC_CONNECTED terminal to report information about the V2X application. As in Figure 6a or Figure 6b In the embodiment of, the terminal may send information about the V2X application to the base station 760 in operation 743. As in Figure 6a or Figure 6b In the embodiment of, the base station 760 may provide configuration information in operation 744 regarding whether to send feedback signaling corresponding to the V2X application. In operation 745, the base station 760 may send an RRC release message to allow the terminal to transition to the RRC_IDLE state or the RRC_INACTIVE state. According to various embodiments, operation 745 may be omitted, or the signaling of operation 744 and the signaling of operation 745 may be combined. The terminal may determine whether to send feedback signaling for the flow / packets of the V2X application based on device-to-device communication performed in the RRC_IDLE state or the RRC_INACTIVE state according to the configuration information received in operation 744.

[0165] According to an embodiment of the present disclosure, the configuration information received in operation 744 that allows determination of whether to send feedback signaling may be applied only to new V2X applications other than the V2X applications already used by the terminal in the RRC_CONNECTED state. According to another embodiment, the configuration information received in operation 744 that allows determination of whether to send feedback signaling may be applied to new V2X applications and the V2X applications already used by the terminal in the RRC_CONNECTED state.

[0166] According to an embodiment of the present disclosure, in a case where the configuration information regarding whether to send feedback signaling corresponding to the V2X application is obtained through a V2X SIB message and obtained through RRC dedicated signaling, the terminal may be operated based on the configuration information obtained through the RRC dedicated signaling.

[0167] Next, referring to Figure 8a and Figure 8b , a method for configuring parameters for determining whether to send feedback signaling in device-to-device communication for a terminal in the OUT-OF-COVERAGE state will be described.

[0168] Referring toFigure 8a UE1 800 and UE2 850 may send or receive V2X packets through unicast-based device-to-device communication. In operation 801, UE1 800 and UE2 850 may configure a PC5 unicast connection for this purpose. In operation 802, the terminal may perform device-to-device communication by using the configuration information preconfigured for the V2X application. According to an embodiment of the present disclosure, the preconfigured configuration information may include configuration information for determining whether feedback signaling needs to be performed for a sidelink flow or sidelink packet corresponding to the V2X application. The information preconfigured for determining whether feedback signaling needs to be performed may include at least one of the above [Table 4]. In operation 802, the terminal may determine whether to send feedback signaling by comparing the reliability requirement value or delay requirement value of the packet (or flow) based on the configuration information (threshold) that allows determining whether to send feedback signaling. The conditions for determining whether to send feedback signaling are as shown in the above [Table 2].

[0169] Reference Figure 8b UE1 800 and UE2 850 may send or receive V2X packets through unicast-based device-to-device communication. In operation 811, UE1 800 and UE2 850 may configure a PC5 unicast connection for this purpose. In operation 812, the terminal may perform device-to-device communication by using the configuration information preconfigured for the V2X application. According to an embodiment of the present disclosure, the preconfigured configuration information may include configuration information for determining whether feedback signaling needs to be performed for a sidelink flow or sidelink packet corresponding to the V2X application. The information preconfigured for determining whether feedback signaling needs to be performed may include at least one of the above [Table 5]. In operation 812, the terminal may determine whether to send feedback signaling for the packet (or flow) based on the configuration information (indicator) that allows determining whether to send feedback signaling.

[0170] According to an embodiment of the present disclosure, in a case where configuration information on whether to send feedback signaling corresponding to the V2X application is obtained through preconfiguration and obtained through signaling from the base station, the terminal may be operated based on the configuration information obtained through the signaling from the base station.

[0171] Next, with reference to Figures 9a to 9c a method for configuring a parameter for determining whether to send feedback signaling between terminals that perform V2X packet transmission or reception based on direct communication will be described.

[0172] The configuration information of the feedback signaling for determining whether to send a sidelink flow or a sidelink packet proposed in the present disclosure can be exchanged between terminals via signaling. The configuration information for determining whether to send feedback signaling can be sent from a transmitting terminal to a receiving terminal. The configuration information can be sent from a group leader terminal to a group member terminal. The configuration information sent or received between terminals can include at least one of the parameters shown in [Table 6] or [Table 7]. Based on Figures 6a to 8b the method, the determination of whether to send feedback signaling can be performed by a terminal or a base station or according to pre-configured information.

[0173] The signaling between terminals for sending or receiving configuration information can include at least one of the following signaling.

[0174] (1) PC5 RRC signaling sent between terminals (e.g., AS configuration, SLRB configuration, SL SIB, or SL MIB)

[0175] (2) PC5 MAC signaling sent between terminals (e.g., sidelink MAC CE)

[0176] (3) PC5 PHY signaling sent between terminals (e.g., PSCCH or sidelink control information)

[0177] In another embodiment, a terminal performing direct communication can obtain feedback signaling transmission information without separate signaling between terminals. According to an embodiment of the present disclosure, regarding the sidelink logical channel identifier (LCID) corresponding to the SLRB of a sidelink flow or a sidelink packet, the sidelink LCIDs where feedback signaling can be transmitted and the sidelink LCIDs where feedback signaling cannot be transmitted can be pre-configured. For example, SL LCID No. 4 to SL LCID No. 10 can be configured as the sidelink LCIDs where feedback signaling is to be sent, and SL LCID No. 11 to SL LCID No. 20 can be configured as the sidelink LCIDs where feedback signaling is not sent. The transmitting terminal and the receiving terminal can determine whether to send feedback signaling based on the LCID information of the SLRB. According to an embodiment of the present disclosure, regarding the hybrid automatic repeat request (HARQ) process ID corresponding to the SLRB of a sidelink flow or a sidelink packet, the sidelink HARQ process IDs where feedback signaling can be transmitted and the sidelink HARQ process IDs where feedback signaling cannot be transmitted can be pre-configured.

[0178] The information in [Table 6] can be included in the above PC5 RRC signaling or PC5 MAC signaling and then sent.

[0179] [Table 6]

[0180]

[0181] The information in Table [7] can be included in the Physical Sidelink Control Channel (PSCCH) or Sidelink Control Information (SCI), and then transmitted.

[0182] [Table 7]

[0183]

[0184] Reference Figure 9a , in operation 901, UE1 900 may obtain configuration information on whether to send feedback signaling for a sidelink flow or sidelink packet corresponding to unicast-based direct communication. Operation 901 may refer to Figures 6a to 8b the embodiments of

[0185] In operation 902, UE1 900 may send AS configuration or SLRB configuration information of a sidelink flow or sidelink packet to UE2 950, and according to an embodiment of the present disclosure, this information may include configuration information on whether to send feedback signaling. The information sent in operation 902 may include [Table 6] above. In operation 902, when the receiving terminal sends feedback signaling, the feedback configuration information available to the receiving terminal may be transmitted together. The signaling performed in operation 902 corresponds to at least one of PC5 RRC unicast signaling or multicast signaling. In operation 903, UE2 950 may send a configuration completion message as a response to the AS configuration or SLRB configuration of the sidelink flow or sidelink packet.

[0186] Reference Figure 9b , in operation 911, UE1 900 may obtain configuration information on whether to send feedback signaling for a sidelink flow or sidelink packet corresponding to unicast-based direct communication. Operation 911 may refer to Figures 6a to 8b the embodiments of

[0187] According to an embodiment of the present disclosure, the case of configuring whether to send feedback signaling in PC5 MAC signaling may operate similarly to the cases shown in Figure 9a or Figure 9b . PC5 MAC signaling may be used instead of PC5 RRC signaling.

[0188] Reference Figure 9c In operation 921, UE1 900 may obtain configuration information on whether to send feedback signaling for a sidelink flow or sidelink packet corresponding to unicast-based direct communication. Operation 921 may refer to Figures 6a to 8b the embodiments. In operation 922, UE1 900 may send SCI information of a sidelink flow or sidelink packet to UE2 950, and according to an embodiment of the present disclosure, the information may include configuration information on whether to send feedback signaling. The information sent in operation 922 may include [Table 7] above.

[0189] For example, information indicating whether to send feedback signaling in the PSCCH SCI may be indicated by a HARQ feedback enable indicator.

[0190]

[0191] (Feedback signaling to be sent when a packet is not successfully received may be configured for a specific application or a specific broadcast type. However, the present disclosure is described under this assumption, that is, if a packet is successfully received, an ACK is sent, and if a packet is not successfully received, a NAK is sent.)

[0192] If the HARQ feedback enable indicator is configured to 1, the receiving terminal may recognize that the transmission of feedback signaling for the packet or flow corresponding to the SCI is indicated, and then send feedback for the packet or flow. If the HARQ feedback enable indicator is configured to 0, the receiving terminal may recognize that the transmission of feedback signaling for the packet or flow corresponding to the SCI is not indicated, and then may not send feedback for the packet or flow.

[0193] As another example, information indicating whether to send feedback signaling in the PSCCH SCI may be indicated by PQI_R or PQI_L. The PSCCH SCI includes at least one of PQI_R or PQI_L.

[0194]

[0195]

[0196] When receiving an SCI including PQI-R or PQI-L, the receiving terminal may apply a reliability threshold to PQI-R and a latency threshold to PQI-L for the packet or flow corresponding to the SCI based on the conditions in [Table 2] above, and determine whether to send feedback signaling.

[0197] Next, with reference to Figure 10a or Figure 10b the operations of a transmitting terminal and a receiving terminal according to an embodiment of the present disclosure will be described.

[0198] Reference Figure 10a , when transmitting a packet from a higher layer of a transmitting terminal in operation 1001, in operation 1002, the transmitting terminal may send the packet to a receiving terminal. In operation 1003, the transmitting terminal may determine whether to send feedback signaling for the packet according to Figures 6a to 9c the method. If, according to the determination in operation 1003, the packet is a packet for which feedback signaling is transmittable, then in operation 1004, the transmitting terminal may monitor the feedback channel. If, according to the determination in operation 1003, the packet is a packet for which feedback signaling is not sent, then the transmitting terminal may proceed to operation 1001.

[0199] Reference Figure 10b , in operation 1011, the receiving terminal may receive a packet from the transmitting terminal. In operation 1012, according to Figures 6a to 9c the method, the receiving terminal may determine whether the packet is subject to the transmission of feedback signaling. If, according to the determination in operation 1012, the packet is subject to the transmission of feedback signaling, then in operation 1013, the receiving terminal may send feedback in the feedback channel. If, according to the determination in operation 1012, the packet is not subject to the transmission of feedback signaling, then the receiving terminal may proceed to operation 1011.

[0200] Next, reference Figures 11a to 11c will describe the signal exchange between a terminal and a base station for processing feedback signaling transmission resources according to an embodiment of the present disclosure.

[0201] Reference Figure 11a , in operation 1101, the terminal may determine whether a sidelink packet or flow is subject to the transmission of feedback signaling. If feedback signaling needs to be transmitted, then in operation 1102, the terminal may request from the base station the sidelink feedback resources required for transmitting the feedback signaling. In operation 1103, the base station may allocate the sidelink feedback resources to the terminal.

[0202] Reference Figure 11b , in operation 1111, the base station may allocate sidelink data resources and sidelink feedback resources to the terminal. The base station may allocate resources (packets and feedback) to be used for sidelink unicast or sidelink multicast. In operation 1112, the terminal may determine whether a sidelink flow or sidelink packet is subject to the transmission of feedback signaling. If it is determined that feedback signaling needs to be transmitted, then in operation 1113, the terminal may send the feedback signaling by using the sidelink feedback resources allocated by the base station in operation 1111.

[0203] Reference Figure 11c, in operation 1121, the base station may allocate a sidelink data resource pool and a sidelink feedback resource pool to the terminal. The resource pools may correspond to the resource pools (packets and feedback) to be used in sidelink unicast or sidelink multicast. In operation 1122, the terminal may determine whether a sidelink flow or a sidelink packet is subject to the transmission of feedback signaling. If it is determined that feedback signaling needs to be transmitted, then in operation 1123, the terminal may request the base station to allocate the resources required for transmitting the sidelink feedback in the resource pools allocated in operation 1121. In operation 1124, the base station may allocate the resources required for the terminal to send sidelink feedback.

[0204] Figures 6a to 11c The method can be used as an embodiment for processing whether to send feedback signaling for V2X packets transmitted or received through device-to-device communication based on unicast or multicast. In the case of multicast, if there is no PC5 RRC unicast connection between terminals, after configuring the PC5 RRC unicast connection, the configuration information for determining whether to send feedback signaling according to the embodiments of the present disclosure can be processed.

[0205] Next, according to various embodiments of the present disclosure, a method for configuring parameters for determining the application of the RLC acknowledged mode (AM) or the RLC unacknowledged mode (UM) in the transmission or reception of V2X packets through device-to-device communication will be described.

[0206] When the RLC AM mode is applied, ARQ can be used to improve the reliability of packet transmission. The RLC AM mode can be applied to V2X applications where reliability is more important than latency. The RLC UM mode can be applied to V2X applications where latency is more important than reliability.

[0207] As in the Figures 6a to 9c embodiment, parameters for determining the application of the RLC AM mode or the RLC UM mode in direct communication can be obtained through at least one of the configuration information in RRC dedicated signaling, V2X SIB signaling, and pre-configuration. The configuration information can be transmitted through PC5 signaling between terminals (e.g., PC5 RRC bearer configuration) or Uu RRC signaling between the terminal and the base station (e.g., RRC re-configuration for SL bearer configuration). In addition, this method can also be applied, where LCIDs are pre-configured in the SL LCID of the SLRB corresponding to the sidelink flow or sidelink packet to apply the RLC AM mode and pre-configured LCIDs to apply the RLC UM mode. For example, SL LCID numbers 4 to 10 can be configured for the application of the RLC AM mode. For example, SL LCID numbers 11 to 20 can be configured for the application of the RLC UM mode.

[0208] In addition to the feedback signaling method, a HARQ retransmission method for retransmitting packets without feedback can be applied to correspond to the reliability requirement value or latency requirement value of a sidelink packet or flow. The combination of the HARQ retransmission method and the feedback signaling method can correspond to one of the following combinations. The terminal or the base station can determine which combination to use according to the radio conditions and the service criteria of the sidelink packet or flow.

[0209] 1. If HARQ feedback is disabled, HARQ retransmission is disabled

[0210] 2. If HARQ feedback is disabled, HARQ retransmission is enabled

[0211] 3. If HARQ feedback is enabled, HARQ retransmission is disabled

[0212] 4. If HARQ feedback is enabled, HARQ retransmission is enabled

[0213] In the case where the HARQ retransmission method is applied to sidelink unicast, the transmitting terminal can determine HARQ retransmission, mark whether retransmission is performed in the SCI information, and send the SCI information, and the receiving terminal can refer to the SCI information to determine whether to perform HARQ retransmission.

[0214] As shown in Figure 4, in the case where the HARQ retransmission method and the feedback signaling method are used together, as an example, feedback signaling can be sent for each packet (including the initially transmitted packet and the packet retransmitted by retransmission). That is, an ACK or NACK can be sent for each packet.

[0215] In another example, the feedback signaling can be configured to send a NACK when the reception of all packets (including the initially transmitted packet and the packet retransmitted by retransmission) fails. The feedback signaling can be configured to send an ACK when at least one packet (including the initially transmitted packet and the packet retransmitted by retransmission) is received.

[0216] Based on Figures 6a to 11c various examples, the operations of the terminal and the base station have been discussed in the case where the determination of enabling or disabling HARQ feedback for an SL flow or an SL packet is performed by the terminal or by the base station. Based on Figures 12 to 14 , the operations of the terminal and the base station will be described according to which entity (the terminal or the base station) will determine the enabling / disabling of HARQ feedback and which entity (the terminal or the base station) will allocate SL grants according to the determination of the enabling / disabling of HARQ feedback.

[0217] According to various embodiments of the present disclosure, HARQ feedback can be applied to each SL resource pool. For example, if HARQ feedback is enabled for SL resource pool A, a terminal that has received a packet transmitted using the resources in pool A can send HARQ feedback for that packet. As another example, if HARQ feedback is disabled for SL resource pool B, a terminal that has received a packet transmitted using the resources in pool B may not send HARQ feedback for that packet. Therefore, in a case where it is determined that HARQ feedback is required for an SL flow or an SL packet, the terminal and the base station need to be operated to select resources from the SL resource pool in which HARQ feedback is enabled. In a case where it is determined that HARQ feedback is not required for an SL flow or an SL packet, the terminal and the base station need to be operated to select resources from the SL resource pool in which HARQ feedback is disabled.

[0218] Figure 12 is a diagram showing a signal flow in which a terminal transmits HARQ feedback assistance information to a base station according to an embodiment of the present disclosure.

[0219] Figure 12 Embodiments can be used in a case where the base station allocates an SL grant to a terminal in the RRC_CONNECTED state or the terminal allocates an SL grant by itself according to an indication from the base station. In a case where the base station allocates an SL grant to the terminal (mode 1), it is required that the base station select an SL resource pool related to whether to send HARQ feedback based on information of the terminal and allocate an SL grant from the corresponding pool. For this purpose, it is required that the base station obtain information on whether to send HARQ feedback from the terminal. In a case where the terminal allocates an SL grant by itself according to an indication from the base station (mode 2), it is required that the base station select an SL resource pool related to whether to send HARQ feedback based on information of the terminal and instruct the terminal to allocate an SL grant from the corresponding pool by itself. For this purpose, it is required that the base station obtain information on whether to send HARQ feedback from the terminal.

[0220] Reference Figure 12 , at operation 1201, the terminal 1200 can send a message including information on whether to send HARQ feedback to the base station 1250. The message used in operation 1201 can be replaced with a SidelinkUEInformation message or a UEAssistanceInformation message. The SidelinkUEInformation message or the UEAssistanceInformation message sent from the terminal to the base station can include at least one piece of information or a combination of multiple pieces of information in the following [Table 8].

[0221] [Table 8]

[0222]

[0223]

[0224] In operation 1202, the base station may receive information as shown in [Table 8] from the terminal, and may determine to configure for transmitting or receiving HARQ feedback based on the SL HARQ feedback enabling indication information. The base station may decide to directly allocate an SL grant to the terminal (mode 1). If configured for transmitting or receiving HARQ feedback, the base station may allocate an SL grant to the terminal from an SL resource pool in which HARQ feedback is enabled. The SL grant is at least one of a dynamic SL grant, a configured grant type 1, a configured grant type 2, and an SPS SL grant. In operation 1203, the base station may send a message to the terminal including information about the configuration of the SL grant. The configuration of the SL grant sent by the base station to the terminal may include at least one piece of information or a combination of multiple pieces of information in [Table 9] below.

[0225] [Table 9]

[0226]

[0227]

[0228] The above [Table 9] may be sent in the case where the base station directly allocates an SL grant.

[0229] In another embodiment, in operation 1202, the base station may determine, based on the SL HARQ feedback enabling indication information in [Table 8] received from the terminal, that it is not necessary to transmit or receive HARQ feedback. The base station may decide to directly allocate an SL grant to the terminal (mode 1). The base station may allocate an SL grant to the terminal from an SL resource pool in which HARQ feedback is disabled. The SL grant is at least one of a dynamic SL grant, a configured grant type 1, a configured grant type 2, and an SPS SL grant. In operation 1203, the base station may send a message to the terminal including information about the configuration of the SL grant. The configuration of the SL grant may include at least one piece of information or a combination of multiple pieces of information in [Table 9] above.

[0230] As yet another embodiment, in operation 1202, the base station may decide to instruct the terminal to allocate an SL grant by itself (mode 2). If configured for transmitting or receiving HARQ feedback based on the HARQ feedback enabling indication in [Table 8] above, the base station may provide the terminal with information about the SL resource pool in which HARQ feedback is enabled. In operation 1203, the base station may send a message to the terminal, and the message includes SL grant configuration information of mode 2 instructing the terminal to allocate an SL grant by itself. The configuration of the SL grant may include at least one piece of information or a combination of multiple pieces of information in [Table 10] below.

[0231] [Table 10]

[0232]

[0233]

[0234] In another embodiment, at operation 1202, the base station may determine that no HARQ feedback needs to be sent or received based on the SL HARQ feedback enabling indication information in [Table 8] received from the terminal. The base station may indicate Mode 2 such that the terminal allocates SL grants by itself. The base station may provide the terminal with information about the SL resource pool in which HARQ feedback is configured to be disabled. At operation 1203, the base station may send a message to the terminal, and the message includes SL grant configuration information of Mode 2 indicating that the terminal allocates SL grants by itself. The configuration of the SL grant may include at least one piece of information or a combination of multiple pieces of information in the information in [Table 10] above.

[0235] At operation 1204, based on the information (Table 9 or Table 10) about the configuration of the SL grant received from the base station, the base station may allocate an SL grant to the terminal, or the terminal may allocate an SL grant by itself from the SL resource pool according to the indication of the base station. If the base station allocates an SL grant (Mode 1) at operation 1204, the base station may select an SL grant from the SL resource pool corresponding to HARQ feedback enabling. As another embodiment, if the base station allocates an SL grant (Mode 1) at operation 1204, the base station may select an SL grant from the SL resource pool corresponding to HARQ feedback disabling. As yet another embodiment, if at operation 1204 (Mode 2), the terminal allocates an SL grant by itself according to the indication of the base station, the terminal may select an SL grant from the SL resource pool corresponding to HARQ feedback enabling indicated by the base station. As yet another embodiment, if at operation 1204 (Mode 2), the terminal allocates an SL grant by itself according to the indication of the base station, the terminal may select an SL grant from the SL resource pool corresponding to HARQ feedback disabling indicated by the base station.

[0236] The terminal may send packets in the SL grant allocated by the base station and / or the SL grant allocated by the terminal itself, and may perform an operation of monitoring the reception of HARQ feedback from the receiving terminal according to the HARQ feedback enabling indication of operation 1201 (in the case of HARQ feedback enabling), or may perform an operation of not monitoring the reception of HARQ feedback (in the case of HARQ feedback disabling).

[0237] Figure 13 It is a diagram showing operations according to an embodiment of the present disclosure, where the terminal selects sidelink resources by itself according to whether to send HARQ feedback.

[0238] Figure 13 Embodiments can be used in cases where a terminal in the RRC_IDLE, RRC_INACTIVE, or OUT_OF_COVERAGE state allocates SL grants by itself.

[0239] Referring to Figure 13 , in operation 1301, a terminal in the RRC_IDLE, RRC_INACTIVE, or OUT_OF_COVERAGE state can determine whether side - link resources need to be allocated to send a packet. If resource allocation is required, then in operation 1302, the terminal can determine whether HARQ feedback for the SL flow or SL packet corresponding to the packet is required. Whether HARQ feedback is required can be determined according to at least one or a combination of [Table 1] to [Table 7] above.

[0240] If it is determined in operation 1303 that HARQ feedback for the packet is required, then in operation 1304, the terminal can allocate an SL grant from a side - link resource pool in which HARQ feedback is enabled. In operation 1306, the terminal can send the packet by using the SL grant. Or, if it is determined in operation 1303 that HARQ feedback for the packet is not required, then in operation 1305, the terminal can allocate an SL grant from a side - link resource pool in which HARQ feedback is disabled and can proceed to operation 1306 to send the packet by using the SL grant. The SL grant allocated by the Figure 13 terminal in can correspond to at least one of a dynamic SL grant, a configured grant type 1, a configured grant type 2, or an SPS SL grant.

[0241] Figure 14 is a diagram showing the operations of a terminal according to an embodiment of the present disclosure.

[0242] Referring to Figure 14 , in operation 1401, the terminal can determine whether to send HARQ feedback for an SL flow or an SL packet. In operation 1402, the terminal can determine whether the terminal is in the RRC_CONNECTED state. When the terminal is in the RRC_CONNECTED state, the terminal can request the base station to allocate an SL grant.

[0243] When it is determined according to the determination of operation 1402 that the terminal is in the RRC_CONNECTED state, at operation 1403, the terminal may send terminal assistance information for SL grant to the base station. The terminal assistance information may be included in the SidelinkUEInformation message or the UEAssistanceInformation message. The terminal assistance information sent at operation 1403 may include information on whether to send HARQ feedback based on the determination of operation 1401. That is, the SL grant allocation request information for the SL stream or SL packet for which HARQ feedback needs to be transmitted or the SL grant allocation request information for the SL stream or SL packet for which HARQ feedback does not need to be transmitted may be sent from the terminal to the base station.

[0244] At operation 1404, the terminal may receive the SL resource pool configuration from the base station. The SL resource pool configuration information may be sent through the RRC_ConnectionReconfiguration message or the RRC_Reconfiguration message sent by the base station to the terminal. At operation 1405, the terminal may determine whether the base station indicates a mode (mode 1) in which the base station allocates SL grants according to the SL resource pool configuration. If it is determined that the base station is indicated to operate in the mode (mode 1) of allocating SL grants, then at operation 1406, the terminal may receive the SL grant from the base station. The base station may allocate the SL grant from the sidelink resource pool corresponding to HARQ feedback enabled based on the information on whether to send HARQ feedback sent by the terminal at operation 1403, or may allocate the SL grant from the sidelink resource pool corresponding to HARQ feedback disabled.

[0245] At operation 1407, the terminal may send packets of the SL stream or SL packet by using the SL grant. At operation 1407, the terminal may process the packet according to the information related to HARQ feedback enabled or HARQ feedback disabled of the packet determined at operation 1401. For example, if HARQ feedback is configured to be enabled, the terminal may wait for the HARQ feedback of the packet sent in the SL grant. For example, if HARQ feedback is configured to be disabled, the terminal may not wait (monitor) for the HARQ feedback of the packet sent in the SL grant.

[0246] In operation 1405, the terminal can determine whether the base station indicates a mode (mode 2) in which the terminal allocates SL grants by itself according to the SL resource pool configuration. If it is determined that the base station has indicated the mode (mode 2) in which the terminal allocates SL grants by itself, then in operation 1408, the terminal can allocate an SL grant by itself from the sidelink resource pool indicated in the SL resource pool configuration of operation 1404 for allocating SL grants. Based on the information about whether to send HARQ feedback sent by the terminal in operation 1403, the sidelink resource pool indicated by the base station can correspond to the sidelink resource pool corresponding to HARQ feedback enabled, or can correspond to the sidelink resource pool corresponding to HARQ feedback disabled. The terminal can allocate an SL grant from the sidelink resource pool corresponding to HARQ feedback enabled or the sidelink resource pool corresponding to HARQ feedback disabled according to the information related to HARQ feedback enabled or HARQ feedback disabled determined for the packet in operation 1401.

[0247] In operation 1409, the terminal can send a packet corresponding to an SL flow or an SL packet by using the SL grant allocated in operation 1408. For example, if HARQ feedback is configured to be enabled, the terminal can wait for the HARQ feedback of the packet sent in the SL grant. For example, if HARQ feedback is configured to be disabled, the terminal may not wait for the HARQ feedback of the packet sent in the SL grant.

[0248] If, according to the determination in operation 1402, the terminal is not in the RRC_CONNECTED state, then the terminal can be in at least one of the RRC_IDLE, RRC_INACTIVE, or OUT_OF_COVERAGE states. If the terminal is in at least one of the RRC_IDLE, RRC_INACTIVE, or OUT_OF_COVERAGE states, the terminal can allocate an SL grant from the SL resource pool by itself.

[0249] In operation 1410, the terminal may determine whether to enable HARQ feedback based on the determination information related to whether HARQ feedback needs to be sent for the SL flow or SL packet determined in operation 1401. If it is determined in operation 1410 that HARQ feedback enabling is configured for the SL flow or SL packet, then in operation 1411, the terminal may allocate an SL grant from the sidelink resource pool corresponding to the HARQ feedback enabling. In operation 1412, the terminal may send a packet corresponding to the SL flow or SL packet by using the SL grant allocated in operation 1411. In addition, in operation 1412, the terminal may wait for the HARQ feedback of the packet sent in the SL grant. Alternatively, if it is determined in operation 1410 that HARQ feedback disabling is configured for the SL flow or SL packet, then in operation 1413, the terminal may allocate an SL grant from the sidelink resource pool corresponding to the HARQ feedback disabling.

[0250] In operation 1414, the terminal may send a packet corresponding to the SL flow or SL packet by using the SL grant allocated in operation 1413. In addition, the terminal may not wait for the HARQ feedback of the packet sent in the SL grant.

[0251] According to an embodiment of the present disclosure, the operation of the terminal to perform a logical channel prioritization process on a logical channel corresponding to an SL flow or SL packet with HARQ feedback enabling or a logical channel corresponding to an SL flow or SL packet with HARQ feedback disabling is as follows.

[0252] The terminal may select a destination identifier of a logical channel that satisfies the following conditions. The destination identifier may correspond to at least one of unicast, multicast, and broadcast. The terminal may select a destination identifier of the logical channel with the highest transmission priority among the logical channels that satisfy the following conditions. If there are one or more destination identifiers of the logical channel that satisfy the conditions and have the highest transmission priority, the terminal may select a random destination.

[0253] (1) The logical channel has data to be sent

[0254] (2) There is a logical channel whose SBj value is greater than 0.

[0255] For each logical channel, the initial value of the SBj value is configured to 0. At each time point where the logical channel priority processing procedure is executed, the SBj value is incremented by (sPBR X T). sPBR corresponds to the sidelink priority bit rate. T is the time consumed from the time point at which the previous SBj value was calculated to the current point. If the SBj value becomes greater than the sidelink bucket size (sPBR X sBSD), the SBj value is configured to the sidelink bucket size. sBSD corresponds to the sidelink bucket size duration. The SBj value can be manipulated to prevent starvation, where a logical channel is not given a transmission opportunity and thus cannot send SL flows or SL packets of the logical channel.

[0256] (3) If the SL grant permits configuring grant type 1, then configure grant type 1 for the corresponding logical channel.

[0257] (4) If the SL grant permits HARQ feedback, then enable HARQ feedback configuration for the corresponding logical channel.

[0258] The terminal can select a logical channel that meets the following conditions for the selected destination identifier.

[0259] (1) The logical channel has data to be sent

[0260] (2) If the SL grant permits configuring grant type 1, then configure grant type 1 for the corresponding logical channel.

[0261] (3) If the SL grant permits HARQ feedback, then enable HARQ feedback configuration for the corresponding logical channel.

[0262] The terminal can send an SL flow or SL packet corresponding to the selected logical channel through the SL grant. In an embodiment, if HARQ feedback enabling is configured for the selected logical channel, then the transmission can be performed through the SL grant with HARQ feedback enabled. If HARQ feedback enabling is configured and multiple logical channels are selected, then the SL flows or SL packets corresponding to the multiple logical channels can be sent through the SL grant with HARQ feedback enabled. In an embodiment, if HARQ feedback disabling is configured for the selected logical channel, then the transmission can be performed through the SL grant with HARQ feedback disabled. If HARQ feedback disabling is configured and multiple logical channels are selected, then the SL flows or SL packets corresponding to the multiple logical channels can be sent through the SL grant with HARQ feedback disabled.

[0263] According to an embodiment of the present disclosure, if it is determined that HARQ feedback disabling or HARQ feedback enabling is configured for a logical channel corresponding to an SL flow or an SL packet, but a HARQ feedback disabling resource pool is configured and a HARQ feedback enabling resource pool is not configured, the terminal may ignore the HARQ feedback disabling or HARQ feedback enabling configuration configured for the logical channel corresponding to the SL flow or the SL packet, and may operate according to the HARQ feedback disabling configuration configured in the resource pool. That is, it is determined that HARQ feedback disabling is configured for the resource pool, so the terminal may perform operations in a case where HARQ feedback disabling is configured for the logical channel of the SL flow or the SL packet.

[0264] The methods disclosed in this claim book and / or the methods according to various embodiments described in the specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0265] When these methods are implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within an electronic device. At least one program may include instructions that cause the electronic device to execute the methods according to various embodiments of the present disclosure defined by the appended claims and / or disclosed herein.

[0266] The programs (software modules or software) may be stored in non-volatile memories, including random access memories and flash memories, read-only memories (ROMs), electrically erasable programmable read-only memories (EEPROMs), magnetic disk storage devices, compact disc-ROMs (CD-ROMs), digital versatile discs (DVDs), or other types of optical storage devices, or magnetic tape cartridges. Or, any combination of some or all of them may form a memory in which the programs are stored. In addition, multiple such memories may be included in the electronic device.

[0267] In addition, these programs may be stored in an attachable storage device, and the storage device may access the electronic device through a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), and a storage area network (SAN), or a combination thereof. Such a storage device may access the electronic device via an external port. In addition, a separate storage device on the communication network may access a portable electronic device.

[0268] In the above detailed embodiments of the present disclosure, according to the presented detailed embodiments, the elements included in the present disclosure are expressed in singular or plural forms. However, for ease of description, the singular or plural form is appropriately selected for the presented situation, and the present disclosure is not limited to the elements expressed in singular or plural forms. Therefore, the elements expressed in plural may also include a single element, or the elements expressed in singular may also include multiple elements.

[0269] Although specific embodiments have been described in the detailed description of the present disclosure, various modifications and changes can be made without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be defined as limited to the embodiments, but should be defined by the appended claims and their equivalents.

Claims

1. A method performed by a first terminal in a wireless communication system, the method comprising: receiving, from a base station, a sidelink radio bearer configuration via a radio resource control (RRC) message dedicated to the first terminal, the sidelink radio bearer configuration including first information regarding sidelink hybrid automatic repeat request (HARQ) feedback set to enabled or disabled for a logical channel; selecting at least one logical channel from among a plurality of logical channels, wherein the at least one logical channel has sidelink data to be transmitted and is configured to set sidelink HARQ feedback to enabled based on the first information; obtaining a media access control (MAC) protocol data unit (PDU) that includes the sidelink data of the at least one selected logical channel; setting a HARQ feedback enable / disable indicator to enabled based on the first information; transmitting the MAC PDU and the HARQ feedback enable / disable indicator set to enabled to a second terminal; and monitoring feedback information related to the MAC PDU.

2. The method according to claim 1, further comprising: transmitting a sidelink user equipment (UE) information message to the base station to request allocation of a sidelink radio bearer configuration, wherein the sidelink UE information message includes information regarding a destination identifier, information regarding a broadcast type, or information regarding quality of service (QoS) of a sidelink flow, wherein an RRC message is received based on the sidelink UE information message in an RRC connected state.

3. The method according to claim 1, wherein the RRC message further includes information about a resource pool for the sidelink, and wherein sidelink data of another logical channel configured with sidelink HARQ feedback set to disabled is not multiplexed in the MAC PDU.

4. The method according to claim 3, wherein the feedback information is monitored based on the information about the resource pool.

5. A first terminal in a wireless communication system, the first terminal comprising: a transceiver; and a controller configured to: control the transceiver to receive, from a base station, a sidelink radio bearer configuration via a radio resource control (RRC) message dedicated to the first terminal, the sidelink radio bearer configuration including first information regarding sidelink hybrid automatic repeat request (HARQ) feedback set to enabled or disabled for a logical channel, select at least one logical channel from among a plurality of logical channels, wherein the at least one logical channel has sidelink data to be transmitted and is configured to set sidelink HARQ feedback to enabled based on the first information, obtain a media access control (MAC) protocol data unit (PDU) that includes the sidelink data of the at least one selected logical channel, set a HARQ feedback enable / disable indicator to enabled based on the first information, control the transceiver to transmit the MAC PDU and the HARQ feedback enable / disable indicator set to enabled to a second terminal, and monitor feedback information related to the MAC PDU.

6. The first terminal according to claim 5, The controller is further configured to: control the transceiver to send a sidelink user equipment (UE) information message to the base station to request allocation of sidelink radio bearer configuration, wherein the sidelink UE information message includes information about a destination identifier, information about a broadcast type, or information about the quality of service (QoS) of a sidelink flow, and receive an RRC message based on the sidelink UE information message in the RRC connected state.

7. The first terminal according to claim 5, wherein the RRC message further includes information about a resource pool for the sidelink, and sidelink data of another logical channel configured with sidelink HARQ feedback set to be disabled is not multiplexed in the MAC PDU.

8. The first terminal according to claim 7, wherein feedback information is monitored based on the information about the resource pool.

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